Classification of motor oils. Specification of motor oils according to API Classification of motor oils according to ilsac table

API (American Petroleum Institute) system for classifying motor oils by application and performance properties. The specification divides everything motor oils into two categories: S - oils for gasoline and C - for diesel engines. Each class is assigned a letter in alphabetical order starting with A: API SA, SB, SC, SD, SE, SF, SG, SH, SJ... It’s the same with category C. What you need to remember when choosing an oil based on the API classification is that the higher the class, the more modern the oil and suitable for your engine. For example, if the manual states class SJ, then the class will definitely suit your car S.M. accepted later, but in this case it is impossible to use oil corresponding to the class SH previously accepted by your class S.M..

Universal oils for gasoline and diesel engines have designations of both categories, for example API SG/CD, SJ/CF.

Classes of diesel oils are further subdivided for two-stroke (CD-2, CF-2) and four-stroke diesel engines (CF-4, CG-4, CH-4).

API categories: SA, SB, SC, SD, SE, SF, SG, CA, CB, CC, CD, CE, CF- today they are outdated, but in some countries oils of these categories are still produced; the API SH category is “conditionally valid” and can only be used as an additional one, for example API CG-4/SH.

ASTM D 4485"Standard Performance Specification for Performance of Engine Oils"

SAE J183 APR96"Quality of performance properties of motor oils and engine operational classifications (with the exception of energy-saving oils)" (Engine Oil Performance and Engine Service Classifications (Other than "Energy Conserving").

Changing engine oil is a procedure that the driver can perform independently. To do this, it is enough to find an overpass, after which the work will take a maximum of half an hour. But before you do the work of changing the oil, you need to purchase it. When choosing consumable fluids, you should always follow the manufacturers' recommendations. But if there are specific requirements for the oil, or if you cannot find the required composition in the store, you can independently understand the oil labeling to choose the best option.

What are the types of motor oils?

As you know, the main task of motor oil is to minimize friction of moving parts in a car engine. The less parts rub, the less likely it is to break, which means the engine will last longer.

Depending on which engine is used in the car, there are 3 types of motor oils: gasoline, diesel and universal. As can be understood from their names, the first two are designed for specific types of engines, and the universal option is suitable for both diesel and gasoline engines.

In addition to dividing oils by engine type, they can also be classified by seasonality, when it is recommended to use such formulations. The oil can be summer, winter or all-season. It is worth noting that the seasonality of the oil depends on its viscosity, as well as on the rate of change in consistency with increasing or decreasing temperature.

IN winter period It is better to use less viscous oils to make it easier for the engine to start after parking in the cold. In summer, such oils are not recommended, since they do not lubricate engine components well enough. More viscous options are suitable for summer, but if used in winter, they can prevent the engine from starting quickly when negative temperature environment.

Please note: The most common now are all-season motor oils, the viscosity of which practically does not change with ambient temperature.

What are motor oils made of?

Each motor oil manufacturer has its own unique formulation, which, in its opinion and tests, is the ideal combination between cost and protective functions performed. However, the basis for all motor oils is the same - these are oil fractions that were obtained during oil refining.

Please note: Recently, some manufacturers have begun to use oil fractions obtained artificially.

Motor oils can be divided into 3 types based on composition: mineral, synthetic and semi-synthetic.

Manufacturers modern cars It is recommended to use synthetic or semi-synthetic oils. Mineral compounds are currently used, for the most part, for trucks or older models of passenger cars.

Important: If the canister of motor oil does not indicate that it is synthetic or semi-synthetic, most likely the composition is mineral.

When choosing the type of oil for your car, be sure to read the manufacturer’s recommendation. Synthetic oil is not always suitable for engines that were initially designed to use a mineral composition.

Basic properties and parameters of motor oils

As noted above, each manufacturer keeps the exact composition of their motor oils secret because they use their own unique sets of additives. But the main viscosity parameter must be indicated when labeling motor oil.

