Classification of motor oils

Characteristics of motor oils

The modern motor oil market is very rich. It can be difficult for the average car enthusiast to make the right choice.

To extend the service life of a car engine, as well as its reliable operation, it is necessary to promptly replace the engine oil with fresh one with technical characteristics suitable for the given engine .<\p>

Functions and role of motor oil:

reduces friction between contacting parts and removes heat from them . This significantly increases the service life of the engine;
protects against corrosion;
slows down the formation of deposits on the surface of engine parts, washes away deposits ;
By filling the gaps between the surfaces, the oil reduces the blow-by of gases from the combustion chamber .

Classifications of motor oils

Motor oils are divided by engine type : gasoline and diesel (API classification). There are also oils that are universal in this regard.

Some automobile manufacturers produce oils tested specifically for their engines under the brand of the same name. Purchasing such liquids in most cases allows you to forget about compatibility issues.

However, the majority of oil manufacturers do not test their compatibility with specific engine brands, but simply use generally accepted oil classifications : API, SAE, ACEA, ILSAC.

Let's look at the two main classifications of motor oils and their designations:

Motor oil classification according to SAE

SAE is a classification of motor oils depending on their viscosity in the temperature range from minimum (ambient temperature in winter, before starting the engine) to maximum operating temperature of engine oil in summer.

Developed by the American Society of Automotive Engineers.

Some vehicle operating manuals contain diagrams for selecting oil according to the SAE classification depending on the season and climatic conditions .

Below is a general diagram of the applicability of motor oils within the SAE classification depending on the ambient temperature.

For each specific engine, the optimal values may differ due to the characteristics of its design.

The SAE viscosity grade of an oil is written as one or two numbers, as well as a letter. The presence of the letter W (winter) that separates the two numbers indicates that the oil is all-season. Or, in other words, about the possibility of its use at subzero temperatures .

The first number characterizes the so-called “SAE cold viscosity” .

The lower this number , the lower the temperature it will be possible to start the engine, the less wear on parts as a result of a cold start.

If the ambient temperature is too low, the oil will be too thick and either the starter will not be able to turn the crankshaft, or the thick oil will not be able to properly lubricate all engine parts , including the cylinder head and turbocharger parts.

The second number characterizes the “hot viscosity” .

The fact is that if the hot oil is too liquid, it will simply be squeezed out of the friction pairs . In addition, the film thickness and pressure in the engine lubrication system will decrease. Metal will touch metal. The wear rate will increase significantly. Local overheating will also appear.

To prevent this, the oil must be sufficiently viscous at high temperatures inside the engine. The more viscous the oil, the thicker its film. The thicker the film, the better the parts are protected .

Engines with elevated operating temperatures (some BMW engines and others) are especially sensitive to the amount of “hot viscosity”.

The higher the second number, the higher the temperature the engine oil retains a viscosity sufficient for engine operation.

Please remember that the above table is general. For different engines, the optimal viscosity values may be different. This is due to the fact that starter power, clearances, overall length, lubrication system resistance and operating temperature can vary significantly.

As the internal combustion engine wears out, the gaps in the friction pairs increase . Therefore, it would be advisable to use thicker oils.

Engine oil classification according to API

This specification was created by the American Petroleum Institute. It divides oils by type : gasoline or diesel, as well as by quality and its applicability to a given engine according to a number of parameters : year of manufacture, environmental friendliness, presence of a turbocharger, energy saving and others.

The API oil class is written as two letters, which may be followed by a number.

API has defined standards for three types of oils:

S (Service) - category of oils for gasoline engines. The S is followed by a letter characterizing the version of the specification: with the release of each new set of requirements, the following alphabetical letter is selected: SA (for engines manufactured before 1930), SB (before 1951), ..., SJ (before 2001), SL ( until 2004), SM (until 2010), SN (from 2010 and newer).
C (Commercial) - category of oils for diesel engines. C is followed by a letter characterizing the version of the specification: with the release of each new set of requirements, the next alphabetical letter is selected, and may also be followed by a number characterizing the number of strokes of the engine operating cycle: CA (for engines manufactured before 1950), CB (before 1960), ..., CH-4 (since 1998), CI-4 (since 2002), CJ-4 (since 2006).
EC (Energy Conserving) is a category of energy-saving oils. These oils reduce engine losses caused by oil viscosity. Their use allows to reduce fuel consumption.

