AAMA
The American Automobile Manufacturers
Association (AAMA) is a trade
association that represents car
manufacturers headquartered in the United
States.
After the purchase of Chrysler by German Daimler-Benz
the organization has
been dissolved on December 31, 1998.
absolute viscosity
the ratio of shear stress to shear rate.
It is a fluid’s internal resistance to
flow.
The common unit of absolute viscosity is
the poise (see viscosity).
Absolute
viscosity divided by the fluid’s density equals kinematic
viscosity.
absorber oil
oil used to selectively absorb heavier
hydrocarbon components from a gas
mixture. Also called wash oil or scrubber
oil.
absorption
process by, which one substance draws
into itself another substance;
the assimilation of one material into
another;
in petroleum refining, the use of an
absorptive liquid to selectively
remove components from a process stream.
Examples: a sponge picking up water; an
oil recovering gasoline from wet
natural gas.
ACEA
Association des Constructeurs Europeens
Automobiles
(Association of the European Automobile Manufacturers)
is the new
association of the European automobile
manufacturers, formed in February
1991. ACEA is engaged in a broad range of
activities including safety and
environmental concerns and any
regulations which have a direct impact on
the European automobile industry. ACEA
members are all the European motor
vehicle manufacturers including Ford
Europe, GM Europe, Scania, and Volvo.
At present, only Peugeot is not a member
of ACEA but cooperates with ACEA
in the field of lubricating oils and
fuels.
acid
A member of an important and fundamental
category of chemical substances
characterized by having an available
reactive hydrogen and requiring an
alkali to neutralize them. Acid solutions
usually have a sour, biting, and
tart taste, like vinegar. pH is less than
7.
acid sludge
The residue left after treating petroleum
oil with sulfuric acid for the
removal of impurities. It is a black,
viscous substance containing the
spent acid and impurities.
acid treating
A refining process in which unfinished
petroleum products, such as
gasoline, kerosene, and lubricating oil stocks,
are contacted with
sulfuric acid to improve their color,
odor, and other properties.
acidity
The amount of free acid in any substance.
additive
An agent or chemical substance added to a
product and used for imparting
new, or for improving existing
characteristics of lubricating oils or
greases.
Common petroleum product additives are:
anti-foam agent
anti-icing additive
anti-oxidant
anti-wear additive
corrosion inhibitor
demulsifier
detergent
dispersant
emulsifier
EP additive
fluidizer
oiliness agent
oxidation inhibitor
pour point depressant
rust inhibitor
tackiness agent
viscosity index (V.I.) improver
additive level
The total percentage of all additives in
an oil. (Expressed in % of mass
[weight] or % of volume)
adhesion
The force or forces causing two materials
such as a lubricating grease and
a metal, to stick together.
adsorption
adhesion of the molecules of gases,
liquids, or dissolved substances to a
solid surface, resulting in relatively
high concentration of the molecules
at the place of contact; e.g., the
plating out of an anti-wear-additive on
metal surfaces.
Also, any refining process in which a gas
or a liquid is contacted with a
solid, causing some compounds of the gas
or liquid to adhere to the solid;
e.g., contacting of lube oils with
activated clay to improve color.
See clay filtration
aerosol
a highly dispersed suspension (Colloidal
System) of fine solid or liquid
particles in a gas.
Petroleum solvents are commonly used
either as carriers or as vapor
pressure depressants in packaged aerosol
specialty products. Petroleum
products are also applied in aerosol form
in agricultural oil applications
and oil mist lubrication.
AFV
Alternate Fuel Vehicle
AGMA
American Gear Manufacturers Association
air entrainment
The incorporation of air in the form of
bubbles as a dispersed phase in
the bulk liquid. Air may be entrained in
a liquid through mechanical means
and/or by release of dissolved air due to
a sudden change in environment.
The presence of entrained air is usually
readily apparent from the
appearance of the liquid (i.e., bubbly,
opaque, etc.) while dissolved air
can only be determined by analysts.
aliphatic hydrocarbon
hydrocarbon in which the carbon atoms are
joined in open chains, rather
than rings.
See normal paraffin.
alkali
In chemistry, any substance having basic
properties. The term is applied
to hydroxides of ammonium, lithium,
potassium, and sodium. They are
soluble in water; have the power to
neutralize acids and form salts. They
turn red litmus blue. In a more general
sense, the term is also applied to
the hydroxides of the so-called alkaline
earth metals: barium, calcium,
and strontium.
alkyl
any of a series of monovalent radicals
having the general formula CnH2n+1,
derived from aliphatic hydrocarbons by
the removal of a hydrogen atom; for
example, CH3- (methyl radical, from
methane).
alkylate
product of an alkylation process.
alkylated aromatic
benzene-derived synthetic lubricant base
with good hydrolytic stability
(resistance to chemical reaction with
water) and good compatibility with
mineral oils.
Used in turbines, compressors, jet
engines, and hydraulic power steering.
alkylation
in refining, the chemical reaction of a
low-molecular-weight olefin with
an isoparaffin to form a liquid product,
alkylate, that has a high octane
number and is used to improve the antiknock
properties of gasoline. The
reaction takes place in the presence of a
strong acid catalyst, and at
controlled temperature and pressure.
Alkylation less commonly describes
certain other reactions, such as that of
an olefin with an aromatic
hydrocarbon.
Almen EP lubricant tester
A Journal bearing machine used for
determining the load-carrying capacity
or Extreme Pressure properties (EP) of
gear lubricants.
ambient temperature
Temperature of the area or atmosphere
around a process, (not the operating
temperature of the process itself).
anhydrous
Free of water, especially of
crystallization.
aniline point
The minimum temperature for complete
miscibility of equal volumes of
aniline and the sample under test ASTM
Method D
aniline point will be low in aromatics
and naphthenes and, therefore, high
in paraffins. Aniline point is often
specified for spray oils, cleaning
solvents, and thinners, where effectiveness depends upon aromatic
content.
In conjunction with API gravity, the
aniline point may be used to
calculate the net heat of combustion for
aviation fuels.
anti-foam agent
An additive used to control foam.
two types of additives are used to
reduce foaming in petroleum products:
silicone oil to break up large
surface bubbles
polymers of various kinds that
decrease the amount of small
bubbles entrained in the oils
See foaming
antifreeze solution
A fluid, such as ethylene or propylene
glycol, which is added to or used
to replace the water in the cooling
system of engines in order to prevent
freezing.
anti-friction bearing(s)
A type of bearing using rollers, cones or
balls. They are also known as
rolling element bearings.
anti-icing additive
substance added to gasoline to prevent
ice formation on the throttle plate
of a carburetor. Anti-icing additives are
of two types:
those that lower the freezing point of
water
those that alter the growth of ice
crystals so that they remain small
enough to be carried away in the air
stream.
antiknock
Resistance to detonation or pinging in
spark-ignition engines.
Resistance of a gasoline to detonation in
a combustion chamber.
