Wikicars - User contributions [en]

File:Cardan Shaft.jpg

2006-06-28T22:08:23Z

Philip rosenblum:

Driveshaft

2006-06-28T22:07:42Z

Philip rosenblum:

{{dablink|This article is about the mechanical device. For the fictional music group from the American television series ''Lost'', see [[Drive Shaft]].}}

[[Image:Cardan Shaft.jpg|thumb|200px|Cardan driveshaft with universal joints]]
A '''driveshaft''' or '''driving shaft''' or Cardan shaft is a [[machine|mechanical device]] for [[transmission (mechanics)|transferring]] [[power (physics)|power]] from the [[engine]] or [[motor]] to the point where useful [[Mechanical work|work]] is applied.

Most engines or motors deliver power as [[torque]] through rotary motion: this is extracted from the linear motion of [[piston]]s in a [[reciprocating engine]]; [[water]] driving a [[water wheel]]; or forced air or water in a [[turbine]]. From the point of delivery, the components of power transmission form the drive train.

Driveshafts are carriers of torque: they are subject to [[torsion (mechanics)|torsion]] and [[shear stress]], which represents the difference between the input [[force]] and the [[load]]. They thus need to be strong enough to bear the stress, without imposing too great an additional [[inertia]] by virtue of the weight of the shaft.

==Automotive driveshafts==
Most [[automobile]]s today use rigid driveshafts to deliver power from a transmission to the wheels. A pair of short driveshafts is commonly used to send power from a central [[differential (mechanics)|differential]], [[transmission]], or [[transaxle]] to the wheels.

In [[FR layout|front-engined, rear-drive]] vehicles, a longer driveshaft is also required to send power the length of the vehicle. Two forms dominate: The [[torque tube]] with a single [[universal joint]] and the [[Hotchkiss drive]] with two or more joints. This system became known as ''[[Systeme Panhard]]'' after the automobile company, [[Panhard et Levassor]] patented it.

Early automobiles often used [[chain drive]] or [[belt drive]] mechanisms rather than a driveshaft. Some even used electrical generators and motors to transmit power to the wheels.

In British English, the term "driveshaft" is restricted to a transverse shaft which transmits power to the wheels, especially the front wheels. A driveshaft connecting the gearbox to a rear differential is called a [[propeller shaft]] (or more commonly a "prop-shaft") and a driveshaft connecting a rear differential to a rear wheel is usually called a '''halfshaft'''. The name derives from the fact that two such shafts are required to form one rear axle.

There are different types of driveshafts in Automotive Industry:
* 1 piece driveshaft
* 2 piece driveshaft
* Slip in Tube driveshaft

The Slip in Tube Driveshaft is the new type which also helps in Crash Energy Management. It can be compressed in case of crash. It is also known as a collapsible driveshaft.

==Marine driveshafts==
On a power-driven ship, the driveshaft, or [[propeller shaft]], usually connects the transmission inside the vessel directly to the [[propeller]], passing through a [[stuffing box]] or other seal at the point it exits the [[hull (watercraft)|hull]].

As the rotating propeller pushes the vessel forward, the marine driveshaft is also subject to [[Physical compression|compression]], and when going reverse, to [[tension (mechanics)|tension]].

[[Category:Automotive technologies]]

[[cs:Hřídel]]
[[de:Welle (Mechanik)]]
[[es:palier]]
[[fr:Cardan (mécanique)]]
[[it:Giunto cardanico]]
[[io:Ax-arboro]]
[[sv:Kardanaxel]]

Distance sensor

2006-06-28T22:06:18Z

Philip rosenblum:

A '''distance sensor''' is an electronic device that translates each rotation of the [[driveshaft]] into several electronic pulses. The number of pulses generated are directly proportional to the distance traveled.
These are used by:
* [[Speedometer]]s to indicate the speed.
* [[Odometer]]s to indicate the distance traveled.
* [[Taximeter]]s to determine the ride fare.

[[Category:Automotive technologies]]
[[Category:Auto parts]]
[[Category:Measuring instruments]]

{{auto-part-stub}}

File:FAP-Filter Peugeot.jpg

2006-06-28T22:04:14Z

Philip rosenblum:

Diesel Particulate Filter

2006-06-28T22:03:49Z

Philip rosenblum:

[[Image:FAP-Filter Peugeot.jpg|thumb|Diesel Particulate Filter (top left) in a Peugeot]]
A '''Diesel Particulate Filter''', sometimes called a '''DPF''', is used to remove [[Diesel Particulate Matter]] (including [[soot]]) from the [[exhaust gas]] of a [[diesel engine]]. Unlike a [[catalytic converter]] which is a flow-through device, a DPF cleans exhaust gas by forcing the gas to flow through the wall of the filter. DPFs are made of several materials, the most common being [[cordierite]] (a ceramic material that is also used as catalytic converter supports (= cores)) and [[silicon carbide]]. The devices look like catalytic converter cores that have had alternate channels plugged - the plugs force the exhaust gas to flow through the wall and the particulate collects on the inlet face.

The DPF has several channels in parallel with the ends plugged, in a [[checkerboard]] pattern. A DPF is usually followed by a lean [[NOx]] [[catalyst]] in a proprietary catalytic converter for diesel engines. By trapping the particulate matter, soot, the DPF allows the lean NOx catalyst to work without being clogged by the soot. Hence the effectiveness of the lean NOx catalyst is not reduced by soot covering the active sites of the catalytic converter.

These '''particle filters''' are a new technology: high cost [[catalytic]] [[pollution]] control module added to [[diesel engine]]d cars to eliminate the characteristic black smoke trail. It was first offered as standard by the French manufacturer [[PSA Peugeot Citroën]] in early [[2005]]. Slow adoption by the [[Germany|German]] car industry sparked local protests in [[March 2005]]. Despite costs, the device will be mandatory for all newly built vehicles in the [[EU]] starting in [[2007]] (projected).

==The filter getting clogged==
In most forms the exhaust gas is forced to flow through a material with extremely tiny pores, achieveing very high filtration rates even on nano-particles; however, this type of filter may become blocked by soot if there is not a mechanism to oxidize the accumulation, or if that mechanism fails. In any case, [[engine oil]] ash will build up on the face of the filter, needing periodic cleaning (unlike a [[Diesel Oxidation Catalyst]] which can often last the life of the engine without maintenance).

Several forms called "leaky filters" have also been devised, which are supposed to be incapable of being plugged, however their filtration efficiency seldom rises above 60%, and they have a tendency to "blow off" accumulated particulates after some hours of operation.

Regeneration is the process of removing the accumulated soot from the filter. This is done either:-
*Passively (by additing a catalyst to the filter).
*Actively. Active filter management can use a variety of strategies such as using engine management to increase exhaust temperature or using microwave energy or resistive heating coils to heat the filter core. In this soot burn-off, the DPF is heated to a temperature that fully burns the soot. This lets the DPF be used continuously; however, it uses extra fuel, which is burnt to heat the DPF. A sensor that measures back pressure decides when the DPF needs to be heated. A properly designed filter will have little effect on fuel usage, and an improperly designed filter can be catastrophic.

Back-pressure should be avoided in a large diesel engine's exhaust system, as the exhaust gas should be allowed to cool down as much as possible by drop in pressure as it leaves the engine's cylinders, else the exhaust valve may get damaged by overheating.

==Where used==
DPF's are in common use in Europe where [[Peugeot]] introduced them as standard fit on passenger cars. The Peugeot system uses a combination of engine management, and a [[fuel borne catalyst]] to regenerate the filters.

In [[North America]] filters are used heavily on diesel-powered underground mining machines, and also on transit buses, and the filters are installed as "[[retro]]fit" devices (i.e. not factory fitted).

In [[Japan]] the [[Prefecture of Tokyo]] passed a law banning trucks without filters from entering the city limits.

Increasingly stringent regulations mean that filter technology will soon be fitted as standard to engines worldwide.

== See also ==
[[Diesel Particulate Matter]]

[[Category:Automotive technologies]]
[[Category:Automotive accessories]]
[[Category:Engine technology]]
[[Category:Filters]]

[[de:Partikelfilter]]
[[fr:Filtre à particules]]

Delay box

2006-06-28T22:02:56Z

Philip rosenblum:

'''Delay box''' is a device used in [[drag racing]], allowing a racer to launch the vehicle with the same reaction time on every pass. This device requires a [[transbrake]] in order to function, and sometimes a two-step [[rev limiter]] is also used. Before pulling up to the "Christmas Tree" as the group of lights at the beginning of the racetrack is known, the racer dials in how long it will take for the tree to countdown to the green lights. This time is set in the delay box and the racer then readies himself for the first yellow light to appear on the tree by holding down the switch which arms the delay box and pressing the accelerator to the floor. When the first yellow comes on, the racer releases the switch for the delay box, and the device begins a countdown at the same time as the tree, releasing the transbrake (and canceling the first stage rev limiter, if used) at the same time as the tree flashes green.

[[Category:Drag racing]]
[[Category:Automotive technologies]]

DIN 72552

2006-06-28T22:01:13Z

Philip rosenblum:

'''DIN 72552''' is a [[DIN]] standard for [[Automobile]] electric terminal numbers, [[standardization|standard]]izing almost every contact in an automobile with a number code.

This table gives most frequently used numbers.

{| border="1" cellspacing="0" cellpadding="2"
|-
! Contact
! Meaning
|-
! colspan="2" | [[Ignition system]]
|-
| 1
| [[coil]], [[distributor]], low voltage
|-
| 1a, 1b
| distributor with two separate circuits
|-
| 2
| breaker points magneto ignition
|-
| 4
| coil, distributor, high voltage
|-
| 4a, 4b
| distributor with two separate circuits, high voltage
|-
| 7
| terminal on ballast [[resistor]], to distributor
|-
| 15
| [[battery (electricity)|battery]]+ from ignition switch
|-
| 15a
| from ballast resistor to coil and starter motor
|-
! colspan="2" | preheat ([[diesel engine]]s)
|-
| 15
| preheat in
|-
| 17
| start
|-
| 19
| preheat (glow)
|-
| 50
| starter control
|-
! colspan="2" | Battery
|-
| 15
| battery+ through ignition switch
|-
| 30
| from battery+ direct
|-
| 30a
| from 2nd battery and 12/24 [[volt|V]] [[relay]]
|-
| 31
| return to battery- or direct to ground
|-
| 31a
| return to battery- 12/24 V relay
|-
| 31b
| return to battery- or ground through switch
|-
| 31c
| return to battery- 12/24 V relay
|-
! colspan="2" | [[Electric motor]]s
|-
| 32
| return
|-
| 33
| main terminal (swap of 32 and 33 is possible)
|-
| 33a
| limit
|-
| 33b
| field
|-
| 33f
| 2. slow [[rpm]]
|-
| 33g
| 3. slow rpm
|-
| 33h
| 4. slow rpm
|-
| 33L
| rotation left
|-
| 33R
| rotation right
|-
! colspan="2" | turn indicators
|-
| 49
| flasher unit in
|-
| 49a
| flasher unit out, indicator switch in
|-
| 49b
| out 2. flasher circuit
|-
| 49c
| out 3. flasher circuit
|-
| C
| 1st flasher indicator light
|-
| C2
| 2nd flasher indicator light
|-
| C3
| 3rd flasher indicator light
|-
| L
| indicator lights left
|-
| R
| indicator lights right
|-
| L54
| lights out, left
|-
| R54
| lights out, right
|-
! colspan="2" | [[alternating current|AC]] [[generator]]
|-
| 51
| [[Direct current|DC]] at [[rectifier]]s
|-
| 51e
| as 51, with choke coil
|-
| 59
| AC out, rectifier in, light switch
|-
| 59a
| charge, rotor out
|-
| 64
| generator control light
|-
! colspan="2" | Generator, Generator [[voltage regulator]]
|-
| 61
| charge control light
|-
| B+
| Battery +
|-
| B-
| Battery -
|-
| D+
| [[Dynamo]] +
|-
| D-
| Dynamo -
|-
| DF
| Dynamo field
|-
| DF1
| Dynamo field 1
|-
| DF2
| Dynamo field 2
|-
| U, V, W
| AC three phase terminals
|-
! colspan="2" | lights
|-
| 54
| [[brake]] lights
|-
| 55
| fog light
|-
| 56
| spot light
|-
| 56a
| [[headlight]] high beam and indicator light
|-
| 56b
| low beam
|-
| 56d
| signal flash
|-
| 57
| parking lights
|-
| 57a
| parking lights
|-
| 57L
| parking lights left
|-
| 57R
| parking lights right
|-
| 58
| licence plate lights, instrument panel
|-
| 58d
| panel light dimmer
|-
! colspan="2" | window wiper/washer
|-
| 53
| wiper motor + in
|-
| 53a
| limit stop+
|-
| 53b
| limit stop field
|-
| 53c
| washer pump
|-
| 53e
| stop field
|-
| 53i
| wiper motor with permanent magnet, third brush for high speed
|-
! colspan="2" | acoustic warning
|-
| 71
| [[buzzer|beeper]] in
|-
| 71a
| beeper out, low
|-
| 71b
| beeper out, high
|-
| 72
| hazard lights switch
|-
| 85c
| hazard sound on
|-
! colspan="2" | switches
|-
| 81
| opener
|-
| 81a
| 1 out
|-
| 81b
| 2 out
|-
| 82
| lock in
|-
| 82a
| 1st out
|-
| 82b
| 2nd out
|-
| 82z
| 1st in
|-
| 82y
| 2nd in
|-
| 83
| multi position switch, in
|-
| 83a
| out position 1
|-
| 83b
| out position 2
|-
! colspan="2"| [[Relay]]
|-
| 85
| relay coil -
|-
| 86
| relay coil +
|-
! colspan="2" | Relay contacts
|-
| 87
| common contact
|-
| 87a
| normally closed contact
|-
| 87b
| normally open contact
|-
| 88
| common contact 2
|-
| 88a
| normally closed contact 2
|-
| 88b
| normally open contact 2
|-
! colspan="2" | additional
|-
| 52
| signal from trailer
|-
| 54g
| magnetic valves for trailer brakes
|-
| 75
| Radio, cigarette lighter
|-
| 77
| door valves control
|}

[[Category:Automotive technologies|DIN 72552]]
[[Category:DIN standards]]

File:Modern Hot Rod.jpg

2006-06-28T21:54:57Z

Philip rosenblum:

Custom car

2006-06-28T21:54:45Z

Philip rosenblum:

[[Image:plain painted '32 roadster.jpg|thumb|250px|Plain paint on early hot rods {{3d_glasses}}]]
[[Image:Purple Buick.jpg|thumb|250px|Modern custom of mid-fifities Buick {{3d_glasses}}]]
[[Image:modern steel body.jpg|thumb|250px|Modern steel "Retro style" $100,000+ custom body {{3d_glasses}}]]

A '''custom car''' is phrase that became prominent in American pop culture in the 1950s, and has enjoyed special interest popularity since that time. It relates to a passenger [[automobile|vehicle]] that has been modified to [[engine tuning|improve its performance]] by altering or replacing the [[engine]] and [[transmission (mechanics)|transmission]] and to make it look "unique", unlike any car that might have been factory finished,always a personal "styling" statement by the re-styler/re-builder..

===First came the post war "Hot Rods" made from "Junkers" ===
A development of [[hot rod]]ding, the change in name corresponded to the change in the [[design]] of the cars that were being modified. The first hot rods were made from pre-WWII cars that had [[running board]]s and simple fenders that bent over the wheels. These were modified by removing the running boards and either removing the fenders entirely or replacing them with very light "cycle fenders". The purpose was to put the most powerful engine in the lightest possible frame and body combination. The suspension was usually altered to make the car lower; the front was often made much lower than the rear. Much later some hot rods and custom cars swapped the old solid rear axle for an independent rear axle, often from [[Jaguar]]. Only rarely was the grille of one make of car replaced by another; one exception was that the [[1937]] [[Buick]] grille was often put on a [[Ford Motor Company|Ford]]. The original hot rods were plainly painted like the [[Model A Fords]]
from which they had been built up, and only slowly begun to take on colors, and eventually fancy orange-yellow flamed hoods or "candy-like" deep arcylic finishes in the various colors.

===New Post War, Slab-sided cars weren't good for "Hot Rod" treatment===
With the change in automobile design to encase the wheels in fenders and to extend the hood to the full width of the car, the former practices were no longer possible. In addition, there was tremendous automotive advertising and subsequent public interest in the new models in the [[1950s]]. Hence custom cars came into existence, swapping [[headlight]] rings, grilles, bumpers, [[chrome]] side strips, and tail lights. The bodies of the cars were changed by cutting through the sheet metal, removing bits to make the car lower, welding it back together, and adding a lot of [[lead]] to make the resulting form smooth. By this means, "chopping" made the roof lower; "sectioning" made the body thinner from top to bottom. "Channeling" was cutting knotches in the floorpan where the body touches the frame to lower the whole body. Fins were often added from other cars, or made up from sheet steel. But in the custom car culture, if you were someone who merely changed the appearance without improving the performance substantially, you were looked down on.
Paint was an important concern. Once bodywork was done, the cars were painted unusual colors. Transparent but wildly-colored [[candy- apple paint]], which was applied atop a metallic undercoat, and [[metalflake]] paint, which adds aluminum glitter within candy-apple paint, appeared in the 1960s. These took many coats to produce a brilliant effect -- which in hot climates had a tendency to flake off. Custom cars also continued the habit of adding decorative paint after the main coat was finished, of flames extending rearward from the front wheels, and of scallops and hand-painted pinstripes of a different color than the rest of the car. The latter, most often being of a single coat, would be expected to be of a simpler paint.

Once customizing post-war cars caught on, some of the practices were extended to pre-war cars, which would have been called hot rods that kept their fenders but had more body work done on them. An alternate rule for disambiguation developed that hot rods had the engine behind the front suspension, while custom cars had the engine over the front suspension. The clearest example of this is that [[Ford Motor Company|Fords]] prior to 1949 had [[Henry Ford]]'s old transverse front suspension, while the 1949 model had a more modern suspension with the engine moved forward.

With the coming of the [[muscle car]], and beyond that to the high-performance luxury car, customization declined. One place where it persisted was the US Southwest, where "[[low-rider]]s" were built similar in concept to the earlier customs, but of post-1950s cars.

===Recent trend to build new custom steel bodies based on pre-war designs===
Recently, as the supply of usable antique steel bodies has given out, a new trend to fabricate new steel bodies, closely based on the styling of the pre-war cars. Bodies of this type can cost over $100,000 before the "running gear" is added.

<gallery>
Image:Modern Hot Rod.jpg|Modern, but very Basic '32 roadster {{3d_glasses}}
Image:1951 Mercury.jpg|Recent custom job on a '51 Mercury {{3d_glasses}}
Image:1940 Ford.jpg|thumb|250px|Modern Custom {{3d_glasses}}
</gallery>

===See also===
{{commonscat|Custom cars}}
* [[my dream wheels]]
* [[Go-faster stripes]]
* [[Hot rod]]
* [[Kustom Kulture]]
* [[Lowrider]]
* [[Import scene]]
* [[Pimp My Ride]]
* [[PFS Imports]]

== External links ==

* [http://www.customcarsuk.com/ U.K. free site for custom cars]
* [http://www.mydreamwheels.com/ Custom Cars, hot rods, vintage cars]
* [http://www.roddingroundtable.com/ The Rodding Roundtable]
* [http://www.justcustomz.com/gallery/hotrod-pictures.php More Custom Car Pictures]
* [http://www.american-excess.com CAR SHOWS IN BELGIUM ]

[[category:automotive technologies]]
[[Category:Vehicle modification]]
[[Category:DIY Culture]]
[[de:Custom car]]
[[sv:Custom]]

File:Modern 'basic' Hot Rod.jpg

2006-06-28T21:52:18Z

Philip rosenblum:

File:1940 Ford.jpg

2006-06-28T21:51:39Z

Philip rosenblum:

File:1951 Mercury.jpg

2006-06-28T21:51:27Z

Philip rosenblum:

File:Modern steel body.jpg

2006-06-28T21:50:12Z

Philip rosenblum:

File:Purple Buick.jpg

2006-06-28T21:49:55Z

Philip rosenblum:

File:Plain painted '32 roadster.jpg

2006-06-28T21:49:42Z

Philip rosenblum:

Custom car

2006-06-28T21:48:37Z

Philip rosenblum:

[[Image:plain painted '32 roadster.jpg|thumb|250px|Plain paint on early hot rods {{3d_glasses}}]]
[[Image:Purple Buick.jpg|thumb|250px|Modern custom of mid-fifities Buick {{3d_glasses}}]]
[[Image:modern steel body.jpg|thumb|250px|Modern steel "Retro style" $100,000+ custom body {{3d_glasses}}]]

A '''custom car''' is phrase that became prominent in American pop culture in the 1950s, and has enjoyed special interest popularity since that time. It relates to a passenger [[automobile|vehicle]] that has been modified to [[engine tuning|improve its performance]] by altering or replacing the [[engine]] and [[transmission (mechanics)|transmission]] and to make it look "unique", unlike any car that might have been factory finished,always a personal "styling" statement by the re-styler/re-builder..

===First came the post war "Hot Rods" made from "Junkers" ===
A development of [[hot rod]]ding, the change in name corresponded to the change in the [[design]] of the cars that were being modified. The first hot rods were made from pre-WWII cars that had [[running board]]s and simple fenders that bent over the wheels. These were modified by removing the running boards and either removing the fenders entirely or replacing them with very light "cycle fenders". The purpose was to put the most powerful engine in the lightest possible frame and body combination. The suspension was usually altered to make the car lower; the front was often made much lower than the rear. Much later some hot rods and custom cars swapped the old solid rear axle for an independent rear axle, often from [[Jaguar]]. Only rarely was the grille of one make of car replaced by another; one exception was that the [[1937]] [[Buick]] grille was often put on a [[Ford Motor Company|Ford]]. The original hot rods were plainly painted like the [[Model A Fords]]
from which they had been built up, and only slowly begun to take on colors, and eventually fancy orange-yellow flamed hoods or "candy-like" deep arcylic finishes in the various colors.

===New Post War, Slab-sided cars weren't good for "Hot Rod" treatment===
With the change in automobile design to encase the wheels in fenders and to extend the hood to the full width of the car, the former practices were no longer possible. In addition, there was tremendous automotive advertising and subsequent public interest in the new models in the [[1950s]]. Hence custom cars came into existence, swapping [[headlight]] rings, grilles, bumpers, [[chrome]] side strips, and tail lights. The bodies of the cars were changed by cutting through the sheet metal, removing bits to make the car lower, welding it back together, and adding a lot of [[lead]] to make the resulting form smooth. By this means, "chopping" made the roof lower; "sectioning" made the body thinner from top to bottom. "Channeling" was cutting knotches in the floorpan where the body touches the frame to lower the whole body. Fins were often added from other cars, or made up from sheet steel. But in the custom car culture, if you were someone who merely changed the appearance without improving the performance substantially, you were looked down on.
Paint was an important concern. Once bodywork was done, the cars were painted unusual colors. Transparent but wildly-colored [[candy- apple paint]], which was applied atop a metallic undercoat, and [[metalflake]] paint, which adds aluminum glitter within candy-apple paint, appeared in the 1960s. These took many coats to produce a brilliant effect -- which in hot climates had a tendency to flake off. Custom cars also continued the habit of adding decorative paint after the main coat was finished, of flames extending rearward from the front wheels, and of scallops and hand-painted pinstripes of a different color than the rest of the car. The latter, most often being of a single coat, would be expected to be of a simpler paint.

