inputEngine oil marking. How to create a lubricant for a motor What is synthetic oil made of
Have power plant in any car, almost all components and mechanisms interact with each other. This interaction is accompanied by the emergence of a frictional force between the moving parts of the mechanisms. Moreover, due to the high loading of some mechanisms, the friction force between the rubbing surfaces is quite high. In order to minimize the friction force between engine elements, lubricants are used - motor oils.
The task of these materials is to create a thin film between the rubbing surfaces to prevent the metal elements of assemblies and mechanisms from contacting. The film is especially needed on the two main mechanisms of the engine - the crank-connecting rod and the gas distribution. In addition to reducing friction, it also performs a cooling function, partially removing heat from the surfaces of the units. Also, the task is to wash the rubbing surfaces to remove dirt particles.
But not all motor oils used in cars are the same. Only its composition is similar. It, by whatever method is obtained, includes an oil base and a set of various additives. Next, we will take a closer look at everything related to motor oils.
Engine oil composition, classification
So, all engine oils are primarily divided according to the chemical composition of the base, that is, by what method and from what it is obtained.
According to this criterion, they are all divided into three categories - mineral, synthetic and semi-synthetic.
The base, or base, for mineral oils is taken from crude oil. To obtain a lubricant, oil is filtered by selective cleaning and dewaxed. These oils were the first to be used in cars. However, now they are used less and less, since in their properties they are inferior to the other two.
The first synthetic bases were obtained by chemical synthesis. Since its production by chemical means is rather complicated, its cost was much higher than the mineral one. The essence of this method comes down to the synthesis of certain chemical substances of the base of the oil from the molecules. The complexity of obtaining a base lies in the need to select molecules from the simplest hydrocarbons with the same parameters and properties for further synthesis of base molecules from them.
Now the category of synthetic lubricants also includes mixtures obtained from a synthetic base with the addition of a mineral component, or obtained by hydrocracking. But in this case, it is no longer completely synthetic.
The last category is semi-synthetic oils. They received this name due to the fact that they include both mineral and synthetic oil in their composition. In fact, a semi-synthetic is a mixture of two oils, and the proportions of the components may differ.
- Basic, obtained by refining and dewaxing oil;
- Basic, with a high degree of purification by hydrotreating (mineral improved purification);
- Basic, obtained by hydrocracking, which provides a viscosity index from 80 to 120;
- Basic, obtained by hydrocracking with a viscosity index above 120;
- Base derived from polyalphaolefins (synthetic oils);
- Basic, not included in the above categories (Esters, glycols, etc.);
Groups of additives used
And this is just the classification of the base of the motor oil. It also contains additives. They provide a range of improved oil performance. Without them, the base inside the power unit will not work for a long time, since its operating conditions often change, which leads to its rapid destruction.
As for additives, they are divided into three groups, each of which is aimed at performing certain functions.
Shell oil production
The group of functional additives is considered the most extensive. Additives of this group provide a large number of positive properties, for example, additives of this group provide an increased antiwear effect, antioxidant effect, prevent the formation of foam, protect against corrosion.
The second group, no less important, is viscous additives. The task of these additives is to increase the viscosity index of the oil and maintain its certain value at different temperature conditions.
The third group of additives is to increase fluidity.
The percentage of additives in engine oil may vary. In some types, additives make up 5% of the total, but there are also oils in which additives make up 25%.
SAE classification
There are several classifications of engine oils, each of which is responsible for specific properties. The most common classification is SAE. This classification was developed by the Association of Automotive Engineers. It characterizes the viscosity, as well as the properties of "sticking" it to the surface of the part. Essentially, viscosity is the property of an oil to "stick" to a metal surface while remaining fluid. It must retain these properties under certain temperature conditions.
According to this classification, oils are divided into summer, winter and all-season. Moreover, summer and winter species are subdivided into several types, but all-season ones are not subdivided according to this principle.
In total, according to this classification, 6 types of winter and 6 types of summer oils are produced. As for the winter one, its designation consists of an alphanumeric index, and only a digital index is used to designate the summer one.
The gradation of winter oil starts from 0 to 25, while the designation of the next type is carried out in 5 units, that is, 0, 5, 10 and so on up to 25. The letter W - Winter is an additional designation for winter oil. The smaller the digital designation, the lower its viscosity at low temperatures. So, 0W winter oil will ensure the start of the power plant even at temperatures below -30 C, since the viscosity even at this temperature will not be very high. But 25W oil can be used at temperatures not lower than -10 C.
Daylight saving works the other way around. The graduation of summer oil is from 10 to 60, and the value of the subsequent type is 10 units more, and the letter designation is not used.
So, oil with the designation 20 will retain its viscosity at temperatures up to +20, and the designation 50 indicates the retention of viscosity at temperatures up to +50 and above.
But we have not received separate distribution of winter and summer oils due to a rather wide temperature range throughout the year. The change of seasons would lead to at least two changes in it a year.
All-season types of oil have become more widespread in our country. This type of viscosity is indicated for both low and high temperatures, and both winter and summer viscosity designations appear in their designation, for example, 5W-40. But at the same time, the viscosity indicators of 5W-40 may differ from the indicators taken separately for winter 5W and summer 40 oils.
But as such, there are no types of all-season oils, they are produced with designations from 0W-50 to 25W-20.
It should be borne in mind that the temperature indicator of the use of this or that oil is approximate and is only recommended by manufacturers. Real temperature readings depend on many factors, including the design features of the engine.
