Valve operating device for internal combustion engine

Claim 1

A valve operating mechanism for intake or exhaust valves of an internal combustion engine having a low-speed cam formed on a camshaft and suited for an operation mode of the intake or exhaust valves during low-speed operation of the engine, a high-speed cam formed on said camshaft and suited for an operation mode of the intake or exhaust valves during high-speed operation of the engine, a cam follower held in slidable contact with said low-speed cam, a cam follower held in slidable contact with said high-speed cam, a selective coupling mechanism disposed between said cam followers fo selectively connecting and disconnecting the cam followers in order to open and close the intake or exhaust valves dependent on the operating speed of the engine, an improvement comprising, a low-speed lubricating oil passage for supplying lubricating oil to sliding surfaces of the low-speed cam and the associated cam follower, a high-speed lubricating oil passage for supplying lubricating oil to sliding surfaces of the high-speed cam and the associate cam follower, said low-speed lubricating oil passage and said high-speed lubricating oil passage being separate of each other, an oil supply source, and a control valve connected between said oil supply source and said low-speed lubricating oil passage and said high-speed lubricating oil passage, said control valve being selectively operable for communicating said high-speed lubricating oil passage and said oil pressure supply source throughout a full operating range of the engine while restricting the rate of flow of oil during low-speed operation of the engine and for communicating said low-speed lubricating oil passage and said oil pressure supply source at least during low-speed operation of the engine.