| 摘要 |
PURPOSE:To facilitate the interchange and inspection of exhaust valves in an overhead valve system reciprocating internal-combustion engine provided with a subcombustion chamber to which the exhaust valve is inserted from above by attaching removably an exhaust valve guide and the like to a cylinder head so that the exhaust valve can be removed toward the main combustion chamber side. CONSTITUTION:A subcombustion chamber pipe sleeve 3 is cold fitted in a pipe sleeve mounting hole 7 of a cylinder head 6 to afford communication between a main combustion chamber 10 and a subcombustion chamber 5 through a communicating port 1 of this pipe sleeve 3. An exhaust valve 2 is inserted in the subcombustion chamber 5 from the upper side and supported slidably in the cylinder head 6 through an exhaust valve guide 12. Then, the exhaust valve guide 12 has the external thread 12a screwed into the internal thread of a guide inserting hole 13 in the cylinder head 6. Also, the relationship between the stem diameter d2 of the exhaust valve 2, diameter D3 of the exhaust valve guide 12 and eccentricity epsilon of the communicating port center O1 to the exhaust valve stem center O2 is represented by (D3-d2)/2>epsilon and when the exhaust valve 2 is shifted until the center O1, O2 coincide with each other, the valve 2 can be removed toward the main combustion chamber 10 side. |
