Electronically controlled wastegate valve for a turbo charger

摘要

An electronically controlled wastegate valve is adjusted so that the pressure drop across a throttle in the engine approaches an adaptively generated, desired throttle pressure reserve value. The desired throttle pressure reserve value is based at least in part on a history of the engine load. In the preferred embodiment, the engine speed is used as a surrogate for engine load to determine the desired throttle pressure reserve value. The desired throttle pressure reserve value is preferably pushed downward over time by use of a constant negative gain term in the electronic controller. In this manner, the wastegate control provides sufficient throttle pressure reserve for satisfactory load acceptance when engine load is fluctuating, yet minimizes throttle pressure reserve to improve engine fuel consumption when the engine load is relatively steady.