This classification system motor oils was established in 1969 by the American Fuel Institute ( American Petroleum Institute ). Popular classification API also called the quality classification of motor oils.

In particular, this classification divides engine oils into two types: for gasoline and for diesel engines... For each of these types, quality classes are provided, which, in fact, describe a certain set of properties and qualities for motor oils of each class.

On the label, information on the assignment of an API class to an engine oil is provided in the following form: API SJ, API CF-4, or API SJ / CF-4.

It should be noted that the absence on the engine oil label of information on compliance with any of the API classes unambiguously means that this car oil either does not have an API certificate at all, or the quality class assigned to it is hopelessly outdated.

What do the API code symbols mean?

The alphanumeric code is the designation of the oil class. Moreover, the first letter of the coding means the type of oil:

"S" - motor oils for gasoline engines;

"C" - diesel engine oil.

If it can be used in both types of engines, then this oil is assigned two classes - for diesel and for gasoline engines. On the oil label, these classes are separated by a forward slash - for example, API SJ / CF-4. In this case, the first is the class of oil that corresponds to the more preferable (according to the manufacturer of the car oil) application. That is, in the above case, the main purpose of the car oil is for gasoline engines, but at the same time the manufacturer allows its use in diesel engines.

What are the API oil classes and how many are there?

Technology does not stand still, and every year automakers put forward more and more new requirements for motor oils. Therefore, the oil classes are regularly supplemented every few years. At the time of this writing, the following classes existed:

API Engine Oil Grades: Gasoline Engines

API SM class

Motor oils for modern gasoline (multivalve, turbocharged) engines. Compared to the SL class, engine oils that meet API SM requirements must have better protection against oxidation and premature wear of engine parts. In addition, standards have been raised regarding oil properties when low temperatures... Engine oils of this class can be certified according to the ILSAC energy efficiency class

Engine oils that meet the requirements of API SL, SM can be used in cases where the car manufacturer recommends class SJ or earlier.

API SL class

Motor oils for engines of cars manufactured after 2000.

In accordance with the requirements of car manufacturers, motor oils of this class are used in multivalve, turbocharged engines running on lean fuel mixtures that meet modern increased environmental requirements, as well as energy saving.

Automotive oils that meet API SL requirements can be used in cases where the car manufacturer recommends the SJ class or earlier.

SJ API class

Motor oils for use in gasoline engines since 1996.

The SJ API class describes the oils that are used in gasoline engines, starting from 1996 release. Motor oils of this class are intended for use in gasoline engines of passenger cars and sports cars, minibuses and light truckswhich are serviced according to the requirements of the car manufacturers. SJ provides the same minimum standards as SH, plus additional carbon and low temperature requirements. Engine oils meeting API SJ requirements can be used where the vehicle manufacturer recommends SH or earlier.

API SH class

Motor oils for gasoline engines since 1994.

The class was adopted in 1992 for engine oils recommended since 1993. This class is characterized by higher requirements compared to the class SG, and was developed as a replacement for the latter, to improve the anti-carbon, antioxidant, anti-wear properties of oils and increased protection against corrosion. Motor oils of this class are intended for use in gasoline engines passenger cars, minibuses and light trucks, in accordance with the recommendations of their manufacturers. Engine oils of this class have been tested in accordance with the requirements of the Chemical Manufacturers Association (CMA). Engine oils of this class can be used when the vehicle manufacturer recommends class SG or earlier.

API SG class

Motor oils for gasoline engines since 1989.

Designed for use in gasoline engines of passenger cars, minibuses and light trucks. Motor oils of this class have properties that provide improved protection against carbon deposits, engine oil oxidation and engine wear, in comparison with previous classes, and also contain additives that protect against rust and corrosion of internal engine parts. SG engine oils meet API CC diesel engine oils and can be used where SF, SE, SF / CC, or SE / CC are recommended.

API SF class

Motor oils for gasoline engines since 1980 (obsolete class).

These engine oils were used in gasoline engines from 1980-1989, subject to the recommendations and instructions of the engine manufacturer. Provide enhanced oxidation stability, improved wear protection of parts, in comparison basic characteristics motor oils SE, as well as more reliable protection against carbon deposits, rust and corrosion. Engine oils of class SF could be used as replacements for previous classes SE, SD or SC.

API SE class

Motor oils of gasoline engines produced since 1972 (obsolete class). These engine oils were used in gasoline engines produced in 1972-79, as well as some models in 1971. Additional protection in comparison with SC and SD motor oils and can be used as substitutes for these categories.

API SD class

Motor oils for use in gasoline engines since 1968 (obsolete class). Motor oils of this class were used in gasoline engines of passenger cars and some trucks produced in 1968-70, as well as some models of 1971 and later. Improved protection compared to SC engine oils, also used exclusively when recommended by the engine manufacturer.

API SC class

Motor oils for gasoline engines from 1964 (obsolete class). They were usually used in the engines of passenger cars and some trucks manufactured in 1964-1967. Reduces high and low temperature carbon deposits, wear, and also protects against corrosion.

API SB class

Motor oils for low-power gasoline engines (obsolete class). Motor oils of the 30s of the 20th century, which provided fairly light protection against wear and oxidation, as well as anti-corrosion protection for bearings in motors that are operated under light load conditions. Engine oils of this class may only be used if specifically recommended by the engine manufacturer.

