| 摘要 |
PURPOSE:To provide high charging efficiency by preventing gum-like impure substance from depositing on a valve body while preventing the mixture from leaking into a branch passage at a low-speed and low-load run of an engine to aid formation of an intense swirl inside a combustion chamber and by opening and the branch passage to feed an ample flow of mixture into a helical part at a high-speed and high-load run thereof. CONSTITUTION:At a low-speed and low-load run of an engine, a rotary valve 25 is kept closed. Some of mixture sent into an inlet passage flows forward along the upper wall face 19 and 20, and a part of the rest runs against the rotary valve 25 and turns to flow along the side wall face 17. Since a part of the mixture flows against a valve body 31, if clearances between an edge 31a of the valve body 31 and a side wall face 27 and between opposite edge 31b of the valve body 31 and the second side wall face 14b are completely closed, gum-like impurities within mixture are deposited between valve body edges 31a, 31b and between the wall faces 27, 14b. For those purposes of preventing deposition of impurities and leakage from the clearance l1 and l2, annular recess 36 and 37 are formed. |
