Fuel quality requirements
When using and storing motor gasoline, the following requirements are imposed.
High energy And thermodynamic characteristics combustion products. When gasoline burns, it should release maximum amount heat, combustion products should have a low molecular weight, low heat capacity and thermal conductivity, a high value of the product of the specific gas constant and the combustion temperature (RT). high value RT is desirable to obtain by increasing T.
Good pumpability. Gasoline must be reliably pumped through the fuel system of vehicles, pipelines, pumps, control systems and other units and communications under any environmental conditions - low and high temperatures, various pressures, dust and humidity.
Optimal evaporation. Under storage and transport conditions, evaporation should be kept to a minimum. When used in an engine, gasoline must have such a volatility to ensure reliable ignition and combustion of fuel with optimal speed in engine combustion chambers.
Minimum corrosivity. Fuels must not contain components that destroy the structural materials of the engine, storage and transportation means.
High stability under storage and application conditions. Fuels for a long time should not change the physico-chemical and operational properties.
Non-toxic. Combustion products must also be non-toxic.
Properties of motor gasolines
Gasoline - fuels that boil away in the temperature range of 28-2150C and are intended for use in engines internal combustion with forced ignition. Depending on the purpose, gasolines are divided into automobile and aviation.
The main indicators of gasoline are knock resistance, saturated vapor pressure, fractional composition, chemical stability, etc. last years environmental quality requirements petroleum fuels limited the content of aromatic hydrocarbons and sulfur compounds in gasoline.
Knock resistance
Detonation occurs if the flame propagation speed in the engine reaches 1500-2500 m/s, instead of the usual 20-30 m/s. As a result sharp drop pressure, a detonation wave occurs, which disrupts the engine's operation, which leads to excessive fuel consumption, a decrease in power, engine overheating, burnout of pistons and exhaust valves.
Octane number (OC)
OC is a conditional indicator that characterizes the resistance of gasoline to detonation and numerically corresponds to the detonation resistance of a model mixture of isooctane and n-heptane.
The OC of isooctane is taken as 100 points, and n-heptane is taken as 0. For motor gasolines (except for A-76), the OC is measured by two methods: motor and research. The octane number is determined by special installations by comparing the combustion characteristics of the tested fuel and the reference mixtures of isooctane with n-heptane. Tests are carried out in two modes: hard (speed crankshaft 900 rpm, intake air temperature 149 0С, variable ignition timing) and soft (600 rpm, intake air temperature 52 0С, ignition timing 13 degrees). Receive respectively motor (CHM) and research OC (OCHI). The difference between the MON and the RON is called sensitivity and characterizes the degree of suitability of gasoline for different conditions engine operation. The arithmetic mean between the OCHM and OCHI is called the octane index and is equated to the road octane number, which is normalized by the standards of some countries (for example, the USA) and is indicated at gas stations as a characteristic of the fuel sold.
In the production of gasolines by mixing fractions of various processes, the so-called blending OCs (OCs) are important, which differ from the calculated values. SPs depend on the nature of the oil product, its content in the mixture, and a number of other factors. For paraffinic hydrocarbons, the NSV is higher than the actual values by 4 points, for aromatic hydrocarbons, the dependence is more complex. The difference can be significant and exceed 20 points. The blending octane number is also important to consider when oxygenates are added to the fuel.
Fractional composition (FS)
The FS of gasoline characterizes the volatility of the fuel, on which the engine start, the distribution of fuel over the engine cylinders, the combustion efficiency, and the engine efficiency depend. Evaporation is determined by the distillation temperature of 10, 50 and 90% (vol.) of gasoline fractions boiling off. The boiling point of 10% gasoline characterizes starting properties. At temperatures below the limit values, vapor locks may form in the engine power system, and at more than high temperatures starting the engine is difficult. In the United States, the starting properties of an engine are characterized by the amount of fuel boiling up to 70 0C. The boiling point of 50% characterizes the speed of the engine's transition from one mode of operation to another and the uniformity of distribution of gasoline fractions over the cylinders. The boiling point of 90% fractions and the end of boiling affect the completeness of fuel combustion and its consumption, as well as carbon formation in the combustion chamber in the engine cylinder. In GOST R 51105-97, which is valid from 01.01.99, the FS of gasoline is determined at a boiling point of 70, 100 and 180 0C.
