| 摘要 |
PURPOSE:To prevent silencing effect from decreasing despite the silencer's capacity shortage by filling acoustic material in an air chamber connected to a manifold and formed in between outer and inner tubes of a double tube section which consists of said outer and inner tubes and follows right after the downstream end of the mainifold of exhaust tubes. CONSTITUTION:The high temperature, high pressured exhaust out of the cylinders is led through each exhaust pipe 4a-4d into exhaust manifold 6, collected at a manifold 12 to go on through a manifold tube 7 to 2 silencer, where it is silenced and discharged into the atmosphere. An air chamber 19 filled with acoustic material is so formed as it covers closely the outside of the downstream of the manifold 12. The internal tube 14, forming a double tube section 13 set right after the downstream end of the manifold 12, is made of porous plate or punching metal which makes it possible to form lots of through holes all over the metal plate to provide communication from the manifold 12 to the air chamber 19. Thus, the exhaust pressure wave is effectively damped even upstream from the silencer to get a satisfactory performance as expected.
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