In practice, as soon as an oil manufacturer masters a new “quality level” of oil, older versions may disappear from sale. Therefore, in the case of a gasoline engine, you should not try to find oil of the exact API specification that is indicated in the manual for your car. The main thing is to find the same or newer one. To do this, you just need to remember the alphabet.

For example, if a manufacturer recommends API SJ oil, you can also use API SL, SM or SN oils.

With diesels the situation is somewhat more complicated. Newer versions of the oil may cause increased sludge formation . It is recommended to use oil of the exact API classification specified by the manufacturer.

You should also pay attention to the compatibility of the oil with turbocharged engines . For diesel engines it will be CC and later, for gasoline engines - starting with SL.

Next we will discuss the types of motor oils.

Differences between mineral, semi-synthetic and synthetic oils

The very first oils in human history were mineral oils; synthetic and semi-synthetic oils appeared somewhat later.

Mineral automobile oils

Typically, mineral motor oils are the result of distillation of fuel oil. Industrial crops are also used to produce some types of oils.

The low cost of mineral oils is explained by the simple technology of their production. Their advantages include efficiency, stability of action and the absence of destructive effects on the engine and its components.

Oils of this type are practically not used in their pure form , since in this case the lubricating properties appear only at a temperature close to room temperature. You can change the temperature regime using additives. They also help to increase cleaning, anti-wear and anti-corrosion properties.

The disadvantages of mineral oils for internal combustion engines include a significant change in their properties with temperature changes and weak detergent properties, as well as loss of characteristics over time.

In the manufacture of synthetic motor oils, these two disadvantages were taken into account , as a result of which temperature changes do not have such a strong effect on their consistency, and the engine remains clean much longer.

Synthetic automobile oils

Synthetic oils for internal combustion engines are obtained as a result of synthesis. Their properties depend much less on external factors and are characterized by a higher level of stability during operation , including over time.

Benefits of synthetic motor oils:

resistance to temperature changes;
better fluidity in the cold season;
less volatility;
high antifriction properties;
the need for fewer additives, since the main properties are synthesized at the production stage.

Semi-synthetic automobile oils

Semi-synthetic motor oils are a mixture of mineral (50-70%) and synthetic oils . They are characterized by higher efficiency at low temperatures compared to mineral oils.

Semi-synthetic oils are a kind of compromise between mineral and synthetic oils, both in cost and in their properties.

Source: http://alubitel.net/dvigatel/smazka/kharakteristiki-motornykh-masel.html

How are machine oils classified?

Before classifying motor oils, you need to know some concepts on which it depends.

Basic Concepts

Viscosity _ This property is associated with internal friction between layers. As the temperature increases, the viscosity decreases and vice versa.

The operating temperature limits are -35°C - +15-180°C, which causes a change in viscosity several hundred times.

With low viscosity at high temperatures, the strength of the oil film and the pressure in the system will not be enough. As a result, wear of friction pairs increases.

To choose an oil you need to know its main characteristics

Excessively high viscosity at negative temperatures leads to the fact that the starter may not crank the crankshaft and it will become impossible to start the engine. In addition, oil starvation may occur during the first minutes of its operation, since lubricants will not be pumped through the system.

The temperature of the engine oil depends on the air temperature, as well as the design of the internal combustion engine. At a higher temperature, it heats up more, despite the fact that the coolant in the engine is at a certain temperature.

Performance of oils depending on temperature

Motor oil viscosity classes:

Winter lubricants have a low viscosity to ensure cold starting of the engine when the temperature drops. However, they do not provide reliable engine lubrication in summer.
Summer oils, due to their high viscosity, are able to reliably lubricate the engine at high temperatures, but cannot provide a cold start when the ambient temperature is less than 0 degrees.
All-season - when used at low temperatures, they have the viscosity properties of winter lubricants, and when used at high temperatures, they have the properties of summer lubricants.

To obtain similar viscosity-temperature characteristics, low-viscosity motor oils are thickened using special additives that allow them to “thin” less at high temperatures and “thicken” more at low temperatures.

Nowadays, separate winter and summer motor oils have almost been replaced by all-season ones, since there is no need to replace them with the onset of another season. In addition, these may have energy-saving properties.

The operational properties (their level) determine the likely area of application of the motor oil. These include anti-wear, anti-corrosion, detergent-dispersant, antioxidant and other properties.

The type of motor oil depends on the base oil, where additives are added to improve properties.

Base oils include mineral (obtained during oil refining), synthetic (obtained through organic synthesis) and a mixture of them.