API SA class

Motor oils for gasoline and diesel engines. An outdated class of oils for use in old engines operating in conditions and modes in which protection of parts with additives is not needed. Engine oils of this class can only be used if they are recommended by the engine manufacturer.

API Engine Oil Grades: Diesel Engines

API class CJ-4

Designed for heavy duty engines, licensed since October 2006.

Meets key NOx and particulate emissions regulations for 2007 engines. For CJ-4 oils, limits are introduced for some indicators: ash content less than 1.0%, sulfur 0.4%, phosphorus 0.12%.

The new classification accommodates the requirements of the earlier API CI-4 PLUS, CI-4 categories, but introduces significant changes to the requirements in response to the needs of new engines that meet the new 2007 and later emission standards.

API Class CI-4 (CI-4 PLUS)

New performance class for diesel engine oils. Compared to API CI-4, the requirements for the specific soot content as well as volatility and high-temperature oxidation are increased. When certified in this classification, the engine oil must be tested in seventeen motor tests.

API Class CI-4

The class was introduced in 2002. These engine oils are used in modern diesel engines with different kinds injection and boost.

An engine oil corresponding to this class must contain the appropriate detergent and dispersant additives and, in comparison with the CH-4 class, has increased resistance to thermal oxidation, as well as higher dispersing properties. In addition, such motor oils provide a significant reduction in engine oil waste by reducing volatility and reducing evaporation when operating temperature up to 370 ° C, under the influence of gases. The requirements for cold pumpability have also been strengthened, the resource of clearances, tolerances and engine seals has been increased by improving the fluidity of the motor oil.

API CI-4 class introduced due to the emergence of new, more stringent requirements for ecology and toxicity exhaust gases, which are presented to engines manufactured from October 1, 2002.

API class CH-4

The class was introduced on December 1, 1998. Motor oils of this class are used in four-stroke diesel engines that operate in high-speed modes and comply with the requirements of the norms and standards for exhaust gas toxicity adopted in 1998.

API CH-4 motor oils meet the stringent requirements of both American and European diesel engine manufacturers. The class requirements are specially designed for use in engines running on high quality fuels with a sulfur content of up to 0.5%. Moreover, unlike aPI class CG-4, the resource of these engine oils is less sensitive to the use of diesel fuel with a sulfur content of more than 0.5%, which is especially important for countries South America, Asia, Africa.

API CH-4 engine oils meet increased requirements and must contain additives that more effectively prevent valve wear and the formation of carbon deposits on the internal surfaces. They can be used as replacements for API CD, API CE, API CF-4 and API CG-4 engine oils in accordance with the engine manufacturer's recommendations.

API Class CG-4

The class was introduced in 1995. Motor oils of this class are recommended for four-stroke diesel engines of buses, trucks and tractors of mainline and non-mainline types, which are operated under increased loads, as well as high-speed modes. API CG-4 engine oil is suitable for engines that use high-quality fuels with a specific sulfur content of no more than 0.05%, as well as for engines for which there are no special requirements for fuel quality (specific sulfur content can reach 0.5% ).

Automotive oils certified in accordance with API CG-4 class should more effectively prevent wear of internal engine parts, formation of carbon deposits on internal surfaces and pistons, oxidation, foaming, and soot formation (these properties are especially needed for modern engines. main buses and tractors).

API CG-4 class was created in connection with the approval in the United States of new requirements and standards for the ecology and toxicity of exhaust gases (1994 revision). Motor oils of this class can be used in engines for which API CD, API CE and API CF-4 classes are recommended. The main drawback limiting the massive use of this class of motor oils, for example, in Eastern Europe and Asia, is the significant dependence of the motor oil resource on the quality of the fuel used.

API class CF-2 (CF-II)

Car oils intended for use in two-stroke diesel engines that are operated in difficult conditions.

The class was introduced in 1994. Motor oils of this class are usually used in two-stroke diesel engines that operate under high stress conditions. API CF-2 oils must contain additives that provide enhanced performance protection against wear on internal engine parts such as cylinders and rings. In addition, these car oils should prevent the accumulation of deposits on the internal surfaces of the engine (improved cleaning function).

API CF-2 engine oil has improved properties and can be used in place of older comparable oils, subject to the manufacturer's recommendation.

API class CF-4

Engine oils for use in four-stroke diesel engines since 1990.

Motor oils of this class can be used in four-stroke diesel engines, the operating conditions of which are associated with high-speed modes. For such conditions, the requirements for the quality of oils exceed the capabilities of the CE class, therefore CF-4 engine oils can be used instead of CE oils (subject to the appropriate recommendations of the engine manufacturer).

API CF-4 motor oils must contain appropriate additives that reduce the waste of the car oil, as well as protect against carbon deposits in piston group... The main purpose of motor oils of this class is the use in diesel engines of heavy-duty tractors and other vehicles that are used for long journeys on highways.

In addition, these engine oils are sometimes assigned the API CF-4 / S dual grade. In this case, subject to the availability of the appropriate recommendations of the engine manufacturer, these oils can also be used in gasoline engines.

