Oils complying with the requirements of class CI-4 are designed for operation under severe conditions of 4-stroke diesel engines of trucks equipped with an exhaust gas recirculation system. Such systems are installed on new models of automotive diesel engines in order to reduce the toxicity of exhaust gases.
Returning part of the exhaust gases to the exhaust effectively suppresses the formation of nitrogen oxides during the combustion process, but sharply increases the requirements for the neutralizing, anti-wear and anti-corrosion properties of the oil used. Previously, an oil film on the cylinder wall interacted with combustion products only in expansion and exhaust strokes when the temperature of the gases was high. Now, during exhaust gas recirculation, the combustion products come into contact with the oil film in the intake and compression strokes when the temperature of the gases is much lower and conditions arise for the formation of acids.
Class CI-4 oils should be used in combination with fuels containing not more than 0.05% sulfur. But even under such conditions, exhaust gas recirculation is a factor in seriously tightening the requirements for the neutralizing ability of the oil. Studies have shown that it becomes important not only its high alkaline number, but also the rate of neutralization of acids with oil additives.
At the optimum temperature of the coolant and oil in the crankcase, the inclusion of exhaust gas recirculation accelerates the decrease in alkalinity by 1.5 times.
If the motor is not warmed up enough, the decrease in alkalinity increases dramatically. Rapid warming up of the engine and maintaining optimal thermal conditions are extremely important for maintaining the oil’s working capacity.
In terms of operational properties, oils of class CI-4 significantly surpass their old predecessors (CH-4, CG-4 and CF-4) and can replace them in engines of models of the late 90s. With such a change, the mileage before changing the oil can be significantly increased.
A wide range of laboratory and motor tests is used to certify oils for compliance with class CI-4, in which there are several new methods, including long-term motor tests in engines with exhaust gas recirculation.
Of particular note is the first introduced pumpability control at -20 ° C of oil that worked in the engine during bench tests for 75 hours, as well as a strict assessment of the anticorrosion properties of the oil with respect to lead, copper and tin.
The only indicator by which new American diesel oils are inferior to European is evaporation. The norm for class CI-4 SAEW-40 is no more than 18%, and according to the European classification ACEA, oils for diesel engines of trucks (class E) are no more than 13% for 1 hour at a temperature of 250 ° C. These differences, however, are not accompanied by reduced requirements for oil consumption during motor tests.
The API engine oil classification system () was created in 1969. Three operational categories (three rows) of purpose and quality of engine oils are established by the API system:
S (Service) - consists of quality categories of motor oils for gasoline engines running in chronological order.
C (Commercial) - consists of the categories of quality and purpose of oils for diesel engines going in chronological order.
EC (Energy Conserving) - energy-saving oils. A new range of high-quality oils, consisting of low-viscosity, light-flowing oils that reduce fuel consumption according to the results of tests on gasoline engines.
For each new class an additional letter is assigned alphabetically. Universal oils for gasoline and diesel engines are indicated by two symbols of the corresponding categories: the first symbol is the main one, and the second indicates the possibility of using this oil for a different type of engine. Example: API SM / CF.
API SN Class - approved on October 1, 2010.
The main difference between API SN and previous API classifications is the limitation of phosphorus content for compatibility with modern exhaust gas aftertreatment systems, as well as integrated energy saving. That is, oils classified according to API SN will approximately correspond to ACEA C2, C3, C4, without correction for high temperature viscosity.
SM API Class - approved on November 30, 2004.
Motor oils for modern gasoline (multi-valve, turbocharged) engines. Compared with the SL class, motor oils that comply with API SM requirements must have better protection against oxidation and premature wear of engine parts. In addition, increased standards regarding the properties of oil at low temperatures. Motor oils of this class can be certified in the energy efficiency class ILSAC
API SL, SM engine oils can be used when the vehicle manufacturer recommends SJ or earlier.
API Class SL - engine oils for engine engines manufactured after 2000.
In accordance with the requirements of automobile manufacturers, motor oils of this class are used in multi-valve, turbocharged engines operating on lean fuel mixtures that meet modern high environmental requirements as well as energy conservation. API SL compliant oils can be used when the SJ or earlier is recommended by the automaker.
SJ API Class - engine oils for use in gasoline engines since 1996 of release.
