Modes of Operation

Creep 

The hybrid electric system delivers torque to the wheels to mimic the creep mode normally found on vehicles equipped with an automatic transmission. The Inverter System Controller (ISC), also known as the SOBDMC, commands a predetermined amount of torque to be delivered to the output shafts of the electronically controlled transmission. This torque is delivered from the combination of the internal combustion engine, the traction motor, or the generator motor. The maximum creep speed in forward or reverse direction is about 6 km/h (4 mph). The creep speed may vary slightly if ambient temperature, altitude, relative humidity, engine temperature, or weight of the vehicle changes.

Electric 

The system operates in this mode when the vehicle is propelled by the electrical power stored in the high voltage battery. The torque is supplied to the output shafts by the electric motor. This is the preferred mode whenever the desired torque is low and can be produced more efficiently by the electrical system than the engine.

• Drive - The electric motor drives transmission providing torque to wheels meeting driver demand.
• Driven -The transmission is driven by inertia of vehicle and provides regenerative energy to electric motor meeting all or a portion of the braking demand.

Engine Cranking 

The generator motor provides the engine cranking function to start or restart the internal combustion engine. When the PCM requests the engine cranking mode, the generator motor rapidly accelerates the engine speed up to about 950 RPM in about 0.3 seconds. When the engine speed reaches a calibrated speed the PCM commands the delivery of fuel and spark at the appropriate time.

Hybrid 

The system operates in this mode when the engine is running and powering the electric motor which produces the electricity. The electricity produced by the electric motor charges the high voltage battery. In this mode the electric motor can operate as a motor or as a generator to make up the difference between engine torque and desired torque at the wheels. This mode is preferred whenever the electric battery needs to be charged or at moderate loads at low speeds.

• Drive - The engine drives the transmission providing torque to the wheels meeting driver demand. Requested torque above this demand is used to charge high voltage battery through the electric motor. Electric motor can also assist engine.
• Driven - The transmission is driven by inertia of vehicle and provides regenerative energy to electric motor meeting all or a portion of the braking demand. Engine can provide compression braking.

Series 

The system operates in this mode when the engine is running and the vehicle is not moving. This is the preferred mode whenever the high voltage traction battery is charging, passenger compartment temperature control, high voltage traction battery temperature control or catalyst warm up is necessary.

Positive Split 

The system operates in this mode when the engine is running and powering the generator motor which produces the electricity. The power from the engine is split between the path through the generator motor and the path to the output shafts of the vehicle. The electricity produced by the generator motor charges the high voltage traction battery or powers the traction motor. In this mode the traction motor can operate as a motor or as a generator to make up the difference between engine torque and desired torque at the wheels. This mode is preferred whenever the traction battery needs to be charged or at moderate loads at low speeds.

Negative Split 

The system operates in this mode when the engine is running but the generator motor is reducing the engine speed. This mode occurs if the engine is running, the vehicle speed is high and the high voltage traction battery is charged.