| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston for an internal combustion engine, having improved cooling performance, in which in addition to a cooling fin, a cooling hole extending from a cooling hollow on a back surface of a piston head toward a top surface of a piston is formed additionally, sodium is included in the cooling hole, and thus heat on the top surface of the piston is transferred to the cooling hole. SOLUTION: In a piston 10 for an internal combustion engine, at least one cooling fin 40 is attached to a back surface of a piston head 22. Further, at least one cooling hole 22F extending from an inner wall of a cooling hollow 22E for circulating lubricant oil sprayed from an oil jet toward a top surface of the piston is created. Sodium 50 is filled in the cooling hole, opening of which is blocked with a plug (hole cap) 22G. Then, in addition to piston cooling by the cooling fin 40 and the cooling hollow 22E, heat on the top surface of the piston is transferred to the cooling hole 22E using the sodium liquefied in the cooling hole 22F as a heat transfer medium. This improves a cooling performance of the piston. COPYRIGHT: (C)2009,JPO&INPIT
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