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| [[Image:FordEssexV6.jpg|thumb|right|The [[Ford Essex V6 engine]]]]
| | #REDIRECT [[V6 engine]] |
| {{Redirect2|V6|V-6}}
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| A '''V6 engine''' is a [[V engine]] with six [[cylinder (engine)|cylinder]]s. It is the second most common engine configuration in modern cars after the [[straight-4]]; it shares with that engine a compactness very suited to the popular [[front-wheel drive]] layout, and is becoming more popular as car weights increase.
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| The first V6 was introduced by [[Lancia]] in [[1950]] with the [[Lancia Aurelia]], other manufacturers took note and soon other V6 engines were in use. The design really took off after the 1962 introduction of the [[Buick Special]]. Though the model was not a spectacular success, it was the first mass-produced V6 engine.
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| ==Vee angles==
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| A V6 is not a perfectly balanced engine and benefits from some [[balance shaft|counterbalancing]] and harmonic damping. The optimal angle to minimize vibrations in the V6 is 60°, and this is commonly used. The most common 60° V6s were built by Ford European subsidiaries : [[Ford Essex V6 engine (UK)|Essex V6]], [[Ford Cologne V6 engine|Cologne V6]] and the more recent [[Ford Duratec|Duratec V6]]. The [[Alfa-Romeo]] V6 is also common.
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| 90° V6 engines have also been produced, often to take advantage of production-line machinery set up for V8 engines (for which 90° is optimal). This design was first used by [[Buick]] when it introduced its [[Buick V6 engine#198|198 in³ ''Fireball V6'']] as the standard engine in the [[1962]] [[Buick Special|Special]]. Other examples include the [[Maserati]] V6 used in the [[Citroën SM]], the [[PRV engine|PRV]] V6, [[Chevrolet]]'s [[GM Vortec engine#4300|4.3 L ''Vortec 4300'']] and [[Chrysler Corporation|Chrysler]]'s [[Chrysler LA engine#238|3.9 L ''Magnum V6'']] and [[Chrysler PowerTech engine#3.7|3.7 L ''PowerTech V6'']].
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| Narrow angle V6 engines are very compact but suffer from vibration. Lancia's [[1924]] engine was such a design; Lancia produced similar engines until the [[1970s]]. More recently, [[Volkswagen]] have used such a design, known as the [[VR6 engine]]. In this engine, both banks share the same cylinder head and are extremely close together.
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| Other notable V6 bank angles:
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| * The 10.6° and 15° [[Volkswagen]] VR6, a V6 with such a narrow angle it shares many characteristics with the [[straight-6]], such as its firing order and use of a single cylinder head.
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| * The 54° [[GM 54-Degree V6 engine|GM/Opel V6]], designed to be narrower than normal for use in small [[front-wheel drive]] cars.
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| * The 65° [[Ferrari Dino]] V6. The engine was originally fed by [[carburetor]]s. A 60° angle was limiting the size of the carburetors, while a 65° angle allowed to mount larger carburetors to the expense of a slight increase of vibrations.
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| ==Odd and even firing==
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| Many V6 engines have been based on [[V8 engine]] designs. One characteristic of these engines is a notorious ''odd-firing'' behavior.
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| Purpose-built V6 engines use one crankpin per cylinder for a smooth ignition 120° ignition pattern. In contrast, most V8 engines share a common crankpin between opposite cylinders in each bank. That is, the [[crankshaft]] has just four pins for eight cylinders, and a cylinder fires every 90° for smooth operation.
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| V6 engines that are converted from V8 engines often have three shared crankpins arranged at 120° from each other, similar to an [[Straight-3|inline 3-cylinder]] with two pistons per crankpin. If the cylinder banks are arranged at 90° (as they commonly are in V8-derived V6s), this leads to a firing pattern with groups of two cylinders separated by 90° of rotation, and groups separated by 150° of rotation.
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| An example is the [[Buick V6 engine#231|Buick 231 odd-fire]], which has a [[firing order]] 1-6-5-4-3-2. As the crankshaft is rotated through the 720° required for all cylinders to fire, the following events occur on 30° boundaries:
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| Nissan use the firing order 1-2-3-4-5-6 in some of the V6 engines they make
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| <div align=center>
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| {| width=90%
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| |- align=left
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| |width=12%|'''Angle'''
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| |colspan=9 width=11%|0°
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| |colspan=9 width=11%|90°
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| |colspan=9 width=11%|180°
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| |colspan=9 width=11%|270°
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| |colspan=9 width=11%|360°
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| |colspan=9 width=11%|450°
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| |colspan=9 width=11%|540°
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| |colspan=9 width=11%|630°
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| |- align=left
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| |'''Odd firing'''
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| |colspan=9 width=11%|1
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| |colspan=15 width=18%|6
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| |colspan=9 width=11%|5
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| |colspan=15 width=18%|4
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| |colspan=9 width=11%|3
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| |colspan=15 width=18%|2
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| |-
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| |'''Even firing'''
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| |colspan=12 width=14%|1
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| |colspan=12 width=14%|6
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| |colspan=12 width=14%|5
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| |colspan=12 width=14%|4
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| |colspan=12 width=14%|3
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| |colspan=12 width=14%|2
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| |}
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| </div>
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| In [[1977]], [[General Motors Corporation|General Motors]] introduced a unique "split-pin crankshaft" in the [[GM 3800 engine]]. Using a crankpin that is 'split' and offset by 30° of rotation results in smooth, even firing. Such a 'split' crankpin is weaker than a straight one, but modern materials and manufacturing produce a crankshaft that is strong enough. In [[1986]] the similarly-designed 90° [[PRV engine]] adopted the same 30° crankshaft offset design to even out its firing.