See antiknock index, octane number.
antiknock compounds
substances which raise the antiknock
quality of a gasoline, as expressed
by octane number. Historically,
tetraethyl lead (lead alkyl) has been the
most common antiknock compound, but its
use is being phased out under
Environmental Protection Agency (EPA)
regulations. Coming into increasing
use as octane boosters are toluene and
oxygenated organic type substances
such as methyl tertiary butyl ether
(MTBE) and tertiary amyl methyl ether
(TAME).
antiknock index
the average of the Research Octane Number
and Motor Octane Number; a
measure of the octane quality of a
gasoline.
According to EPA and FTC regulations the
antiknock index of any gasoline
sold in the
use in motor vehicles.
See octane number.
antioxidant
chemical added to lubricating oils to
resist oxidation.
anti-seize compound
grease-like substance containing
graphite, moly or metallic solids
(Copper, Zinc, Silver or Lead), which is
applied to threaded joints,
particularly those subjected to high
temperatures, to facilitate
separation when required.
anti-wear additive
additive in a lubricant that reduces
friction and excessive wear.
See boundary lubrication.
API
The American Petroleum Institute (API) is
a trade association that
promotes
technology, cooperates with the
government in matters of national concern,
and provides information on the petroleum
industry to the government and
the public.
API Engine Service Classification System
Classifications and designations for
lubricating oils for automotive
engines developed by API in conjunction
with SAE and ASTM. An recently
also with ILSAC.
API Gear Lubricant Service Designation
Classifications and designations for
lubricating oils for automotive
transmissions developed by API in
conjunction with SAE and ASTM.
API gravity
A nonscientific and arbitrary scale
expressing the gravity or density of
liquid petroleum products. The measuring
scale is calibrated in terms of
degrees API. It may be calculated in
terms of the following formula:
apparent viscosity
The ratio of shear stress to rate of
shear of a non-Newtonian fluid such
as lubricating grease, or a multi-grade
oil, calculated from Poiseuille’s
equation and measured in poises. The
apparent viscosity changes with
changing rates of shear and temperature
and must, therefore, be reported
as the value at a given shear rate and temperature
(ASTM Method D 1092).
aromatic
Derived from, or characterized by, the
presence of the benzene ring.
unsaturated hydrocarbon identified by one
or more benzene rings or by
chemical behavior similar to benzene. The
benzene ring is characterized by
three double bonds alternating with
single bonds between carbon atoms
(compare with olefins). Because of these
multiple bonds, aromatics are
usually more reactive and have higher
solvency than paraffins and
naphthenes. Aromatics readily undergo
electrophylic substitution; that is,
they react to add other active molecular
groups, such as nitrates,
sulfonates, etc.
Aromatics are used extensively as
petrochemical building blocks in the
manufacture of pharmaceuticals, dyes,
plastics, and many other chemicals.
ASEAN
Association of South-East Asian Nations
ash content
The percent by weight of residue left
after combustion of an oil or fuel
sample.
(ASTM Method D 482 or D 874 [sulfated
ash]).
Lubricating oil detergent additives
contain metallic derivatives, such as
barium, calcium, and magnesium
sulfonates, that are common sources of ash.
Ash deposits can impair engine efficiency
and power.
See detergent
ASLE
American Society of Lubrication Engineers
This society is still in
existence but is now known as the Society
of Tribologists and Lubrication
Engineers (STLE). The ASLE had published standards
for machine tool
lubricants.
asperities
microscopic projections on metal surfaces
resulting from normal
surface-finishing processes. Interference
between opposing asperities in
sliding or rolling applications is a
source of friction, and can lead to
metal welding and scoring. Ideally, the
lubricating film between two
moving surfaces should be thicker than
the combined height of the opposing
asperities.
See boundary lubrication, EP additive
asphalt
Black to dark-brown solid or semisolid
cemetitious material which
gradually liquefies when heated and in
which the predominating
constituents are bitumen’s. These occur
in the solid or semisolid form in
nature; are obtained by refining
petroleum; or are combinations with one
another or with petroleum or derivatives
thereof.
asphaltic
Essentially composed of, or similar to,
asphalt; frequently used to
describe lubricating oils derived from
crude oils which contain asphalt.
ASTM
The American Society for Testing and
Materials (ASTM) is a professional
society that is responsible for the
publication of test methods and the
development of test evaluation techniques.
ATC
Technical Committee of the Petroleum
Additive Manufacturers
(ATF) Automatic Transmission Fluid
fluid for automatic transmissions in
motor vehicles. Automatic
transmission fluids must have a suitable
coefficient of friction, good
low-temperature viscosity, and anti-wear
properties. Other necessary
properties are: high oxidation stability,
anti-corrosion, anti-foaming,
and compatibility with synthetic rubber
seals.
See corrosion, foaming.
ATIEL
Association Technique de L’lndustrie
Europeene des Lubrifiants
auto-ignition
In realtion to Fuels & Combustion
in Internal Combustion Engines it is
the spontaneous ignition, and the
resulting very rapid reaction, of a
portion or all of the fuel-air mixture
in an engine. The flame speed is
many times greater than that which
follows normal spark ignition. The
noise associated with it is called
knock.
In realtion to Lubricants it is the
Temperature at which the lubricant
will self ignite when exposed to air
and continue to burn.
B
bactericide
additive included in the formulations of
water-mixed cutting fluids or
coolants,
to inhibit the growth of bacteria
promoted by the presence of water,
thus preventing the unpleasant odors that
can result from bacterial
action.
barrel
Standard unit of liquid measurement in
the petroleum industry.
Used to measure quantities of crude oil,
gasoline and fuel oils.
Equivalent of 42 U.S. Gallons.
base
any of a broad class of compounds,
including alkalis, that react with
acids to form salts, plus water. Also
known as hydroxides. Hydroxides
ionize in solution to form hydroxyl ions
(OH-); the higher the
concentration of these ions, the stronger
the base. Bases are used
extensively in petroleum refining in
caustic washing of process streams to
remove acidic impurities, and are
components in certain additives that
neutralize weak acids formed during
oxidation.
Base Oil
A base oil is a base stock or blend of
base stocks used in an API-licensed
engine oil.
Base oil interchangeability
refers to an API approved system, that
reduces testing costs by permitting
the interchangeable use of certain base
oils, without requiring a full
engine test program for each of the base
oils.
Base Stock
A base stock is a mineral hydrocarbon or
synthetic lubricant component
that is produced by a single manufacturer
(independent of crude source or
manufacturing location), that meets the
same manufacturer’s specification,
and that is identified by a unique
formula, product identification number,
or both.
batch
Any quantity of material handled or
considered as a "unit" in processing.
I.e., any sample taken from the same
"batch" will have the same properties
and/or qualities.
bearing
basic machine component designed to
reduce friction between moving parts
and to support moving loads.
