At present, with rather high prices for gasoline, diesel fuel is becoming more and more popular. Many motorists prefer this type of fuel. However, the question often arises: how to determine its quality?
Types of diesel fuel
In accordance with the GOST standards adopted in 2006, three types of diesel fuel (diesel fuel) are produced in Russia:
- summer, with the letter "L";
- , with the letter "З";
- arctic, with the letter "A".
- 350 mg - European standard "Euro-3";
- 50 mg - European standard "Euro-4";
- 10 mg - European standard "Euro-5".
Determining the quality of diesel fuel by appearance
It is possible to check diesel fuel, without resorting to complex laboratory tests, by its organoleptic characteristics or, as they say, “by eye”. To this end, a small amount of fuel must be poured into a transparent container and left for a while.
After the test diesel fuel has settled, it is compared with a good quality oil sample. Poor-quality diesel fuel will differ in a darker color, and sediment will appear at the bottom of the container. If there is water in the test sample, it will settle to the bottom in a visible layer.
Laboratory testing of diesel fuel
If there are doubts about the quality of the fuel, then you should ask the seller to show the quality certificate for this product. Such a document must have all the data on the sold diesel fuel.
A small amount of diesel fuel can be poured into a canister and taken to the laboratory, where it will be checked for the presence of water and various mechanical impurities. The presence of sulfur in the fuel and its amount is determined using x-rays. The presence of this substance in the car most affects the catalytic converter, as well as the environment. Diesel fuel with a large amount of sulfur has a harmful effect on human health. Sulfur exhausts return to the earth in the form of acid rain, which causes diseases of the upper respiratory tract and destroys green spaces.
Through a laboratory test, the cetane number can be checked. It should not be lower than 45. The engine power and its efficiency largely depend on this indicator.
Analysis of the concentration of polycyclic hydrocarbons will help determine the level of carcinogens in exhaust gases. The flash point (it must be above 55 degrees C) is checked in special closed crucibles. This study helps to establish the presence of gasoline in diesel fuel.
Diesel fuel quality plays a big role: its low quality leads to the rapid wear of equipment parts, reduces work efficiency. How do you know if the fuel is good quality or not? There are several main characteristics of diesel fuelby which one can judge its quality.
The main characteristics of the fuel that affect its quality
cetane number
The most important characteristic is the cetane number (tsch), showing the ignition rate of diesel fuel in the engine. The CF of high-quality fuel has a value from 40 to 55. If CF is less than 40, then diesel fuel ignites slowly, as a result, the engine wears out quickly, and at a value greater than 60, fuel consumption and exhaust gas volume increase.
Fractional composition
Another indicator of quality is the fractional composition, which is determined by the evaporation temperature of the fuel. If the fractional composition becomes too high, then there is a rapid formation of carbon deposits and dilution of the oil. At low air temperatures, diesel fuel is often diluted with kerosene, which, on the one hand, facilitates the ignition of this fuel at low temperatures, and on the other hand, the fractional composition becomes too large, which leads to the already mentioned negative consequences.
Viscosity
The quality of diesel fuel also depends on the viscosity. On the one hand, it should not be too viscous, because due to the uneven process of its combustion, the components of the engine are quickly destroyed. On the other hand, it should not be too thin either, as the fuel pump will not be able to lubricate well. The optimal viscosity for summer diesel fuel is from 3.0 to 6 cSt, for winter - from 1.8 to 5.0 cSt.
In addition to the above factors, the quality of the fuel is affected by the sulfur content. Sulfur leads to the oxidation of engine oil, which leads to severe pollution of the environment by exhaust gases. On the other hand, sulfur is needed in fuel to lubricate engine parts to reduce wear. The optimal sulfur content in diesel fuel is from 0.15 to 1.5%.
How do you define quality yourself? The most common surrogate is a mixture of summer diesel fuel and kerosene. Low-viscosity marine, furnace or gas condensate can be passed off as diesel fuel. Only laboratories can test it. There is an artisanal way. It is necessary to pour fuel into a transparent container and let it stand for a while. Low-quality diesel fuel often has a darker tint compared to high-quality diesel fuel. In addition, you need to pay attention to the sediment, which should not be there.
