Oil has been a familiar word for many car users. What is the use of oil? What do those marks mean? What car is suitable for what oil?
● The role of oil:
The engine is the heart of the car. There are many metal surfaces in the engine that rub against each other. These parts move fast and in poor environment, and the working temperature can reach 400°C to 600°C. Under such bad working conditions, only qualified lubricating oil can reduce the wear of engine parts and prolong the service life, so what requirements should qualified lubricating oil meet? That is to say, what are the six functions of lubricating oil?
1, lubrication and wear reduction: there is a fast relative sliding between the piston and cylinder, spindle and bearing bush, to prevent the wear of parts too fast, it is necessary to establish an oil film between the two sliding surfaces. An oil film of sufficient thickness separates the surfaces of parts that are relatively sliding so as to reduce wear.
2. Cooling and cooling: the oil can bring the heat back to the fuel tank and then send it into the air to help the water tank cool the engine.
3, cleaning cleaning: good oil can engine parts on the carbide, sludge, wear metal particles through the circulation back to the fuel tank, through the flow of lubricating oil, wash the dirty parts on the working surface.
4, sealing and leakage prevention: oil can form a sealing ring between the piston ring and the piston, reduce the leakage of gas and prevent the entry of external pollutants.
5, rust and corrosion prevention: lubricating oil can absorb on the surface of parts to prevent water, air, acid substances and harmful gas contact with parts.
6, shock absorption buffer: when the engine cylinder mouth pressure rises sharply, suddenly aggravates the piston, piston chip, connecting rod and crankshaft bearing load is very large, the load through the bearing transmission lubrication, so that the impact load bearing play a buffer role.
● Classification of oil:
At present, the oil on the market can be simply divided into two kinds of mineral oil and synthetic oil because of the different base oil (vegetable oil is excluded because of the scarce yield). Synthetic oil is divided into: total and semi-synthetic. Synthetic oils are high grade.
The difference is that synthetic oils are used at a wider range of temperatures, last longer and cost more. The same oil film requirements, synthetic oil can be achieved with a lower viscosity, while mineral oil needs a thicker viscosity than synthetic oil to achieve this requirement. Synthetic oils cost more because they last much longer than mineral oils in the same operating environment, but are not much more expensive than mineral oils when compared with the number of oil changes.