Once customizing post-war cars caught on, some of the practices were extended to pre-war cars, which would have been called hot rods that kept their fenders but had more body work done on them. An alternate rule for disambiguation developed that hot rods had the engine behind the front suspension, while custom cars had the engine over the front suspension. The clearest example of this is that [[Ford Motor Company|Fords]] prior to 1949 had [[Henry Ford]]'s old transverse front suspension, while the 1949 model had a more modern suspension with the engine moved forward.

With the coming of the [[muscle car]], and beyond that to the high-performance luxury car, customization declined. One place where it persisted was the US Southwest, where "[[low-rider]]s" were built similar in concept to the earlier customs, but of post-1950s cars.

===Recent trend to build new custom steel bodies based on pre-war designs===
Recently, as the supply of usable antique steel bodies has given out, a new trend to fabricate new steel bodies, closely based on the styling of the pre-war cars. Bodies of this type can cost over $100,000 before the "running gear" is added.

<gallery>
Image:Modern "basic" Hot Rod.jpg|Modern, but very Basic '32 roadster {{3d_glasses}}
Image:1951 Mercury.jpg|Recent custom job on a '51 Mercury {{3d_glasses}}
Image:1940 Ford.jpg|thumb|250px|Modern Custom {{3d_glasses}}
</gallery>

===See also===
{{commonscat|Custom cars}}
* [[my dream wheels]]
* [[Go-faster stripes]]
* [[Hot rod]]
* [[Kustom Kulture]]
* [[Lowrider]]
* [[Import scene]]
* [[Pimp My Ride]]
* [[PFS Imports]]

== External links ==

* [http://www.customcarsuk.com/ U.K. free site for custom cars]
* [http://www.mydreamwheels.com/ Custom Cars, hot rods, vintage cars]
* [http://www.roddingroundtable.com/ The Rodding Roundtable]
* [http://www.justcustomz.com/gallery/hotrod-pictures.php More Custom Car Pictures]
* [http://www.american-excess.com CAR SHOWS IN BELGIUM ]

[[category:automotive technologies]]
[[Category:Vehicle modification]]
[[Category:DIY Culture]]
[[de:Custom car]]
[[sv:Custom]]

Cruise control

2006-06-28T21:47:26Z

Philip rosenblum:

{{For|the software build framework|CruiseControl}}

[[Image:2000 Jeep Steering Wheel.jpg|thumb|250px|Cruise Control Controls on a 2000 Jeep Grand Cherokee Steering Wheel]]

'''Cruise control''' (sometimes known as '''speed control''' or '''Autocruise''') is a system to automatically control the [[speed]] of an [[automobile]]. The driver sets the speed and the system will take over the throttle of the car to maintain the same speed.

==History==
Speed control with a [[centrifugal governor]] was used in automobiles as early as the [[1910s]], notably by [[Peerless]]. Peerless advertised that their system would "maintain speed whether up hill or down". The technology was invented by [[James Watt]] and [[Matthew Boulton]] in [[1788]] for use in [[locomotive]]s. It uses [[centrifugal force]] to adjust throttle position as the speed of the engine changes with different loads (e.g. when going up a hill).

Modern cruise control was invented in [[1945]] by the blind inventor and mechanical engineer [[Ralph Teetor]]. His idea was born out of the frustration of riding in a car driven by his lawyer, who kept speeding up and slowing down as he talked. The first car with Teetor's system was the [[Chrysler Corporation]] [[Chrysler Imperial|Imperial]] in [[1958]]. This system calculated ground speed based on [[driveshaft]] rotations and used a [[solenoid]] to vary throttle position as needed.

==Theory of operation==
In modern designs, the cruise control may or may not need to be turned on before use — in some designs it is always "on" but not always enabled, others have a separate "on/off" switch, while still others just have an "on" switch that must be pressed after the vehicle has been started. Most designs have buttons for "set", "resume", "accelerate", and "coast" functions. Some also have a "cancel" button. Or simply tapping the brake on most cars equipped with cruise control will disable it. The system is operated with controls easily within the driver's reach, usually with two or more buttons on the [[steering wheel]] or on the [[turn signal]] stalk.

The driver must bring the car up to speed manually and use a button to set the cruise control to the current speed. The cruise control takes its speed signal from a rotating [[driveshaft]], [[speedometer]] cable or from the engine's [[RPM]]. Most systems do not allow the use of the cruise control below a certain speed (normally 35 mph/55 km/h) to discourage use in city driving. The car will maintain that speed by pulling the [[throttle]] cable with a solenoid or a [[vacuum]] driven [[servomechanism]]. On the latest vehicles fitted with [[electronic throttle control]], cruise control can be easily integrated into the vehicle's engine management system. Most systems can be turned off both explicitly and automatically, when the driver hits the [[brake]] or [[clutch]]. Cruise control often includes a memory feature to resume the set speed after braking and a coast feature to reset the speed lower without braking. When the cruise control is in effect, the throttle can still be used to accelerate the car, but once it is released the car will then slow down until it reaches the previously set speed.

==Advantages and disadvantages==
Cruise control has many advantages but also some serious vices.

Some of those advantages include:
* Its usefulness for long drives across sparsely populated [[road]]s. This usually results in better fuel efficiency.
* Some drivers use it to avoid unconciously violating speed limits. A driver who otherwise tends to unconsciously increase speed over the course of a highway journey may avoid a speeding ticket. Such drivers should note, however, that a cruise control may go over its setting on a downhill which is steep enough to accelerate with an idling engine.

However, cruise control can also lead to accidents due to several factors, such as:
* The lack of need to maintain constant pedal pressure, which can help lead to accidents caused by [[highway hypnosis]] or incapacitated drivers; future systems may include a [[penalty switch]] to avoid this.
* When used during inclement weather or while driving on wet or snow- and/or ice-covered roads, the vehicle could go into a skid. Stepping on the brake – such as to disengage the cruise control – often results in the driver losing control of the vehicle.

Many countries establish that it is illegal to drive within city limits with the cruise control feature activated.

==Autonomous cruise control system==
Some modern vehicles have '''autonomous cruise control (ACC)''' systems. These use either a [[radar]] or [[laser]] setup to allow the vehicle to slow when approaching another vehicle and accelerate again to the preset speed when traffic allows. Some systems also allow the driver to choose a preset headway or following distance. [[Mercedes-Benz]] was the first to offer such a system, under the ''Distronic'' name, but similar adaptive systems are now offered by other manufacturers. For [[2006]], Mercedes-Benz refined the Distronic system to completely halt the car if necessary (now called 'Distronic Plus'), a feature not offered by any other implementation.

[[Toyota Motor Corporation|Toyota]]'s [[Lexus]] vehicles were second to market with "DLCC" (Dynamic Laser Cruise Control). [[Volkswagen]] will bring the technology to the mainstream with their [[2006]] [[VW Passat|Passat]]. Other vehicles with adaptive cruise control include the [[Acura RL]], [[Audi A6]], [[Audi A8]], [[BMW 3 Series]] (called Active Cruise Control), [[BMW 5 Series]], [[BMW 7 Series]], [[Cadillac STS]], [[Cadillac XLR]], [[Infiniti M]], [[Infiniti Q45]], [[Jaguar XK8|Jaguar XK-R]], Jaguar S, [[Lexus LS|Lexus LS430/460]], [[Lexus ES|Lexus ES-350]], [[Nissan Primera]] T-Spec Models (called Intelligent Cruise Control), [[Mercedes-Benz S-Class]], E55 AMG, CLS, SL, CL, [[Toyota Sienna]] XLE (limited availability), and [[Volkswagen Phaeton]].

[[General Motors Corporation|General Motors]] [[Cadillac]] division now offers Adaptive Control on the [[DTS]] series of its luxury vehicles. This is most notable by sensors mounted on the front bumper of the DTS. One must look closely because they are seamlessly integrated into the front of the vehicle. The 2007 [[Volvo S80]] will have such a system.

== References ==
# {{cite press release
|publisher = University of Michigan
|date = July 12, 2004
|title = U-M physicist: Smart cruise control eliminates traffic jams
|url= http://www.umich.edu/news/index.html?Releases/2004/Jul04/r071204
}}
# {{cite journal
|author= L. C. Davis
|title= Effect of adaptive cruise control systems on traffic flow
|journal= Physical Review Letters E
|year= 2004
|volume= 69
|issue= 6
|pages= 066110 (article ID; no page reference)
|url= http://link.aps.org/abstract/PRE/[[V6|v6]]9/e066110
}}
# {{cite journal
|author= CY Liang, H Peng
|title= Optimal Adaptive Cruise Control with Guaranteed String Stability
|journal= Vehicle System Dynamics
|year= 1999
|volume= 32
|issue= 4-5
|pages= 313-330 |url= http://www-personal.engin.umich.edu/~hpeng/VSD_1999_Liang.pdf
}}
# {{cite journal
|author= P Venhovens, K Naab, B Adiprasito
|title= Stop and Go Cruise Control
|journal= Proc. FISITA World Automotive Congress, Seoul, Korea
|year= 2000
|url= http://society.kisti.re.kr/~Eksae/_notes/data/pdf/v1n2_1.pdf
}}
# {{cite journal
|author= C M Rudin-Brown, H A Parker
|title= Behavioural adaptation to adaptive cruise control (ACC): Implications for preventive strategies
|journal= Transportation Research Part F: Traffic Psychology and Behaviour
|year= 2004
|volume= 7
|issue= 2
|pages= 59-76
}}
# {{cite journal
|author= N A Stanton, M S Young
|title= Driver behaviour with adaptive cruise control
|journal= Ergonomics
|year= 2005
|volume= 48
|issue= 10
|pages= 1294-1313
}}

==External links==
*[http://www.esafetysupport.org/en/learn_about_esafety_systems/ Overview of intelligent vehicle safety systems]
*[http://www.ertico.com/ Intelligent Transport Systems]
*[http://prevent-ip.org/en/ Preventive safety applications and technologies]
*[http://auto.howstuffworks.com/cruise-control.htm Article at] [[HowStuffWorks]]
* [http://www.snopes.com/autos/techno/cruise.asp Cruise [Un]Control: Driver sets the cruise control on his vehicle, then slips into the backseat for a nap. (Snopes.com)]

[[Category:Automotive accessories]]
[[Category:Automotive technologies]]

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File:Breakerpoints.jpg

2006-06-28T21:46:04Z

Philip rosenblum:

Contact breaker

2006-06-28T21:45:29Z

Philip rosenblum:

[[Image:breakerpoints.jpg|thumb|right|250px|Breaker arm with contact points at the left. The pivot is on the right and the cam follower is in the middle of the breaker arm.]]
A '''contact breaker''' (or "points") is a type of electrical [[switch]], and the term typically refers to the switching device found in the [[distributor]] of the [[ignition system]]s of spark-ignition [[internal combustion engine]]s.

== Purpose ==

The purpose of the contact breaker is to interrupt the [[current (electricity)|current]] flowing in the primary circuit of the [[ignition coil]]. When this occurs, the collapsing current [[Electromagnetic induction|induces]] a high voltage in the secondary winding of the coil, which has very many more turns. This causes a very large [[voltage]] to appear at the coil output for a short period - enough to arc across the electrodes of a [[spark plug]].

== Operation ==
The contact breaker is operated by an engine-driven [[cam]], and the position of the contact breaker is set so that they open (and hence generate a spark) at the exactly correct moment needed to ignite the fuel at the top of the piston's compression stroke. The contact breaker is usually mounted on a plate that is able to rotate relative to the [[camshaft]] operating it. The plate is rotated by a centrifugal mechanism, thus advancing the [[timing]] (making the spark occur earlier) at higher revolutions. This gives the fuel time to burn so that the resulting gases reach their maximum pressure at the same time as the piston reaches the top of the [[Cylinder (engine)|cylinder]]. The plate's position can also be moved a small distance using a small [[vacuum]]-operated [[servomechanism]], providing advanced timing when the engine is required to speed up on demand. This helps to prevent [[engine knocking|pre-ignition]] (or [[pinging]]).

== Disadvantages of contact breakers ==
Since they open and close several times every turn of the engine, contact breaker points and cam follower suffer from wear - both mechanical and pitting caused by arcing across the contacts. This latter effect is largely prevented by placing a [[capacitor]] [[Series and parallel circuits|parallel]] across the contact breaker - this is usually referred to by the more old fashioned term [[condenser]] by mechanics. As well as suppressing arcing, it helps boost the coil output by creating a resonant [[LC circuit]] with the coil windings. A drawback of using a mechanical switch as part of the ignition timing is that it is not very precise, needs regular adjustment of the [[dwell]] (contact) angle, and at higher revolutions, its mass becomes significant, leading to poor operation at higher engine speeds. These effects can largely be overcome using electronic ignition systems, where the contact breakers are [[retro]]fitted by a massless [[sensor]] device.

[[Category:Automotive technologies]]

[[fr:Rupteur]]
[[ru:Прерыватель (система зажигания)]]

Cold air intake

2006-06-28T21:44:19Z

Philip rosenblum:

A '''cold air intake''' is a [[system]] used to bring down the [[temperature]] of the [[air]] going into a [[Automobile|car]] for the purpose of increasing the <nowiki>power</nowiki> of the [[internal-combustion engine]]. A secondary goal is to increase the appeal of a car by changing the appearance of a car's engine bay and creating an attractive intake [[noise (environmental)|noise]]. These [[Aftermarket (automotive)|aftermarket]] parts come in many different colors and many different sizes, and are an inexpensive way to increase performance.

Aftermarket company, K&N Engineering first offered air intake systems in the late 1980s. Those intakes consisted of rotationally-molded plastic intake tubes and a conical, cotton gauze air filter. In the late 1990s a proliferation of intake manufacturers such as AEM, Airaid and Volant entered the fray. In addition, oversea manufacturers imported their designs lending to the popularity of Japan domestic market ([[JDM]]) air intakes in sport compact markets. K&N and many of the other intake companies now offer intake systems in metal tube designs, allowing a greater degree of customization (the tubes can be powder-coated or painted to match a vehicle).

All cold air intakes operate on the principal of increasing the amount of [[oxygen]] available for [[combustion]] with [[fuel]]. Because cooler air has more density for a given volume, cold air intakes generally work by providing cooler air from outside the hot engine bay. However, the term "cold air intake" is often used to describe other methods of increasing oxygen to an engine, which may even increase the temperature of the air coming into an engine.

Some strategies used in designing cold-air intakes are:
*increasing the diameter of the air intake, allowing increased airflow.
*smoothing the interior of the intake to reduce air resistance.
*providing a more direct route to the air intake.
*tuning the length of the intake to provide the most airflow at certain RPMs.
*using a more efficient [[air filter]]

Intake systems come in many different styles and can be constructed from plastic, metal, rubber (silicone) or composite materials (fiberglass, carbon fiber or kevlar). Due to the limited time air actually remains inside the intake tubing, the materials often do not impact a kit's ability to deliver cool air.

The most basic cold air intake replaces the stock airbox with a short metal or plastic tube leading to a conical air filter, called a [[Short ram air intake]]. The power gained by this method can vary depending on how restrictive the factory airbox is. The placement of the filter is usually directly in the engine compartment. The overall benefits depend on the specific application. Power may be lost at certain engine speeds, only to be gained at others. Because of the increased airflow and reduced covering, intake noise is usually increased. This effect is usually amplified on applications where a resonator, a part intended to reduce intake noise on some vehicles is replaced by the intake.

Better designed intakes use heat shields to isolate the air filter from the rest of the engine compartment, providing cooler air from the front or side of the engine bay. [[Graphite-reinforced_plastic|Carbon fiber]] can be used for the piping instead of metal, lowering weight and insulating the air from the engine bay in some cases. Carbon fiber and other advanced composites (such as Kevlar) come at significant costs and are often more aesthetic rather than functional (unless the application is a serious race vehicle).

The most extreme designs, sometimes referred to as Complete Cold Air (CCA) intakes, route air from outside the engine bay, usually from the wheel wells, front grill, or a hood scoop. The intake can be placed such that the forward motion of the car pressurises the air coming in, creating a [[ram-air intake]]. These intakes often require additional modifications and can require body modifications or replacement panels, such as a replacement "ram air-style" hood.

The best cold-air intakes are optimized for a specific engine application, providing increased airflow at ambient temperature and raising power at all engine speeds.

When using a cold air intake, there is a potential risk when driving in the rain. This is often referred to as "hydrolock", and according to the automotive portal, [http://www.modsearch.com/article-cold_air_intake.html MODsearch]: "Say it's raining cats and dogs and you're out for a spin in your car. Normally you'd love to rip through puddles without thinking twice, but because your engine is now getting air from inside your bumper you have to be careful. If your engine manages to suck up any amount of water through the intake and into the engine you will probably have little to no [[HP|horsepower]] left. In other words, be careful." So, it is important to take the necessary precautions when using a cold air intake so you do not end up flooding your engine. This may include installing a water shield in your intake or not driving in the rain at all. It is also notable that less damage will occur from water getting in the engine on a rotary engine car, as opposed to a piston engine car.

==See also==
* [[Supercharger]]
* [[Turbocharger]]
* [[Warm air intake]]

[[Category:Automotive technologies]]
[[Category:Engine technology]]
[[Category:Vehicle modification]]

Choke valve

2006-06-28T21:43:22Z

Philip rosenblum:

A '''choke valve''' is sometimes installed in the [[carburetor]] of [[internal combustion engine]]s. Its purpose is to restrict the flow of [[air]] into so as to enrich the [[air-fuel ratio|fuel-air mixture]] while starting the engine. Depending on engine design and application, the valve can be activated manually by the operator of the engine (via a [[lever]] or [[pull handle]]) or automatically by a [[temperature]]-sensitive mechanism.

Choke valves are important for carbureted [[gasoline]] engines because small droplets of gasoline do not evaporate well within a cold engine. By restricting the flow of air into the carburetor, the choke valve causes more vacuum inside the carburetor and hence a greater amount of fuel to be sucked into the engine compared to normal operation. Once the engine is warm (from [[combustion]]), opening the choke valve restores the carburetor to normal operation, supplying fuel and air in the correct [[stoichometry|stoichiometric]] ratio for clean, efficient combustion.

Chokes were nearly universal in [[automobiles]] until [[fuel injection]] replaced carburetion in the late 1980s. Choke valves are still extremely common in other internal-combustion applications, including most small portable engines, [[motorcycle]]s, small prop-powered [[fixed-wing aircraft|airplane]]s, and carbureted marine engines.

[[Category:Automotive technologies]]

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{{auto-part-stub}}

Catalytic converter

2006-06-28T21:42:18Z

Philip rosenblum:

A '''catalytic converter''' (colloquially, "cat" or "catcon") is a device used to reduce the toxicity of emissions from an internal combustion engine. First widely introduced on [[Mass_production|series-production]] automobiles in the [[USA|US]] market for the [[1975]] [[model year]] to comply with tightening [[Environmental_Protection_Agency|EPA]] regulations on auto exhaust, catalytic converters are still most commonly used in [[automobile|motor vehicle]] [[exhaust gas|exhaust]] systems. Catalytic converters are also used on [[generator]] sets, [[forklift]]s, mining equipment, [[truck]]s, [[bus]]es, [[train]]s, and other engine-equipped machines. A catalytic converter provides an environment for a [[chemical reaction]] wherein toxic combustion byproducts are converted to less-toxic gases. The catalytic converter was invented at [[Trinity College (Connecticut)]].

==Purpose and function of catalytic converters ==
*A three-way catalytic converter has three simultaneous tasks:
# [[Reduction]] of [[nitrogen oxides]] to [[nitrogen]] and [[oxygen]]: 2NOx → xO2 + N2
# [[Oxidation]] of [[carbon monoxide]] to [[carbon dioxide]]: 2CO + O2 → 2CO2
# Oxidation of unburnt [[hydrocarbons]] (HC) to carbon dioxide and [[water]]: CxHy + nO2 → xCO2 + mH2O

These three reactions occur most efficiently when the catalytic converter receives exhaust from an engine running at the [[stoichiometric]] point. This is 14.7 parts Oxygen to 1 part fuel for gasoline (the ratio for [[Propane]], [[Natural Gas]], and [[Ethanol]] fuels is slightly different, requiring modified fuel system settings when using those fuels). When there is more oxygen than required, then the system is said to be running lean, and the system is in oxidizing condition. In that case, the converter's two oxidizing reactions (oxidation of CO and hydrocarbons) are favoured, at the expense of the reducing reaction. When there is excessive fuel, then the engine is running rich. The reduction of NOx is favoured, at the expense of CO and HC oxidation. If an engine could be held at the strict stoichiometric point for the fuel used, it is theoretically possible to reach 100% conversion efficiencies.

Since 1981, three-way catalytic converters have been at the heart of vehicle emission control systems in North American roadgoing vehicles, and are also used on "Large [[spark plug|Spark]] [[ignition system|Ignition]]" engines. LSI engines are used in [[forklift]]s, aerial boom lifts, ice resurfacing machines, and construction equipment. The converters used in these are three-way types designed to reduce combined NOx+HC [[automobile emissions control|emission]]s from 12 [[gram]]/[[horsepower#Brake horsepower (bhp)|BHP]]-hour to 3 gram/BHP-hour or less, per the [[Environmental Protection Agency]] (EPA) 2004 regulations. A further drop to 2 gram/BHP-hour of NOx+HC emissions is mandated in 2007 (note: NOx is the industry standard short form for [[nitric oxide]] (NO) and [[nitrogen dioxide]] (NO2) both of which are smog precursors. HC is the industry short form for hydrocarbons).

*A two-way catalytic converter has two simultaneous tasks:
# [[Oxidation]] of [[carbon monoxide]] to [[carbon dioxide]]: 2CO + O2 → 2CO2
# Oxidation of unburnt hydrocarbons (unburnt and partially-burnt fuel) to carbon dioxide and [[water]]: CxHy + O2 → xCO2 + mH2O

This type of catalytic converter is commonly used on [[diesel]] engines to reduce [[hydrocarbon]] and [[carbon monoxide]] emissions. They also were used on spark ignition ([[gasoline]]) engines in automobiles up until 1981, when they were replaced by three-way converters due to regulatory changes requiring reductions on [[NOx]] emissions.

Curiously the regulations regarding [[Hydrocarbons]] vary according to the engine regulated, as well as the jurisdiction. In some cases what is regulated is "Non-Methane [[Hydrocarbons]]", and in other cases the regulated substance is "Total [[Hydrocarbons]]". Technology for one application (to meet a Non-Methane Hydrocarbon standard) may not be suitable for use in an application that has to meet a Total Hydrocarbon standard. [[Methane]] [[Hydrocarbons]] are more difficult to break down in a catalytic converter, so in effect a "Non-Methane Hydrocarbon" standard can be considered to be looser. However since Methane is a [[Global Warming]] gas, more interest is rising in how to eliminate emissions of it.