There are two main types of bearings:
rolling contact bearings (also called
anti-friction bearings) commonly
ball or roller
sliding (plain) bearings, either plain
journal (a metal jacket fully or
partially enclosing a rotating inner
shaft) or pad-type bearings, for
linear motion.
Rolling-contact bearings are more
effective in reducing friction. With few
exceptions, bearings require lubrication
to reduce wear and extend bearing
life.
Bench Test
A bench test is a laboratory test that
measures various specific
performance parameters of an engine oil.
Specialized test equipment is
used for bench testing.
bentonite
The mineral montmorillonite, a
magnesium-aluminum silicate. Used as a
treating agent, also, as a component of drilling
mud, and in greases.
benzene
Colorless liquid hydrocarbon, C6H6, with
one ring of carbon atoms. Made
from coal tar and by catalytic reforming
of naphthenes, it is used in the
manufacture of phenol, styrene, nylon,
detergents, aniline, phthalic
anhydride, biphenyl, nitrobenzene,
chlorbenzene; as a solvent; and as a
component of high-octane gasoline.
benzene insoluble
That portion of the normal pentane
insoluble in used lubricating oils
which is not soluble in benzene, and
which may include the insoluble
contaminants from external sources, some
matter produced by oxidation and
thermal decomposition of the oil, the oil
additives, or the fuel.
(It is tested by ASTM Method D 893).
blending
The process of mixing lubricants or
components for the purpose of
obtaining the desired physical and/or
chemical properties (see
compounding).
bloom
Fluorescence; the color of an oil by
reflected light which could differ
from its color by transmitted light.
blow-by
in an internal combustion engine, seepage
of fuel and gases past the
piston rings and cylinder wall into the
crankcase, resulting in crankcase
oil dilution and deposit formation.
See positive crankcase ventilation, .
boiling point
The temperature at which a substance
boils, or is converted into vapor by
bubbles forming within the liquid; it
varies with pressure.
bottoms
The liquid which collects in the bottom
of a vessel (tower bottoms, tank
bottoms), either during a fractionating
process or while in storage.
boundary lubrication
The state of lubrication when conditions
exist that do not permit the
formation of a lubricant film capable of
completely separating the moving
parts. As a result the asperities of the
moving parts come in contact and
a high wear rate results.
Brookfield viscosity
apparent viscosity of an oil, as
determined under test method ASTM D 2983.
Since the apparent viscosity of a
non-Newtonian fluid holds only for the
shear rate (as well as temperature) at
which it is determined, the
Brookfield viscometer provides a known rate
of shear by means of a spindle
of specified configuration that rotates
at a known constant speed in the
fluid. The torque imposed by fluid
friction can be converted to absolute
viscosity units (centipoises) by a
multiplication factor. See viscosity,
shear stress. The viscosities of certain
petroleum waxes and wax-polymer
blends in the molten state can also be
determined by the Brookfield test
method ASTM D 2669.
bright stock
Refined, high viscosity base oils usually
made from residual stocks by
suitable treatment, such as a combination
of solvent extraction, propane
asphating or catalytic dewaxing.
British Thermal Unit (BTU)
The quantity of heat required to raise,
by
pound of water at its maximum density (
BS&W
The material which collects at the bottom
of storage tanks, usually
composed of oil, water and foreign
matter. Also called Bottoms or Bottom
Settling & Watter.
BTC
British Technical Council
butane
A gas that is composed of either or both
of two isomeric, flammable,
gaseous hydrocarbons, C4H10, of the
paraffin series: n-butane or
isobutane.
Also called, along with propane, liquefied
petroleum gas (LPG).
C
CAFE
Corporate Average Fuel Economy
Minimum Fuel Economy for Cars and Light
Trucks established by U.S.
Congress.
It is currently 27.5 MPG for Cars and
20.7 MPG for Light Trucks
calorie
The amount of heat required to raise
the temperature of
1ºC, at or near the temperature of
maximum density. This unit is called
a "small calorie", or
"gram calorie".
The amount of heat required to raise
the temperature of
This unit is called a "large
calorie" or "kilogram-calorie".
capillary viscometer
A viscometer in which the oil flows
through a capillary tube.
CARB
California Air Resources Board
carbon monoxide (CO)
colorless, odorless, poisonous gas,
formed by the incomplete combustion of
any carbonaceous material (e.g.,
gasoline, wood, coal). CO is the most
widely distributed and most commonly
occurring air pollutant, with motor
vehicles being the primary source of
man-made emissions, although emission
controls are reducing the automobile’s
contribution. It is estimated that
more than 90% of atmospheric CO comes
from natural sources, such as
decaying organic matter.
See catalytic converter,
carburetor
device used with an internal combustion
engine to atomize and mix fuel
with air in the proper proportion for
efficient combustion at all engine
speeds. It controls the engine’s power
output by throttling, or metering,
the air-fuel mixture admitted to the
cylinders.
The automobile carburetor is a complex mechanism
designed to compensate
for many variables over a wide range of
speeds and loads.
Intake air is drawn through the venturi,
a constricted throat in the air
passage that causes a pressure reduction
in the air stream, which draws
fuel from the carburetor bowl through
either the main jet or the idle jet.
The fuel is atomized by the high-velocity
air, and the resulting air-fuel
mixture is piped through the intake
manifold to the individual cylinders,
where it is burned.
A throttle plate between the venturi and
the cylinders controls power and
speed by controlling the volume of
air-fuel mixture reaching the
cylinders. In most carburetors, closing
of this (venturi) throttle valve
shuts down the main jet and activates the
idle jet, which provides the
fuel-rich mixture that idling requires.
An accelerator pump in the
carburetor provides momentary fuel
enrichment when the accelerator pedal
is depressed rapidly, to compensate for
the sudden influx of air.
During cold starting, a choke (or
butterfly valve) restricts airflow to
the carburetor, thus enriching the
mixture for faster starting. The choke
on most automotive engine carburetors is
operated automatically by a
thermostatic spring, which opens the
choke as the engine warms up.
See fuel injection,
Carrier Oil
Oil (Petroleum), usually solvent neutral
(SN) or process oil, used to
"carry" or dissolve and/or disperse
additives, which would otherwise be
too viscous or even solid, and therefore
not easily mixed with the Base
Stock Oil.
catalyst
substance that causes or speeds up a
chemical reaction without itself
undergoing an associated change;
catalysts are important in a number of
refining processes.
catalytic converter
an emissions control device, incorporated
into an automobile’s exhaust
system, containing catalysts — such as
platinum, palladium, or rhodium —
that reduce the levels of hydrocarbons
(HC), carbon monoxide (CO) and
nitrogen oxides (NOx) emitted to the air.
In the catalytic converter, HC
and CO are oxidized to form carbon
dioxide (CO2), and NOx are reduced to
nitrogen and oxygen. Three-way catalytic
converters that control all three
substances require associated electronic
controls for precise regulation
of oxygen levels in the exhaust gas.
