Hydraulic actuator for gas exchange valve of internal combustion engine, has hydraulic jack with chamber whose hydraulic liquid is evacuated by return conduit with less static pressure, where chamber is kept under low pressure

摘要

The actuator has a hydraulic jack (3) for actuating a gas exchange valve (1). The jack has a chamber (7) and a control valve (MV1) for controlling flow in a high pressure supply conduit. The hydraulic liquid of the chamber is evacuated by a return conduit without pressure or with less static pressure. The conduits are connected hydraulically with the jack and the chamber is kept under low pressure. An independent claim is also included for a method of controlling a hydraulic actuator particularly a gas exchange valve.