==Catalyst poisoning==
Catalytic converters become ineffective in the presence of [[lead]] due to [[catalyst]] poisoning, and the introduction of catalytic converters triggered the end of [[tetra-ethyl lead|leaded gasoline]]. [[Catalyst]] poisoning occurs when a substance in the engine exhaust coats the surface of the catalyst, preventing further exhaust access to the catalytic materials. Poisoning can sometimes be reversed by running the engine under a very heavy load for an extended period of time to raise exhaust gas temperature, which may cause liquefaction or sublimation of the catalyst poison. Common catalyst poisons are [[lead]], [[sulfur]], [[zinc]], [[manganese]], [[silicone]], and [[phosphorus]]; Zn, P, and S originate from [[lubricant]] [[AW additive|antiwear additives]] such as [[ZDDP]]; sulfur and manganese primarily originate from fuel impurities or [[Methylcyclopentadienyl_Manganese_Tricarbonyl|additives]], respectively. [[Silicone]] poisoning is usually the result of engine damage, such as a faulty cylinder head gasket or cracked casting, admitting silicate-containing [[Antifreeze_(engine)|coolant]] into the combustion chamber. Removal of [[sulfur]] from a catalyst surface by running heated exhaust gasses over the catalyst surface is often successful, however removal of [[lead]] deposits is often not possible (the lead becomes vapourised in the combustion chamber of a gasoline 4 stroke engine under the ambient temperature and pressure after charge air ignition, and condenses on the cooler catalytic converter core surface. In particularly bad cases of catalyst poisoning by Lead the converter can actually become completely plugged with lead residue). Theoretically, catalyst poisoning could also occur if the charge air was contaminated by a catalyst poison, however catalyst poisons are all substances that are solid at the internal temperature of the catalytic converter, and thus precipitate out of the air.

Any condition that increases the concentration of CO or HC reaching the catalyst can cause it to overheat and melt down, restricting the exhaust flow, rendering the converter useless for emission control purposes, and creating an undercar fire hazard. Some such conditions are oil-burning engines, overly rich fuel mixtures, and misfires.

==Technical details==
The catalytic converter consists of several components:
# The core, or substrate. In modern catalytic converters, this is most often a [[ceramic]] honeycomb, however [[stainless steel]] foil honeycombs are also used. The purpose of the core is to "support the catalyst", and therefore it is often called a "Catalyst Support".
# The washcoat. In an effort to make converters more efficient, a washcoat is utilized, most often a mixture of [[silicon]] and [[aluminum]]. The washcoat, when added to the core, forms a rough, irregular surface which has a far greater surface area than the flat core surfaces, which is desirable to give the converter core a larger surface area, and therefore more places for active precious metal sites. The catalyst is added to the washcoat (in suspension) before application to the core.
# The catalyst itself, most often a precious metal. [[Platinum]] is the most active catalyst, and is widely used. However, it is not suitable for all applications because of unwanted additional reactions and/or cost. [[Palladium]] and [[rhodium]] are two other precious metals that are used, Palladium as a substitute for Platinum in three-way catalytic converters, and Rhodium is the material that makes a three-way reaction possible. [[Cerium]], [[iron]], and [[nickel]] are also used, though each has its own limitations. Nickel is not legal for use in the European Union (nickel hydrate formation). While [[copper]] can be used, its use is illegal in North America due to the formation of [[dioxin]].

===Gasoline Engines===
Catalytic converters are used on spark ignition ([[gasoline]]; [[liquified petroleum gas]] (LPG); [[flexible fuel vehicle]]s burning varying blends of [[E85]] and gasoline; [[compressed natural gas]] (CNG)) engines; and compression ignition ([[diesel]]) engines. The reasons for use on each type of engine are different.

For spark ignition engines the most commonly used catalytic converter is the three-way converter, which should only be used on engines equipped with [[closed-loop controller|closed-loop feedback]] fuel mixture control employing an [[Oxygen sensor#Automotive applications|Oxygen sensor]]. Practically, this means either [[fuel injection]] or a [[carburetor]] equipped for feedback mixture control. This is because the three-way converter works best when the air-fuel ratio of the engine is kept within a certain very narrow range of the 14.7:1 Oxygen:fuel stoichiometry point. Within that band, conversions are very high, sometimes approaching the theoretical point of perfection (i.e. 100%), however, outside of that band, conversions tend to fall off very rapidly (see [[Bell Curve]]). There are also two-way converters available that were used in early carburetored cars.

A three-way catalyst reduces emissions of CO ([[Carbon Monoxide]]), HC ([[hydrocarbon]]s), and NOx (nitrogen oxides) simultaneously when the oxygen level of the exhaust gas stream is below 1.0%, though performance is best at below 0.5% O2. Unwanted reactions can occur in the three-way catalyst such as the formation of H2S ([[hydrogen sulfide]]) and NH3 ([[ammonia]]). Formation of each can be limited by modifications to the washcoat/precious metals used, however are difficult to eliminate completely.

For example when control of H2S emissions are desired, Nickel or Manganese is added to the washcoat - both substances act to block the adsorbtion of sulfur by the washcoat (H2S is formed when the washcoat has adsorbed Sulfur during a low temperature part of the operating cycle, which is then released during the high temperature part of the cycle and the S2 combines with HC). For "lean burn" spark ignition engines (e.g. compressed natural gas, or compressed natural gas with diesel fuel pilot injection), an oxidation catalyst is used in the same manner as in a compression ignition engine.

Early three-way catalytic converters utilized an air tube between the first part of the converter (the NOx part) and the second part, which is virtually unchanged from earlier two-way catalytic converters. This tube was fed by either an air pump (derived from the earlier [[Air_injection_reactor|A.I.R.]] systems) or by a [[Pulse Air]] system. The extra oxygen was used to offset the less precise control of earlier systems by providing the oxygen for the catalyst's oxidizing reaction. The first section was still prone to difficulties on lean conditions with too much oxygen for the NOx reduction to be complete, but the second section always had oxygen available. These systems also commonly included an upstream air injector, either a modified A.I.R. system or another opening in the manifold, to add oxygen into the system to burn the extra-rich mixture used in a cold engine and to allow the additional burning to happen as close to the converter as possible to heat it up to operating temperature quickly.

Newer systems use several techniques to avoid the air tubes. They provide a constantly varying mixture that quickly cycles lean and rich mixtures to keep the first catalyst (NOx) from becoming oxygen loaded and the second catalyst sufficiently oxidized, which is less of a concern due to the oxygen created in the first section. They also utilize several oxygen sensors to monitor the exhaust, at least one before the catalytic converter for each bank of cylinders, and one after the converter. Newer systems also often have several units mounted along the pipe to provide different functions rather then one monolithic system.

Recently, systems have used a separate early catalytic converter in the system to reduce startup emissions and burn off the hydrocarbons from the extra-rich mixture used in a cold engine. Also, the other parts are now often separated in the system to provide optimum temperature and provide space for extra oxygen sensors.

===Diesel Engines===
For compression ignition (i.e., [[Diesel]]) engines, the most commonly used catalytic converter is the diesel oxidation catalyst. The catalyst uses excess O2 (oxygen) in the exhaust gas stream to oxidize CO (Carbon Monoxide) to CO2 (Carbon Dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often reach 90% effectiveness, virtually eliminating diesel odor and helping to reduce visible [[particulate]]s ([[soot]]), however they are incapable of reducing NOx as chemical reactions always occur in the simplest possible way, and the existing O2 in the exhaust gas stream would react first.

To reduce NOx on a compression ignition engine it is necessary to change the exhaust gas - two main technologies are used for this - [[selective catalytic reduction]] (SCR) and NOx (NOx) traps (or [[NOx Adsorbers]]).

Another issue for diesel engines is particulate (soot). This can be controlled by a soot trap or [[Diesel Particulate Filter]] (DPF), as catalytic converters are unable to affect elemental carbon (however they will remove up to 90% of the soluble organic fraction). However, DPFs can clog and lose their effectiveness with time and use.

===Oxygen storage===
In order to oxidize CO and HC, the catalytic converter also has the capability of storing the Oxygen from the exhaust gas steam, usually when the air fuel ratio goes lean. When insufficient Oxygen is available from the exhaust stream the stored Oxygen is released and consumed. This happens either when oxygen derived from NOx reduction is unavailable or certain maneuvers such as hard acceleration enrich the mixture beyond the ability of the converter to compensate.

==Regulations==
Emissions regulations vary considerably from jurisdiction to jurisdiction, as do what engines are regulated. In [[North America]] any spark ignition engine of over 19 [[Watt|kW]] (25 [[horsepower|hp]]) power output built later than [[January 1]], [[2004]] probably has a three-way catalytic converter installed. In [[Japan]] a similar set of regulations will come into effect [[January 1]], [[2007]], while the [[European Union]] has not yet enacted analogous regulations. Most all automobile spark ignition engines in North America have been fitted with catalytic converters since the mid-[[1970s]], and the technology being used in non-automotive applications is generally based on automotive technology.

Diesel engine regulations are similarly varied, with some jurisdictions focusing on NOx (Nitric Oxide and Nitrogen Dioxide) emissions and others focusing on particulate (soot) emissions. This can cause problems for the engine manufacturers as it may not be economical to design an engine to meet two sets of regulations.

Another issue is that fuel quality varies widely from place to place, as do the regulations covering fuel quality. In North America both gasoline and diesel fuel are highly regulated, and there are campaigns under way to regulate CNG and LPG as well. In most of Asia this is not true - in some places [[sulfur]] content of the fuel can reach 20,000 parts per million (2 %). Any sulfur in the fuel may be oxidized to SO2 ([[sulfur dioxide]]) or even SO3 ([[Sulfur trioxide]]) in the combustion chamber. If sulfur passes over a catalyst it may be further oxidized in the catalyst, i.e. (SO2 may be further oxized to SO3). Sulfur oxides are precursors to [[sulfuric acid]], a major component of [[acid rain]]. While it is possible to add substances like [[Vanadium]] to the catalyst wash coat to combat sulfur oxide formation, this will reduce the effectiveness of the catalyst—the best solution is further refinement of the fuel at the refinery to remove the Sulfur. Regulations in Japan, Europe and—by 2007—North America tightly restrict the amount of Sulfur permitted in motor fuels. However, the expense is such that this is not practical in many developing countries. As a result cities in these countries with high levels of vehicular traffic suffer damage to buildings due to acid rain eating away the stone/woodwork, and acid rain has deleterious effects on the local ecosystem.

===Regulatory agencies===
The agencies charged with regulating engine emissions vary from jursidiction to jurisdiction, even in the same country. For example in the [[United States]] overall responsibility belongs to the [[United_States_Environmental_Protection_Agency|Environmental Protection Agency]], however due to the special requirements of the [[State of California]] emissions in California are regulated by the [[California Air Resources Board|Air Resources Board]], and in Texas the [[Texas Railroad Commission]] is responsible for regulating emissions from LPG fueled rich burn engines (but not gasoline fueled rich burn engines).

*[[California Air Resources Board|Air Resources Board]] - California, United States (most sources)
*[[Environment Canada]] - Canada (most sources)
*[[United_States_Environmental_Protection_Agency|Environmental Protection Agency]] - United States (most sources)
*[[Texas Railroad Commission]] - Texas, United States (LPG fueled engines only)
*[[Transport Canada]] - Canada (trains and ships)

==Diagnostics==
Various jurisdictions now legislate on-board diagnostics to monitor the effectiveness of the emissions control system, including the catalytic converter, and such diagnostics are often included in aftermarket retrofit kits as a matter of course, even if legislation does not directly require them.

On-board diagnostics take several forms, depending upon the legislation and the type of emissions control product being monitored, the three main types are

* Temperature Sensor
* Oxygen Sensor
* NOx Sensor

===Temperature sensors===
Temperature sensors are used for two purposes. The first is as a warning system, typically on obsolete 2-Way catalytic converters such as are still sometimes to LPG forklifts. The function of the sensor is to warn of temperature excursions above the safe operating temperature of the 2-Way catalytic converter of 750 Degrees Celsius. Note that modern catalytic converters are not as susceptible to temperature damage, many modern 3-Way Platinum based converters can handle temperatures of 900 Degrees Celsius sustained, while many modern 3-Way Palladium based converters can handle temperatures of 925 Degrees Celsius sustained. Temperature sensors are also used to monitor catalyst functioning - usually two sensors will be fitted, one before the catalyst, and one after to monitor the temperature rise over the catalytic converter core. For every 1% of CO in the exhaust gas stream the exhaust gas temperature will rise by 100 Degrees Celsius.

===Oxygen sensors===
The [[Oxygen_sensor#Automotive_applications|Oxygen sensor]] is the basis of the Closed Loop Control system on a spark ignited rich burn engine, however it is also used for diagnostics. Oxygen sensors only work when at operating temperature, when they output a voltage based on the O2 level in the exhaust gas to the computer. Typically a single wire oxygen sensor will take 3-5 minutes to reach operating temperature. The more expensive heated sensors (3 to 5 wires) can reach operating temperature in 1 minute.

The simplest sort of diagnostic an oxygen sensor can perform is related to the closed loop control system. If the system makes a change to the air-fuel ratio based on oxygen sensor readings, and the readings do not change the sensor will light an indicator on the instrument panel warning the operator that there is a problem with the vehicle. There is always a delay before this happens, usually 5 minutes of engine operation. Most systems do not store the state, so turning off the engine and turning it back on will reset the system, and if the error is transient (i.e. fuel filter is partially blocked) the light will not come back on, however if the problem is recurring the light will come on as soon as the sensor reaches operating temperature. Such diagnostics have been factory fitted to automobiles since 1985 in North America, and factory fitted to off-road Spark Ignition engines since 2004 (however such systems have been available as retrofit kits for off-road SI engines since 1997).

The second sort of diagnostic is more complex, and is a result of the California OBD 2 rule (though temperature sensors are sometimes used for this). For OBD 2 a second oxygen sensor is fitted after the catalytic converter, and this sensor monitors the O2 levels, and the on-board computer makes comparisons to the readings of the two sensors. If both sensors give the same output, the catalytic converter is non-functioning, and must be replaced. It will also spot less serious damage to a catalytic converter, such as the use of racing fuel in an on-road vehicle. Lead is still legal in racing fuel, and use of as little as half a tank of leaded fuel will cause enough damage for the computer to notice, and warn the operator that the converter is not functioning properly.

===NOx sensors===
NOx sensors are extremely expensive, and are generally only used when a compression ignition engine is fitted with a Selective Catalytic Reduction Converter, or a NOx Adsorber Catalyst in a feedback system (though many SCR systems do not use a NOx sensor, but instead rely on the engine map being programmed into the Engine Control Unit or computer). When fitted to an SCR system there may be one or two sensors. When one sensor is fitted it will be pre-catalyst, when two are fitted the second one is post catalyst. They are utilized for the same reasons, and in the same manner as an Oxygen Sensor - the only difference is the substance being monitored.

==See also==
*[[Automobile emissions control]]
*[[DPF]]
*[[Selective_Catalytic_Reduction|SCR]]
*[[NOx Adsorbers]]
*[[Roadway air dispersion modeling]]

==Patents==
* Keith, C. D., et al., -- {{US patent|3441381}} -- "''Apparatus for purifying exhaust gases of an internal combustion engine" -- April 29, 1969

[[Category:Automotive technologies]]
[[Category:Automotive accessories]]
[[Category:Pollution control technologies]]

[[de:Fahrzeugkatalysator]]
[[he:ממיר קטליטי]]
[[ja:三元触媒]]
[[fi:Katalysaattori]]
[[tr:Katalitik konvertör]]

Caster angle

2006-06-28T21:41:18Z

Philip rosenblum:

[[image:caster_angle.png|thumb|300px|right|θ is the caster angle, red line is the pivot line, grey area is the tire]]
'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)|suspension]] of a steered [[wheel]] in a [[Automobile|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.

The pivot points of the [[steering]] are angled such that a line drawn through them intersects the road surface slightly ahead of the contact point of the wheel. The purpose of this is to provide a degree of self-centering for the steering - the wheel casters around so as to trail behind the axis of steering. This makes a car easier to drive and improves its straight line [[stability]] (reducing its tendency to wander). Excessive caster angle will make the steering heavier and less responsive, although, in racing, large caster angles are used to improve camber gain in cornering. Caster angles over 10 degrees with radial tires are common. Power steering is usually necessary to overcome the jacking effect from the high caster angle.

The steering axis (the dotted line in the diagram above) does not have to pass through the center of the wheel, so the caster can be set independently of the mechanical trail, which is the distance between where the steering axis hits the ground, in side view, and the point directly below the axle. The interaction between caster angle and trail is complex, but roughly speaking they both aid steering, caster tends to add damping, while trail adds 'feel', and returnability. In the extreme case of the shopping trolley (shopping cart in the US) wheel, the system is undamped but stable, as the wheel oscillates around the 'correct' path. The shopping trolley/cart setup has a great deal of trail, but no caster. Complicating this still further is that the lateral forces at the tire do not act at the center of the contact patch, but at a distance behind the nominal contact patch. This distance is called the pneumatic trail and varies with speed, load, steer angle, surface, tire type, tire pressure and time. A good starting point for this is 30 mm behind the nominal contact patch.

== History ==
[[Arthur Krebs]] applied the first the positive caster angle to automotive front-train in his [http://en.wikipedia.org/wiki/Image:Krebs_Boulogne_M_et_Mme_K_Auto_ACK_7_1896.jpg 1896 car] English patent : "To ensure stability of direction by means of a special arrangement of fore-carriage, that is to say, to re-establish automatically the parallelism of the two axles of the vehicle when there is no tendency to keep them in any other direction, or after a temporary effort has caused them to diverge from said parallelism. [...] The axle of the fore-carriage is situated a suitable distance behind the projection of the axis of the pivot-pin in order to ensure the stability of direction above referred to."

== See also ==
*[http://www.ozebiz.com.au/racetech/theory/align.html Camber, Caster, Toe - What does it all mean?]
* [[Camber angle]]
* [[Toe (automotive)]]
* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]

[[Category:Automotive technologies]]

[[ja:キャスター]]

File:Caster angle.png

2006-06-28T21:40:30Z

Philip rosenblum:

Caster angle

2006-06-28T21:39:53Z

Philip rosenblum:

[[image:caster_angle|thumb|300px|right|θ is the caster angle, red line is the pivot line, grey area is the tire]]
'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)|suspension]] of a steered [[wheel]] in a [[Automobile|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.

The pivot points of the [[steering]] are angled such that a line drawn through them intersects the road surface slightly ahead of the contact point of the wheel. The purpose of this is to provide a degree of self-centering for the steering - the wheel casters around so as to trail behind the axis of steering. This makes a car easier to drive and improves its straight line [[stability]] (reducing its tendency to wander). Excessive caster angle will make the steering heavier and less responsive, although, in racing, large caster angles are used to improve camber gain in cornering. Caster angles over 10 degrees with radial tires are common. Power steering is usually necessary to overcome the jacking effect from the high caster angle.

The steering axis (the dotted line in the diagram above) does not have to pass through the center of the wheel, so the caster can be set independently of the mechanical trail, which is the distance between where the steering axis hits the ground, in side view, and the point directly below the axle. The interaction between caster angle and trail is complex, but roughly speaking they both aid steering, caster tends to add damping, while trail adds 'feel', and returnability. In the extreme case of the shopping trolley (shopping cart in the US) wheel, the system is undamped but stable, as the wheel oscillates around the 'correct' path. The shopping trolley/cart setup has a great deal of trail, but no caster. Complicating this still further is that the lateral forces at the tire do not act at the center of the contact patch, but at a distance behind the nominal contact patch. This distance is called the pneumatic trail and varies with speed, load, steer angle, surface, tire type, tire pressure and time. A good starting point for this is 30 mm behind the nominal contact patch.

== History ==
[[Arthur Krebs]] applied the first the positive caster angle to automotive front-train in his [http://en.wikipedia.org/wiki/Image:Krebs_Boulogne_M_et_Mme_K_Auto_ACK_7_1896.jpg 1896 car] English patent : "To ensure stability of direction by means of a special arrangement of fore-carriage, that is to say, to re-establish automatically the parallelism of the two axles of the vehicle when there is no tendency to keep them in any other direction, or after a temporary effort has caused them to diverge from said parallelism. [...] The axle of the fore-carriage is situated a suitable distance behind the projection of the axis of the pivot-pin in order to ensure the stability of direction above referred to."

== See also ==
*[http://www.ozebiz.com.au/racetech/theory/align.html Camber, Caster, Toe - What does it all mean?]
* [[Camber angle]]
* [[Toe (automotive)]]
* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]

[[Category:Automotive technologies]]

[[ja:キャスター]]

File:Caster angle.svg.png

2006-06-28T21:34:48Z

Philip rosenblum:

Caster angle

2006-06-28T21:34:16Z

Philip rosenblum:

[[image:caster_angle.svg|thumb|300px|right|θ is the caster angle, red line is the pivot line, grey area is the tire]]
'''Caster''' (or '''castor''') '''angle''' is the angular displacement from the vertical axis of the [[suspension (vehicle)|suspension]] of a steered [[wheel]] in a [[Automobile|car]] or other [[vehicle]], measured in the longitudinal direction. It is the angle between the [[pivot line]] (an imaginary line that runs through the center of the upper [[ball joint]] to the center of the lower ball joint) and [[vertical]]. Car racers sometimes adjust caster angle to optimize car performance in particular driving situations.

The pivot points of the [[steering]] are angled such that a line drawn through them intersects the road surface slightly ahead of the contact point of the wheel. The purpose of this is to provide a degree of self-centering for the steering - the wheel casters around so as to trail behind the axis of steering. This makes a car easier to drive and improves its straight line [[stability]] (reducing its tendency to wander). Excessive caster angle will make the steering heavier and less responsive, although, in racing, large caster angles are used to improve camber gain in cornering. Caster angles over 10 degrees with radial tires are common. Power steering is usually necessary to overcome the jacking effect from the high caster angle.

The steering axis (the dotted line in the diagram above) does not have to pass through the center of the wheel, so the caster can be set independently of the mechanical trail, which is the distance between where the steering axis hits the ground, in side view, and the point directly below the axle. The interaction between caster angle and trail is complex, but roughly speaking they both aid steering, caster tends to add damping, while trail adds 'feel', and returnability. In the extreme case of the shopping trolley (shopping cart in the US) wheel, the system is undamped but stable, as the wheel oscillates around the 'correct' path. The shopping trolley/cart setup has a great deal of trail, but no caster. Complicating this still further is that the lateral forces at the tire do not act at the center of the contact patch, but at a distance behind the nominal contact patch. This distance is called the pneumatic trail and varies with speed, load, steer angle, surface, tire type, tire pressure and time. A good starting point for this is 30 mm behind the nominal contact patch.

== History ==
[[Arthur Krebs]] applied the first the positive caster angle to automotive front-train in his [http://en.wikipedia.org/wiki/Image:Krebs_Boulogne_M_et_Mme_K_Auto_ACK_7_1896.jpg 1896 car] English patent : "To ensure stability of direction by means of a special arrangement of fore-carriage, that is to say, to re-establish automatically the parallelism of the two axles of the vehicle when there is no tendency to keep them in any other direction, or after a temporary effort has caused them to diverge from said parallelism. [...] The axle of the fore-carriage is situated a suitable distance behind the projection of the axis of the pivot-pin in order to ensure the stability of direction above referred to."

