| 摘要 |
PURPOSE:To improve combustion and prevent suction air from flowing back from a combustion chamber to a suction passage at a low speed run of an engine with the aid of suction swirl by providing a reed valve in a main suction passage at a position between opposite ends of an auxiliary suction passage. CONSTITUTION:At a low load run of an engine with a throttle valve 40 in almost fully closed position, suction air passes through an auxiliary suction passage 42 and is then blasted inside a main suction passage 34 adjacent to a suction valve 18 to produce an intense suction swirl inside a combustion chamber 16 due to the appropriate trend of recovery given to a reed valve 56. When the throttle valve 40 is gradually opened as a load increases, the flow rate and the flow velocity of suction air which passes through the auxiliary suction passage 42 become higher, hence resulting in higher suction resistance. When a suction resistance inside the auxiliary suction passage 42 reaches the resistance of the reed valve 50, the reed valve 50 is opened to permit suction air to flow from the main and the auxiliary suction passage 34 and 42 into the combuston chamber 16. |
