Glossary of Terms 2T/2-cycle A term applied to lubricants designed for 2-cycle engines (i.e., motorcycles, outboard marine motors, weed whackers, etc.). 4T A term applied to lubricants designed for four-cycle engines. AAMA American Automobile Manufacturers Association ABOT Aluminum Beaker Oxidation Test required for Ford Mercon ATF approval. ACC American Chemistry Council ACS American Chemical Society Abrasion A result of inadequate or improper lubrication. The removal or general wearing away of a surface through contact with a rough material. Can be caused by the presence of foreign matter such as dirt, grit, or metallic particles in your lubricant. Can cause the break down of the material such as the tooth surfaces of gears. Additive A chemical compound or formulation of several chemical compounds added to a base oil to alter its physical, chemical, and/or performance properties. AGMA American Gear Manufacturers Association AMA Automobile Manufacturers Association ANSI American National Standards Institute Antioxidant A chemical component added to lubricants to reduce the tendency for oxidation-related degradation of the oil. Antiwear Additive An additive in a lubricant that reduces friction and wear. These generally function by creating sacrificial films on metal surfaces that prevent detrimental contact between rubbing metal surfaces. AO Antioxidant API American Petroleum Institute; a society organized to further the interest of the petroleum industry. API GL-4 Designates the type of service characteristic of gears, particularly hypoid gears in passenger cars and other automotive-type equipment operated under high-speed, low-torque and low-speed, high-torque conditions; largely replaced by performance standard, API GL-5 API GL-5 Designates the type of service characteristic of gears, particularly hypoid gears in passenger cars and other automotive type equipment operated under high-speed, shock load; high-speed, low-torque; and low-speed, high-torque conditions. Ashless Additive An additive containing no metallic elements. ASLE American Society of Lubrication Engineers (now STLE) Asperities Microscopic projections on metal surfaces resulting from normal metal finishing processes. ASTM American Society for Testing and Materials ATF Automatic Transmission Fluid AW Antiwear agent. Minimizes wear by reacting with a metal surface to provide a protective layer. Base Stock A refined petroleum fraction, usually lubricating oil, into which additives and other products are blended to produce a finished product. Bearing A basic machine component designed to reduce friction between moving parts and to support a moving load. Biodegradable A biodegradable substance can be chemically decomposed (broken down to simpler components) by natural biological processes (e.g. soil bacteria, weather, plants, animals). BOCLE Ball On Cylinder Lubricity Evaluator Boiling Point The temperature at which a liquid changes to a gas (vapor) at normal atmospheric pressure. Boundary Lubrication A regime of lubrication where there is partial contact between lubricated metal components and partial separation of these components by a lubricating film. Brookfield Viscosity A measure of the viscosity characteristics of a lubricant under low temperature and low shear conditions. Measured in centipoise, it is the apparent viscosity determined by the test method ASTM D 2983 and measured using a Brookfield viscometer. The operating principle for the Brookfield viscometer is the torque resistance on a spindle rotating in the fluid being tested. Brookfield viscosities are most frequently associated with low temperature properties of gear oils and transmission fluids but extend to many other types of lubricant. BSFC Brake-Specific Fuel Consumption BTU British Thermal Units Bypass Filtration A system of filtration in which only a portion of the total flow of a circulating fluid system passes through a filter at any instant or in which a filter having its own circulating pump operates in parallel to the main flow. C-3 A specification by the Allison Division of General Motors that covers transmission application. C-4 An updated specification by the Allison Division of General Motors that covers transmission application. Catalyst A substance that contributes to a chemical reaction without undergoing any change. CCS Cold Cranking Simulator (ASTM D 5293) Cellulose Media A filter material made from plant fibers. Because cellulose is a natural material, its fibers are rough in texture and vary in size and shape. Compared to synthetic media, these characteristics create a higher restriction to the flow of fluids. CFPP Cold Filter Plugging Point CI Cetane Index Cloud point The temperature at which a lubricant appears cloudy or hazy due to the formation of wax crystals in a sample that is cooled under standard conditions. CN Cetane Number CO Carbon monoxide CO2 Carbon dioxide Combustible The U.S. Occupational Health and Safety Administration (OSHA) defines a combustible liquid as "any liquid having a flash point at or above 100 deg. F (37.8 deg. C), but below 200 deg. F (93.3 deg. C), except any mixture having components with flashpoints of 200 deg. F (93.3 deg. C), or higher, the total volume of which make up 99 percent or more of the total volume of the mixture.” Consistency A basic property describing the hardness or softness of a grease. The consistency of a grease depends on the base oil viscosity and the type and proportion of thickener used in its formation. Consistency is usually measure by the cone penetration test ASTM D 217. Corrosion The decay and loss of a metal due to a chemical reaction between the metal and its environment. It is a transformation process in which the metal passes from its elemental form to a combined (or compound) form. Corrosion Inhibitor A additive that protects lubricated metal surfaces from