In this regard, motor oils are divided into:

mineral (low price with good performance properties, but relatively small temperature range of use),
synthetic (the cost is determined by the complexity of the production processes, but they have better properties due to a slight change in viscosity due to temperature fluctuations),
partially synthetic (a compromise between the first two types with better properties than mineral ones and a lower price than synthetic ones).

Oils are divided into types depending on the production process

SAE classification

SAE classification of motor oils is based on viscosity and temperature dependence over a wide range.

This classification involves dividing motor oils into six winter viscosity classes (0W, 5W, 10W, 15W, 20W, 25W) and 5 summer viscosity classes (20, 30, 40, 50 and 60).

At the same time, winter classes in the designation contain the letter “W” (the first in English Winter). The higher the number included in the designation, the higher the viscosity will be. All-season motor oils are designated by a double number.

Moreover, the first of them determines the minimum viscosity values at negative temperatures and provides starting properties, and the second number indicates the range of viscosity: kinematic at 100 degrees, and dynamic at 150 degrees.

This range is typical for a certain viscosity class of summer lubricant.

The test methods that are included in the analysis of the properties of motor oils according to this classification provide consumers with information about the critical temperature of the oil, when it is possible to crank the engine with a starter, and the motor lubricant is pumped by an oil pump under pressure during a cold start in a mode that does not allow dry friction in the components friction.

SAE oil classification table

Standard performance ranges for commonly used oils

It should be understood that for engines of different designs, the temperature limits of oil performance differ significantly.

This depends on various factors:

starter power,
minimum crankshaft starting speed required to start the engine,
pump performance,
hydraulic resistance of the receiving path oil,
other design, technological and operational factors (technical condition of the car, quality of gasoline, driver qualifications, etc.).

Tips for selecting engine oil by viscosity:

If the car's mileage is less than 25% of the planned resource, then SAE 5W30 or 10W30 oils should be used throughout all seasons.
If the car's mileage is 25-75% with a technically sound engine, then it is recommended to use summer oils SAE 10W40, 15W40, winter oils 5W30 and 10W30 and all-season oils SAE 5W40.
If the car's mileage is more than 75% (old engine), then it is advisable to use summer lubricants SAE 15W40 and 20W40, winter lubricants SAE 5W40 and SAE 10W40, and all-season lubricants SAE 5W40.

Classification by API

The API classification of motor oils is based on the conditions of their use and the level of performance properties. This classification was proposed by the American Petroleum Institute (API) in 1947.

Since that time, it has been supplemented several times, but the principle of division into categories “S” and “C” remains.

Category “S” – oils for four-stroke gasoline engines. It has nine classes in order of increasing levels of performance properties (SA-SJ).

Category “C” is lubricants for diesel engines of vehicles, construction equipment and agricultural machines. Has 10 classes.

Universal oils that are used to lubricate diesel and gasoline engines are double marked.

API oil classification table

ACEA classification

ACEA classification of motor oils is based on European testing methods. It was introduced by the European Automotive Representatives Association (ACEA) in 1996.

According to this classification, oils are divided into three categories:

A1, A2, A3 – oils for gasoline engines;
B1, B2, B3 and B4 – oils for light diesel engines of passenger cars and vans;
E1, E2, E3 and E4 – oils for heavy diesel engines of trucks.

If you want to ask something or find out additional information on this issue, you can always leave a corresponding comment on our website.

The video will help you understand the classification and choose the right oil

Source: http://AvtoMotoSpec.ru/sovety/klassifikaciya-motornyx-masel.html

Standard oil indices

Sergei Iones

Typically, the parameters of the oil recommended for the engine are indicated in the service book or vehicle operating instructions. The choice of oil brand is a subjective decision of each car owner.

Almost always, a wide range of different oils is offered under the manufacturer’s brand. The one that should be poured into your car will have to be determined by the letters and numbers of the oil grade index.

To choose the right oil, you should know that the most important of the many parameters of a motor oil is its viscosity. It changes most strongly depending on the ambient temperature and the temperature of the parts of the running engine that receive oil.

Let me note right away: there are no engine oil temperature indicators on most cars; in the instrument cluster there is only a coolant heating indicator, and drivers take its readings as “engine temperature”.

But the coolant temperature of a warmed-up engine is stable and for almost any engine model it should be about 90 °C. The oil temperature varies significantly under different engine operating conditions and, depending on the speed and intensity of movement, can reach up to 140–150 °C.

The recommended temperature range for use is indicated on the oil packaging.

