| 摘要 |
<P>PROBLEM TO BE SOLVED: To sufficiently reduce exhaust noise in the idling of an internal combustion engine in an outboard motor. <P>SOLUTION: The outboard motor comprises a case 8 supportable on a hull and the internal combustion engine 10 supported on the upper surface of the case 8. The case 8 comprises a guide exhaust 18 forming the upper part thereof and an oil pan 20 fitted to the lower surface of the guide exhaust 18. Exhaust gas 13 exhausted from the internal combustion engine 10 is led from the upper end part to the lower end part of the case 8, and an exhaust passage 30 for exhausting from the lower end part into water 2 is formed in the case 8. A branch passage 31 for exhausting the exhaust gas 13 in the exhaust passage 30 to the atmosphere is formed in the case 8 by branching the exhaust passage 30 from the intermediate part thereof in the longitudinal direction. An expansion chamber 37 is formed at the intermediate part of the branch passage 31. The expansion chamber 37 in the branch passage 31 is formed between the guide exhaust 18 and the oil pan 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
