FIELD: mechanical engineering; four-stroke internal combustion engines. SUBSTANCE: proposed device contains cylinder, piston, cylinder head with intake and exhaust valves, movable cylindrical undervalve cup, camshaft with cam mechanism to operate intake and exhaust valves and drive mechanism of undervalve cup. Undervalve cup is provided with seats for intake and bushing installed on undervalve cup coaxially relative to intake valve seat. Cavity for displacement of bushing is made in cylinder head in intake manifold. 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 valve and walls of hole of undervalve cup. At beginning of exhaust process, undervalve cup, intake valve closed, is in extreme upper position, and opened exhaust valve is in extreme lower position. At completion of exhaust process, when piston approaches top dead center, undervalve cup, with intake valve closed, shifts into extreme lower position, thus evacuating exhaust gases from combustion chamber and decreasing clearance (dead) volume of combustion chamber. At beginning of intake stroke, undervalve cup shifts into extreme upper position with intake valve opened in extreme lower position. At end of suction process, intake valve shifts into extreme upper position and closes. In process of compression and during working stroke, undervalve cup, with intake and exhaust valves closed, is in extreme upper position. EFFECT: increased efficiency of engine, reduced fuel consumption, improved performance of engine and reliability of device. 9 cl, 2 dwg