Engine oil viscosity

When choosing a suitable composition, you need to pay attention, first of all, to the viscosity of the oil. It directly determines how much the parts will be damaged during operation:

• High viscosity. Excessively high viscosity makes it difficult for the engine to start at low ambient temperatures. In addition, at high viscosity, “ oil starvation”, since the oil composition will not reach the rubbing parts immediately after starting the engine;
• Low viscosity. It can also lead to damage to rubbing parts due to insufficient pressure in the lubrication system.

Additional additives

Each motor oil that can be found on sale has its own unique set of additives that complement its performance properties. Depending on the condition of the engine, its tendency to wear out, as well as other parameters, the car owner can choose the oil he needs. Some of the properties that are added with additive kits are:

• Additional wear protection;
• Minimizing the likelihood of chips and various foreign substances being deposited in the motor;
• Resistance to corrosion;
• The presence of additional antioxidant properties;
• Additional “cleaning” additives.

This list is far from complete. On the canister of each motor oil you can see the main advantages that make it stand out in terms of performance.

Motor oil markings

In Russia, motor oil, regardless of where it is produced, may contain certification marks according to the following standards: SAE, ILSAC, ACEA, API.

This is determined by GOST 17479.1-85. Decoding the labeling of automobile motor oils according to the specified GOST is carried out as follows:

• Kinematic viscosity of motor oil. Indicated by a number. Depending on the viscosity, the oil is classified as summer, winter or year-round (all-season). Numbers from 6 to 16 (even numbers only), as well as 20 and 24 are summer oil values. Winter roads are numbers from 3 to 6. If the oil can be used in both seasons, the summer and winter class is indicated through the line;
• Application area. By this parameter compositions are divided into 6 categories, which are designated by Russian letters from A to E;
• Engine's type. If the index is set to 1, this indicates that the oil is produced for gasoline engines, if 2, it is for diesel engines. If the index is not set, then the oil is universal.

Let's take a detailed look at the international standards for labeling motor oils, which are recognized in Russia.

Explanation of SAE marking

The oil viscosity index is classified by the international standard SAE (Society of Automotive Engineers). This classification has been compiled for more than 100 years, when for the first time drivers and car manufacturers faced the question of choosing and creating a suitable oil for engines.

According to the SAE standard, each motor oil has certain properties at low and high ambient temperatures. Depending on the conditions in which the car will be operated, you need to choose an oil of suitable viscosity.

The SAE standard marking is easy to read:

• If the marking contains the letter W, this indicates that the oil is winter grade;
• If the marking contains only a number, this indicates that the oil is summer. Moreover, the higher the number, the higher the viscosity. Number variation - from 0 to 50;
• If the marking contains a number with W and a separate number, this indicates that the oil is all-season.

Decoding API markings

The API mark was developed by the American Petroleum Institute. It should be read as follows:

• If after the API indication there is an EC notation, this indicates that the oil is energy-saving;
• The indicated numbers (Roman) after the abbreviation indicate the degree of economy of the fuel used by the car;
• If the letter S is present, it means that the oil is suitable for gasoline engines, while the letter C indicates that the oil is designed for diesel engines. If the oil is universal, then both letters are indicated;
• The level of performance properties is also indicated by a letter - from A to L. The closer the letter is to the beginning of the alphabet, the lower the level of performance properties;
• Diesel oils can be double and quadruple. They correspond to the numbers 2 or 4 at the end of the marking.

Decoding the ACEA oil classification

This marking was developed in Europe by the Automobile Manufacturers Association. It includes the largest companies: Volvo, BMW, Ford, Porsche and dozens of others.

The ACEA classification divides oils into 3 categories as follows:

• A/B. Oils developed for gasoline and diesel engines;
• C. Oils that are designed for diesel and gasoline engines, but are also more environmentally friendly - meet the Euro-4 exhaust gas standard. Such motor oils can be used in conjunction with a catalyst and particulate filters;
• E. Motor oils for heavy duty diesel vehicles.

