- This list is certainly not intended to be a comprehensive
list of all terms and definitions in the industry. It is merely
intended to cover some of the most common lingo. If you feel
anything should be added to this list (or changed), please contact us with your suggestions.
Abrasion - Wearing, grinding, or rubbing away by friction.
Abrasion is usually due to the presence of foreign matter such
as dirt, grit, or metallic particles in the lubricant.
Absolute Viscosity - The product of Kinematics Viscosity
and Density.
Absolute Viscosity =Kinematic Viscosity x Density
Acid - Corrosive solution formed by the combination
of hydrogen and oxygen atoms with metal or metallic radicals.
Acidic solutions may be neutralized with a base or alkaline solution.
Additive - Material added to a base stock to change
its properties, characteristics or performance.
Adhesion - The property of a lubricant that causes
it to cling or adhere to a solid surface. Wear occurring when
surfaces contact, weld together and shear off.
AGMA - American Gear Manufacturer's Association. Set
viscosity and performance standards for gear lubricants.
Air Entrainment - The incorporation of air in the form
of bubbles dispersed in a fluid. Common when an improper amount
of antifoam agent is added to reduce foaming.
Air Entrapment - Small bubbles that form that cannot
disperse in a fluid.
Ambient Temperature - Temperature of the air surrounding
the point of application.
Anhydrous - Free of water.
Antifoam - Additive used to suppress the foaming tendency
of lubricants in service. Improper amounts of antifoam will lead
to air entrapment which also leads to lubrication problems.
Antifreeze - Solution in an engine cooling system that
lowers the coolant's freezing point and raises its boiling point.
Antiwear - Additives which form thin tenacious films on
loaded parts to prevent metal-to-metal contact.
API - American Petroleum Institute is a group of companies
in petroleum and related fields.
Apparent Viscosity - The viscosity determined by using
instruments such as the Cold Cranking Simulator (CCS), Mini Rotary
Viscometer (MRV) and High Temperature/High Shear. Viscosity is
expressed in units of centipoise (cP).
Ash - Metallic deposits formed in the combustion chamber
and other engine parts during high temperature operation.
Ash (Sulfated) - The ash content of an oil, determined
by charring the oil, treating the residue with sulfuric acid,
and evaporating to dryness. Expressed as % per mass.
ASLE - American Society of Lubrication Engineers.
Asperities - Hills and valleys of metal surfaces.
ASTM - American Society of Testing and Materials.
Autoignition Point - Temperature at which an
oil will ignite without a source of ignition.
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Ball Bearing - A rolling type of bearing containing
rolling elements in the form of balls.
Base Stock - The base fluid, usually a refined petroleum
fraction or a selected synthetic material, into which additives
are blended to produce finished lubricants.
Bases - Compounds that read with acids to form salts
plus water. Alkalis are water soluble bases used in petroleum
refining to remove acidic impurities. Oil soluble bases are included
in lubricating oil additives to neutralize acids formed during
the combustion of fuel or oxidation of the lubricant.
Bearing - An object that supports weight and reduces friction.
Biodegradable - A material is said to be biodegradable
when it can be broken down, within given parameters of time and
environment, by naturally occurring bacterial into simple substances
which do not harm the environment.
Blow-by - Passage of unburned fuel and combustion gases
past the piston rings of internal combustion engines, resulting
in fuel dilution and contamination of the crankcase oil.
Boundary Lubrication - Lubrication between two rubbing
surfaces without the development of a full fluid lubricating
film. It occurs under high loads and requires the use of antiwear
or extreme-pressure additives to prevent wear.
Bright Stock - A heavy residual type of lubricant base
stock characterized by Iow pour point and high viscosity index
(VI). Its use promotes a reduction in scuffing and a reduction
in oil consumption.
BTU - British Thermal Unit, a unit of energy.
By Pass---An alternate path for a flow of gas or liquid.
By Pass 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.
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Carbon Residue - Coked material remaining after an
oil has been subjected to high temperatures.
Cavitation - Formation of a void due to reduced pressure
in a lubricating grease dispensing system.
Centipoise - Unit of apparent viscosity.
Centistoke (cSt) - Unit of Kinematic Viscosity.
Cetane Number - Measure of ignition quality of a diesel
fuel. The higher the Cetane Number, the easier a high-speed,
direct injection engine will start, and the less "white
smoking" and "diesel knock" after start up.
