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Integrated Motor Assist (IMA): Difference between revisions
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===Civic Hybrid=== | ===Civic Hybrid=== | ||
[[Image:2006_Civic_Hybrid.jpg|frame|2006 Honda Civic Hybrid]] | [[Image:2006_Civic_Hybrid.jpg|frame|2006 Honda Civic Hybrid]] | ||
In its first generation, IMA technology could not power the car on electricity alone, and could only use the motor to assist or start the engine. Like the Insight, the 2003-2005 Civic Hybrid was considered a mild hybrid. By 2006, however, it moved into full hybrid territory. Its electric motor is now able to propel the car from a stop to speeds up to 35 mph; while the Civic Hybrid cannot start from a stoplight under electric power alone, it can activate the electric motor while the vehicle is coasting without turning the ICE on, providing the sole means of propulsion. | In its first generation, IMA technology could not power the car on electricity alone, and could only use the motor to assist or start the engine. Like the Insight, the 2003-2005 Civic Hybrid was considered a mild hybrid. By 2006, however, it moved into full hybrid territory. Its electric motor is now able to propel the car from a stop to speeds up to 35 mph; while the Civic Hybrid cannot start from a stoplight under electric power alone, it can activate the electric motor while the vehicle is coasting without turning the ICE on, providing the sole means of propulsion. | ||
===Accord Hybrid=== | ===Accord Hybrid=== | ||
Revision as of 18:09, 9 July 2006
Integrated Motor Assist (commonly abbreviated as IMA) is Honda's hybrid car technology, introduced in 1999 on the Insight. It uses both a gasoline engine and a thin, compact permanent magnet electric motor/generator mounted between the engine and transmission to act as a starter motor, engine balancer, and assist traction motor. The internal combustion engine (ICE) provides all the power needed for most driving situations. When additional power is needed, such as under initial acceleration from a stop, during passing or when climbing grades, the integrated electric motor/generator performs in ways similar to a supercharger, seamlessly kicking in to supply additional power. The motor/generator also functions as a high-speed starter and as a generator for battery charging during regenerative braking. A nickel-metal-hydride (NiMH) battery pack is used in all Honda hybrids; it features stable output characteristics regardless of the state-of-charge status and is also extremely durable, designed to last 10 years under normal driving conditions.
The theory behind IMA is to use Regenerative Braking to recapture some of the energy lost through deceleration, and reuse that energy later on to help accelerate the vehicle. This has two effects: it increases the rate of acceleration, and it reduces the work required of the gasoline engine. The acceleration boost is important, as it allows the engine to be scaled down to a smaller but more fuel-efficient variant without rendering the vehicle overly slow or weak. This smaller engine is the primary reason cars equipped with IMA get better highway mileage than their more conventional counterparts.
Additionally, vehicles equipped with IMA can shut off their engine when the vehicle stops and use the electric motor to rapidly spin it back up when the driver releases the brake pedal. They also have a conventional starter as a backup, making it the only production hybrid system which can operate with its high voltage electric system disabled, using only its ICE like a traditional vehicle. However, since the IMA also acts as the vehicle's alternator, eventually the 12 V accessory battery would require an external charge.
Honda Integrated Motor Assist (IMA) Applications
Vehicles Using IMA:
- Honda Insight (1999-2006)
- Honda Civic Hybrid (2003-)
- Honda Accord Hybrid (2005-)
Insight
The Insight is most commonly referred to as a Mild Hybrid vehicle. In mild hybrids, the gas engine provides the main propulsion, and the electric motor provides assist whenever extra power is needed. In this arrangement, the electric motor cannot operate independently of the gas engine. The electric motor can generate electricity for the battery or consume electricity from the battery, but not both at the same time. In contrast, a Full Hybrid integrates the electric motor, gas engine and battery, so that the electric motor can operate on its own when certain conditions are met. For some hybrids, it does this under low speed; once the vehicle reaches higher speeds, the gasoline engine starts up and takes over. Under hard acceleration, both the gas engine and the electric motor can work together to provide the needed power. Unlike mild hybrids, full hybrids are able to generate and consume electricity at the same time.
Civic Hybrid
In its first generation, IMA technology could not power the car on electricity alone, and could only use the motor to assist or start the engine. Like the Insight, the 2003-2005 Civic Hybrid was considered a mild hybrid. By 2006, however, it moved into full hybrid territory. Its electric motor is now able to propel the car from a stop to speeds up to 35 mph; while the Civic Hybrid cannot start from a stoplight under electric power alone, it can activate the electric motor while the vehicle is coasting without turning the ICE on, providing the sole means of propulsion.
Accord Hybrid
The all-new 2005 Honda Accord Hybrid was the first V6-powered hybrid vehicle to market, adding more power to Honda's hybrid lineup while still retaining gas mileage and emissions levels more in line with the Civic Hybrid. In fact, the Accord Hybrid combines its V6 and electric motor to generate a total of 253 horsepower - 9 more than the standard gasoline-only V6 engine.
The Accord Hybrid utilizies the third generation of Honda's advanced IMA full hybrid system and incorporates a new Variable Cylinder Management (VCM) cylinder deactivation technology. When cruising at steady speeds where less engine power is required, the VCM system deactivates the V-6 engine's rear bank of cylinders, closing both the intake and exhaust valves for reduced fuel consumption. Under light acceleration from a cruising state, the IMA motor can provide power assistance to the engine in three-cylinder mode. When coming to a stop, the IMA system shuts off the vehicle's engine at speeds below 10mph to reduce fuel consumption and exhaust emissions. At the moment the driver releases the brake pedal, the IMA motor instantaneously restarts the gasoline engine.
