| 摘要 |
PURPOSE:To provide high charging efficiency by shutting off a branch passage at a low-speed and low load run of an engine to have an ample flow of mixture fed along the upper wall face of a helical part, generating an intense swirl in a combustion chamber, and by opening the branch passage at a high-speed and high-load run thereof to supply a great amount of mixture. CONSTITUTION:At a low-speed and low-load run of an engine, a rotary valve 25 is kept closed so that some of mixture flows along the upper wall 19 and 20 while a part of the rest runs against the rotary valve 25 and is turned towards the side wall face 17, generating a swirled flow. At a high-speed and low-speed run thereof, the rotary valve 25 is opened so that the mixture flows between the first side wall face 14a and a side wall face 17 in the form of three streams, one along the upper wall face 20, the next one led by branch passage 24 and the lost one along the bottom wall face 21. In the section view of a suction port 6 at the proximity to a switching valve, the height of a separation wall 12 is made approximately a half of that of the suction port 6. |