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| ==Racing use==
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| The V6 engine was introduced into racing by the Ferrari Dino V6. [[Alfredino Ferrari|Alfredo Ferrari]] (nicknamed Dino), the only legitimate son of [[Enzo Ferrari]], suggested to him the development of a 1.5 L [[DOHC]] V6 engine for F2 at the end of [[1955]]. Soon afterwards, Alfredo fell ill, suffering from [[muscular dystrophy]]. While in hospital, he discussed technical details with the engineer [[Vittorio Jano]]. Dino would never see the engine; he died on [[1956-06-30]] at the age of 24.
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| The Dino V6 underwent several evolutions, and—with an increased [[engine displacement]]—competed in the 2.5 L [[Formula One]].
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| Until the advent of wing cars, a wide 120° bank angle was appealing for racing engine designers as it permits a low [[center of gravity]]. It was even considered superior to the [[flat-6]] in that it leaves more space under the engine for exhaust pipes; thus the crankshaft can be placed lower in the car. A further evolution of the [[Ferrari]] Dino built for new Formula One 1.5 L regulations engines had this configuration.
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| This engine saw a new evolution in [[1966]] when it was adapted to road use and produced by a Ferrari-Fiat joint-venture for the Fiat Dino and Dino 206 GT (this car was made by Ferrari but sold under the brand Dino). This new version was redesigned by [[Aurelio Lampredi]] initially as a 65° 2.0 L V6 with an aluminum block but was replaced in [[1969]] by a 2.4 L cast-iron block version (the Dino car was renamed the 246GT).
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| The Fiat Dino and Dino 246GT were phased out in 1974, but 500 engines among the last built were delivered to [[Lancia]], who was like Ferrari already under the control of [[Fiat]]. Lancia used them for the [[Lancia Stratos]] which would became the most successful car in [[Rally racing]] history.
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| Another influential V6 design was the [[Renault]]-[[Gordini]] CH1 V6, designed by [[François Castaing]] and [[Jean-Pierre Boudy]], and introduced in [[1973]] in the [[Alpine (car)|Alpine]]-Renault A440. The CH1 was a 90° [[cast iron]] block V6, similar to the mass produced PRV engine in those two respects but otherwise dissimilar. It has been suggested that marketing purposes made the Renault-Gordini V6 adopt those characteristics of the PRV in the hope of associating the two in the public's mind.
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| Despite such considerations, this engine won the European 2 L prototype championship in [[1974]] and several European Formula 2 titles. This engine was further developed in a tubocharged 2 L version that competed in Sports car and finally won the [[24 Hours of Le Mans]] in 1978 with a Renault-Alpine A 442 chassis.
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| The capacity of this engine was reduced to 1.5 L to power the Formula One Renault RS01. Despite frequent breakdowns that resulted in the nickname of the 'Little Yellow Teapot', the 1.5 L finally saw good results in 1979.
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| Ferrari followed Renault in the turbo revolution by introducing a turbocharged derivative of the Dino design (a 1.5 L 120° V6) with the Ferrari 126.
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| Both Renault and Ferrari failed in their attempt to win the Drivers's Championship with V6 Turbo engine. The first turbocharged engine to win the championship was the [[Straight-4]] [[BMW]].
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| They were followed by a new generation of Formula One engines the most successful of these being the TAG V6 (designed by [[Porsche]]) and the [[Honda]] V6. This new generation of engines were characterized by odd V angles (around 80°). The choice of these angles was mainly driven by aerodynamic consideration. Despite their unbalanced designs these engines were both quickly reliable and competitive; this is generally viewed as a consequence of the quick progress of CAD techniques in that era.
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| ==External links==
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| * [http://home.off-road.com/~merls_garage/oddfire.html Understanding the odd-fire V6]
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| {{Piston engine configurations}}
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| [[Category:Piston engine configurations|V-06]]
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| [[ja:V型6気筒]]
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