== See also ==
*[http://www.ozebiz.com.au/racetech/theory/align.html Camber, Caster, Toe - What does it all mean?]
* [[Camber angle]]
* [[Toe (automotive)]]
* The 1896 [[Arthur Krebs]] automobile English patent: [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-01.jpg page 1] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-02.jpg 2] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-03.jpg 3] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-04.jpg 4] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-05.jpg 5] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-06.jpg 6] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-07.jpg 7] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-08.jpg 8] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-09.jpg 9] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-10.jpg 10] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-11.jpg 11] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-12.jpg 12] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-13.jpg 13] [http://rbmn08.waika9.com/Krebs_brevet_GB_07-09-1896-14.jpg 14]

[[Category:Automotive technologies]]

[[ja:キャスター]]

File:Car diagram.jpg

2006-06-28T21:32:34Z

Philip rosenblum:

Car handling

2006-06-28T21:32:06Z

Philip rosenblum:

'''Car handling''' and '''vehicle handling''' is a description of the way wheeled vehicles perform transverse to their direction of motion, particularly during cornering and swerving. It also includes their stability when moving in a straight line. Handling and braking are the major components of a vehicle's "active" safety. The maximum lateral acceleration is sometimes discussed separately as "road holding". Handling is an esoteric performance area because rapid and violent manoeuvres are often only used in unforeseen circumstances. (This discussion is directed at road vehicles with at least three wheels, but some of it may apply to other ground vehicles.)

Cars, for use on public roads, whose engineering requirements emphasise handling above passenger space and comfort, are called [[sports car]]s.

== Factors that affect a car's handling ==

=== Driver ===
Handling is a property of the car, but different characteristics will work well with different drivers.

=== Familiarity ===
A person learns to control a car much as he learns to control his body, so the more he has driven a car or type of car the better it will handle for him. One needs to take extra care for the first few thousand miles after buying a car, especially if it differs in design from those he is used to. Other things that a driver must adjust to include changes in tyres, tyre pressures and load. That is, handling is not just good or bad; it is also the same or different.

=== Weather ===
Weather affects handling by making the road slippery. Different [[tire|tyres]] do best in different weather. Deep water is an exception to the rule that wider tyres improve road holding. (See aquaplaning under tyres, below.)

=== Road condition ===
Cars with relatively soft suspension and with low unsprung weight are least affected by uneven surfaces, while on flat smooth surfaces the stiffer the better. Unexpected water, ice, oil, etc. are hazards.

=== Weight distribution ===
==== Center of gravity height ====

The center (centre) of gravity height, relative to the track, determines [[load transfer]], also called [[weight transfer]], from side to side and causes body lean. Centrifugal force acts at the center of gravity to lean the car toward the outside of the curve, increasing downward force on the outside tyres.

The centre of gravity height, relative to the wheelbase, determines load transfer between front and rear. The car's momentum acts at its center of gravity to twist the car forward or backward, respectively during braking and acceleration. Since it is only the downward force that changes and not the location of the center of gravity, the effect on over/under steer is ''opposite'' to that of an actual change in the center of gravity. When a car is braking, the downward load on the front tyres increases and that on the rear decreases, with corresponding change in their ability to take sideways load, causing oversteer.

Lower center of gravity is the principle performance advantage of [[sports car]]s, compared to sedans and (especially) SUVs.

Body lean can also be controlled by the springs, anti-roll bars or the roll center heights.

==== Roll angular inertia ====
This increases the time it takes to settle down and follow the steering. It depends on the (square of) the height and width.

Greater width, then, though it counteracts center of gravity hight, hurts handling by increasing angular inertia.

====Center of gravity forward or back ====
In steady-state cornering, front heavy cars tend to understeer and rear heavy cars to oversteer, all other things being equal. This can be compensated, at least mostly, by using wheels and tyres with size (width times diameter) proportional to the weight carried by each end.

When all four wheels and tyres are of equal size, as is most often the case with passenger cars, a weight distribution close to "50/50" (i.e. the [[Center of mass|centre of mass]] is mid-way between the front and rear axles) produces the preferred handling compromise. However, if unequal size tyres are acceptable, better handling is achieved by a rearward weight bias, using larger rear tyres to keep the steady-state cornering balance near neutral.

The rearward weight bias preferred by sports and racing cars results from handling effects during the transition from straight-ahead to cornering. During corner entry the front tyres, in addition to generating part of the lateral force required to accelerate the car's [[centre of mass]] into the turn, also generate a torque about the car's vertical axis that starts the car rotating into the turn. However, the lateral force being generated by the rear tyres is acting in the opposite torsional sense, trying to rotate the car out of the turn. For this reason, a car with "50/50" weight distribution will understeer on initial corner entry. To avoid this problem, sports and racing cars often have a more rearward weight distribution. In the case of pure racing cars, this is typically between "45/55" and "40/60." This gives the front tyres an advantage in overcoming the car's [[moment of inertia]] (yaw angular inertia), thus reducing corner-entry understeer.

Once a car is designed, weight distribution can be changed by using different diameter tyres or jacking the car up higher or lower at the suspension springs. Jacking is frequently done with screws or shims at the springs.

==== Yaw and pitch [[Moment of inertia|angular inertia]] (polar moment) ====
Unless the vehicle is very short, compared to its height or width, these are about equal. Angular inertia determines the [[rotational inertia]] of an object for a given rate of rotation.

The [[yaw]] angular inertia tends to keep the direction the car is pointing changing at a constant rate. This makes it slower to swerve or go into a tight curve, and it also makes it slower to turn straight again.
The pitch angular inertia detracts from the ability of the suspension to keep front and back tyre loadings constant on uneven surfaces and therefore contributes to bump steer.

Angular inertia is an integral over the ''square'' of the distance from the centre of gravity, so it favors small cars even though the lever arms (wheelbase and track) also increase with scale. (Since cars have reasonable symmetrical shapes, the off-diagonal terms of the angular inertia [[tensor]] can usually be ignored.)

=== Suspension ===
Automobile [[suspension (vehicle)|suspension]]s have many variable characteristics, which are generally different in the front and rear and all of which affect handling. Some of these are: [[spring rate]], damping, straight ahead [[camber angle]], camber change with wheel travel, roll centre height and the flexibility and vibration modes of the suspension elements. Suspension also affects unsprung weight.

Many cars have suspension that connects the wheels on the two sides, either by a [[sway bar]] and/or by a solid axle. The [[Citroën 2CV]] has interaction between the front and rear suspension.

The flexing of the frame interacts with the suspension. (See below.)

=== Tyres and wheels ===
In general, larger [[tire|tyres]], softer [[rubber]], higher [[hysteresis]] rubber and stiffer cord configurations increase road holding and improve handling. On most types of poor surfaces, large diameter [[wheel]]s perform better than lower wider wheels. The fact that larger tyres, relative to weight, stick better is the main reason that front heavy cars tend to understeer and rear heavy to oversteer. The depth of tread remaining greatly affects aquaplaning (riding over deep water without reaching the road surface). Increasing tyre pressures reduces their slip angle, but (for given road conditions and loading) there is an optimum pressure for road holding.

=== Track and wheelbase ===
The track provides the resistance to sideways weight transfer and body lean.
The wheelbase provides resistance to front/back weight transfer and provides the torque lever arm to rotate the car when swerving. The wheelbase, however, is less important than angular inertia (polar moment) to the vehicle's ability to swerve quickly.

=== Unsprung weight ===
[[Image:Car diagram.jpg|right]]
Ignoring the flexing of other components, a car can be modelled as the sprung weight, carried by the springs, carried by the [[unsprung weight]], carried by the tyres, carried by the road. Without the unsprung weight, the force of a tyre on the road would come from the vehicle weight and motion, transmitted by the spring. But the unsprung weight is cushioned from uneven road surfaces only by the springiness of the tyres (and wire wheels if fitted). To aggravate this (for [[fuel economy]] and to avoid overheating at high speed) tyres have limited internal damping. So the "wheel bounce" or resonant motion of the unsprung weight moving up and down on the springiness of the tyre is only poorly damped, mainly by the dampers or [[Shock absorber]]s of the suspension. For these reasons, high unsprung weight reduces road holding and increases unpredictable changes in direction on rough surfaces (as well as degrading ride comfort and increasing mechanical loads).

This unsprung weight includes the wheels and tyres, usually the [[brake]]s, plus some percentage of the suspension, depending on how much of the suspension moves with the body and how much with the wheels; for instance a solid axle is completely unsprung. The main factors that improve unsprung weight are a sprung differential (as opposed to [[live axle]]) and [[inboard brake]]s. (The [[De Dion tube]] suspension operates much as a live axle does, but represents an improvement because it is lighter, thereby reducing the unsprung weight.) [[Aluminium]] wheels also help. [[Magnesium]] wheels are even lighter but corrode easily.

Since only the brakes on the driving wheels can easily be inboard, the [[Citroën 2CV]] had additional dampers on its rear wheel hubs to damp only wheel bounce.

=== Aerodynamics===
[[Aerodynamic]] forces are generally proportional to the square of the air speed, therefore car aerodynamics become rapidly more important as speed increases. Like darts, aeroplanes, etc., cars can be stabilised by fins and other rear aerodynamic devices. However, in addition to this cars also use downforce or "negative lift" to improve road holding. This is prominent on many types of racing cars, but is also used on most passenger cars to some degree, if only to counteract the tendency for the car to otherwise produce positive lift.

In addition to providing increased adhesion, car aerodynamics are frequently designed to compensate for the inherent increase in [[oversteer]] as cornering speed increases. When a car corners, it must rotate about its vertical axis as well as translate its [[centre of mass]] in an arch. However, in a tight-radius (lower speed) corner the [[angular velocity]] of the car is high, while in a longer-radius (higher speed) corner the [[angular velocity]] is much lower. Therefore, the front tyres have a more difficult time overcoming the car's [[moment of inertia]] during corner entry at low speed, and much less difficulty as the cornering speed increases. So the natural tendency of any car is to understeer on entry to low-speed corners and oversteer on entry to high-speed corners. To compensate for this unavoidable effect, car designers often bias the car's handling toward less corner-entry understeer (such as by lowering the front [[roll center]]), and add rearward bias to the aerodynamic downforce to compensate in higher-speed corners. The rearward aerodynamic bias may be achieved by an airfoil or "spoiler" mounted near the rear of the car, but a useful effect can also be achieved by careful shaping of the body as a whole, particularly the aft areas.

=== Delivery of power to the wheels and brakes ===
The coefficient of friction of rubber on the road limits the magnitude of the vector sum of the transverse and longitudinal force. So the driven wheels or those supplying the most [[brake|braking]] tend to slip sideways. This phenomenon is often explained by use of the [[circle of forces]] model.

One reason that sports cars are usually rear wheel drive is that power induced oversteer is useful, to a skilled driver, for tight curves. The weight transfer under acceleration has the opposite effect and either may dominate, depending on the conditions. Inducing understeer by applying power in a front wheel drive car is less useful. In any case, this is not an important safety issue, because power is not normally used in emergency situations. Using low gears down steep hills may cause some oversteer.

The effect of braking on handling is complicated by [[load transfer]], which is proportional to the (negative) acceleration times the ratio of the centre of gravity height to the wheelbase. The difficulty is that the acceleration at the limit of adhesion depends on the road surface, so with the same ratio of front to back braking force, a car will understeer under braking on slick surfaces and oversteer under hard braking on solid surfaces. Most modern cars combat this by varying the distribution of braking in some way. This is important with a high centre of gravity, but it is also done on low centre of gravity cars, from which a higher level of performance is expected.

=== Position and support for the driver ===
Having to take up "g forces" in his/her arms interferes with a driver's precise steering. In a similar manner, a lack of support for the seating position of the driver may cause them to move around as the car undergoes rapid acceleration (through cornering, taking off or braking). This interferes with precise control inputs, making the car more difficult to control.

Being able to reach the controls easily is also an important consideration, especially if a car is being driven hard.

Driver position and support is also an important safety consideration, as during an accident considerable forces are applied to the driver, who must be restrained as much as possible from hitting hard objects (such as the steering wheel, windscreen, side windows or B-pillar). A supportive seat and good seat belt contibute to holding the driver in place, although these may be augmented with further active safety devices.

=== Steering ===
Depending on the driver, [[steering]] force and transmission of road forces back to the steering wheel and the steering ratio of turns of the steering wheel to tuns of the road wheels affect control and awareness. Play — free rotation of the steering wheel before the wheels rotate — is a common problem, especially in older model and worn cars. Another is friction. [[Rack and pinion]] steering is generally considered the best type of mechanism for control effectiveness. The linkage also contributes play and friction. Caster — offset of the steering axis from the contact patch — provides some of the self centring tendency.

Precision of the steering is particularly important on ice or hard packed snow where the slip angle at the limit of adhesion is smaller than on dry roads.

The steering effort depends on the downward force on the steering tyres and on the radius of the contact patch. So for constant tyre pressure, it goes like the 1.5 power of the vehicle's weight. The driver's ability to exert torque on the wheel scales similarly with her size. The wheels must be rotated farther on a longer car to turn with a given radius. [[Power steering]] reduces the required force at the expense of feel. It is useful, mostly in parking, when the weight of a front-heavy vehicle exceeds about ten or fifteen times the driver's weight, for physically impaired drivers and when there is much friction in the steering mechanism.

[[Steering#Four-wheel steering|Four-wheel steering]] has begun to be used on road cars (Some WW II reconnaissance vehicles had it). It relieves the effect of angular inertia by starting the whole car moving before it rotates toward the desired direction. It can also be used, in the other direction, to reduce the turning radius. Some cars will do one or the other, depending on the speed.

Steering geometry changes due to bumps in the road may cause the front wheels to steer in a different directions together or independent of each other. The steering linkage should be designed to minimise this effect.

=== Suspension travel ===
The severe handling vice of the [[Triumph TR3B|TR3]] and related cars was caused by running out of suspension travel. (See below.)
Other vehicles will run out of suspension travel with some combination of bumps and turns, with similarly catastrophic effect. Excessively modified cars also may encounter this problem.

=== [[Electronic stability control]] ===
Since automobile safety is mainly a control issue, one should expect a largely electronic solution. Apparently there has already been some advance in this direction.

On the other hand, since stability control works by reducing sudden manoeuvres, until the electronics helps to detect the danger sooner, it can never take the place of a low centre of gravity, which provides both stability and fast avoidance. (See [[Wireless vehicle safety communications]].)

The stability control of some cars may not be compatible with some driving techniques, such as power induced over-steer. It is therefore, at least from a sporting point of view, preferable that it can be disabled.

=== Alignment of the wheels ===
Of course things should be the same, left and right.
Toe in affects steering because a tyre tends to move in the direction the top of it is leaning.

=== Rigidity of the frame ===
The frame may flex with load, especially twisting on bumps.
Rigidity is considered to help handling. At least it simplifies the suspension engineers work.
Some cars, such as the [[Mercedes-Benz 300SL]] have had high doors to allow a stiffer frame.

== Common handling problems ==
When any wheel leaves contact with the road there is a change in handling, so the suspension should keep all four (or three) wheels on the road in spite of hard cornering, swerving and bumps in the road. It is very important for handling, as well as other reasons, not to run out of suspension travel and "bottom" or "top".

It is usually most desirable to have the car adjusted for neutral steer, so that it responds predictably to a turn of the steering wheel and the rear wheels have the same slip angle as the front wheels. However this may not be achievable for all loading, road and weather conditions, speed ranges, or while turning under acceleration or braking. Ideally, a car should carry passengers and baggage near its centre of gravity and have similar tyre loading, [[camber angle]] and roll stiffness in front and back to minimise the variation in handling characteristics. A driver can learn to deal with oversteer or understeer, but not if it varies greatly.

The most important common handling failings are;

*[[Understeer]] - the front wheels tend to crawl slightly or even slip and drift towards the outside of the turn. The driver can compensate by turning a little more tightly, but road-holding is reduced, the car's behaviour is less predictable and the tyres are liable to wear more quickly.

*[[Oversteer]] - the rear wheels tend to crawl or slip towards the outside of the turn more than the front. The driver must correct by steering away from the corner, otherwise the car is liable to spin, if pushed to its limit. Oversteer is sometimes useful, to assist in steering, especially if it occurs only when the driver chooses it by applying power.

*[[Bump steer]] – is the tendency for unevenness of a road surface to affect the yaw angle (heading) of the car. This will always happen under some conditions but depends on suspension, steering linkage, unsprung weight, angular inertia, differential type, frame rigidity, tyres and tyre pressures. Extreme bump steer may results when a vehicle's suspension travel is exhausted so that a wheel either bottoms or leaves the road. As with hard turning on flat roads, it is better if the wheel picks up by the spring reaching its neutral shape, rather than by suddenly contacting a limiting structure of the suspension.

*[[Body roll]] - the car leans towards the outside of the curve. This interferes with the driver's control, because he must wait for the car to finish leaning before he can fully judge the effect of his steering change. It also adds to the delay before the car moves in the desired direction.

*[[Weight transfer]] - the wheels on the outside of a curve are more heavily loaded than those on the inside. This tends to overload the tyres on the outside and therefore reduce road holding. Weight transfer (sum of front and back), in steady cornering, is determined by the ratio of the height of a car's centre of gravity to its track. Differences between the weight transfer in front and back are determined by the relative roll stiffness and contribute to the over or under-steer characteristics.
**When the weight transfer equals half the vehicle's loaded weight, it will start to [[Rollover|roll over]]. This can be avoided by manually or automatically reducing the turn rate, but this causes further reduction in road-holding. (A collision may be preferable to a rollover.)

*'''Slow response''' - sideways acceleration does not start immediately when the steering is turned and may not stop immediately when it is returned to centre. This is partly caused by body roll. Other causes include tyres with high slip angle, and yaw and roll angular inertia. Roll angular inertia aggravates body roll by delaying it. Soft tyres aggravate yaw angular inertia by waiting for the car to reach their slip angle before turning the car.

== Compromises ==
For ordinary production cars, manufactures err towards deliberate understeer as this is safer for inexperienced or inattentive drivers than is oversteer. Other compromises involve comfort and utility, such as preference for a softer smoother ride or more seating capacity. High levels of comfort are incompatible with a low centre of gravity, body roll resistance, low angular inertia, support for the driver, steering feel and other characteristics that make a car handle well.
Inboard brakes improve both handling and comfort but take up space and are harder to cool. Large engines, tend to make cars front or rear heavy. In tyres, fuel economy, staying cool at high speeds, ride comfort and long wear all tend to conflict with road holding, while wet, dry, deep water and snow road holding are not exactly compatible. A-arm or [[wishbone]] front suspension tends to give better handling, because it provides the engineers more freedom to choose the geometry, and more road holding, because the camber is better suited to radial tyres, than [[MacPherson strut]], but it takes more space.
Live solid axle rear suspension is mainly used to reduce cost, but, in general, cost is a relatively less important factor.

In fact, cost may sometimes be ''negatively'' correlated with handling, because small size, though it makes little difference in the cost of the car itself, improves both handling and fuel economy (as well as braking, parking, etc.). This may have been true in the US in the late 1950s when many of the European imports undersold the Detroit "dinosaurs". It may again be true in the 2000s, now that large cars, called SUVs or styled as pickups, have regained popularity.

== [[Aftermarket (automotive)|Aftermarket]] modifications and adjustments to affect handling ==
{| border="1" style="width:600px; border-collapse:collapse" cellspacing="0" cellpadding="5"
!bgcolor="#ccccee"| Component
!bgcolor="#ccccee"| Reduce Under-steer
!bgcolor="#ccccee"| Reduce Over-steer
|-
| Weight distribution || [[center of gravity|centre of gravity]] towards rear || centre of gravity towards front
|-
| Front [[shock absorber]] || softer || stiffer
|-
| Rear shock absorber || stiffer || softer
|-
| Front [[sway bar]] || softer || stiffer
|-
| Rear sway bar || stiffer || softer
|-
| Front [[tire|tyre]] selection1 || larger [[Contact patch|contact area]]2 || smaller contact area
|-
| Rear tyre selection || smaller contact area || larger contact area2
|-
| Front wheel rim width or diameter || larger2 || smaller
|-
| Rear wheel rim width or diameter || smaller || larger2
|-
| Front tyre pressure || higher pressure || lower pressure
|-
| Rear tyre pressure || lower pressure || higher pressure
|-
| Front wheel [[Camber angle|camber]] || increase negative camber || reduce negative camber
|-
| Rear wheel camber || reduce negative camber || increase negative camber
|-
| Rear [[Spoiler (automotive)|spoiler]] || smaller || larger
|-
| Front height (because these usually   affect camber and roll resistance) || lower front end || raise front end
|-
| Rear height || raise rear end || lower rear end
|-
| Front [[toe (automotive)|toe]] in || increase || decrease
|-
| Rear toe in || decrease || increase
|-
|colspan=3 bgcolor="#eeeeee"| 1) tyre contact area can be increased by using wider tyres, or tyres with fewer grooves in the tread pattern. Of course fewer grooves has the opposite effect in wet weather or other poor road conditions.

2) These also improve road holding, under most conditions.
|}

In addition, lowering the centre of gravity will always help the handling (as well as reduce the chance of roll-over). This can be done to some extent by using plastic windows (or none) and light roof, hood (bonnet) and boot (trunk) lid materials, by reducing the ground clearance, etc. Increasing the track with "reversed" wheels will have a similar effect, but remember that the wider the car the less spare room it has on the road and the farther you may have to swerve to miss an obstacle.
Stiffer springs and/or shocks, both front and rear, will generally improve handling, at the expense of comfort on small bumps. Performance suspension kits are available.
Light alloy (mostly aluminium or magnesium) wheels improve handling and ride as well as appearance.

Moment of inertia can be reduced by using lighter bumpers and wings (fenders), or none at all.

== Cars with unusual handling problems ==
* [[Porsche 911]] — the inside front wheel leaves the road during hard cornering on dry pavement. This causes increasing understeer, but it is still considered to have acceptable handling, even for a sports car. The roll bar stiffness at the front is set to compensate for the rear-heaviness and gives neutral handling in ordinary driving. This compensation starts to give out when the wheel lifts. Later model 911s have had increasingly sophisticated rear suspensions and larger rear tyres.
* Triumph TR2, [[Triumph TR3B|TR3]] and [[Triumph TR4|TR4]] — began to oversteer more suddenly when their inside rear wheel lifted.
* [[Mercedes-Benz A-Class]] — early models showed excessive body roll during sharp swerving manoeuvres, most particularly during the Swedish [[moose test]]. This was later corrected using [[Electronic Stability Control]] and retrofitted at great expense to earlier cars.
* [[Volkswagen Beetle]] — (original Beetle, for young people) The limitations of the Beetle's handling and roll stability were blamed, by [[Ralph Nader]], on the swing axle suspension, but that appears to have been based more on political aspirations than on engineering knowledge. Since its design was based closely on Porsche's Auto Union grand prix car in the 1930s, it is surprising for many to hear that it was neither top heavy (as its appearance would suggest) nor particularly rear-heavy (in fact a well ballanced 42/58). Since they were produced for so long, with stickier tyres and more powerful engines, people who drove them hard fitted reversed wheels and bigger rear tyres and rims.
* The gaudy 1950s American "full size" "dinosaurs" — responded very slowly to steering changes, because of their very large angular inertia, soft but simple suspension and comfort oriented cross bias tyres. ''Auto Motor und Sport'' reported on one of these that they lacked the courage to test it for top speed. Contact with Europe and the 1970s energy crisis have gradually relieved this problem. (Large trucks, also, cannot be made to respond quickly because of their angular inertia.)
* [[Dodge Omni]] and [[Plymouth Horizon]] — these early American responses to the [[Volkswagen Rabbit]] were found "Unacceptable" in their initi

File:Camber angle.jpg

2006-06-28T21:30:15Z

Philip rosenblum:

Boost ventilator

2006-06-28T21:26:44Z

Philip rosenblum:

{{linkless}}
A '''boost ventilator''' is an enclosed system of [[duct]]s and [[Fan (implement)|mechanical fan]]s that circulates fresh, recycled or conditioned air at varying degrees of temperature and variable speeds within an [[automobile]].