Cetane Number Improver - An additive that boosts the
Cetane Number of a fuel.
Chain Stopper - See Oxidation Inhibitor.
Channel Point - See pour point. As you reduce the temperature
of an oil toward the pour point, you reach a point where you
can run your finger through an oil and it will not fill in the
trench you leave in the oil. Example: the gearing in the rear
end of a car Although the gears might move, the gear oil will
not flow back into the gear to lubricate it readily.
Chemical Stability - The tendency of a substance or
mixture to resist chemical change.
Cleveland Open Cup (C.O.C.) - An apparatus used to
determine the flash and fire points of petroleum products other
than fuel oils and those having an open cup flash below 79°C
(175°F).
Cloud Point - The temperature at which a cloud of wax
crystals appears when a lubricant or distillate fuel is cooled
under standard conditions. Indicates the tendency of the material
to plug filters or small orifices under cold weather conditions.
Coefficient of Friction - Number obtained by dividing
the friction force resisting motion between two bodies by the
normal force pressing the bodies together.
Cohesion - That property of a substance that causes
it to resist being pulled apart by mechanical means.
Cold Cranking Simulator (C.C.S.) - An intermediate
shear rate viscometer that predicts the ability of an oil to
permit a satisfactory cranking speed to be developed in a cold
engine.
Combustion Chamber - The space between the piston and
cylinder head in an internal combustion engine where the charge
of fuel plus air is burned to produce power.
Compatibility - A lubricant's ability to be mixed with
another lubricant without detriment to either lubricant. Also,
the ability to come into contact with other components or materials
without detrimental effects.
Compound - Substance formed by the combination of two
or more elements with differing physical and chemical properties
than the combining elements.
Compression Ignition - Ignition of fuel by the heat
generated in compressing the air charge, as in the diesel engine.
Condensation - Water vapors that form from moist air.
Consistency - The degree to which a semi-solid material
such as grease resists deformation.
Coolant - Fluid used to remove heat.
Copper Strip Corrosion - Qualitative measure of the
tendency of a liquid to corrode pure copper.
Corrosion - Destruction of a metal by chemical or electro-chemical
reaction with its environment.
Corrosion Inhibitor - Additive that protects lubricated
metal surfaces from chemical attack by water or other contaminants.
Cracking - Refining process in which large molecules
are broken down into smaller molecules. Cracking takes place
to some extent whenever high molecular material is heated strongly,
but is increased by catalysts.
Crankcase - The housing in which the crankshaft and
many other parts of the engine operate. On a two-cycle engine,
the area in which the fuel/oil mixture is drawn before being
transferred to the cylinder.
Crankcase Dilution - When unburned fuel finds its way
past the piston rings into the crankcase oil, where it dilutes
or thins out the engine lubricating oil.
Crude Oil - Naturally occurring petroleum, before any
refining or treatment.
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Defoamant - Additive used to allow air in the oil to
escape more rapidly. All oils will "foam", but an oil
that does not release the air readily, is said to "foam".
Demulsibility - The ability of an oil to separate from
water upon standing.
Density - Mass per unit of volume.
Detergent - Additive to keep engine parts clean. In
motor oil formulations, the most commonly Used detergents are
metallic soaps with a reserve of basicity to neutralize acids
formed during combustion.
Detonation - Uncontrolled burning of the last portion
(end gas) of the air/fuel mixture in the cylinder of a spark-ignition
engine. Also know as "knock" or "ping".
Dewaxing - Removal of wax from a base oil in order
to reduce the pour point.
Differential - Set of gears which transfers the power
from the drive shaft to the drive wheels and allows those wells
to turn at different speeds.
Dilution of Engine Oil--See Crankcase Dilution.
Dispersant - Additive that helps keep solid contaminants
in a crankcase oil in colloidal suspension, preventing sludge
and varnish deposits on engine parts. Usually nonmetallic "ashless",
and used in conjunction with detergents.
Distillation - Separation of a mixture of liquids with
different boiling points by progressively raising the temperature.
In a refinery distillation unit the temperature rises continuously
from the top to the bottom of the column and different fractions
or cuts are drawn off at different heights.
Distillation Test - The basic test used to characterize
the volatility of a gasoline or distillate fuel.
Drag - Resistance to movement caused by oil viscosity.
