Automotive Lubricants Oils

The lubricating oils can be of animal or plant origin (oils), derived from petroleum (oil) or produced in the laboratory (synthetic oils), can still be made by mixing two or more types (oil compounds).

The main characteristics of lubricating oils are the viscosity, the index of viscosity (IV) and density.

The viscosity measures the difficulty with which the oil flows (seeps), the more viscous is a lubricant (thicker), more difficult to drain, so will be greater its ability to sustain themselves between two moving parts making the lubrication of them.

Density indicates the weight of a certain quantity of oil to a certain temperature, it is important to indicate whether there was contamination or deterioration of a lubricant.

To give them some special properties or improve some existing, but in insufficient degree, especially when the lubricant is subjected to severe conditions of work, chemicals are added to lubricating oils, which are called additives.

The main types of additives are: anti-oxidants, anti-corrosive, anti-rust, anti-sparkling, detergent-dispersant, improvement of the Index of viscosity, agents of extreme pressure and so on.

Oils for engines - Ratings

To facilitate the choice of the correct lubricant for automotive vehicles are the various classifications, with the main SAE and API.

SAE Classification:

Established by the Society of Automotive Engineers of the United States, classifies the lubricating oil for its viscosity, which is indicated by a number. The higher this number, more viscous is the lubricant and are divided into three categories:

* Oils of summer: SAE 20, 30, 40, 50, 60
* Oils Winter: SAE 0W, 5W, 10W, 15W, 20W, 25W
* Oils multiviscosos (winter and summer): SAE 20W-40, 20W-50, 15W-50

Note: the letter "W" comes from the English "winter" that means winter.

Viscosity of oil

As tenacity or viscosity of liquid is understood that the resistance
the molecules in a liquid form against a shift. This resistance
is also called internal friction.

* Kinematic viscosity

Viscosity ratio / density indicated in mm2 / s (formerly centistoke).

* Viscosity dynamic

It is a measure of internal resistance that the lubricating oil as against the flow
(for example, flow through pipelines, flow in the slit of lubrication).
The visc.dinâmica is denominated in Centipoise (cp).

To measure the viscosities have various parts of measurement (viscosímetros).
The indication is in mm2 / s, was formerly used Engler degrees (° E);
Centistokes (CST).

There are other institutes of classification than the NCS, the AGMA and ISO VG.

Classification API:

Developed by the American Institute of Petroleum, also of the United States, based on levels of performance of lubricating oil, that is, the type of service that the machine is subject. They are classified in two letters, basically indicates the first type of fuel the engine and the second type of service.

For drivers of light vehicles (Otto cycle) the "S" of Service Station (Department of Posts, Garage) or Spark (Faísca / Centelha), and another bill defines the performance.

The oil is higher than the SJ HS, namely SJ happening in all the tests that the oil HS passes, and in others that the HS not passa.O oil HS in turn is higher than the GS, so forth.

The first level was the API SA, obsolete for a long time, consisting of a pure mineral oil, without any aditivação.

In the case of diesel, the classification is API CI-4, CG-4, CF-4, CF, EC, etc.. The "C" for Commercial (Business Line, Fleet), or Compression (Compression).

The API also classifies oils for two-stroke engines and oils for transmission and gears.

The lubricating oil to gasoline engines 2 stroke, such as those used in CHAINSAWS, covering 3 levels of performance: API TA, TB and TC.

The American Petroleum Institute (API) sets the parameters for performance, through a series of complex and specific tests, according to standardized methods by ASTM (American Society for Testing and Materials).

The API is not the only body that approves testing and lubricants, we have also:

* ACEA: Association of Constructors of European Automobiles;
* ILSAC: International Lubricant Standardisation & Approval Committee,
* Assembly: manufacturers of vehicles and engines have also developed their own tests and specifications for lubricants.

The evaluation of performance of lubricants is a sequence of field tests in laboratories and engines. The sequence of tests determines patterns of conditions that the internal components of the engine should make after running with the lubricant is testing.

* Evolution of the Service Station or Spark classification:

1. SA, SB, SC, SD Created from the 30, are currently obsolete.
2. SE Established in 1972, specification of service typical of a gasoline engine vehicles, light trucks and some models 1971 to 1979.
3. SF Founded in 1980, specification of service typical of a gasoline engine vehicles, light trucks and some models 1980 to 1989. It provides greater stability to oxidation.
4. SG Created in 1989, specification of service typical of a gasoline engine for light vehicles, vans and trucks that require this specification. It provides more control of deposits in the engine and stability to oxidation.
5. HS Created in 1992, specification of service typical for use in a gasoline engine for light vehicles, vans and trucks that require this specification. Outperform the specifications earlier in control of deposits, oil oxidation, wear and corrosion.
6. SJ Established in 1996, specification of service typical of a gasoline engine for light vehicles, vans and trucks that require this specification. Outperform and supersedes all previous specifications.

* Evolution of classification or Commercial Compression:

Important: The ratings "C" went through various tests and not necessarily replace / exceed one the other classifications such as "S". Then note that not all outweigh the other one and caution in the application.

Description of Category

1. CA, CB Created from the early 40, are currently obsolete.
2. DC Created in 1961 for use in engines in moderate conditions of service.
3. CD Created in 1955, for use in aspirated engines or turbinados in conditions of heavy lifting.
4. EC Founded in 1983, service typical of diesel turbinados in conditions of heavy lifting.
5. CF Created in 1994, for use in or turbinados aspirated engines using diesel with high sulphur content.
6. CF-4 Created in 1990, service typical of diesel light vehicles, and trucks into service extra-heavy. Outperform all previous levels.
7. CG-4 Created in 1994, this category of service is suitable for light diesel vehicles in applications inside and outside of the road. Outperform all previous levels.
8. CH-4 Created in 1994, this category of service provides better control of soot or turbinados aspirated engines using diesel with high sulphur content in applications inside and outside of the road. Outperform all previous levels

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