Density of diesel fuel and other characteristics - what is their role in determining the quality of fuel

Everyone has heard the term diesel fuel, that is, diesel fuel, as it is also called for short, diesel fuel. It is believed that cars with diesel engines are much more economical, that is, less money is spent on refueling. But modern cars running on diesel fuel have high requirements for fuel quality. For old cars with diesel internal combustion engines, it’s easier; you buy diesel fuel from a tractor driver or truck driver at a cheap price and drive. And it is dangerous to fuel new expensive cars with diesel fuel, which is used to fuel, for example, Belarus tractors. The efficient operation of the internal combustion engine is determined by the characteristics of the fuel. The presence of impurities and poor filtration will lead to minor routine repairs, and then to major repairs. In addition to clean fuel, the density of diesel fuel must be appropriate.

Density is the amount of mass in grams or kilograms that is contained in one cubic centimeter or one cubic meter of volume (grams/cm3 or kg/m3).

The density of diesel fuel depends on temperature, that is, it is not constant.

Question: when does density decrease and when does it increase? When diesel fuel is heated, its density decreases, and the colder it gets, the density increases.

The density of the liquid (specific gravity of diesel fuel, in this case) is measured with a hydrometer. The mass of the hydrometer is divided by the volume that is in this liquid - this shows the density. To measure the density of diesel fuel, you need a hydrometer for petroleum products of type AN, ANT1 or ANT2. A hydrometer is similar in appearance to a thermometer for measuring temperature, but has two scales.

What does density say about the quality of diesel fuel?

If the hydrometer shows a high density of diesel fuel, this means that the fuel contains more heavy fractions. If there are a lot of heavy fractions, then evaporation and atomization in the combustion chamber of the cylinders deteriorate, and this leads to a loss of power of the diesel unit.

Table values

Basic measurements for diesel fuel are carried out at an ambient temperature of +20C. This is due to GOST. You should also take into account the brands of fuel, because they have their own physical characteristics. If you need a value regardless of temperature, you can find it out from the following table.

Based on the values, it is obvious that the density of winter diesel fuel is clearly less than the parameter for the summer grade of fuel. This ensures better fluidity of the liquid and reduces its pour point.

According to established standards, a summer grade should, under normal conditions, have a specific gravity of 8440 N/m3. A similar indicator for winter d/t is determined as 8240 N/m3.

You can independently weigh a clearly measured liter of fuel. It should reach the scale mark of 830-860 g, depending on the type.

It is worth knowing that summer diesel fuel in our country is marked with the letter “L”.

In the Middle Zone, this type is offered at gas stations from April to early to mid-autumn. It is important that the ambient temperature is not recorded below -5C (at -6C cloudiness occurs). When the value drops below -7-8C, the risk of liquid freezing increases significantly. As a result, blockages occur in the pipelines.

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The density of diesel fuel varies slightly depending on temperature (the table of brands is indicated above). One degree leads to a change in density by 0.75 kg/m3. A more detailed plate can be downloaded from the link.

Density of petroleum products

The density of a fuel is its specific gravity, namely the amount of mass per unit volume.

The density of the fuel largely depends on the density of the oil from which it is obtained. According to GOST R 52368-2005, the fuel density at a temperature of +15 °C should be in the range of 0.820-0.845 g/cm3, and according to GOST 305-82 it should not exceed 0.860 (at 20 °C)

The density of the fuel depends on the temperature, however, as for any other liquid: as the temperature increases, the density of the fuel decreases and vice versa - as the temperature decreases, the density of the fuel increases. There are special tables for converting fuel density depending on temperature. For diesel fuel, the temperature correction for density changes is, on average, 0.0007 g/cm3 per 1°C.

DENSITY OF PETROLEUM PRODUCTS

Accurate calculation of oil product density

In order to determine using this table the density of an oil product at a given temperature, it is necessary:

table of average temperature corrections for the density of petroleum products.

a) find the density of the oil product at +20oC from the passport;

b) measure the average temperature of the cargo in the tank;

c) determine the difference between +20oC and the average temperature of the cargo;

d) using the temperature correction column, find the correction by 1oC, the corresponding density of this product at +20oC;

e) multiply the temperature correction of density by the temperature difference;

f) subtract the product obtained in paragraph “e” from the density value at +20oC if the average temperature of the oil product in the tank is above +20oC, or add this product if the temperature of the product is below +20oC.

