Patent ID: 7886714

Claim:
An exhaust gas reflux mechanism of a multipurpose engine, comprising: an intake valve which opens and closes to provide communication between an intake port and a combustion chamber, an exhaust valve which opens and closes to provide communication between an exhaust port and the combustion chamber, a single cam provided on a camshaft disposed above said combustion chamber, said single cam being driven to open and close the intake and exhaust valves in timed relation to each other, wherein an exhaust reflux cam is formed integrally with the single cam as an integral part of the single cam and has a cam lobe profiled to open the exhaust valve while the intake valve stays open during an intake stroke of the engine, so that a reflux of exhaust gas into a combustion chamber of the engine occurs during the intake stroke, and wherein an engine speed of said multipurpose engine automatically increases to a predetermined operating speed after a start-up of the engine.