Piston and ring for reducing HC emissions

• Main Author: BREHOB, WAYNE M
• Format: Patent
• Language: English
• Published: 15.05.1979
• Subjects: ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES; BLASTING; COMBUSTION ENGINES; COMBUSTION ENGINES IN GENERAL; CYLINDERS; CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES ORMATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHERTHAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES; INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUSSUBCLASSES OF CLASSES F01-F04; INTERNAL-COMBUSTION PISTON ENGINES; LIGHTING; MECHANICAL ENGINEERING; PISTONS; SEALINGS; THERMAL INSULATION IN GENERAL; WEAPONS

An internal combustion engine is provided with pistons having openings connecting the space behind one of the piston rings with the crankcase during certain portions of the operating cycle of the engine. This is accomplished by the use of a differential pressure control valve that vents the unburned hydrocarbons trapped behind the compression ring to the crankcase during periods when the pressure in the combustion chamber is at the lower values during the internal combustion engine operating cycle. These unburned hydrocarbons are, therefore, directed into the crankcase of the engine rather than being permitted to leak back into the combustion chamber and to be discharged into the atmosphere during the exhaust stroke of the engine.