Examples.

The density of the oil product at +20oC, according to the passport, is 0.8240. The temperature of the oil product in the tank is +23oC. Determine the density of the petroleum product from the table at

this temperature.

We find:

a) temperature difference 23o - 20o = 3o;

b) temperature correction per 1oC according to the table for a density of 0.8240, amounting to 0.000738;

c) temperature correction by 3o:

0.000738*3=0.002214, or rounded to 0.0022;

d) the desired density of the oil product at a temperature of +23oC (the correction must be subtracted, since the temperature of the cargo in the tank is higher than +20oC), equal to 0.8240-0.0022=0.8218, or rounded to 0.8220.

2. The density of the petroleum product at +20oC, according to the passport, is 0.7520. The temperature of the cargo in the tank is -12oC. Determine the density of the petroleum product at this temperature.

We find:

a) temperature difference +20oC - (-12oC) = 32oC;

b) temperature correction per 1oC according to the table for a density of 0.7520, amounting to 0.000831;

c) temperature correction by 32o, equal to 0.000831*32=0.026592, or rounded 0.0266;

d) the desired density of the oil product at a temperature of -12oC (the correction must be added, since the temperature of the cargo in the tank is below +20oC), equal to 0.7520 + 0.0266 = 0.7786, or rounded 0.7785.

Winter diesel fuel classes

Five years ago, GOST R 55475 was introduced in Russia and is now used, regulating the requirements for diesel fuel used in winter. It is produced from middle distillate fractions of petroleum products. This diesel fuel has a reduced content of paraffin-forming hydrocarbons and can be safely used in diesel cars.

This standard regulates the grades of fuel for these vehicles (winter - W and arctic - A), as well as the filterability limit temperature - an indicator indicating the temperature values ​​at which the fluidity of diesel fuel decreases to almost zero. Filterability indicators are selected from the following standard range: -32ºС, -38ºС, -44ºС, -48ºС, -52ºС. It follows that diesel fuel of the Z-32 brand will be considered winter, having a filtration temperature of -32ºС, and diesel fuel of the A-52 brand will be considered arctic, with a filtration temperature of -52ºС.

The winter diesel fuel classes established by this standard determine:

1. The presence of sulfur in mg/kg: up to 350 relative to class K3, up to 50 relative to class K4 and up to 10 relative to class K5.
2. Flash point value, ºС: for fuel grade Z-32 – 40, relative to other brands – 30.
3. The actual outflow viscosity, mm2/s, which should be: for diesel fuel Z-32 - 1.5...2.5, for diesel fuel Z-38 - 1.4...4.5, relative to other brands - 1.2...4, 0.
4. The maximum presence of hydrocarbons of the aromatic group: relative to classes K3 and K4 of such compounds can be no higher than 11%!, relative to class K5 – no higher than 8%!

GOST R 55475-2013 does not define filterability and turbidity characteristics as specific temperature characteristics inherent in diesel fuel classes. The technical requirements only state that the temperature limit of filterability must exceed the cloud point by 10ºC.

Diesel fuel classification

To classify diesel fuel, two indicators are traditionally taken into account: the degree of sulfur content and the maximum cloud point. This is a standard adopted by the state, corresponding to the European system and specification EN 590. For the purposes of this article, temperature indicators are of greatest importance.

“Temperature” classification divides fuel into grades and classes, which are indicators of the lowest temperature at which the fuel can pass through the filter.

The maximum filterability temperature (t °C) is indicated in parentheses.

Depending on temperature indicators, diesel fuel is divided into three main types and one additional (last).

1. Summer diesel fuel. Remains liquid down to -5 °C. Recommended for use at temperatures above 0 (filterability t °C is not determined).
2. Winter diesel fuel. It should not thicken to temperatures below 35 degrees. Use in frosty conditions (-20 °C).
3. Arctic diesel fuel. Recommended for severe frosts from -45 degrees (-38 °C).
4. Interseasonal diesel fuel (-15 °C).

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Additionally, we advise you to read the material, which describes in detail the features of using antigel for diesel fuel.

For each of the three main types, its own standards for density and viscosity indicators are determined. It is these characteristics that determine the efficiency of the engine and when and what fuel to use. They are also often used to determine the quality of diesel fuel.

The viscosity standards are as follows:

• summer type - 3.8/6.0 cSt;
• winter type - 1.8/5.0 cSt;
• Arctic type - 1.5/4.0 cSt.

