| 摘要 |
<p>PURPOSE:To reduce the peak of the exhaust noise in a discharge port by joining respective exhaust gases discharged from cylinders not adjacent to each other in terms of the ignition order, allowing them to flow into two exhaust systems, different in acoustic passage length from each other, and joining them discharged from the exhaust systems at the discharge port. CONSTITUTION:A manifold 6 has branch pipes 1 and 4 connected with cylinders Nos. 1 and 4 respectively, and a manifold 7 has branch pipes 2 and 3 connected with cylinders Nos. 2 and 3 respectively. The manifolds 6 and 7 are connected with front tubes 8 and 9, catalysts 10 and 11, center tubes 12 and 13, mufflers 15 and 16, and tail tubes 17 and 18, respectively. The center tube is substantially formed of a double tube 14 composed of inside and outside center tubes 12 and 13. The tail tubes 17 and 18 are made to be in proximity with each other in their opening portions to the atmosphere. Therefore, the exhaust noise is cancelled to each other in its 0.5 order component of the engine speed at the joining point of the manifolds 6 and 7. Furthermore, at the joining point of the discharge port, the exhaust noise is cancelled in its primary order component of the engine speed, thus reducing the peak of the exhaust noise at the discharge port.</p> |