This class describes motor oils that are used in gasoline engines since 1996 of release. 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 automobile manufacturers. SJ provides the same minimum standards as SH, as well as additional requirements for carbonization and low temperature operation. API SJ compliant engine oils can be used when the vehicle manufacturer recommends SH or earlier.
API SH Class- engine oils for gasoline engines since 1994 of release.
The class was adopted in 1992 for engine oils recommended since 1993. This class is characterized by higher requirements than the SG class, and was developed as a substitute for the latter to improve the anti-stick, antioxidant, anti-wear properties of oils and increased corrosion protection. Motor oils of this class are intended for use in gasoline engines of cars, vans and light trucks, in accordance with the recommendations of their manufacturers. Motor oils of this class were tested in accordance with the requirements of the Association of Chemical Manufacturers (CMA). Motor oils of this class can be used in cases where the car manufacturer recommends a grade of SG or earlier.
SG API Class- engine oils for gasoline engines since 1989 of release.
Designed for use in gasoline engines of cars, vans and light trucks. Motor oils of this class have properties that provide improved protection against soot, 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 class engine oils meet API CC diesel engine oil requirements and can be used where SF, SE, SF / CC or SE / CC classes are recommended.
API Class SF- engine oils for gasoline engines starting in 1980 (obsolete class).
These engine oils were used in gasoline engines from 1980-1989, subject to the recommendations and instructions of the engine manufacturer. They provide enhanced resistance to oxidation, improved protection against wear of parts, in comparison with the basic characteristics of SE motor oils, as well as more reliable protection against soot, rust and corrosion. Class SF motor oils could be used as substitutes for previous classes of SE, SD or SC.
API Class SE - motor oils of gasoline engines produced since 1972 (obsolete class). These motor oils were used in gasoline engines produced in 1972-79, as well as in some 1971 models. Additional protection in comparison with SC and SD motor oils can be used as substitutes for these categories.
SD API Class - motor oils for use in gasoline engines since 1968 (obsolete class). Automobile oils of this class were used in gasoline engines of cars and some freight cars manufactured in 1968-70, as well as some models of 1971 and later. Improved protection compared to SC engine oils, were also used exclusively with the recommendation of the engine manufacturer.
SC API Class - motor oils for gasoline engines starting in 1964 (outdated class). Usually used in engines of cars and some trucks produced in 1964-1967. Reduce high and low temperature deposits, wear, and also protect against corrosion.
API SB Class - motor oils for low-power gasoline engines (obsolete class). Motor oils of the 30s of the 20th century, providing fairly easy protection against wear and oxidation, as well as anti-corrosion protection of bearings in motors that are operated in light duty conditions. Motor oils of this class may only be used if they are specifically recommended by the engine manufacturer.
API Class SA - motor oils for gasoline and diesel engines. An outdated class of oils for use in older engines operating under conditions and conditions in which the protection of parts with additives is not necessary. Motor oils of this class may only be used if they are recommended by the engine manufacturer.
CJ-4 API Class- effective from October 1, 2006.
This class is designed specifically for heavy duty engines. Meets key NOx and particulate emission standards for 2007 engines. CJ-4 oils are subject to limits on some indicators: ash content less than 1.0%, sulfur 0.4%, phosphorus 0.12%.
The new classification accommodates the requirements of earlier categories API CI-4 PLUS, CI-4, but carries significant changes in the requirements in response to the needs of new engines that meet the new environmental standards of 2007 and later models.
API Class CI-4 (CI-4 PLUS) - A new operational class of diesel engine oils. Compared to API CI-4, the requirements for the specific content of soot, as well as volatility and high-temperature oxidation, are increased. When certified in this classification, motor 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 various types of injection and boost. An engine oil corresponding to this class must contain appropriate detergent-dispersant additives and, in comparison with class CH-4, have increased resistance to thermal oxidation, as well as higher dispersing properties. In addition, such motor oils provide a significant reduction in the loss of engine oil by reducing volatility and reducing evaporation at an operating temperature of up to 370 ° C, under the influence of gases. The requirements for cold pumpability have also been strengthened, the resource of clearances, tolerances and motor seals has been increased due to improved fluidity of the oil.
The 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 since October 1, 2002.
API Class CH-4 - effective from December 1, 1998.
Motor oils of this class are used in four-stroke diesel engines, which are operated in high-speed modes and meet the requirements of norms and standards for exhaust gas toxicity adopted in 1998.
