Patent ID: 6394054
Filing Date: 2002-05-28
Classification: F01L,F02B

Abstract:
A four-stroke internal combustion engine, comprising:a cylinder block including a cylinder therein and having a piston reciprocally disposed within said cylinder, said piston operably engaged with a crankshaft; a camshaft; at least one intake valve reciprocally driven by said camshaft; at least one exhaust valve reciprocally driven by said camshaft; and a vacuum release mechanism, comprising: an operating member rotationally supported by said camshaft and including an operator disposed thereon; a centrifugally actuated flyweight member attached to said operating member, wherein rotation of said camshaft above engine cranking speeds causes said flyweight member to rotate said operating member from a first position to a second position; and a vacuum release member reciprocally supported by said camshaft and in engagement with said operator wherein rotational movement of said operating member causes radial translation of said vacuum release member through said operator, said operating member and flyweight urged to said first position at engine cranking speeds and rotated by said flyweight member through centrifugal force to said second position at engine running speeds; said vacuum release member being in lifting engagement with one of said valves at said first position during at least a portion of the power stroke of said piston and out of lifting engagement with one of said valves at said second position.