| 摘要 |
PURPOSE:To form in a compact size the construction variably forming the length of an intake passage, by providing a guide part, which guides a flow of air from an internal space to the intake passage in the downstream side, in the inner of a communication port connecting the internal space of a rotary structure, supported in a casing, with the intake passage in the downstream side. CONSTITUTION:An engine 1, when it is in operation, introduces air into a surge tank 3 to be further sucked into a combustion chamber 10 of each cylinder via each branch pipe 9 and an intake port 8. Further the air, being both introduced to an internal space 16 of a rotary structure 15 and distributed to each extension part 13 from a communication port 19 in the surge tank 3, passes in a swirl state through an intake passage 11 in the downstream side. And if a speed of the engine 1 increases, the engine, turning the rotary structure 15 in a direction (a) in the drawing, decreases a length of the intake passage 11 in the downstream side. Here in a condition that the engine 1 is in the maximum speed, a guide part 28, provided in an opening leading edge 19a of the communication port 19, agrees with the end part of an internal wall 12b of the passage. Accordingly, exfoliation of an air stream generated in the internal wall 12b of the passage can be suppressed. |
