Variable lift valve drive - adjusts piston surface area presented to pressure in pressure chamber

摘要

Between a lift valve and the cam (2) which operates it there is a system for the transmission of hydraulic power (3). This consists of a pump piston (4) at the cam end and a piston (5) at the valve end of a pressure chamber (6) containing a compression spring (7). A control valve (14) is linked to the pressure chamber (6). The piston (5) at the valve end has several surfaces which are acted upon by the pressure in the pressure chamber (6). At least one of these surfaces (10) can be connected and disconnected by the control valve (14) in order to adjust transmission ratios. USE/ADVANTAGE - Allows accurate adjustment of valve timing.