The current international designation system for motor oils is based on standard indices assigned according to the American SAE and API classifications (for example, SAE 5W40 SL) and the European ACEA quality standard (for example, E6-2005). What does it mean?

The American Association of Automotive Engineers (SAE) has developed a classification of motor oil by viscosity, which describes the viscosity of a particular motor oil at different operating temperatures.

It determines the recommended temperature range in which the oil should operate in the engine.

The API (American Petroleum Institute) and ACEA (European Oil Performance Classification) classifications formulate the minimum basic requirements agreed upon by engine and motor oil manufacturers.

Thick and thin SAE

The SAE abbreviation in the oil labeling is followed by numbers separated by the letter W and a dash, for example, 10W-40. In this case, 10W is an indicator of low-temperature viscosity.

The first number indicates the minimum air temperature at which a cold start of the engine is possible. The number 10 corresponds to a temperature not lower than –30 ° C (40 must be subtracted from the number in front of W).

This is the minimum oil temperature at which the engine oil pump can pump oil through the system without causing dry friction.

If in your region the air temperature in winter rarely drops below –20 °C, then almost any oil sold on the market will suit you. Another question is what condition your starter and battery are in. If they are old, then it will be easier to start the engine at –20 °C with 0W-30 oil than with 15W-40.

The second number after W indicates the high temperature viscosity (in this case it is 40). This is rather a technical parameter - a composite indicator of the level of minimum and maximum oil viscosity at operating temperatures of 100–150 °C.

There is a misconception that high viscosity at high temperatures improves engine performance.

Unjustified use of “tropical” or “sports” oils with high viscosity can lead to loss of power and rapid wear, since the moving engine mechanisms will have to “fight” with too thick oil.

So you should not experiment with oil whose viscosity is not specified by the car manufacturer. And for cars with high mileage and a worn-out engine, which has increased gaps in the joints, it is sometimes reasonable to choose more viscous oils (for example, 10W-40 for winter and 20W-50 for summer).

API by quality

API is often popularly referred to as a classification of the quality of motor oils. First of all, this classification divides motor oils into two types: designed for gasoline and diesel engines. For each of these types, a certain set of properties of motor oils of each class is provided.

On the label, information about the class according to the API system is provided in the following form: API SJ, API CF-4 or API SJ/CF-4. The first letter indicates the type of oil: “S” – gasoline, “C” – diesel.

If a motor oil can be used in both types of engines, then it is assigned both classes - for diesel and gasoline engines. On the oil label, these classes are separated by a fraction, for example, API SJ/CF-4. In this case, the class of oil that is preferable to use is put first.

That is, in this case, the main purpose of the oil is for gasoline engines, but it can also be used in diesel engines.

The second letter means the quality class of the oil. The letters are used in ascending order from the beginning of the Latin alphabet, and the further away the letter is, the higher and more modern class the oil is.

For example, the API SM class appeared on November 30, 2004, and it includes oils for modern gasoline (multi-valve, turbocharged) engines. API SL class is motor oils for engines of cars manufactured after 2000.

They are used in multi-valve, turbocharged engines running on lean fuel mixtures that meet modern environmental and energy saving requirements.

Further, API oil classes are determined by the year of engine production. It is appropriate to make an amendment here that in the US auto industry there is a concept of model year. Therefore, even for European cars, API classes can be determined adjusted for the year of production of a particular engine model, but for engines of Russian brands this system is conditional.

So, API SJ are oils for use in gasoline engines after 1996. API SH class includes motor oils for gasoline engines produced since 1994. This class was adopted in 1992 for oils recommended since 1993.

API class SG – “gasoline” oil for engines manufactured since 1989. For older gasoline engines produced in 1980–1989, API SF class oils are intended for this classification.

And finally, there are even older classes (SA, SB, SC, SD) - these are already oils for oldtimer engines.

Now let's turn to motor oils for diesel engines. API CI-4 class was introduced in 2002. Motor oils corresponding to it are used in modern diesel engines with various types of injection and supercharging.

The emergence of this class is associated with the introduction of new stringent requirements for ecology and exhaust toxicity for engines produced from October 1, 2002. API class CH-4 was introduced on December 1, 1998.

This includes oils designed for four-stroke diesel engines that operate in high-speed modes.

It is useful to look at the CG-4 API class, introduced in 1995. Such motor oils are recommended for four-stroke diesel engines of buses, trucks and tractors of main and non-mainline types, which are operated in high-speed modes and under increased loads.

