1 overview editor
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(1) [lubricating oil]: oil used as a lubricant (such as petroleum distillate or fatty matter)
Lubricating oil (2) [lubricant]: an oily liquid applied to the surface of a moving part such as a machine bearing or a part of the human body. The utility model has the functions of reducing friction, avoiding heat, preventing machine wear and medical use, etc. Generally, it is the product of fractionated oil, and it is also extracted from plant oil. Also known as "grease". A nonvolatile oil lubricant. According to their sources, there are three categories: animal oil, vegetable oil, petroleum lubricating oil and synthetic lubricating oil. The consumption of petroleum lubricating oil accounts for more than 97% of the total consumption, so it is often referred to as petroleum lubricating oil. It is mainly used to reduce the friction between the surfaces of moving parts, and has the functions of cooling, sealing, anti-corrosion, rust prevention, insulation, power transmission, cleaning impurities, etc. for the machine and equipment. Mainly from the crude oil distillation unit lubricating oil fraction and residual oil fraction as raw materials. The main 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 use 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 in service environment due to temperature, oxygen in air and metal catalysis. After the oil is oxidized, according to the service conditions, it will generate fine asphaltene based carbon like substances, which are viscous paint like substances or paint films, or viscous aqueous substances, so as to reduce or lose its service performance. Lubricity refers to the antifriction performance of lubricating oil. [1]
2 function editing
Lubricating oil is a liquid lubricant used in various types of machinery to reduce friction and protect machinery and processing parts, mainly for lubrication, cooling, rust prevention, cleaning, sealing and buffering. Lubricating oil accounts for 85% of all lubricating materials, with various brands. The annual consumption in the world is about 38 million tons. The general requirements for lubricating oil are:
1. Reduce friction and antiwear, reduce friction resistance to save energy, reduce wear to extend mechanical life and improve economic benefits;
2. For cooling, it is required to discharge the friction heat out of the machine at any time;
3. The sealing shall be leak proof, dust-proof and gas channeling proof.
4. It is anti-corrosion and anti rust, and it is required to protect the friction surface from oil deterioration or external erosion;
5. Clean and wash, and remove the scale on the friction area;
6. Stress dispersing and buffering, load dispersing, shock relieving and shock absorption;
7. Kinetic energy transmission, hydraulic system, remote control motor, friction CVT, etc. Lubrication when the engine is running, if some friction parts are not properly lubricated, there will be dry friction. Practice has proved that the heat generated by dry friction in a short time is enough to make the metal melt, resulting in the damage of the parts or even stuck (this is the main reason why many vehicles with water or oil leakage have cylinder pulling, axle holding and other faults). Therefore, the friction parts in the engine must be well lubricated. 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 play its lubrication role.
8. Lubrication and wear reduction: prevent dry friction of parts, reduce friction resistance and form oil film on the surface of parts.
9. Cooling and cooling: remove heat through circulation of lubricating oil [2] to prevent sintering.
10. Cleaning: wash the metal and other dirt produced by the friction on the working surface of parts through the flow of lubricating oil.
11. Sealing and leak proof: reduce gas leakage and external pollution.
12. Anti rust and anti-corrosion: it can absorb water, air, acid substance and harmful gas on the surface of parts to prevent contact with parts.
13. Shock absorption and buffering: when the pressure at the cylinder port of the engine rises sharply, the load on the piston, piston pin and connecting rod crankshaft bearing is suddenly increased. This load is transmitted and lubricated by the bearing, so that the impact load borne can play a buffering role.
Lubrication effect
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 time is enough to make the metal melt, resulting in the damage of the parts or even stuck (this is the main reason why many vehicles with water or oil leakage have cylinder pulling, axle holding and other faults). Therefore, the friction parts in the engine must be well lubricated. 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 play its lubrication role. But it can not be used too much, because too much will produce the resistance of the square relationship, which has a great impact on the speed, so we should pay special attention to the amount.
Antirust effect
When the engine is running or stored, the moisture in the atmosphere, lubricating oil, fuel oil and the acid gas produced by combustion will cause corrosion and corrosion to the parts, thus increasing the damage of the friction surface. The oil film formed by lubricating oil on the surface of the parts can avoid direct contact between the parts and water and acid gas, and prevent corrosion and corrosion.
Cooling action
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 auxiliary mechanism drive; most of the rest of the heat will be discharged into the atmosphere with the exhaust gas, and will be taken away by the cooling medium in the engine. Excess heat in the engine must be discharged from the engine body, otherwise the engine will burn out due to excessive temperature. On the one hand, it depends on the engine cooling system, on the other hand, it depends on the lubricating oil to absorb heat from the cylinder, piston, crankshaft and other surfaces and then take it to the oil pan for emission.
