Engine oil, gasoline, lubricating oil

Engine oil, that is, engine lubricant, English name: Engine oil. The density is about 0.91×10³ (kg/m³), which can lubricate and reduce wear, assist cooling and cooling, seal and leak prevention, rust and corrosion prevention, shock absorption and cushioning for the engine. It is known as the "blood" of automobiles. Engine oil is made up of two parts: base oil and additives. Base oil is the main component of lubricating oil, which determines the basic properties of lubricating oil, and additives can make up for and improve the shortcomings of base oil performance, give some new properties, and are an important part of lubricating oil.

The engine is the heart of the car, and there are many metal surfaces in the engine that rub against each other, and these parts move fast and in poor environments, and the operating temperature can reach 400°C to 600°C. The new technology transforms natural gas into crystal-pure, fully synthetic base oils, which are supplemented with unique powered cleaning technology to create lubricants with superior cleaning protection. Under such harsh working conditions, only qualified lubricating oil can reduce the wear of engine parts and prolong the service life. The engine oil on the market can be divided into two types: mineral oil and synthetic oil due to its different base oils (vegetable oil is not counted due to the scarcity of production). Synthetic oil is divided into: fully synthetic and semi-synthetic. Lubricating oil base oils are mainly divided into two categories: mineral base oils and synthetic base oils. Mineral base oils are used in a wide range of applications in large quantities (about 95% or more), but some applications require the use of synthetic base stock blends.

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As a kind of machinery, the engine has its common requirements for lubricating oil compared with general machinery, such as appropriate viscosity, certain performance requirements such as oxidation, anti-wear, anti-corrosion and viscosity temperature. However, the engine is a special kind of machinery, and its requirements for lubricating oil have its special side, and its particularity mainly includes:
1) The overall requirements for the engine are small size, light weight, compact mechanism, and large output power, so it bears a large load on the unit friction surface.
2) In addition to the friction heat, it is also affected by the heat of combustion, so the temperature of the friction surface is very high, which reduces the viscosity of the lubricating oil and makes it difficult to form the oil film.
3) The combustion gas of high temperature and high pressure in the combustion chamber will leak to the crankcase through the gap between the piston, the piston ring and the cylinder liner, and these combustion gases are the gases and some particulate matter (soot) produced by the complete and incomplete combustion of fuel and a small amount of lubricating oil, which usually become the main component of the crankcase blow-by, which will pollute the lubricating oil and promote its oxidation under certain conditions.
4) The lubricating oil required around the combustion chamber enters through the gap between the piston and the cylinder liner, and the gap between the valve stem and the valve guide, so it is difficult to supply oil.
5) The piston and valve and other parts reciprocate during work, so the relative velocity at the upper and lower dead center is zero, which makes it difficult to form the oil film. The piston pin and bushing are in oscillating motion, and the oil film is difficult to form.
6) When the engine is parked and runs for a long time, the temperature difference is very large, and due to the thermal expansion and thermal deformation of the parts, it is difficult to control the gap of some friction pairs, which may cause adhesion and sintering due to too small gap, or damage caused by impact and vibration due to too large gap. In these cases, the oil film is difficult to adhere.
7) There are a variety of friction pairs in the engine, such as pistons and cylinder liners, crankshaft journals and bearings, cams and followers, gears, etc., although they have different requirements for the lubricating performance of lubricating oil, but only one kind of lubricating oil can be used in an engine (except for large marine diesel engines), so a variety of lubrication states should be taken care of when selecting lubricating oil.
8) The use environment of the vehicle engine is complex, such as temperature, humidity, atmospheric pressure, dust, etc. At the same time, because engine oil often contains sulfur, lead and other elements, it will promote the corrosion and wear of certain parts.