PISTON COOLING STRUCTURE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a piston cooling structure for an internal combustion engine for preventing damage by mechanical stress without increasing a manufacturing cost. SOLUTION: This piston cooling structure for the internal combustion engine is applied to a cylinder direct injection internal combustion engine for injecting fuel into a cavity 13 arranged in the upper surface center of a piston 11 from respective nozzle ports on the tip of an injector, and touches a flame to plural places corresponding to the respective nozzle ports of a lip part 16 on the peripheral edge of the cavity. In the setting for touching the flame to a rear side part 17 of the lip part 16, an oil inlet 20 of a cooling channel 19 extending in an annular shape in an upper part of the piston 11 is arranged in a rear side area A on the anti-thrust side in the upper part. A temperature rise of the flame touching rear side part 17 can be prevented by low temperature oil entering from the oil inlet 20 to thereby prevent a part generating maximum mechanical stress from becoming a high temperature by the flame.