API CH-4 auto oils comply with rather stringent requirements of both American and European diesel engine manufacturers. Class requirements are specifically designed for use in engines running on high-quality fuel with a specific sulfur content of up to 0.5%. At the same time, unlike the 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 advanced requirements and must contain additives that more effectively prevent valve wear and deposit formation on internal surfaces. They can be used as API CD, API CE, API CF-4 and API CG-4 engine oil substitutes in accordance with the recommendations of the engine manufacturer.
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 the main and non-main type, which are operated in high-load conditions, as well as high-speed modes. API CG-4 engine oil is suitable for engines that use high-quality fuel with a specific sulfur content of not more than 0.05%, as well as engines for which there are no special requirements for fuel quality (specific sulfur content can reach 0.5% )
API CG-4 certified motor oils should more effectively prevent wear of internal engine parts, carbon deposits on internal surfaces and pistons, oxidation, foaming, and soot formation (these properties are especially needed for engines of modern main buses and tractors).
API class CG-4 was created in connection with the approval in the USA of new requirements and standards for the ecology and toxicity of exhaust gases (1994 edition). 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 disadvantage limiting the mass use of motor vehicles of this class, for example in eastern Europe and Asia, is the significant dependence of the life of the oil on the quality of the fuel used.
API Class CF-2 (CF-II) - oils designed for use in two-stroke diesel engines that are operated in harsh conditions.
The class was introduced in 1994. Motor oils of this class are commonly used in two-stroke diesel engines that operate under high load 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 must prevent the accumulation of deposits on the internal surfaces of the motor (improved cleaning function).
API CF-2 certified motor oil has improved properties and can be used in place of earlier similar oils, subject to manufacturer's recommendation.
API Class CF-4 - engine oils for use in four-stroke diesel engines, since 1990 of release.
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 quality requirements of the oils exceed the capabilities of the CE class, therefore CF-4 engine oils can be used instead of the CE class oils (subject to the relevant recommendations of the engine manufacturer).
API CF-4 auto oils should contain appropriate additives that reduce the loss of oil, as well as protection against soot in the piston group. The main purpose of this class of motor oils is to use heavy-duty tractors and other cars in diesel engines that are used for long journeys on highways.
In addition, these API motor oils are sometimes assigned a dual API CF-4 / S grade. In this case, subject to the relevant recommendations of the engine manufacturer, these oils can also be used in gasoline engines.
API CF Class (CF-2, CF-4) - engine oils for diesel engines with indirect injection. Classes were introduced from 1990 to 1994. A hyphen indicates a two- or four-stroke engine.
Class CF describes motor 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 high sulfur content (for example, more than 0.5% of the total mass).
CF-certified motor oils contain additives that help more effectively prevent piston deposits, wear and corrosion of copper (copper-containing) bearings, which is of great importance for these types of engines and can be pumped in the usual way, as well as using a turbocharger or compressor. Motor oils of this class can be used where CD quality grade is recommended.
API CE Class - motor oils for use in diesel engines, since 1983 of release (obsolete class).
Automobiles 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 were recommended for low- and high-speed diesel engines manufactured since 1983, which were operated under high load conditions. Subject to the relevant recommendations of the engine manufacturer, these oils could also be used in motors for which CD class engine oils were recommended.
API Class CD-II - motor 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 the working standards of the previous CD class, in addition, the requirements for highly efficient engine protection against soot and wear are significantly increased.
CD API Class - motor oils for diesel engines of increased power, which were used in agricultural machinery (obsolete class). The class was introduced in 1955 for ordinary use in some diesel engines, both atmospheric and turbocharged, with increased compression in the cylinders, where effective protection against soot and wear is extremely important. Motor oils of this class could be used in cases where the engine manufacturer did not put forward additional requirements for fuel quality (including fuel with a high sulfur content).
Compared to previous classes, API CD auto oils had to provide increased protection against corrosion of bearings and high-temperature soot in diesel engines. Often, motor oils of this class were called “Caterpillar Series 3” because they met the requirements of the Superior Lubricants (Series 3) certification developed by the Caterpillar tractor company.
SS API Class - motor oils for diesel engines that are operated under medium load conditions (obsolete class).
The class was introduced in 1961 for use in some engines, both atmospheric and turbocharged, which were characterized by increased compression. Motor oils of this class were recommended for engines that were operated under moderate to high load conditions.
