Method of increasing torque and/or reducing emissions by varying the timing of intake and/or exhaust valves

Abstract

A method of improving the operating characteristics of an internal combustion engine equipped with electronic throttle control employs variable cam timing to vary the phasing of the intake valves and/or exhaust valves so as to achieve lower feed gas emissions and improved fuel economy while delivering as closely as possible the desired torque. The method can be implemented using a fuel-lead strategy or an air-lead strategy. Whenever a change is requested in the amount of torque, the method responds by adjusting the amount of fuel flow, the spark timing, the position of the throttle and/or the positions of the intake valves and/or the exhaust valves so as to deliver the desired torque. The method adjusts those operating parameters in a way that improves the ability of the engine to deliver the desired torque, produce less feed gas emissions, idle more stably, and consume less fuel.