| abstract |
An internal combustion engine in which a cylinder liner and a piston ring which slides along the inner peripheral surface of the cylinder liner is used in combination, characterized in that the cylinder liner is made of cast iron or steel and has an iron oxide layer mainly of Fe 3 O 4 with Fe 2 O 3 and FeO contents at least on a part of the inner circumferential surface, and the piston ring used in combination, at least on a sliding surface that slides along the cylinder liner, having a layer of either a Cr-BN alloy, a Ti-N alloy or a Cr-BVN alloy. |