Saturated Vapor Pressure (VNP)
DNP gives an additional idea of the volatility of gasoline, as well as the possibility of gas plugs in the engine power system. The higher the saturation vapor pressure of gasoline, the higher its volatility. According to the FS of gasoline, the volatility index is calculated.
Gasolines used in summer time, have lower DNP. To ensure the necessary starting properties of commercial gasoline, its composition includes light components: isomerizate, alkylate, butane, fr. n.c. - 62 0С.
Chemical stability (CS)
In the process of storage, transportation and use of gasoline, changes in their chemical composition are possible due to oxidation and polymerization reactions. Oxidation leads to a decrease in the octane number of gasoline and an increase in its tendency to carbon formation. To assess cholesterol, indicators of the content of actual resins, the induction period of oxidation are used.
Active sulfur compounds contained in gasoline cause severe corrosion of the fuel system and transport containers; the completeness of purification of gasoline from these substances is controlled by analysis on a copper plate. Inactive sulfur compounds do not cause corrosion, but the gases formed during their combustion cause rapid abrasive wear of engine parts, reduce power, and worsen the environmental situation.
Among aromatic compounds, the most dangerous for human health and life are benzene and polycyclic ones. Their toxic effect is explained by the possibility of its oxidation in the body. In this regard, in the last normative documents the permissible content of sulfur, benzene and aromatic compounds in gasoline is limited.
Classification of motor gasolines
There are several types of classification of motor gasolines. The main ones (the most commonly used): by volatility, by fractional composition, by the value of the octane number.
Evaporation classification
Depending on the climatic region of application, motor gasolines are divided into five classes (see Table 1.1). Along with determining the distillation temperature at a given volume, it is also possible to determine the volume of evaporated gasoline at a given temperature. The indicator "evapotranspiration index" (EI) has also been introduced. The AI of gasoline characterizes the volatility of gasoline and its tendency to form vapor locks at a certain combination of saturated vapor pressure and the volume of evaporated gasoline at a temperature of 70 0C. AI is calculated by the formula:
where DNP - saturated vapor pressure, kPa; V70 - the volume of evaporated gasoline at a temperature of 70 0C,%.
Classification of motor gasolines by volatility
| Index | Class | ||||
| 1 | 2 | 3 | 4 | 5 | |
| Saturated vapor pressure, kPa | 35-70 | 45-80 | 55-90 | 60-95 | 80-100 |
| Fractional composition: | |||||
| start of boiling, 0 С, not lower | 35 | 35 | not standardized | ||
| 10%, 0 С, not higher | 75 | 70 | 65 | 60 | 55 |
| 50%, 0 С, not higher | 120 | 115 | 110 | 105 | 100 |
| 90%, 0 С, not higher | 190 | 185 | 180 | 170 | 160 |
| end of boiling, 0 С, not higher | 215 | 215 | 215 | 215 | 215 |
| The amount of evaporated gasoline,% (vol.) at 70 0 С | 10-45 | 15-45 | 15-47 | 15-50 | 15-50 |
| Evaporation index, no more | 900 | 1000 | 1100 | 1200 | 1300 |
Classification by fractional composition
Depending on the fractional composition, motor gasolines are divided into winter and summer: for winter, all boiling points are lower than for summer. This greatly simplifies engine starting. low temperatures ah in the case of winter and reduces the risk of vapor locks in the warm season in the case of summer.
Classification by octane number
Depending on the octane number, four brands of gasoline are installed according to the research method: Normal-80, Regular-92, Premium-95 and Super-98 (see Table 1.2). Gasoline "Normal-80" is intended for trucks along with AI-80 gasoline. Gasoline "Regular-92" is intended for the operation of cars instead of leaded A-93. Premium-95 and Super-98 automobile gasolines fully meet European requirements and are competitive in the oil market and are intended mainly for foreign cars operated in Russia.