[[Category:Automotive technologies]]

{{auto-part-stub}}

Bodywork

2006-06-28T21:23:38Z

Philip rosenblum:

There are two main types of bodywork:

1) Human Touch Bodywork:

This "bodywork" refers to the touch and/or manipulation of one body by another for healing/health reasons. Most popular in this category are [[massage]], [[chiropractic]], [[osteopathy]], [[Breema]], [[Shiatsu]], and [[Soft Tissue Therapy]].

2) In [[automotive engineering]], the '''bodywork''' of an [[automobile]] is the structure which protects:

* The occupants
* Any other payload
* The mechanical components.

In vehicles with a frame or [[chasis]], the term ''bodywork'' is normally applied to only the non-structural panels, including doors and other movable panels, but it may also be used more generally to include the structural components which support the mechanical components.

==Construction==

Automotive Bodywork

There are three main types of automotive bodywork:

* The first automobiles were modelled on horse-drawn vehicles, and had [[body-on-frame]] construction with a wooden frame and wooden or metal body panels. Wooden-framed motor vehicles remained in production until the middle of the 20th century, for example the [[MG A]] which continued in production until 1962.

* A steel [[chasis]] or ladder frame replaced the wooden frame. This form of body-on-frame construction is still common for [[truck]]s.

* [[Monocoque]] construction, in which the metal body itself provides support as well as protection and there is no separate frame or chasis. Steel monocoque construction is now the most common form of car bodywork.

Less common types include [[tube frame]] and [[space frame]] designs used for high-performance cars. There have also been various [[Hybrid Cars|hybrids]], for example the [[Volkswagen Beetle]] had a chasis, consisting of the floor pan, door sills and central tunnel, but this chasis relied on the stiffening provided by the bodywork, a technique sometimes called ''semi-monocoque'' construction.

Non-structural body panels have been made of [[wood]], [[steel]], [[aluminium]], [[fibreglass]] and several more exotic materials.

==Body styles==

There are several common car body styles:

* Enclosed:
** [[Sedan]], known as a Saloon in British English.
** [[Hard top]]
** [[Coupe]]
** [[Limousine]]
* Open or partly enclosed:
** [[Roadster]]
** [[Convertible]]
** [[Cabrio]]
* Rear door designs:
** [[Station wagon]] or Estate car
** [[Hatchback]]
** [[Liftback]]
* Other:
** Ute, also known as a [[Coupe Utility]] or [[sport utility vehicle]]

==See also==
* [[Body-on-frame]], a general term covering both wooden-frame and steel-chasis vehicles.
* [[Car body styles]] for a more complete list of body styles.
* [[:Category:Car body styles]] for a list of Wikipedia articles on particular body styles.

[[Category:automotive technologies]]

Body-on-frame

2006-06-28T21:22:00Z

Philip rosenblum:

'''Body-on-frame''' is an [[automobile]] construction technology. Mounting a separate body to a rigid frame which supports the [[drivetrain]] was the original method of building automobiles, and its use continues to this day. The original frames were made of wood (commonly [[ash tree|ash]]), but steel '''ladder frames''' became common in the [[1930s]].

In the USA the frequent changes in [[automobile design]] made it necessary to use a ladder frame rather than [[monocoque]] to make it possible to change the design without having to change the [[chassis]], allowing frequent changes and improvements to the car's bodywork and interior (where they were most noticable to customers) while leaving the chassis and driveline unchanged, and thus keeping cost down and design time short. It was also easy to use the same chassis and driveline for several very different cars. Especially in the days before [[computer-aided design]], this was a big advantage. [http://www.findarticles.com/p/articles/mi_m0KJI/is_2_115/ai_97872909]

Most small passenger vehicles switched to [[unibody]] construction in the [[1960s]], leaving just [[truck]]s, [[bus]]es and large cars using conventional frames. The switch continued for several decades - even [[SUV]]s typically use unibody construction today. Body-on-frame remains the preferred construction method for heavy-duty vehicles, especially those which are intended to carry and pull heavy loads.

The [[Lincoln (automobile)|Lincoln]] [[Town Car]] dominates the American limousine market because it is the last American luxury car made with body-on-frame, which makes it easy to "stretch."

==Advantages and disadvantages compared to unibody==
=== Advantages ===
* Generally more comfortable because fewer vibrations from engine and wheels reach the driver
* Easier to design, build and modify (less of an issue now [[CAD]] is commonplace)
* More suited for heavy duty usage and more durable
* Easier to modify

=== Disadvantages ===
* Heavier than unibody
* Center of gravity is usually higher
* Less resistant to torsion (flexing of the whole car in corners)

==See also==
* [[Coachwork|Carrossery]]
* [[Monocoque]]
* [[Spaceframe]]
* [[Subframe]]
* [[Superleggera]]

==External Links & Sources==

1. [http://www.findarticles.com/p/articles/mi_m0KJI/is_2_115/ai_97872909 Article about body-on-frame in modern cars and trucks]

2. [http://www.findarticles.com/p/articles/mi_m3012/is_n1_v178/ai_20160852 Body on frame and unibody in SUVs]

3. [http://www.oldchesterpa.com/ford_assembly_pics.htm Ford assembly line featuring body-on-frame car (historic)]

[[Category:Automotive technologies]]

Body-on-frame

2006-06-28T21:20:45Z

Philip rosenblum:

Body-on-frame is an automobile construction technology. Mounting a separate body to a rigid frame which supports the drivetrain was the original method of building automobiles, and its use continues to this day. The original frames were made of wood (commonly ash), but steel ladder frames became common in the 1930s.

In the USA the frequent changes in automobile design made it necessary to use a ladder frame rather than monocoque to make it possible to change the design without having to change the chassis, allowing frequent changes and improvements to the car's bodywork and interior (where they were most noticable to customers) while leaving the chassis and driveline unchanged, and thus keeping cost down and design time short. It was also easy to use the same chassis and driveline for several very different cars. Especially in the days before computer-aided design, this was a big advantage. [1]

Most small passenger vehicles switched to unibody construction in the 1960s, leaving just trucks, buses and large cars using conventional frames. The switch continued for several decades - even SUVs typically use unibody construction today. Body-on-frame remains the preferred construction method for heavy-duty vehicles, especially those which are intended to carry and pull heavy loads.

The Lincoln Town Car dominates the American limousine market because it is the last American luxury car made with body-on-frame, which makes it easy to "stretch."
Contents
[hide]

* 1 Advantages and disadvantages compared to unibody
o 1.1 Advantages
o 1.2 Disadvantages
* 2 See also
* 3 External Links & Sources

[edit]

Advantages and disadvantages compared to unibody
[edit]

Advantages

* Generally more comfortable because fewer vibrations from engine and wheels reach the driver
* Easier to design, build and modify (less of an issue now CAD is commonplace)
* More suited for heavy duty usage and more durable
* Easier to modify

[edit]

Disadvantages

* Heavier than unibody
* Center of gravity is usually higher
* Less resistant to torsion (flexing of the whole car in corners)

[edit]

See also

* Carrossery
* Monocoque
* Spaceframe
* Subframe
* Superleggera

[edit]

External Links & Sources

1. Article about body-on-frame in modern cars and trucks

2. Body on frame and unibody in SUVs

3. Ford assembly line featuring body-on-frame car (historic)
Retrieved from "http://en.wikipedia.org/wiki/Body-on-frame"

Categories: Automotive technologies

File:Fcvgc-updated.gif

2006-06-27T23:38:54Z

Philip rosenblum:

File:Ev1crushed.jpg

2006-06-27T23:37:23Z

Philip rosenblum:

File:Eliica.jpg

2006-06-27T23:37:12Z

Philip rosenblum:

File:Detroit Eletric ad.jpg

2006-06-27T23:36:55Z

Philip rosenblum:

File:1991.jpg

2006-06-27T23:36:34Z

Philip rosenblum:

File:VenturiFetish.jpg

2006-06-27T23:36:15Z

Philip rosenblum:

Battery electric vehicle

2006-06-27T23:31:50Z

Philip rosenblum:

{{TOCright}}

'''Battery electric vehicles''' or '''BEV'''s are [[electric vehicle]]s whose main energy storage is in the chemical energy of [[Rechargeable battery|batteries]].
BEVs are the most common form of what is defined by the California Air Resources Board ([[CARB]]) as [[Zero emission vehicle|zero emission]] (ZEV) passenger [[automobile]]s, because they produce no emissions while being driven. The [[Electricity|electrical]] [[energy]] carried onboard a BEV to power the motors is obtained from a variety of [[Rechargeable battery|battery]] chemistries arranged into [[battery pack]]s. For additional range [[genset trailer]]s or [[pusher trailer]]s are sometimes used, forming a type of [[hybrid vehicle]]. Batteries used in electric vehicles include "flooded" [[Lead-acid battery|lead-acid]], [[absorbed glass mat]], [[Nickel-cadmium battery|NiCd]], [[nickel metal hydride]], [[Li-ion]], [[Lithium ion polymer battery|Li-poly]] and [[Zinc-air battery|zinc-air batteries]] and the [[Molten salt battery]].

While [[hybrid vehicle]]s apply many of the technical advances first developed for BEVs, they are not considered BEVs. Of interest to BEV developers, however, is the fact that [[Hybrid Cars|hybrid vehicles]] are advancing the state of the art (in cost/performance ratios) of batteries, electric motors, chargers, and motor controllers, which may bode well for the future of both pure electric vehicles and the so called "plug-in [[Hybrid Cars|hybrid]]".

[[Image:VenturiFetish.jpg|thumb|right|300px|[[Venturi Fetish]] - a limited production electric car capable of reaching 0-100km/h in 4.5 seconds]]
==History==
{{main|History of the electric vehicle}}
BEVs were among the earliest automobiles, and before the preeminence of powerful, but polluting [[internal combustion engines]], electric automobiles held many vehicle land speed and distance records in the early 1900s. Most notable was perhaps breaking of the 100 km/h (62.5 mph) speed barrier by [[Camille Jenatzy]] on [[April 29]], [[1899]] in his rocket-like EV named ''La Jamais Contente''. It reached a top speed of 105.88 km/h (65.79 mph)

BEVs were produced by [[Anthony Electric]], [[Baker Electric]], [[Detroit Electric]], and others during the first part of the 20th century and actually out-sold gasoline-powered vehicles at one point in time. Due to technological limitations and the lack of [[transistor]]-based electric technology, the top speed of these early production electric vehicles was limited to approximately 20 miles per hour. They were successfully sold as town cars to upper class customers and often marketed as suitable vehicles for women drivers due to their cleanliness, lack of noise and ease of operation.

Some feel that the introduction of the [[electric starter]] by [[Cadillac (automobile)|Cadillac]] in [[1913]], which simplified the difficult and sometimes dangerous task of starting the internal combustion engine, was the downfall of the electric vehicle, as [[1912]] may have been the pinnacle year for BEVs. Still others point out that it was [[radiator]]s, in use as early as [[1895]] by [[Panhard-Levassor]] in their [[Systeme Panhard]] design [http://inventors.about.com/library/weekly/aacarsassemblya.htm], which allowed engines to keep cool enough to run for more than a few minutes, before which they had to stop and cool down at horse troughs along with the [[steam car|steamers]] to replenish their water supply. The truth may be that EV's had fallen out of favor over the mass produced [[Ford Model-T]] which went into production four years earlier in [[1908]]. [http://www.econogics.com/ev/evhistry.htm] Ultimately, technological advances in internal-combustion powered cars advanced beyond that of their electric powered competitors, resulting in the superior performance and practicality of gasoline powered cars. By the late 1930s the early electric automobile industry had completely disappeared, with battery-electric traction being limited to niche application such as industrial vehicles.

The 1947 invention of the point-contact [[transistor]] marked the beginning of a new era for electric technology. Within a decade, Henney Coachworks had joined forces with National Union Electric Company (makers of Exide Batteries) to produce the first modern electric car based around transistor technology. The [[Henney Kilowatt]] was produced in 36 volt and 72 volt configurations. The 72 volt models had a top speed approaching 60 miles per hour (96 km/h) and could travel nearly 60 miles on a full charge. Despite the improved practicality of the Henney Kilowatt over previous electric cars, the cost of production exceeded the price that consumers were willing to pay for the Henney Kilowatt and production was ended by 1961.

==Efficiency==
[[Image:Fcvgc-updated.gif|400px|right|http://www.eren.doe.gov]]
Production and [[Electric vehicle conversion|conversion]] battery electric vehicles typically achieve 0.3 to 0.5 kWh per mile (0.2 to 0.3 kWh/km). [http://avt.inel.gov/fsev.html] [http://avt.inel.gov/pdf/fsev/eva/ev1_eva.pdf]  Nearly half of this power consumption is due to inefficiencies in charging the batteries. The U.S. fleet average of 23 mpg of [[gasoline]] is equivalent to 1.58 kWh/mi and the 70 mpg [[Honda Insight|Insight]] gets 0.52 kWh/mi (assuming 36.4 kWh per U.S. gallon of gasoline), so battery electric cars vehicles are relatively efficient. When comparisons are made for the total energy cycle, the efficiency figures for BEVs drop, but such calculations are ''not'' commonly offered for ICE vehicles (e.g. the loss of efficiency from energy used to produce specialized fuels such as gasoline as compared to the raw energy available from [[crude oil]] or [[natural gas]].

CO2 emission comparisons [http://www.fueleconomy.gov/feg/byfueltype.htm] are one good indication of the current grid-mix vs gasoline consumption. Such comparisons include production, transmission, charging, and vehicle losses. The CO2 emissions can improve for BEVs through the use of sustainable grid or local resources but are essentially fixed for gasoline vehicles. Unfortunately the [[EV1]], [[Ford Ranger EV|Ranger EV]], EVPlus, and other production vehicles are missing from this site.

*RAV4-EV vs Gas RAV4
**2000 Toyota RAV4-EV 4.1 [[short ton]]s CO2 (104 mpg)
**2000 Toyota RAV4 2wd 7.2 short tons CO2 (26 mpg)
*Other BEVs
**2000 Nissan Altra EV 3.5 short tons CO2
**2000 Nissan Altra EV 3.5 short tons CO2
**2002 Toyota RAV4-EV 3.8 short tons CO2
**2002 Ford Explorer 7.8 short tons CO2 (USPS)
*[[Hybrid Cars|Hybrids]]
**2000 Honda Insight 3.0 short tons CO2
**2001 Honda Insight 3.1 short tons CO2
**2005 Toyota Prius 3.5 short tons CO2
**2005 Ford Escape H 2x 5.8 short tons CO2
**2005 Ford Escape H 4x 6.2 short tons CO2
*Standard ICE vehicles
**2005 Dodge Neon 2.0L 6.0 short tons CO2
**2005 Ford Escape 4x 8.0 short tons CO2
**2005 GMC Envoy XUV 4x 11.7 short tons CO2

It is important to study the full effect of any vehicle design, especially when promoted as better than the status quo. The goal may be to look at overall efficiency only or it may be the total environmental impact, since environmental damage reduction is often the goal behind alternative vehicle efforts. Many factors must be considered when making an overall comparison of total environmental impact. The most comprehensive comparison is known as a cradle-to-grave or lifecycle analysis. The analysis considers all inputs including original production and fuel sources and all outputs and end products including emissions and disposal. The varying amounts and types of outputs and inputs vary in their environmental effects and are difficult to directly compare. For example, are the environmental effects of [[nickel]] or [[cadmium]] [[pollution|contamination]] from a battery production facility less than those of [[hydrocarbon]] [[emission]]s or from [[petroleum]] [[Oil refinery|refining]]? If so, how much, or how much of each would be equivalent? Similar types of questions would need to be resolved for each input and output in order to make a comparison.

A large lifecycle input difference is that the electric vehicle requires electricity instead of a liquid fuel. The advantage of the electric vehicle is that the electricity can be provided by [[renewable energy]]. However, if the electricity is produced from [[fossil fuel]] sources (as most electricity currently is) the advantage of the electric vehicle is reduced, or nearly eliminated. [http://www.ilea.org/lcas/taharaetal2001.html] Thus utilizing and developing additional renewable energy sources is required for electric vehicles to further reduce their net emissions.

The input for electric vehicle production that differs from internal combustion types is primarily in the large battery. Modern batteries as used in [[Hybrid Cars|hybrids]] and BEVs have been tested to out-live the vehicle they are tested in. Tested batteries as used by toyota have shown only minimal degradation in performance after 150,000 miles. BEVs do not require an ICE engine, support systems or related maintenance, so they should be more reliable and require less maintenance. Although BEVs are not common, there are related markets which require advances in battery technology, such as mobile phones, laptops, forklifts and [[Hybrid Cars|hybrid]] electric vehicles. Improvements to battery technology for any of these other markets will make BEVs more practical too.



Aerodynamic drag has a big impact on efficiency as the speed of the vehicle increases. A list of cars and their corresponding [[drag coefficient]]s is listed [[Drag coefficient#Typical values and examples|here]].

==Performance==
Many of today's electric vehicles are capable of acceleration performance which exceeds that of conventional gasoline powered vehicles. Electric vehicles can utilize a direct motor to wheel configuration which increases the power deliverability to the wheels. Having multiple motors connected directly to the wheels allows for each of the wheels to be used for both propulsion and as braking systems, thereby increasing traction. In some cases, the motor can be housed directly in the wheel, such as in the [[Whispering Wheel]] design, which lowers the center of gravity and reduces the number of moving parts. When not fitted with an axle, differential or transmission, many electric vehicles have greater torque availability, which goes directly to accelerating the wheels. A gearless or single gear design in some electric vehicles eliminates the need for gear shifting, giving the newer electric vehicles both smoother acceleration and braking. This also allows higher torque at wide rpm levels. For example, the [[Venturi Fetish]] delivers [[supercar]] acceleration despite having a relatively modest 300 [[HP|horsepower]]. Its top speed is only around 100 mph, however. Some electric vehicles, such as some DC motor-equipped drag racers, have simple two-speed transmissions to improve top speed [http://nedra.com/100mph_club.html][http://nedra.com/125mph_club.html]. Larger vehicles, such as electric trains and land speed record vehicles, overcome this speed barrier by dramatically increasing the wattage of their power system.

==Fuels==
There are no currently available technologies which can provide all of the energy required for the life of a BEV car. This means that all BEV cars must be refuelled by periodic charging of the batteries.

BEVs most commonly charge from the [[power grid]], which is in turn generated from a variety of domestic resources — primarily [[Hydroelectricity]], coal, natural gas, and nuclear. Home power such as roof top photovoltaic (solar cell) panels, microhydro or wind can also be used. Electricity can also be supplied with traditional fuels via a generator. Although not strictly a BEV, the [[Ford Reflex]] concept car incorporates solar cells into its exterior to help power its [[Hybrid Cars|hybrid]] powertrain.
 

==Range==
The range of a BEV depends greatly on the number and type of batteries used. The weight and type of vehicle also has an impact just as it does on the mileage of traditional vehicles. Conversions usually use lead-acid batteries because they are the most available and inexpensive, such conversions generally have 20 to 50 miles (30 to 80 km) of range and are built to satisfy the drivers' individual needs. Production EVs with lead-acid batteries are capable of up to 80 miles (130 km) per charge. NiMH chemistries have high energy density and can deliver up to 120 miles (200 km) of range. Lithium ion equipped EVs have been claimed in [[press release]]s to have 250-300 miles (400-500 km) of range per charge[http://www.acpropulsion.com/LiIon_tzero_release.pdf]. EVs can also use [[pusher trailer]]s or [[genset trailer]]s in order to function as a [[hybrid vehicle]] for occasions when unlimited range is desired without the additional weight during normal short range use. The vehicle becomes an internal combustion vehicle when utilizing the trailer, but it allows the greater range that may be needed for limited times while making the advantages of the BEV available for most shorter trips.

In practice most vehicle journeys of all kinds are quite short, the majority being under 30 km (20 mi) per day. Thus, a BEV that can do 60 km (40 mi) in a day is quite practical for most trips for most users, and a substantial additional range can be added for commuters where charging facilities are available at the destination.



==Battery charging vs. battery replacing ==
The charging time is limited primarily by the capacity of the [[grid]] connection. A normal [[household]] [[outlet]] is between 1.5 [[kW]] in the US to 3 kW in the rest of the world (countries with 240 [[V]] supply). The main connection to a house might be able to sustain 10 kW, and special wiring can be installed to use this. At this higher power level charging even a small, 7 kWh (14–28 mi) pack, would probably require one hour. Compare this to the effective power delivery rate of an average [[petro]] [[pump]], about 5,000 kW. Even if the supply power can be increased, most batteries do not accept charge at greater than their 'charge rate' C1.

Some recent [[handheld]] device battery designs by [[Toshiba]] [http://www.toshiba.co.jp/about/press/2005_03/pr2901.htm] are claimed to be capable of accepting an 80% charge in as little as 60 seconds. Scaling this [[specific power]] characteristic up to the same 7 kWh EV pack would result in the need for a peak of 336 kW  of power from some source for those 60 seconds. It is not clear that such batteries will work directly in BEVs as heat build-up may make them unsafe.

Most people do not require fast recharging because they have enough time (6 to 8 hours) during the work day or [[overnight]] to refuel. As the charging does not require attention it takes a few seconds for an owner to [[plug]] in and unplug their vehicle. Many BEV drivers prefer refueling at home, avoiding the inconvenience of visiting a [[fuel station|petro-station]]. Some workplaces provide special parking [[bay]]s for electric vehicles with charging equipment provided.

The charging power can be connected to the car in two ways:

*The first is a direct electrical connection known as [[conductive]] [[coupling]]. This might be as simple as a [[mains]] lead into a [[weather]] [[proof]] [[socket]] through to special high capacity cables with connectors to protect the user from [[high voltage]]s.

*The second approach is known as [[inductive]] coupling. A special '[[paddle]]' is inserted into a [[slot]] on the car. The paddle is one winding of a [[transformer]], while the other is built into the car. When the paddle is inserted it completes a magnetic circuit which provides power to the battery pack. The major advantage of this approach is that there is no possibility of [[electrocution]] as there are no exposed conductors although interlocks can make conductive coupling nearly as safe. Conductive coupling equipment is lower in cost and much more efficient due to a vastly lower component count.

