Patent ID: 7421982

Claim:
An internal combustion engine for making suction, compression, explosion, expansion and exhaust strokes in an operating chamber of variable volume defined between a housing and a piston, said internal combustion engine comprising: an independent combustion chamber of fixed volume, formed in the housing and provided with a fuel supply device, for independently producing main combustion therein; at least one communication passage for communicating the independent combustion chamber with the operating chamber of variable volume; a control valve for allowing introduction of compressed air from the operating chamber into the independent combustion chamber and providing injection of combustion gas from the independent combustion chamber into the operating chamber at specified timing after a top dead center of a compression stroke; and the control valve being configured to close the communication passage within a predetermined range from near the top dead center of the compression stroke to approximately 20 to 30 degrees after the top dead center thereof such that the predetermined range includes the top dead center and a fuel injection from the fuel supply device is timed to occur in the predetermined range to thereby independently produce main combustion in the independent combustion chamber without communication with the operating chamber.