Automotive technology cannot work without fuel, lubricants and other materials. They have a number of special characteristics that depend on the characteristics of the system. Operational materials correspond to the model of automotive equipment, perform many functions in the process of application. What they are, how they differ, will be discussed later.
General definition
Operating materials are various materials used in automobiles, such as gasoline, diesel fuel or gas. These are expensive and environmentally unsafe compounds, for which scientists are now looking for alternatives. Instead of natural resources, electricity is involved in the process. For modern materials that are used in the operation of the car, put forward high demands. This is required to improve environmental safety.
All over the world, the classic types of operational materials remain the most demanded. As energy for the movement of a vehicle, gasoline is used, as well as other similar substances of natural origin. But all this has a bad effect on the environment.
Operational materials support the car system in the required form. For this, each model involves the use of its own kind of fuel and other compounds. For this, a system of special markings is used. Different vehicles have different structures. Therefore, universal materials cannot be.
Varieties
There are three groups of materials that are used in automobiles:
- Combustible.
- Lubricating compounds.
- Technical fluids.
The fuel may be liquid or gaseous. In the first case, it is gasoline and diesel. They convert chemical energy into mechanical energy through an internal combustion engine. Gasoline is used in piston engines with spark ignition, and diesel fuel is ignited by compression.
Oils used in automobile systems are used to save energy that is spent on friction. At the same time, lubricating products ensure the safe operation of the vehicle. Depending on the application of the oil, there are:
- motor;
- transmission;
- turbine;
- cylinder;
- compression;
- gearboxes;
- electrical insulating;
- conservation;
- vacuum;
- specialized;
- instrumentation.
In a separate category, plastic greases are allocated, with the help of which sealing, sealing, preservation, etc. are performed.
Special technical fluids can perform different functions. They can be used in hydraulics as a working fluid, as a coolant, etc.
Petrol
Considering the operational characteristics of materials, it is worth starting with the most common type of fuel - gasoline. This is a refined product, which, along with diesel fuel, is a mixture of hydrocarbons, various additional additives that improve the operational properties of the fuel.
The composition of gasoline included hydrocarbons that are capable of boiling off when heated to 35-200 º. In diesel types of fuel, these components boil away at 180-360 º. Today, they put forward stringent operational requirements for materials, including gasoline:
- uninterrupted supply to the engine;
- the formation of a mixture with air in the right proportion;
- normal combustion, without detonation, complete inside the engine;
- at different temperatures contributes to a quick, reliable starting of the motor;
- does not cause corrosion and premature wear;
- minimum amount of deposits in the system;
- during storage and transportation the original qualities are preserved.
Gasoline properties
To fulfill these requirements, gasolines must have a number of properties. The most important of them are:
- Carburetion properties. Gasoline should form a fuel mixture with air, which should be uniform and completely burn out in the engine. For this, gasoline must have certain indicators of density, volatility, viscosity, saturated vapor pressure, low temperature properties.
- Combustion. This is the speed of the reaction of the interaction of hydrocarbons and oxygen, which is accompanied by a large amount of heat generated.
- Normal and detonation combustion. In a normal process, the process is characterized by complete combustion of the fuel, its oxidation. The flame propagation velocity in this case is 10–40 m / s. With detonation combustion, the speed increases to 1500-2000 m / s. In this case, the process is uneven, a shock wave occurs.
- Antiknock. The composition includes tetraethyl lead, which is mixed with substances that prevent deposition of lead oxides. They are called scavengers.
Diesel fuel
Considering the main operational materials, it is worth mentioning such a variety as diesel fuel. Due to certain features, this type of engine is 25-30% more economical than gasoline varieties. In most cases, diesel fuel is used for engines of buses, trucks, as well as on some cars.
To diesel put forward certain requirements during operation:
- Uninterrupted entry into the system.
- Promoting a good mix.
- Should not cause corrosive wear.
- In the exhaust, inlet tract, combustion chamber, no deposits should remain on the sprayer needle.
- The original characteristics should be preserved during transportation, storage.
The most important qualities of diesel fuel are its volatility, flammability, as well as work at lower temperatures.
In the process of using operational materials, it is required to ensure a good start of the motor under any conditions. Therefore, the fraction cannot be light. Severe varieties have better self-ignition. This diesel fuel capacity is estimated by the cetane number (CC). This is a conditional characteristic, which is equal to the percentage of cetane in the reference mixture. It should be equivalent to the test fuel in terms of flammability.
The self-igniting factor affects the tendency of diesel fuel to form deposits, engine operation and easy starting. In modern vehicles, a composition is used that is characterized by a CC from 45 to 50 units. If the fuel has this indicator at the level of 40 units, the engine will work hard. An increase in CC above 50 units is impractical. The fuel will burn faster than it can spread through the chamber. Because of this, the process of the motor is disrupted. Such diesel fuel will not be able to burn completely. Smoke will be observed, and the efficiency of the motor is markedly reduced.
Gaseous fuel
Automotive consumables also include gaseous fuels. According to their physical condition, they are divided into two categories:
If hydrocarbons are characterized by critical temperatures below the usual level, then the gas is used in compressed form. If the indicator is higher, then the compositions are used in a liquefied state. The main requirements for gaseous fuels are:
- good mixture formation;
- high calorific value;
- should not lead to corrosion wear;
- minimum amount of deposits in the system;
- preservation of properties during storage and transportation;
- low cost of manufacture and transportation.