API CF class (CF-2, CF-4)

Indirect injection diesel engine oils. Classes were introduced from 1990 to 1994. A hyphenated number means two- or four-stroke engine.

Class CF describes engine oils recommended for use in diesel engines with indirect injection, as well as other types of diesel engines that run on fuels of various qualities, including those with a high sulfur content (for example, more than 0.5% of the total mass).

CF engine oils contain additives to better prevent piston deposits, wear and corrosion of copper (copper) bearings, which are important for these types of engines, and can be pumped in the usual way as well as with a turbocharger or compressor. Engine oils of this class can be used where the CD quality class is recommended.

CE API class

Engine oils for use in diesel engines from 1983 (obsolete class).

Motor oils of this class were intended for use in some heavy-duty turbocharged engines, characterized by significantly increased working compression. The use of such oils was allowed for engines with both low and high shaft speeds.

API CE engine oils have been recommended for low and high speed diesel engines manufactured since 1983 that have been operated under high load conditions. Subject to the availability of appropriate recommendations of the engine manufacturer, these oils could also be used in engines for which CD class engine oils were recommended.

API class CD-II

Motor oils for use in heavy-duty diesel engines with two-stroke working cycle (obsolete class).

The class was introduced in 1985 for use in two-stroke diesel engines and is, in fact, an evolutionary development of the previous API CD class. The main purpose of the use of such auto oils was the use in heavy powerful diesel engines, which were installed mainly on agricultural machinery.

Motor oils of this class meet all the working standards of the previous CD class, in addition, the requirements for highly effective engine protection against carbon deposits and wear have been significantly increased.

API CD class

Motor oils for diesel engines with increased power used in agricultural machinery (obsolete class).

The class was introduced in 1955 for normal use in some diesel engines, both naturally aspirated and turbocharged, with increased cylinder compression, where effective protection against soot and wear is essential. Engine oils of this class could be used in cases where the engine manufacturer did not put forward additional requirements for the quality of the fuel (including fuels with a high sulfur content).

API CD motor oils were supposed to provide increased protection against corrosion of bearings and high-temperature carbon deposits in diesel engines, in comparison with previous classes. Engine oils in this class are often referred to as "Caterpillar Series 3" due to their compliance with the Caterpillar Tractor Company Superior Lubricants (Series 3) certification.

API CC class

Motor oils for diesel engines that operate under medium load conditions (obsolete class).

The class was introduced in 1961 for use in some engines, both naturally aspirated and turbocharged, which were characterized by increased compression. Motor oils of this class are recommended for engines that have been operated under moderate and high load.

Compared to earlier grades, API CC engine oils were required to provide a higher level of protection against high temperature carbon deposits and bearing corrosion in diesel engines, as well as rust, corrosion and low temperature carbon deposits in gasoline engines.

CB API class

Engine oils for diesel engines operating at medium load (obsolete class).

The class was approved in 1949 as an evolutionary development of the CA class when using fuels with a high sulfur content without special quality requirements. API CB motor oils were also intended for use in supercharged engines that were operated in light and moderate conditions. This class has often been referred to as "Appendix 1 Engine Oils", thereby emphasizing compliance with the military regulation MIL-L-2104A Appendix 1.

CA API class

Motor oils for lightly loaded diesel engines (obsolete class).

Motor oils of this class are intended for use in diesel engines operating in light and moderate modes on high-quality diesel fuel. In accordance with the recommendations of car manufacturers, they can also be used in some gasoline engines that are operated in moderate modes.

The class was widely used in the 40s and 50s of the last century and cannot be used in modern conditions, unless it is provided for by the requirements of the engine manufacturer.

API CA engine oils must have properties that provide protection against carbon deposits on piston rings, as well as against corrosion of bearings in supercharged engines, for which there are no special requirements for the quality of the fuel used.

It is useful for every car owner to be able to decipher the information placed on the labels of engine oils. When using a high quality product, stable long-term engine operation is possible internal combustion car.

The characteristics of the lubricants must comply with all the declared data from the manufacturers. Engine oils operate under constant high pressure over a wide temperature range. Therefore, the requirements for increased rigidity are imposed on them.

International standards

To facilitate the choice of lubricant for a car, it is recommended to use generally accepted classification principles:

1. GOST.
2. ILSAC.
3. ACEA.

The most popular systems are GOST, API, ACEA.

Depending on the type of engine, lubricants are divided into gasoline and diesel. In addition, there is a universal type of lubricant. Product packaging contains information on the purpose of the liquid. All motor substances contain a mineral base and special additives in the required amount.

By chemical composition, lubricants are classified into:

1. Mineral.
2. Synthetic.
3. Semi-synthetic.

Information about the belonging of a substance to a certain class is placed on the product label.

The packing container with engine oil also informs about:

• additives present in the solution;
• barcode;
• density classification (SAE viscosity);
• advice from car manufacturers;
• engine oil categories;
• batch number and release date.

API engine oil

The API classification of engine oils categorizes them according to the following factors:

1. Motor type.
2. The operating mode of the internal combustion engine.
3. Useful properties of oil.
4. Commissioning date.

Depending on the type of engine, engine oils are classified into categories "S" and "C". For gasoline and diesel, respectively.