Washing action
Many dirt will be produced when the engine is working. For example, sand and dust brought by inhalation, carbon deposit formed after combustion of mixture, colloid formed after oxidation of lubricating oil, metal scraps produced by friction between parts, etc. These dirt will adhere to the friction surface of the parts, if not cleaned, it will increase the wear of the parts. In addition, a large amount of gum will make the piston ring stick and stick, which will cause the engine not to run normally. Therefore, it is necessary to clean up these dirt in time. This cleaning process is completed by circulating lubricating oil in the body.
Sealing function
There is a certain clearance between the cylinder and piston, piston ring and ring groove, and between the valve and valve seat of the engine, so as to ensure that there is no stagnation between the moving pairs. However, these gaps can cause poor cylinder sealing. The result of combustion chamber leakage is to reduce cylinder pressure and engine output power. The oil film formed by the lubricating oil in these gaps ensures the tightness of the cylinder, maintains the cylinder pressure and engine output power, and prevents the exhaust gas from flowing down into the crankcase.
Antirust effect
When the engine is running or stored, the moisture in the atmosphere, lubricating oil, fuel oil and the acid gas produced by combustion will cause corrosion and corrosion to the parts, thus increasing the damage of the friction surface. The oil film formed by lubricating oil on the surface of the parts can avoid direct contact between the parts and water and acid gas, and prevent corrosion and corrosion.
Eliminate impact 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, make the engine work stably, prevent the direct contact of metal and reduce the wear. Conclusion 1. Reduce friction and antiwear, reduce friction resistance to save energy, reduce wear to prolong mechanical life and improve economic benefits;
2. For cooling, it is required to discharge the friction heat out of the machine at any time;
3. The sealing shall be leak proof, dust-proof and anti-crosstalk;
4. It is anti-corrosion and anti rust, and it is required to protect the friction surface from oil deterioration or external erosion;
5. Clean and wash, and remove the scale on the friction area;
6. Stress dispersing and buffering, load dispersing, shock relieving and shock absorption;
7. Kinetic energy transmission, hydraulic system, remote control motor, friction CVT, etc.
3 composition editor
Lubricating oil is generally composed of base oil and additives. Base oil is the main component of lubricating oil, which determines the basic properties of lubricating oil. Additives can make up for and improve the performance of base oil, and give some new properties, which is an important part of lubricating oil.
Lube base oil
Lubricating oil base oil mainly includes mineral base oil, synthetic base oil and biological base oil. Mineral base oil is widely used and its consumption is very large (about 95%), but in some applications, the products of synthetic base oil and bio base oil must be used, which makes the two base oils develop rapidly.
Lubricating oil mineral oil base oil is refined from crude oil. The main production processes of lube base oil include atmospheric and vacuum distillation, solvent deasphalting, solvent refining, solvent dewaxing, clay or hydrofining. In 1995, China's current lube base oil standard was revised, mainly modifying the classification method, and adding two kinds of special base oil standards, namely low pour point and deep refining. For the production of mineral lubricating oil, the most important thing is to choose the best crude oil.
The chemical composition of mineral base oil includes high boiling point, high molecular weight hydrocarbon and non hydrocarbon mixture. Its composition is generally alkane (straight chain, branched chain, multi branched chain), cycloalkane (monocyclic, bicyclic, polycyclic), arene (monocyclic, polycyclic arene), cycloalkane arene and non hydrocarbon compounds such as oxygen, nitrogen, sulfur-containing organic compounds and colloid and asphaltene.
Bio base oil (vegetable oil) is becoming more and more popular. It can degrade and reduce environmental pollution rapidly. Because all the industrial enterprises in the world are looking for measures to reduce environmental pollution, and this kind of "natural" lubricating oil has this characteristic. Although the cost of vegetable oil is high, the increased cost is enough to offset the cost of environmental treatment brought by the use of other mineral oil and synthetic lubricating oil.
Additives
Additives are the essence of modern high-grade lubricating oil. Correct selection and reasonable addition can improve its physical and chemical properties, endow new special properties to lubricating oil, or strengthen its original performance to meet higher requirements. According to the quality and performance of lubricating oil, the key to ensure the quality of lubricating oil is to carefully select additives, carefully balance and reasonably allocate them. Commonly used additives are viscosity index improver, pour point drop agent, antioxidant, detergent dispersant, friction reducing agent, oiliness agent, extreme pressure agent, anti foam agent, metal passivator, emulsifier, anticorrosive agent, rust inhibitor, demulsifier, antioxidant and anticorrosive agent.
At present, the main domestic additive producers are in the north, because the water content of additives produced in the north is smaller than that in the south.
Classification according to the nature and processing technology of crude oil
It is divided into paraffin base oil, intermediate base oil and naphthenic base oil.
API classification
API divided the base oil into five categories (api-1509) in 1993, and combined them with eolcs (API engine oil licensing certification system).
test method
category
ASTM
D2007
ASTM
D2270
ASTM d2622 / d4294
/D4927/D3120
category