IMA System: Notes

The IMA (integrated motor assist) system is a high efficiency hybrid system that consists of a gasoline-powered engine and an electric motor.

The IMA system uses the engine as its main source and the motor as a supplemental source. By using the two units, overall weight is lower than a powertrain that uses an electric motor as its only source of power.

High voltage DC circuits such as the battery module, junction board, PCU (power control unit), etc. are stored in the IPU (intelligent power unit), which is located at the rear of the vehicle for efficient packaging and for safety.

The inline, 3-cylinder, SOHC, 12-valve engine displaces 0.995 liter. It is a sequential multipoint fuel-injected engine specially developed for the IMA system.

The motor is a DC brushless type located between the engine and the transmission. In addition to assisting the engine, it starts the engine and acts as a generator to recharge the battery.

The MCM (motor control module) controls the motor through the MPI (motor power inverter) module and the voltage control unit. The MCM determines the amount of assist and regenerative power needed by communicating with the BCM (battery condition monitor) module to prevent excessive battery drain and to prevent battery overcharging.

A 144 V Ni-MH (nickel-metal hydride) battery powers the motor. Power to the vehicle's conventional 12 V circuits is supplied by the battery module with voltage reduction done through the DC-DC converter.