Patent ID: 8494748

Claim:
A method for controlling engine torque in a hybrid vehicle, the method comprising: generating torque from an engine with use of a control unit while switching from an electric vehicle mode to a hybrid electric vehicle mode; determining with use of the control unit whether an engine oil pressure reaches a predetermined level; in response to determining that the engine oil pressure is below a predetermined level, limiting an engine demand torque below a level at which system efficiency is maximized; and in response to determining the engine oil pressure has reached the predetermined level, controlling with use of the control unit the engine demand torque to a level at which the system efficiency is maximized, wherein determining whether the engine oil pressure has reached the predetermined level is determined by determining whether an intake cam is activated, and wherein determining whether the intake cam is activated includes: measuring the engine oil pressure at the intake cam; measuring the time required until an effective oil pressure is achieved in the engine so that the intake cam becomes movable; inputting the measured time to an engine control unit in a form of mapping data; and determining, at the engine control unit, that the intake cam has been activated when the measured time has elapsed after the engine is operated.