How to determine the quality of diesel fuel yourself and not only ..
Of course, every car owner expects that when refueling, he fills in a high-quality oil product that complies with GOST R 52368-2005, which exactly copies the EN-590 euronormal and meets Euro-4 and Euro-5 standards.
After all, the owner of a diesel car is interested in its flawless operation, reliability, minimum fuel consumption and long service life.
However, all this can cross out the insufficiently high quality of diesel fuel (DF).
Parameters that determine the quality of diesel fuel
So, high-quality diesel fuel is the key to the efficient operation of your car.
Each manufacturer (refinery) provides a special quality passport for diesel fuel, which is a guarantee that you are refueling a quality product. The passport contains all the key characteristics and quality indicators of diesel fuel, which include:
1. Cetane number. This is the most important parameter that shows the ignition rate of the fuel in the engine. The high quality of diesel fuel is guaranteed by the CCH in the range of 40-55. When the CCH is less than 40, diesel fuel will ignite slowly, and engine wear will occur very quickly. A value greater than 55 threatens with high fuel consumption and exhaust volume.
2. Fractional composition Another indicator of quality is the fractional composition, which is determined by the evaporation temperature of the fuel. If the fractional composition becomes too high, then there is a rapid formation of carbon deposits and dilution of the oil. At low air temperatures, diesel fuel is often diluted with kerosene, which, on the one hand, facilitates the ignition of this fuel at low temperatures, and on the other hand, the fractional composition becomes too large, which leads to the already mentioned negative consequences.
3. Viscosity The quality of diesel fuel also depends on the viscosity. On the one hand, it should not be too viscous, because due to the uneven process of its combustion, the components of the engine are quickly destroyed. On the other hand, it should not be too thin either, as the fuel pump will not be able to lubricate well. The optimal viscosity for summer diesel fuel is from 3.0 to 6 cSt, for winter - from 1.8 to 5.0 cSt.
4. Sulfur content Sulfur provokes the oxidation of engine oil, and this greatly pollutes the environment with exhaust gases. The less it is in the fuel, the longer the catalytic converter lasts. However, sulfur is indispensable, it provides lubrication of engine parts and reduces their wear. High-quality diesel fuel should have a sulfur percentage of 0.15-1.5%. With a sulfur concentration of less than 50 mg / kg, the neutralizer will work properly for more than tens of thousands of kilometers, and at the "GOST" 2000 mg / kg, it will cease to function effectively after several refuelings: sulfur, interacting with the precious metals of the neutralizer, reduces their chemical activity to nothing . Nevertheless, sulfur is not only the worst enemy of converters, but also the best friend of the rubbing vapors inside diesel fuel equipment. After all, they are lubricated exclusively with diesel fuel, the anti-friction and extreme pressure properties of which directly depend on the concentration of sulfur: the more it is, the better. Therefore, anti-wear additives must be added to low-sulphur fuel, and lubricity must be normalized.
7. Flash point. Determines the safety conditions for the use of fuel in diesel engines; the presence of sulfur compounds, unsaturated hydrocarbons and metals, which characterizes carbon formation, corrosion, wear.
The importance of checking diesel fuel for quality
Cases when “branded” gas stations or private gas stations (including franchise stations) do not always sell the declared quality product are not rare. When refueling diesel fuel, require a quality certificate. Unfortunately, even fuel from a trusted manufacturer can be of poor quality. And there are many reasons for this (from the manufacturer’s dishonesty to the “uncleanliness” of suppliers and the implementers themselves, operators). At different stages, diesel fuel can be subjected to various processing, dilution and other operations that reduce its quality. The most common surrogate option is summer diesel fuel mixed with various modifiers, including kerosene, which reduces the lubricity of diesel fuel and, unfortunately, it is possible to establish the presence of kerosene only in laboratory conditions. Also, under the guise of diesel fuel, they can sell similar in color marine fuel (low viscosity), heating oil, and even gas condensate. For those who buy large quantities of fuel (for example, a car depot), we recommend that a control laboratory analysis of the quality of diesel fuel be carried out.
