Valve operating device for internal combustion engine

Abstract From the Canadian patent

A valve operating device for an internal combustion engine that includes a valve piston having one end facing into a damper chamber and the other end operatively coupled to an intake or exhaust valve which is spring-biased in a closing direction. A cam piston has one end operatively coupled to a cam drivable by a crankshaft and the other end disposed in a working oil chamber. A restriction mechanism uniformly restricts oil flow during final valve closing operation of the intake or exhaust valve until the valve is fully closed. The working oil chamber and damper chamber are held in communication with each other through the restriction mechanism. A bypass passage interconnects the damper …