FIELD: mechanical engineering; four-stroke internal combustion engines. SUBSTANCE: proposed device contains 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 furnished with seats for intake and exhaust valves and it is provided with intake and exhaust channels and intake and exhaust ports. Side surface of undervalve cup is provided with sealing members. Upper end face surface of undervalve cup has guide rod, holes for valve steams and hole connecting intake channel of undervalve cup with space between upper end face surface of undervalve cup and bottom of hole of undervalve cup. Combustion chamber is formed by piston crown, bottoms of undervalve cup, intake and exhaust valves and wells of hole of undervalve cup. At beginning of exhaust process, undervalve cup, with intake valve closed, is in extreme upper position, and opened exhaust valve is in extreme lower position. At completion of exhaust process, as piston approaches top dead center, undervalve cup, with closed intake valve, 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 closed intake and exhaust valve, is in extreme upper position. EFFECT: increased efficiency of engine, reduced fuel consumption, improved performance of engine and reliability of device. 9 cl, 3 dwg