In addition, subject to the recommendations of the engine manufacturer, such motor oils could be used in some powerful gasoline engines.
Compared to earlier classes, API CC engine oils were supposed to provide a higher level of protection against high temperature deposits and bearing corrosion in diesel engines, as well as against rust, corrosion and low temperature deposits in gasoline engines.
CB API Class - engine oils for diesel engines operating with medium load (obsolete class).
The class was approved in 1949 as the evolutionary development of the SA class when using fuel with a high sulfur content without special quality requirements. API CB motor oils were also intended for use in supercharged engines, which were operated in light and moderate modes. Often this class was called "Motor Oils" Appendix 1 ", thereby emphasizing compliance with the military regulation MIL-L-2104A Appendix 1.
CA API Class - motor oils for lightly loaded diesel engines (obsolete class).
Automobile oils of this class are intended for use in diesel engines operating in light and moderate modes using high-quality diesel fuel. In accordance with the recommendations of car manufacturers, they can be used in some gasoline engines, which are operated in moderate conditions.
The class was widely used in the 40s and 50s of the last century and cannot be used in modern conditions, if it is not 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.
Motor Oil Classification according to the conditions of use and levels of performance of the American Petroleum Institute (API).
According to the classification API motor oils are divided into two categories: "S" (Service) and "C" (Commercial).
S (Service) - consists of quality categories of motor oils for gasoline engines running in chronological order. For each new generation an additional letter is assigned alphabetically: API SA, API SB, API SC, API SD, API SE, API SF, API SG, API SH and API SJ (category SI - API is intentionally omitted, to avoid confusion with the International system measures).
The categories API SA, API SB, API SC, API SD, API SE, API SF, API SG are now declared invalid as outdated, however, in some countries the oils of these categories are still available, the API SH category is “conditional” and may Only be used as an option, e.g. API CG-4 / SH.
The SL class was introduced in 2001 and differs from SJ in significantly better antioxidant, anti-wear, anti-foam properties, as well as less volatility.
C (Commercial) - consists of the categories of quality and purpose of oils for diesel engines going in chronological order. For each new generation an additional letter is assigned alphabetically: API CA, API CB, API CC, API CD, API CD-II, API CE, API CF, API CF-2, API CF-4, API CG-4 and API CH -4.
The categories API CA, API CB, API CC, API CD, API CD-II are now declared invalid as outdated, however, in some countries, oils of these categories are still available.
Classes of oils indicating the area of \u200b\u200bapplication are indicated by the letters of the Latin alphabet in ascending order behind the category designation: "Service" (SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM, SN), "Commercial" (CA, CB, CC, CD, CD +, CD-II, CE, CF-4, CF-2, CG-4, CH-4, SI-4). The numbers in the designations of the classes CDII, CF-4, CF-2, CG-4 provide additional information on the applicability of oils of this class in 2-stroke or 4-stroke engines. The introduction of each new class was due to the tightening of requirements for oils, in particular, caused by environmental laws, the expansion of the use of turbocharged engines, exhaust gas recirculation.
For the designation of universal oils, i.e. those that can be used to lubricate gasoline and diesel engines, double marking is adopted, for example SF / CC, CF-4 / SH, etc.
For gasoline engines - oil classes on the S scale |
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| Oil group | Years of car production | Qualitative indicators | |
| Sm |
Introduced in November 2004. Technological development trends are aimed at increasing their environmental safety, increasing maintenance intervals while maintaining reliability. Naturally, this makes its own adjustments to the process of improving engines, being reflected on the qualities of lubricants. Following these trends, in November 2004, the API classification introduced a class for motor oils for gasoline engines - SM, which implies, in comparison with SL, increased requirements for lubricants with respect to oxidation resistance, protection against deposits, wear, etc. Since October 2006, the category for diesel oils has also expanded to the class CJ-4. |
since 2004 | - |
| SL |
(Acting). The API was planning to develop the PS-06 project as the next API SK category, but one of Korea’s motor oil suppliers uses the abbreviation SK as part of its corporate name. To avoid possible confusion, the letter "K" will be skipped for the next category "S".