Dropping Point - Temperature at which a grease passes
{Tom a semi-solid to a liquid state under specified test conditions.
Drum - A cylindrical container which holds 55 gallons
of oil or approximately 400 pounds of grease type products. There
are also half-size drums which holds approximately 30 gallons
of oil.
Dynamic Viscosity - Viscosity of a liquid as measured
in a rotational instrument, as distinct from the kinematic viscosity
where the liquid falls through a capillary tube under its own
weight.
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E.G.R. (Exhaust Gas Recirculation) Valve - System to
reduce automotive emission of nitrogen oxides (Nox). It routes
exhaust gases into the intake manifold where they dilute the
air/fuel mixture and reduce peak combustion temperatures, thereby
reducing the tendency for Nox to form.
Elastohydrodynamic Lubrication (EHD or EHL) - Lubrication
characterized by high unit loads and high speeds in rolling elements
where the mating parts deform elastically due to the incompressibility
of the lubricant film under very high pressure.
Elastomer - A rubbery type of material.
Emissions - Term used generically to refer to the various
components of the engine's exhaust.
Emulsifier - Substance used to promote or aid the emulsification
of two liquids and to enhance the stability of the emulsion.
Emulsion - Mixture of two liquids which are not soluble
with each other, i.e., oil-in-water cutting. Water-in-oil is
classified as an inverted emulsion.
Engine Deposits - Hard or persistent accumulation of sludge,
varnish and carbonaceous residues due to blow-by of unburned
and partially burned fuel, or the partial breakdown of the crankcase
lubricant. Water from the condensation of combustion products,
glycol, carbon, residues from fuel or lubricating oil additives,
dust and metal particles also contribute.
Entrainment - Dispersion of a solid, liquid or gas
in a fluid without solution.
EP (Extreme Pressure) - Lubrication regime where surfaces
are sliding against each other under heavy load. The expression
was coined for the condition present in hypoid gears in automotive
rear axles.
EP (Extreme Pressure) Lubricants - Lubricants that
impart to rubbing surfaces the ability of carrying greater loads
than would be possible with ordinary lubricants without excessive
wear or damage.
Ester - An organic compound formed by the reaction
of an acid (organic or inorganic) with an alcohol.
Ethanol - Ethyl alcohol mainly formed through fermentation.
(Alcoholic drinks, component in "gasohol")
Ethylene Glycol - A colorless, syrupy liquid, used
as an antifreeze in cooling and heating systems.
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Feedability - The ability of the lubricating grease
to flow to the suction of a dispensing pump at the rate equal
to the pump delivery capacity.
Fillers - A term normally used to denote something
nonchemical added to an oil or grease, i.e., moly, graphite,
zinc oxide.
Filter - Any device or porous substance used for cleaning
liquid or gas by removing suspended matter.
Fire Point - The temperature at which an oil, when
subjected to a source if ignition or flame, will ignite and continue
to burn.
Fire Resistant Fluid - A fluid, difficult to ignite, that
shows little tendency to propagate flame.
Flash Point (C.O.C.) - The temperature to which a combustible
liquid must be heated to give off substantial vapor to form a
momentarily flammable mixture with air when a small flame is
applied under specific conditions.
Fluid Friction - Occurs between the molecules of a
gas or liquid in motion, and is expressed as shear stress. Unlike
solid friction, fluid friction varies with speed and area.
Foam - An agglomeration of gas bubbles separated from
each other by a thin liquid film. If an oil is said to not foam,
the small air bubbles will quickly combine, become larger bubbles,
and then break to vent to the atmosphere. If this action occurs
slowly, the oil is said to foam.
Four Ball Test - Machine used to evaluate a lubricant's
antiwear qualities, frictional characteristics, or load carrying
capabilities. There are four steel 1/2'inch balls. Three of the
balls are held together in a cup filled with lubricant while
the fourth ball is rotated against them.
Four Stroke Engine - An internal combustion engine
which requires two revolutions of the crankshaft to complete
all of its cycles.
Friction - Resistance to motion of one object over
another. Friction depends on the smoothness of the contacting
surfaces, as well as the force with which they are pressed together.
Fuel Dilution - The amount of unburned fuel present
in the lubricant. This test will indicate problems such as fuel
line, injector, carburetor and pump leaks. Fuel dilution is accurate
down to less than 0.5%.
