| 摘要 |
PURPOSE:To make the wall temperature of a combustion chamber higher so as to prevent an ignition lag by providing a surface layer which consists of ceramics sintered body and a heat insulating elastic layer which surrounds the outer peripheral surface side of the surface layer to form a recessed part, in a piston head in which the recessed part is provided. CONSTITUTION:A recessed part 2 is provided in the piston head of a piston 1 for an internal combustion engine. The recessed part 2 has a three layer structure which comprises a surface layer 3 that consists of ceramics sintered body, a heat insulating elastic layer 4 that consists of non-metallic inorganic porous body and surrounds the outer peripheral surface side of the surface layer 3, and a metal cast body 5 for forming the piston main body that is cast around the heat insulating elastic layer 4. The non-metallic inorganic porous body, which composes the heat insulating elastic layer 4, has low thermal conductivity and sufficient elasticity which can ease thermal stress that is generated by the difference of the coefficient of thermal expansion between the surface layer 3 and the metal cast body 5. Porous ceramics compact is preferably a non-metallic inorganic porous body. The surface layer 3 has divided structure which consists of two members 3a, 3b. |