|
c 2001 | - |
| Sj | (Acting). The category was approved on November 6, 1995; licenses began to be issued on October 15, 1996. Automotive oils of this category are designed for all currently used gasoline engines and completely replace the oils of all previously existing categories in older engine models. The maximum level of operational properties. Possibility of certification in energy saving category API SJ / EC. | c 1996 | - |
| SH | (Conditionally acting). Licensed category approved in 1992. To date, the category is conditionally valid and can only be certified as additional to API C categories (for example, API AF-4 / SH). According to the requirements, it meets the ILSAC GF-1 category, but without mandatory energy saving. Automotive oils of this category are designed for gasoline engines of 1996 and older models. During certification of energy saving, depending on the degree of fuel economy, the categories API SH / EC and API SH / ECII were assigned. | since 1993 | higher for models since 1995 onwards |
| SG |
Licensed category approved in 1988. Licensing was discontinued at the end of 1995. Car oils are designed for engine models 1993 and older. Fuel - unleaded gasoline with oxygenates. Meet the requirements for automotive diesel oils for API CC and API CD categories. They have higher thermal and antioxidant stability, improved antiwear properties, and a reduced tendency to form deposits and sludge. API SG automotive oils replace API SF, SE, API SF / CC, and API SE / CC. |
1989-1993 | |
| SF |
Automotive oils of this category are intended for engines of 1988 models and older. Fuel is leaded gasoline. They have more effective than previous categories, antioxidant, antiwear, anti-corrosion properties and have a lower tendency to form high and low temperature deposits and slag. API SF automotive oils replace API SC, API SD, and API SE oils in older engines. |
1981-1988 | |
| SE | High-performance engines operating in harsh conditions. | 1972-1980 | higher |
| SD | Heavy-duty medium-powered engines. | 1968-1971 | average |
| SC | Heavy duty engines. | 1964-1967 | - |
| SB | Engines operating under moderate loads are used only at the request of the manufacturer. | - | - |
| SA | Light duty engines are used only at the request of the manufacturer. | - | - |
For diesel engines - oil classes on a scale of C |
|||
| Oil group | Recommended Application | Years of car production | Qualitative indicators |
| Cj-4 |
Introduced in 2006. For high-speed four-stroke engines designed to meet the 2007 exhaust gas toxicity standards on main roads. CJ-4 oils allow the use of fuels with sulfur contents up to 500 ppm (0.05% by weight). However, working with fuels in which the sulfur content exceeds 15 ppm (0.0015% by weight) may affect the performance of exhaust gas purification systems and / or oil change intervals. Oils with specification CJ-4 exceed the performance of CI-4, CI-4 Plus, CH-4, CG-4, CF-4 and can be used in engines for which oils of these classes are recommended. |
since 2006 | - |
| SI-4 |
Introduced in 2002. For high-speed four-stroke engines designed to meet exhaust emission standards in 2002. СI-4 oils allow the use of fuel with a sulfur content up to 0.5% by weight, and are also used in engines with an exhaust gas recirculation (EGR) system. Replaces CD, CE, CF-4, CG 4 and CH-4 oils. |
since 2002 | - |
| CH-4 | Introduced in 1998. For high-speed four-stroke engines that meet the exhaust emission requirements introduced in the United States since 1998. Oils CH-4 allow the use of fuel with a sulfur content up to 0.5% by weight. Can be used in place of CD, CE, CF-4 and CG-4 oils. | since 1998 | - |
| SG-4 | Introduced in 1995. For engines of high-speed diesel technology powered by fuel with a sulfur content of less than 0.5%. CG-4 oils for engines that comply with exhaust emissions requirements introduced in the United States since 1994. Replaces oils of CD, CE and CF-4 categories. | since 1995 | higher for models since 1995 |
| CF-4 | Introduced in 1990. For high-speed four-stroke diesel engines with and without turbocharging. Can be used instead of CD and CE oils. | since 1990 | higher for four-stroke engines |
| CF-2 | Introduced in 1994. Improved performance, used instead of CD-II for two-stroke engines. | since 1994 | higher for two-stroke engines |
| CF | Introduced in 1994. Oils for off-road equipment, engines with separation injection, including those operating on fuel with a sulfur content of 0.5% by weight and above. Replaces CD oil. | since 1994 | - |
| CE | Highly advanced, highly turbocharged, heavy-duty engines can be used in place of CC and CD class oils. | since 1987 | higher |
| CD | A class of oils for high-speed turbo-charged diesel engines with high specific power, operating at high speeds and at high pressures and requiring increased anti-bearing properties and preventing the formation of soot. | since 1955 | average |
| CC | High-powered engines (including those with moderate supercharging), operating in difficult conditions. | since 1961 | low |
| CB | Medium-boost naturally aspirated engines operating at increased loads of sulfur fuel. | 1949-1960 | - |
| CA | Engines operating at moderate loads on low-sulfur fuel. | 1940-1950 | - |
The API Engine Service Classification System has been developed since 1969 as a result of collaboration API ASTMand Sae. The system is fully set out in ASTM D 4485 "Standard specification for the performance properties of motor oils" (Standart Performance Specification for Performance of Engine Oils) and SAE J183 APR96 "Engine Oil Performance and Engine Service Classifications (Other than" Energy Conserving "). New high-quality a step in the development of the quality and classification of motor oils was taken in 1983-1992, when under the leadership of API and the participation of representatives of car manufacturers ( AAAMA), engines ( EMA) and technical unions ( ASTM and Sae) was created and developed "System of licensing and certification of motor oils EOLCS" (Engine Oil Licensing and Certification System, API Publication No. 1509). This system is constantly being improved. Currently, the certification of engine oils is carried out in accordance with the requirements of EOLCS and "Code of AGR" (CMA Code of Practice).
