Patent ID: 6657315
Filing Date: 2003-12-02
Classification: B60K,B60W,F02D,Y02T

Abstract:
A method of operating a hybrid electric vehicle having a drive train, the drive train having an internal combustion engine and electric machine coupled thereto, the internal combustion further being coupled to a catalytic converter, the method comprising:detecting a temperature of the internal combustion engine; detecting a temperature of the catalytic converter; detecting an engine cold-start condition if the temperature of the internal combustion engine is less than a predetermined engine temperature threshold; determining a negative torque value based one or both of the temperature of the internal combustion engine and the temperature of the catalytic converter; controlling the electric machine according to the negative torque value to apply a negative torque to the internal combustion engine, thereby increasing a power output of the internal combustion engine and the temperature of the catalytic converter; while applying the negative torque, operating the internal combustion engine using a lean air-fuel ratio and retarded spark timing; and once the temperature of the catalytic converter exceeds a predetermined catalytic converter temperature threshold, controlling the electric machine to terminate the negative torque applied to the internal combustion engine, and controlling the internal combustion engine to terminate the retarded spark operation thereof, wherein the predetermined catalytic converter temperature threshold corresponds to operation of the catalytic converter at or above a predetermined calibratable efficiency percentage of the catalytic converter.