Changes in the tribological properties of motor, transmission and compressor oils during operating

Abstract

The results of variation of tribological properties of the motor and, transmission and compressor oils, depending on the operating time when operating vehicles. Lubricating (tribological) properties were evaluated using the wear index, which characterizes the effect of antiwear oil additives on the wear of friction surfaces. The wear was determined at a temperature of (20 ± 5) ºC and a constant load of 196N (for motor oils) and 392N (for transmission oils) in flow 1h. The critical load characterizes the limit of the bearing capacity of surfactants in the lubricant material and the ability of the oil to prevent the scuffing of friction surfaces, and the welding  load characterizes the maximum performance of the oil EP additives. When the used engine oil Essolube HT 401 SAE 15W-40 was replaced, its critical load decreased from 1235N to 1098N, it was 11%. The welding load decreased in the car No.1 from 2450N to 2323N, it was 5.2%, in the car No. 2 from 2450N to 2195N, it was 11.4%. There was also an increase in the wear index from 0.39 to 0.59, it was 51.3%. In used engine oil Mobil Delvac MX SAE 15W-40, the critical load reduction from 1098Н to 735Н was 33%, the welding load from 2323Н to 2195Н was 5.5%, the increase in the wear index from 0.29 to 0.39 was 34.5%. Transmission oil XADO Atomic SAE 80W-90 API GL-3/4/5 worked in the rear axle of the car MAN 120 thousand km. The reduction of the critical load from 1166Н to 921Н was 21%, the welding load from 4136Н to 3479Н was 15.9%, the increase in the wear index from 0.33 to 0.5 was 51.5%. When the synthetic compressor oil Planetelf ACD 100 FY is used with a mixture of refrigerants R134a, R142b and R22, the lubricating properties deteriorate progressively, the critical load is reduced by 10.5% and the wear index is increased by 2.8 times per 1 hour of operation in comparison with oil working with refrigerant R 134a. These indicators during the further operation of the air conditioning system will only worsen, this causes a sharp decrease in the lubrication conditions of the air conditioning units and leads to a rapid loss of efficiency and failure of the equipment of the system.