Catalytic converters are also
effective in removing PNA (polynuclear
aromatic) hydrocarbons. Cars
equipped with catalytic converters
require unleaded gasoline, since the
lead in tetraethyl lead, an antiknock
compound, is a catalyst "poison."
See hydrocarbon emissions
catalytic cracking
in refining, the breaking down at
elevated temperatures of large,
high-boiling hydrocarbon molecules into
smaller molecules in the presence
of a catalyst. The principal application
of catalytic cracking is the
production of high-octane gasoline, to supplement the gasoline produced
by
distillation and other processes.
Catalytic cracking also produces heating
oil components and hydrocarbon
feedstocks, such as propylene and butylene,
for polymerization, alkylation, and
petrochemical operations.
cavitation
formation of an air or vapor pocket (or
bubble) due to lowering of
pressure in a liquid, often as a result
of a solid body, such as a
propeller or piston, moving through the
liquid; also, the pitting or
wearing away of a solid surface as a
result of the collapse of a vapor
bubble. Cavitation can occur in a
hydraulic system as a result of low
fluid levels that draw air into the
system, producing tiny bubbles that
expand explosively at the pump outlet,
causing metal erosion and eventual
pump destruction. Cavitation can also
result when reduced pressure in
lubricating grease dispensing systems
forms a void, or cavity, which
impedes suction and prevents the flow of
greases.
CCMC
Comite des Constructeurs d'Automobile du
Marche Commun
(European Common Market Automobile Manufacturers
Association)
European vehicles. This organization was
dissolved at the end of 1990.
ACEA, the new association of the European
automobile manufacturers, formed
in February 1991, has decided to retain
the CCMC oil sequences and their
original designation for a transitional
period.
CEC
Coordinating European Council
cellulose
the chief substance composing the cell
walls or fibers of all plant
tissue, a polymeric carbohydrate with the
general formula (C6H10O5)x: it
is used in the manufacture of paper,
textiles, filters, etc.
centistoke (cSt)
The worldwide unit of kinematic
viscosity.
channeling
The phenomenon observed among gear
lubricants and greases when they
thicken due to cold weather or other causes,
to such an extent that a
groove is formed through which the part
to be lubricated moves without
actually coming in full contact with
the lubricant.
A term used in percolation filtration;
may be defined as: a
preponderance of flow through certain
portions of the clay bed.
CID
Commercial Item Description used in many
cases in lieu of military
specification (MIL).
clay filtration
refining process using fuller’s earth
(activated clay) or bauxite to
adsorb minute solids from lubricating
oil, as well as remove traces of
water, acids, and polar compounds.
See adsorption
cloud point
The temperature at which paraffin wax or
other solid substances begin to
crystallize or separate from the
solution, imparting a cloudy appearance
to the oil when chilled (ASTM Method D
97).
CMA
Chemical Manufacturers Association is the
trade association responsible
for the development and administration of
the Petroleum Additives Panel
Product Approval Code of Practice (CMA
Code).
Coking
(a) The undesirable accumulation of
carbon (coke) deposits in the internal
combustion engine or in a refinery plant.
(b) The process of distilling a petroleum
product to dryness.
colloid
a solid, liquid, or gaseous substance
made up of very small, insoluble,
nondiffusible particles (as single
large molecules or masses of smaller
molecules) that remain in suspension in
a surrounding solid, liquid, or
gaseous medium of different matter
a state of matter consisting of such a
substance dispersed in a
surrounding medium All living matter
contains colloidal material, and a
colloid has only a negligible effect on
the freezing point, boiling
point, or vapor pressure of the
surrounding medium
[< Greek kolla, glue + -oid; coined by
T. Graham (1805-69), Scottish
chemist]
Colloidal particles are 5 to 5000 angstroms
in size. In a gas or liquid
medium, they do not settle and are not
easily filtered.
Colloids are usually ionically stabilized
by some form of surface charge
on the particles to reduce the tendency
to agglomerate.
A lubricating grease is a colloidal
system, in which metallic soaps or
other thickening agents are dispersed in,
and give structure to, the
liquid lubricant.
SynLube™ Lube-4-Life™ Lubricants are
colloidal systems, in which solid
graphite, moly and PTFE colloids are
dispersed in synthetic liquid
lubricants.
color
A factor in the identification, rather
than in the quality rating of a
petroleum products and lubricants, except
where staining or appearance are
considerations.
combustion
rapid oxidation of a fuel (burning).
The products of an ideal combustion
process are water (H2O) and carbon
dioxide (CO2); if combustion is
incomplete, some carbon is not fully
oxidized, yielding carbon monoxide (CO).
A stoichiometric combustible mixture
contains the exact quantities of air
(oxygen) and fuel required for complete
combustion. For gasoline, this
air-fuel ratio is about 15:1 by weight or
about 9,500:1 by volume.
If the fuel concentration is too rich or
too lean relative to the oxygen
in the mixture, combustion cannot take
place.
See internal combustion engine.
combustion chamber
in an internal combustion engine, the
volume, bounded by the top of the
piston and the inner surface of the
cylinder head, in which the air-fuel
charge ignites and burns. Valves and
spark plugs are fitted into the
combustion chamber.
complex grease
A lubricating grease thickened by a
complex soap consisting of a normal
soap and a complexing agent.
compounding
The addition of fatty oils and similar
materials to lubricants to impart
special properties. Lubricating oils to
which such materials have been
added are known as compounded oils.
compounded oil
mixture of a petroleum oil with animal or
vegetable fat or oil. Compounded
oils have a strong affinity for metal
surfaces; they are particularly
suitable for wet-steam conditions and for
applications where lubricity and
extra load-carrying ability are needed.
They are not generally recommended
where long-term oxidation stability is
required.
copper strip corrosion
The gradual eating away of copper
surfaces as the result of oxidation or
other chemical action.
It is caused by acids or other corrosive
agents.
corrosion
The gradual eating away of metallic surfaces
as the result of oxidation or
other chemical action.
It is caused by acids or other corrosive
agents or by electro-chemical
reaction of the metal with its
environment.
Corrosion Inhibitor
substance which protects a metal against
corrosion by substances which
originate from products of combustion, or
from deterioration of the
lubricant.
cracking
petroleum refining process in which
large-molecule liquid hydrocarbons are
converted to small-molecule,
lower-boiling liquids or gases; the liquids
leave the reaction vessel as unfinished
gasoline, kerosene, and gas oils.
At the same time, certain unstable, more
reactive molecules combine into
larger molecules to form tar or coke .
The cracking reaction may be
carried out under heat and pressure alone
(thermal cracking), or in the
presence of a catalyst (catalytic
cracking).
Crankcase oil
Lubricant used in the crankcase of the
internal combustion engine.
