| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust system capable of effectively preventing reduction in exhaust efficiency, by changing the flow passage cross-sectional area of exhaust gas stepwise to an exhaust flow rate of a low speed, a medium speed and high speed rotation area of an internal combustion engine. SOLUTION: This exhaust system 1 has an exhaust introducing pipe 21 for introducing the exhaust gas from an engine, an expansion chamber 22 connected to a downstream end part of the exhaust introducing pipe 21, a main exhaust pipe 23 and an auxiliary exhaust pipe 24 connected to a downstream side wall of the expansion chamber 22, and an extension exhaust pipe 25 having a diameter smaller than the main exhaust pipe 23. The exhaust introducing pipe 21, the main exhaust pipe 23 and the auxiliary exhaust pipe 24 are inserted into the expansion chamber 22. The main exhaust pipe 23 is coaxially inserted into the exhaust introducing pipe 21 with a clearance, and the extension exhaust pipe 25 is coaxially inserted into the main exhaust pipe 23 with a clearance. A communicating port for exhausting the exhaust gas passing through the clearance with the extension exhaust pipe 25 to an external part, is formed in a downstream end part of the main exhaust pipe 23. COPYRIGHT: (C)2009,JPO&INPIT |
