Patent ID: 7576501
Filing Date: 2009-08-18
Classification: B60K,B60W,Y02T

Abstract:
1. A method for enhancing reverse driving torque in a hybrid electric vehicle powertrain having an engine, an electric motor, an electric generator, a battery; and gearing forming separate power flow paths during forward drive to vehicle traction wheels from the engine and the motor, and from the electric motor and the generator, acting as a motor, during reverse drive, the electric generator and the battery being electrically coupled, and a controller for coordinating power delivery through the separate power flow paths during forward drive and during reverse drive, the motor operating in one direction during forward vehicle drive and in a direction opposite to the one direction during reverse vehicle drive, the method comprising the steps of: calculating a desired traction wheel torque in response to a driver demand for torque during reverse drive; determining a need to complement reverse driving torque of the motor; determining whether the battery has capacity to supply electric energy to the motor and to the generator acting as a motor to meet a driver demand for reverse driving torque; determining whether the engine should be on or off; determining an engine torque adder to traction wheel torque when the engine is not fueled; and adding the engine torque adder to reverse-driving torque whereby total reverse driving vehicle performance is enhanced.