An alternative to recharge is to '''[[wikt:replace|replace]]'''. Uncharged [[standardized]] electric car batteries (i.e. the [[de facto]] Zebra standard batteries) can be replaced by charged ones in the fuel stations, car shops or similar places. This replacement can be [[automatic]] or manual.

==Battery life==
Individual batteries are usually arranged into large [[battery pack]]s of various [[voltage]] and [[ampere-hour]] capacity products to give the required energy capacities. Battery life must be considered when calculating cost of operation, as all batteries wear out and must be replaced. The rate at which they expire depends on a number of factors.

New scientific and empirical evidence from running individual EV conversions shows that most of these negative factors linked to batteries connected in series for traction application can be mitigated with good DC/DC based [[Battery Management System]], thermo insulation/venting, and proper care. That also includes selecting a well balanced mix of components oriented towards specific performance properties, i.e. range, speed. For instance a recombination type of lead-acid battery with C1 hour discharge rate about 120Ah (equals to 220Ah C20 "marketing rating") should be used accordingly. Therefore the EV overall consumption of particular low/mid voltage vehicle should not often exceed in this example 80-100% of this C1 hours rating — this applies for more advanced battery chemistries like Li-ion with slightly higher discharges C3-C5 as well. In this particular example, longevity of the lead-acid battery pack will be preserved by not discharging it in a prolonged or continuous regime above 120Ah currents.

The depth of discharge (DOD) is the recommended proportion of the total available energy storage for which that battery will achieve its rated cycles. Deep cycle lead-acid batteries generally should not be discharged below 50% capacity. More modern formulations can survive deeper cycles.

[[Image:1991.jpg|thumb|right|300px|Austria Solar 1991 (courtesy http://www.greenfleet.info)]]

In real world use some fleet RAV4-EVs have exceeded 100,000 miles (160,000 km) with little degradation in their daily range[http://www.evchargernews.com/miscfiles/sce-rav4ev-100k.pdf]. [[Jay Leno]]'s 1909 [[Baker Electric]] still operates on its original [[edison cells]]. Battery replacement costs may be partially or fully offset by the lack of regular maintenance such as oil and filter changes and by greater reliability due to fewer moving parts.

Critics claim that batteries pose a serious environmental hazard requiring significant disposal or recycling costs. Some of the chemicals used in the manufacture of advanced batteries such as [[Lithium ion battery|Li-ion]], [[Lithium ion polymer battery|Li ion polymer]] and [[Zinc-air battery|zinc-air]] are hazardous and potentially environmentally damaging. While these technologies are developed for small markets this is not a concern, but if production was to be scaled to match current car demand the risks might become unacceptable.

Supporters counter with the fact that traditional car batteries are one of the most successful [[recycling]] programs and that widespread use of battery electric vehicles would require the implementation of similar recycling regulations. More modern formulations also tend to use lighter, more biologically remediable elements such as iron, lithium, carbon and zinc. In particular, moving away from the heavy metals [[cadmium]] and [[chromium]] makes disposal less critical.

It is also not clear that batteries pose any greater risk than is currently accepted for fossil fuel based transport. Petrol and diesel powered transportation cause significant environmental damage in the form of spills, smog and distillation byproducts.

==Safety==
[[Firefighter]]s and rescue personnel receive special training to deal with the higher voltages encountered in electric and [[Hybrid Cars|hybrid]] gas-electric vehicle accidents.

==Future==
The future of battery electric vehicles depends primarily upon the availability of batteries with high energy densities, power density, long life, and reasonable cost as all other aspects such as motors, motor controllers, and chargers are fairly mature and cost competitive with ICE components.

The most likely future for BEVs currently appears to be the incremental improvements needed for [[Hybrid Cars|hybrids]]. [[Hybrid Cars|Hybrid]] EVs are a smaller step from purely ICE driven cars, yet share much of the same core technology as true BEVs. As [[Hybrid Cars|hybrids]] become more refined, battery life, capacity and energy density will improve and the combustion engine used less (particular with PHEV). At some point it may become economic for [[Hybrid Cars|hybrids]] to be sold without their ICE, finally leading to BEVs being commonplace.

Alternatively, if fuel cells make a breakthrough neither BEVs nor [[Hybrid Cars|hybrids]] will be required. More likely fuel cells will replace the ICE in [[Hybrid Cars|hybrid]] designs, providing a large energy density, whilst a more traditional battery pack provides the required power density.

[[Li-ion]], [[Lithium ion polymer battery|Li-poly]] and [[Zinc-air battery|zinc-air batteries]] have demonstrated energy densities high enough to deliver range and recharge times comparable to conventional vehicles. Their greater cost has discouraged use in commercial BEVs, but as production increases for other markets BEVs will no doubt use them.

[[Flywheel energy storage]] is a completely different form of electrical energy storage. It shares a lot with battery technologies and both batteries and flywheels are used in the same applications. Recent advances in materials and electronic control makes a flywheel 'BEV' a strong possibility. There have been prototype electric locomotives using flywheel storage.

[[Supercapacitor]] technology has not had the energy density per volume needed to be a small vehicle's primary energy storage but



==Fan's arguments==

The greatest fans of BEVs are those who have obtained or built and used them. This is a self-selected group because BEVs have not been promoted by the major manufacturers in the United States, so their enthusiasm may be misleading. Owners of conventional gasoline vehicles, once given the chance to live with an BEV often leave their gasoline cars sitting in the driveway. Spouses, luke warm when the vehicle is purchased often take over the vehicle from the purchaser once they use it. Fans point out the following:
* People can take responsibility for their own energy production with renewables. This will reduce dependence on foreign oil and large scale coal mining. Many electric vehicle owners and operators express great satisfaction in this aspect of electric vehicle use, even while acknowledging that this use can have only little effect on these matters unless adopted more widely and produced in greater quantities.
* Battery electric vehicles are quieter than ICE powered vehicles.
* BEVs do not produce noxious fumes around the car.
* If packs were mass-produced the charging time could be decreased by swapping the pack over with the charger. (This is not practical currently as the battery packs are far too heavy to handle without special tools)

==Sceptic's arguments==
Sceptics of the viability of BEV's fall into two groups, one arguing on "conventional" practical grounds and the other on practical grounds (often termed as idealistic) regarding the various problems of the car, in addition to tailpipe emissions. The former group points, among other issues, to the limited driving range available today between fillings. The other group ponders the [[future of the car]] as a transport solution for even mnore widesread global adoption, noting that the issues of traffic jams, noise pollution, total life-cycle pollution, energy expenditure and the health toll of a sedentary lifestyle, will not be solved by zero-emission vehicles.

==Controversy==
[[Image:ev1crushed.jpg|thumb|right|Stockpile of crushed EV1s|300px]]

In the USA, some EV fans have accused the three major domestic manufacturers, [[General Motors Corporation|General Motors]], [[Chrysler Corporation]] and [[Ford Motor Company]] of deliberately [[Sabotage|sabotaging]] their own electric vehicle efforts through several methods: failing to market, failing to produce appropriate vehicles, failing to satisfy demand, and using lease-only programs with prohibitions against end of lease purchase. By these actions they have managed to terminate their BEV development and marketing programs despite operators' offers of purchase and assumption of maintenance liabilities. They also point to the Chrysler "golf cart" program as an insult to the marketplace and to mandates, accusing Chrysler of intentionally failing to produce a vehicle usable in mixed traffic conditions. The manufacturers, in their own defense, have responded that they only make what the public wants. EV fans point out that this response is the same argument used by GM to justify the intensively promoted 11 mpg 6500 lb (2,950 kg) [[Hummer H2]] [[SUV]]. Of the various BEVs marketed by the "Big Three", only the [[General Motors EV1]] (manufactured by GM) and the [[Th!nk City]] (imported and marketed by Ford) came close to being appropriate configurations for a mass market. However, at the end of their programs GM destroyed its fleet, despite offers to purchase them by their drivers. Ford's Norwegian-built "Th!nk" fleet was covered by a three-year exemption to the standard U.S. Motor Vehicle Safety laws, after which time Ford had planned to dismantle and recycle its fleet; the company was, however, persuaded by activists to not destroy its fleet but return them to Norway and sell them as used vehicles. Ford also sold a few lead-acid battery [[Ford Ranger EV|Ranger EV]]s, and some fleet purchase [[Chevrolet|Chevrolet]] S-10 EV pickups are being refurbished and sold on the secondary market.

The three major American motor companies have almost exclusively promoted their electric cars in the American market, where gas is comparatively cheap, and virtually ignored the European market, where gas is significantly more expensive. This can be seen as avoiding the market. Because of the much higher fuel costs, the latent demand for electric vehicles would presumably be higher in Europe, and the outcome of increased BEV sales, in turn, be more certain.

Educational literature (for children) is still available that teaches that lead-acid batteries cannot store enough energy to make an electric vehicle practical. In itself true, this statement is a lie through omission, as it ignores more advanced battery designs.

Both Honda and Toyota also manufactured electric only vehicles. Honda followed the lead of the other majors and terminated their lease-only programs. Toyota offered vehicles for both sale and lease. While Toyota has terminated manufacture of new vehicles it continues to support those manufactured. It is actually possible to see a [[Toyota RAV4 EV|RAV-4 EV]] on the road but this is indeed a rare sight.

A film on the subject, directed by former EV1 owner and activist Chris Paine, entitled [[Who Killed the Electric Car?]] premiered at the [[Sundance Film Festival]] and at the [[Tribeca Film Festival]] in 2006, and is scheduled to premiere theatrically in June.

==United States==
[[Image:Detroit_Eletric_ad.jpg|thumb|right|1912 Detroit Electric]]
The [[United States]] produced many electric automobiles, such as the [[Detroit Electric]], during the early 20th century, but production dropped to insignificant numbers with the triumph of [[gasoline]] powered [[internal combustion engine]] vehicles in the [[1920s]]. A minor resurgence of interest in electric cars occurred in the late 1950s and early 1960s when Henney Coachworks built a limited run of their first (and only) electric car - the [[Henney Kilowatt]]. Even though the Henney Kilowatt never reached mass production numbers, the [[transistor]]-based electric technology developed for the Kilowatt paved the way for modern EVs.

In recent years, electric vehicles have been promoted through the use of tax credits. In [[California]], the California Air Resources Board attempted to set a quota for the use of electric cars, but this was withdrawn after complaints by auto manufacturers that the quotas were economically unfeasible due to a lack of consumer demand. However, many believe this complaint to be unwarranted due to the claim that there were thousands waiting to purchase or lease electric cars from companies such as [[General Motors Corporation|General Motors]], [[Ford Motor Company|Ford]], and [[Chrysler Corporation|Chrysler]] in which these companies refused to meet that demand despite their production capability. Others note that the original electric car leases were at reduced cost and the program could not be expected to draw the high volumes required without selling or renting the cars at a financial loss.
Since the California program was designed by the [[California Air Resources Board]] to reduce air pollution and not to promote electric vehicles, the zero emissions requirement in California was replaced by a combination requirement of a tiny number of [[zero-emissions vehicle]]s (to promote research and development) and a much larger number of [[partial zero-emissions vehicle]]s (PZEVs), which is an administrative designation for an ''super ultra low emissions vehicle'' ([[Super Ultra Low Emission Vehicle|SULEV]]), which emits pollution of about ten percent of that of an ordinary low emissions vehicle.

==Outside the United States==
In London, electrically powered vehicles are one of the categories of vehicle exempted from the [[London congestion charge|congestion charge]]. This is also true in all of [[Norway]], where zero-emission vehicles are also allowed to use the [[bus lane]]. In most cities of the [[United Kingdom]] low speed electric [[milk float]]s (milk trucks) are used for the home delivery of fresh [[milk]].

==Production vehicles==
Recent or current production battery electric vehicles sold or leased to fleets include:
*[[AC Propulsion tzero]] Very fast two-seat sportster prototype. Four produced.
*[[Anthony Electric]]
*[[Arton Birdie]]
*[[Baker Electric]]
*[[Bertone Blitz]]
*[[Citicar|Citicar/CommutaCar/Comuta-Van]]
*[[Citroën Berlingo|Citroën Berlingo Electrique]]
*[[Chevrolet S10 EV]] (Some sold to fleets, available on secondary market as refurbished vehicles) S-10 with [[General Motors EV1|EV1]] powertrain, over 100 produced only 45 sold to private owners and survived. Currently only [http://www.evbones.com/ EVbones] in Mesa AZ restores and converts to NiMH battery packs. 2005
*[[Chrysler TEVan]] (1993-1995) and Second Generation [[Chrysler TEVan|EPIC]] (1998-200?)
*[[Commuter Cars Tango]] Narrow, fast two seater (fore and aft.) Now accepting pre-orders in the US.
*[[Corbin Sparrow]] Three-wheeled, highway capable single-seat vehicle
*[[Detroit Electric]] (1907-1939)
*[[Elcat]] (1985-2002, almost all vehicles in second-hand use)
*[[Fiat Panda]] - Swis, Italy (2006).
*[[Ford Ranger EV]] (1998-2003) some sold, most leased. (Several hundred produced for lease only, almost all recovered and most destroyed) (Ford has announced reconditioning and sale of a limited quantity to former leaseholders by lottery)
*[[General Motors EV1]] Gen 1 (1996-1997), Gen II (1999-2003) (Over a thousand produced for lease only, all recovered and most destroyed)
*[[Global Electric Motorcars|Global Electric Motorcars, LLC. GEM]] Quite common in [[Davis, California]].
*[[Henney Kilowatt]] (1958-1960) The first modern (transistor-based) electric car, capable of highway speeds of up to 60mph and outfitted with modern hydraulic brakes. Fewer than 100 of them were produced before production was discontinued in 1960.
*[[Honda EV Plus]] (199?-1999) (Several hundred produced for lease only, all recovered and most destroyed)
*[[Hyundai SantaFe EV]] Currently testing fast charge in Hawaii 2005
*[http://www.hybridtechnologies.com/media.php?mediaID=060212 [[Hybrid Cars|Hybrid]] Tech & Mullen LiX-75 ] Announced in 2006, lithium-powered eco-sports car, estimated to be sold at $124,900
*[[Kewet]]
*[http://www.maranello4cycle.com/en/energia/sce.php Maranello 4cycle] — Italiano
*[[Nissan Altra]] Lithium-powered hatchback; never offered (even by lease) to consumers
*[[Porsche 550 Spyder replica electric conversion]]
*[[Peugeot 106 EV]]
*[[Peugeot Partner]]
*[[Pivco City Bee]]
*[[Renault Kangoo|Renault EV]] Kangoo
*[[Renault Twingo]] - Swiss, Italy (2006).
*[[REVA]] India-built city car (40 mph top speed,) now also sold in England as the "G-Whiz"
*[[Sebring-Vanguard Citicar]]
*[[Sinclair C5]]
*[[Solectria Force]] (Conversion, not currently in production)
*[[Tesla Motors]] See http://www.teslamotors.com/ also Business Week Article from BW May 8, 2006 http://www.businessweek.com/magazine/content/06_19/b3983077.htm?campaign_id=search
*[[Think City]] (Norwegian import by Ford, lease only, all recovered and returned to Norway)
*[[Toyota RAV4 EV]] (Rare, some leased and sold on U.S. East and west coast, out of production, supported) Toyota agreed to stop crushing
*[[Toyota Force]]
*[[Twike|TWIKE]] Three-wheeled EV with pedal assist option. Produced in Germany.
*[[Universal Electric Vehicle Corporation Electrum series Spyder, Com V-3]]
*[[Venturi Fetish|Venturi Fétish]] Marketed as the world's first electric sports two-seater. Monaco
*[[Zap]][http://www.zapworld.com] Imports to the USA in 2006 from China the [[Xebra]] electric car, an economy priced, enclosed three-wheel electric vehicle.
*[[Zebra Model Z roadster]] (Formerly Renaissance Tropica)
*[[Zytec Lotus Elise]]
*Phoenix motorcars, based in Ojai, CA, makes an electric car modeled on a 1930's Ford roadster.

==Prototypes==
Recent [[prototype]] EVs include:
*[[Eliica]] (Electric [[Battery Technology|LIthium-Ion]] Car) designed by a team at Keio University in Tokyo, led by Professor Hiroshi Shimizu.
*[[Cree SAM]]
*[[Ford E-Ka]]
*[[Lexus EV]] (Featured in the film ''[[Minority Report (movie)|Minority Report]]'')
*[[Pinanfarina Ethos II]]
*[[Renault EV Racer]]
*[[Solectria Sunrise]]
*[[Subaru Zero EV]] ([http://msnbc.msn.com/id/8995780/ announcement])
*[[Suzuki EV Sport]]
*[[Maya-100]] Battery: Li-ion "super"-polymer; claimed range: 360 km [http://www.electrovaya.com/innovation/zev_tech.html]
*[[Mitsubishi Colt EV]] (Li-ion battery, in-wheel motors [http://media.mitsubishi-motors.com/pressrelease/e/corporate/detail1269.html])
*[[Volvo 3CC]] Three seater with lithium ion batteries [http://volvocars-pr.com/index.asp?par=conceptcars&pag=overview&model=194&lang=1&flash=0]
*[[Electric Scooter]] Razor Electric Bikes [http://www.electric-scooters-galore.com]

==Production announcements==
*Venturi "Fetish" sports car to use AC propulsion components [http://www.venturi.fr/us/fetish/specs/specs.php3] (Flash animation with music background)
**[http://www.forbes.com/vehicles/2004/10/05/cx_dl_1005vow.html Forbes — Vehicle of the Week — Car Fetish]
*AC propulsion announces plans to convert [[Scion (car)|Toyota Scion]] xA and xB vehicles[http://www.acpropulsion.com/ACP_FAQs/FAQ_cars.htm] (items 8 and 9).
*[[Mitsubishi]], a [[Japan|Japanese]] automobile manufacturer, announced on [[May 11]] [[2005]] that it will mass-produce its MIEV (Mitsubishi In-wheel Electric Vehicle.) Test fleets are to arrive in 2006 and production models should be available in 2008. [http://abcnews.go.com/Business/wireStory?id=746971&page=1]. The first test car, revealed to be [[Mitsubishi Colt EV|Colt EV]], is expected to have a range of 93 miles using [[Battery Technology|lithium-ion]] batteries and in-wheel electric motors. The target price of a MIEV should be around [[United States dollar|US$]]19,000. No export decision has yet been made. [http://www.msnbc.msn.com/id/7816102/].
* [[Plug-in hybrid electric vehicle]] are being developed by calcars, Edrive Systems, and Hymotion. They take a Toyota Prius, add more battery capacity and modify the controller. Then they can get 250 mpg by plugging in at home for a small light charge each night. Edrive and Hymotion recently announced plans to modify other [[Hybrid Cars|hybrid]] models, including the Ford Escape. http://www.calcars.org/
*SVE (Société de Véhicules Électric, a company formed by the French Dasseault and Heuliez group) announced they will produce the [http://www.cleanova.com/public/sve/ Cleanova II] (French only), based on the Kangoo. It will be available in pre-mass-production in 2007 and mass-production in 2008. The system exists in two versions: all electric (200km autonomy) and rechargeable [[Hybrid Cars|hybrid]] (500km autonomy). The system include an electric engine developed by [http://www.tm4.com TM4] a subsidiary of Hydro-Quebec, from Quebec Canada who developed also since 20 years an [http://en.wikipedia.org/wiki/User:A-Hrafn/Wheel_motor electric wheel motor].

==Hobbyists, research, and racing==
There is a minor industry supporting the [[electric vehicle conversion|conversion]] and building of BEVs by hobbyists. Some designers point out that a specific type of electric vehicle offers comfort, utility and quickness, sacrificing only range. This is called a short range electric vehicle. This type may be built using high performance lead–acid batteries, but of only about half the mass that would be expected to obtain a 60 to 80 mile (100 to 130 km) range. The result is a vehicle with about a thirty mile (50 km) range, but when designed with appropriate weight distribution (40/60 front to rear) does not require power steering, offers exceptional acceleration in the lower end of its operating range, is freeway capable and legal, and costs less to build and maintain. By including a manual transmission this type of vehicle can obtain both better performance ''and'' higher efficiency than the single speed types developed by the major manufactures. Unlike the converted golf carts used for [[neighborhood electric vehicle]]s, these may be operated on typical suburban throughways (40 to 45 mph or 60 or 70 km/h speed limits are typical) and can keep up with traffic typical to these roads and to the short on and off segments of freeways that are common in suburban areas.

Aside from production electric cars, often hobbyists build their own EVs by [[Electric vehicle conversion|converting]] existing production cars to run solely on electricity. Some even drag race them as members of [[NEDRA]]. Universities such as the [[University of California, Irvine]] even go so far as to build their own custom electric or [[Hybrid Cars|hybrid]]-electric cars from scratch.

A non-profit program "CalCars"[http://www.calcars.org/] at the University of California, Davis, is attempting to convert a [[Hybrid Cars|hybrid]] [[Toyota Prius]] automobile to operate as a [[plug-in hybrid electric vehicle]] (PHEV) through the installation of additional batteries and software modifications. Such a vehicle will operate as would a pure electric for short trips, taking its power from household and workplace rechargers. For longer trips the vehicle will operate as it does at present—as a "strong" [[Hybrid electric vehicle|hybrid vehicle]]. A prototype (using sealed lead-acid batteries) is undergoing tests. It is expected that a production conversion would use a more advanced battery. (Advanced batteries are under development and soon for production in the support of [[Hybrid Cars|hybrid vehicles]].) They are currently soliciting donations of additional vehicles and funds for this project.