against the corrosive chemicals attack of water, acids and other contaminants. cP Centipoise = mPa • s (SI unit) cSt Centistokes CVT Continuously Variable Transmission Demulsibility A measure of the ability of an oil to separate water. This is measured according to the time required for a specified oil−water mixture to break up using ASTM D 1401. Density The mass of a unit volume of a substance. The density of a material varies with the temperature of the material. Several units can be used for density. Detergent An oil additive that prevents deposits from forming on engine surfaces and that may remove previously formed deposits. Some detergents can neutralize acids formed by the combustion process. A detergent is usually a metallic compound and therefore leaves behind an ash when the oil is burned. DIN Deutsches Institut für Normung (German Standards Institute) Dispersant An oil additive that keeps engines clean by holding in suspension the insoluble products for oil oxidation and fuel combustion formed during engine operation. These are non-metallic compounds that do not produce ash in your engine. DOT Department of Transportation (U.S.) DPMA Dispersant Polymethacrylate Viscosity Modifier Dropping Point The temperature at which a grease changes from a semisolid to a liquid under the test conditions. This temperature can be considered a measure of the upper use limit for the grease. EGR Exhaust Gas Recirculation EHD Elastohydrodynamic (lubrication); occurs during the elastic deformation of two non-conforming surfaces under high loads. Generally occurs when loads are carried over a very small area. Emulsion A mechanical mixture of two mutually insoluble fluids. Some metal working fluids are designed to remain as a stable emulsion by incorporation of an emulsifier. EP Additive Extreme Pressure Additive; an additive designed to prevent metal–metal adhesion or welding when the degree of surface contact is sufficiently high that normal protective lubricating films are ineffective. EP additives function by reacting chemically with the metal surface to form a very strong surface films, e.g., iron sulfide. EPA Environmental Protection Agency (U.S.) ESI Extended Service, Internal Fire Point ASTM D 92; a laboratory test that measures the lowest temperature at which a sample will catch fire and sustain burning for five seconds. Flammable The U.S. Occupational Health and Safety Administration (OSHA) defines a flammable liquid as "any liquid having a flash point below 100 deg. F. (37.8 deg. C.), except any mixture having components with flash points of 100 deg. F. (37.8 deg. C.) or higher, the total of which make up 99 percent or more of the total volume of the mixture. Flammable liquids shall be known as Class I liquids." Flash Point ASTM D 92; a laboratory test that measures the tendency of a sample to form a flammable mixture with air, the lowest temperature at which a test flame causes the vapor of a fluid to ignite instantaneously. Four Ball Test Two test procedures based on the same principle: 1. Four-Ball EP Test (ASTM D 2596) - three lower balls are clamped together to form a cradle upon which a fourth ball rotates about its vertical axis. The balls are immersed in the lubricant under investigation. The test is used to determine the relative wear-preventing properties of lubricants operating under boundary lubrication conditions. The test is carried out at a specified speed, temperature, and load. At the end of the specified period, the average diameter of the wear scars on the three balls is reported. 2. Four-Ball Wear Test (ASTM D 2266) - evaluates performance under much higher loads. In this test, the top ball is rotated at a specified speed (1700 ± 60rpm), but temperature is not controlled. The loading is increased at specified intervals until the rotating ball seizes and welds to the other balls. At the end of each interval the average scar diameter is recorded. Two values are generally reported - load wear index and weld point. Friction The resistance of the motion of one surface over another. The amount of friction depends on the smoothness of the contacting surfaces and the force that presses them together. HFRR High-Frequency Reciprocating Rig (ASTM D6079); standard test method that measures the lubricity of diesel fuels. HD Hydrodynamic (lubrication); a lubrication regime wherein a full fluid film lubricates two moving surfaces. Generally occurs when loads are carried over a large surface area. IR Infrared (spectroscopy); identifies organic functional groups present in oil using their absorption of light. ISO International Standards Organization ISO 4406 ISO Cleanliness Code System; a method that measures the number of particles per unit volume that are greater than 2 microns (optional), 5 microns and 15 microns in size. Enables easy evaluation of system and filter performance. KV Kinematic Viscosity (cSt); a measure of viscosity derived from the time taken for a fixed volume of oil to flow through a capillary tube. LB In the ASTM D 4950 Standard Classification and Specification for Automotive Service Greases, the letters LB designate service typical for the lubrication of chassis components and universal joints in passenger cars, trucks, and other vehicles under mild to severe duty. Load Wear Index Measures the relative ability of a lubricant to prevent wear; it is calculated using the Four Ball EP test. LSD Low-Sulfur Diesel Lubricity The ability of an oil or grease to lubricate; also called film strength. Mineral Oil Any petroleum oil, as contrasted to animal or vegetable oils and synthetic fluids. Miscible Capable of being mixed in any concentration without separation of the phases. MSDS Material Safety Data Sheets Naphthenic Petroleum fluids derived from petroleum naphtha, characterized by the high content of cyclic and aromatic hydrocarbon structures and by an absence