EXHAUST VALVE MECHANISM IN AN INTERNAL COMBUSTION ENGINE

摘要

Exhaust valve mechanism with a rocker arm (1) having a hydraulic circuit with a hydraulically operated valve play absorbing piston element (7). The hydraulic circuit contains a piston pump (20, 21) housed in the rocker arm and which is driven by an ordinary cam ridge (4) on the engine cam shaft (5). The piston (21) of the piston pump has a cam follower (23) spaced at a predetermined cam angle distance ( alpha ) from the ordinary cam follower (3) of the rocker arm. The pump is in communication via a channel (24) and intermediate regulator valve means (30) with the cylinder (6) of the valve play absorbing piston element. By means of the regulator valve means, the piston element (7) can be shifted to open the exhaust valve during a latter portion of the piston compression stroke to achieve so-called compression braking.