| 摘要 |
PURPOSE:To obtain compactness of an engine further reduce its noise, by providing a pipe branching from a long pipe, curved corresponding to an intake pulsation when the engine is at a low speed, and arranging said former pipe, equipped with a valve opened when the engine is at a high speed, to be extended in a reverse direction to said curved direction while providing a distributor box in the end of each pipe. CONSTITUTION:An intake pipe 19, having a pipe length corresponding to an intake pulsation when an engine is at a low speed, is curved in a flection part 17 in a reverse direction to that of an intake pipe 15, and the intake pipe 19 is equipped in its end with a distributor box 18. The engine, providing in an extending direction of the intake pipe 15 a pipe 21 equipped with a valve 23 opened when the engine is at a high speed, arranges a distributor box 20 in the end of the pipe 21. When the engine is at a high speed, a control unit 31, actuating a selector valve 29 and introducing negative pressure in a negative pressure chamber 27 to the chamber of a diaphragm 28 to open the valve 23, provides a pipe length corresponding to that in the time of high speed operation. In this way, the distributor boxes 18, 20, being arranged before and after the engine main unit 1, can form noise shielding parts in both directions, further the engine, arranging the distributor boxes to be divided into the front and the rear, obtains compactness.
|