The specific API class CF-2 (CF-II) was introduced in 1994. This includes motor oils designed for two-stroke diesel engines that are operated in harsh conditions.

The more common API CF-4 class includes motor oils for four-stroke diesel engines produced since 1990.

The main purpose of oils of this class is diesel engines of heavy-duty tractors and cars, which are used for long trips on highways.

ACEA Special Conditions

The new classification of ACEA motor oils can be considered the European analogue of the American API classification. Its most recent edition was adopted in 2004, when motor oils for diesel and gasoline engines of passenger cars according to ACEA were combined into one category.

The letters A/B designate motor oils for gasoline and diesel engines. This category includes all previously developed classes A and B (until 2004, A - motor oils for gasoline engines, B - for diesel engines). Today there are four classes in this category: A1/B1-04, A3/B3-04, A3/B4-04, A5/B5-04.

The letter C designates a new class of oils for diesel and gasoline engines that meet the stricter Euro 4 exhaust gas environmental requirements (as amended in 2005). Such motor oils are compatible with particulate filters. Today there are three classes in this category: C1-04, C2-04, C3-04.

E – motor oils for loaded diesel engines of heavy vehicles. This category has existed since the classification was introduced in 1995. In 2004, two new classes E6 and E7 were added to it and two others, considered obsolete, were excluded.

The API and ACEA classifications formulate the minimum basic requirements for oil.

Moreover, each equipment manufacturer has the right to put forward its own additional requirements for those motor oils that it recommends for the engines of its cars.

Therefore, when deciding what to pour into the engine, first of all carefully study the factory instructions or service book of your car, product catalogs of oil manufacturers and the markings on the canister.

Source: http://www.gruzovikpress.ru/article/8929-klassifikatsiya-motornogo-masla-po-sae-api-i-acea-standartnye-indeksy-masel/

Classification of motor oils - how to determine the type of oil by marking?

The classification of motor oils allows car enthusiasts to understand the issue and choose the optimal type of lubricant for their car, which will ensure long and reliable operation of its engine. All automobile oils are divided into classes according to viscosity and performance properties; we will talk about them further.

Sheinin: “I speak for myself, anyone can cure prostatitis, take the proven Prost...”

The main property of any automobile oil is viscosity, which decreases or increases depending on temperature. As a rule, the operating temperature range for various types is from –40 to +180 degrees.

Insufficient viscosity at high temperatures can lead to rapid destruction of the protective film that forms on the surface of rubbing parts, as well as to a decrease in pressure in the internal combustion engine system.

Conversely, increased viscosity at low temperatures leads to the inability to start the engine or “oil starvation” in the system.

They will protect the chassis and save you money, increasing ground clearance by 3 cm.

Selection of automobile oils

Thus, for the normal functioning of all elements of the internal combustion engine system, the oil is classified by viscosity. Each type of viscosity has recommendations for use in a certain temperature period. Today, all types of motor oils are conventionally divided into three categories:

Winter - have a low viscosity to ensure optimal engine operation in the cold season at low temperatures;
Summer ones - have a high level of viscosity and are recommended for use only at above-zero temperatures;
All-season - the most common and optimal type of motor oils, which provide low viscosity in winter and high viscosity in summer through the use of special synthetic-based additive materials.

Oil additives allow you to change the mineral composition to obtain certain properties. Among the most common additives are detergent-dispersant, anti-corrosion, antioxidant, anti-foam and others.

The need for certain additives depends on certain engine characteristics.

For example, during the operation of a diesel engine, many different deposits are formed, so for this type of engine it is necessary to use automobile oils with detergent-dispersant additives, and turbocharged engines, in turn, require good antioxidant properties from the oil.

The first type has a completely mineral base without additives and is obtained by refining crude oil.

They are characterized by a low price and good performance properties, but their scope of application is limited to the temperature range.

Synthetic or semi-synthetic types are obtained using organic synthesis with the addition of additives; they are higher in price, but have a high operating temperature range.

According to the international standard SAE J300, synthetic or mineral based oils are divided into 6 types of “winter” and 5 types of “summer”. The former are marked with the letter “W” and numbers (SAE 0W–SAE 25W), the latter simply with numbers (SAE 20–SAE 60). All-season ones have double markings, for example, SAE 10W–30 (operating temperature range from –25 to +25 degrees), etc.

Comparison of motor oils

At the same time, the classification of motor oils according to SAE and the association’s recommendations for the use of a certain type of lubricant for certain temperatures may not coincide with the recommendations of a particular car manufacturer.