Often, car owners stop only at this classification, considering that knowledge of the temperature regime and viscosity is quite enough.
ACEA classification
However, there are other equally important classifications. There is also a classification developed by the Association of European Car Manufacturers. This classification is designated ACEA.
This classification is reduced to the possibility of using oils on certain engines. In total, it includes 4 classes: A - for gasoline power plants, B - for diesel engines used in passenger cars, as well as trucks with low carrying capacity. There is another class - E, which includes high-power diesel engines installed on large trucks.
It should be noted that this classification also takes into account the produced energy-saving oils. Their feature is a reduced viscosity at high engine operating temperatures than standard ones. Due to this, the slip resistance between the engine elements is also reduced, this has a positive effect on power losses due to friction in the power unit during operation. However, the increased fluidity of this oil leads to the fact that the film on the surface is thinner than when using standard oil, respectively, the wear rate of engine elements is higher, therefore, it is not suitable for all units.
To designate standard and energy-saving oil, in addition to the letter index, a digital is also used. There are five digital indices in total - from 1 to 5.
Energy-saving lubricants in this classification received indexes 1 and 5, and indexes 2,3 and 4 denote standard oils. Moreover, these indices are applicable to both gasoline and to. And energy-saving materials according to ACEA are designated A1, A5, as well as B1 and B5. All other designations refer to standard materials. There is no such type designation for class E.
API classification
The Americans have about the same classification, but more extensive. Developed by the American Petroleum Institute, its initials are API.
API classifies oils by general performance properties. The essence of this classification is reduced to its applicability on engines of different years of production. This classification was introduced only because over time, power plants have improved, the requirements for lubricants and their additives have increased. Also, this classification takes into account design features engines.
As in the ACEA classification, oils are classified according to their applicability on engines - gasoline and diesel. But the designation of applicability to a particular engine is different: gasoline - S, diesel - S.
Also, this classification provides for the letter designation of the classes of characteristics and properties of the lubricant.
The API classification for includes 12 classes of lubricants, divided by their application in engines. Brief characteristics of these classes are shown in the table:
| API classification of oils for gasoline engines | |
|---|---|
| SA | For power units used without special loads |
| SB | For power plants used with medium loads |
| SC | For engines used with increased loads (used on cars up to 67 years old) |
| SD | For medium-boost motors used with high loads (used on cars up to 71 onwards) |
| SE | For power units of high force used with high loads (used on cars up to 79 onwards) |
| SF | For high-boost power plants used with high loads using unleaded gasoline, without the use of turbocharging (used on cars up to 88 onwards) |
| SG | For engines with high boost, using unleaded gasoline, using turbocharging (used on cars up to 93 onwards) |
| SH | For engines with high boost, using turbocharging (used on cars up to 96 onwards) |
| SJ | For all power plants (used on cars up to 96 onwards). It is a replacement for all of the above classes. |
| SL | For all power units (used on cars up to 2004 onwards) |
| SM | For all engines (used on cars currently produced) |
| EC | Energy-saving lubricants |
There is approximately the same table for diesel engines, it also consists of 12 classes:
| API classification of diesel oils | |
|---|---|
| CB | For power plants used at high loads, medium boost, without turbocharging (used on cars up to 60 onwards) |
| CC | For power units used at increased loads, high boost, without the use of turbocharging, as well as with it (used on cars from 61 onwards) |
| CD | For engines used at increased loads, high boost, without turbocharging, as well as with it (used on cars from 55 onwards) |
| CD + | Class for Japanese cars, with improved parameters |
| CD-II | For two-stroke power units (used on vehicles from 87 onwards) |
| CE | For engines used at increased loads, high boost, without the use of turbocharging, as well as with it (introduced to replace CC and CD classes. Used on vehicles from 87 onwards) |
| CF | For engines of off-road vehicles equipped with distributed injection (Applied on vehicles from 94 onwards) |
| CF-2 | For two-stroke power units (introduced to replace the CD-II class) |
| CF-4 | For high-speed engines using turbocharging (used on cars from 90 onwards) |
| CG-4 | For engines used in severe conditions (introduced to replace CD, CE, CF-4 classes. Applies to cars from 95 onwards) |
| CH-4 | For high-speed power units (used on cars from 98 onwards) |
| CI-4 | For high-speed power plants (used on cars since 2002) |
It should be noted that some types of oils are produced that can be applied in the same way on both a gasoline engine and a diesel engine. In such lubricants, the API classification designation includes a double designation, for example, API SL / CH-4.
The association also developed a separate API classification for lubricants intended for two-stroke power plants, as well as a classification for transmission oils.
There are other specifications as well:
Alternative method of obtaining oil
It should be noted that developments in the creation of new motor oils are ongoing. Prospective at the moment is the production of oil, or rather the basis for it, from natural gas. This technology is now being actively developed by Shell.
To obtain the base, natural gas (methane) goes through several stages. First, it is mixed with oxygen to produce a synthesis gas consisting of hydrogen and carbon monoxide.
Then, hydrocarbons are isolated from this synthesis gas with the help of catalysts, but already in a liquid state. The resulting liquid is subjected to hydrocracking to separate its fraction. One of these fractions is the oil base.
To obtain a finished product, it remains only to add the required additive package.
AutoleekMany years ago, in 1873, Professor John Ellis was able to obtain motor oil for the first time. He spent a lot of time studying the characteristics of crude oil. Numerous experiments led him to conclude that it has excellent lubricating characteristics.