Also referred to as:Motor Oil
Engine Oil
PCMO (Passenger Car Motor
Oil)
DHD (Diesel Heavy Duty)
DEO (Diesel Engine Oil)
crude oil
complex, naturally occurring fluid
mixture of petroleum hydrocarbons,
yellow to black in color, and also
containing small amounts of oxygen,
nitrogen and sulfur derivatives and other
impurities. Crude oil was formed
by the action of bacteria, heat, and
pressure on ancient plant and animal
remains, and is usually found in layers
of porous rock such as limestone
or sandstone capped by an impervious
layer of shale or clay that traps the
oil (reservoir). Crude oil varies in
appearance and hydrocarbon
composition depending on the locality
where it occurs, some crudes being
predominantly naphthenic, some
paraffinic, and others asphaltic. Crude is
refined to yield petroleum products.
See asphalt, distillation, sour crude,
sweet crude, naphthene, paraffin.
CUNA
Commissione Tecnica de Unificazione nel
l'Autoveicolo
D
demulsibility
ability of an oil to separate from water,
as determined by test method
ASTM D 1401 or D 2711. Demulsibility is an
important consideration in
lubricant maintenance in many circulating
lubrication systems.
demulsifier
additive that promotes oil-water
separation in lubricants that are exposed
to water or steam.
See demulsibility.
density
The mass of a unit of volume of a
substance as compared to Water which has
a density of one.
DEO
Diesel Engine Oil
detergency
The ability of an oil to keep working
surfaces of equipment clean (i.e.
free from contaminants) by holding
oil-insoluble material in suspension
thus preventing deposition where it would
be harmful.
detergent
important additive component of engine oils
and some industrial
lubricants, such as paper machine oils
and hydraulic fluids; helps control
deposits by preventing contaminants of
combustion from directly contacting
metal surfaces and, in some cases, by
neutralizing acids. A detergent is
usually a metallic (commonly barium,
calcium, or magnesium) compound, such
as a sulfonate, phosphonate,
thiophosphonate, phenate, or salicylate.
Because of its metallic composition, a
detergent leaves a slight ash when
the
oil is burned. A detergent is normally used in conjunction with a
dispersant.
detergent oil
Is a lubricating oil possessing special
sludge-dispersing properties
usually conferred on the oil by the
incorporation of special additives.
Detergent oils hold formed sludge
particles in suspension and thus promote
cleanliness especially in
internal-combustion engines. However detergent
oils do not contain
"detergents" such as those used for cleaning of
laundry or dishes. Also detergent oils do not
clean already "dirty"
engines, but rather keep in suspension
the sludge that petroleum oil forms
so that the engine remains cleaner for
longer period. The formed sludge
particles are either filtered out by Oil
Filters or drained out when oil
is changed.
DHD
Diesel Heavy Duty Engine Oil
dielectric strength
A measure of the of insulating properties
of electrical insulating oils
for use in electrical cables,
transformers, circuit breakers, and similar
apparatus (Tested by ASTM Method D 877).
diester oil
A synthetic Iubricating fluid made from
esters: also called ester oil or
an organic ester, formed by reacting a dicarboxylic
acid and an alcohol;
properties include a high viscosity index
(V.I.) and low volatility. With
the addition of specific additives, it
may be used as a lubricant in
compressors, hydraulic systems, and
internal combustion engines.
DIN
Deutsche Industrie Norm (German
Industrial Standards).
diolefin
highly reactive straight-chain
hydrocarbon with two double bonds between
adjacent carbon atoms.
See olefin
dispersant
A dispersing agent, which holds a very
finely divided substance in a
dispersed state in the carrier fluid.
Such as sludge or a wear particles
in a motor oil.
In engine oil dispersant is additive that
helps prevent sludge, varnish,
and other engine deposits by keeping
particles suspended in a colloidal
state (see colloid) within the bulk oil.
Dispersants are normally used in
conjunction with detergents.
A dispersant can be distinguished from a
detergent in that the former may
be non-metallic and thus does not leave
an ash when the oil is burned;
hence the term ashless dispersant.
distillate
Wide range of and any product produced by
distillation.
distillation
The process of condensing into liquid the
vapours distilled from any
liquid such as water, petroleum or
alcohol.
In the petroleum oil industry it is the
primary refining step, in which
crude oil is separated into fractions, or
components, in a distillation
tower, or pipe still. Heat, usually
applied at the bottom of the tower,
causes the oil vapors to rise through
progressively cooler levels of the
tower, where they condense onto plates
and are drawn off in order of their
respective condensation temperatures, or
boiling points — the
lighter-weight, lower-boiling-point
fractions, exiting higher in the
tower. The primary fractions, from low to
high boiling point, are:
hydrocarbon gases (e.g., ethane,
propane); naphtha (e.g., gasoline);
kerosene, diesel fuel (heating oil); and
heavy gas oil for cracking. Heavy
materials remaining at the bottom are
called the bottoms, or residuum, and
include such components as heavy fuel oil
(fuel oil) and asphaltic
substances (see asphalt). Those fractions
taken in liquid form from any
level other than the very top or bottom
are called sidestream products; a
product, such as propane, removed in
vapor form from the top of the
distillation tower is called overhead
product. Distillation may take place
in two stages: first, the lighter
fractions — gases, naphtha, and kerosene
— are recovered at essentially
atmospheric pressure; next, the remaining
crude is distilled at reduced pressure in a
vacuum tower, causing the
heavy lube fractions to distill at much
lower temperatures than possible
at atmospheric pressure, thus permitting
more lube oil to be distilled
without the molecular cracking that can
occur at excessively high
temperatures.
See hydrocracking.
DKA
Deutsche Koordinierungsausschuss
dropping point
In general, the dropping point is the
temperature at which the grease
passes from a semisolid to a liquid
state. This change in state is typical
of greases containing conventional soap
thickeners. Greases containing
thickeners other than conventional soaps
may, without change in state,
separate Oil
dry
lubricant
Solid material left between two moving
surfaces to prevent metal-to-metal
contact, thus reducing friction and wear.
Such materials are especially
useful in the region of boundary
lubrication, and for lubrication under
special conditions of extremely high or low temperature where usual
lubricants are inadequate. They may be
applied in the form of a paste or
solid stick, or by spraying, dipping, or
brushing in an air-drying carrier
which evaporates leaving a dry film. Or
can be present in a "sol", a
colloidal suspension in Water, Alcohol or
Oil.
Some examples of dry lubricants are:
graphite
molybdenum disulfide (moly)
boron nitride
lastics such as tetrafluorethylene
resins (PTFE or Teflon).
E
EC & ECII
Energy Conserving (1.5% Fuel Conserving)
and Energy Conserving Level II
(2.7% Fuel Conserving). It is the ability
of lubricant to conserve fuel in
gasoline automotive type engines when
compared to ASTM HR-2 20W-30
reference motor oil.
elastohydrodynamic lubrication
Lubrication model modified to take into
consideration the elastic
properties of the bearing material and
the viscosity increase of the
lubricant under concentrated load.