Battery electric vehicles are also highly popular in quarter mile (400 m) racing. The National Electric Drag Racing Association regularly holds electric car races and often competes them successfully against exotics such as the [[Dodge Viper]].
[[Image:Eliica.jpg|thumb|right|250px|Eliica prototype]]
*Japanese Prof. Dr. Hiroshi Shimizu from Faculty of Environmental Information of the Keio University created the limousine of the future: the '''Eliica (Electric Lithium Ion Car)''' has 8 wheels with electric 55 kW hub motors (8WD) with an output of 470 kW and zero emissions. With a top speed of 190 km/h and a maximum reach of 320 km provided by [[Battery Technology|lithium-ion]]-batteries. See the video at [http://www.eliica.com]
*German ''Umweltbrief'' [http://www.umweltbrief.de/neu/html/save.the.planet.int.html] want to convert an old-timer car into full electric drive with 4 wheel hub motors; a retro car for the 21th century called '''electro4'''. This drive is nearly free of abrasion and maintenance and very reliable. Further advantages are optimal capability of acceleration and best traction through individual control of the wheels. Also the power is generated in the place where its used. Gearbox, kardan shaft and drive shaft become unnecessary, which means less weight. Even an old car can get a [[torque]] of 1000 [[newton metre|N·m]]. This [[Four Wheel Drive|4WD]] is very silent. There is no vibration and no motor cold-running, the full energy is available immediately. Also small cars can get this system. All is combinable with anti-block system, anti-slip system, stability system, etc., climate control with a/c, heating/cabin, pre-conditioning etc. [http://www.umweltbrief.de/neu/html/electro4.html]

==See also==
*[[Electric boat]]
*[[Electric scooter]]
*[[Electric vehicle]]
*[[Electric vehicle conversion]]
*[[Electric vehicle production]]
*[[Golf cart]]
*[[Hybrid vehicle]]

==Patents==
* {{US patent|772571}}, [[Hiram Stevens Maxim]], ''Electric motor vehicle''
* {{US patent|594805}}, H. S. Maxim, ''Motor vehicle''
* {{US patent|523354}}, E. E. Keller, ''Electrically Propelled Preambulator''

==References==
<references />

==External links==
* [http://www.eaaev.org/ Electric Auto Association]
* [http://www.electriccarsociety.com Electric Car Society]

===EV news stories===
* [http://www.pbs.org/now/shows/223/index.html NOW on PBS] has a streaming interview with Chris Paine, who directed "Who Killed the Electric Car", as well as an electric car timeline, insight from a transportation expert about fuel alternatives, and an interview with EC enthusiast/former Baywatch actress Alexandra Paul: "When the Exxon Valdez spilled in 1989, I was angry. And then I said to myself, 'Hey Alexandra, you're part of the problem -- you're buying gas.' And that's when I decided I didn't want to be a part of the problem, so I bought my first electric car a few months later."
* San Francisco Chronicle: [http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/04/24/MNGDTCEA9B1.DTL Owners charged up over electric cars, but manufacturers have pulled the plug] [[24 April]] [[2005]]
* [http://www.pbs.org/pov/borders/2004/air/index.html The Air We Breathe, The Cars We Drive], 2004
* [http://www.washingtonpost.com/ac2/wp-dyn/A61508-2003Oct21?language=printer The Electric-Car Slide], [[October 22]] [[2003]]
* [http://www.cbsnews.com/stories/2003/10/01/earlyshow/main576116.shtml Slim Fit For The Freeways] [[2 October]] [[2003]]



[[Category:Alternative propulsion]]
[[Category:Automobiles]]
[[Category:Automotive technologies]]
[[Category:Electric vehicles|*]]
[[Category:Green vehicles]]

[[cs:Elektromobil]]
[[de:Elektroauto]]
[[fr:Véhicule électrique]]
[[ja:電気自動車]]
[[ru:Электромобиль]]

File:Ford500autotrans.JPG

2006-06-27T23:21:26Z

Philip rosenblum:

Automatic transmission

2006-06-27T23:20:39Z

Philip rosenblum:

{{transmission types}}
An '''automatic transmission''' is an [[automobile]] [[gearbox]] that can change [[gear ratio]]s automatically as the car or truck moves, thus freeing the driver from having to shift gears [[manual transmission|manually]]. (Similar but larger devices are also used for [[railroad]] [[Locomotive#Diesel-hydraulic|locomotives]].)

Most cars sold in the [[United States]] since the [[1950s]] have been equipped with an automatic transmission. This has, however, not been the case in [[Europe]] and much of the rest of the world. Automatic transmissions, particularly earlier ones, reduce [[fuel efficiency]] and power. Where fuel is expensive and, thus, engines generally smaller, these penalties are more burdensome. In recent years, automatic transmissions have significantly improved in their ability to support high fuel efficiency but [[manual transmission]]s are still generally more efficient. (This balance may finally shift with the introduction of practical [[continuously variable transmission]]s; see below.)

Most automatic transmissions have a set selection of possible gear ranges, often with a [[parking pawl]] feature that will lock the output shaft of the transmission.

However, some simple machines with limited speed ranges and/or fixed engine speeds only use a [[torque converter]] to provide a variable gearing of the engine to the wheels. Typical examples include [[forklift]] trucks and some modern [[lawn mower]]s.

Recently manufacturers have begun to make '''[[continuously variable transmission]]s''' available. These designs can change the ratios over a range rather than between set gear ratios. Even though prototypes for CVT have been around for decades, it is just now reaching commercial practicability.

==Hydraulic automatic transmissions==
[[Image:Ford500autotrans.JPG|frame|right|The automatic transmission selector lever in a [[Ford Five Hundred]] car.]]
The predominant form of automatic transmission is [[hydraulic|hydraulically]] operated, using a [[fluid coupling]] or [[torque converter]] and a set of [[epicyclic gearing|planetary gearsets]] to provide a range of torque multiplication.

===Parts and operation===
A hydraulic automatic transmission consists of the following parts:
*''[[Fluid coupling]]'' or ''[[Torque converter]]'': A hydraulic device connecting the engine and the transmission. It takes the place of a mechanical [[clutch]], allowing the engine to remain running at rest without stalling. A torque converter is a fluid coupling that also provides a variable amount of torque multiplication at low engine speeds, increasing "breakaway" acceleration.
*''[[Epicyclic gearing|Planetary gearset]]'': A compound planetary set whose bands and clutches are actuated by hydraulic [[servo]]s controlled by the valve body, providing two or more gear ratios.
*''Valve body'': A hydraulic control center that receives pressurised fluid from a ''main pump'' operated by the fluid coupling/torque converter. The pressure coming from this pump is regulated used to run a network of spring-loaded valves, check balls and [[servo]] pistons. The valves use the pump pressure and the pressure from a [[centrifugal governor]] on the output side (as well as hydraulic signals from the range selector valves and the ''throttle valve'' or ''modulator'') to control which ratio is selected on the gearset; as the car and engine change speed, the difference between the pressures changes, causing different sets of valves to open and close. The hydraulic pressure controlled by these valves drives the various clutch and brake band actuators, thereby controlling the operation of the planetary gearset to select the optimum gear ratio for the current operating conditions. However, in many modern automatic transmissions, the valves are controlled by electro-mechanical servos which are controlled by the Engine Management System or a separate [[Transmission Control Unit|transmission controller]]. (See [[#History and improvements|History and improvements]] below.)

The multitude of parts, and the complex design of the valve body originally made hydraulic automatic transmissions much more complicated (and expensive) to build and repair than manual transmissions. In most cars (except US family, luxury, sport-utility vehicle, and minivan models) they have usually been extra-cost options for this reason. Mass manufacturing and decades of improvement have reduced this cost gap.

===History and improvements===
[[Oldsmobile]]'s [[1940]] models featured [[Hydra-Matic]] drive, the first mass-production fully automatic transmissions. Initially an Olds exclusive, Hydra-Matic had a [[fluid coupling]] (not a torque converter) and three planetary gearsets providing four speeds plus reverse. Hydra-Matic was subsequently adopted by [[Cadillac]] and [[Pontiac]], and was sold to various other automakers, including [[Bentley Motors Limited|Bentley]], [[Hudson Motor Car|Hudson]], [[Kaiser Motors|Kaiser]], [[Nash Motors|Nash]], and [[Rolls-Royce Limited|Rolls-Royce]]. From [[1950]] to [[1954]] [[Lincoln (automobile)|Lincoln]] cars were also available with GM Hydra-Matic. [[Mercedes-Benz]] subsequently devised a four-speed fluid coupling transmission that was similar in principle to Hydra-Matic, but did not share the same design.

The first torque converter automatic, [[Buick]]'s [[Dynaflow]], was introduced for the [[1948]] model year. It was followed by [[Chevrolet]]'s [[Powerglide]] and Packard's [[Ultramatic]] for the [[1950]] model year. Each of these transmissions had only two forward speeds, relying on the torque converter for additional gear reduction.

In the early [[1950s]] [[Borg-Warner]] developed a series of three-speed torque converter automatics for [[Ford Motor Company]], [[Studebaker]], and several foreign and independent makes.

[[Chrysler Corporation|Chrysler]] was late in developing its own true automatic, introducing the two-speed torque converter [[PowerFlite]] in [[1953]] and the three-speed [[TorqueFlite]] in [[1956]].

By the late [[1960s]] most of the fluid-coupling four-speeds and two-speed transmissions had disappeared in favor of three-speed units with torque converters. By the early [[1980s]] these were being supplemented and eventually replaced by [[overdrive (mechanics)|overdrive]]-equipped transmissions providing four or more forward speeds. Many transmissions also adopted the lock-up torque converter (a mechanical clutch locking the torque converter impeller and turbine together to eliminate slip at cruising speed) to improve fuel economy.

As the [[electronic control unit|engine computer]]s became more and more capable, even more of the valve body's functionality was offloaded to them. These transmissions, introduced in the late 1980s and early 1990s, remove almost all of the control logic from the valve body, and place it in into the engine computer. (Some manufacturers use a separate computer dedicated to the transmission but sharing information with the engine management computer.) In this case, [[solenoid]]s turned on and off by the computer control shift patterns and gear ratios, rather than the spring-loaded valves in the valve body. This allows for more precise control of [[shift point]]s and shift quality, and (on some newer cars) also allows semi-automatic control, where the driver tells the computer when to shift. The result is an impressive combination of efficiency and smoothness. Some computers even identify the driver's style and adapt to best suit it.

[[ZF Friedrichshafen AG]] and [[BMW]] were responsible for introducing the first five-speed automatic (the [[ZF 5HP18 transmission|ZF 5HP18]] in the 1992 [[BMW]] [[BMW E34|E34]] [[BMW 5-Series|5-Series]]) and the first six-speed (the [[ZF 6HP26 transmission|ZF 6HP26]] in the 2002 [[BMW]] [[BMW E65|E65]] [[BMW 7-Series|7-Series]]). [[Mercedes-Benz]]'s [[7G-TRONIC]] was the first seven-speed in 2003, with [[Toyota Motor Company]] introducing an 8-speed in 2007 on the [[Lexus LS]].

== Automatic Transmission Models ==
Some of the best known automatic transmission families include:
* [[List of GM transmissions|General Motors]] — [[Powerglide]], [[Turbo-Hydramatic]] 350 and 400, [[GM 4L60-E transmission|4L60-E]], [[GM 4L80-E transmission|4L80-E]]
* [[List of Ford transmissions|Ford]]: [[Cruise-O-Matic]], [[Ford C4 transmission|C4]], [[Ford C6 transmission|C6]], [[Ford AOD transmission|AOD/AODE]], [[Ford E4OD transmission|E4OD]], [[Ford ATX transmission|ATX]], [[Ford AXOD transmission|AXOD/AX4S/AX4N]]
* [[List of Chrysler transmissions|Chrysler]]: [[TorqueFlite]] 727 and 904, A500, A518, 45RFE, 545RFE
* [[BorgWarner]] (later [[Aisin AW]])
* [[List of ZF transmissions|ZF Friedrichshafen AG]]
* [[Allison Transmission]]
* [[Voith Turbo]]
* [[List of Aisin transmissions|Aisin AW]]; Aisin AW is a Japanese automotive parts supplier, known for its automatic transmissions and navigation systems
* [[List of Honda transmissions|Honda]]
* [[List of Jatco transmissions|Nissan/Jatco]]

Automatic transmission families are usually based on [[Ravigneaux]], [[Lepelletier]], or [[Simpson]] [[planetary gear]]sets. Each uses some arrangement of one or two central sun gears, and a ring gear, with differing arrangements of planet gears that surround the sun and mesh with the ring. An exception to this is the [[Hondamatic]] line from [[Honda]], which uses sliding gears on parallel axes like a manual transmission without any planetary gearsets. Although the Honda is quite different from all other automatics, it is also quite different from an automated manual transmission.

==Continuously variable transmissions==
{{main|continuously variable transmission}}

A different type of automatic transmission is the ''continuously variable transmission'' or ''CVT'', which can smoothly alter its [[gear ratio]] by varying the diameter of a pair of [[belt (mechanical)|belt]] or [[roller chain|chain]]-linked [[pulley]]s, [[wheel]]s or [[cone (mechanical)|cone]]s. Some continuously variable transmissions use a [[hydrostatic drive]] consisting of a [[variable displacement pump]] and a hydraulic motor to transmit power without gears. CVT designs are usually as fuel efficient as manual transmissions in city driving, but early designs lose efficiency as engine speed increases.

A slightly different approach to CVT is the concept of ''[[toroidal CVT]]'' or ''[[Continuously variable transmission#infinitely variable transmission|IVT]]'' (from infinitely variable transmission). These concepts provide zero and reverse gear ratios.

Some current hybrid vehicles, notably those of [[Toyota]], [[Lexus]] and [[Ford Motor Company]], have an "electronically-controlled CVT" ([[E-CVT]]). In this system, the transmission has fixed gears, but the ratio of wheel-speed to engine-speed can be continuously varied by controlling the speed of the third input to a [[differential]] using an [[electric motor]]-[[generator]].

==Manually controlled automatic transmissions==
Most automatic transmissions offer the driver a certain amount of manual control over the transmission's shifts (beyond the obvious selection of forward, reverse, or neutral). Those controls take several forms:
* ''Throttle kickdown'': Most automatic transmissions include a switch on the throttle linkage that will force the transmission to downshift into the next lower ratio if the throttle is fully engaged. The switch generally only functions up to a certain road speed, so as to prevent a downshift that would overrev the engine. Some transmissions also had a part-throttle kickdown, obviating the need to "floorboard" the throttle to downshift.
* ''Low gear ranges'': Many transmissions have switches or selector positions that allow the driver to limit the maximum ratio that the transmission may engage. On older transmissions, this was accomplished by a mechanical lockout in the transmission valve body preventing an upshift until the lockout was disengaged; on computer- controlled transmissions, the same effect is accomplished electronically. The transmission can still upshift and downshift automatically between the remaining ratios: for example, in the ''3'' range, a transmission could shift from first to second to third, but not into fourth or higher ratios. Some transmissions will still upshift automatically into the higher ratio if the engine reaches its maximum permissible speed in the selected range.
* ''Manual controls'': Some transmissions have a mode in which the driver has full control of ratio changes (either by moving the selector or through the use of buttons or paddles), completely overriding the hydraulic controller. Such control is particularly useful in cornering, to avoid unwanted upshifts or downshifts that could compromise the vehicle's balance or traction. "Manumatic" shifters, first popularized by [[Porsche]] in the [[1990s]] under the [[trade name]] [[Tiptronic]], have become a popular option on [[sports cars]] and other performance vehicles. With the near-universal prevalence of electronically controlled transmissions, they are comparatively simple and inexpensive, requiring only software changes and the provision of the actual manual controls for the driver. The amount of true manual control provided is highly variable: some systems will override the driver's selections under certain conditions, generally in the interest of preventing engine damage.

Some automatic transmissions modified or designed specifically for [[drag racing]] may also incorporate a transmission brake, or "trans-brake," as part of a manual valve body. Activated by electrical solenoid control, a trans-brake simultaneously engages the first and reverse gears, locking the transmission and preventing the input shaft from turning. This allows the driver of the car to raise the engine rpm against the resistance of the torque converter, then launch the car by simply releasing the trans-brake switch.

==External links==
*[http://auto.howstuffworks.com/automatic-transmission.htm How Automatic Transmissions Work] on [[HowStuffWorks]]
*[http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US5370589&F=0| US5370589 Lepelletier's concept is shown on this patent]
*[http://www.toomonline.com/gearboxlinks.htm Randolph Toom webpage] — a survey of current automatic transmissions
*[http://www.torotrak.com Articles related to IVT]
*[http://www.allisontransmission.com Allison Transmission Website]
*[http://www.powertraincontrolsolutions.com PCS Automatic Transmission Controller Website]

[[Category:Automotive transmission technologies]]
[[Category:Auto parts]]

[[es:Transmisión automática]]
[[fr:Cotal]]
[[it:Cambio automatico]]
[[ja:オートマチックトランスミッション]]
[[nl:Volautomatische versnellingsbak]]
[[no:automatgir]]

File:KyotoTaxiRide.jpg

2006-06-27T23:16:42Z

Philip rosenblum:

Automotive navigation system

2006-06-27T23:15:40Z

Philip rosenblum:

[[Image:KyotoTaxiRide.jpg|thumb|right|250 px|A [[Taxicab|taxi]] in [[Kyoto]], equipped with GPS navigation system]]
An '''automotive [[Navigation System|navigation system]]''' is a [[satellite navigation system]] designed for use in [[automobiles]]. Unlike other [[GPS]] systems, these use position data to locate the user on a [[road]] in the unit's map [[database]]. Using the road database, the unit can give directions to other locations along roads also in its database. [[Dead reckoning]] using distance data from sensors attached to the [[drivetrain]] and a [[Inertial guidance system#Vibrating gyros|gyroscope]] can be used for greater reliability, as [[Navigation System|GPS]] signal loss and/or [[multipath]] can occur due to [[urban canyon]]s or [[tunnels]].

==History==
[[Honda]] claims[http://world.honda.com/history/challenge/1988navigationsystem/index.html] to have created the first [[Navigation System|navigation system]] starting in 1983, and culminating with general availability in the 1990 [[Acura Legend]]. This [[analog computer|analog]] system used an [[accelerometer]] to judge location, as the [[GPS]] system was not yet generally available.

[[Pioneer Corporation|Pioneer]] claims[http://www.pioneer.co.uk/uk/content/company/company/history.html] to be the first with a [[Navigation System|GPS]]-based auto [[Navigation System|navigation system]], in [[1990]].

==Visualization==
[[Navigation System|Navigation]] systems use a combination of:
* top view for the map
* top view for the map with the map rotating like the automobile
* [[bird's-eye view]] for the map or the next curve
* linear gauge for distance, which is redundant, if a rotating map is used
* numbers for distance

==Road database==
===Contents===
The road database is a [[vector map]] of some area of interest. Street names or numbers and house numbers are encoded as [[geographic coordinate]]s so that the user can find some desired destination by street address. [[Point of interest|Points of interest]] will also be stored with their geographic coordinates.

Contents can be produced by the user base as their cars drive along existing streets and communicating via the internet, yielding a free and up to date map.

===Format===
Formats are uniformly proprietary; there is no industry standard for satellite [[Navigation System|navigation]] maps.
The map vendors [[Tele Atlas]] and [[NAVTEQ]] create the base map in a standard format [[Geographic Data Files|GDF]] but each electronics manufacturer compiles it in an optimised format.

===Media===
The road database may be stored in [[Read-only memory|solid state read-only memory (ROM)]], optical media ([[CD]] or [[DVD]]), solid state [[flash memory]], magnetic media ([[hard disk]]), or a combination. A common scheme is to have a [[base map]] permanently stored in ROM which can be augmented with detailed information for a region the user is interested in. A ROM is always programmed at the factory; the other media may be preprogrammed, or [[download]]ed from a [[CD]] or [[DVD]] via a [[computer]].

==Other functions==
*Many systems can give information on nearby services such as [[restaurants]], [[cash machine]]s and [[gas station]]s.
*Some newer systems can not only give precise driving directions, they can also receive and display information on [[traffic congestion map|traffic congestion]] and suggest alternate routes. This may use either [[Traffic Message Channel|TMC]], which delivers coded traffic information using [[Radio Data System|RDS]] or [[satellite radio]], or an [[Internet]] link to a provider's server using technology such as [[GPRS]] through the user's [[mobile phone]].
*The color [[LCD]] screens on some automotive [[Navigation System|navigation]] systems can also be used to display [[television]] broadcasts or [[DVD]] [[Film|movie]]s.
* A few systems integrate with [[mobile phone]]s for handsfree talking and [[SMS|SMS messaging]].
* [[Navigation System|GPS]] replaces the radio-dispatch of some taxicabs in Taiwan and Singapore. The location of every cab is known to the central dispatch computer, and when a cab is needed somewhere, the computer automatically selects the closest cab to answer the call. The system can also automate calls to the customer when the cab arrives and waits for the customer.

==Example Systems==
*[[Dynavix|Dynavix Mobile]]
*[[Etak]]
*[[Garmin]] StreetPilot
*[[Gizmondo]]
*[[The Hertz Corporation#Hertz Neverlost|Hertz Neverlost]]
*[[iCN GPS|Navman iCN series]]
*[[http://www.telenav.com/ TeleNav]]
*[[TomTom (company)|TomTom]]
*[[Pioneer Corporation|Pioneer]]

==See also==
*[[Mobile data terminal]]
*[[Global Positioning System]]

[[Category:GPS]]
[[Category:navigation]]
[[Category:automotive technologies]]
[[Category:Auto parts]]

[[de:Navigations-System]]
[[nl:Routenavigatiesysteem]]
[[tr:Yol bilgisayarı]]

File:2005 winter road full beam and extra lights.jpg

2006-06-27T23:11:38Z

Philip rosenblum:

File:2005 winter road full beam.jpg

2006-06-27T23:11:27Z

Philip rosenblum:

File:2005 winter road dipped beam.jpg

2006-06-27T23:11:16Z

Philip rosenblum:

File:SequentialTurnSignal.gif

2006-06-27T23:10:59Z

Philip rosenblum:

Automotive lighting

2006-06-27T23:07:36Z

Philip rosenblum:

The [[light]]ing system of a [[motor vehicle]] consists of lighting and signalling devices mounted or integrated to the front, sides and rear of the vehicle. The purpose of this system is to provide illumination by which for the driver to operate the vehicle safely after dark, to increase the conspicuity of the vehicle, and to display information about the vehicle's presence, position, size, direction of travel and intended travel, and brake status.

==Forward illumination==
Forward illumination is provided by main- ("high") and dipped- ("low") beam [[headlamp]]s, which may be augmented by fog lamps and/or driving lamps.

===Dipped (low, passing, meeting)-beam headlamps===
{{main|Headlamp}}
[[Image:2005_winter_road_dipped_beam.jpg|thumb|right|E-code dipped/low beam]]
Dipped-beam (low-beam, passing-beam, meeting-beam) headlamps provide a distribution of light designed to provide adequate forward and lateral illumination with limits on light directed towards the eyes of other road users, to control glare. This beam is intended for use whenever other vehicles are present ahead. The international [[ECE Regulations]] specify a beam with a sharp, asymmetric cutoff preventing significant amounts of light from being cast into the eyes of drivers of preceding or oncoming cars. Control of glare is less strict in the North American [[Society of Automotive Engineers|SAE]] beam standard contained in [[Federal Motor Vehicle Safety Standard 108|FMVSS / CMVSS 108]].

===Main (high, driving)-beam headlamps===
{{main|Headlamp}}
[[Image:2005_winter_road_full_beam.jpg|thumb|right|European E-code high/full beam]]
Main-beam (high-beam, driving-beam) headlamps provide a bright, centre-weighted distribution of light with no especial control of light directed towards other road users' eyes. As such, they are only suitable for use when alone on the road, as they will dazzle other drivers. International ECE Regulations permit higher-intensity high-beam headlamps than are allowed under [[Federal Motor Vehicle Safety Standard 108|North American regulations]].

===Driving lamps===
[[Image:2005_winter_road_full_beam_and_extra_lights.jpg|thumb|right|High/full beam augmented by auxiliary lights]]
"Driving lamp" is an obsolete term most often used to refer to auxiliary high-beam headlamps. They are most notably fitted on [[rally]]ing cars, and are occasionally fitted to production vehicles derived from or imitating such cars. They are common in countries with large stretches of unlit roads, or in regions such as the [[Nordic countries]] where the period of daylight is short during winter.

