| 摘要 |
PURPOSE:To reduce exhaust noise at the time of idling and low-speed operation by installing a guide wall at the upper part of a rear expansion chamber, forming a circulatory exhaust passage which dampens exhaust gas by expansion and compression. CONSTITUTION:Within a chamber 20, a rear expansion chamber 34 is composed of a bulkhead 17, the outer wall 19 of a casing and water surface. At the upper part of the rear expansion chamber 34, a guide wall 35 is formed between the bulkhead 17, and an inner wall 36 installed on the outer wall 19. Due to the guide wall 35, circulatory exhaust passages 37, 38 are formed in the upper part of the rear expansion chamber 34. Thus, exhaust gas discharged from the 3rd expansion chamber 25 of an exhaust guide 9 is led through the circulatory exhaust passage 37 to the rear expansion chamber 34, and after being circulated there, guided through the circulatory exhaust passage 38 on the opposite side, and a restriction groove 39, formed on the inner wall 36, eventually to a passage 31 with these routes comprising part of an auxiliary exhaust passage. |
