| 摘要 |
PURPOSE:To enhance heat insulation capability, to enable the working step of removing sand to be omitted and to prevent deformation, crack or the like of the exhaust port liner due to thermal strain by slidably supporting the unsecured side end part of the exhaust port liner, and by forming an annular projection for allowing a heat insulating layer to be sealingly enclosed. CONSTITUTION:The end part 20a of an exhaust port liner 20 on the side of a combustion chamber 10 is partly inserted into and secured to a cylinder head 14, and an insulating layer charged with an insulating material 18 is formed, sorrounding around an exhaust port 16. In the inner peripheral surface of the exhaust port of the cylinder head 14 in the vicinity of the exhaust port outlet side end part 20c of the exhaust port liner 20 which corresponds to the unsecured side end part of the exhaust port liner 20, an annular projection 22 capable of sealingly enclosing the exhaust port outlet side end part 18b of the insulating layer charged with the insulating material 18 and having a width (1) is formed for slidably supporting the exhaust port outlet side part 20c of the exhaust port liner 20. |