Classification of motor gasolines by octane number
Research method | Stamps | |||
| "Normal-80" | "Regular-92" | "Premium 95" | "Super 98" | |
| Octane number, not less than: | ||||
| motor method | 76,0 | 83,0 | 85,0 | 88,0 |
| research | 80,0 | 92,0 | 95,0 | 98,0 |
Characteristics of motor gasolines. Norms and requirements for their quality. Medium components of the composition
All gasolines produced in accordance with GOST 2084-77, depending on the volatility indicators, are divided into summer and winter. Winter gasolines are intended for use in the northern and northeastern regions during all seasons and in other regions from October 1 to April 1. Summer - for use in all areas except for the northern and northeastern regions from April 1 to October 1; in the southern regions it is allowed to use summer gasoline during all seasons.
Characteristics of motor gasolines
Indicators | AI-80 | AI-92 | AI-95 |
| Detonation resistance: octane number, not less than: | |||
| motor method | 76 | 85 | 85 |
| research method | 93 | 95 | |
| Mass content of lead, g/dm3, no more | 0,013 | 0,013 | 0,013 |
| Fractional composition: gasoline distillation start temperature, °С, not lower than: | |||
| summer | 35 | 35 | 30 |
| winter | |||
| 10% of gasoline is distilled at a temperature, °С, not higher than: | |||
| summer | 70 | 70 | 75 |
| winter | 55 | 55 | 55 |
| 50% of gasoline is distilled at a temperature, °С, not higher than: | |||
| summer | 115 | 115 | 120 |
| winter | 100 | 100 | 105 |
| 90% of gasoline is distilled at a temperature, °C, not higher than: | |||
| summer | 180 | 180 | 180 |
| winter | 160 | 160 | 160 |
| Gasoline boiling point, °С, not higher: | |||
| summer | 195 | 205 | 205 |
| winter | 185 | 195 | 195 |
| Residue in the flask, %, no more | 1,5 | 1,5 | 1,5 |
| Balance and losses, %, no more | 4 | 4 | 4 |
| Saturated vapor pressure of gasoline, kPa: | |||
| summer, no more | 66,7 | 66,7 | 66,7 |
| winter | 66,7-93,3 | 66,7-93,3 | 66,7-93,3 |
| Acidity, mg KOH/100 cm3, no more | 1 | 0,8 | 2 |
| Induction period at the place of gasoline production, min, not less than | 1200 | 1200 | 900 |
| 0,1 | 0,1 | 0,1 |
Source: GOST 2084 - 77
The parameters of motor gasoline produced in accordance with GOST 2084-77 differ significantly from accepted international standards, especially in terms of environmental requirements. In order to increase the competitiveness of Russian gasolines and bring their quality to the level of European standards, GOST R 51105-97 “Fuels for internal combustion engines. Unleaded gasoline. Specifications”, which comes into effect on January 1, 1999. This standard does not replace GOST 2084-77, which provides for the production of both leaded and unleaded gasolines. In accordance with GOST R 51105-97, only unleaded gasoline will be produced (the maximum lead content is not more than 0.01 g/dm3).
The norms and requirements for the quality of motor gasoline and volatility characteristics in accordance with GOST R 51105-97 are given in the table.
It was said about the basic properties of gasoline and safety precautions when working with it. This article talks about the main classifications of gasoline, the types and methods of its use.
By composition, gasolines are divided into:
- straight-run (obtained by direct distillation of oil);
- cracked gasolines (obtained by processing high-boiling fractions);
- gas (obtained by processing associated gases);
- pyrolysis (obtained as a result of thermal cracking);
- leaded (leaded liquid is added to the finished product, which increases detonation resistance).
Leaded gasoline has not been produced in Russia since 2003.
According to the field of application, gasoline can be divided into:
- automobile;
— aviation;
— gasoline-solvents;
— gasolines as a raw material for the chemical industry (naphtha).