API engine oil specification

API labeling begins with an "S" or "C" category. Then there is a sign that determines the class of motor fluid. This value depends on the level of useful characteristics.

Reading the API label:

1. EU - Energy Saving Oil.
2. Roman numerals - fuel economy.
3. "C" - for diesel engines.
4. "S" - for gasoline.
5. Universal brands are indicated by symbols separated by a fraction (for example, APISL / CF).
6. The letters after "S" or "C" indicate the degree of performance, they are in the range from A to N (the highest indicator of the class of the product).
7. Diesel oils are 2-stroke and 4-stroke (at the end there are 2 or 4, respectively).

After passing the API and SAE checks and fixing their compliance with quality requirements, the original round sign with the corresponding inscriptions is placed on the labels:

• at the top - APISERVISE;
• in the center - SAE with viscosity;
• below - the degree of energy saving.

An API-compliant engine fluid improves durability and reduces the risk of failure of a vehicle's internal combustion engine. At the same time, the consumption of fuel and engine oil is also reduced, extraneous sounds in the motor, driving performance is improved.

One of the main advantages is the stability of the operation of the power unit at minus temperatures and a decrease in harmful emissions.

SAE Lubricating Fluids

The SAE table categorizes engine oils by gravity based on ambient temperature. The SAE table contains three types of lubricants that differ in their structure:

1. Winter oils.
2. Summer lubricants.
3. All-season oils.

Lubricants in the first category have the most fluid consistency. This makes it easier to start the engine at low subzero temperatures outside the car. This type of lubricant is classified according to SAE letter W (5 W, 10 W, etc.).

Engine oils marked with the letter W are not recommended for use in the summer, since a too liquid consistency of this lubricant does not contribute to the formation of a lubricating film on the working surfaces of the power unit parts. The lubricating layer is not formed, and useful functions are not performed.

Summer oils are indicated for use at air temperatures above 0 ° C. Their viscosity level is quite high. At high atmospheric temperatures, the fluidity of summer grades of lubricants makes it possible to effectively lubricate the working parts and components of the internal combustion engine.

Summer lubricants are not recommended for use in winter cold, the oil with a high viscosity will not allow the engine to start in cold weather. There are no letters in the marking of summer lubricants. The designation consists of bare numbers indicating the viscosity of the substance according to SAE (10, 15, etc.).

All-seasons are the most popular. Among the analogues, they are most in demand in the automotive market. Multigrade engine oil is recommended for use in any weather at high and low ambient temperatures. They are double SAE-labeled (e.g. SAE 10W-30).

Viscosity is decisive in the marking of a lubricant. However, with the right choice engine oil for your car, you must also take into account its other characteristics:

• influence on the wear resistance of parts;
• detergent properties;
• resistance against oxidative processes;
• anti-corrosion properties, etc.

Before buying a lubricant for your car, you need to consider important factors that have a great influence on the stability of the power unit, as well as on the service life of its parts and assemblies.

IN this list factors include the following positions:

1. Which oil to choose according to its chemical composition - mineral, synthetic, semi-synthetic.
2. Study of SAE viscosity requirements (summer, winter, all-season, viscosity tolerances).
3. Availability of required additives in accordance with API and ACEA classifications.
4. Determination of the recommended brands and models of vehicles for the use of a particular lubricant (this information is contained on the product label).
5. Study additional parameters and the tolerances of lubricating fluids (for example, the Longlife mark indicates its use in vehicles with an extended period between the service periods of a complete engine oil change).
6. Some motor fluids are intended for use in power unitsequipped with intercoolers, turbocharging, adjustable valve lift, valve timing, lowering the temperature of the recirculated gases.

API is translated literally - American Fuel Institute. API employees certify and license new motor oils of all brands. They are also developing new state-of-the-art specifications and quality standards for oil fluids used in diesel and gasoline engines.

Base lubricants are also subject to rigorous analysis and testing.

Additional classifications to the API system

Separating modern lubricants into diesel and gasoline alone is not enough. The technologies for the production of internal combustion engines are growing, in accordance with this, the requirements for oils are also increasing. API staff are working to create new standards and specifications.

Organizations for licensing and certification of lubricant products are being created on their basis: ILSACGF, Energy Conserving (EC).

APISM requirements

The new specifications require APISM engine oils to meet the following additional requirements:

• ensuring resistance against wear of parts and components of the power unit;
• increased time interval between full replacements oils;
• preservation of the declared useful properties and characteristics during the entire period of operation;
• resistance to oxidative processes;
• frost resistance of the lubricant.

APISN classification requirements

In connection with the emergence of motors with various "bells and whistles", there are additional requirements for lubricants. APISN-certified engine oils meet the following requirements:

1. Energy saving, these lubricants are suitable for use in biofuel vehicles.
2. Providing a higher wear resistance of the power unit.
3. Exhaust gas cleanliness.
4. Safety of the engine sealing elements.

The last point testifies to the concern of manufacturers of lubricant products about gaskets and oil seals of internal combustion engines. APISN requires manufacturers to monitor the engine, its components and parts, as well as the condition of rubber products installed in the engines.

The very essence of engine oil in the engine is to prevent overheating of moving parts and, as a result, premature wear. If the engine oil is selected correctly, the functions are fulfilled and its stable oil film does not allow excessive friction - the power unit will last a long time and without breakdowns.

