Diesel fuel is a rather old, but still demanded type of fuel for piston diesel engines. And if earlier its scope was limited due to poor quality and toxic combustion products, now more and more cars are equipped with diesel engines, and scientists are working to improve performance and make diesel fuel environmentally friendly.
What is diesel fuel?
Diesel fuel is a heavy fraction of oil, the basis of which is hydrocarbons with a high - 200-350 ° C - boiling point. It is used as fuel in diesel engines and gas diesel engines.
Why exactly in diesel? Because, unlike gasoline engines, in which a mixture of gasoline and air is ignited by a spark, in a diesel piston engine the fuel spontaneously ignites under strong compression.
Externally, diesel fuel is a transparent, with a higher viscosity than gasoline, liquid, the color of which can be yellow and brown in different shades. Resin in the fuel composition affects color.
When burned, any fuel produces energy. Diesel fuel, in addition to this main task, performs several more important functions in the operation of the engine. It lubricates friction surfaces in fuel injectors and pumps, cools the walls of the combustion chamber and regulates the exhaust parameters on the engines.
Diesel use
Sea and river vessels, diesel locomotives, military and agricultural equipment, trucks - almost all heavy vehicles run on diesel engines.
The last decades, a car that runs on diesel fuel has become popular in the developed countries of Europe. Fuel consumption is 40% less in a diesel engine, and traction, power, maneuverability and safety of exhaust gases are greater than in gasoline.
Diesel is economical in operation and at a cost of fuel. It is used in diesel electric generators of stationary and mobile power plants, in boilers of autonomous heating systems.
Hydrochloric oil, which is popularly called simply diesel fuel, is a residual diesel fuel with a high viscosity and boiling point up to 400 ° C. This type of fuel is used for low-speed engines in water and rail transport, tractors. In addition, solarium impregnate the skin in the leather industry. Hydrochloric oil is part of the cutting fluid in the processing of metals by cutting and quenching fluid during their heat treatment.
Main characteristics
Cetane number (the main parameter of diesel fuel) characterizes the flammability of the fuel. It determines the period of delay in the combustion of the working mixture, that is, the time that elapses between the injection of fuel into the cylinder and the beginning of its combustion. The shorter this time period, the higher the cetane number, and the shorter the engine warm-up time. True, this increases the smokiness of the exhaust, which becomes critical with a cetane number above 55.
For the processes of injection and fuel injection, its viscosity is important, on which the lubricating characteristics depend
Its density and efficiency depend on the density of diesel fuel , because the higher the density, the more energy is generated during combustion.
An important characteristic is the amount of sulfur that diesel contains. These are sulfur compounds that reduce the corrosion resistance of the fuel system.
The quality of diesel fuel is also evidenced by the limiting filterability temperature, that is, such a temperature at which diesel fuel thickens so much that it no longer passes at all or passes very slowly through a filter with certain dimensions.
It is below the cloud point, that is, the temperature at which the paraffin contained in the fuel begins to crystallize.
Types of diesel fuel
Until 2015, diesel fuel in Russian standards was divided by type. In the state standard, introduced in January 2015, the division coincides with the division into environmental classes in accordance with the European standard and occurs depending on the sulfur content in the fuel. Sulfur content of not more than 350, 50 and 10 mg / kg corresponds to type I, type II and type III according to the obsolete and environmental classes K3, K4 and K5 according to the new state standard, respectively.
It is not recommended to use fuel in which high sulfur content, as this increases harmful emissions into the atmosphere, accelerates corrosion and wear of the fuel system elements, respectively, increases the cost of frequent replacement of filters and oil.
As a rule, the improvement of some properties leads to the deterioration of others. Lowering the sulfur content is a decrease in the lubricating properties of diesel fuel. Therefore, to preserve one of the main functions, various additives are added to the fuel.
Grades of diesel fuel
Varieties of diesel fuel differ in temperature below which the fuel cannot be used. The filtering temperature limit is used as a criterion. Moreover, summer and off-season diesel fuel is broken down by grades with this indicator not lower than -20 ° .
Grade A is characterized by a temperature of at least 5 ° C above zero. For each subsequent grade B, C, D, E, and F, the indicator decreases by 5 ° C.
An example is diesel fuel EURO, grade C, type II and III, or in the new version of environmental classes K4 and K5 with a filterability temperature of up to five degrees below zero and a sulfur content of not more than 50 and 10 milligrams per kilogram of fuel.
Diesel fuel classes
The division into classes of diesel fuel for winter or a cold climate occurs not only by the filterability temperature, the second characteristic is the cloud point.
In winter and Arctic diesel fuel at low temperatures, crystallization of paraffin begins, which degrades performance.
| Diesel class | Filtration limit temperature, ° | Cloud point, ° |
1 | 0 | -20 | -10 |
2 | 1 | -26 | -16 |
3 | 2 | -32 | -22 |
4 | 3 | -38 | -28 |
5 | 4 | -44 | -34 |
If in the designation of diesel fuel after the designation DT there is not a letter, but a number, then this fuel is winter or Arctic.
Diesel fuel brands
According to their physicochemical properties, operational characteristics, and application conditions, diesel fuel is divided into four types, which are marked with capital letters of the alphabet:
- Summer (L), which includes fuel grades A, B, C, D with a maximum filterability temperature from +5 to -10 ° . This diesel fuel can be used at temperatures not lower than 0 ° C.
- Off-season (E), grades E and F, with temperatures up to -15 and -20 ° , respectively, is used in autumn, when the air temperature ranges from +5 to -5 ° .
- Winter (W), which is divided into classes 0 to 3 and the filterability temperature in the range from -20 to -38 ° and is used at an air temperature not lower than minus 20 ° .
- Arctic (A) class 4 fuel with a maximum filterability temperature of minus 44 ° C and an ambient temperature of minus 50 ° C (in documents, a negative value is often accompanied by the word “minus” rather than a badge to avoid inaccuracies).
Fuel marking
Diesel fuel brands include name (DT), grade or class depending on the conditions of use and environmental class. That is, only two parameters are indicated in the brand: sulfur content and ultimate temperature of filterability.
Today you can find the designations both new and outdated, for example, DT winter EURO 5 grade F, which stands for winter diesel fuel with a sulfur content of not more than 50 mg / kg and a maximum filterability temperature of minus 20 ° , that is, the most used in conditions Russian winter with high requirements for environmental friendliness fuel.
Until now, such markings are also found: L-0.2-62, that is, top-grade summer fuel indicating the amount of sulfur (200 mg / kg) and a flash point of 62 ° C. Flash point is not the main indicator, but with other characteristics being equal, fuel with a higher temperature is considered the best for fire safety.
How to store diesel fuel
For an ordinary consumer having a personal car with a diesel engine, the question of storing diesel fuel is not worth it.
But for industries where fuel is bought in bulk and stored for a long time, the storage problem is very relevant.
Storage of diesel fuel is possible at a temperature of 20 ° C for a year and at a temperature above 30 0 C from six months to a year in sealed containers, protected from direct sunlight.
During storage, the fuel must not come into contact with copper, brass or zinc so that the fuel is not clogged with the products of chemical reactions with these metals. In addition, it should be protected from moisture and dust and should not have additives that could disintegrate during storage. For example, additives with a high environmental friendliness class are added to diesel oils to increase their lubricating properties, which decompose very quickly.
The efficiency of this fuel is high, the scope of its application is growing steadily. New brands of diesel fuel and new sources of its production appear. Now there are already new developments, and diesel fuel is produced not only from oil. Maybe the future belongs to diesel from vegetable oils.