PISTON AND RING FOR REDUCING HC EMISSIONS

摘要

PISTON AND RING FOR REDUCING HC EMISSIONSABSTRACT OF THE DISCLOSUREAn internal combustion engine is provided withpistons having openings connecting the space behind one ofthe piston rings with the crankcase during certain portionsof the operating cycle of the engine. This is accomplishedby the use of a differential pressure control valve that ventsthe unburned hydrocarbons trapped behind the compression ringto the crankcase during periods when the pressure in thecombustion chamber is at the lower values during the internalcombustion engine operating cycle. These unburnedhydrocarbons are, therefore, directed into the crankcaseof the engine rather than being permitted to leak back intothe combustion chamber and to be discharged into theatmosphere during the exhaust stroke of the engine.