It is accepted to consider operating temperature of the engine t ° about 90 degrees... But if you look at it, then this is the temperature of the antifreeze, and in the engine it can reach 150 degrees. It all depends on the type of engine and the driver's driving style.

One of the main conditions for stable operation of the power unit is the correct viscosity.

If the selection was correct, the engine oil is guaranteed to remain on the surface of the rubbing elements, regardless of its temperature.

The viscosity value is indicated most often in two numbers through W(eg 10 W 40 )

API classification for engine oils on the S scale

To indicate that the oil belongs to gasoline, it was customary to put the letter at the beginning of the class S (i.e Service). It is followed by letters in alphabetical order, which characterizes the relevance of the engine oil class .

the category was introduced in 2010. Motor oils have the lowest possible phosphorus content, which makes it possible to use the current emission filtration systems, as well as a high level of energy saving. Regardless of its high temperature fluidity, API SN can be classified as C2, C3 and C4 according to CEA guidelines.

API SM

oils in this category are distinguished by increased, compared to the previous classes, resistance to corrosion and oxidation. The API SM category is often found accompanied by ILSAC with energy saving properties. Oil may be used if one of the previous categories is recommended.

API SL

the category is valid to this day. Note that in the sequence of letters after the S in the categories, the letter K (i.e. SK) is missing. This was done deliberately due to the fact that one of the Korean oil trading organizations uses this combination of letters in their corporate name. API SL is superior in properties to the previous categories.

SJ API

this category is valid to this day. Agreed in 1996 Exceeds all previously accepted tolerances. Apply for passenger cars, jeeps, minibuses and light trucks. There is a possibility of certification according to the class of oils with energy saving properties EC.

API SH

oils of this class are oriented to gasoline engines produced after 1996. Today, the possibility of using this licensed category is possible, but subject to the addition of another API category (for example SH / EC). If the oil was classified as fuel saving, it was assigned an EC II approval.

API SG

focused on vehicles manufactured after 1989 Can be used in all vehicles except for highly loaded. Has higher performance properties compared to the previous tolerance. Excellent protection against deposits in high temperature environments. This category is considered obsolete today. Leaded gasoline is allowed.

API SF

an outdated class, which means car models created after 1988, more or less viable antioxidant, anticorrosive and extreme pressure additives have already been used. Added detergent properties. Fuel is leaded gasoline.

API SE

obsolete class, created for high-powered engines developed (from 1972 - 80)

API SD

obsolete class, designed for loaded forced vehicles (from 1968 - 71)

API SC

obsolete class, developed (from 1964 - 67) for loaded vehicles of that time.

API SB

the use of such oil can only be found subject to the requirements of the automaker. It is used in light-duty vehicles.

API SA

tolerance implies the ability to use fuel with a low sulfur content also in unloaded engines of light vehicles

The American Petroleum Institute's engine oil classification system was established in 1969. Usually, aPI classification associated with the quality of engine oil.

The API classification divides engine oils into two types - oil for gasoline engines and oil for diesel engines. For each of these types there are quality classes that describe a set of properties and characteristics of the oil. The lack of information on the engine oil label of compliance with any of the API classes means that this oil either does not have an API certificate at all, or the quality class assigned to it is very outdated.

The first letter of the coding indicates the type of oil:

S - oil for gasoline engines
C - oil for diesel engines.

There are oils that can be used in both types of engines. This oil is assigned two classes - for diesel and for gasoline engines. On the oil label, these classes are separated by a forward slash (slash) - for example, API SL / CF approval. In this case, the first is the class of oil that corresponds to the more preferable (according to the manufacturer of the car oil) application. That is, in the above case, the main purpose of the car oil is for gasoline engines, but at the same time the manufacturer allows its use in diesel engines.

API Classes for Gasoline Engines

API SM -class approved on November 30, 2004. Engine oils for modern gasoline (multivalve, turbocharged) engines. Compared to the SL class, engine oils that meet API SM requirements must have better protection against oxidation and premature wear of engine parts. In addition, standards have been raised regarding oil properties at low temperatures. Engine oils of this class can be certified according to the ILSAC energy efficiency class. Engine oils meeting the requirements of API SL, SM can be used in cases where the car manufacturer recommends class SJ or earlier.

API SL - motor oils for engines of cars manufactured after 2000. In accordance with the requirements of car manufacturers, motor oils of this class are used in multivalve, turbocharged engines operating on lean fuel mixtures that meet modern increased environmental requirements, as well as energy saving. Automotive oils that meet API SL requirements can be used in cases where the car manufacturer recommends the SJ class or earlier.

SJ API - engine oils for use in gasoline engines since 1996. API SJ class describes motor oils that are used in gasoline engines since 1996. Motor oils of this class are intended for use in gasoline engines of cars and sports cars, vans and light trucks, which are serviced in accordance with the requirements of car manufacturers. SJ provides the same minimum standards as SH, plus additional carbon and low temperature requirements. Engine oils meeting API SJ requirements can be used when the vehicle manufacturer recommends SH class or earlier.

