1.The main function of lubricating oil
A, lubrication and reduce friction resistance
The function of lubricating oil is to lubricate the various parts of the engine and form an oil film between the two surfaces to reduce the friction resistance and make the operation smoother.
B. Sealing effect
Lubricating oil must be able to form an effective sealing between piston rings and cylinders to prevent leakage of the steam body and contamination of the outside.
C. Cooling effect
In the process of operation, the friction between the machine parts and the parts of the machine produces a large amount of heat or high temperature. The function of lubricating oil is to cool and reduce the temperature of the engine.
D. cleanliness
Remove the harmful impurities and unburned insoluble substances in the machine, and keep these pollutants away from the lubrication surfaces and avoid the formation of sludge.
E. Anti-corrosion function
Lubricating oil, such as oil film that provides contact parts completely separated, will reduce the chance of contact and wear of the machine and prevent corrosion of the metal surface.
2. Grade of lubricating oil
A. The American society of automotive engineers to lubricant viscosity grade rules referred to as "the SAE, have 0 w, 5 w, 10 w, 15 w, w, 20 w, use to multistage oil in cold area, the smaller the number, the better the performance of the low temperature. SAE20, 30, 40, 50, for viscosity grades, it said the number of viscosity of 100 ℃, the greater the number, the greater the viscosity. Such as 15 w40 said the oil at low temperature in line with the requirements of 15 w and accord with the requirement of SAE40 viscosity of 100 ℃.
B. The API is referred to as API for the American petroleum institute. With S level of gasoline engine oil; the later letters, the higher the level: SA SB SC SD SE SF, SG SH SJ diesel engine oil, CD CE CA CB that starts with a C CC CF CF - 4 CG CG, 4 cases of SAE 15 w40 API SG/CD said winter and summer gm north and south of the multistage oil, gasoline, diesel two general performance of the oil.