| 摘要 |
PROBLEM TO BE SOLVED: To provide an intake system that enables reduction in pressure loss caused by a valve and enhancement of flow velocity of air on the downstream side of the valve and can be easily installed.SOLUTION: An intake pipe 7 of this intake system 1 is constituted by integrally forming a valve arrangement portion 15 in which a valve 9 is arranged, an upstream side portion 16 continuing to the upstream side of the valve arrangement portion, and a downstream side portion 17 continuing to the downstream side of the valve arrangement portion. A step portion 19 recessed toward the outer peripheral side of the intake pipe is formed on an inner peripheral wall 7a extending over the valve arrangement portion and the downstream side portion of the intake pipe. An intake passage formation member 21 forming the intake passage 8 is arranged in the step portion. The intake passage formation member includes an intake passage formation surface 21a that forms the intake passage so that a maximum passage area S1 (Sa-Sb) of the valve arrangement portion is made approximately equal to a passage area S2 of the upstream side portion and so that a minimum passage area S3 of the downstream side portion is made smaller than the maximum passage area S1 of the valve arrangement portion.SELECTED DRAWING: Figure 3 |