Automobile gasolines produce several brands. The name of gasoline indicates its type ("A" - automobile, "B" - aviation), the method for determining the octane number ("I" - according to the research method), the octane number itself, environmental class according to Euro standards. For example, AI-95-3 stands for motor gasoline with octane rating 95, determined by the research method, complies with the Euro-3 standard. If the octane number is determined by the motor method, then nothing is written after the letter "A": A-76.
Automobile gasolines are produced for winter and summer. For summer, gasoline contains less light fractions, which, by active evaporation, can cause vapor locks that interfere with engine operation.
Aviation gasolines higher octane and higher quality. They must ensure perfect engine operation at any altitude. Aviation gasoline contains a lower amount of light fractions to completely eliminate the risk of vapor lock. Of great importance is chemical stability and a small presence of impurities that cause corrosion of parts and hard-to-remove deposits.
Solvent gasolines used in various areas of production. Extraction gasolines are in great demand, which are used to extract substances such as rosin, vegetable oils, and ozocerite from raw materials.
High-boiling(with a boiling point up to +180 °C) gasoline fractions are used as raw materials in the chemical industry.
Application
— As a fuel, including for internal combustion engines.
- In the chemical industry - raw materials for the production of ethylene, paraffin; in organic synthesis processes; for blending (mixing).
- As a solvent for varnishes, paints, anti-corrosion coatings; in the rubber industry. 
- For degreasing and cleaning fabrics, electrical equipment, furs, leather.
– For washing metal parts, fittings, printed circuit boards, aircraft engines, cleaning parts after depreservation and before conservation.
– In the manufacture of rubber adhesives, oil and printing inks, mastics, electrical insulating varnishes; film-forming protective compounds; artificial fur, monolithic capacitors.
— As a solvent for extracting rosin, nicotine, vegetable oils from vegetable raw materials; bone fat; ozocerite from ore.
- Stain remover for greasy stains.
- To get such popular in everyday life
A car is a complex system of mechanisms that require proper care and following operating instructions. They are installed by the manufacturer and indicated in detail in the form of a list in the instructions.
Gasoline is, as you know, fuel. The durability of the car depends on its quality and basic characteristics. If the fuel is selected in accordance with the requirements, it will not be necessary to repair or replace it soon. Therefore, applying quality gasoline with the required set of characteristics, the driver can significantly reduce the cost of maintaining his car.
Today there are many varieties of fuel for the engine. What is their difference, advice will help to understand experienced motorists and technologists. Do right choice in this case it will be easy.
general characteristics
Gasoline is the resulting mixture. It is intended for internal combustion engines. Ignition in the system is forced. Gasoline "Ford", "Opel", "Lada", etc. may differ in a number of characteristics. This is due to the difference in the composition of the fuel.
The main characteristics that determine the scope of fuel for cars are fractional composition, detonation and chemical stability, saturated vapor pressure, etc. Before buying a particular variety, you should familiarize yourself with the basic properties of the fuel.
Knock resistance and octane rating
The flame in the engine normally spreads at a speed of 20-30 m/s. In some cases, it can increase significantly (up to 1500-2500 m/s). At this point, detonation occurs. It affects the performance of the engine. A wave is formed, which creates gasoline. "Opel", "Peugeot", "Mercedes" or a car of any other brand, in the event of such a situation, begins to overuse fuel.
Detonation reduces engine power. At the same time, its exhaust valves and pistons burn out. The octane number is used to indicate the resistance of a fuel to detonation. To determine it during the development and creation of gasoline, the manufacturer conducts tests under loaded and light conditions.
Methods for determining the octane number
Gasoline is a fuel that mixes with air in a certain proportion during engine operation. The octane number can be determined in two main ways. This is an exploratory and motor method. In the first case, the tests are carried out at low loads, and in the second - at high revs and heating temperature.