You should also take into account the features of a specific car model, the degree of boost, the level of thermal stress, the type and quality of fuel used, the presence of turbocharging and other design and technical features of the engine.

That is why each car manufacturer offers its own characteristics and recommendations for the use of oils of different viscosities in a certain temperature period. Such recommendations are usually contained in the technical documentation of the car or in special tables that can be found on the manufacturers’ websites.

With the entry of more advanced, economical and lightweight engines onto the market, oil manufacturers have become increasingly interested in introducing new production technologies using additional additive materials. API classification is usually called “quality classification”, since it allows you to select the optimal material with the required performance characteristics for various types of engines.

Classification of motor oils

According to the API, all motor oils are divided into two categories. The first are designated S - SH, SJ, SL, SM, SN and others - intended for gasoline engines of various types. The second ones are designated by the letter C - CF, CH, CJ and others - intended for diesel engines.

Thus, the first letter indicates the category of oil, the second the level of performance properties, which directly depend on the “proximity” of the letter to the beginning of the alphabet.

For example, type SN has the best level of properties in this line, that is, it has the best anti-foam, anti-oxidation, anti-corrosion and other characteristics.

In addition, the API also distinguishes between universal types of lubricant, which are designated by a double abbreviation, for example, SG/CH, etc. In Europe and the USA, universal types with the prefix EC, which means energy-saving, are very common.

According to the results of various tests, such oils are capable of providing fuel economy in the range of 0.7–0.9 percent. A breakdown of the main types by API can be found in the corresponding tables.

As for versatility, for new gasoline or diesel engines it is better to use oils with high API quality ratings recommended for a specific engine type (diesel or gasoline).

Specialists from ACEA have more stringent requirements for the classification of motor oils. The agency divides all species into three categories (A, B, E) and 12 classes.

The first category contains classes A1-98, A2-96 and A3-98 and is intended for use in gasoline engines.

The second category contains classes from B1-98 to B4-98 and is intended for light diesel engines, and the third category contains classes from E-1 to E-5 for trucks and powerful diesel engines.

Choosing engine oil

Some of the presented classes also have the EC mark, that is, they belong to the energy-saving class.

Such oils not only help save fuel, but also additionally protect the car engine due to additives and HT/HS technology, in which viscosity decreases faster than usual as temperature rises.

This promotes easier movement of parts, which increases their service life and also affects fuel economy.

Such oils are not recommended for use in older cars and in brands for which they were not intended. It is noteworthy that some European manufacturers do not recommend acea class A2, B2, B3, E1 lubricants for use on some of their car models due to, in their opinion, too weak protective properties. Among them are brands such as Mercedes-Benz and Opel.

As mentioned above, the main criterion when choosing oil for your car is the manufacturer’s recommendation. In addition, the choice factor is also influenced by the engine life, that is, the mileage of the car.

For example, for new engines whose service life does not exceed 25%, it is recommended to use a 5W-30 or 10W-30 lubricant according to the SAE classification.

For cars with high mileage, it is recommended to choose oils with maximum ratings, for example, 10W-40 or 20W-40 according to SAE.

Using motor oil

As for performance characteristics, it is not recommended to use oils from different manufacturers at the same time, even if they have identical properties and performance.

If an emergency arises, for example, on the road the indicator shows a critical level of lubrication in the engine, of course, you can add oil from another manufacturer and even a different type.

However, after such mixing, the engine must be flushed with a special flushing fluid, and then new oil must be filled to the required level, following the manufacturer’s recommendations.

If the color of the oil is too dark, this does not mean that it is of poor quality; it may contain a large number of additives, which give it a more saturated color. The same applies to the rapid blackening of the lubricant after a short mileage.

This also does not mean a loss of properties; most likely, it has a large number of detergent additives that can retain combustion products.

In addition, it is not recommended to add additives yourself, as this may lead to the loss of certain properties of the lubricant.

High-quality oil from trusted manufacturers already contains a full range of necessary additives, so it makes no sense to increase their quantity.

It is best to purchase oil from car dealers or official services that work directly with representatives of a particular brand. In this case, the risk of purchasing low-quality products is significantly reduced.

Fake oil under well-known brands, which is plentiful in automobile markets and wholesale warehouses, does not have even half of the properties specified by the “manufacturer”; by pouring it into the engine of your car, you risk reducing the service life and performance of the engine, so you should once again pay attention to the labeling and certification and price.

