| 摘要 |
PURPOSE:To minimize the head clearance in a squish region and to reduce the HC by coating the wall surface of a combustion chamber forming the squish region with a specific coating layer in said structure provided with the squish region in the combustion chamber when a piston is at the upper dead point. CONSTITUTION:The portion (space section) provided with a suction port 7 and plug hole 10 below a cylinder head 3 is recessed upward more than other portion (slant line section). Accordingly, a combustion chamber 5 is divided into a main combustion chamber 5a inflaming the intake air with the recessed portion of the cylinder head 3 serving as an upper wall and a squish region 5b forming a squish current with other portion than the recessed portion acting as the upper wall. In this case, a porous thermal-resistant polyester resin layer 11 containing 5-50wt% of Al is formed by flame coating on the top surface of the piston 4 corresponding to the squish region 5b. Thereby, the combustion speed is increased, the quench volume is decreased, and the HC is reduced. |
