Patent ID: 6886509

Claim:
An actuator for actuating the gas exchange valves of an internal combustion engine, whereby the gas exchange valves are actuated by hydraulic fluid conveyed by a feed pump in an open circuit equipped with a storage tank, whereby the opening or closing of the gas exchange valves is produced by actuating forces emanating from the hydraulic fluid flowing through the circuit and acting at different levels on the respective gas exchange valve to be actuated, downstream from the respective gas exchange valve, the flow cross section of the circuit is constricted or even closed with respect to all areas upstream from this gas exchange valve, at least during the duration of a hydraulically actuated opening or closing of the gas exchange valve, the hydraulic actuating force on the gas exchange valve is counteracted by a force, in particular a spring force, characterized in that the feed pump ( 6 ) is designed for a delivery operation which operates intermittently and works at a clock frequency above that of the opening and closing frequency of the gas exchange valves.