| 摘要 |
PURPOSE:To simplify the structure of a suction manifold as well as to secure the stabilization of combustion, by setting up the opening region of each jet port of a low-load suction passage at an almost backside position of a suction valve, in case of a muticylinder engine equipped with a twin carburetor. CONSTITUTION:A suction system ranging from a twin carburetor 1 to each cylinder is divided into two systems, a low-load suction passage 14 and a couple of high-load suction passages 161 and 162. In addition, the low-load suction passage 14 is ramified to each of cylinders at the inside of a cylinder head 4 or a connecting part. And, an opening region for each suction port of the branched jet ports 111 and 112 are set up at an almost backside position of each suction valves 71 and 72. Since a single low-load suction passage 14 is to be used for every cylinder in common, not only suction manifold 12 can be simplified in structure but the setting space required can be reduced. Likewise, a variation of air-fuel ratio at the low-load and low-speed rotation zone can be lessened and responsiveness to acceleration can be improved. |