Self test diesel fuel
The easiest way to determine the quality of diesel fuel is quite simple, pour the fuel into a transparent vessel, cork it with a cork and defend it. Poor quality fuel will soon take on a dark hue and also precipitate. The presence of water will also form a separate layer.
1. To determine the presence of mechanical impurities, pass the fuel through a paper filter. Good quality DT will leave a small and light spot. Low quality diesel will leave a larger and darker stain on the filter. High-quality diesel fuel has a weak, unsharp odor, has a color from light brown to brown with a bluish tint, after evaporation leaves a greasy spot on a sheet of clean paper, while gasoline evaporates without a trace. But everyone is well aware that all these studies are quite relative, and more accurate indicators can only be obtained by conducting research in the laboratory.
The owner of a diesel car still has to be careful with an unscrupulous gas station.
Practice shows that when refueling diesel fuel, a typical underfilling of fuel often occurs, so depending on the appetites of the gas station, underfilling can be from 50 ml to 800 ml per 5 liters of fuel. Good luck with your trips!
For any vehicle, the quality of the diesel fuel used in it is of great importance. Usually, bad diesel fuel leads both to a decrease in the efficiency of the equipment and to the rapid wear of all its components. Accordingly, many of us are interested in the answer to the question of whether how to determine the quality of diesel fuel. There are several main characteristics of diesel fuel by which its quality can be judged.
The most commonly used feature is cetane number of diesel fuel. It shows the ignition rate of diesel fuel in the engine. The cetane number of high-quality diesel fuel is in the range from 40 to 55. At a value less than 40, diesel fuel ignites slowly, as a result of which the engine wears out quickly, and at a value greater than 60, fuel consumption and exhaust gases increase.
The next important characteristic of diesel fuel is viscosity. On the one hand, diesel fuel should not be too viscous, because otherwise, due to the uneven process of its combustion, the components of the engine are quickly destroyed. On the other hand, it should not be too liquid, otherwise the fuel pump will not be well lubricated. The optimal viscosity value for summer diesel fuel is in the range from 3.0 to 6 cSt, and for winter - from 1.8 to 5.0 cSt.
Another indicator of the quality of diesel fuel is its fractional composition. It is determined by the evaporation temperature of diesel fuel. It is important that the fractional composition is not too high, otherwise rapid wear of nozzles, carbon deposits and oil dilution are almost inevitable. Unfortunately, in the northern regions of our country, diesel fuel is often diluted with kerosene, which, on the one hand, facilitates the ignition of this fuel at low temperatures, and on the other hand, the fractional composition becomes too large, which leads to the already mentioned negative consequences.
Like cetane number and viscosity, sulfur content has a dual effect on the quality of diesel fuel. On the one hand, sulfur leads to the oxidation of engine oil and, which is especially important today, to more severe pollution of the environment by exhaust gases. On the other hand, sulfur in the fuel is still indispensable, otherwise it ceases to properly lubricate engine parts, thereby leading to their rapid wear. The optimal sulfur content in diesel fuel is in the range from 0.15 to 1.5%. In conclusion, it should be said that today on the Internet and newspapers you can find a lot of ads like "diesel fuel in Moscow", "sale of winter diesel fuel", "delivery of diesel fuel", etc. Many of them are provided by really bona fide companies selling diesel fuel specifications which is supported by all necessary documents. However, still no one is immune from buying bad fuel, because its quality cannot be determined by its appearance. Therefore, the best way to protect your equipment from low-quality diesel fuel is to check the supplier's documents confirming the quality of his products, and conclude an agreement with him, according to which he will be responsible for any breakdowns that have arisen due to poor fuel characteristics.
In order to improve the quality of diesel fuel, you can use special additives.
In 2007, the global car market was looking forward to the release of the BMW 1 Series Convertible. But when the official press release for the Russian market came out, our compatriots were in for a disappointment akin to that experienced by a child left on New Year without a gift. Almost all diesel modifications were accompanied by the postscript “(NOT supplied to Russia due to poor fuel quality)”, however, for the remaining gasoline versions, a significant part of the options was not available for the same reason.