Full Film Lubrication - Complete separation of mated
surfaces. metal contact.
No metal-to-
Full Flow Filtration - A system of filtration in which
the total flow of a circulating fluid system passes through a
filter.
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Gears - Toothed machine parts for transmitting power
from one shaft to another.
Gravity - The mass/volume relationship of lubricants
used in determining volume requirements for specific mass of
products (packaging).
Grease - Lubricant composed of an oil or oils thickened
with a soap, soaps or other thickener to a semi-solid consistency.
Gum - A rubber like, sticky deposit black or dark brown
in color resulting from the oxidation of lubricating oils from
unstable constituents in gasoline which deposit during storage
or use.
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Heat Transfer - Taking heat from one part of a system
and releasing it in another.
Horsepower - A measurement of an engine's power, equal
to 550 foot pounds of torque per second.
Hydraulic Oil - Light oils designed specifically for
use in hydraulic systems, however, lending themselves to other
applications as well.
Hydrocarbons - Compounds containing carbon and hydrogen.
Petroleum consists chiefly of hydrocarbons. Also known as organic
compounds.
Hydrofinishing - A process for treating raw extracted
base stocks with hydrogen to saturate them for improved stability.
Hydrolytic Stability - Ability of additives and certain
synthetic lubricants to resist chemical decomposition (hydrolysis)
in the presence of water.
Hypoid Gear Lubricant - A gear lubricant having extreme
pressure characteristics for use in hypoid type gears (as in
the differential of an automobile).
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Inhibitor - Additive than improves the performance
of a petroleum product by controlling undesirable chemical reactions,
i.e., oxidation inhibitor, rust inhibitor, etc.
Insolubles - Contaminates found in used oils due to dust,
dirt, wear particles or oxidation products.
I.S.O. (International Standards Organization) - Among
other responsibilities, they establish viscosity standards for
industrial oils. Viscosity is measured in centistokes at 40°Celsius.
This method is known as Kinematic Viscosity.
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JAMA - Japanese Automobile Manufacturers Association
Inc.
Journal - Part of shaft or axle that rotates or angularly
oscillates in or against a bearing or about which a bearing rotates
or angularly oscillates.
Keg - Container which would typically hold 16 gallons
of oil or approximately 120 pounds of grease-type product. Also
called a "quarter drum".
Kinematic Viscosity - Measure of a fluid's resistance
to flow under gravity at a specific temperature (usually 40°C
or 100°C).
Low Pour Point - means an oil which will pour at Iow
temperatures.
Lubrication - Control of friction and wear by the introduction
of a friction reducing film between moving surfaces in contact.
May be a fluid, solid, or plastic substance.
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Material Safety Data Sheets (MSDS) - Information which
gives vial information regarding transportation, safe handling
and storage of a lubricant or other product.
Micron - A millionth of a meter, or 0.0000394 inch.
Mineral Oil - Term applied to a wide range of products
with viscosity's within a range of product considered as petroleum
type oil.
Mini Rotary Viscometer - An instrument used to measure
the borderline pumping temperature (BPT) of engine oils from
O°C to -40°C. BPT is the lowest temperature at which
engine oil can be supplied in adequate amounts to the oil pump
inlet.
Multiviscosity/Multi Grade Oil - An oil meeting both cold
temperature viscosity requirements and high temperature viscosity
requirements. In SAE viscosity descriptions, a number with a
"W" behind it has met certain cold temperature requirements,
a number without a "W" behind it has met certain high
temperature requirements.
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Naphthenic - A type of petroleum fluid derived from
naphthenic crude oil, containing a high proportion of closed-ring
methylene groups.
Newtonian Flow - Occurs in a liquid system where the
rate of shear is directly proportional to the shearing force,
as with straight grade oils which do not contain polymeric viscosity
modifier. When rate of shear is not directly proportional to
the shearing force, flow is non-Newtonian, as it is with oils
containing viscosity modifiers.
Nitration - Process where nitrogen oxides attack petroleum
fluids at high temperatures, often resulting in viscosity increase
and deposit formation. only occurs in applications where fuel
is used.
Nitration
N.L.G.I. - National Lubricating Grease Institute, an
industry group that monitors grease and sets penetration standards
for grading greases.
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Octane - Measure of the anti-knock properties of gasoline.
