| 摘要 |
PURPOSE:To accelerate a suction flow velocity at the latter half of a suction stroke as well as to prevent suction air out of a cylinder from flowing back, by installing a passage controlling device, narrowing a passage sectional area toward a port by degrees in time of the latter half of the suction stroke, in and around the suction port at the downstream of a suction passage. CONSTITUTION:At the downstream of a suction pipe 18 interconnecting a suction port to be opened or closed by a suction valve 8, there is provided with a passage controlling device 19 whose ont end rotates centering on a shaft 20, and it is rocked by a rod 24 reciprocating with a shaft 21 being rotated by a gear 25 interlocking with rotation of an engine. The passage controlling device 19 is rocked up and down in the latter half period of a suction stroke in which a suction valve 8 is opened, and it narrows the suction passage at the period that at the latter half period of suction, a suction flow velocity to a cylinder becomes weakened whereby reflux to the suction passage is going to occur, so that the suction flow velocity will not be weakened, thus any backflow is prevented from occurring. |
