Variable lift valve mechanism in IC engine - reduces lift of inlet valve in accordance with increase in suction pressure

摘要

The inlet valve (12) is operated by a rocker arm (14) against the action of the closing spring (13). The rocker arm is moved by a push rod (20) which is lifted by a cam (16). An adjusting lever (22) has an end (23) between the push rod and the rocker arm. This end is spherical. The other end is pinned (28) to an eccentric (29) on the end of an operating lever (32) whose other end is connected to the piston (34) of a membrane actuator (35). The actuator is subjected to the manifold suction presure so that when the pressure increases the operating lever (32) moves the adjusting lever (22) so that the point of contact (P) on the rocker arm moves to reduce the valve opening lift.