Each category includes several classes, that is, you can find categories A1/B1, A3/B3, C1, C2, C3 and so on. The larger the number after the letters, the better the performance properties of the oil. However, the number of classes may increase over time if the association decides to introduce a new class.

Decoding of ILSAC oil classification

Japanese and American automobile manufacturers jointly developed the ILSAC classification. It is used most often in the production of consumable fluids for Japanese cars.

Together with the SAE classification of the oil, which characterizes its viscosity, the API determines its applicability to a specific engine. You can read what the API itself is and what other classifications there are.
For most modern gasoline engines, it is recommended to use oil of the SL quality group if the engine was produced before 2004 or SM if after. In some places, if the year of manufacture is before 2001, SJ oil is allowed.
The reference books say the following:
“SJ - Oils for engines produced in 1996-2001. They contain fewer environmentally harmful impurities than SH group oils and have energy-saving properties.
SL – Oils for engines produced since 2001. They have significantly improved detergent, antioxidant, anti-wear and energy-saving properties, reduced volatility and good compatibility with exhaust gas catalysts.
SM – Oils for engines produced since 2004. Oils in this category meet the increased requirements of manufacturers of new generation engines. Replace oils of SJ and SL groups.”
There is a new SN oil, but there is little information about it yet. It is clear that SN group oils can be considered the best today. And they are capable of replacing everything that was produced before. That is, if the car's instructions allow SJ oil, then SN is also suitable for it.
For comparison, the most common and popular groups SL and SM were selected
So, what would you like to have in an ideal oil? Firstly, it must ideally and optimally lubricate the parts, and in all engine operating modes. This means reducing friction as much as possible, thereby increasing power and reducing fuel consumption. Secondly, minimize wear, thereby extending the life of the motor. Thirdly, to serve as long as possible, reducing the cost of replacing it. Fourthly, reduce environmental damage from the engine; in the civilized world this point is considered very important.
It’s good to have some harmony in the price-quality ratio.

OIL AGING

There are several reasons and factors for oil aging. Oil is a complex combination of hydrocarbon compounds, with various additives and inclusions called an additive package. In the combustion chamber, the oil film remaining after the piston moves to bottom dead center takes on the full power of the heat flow, which gradually changes the structure and composition of the oil. After all, only a small part of this film burns out, and the rest, overheated, with volatilized light hydrocarbons, oxidized by contact with oxygen at high temperature, is washed into the engine sump. There is not much of this modified oil per cycle - the film thickness is micron, but there are a lot of cycles. There is no such heating in the bearings, maximum up to 180 degrees, but the pressures are very high, reaching 30...40 MPa. This also leads to a change in the properties of the oil. In addition, in the oil pan it comes into contact with crankcase gases, which are hot and aggressive.
Oil must wash the engine - it does wash it, but at the same time it is saturated with contaminants, both mechanical and organic. Some of them will sit in oil filter, but something will remain in the oil volume. And, in addition, at the same time, detergent components, an important part of the additive package, are activated.
For modern “synthetics”, the stated resources are large - 20...30 thousand kilometers.

Tests on an aged engine

The more oil is supplied to the cylinders, the faster it ages. Thicker oil films on the cylinder walls mean that more oil is exposed to heat during each cycle. And its volume in the crankcase is constantly decreasing - due to large waste. The increased pressure of crankcase gases and their higher temperature also increases the rate of oil oxidation. And the sharply increasing amount of deposits in an old engine requires more detergent additives.
Therefore, it is logical to speed up oil testing on an artificially aged engine. For testing, a special engine was assembled, with normal bearing clearances and sharply increased clearances in the cylinder-piston group.

