Valve operating system for internal combustion engine.

摘要

A valve-operating system for an internal combustion engine, which system includes a valve-driving piston (13) slidably received in a cylinder body(12) and operatively connected at one end of the piston to an engine valve(5) spring-biased in a closing direction. A check valve (41) and an orifice (45)are interposed between a hydraulic pressure generating means for generating an oil pressure for causing opening of the engine valveand a damper chamber (39) defined between the cylinder body and the valve-driving piston. The check valve permits only the flow of working oil from the hydraulic pressure generating means to the damper chamber. The orifice restricts the return of working oil from the damper chamber to the hydraulic pressure generating means. The orifice is made sufficiently short relative to its width to reduce the influence due to viscosity variations of the working oil to an extremely small level.