FIELD: mechanical engineering. SUBSTANCE: proposed internal combustion engine has housing, at least one cylinder with cover, piston arranged in cylinder, power rod connected with piston, shaft with at least two side and at least one middle cams. Power rod is made for engagement through its working surface with middle cam located on shaft between side cams. Piston is furnished with two auxiliary rods made in form of frames with slots in form of rectangles with rounded off upper and lower bases, bulges on external sides of frame engaging with corresponding guide slots of housing, stiffening ribs made on inner surfaces of slots and working surfaces engaging with end face surfaces of side cams. Profile of face working surfaces of side and middle cams is made to provide, in angle of shaft turning, distance between end face working surface of middle cam engaging with power rod and end face working surfaces of side cams engaging with auxiliary rods equal to distance between working surfaces of power and auxiliary rods. Grooves are made on shaft to receive stiffening ribs of auxiliary rods. EFFECT: increased efficiency, reduced fuel consumption and increased service life of cylinder-piston mechanism units of engine. 4 cl, 11 dwg