Oil - A greasy liquid of vegetable, animal, mineral
or synthetic origin.
Oiliness - Property of a lubricant that produces Iow
friction under conditions of boundary lubrication, the lower
the friction, the greater the oiliness.
Organic Acid - An organic compound, with acid properties,
obtained from organic substances such as animal, vegetable and
mineral oils, i.e., a fatty acid.
Oxidation - Occurs when oxygen attacks fluids. The
process is accelerated by heat, light, metal catalysts and the
presence of water, acids, or solid contaminants. It leads to
increased viscosity and deposit formation.
Oxidation Inhibitor - Substance added in small quantities
to an oil product to increase its oxidation resistance, thereby
lengthening its service or storage life. Also called an antioxidant.
Oxidation Stability - Resistance of an oil product
to oxidation and, therefore, a measure of its potential service
or storage life.
Oxygenated Fuels - Fuels for internal combustion engines
that contain oxygen combined in the molecule, e.g., alcohols,
ethers and ester. Term also applies to blends of gasoline with
oxygenates, e.g., Gasohol, which contains 10% by volume of anhydrous
ethanol in unleaded gasoline.
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Paraffin - Hydrocarbons belonging to the series starting
with methane (CH4). Paraffins are saturated with respect to hydrogen.
High molecular weight paraffins are solid such as paraffin wax.
PCV (Positive Crankcase Ventilation) Valve - An emissions
control device that allows gases from the crankcase to be reintroduced
into the intake.
Penetration - A test in which a cone is dropped into
a grease to measure the penetration or how hard or soft the grease
is at room temperatures. The cone penetrated farther in a soft
grease and therefore has a higher penetration number. This penetration
relates to an NLGI number. A number 0 grease is called an NLGI
grade and will be "softer" than an NLGI 1 or 2 grade.
pH - Term used to denote the degree of acidity or alkalinity
of aqueous solutions. Values of pH run from 0-14, 7 indicating
neutrality, number less than 7 indicate increasing acidity, and
number greater than 7 indicate increasing alkalinity.
Poise - Unit of viscosity, defined by the shear stress
required to move one layer of fluid along another over a total
thickness of one centimeter at a velocity of one centimeter per
second. This viscosity is independent of fluid density, and directly
related to flow resistance.
Polishing (bore) - Excessive smoothing of the surface
finish of the cylinder bore or cylinder liner in an engine to
a mirror-like appearance, resulting in depreciation of ring sealing
and oil consumption performance.
Polymerization - Chemical combination of similar type
molecules to form larger molecules.
Pour Point - An indicator of the ability of an oil
or distillate fuel to flow at cool operating temperatures. It
is the lowest temperature at which the fluid will flow when cooled
under prescribed conditions.
Pour Point Depressant - Additive used to lower the
pour point or lower temperature fluidity of a petroleum product.
Preignition - Ignition of the fuel/air mixture in a
gasoline engine before the spark plug fires. Often caused by
incandescent fuel or lubricant deposits in the combustion chamber,
it wastes power and may damage the engine.
Propylene Glycol - A non-toxic liquid used as an coolant/antifreeze
in cooling and heating systems.
Pumpability - The Iow temperature, Iow shear stress-shear
rate viscosity characteristics of an oil that permit satisfactory
flow to and from the engine oil pump and subsequent lubrication
of moving components.
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Refining - Series of processes to convert crude oil
and its fractions into finished petroleum product, which may
include thermal cracking, catalytic cracking, polymerization,
alkylation, reforming, hydrocracking, hydrofoaming, hydrogenation,
hydrogen treating, Hydrofining®, solvent extraction, dewaxing,
de-oiling, acid treating, clay filtration, deasphalting, etc..
Rerefining - A process of reclaiming used lubricant
oils and restoring them to a condition similar to that of virgin
stock by filtration, clay adsorption or more elaborate methods.
Ring Sticking - Freezing of a piston ring in its groove
in a piston engine or reciprocating compressor due to heavy deposits
in the piston ring zone.
Rust - Slow oxidation of iron.
Rust Preventative - Compound for coating iron surfaces
with a film that protects against rust. Commonly used to preserve
equipment in storage.
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SAE - Society of Automotive Engineers.
SAE Grade - Numbers applied to automotive lubricants
to indicate their viscosity range.
