| 摘要 |
The low noise level combustion engine comprises a cylinder block without a skirt portion, a supporting member for supporting a journal of the crankshaft, the supporting member being fixed to a lower end portion of the cylinder block. A shroud suppresses an explosion sound in a cylinder and a bearing sound to be radiated out of the engine, the shroud being integrally formed with a cylinder head fixed to an upper side of the cylinder block whereby the shroud is spaced from the cylinder block. There is a noise insulating member disposed between the shroud and an oil pan, for increasing a flexural rigidity of the shroud and oil pan and decreasing noise. The shroud includes an upper portion aligned with said cylinder block, a lower expanded portion extending from the upper portion, and a number of ribs integrally formed with the upper and lower portions of the shroud to increase the rigidity of it. |