So what scares the world's largest automakers in our diesel fuel, refusing to supply cars with latest generation diesel engines to our market with the wording "... due to poor fuel quality"?
To do this, you need to figure out what diesel fuel is and what it is eaten with.
Diesel fuel has a number of specific characteristics that determine not only the efficiency of the engine, but also affect the service life of the fuel system components.
The main characteristic is considered cetane number(similar to the octane number of gasoline). It characterizes the operation of the engine in terms of ignition of diesel fuel and its combustion. From the cetane number, in turn, depends on the power, smoke and noise of the engine. The usual range of cetane values ranges from 40 to 50. In fact, this figure means the ignition delay time (the length of time from the supply of fuel to the cylinder until it ignites). A higher cetane number means a shorter ignition period, and therefore better combustion of the fuel. In addition, with its increase, the environmental characteristics of the exhaust are improved. However, if this indicator exceeds 60, then the increase in engine power stops. In turn, diesel fuel with a low cetane number is easier to produce, therefore, in practice, diesel fuel is produced with a cetane number of at least 40-45.
cetane index is the calculated cetane number before adding a cetane booster to the fuel. The value of the cetane index in order to avoid an overdose of additives should be as close as possible to the cetane number. The cetane index actually determines the quality of the fuel in the intermediate production cycle.
Fractional composition- along with the cetane number, it is one of the most important indicators of the quality of diesel fuel. It affects fuel consumption, exhaust smoke, ease of starting the engine, wear of rubbing parts, carbon formation and coking of nozzles, and burning of piston rings.
Average evaporation(temperature at which 50% of the initial volume of fuel boils away) characterizes the working fuel fractions. It is they that provide starting, warming up, throttle response and stability of the engine, and also determine the characteristics of transient conditions.
The boiling point of 95% fuel. Determines the completeness of fuel evaporation in the engine. At too high values, the fuel does not have time to completely evaporate and condenses on the internal surfaces of the combustion chamber, leading to increased carbon formation, oil dilution and accelerated wear of parts of the cylinder-piston group and valves.
Flash point in closed cup- the lowest temperature at which fuel vapors are capable of flashing when an open source of fire appears, without forming stable combustion. The flash point determines the safety conditions for the use of fuel.
Mass fraction of sulfur is the amount of sulfur present in the fuel. The presence of sulfur in the fuel has both negative and positive aspects. On the one hand, an increased sulfur content in the fuel worsens the environmental parameters of the exhaust, leads to the formation of sulfuric and sulphurous acids in the lubrication system, which provoke the acceleration of engine oil oxidation. This leads to a decrease in the lubricating, antiwear, extreme pressure and detergent properties of the oil and the formation of carbon deposits in the combustion chamber. Therefore, when the engine is running on fuel with a high sulfur content, it is necessary to reduce the service intervals.
However, a decrease in sulfur content leads to a deterioration in the lubricating properties of the fuel, which leads to accelerated wear of high-pressure fuel pump parts and fuel injectors.
Kinematic viscosity and density- determine the possibility of normal, uninterrupted fuel supply, the formation of a fuel-air mixture and the operability of the filtration system.
Lubricity- a characteristic showing the ability of hydrodynamic and boundary lubrication of the moving parts of the injection pump. Determines the service life of the fuel system elements.
Fuel purity- determines the efficiency and reliability of the engine, especially fuel equipment. In the friction pairs of fuel pumps, the gaps are 1.5-4.0 microns, respectively, particles whose size exceeds these values leads to accelerated wear of parts.
Carbon soot, or rather, the ability to form it. Depends on the quality of the fuel. The lower it is, the more intense the carbon deposits are formed on the internal surfaces of the combustion chambers, which eventually leads to a gradual decrease in engine power.
Fuel density - energy index of diesel fuel. The higher the density, the more energy is generated during the combustion of the mixture and, accordingly, the efficiency and economy indicators increase.
cloud point - the temperature at which the process of crystallization of the paraffin contained in the fuel begins. At this temperature, paraffin is unevenly distributed in the volume of fuel, forming a kind of "clouds".
