Engine Start-Stop

As the driver depresses the accelerator pedal further, demanding increased vehicle acceleration, drive motor 1 is used to start the engine while the Hybrid Low 1-2 Clutch remains locked and motor 2 simultaneously provides output power to the wheels. During the engine start event motor 1 also provides active damping to reduce torque disturbances from engine cylinder firing pulses, and motor 2 is used to damp driveline disturbances. During this event the inverter draws DC power from the battery and converts it to AC power for both motors. They HPCM controls each motor's speed and power independently. The HPCM determines when to stop the engine and when to restart based on vehicle operating conditions and optimal hybrid battery power and fuel consumption. The engine is stopped at idle and during deceleration maneuvers to improve fuel economy.