What is the role of lubricating oil?

Release time: 2024-03-21

The amount of petroleum lubricating oil accounts for more than 90% of the total amount, so lubricating oil often refers to petroleum lubricating oil. It is mainly used to reduce the friction between the surfaces of moving parts, and at the same time has the functions of cooling, sealing, anti-corrosion, anti-rust, insulation, power transmission, and cleaning impurities. The feed is mainly a lube oil fraction and a residue fraction from a crude oil distillation unit. The most important properties of lubricating oil are viscosity, oxidation stability and lubricity, which are closely related to the composition of lubricating oil fractions. Viscosity is an important quality index to reflect the fluidity of lubricating oil. Different conditions of use have different viscosity requirements. Heavy load and low speed machinery to choose high viscosity lubricating oil. Oxidation stability indicates the antioxidant capacity of oil in the use environment due to temperature, oxygen in the air and metal catalysis. After the oil oxidation, according to the use conditions will generate fine asphaltene-based carbon-like substances, a viscous lacquer-like substance or film, or viscous water-containing substances, thereby reducing or losing its use performance. Lubricity represents the wear-reducing performance of the lubricating oil. The concept of lubricant additives is to add one or more compounds to the lubricant to obtain some new characteristics or to improve some of the existing characteristics of the lubricant. Additives are mainly antioxidants and metal deactivators, extreme pressure anti-wear agents, friction improvers (also known as oil-based agents), clean dispersants, foam inhibitors, rust inhibitors, anti-oxygen preservatives, flow point improvers, viscosity index improvers, anti-emulsion and other types. The additives sold in the market are generally composite products of the above single additives. The difference is that the composition of the single additive is different and the proportion of several single additives within the composite additive is different.

　　Lubrication:

When the engine is running, if some friction parts 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 (this is the main reason for many leaking or leaking cars to pull cylinders and hold shafts). Therefore, it is necessary to give good lubrication to the friction parts in the engine. When the lubricating oil flows to the friction part, it will adhere to the friction surface to form an oil film, reducing the resistance between the friction parts, and the strength and toughness of the oil film is the key to its lubrication. However, the amount cannot be too large, because the amount is too large, it will produce the resistance of the square relationship, which has a great impact on the speed, so special attention should be paid to the amount.

　Cooling:

Only a small part of the heat generated after the fuel is burned in the engine is used for power output, friction resistance consumption and driving of auxiliary mechanisms; most of the rest of the heat is discharged into the atmosphere with the exhaust gas, and will also be taken away by the cooling medium in the engine Part. The 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 done by the engine cooling system, and on the other hand, the lubricating oil absorbs heat from the surfaces of the cylinder, piston, crankshaft, etc. and then takes it to the oil pan for dissipation.

　　Washing:

When the engine is working, it will produce a lot of dirt. Such as the sand and dust brought by the inhalation of air, the carbon deposits formed after the combustion of the mixed gas, the jelly generated after the oxidation of the lubricating oil, the friction between the parts to produce metal chips, and so on. These dirt will adhere to the friction surface of the machine parts, if not cleaned, it will increase the wear of the machine parts. In addition, a large amount of glue will cause the piston ring to stick, causing the engine to not run normally. Therefore, these dirt must be cleaned in time, and this cleaning process is completed by circulating lubricating oil in the body.

　　Sealing:

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, which can ensure that the motion pairs will not be stuck. However, these gaps can cause poor cylinder sealing, and the result of combustion chamber air leakage is to reduce 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 exhaust gas from escaping down into the crankcase.

　　Rust Prevention:

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

　　Eliminate shock loads:

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

■

Advantages and Application of Metal Processing Cutting Fluid

2024-03-21