By adding the manufactured lubricant to the valve train of steam engines, he noticed that valve movement was much smoother. The wear of parts has decreased, the operating time of the power plant has increased. John registered his discovery and opened the world's first production of motor lubricants.
Manufacturing technology
It all starts with the extraction of crude oil. It is filtered, where it is cleaned of harmful components. All operations are carried out at specialized enterprises with the appropriate equipment. Motor oils are divided into several types, each of which differs in components and properties.
Mineral ones are considered the cheapest. They are made from oil that is filtered and standardized. Synthetic are the most expensive class. They are based on substances obtained after complex chemical manipulations with products from gas and oil. The hybrid of the above-described compositions came to be called semisynthetics.
How motor oil is made: the manufacturing process
The modern process for the manufacture of lubricants for the latest technology is subdivided into several stages. First, the preparation of raw materials is carried out, from which certain oil fractions are obtained. To obtain components of motor oils, special technological units are used that process oil in accordance with flow schemes.
After distillation of oil, distillate oil fractions are obtained:
- 350-420 degrees;
- 420-500 degrees;
- More than 500C.
The modern oil refining industry opens up new possibilities for distillation using the minimum fractional composition. The result is a lot more base oils.
At the next stage, all fractions are purified in special oil block plants. Moreover, cleaning can be performed in various ways. Selective purification of the existing oil fractions is mainly carried out. To do this, use:
- A mixture of tricresol with phenol;
- Deasphalted, which is part of propane.
The result is a residual oil fraction raffinate. Its hydrotreating is carried out in a permanent catalyst. Residual raffinate is produced at temperatures above 500 ° C. At the final stage, commercial oils are obtained by compounding oil components and special additives.
More and more high-end cars appear on the roads every day. Of course, engine oil manufacturers take this factor into account. Each car manufacturer creates a specific technical task for the manufacture of the latest lubricant corresponding to the characteristics of the car engine. It must reliably protect the propulsion system and extend its service life.
Of course, the technology described above is generalized. Every lubricant manufacturer tries to keep the technology of obtaining the latest oil secret. This is the only way to stay afloat in an age of tough competition.
2013-11-01 17:56
I must say that there is an opinion among motorists that when mixing different types, the oil curls up and acquires a gel-like consistency. To say unequivocally that this is so is not true, but I will say right away that it is not desirable to do so.
Although semi-synthetic oil is obtained by mixing synthetics and mineral water, in this case nothing happens. But it must be remembered that when obtaining a semi-synthetic oil, oil bases are mixed before adding additives, therefore, most likely, there is nothing unusual and does not happen.
But with a high degree of probability, it can happen that when mixing engine oils from different manufacturers, the chemical additives in the composition can enter into a chemical reaction with each other and cause harm to your engine.
Therefore, if you are going to add another type of oil to the engine, try to have the old and new oils from the same manufacturer. Do not forget that when you change the oil, 5% of the old oil remains in the engine. If you are going to change the oil manufacturer, or fill the engine with oil that is different in type from the old one, I advise you to flush the engine.
Engine oil viscosity
The main task for the viscosity parameter is to reduce the frictional force of all parts of the operating engine, and especially the pistons in the cylinder, which, in addition to all this, must have maximum tightness.
If we also recall the operating temperature range of engine oil, which reaches up to 150 degrees (not to be confused with the temperature of antifreeze, which is shown on the dashboard), then it becomes clear that to create an engine oil that had the same parameters at such different temperatures is simply impossible.
That is why each engine manufacturer determines for its products some optimal, average parameter for the requirements for engine oil, in order to achieve the maximum engine life with minimal wear of parts inside.
The classification of engine oils by viscosity is most often called " SAE classification ", which was developed by the engineers of the American Automobile Association. SAE parameter describes oil viscosity state at different temperature conditions.
In a word, the SAE parameter is the maximum and minimum temperature within which the engine operation can be considered reliable and safe.
On engine oil labels, viscosity is written as follows: - for example SAE 5W-30.
Let's see what these numbers and the letter W. mean. W is the first letter from the English word "winter" - "winter". This oil can be used in winter.
The number 5, in our example, defines the minimum engine start temperature. To determine, it is necessary to subtract the number written before the letter W from the number 40, in our case it is number 5. For oil with the viscosity parameter AE 5W-30, the lower temperature limit is -35 degrees.
Digit 30 defines the upper temperature limit, and it is not determined directly. That is, if it says 30, this does not mean at all that the oil can be used at a temperature of +30 degrees. This parameter indicates the minimum and maximum viscosity of the oil in a running engine - the higher this figure, the thicker the engine oil.
To make it clearer, we publish some viscosity parameters with indicated temperature boundaries.
0W-30 - lower limit -35 degrees Celsius, upper +25 degrees Celsius
5W-40 - from -30 to +40
10W-50 - from -25 to +50
15W-60 - from -20 to +50 and above
Additive set
API classification - American Petroleum Institute (American Fuel Institute) in 1969 created a system of classifications for the quality of engine oils.
This parameter defines the type of engine, petrol or diesel.
The API class in labels looks like this: SJ API , API CF-4 , API SJ / CF-4 ... If there is no description for the API classification on the engine oil container, then the API certificate for this type of oil has not been assigned.
Now let's decipher the letters and numbers. The first letter always characterizes the type of oil: S for gasoline and C for diesel engines.
There are motor oils that are designed for both diesel and gasoline engines. In such cases, the API classification of both types is put on the label, which are separated by the / (slash) symbol.