According to the API system (ASTM D 4485, SAE J183 APR96), three operational categories (three rows) of the purpose and quality of motor oils are established:
S (Service) - consists of quality categories of motor oils for gasoline engines running in chronological order. For each new generation an additional letter is assigned alphabetically:
API SA, API SB, API SC, API SD, API SE, API SF, API SG, API SH and API SJ (category SI - API is intentionally omitted to avoid confusion with the International System of Measures).
The categories API SA, API SB, API SC, API SD, API SE, API SF, API SG are now declared invalid as outdated, however, in some countries the oils of these categories are still available, the API SH category is “conditional” and may Only be used as an option, e.g. API CG-4 / SH.
The SL class was introduced in 2001 and differs from SJ in significantly better antioxidant, anti-wear, anti-foam properties, as well as lower volatility;
C (Commercial) - consists of the categories of quality and purpose of oils for diesel engines going in chronological order. For each new generation an additional letter is assigned alphabetically:
API CA, API CB, API CC, API CD, API CD-II, API CE, API CF, API CF-2, API CF-4, API CG-4 and API CH-4.
The categories API CA, API CB, API CC, API CD, API CD-II are now declared invalid as outdated, however, in some countries, oils of these categories are still available;
EC (Energy Conserving) - energy-saving oils - a new series of high-quality oils, consisting of low-viscosity, light-flowing oils that reduce fuel consumption according to the results of tests on gasoline engines.
Motor oils with low viscosity at both low and high temperatures can be certified for compliance with the API EC category of "energy-saving" oil ("Energy Conserving" Oil). Previously, energy savings were determined using the procedure of Sequence VI (Sequence VI, ASTM RR D02 1204). This technique was used to certify API SH category oils for energy saving levels (degrees): API SH / EC - 1.5% fuel economy and API SH / ECII - 2.7% fuel economy, compared to SAE 20w-30 reference oil. Roman numbers after the EU letters indicate the level of fuel economy obtained (EU II - 2.5%).
Impact of emission control systems
Universal oils for gasoline and diesel engines are indicated by two symbols of the corresponding categories: the first symbol is the main one, and the second indicates the possibility of using this oil for a different type of engine. For example, API CG-4 / SH is an oil optimized for use in diesel engines, but it can also be used in gasoline engines for which API SH category oil and below (SG, SF, SE, etc.) are prescribed.
