The Influence of Oil Pressure in the Engine Lubrication System on Friction Losses

Abstract

The purpose of the internal combustion engine lubrication system is to provide optimal conditions for the oil film formation in all friction couples, such as a piston-cylinder, piston rings-cylinder, main bearings, etc. The oil film is designed to minimize the wear of the elements while ensuring the smallest possible friction losses. Lack of continuity of the oil film, and thus boundary or mixed friction conditions, obviously have a negative effect on the friction losses. However, the continuous oil film, depending on the conditions of its formation, may be characterized by different values of friction losses. One of the factors that may affect the conditions of formation of the oil film is the value of oil pressure in the lubrication system. In the paper the results of researches on friction losses carried out on an engine test bench are presented. The study consisted of measuring the driving torque of the internal combustion engine by an electric machine which is the source of power for the internal combustion engine. The oil temperature, the oil pressure, which was generated by independent from the engine oil pump, and the rotational speed of the crankshaft were the variables during test stand measurement. The article analyzes the results and conclusions are drawn.