Valve gear for a cam-actuated lifting valve fitted with closing spring

摘要

For obtaining a transmission ratio between cam (38) and valve (37) a valve gear for a lifting valve (37) contains a pressure chamber (32) in a component (30) designed for the introduction of the valve actuating forces of the cam (38), which chamber transmits the valve opening forces by way of a valve actuating piston (34), displaceable in the valve actuating direction, and a further pressure chamber (33), which is defined by a fixed displacement piston (35). The displacement piston (35) has a larger piston surface than the valve actuating piston (34), so that in valve opening movements pressure medium is transported out of the further pressure chamber (33) into the pressure chamber (32) by way of a connecting passage (31), displacing the valve actuating piston (34) in the valve opening direction. As a result, a higher valve lifting curve is obtained than inherently predetermined by the cam path. By restricted removal of pressure medium from the further pressure chamber (33) when a valve (41) is in the opened position, the valve lifting curve can moreover be influenced as a function of the engine speed (Fig. 3). <IMAGE>