Lubricants and technical fluids

Lubricants and technical fluids are used to carry out the working functions of machines and machines. They provide reliability and efficiency of operation of various equipment.

Types of lubricants

In the process of operation of the mechanisms, the contacting surfaces move and their wear and tear with heat release as a result of friction. To reduce it, mineral and synthetic lubricants are used.

Lubricants and technical fluids mostly contain products as a basis:

• Distillate - vacuum distillation of fuel oil (light fractions);
• Residual - obtained by dispersing tar.

This or that type of mineral oil is obtained by mixing distillate and residual components in certain proportions and adding additives to them.

Synthetic oils are produced by the synthesis of certain hydrocarbons with the addition of additives, which improve the operating conditions.

Types of lubricants

• Motor;
• Transmission;
• Hydraulic;
• Greases.

Additives for lubricants

The requirements for oils operating under different conditions are constantly tightened. The base base is not able to fully provide the necessary properties, which can be created only by adding additives in oils and technical fluids. Their number ranges from a fraction of a percent to 15% or more.

Additive types:

• Single - functional - provide one of the properties: anti-wear, extreme pressure, viscosity, antioxidant, antifriction, antifoam, depressor, detergent-dispersant, etc .;
• Multifunctional - highly effective polymeric compounds, giving the oil several performance characteristics;
• Additive packages and compositions - mixed and chemically related additives, improving properties and creating a new quality (up to 15 components).

Properties of oils and technical liquids

For products such as lubricant and working fluid, technical conditions or GOST, a set of various characteristics determine the conditions for their use.

1. Lubricating ability - a combination of antifriction, antiwear and extreme pressure properties. The main indicator is the viscosity characterizing the resistance to flow between the layers of the fluid (dynamic viscosity, Pa ∙ s). Another characteristic is the kinematic viscosity, which is determined from the rate of flow of the liquid under its own weight through the capillary of the viscometer. It is measured in m ² / s. For oils, the dependence of viscosity change on temperature is particularly important. It is estimated through the viscosity index.
2. Thermooxidation stability is an indicator of the antioxidant properties of the oil, characterized by the time of transformation of a thin oil layer into a lacquer film. The higher it is, the better the product. The process of oxidation begins when heated to 50-60 ^o C. Intensity increases significantly, starting from 250 ^o C. At the same time, the oil darkens and its physicochemical properties change.
3. The detergent-dispersing properties of motor oil reflect its ability to reduce the formation of deposits and carbon deposits within the engine and to maintain contaminated products in a suspended state.
4. The anticorrosion properties of the oils gradually deteriorate with the accumulation of wear products. Corrosivity is estimated by the acid number determined by the amount of mg KOH required to neutralize acids in 1 g of oil. The maintenance of acids at its operation increases in 3-5 times and they are most dangerous for details. The properties of oils are improved by the introduction of additives forming protective films on the metal surface or neutralizing acids with alkaline earth metals.

Engine oils

Reciprocating internal combustion engines (ICE) are particularly in need of lubrication. For them, motor oils are used, the properties of which are selected specifically for each equipment.

For a long time, the ICE used pure mineral oil. Modern forced engines required the introduction of additives. Mostly all-season oils are used, with the satisfaction of viscosity requirements over a wide temperature range.

For many aggregates, semi-synthetic - mineral water with the addition of synthetic organic components is suitable. Buying it, you need to pay attention to the authenticity and quality of the product. Most follow the recommendations of the instructions for this car. Here you need to know that manufacturers recommend the brands of oils from which they make a profit. Those who are not too versed in the brand of products, you need to follow their advice.

Classification of motor oils

According to their performance, engine oils are classified into groups for engines:

• A - unbuffered carburettor (few additives).
• B - low-pulsed (3-5% additives).
• B - medium-weighted (up to 8% additives).
• D - high-fired (8-12% multifunctional additives).
• D - high-weight heavily loaded diesel engines (18-25% additives).

According to the degree of viscosity, motor oils form 7 classes: 6, 8, 10, 12, 14, 16, 20. All-weathers are made from mineral motor oils by thickening the base with low viscosity with macropolymer additives. There are 10 classes, each of which is represented as a fraction, for example, 4s / 8. The numerator indicates the viscosity class at -18 ° C, and in the denominator - at 100 ° C.

If the engine oil grade is known, for example M-6 _s / 10 V ₂ , it can be deciphered as follows: M - motor, 6 _s - viscosity class with thickening additive, 10 - viscosity at 100 ⁰ C, B - medium-engine, 2 - for diesels .

