HDABOB's Tech Notes:

Do you ever wonder how Hybrid IMA (Integrated Motor Assist) vehicles work?

Let me explain it to you...

The components of the Hybrid IMA system consist of:


Electric Motor

PCU (Powertrain Computer Unit)


Battery Pack


HYBRID Cars are a type of propulsion that is slightly different from the average car. A Hybrid car has an internal combustion engine and a transmission, just like a regular car. But, between the engine and the transmission, there is an electric motor attached to the engine, driven by a battery pack under or in the rear of the car.

The benefit of a hybrid vehicle, is that the engine does not have to work as hard to propel the vehicle up to speed. Thereby increasing the average mileage that a given vehicle produces.

The PCM controls the output of the engine and electric motor in 5 steps.

1- When maximum acceleration is required, at wide open throttle, the engine is at maximum torque. The electric motor is also at maximum torque driving the vehicle.

2- When the throttle is not at wide open throttle (cruise), the engine alone drives the vehicle without assist from the electric motor.

3- When little torque is required, the engine is providing power as well as power from the electric motor.

4- During deceleration, the PCM stops fuel injection in all cylinders, and the electric motor acts like a generator to charge the battery.

5- When the vehicle comes to a stop, the engine dies. As soon as the brake pedal is released the engine is restarted by the IMA motor. 


Manufacturers all have different methods of producing the same thing.

The engines are usually smaller than comparable models of the same brand because a larger engine uses more gasoline. All hybrids are controlled by PCU. The computer controls the amount of power produced by the engine and the electric motor. The power is then routed to the transmission. A gauge on the dash shows the amount of battery power remaining and the amount of boost available to drive the car.

On Honda Cars, the electric motor between the engine and transmission is a narrow, multiple pole 144 volt AC linear motor. The rotor of the motor is attached to the engine, acting like a flywheel. The stator is built into the case of the narrow electric motor.  When the engine runs, up to 144 Volts AC electrical power is generated. This voltage is used to charge the battery pack. When additional power is needed, the battery supplies 144 volts DC power to the electric motor augmenting the power of the engine to accelerate the vehicle.

 Additional power for the battery is generated by the braking action of the vehicle.

The transmission used in Hybrid vehicles is sometimes called a CVT transmission. see transmission.htm 


...and that's the way the Hybrid vehicle system work!!

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HDABOB's Mobile Service 10/07/2008