API SJ / CF-4 can be deciphered as follows: oil can be used both in gasoline and diesel engines, however, since the first in the code is written SJ, that is, the letter S, this means that gasoline engines are more preferable.
ACEA classification - European version of the API classification... Created in 1995. Subsequent changes to this standard were made in 2002 and 2004.
All manufacturers who use on their label aCEA classification standard , it is imperative to check the oil in accordance with the standards European Engine Lubricant Quality Management System .
EELQMS is the company responsible for ensuring that motor oils meet ACEA requirements.
In 2004, according to the ACEA standard, all types of motor oils are divided into 3 categories.
The first category is designated by the letters A / B. This includes all types of engine oils (before that they were divided: class A - for gasoline engines and class B - for diesel engines) for diesel and gasoline engines that were produced before 2004.
Oils in this category are designated in 4 classes - A1 / B1-04, A3 / B3-04, A3 / B4-04, A5 / B5-04. In this article, we will not describe in detail the decoding of these letters and numbers, we just note that the higher the numbers, the better the engine oil.
The second category is a new class and is marked as the letter C. Designation on the labels C1-04, C2-04, C3-04. These oils comply with Euro-4 environmental standards. Oils classified by this standard are of much higher quality and high-tech, designed for gasoline and diesel engines.
The third category in the European classification is designated by the letter E. In the oil labels it looks like - E4 and E5. In 2004, two new classes E6 and E7 were added. Designed for heavy vehicles (diesel engines only).
I think that so much information will be sufficient for an independent and correct choice of engine oil. Now let's sum up the results with specific tips for choosing an engine oil.
So that the choice of engine oil is not mistaken, once again carefully look at the photos with tables on the classification of engine oils that are presented in this publication (click on the pictures and they will increase in size, it will be easier to read what has been written).
If you have a new car, be sure to try to get the oil where you bought the car. This is probably the most the best way the choice of engine oil for new cars, which are under warranty.
Look in the manual for your car from the manufacturer, if there is one. According to the idea, it should contain the parameters of the engine oil for your engine.
If you bought a car by hand, try to find out more information about the oil in the engine. In the absence of such information, the oil change must be done with the engine flushing.
Keep in mind that every time you change the brand of engine oil, you harm your engine, unless of course this is justified by specific facts. And the specific reason for changing the brand of oil is only an overestimated consumption, or a leak.
In such cases, if the car has a high mileage, it will be better if you switch to a thicker, viscous engine oil. Switch from synthetic oil to semi-synthetics.
And if your car is almost new, then in such cases, most likely you will have to replace some oil seals, or gaskets in the engine.
To clarify the viscosity of the oil, pay attention to the mileage of your vehicle. High mileage requires a high high-temperature viscosity of the engine oil (this is the number after the letter W in the classification code). Remember the history of my car, which I wrote about at the beginning of this article.
Usually, the service interval (the mileage after which the oil in the engine should be changed) is determined by the engine manufacturer, however, experienced motorists are guided by other signs.
It is clear to everyone that the more often the oil is changed, the better for the engine. But, we must not forget that good oils are expensive. That is why it is worthwhile to correctly determine when it is necessary to change the oil.
On average, the mileage after which the oil is changed for modern cars ranges from 5 to 8 thousand kilometers. But if you usually drive at low speeds, do not load the engine, then this figure can increase to 10-12 thousand kilometers.
Personally, I am determined by the color and viscosity of the oil when the engine is running. If the color of the oil is kept in light shades, then there is no need for replacement yet. Using a dipstick (the engine should be at operating temperature), drip a drop of oil from the engine onto your finger, and rub it with a second finger. You should feel like your fingers are sliding apart. This is normal. And if you feel small solid particles between your fingers, or your fingers stick and there is a strong feeling of friction, then the filter and oil must be replaced.
The service interval is also strongly influenced by the quality of the fuel. Low-quality fuel causes non-combustible liquid fuel components to enter the oil and reduce the viscosity of the engine oil.
Dear motorists, visitors to my site!
A big request in the comments to describe the signs that force you to change the engine oil.
18.01.2013
Engine oils: composition, classifications, test methods, approvals
1. Composition of engine oils
Motor oils are complex blends that can best be characterized as compounds made up of base oils and additives. Compared to other groups of lubricants, base oils play a very important role. Without going into the characteristics and details of the production of the composition, we can say that the base oils are selected in such a way that they fundamentally correspond to the classification in terms of viscosity and functional characteristics. The end products are marketed as semi-synthetic (hydrocracked oils) or synthetic motor oils based on mineral oils.
The exact international nomenclature divides base oils into six groups:
... Group 1. Soluble low-viscosity oils containing saturated hydrocarbons< 90%, 80 < ИВ < 120, содержание S > 0,03%.
... Group 2. Hydrocracking oils with a saturated hydrocarbon content\u003e 90%, 80< ИВ < 120, содержание S < 0,03%.
... Group 3. Hydrocracking oils with a saturated hydrocarbon content\u003e 90%, VI\u003e 120, S content< 0,03%.
... Group 4. PJSC.
... Group 5. Esters and others.
... Group 6. Products of oligomerization of olefins with internal double bonds.
1.1. Additives
Depending on the base oil used and the required engine characteristics, engine oils can contain up to 30 different additives, the percentage of which can vary from 5 to 25% in total. In the production of base oils, a distinction is made between functional, viscosity and fluidity additives. Typically, functional additives are the largest group.
1.2. Functional additives
The following chemicals are tabulated under the general title "Functional Additives" (Table 1).