| For gasoline engines - oil classes on the S scale | |||
| Oil group | Years of car production | Qualitative indicators | |
| SN | Introduced in October 2010. This is the last service category for gasoline powered vehicles. This new North American standard supersedes the previous SM service category, which was introduced in 2004. API SN engine oils can be used in engines requiring API SM categories and earlier S categories. API SN oils have been improved over API SM in areas of oxidative stability and control of sediment and sludge. The API also introduced a new designation, Resource Conserving, which can be used in conjunction with the SN API. The designation “Conservation Resources” replaced the previous designation “Energy Conserving”. While the “Energy Saving” designation has focused only on fuel economy, the new “Energy Saving” designation covers fuel economy, protection of exhaust gas and turbocharging systems, and compatibility with fuels containing ethanol (up to E85, i.e. with fuels containing up to 85% bioethanol). In other words, the main difference between API SN and previous API classifications is the restriction of phosphorus content for compatibility with modern exhaust gas aftertreatment systems, as well as integrated energy saving. That is, oils classified according to API SN approximately correspond to ACEA C2, C3, C4, without correction for high temperature viscosity. | since 2011 | - |
| Sm | Introduced in November 2004. Technological development trends are aimed at increasing their environmental safety, increasing maintenance intervals while maintaining reliability. Naturally, this makes its own adjustments to the process of improving engines, being reflected on the qualities of lubricants. Following these trends, in November 2004, the API classification introduced a class for motor oils for gasoline engines - SM, which implies, in comparison with SL, increased requirements for lubricants with respect to oxidation resistance, protection against deposits, wear, etc. Since October 2006, the category for diesel oils has also expanded to the class CJ-4. |
since 2004 | - |
| SL | (Acting). The API was planning to develop the PS-06 project as the next API SK category, but one of Korea’s motor oil suppliers uses the abbreviation SK as part of its corporate name. To avoid possible confusion, the letter "K" will be skipped for the next category "S". - stability of energy-saving properties; - reduced volatility; - extended drain intervals. |
c 2001 | - |
| Sj | (Acting). The category was approved on November 6, 1995; licenses began to be issued on October 15, 1996. Automotive oils of this category are designed for all currently used gasoline engines and completely replace the oils of all previously existing categories in older engine models. The maximum level of operational properties. Possibility of certification in energy saving category API SJ / EC. | c 1996 | - |
| SH | (Conditionally acting). Licensed category approved in 1992. To date, the category is conditionally valid and can only be certified as additional to API C categories (for example, API AF-4 / SH). According to the requirements, it meets the ILSAC GF-1 category, but without mandatory energy saving. Automotive oils of this category are designed for gasoline engines of 1996 and older models. During certification of energy saving, depending on the degree of fuel economy, the categories API SH / EC and API SH / ECII were assigned. | since 1993 | higher for models since 1995 onwards |
| SG | Licensed category approved in 1988. Licensing was discontinued at the end of 1995. Car oils are designed for engine models 1993 and older. Fuel - unleaded gasoline with oxygenates. Meet the requirements for automotive diesel oils for API CC and API CD categories. They have higher thermal and antioxidant stability, improved antiwear properties, and a reduced tendency to form deposits and sludge. API SG automotive oils replace API SF, SE, API SF / CC, and API SE / CC. |
1989-1993 | |
| SF | Automotive oils of this category are intended for engines of 1988 models and older. Fuel is leaded gasoline. They have more effective than previous categories, antioxidant, antiwear, anti-corrosion properties and have a lower tendency to form high and low temperature deposits and slag. API SF automotive oils replace API SC, API SD, and API SE oils in older engines. |
1981-1988 | |
| SE | High-performance engines operating in harsh conditions. | 1972-1980 | higher |
| SD | Heavy-duty medium-powered engines. | 1968-1971 | average |
| SC | Heavy duty engines. | 1964-1967 | - |
| SB | Engines operating under moderate loads are used only at the request of the manufacturer. | - | - |
| SA | Light duty engines are used only at the request of the manufacturer. | - | - |
| For diesel engines - oil classes on a scale of C | |||
| Oil group | Recommended Application | Years of car production | Qualitative indicators |
| Cj-4 | Introduced in 2006. For high-speed four-stroke engines designed to meet the 2007 exhaust gas toxicity standards on main roads. CJ-4 oils allow the use of fuels with sulfur contents up to 500 ppm (0.05% by weight). However, working with fuels in which the sulfur content exceeds 15 ppm (0.0015% by weight) may affect the performance of exhaust gas purification systems and / or oil change intervals. CJ-4 oils are recommended for engines equipped with diesel particulate filters and other exhaust gas treatment systems. Oils with specification CJ-4 exceed the performance properties of CI-4, CI-4 Plus, CH-4, CG-4, CF-4 and can be used in engines for which oils of these classes are recommended. |
