During acceleration, power to the wheels is supplied by the IMA system's gasoline engine, assisted by the IMA electric motor. Electric power for the motor is stored in the Integrated Power Unit's (IPU) nickel-metal hydride battery pack.
Power for steady-state cruising is supplied solely by the IMA system's gasoline engine.
During deceleration and braking, the IMA-system motor acts as a generator in order to recharge the IPU battery pack.
When the IMA system is idling, or when the idle-stop feature is engaged, the IPU battery pack is not supplying power or being recharged.