Patent ID: 6739293
Filing Date: 2004-05-25
Classification: F01L,F02B,Y02T,Y10T

Abstract:
Apparatus adapted for operating an engine valve, comprising:a hydraulic actuator operable to selectively move the engine valve toward an engine valve open position by the pressure of a fluid acting on the hydraulic actuator; a proportional valve having a valve member moveable between a first position at which the proportional valve is adapted to couple a source of fluid under a first pressure to the hydraulic actuator, a second position at which the proportional valve is adapted to couple the hydraulic actuator to a reservoir of fluid under a second pressure, the second pressure being less than the first pressure, and a third position at which the proportional valve blocks fluid communication between the hydraulic actuator and the source of fluid under the first pressure, and also blocks fluid communication between the hydraulic actuator and the reservoir of fluid under the second pressure; electrically controlled valving hydraulically controlling the position of the valve member; and, an engine valve return operable to return the engine valve to a closed position.