since 2006 | - |
| SI-4 | Introduced in 2002. For high-speed four-stroke engines designed to meet exhaust emission standards in 2002. СI-4 oils allow the use of fuel with a sulfur content up to 0.5% by weight, and are also used in engines with an exhaust gas recirculation (EGR) system. Replaces CD, CE, CF-4, CG 4 and CH-4 oils. In 2004, the additional API CI-4 PLUS category was introduced. Stricter requirements for soot formation, deposits, viscosity indicators, limiting the value of TBN. |
since 2002 | - |
| CH-4 | Introduced in 1998. For high-speed four-stroke engines that meet the exhaust emission requirements introduced in the United States since 1998. Oils CH-4 allow the use of fuel with a sulfur content up to 0.5% by weight. Can be used in place of CD, CE, CF-4 and CG-4 oils. | since 1998 | - |
| SG-4 | Introduced in 1995. For engines of high-speed diesel technology powered by fuel with a sulfur content of less than 0.5%. CG-4 oils for engines that comply with exhaust emissions requirements introduced in the United States since 1994. Replaces oils of CD, CE and CF-4 categories. | since 1995 | higher for models since 1995 |
| CF-4 | Introduced in 1990. For high-speed four-stroke diesel engines with and without turbocharging. Can be used instead of CD and CE oils. | since 1990 | higher for four-stroke engines |
| CF-2 | Introduced in 1994. Improved performance, used instead of CD-II for two-stroke engines. | since 1994 | higher for two-stroke engines |
| CF | Introduced in 1994. Oils for off-road equipment, engines with separation injection, including those operating on fuel with a sulfur content of 0.5% by weight and above. Replaces CD oil. | since 1994 | - |
| CE | Highly advanced, highly turbocharged, heavy-duty engines can be used in place of CC and CD class oils. | since 1987 | higher |
| CD | A class of oils for high-speed turbo-charged diesel engines with high specific power, operating at high speeds and at high pressures and requiring increased anti-bearing properties and preventing the formation of soot. | since 1955 | average |
| CC | High-powered engines (including those with moderate supercharging), operating in difficult conditions. | since 1961 | low |
| CB | Medium-boost naturally aspirated engines operating at increased loads of sulfur fuel. | 1949-1960 | - |
| CA | Engines operating at moderate loads on low-sulfur fuel. | 1940-1950 | - |
Universal oils for gasoline engines and diesel engines have designations of both categories, for example API SG / CD, API SJ / CF.
Classes of diesel oils subdivided further for push pull (CD-2, CF-2) and four strokediesel engines (CF-4, CG-4, CH-4).
API Signs
Oils that meet the requirements of the current quality categories and have passed the official API - SAE tests have on their labels a graphic round sign (donut mark) - "API service symbol" ( API Service Symbol), which indicates the degree of viscosity according to SAE, the category of quality and purpose according to API and the possible degree of energy saving.
Oils licensed by the API and responding to the SN API are displayed on the back label with the API service ring symbol. The information that the licensed oil also meets the designation Resource Conserving is shown on the bottom of the ring.
The latest API certified oils, when compliant with ILSAC requirements, are identified by the “API Certification Certification Symbol” (), the so-called “Starburst” mark. This mark can only be assigned to energy-saving, light-flowing oils of the highest quality level, with viscosities SAE 0W -..., 5W -... and 10W -.... The ILSAC GF Series Oil Requirement System is part of the American Oils Quality Assurance API (EOLCS).
API - ILSAC systems are designed to meet the requirements for oils used in engines of American and Japanese cars. The requirements of European automakers are slightly different due to the design features of European engines. Despite this, most motor oils entering the European market are labeled with API quality categories and, in rare cases, even with the “API Service Symbol”.
API engine oil classification was developed in 1969. It is quite common around the world.
She marks the products of well-known manufacturers, such as Castrol, Motul, Shell. The marking indicates the type of car engine into which it is possible to fill in the oil. Its decryption is quite simple. Accordingly, with the classification of oils by API, all lubricants are divided into:
Lubricants suitable for all motors are marked with a pair of characters. The 1st symbol is considered the main, the 2nd indicates that the oil can be poured into a different kind of engine. Example: API SM / CF oils.
The API classification includes the following classes of gasoline engine oil:
API Oil Brief The API diesel engine oil may fall into one of the following categories:
It is necessary to familiarize yourself with the classification of transmission oils in order to be able to decipher the markings when choosing a lubricant for the transmission. Through the designations on the canister, it is possible to understand what are the characteristics of the product, what additives and base oils it consists of.
