US Patent 7992389 Method and apparatus for actively turbocharging an engine

A system and method for monitoring at least one operating parameter indicative of an operating condition of an engine and controlling a turbocharger assist device to maintain desired operating conditions of the engine equipped with a turbocharger. In one embodiment, a controller is provided to control operation of a turbocharger assist device in an engine for generating electric power when an excess of energy exists in the exhaust of the engine to subtract work from a turbocharger drive shaft.