SL, SM

Modern “synthetics”, identical according to SAE, 5W40, were selected for testing.
Now let's try to look for different oils according to API classification. It would be correct if all oils were of the same brand, but of different API groups. But, alas, this does not happen - the oil is more High Quality in all firms it simply displaces its predecessor. Therefore, you will have to choose from what is available. But, to increase the reliability of the results, two oils were included in each comparison group.
The first sample is Esso Ultron oil (1,100 rubles per canister), which has a transitional quality class of SJ/SL. The second is BP Visco 5000 oil (1070 rubles per canister). From the SM family - French Motul X-Clean 8100 (2810 rubles per canister). As a pair, they took a completely new Dutch oil NGN Gold (1030 rubles per canister).
After each test cycle, the motors were disassembled, measured, and parts were weighed to determine wear and the degree of contamination.
After that, tests were carried out on a motor assembled taking into account all the requirements for clearances, practically new, unworn, and well-run in. Standard test cycles were run on it sequentially, first for all fresh oils, then for those “killed” by the resource cycle. And already here they measured power, fuel consumption, and environmental parameters.
The first cycle of tests - on fresh oils - did not reveal any particular difference in the engine response to the API group - everything remained within the measurement error.
And the second cycle, using used oils, put everything in its place. Synthetic oils the SL groups sharply decreased their performance compared to their fresh samples, while the Motul and NGN Gold decreased to a significantly lesser extent. The difference between oils of different categories was already much more noticeable - up to 6...7% in fuel consumption, up to 10% in toxicity, and 2...4% in power between the Esso-Visco and Motul-NGN groups. Moreover, the engine responded more than others to the aging of BP Visco oil.
The test results are summarized in the table:

This is how the operating high-temperature kinematic viscosity of oils of different API groups changes. First - a decrease, this is the destruction of thickening additives. And then - growth. This is a consequence of decomposition and changes in properties base oil. The less pronounced this process is, the longer the oil resource.

In terms of viscosity, all oils clearly correspond to the range prescribed by the SAE 5W40 class. Viscosity indices are very high, characteristic of good “synthetics” (“viscosity index” is a parameter indirectly responsible for cold engine starts).
Look at the content of the active elements. This is a direct characteristic of the additive package. What is striking here is that their concentrations in the original oils of both the SL and SM groups are very close. Indeed, the vast majority of manufacturers use almost the same additive packages - there are only a few manufacturers of them in the world. But the base of all oils is different, and the numbers differ.
Sulfur content. Sulfur compounds hit catalysts hard. It is always present in the oil - both from base oil and as part of extreme pressure and anti-wear additives. Motul X-Clean oil turned out to be the leader in terms of oil purity from sulfur, and NGN Gold was the “leader” at the other end. But there are no regulatory restrictions on this parameter, and experience suggests that for most oils it is higher than 0.5...0.6% sulfur content.
Base number. For all oils it is quite high - this is a sign of cleaning ability. But SM, Motul X-Clean, and NGN Gold oils are lower. The more stable base of SM oils requires fewer detergent additives to maintain the required engine cleanliness, and excess alkali in the oil is harmful - it increases corrosion activity and reduces the service life of additives.
Analysis of the data obtained on used oils confirmed that, indeed, oils of the SM group are more stable. And this means their service life is longer.
Let's return to the motor test data. Everything is confirmed by the results in “physical chemistry”. Indeed, Motul X-Clean and NGN Gold gave a greater energy-saving effect - the engine, albeit a little, became more economical, a little more powerful, and this effect persists and even grows with parallel operation. But the main thing is that these oils produced noticeably less deposits in the engine itself, in the oil pan, on the valve mechanism, and on the pistons (and this is the most important thing). And wear of parts is also less, and significantly. And this is again confirmed by “physical chemistry” - see the content of wear products.
IS IT WORTH PAYING THE EXTRA? So, the bottom line. Do I need to overpay for modern SM oils? For those who have a direct reference to SM oils in their instructions, this question has a clear answer. The rest have a choice.
Of course, SL class oils are also high quality, but SM actually have certain “advantages”. This provides better protection of the motor from wear, a lower level of deposits in the motor, and a longer service life.
The specific figure after which mileage it is necessary to change oils of one and another class is a purely individual parameter that depends on both the brand of the engine and its technical condition, and the quality of the fuel used, and the driving style. But according to estimates, good SM group oils will give SL oils a 30...40 percent head start in terms of service life.