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 adsorbed by
activated carbon contained in a canister
installed on the vehicle. Blow-by
HC emissions from the crankcase are
controlled by positive crankcase
ventilation (PCV). 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 (EGR) and increasingly
sophisticated technology for improving
combustion efficiency, including
electronic emission controls.
emulsibility
The ability of a non-water soluble fluid
(such as oil) to form an emulsion
with water.
emulsifier
A substance used to promote or aid the emulsification
of two liquids and
to enhance the stability of the emulsion.
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).
Emulsion
A mechanical mixture of two insoluble
liquids such as oil and water.
Energy Conserving Oil
engine oil categories developed by SAE,
ASTM, and API, based on an oil’s
fuel-saving performance in passenger
cars, vans, and light trucks.
Originally "Energy Conserving"
rating was based on the average fuel
economy gain of a five vehicle test, this however proved to be too
costly
and difficult to repeat the test results.
Later engine-stand test was used for
"Energy Conserving" oil which must
have produced a fuel economy improvement
of 1.5% or greater over a
reference oil (ASTM HR-2) in a standard
ASTM test procedure. An "Energy
Conserving II" oil must have
produced a fuel economy improvement of at
least 2.7%.
With ILSAC GF-2 and API SJ the
"Energy Conserving II" rating was dropped
and only one "Energy
Conserving" rating was used, but with different
values based on motor oils SAE Viscosity
rating.
(Note: the fuel economy gain of SynLube™
SAE 5W-50 Motor Oil in ASTM test
is 5% when compared to HR-2 test oil)
Since all current motor oil ratings such
as API SK, ILSAC GF-3 incorporate
"Energy Conserving" performance
into their specifications, and therefore
most motor oils on the market today are
"Energy Conserving". The rating is
not as important as it once was.
In actual vehicle operation, the fuel
economy obtained by these lubricants
differs, depending on vehicle type,
operating conditions, and driving
habits. Therefore the fuel saving ability
of any Motor Oil is mostly a
theoretical value.
In real life day-to-day operation, a fuel
saving of less than 2% is not
possible to verify, since tank-to-tank
fuel economy in normal driving can
vary by up to 20%.
See fuel-economy oil.
engine deposits
hard or persistent accumulations of
sludge, varnish, and carbonaceous
residues due to blow-by of unburned and
partially burned (partially
oxidized) fuel, and/or from partial
breakdown of the crankcase lubricant.
Water from condensation of combustion
products, carbon, residues from fuel
or lubricating oil additives, dust, and
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. 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
An engine oil is a lubricating agent that
can be classified according to
one or a combination of the viscosity grades
identified in Table 1 of the
most recent edition of SAE Standard J300.
Engine OiIs are also called
Motor Oils. Engine oils include diesel
engine oils and passenger car motor
oils (PCMOs).
Engine test
Also called engine sequence test or
sequence test, it refers to a test of
an oil’s performance using a full-scale
engine operating under laboratory
conditions.
Engler degree
A measure of viscosity. The ratio of the
time of flow of 200 ml of the
liquid tested, through the viscometer
devised by Engler, to the time
required for the flow of the same volume
of water gives the number of
degrees Engler.
EOLCS
Engine Oil Licensing and Certification
System (EOLCS) refers to an
administrative process and legally
enforceable system by which API
authorizes marketers of engine oil to
display an API Mark or Marks on oils
that meet specified industry standards,
as prescribed in a formal
licensing agreement.
EPA
Environmental Protection Agency
agency of the federal executive branch,
established in 1970 to abate and
control pollution through monitoring,
regulation, and enforcement, and to
coordinate and support environmental
research.
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.
EP agent
An Extreme Pressure additive introduced
into a lubricant to improve the
load-carrying or anti-weld qualities.
EP lubricant
Any of the lubricating oils or greases
which contain an Extreme Pressure
additive specifically introduced to
prevent metal-to-metal contact in the
operation of highly loaded gears. In some
cases, this is accomplished by
the additive reacting with the metal to
form a protective film.
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.
F
fat
An animal or vegetable oil which will
combine with an alkali to saponify
and
form a soap.
fiber grease
A grease with a distinctly fibrous
structure, which is noticeable when
portions of the grease are pulled apart.
filler (lubricants)
Any substance, such as talc, mica, or
various powders, which may be added
to a grease to make it heavier in weight
or consistency, but which serves
no useful function in making the grease a
better lubricant. (Editor’s
note: Starch filler may also be added to
certain lubricating oil or other
lubricants).
film strength
The property of an oil which enables it
to maintain an unbroken film on
lubrIcated surfaces under operatIng
conditions, where other otherwise
there would be scuffing or scoring of the
surfaces.
Fire Point
The lowest temperature at which an oil or
other product vaporizes
sufficiently rapidly to form above its
surface an air-vapor mixture which
when subjected to a source of ignition or
a flame, will ignite and
continue to burn.
Typically for most Petroleum products the
Fire Point is about
the Flash Point.
Flash Point
The lowest temperature at which vapors
arising from the oil will ignite
momentarily, when subjected to a flame.
(i.e., will flash or "poof").
The vapors will ignite and then go out.
floc point
The temperature at which wax or solids
separate in an oil.
fluidizer
high boiling-point, thermally stable
organic liquid used as an additive in
gasoline to reduce deposits on the
undersides of intake valves; also
called solvent oil.
See engine deposits
foam
An agglomeration of gas bubbles separated
from each other by a thin liquid
film which is observed as a persistent
phenomenon on the surface of a
liquid.
foaming
occurrence of frothy mixture of air and a
petroleum product (e.g.,
lubricant, fuel oil) that can reduce the
effectiveness of the product, and
cause sluggish hydraulic operation, air
binding of oil pumps, and overflow
of tanks or sumps. Foaming can result
from excessive agitation, improper
fluid levels, air leaks, cavitation, or
contamination with water or other
foreign materials. Foaming can be
inhibited with an anti-foam agent. The
foaming characteristics of a lubricating
oil can be determined by blowing
air through a sample at a specified
temperature and measuring the volume
of foam, as described in test method ASTM
D 892.
Foam inhibitor
A substance introduced in a very small
proportion to a lubricant or a
coolant to prevent the formation of foam
due to aeration of the liquid,
and to accelerate the dissipation of any
foam that may form.
Four-Ball Tester
This name is frequently used to describe
either of two similar laboratory
machines, the Four-Ball Wear Tester and
the Four-Ball EP Tester. These
machines are used to evaluate a
lubricant’s anti-wear qualities,
frictional characteristics or load
carrying capabilities. It derives its
name from the four 1/2 inch steel balls
used as test specimens. Three of
the balls are held together in a cup
filled with lubricant while the
fourth ball is rotated against them.
friction
a rubbing, esp. of one object against
another.
Mechanics: The resistance to motion of
two moving objects or surfaces
that touch.
Tribology: The resisting force encouraged at the common boundary between
two bodies when, under the action of an
external force, one body moves
or tends to move relative to the other.
