Engine Oil Licensing and Certification System (EOLCS)

API發動機油許可和認證系統(EOLCS)是一項自願許可和認證計劃,授權滿足特定要求的發動機油銷售商使用API發動機油品質量標誌 - API服務符號“Donut”和認證標誌“Stardust”。該計劃是石油工業,汽車和發動機製造商福特,通用汽車和戴姆勒 - 克萊斯勒的合作項目;日本汽車製造商協會;和發動機製造商協會。性能要求,測試方法和限制由汽車和發動機製造商,汽車工程師協會(SAE)和美國材料試驗學會(ASTM)以及美國化學理事會和API等行業協會等技術協會共同確定。滿足這些要求的油是由汽車製造商推薦的。

The API Service Symbol

The API Service Symbol "Donut" is divided into three parts:

  • The top half describes the oil's performance level.

  • The center identifies the oil's viscosity.

  • The bottom half tells whether the oil has demonstrated energy-conserving properties in a standard test in comparison to a reference oil.

  • Performance Levels

    The top of the Donut shows the oil's performance level for gasoline and/or diesel engines. The letter "S" followed by another letter (for example, SM) refers to oil suitable for gasoline engines. The letter "C" followed by another letter and/or number (for example, CJ-4) refers to oil suitable for diesel engines. These letters officially stand for "Service" and "Commercial." The current API performance categories that can appear in the top part of the Donut are listed in the API Service Category Chart.

  • SAE Viscosity Grade

    The center of the Donut shows the oil's SAE viscosity grade. Viscosity is a measure of an oil's flow characteristics, or thickness, at certain temperatures.

    The low-temperature viscosity (the first number, 5W in a 5W-30 oil) indicates how quickly an engine will crank in winter and how well the oil will flow to lubricate critical engine parts at low temperatures. The lower the number the more easily the engine will start in cold weather.

    The high-temperature viscosity (the second number, 30 in a 5W-30 oil) provides thickness, or body, for good lubrication at operating temperatures.

    A multigrade oil (for example, SAE 5W-30) provides good flow capability for cold weather but still retains thickness for high-temperature lubrication.

    A single grade oil (a single number in the center of the donut) is recommended for use under a much narrower set of temperature conditions than multigrade oils.

    Operators should refer to their owner's manuals to select the proper viscosity oil for the ambient temperature and operating conditions at which the equipment will be used.

  • Energy Conserving Designation

    The bottom of the donut tells whether the oil has energy conserving properties when compared with a reference oil in an engine test. Oils labeled as "Energy Conserving" have passed this test. Widespread use of engine oils with this designation should result in an overall saving of fuel in the vehicle fleet as a whole, but a particular vehicle operator may not experience a fuel savings as a result of using these oils.