Density indicators will be discussed further.

Formulas for calculating the density, weight and volume of diesel fuel

The density of diesel fuel, its weight and volume is calculated using certain formulas in accordance with GOSTs.

Based on the fact that the density indicator directly depends on temperature, for the accuracy of calculations it is worth taking into account the correction factor and the ambient temperature indicator.

According to the formula, the density of diesel fuel is calculated as the ratio of the mass of the fuel to its volume.

• V = m/p, where
• V—volume;
• m—mass;
• p – density

when calculating the density of diesel fuel is taken:

• for summer fuel 860kg/m3;
• for winter fuel 840 kg/m3.

Accordingly, 1 kg of summer fuel is 1.19 liters, and 1 kg of winter fuel is 1.16 liters.

1 liter contains 0.860 and 0.840 kg of diesel fuel

The density of the petroleum product must strictly comply with regulations. The density recorded at 20°C is taken as a standard. To simplify calculations, special tables have been compiled in which, knowing the weight and volume of the product, as well as the temperature, you can easily find the required indicator.

The weight of diesel fuel is calculated by simply multiplying the density of the petroleum product by its volume. To calculate the mass of diesel fuel in tons, use the formula:

M(mass)=V (volume in liters)*p(density kg/m3)

To calculate the mass of summer fuel having a density of 0.860 kg/m3 with a volume of 1000 liters, we have the following value:

M=1000*0.860

This formula also applies to other types of fuel with different density parameters. Quantitative indicators so far are easily converted from tons to kilograms and vice versa. The calculation of volume, accordingly, is carried out using the inverse formula - the mass of the product is divided by its density. This calculation is very important when drawing up accounting documents for fuel, in which it becomes necessary to convert the weight of fuel into volume for the correct selection of containers.

Calculation of diesel fuel from tons to liters can be done using the formula:

V = (M / 0.850) x 1000, l.

where M is fuel in tons

The average value of 850 kg/m3 is most often used as an indicator of the density of diesel fuel.

Flash point of diesel fuel

Flash point is the temperature at which a flammable liquid releases sufficient vapor into the air surrounding it so that the air-vapour mixture above the surface of the liquid can be ignited by an ignition source. For safety reasons (transportation, storage), diesel fuel must have safety class AIII, i.e. it must have a flash point above 55°C. For example, containing less than 3% gasoline in diesel fuel can reduce the flash point to such a level that ignition is possible at room temperature.

The flash point of diesel fuel can be in the range from 52 ° C to 96 ° C, depending on the type of engine for which it is used and its operating conditions. Since diesel fuel is used in engines with a high compression ratio, diesel fuel must have a high flash point and a low auto-ignition temperature.

Why does diesel fuel consumption increase in winter?

In fact, the density of diesel fuel indicates how much energy the fuel will release. The higher the density, the more energy it will release. The coefficient of performance (COP) will be higher if the fuel density is higher.

In cold climates it is necessary to fill in winter diesel fuel. It has less density so that it does not harden and has good atomization.

Some truckers advise that if diesel fuel is frozen, add kerosene to it. I don’t know how this will affect the operation of the power unit, but I think it’s better to fill in diesel fuel in advance according to seasonality. There are also special additives, antigels for diesel fuel.

If you fill in summer diesel fuel, it clogs the fuel filter in cold weather. Then you will have to disassemble and clean.

Where did diesel fuel come from?

In the photo - diesel fuel, which appeared later than gasoline

So Rudolf Diesel has almost nothing to do with diesel fuel. He owns a patent for an internal combustion engine that runs on kerosene or fuel oil, and the fuel ignites not from a spark, as in expensive gasoline, but under high pressure. The Diesel engine was a three-meter structure that produced 17 horsepower and rotated at a speed of about 170 rpm. The efficiency of the Diesel unit was 26% and this was almost a revolution in 1893, because the steam engine was half as weak. The diesel fuel we are familiar with today appeared at the suggestion of Emmanuel Nobel. He bought a license from Rudolf Diesel and made the kerosene engine run on diesel fuel. And Diesel himself probably knew something extra, because one fine September evening in 1913 he left the house and never returned. This is how the Diesel unit would have worked, like a compressor or current generator, if Robert Bosch had not become interested in its design, he brought the diesel engine to life, equipped it with a high-pressure fuel pump, and was able to fit it under the hood of a Mercedes 5K3 truck. But that’s another story, we’re already distracted from diesel fuel.