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Typically, the categories of substances listed above have more than one function. This is true for engine oils. Zinc dialkyldithiophosphates, for example, are mainly antiwear additives and also have an antioxidant effect due to their specific degradation mechanism. In addition, complex compositions of individual components typically exhibit synergistic and antagonistic interactions that must be tailored to a particular application. The composition of the base oil components further influences these specific interactions. Therefore, to create an optimal engine oil composition requires a lot of experience and new developments.
1.3. Viscous additives
Viscous additives can be divided into two groups: non-polar, non-dispersive and polar, dispersant. In principle, the first group is only necessary to establish the viscosity of multigrade oils. Viscosity additives increase oil viscosity and viscosity index by changing their solubility at different temperatures. Depending on the chemical structure and solubility in the base oil, at an absolute concentration of 0.2 to 1.0%, they can increase the viscosity by 50-200%. Through special modification, viscous dispersants are often used as ashless dispersants with additional thickening effects. In addition, viscosity and depressant additives affect the viscosity of the compounds at low temperatures (measured as pour point, using CCS and MRV) and have a strong influence on the viscosity at high temperatures and high shear rates. At the moment, in the United States, such additional requirements are put forward for low-temperature stability (certain values \u200b\u200bof the gelation index), which are unattainable without viscosity and depressant additives correctly selected for the base oil.
2. Characterization and testing
To achieve clarity in the classifications and specifications of engine oils by viscosity, we will consider in detail the methods of their testing.
2.1. Physical and chemical test methods
The physicochemical properties of engine oil are usually assessed using standard laboratory methods. This assessment mainly focuses on the rheological test values \u200b\u200band the previously reviewed classification system. SAE.
Various viscosity test methods are used to accurately determine low and high temperature viscosity. The viscosity determined in this way is characteristic of the engine oil in a particular state of the engine. At low temperatures (from -10 to -40 ° C), to determine the apparent viscosity, use MRV mini-rotational viscometer) with a low shear gradient; thus, the fluidity of the oil in the area of \u200b\u200bthe oil pump is determined. In addition, the maximum viscosity as a threshold is determined in five graduated steps. Dynamic CCS (cold cranking simulator) the viscosity, which is determined at temperatures from -10 to -40 ° C with a high shear gradient, is also the apparent viscosity, reflecting the tribological conditions on crankshaft during a cold start of the engine. The maximum values \u200b\u200binherent in SAE J300, ensure reliable oil circulation during the start-up phase.
Dynamic viscosity at a temperature of 150 ° C and a shear rate of 10 6 s -1, i.e. high temperature and high shear rate ( HTHS), describes the rheological characteristics at high thermal loads that occur when operating with full throttle opening. Corresponding threshold values \u200b\u200balso guarantee a lubricating film that meets all requirements even under these conditions.
In addition to rheological performance, PLA testing, volatility testing of engine oils and additives, as well as foaming and deaeration tendencies can be characterized using simple methods. In addition, the seal compatibility of high alloy oils is tested on standard reference elastomers by static swelling test methods followed by elongation.
2.2. Motor tests
Since checking engine oils through long-term performance tests alone does not provide a realistic possibility of assessing their quality, a number of international committees have established test methods in certain experimental engines operating under reproducible and practically relevant conditions. In Europe, the testing, approval and standardization of oils is responsible for SEC (Coordinating European Council for the development and testing of lubricants and fuels). Requirements ACEA (European Association of Automotive Designers) performance specifications are set in the form of sequential oil test methods developed in collaboration with additives and lubricant manufacturers. In the United States, the automotive industry and the American Petroleum Institute (API) perform this task. This institute develops test methods and limit values. Asian Committee ILSAC mainly adopts American specifications for automotive lubricants.
In principle, test methods focus on the following general evaluation criteria:
... oxidation and thermal stability;
... dispersion of soot and sludge particles;
... protection against wear and corrosion;
... resistance to foaming and shear.
Specifications for test methods for engine oils have been developed differentially for gasoline and diesel engines of cars and trucks, and each tested engine is characterized by one or a group of criteria. Table Tables 2 and 3 show the relevant criteria for gasoline and diesel engines.
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2.3. Motor oils for passenger cars
Passenger car engines include all gasoline and light diesel engines with direct or indirect injection. To meet the minimum requirements imposed on them, oils must pass the tests on the above engines, regardless of the viscosity grade and base oil. For gasoline engines, tests for the oxidative stability of the oil are carried out in the engine Sequence III F (T max \u003d 149 ° C) and in the engine Peugeot J P... Along with the increase in viscosity (KB 40) associated with oxidation, the piston deposits and the aging-induced cleanliness of the piston ring grooves are evaluated. Three other standardized methods have been developed for assessing sludge production. It is a measure of the oil's ability to effectively disperse oil-insoluble aging residues that form during fuel combustion. Insoluble and inadequately dispersed solids result in a sticky, pasty oil sludge that can block oil passages and filters, thereby compromising engine lubrication. In accordance with M 2H SL and M111SL such sludge must be visually assessed in the oil sump, crankcase and oil passages, and by measuring the pressure drop across the filters. If European test methods M 271 SL and M 111 SL are carried out in "hot" mode, that is, at high loads and speeds, with fuel sensitive to nitrooxidation, then the method Sequence VGin North America mainly focuses on low temperature engine operating conditions leading to so-called "cold" black sludge. Engine Peugeot TU3 is used to monitor critical valve actuator wear that can affect engine ignition timing. After a live load test program, cam scoring and pitting on valve lifters are evaluated.