According to the test method, the types of gasoline are divided into 2 main groups. The first of them may have the letter "I" in the marking. This means that the octane number was determined using a research approach. If the marking includes the letter "A", this means that the detonation limit was measured motor way. The octane number can be set in both of these ways at the same time. The marking in this case has the letters "AI".
Classification by octane number
When deciding at a gas station with the question "what kind of gasoline is best to fill in the engine", you should consider the generally accepted classification by octane number. It is based on the research method.
According to her, there are 4 types of gasoline. There are "Normal-80", "Regular-92", as well as "Super-98" and "Premium-95". Along with the AI-80, the first variety is designed for truck engines.
Instead of leaded gasoline A-93 in cars today it is customary to use "Regular-92". For foreign cars, the motor of which is manufactured in accordance with all European standards and requirements, it is customary to use "Super-98" or "Premium-95". This fuel is able to extend the life of foreign car engine mechanisms, and also fully complies with high environmental requirements.
Gasoline quality
Owners of foreign cars, such as Mercedes, Ford, Peugeot, for which gasoline must meet high European standards, are puzzled by the issues of improving the quality of domestic fuel.
In our country, there is also a practice of improving the quality of fuel and octane number with the help of special additives. These are anti-knock components. To prevent the formation of soot in the engine, they are used in combination with a scavenger.
Antiknock agents contain lead. Evaporating from the engine exhaust gases, these substances enter environment by poisoning her. Therefore, the use of such technologies is a rather dubious method. It's better to buy gasoline first. High Quality that meets environmental requirements.
Incorrectly selected fuel
Trying to choose best gasoline for their car, many drivers still make mistakes. Each manufacturer calibrates the motor for a specific type of mixture. If the entire system, microprocessors and sensors are designed for Premium-95, the engine will not be able to fully operate on Normal-80.
At the same time, the knock sensor under loads, sharp accelerations will always work. This causes unstable operation of the motor, reducing its dynamics. If the knock sensor is not working properly, power unit may overheat. The valve and pistons are destroyed much faster. Fuel consumption starts to increase. Repairing the engine and other systems will cost more than constantly refueling the car with gasoline of the required grade.
How to evaluate the quality of gasoline?
Unscrupulous sellers can independently change the chemical composition of the fuel to obtain more profit. In order not to become a victim of fraud, you should purchase fuel from trusted distributors.
Gasoline is known to consumable on which the operation of the car depends. You can't skimp on its quality. You can check it yourself. To do this, gasoline is poured into a transparent container. The substance should be pale yellow without impurities.
If potassium permanganate is added to the container, the fuel should not turn pink. Otherwise, a change in color indicates dilution with water. At some branded gas stations, in order to avoid fakes, gasoline is dyed with different means.
If you put a drop of fuel on your palm and rub it, there should not be a greasy trace. Otherwise, this indicates an impurity. Also, any smell that is uncharacteristic of petroleum products should alert.
Chemical qualities of good gasoline
In search of an answer to the question of how much gasoline should be poured into the tank, you need to carefully study the operating instructions. These parameters are clearly specified by the manufacturer in this document.
During combustion, the maximum amount of heat should be released. Moreover, the thermodynamic characteristics should also be high. High-quality gasoline is easily pumped through pipelines and engine mechanisms. This indicator should not decrease in conditions of low temperatures, dustiness. The optimal evaporation rate allows you to store gasoline for a long time and ensure its rapid ignition when the engine is running.
Also, a good product protects the elements of the system from corrosion. Modern high-quality fuel, in addition, must be environmentally friendly. Decay elements should not poison the environment.
Expert opinion
To purchase high-quality gasoline, experts advise following a number of recommendations. This will avoid fraud on the part of sellers, keep the engine running at for a long time. First of all, you need to pay attention to the reputation of the implementer. Gas stations that value their name will never sell low-grade gasoline.
At such points of sale of fuel, there is always a buyer's corner, as well as relevant documentation on the right to sell gasoline. Even on old ones, but quality gas stations repaired, there is appropriate markings, warning signs and signs.
Should alert unreasonably low cost gasoline. On the quality of this product, as mentioned above, you should not save.
