| 摘要 |
PURPOSE:To dissolve the influence generated by back-blow of such as fresh air toward a supercharger, so as to reduce the drive loss and to raise the output, by setting check valves adapted to check a counter-blow of fresh air toward the pressure-charging means side, and setting a driving mechanism adapted to open exhaust valves earlier than intake valves. CONSTITUTION:In heavy load range of an engine, an intake air control valve 16 is opened, and on the other hand, an exhaust gas control valve 34 is closed. Then, exhaust valves 31a, 31b are opened according to the descendent motion of a piston, to blow-out the exhaust gas abruptly. Next, suction vales 21a, 21b are opened to blow-in the fresh air from suction ports 20a, 20b toward a combustion chamber 2, respectively, and by this matter, cross scavenging is performed by the exhaust gas and the fresh air. At this time, a counter-blow of the fresh air is prevented by check valves 18a, 18b. Next, a part of the fresh air is stored in exhaust ports 32a, 32b and an exhaust manifold 33 for a while, by exhaust pulse effect, and after that, the stored fresh air is pushed into the combustion chamber 2 as this fresh air is blown back. At this time, dynamic pressure which acts on intake ports 20a, 20b is checked by the check valves 18a, 18b, respectively. |
