VARIABLE VALVE DRIVE FOR AN INTERNAL COMBUSTION ENGINE

摘要

The invention relates to a variable valve drive with a device for an operating-condition-dependent secondary lift of a gas exchange valve (5), for exhaust gas recirculation, which cooperates with a cam follower (2) supported on a hydraulic valve play adjuster element (4) and operated by a cam (6). The valve play adjuster element (4) is connected to a hydraulic medium supply path (12) and a hydraulic medium drain path (15) which may be closed by a sealing means (14), whereby a high pressure chamber (16) of the valve play adjuster element (4) is connected to the hydraulic medium drain path (15) by a through opening (22). The cam (6) has a cam projection (9) relative to a base circle (8) for the generation of a primary lift of the gas exchange valve (5) and a cam recess (10), into which the cam follower (2) descends on hydraulic extension of the high pressure chamber (16). In one mode of operation for the internal combustion engine, the primary lift and the secondary lift occur once the cam follower (2) reappears on the base circle (8) from the cam recess (10).