Compression release mechanism

摘要

A compression release mechanism for use in a single or multi-cylinder engine to make the engine easier to hand start. The assembly includes a compression release shaft disposed substantially within the camshaft. The compression release shaft is formed in at least two segments and can therefore be formed accurately, repeatedly and cost effectively using powder metal technology. Consequently, the weight of the flyweight member that is attached to the compression release shaft can be accurately controlled, thereby allowing the compression release mechanism to disengage at a precisely known rotational velocity of the camshaft. The compression release shaft may engage one or more valve actuation devices, which in turn force exhaust valves open during starting engine speeds. The compression release mechanism is conveniently contained within the housing by a housing wall bearing against the flyweight member and a cam bearing against an end of the compression release shaft. These bearing surfaces also hold the compression release shaft segments together.