Physical characteristics of diesel

Diesel fuel refers to products obtained after distillation of oil at special enterprises (refineries). The quality and composition of the finished liquid must meet strict standards. The density value is a parameter that is involved in determining the productive performance of the fuel under various conditions.

It is important to know that density demonstrates the number of kilograms of liquid in one cubic meter.

Experts know that this parameter is not constant and depends on external factors, the main one of which is the ambient temperature. A rise in the thermometer stimulates a decrease in density, and the reverse process increases the specific gravity of diesel fuel.

To obtain a specific value, a measuring device is used - a hydrometer. During the measurement process, the unit must be lowered into a container with diesel fuel. To carry out measurements in different liquids, different types of hydrometers are used. Measurements in petroleum products are carried out using models AN, ANT-1 or ANT-2 .

The hydrometer is made in the form of a glass tube, inside of which there is a graduated vertical scale. A greater degree of immersion demonstrates a lower density and vice versa.

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The increased specific gravity of the liquid is a consequence of the fact that it contains heavy hydrocarbon fractions. Because of this, the high-quality operation of the internal combustion engine may decrease, because the evaporation of the liquid deteriorates and its good atomization by the nozzles is not ensured. An additional negative from the presence of a large number of heavy particles is that soot and various deposits form on the working surfaces.

Diesel fuel: density, consumption, operation

The density of diesel fuel, which makes it possible to determine the climatic purpose of the fuel, affects the starting characteristics and operation of the engine. If you select the wrong diesel fuel or use low-quality fuel, the starting of the engine deteriorates, which does not develop the rated power and torque. When driving in difficult road conditions, insufficient engine power leads to the inability to carry the required load or to increased consumption of diesel fuel and excessive wear of the power unit.

What does density say about the quality of diesel fuel?

The specific gravity of diesel fuel determines the ratio of the fractions that make up the fuel. With an increased parameter, the mixture contains an increased volume of heavy hydrocarbons, which reduce the possibility of diesel fuel being sprayed by injectors into the combustion chamber. Due to the presence of heavy fractions with a high boiling point, the mixing of fuel particles and air deteriorates. To ignite the vapors, an elevated temperature is required, which leads to interruptions in the operation of the power unit and increased consumption of diesel fuel.

State standard

The standards for diesel fuel in force in the Russian Federation were partially adopted back in the days of the USSR (GOST 305-82). According to regulations, the density of fuel used in summer is 0.86 kg/l. When operating vehicles with diesel engines in winter, it is necessary to use diesel fuel with a density reduced to 0.84 kg/l. The fuel is used to power naturally aspirated engines or those with turbochargers. For the Arctic regions in winter, fuel with a specific gravity of 0.83 kg/l is supplied.

Diesel fuel specific gravity standards

Specific gravity standards are prescribed in GOST R 52368-2005 and 305-82 standards. Regulations stipulate the amount of impurities in the fuel composition (for example, sulfur), which negatively affect the composition of exhaust gases and the durability of fuel injection equipment. The standards prevent the introduction of aqueous solutions into the fuel, which corrode spray tips and damage filters and high-pressure pumps. Water with foreign impurities is separated using special settling tanks (filtration occurs due to the difference in the densities of the liquids).

Why does diesel fuel consumption increase in winter?

An increase in fuel consumption at low temperatures occurs due to the heating of the power unit and increased friction in a cold engine. When driving, fuel consumption corresponds to summer values ​​or differs to a lesser extent, since increased torque at low speeds reduces slipping of the drive wheels on snowy surfaces. Additional load is exerted by thickened oil in axle housings and planetary gearboxes; due to the increased resistance, fuel consumption increases slightly.

At low temperatures, air has an increased specific gravity, which leads to a violation of the composition of the working mixture. Motors with an electronic unit automatically adjust the fuel dose and injection phase, eliminating the negative effect of cold air. Engines with a mechanical high-pressure pump are not able to adjust to air temperature, which also affects fuel consumption. Cold air increases the drag coefficient, which slightly increases the cost of diesel fuel per 100 km of travel.

Why does diesel fuel freeze?

