REDUCTION OF PISTON SKIRT FRICTION USING THE MICRO-SCALE PATTERNED SURFACE

Abstract

The purpose of this study is to determine whether piston friction can be reduced by applying a micro-pattern to the skirt portion of the piston, which accounts for the largest proportion of engine parts. The roughness of the ready-made pistons was reduced before etching the micro-scale pattern onto the piston skirt. The micro-patterns were screen-printed on the piston skirt, and kept uniform through etching. The friction reduction effect of the piston was confirmed through an engine experiment using a 1.6 L four-cylinder gasoline engine to remove parts. A hexagonal shape that is representative of bionic textures was selected for the micro-pattern, and circular and cross-hatch patterns were additionally produced for comparison. The friction experiments with the patterning pistons confirmed that friction was reduced by up to 6.74 % by adjusting the spacing of the hexagonal pattern. It was also confirmed that friction was reduced in the cross-hatch pattern by up to 5.28 %. The friction reduction effect may vary depending on the parameters used for a specific pattern.