of wax molecules. Nitration Nitration products are formed during the fuel combustion process in internal combustion engines. Most nitration products are formed when an excess of oxygen is present. These products are highly acidic, form deposits in combustion areas and rapidly accelerate oxidation. NLGI National Lubricating Grease Institute NOX Nitrogen Oxides NRC Natural Resources Canada OEM Original Equipment Manufacturer (e.g., GM, Ford, etc.) OSHA Occupational Safety and Health Administration (U.S.) Oxidation The chemical combination of a substance with oxygen. All oils are subjected to oxidative process that result in their degradation. Oxidation is accelerated by heat, light, water, acids, catalysts and other solid contaminants. PAG Poly Alkene Glycols, Polyalkylene Glycols PAH Polyaromatic Hydrocarbons PAO Polyalphaolefins; base stocks of various viscosity classifications. Paraffinic Petroleum fluids consisting of hydrocarbons that are characterized by straight or branched carbon chains; also called alkanes. Particulates Particles made up of a wide variety of natural materials and man-made pollutants. PIB Polyisobutene Poise The unit of absolute viscosity (dyne-sec/cm2) as measured by the shear stress required to move one layer of fluid along another over a total thickness of 1 cm at a shear rate of 1 cm/sec. Absolute viscosity values are independent of density and are directly related to the resistance to flow. Pour Point ASTM D97; the lowest temperature at which an oil will flow when cooled under prescribed conditions. This widely used low-temperature flow indicator is significant for cold weather start-ups and a conventional measure of the low temperature limit for operation. The cold temperature performance properties of an oil also strongly depend on its cloud point and low temperature pumpability or fluidity. PM Particulate Matter PMA Polymethacrylate; viscosity index improvers or viscosity modifiers. PPD Pour Point Depressant; an additive used to lower the pour point of an oil by modifying the structure or chemistry of wax molecules. ppm parts per million RBOT Rotating Bomb Oxidation Test Refining A series of processes that convert crude oil into finished petroleum products. R&O Rust and Oxidation SAE Society of Automotive Engineers Scoring Distress marks (scratches) found on sliding metal surfaces. Scoring is an advanced stage of scuffing. Scuffing Localized distress marks found on sliding metal surfaces. Shearing When two surface layers move with respect to one another, they experience shearing due to the frictional forces that exist between them that prevent motion. Sludge Insoluble material formed from the deterioration of an oil, its contamination, or both. Solvent A material with a strong capability to dissolve a given substance. Spectrographic Analysis A techniques for detecting and quantifying metallic elements in an oil resulting from wear, contamination or additives. SSU or SUS Saybolt Second Universal or Saybolt Universal Second; a measure of viscosity, or a fluid’s resistance to flow. STLE Society of Tribologists and Lubrication Engineers Synthetic Lubricating fluids made by chemically reacting materials of a specific chemical compound to produce a product with planned and predictable properties. Synthetic lubricants are often superior to petroleum oils in specific performance areas. Many exhibit higher viscosity index, better thermal stability, oxidative stability and lower volatility. Total Acid Number (TAN); the quantity of base, expressed in milligrams of potassium hydroxide, that is required to neutralize all acidic constituents present in 1 gram of sample. (ASTM Designation D 974) Also known as the neutralization number, this quantifies the amount of acid in your oil. Total Base Number (TBN); the quantity of acid, expressed in terms of the equivalent number of milligrams of potassium hydroxide that is required to neutralize all basic constituents present in 1 gram of sample. (ASTM Designation D 974) This quantifies the amount of alkaline reserve in your oil that will neutralize acids produced during oil degradation processes. Timken OK load This is a measure of the extreme-pressure properties of a lubricant according to ASTM D2509 and D2782. Lubricated by the product under investigation, a standard steel roller rotates against a stationary block. The Timken OK load is the heaviest load that can be carried by the roller before scoring occurs. Tribology The science and technology of interacting surfaces in relative motion and the practices related to lubrication, friction and wear. Varnish When applied to lubrication, a hard coating or deposit that bakes onto interior parts due to the oxidation and polymerization of fuels and lubricants. Varnishes can accelerate wear by causing close-clearance moving parts to stick and malfunction. VI Viscosity Index; a measure of the rate of change in viscosity with temperature (higher VI means less change). (ASTM D 2270) VII Viscosity Index Improver; an additive that increases the viscosity index beyond that which can be obtained using ordinary refining methods. Viscosity A measure of a fluid’s resistance to flow. Dynamic viscosity is the ratio between the applied shear and the rate of shear, expressed in poise or centipoise. Kinematic viscosity is the ratio of the viscosity (dynamic viscosity) to the density of the liquid, expressed in stokes or centistokes. Wear The abrasion or rubbing away of the surface of a material as a result of mechanical action. Weld Point The lowest applied load in the Four Ball EP test at which the rotating ball seizes to the three stationary balls and stops rotating or at which extreme scoring of the three balls results. ZDDP Zinc Dialkyldithiophosphate; a widely used antiwear agent and antioxidant for motor oils and industrial fluids. It is also referred to as ZDTP, ZDP, and “zinc”.