| 摘要 |
PURPOSE:To prevent generation of knocking, by arranging the open timing of auxiliary intake and exhaust ports to an overlapped state while providing a timing valve opened and closed synchronously with an eccentric shaft in an auxiliary intake passage. CONSTITUTION:A supercharger 20 is provided in an auxiliary intake passage 19 to supply supercharge air from the passage 19 in addition to fresh air from a main intake passage 12 under a high loaded condition of an engine. Open timing of an auxiliary intake port 19a and exhaust port 29 is overlapped. A timing valve 30 opened and closed synchronously with an eccentric shaft 7 of the engine 1 is provided in the downstream of an auxiliary throttle valve 25 in the passage 19. An opening operational range of the valve 30 is set to be spread over an intake stroke end of the preceding working chamber 6 and the overlap timing of the port 29 and 19a in the following working chamber 6. In this way, geneneration of knocking can be prevented. |