[<French < Latin frictio < pp.
of fricare, to rub]
Friction is the resistance to the motion
of one surface over another. The
amount of friction is dependent on the
smoothness of the contacting
surfaces, as well as the force with which
they are pressed together.
Friction between unlubricated solid
bodies is independent of speed and
area.
The coefficient of friction is obtained
by dividing the force required to
move one body over a horizontal surface
at constant speed by the weight of
the body.
Coefficients of rolling friction (e.g.,
the motion of a tire or ball
bearing) are much less than coefficients
of sliding friction (back and
forth motion over two flat surfaces).
Sliding friction is thus more wasteful of
energy and can cause more wear.
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.
In general, lubrication is the
substitution of low fluid friction in place
of high solid-to-solid friction.
See asperities, tribology.
fretting
form of wear resulting from
small-amplitude oscillations or vibrations
that cause the removal of very finely
divided particles from rubbing
surfaces (e.g., the vibrations imposed on
the wheel bearings of an
automobile when transported by rail car,
or on the fifth wheel on tractor
trailers). With ferrous metals the wear
particles oxidize to a reddish,
abrasive iron oxide, which has the
appearance of rust or corrosion, and is
therefore sometimes called fretting
corrosion; other terms applied to this
phenomenon are false Brinelling
(localized fretting involving the rolling
elements of a bearing) and friction
oxidation. Fretting can be controlled
with lubricants containing molybdenum
disulfide.
fretting corrosion
A special case of fretting in which one
or more of the surfaces, or the
wear particles therefrom, react with their
environment. Mechanical wear
initiates fretting, then chemical action
or "corrosion" results from the
exposure of virgin metal surface to the
to the air.
fuel-economy oil
engine oil specially formulated to
increase fuel efficiency. A
fuel-economy oil works by reducing the
friction between moving engine
parts that wastefully consumes fuel
energy.
There are only three known and proven
means of accomplishing this goal:
by reducing the viscosity of the oil to
decrease fluid friction
by using friction-reducing chemical
additives in the oil to prevent
metal-to-metal contact, or rubbing
friction, between surface asperities
by introducing solid colloidal
particles between surface asperities
See Energy Conserving/ Energy
Conserving II.
fuel injection
method of introducing fuel into the
combustion process as a finely divided
spray under pressure through a small
nozzle. Fuel injection is essential
to the compression-ignition process of
the diesel cycle.
In the majority of newer-model
gasoline-powered cars fuel injection has
replaced carburetion, largely due to EPA
exhaust emission standards: fuel
injection improves combustion efficiency,
resulting in lower emissions.
The location and design of fuel injectors
is somewhat different between
diesel and gasoline engines.
In the diesel engine fuel is injected directly
into the cylinder or the
pre-combustion chamber. Since the
injector nozzle intrudes into the
cylinder it must be durable and
relatively insensitive to deposit
formation in the injector passages.
In most gasoline engines, the fuel is
injected into the intake manifold
leading to the cylinder, either by a
single throttle-body injector or by
multiple port injectors (one for each
cylinder). Gasoline engine port
injectors are highly deposit sensitive, due
to their extremely narrow
passage clearances of only
two-thousandths of an inch and their proximity
to high combustion temperatures. This
deposit sensitivity required
gasoline suppliers to develop a new
generation of gasoline additives that
could keep these passages deposit-free.
Diesel engine manufacturers have
begun to express interest in diesel fuel
additives that can reduce
deposits, thereby increasing combustion
efficiency and improving emissions
control.
Fuel injection offers a number of
advantages over carburetion, including:
more precise metering of fuel in
the cylinders for improved
combustion
more positive delivery of fuel to
the cylinder (hence, easier
starting and faster acceleration)
higher power output because of
improved volumetric efficiency
reduced exhaust emissions.
See carburetor, engine deposits, internal combustion engine.
full-fluid-film lubrication
presence of a continuous lubricating film
sufficient to completely
separate two surfaces, as distinct from
boundary lubrication.
Full-fluid-film lubrication is normally
hydrodynamic lubrication, whereby
the oil adheres to the moving part and is
drawn into the area between the
sliding surfaces, where it forms a
pressure, or hydrodynamic, wedge. See
ZN/P curve.
A less common form of
full-fluid-lubrication is hydrostatic lubrication,
wherein the oil is supplied to the
bearing area under sufficient external
pressure to separate the sliding
surfaces.
FZG test
A German gear test for evaluating EP
properties.
G
gasoline (automotive)
blend of light hydrocarbon fractions of
relatively high antiknock value.
Automotive, or motor, gasoline may
consist of the following components:
straight-run naphthas, obtained by the
primary distillation of crude oil;
natural gasoline, which is
"stripped", or condensed, out of natural gas;
cracked naphthas; reformed naphthas; and
alkylate. (See alkylation,
catalytic cracking, reforming).
A high-quality gasoline has the following
properties:
proper volatility to ensure easy
starting and rapid warm-up
clean-burning characteristics to
minimize harmful combustion chamber
deposits
additives to prevent rust, oxidation,
and deposits in carburetors,
intake valves and fuel injectors
sufficiently high octane number to
prevent engine knock.
gasoline, aviation (avgas)
high-quality gasoline manufactured under
stringent controls to meet the
rigorous performance and safety
requirements of piston-type aircraft
engines.
Volatility of aviation gasoline is
closely controlled since, in most
aircraft engines, excessive volatility
can lead to vapor lock. Aviation
gasolines generally have lower vapor
pressure and a narrower distillation
range than automotive gasolines (see distillation test). Aviation
gasolines are formulated to resist
chemical degradation and to prevent
fuel system corrosion. There are two
basic grades of aviation gasolines
(based on their antiknock value): 80 (80
lean/87 rich) and 100 (100
lean/130 rich). Aviation gasoline has
different properties than turbo
fuel, which fuels gas-turbine-powered
aircraft.
gear
machine part which transmits motion and
force from one rotary shaft to
another by means of successively engaging
projections, called teeth. The
smaller gear of a pair is called the
pinion; the larger, the gear. When
the pinion is on the driving shaft, the
gear set acts as a speed reducer;
when the gear drives, the set acts as a
speed multiplier. The basic gear
type is the spur gear, or straight-tooth
gear, with teeth cut parallel to
the gear axis. Spur gears transmit power
in applications utilizing
parallel shafts. In this type of gear, the teeth mesh along their full
length, creating a sudden shift in load
from one tooth to the next, with
consequent noise and vibration. This
problem is overcome by the helical
gear, which has teeth cut at an angle to
the center of rotation, so that
the load is transferred progressively
along the length of the tooth from
one edge of the gear to the other. When
the shafts are not parallel, the
most common gear type used is the bevel
gear, with teeth cut on a sloping
gear face, rather than parallel to the
shaft. The spiral bevel gear has
teeth cut at an angle to the plane of
rotation, which, like the helical
gear, reduces vibration and noise. A
hypoid gear resembles a spiral bevel
gear, except that the pinion is offset so
that its axis does not intersect
the gear axis; it is widely used in
automobiles between the engine
driveshaft and the rear axle. Offset of
the axes of hypoid gears
introduces additional sliding between the
teeth, which, when combined with
high loads, requires a high-quality EP
oil. A worm gear consists of a
spirally grooved screw moving against a
toothed wheel; in this type of
gear, where the load is transmitted
across sliding, rather than rolling,
surfaces, compounded oils or EP oils are
usually necessary to maintain
effective lubrication.
