||ELASTO-HYDRODYNAMIC (EHD) LUBRICATION - lubrication phenomenon occurring during elastic deformation of two non-conforming surfaces under high load. A high load carried by a small area (as between the ball and race of a rolling contact bearing) causes a temporary increase in lubrication viscosity as the lubricant is momentarily trapped between slightly deformed opposing surfaces.
ELECTRIC EMISSION CONTROL (EEC) - in automobiles, computerized operating controls reduce automotive exhaust emissions of carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC), primarily by optimizing combustion efficiency. This is accomplished by automatic monitoring and control of key engine functions and operating parameters, such as air-fuel ratio (see combustion), and exhaust gas recirculation.
ELASTOMETER - rubber or rubber-like material, both natural and synthetic, used in making a wide variety of products, such as tires, seals, hose, belting, and footwear. In oil seals, an elastometerís chemical composition is a factor in determining its compatibility with a lubricant, particularly a synthetic lubricant.
EMISSION CONTROLS - see catalytic converter, emissions (automotive), electronic emission controls, exhaust as recirculation, positive crankcase ventilation.
EMISSIONS (AUTOMOTIVE) - the three major pollutant emissions for which gasoline-powered vehicles are controlled are: unburned hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). Diesel-powered vehicles primarily emit NOx and particulates. Motor vehicles contribute only a small percentage of total man-made emissions of other atmospheric pollutants, such as sulfur oxides. Evaporative HC emissions from the fuel tank and carburetor are absorbed by activated carbon contained in a canister installed on the vehicle. Blow-by HC emissions from the crankcase are controlled by positive crankcase ventilation (PC). Exhaust emissions of HC, CO, and NOx--the products of incomplete combustion--are controlled primarily by a catalytic converter, in conjunction with exhaust gas recirculation and increasingly sophisticated technology for improving combustion efficiency, including electronic emission controls hydrocarbons emissions.
EMULSIFIER - additive that promotes the formation of a stable mixture, or emulsion, of oil and water. Common emulsifiers are: metallic soaps, certain animal and vegetable oils, and various polar compounds (having molecules that are water-soluble at one extremity of their structures and oil-soluble at the other).
ENERGY - capacity to do work. There are many forms of energy, any of which can be converted into any other form of energy. To produce electrical power in a steam turbine-generator system, the chemical energy in coal is converted into heat energy, which (through steam) is converted to the mechanical energy of the turbine, and in turn, converted into electrical energy. Electrical energy may then be converted into the mechanical energy of a vacuum cleaner, the radiant and heat energy of a light bulb, the chemical energy of a charged battery, etc. Conversion from one form of energy to another results in some energy being lost in the process (usually heat). There are two kinds of mechanical energy; kinetic energy, imparted by virtue of a bodyís motion, and potential energy, imparted by virtue of a bodyís position (e.g., a coiled spring, or a stone on the edge of a cliff). Solar (radiant) energy is the basis of all life through the process of photosynthesis, by which green plants convert solar energy into chemical energy. Nuclear energy is the result of the conversion of a small amount of the mass of an unstable (radioactive) atom into energy. The fundamental unit of energy in the Systeme International is the joule. It can be expressed in other energy units, such as the calorie, British Thermal Unit (BTU), kilowatt-hour, etc. by the use of appropriate conversion factors.
ENGINE DEPOSITS - hard or persistent accumulations of sludge, varnish, and carbonaceous residues due to blow-by of unburned and partially burned (partially oxidized) fuel, or from partial breakdown of the crankcase lubricant. Water from condensation of combustion products, carbon, residues from fuel or lubricating oil additives, dust metal particles also contribute. Engine deposits can impair engine performance and damage engine components by causing valve and ring sticking, clogging of the oil screen and oil passages, and excessive wear of pistons and cylinders. Hot, glowing deposits in the combustion chamber can also cause pre-ignition of the air-fuel mix. Engine deposits are increased by short trips in cold weather, high-temperature operation, heavy loads (such as pulling a trailer), and over-extended oil drain intervals.
ENGINE OIL (CRANKCASE OIL, MOTOR OIL) - oil carried in crankcase, sump, or oil pan of a reciprocating internal combustion engine to lubricate all major engine parts; also used in reciprocating compressors and in steam engines of crankcase design. In automotive applications, it is the function of the engine oil not only to lubricate, but to cool hot engine parts, keep the engine free of rust and deposits (see engine deposits), and seal the rings and valves against leakage of combustion gases. Oil-feed to the engine parts is generally under pressure developed by a gear pump (forced feed). The oil circulates through passages formed by tubing and drilling (rifling) through the engine parts, and through an oil filter to remove metallic contaminants and other foreign particles. In some engines, lubrication may also be accomplished in part by splashing resulting from the rotation of the crankshaft in the oil in the sump. Modern engine oils are formulated with additives to improve performance. Additive content in a single-viscosity-grade oil is typically around 15 mass percent, and in a multi-grade oil, 20 percent or more.
EP ADDITIVE - lubricant additive that prevents sliding metal surfaces from seizing under conditions of extreme pressure (EP). At the high local temperatures associated with metal-to-metal contact, an EP additive combines chemically with the metal to form a surface film that prevents the welding of opposing asperities, and the consequent scoring that is destructive to sliding surfaces under high loads. Reactive compounds of sulfur, chlorine, or phosphorus are used to form these inorganic films.
EROSION - mechanical removal of material by impingement of high velocity fluid with or without entrained particles.
ESTER - chemical compound formed by the reaction of an organic or inorganic acid with an alcohol or with another organic compound containing the hydroxyl (-OH) radical. The reaction involves replacement of the hydrogen of the acid with a hydrocarbon group. The name of the ester indicates its derivation; e.g., the ester resulting from the reaction of ethyl alcohol and ascetic acid is called ethyl acetate. Esters have important uses in the formulation of some petroleum additives and synthetic lubricants. See dibasic acid ester, phosphate ester.
ETHANOL - also known as ethyl alcohol (C2H5OH). Obtained principally from the fermentation of grains or blackstrap molasses; also obtained from ethylene, by absorption in sulfuric acid and hydrolyzing with water. Widely used as an industrial solvent, extraction medium, chemical intermediate, and in many proprietary products; a component of gasohol.
ETHYLENE - flammable gas (C2H4) derived from natural gas and petroleum; the lowest molecular weight member of the generic family of olefins. Ethylene is widely used as a feedstock in the manufacture of petrochemicals, including polyethylene and other plastics.
EXHAUST GAS RECIRCULATION (EGR) - system designed to reduce automotive exhaust emissions of nitrogen oxides (NOx). The system routes exhaust gases into the carburetor or intake manifold; the gases dilute the air-fuel mixture (see combustion) which lowers peak combustion temperatures, thus reducing the tendency for NOx to form.
EXTRACTION - use of a solvent to remove edible and commercial oils and seeds (e.g. soybeans), or oils and fats from meat scraps; also, the removal of reactive components from lube distillates. (See solvent extraction).