EVALUATION OF MOTOR OIL PERFORMANCE PROPERTIES BY THERMAL OXIDATION STABILITY

Abstract

The article presents the results of a research on the thermal oxidation stability of motor oils as one of the key indicators of their operational reliability and durability. The physical and chemical properties of motor oils that affect their resistance to oxidation processes under the influence of high temperatures and mechanical stress that occur during the operation of a car engine are considered. The article analyzes the consequences of the engine oil oxidation process that occurs during engine operation, namely the formation of various acids, varnishes, sludges and other undesirable products that adversely affect engine performance. To determine the thermal-oxidative stability of motor oils, a specialized device was used that simulates oxidation processes in the working areas of parts during the operation of oils in car engines. For the research, a synthetic motor oil of viscosity class SAE 5W40, brand ZIC SK X9, was selected. The experimental brand of engine oil was used in gasoline engines of Renault Logan passenger cars. The engine oils were studied and their thermal oxidation stability was determined. During the experimental research, the coefficient of thermal oxidation stability and the coefficient of evaporation of engine oil were determined. Based on the results obtained, a graphical dependence of the change in the coefficient of thermal oxidation stability of ZIC SK X9 engine oil on the mileage of the car was constructed. The results of the experimental studies make it possible to establish criteria for selecting engine oils for different operating conditions of passenger cars, as well as to develop recommendations for increasing their thermal stability, improving their performance properties and, accordingly, extending their service life. The obtained experimental data are of practical importance for manufacturers of lubricants and consumers interested in improving the reliability of internal combustion engines and reducing the consumption of lubricants during the operation of cars in various conditions.