The composition of diesel fuel includes various fractions that thicken under the influence of low temperatures. The dependence of viscosity on the external temperature background is determined by density, which depends on the volumetric amount of fractions with an elevated boiling point. If water is present in the fuel, it sinks to the lower part of the tank, where it crystallizes when cooled below 0°C. Ice clogs the intake pipe, preventing diesel fuel from being supplied to the power unit. To restore engine performance, it is necessary to warm up the tank and fuel supply lines.

How to make sure you fill up your winter diesel fuel

When the winter season begins, special fuel for diesel engines appears at fuel pumps; information about the type of fuel is indicated on the pumps and in the gas station premises. The basic technique is based on pouring 50-100 ml of fuel into a transparent container, which is placed in the freezer compartment of the refrigerator. At a temperature of -20...-22°C, the liquid should not become cloudy (turbidity indicates the formation of a suspension of solid paraffin). For arctic varieties of diesel fuel, the turbidity threshold is at -34°C (not reached in the refrigerator).

How to check the density yourself

To check the correctness of fuel density, the following methods are used:

1. Based on the fluidity of liquid applied at -10°C and below to a metal plate. High-quality fuel remains liquid, and the formation of cloudy streaks is not observed in the composition. If the fuel thickens or becomes cloudy, it is prohibited to operate the vehicle in winter. The engine will start, but when driving, the process of crystallization of diesel fuel will begin, which will lead to immobilization of the car.
2. To accurately determine the density, an oil hydrometer is used (for example, model ANT-2, designed for densities from 830 to 910 kg/m³). A portion of fuel is poured into the container, then the tank is heated to a temperature of 20°C (controlled by a thermometer). The device is lowered into the liquid, the resulting value is checked against the standard specific gravity corresponding to the type of diesel fuel.
3. At temperatures below -20°C, a quick way to determine the quality of diesel fuel is the drops that remain on the nozzle of the refueling nozzle. If the liquid has a thick consistency or the solution is cloudy, then pouring fuel into the tank of the car is not recommended. If refueling has already been done, then you should dilute the fuel with high-quality diesel fuel, this will reduce the temperature at which crystallization begins.

DT density change step

The concept of diesel fuel weight measurement step means a correction factor equal to 0.0007 units. For example, at a temperature of -30°C, the density of the Arctic type of fuel will increase by 50*0.0007 = 0.035 g/cm³. With a standard value of 0.83 g/cm³, the parameter will increase to 0.865 g/cm³.

Everything has its time

What happens to summer diesel fuel at low temperatures? Just as water solidifies at freezing temperatures, summer-quality diesel fuel also crystallizes. Result: the fuel increases its viscosity and clogs the fuel filters. Thus, the engine can no longer receive high-quality diesel fuel in the required volume. The warning signal about impending troubles will come when stable frosts set in.

In the case of winter diesel fuel, the flow point is lowered, so that diesel fuel does not crystallize. Winter fuel for diesel cars exists in several classes, and additional differentiation is often made between traditionally “winter” and “polar”, arctic class fuel. In the latter case, the performance of diesel fuel is maintained even at very low temperatures.

Replacing diesel fuel grades is usually done by the gas station operators themselves. Before refueling, make sure that there is no summer fuel in the tank.

Calculation of specific gravity for 20 C

1. Measure the density and average temperature of diesel fuel.
2. Calculate the difference between the actual temperature and 20 ◦ C.
3. Multiply the temperature difference by the correction factor.
4. If the actual temperature is less than 20 ◦ C, then subtract the result of calculating the third point from the density value at a given temperature. If the liquid is warmer than +20 ◦ C, then these values ​​​​need to be added.

For example, the density of fuel at a temperature of 0 ◦ C is 0.997 g/cm 3 . The difference between the actual temperature and 20 ◦ C is 20. Then 20 × 0.0007 = 0.014 g/cm. Since at 20 ◦ C the density of the fuel will be less than at 0 ◦ C, it is necessary to subtract the correction value from the density at 0 ◦ C - 0.997-0.14 = 0.857 g/cm 3 . To convert the result from grams per cubic centimeter to kilograms per cubic meter, you need to multiply the value expressed in grams per cubic centimeter by 1000. That is, the specific gravity of our diesel fuel at 20 ◦ C will be equal to 857 kg/m 3. This allows us to make the assumption that, judging by the calculation results, it is more likely to be summer than winter. It is impossible to make an exact conclusion about what season the fuel is intended for based on its density.