Propane or butane is used to produce liquefied gas. They are easily converted to a liquid state. For their designation, the CIS marking is used. Such materials are stored under a pressure of 1.6 MPa. For cars, mixtures of propane and butane are produced, which can be used in summer or winter.
The composition of the CIS add odorants, which give the mixture a strong odor. This allows leak detection.
Automotive consumables also include compressed gases. Their main components are methane, carbon monoxide, and hydrogen. They are obtained from gases of various origins. In the labeling, such formulations have the letters LNG. Methane in such a mixture contains from 40 to 82%. Without cooling, this gas cannot be brought into a liquid state.
When using LNG fuel, it turns out to significantly reduce the carrying capacity of the vehicle. The mileage of the car at a full gas station in this case will be 2 times less than on gasoline. Since methane has a high detonation resistance, engines boost in compression ratio. LNG is safer than gasoline in terms of flammability. But at the same time, starting the engine at low temperatures is difficult.
Motor oils
In a separate category are the operational lubricants. One of their varieties is motor oil. They provide:
- reduced wear of moving elements due to friction due to the creation of a strong and thin oil film on the surface;
- sealing gaps at joints;
- heat removal from moving parts;
- removal of wear products, contaminants from friction zones;
- protection of metal elements from corrosion;
- preventing the formation of deposits of any kind.
Engine oils today have advanced requirements:
- optimal viscosity in all operating modes;
- good lubricating qualities;
- low rate of evaporation, delamination and foaming;
- corrosion protection, low oxidation of the lubricant;
- low oil consumption during engine operation;
- long term of operation without damage to the system;
- preservation of qualities during storage and transportation.
The main qualities of the oil are viscosity and resistance to low temperatures. Today, three groups of motor oils are used:
- synthetics (completely from artificial components);
- mineral composition (produced during oil refining);
- semisynthetics (mineral and synthetic compounds are present).
There are certain norms for the consumption of operational materials, which depend on many factors. It is worth noting that in synthetic varieties of lubricants, this figure is higher. The rate of burning will be 30-40% higher than that of mineral compounds. Therefore, synthetic oils change much less frequently. These are more advanced compounds that can provide high-quality protection of components and mechanisms even under loaded conditions.
Synthetic oils have better viscosity-temperature characteristics, due to which the fuel consumption of the machine is reduced by 4-5%. But it is worth noting that synthetics are not suitable for all motors. For engines of a new type, this is the best option. But for engines with mileage, which were installed on cars in the past, only mineral grease is suitable. Wrong choice of type of composition leads to the rapid destruction of mechanisms.
Gear oils
Today there is a huge variety of maintenance materials used in automobile systems and other units. One of the varieties of lubricants is gear oil. It is used to improve the quality of gears. Such mechanisms are used in transmission of various types. Most often in modern cars used hypoid (screw) transmission. They have stronger teeth compared to straight teeth. This ensures smooth, silent operation of the mechanism.
In order for the system to work smoothly, increased requirements are put forward for oils for such gears. This is due to high sliding speeds. Transmission oils perform a number of functions in the system:
- reduce mechanical wear of moving elements;
- reduce friction energy loss;
- contribute to the removal of heat from rubbing pairs;
- reduce noise, vibration of gears;
- provide protection against shock loads;
- prevent the development of corrosion;
- in hydromechanical transmissions perform the function of a working fluid.
The operational properties of materials also put forward increased requirements. Depending on the conditions in which the lubricant operates, the quality of the material is determined. The main parameters affecting the operation of the oil in the transmission are:
- temperature condition;
- gear rotation frequency;
- specific pressure in the contact zone.
Transmission oil is subject to significant heat. Initially, it has an ambient temperature. Then, during operation, the heating level reaches 120-130 º. In some cases, the indicator can increase to 150 º. Therefore, the grease must be resistant to high temperature heating. In frost, the grease does not freeze, and when heated, it should not become excessively fluid.
Grease
There are some requirements to the quality of service materials. Many formulations are being developed that can provide the correct working conditions for the equipment. One of the commonly used substances in the car system is grease. It has a thick consistency similar to ointment. Such a product consists of an oil base and a solid thickener.
The grease should have high conservation, antiwear properties, chemical stability, and heat resistance. For this, special additives are present in the composition. Greases can be:
- anti-friction;
- conservation;
- cable cars;
- sealing.
Considering the operational properties of materials, it is worth noting that each of the listed varieties has its own field of application. So, antifriction compounds are used to reduce wear and friction of movable mechanisms. Preservation varieties prevent the development of corrosion during storage, operation. In the respective nodes, rope and sealing compounds are used.
Cushioning liquids
Technical fluids include various operating materials. One of the varieties is a composition intended for damping systems of body vibrations. These are shock-absorbing liquids that are used in telescopic shock absorbers. This allows you to make the car smoother when driving on a bad road.
Low viscosity fluids serve as a working fluid in the system. They are made mainly on an oil basis. The main indicator that is used to determine the properties of a shock-absorbing fluid is its viscosity. Particularly high demands are made on this characteristic at subzero temperatures. Otherwise, the shock absorbers work noticeably worse. The suspension may be blocked due to this. Therefore, today synthetic formulations are used.
The shock-absorbing fluid should have the appropriate indicators of thermal conductivity, heat capacity, high lubricating properties. It should not be prone to foaming, oxidation. Important qualities are mechanical stability, an indicator of evaporation, compatibility with structural elements, especially with rubber seals.