On the function of lubricating oil in production

  The consumption of petroleum lubricating oil accounts for more than 90% of the total consumption, so lubricating oil often refers to petroleum lubricating oil. It is mainly used to reduce the friction between the surfaces of moving parts. At the same time, it has the functions of cooling, sealing, anti-corrosion, rust prevention, insulation, power transmission, cleaning impurities and so on. It mainly uses lubricating oil and residual oil distillate from crude oil distillation unit as raw materials. The most important properties of lubricating oil are viscosity, oxidation stability and lubricity, which are closely related to the composition of lubricating oil fraction. Viscosity is an important quality index reflecting the fluidity of lubricating oil. Different service conditions have different viscosity requirements. Heavy load and low speed machinery to choose high viscosity lubricating oil. Oxidation stability refers to the oxidation resistance of oil products in use environment due to temperature, oxygen in the air and metal catalysis. After oil oxidation, according to the use conditions will generate fine asphaltene-based carbonaceous substance, viscous lacquer-like substance or film, or viscous water-containing substance, thereby reducing or losing its performance.                 

  Lubricity indicates the wear resistance of lubricating oil. The concept of lubricating oil additive is to add one or several compounds to the lubricant in order to make the lubricant obtain some new properties or improve some existing properties of the lubricant. According to the function of additives, the main types are antioxidant and metal deactivator, extreme pressure anti-wear agent, friction improver (also known as oiliness agent), cleaning dispersant, foam inhibitor, rust inhibitor, antioxidant preservative, flow point improver, viscosity index improver, anti-emulsion and so on. The additives sold in the market are generally the compound of the above single additives, the difference is that the composition of the single additive is different and the proportion of several single additives inside the compound additive is different.

      Lubrication

  When the engine is running, if some parts of the friction are not properly lubricated, dry friction will occur. Practice has proved that the heat generated by dry friction in a short period of time is enough to melt the metal, causing damage to the parts or even stuck (many cars with water leakage or oil leakage appear cylinder, holding shaft failure, the main reason is this). Therefore, it is necessary to give good lubrication to the friction parts of the engine. When the lubricating oil flows to the friction part, it will adhere to the friction surface to form a layer of oil film, reduce the resistance between the friction parts, and the strength and toughness of the oil film is the key to play its lubrication role. But can not use too much, because too much will produce the square relation of resistance, great influence on the speed, so we should pay special attention to the amount.

      Cooling

  Only a small part of the heat generated by the combustion of fuel in the engine is used for power output, friction resistance consumption and drive of auxiliary mechanisms. Much of the rest of the heat is lost to the atmosphere with the exhaust gas and is carried away by the cooling medium in the engine. Excess heat in the engine must be discharged from the body, otherwise the engine will burn out due to excessive temperature. On the one hand, this is accomplished by the engine cooling system, on the other hand, by the lubricating oil from the cylinder, piston, crankshaft surface absorb heat to the oil pan distribution.

      Wash

  When the engine is working, a lot of dirt will be produced. For example, the sand and dust brought by inhalation in the air, the carbon accumulation formed after the combustion of the mixture, the gel generated after the oxidation of lubricating oil, the metal chips generated by friction between the parts and so on. These dirt will adhere to the friction surface of the machine parts, if not cleaned down, it will increase the wear of the machine parts. In addition, a large number of gum will make the piston ring bond stuck, resulting in the engine can not operate normally. Therefore, it is necessary to clean up these dirt in time. This cleaning process is completed by circulating lubricating oil in the body.

      Seal

  There is a certain gap between the cylinder and the piston, the piston ring and the ring groove, and the valve and the valve seat of the engine, so as to ensure that the movement between the pair will not stick. But these gaps can cause poor cylinder seal, combustion chamber leakage results in reduced cylinder pressure and engine output power. The oil film formed by the lubricating oil in these gaps ensures the sealing of the cylinder, maintains the cylinder pressure and engine output power, and prevents the exhaust gas from entering the crankcase downward.

      Rust prevention

  When the engine is in operation or storage, the atmosphere, lubricating oil, water in the fuel and acid gas produced by combustion will cause corrosion and rust to the parts, thus increasing the damage to the friction surface. The oil film formed by the lubricating oil on the surface of the parts can avoid the direct contact between the parts and water and acid gas to prevent corrosion and rust.

      Shock relief load

  At the end of the compression stroke, the mixture begins to burn and the cylinder pressure rises sharply. At this time, the lubricating oil in the bearing clearance will ease the impact load on the piston, piston pin, connecting rod, crankshaft and other parts of the engine, so that the engine can work smoothly, and prevent direct metal contact, reduce wear.