Testing on light diesel engines is an exclusively European method, as such engines are becoming more and more popular in Europe. The first place is again occupied by the determination of oxidative stability and the dispersion of soot specific to diesel engines. With increasing injection pressure, the formation of soot increased, and the viscosity of the oil increased by almost 500%, and the combustion temperature also increased. These criteria, as well as their effect on exhaust gases, are tested on the engine. VW 1.6 l with intercooler and Peugeot xud 11 (viscosity increase). Side effects of cylinder and cam wear and polishing of the inner surface of the cylinder liner should also be avoided, as this can cause honing. The test program also included a so-called multipurpose test engine. OM 02 AND.
In 2003, the program for the development of oils for diesel engines OM611 DE 22 LAhas been complemented by an important additional multipurpose test method. This method is applicable to modern low-sulfur diesel fuels, which form up to 8% soot in the engine after a 300-hour run. These conditions require engine oils with extremely good dispersing properties with respect to soot to eliminate the possibility of high viscosity increases and wear. The new special test methods for automakers have stringent criteria for extending oil change times and conserving fuel. Setting such conflicting goals as viscosity reduction and greater reliability, on the other hand, is a major challenge for engine oil manufacturers.
2. 4. Motor oils for commercial automotive vehicles
Commercial vehicle vehicles include trucks, buses, tractors, combine harvesters, construction and stationary equipment with diesel engines. Along with prechamber diesel engines, which are mainly replaced by direct injection engines in Europe, most of them are equipped with high turbochargers. The economic and environmental aspects associated with high fuel injection pressures have contributed to improved fuel combustion and therefore lower emissions. On the initiative ACEAnd the terms for changing the oil were increased to 10 thousand km for long-distance transportation. The fundamental differences between diesel and gasoline engines are discussed in detail below.
Durability and reliability are the benchmarks for evaluating the commercial automotive sector. Very heavy duty oils ( HD) must meet these requirements. The dominant requirements are the ability to disperse high concentrations of carbon deposits and neutralize sulfuric by-products of combustion. The characteristics of oils are also assessed by piston cleanliness, wear and polish of the inner surface of the cylinder. Oxidation and carbon deposits, which occur mainly in the upper piston ring groove, lead to poor piston condition and increased wear. This, in turn, results in abrasion of the models (honing patterns) in the cylinders, a problem better known as polishing the inner surface of the cylinder liner. This results in increased oil consumption and poor piston lubrication because the oil cannot be trapped by the honing rings. Inadequate dispersion of carbon and sludge as well as chemical corrosion can lead to premature bearing wear. Finally, the advanced turbocharged diesel engines should also be appreciated. Breakthrough gases typically carry some oil mist into the exhaust, and turbochargers are very sensitive to unstable components. HD oils.
In general, in HD you can find all categories of oils, and they are arranged in increasing severity of operating conditions:
... heavy duty oils ( HD);
... oils for very heavy (harsh) working conditions (SHPD);
... oils for extremely (extremely) severe working conditions ( XHPD).
Despite numerous attempts to use proven test methods to obtain the necessary information, 4- and 6-cylinder engines are now being used to test the main performance characteristics of engine oils in 400-hour tests, which replaced the original on single-cylinder test engines ( MWMB: PetterAWB).
In addition to the aforementioned multipurpose test engines OM 602 and OM 611, European specifications require mandatory engine tests Daimler — Chrysler ОМ 364 LA or OM 441 LA... Both test methods apply only to XHPDoils (with oil change after 100 thousand km of run). The tests determine and evaluate the cleanliness of the pistons, the wear of the cylinders and the polish of the cylinder liner. Especially in OM441 LAwhere deposits on the turbocharging system are registered, as well as an increase in pressure. The soot-induced oil thickening criterion is assessed by the method ASTM (on the engine Mack T8)
Regardless of the viscosity grade and the base oil used, classic HD oils have a large reserve of alkalinity and, therefore, a high content of salts of alkaline earth metals and organic acids. As for ashless dispersants, oils are designed to disperse soot (carbon deposits). In order to avoid the formation of additional deposits in the oil, as a rule, special viscous additives are introduced.
Fleet maintenance oils face particular challenges. Unlike specialized products, oils have to simultaneously satisfy many "whims" of cars and trucks. High concentrations of highly alkaline soaps have to be sacrificed to keep pistons clean because gasoline engines tend to ignite spontaneously in the presence of high concentrations of metal-containing detergents. Therefore, other components must be selected, for example, the skillful use of unconventional base oils along with detergents, dispersants, viscosity index improvers and antioxidants.
3. Classification of engine oils according to specifications
As previously mentioned, physical and chemical properties are not enough when choosing the best engine oil. Complex and expensive hands-on and bench motor tests are performed to assess and understand the performance
3.1. Military specifications
Pioneered by the US military, these specifications specify the minimum requirements for engine oils used in military vehicles. Military specifications are based on certain physical and chemical data and some standard motor test methods. In the past, these specifications were also used in the civilian sector to determine the quality of motor oils, but in recent years have almost disappeared from the German market. Specifications from MIL-L-46152AND before MIL-L-46152 is now canceled. Engine oils meeting these specifications are suitable for use in American gasoline and diesel engines. MIL-L-46152E(canceled in 1991) corresponds to API SG / CC. MIL-L-2I04 C classifies motor oils with a high additive content for gasoline and diesel engines with normal intake and turbocharging. MIL-L-2I04 D overlaps MIL-L-2104C and requires additional testing in a 2-stroke diesel engine Detroit with high inflation. In addition, the requirements of the specifications must be met Caterpillar TO and Allison C-3. MIL-L-2104E similar in content MIL-L-2104C... Gasoline engine tests have been revised to include stricter test methods ( Seg111 E / Seg. VE).