API SH- motor oils for gasoline engines since 1994. The class was adopted in 1992 for engine oils recommended since 1993. This class is characterized by higher requirements compared to the class SG, and was developed as a substitute for the latter, to improve the anti-carbon, antioxidant, anti-wear properties of oils and increased protection against corrosion. Motor oils of this class are intended for use in gasoline engines of passenger cars, vans and light trucks, in accordance with the recommendations of their manufacturers. Engine oils of this class have been tested in accordance with the requirements of the Chemical Manufacturers Association (CMA). Engine oils of this class can be used when the vehicle manufacturer recommends class SG or earlier.

API SG- motor oils for gasoline engines since 1989. Designed for use in gasoline engines of passenger cars, minibuses and light trucks. Motor oils of this class have properties that provide improved protection against carbon deposits, engine oil oxidation and engine wear, in comparison with previous classes, and also contain additives that protect against rust and corrosion of internal engine parts. SG engine oils meet API CC diesel engine oils and can be used where SF, SE, SF / CC, or SE / CC are recommended.

API SF- motor oils for gasoline engines since 1980 (obsolete class). These engine oils were used in gasoline engines from 1980-1989, subject to the recommendations and instructions of the engine manufacturer. Provides enhanced oxidation stability, improved wear protection compared to baseline SE lubricants, as well as better protection against carbon deposits, rust and corrosion. Engine oils of class SF could be used as replacements for previous classes SE, SD or SC.

API SE - motor oils of gasoline engines produced since 1972 (obsolete class). These engine oils were used in gasoline engines produced in 1972-79, as well as some models in 1971. Additional protection in comparison with SC and SD motor oils and can be used as substitutes for these categories.

API SD - motor oils for use in gasoline engines since 1968 (obsolete class). Motor oils of this class were used in gasoline engines of passenger cars and some trucks produced in 1968-70, as well as some models of 1971 and later. The improved protection compared to SC engine oils was also used only when recommended by the engine manufacturer.

API SC - motor oils for gasoline engines, since 1964 (obsolete class). They were usually used in the engines of passenger cars and some trucks produced in 1964-1967. Reduces high and low temperature carbon deposits, wear, and also protects against corrosion.

API SB - motor oils for low-power gasoline engines (obsolete class). Motor oils of the 30s of the 20th century, which provided fairly light protection against wear and oxidation, as well as anti-corrosion protection for bearings in motors that are operated under light load conditions. Engine oils of this class may only be used if specifically recommended by the engine manufacturer.

API SA - motor oils for gasoline and diesel engines. An obsolete class of oils for use in old engines operating in conditions and modes in which protection of parts with additives is not needed. Engine oils of this class can only be used if they are recommended by the engine manufacturer.

API classes for diesel engines

API CI-4 (CI-4 PLUS) - a new performance class of engine oils for diesel engines. Compared to API CI-4, the requirements for the specific soot content as well as volatility and high-temperature oxidation are increased. When certified in this classification, the engine oil must be tested in seventeen motor tests.

API CI-4 - the class was introduced in 2002. These engine oils are used in modern diesel engines with various types of injection and pressurization. An engine oil corresponding to this class must contain the appropriate detergent and dispersant additives and, in comparison with the CH-4 class, has increased resistance to thermal oxidation, as well as higher dispersing properties. In addition, such motor oils provide a significant reduction in engine oil waste by reducing volatility and reducing evaporation at operating temperatures up to 370 ° C, under the influence of gases. The requirements for cold pumpability have also been strengthened, the resource of clearances, tolerances and engine seals has been increased by improving the fluidity of the motor oil. API CI-4 class was introduced in connection with the emergence of new, more stringent requirements for the ecology and toxicity of exhaust gases, which are imposed on engines manufactured from October 1, 2002.

API CH-4 - the class was introduced on December 1, 1998. Motor oils of this class are used in four-stroke diesel engines that operate in high-speed modes and meet the requirements of the norms and standards for exhaust gas toxicity adopted in 1998. API CH-4 motor oils meet the stringent requirements of both American and European diesel engine manufacturers. The class requirements are specially designed for use in motors running on high quality fuels with a sulfur content of up to 0.5%. At the same time, unlike API CG-4 class, the resource of these motor oils is less sensitive to the use of diesel fuel with a sulfur content of more than 0.5%, which is especially important for the countries of South America, Asia, and Africa. API CH-4 engine oils meet increased requirements and must contain additives that more effectively prevent valve wear and the formation of carbon deposits on the internal surfaces. They can be used as replacements for API CD, API CE, API CF-4 and API CG-4 engine oils in accordance with the engine manufacturer's recommendations.

API CG-4 - class presented in 1995. Motor oils of this class are recommended for four-stroke diesel engines of buses, trucks and tractors of mainline and non-mainline types, which are operated under increased loads, as well as high-speed modes. API CG-4 engine oil is suitable for engines that use high-quality fuels with a specific sulfur content of not more than 0.05%, as well as for engines that do not have special requirements for fuel quality (specific sulfur content can reach 0.5% ). Automotive oils certified according to the API CG-4 class should more effectively prevent wear of internal engine parts, the formation of carbon deposits on internal surfaces and pistons, oxidation, foaming, and soot formation (these properties are especially needed for engines of modern main-line buses and tractors). API CG-4 class was created in connection with the approval in the United States of new requirements and standards for the ecology and toxicity of exhaust gases (1994 revision). Motor oils of this class can be used in engines for which API CD, API CE and API CF-4 classes are recommended. The main drawback limiting the massive use of this class of motor oils, for example, in Eastern Europe and Asia, is the significant dependence of the motor oil resource on the quality of the fuel used.

