| 摘要 |
PROBLEM TO BE SOLVED: To surely lubricate a portion above openings of scavenging ports of a cylinder inner wall face, reduce consumption of lubricating oil, and prevent degradation in exhaust gas, in a two-cycle internal combustion engine in which the openings of the scavenging ports 5 in the inner wall face 2a of the cylinder 2 are opened when a piston 4 moves down near a bottom dead center to supply lubricating oil to a lower side of the cylinder inner wall face 2a than that of a case that the piston is at a top dead center. SOLUTION: Out of the cylinder inner wall face 2a below a lower edge of the openings of the scavenging ports, an area of overlap stroke section W, in which piston rings 8 of an upper end of an outer periphery of the piston overlaps with oil rings 9 of a lower end of the outer periphery of the piston by reciprocation of the piston, is provided with the infinite number of dimples. Or the surface roughness of the area of the overlap stroke section W is greater than that of the other area. COPYRIGHT: (C)2006,JPO&NCIPI
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