Blockage point- the minimum temperature at which the fuel is able to flow into a channel with a diameter of 45 microns. The value of the blockage point temperature is directly related to the cloud point temperature. Lowering the temperature to this value leads to clogging of the fuel filters with paraffin crystals.
Fireproof slag- the indicator affects the degree of purity of the fuel. Almost any diesel fuel contains a certain amount of non-combustible, hard-to-filter metal inclusions - slags.
As you can see, there are a lot of characteristics that affect the quality indicators of diesel fuel. And the main trouble of Russian diesel fuel is still a significant proportion of oil refineries operating on equipment manufactured back in the USSR. Accordingly, their products are fully suitable for diesel engines those years, installed on MAZs, KamAZs, MTZs and other unpretentious "workhorses". In fairness, it should be noted that in recent years, especially with the start of the introduction of European environmental standards of the Euro family, the situation began to change rapidly: many refineries owned by large companies have embarked on technical re-equipment. Naturally, diesel fuel produced by these enterprises meets all modern quality standards, but unfortunately, the share of such fuel on the market is still noticeably small, and in most cases diesel fuel of insufficient quality is offered at gas stations for the safe and long operation of engines developed and manufactured abroad. But we don't have any other fuel yet. And the only way out is the use of special fuel additives that can “pull up” the indicators to the required values. But it is worth remembering that it is categorically not recommended to use additives from different manufacturers at the same time, because. they may turn out to be incompatible and instead of improving the properties of the fuel, it is quite possible to bring closer the need for a visit to the minder and to a specialized workshop for injection pumps and fuel systems. Moreover, the leading manufacturers of auto chemical goods have additives in their assortment for almost any occasion.
A good example is the world's leading manufacturer of automotive chemicals, the German company LIQUI MOLY and its line of fuel additives for diesel engines.
LIQUI MOLY Diesel Spülung
DESCRIPTION: Diesel-Spülung is a combination of highly effective cleaning additives. Special substances perfectly clean fuel system, prevent corrosion and improve the quality of diesel fuel (cetane number).
PROPERTIES:
Cleans the fuel system
Removes carbon deposits and deposits from injectors
Increases the cetane number of diesel fuel
Prevents souring of needles
Protects against corrosion
Provides optimal combustion of fuel
Improves vehicle performance, power and throttle response
APPLICATION AREA:
For all types of diesel engines with starting problems, erratic engine operation, clogged injectors and needles. To eliminate these problems, 500 ml of the additive is sufficient.
APPLICATION:
Preventive use: Must be added to the fuel approximately every 3000 km per 75 liters
Cleaning the fuel system: Disconnect the fuel line from the tank and the fuel return hose and place them in a can of additive. Start the engine and let it run on the additive periodically by gasping until all the additive is used up.
An alternative use of the additive is possible with the JetClean. To do this, pour 2-3 liters of additive into the device, connect all the necessary adapters and clean the engine according to the instructions attached to the device.
LIQUI MOLY Speed Diesel Zusatz
DESCRIPTION: Speed Diesel Zusatz additive for diesel is a combination of active substances with cleaning, dispersing and protective properties, taking into account modern engines, fuels and lubricants and operating conditions.
PROPERTIES:
Provides optimum combustion and as a result small beats. fuel consumption
Increases power and economy
Protects fuel pump, injector needles, cylinder/piston area and exhaust valves
Easy start in winter without warming up
Gentle combustion process
AREAS OF USE:
Diesel fuel additive for all diesel engines in cars, trucks, tractors, buses, agricultural vehicles and stationary engines. It can be excellently used for the conservation of engines during long periods of inactivity under extreme conditions.
APPLICATION:
A volume of 1 liter is sufficient for 400 liters of diesel fuel.
Measuring cup 25 ml (integrated in the lid) for 10 liters of diesel fuel.
Mixing with fuel is carried out automatically.