Gasoline is the fuel for automotive engines internal combustion, which is obtained as a result of the distillation of oil. Types of gasoline are divided into automotive, aviation, solvent gasoline and naphtha.
1 Octane number
Obtaining occurs when oil is heated and easily evaporating particles are released from it. heated at various temperatures and, accordingly, products of different grades are formed. To obtain a first-class substance, it is necessary to heat the oil to 100°C.
To ensure excellent engine performance, each type of energy source must meet certain requirements.
The operational parameter includes such a quality as good volatility (when homogeneous mixture from fuel and air with an optimal composition).
The ability of a fuel to resist spontaneous combustion during compression is called knock resistance. The value that characterizes it is nothing more than an octane number. It shows how much isooctane is contained in its mixture with n-heptane. Two carbons with opposite properties. Isooctane is one that burns but does not explode, n-heptane, on the contrary, tends to explode. What happens to gasoline if it contains a different amount of such elements?
The octane number (OC) of isooctane is taken as 100%, and the OC of another is equated to zero.
For determination, a single-cylinder engine is used, in which the compression ratio changes. By pouring a sample of fuel, knocking is detected by measurement. To obtain the same level of this property, a mixture of isooctane and n-heptane is added in various proportions. The octane number in such a mixture is the proportion of isooctane in it.
Such numbers belong different kind. According to the method of determination, they are divided into research and motor number. The difference lies in the subtleties of the loads experienced. In the first case, the behavior of the substance at small and medium loads, in the second, on the contrary, at large ones.
The octane number is one of the classifiers of gasoline grades.
The most common brands are AI-76, AI-91, AI-93, AI-95. Their marking indicates which method was used in determining the value of detonation resistance and the octane number itself. The designation rules were defined by the State Standard for the correct recognition of marks. Displayed as three groups of characters:
- The first letters are AI or A (automotive class, method for determining the octane number, I - research, A - motor).
- Octane number.
- Ecological class of gasoline.
For engines with a low compression ratio, oil grades with an octane rating of not more than 80 units are suitable.
For vehicles with a high degree compression - not less than 90. The color of the liquid does not change in any way depending on the type of octane contained in it, therefore, safe dyes (yellow, orange-red, blue) are added to distinguish brands.
2 Improving the quality of gasoline
To increase knock resistance means to improve the quality of this product. This is achieved by increasing the high-octane components. Due to the high cost of such a process, a cheaper method is used. It consists in adding special chemical formations - antiknock agents to the composition. One of the most common substances with similar properties is tetraethyl lead (TES). Usually it is added together with a scavenger in order to prevent carbon deposits in the engine. They are removed with exhaust gases. Getting into the environment, lead compounds poison everything that is possible. Such an antiknock agent is called leaded and it is dyed in different colors to warn of the danger of poisoning.
In contrast - low quality characterized great content paraffinic hydrocarbons (atoms are connected in a straight chain). The same carbons, but with a branched chain, increase the octane in the mixture.
3 Other types of gasoline
Aviation gasoline has incredibly high requirements for the quality of the resulting product. Its octane rating is much higher. Such a mixture is determined by the ability to resist the explosion, fractional and hydrocarbon compositions.
Such a product is produced through the direct distillation of petroleum with or without additives of various additives or ethyl liquid.
They are also labeled established rules GOST and are written as a fraction. Where is the oct. lean mixture in the numerator, and on the rich - in the denominator.
Oil heating products with a low sulfur content or low boiling point are used in solvents in the rubber and lacquer industry to extract a substance from a solution of oils of vegetable origin. They are also called "extraction gasolines" (heating temperature during production is 70-95°C). The same varieties of the substance, but with a lower boiling point, are used in hot climates during production.
Part of the liquid mixture of oil with a boiling point of up to 180 ° C is called naphtha, which mostly includes normal paraffins. Their production is characteristic, like all other types, of distillation methods, but with the addition of a small amount of secondary parts of the mixture. It is used as a raw material for the thermal decomposition of organic compounds to produce ethylene at petrochemical production enterprises.
