FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: proposed internal combustion engine has two cylinder-piston groups, each provided with irregular shape eccentric ensuring normal operation of air-fuel mixture aftercompression mechanism to suit cycle of operating piston. Aftercompression mechanism guarantees timely ignition of air-fuel mixture and, together with pyramidal piston consisting of piston-stroke stabilizer - antifire separator and reduced diameter operating piston arranged in corresponding cylinders provides effective usage of high pressure hot gases in reduced volume of operating cylinder. Operating volume of this cylinder provides less than half of required air-fuel mixture compression ratio in combustion chamber. EFFECT: provision of fuel economy owing to effective use of high pressure hot gases. 7 cl, 5 dwg
