FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: new method of compression of air-fuel mixture till moment of ignition in one combustion chamber by means of working piston and air-fuel mixture aftercompression piston in which cylinder spaces are in constant communication with combustion chamber space and piston of compressor in which cylinder space is separated from combustion chamber space is proposed. According to said method air-fuel mixture in combustion chamber is compressed till the moment when working piston reaches top dead center, and aftercompression of air-fuel mixture till moment of ignition is provided only by aftercompression piston after passing of top dead center by working piston. It prevents untimely knocking and provides effective usage of high-pressure hot gases as these gases act onto working piston of reduced diameter in corresponding of reduced diameter at provision of lever acting onto axle of crankshaft at moment of ignition of air-fuel mixture compressed to maximum value at the time when aftercompression piston provides minimum volume of combustion chamber from moment of ignition of air-fuel mixture compressed to maximum value to moment of exhaust of waste gases. EFFECT: reduced consumption of fuel. 5 cl, 3 dwg
