FIELD: mechanical engineering; four-stroke internal combustion engines. SUBSTANCE: proposed device contains cylinder, piston, cylinder head with intake and exhaust valves, movable cylindrical under-valve cup, camshaft with cam mechanism to operate intake and exhaust valves and drive mechanism of undervalve cup to regulate volume of combustion chamber. Device is furnished also with other drive mechanism for cleaning combustion chamber. Undervalve cup has seats for intake and exhaust valves and bushing installed on undervalve cup coaxially relative to intake valve seat. Cavity is made in cylinder head in intake manifold for displacement of bushing. Sealing members are fitted on outer sides of undervalve cup and bushing and at least one guide rod is made on side of undervalve cup opposite to piston. Combustion chamber is formed by piston crown, bottoms of undervalve cup, intake and exhaust valves and walls of hole of undervalve cup. At minimum loads of engine and at starting, undervalve cup shifts towards piston, thus providing minimum volume of combustion chamber, maximum compression ratio, minimum stroke of intake valve and minimum charge (air or fuel-air mixture). At increase of engine load, undervalve cup shifts to side opposite to piston under action of spring, thus increasing volume of combustion chamber, decreasing compression ratio and increasing stroke of intake valve and amount of taken-in charge and clearance compensators decrease value of clearance. At nominal engine load, undervalve cup shifts in to extreme upper position relative to piston, thus providing increase of volume of combustion chamber, travel of intake valve and working charge to maximum value and decrease of compression ratio to minimum value. EFFECT: increased efficiency of engine, reduce consumption of fuel, improved performance of engine and reliability of device. 23 cl, 2 dwg