The quality of the engine oil is checked at the diagnostic center, which requires certain costs. There is a simple way of checking: from the probe, you need to put a drop of oil on the surface of the newspaper. If it quickly fades, leaving a few fat circles on the surface, this indicates a quality product.

High stability of the drop characterizes the loss of useful properties. Such control is suitable for evaluating the quality of fresh lubricant.

Transmission oils

The transmission consists of gears and distributions, bridges, steering transmission, etc. Lubrication is necessary for gears of different types. Transmission oils are produced from a mineral or semi-synthetic base with functional additives based on chlorine, phosphorus, sulfur and disulfide, creating a protective film that protects the parts from negative effects. Viscosity of the agent should preserve the film at a high load and temperature. In the cold season, the viscosity of the oil should not interfere with the operation of the mechanisms, for which a composition suitable for the viscosity index is selected.

Functions of gear oils:

• Reduction of friction and wear;
• Heat removal from contact zones;
• Reduction of shock loads;
• Not toxicity and wastelessness.

The most affordable for technical fluids and lubricants on a mineral basis. They have good characteristics, creating a reliable protective film.

Synthetic oils are much higher in quality, but they are the most expensive products. A good value for money is semi-synthetic.

Domestic gear oils are in viscosity grade 4. According to their operational properties, they are divided into 5 groups. In the marking of different compositions indicate the main characteristics, for example, TM-5-9 _z - transmission oil of the 5-th group, viscosity of the 9th class with a thickening additive. An example of a foreign classification is SAE 80W-90, where the marking designates: 80 - viscosity class, W - winter, 90 - corresponds to minimum viscosity 14 mm ² / s at 99 ⁰ С.

Fluids for hydraulic systems

In the systems of hydromechanisms and drives, special technical fluids are used to drive them. They are required to:

• Good pumpability and low viscosity versus temperature;
• High anticorrosive properties and absence of swelling or destruction of hydraulic seals;
• High lubricity;
• Chemical and physical stability with preservation of initial properties for a long time in the process of operation;
• Absence of impurities, water and corrosive substances that cause corrosion.

Hydraulic oils include about 20 titles. They are made by mixing petroleum distillates with additives. The most frequently used spindle oil is AU. Oil is known for MG-30, M-2IMP, AMG-10, MGE-10A.

Fluids for shock absorbers and brake systems

Brake technical fluids are designed for operation in hydraulic systems of machines. They are required to:

• Low freezing temperature;
• Low viscosity;
• Good lubricity;
• Anticorrosion resistance;
• No damaging effect on rubber seals.

Types of brake fluids.

1. ESC - 60% castor oil + 40% ethyl alcohol.
2. BSK - 50% castor oil + 50% butyl alcohol.
3. 35% glycerin + 65% alcohol.
4. "Neva" and GTZH-22M - based on glycol with additives.
5. "Tom" - a mixture of glycols with esters of boric acid.

Brake technical fluids on a castor base at a temperature below -20 ⁰ C freeze, and in the solution there is only alcohol. In this regard, they are selected depending on the region. The replacement of technical fluids in winter and summer time is rare. Most prefer to use the all-season liquid, which is a composition on a glycol basis. The best of them is "Tom", which has good anti-corrosion and anti-wear properties.

For shock absorbers, the compositions AZ-12T and MGP-10, which are a mixture of mineral oil of low viscosity with silicone fluid and additives, are used.

Technical Coolants

The liquid cooling system is designed to maintain the required temperature of the engine. It is closed, taking away heat from the working mechanisms and passing it through the radiator to the environment.

Previously, power plants were cooled by water, but it had to be abandoned because of the small thresholds of freezing and boiling. In addition, it forms a scum and is a source of corrosion of metal.

In the future, technical cooling fluids changed in composition, but the basis was water.

The greatest use of antifreeze - a mixture of water with glycols and special additives. They have the following advantages:

• Low freezing temperature;
• Small expansion when freezing;
• The boiling point is above 110 ° C;
• Good lubricating properties.

Antifreeze based on cheap ethylene glycol is a toxic technical fluid. Less toxic substances are based on propylene glycol, but their cost is much higher.

Conclusion

Oils and technical fluids are on the market in a wide range. The car enthusiast without experience of their application should be guided by the compositions recommended by the instruction to a certain brand of the car. Particular attention should be given to the winter period of operation. When storing a car in a heated garage, all-weather liquids are quite suitable. It is important to focus on quality indicators, not prices. In addition, it is necessary to take into account other factors, in particular, the life of the engine.