API CF-2 (CF-II) - motor oils designed for use in two-stroke diesel engines that are operated in difficult conditions. The class was introduced in 1994. Motor oils of this class are usually used in two-stroke diesel engines that operate under high stress conditions. API CF-2 oils must contain additives that provide enhanced performance protection against wear on internal engine parts such as cylinders and rings. In addition, these motor oils should prevent the accumulation of deposits on the internal surfaces of the engine (improved cleaning function). An API CF-2 certified engine oil has improved properties and can be used in place of earlier comparable oils, subject to the manufacturer's recommendation.

API CF-4 - engine oils for use in four-stroke diesel engines since 1990. Motor oils of this class can be used in four-stroke diesel engines, the operating conditions of which are associated with high-speed modes. For such conditions, the requirements for the quality of oils exceed the capabilities of the CE class, therefore CF-4 engine oils can be used instead of CE oils (subject to the appropriate recommendations of the engine manufacturer). API CF-4 motor oils must contain appropriate additives that reduce the waste of the car oil, as well as protect against carbon deposits in the piston group. The main purpose of motor oils of this class is the use in diesel engines of heavy-duty tractors and other vehicles that are used for long-distance trips on highways. In addition, these engine oils are sometimes assigned the API CF-4 / S dual grade. In this case, subject to the availability of appropriate recommendations from the engine manufacturer, these oils can also be used in gasoline engines.

API CF (CF-2, CF-4) are engine oils for diesel engines with indirect injection. Classes were introduced from 1990 to 1994. A hyphenated number indicates a two- or four-stroke engine. Class CF describes engine oils recommended for use in diesel engines with indirect injection, as well as other types of diesel engines that run on fuels of various qualities, including those with a high sulfur content (for example, more than 0.5% of the total mass). CF engine oils contain additives to better prevent piston deposits, wear and corrosion of copper (copper) bearings, which are important for these types of engines, and can be pumped in the usual way as well as with a turbocharger or compressor. Engine oils of this class can be used where the CD quality class is recommended.

API CE - engine oils for use in diesel engines from 1983 (obsolete class). Motor oils of this class were intended for use in some super-powerful turbocharged engines, characterized by a significantly increased working compression. The use of such oils was allowed for engines with both low and high shaft speeds. API CE engine oils have been recommended for low and high speed diesel engines manufactured since 1983 that have been operated under high load conditions. Subject to the availability of appropriate recommendations from the engine manufacturer, these oils could also be used in engines for which CD class engine oils were recommended.

API CD-II - engine oils for use in heavy-duty diesel engines with a two-stroke working cycle (obsolete class). The class was introduced in 1985 for use in two-stroke diesel engines and is, in fact, an evolutionary development of the previous API CD class. The main purpose of the use of such motor oils was the use in heavy powerful diesel engines, which were installed mainly on agricultural machinery. Motor oils of this class meet all working standards of the previous CD class, in addition, the requirements for highly effective engine protection against carbon deposits and wear are significantly increased.

API CD - motor oils for diesel engines of increased power, which were used in agricultural machinery (obsolete class). The class was introduced in 1955 for normal use in some diesel engines, both naturally aspirated and turbocharged, with increased cylinder compression, where effective protection against soot and wear is essential. Motor oils of this class could be used in cases where the engine manufacturer did not put forward additional requirements for the quality of the fuel (including fuels with a high sulfur content). API CD auto oils were supposed to provide increased protection against corrosion of bearings and high-temperature carbon deposits in diesel engines, in comparison with previous classes. Engine oils in this class are often referred to as "Caterpillar Series 3" due to their compliance with the Caterpillar Tractor Company Superior Lubricants (Series 3) certification.

API CC - motor oils for diesel engines that are operated at medium load conditions (obsolete class). The class was introduced in 1961 for use in some engines, both naturally aspirated and turbocharged, which were characterized by increased compression. Motor oils of this class are recommended for engines that have been operated under moderate and high load. In addition, subject to the availability of the engine manufacturer's recommendations, such oils could be used in some powerful gasoline engines. Compared to earlier grades, API CC engine oils were required to provide better protection against high temperature carbon deposits and bearing corrosion in diesel engines, as well as rust, corrosion and low temperature carbon deposits in gasoline engines.

API CB - motor oils for diesel engines operating with medium load (obsolete class). The class was approved in 1949 as an evolutionary development of the CA class when using fuels with a high sulfur content without special quality requirements. API CB motor oils were also intended for use in supercharged engines that were operated in light and moderate conditions. This class was often referred to as "Appendix 1 Engine Oils", thereby emphasizing compliance with the military regulation MIL-L-2104A Appendix 1.

