Patent ID: 6988471

Claim:
An engine valve actuation system, comprising: an engine valve moveable between a first position that blocks a flow of fluid and a second position that allows a flow of fluid; a valve actuation assembly operably connected to move the engine valve between the first position and the second position; a separate fluid actuator configured to selectively modify a timing of the engine valve in moving from the second position to the first position, the separate fluid actuator including a cylinder having a longitudinal direction and a piston cooperating to at least partly define a chamber, the piston having at least one fluid passage and being slidably movable in the cylinder between a first position and a second position; a source of fluid in communication with the separate fluid actuator; and first, second, and third passages longitudinally spaced apart in the cylinder, each of the first, second, and third passages structured and arranged to allow fluid to flow from the source of fluid to the chamber at a time when the piston is moving from the first position to the second position, said piston blocking at least a portion of one of the first, second, and third passages at an intermediate position between the second position and the first position so as to reduce the flow of fluid from the chamber at a time when the piston is moving from the second position toward the first position, the at least one fluid passage of the piston being in communication with at least one of the first, second, and third passages.