Patent ID: 8020652
Filing Date: 2011-09-20
Classification: B60K,B60W,Y02T,Y10S

Abstract:
1. A method for controlling a start event of an engine in a hybrid electric vehicle powertrain comprising an internal combustion engine forming a first power source, an electric generator, a battery and an electric motor forming a second power source, gearing defining power flow paths from the first and second power sources to vehicle traction wheels, the generator and the engine being mechanically connected to separate elements of the gearing whereby the generator, acting as a motor, delivers engine cranking power to the engine when engine torque is detected during an engine start event, the method comprising the steps of: controlling a target generator power in a closed-loop fashion using actual generator power as a feedback variable throughout an engine start event whereby generator torque assists engine torque at engine speeds less than a stable engine idle speed when engine combustion is unstable.