Opening the engine and weighing the parts after testing each oil made it possible to evaluate their protective capabilities. SM group oils really reduce wear more effectively - this was confirmed by our experiment

Table 1 PHYSICAL AND CHEMICAL INDICATORS OF MOTOR OIL SAMPLES

The numerator contains the indicators determined in the initial oil samples after the first test cycle (after 6 operating hours), the denominator – in the final samples (after 120 operating hours)

AVERAGED ENGINE PERFORMANCE OBTAINED WHEN OPERATING WITH VARIOUS MOTOR OILS

The numerator contains indicators determined for fresh oil, the denominator - for final oil samples (after 120 operating hours)
Deterioration in indicators is highlighted in red, improvement in green, and change within the measurement error in blue.

Mass of deposits on control weight elements at the end of the test cycle

Deposits on the side surface of the piston are the most dangerous! They can lead to ring sticking - and hence loss of compression and piston overheating. These are approximately the types of deposits produced by completely killed mineral oils.

And these are SL group oils...

And these are SM groups. The difference is noticeable

There are also deposits in the engine crankcase after SL group oils, their presence is inevitable

This is what the same crankcase looks like after using SM oil

On valve mechanisms the difference is not so noticeable, but it is also there.. This is after the SL oil

This is after the SM group oil

Gasoline engine maintenance classifications

Classifications of diesel engine maintenance

ACEA - specifications of motor oils for gasoline (A), diesel (B) engines passenger cars, as well as engines equipped with an exhaust gas neutralization system (C).

- A1/B1: motor oils for gasoline and diesel engines with a lower friction coefficient and low viscosity.HTHS( stability of the viscosity characteristics of the oil under extreme conditions, at very high temperatures) viscosity from 2.6 to 3.5 MPa.
- A3/B3: low-viscosity motor oils for gasoline and diesel engines with extended oil change intervals for year-round use.HTHS viscosity ≥ 3.5 MPa. Exceeds A1/B1 and A2/B2 regarding piston cleanliness and oxidation resistance.
- A3/B4: motor oils for gasoline and diesel engines with direct injection.Higher requirements for direct injection diesel engines (designated B4). HTHS viscosity ≥ 3.5 MPa.
- A5/B5: Motor oils for high-performance gasoline and diesel engines with oil change intervals. Designed for oils with low friction coefficient and low viscosity. HTHS ≥ 2.9.

-C1 : High performance motor oils for use in vehicles with petrol and diesel engines equipped particulate filter. With a low coefficient of friction, low viscosity, belonging to the Low SAPS standard (sulphated ash, phosphorus, sulfur) and with an HTHS of 2.9 mPa.

- C2: High performance motor oils for use in vehicles with petrol and diesel engines equipped with a particulate filter. Low friction, low viscosity and HTHS 2.9 mPa.These oils help extend catalyst and filter life.

- C3: High performance motor oils for use in vehicles with petrol and diesel engines equipped with a particulate filter.These oils help extend the life of the catalyst and filter.

Specification for diesel truck engines

E4 Recommended for diesel engines that meet Euro I - IV emissions. Operating under very difficult conditions, or with greatly extended oil change intervals. Suitable for engines without particulate filters.
- E6: High-performance motor oils with excellent cleaning properties that prevent wear and soot formation.Recommended for diesel engines that meet Euro I - IV emissions. Operating under very difficult conditions and with greatly extended oil change intervals. They are suitable for engines with and without exhaust gas system. Recommended for engines with diesel particulate filters when using low sulfur fuel (<50).
- E7 : High performance oils with excellent piston cleanliness control.In addition, they must meet the requirements of a high degree of protection against wear, turbocharger deposits and soot formation. Recommended for diesel engines complying with Euro I - IV, operating under very severe conditions, or with greatly extended oil change intervals. E7 oils are recommended for engines without particulate filters, most EGR engines and most engines with SCR NOx systems.
- E9 : Engine oils for engines with/without diesel particulate filters, most EGR engines and most SCR NOx engines.Sulfated ash content max. 1%.