| 摘要 |
PURPOSE:To improve stability of idle combustion by providing a downstream throttle valve at independent intake passages provided independently from cylinders, providing an upstream throttle valve at a collection intake passage, and openly and closely controlling the throttle valves according to a load condition on an engine. CONSTITUTION:To an intake port 3 opened to each cylinder 2 of a three cylinder engine, independent intake passage 4a-4c are connected. The upstream ends of the passages 4a-4c are collected to a collection intake passage 4. At the upstream side, an air flow meter 6 and air cleaner 7 are provided. downstream throttle valves 8 are arranged at the independent intake passages 4a-4c at the downstream side in the vicinity of an intake port 3. An upperstream throttle valve 9 is arranged at a collection intake passage 4 in the vicinity of the collection part of the upperstream side thereof. These valves 8, 9 are controlled in their opening and closing by an opening and closing device 12 interlocking with operation of an acceleration pedal 11 in a manner to throttle intake air with the downstream throttle valve 8 at the time of low load while with the upstream throttle valve 9 at the time of high load. |
