| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the service life of an outboard engine by preventing chemical reaction between water and sulfur content in exhaust gas, when an exhaust passage for passing the exhaust gas from an internal combustion engine in the outboard engine is formed in a case and the case is cooled by water. <P>SOLUTION: This water-cooling structure comprises the case 8 that can be supported by a hull and of which lower side can be immersed into water 2 and the internal combustion engine 10 supported on the upper surface of the case 8. The exhaust gas 13 exhausted from the internal combustion engine 10 is guided from the upper end side to the lower end side of the case 8, and the exhaust passage 30 for exhausting it from the lower end side into the water 2 is formed in the case 8. An intermediate section between the upstream passage and a downstream passage 34 in the exhaust passage 30 is used as an expansion chamber 36, and a cooling water passage 52 extending along the exhaust passage 30 is formed in the case 8. A drainage port 66 for draining the water 2 after passing the cooling water passage 52 to the downstream passage 34 is opened in the downstream passage 34. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
