Hydraulic valve system for controlling flow of gas into or out of a variable volume chamber of an internal combustion engine or compressor

Abstract

The present invention relates to a valve system for controlling flow of gas into or out of a variable volume chamber ( ) of an internal combustion engine or a compressor. The valve system comprises a gas flow control valve ( ) which opens to permit flow of gas into or out of the variable volume chamber ( ); a hydraulic actuator ( ) connected to the gas flow control valve ( ); a pump ( ) for pressurizing hydraulic fluid; a reservoir of hydraulic fluid ( ); and a control system ( ) which controls opening and closing of the gas control valve ( ) by controlling flow of hydraulic fluid to the hydraulic actuator ( ) from the pump ( ) and flow of hydraulic fluid from hydraulic actuator ( ) to the reservoir ( ). The control system comprises an electrically controlled flow direction control valve ( ) which controls direction of flow of hydraulic fluid to the actuator ( ) to control whether the hydraulic actuator ( ) opens or closes the gas flow control valve ( ); and an electrically controlled switching valve ( ) which controls whether or not any hydraulic fluid flows to the hydraulic actuator ( ) and thereby controls the time of opening and closing of the gas flow control valve(s). The pump ( ) is an electrically controlled variable flow rate pump ( ) which controls the rate of opening or closing of the gas flow control valve ( ) by controlling the rate of flow of hydraulic fluid to the hydraulic actuator. Operation of the pump ( ), flow direction control valve ( ) and the switching valve ( ) is controlling by an electronic controller ( ).