Source: http://tuningkod.ru/tyuning-avtomobilej/motornye-masla/klassifikaciya-motornyx-masel.html

Composition and classification of motor oil

In the power plant of any car, almost all components and mechanisms interact with each other. This interaction is accompanied by the emergence of a friction force between the moving parts of the mechanisms.

Moreover, due to the high load of some mechanisms, the friction force between the rubbing surfaces is quite high.

To minimize the friction force between engine elements, lubricants are used - motor oils.

The purpose of these materials is to create a thin film between rubbing surfaces to prevent contact between the metal elements of components and mechanisms.

The film is especially needed on two main engine mechanisms - the crank and gas distribution. In addition to reducing friction, it also performs a cooling function, partially removing heat from the surfaces of components.

The task also includes washing rubbing surfaces to remove dirt particles.

But not all motor oils used in cars are the same. Only its composition is similar. It, no matter how it is obtained, includes an oil base and a set of various additives. Next, we’ll take a closer look at everything related to motor oils.

Composition of motor oil, classification

So, all motor oils are first of all divided according to the chemical composition of the base, that is, by what method and from what it was obtained.
According to this criterion, they are all divided into three categories - mineral, synthetic and semi-synthetic.

The base, also known as the base, for mineral oils is taken from crude oil. To obtain a lubricant, oil is filtered using selective purification and also dewaxed. These oils were the first to be used on cars. However, now they are used less and less, since their properties are inferior to the other two.

The first synthetic bases were obtained by chemical synthesis. Since its production by chemical means is quite complex, its cost was significantly higher than that of minerals.

The essence of this method comes down to the synthesis of oil base molecules from certain chemical substances.

The difficulty in obtaining a base lies in the need to select molecules with the same parameters and properties from the simplest hydrocarbons for the 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 contain both mineral and synthetic oil. In fact, semi-synthetic is a mixture of two oils, and the proportions of the components may differ.

These are the main categories of oils that are accepted for general familiarization with the composition. In general, manufacturers divide motor oil bases into 6 categories:

Basic, obtained by purification and dewaxing of oil;
Basic, with a high degree of purification by hydroprocessing (mineral improved purification);
Base, obtained by hydrocracking, which provides a viscosity index from 80 to 120;
Base, obtained by hydrocracking with a viscosity index above 120;
Base, obtained 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 motor oil base. It also contains additives. They provide a number of improved oil properties. 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 specific functions.

Shell oil production

The most extensive group is considered to be functional additives. Additives of this group provide a large number of positive properties, for example, additives of this group provide an increased anti-wear effect, an antioxidant effect, prevent the formation of foam, and protect against corrosion.

The second group, no less important, is viscosity additives. The purpose 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 those that increase fluidity.

The percentage of additives in motor 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 motor oils, and each classification is responsible for certain 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 its “sticking” to the surface of the part. Essentially, viscosity is the property of oil to “stick” to the surface of a metal while remaining fluid.

It must retain these properties at certain temperature conditions.

According to this classification, oils are divided into summer, winter and all-season. Moreover, summer and winter species are divided into several types, but all-season ones are not divided according to this principle.

In total, according to this classification, 6 types of winter and 6 types of summer oil are produced. As for winter, its designation consists of an alphanumeric index, and to designate summer, only a digital index is used.

The gradation of winter oil starts from 0 to 25, while the designation of the subsequent type is carried out through 5 units, that is, 0, 5, 10 and so on up to 25. An additional designation for winter oil is the letter W - Winter.

The smaller the digital designation, the lower its viscosity at low temperatures. Thus, 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.

Summer does the opposite. The gradation of summer oil is carried out from a value of 10 to 60, and the value of the subsequent type is 10 units higher, and the letter designation is not used.

Thus, oil with the designation 20 will retain viscosity at temperatures up to +20, and the designation 50 indicates that the viscosity will be maintained at temperatures up to +50 and above.

But in our country, winter and summer oils are not widely used separately due to the rather wide temperature range throughout the year. The change of seasons would lead to at least two changes in the year.

All-season types of oil are more common in our country. This type of viscosity is indicated for both low and high temperatures, and their designation includes both winter and summer viscosity designations, for example, 5W-40. But at the same time, the viscosity indicators of 5W-40 may differ from those of winter 5W and summer 40 oils taken separately.

But there are no types of all-season oils as such; they are produced with designations from 0W-50 to 25W-20.

It should be borne in mind that the temperature indicator for the use of a particular oil is approximate and is only recommended by manufacturers. Actual temperature indicators depend on many factors, including the design features of the engine.