3.2. Classification API and ILSAC
APItogether with ASTM and SAE developed a classification in which motor oils are sorted in accordance with the requirements imposed on them, taking into account the designs of existing engines (Table 4). The oils are subject to standard engine tests. API distinguishes a class of motor oils for gasoline engines operating in light conditions ( S - service oils), and for diesel engines ( С - commercial, commercial vehicles). So far, diesel engines in passenger cars do not outnumber gasoline ones, but in recent years they have been gaining momentum and demand for them in the United States is constantly growing. In addition, a number of advantages associated with fuel economy have been identified ( The EU - energy saving).
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3.3. SSMS specifications
Insofar as API and MIL specifications tested only on powerful, low-speed engines V8 USA and the requirements of European engines (low power, high-speed) were met only inadequately, SEC (The European Coordinating Council for the Development of Performance Tests for Lubricating Oils and Motor Fuels) together with CCMC (Common Market Automobile Manufacturers Committee) developed a number of test methods that used European engines to test engine oils (Table 5). These test methods and methods APIcreate the basis for the development of new motor oils. In 1996, SSMS were replaced by ACEAand ceased to exist.
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3.4. ACEA specifications
As a result of insurmountable differences, the SSMS was disbanded, and in its place was formed ACEA (Association of European Automobile Manufacturers). The first ACEA the classifications entered into force on 1 January 1996, and the SSMS specifications remained in effect only in the interim.
Specifications ACEA were revised in 1996, replaced in 1998 and entered into force on 1 March. Additional foam tests were introduced for all categories, and elastomer tests were modified.
Categories "A" belonged to gasoline, " B"- to diesel engines of passenger cars, and" E»- for diesel engines operating in difficult conditions.
On September 1, 1999, the 1998 specifications were replaced and remained in effect until February 1, 2004. The categories were revised E2, EZ and E4 for heavy duty diesel oils and a new category introduced E5: it reflected the new specific requirements for oils for Euro 3 engines and the often higher carbon content in such oils. "A" and "5" remained identical with the 1998 version.
Test methods for oils were published on February 1, 2002 ACEA 2002 (sequence) instead of sequence 1999, and they remained in effect until November 1, 2006. Cleanliness and sludge requirements for gasoline engines were revised and introduced ( Al, AND2 and A3) and a new category AND5 with engine characteristics A3, but with higher fuel economy requirements. Improvements have been made to test methods for cleanliness, wear, sludge control for light diesel vehicles and a new category 55 has been added with superior cleanliness and improved fuel economy. Particular emphasis is placed on antiwear performance in relation to rings, cylinder liners and bearings for oils of category E5.
Since November 1, 2004 test methods ACEA 2004 apply and may be referenced by trade organizations. Oils of these categories are compatible with all other categories (Table 6).
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Categories "A" and "B" are now combined and can only be advertised together. New categories introduced C1, FROM2 and FROM3, which relate to engine oils for passenger cars equipped with exhaust gas aftertreatment systems, for example, filters to capture particulate matter from the exhaust gases of diesel engines ( DPF). These oils are characterized by a particularly low ash content and low levels of sulfur and phosphorus to minimize the negative impact on filter systems and catalysts.
4. Approval of motor oils for passenger cars by manufacturers
Along with the specifications already listed, some manufacturers have their own specifications and require engine oils to be tested on their own engines (Table 7).
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European ACEA, North American EMA (Engine Builders Association) and Japanese JAMA(Japan Automobile Manufacturers Association) are working on specifications for a global classification system with sustainable performance. First specification of this kind DHD-1 (heavy duty diesel engine) was published in early 2001. The test consists of a combination of motor and bench tests from CH API- and ACEA E3/E5 to Japanese DX-1 categories. In 2002, categories were established for diesel engines operating in light conditions ( DLD) (Table 8).
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Roman Maslov.
Based on materials from foreign publications.
Uninterrupted operation of the engine is a guarantee of a long service life of any car. Any malfunction of the engine can lead to long and, more importantly, costly repairs. Therefore, it is so important to timely and correctly service the engine and monitor the wear of its parts, since wear of parts is one of the most frequent causes of breakdowns. Untimely oil change can subsequently lead to serious breakdowns and unnecessary wear of engine parts, not to mention an increase in fuel consumption. Such a seemingly simple step - timely replacement and correct selection of oil, significantly increases the service life of any engine.
It can be classified according to the main characteristics:
- field of application of the oil (intended for gasoline or diesel engines or universal),
- viscosity (classification by oil viscosity (taking into account the change in oil viscosity with changes in ambient temperature); distinguish between all-season (most popular in the CIS and Europe), winter and summer oils),
- type (determined depending on the production method and feedstock; distinguish between mineral, semi-synthetic and synthetic oils).
Classification by oil type
Mineral oils are composed of a mixture of different hydrocarbons.
Mineral motor oils are produced from heavy high-boiling oil fractions.
To improve the quality of mineral oil, it is subjected to a special treatment for molecular restructuring (called hydrocracking) at high temperature and high pressure with the addition of catalysts and hydrogen. This process is being improved all the time, and modern mineral oils are of significantly higher quality compared to their predecessors, produced 10 and more years ago.
