Investigation of Friction Loss Characteristics of Engine Pistons for Different Engine Operating Conditions

Abstract

In this study, the floating liner method is utilized to measure the friction generated in the piston assembly of a single-cylinder gasoline engine. The piston assembly is subjected to combustion pressure, lubricating friction, and asperity friction during engine operation and reciprocates within the cylinder. Therefore, the main goal of this study is to investigate the effect of engine combustion and lubricant conditions on piston friction. First, we analyze how the combustion pressure, obtained by changing the combustion load and the ignition timing, affects piston friction. Second, by adjusting engine speed and coolant/oil temperature, we analyze how each condition affects piston friction. Through the experiments for each case, it was confirmed that the friction increased as the combustion pressure increased under the same lubrication conditions. It was also confirmed that the piston friction was significantly measured due to the increase in lubrication friction as the engine speed increased. Finally, it was confirmed that as the temperature decreased, the oil viscosity increased, resulting in a large friction loss.