| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an oil passage structure capable of restraining the temperature of oil from locally being raised by preventing the stay of cooling oil even if a projection exists in a cooling oil passage of a cylinder head, in an air-oil cooled internal combustion engine. <P>SOLUTION: The oil passage structure of the air-oil-cooled internal combustion engine 1 includes a crankcase 10, a cylinder 12 and a cylinder head 13 for installing and storing a valve train 60. A head side cooling oil passage 7 is arranged in the cylinder head. A projection 75 branching off from the head side cooling oil passage is formed at an intermediate part of the head side cooling oil passage. The oil passage structure of the air-oil-cooled internal combustion engine is characterized by arranging a bypass passage 97 communicating with the downstream side of the head side cooling oil passage from an end of the projection and having the passage cross-sectional area smaller than that of the head side cooling oil passage. <P>COPYRIGHT: (C)2013,JPO&INPIT |
