Learn the basics of engine oil together in winter

Oil has always been a lotcarA vocabulary familiar to users, what exactly is engine oil used for? What do those labels mean? What kind of oil is most suitable for which car? Today, the editor will give you a detailed explanation.

Learn the basics of engine oil together in winter

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●The role of oil

The engine is the heart of the car. There are many metal surfaces in the engine that move in friction with each other. These parts move fast and the environment is poor. The working temperature can reach 400°C to 600°C.Under such harsh conditions, only qualifiedlubricating oilIn order to reduce the wear of engine parts and extend the service life, what requirements should a qualified lubricant meet? In other words, what are the six functions of lubricating oil?

1. Lubrication and wear reduction:pistonAnd the cylinder, the main shaft andBearingThere is rapid relative sliding between them. To prevent the parts from wearing out too quickly, it is necessary to establish an oil film between the two sliding surfaces. The oil film of sufficient thickness separates the surfaces of the relatively sliding parts, so as to achieve the purpose of reducing wear.

2. Cooling down: the oil can bring heat back to the enginetankAnd then spread into the air to helpWater tankCool down the engine.

3. Cleaning and cleaning: Good engine oil can circulate the carbides, sludge, and wear metal particles on engine parts back to the engine oil tank. Through the flow of lubricating oil, the dirt generated on the working surface of the parts is washed.

4. Sealing and leak-proof: the oil can be inPiston ringA sealing ring is formed between the piston and the piston to reduce gas leakage and prevent the entry of external pollutants.

5. Anti-rust and anti-corrosion: Lubricating oil can absorb the surface of the parts to prevent water, air, acidic substances and harmful gases from contacting the parts.

6. Shock absorption and cushioning: When the engine cylinder port pressure rises sharply, the piston, piston chips, connecting rod andCrankshaftThe load on the bearing is very large. This load is transmitted and lubricated by the bearing, so that the impact load on it can buffer.

●Classification of engine oil

Engine oils currently on the market can be simply divided into mineral oils and synthetic oils due to their different base oils (vegetable oils are not counted because of their scarce production). Synthetic oil is further divided into: full and semi-synthetic. Fully synthetic motor oil is the highest grade.

The biggest difference between the two is: synthetic oil uses a wider temperature, longer service life, and higher cost; the same oil film requirements, synthetic oil can be achieved with a lower viscosity, while mineral oil needs to be used compared to synthetic oil. Only thicker viscosity can meet this requirement. In the same working environment, synthetic oil has a much longer lifespan than mineral oil, so the cost is higher, but after comparing the number of oil changes, it is not much higher than mineral oil.

●Marking of engine oil

The viscosity of lubricating oil is usually marked with SAE and other grades. SAE is the abbreviation of "American Society of Automotive Engineers" in English. For example: SAE15W-40, SAE5W-40, "W" means winter (winter), the smaller the number in front of it, the better the low-temperature fluidity of the oil, and the lower the ambient temperature available for use. The better the protection ability of the engine oil; the number behind the "W" (behind a horizontal line) is an indicator of the oil's high temperature resistance. The larger the value, the better the protection performance of the engine oil at high temperatures.

(SAE) Applicable ambient temperature (°C)

5w resistant to external low temperature -30°C

10w resistant to external low temperature -25°C

15w resistant to external low temperature -20°C

20w resistant to external low temperature -15°C

30 Resistance to external high temperature 30°C

40 Resistance to external high temperature 40°C

50 Resistance to external high temperature 50°C

In this way, the applicable external temperature range of 5W-40 engine oil is from -30°C to 40°C; while the applicable external temperature range of 10W-30 engine oil is -25°C to 30°C.

●Classification of engine oil

The series beginning with "S" represent gasoline engine oil, the specifications are: SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM. The series beginning with "C" represent diesel engine oil, the specifications are: CA, CB, CC, CD, CE, CF, CF-2, CF-4, CG-4, CH-4, CI-4. When the two letters "S" and "C" are present at the same time, it means that the oil is a gasoline/diesel universal type.

From "SA" to "SL", the performance of the engine oil will be better than the previous one for each letter increment, and there will be more additives used to protect the engine in the engine oil. The lower the letter, the higher the quality level, and most of the oil levels in international brands are above the SF level. (Tianshan Net)