Valve operation control system of internal combustion engine.

摘要

A valve operation control system for an internal combustion engine having an engine valve (5) supported in an engine body (1) for opening and closing. A phase control means (17) is interposed between a crankshaft and the valve operating cam shaft to control the rotating phase of the crankshaft relative tot the valve operating cam shaft. A valve drive means (16) is interposed between the valve operating cam and the engine valve to transmit the valve opening force by the valve operating cam to the engine valve. The valve drive means (16) includes a resilient valve opening means for generating resilient force in the valve opening direction and a holding means (9) for holding the engine valve in a closed position while springs accumulate the valve opening force. The holding means (9) is selectively operable to switch between a valve holding state and a valve releasing state to control the valve opening timing of the engine valve in response to operating conditions of said engine.