LIQUI MOLY Super Diesel Additive
DESCRIPTION: Super Diesel Additiv is a combination of active ingredients with cleaning, dispersing and protective properties. Designed for modern engines, fuels and lubricants and operating conditions, increasing the cetane number. The contained Lubricity Improver gives low sulfur diesel fuel sufficient lubricity. Due to the increased flammability of the fuel in the cold state, it burns better and, as a result, exhaust gases are reduced.
PROPERTIES:
Provides cleanliness and prevents deposits in the fuel system and combustion chamber
Keeps injection nozzles clean, ensures optimal combustion in the engine, which leads to low specific fuel consumption and maximum engine power
Prevents sticking and gumming of nozzle needles
Increases the lubricating effect of low sulfur diesel fuel (low sulfur diesel according to DIN EN 590) and protects the fuel distributor pump from wear.
Increases the cetane number of diesel fuel, and softens the combustion process
Contains antioxidant and prevents corrosion
Compatible with all modern diesel oxidation catalysts.
AREAS OF USE:
Diesel fuel additive for all diesel engines as well as high pressure diesel engines in cars, trucks, tractors, construction machines and stationary engines. It can be excellently used for the conservation of engines during long periods of inactivity under extreme conditions.
LIQUI MOLY Speed Tec Diesel
DESCRIPTION: Speed Tec Diesel is a modern fuel additive designed to improve combustion and acceleration in the partial load range. The product is compatible with all conventional diesel fuels and additives of any quality. Significantly increases vehicle acceleration.
PROPERTIES:
No organometallic compounds
Higher power output
Best driving performance
Does not affect cetane number
Improves vehicle acceleration
Cleans the intake system
Catalyst Compatible
FIELD OF APPLICATION: Additive is intended for all types of diesel engines. For improved acceleration and increased ride comfort.
APPLICATION:
Add additive to the fuel at the rate of 250 ml package for a maximum of 70 liters of fuel.
LIQUI MOLY DIESEL-SCHMIER-ADDITIV
DESCRIPTION:
A combination of surfactants that improves the lubricity of diesel fuel. The product meets the requirements of diesel engine manufacturers that require operation on environmentally friendly fuels with a low sulfur content. Protects fuel equipment from increased wear and premature failure. Designed specifically for monoblock high pressure fuel pumps in passenger cars and light trucks.
CHARACTERISTICS:
Reduces wear on the high pressure fuel pump
Protects the fuel system from corrosion
Prevents pressure drop in the fuel system
Reduces operating noise and pump vibration
Suitable for all modern vehicles with catalytic converters
Economical to use, does not pollute the environment
APPLICATION AREA:
It is added to diesel fuel for all diesel engines with conventional injection pumps to reduce friction and wear of fuel system parts.
APPLICATION
With regular use improves the lubricating properties of diesel fuel. One 150 gram bottle is enough for 80 liters of diesel fuel. Mixing happens on its own. To apply constantly, at each gas station. When the engine is temporarily out of operation or canned, add 1% of the product to diesel fuel.
LIQUI MOLY Systempflege Diesel
DESCRIPTION:
Combination of active substances with high lubricating properties and cleaning additives. The product meets the requirements of diesel engines with a low sulfur content to protect them from obsolescence. Due to the increased readiness for ignition, better combustion of the fuel is ensured and the release of toxic substances into the atmosphere is reduced.
PROPERTIES:
Provides cleanliness and protects against deposits in the fuel system and fuel combustion areas;
Keeps nozzles clean, helping to improve fuel combustion and thus reducing the amount of fuel consumed;
Reduces nozzle fouling;
Contains antioxidant and protects against corrosion;
Suitable for all modern diesel oxide catalysts.
APPLICATION AREA:
Addition to diesel fuel in all diesel engines with Common-Rail injection system. Great for "preserving" engines in extreme weather conditions
APPLICATION:
Improves ignition readiness and, with regular use, improves the lubricating properties of diesel fuel with a low sulfur content. One 250 gram bottle is enough for 75 liters of diesel fuel. Dosage 1:300. Apply every 2000 km. When the engine is temporarily out of operation or canned, add 1% of the product to diesel fuel. The product can be applied at any time as the mixing takes place on its own.