Patent ID: 6957634

Claim:
An engine valve actuator for an internal combustion engine, comprising: a housing having an opening and a first fluid passageway leading to the opening; an adjustment member disposed in the housing and including a protrusion extending into the opening of the housing; a piston disposed in the opening of the housing and having a bore adapted to receive the protrusion, a chamber, and a second fluid passageway connecting the bore with the chamber, the piston adapted to move in a first direction relative to the housing in response to an introduction of pressurized fluid into the first fluid passageway, the piston moving in the first direction until the protrusion substantially withdraws from the bore; and a push rod operatively engaged with the piston such that movement of the piston in the first direction causes a corresponding movement of the push rod to thereby engage and open the engine valve; and a piston return spring acting on the piston to move the piston into engagement with the protrusion, wherein the piston return spring and the push rod are disposed in the chamber of the piston.