Tribologie E

Emcor Test
This Emcor process is used to test what protection lubricating greases in roller contact bearings, plain bearings and sliding surfaces provide for the material in the presence of water, under conditions that are as close to actual operating conditions as possible. DIN 51 802.
 

Emissions
Contaminants discharged into the atmosphere from chimneys, exhaust systems, etc. and cause air pollution.
 

Emulsifiability
The propensity of a synthetic or mineral oil or a compounded oil to form an emulsion with water.

Emulsifiers
Fatty acids, grease soaps, ammonium salts, sulphonic acids, naphthenic acids, etc.; they are classified as anionic, cationic and non-ionizing emulsifiers. Emulsifiers are surface-active substances which promote the formation and stability of an emulsion through reducing the surface tension of water. A distinction is made between oil-in-water emulsions (most common) and water-in-oil emulsions.
 

Emulsion
Mixture of non-soluble substances; mineral oil with water, for instance, with the help of emulsifiers; it generally takes the form of oil-in-water emulsion but it may possibly also be a water-in-oil emulsion.
 

Engine oil
This is used to lubricate bearings, engines, cylinders and the valve timing gears in vehicles with internal combustion engines. Engine oils are classified into various viscosity grades (SAE classifications); there are compounded and non-compounded engine oils which, depending on their compounding grade, satisfy various specifications (e.g. MIL, ACEA) and classifications (e.g. API).
 

Engler (E)
Conventional measure to indicate viscosity, what is measured is the efflux time of an oil from a certain flask; the ratio between the relative oil efflux time to the water efflux time at 20°C is the Engler degree.
 

EP lubricants
Extreme Pressure lubricants; in the case of lubricating oils or lubricating greases which contain EP active ingredients (polar or metal-active additives or solid lubricants, etc.) in order to allow higher loads to be absorbed, e.g. in engine, gear (hypoid), hydraulic, cutting oils, etc.
 

Ester
Compounds formed by the bonding of acids and alcohols and by the elimination of water (aldol condensation or oxo synthesis). Higher-alcohol esters with bivalent fatty acids form what are termed ester oils; synthetic lubricating oils which, depending on their type, have certain advantages over mineral lubricating oils.
 

Extreme Pressure (EP) high-pressure additives
Organic phosphate, chlorine, sulphur and nitrogen compounds, etc., to allow higher loads to be absorbed and to reduce wear in mixed friction areas. Additives called EP additives are added to oils such as gear, engine, hydraulic and cutting oils. These prevent wear and improve the sliding properties of metal surfaces that move against each other.