Abstract: An improved method of estimating the oil temperature of an internal combustion engine models the net heat flow through the oil during operation of the engine based on known engine operating parameters and integrates the net heat flow to update the oil temperature estimate. The net heat flow components include heat added to the oil due to fuel combustion and heat rejected from the oil to the engine coolant and atmospheric air, and are based on heat transfer coefficients that are adjusted to take into account variations in engine speed, vehicle speed and cooling fan operation.

Abstract: An improved method of estimating the oil temperature of an internal combustion engine models the net heat flow through the oil during operation of the engine based on known engine operating parameters and integrates the net heat flow to update the oil temperature estimate. The net heat flow components include heat added to the oil due to fuel combustion and heat rejected from the oil to the engine coolant and atmospheric air, and are based on heat transfer coefficients that are adjusted to take into account variations in engine speed, vehicle speed and cooling fan operation.

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.