FIELD: manufacture of engines. SUBSTANCE: proposed engine operates as four-stroke internal combustion engine at reduced and average speeds of crankshaft and automatically shifts to two-stroke cycle when speed exceeds average value. Engine includes scavenging pump, intake plate valve, fuel supply accumulating system with spool valve proportioner and emulsion-type unit injector, camshaft rotating at half speed of crankshaft and having cam plate with four cams of different profiles, hydromechanical drive of intake valve and unit injector with one plunger pump driven by cam plate and hydraulic control system with control member. Automatic change of stroke is effected by means of hydromechanical drive. EFFECT: increased power, enhanced efficiency, simplified construction and multi-fuel operation. 16 cl, 8 dwg