Relationship between fuel density and diesel efficiency

Since the combustion of diesel fuel, which has a high specific gravity, is accompanied by the release of more energy than the combustion of less dense fuel, it is obvious that the use of summer fuel is more economical. However, its use to increase diesel efficiency in the cold season is not possible. This is explained by the fact that in addition to kerosene-gas oil hydrocarbons, which contain the main energy reserve of the fuel, its composition also includes paraffins dissolved in them. The latter, even with a slight decrease in fuel temperature, harden, thickening the fuel and worsening the permeability of the fine fuel filter. As a result, the ability of fuel to be pumped through the power system and sprayed into the engine cylinders deteriorates. Therefore, winter diesel fuels contain additives that slow down the hardening of paraffins and the thickening of diesel fuel to a gel state.

These additives, while reducing the concentration temperature of the fuel, have no effect on its density at all. It is logical to assume that if you add an antigel additive to summer diesel fuel, the result will be economical winter fuel. But this is far from true. Because the additive will only lower the freezing point of paraffins dissolved in the fuel.

The diesel fuel itself will not become less dense, which means that as the temperature drops, it will thicken significantly, which will make it difficult to spray it in the combustion chambers and move along the fuel line. In addition, it is a mistake to believe that by pouring an additive into frozen diesel fuel, we will ensure that the paraffins in it melt and it will regain its fluidity.

To summarize the above, it should be noted that density is very important for winter fuel. For summer, such parameters as sulfur content and cetane number are more important. The fact that diesel is less economical in winter than in summer is, of course, largely due to diesel fuel being less dense than in summer, but not only that. Snow on the roads also does not contribute to efficiency.

Diesel fuel express testing method

In everyday life, the owner of a diesel engine rarely needs to check the quality of the fuel. Since he usually refuels his car at the same gas stations, the quality of the fuel at which has been tested during the operation of the car, and most likely suits the car owner. If you are in an unfamiliar place in winter, express analysis of winter diesel fuel in frosty weather can be carried out using the simple method described below.

How to check the density of diesel fuel yourself?

There are several ways to check the density of diesel fuel.

Method one

1. The test is carried out at temperatures from -10 ˚С.
2. A small amount of fuel is poured onto the metal surface.
3. Look for the presence of turbidity and the degree of change in fluidity.

If the fuel does not solidify and flows well, the quality is high. The presence of slight haze and increased viscosity indicate poor quality. Good winter fuel freezes at a temperature of -45 ˚С.

Method two

1. Buy a hydrometer.
2. Fill a small container with diesel fuel.
3. Place the vessel in a place with a temperature of +17 to +20 ˚С and wait for the fuel to warm up. You can leave it overnight.
4. After some time, measure the density with a hydrometer, comparing with the accepted standards mentioned above.

Method three

Take a fuel nozzle and analyze the droplets of fuel at the end. If they freeze, the quality of the fuel leaves much to be desired.

You can carry out an additional check and fill the car with this fuel by mixing fresh fuel with what is in the tank.

Density of diesel fuel in summer and winter

The fuel used in summer and winter differs in its basic characteristics.

For winter, fuel that has the following indicators is suitable:

• low density;
• low viscosity;
• does not freeze at a temperature of -45
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Low viscosity density allows the fuel not to turn into a gel and circulate freely inside the internal combustion engine. In cold weather, the use of high-density fuel is strictly prohibited in order to avoid problems with the filter system.

Summer fuel is characterized by:

• high density (not less than 0.86 kg/l);
• inflammability (withstands temperature rises up to +45
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  WITH).

When winter fuel is used in the summer, engine power decreases and smoke levels increase.

The best time for summer fuel is April - September, if the temperature does not drop below -4

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C. Otherwise, the diesel fuel will become cloudy, and when the temperature drops another few degrees, it can lead to problems with engine operation.

Additives (additives)

Improving quality by adding additives, which has been a common practice for gasoline for many years, has recently become popular for diesel fuel (Super and Premiom diesel fuels). The main additives used are those that have multiple effects:

• additives to improve ignition increase the cetane number and are responsible, in particular, for a “softer” combustion;
• detergents are used to prevent coking of injectors;
• corrosion inhibitors (retarders) are necessary to prevent corrosion of metal parts (if water gets into the fuel system);
• Antifoaming additives serve to facilitate filling the fuel tank.

The total concentration of additives usually does not exceed 0.1%!, so that the physical characteristics of the fuel such as density, viscosity and boiling curve do not change.