Saybolt, Saybolt Universal Seconds, SUS or SSU - The
most common viscosity measurement prior to the international
acceptance of centistokes, SUS measures are now obsolete. To
convert measurements from SUS at 100°F to an approximate
value in cSt at 40°C (ISO viscosity grade), divide the SUS
value by 5.
Scuffing - Abnormal engine wear due to localized welding
and fracture. It can be prevented through the use of antiwear,
extreme-pressure and friction modifier additives. See adhesion.
Semi Fluid - Any substance having attributes of both
a liquid and a solid. Similar to semi solid but being more closely
related to a liquid than a solid.
Shear Stability - Ability of a lubricant to withstand
shearing forces without being degraded to lower viscosity or
consistency.
Sludge - A thick, dark residue, normally of mayonnaise
consistency, that accumulates on non-moving engine interior surfaces.
Generally removable by wiping unless baked into a carbonaceous
consistency, its formation is associated with insolubles overloading
the lubricant.
Soap - A thickener in grease.
Solid - Any substance having definite shape which it
does not readily relinquish. More generally, any substance in
which the force required to produce a deformation depends upon
the magnitude of the deformation rather than the rate of deformation.
Stoichiometric - Ratio of fuel to air where the exact
proportions for complete reaction of both, with none left over,
are present.
Stoke (St) - Kinematic measurement of a fluid's resistance
to flow defined by the ratio of the fluid's dynamic viscosity
to density.
Supercharger - A device for increasing the pressure
and hence the mass of air and fuel burned on each firing stroke.
Driven by the crankshaft; therefore, displacement is fixed and
directly related to engine RPM's.
Surface Tension - The contractile surface force of
a liquid by which it tends to assume a spherical form and to
present the least possible surface. It is expressed in dyne/cm
or ergs/cm.
SUS - See Saybolt.
Synthetic Lubricant - Fluid made by chemically reading
materials to produce a lube with a specific chemical composition
which has planned and predictable properties.
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Thermally Stable - Ability to withstand temperatures
without decomposing. Not to be confused with oxidation stability
where oxygen must be present and oxidation rather than decomposition.
Thickener - The metallic soap or other material used
to combine with oil or other lubricating fluid to make grease.
Thixotropy - Decrease in consistency, as a result of
shearing/followed by an increase in hardening after the shearing
stopped.
Torque - The twisting force with which the engine's
crankshaft actually rotates, measured in foot pounds.
Total Acid Number (TAN) - The quantity of base, expressed
in milligrams, that are required to neutralize all acidic constituents
present in one gram of sample.
Total Base Number (TBN) - The quantity of acid, expressed
in terms of the number of milligrams that are required to neutralize
all basic constituents present in one gram sample
Total Solids - The total amount of solids contamination,
both suspended and non-suspended present in the lubricant. This
test is indicative of carburetion problems (too rich or too lean),
if the oil filter has reached the saturation point and is no
longer able to remove contamination from the system, and if the
air intake system is functioning properly and allowing enough
air into the unit for complete burn to take place.
Turbine - A device consisting of blades attached to
a disc or rotor which converts flow into rotary action.
Turbocharger - A device for increasing the pressure
and hence the mass of air and fuel burned on each firing stroke.
A turbine of exhaust gases drives a compressor; therefore, efficiency
is variable and related to exhaust pressure.
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Vapor Lock - Condition wherein the fuel boils in the
fuel system forming bubbles which retard or stop the flow of
fuel to the engine.
Viscosity - Measure of a fluid's resistance to flow.
Viscosity Index (VI) - Relationship of viscosity to
temperature of a fluid. High viscosity index fluids tend to display
less change in viscosity with temperature than Iow viscosity
index fluids.
Viscosity Index Improver (VII) - Additive to "improve
or increase the viscosity index". A VI improver increases
an oil's resistance to thinning as it is heated. It is commonly
used in multi-viscosity or multi-grade oils. Since a VI improver
increase the viscosity as well as the viscosity index, it must
be taken into consideration when formulating oil. (Example: Taking
an oil in the SAE 30 range, adding a VI improver could give an
oil like a SAE 40.
Viscosity Modifier - SEE VII. Additive, usually a high
molecular weight polymer, that reduces the tendency of an oil's
viscosity to change with temperature
Zinc (ZDP) - Commonly used name for zinc dithiophosphate,
and antiwear/oxidation inhibitor chemical.
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