| 摘要 |
<p>PURPOSE:To ensure sufficient negative pressure at all times, in an engine provided with first and second throttle valves respectively in a common intake path and an independent intake path, by arranging an intake negative pressure take-in port for each negative pressure utilizing means in an independent intake path in the downstream of the second throttle valve. CONSTITUTION:A surge tank 15 is coupled to the downstream side end section of a common intake path 11 arranged with a first throttle valve 14 interlocked with an accelerator pedal to be opened/closed. An independent intake path 4 coupled with respective intake ports 3 of first to fourth cylinders is branched and coupled with the surge tank 15. Second throttle valve 18 which is controlled to close side in order to prevent counter-flow of exhaust gas into the independent intake path 4 in final stage of exhaust stroke under predetermined light load is arranged in each independent intake path 4. In such engine 1, a negative pressure tank 25 is coupled as a negative pressure source for various negative pressure utilizing means to the surge tank 15 through a first negative pressure lead-in path 26 and to each independent intake path 4 in the downstream of through the second throttle valve 1 through a second negative pressure lead-in path 31.</p> |