Synthetic oils are produced by chemical synthesis. Synthetic oils differ from mineral oils in higher homogeneity and increased stability.
as an example, consider the effect of temperature on the properties of mineral and synthetic oils
Mineral oils are subject to high temperatures and require the use of special additives, but this leads to a shorter oil life and, as a result, more frequent oil changes. Synthetic oils are less dependent on temperatures and allow you to maintain sufficient density and viscosity both at low temperatures and at elevated temperatures, which reduces wear of parts and, in general, provides fuel economy.
It is necessary to replace synthetic oils less often, however, the price of such oils is often an order of magnitude higher compared to other types of motor oils due to the high cost of raw materials and equipment used for production.
Despite all the advantages of using synthetic oils, they cannot be used for all engines.
For example, for old cars (with engines with stuffing box packing), the use of such oil is unacceptable.
There is also a third (intermediate) type - semi-synthetic motor oils, obtained by mixing mineral and synthetic oils. Such oils are better than mineral oils in their technical characteristics (higher viscosity index, less susceptibility to the formation of deposits during operation at high temperatures, etc.). Semi-synthetic oils provide better engine protection (in comparison with pure mineral oil) and reduce fuel consumption (by 3-5% on average). The price of semi-synthetic oils is lower than synthetic oils, which makes them very popular among consumers.
engine oil additives
The high requirements for the quality of the lubricating characteristics of engine oil have led to the emergence of a huge number of additives that are added to the oil to improve its properties.
Often, an oil can contain several types of additives at once, each of which affects a specific property of the oil.
For example, the addition of a "detergent" additive prevents parts from sticking, in particular, piston rings, etc., and also cleans and reduces deposits on the parts of an oil film, the so-called "varnish", an antiwear additive reduces wear of rubbing parts, forming a stable oil film on the friction surface.
Depending on the goals and needs of the engine, you can select the optimal engine oil with the required properties due to the optimally selected combination of additives.
In today's market, customers are offered many different additives and additives that can be added to engine oil. However, you should be extremely careful with such additives, since by improving one property of an engine oil, we can significantly degrade another. For example, adding a detergent additive to clean the engine, we can worsen the antiwear properties of the oil and, as a result, provoke unnecessary wear of engine components.
Engine oil viscosity classification
Determined according to SAE methodology of the Society of Automotive Engineers of America.
SAE markings consist of letters and numbers or only numbers.
Let's consider how to decipher this marking and what viscosity oil to choose for your car.
Summer grades of engine oil contain only numbers in the viscosity label (20, 30, 40, 50 and 60). The letter W (from the English words Winter - winter) - denotes a winter grade of oil. The SAE J300 standard lists 6 viscosity grades for winter oils (OW, 5W, 10W, 15W, 20W, 25W).
It should be noted that the freezing point of mineral oils is an order of magnitude higher compared to synthetic oils and this should be taken into account when choosing an oil in regions with severe winters.
For example, in regions where winter temperatures can drop below -30 ° C, it is recommended to use synthetic or at least semi-synthetic oil to prevent it from freezing.
Some synthetic oils can start the engine even at -40 ° C, since their freezing point is below -50 ° C, while mineral oil thickens strongly and can completely freeze even at -30-35 ° C.
Most average drivers change their oil on average once a year, so multi-grade motor oils are most popular and common in countries with temperate climates and relatively small seasonal temperature fluctuations.
All-season oil marking contains both winter and summer viscosity, which are usually indicated with a dash, hyphen or space (for example, SAE 10W30, SAE 15W-40, etc.).
It is worth noting that synthetic oils are more fluid, they are easier to distribute throughout the oil system and can more easily penetrate gaps and not tight enough joints, and it is easiest to detect oil leakage when using synthetic oil.
For example, oil seal leakage, which many attribute to the excessive aggressiveness of the oil, often signals the wear of the lip of the cuff and the need to replace it.
When using mineral or semi-synthetic oils, it is worthwhile to carefully examine the engine elements for wear and tightness of the joints.
Classification by levels of performance properties and conditions of oil use
In addition to the viscosity and type of oil, there is also a classification according to the levels of performance properties and conditions of oil use.
This classification was proposed by API (American Petroleum Institute - American Petroleum Institute) in 1947.
Having undergone several changes and additions, this classification is used to this day.
According to this classification, oils are divided into 2 categories: "S" (Service) and "C" (Commercial).
Oils marked S are used for four-stroke gasoline engines, and oils marked C are used for agricultural machinery, road construction equipment and other large vehicles.
Category "S" is divided into several classes according to the increasing requirements for oil quality characteristics: API SA, API SB, API SC, API SD, API SE, API SF, API SG, API SH and API SJ, API SL, API SM. To date, not all of the listed categories are used, some of them have already been recognized as obsolete and are no longer used.
In particular, the following classes of category "S" are no longer used:
- SA (oils without additional additives, suitable for use in gasoline and diesel engines),
- SG (for gasoline engines manufactured in the late 80s - early 90s),
- SB (oils with light antioxidant and antiwear protection for low-power gasoline engines),
- SF (for gasoline engines produced in the 80s),
- SC (for old-style gasoline and diesel engines that were produced back in the 60s),
- SE (for use in gasoline engines of 72-79 years, additionally contain additives against carbon deposits, corrosion and oxidation),
- SD (for gasoline engines in passenger cars of the late 60s).
Also now there are two more relatively new classes of oils for modern cars - SL and SM.
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