Often, car owners stop only at this classification, believing that knowledge of temperature conditions and viscosity is quite sufficient.

ACEA classification

However, there are other, no less important classifications. There is also a classification developed by the Association of European Automobile Manufacturers. This classification is designated ACEA.

This classification comes down 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 load capacity. There is another class - E, which includes high-power diesel engines installed on large trucks.

It is worth noting that this classification also takes into account produced energy-saving oils. Their special feature is their reduced viscosity at high engine operating temperatures compared to standard ones.

Due to this, the sliding resistance between engine elements is also reduced, which 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; therefore, the wear rate of engine elements is higher, so it is not suitable for all units.

To designate standard and energy-saving oil, in addition to the letter index, a digital index is also used. There are five digital indices in total – from 1 to 5.

Energy-saving lubricants in this classification received indices 1 and 5, and indices 2,3 and 4 indicate standard oils. Moreover, these indices apply to both gasoline and diesel engines. And energy-saving materials according to ACEA are designated A1, A5, as well as B1 and B5. All other designations refer to standard materials. For class E there is no such type designation.

API classification

The Americans also have approximately the same classification, but more extensive. Classification developed by the American Petroleum Institute, its initials are API.

API categorizes oils based on general performance properties. The essence of this classification comes down to its applicability on engines of different years of production. This classification was introduced only because over time, power plants improved and the requirements for lubricants and their additives increased. This classification also takes into account the design features of engines.

As in the ACEA classification, oils are divided according to their use in engines - gasoline and diesel. But the designation of applicability to a particular engine is different: gasoline - S, diesel - C.

This classification also provides a letter designation for classes of characteristics and properties of the lubricant.

The API classification for gasoline engines includes 12 classes of lubricants, divided by their use in engines. Brief characteristics of these classes are shown in the table:

API classification of oils for gasoline engines

S.A.	For power units used without special loads
S.B.	For power plants used with medium loads
S.C.	For engines used with increased loads (used on cars up to 67 MY)
SD	For medium-boost engines used with high loads (used on cars up to 1971)
S.E.	For high-boost power units used with high loads (used on cars up to 1979)
SF	For high-boost power plants used with high loads using unleaded gasoline, without the use of turbocharging (used on cars up to 88 model year)
S.G.	For high-boost engines, using unleaded gasoline, using turbocharging (used on cars up to 93 model year)
SH	For high-boost engines using turbocharging (used on cars up to 96 onwards)
S.J.	For all power plants (used on cars up to 96). It is a replacement for all of the above classes.
SL	For all power units (used on cars up to 2004)
S.M.	For all engines (applicable to cars currently produced)
E.C.	Energy-saving lubricants

There is approximately the same table for diesel engines, it also consists of 12 classes:

API classification of diesel oils

C.B.	For power plants used at high loads, medium boost, without the use of turbocharging (used on cars up to 60 years of production)
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 the use of 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 equipment since 1987)
C.E.	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 since 1987)
CF	For engines of off-road vehicles equipped with distributed injection (Used on vehicles from 1994 onwards)
CF-2	For two-stroke power units (introduced to replace CD-II class)
CF-4	For high-speed engines using turbocharging (used on cars from 90 onwards)
CG-4	For engines used in harsh conditions (introduced to replace CD, CE, CF-4 classes. Used on 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 used equally on both gasoline and diesel engines. In such lubricants, the API classification designation includes a dual designation, for example, API SL/CH-4.

The association has also developed a separate API classification for lubricants intended for two-stroke power plants, as well as a classification for transmission oils.

There are also other specifications:

ILSAC "International Lubricant Standardization and Approval Committee" is a Japanese association that issues its own standards for oils (GF1, GF2, GF3) used in gasoline engines
OEM is a specification from car manufacturers, they have higher requirements and conduct their own testing, all major companies do this (BMW, MB, Toyota, Honda, MAN, Volvo, Ford and others).

Alternative method for obtaining oil

It should be noted that developments in the creation of new motor oils are ongoing. Promising at the moment is to obtain oil, or rather the base for it, from natural gas. This technology is currently being actively developed by Shell.

To obtain the base, natural gas (methane) goes through several stages. First, it is mixed with oxygen to produce synthesis gas, consisting of hydrogen and carbon monoxide.

Hydrocarbons are then separated from this synthesis gas using catalysts, but in a liquid state. The resulting liquid is subjected to hydrocracking to separate its fraction. One of these fractions is the oil base.