| 摘要 |
PURPOSE:To perform coexistence of hardening treatment and nontreatment layers in the internal surface of the captioned cylinder, while utilize a feature of improving wear resistant and scuffing resistant characteristic further perform simultaneous reduction of oil consumption and blow-by gas. CONSTITUTION:A belt shaped hardening treatment layer 1 is circumferentially provided to the internal peripheral surface of a cylinder and formed in such a manner that at least two stripes of said belt-shaped hardening treatment layers 1 mutually cross in spiral states 1, 1a.... In this way, the hardened treatment layer 1 can surely surround non-treatment layer 2, and the non-treatment layer can be independently separated in an island state. Accordingly, the increase of oil consumption and blow-by gas, caused after the middle period of an engine life from a demerit of simple spiral shape or dotted shape, can be remarkably suppressed. |
