DYNAMIC VALVE DEVICE FOR INTERNAL-COMBUSTION ENGINE

摘要

PURPOSE:To reduce a friction loss at a cam shaft by a method wherein a spring load of a valve spring is made variable in response to the operating condition of the internal-combustion engine. CONSTITUTION:A spring for use in biasing a valve 3 in its closing direction is composed of an inner spring 7 and an outer spring 8. At least one of the seats 6 for the springs 7 and 8 is formed with a piston 13 and the seat 6 can be moved in an extending or retracting direction under a hydraulic pressure applied in the hydraulic chamber 16. In a low speed range, the spring load is decreased lower than that found in a high speed range, thereby a lubricating condition at the cam shaft can be improved and a friction loss of the engine can be decreased.