| 摘要 |
PURPOSE:To improve the combustion efficiency by permitting the uniform and speedy temperature rise of a surface part by forming a high thermal conductivity layer onto the surface part which is made of ceramics and faced to a combustion chamber in a piston body made of light alloy. CONSTITUTION:A piston is made of the light alloy containing Al and Mg as main constituents and equipped with a piston head part 10 having a combustion chamber at the center part, side surface part 20 which moves in sliding with the cylinder inner wall surface, and a hollow part 30 for holding a connecting rod. The wall 110 of the combustion chamber is made of ceramics. With such structure, each high thermal conductivity layer made of the pure copper in the uniform thickness of 2mm is formed onto all the surfaces of the side wall part 111 and bottom wall part 112 of a combustion chamber 100 in the piston head part 10 and the peripheral edge part 200 in the upper part of the combustion chamber through plasma metallization. At this time, the high thermal conductivity layer is made of the material having the thermal conductivity higher than that of the light alloy which forms the piston. |
