How many kinds of engine oil additives are there? What are they?




Commonly used automotive engine oil additives mainly include detergents, dispersants, antiwear agents, antioxidants, anticorrosives, viscosity modifiers, pour point depressants, rust inhibitors and antifoaming agents.

1. Clean dispersant, carbon particles generated by fuel combustion, soot and dust in the air will enter the engine oil, produce acidic substances in the environment of high-temperature oxidation of the engine oil, and finally form carbon deposits, colloids, and acidic substances block the oil circuit and cause lubrication failure. The cleaning dispersant is to clean the carbon deposit on the surface of the machine through solubilization, dispersion, acid neutralization and washing. Disperse and suspend them in the oil and remove them through a filter. His usage accounts for 50% of all additives.
2. Antioxidant and anticorrosive agent. Re-refined engine oil cannot avoid contact with air and corrosion of metals by oxides, so it is necessary to add antioxidants.
Third, viscosity index improver. Improve the viscosity-temperature performance of lubricating oil, also called multi-grade engine oil, which can be used throughout the year in different seasons.
Fourth, pour point depressant. Through the eutectic and adsorption of the alkyl side chains on the molecule and the solid hydrocarbon molecules in the oil, the growth direction and crystal shape of the wax are changed to form uniform and loose crystal grains to prevent the formation of a three-dimensional network structure that causes the solidification of the oil, and reduce the condensation of the oil. Point to improve low temperature fluidity.
5. Anti-foaming agent. When the crankcase is running at high speed, foam will be formed under the action of strong vibration and stirring, which will increase the contact surface between oil and air, which will cause oxidation, shorten the service life, reduce the cooling effect, cause overheating or even burnout of parts, and increase wear Anti-foaming agents prevent the formation of foam.
6. Oiliness agent, anti-wear agent and extreme pressure agent. It is difficult to ensure liquid lubrication between the engine piston and the cylinder wall, and it often works under harsh boundary lubrication conditions. In order to reduce wear, these three additives are usually added to improve the oiliness and extreme pressure performance of the oil. Oily agent refers to additives that form physical or chemical adsorption films on the metal surface to reduce friction and enhance lubrication under boundary lubrication conditions. Also called friction modifiers, there are animal and vegetable oils, fatty acids, fatty acid esters and sulfurized greases. Extreme pressure agent refers to boundary lubrication under high temperature and high pressure. It is customary to call this most demanding boundary lubrication extreme pressure lubrication. The additive can form a chemical reaction film on the metal surface to prevent the formation of local sintering on the friction surface. The compound mainly contains active elements such as sulfur, phosphorus, and chlorine. It decomposes and reacts with the friction surface of the metal at high temperature of friction, generating shear stress and melting point Compounds that are lower than metals flow to the surface around the contact point during the formation process, making the surface smooth and smooth, playing the role of chemical polishing, and reducing the load per unit area.
7. Anti-rust agent. It is an oil-soluble surfactant that can protect metal surfaces and delay corrosion in three ways. a. Form an absorbent protective film on the metal surface. b. Replace the water film and water droplets on the metal surface, remove the water on the metal surface, sc, collect in oil, disperse polar substances such as water and organic acids in the oil, and encapsulate them in micelles and micelles.
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