| 摘要 |
PURPOSE:To have a relatively large exhaust hole with its exhaust noise suppressed effectively, by furnishing a comparatively large number of expansion chambers for the exhaust gas, by introducing part of the cooling water to this exhaust gas and then exhausting the mixture. CONSTITUTION:During trolling operation, exhaust gas from the engine is sent as shown by arrows from a cylinder 11 to an under-cover 12 and exhaust tube 13 to be introduced into an expansion chamber passing underwater. This exhaust gas is then sent to another expansion chamber 16 through a communication line 18,and further to an expansion chamber 17 through another communication line 19. The cooling water for engine is sent as shown by the double arrow indication from a drainage 26 to another 27, and further to outside the motor through a drain hole 20. Part of the drain water thus introduced into the drainage 27 is sent to the abovementioned expansion chamber 17 through a communication line 29, where it is mixed with the exhaust gas to be exhausted together to outside the motor from exhaust hole 20. Exhaust noise can be suppressed by thus exhausting the exhaust gas upon being mixed with part of the drain water. |