CA API - motor oils for lightly loaded diesel engines (obsolete class). Motor oils of this class are intended for use in diesel engines operating in light and moderate modes on high-quality diesel fuel. In accordance with the recommendations of car manufacturers, they can also be used in some gasoline engines that are operated in moderate modes. The class was widely used in the 40s and 50s of the last century and cannot be used in modern conditions, unless it is provided for by the requirements of the engine manufacturer. API CA engine oils must have properties that provide protection against carbon deposits on piston rings, as well as against corrosion of bearings in supercharged engines, for which there are no special requirements for the quality of the fuel used.

The fuels and lubricants produced on the global automotive market and the market have standards and regulations. One of the most important standards is the API specification system. This classification of automotive oils used to protect internal combustion engines was developed by the American Petroleum Institute (API), from which the world famous abbreviation is derived. The main parameters for the standardization and classification of engine oil into categories are the scope of the lubricant, as well as the performance of the product.

This association is the only one in the United States that has the status of a national non-governmental organization. The Institute's field of activity includes research on all processes that regulate functional operational aspects in the oil and gas industry.

The American Petroleum Institute, which develops API oil specifications, was formed in 1919. Its initial tasks were interaction with government agencies in solving problems at the national level, assistance in promoting the sale of the country's own oil products in domestic and foreign trade, increasing interest and demand for the national oil industry in all sales categories.

Also, one of the directions of development of the Institute of Oil was determined by the development of standards and norms. The first API standards and specifications were shown to a wide audience in 1924. Today in modern production facilities the organization maintains over 500 regulations and standards that operate in all areas of the oil and gas industry. The purpose of the specifications is to promote the safe use of equipment, materials, and proven engineering practices.

Lubricating fluids were used long before the emergence and development of modern scientific and technical base. Previously, vegetable or animal fats were used as lubricants. In the middle of the last century, natural oils replaced petroleum products. From that moment on, the progress in the development of engine oils increased dramatically. IN molecular structure lubricants, viscosity modifiers appeared. Thanks to them, engine oils began to be divided into classes and types that function under certain temperature conditions, universal types of oils appeared, which subsequently received API approvals and specifications.

Over time, the structural composition and technical specifications have undergone many changes, but the main task of motor lubricating fluids has remained unchanged. Engine oil should protect parts and assemblies from friction and premature wear by enveloping the latter with an oil film, penetrating into all gaps and technical gaps.

API oil was developed by the American Petroleum Institute in 1969. This classification divided lubricants into the following groups:

• lubricants used in engines with gasoline fuel, are marked with the letter "S" (Service);
• lubricants used in engines with diesel fuel, are marked with the letter "C" (Commercial);
• transmission greases are marked "GL";
• oils used in two-stroke engines, marking "T".

There is also a category of lubricating fluids labeled "EC" (Energy Conserving). This group is characterized as an energy-saving category of oils. Numerous tests and studies have provided guaranteed confirmation of this category.

Engine oils differ in terms of service and workmanship. This was taken into account in the API specifications. Based on this, in different groups there are lubricants that have been distributed according to quality parameters and performance properties. On the packaging, the marking of such products is as follows: API SM, API CF, etc.

The first letter in the marking accordingly indicates the type of engine, the second one determines the level indicator performance characteristics... It should be noted the regular ratio of the second letter in the marking: the further from the beginning of the Latin alphabet is the letter, the higher the oil level according to the API specification.

There is also a category of oils with approvals for use in both gasoline engines and diesel units. Such a product is appropriately labeled, for example, API SN / CH. This example indicates that the grease is also suitable for gasoline engine, and for diesel, but the manufacturer prefers power units with gasoline fuel.

Category S Initial Specifications

SA. The very first type of oil fluid standard that was used in engines up to the 30s of the last century. Does not contain additives. Application in more modern engines can only be justified as recommended by the powertrain manufacturer. Otherwise, oil with this specification may damage the device.

SB. Marked oil after the 30s for engines with low load. Not recommended for modern units.

SC. Lubricant for engines manufactured between 1964 and 1967 It was characterized by weak anti-corrosion properties.

SD. This specification by Engine API oils were produced until 1971 and differed from the previous one in improved parameters.

SF. Operation period 1981-1989 It has improved wear, sludge and acid resistance properties.

SG. The specification was applied from 1989 to 1995. Additives appeared in the oil.

SH. May supersede previous specifications. It has a set of additives in its composition, well prevents soot, high anti-corrosion properties.

Modern specifications

SJ. It is still in operation today. Standardization was carried out in 1995. Possesses good lubricating and protective properties.

SL. Designed for use in powertrains that were manufactured in compliance with 2000 environmental standards. Helps to reduce fuel consumption.

SM. The API SM specification was oriented during development to maximize energy efficiency and sustainability. The oil has high protective properties. Resists oxidative processes as much as possible, prevents the formation of slags and carbon deposits on the engine walls. Suitable for motors with a turbine.

SN. API SN specification - the most modern classification oils, which meets all the latest requirements for environmental friendliness, safety and reliability of the internal combustion engine. The percentage of phosphorus has been reduced. Affects fuel consumption in favor of economy.

Category C specification

Specifications CA, SV, CC, CD, CE are technically outdated and are not recommended for use in modern engines.

The most popular API CF specifications are:

• API CF 4 - for four-stroke diesel engines with high loads;
• API CF 2 - for two-stroke engines.

The most recent specification in the diesel category is CJ 4. Conforms to all global standards and requirements.