The listed types of gasoline make up a small part of all existing ones. This product is classified not only by the content of octane in it, but also taking into account industrial and household properties.
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Is detonation resistance. Detonation - the process of rapid combustion working mixture with the formation of shock waves in the combustion chamber. It leads to burnout of the pistons and exhaust valves. TO outward signs detonation include: characteristic metallic knock, vibration, black color of exhaust gases, fluctuations in engine operation.
The first sign of detonation is a sharp ringing knock in the engine. Many motorists believe that it is knocking piston pins. However, in reality, the cause of knocking is the vibration of engine parts caused by the shock wave. Detonation occurs due to: a mismatch between the type of gasoline and the compression ratio of the engine (too low an octane number), early ignition, a large number of soot in the combustion chamber, engine operation at a fully open throttle, as well as low crankshaft speed.
Detonation properties are evaluated by octane number. This number is determined by two methods - research and motor. As a rule, in the designation of gasoline, along with the octane number, the method by which it is determined is also written. For example, the letter I - research. The higher the octane number, the greater the resistance to detonation, which means more power as well as economy.
High-octane gasolines are produced in two ways. The first complex technology, in which the proportion of high-octane components in production is increased (unleaded gasoline). Second, tetraethyllead gasoline additive (leaded gasoline). This method is simpler and cheaper. It is practically not used in developed countries.
When pouring leaded gasoline into your tank, be careful. Tetraethyl lead (and also tetramethyl lead abroad) significantly increases detonation resistance, for which, in fact, it is added. However, on cars equipped with a lambda probe and a catalyst, since lead will quickly lead to their breakdown.
Gasoline labeling
Our country produces gasoline of the following grades: A-72, A-76, A-80, AI-91, AI-92, AI-93, AI-95 and AI-98. There are leaded, low-leaded, unleaded, summer, winter varieties. Leaded grades are specially dyed. For example, A-72 is pink, A-76 is yellow, AI-93 is orange-red, and AI-98 is blue. There are two main brands abroad: "Premium" (1st grade, octane number 97-98) and "Regular" (2nd grade, octane number 90-94). In England and the USA, as well as some other countries, Super brand gasoline is produced, in which the octane number is 99-102.
Where is the best place to apply?
For passenger cars use gasoline with an octane rating of at least 91-92. In cars manufactured in the 90s, it is better to use fuel with an octane rating of at least 94.
The quality of gasoline is also determined by the level of contamination with impurities, acids, alkalis, organic compounds, sulfur compounds. Gasolines produced in the post-Soviet space often have reduced quality in terms of the above parameters. That's why fuel system must be equipped with a filter fine cleaning, which needs to be changed every 10,000 - 15,000 km. It is useful to completely flush the tank once a year. For engines with injection and a catalyst, use gasoline not worse than AI-95 unleaded or low-leaded.
Storage conditions
When gasoline is stored for a long time, its quality deteriorates, since the resins contained in it form compounds Brown, which settle on all parts, which affects their wear.
The processes of gasoline oxidation are influenced by a number of factors. Copper and its alloys accelerate it. Gasoline in a car tank, where there is a brass intake tube and a filter mesh, oxidizes faster than in an iron canister. Promotes oxidation and free access of air to the fuel. IN summer period oxidation processes proceed much faster.
When leaded gasoline is stored for a long time in a loosely closed container, volatile ethyl bromide leaves. This is a substance that is part of the ethyl liquid and removes lead oxides. After a while, there may be so little ethyl bromide left in the gasoline that it cannot remove the lead. This means that there will be more soot in the engine.
It is more efficient to store fuel in a tightly closed container and in a cool place. This is where canisters and similar containers come in handy. In the middle climatic zone, gasoline can be stored in tightly closed canisters without significant loss of quality for up to 12 months, and in a car tank - no more than 6 months. For the northern regions, the terms are increased by 1.5-2 times, and for the southern regions they are halved.
