2307 Reduction of Piston Friction Losses in Supercharged Gasoline Engine

This study was aimed at reduction of piston friction losses in supercharged gasoline engine. The floating liner device was improved to measure piston friction forces on supercharged condition. Effects of piston friction forces on skirt clearance, skirt overlap, and skirt roughness were verified from measured results of piston friction forces. As a result, Piston friction losses increased with the increase in engine load, and the increase in fiction losses strongly depended on the amount of overlap in piston skirt. And piston friction losses on high load condition greatly reduced by larger piston skirt clearance and smaller skirt roughness.