===Front fog lamps===
Fog lamps provide a wide, bar-shaped beam of light with a sharp cutoff at the top, and are generally aimed and mounted low. They may be either white or [[selective yellow]]. They are intended for use at low speed to increase the illumination directed towards the road surface and verges in conditions of poor visibility due to rain, fog, dust or snow. As such, they are often most effectively used in place of dipped-beam headlamps, reducing the glareback from fog or falling snow (although use without headlamps may not be permitted in some countries ).

Use of the front fog lamps when visibility is not seriously reduced is often prohibited (for example in the [[United Kingdom]]), as they can cause increased glare to other drivers, particularly in wet pavement conditions, as well as [http://www.danielsternlighting.com/tech/lights/fog_lamps/fog_lamps.html harming the driver's own vision due to excessive foreground illumination].

The respective purposes of front fog lamps and driving lamps are often confused, due in part to persistent misapprehension by the public at large that fog lamps are necessarily [[selective yellow]], while any auxiliary lamp that makes [[white]] light is a driving lamp. Automakers and aftermarket parts and accessories suppliers frequently refer interchangeably to "fog lamps" and "driving lamps" (or "fog/driving lamps"). In most countries, weather conditions necessitating their use are very rare, and there is no legal requirement for them, so their primary purpose is frequently cosmetic. Studies have [http://www.sae.org/servlets/productDetail?PROD_TYP=PAPER&PROD_CD=970657 shown more people inappropriately use their fog lamps in dry weather] than use them properly in poor weather in North America.

===Cornering lamps===
On some models in North America, front white "cornering lamps" provide extra lateral illumination in the direction of an intended turn. These are actuated in conjunction with the turn signals, though they burn steadily. These have traditionally been prohibited under international UN/ECE regulations, though provisions have recently been made to allow them as long as they are only operable when the vehicle is travelling at less than 40 [[kilometres per hour]].

==Conspicuity==

===Front position lamps (parking lamps)===
Nighttime standing-vehicle conspicuity to the front is provided by front position lamps, known as "parking lamps" or "parking lights" in North America; "sidelights" in UK English, and in other regions as "position lamps," "standing lamps," or "city lights". Despite the UK term, these are not the same as ''sidemarker lights'' described below. These lamps may emit white or amber light in North America; elsewhere in the world they must emit white light only. The "City light" terminology for front position lamps comes from the now-obsolete practice, formerly adhered to in cities like Moscow, London and Paris, of driving at night in built-up areas using these low-[[luminous intensity|intensity]] lights rather than headlamps. Today, it is illegal in most countries to drive a vehicle with parking lamps illuminated, unless the headlamps are also illuminated. The UK briefly required [[Daytime running lamp#Great Britain|Dim-Dip lights]] as an attempt to optimize the level of light used at night in built-up areas.

Since the late 1960s, front position lamps have been required to remain illuminated even when the headlamps are on, to maintain the visual signature of a dual-track vehicle to oncoming drivers in the event of headlamp burnout. Front position lamps worldwide produce between 4 and 125 [[candela]].

In Germany, the [[StVZO]] (Road Code) requires a different function also known as "parking lamps": With the vehicle's ignition switched off, the operator may activate a low-intensity light at the front (amber or white) and rear (red) on either the left or the right side of the car. This function is used when parking in narrow unlit streets to provide parked-vehicle conspicuity to those driving past. This function is served passively and without power consumption in North America by the mandatory sidemarker retroreflectors.

===Dim-Dip Lamps (UK Only)===
UK regulations briefly required vehicles first used on or after 1 April 1987 to be equipped with [http://http://dastern.torque.net/techdocs/dimdip.html a '''dim-dip''' device] or daytime running lamps, except such vehicles as comply fully with [[World Forum for Harmonization of Vehicle Regulations|ECE Regulation 48]] regarding installation of lighting equipment. A dim-dip device operates the low beam headlamps (called "dipped beam" in the UK) at between 10 percent and 20 percent of normal low-beam intensity. UK DRLs must emit at least 200 candela straight ahead, and no more than 800 candela in any direction. In practise, most vehicles were equipped with the dim-dip option, rather than DRLs.

The dim-dip systems were not intended for daytime use as [[Daytime Running Lamp|DRLs]]. Rather, they operated if the engine was running ''and'' the driver switched on the parking lamps (called "sidelights" in the UK). Dim-dip was intended to provide a nighttime "town beam" with intensity between that of parking lamps (commonly used by British drivers in city traffic after dark) and dipped/low beams, because the former were considered insufficiently intense to provide improved [[conspicuity]] in conditions requiring it, while the latter were considered too glaring for safe use in built-up areas. The UK was the only country to use such dim-dip systems.

In 1988, the European Commission successfully prosecuted the UK government in the European Court of Justice, arguing that the UK requirement for dim-dip was illegal under EC directives prohibiting member states from enacting vehicle lighting requirements not contained in pan-European EC directives. As a result, the UK requirement for dim-dip was quashed. Nevertheless, dim-dip was (and is) still permitted, and while such systems are not presently as common as they once were, dim-dip functionality was fitted on many new cars well into the 1990s.

===Rear position lamps (tail lamps)===
Nighttime vehicle conspicuity to the rear is provided by red rear taillamps (properly: "rear position lamps") and red rear-facing [[retroreflector]]s.

===Rear registration plate lamp===
The rear [[registration plate]] must be illuminated by a white lamp whenever the position lamps are active.

===Sidemarker lights and retroreflectors===
In North America, amber front and red rear sidemarker lamps and retroreflectors are required. The law initially required lights '''or''' retroreflectors on vehicles made after [[1 January]] [[1968]]. This was amended to require lights '''and''' retroreflectors on vehicles made after [[1 January]] [[1970]]. These side-facing devices make the vehicle's presence, position and direction of travel clearly visible from oblique angles. The lights are wired so as to illuminate whenever the vehicles parking and taillamps are on, including when the headlamps are being used. Front amber sidemarkers in North America may or may not be [http://www.danielsternlighting.com/tech/markerflash/markerflash.html wired so as to flash with the turn signals].

Sidemarkers are permitted outside North America, but not required. If installed, they are required to be brighter and visible through a larger horizontal angle than US sidemarkers, they may not flash, and they must be amber at the front and rear unless the rear sidemarker is incorporated into the main rear lamp cluster, in which case it may be red or amber. Some Japanese, European, British and US-brand vehicles have sidemarkers in Europe and other countries where they are not required.

[[Japan|Japan's]] recent accession to internationalized [[ECE Regulations]] caused automakers to change the rear sidemarker colour from red to amber on their models so equipped in the Japanese market.

===Daytime running lamps===
{{main|Daytime running lamp}}
Daytime conspicuity may be provided by daytime running lamps ([[Daytime Running Lights|DRL]]). These may either be separate lamps, or the function may be provided by other lamps, depending on local regulations. In ECE Regulations, a functionally-dedicated [[Daytime Running Lights|DRL]] must emit [[white]] light with an intensity of at least 400 [[candela]]s on axis and no more than 800 candelas in any direction. Most countries applying ECE Regulations alternatively permit low-beam headlamps to be used as daytime running lamps. [[Hungary]], [[Canada]], [[Sweden]], [[Norway]], [[Slovenia]], [[Austria]], [[Finland]] and [[Denmark]] require hardwired [[Automatic transmission|automatic]] [[Daytime Running Lights|DRL]] systems of varying specification depending on the specific country. DRLs are permitted in many countries where they are not required, but prohibited in other countries not requiring them.

In North America, daytime running lamps may produce up to 7,000 candelas, and can be implemented as high-beam headlamps running at less-than-rated voltage. This has provoked a large number of complaints about [[glare]].

===Rear fog lamps===
(ECE Regulation 38, SAE J1319)
In Europe, vehicles must be equipped with one or two bright red "rear fog lamps" (or "fog taillamps"), which are switched on manually by the driver in conditions of poor visibility to enhance vehicle conspicuity from the rear. The allowable range of intensity for a rear fog lamp is 150 to 300 candelas, which is within the range of a U.S. brake lamp. For this reason, many European vehicles imported to the United States have their rear fog lamps wired as brake lamps, since their European-specification brake lamps may not be sufficiently intense to comply with U.S. regulations, and rear fog lamps are not required equipment in the U.S.

Most jurisdictions permit rear fog lamps to be installed either singly or in pairs. Proponents of twin rear fog lamps say two lamps provide vehicle distance information not available from a single lamp. Proponents of the single rear fog lamp say dual rear fog lamps closely mimic the appearance of illuminated brake lamps (which are mandatorily installed in pairs), reducing the conspicuity of the brake lamps' message when the rear fogs are activated. To provide some safeguard against rear fog lamps' masking of brake lamps, [[ECE Regulations]] require a separation of at least 10 cm between adjacent illuminated edges of brake lamps and rear fog lamps.

==Signalling==

===Turn signals===
Turn signals (properly "directional indicators" or "directional signals", also "indicators," "directionals," "blinkers," or "flashers") are signal [[lamp|light]]s mounted near the left and right front and rear corners, and sometimes on the sides of vehicles, used to indicate to other drivers that the operator intends a lateral change of position (turn or lanechange). [[Electricity|Electric]] turn signal lights were devised as early as [[1907]] ({{US patent|912,831}}), but were not widely offered by major automobile manufacturers until after [[1939]]. Alternative systems of [[cycling hand signals|hand signal]]s were used earlier, and they are still common for [[bicycle]]s (hand signals are also sometimes used when regular vehicle lights are [[malfunction]]ing).

Today, turn signals are required on all vehicles that are driven on public roadways in most countries. They are required to blink on and off, or "flash", at a steady rate of between 60 and 120 blinks per minute. International regulations require that all turn signals activated at the same time flash in phase with one another; North American regulations permit sidemarkers wired for side turn signal functionality to flash in opposite-phase. Worldwide regulations stipulate an [[Sound|audio]] and/or [[visual]] warning be provided to the vehicle operator in the event of a turn signal's failure to light. This warning is usually provided by a much faster- or slower-than-normal flash rate.

In most countries outside North America, cars must be equipped with side-mounted turn signal "repeaters" to make the turn indication visible laterally rather than just to the front and rear of the vehicle. These are permitted, but not required in North America. As an alternative in North America, the front amber sidemarker lights may be wired to flash with the turn signals, but this also is not mandatory. Recently, some automakers have begun incorporating side turn signal devices into the sideview mirror housings, rather than mounting them on the vehicle's fenders. There is some [http://www.umtri.umich.edu/ics-wpd/exec/icswppro.dll?AC=CHANGE_REPORT&XC=/ics-wpd/exec/icswppro.dll&BU=http%3A%2F%2Fwww.umtri.umich.edu%2Flibrary%2Fsimple.html&TN=library&SN=AUTO5723&SE=1597&RN=0&MR=0&TR=0&TX=1000&ES=0&CS=1&XP=&RF=Long%20Record%20%28Date%29&EF=Basic+Record+Form&DF=Short+Record+(Date)&RL=1&EL=1&DL=1&NP=3&ID=&MF=&MQ=&TI=0&DT=&ST=0&IR=0&NR=0&NB=0&SV=0&BG=&FG=&QS=simple&OEX=ISO-8859-1&OEH=ISO-8859-1 evidence] to suggest these mirror-mounted turn signals may be more effective than fender-mounted items.

As with all vehicle lighting and signalling devices, turn signal lights must comply with technical standards that stipulate minimum and maximum permissible intensity levels and minimum horizontal and vertical angles of visibility, to ensure that they are visible at all relevant angles, don't dazzle those who view them, and are suitably conspicuous in conditions ranging from full darkness to full direct sunlight.

Until the early 1960s, most front turn signals worldwide produced white light and most rear signals produced red. Amber front turn signals were voluntarily adopted by the auto industry in the USA for most vehicles beginning in the 1963 model year, though front turn signals were still permitted to emit white light until [[Federal Motor Vehicle Safety Standard 108|FMVSS 108]] took effect for the 1968 model year. Presently, countries outside North America require that all front, side and rear turn signals produce [[Amber (color)|amber]] light. In North America the rear signals may be amber or red. International proponents of amber rear signals say they are more easily discernible as turn signals, and US studies in the early 1990s demonstrated improvements in the speed and accuracy of following drivers' reaction to brake lamps when the turn signals were amber rather than red. US regulators and other proponents of red rear turn signals claim there is no proven lifesaving benefit to amber signals.

====Sequential turn signals====
[[image:SequentialTurnSignal.gif||right|frame|Sequential signal retrofitted to a [[Pontiac Fiero]].]]
[http://www.webelectricproducts.com/products.htm '''Sequential turn signals'''] are a feature on some past-model [[automobile|cars]] whereby multiple lights that produce the rear [[turn signal]] do not all flash on and off in phase. Rather, the horizontally-arrayed lamps are illuminated sequentially: The innermost lamp lights and remains illuminated, the next outermost lamp lights and remains illuminated, followed by the next outermost lamp and so on until the outermost lamp lights briefly, at which point all lamps extinguish together and, after a short pause, the cycle begins again. The visual effect is one of outward motion in the direction of the intended turn or lane change. This implementation has generally been found only on American cars that use combination red rear brake and turn signal lamps.

Sequential turn signals were factory fitted to [[Ford Thunderbird]]s built between 1965 and 1971, inclusive, to [[Mercury Cougar]]s between 1967 and 1973, to [[Shelby]] [[Ford Mustang|Mustang]]s between 1968 and 1970, and to 1969 [[Imperial (automobile)|Imperial]]s (built by [[Chrysler]]). No other production cars were so equipped, initially due to the cost and complexity of the system. [[Federal Motor Vehicle Safety Standard 108]], which regulates [[Automotive lighting|automotive lighting]], was amended in 1970 to require that all turn signal lamps operate in synchronized phase, thus prohibiting sequential turn signals.

Two different systems were employed. The earlier, fitted to the 1965 through 1968 [[Ford Motor Company|Ford]]-built cars, was electro-mechanical, featuring an [[electric motor]] driving, through [[reduction gearing]], a set of three slow-turning [[cam]]s. These cams would actuate switches to turn on the lights in sequence so long as the turn signal switch was set. This system was complicated and prone to failure, and therefore the units are non-functional in many surviving cars.

Later Ford cars and the 1969 [[Chrysler Imperial]] used a transistorized control module with no moving parts; this was much more reliable.

While U.S. Federal and [[Canada|Canadian]] [[motor vehicle]] [[safety]] standards prohibit sequential turn signals on vehicles built after [[1 January]] [[1970]], Federal standards do not apply to vehicles in use, and so extension of this regulation to vehicles in use is left as a matter of choice for each state or province.

===Stop lamps===
Red-colored steady-burning rear lights, brighter than the taillamps, are activated when the driver applies the vehicle's [[brake]]s. These are called '''brake lights''' or '''stop lamps'''. They are required to be fitted in multiples of two, symmetrically at the left and right edges of the rear of every vehicle. Outside North America, the range of acceptable intensity for a brake lamp containing one light source (e.g. bulb) is 60 to 185 [[candela]]. In North America, the acceptable range for a single-bulb brake lamp is 80 to 300 candela.

====Center High Mount Stop Lamp (CHMSL)====
In North America since [[1986]], in [[Australia]] since [[1990]], and in [[Europe]] since [[1998]], a central brake lamp, mounted higher than the vehicle's left and right brake lamps and called a '''Centre High Mount Stop Lamp (CHMSL)''', is also required.

=====Rationale=====
The stop lamps on vehicles are traditionally placed in the same housing as the tail lights and turn signals. The CHMSL, which must burn steadily and is not permitted to flash, provides advance warning to vehicle operators whose view of the braking vehicle's regular stop lamps is blocked by interceding vehicles. The CHMSL also helps to disambiguate brake vs. turn signal messages, particularly in North America, where red rear turn signals identical in appearance to brake lamps are permitted.

=====Placement=====
On passenger cars, the CHMSL may be placed above the backglass, affixed to the vehicle's interior just inside the backglass, or it may be integrated into a [[spoiler (automotive)|spoiler]]. Trucks, vans and commercial vehicles usually have the CHMSL mounted to the trailing edge of the vehicle's roof. The CHMSL must in all cases be laterally centred on the vehicle, and its height is regulated in absolute terms as well as with respect to the mounting height of the vehicle's conventional (left and right) brake lamps.

=====History=====
The 1968–1971 [[Ford Thunderbird]] could be ordered with additional high-mounted brake and turn signal lights. These were fitted in strips on either side of its small rear window. This option was rarely specified. The [[Oldsmobile Toronado]] from [[1971]] had dual high-mounted supplemental brake lights as standard. These innovations were not widely adopted at the time. Auto and lamp manufacturers in [[Germany]] experimented with dual high-mount supplemental brake lamps in the early [[1980]]s, but this effort, too, failed to gain wide popular or regulatory support.

Early studies involving [[taxicab]]s and other fleet vehicles found that a third stop lamp reduced rear-end collisions by about 50%. The lamp's novelty probably played a role, since today the lamp is credited with reducing collisions by about 5%.<ref>{{cite web|url=http://www.nhtsa.dot.gov/cars/rules/regrev/evaluate/808696.html|title=NHTSA Technical Report Number DOT HS 808 696: The Long-Term Effectiveness of Center High Mounted Stop Lamps in Passenger Cars and Light Trucks|author=Kahane, Charles J. and Hertz, Ellen|year=1998|accessdate=2006-04-26}}
</ref> It is possible that today, familiarity with the third stop lamp has reached the extent that drivers may not respond quickly enough if a vehicle without a functioning CHMSL decelerates in front of them, since the familiar cue is absent.

In [[1986]], the [[United States]] [[National Highway Traffic Safety Administration]] and [[Transport Canada]] mandated that all new passenger cars have a CHMSL installed. Because [[Elizabeth Dole]] was [[US Secretary of Transportation|Secretary of Transportation]] at the time, these lights were occasionally referred to as '''Dole lights'''. A CHMSL was required on all new light trucks and vans starting in [[1994]]. CHMSLs are so inexpensive to incorporate into a vehicle that even if the lamps prevent only a few percent of rear end collisions they remain a cost-effective safety feature.

====Emergency Braking Display====
[[Mercedes-Benz]] and [[BMW]] have released vehicles equipped with brake lamps having a standard appearance when the driver brakes normally, and a unique appearance when the driver applies the brakes rapidly and severely, as for example in an emergency. Mercedes' concept is to flash the brake lamps rapidly under heavy deceleration, while BMW is experimenting with brake lamps that "grow larger" under hard braking, through the use of additional lighted compartments not activated under normal braking.

The idea behind such emergency-braking indicator systems is to catch following drivers' attention with special urgency. However, there remains considerable debate over whether the system offers a measurable increase in safety performance. To date, studies of vehicles in service have not shown any significant such improvement. The systems used by BMW vs. Mercedes differ not only in operational mode (flashing vs. growing), but also in such parameters as deceleration threshhold of activation. Data are being collected and analyzed in an effort to determine how such a system might be implemented to maximize a safety benefit, if such a benefit can be realized with visual emergency braking displays. One potentially problematic factor in the implementation of flashing stop lamps in North America is that North American regulations permit flashing brake lamps to be used in lieu of separate rear turn signal and hazard warning lamps (in Europe, all vehicles must have [[amber (color)|amber]] rear turn signals separate from the brake lamps, and flashing-[[red]] was not assigned any meaning until the development of emergency-braking warning systems.)

===Reversing lamps===
To provide illumination to the rear when backing up, and to warn adjacent vehicle operators and pedestrians of a vehicle's rearward motion, each vehicle must be equipped with at least one rear-mounted, rear-facing '''reversing lamp''' (or "backup light"). These are currently required to produce white light by U.S. and international UN/ECE regulations. However, in the past, some countries have permitted amber reversing lamps. A notable example is Australia, which permitted amber reversing lamps until the early 1980s. Vehicle manufacturers, faced with the task of localizing American cars originally equipped with combination red brake/turn signal lamps and white reversing lamps, were able to combine the (mandatorily amber) rear turn signal and (optionally amber) reversing lamp function, and so comply with the regulations without the need to add additional lighting devices to the rear of the vehicles.

===Construction & Technology===

====Light sources====

=====Incandescent Light Bulbs=====
Traditionally, an incandescent tungsten [[light bulb]] has been the light source used in all of the various automotive signalling and marking lamps. Typically, bulbs of 21 to 27 [[watt]], producing 280 to 570 [[Lumen (unit)|lumens]] (22 to 45 [[Candlepower|Mean Spherical Candlepower]]) are used for brake, turn, reversing and rear fog lamps, while bulbs of 4 to 10 W, producing 40 to 130 lm (3 to 10 mscp) are used for tail lamps, parking lamps, sidemarker lamps and side turn signal repeaters. Some recent-model vehicles use small [[Halogen_lamp#The_halogen_lamp|tungsten-halogen]] light bulbs.

=====Light Emitting Diodes (LED)=====
[[LED]]s are being used with increasing frequency in automotive signalling lamps. They operate with much lower power consumption, have longer service lives, are nearly impervious to vibration damage, and permit considerably shallower packaging compared to most bulb-type assemblies. LEDs also offer a significant safety performance benefit when employed in brake lights, for when power is applied they rise to full intensity approximately 200 milliseconds faster than incandescent bulbs. This fast rise time not only improves the attentional conspicuity of the brake lamp, but also provides following drivers with increased time in which to react to the appearance of the brake lamps.

LEDs were first applied to automotive lighting in Center High Mount Brake Lamps (CHMSL), beginning in the early 1990s. Adoption of LEDs for other signal functions on passenger cars has been slow, but is beginning to increase with demand for the technology and related styling updates. The commercial vehicle industry has rapidly adopted LEDs for virtually all signalling and marking functions on trucks and buses, because in addition to the fast rise time and concommitant safety benefit, LEDs' extremely long service life reduces vehicle downtime.

=====Neon tubes=====
[[Neon_lamp|Neon lamp]] tubes have been used as CHMSLs on such vehicles as the late-1990s [[Ford Explorer]], and have been exhibited as features on concept cars from such manufacturers as [[Volvo]]. [[Hella (company)|Hella]] offered an aftermarket Neon CHMSL in the late 1990s. The linear packaging of the Neon light source lends itself to the linear packaging favored for many CHMSL installations, and Neon lights offer the same nearly-instant rise time benefit as LEDs. However, Neon tubes require an expensive and relatively power-hungry [[Ballast (electrical)|ballast]] (power supply unit), and as a result, Neon lights have not found significant popularity as automotive signalling device light sources.

====Variable-Intensity Signal Lamps====
Internationalized [[World Forum for Harmonization of Vehicle Regulations|ECE regulations]] explicitly permit vehicle signal lamps with intensity automatically increased during bright daylight hours when sunlight reduces the effectiveness of the brake lamps, and automatically decreased during hours of darkness when glare could be a concern. Both US and ECE regulations contain provisions for determining the minimum and maximum acceptable intensity for lamps that contain more than a single light source.

== See also ==

*[[Headlamp]]
*[[Hidden headlights]]
*[[Daytime running lamp]]
*[[World Forum for Harmonization of Vehicle Regulations]]
*[[NHTSA]]
*[[Not Invented Here]] syndrome
*[[Federal Motor Vehicle Safety Standard 108]]
*[[Digital vehicle lighting]]
[[Category:Automotive technologies]]

== External links ==
*[http://dastern.torque.net/techdocs/DimDip2.html UK-ILPE Dim-Dip Research & Recommendations]

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== References ==

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