The most important function of lubricants is the reduction of friction and wear and the relative movement of two bearing surfaces is only possible if a lubricant is present. A Lubricant is either an oil or a grease or a solid used to reduce friction between to surfaces. Lubricants can be classified into two groups: automotive and industrial lubricants – lube oils and greases.
Engine oil viscosity classification SAE J300
The requirements of viscosity classification are determined now by SAE J300 revised in January 2015 by the Society of Automotive Engineers Inc. New York. As the vehicles of European manufacturers have a wide spread occurrence, the basic classification system is ACEA which replaced CCMC classification in 1996 . The development of lubricants is closely linked to the specific applications and application methods, the following section will consider both lubricants and their application.
The viscosity of an engine oil is an indicator of how readily a loadcarrying film can be formed at all lubrication points in an engine. As viscosity is a function of temperature, it applies to all potential ambient and operating temperatures. The first number (15W) refers to the viscosity grade at low temperatures (W from winter), whereas the second number (40) refers to the viscosity grade at high temperatures.
ACEA European Oil sequences-guideline
Three main factors specifically affecting the european market:
- Extended oil drain intervals
- Fuel savings
- Exhaust gas composition
ACEA specifications are guidelines for European cars. The different uses of the oils are labelled by the European ACEA 2012 classification by letter:
A / B - for passenger car gasoline and light duty diesel engines
C - for passenger cars gasoline and light duty diesel engines with after treatment devices
E - for commercial vehicles with heavy duty diesel engines
ACEA A / B for gasoline and diesel engine oils
ACEA C for Catalyst compatibility oils
DPF : Diesel Particulate Filter
TWC : Three way catalyst
HTHS : High temperature / High shear rate viscosity
ACEA E for Heavy Duty Diesel engine oils
API Classification have been made by AMERICAN PETROLEUM INSTITUTE API, ENGINE OIL LICENSING AND CERTIFICATION SYSTEM EOLCS.
Engine Oil Guide
1. Performance Level
Motor oils designed for cars, vans, and light trucks with gasoline engines fall under API’s “S” (Service) categories. Motor oils designed for heavy duty trucks and vehicles with diesel engines fall under API’s “C”(Commercial) categories. Please see the Gasoline Engines and Diesel Engines charts for descriptions of current and obsolete API service categories.
2. Viscosity Grade:
Measure of oil’s thickness and ability to flow at certain temperatures. Vehicle requirements may vary. Follow your vehicle manufacturer’s recommendations on SAE oil viscosity grade.
3. Resource Conserving and Energy Conserving:
These designations apply to oils intended for gasoline-engine cars, vans, and light trucks. Widespread use of “Resource Conserving” or “Energy Conserving” oils may result in an overall savings of fuel in the vehicle fleet as a whole.
4. Multiple Performance Levels:
Oils designed for diesel engine service might also meet gasoline engine service. For these oils the designation is “C” category first followed by the “S” category. “C” category oils have been formulated primarily for diesel engines and may not provide all of the performance requirements consistent with vehicle manufacturers’ recommendations for gasoline fueled engines.
Guide to SAE VISCOSITY GRADES OF ENGINE OIL for PASSENGER CARS
Multigrade oils such as SAE 5W-30 and 10W-30 are widely used because, under all but extremely hot or cold conditions, they are thin enough to flow at low temperatures and thick enough to perform satisfactorily at high temperatures. Note that vehicle requirements may vary.
Follow your vehicle manufacturer’s recommendations on SAE oil viscosity grade.
The current and previous API Service Categories are listed below. Vehicle owners should refer to their owner’s manuals before consulting these charts. Oils may have more than one performance level.
For automotive gasoline engines, the latest engine oil service category includes the performance properties of each earlier category. If an automotive owner’s manual calls for an API SJ or SL oil, an API SM oil will provide full protection. For diesel engines, the latest category usually – but not always – includes the performance properties of an earlier category.
GASOLINE ENGINES
API C DIESEL ENGINES
API EC Energy Conserving
The ILSAC (International Standardization and Approval Commitee) uses together with another American Institute and the JAMA (Japan Automobile Manufacturers Association) the API Classifikationen for an individual ILSAC Standard: