| 摘要 |
PROBLEM TO BE SOLVED: To reduce HC emission by an insulation effect of an insulating layer, immediately after starting an engine by disposing heat insulating means a heat insulating space provided between metal plates, which are joined to a fuel colliding part on the top surface of a piston which is subjected to a fuel blow. SOLUTION: An insulating member 20 is provided on a recess part formed on the top surface of a piston 5 corresponding to the shape thereof. The insulating member 20 comprises a pair of metal plates 21, 22, such that one metal plate 21 is provided uniformly with many holes 23 having a bottom and a round cross section. For the other metal plate 22 bonded thereto, air is sealed in the holes 23. The other metal plate 22 is made of a heat resistant stainless steel plate, formed with a thickness smaller than the metal plate 21. It is preferable that the metal plate 22 have low specific heat and is made as thin as possible. The insulating member 20 is bonded and fixed to the recess part of a cylinder head through thermal spraying on the bottom surface of the metal plate 21 and by a high-pressure casting method.
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