gear oil (automotive)
long-life oil of relatively high viscosity
for the lubrication of rear
axles and some manual transmissions. Most
final drives and many
accessories in agricultural and
construction equipment also require gear
oils. Straight (non-additive) mineral
gear oils are suitable for most
spiral-bevel rear axles (see gear) and
for some manual transmissions. Use
of such oils is declining, however, in
favor of EP (extreme-pressure) gear
oils (see EP oil) suitable both for
hypoid gears (see gear) and for all
straight mineral oil applications. An EP
gear oil is also appropriate for
off-highway and other automotive
applications for which the lubricant must
meet the requirements of Military
Specification MIL-L-2105D.
gravity (See API gravity)
graphite
a soft form of elemental carbon, gray to
black, in color. It occurs
naturally or is synthesized from coal or
other carbon sources. It is used
in the manufacture of paints, lead
pencils, crucibles, and electrodes, and
is
also widely used as a lubricant, either alone as a dry lubricant or
added to conventional lubricants; both
oils and greases.
grease
A lubricant composed of a lubricating
fluid, thickened with soap or other
material to a solid or semisolid
consistency.
A lubricating grease is a colloidal
system, in which metallic soaps or
other thickening agents are dispersed in,
and give structure to, the
liquid lubricant.
H
heat transfer fluid
Oil or other liquid medium used for the
transfer of heat.
heavy-duty oil (HD)
an oil suitable for use in commercial
diesel engine service. Also referred
to as HD.
See API Service Categories.
Herschel Demulsibility Number
A number whIch IndIcates the abilIty of
an oIl to separate from water
under condtttons spectfted by the
Herschel Demulstbility Test.
humidity cabinet test
A test used to evaluate the
rust-preventing properties of metal
preservatives under conditions of high
humIdIty (ASTM Method D 1748).
hydraulic fluid
fluid serving as the power transmission
medium in a hydraulic system. The
most commonly used fluids are petroleum
oils, synthetic lubricants,
oil-water emulsions, and water-glycol
mixtures. The principal requirements
of a premium hydraulic fluid are proper
viscosity, high viscosity index,
anti-wear protection (if needed), good
oxidation stability, adequate pour
point, good demulsibility, rust
inhibition (see rust inhibitor),
resistance to foaming, and compatibility
with seal materials. Anti-wear
oils are frequently used in compact,
high-pressure, and high-capacity
pumps that require extra lubrication
protection. Certain synthetic
lubricants and water-containing fluids
are used where fire resistance is
needed. Synthetic lubricants also are
used in extreme-temperature
conditions.
hydrocarbon
A compound containing only hydrogen and
carbon. The simplest hydrocarbons
are gases at ordinary temperatures; but
with increasing molecular weight,
they change to the liquid form and,
finally, to the solid state. They form
the principal constituents of petroleum.
hydrocarbon (HC) emissions
substances considered to be atmospheric
pollutants because the more
reactive hydrocarbons (e.g., aromatics)
undergo a photochemical reaction
with nitrogen oxides (NOx) to form
oxidants, components of smog that can
cause eye irritation and respiratory
problems. Motor vehicles account for
about one-third of man-made hydrocarbon
emissions, although automotive
emission controls are reducing this
amount. The greatest portion of total
atmospheric hydrocarbons is from natural
sources, such as pine trees.
Up to 20% of Heavy Hydrocarbon exhaust
emissions are generated by Motor
Oils.
See catalytic converter,
hydrocracking
refining process in which middle and
heavy distillate fractions are
cracked (broken into smaller molecules)
in the presence of hydrogen at
high pressure and moderate temperature to
produce high-octane gasoline,
turbo fuel components, and middle distillates
with good flow
characteristics and cetane ratings. The
process is a combination of
hydrogenation and cracking.
See distillation.
hydrodynamic (fluid film) lubrication
An oil film which provides a pressure equal
to the load. This pressure
enables the moving parts to float on a
layer of lubricant.
hydrogenation
The chemical addition ot hydrogen to a
material. In non-destructive
hydrogenation, hydrogen is added to a
molecule only if, and where,
unsaturation with respect to hydrogen
exists.
In destructive hydrogenation, the
operation is carried out under
conditions which result in rupture of
some of the hydrocarbon chains
(cracking); hydrogen is added where the
chain breaks have occurred.
hypoid gears
Gears in which the pinion axis intersects
the plane of the ring gear at a
point below the ring-gear axle and above
the outer edge of the ring gear,
or above the the ring-gear axle and below
the outer edge of the ring gear.
Hypoid gear lubricant
A gear lubricant, having extreme pressure
characteristics suitable for use
with hypoid gears as found, for example,
in the differentials of motor
vehicles.
I
ILMA
The Independent Lubricant Manufacturers
Association (lLMA) is a trade
association of businesses engaged in
compounding, blending, formulating,
packaging, marketing, and distributing
lubricants.
ILSAC
The International Lubricant
Standardization and Approval Committee (ILSAC)
is a joint committee of AAMA and JAMA
members that assists in the
development of new minimum oil
performance standards.
inhibitor
A substance in a petroleum product which prevents
or retards undesirable
chemical changes from taking place in the
product, or in the condition of
the equipment in which the product is
used. Commonly used inhibitors are
used to prevent or retard oxidation or
corrosion.
internal combustion engine
heat engine driven directly by the
expansion of combustion gases, rather
than by an externally produced medium,
such as steam. Basic versions of
the internal combustion engine are:
gasoline engine and gas engine (spark
ignition), diesel engine (compression
ignition), and gas turbine
(continuous combustion). Diesel
compression-ignition engines are more
fuel-efficient than gasoline engines
because compression ratios are
higher, and because the absence of air
throttling improves volumetric
efficiency. Gasoline, gas (natural gas,
propane), and diesel engines
operate either on a four-stroke cycle
(Otto cycle) or a two-stroke cycle.
Most gasoline engines are of the four-stroke
type, with operation as
follows:
intake - piston moves down the
cylinder, drawing in a fuel-air mixture
through the intake valve
compression - all valves closed, piston
moves up, compressing the
fuel-air mixture, and spark ignites
mixture near top of stroke
power - rapid expansion of hot
combustion gases drives piston down, all
valves remain closed
exhaust - exhaust valve opens and
piston returns, forcing out spent
gases
The diesel four-stroke cycle differs in
that only air is admitted on the
intake stroke, fuel is injected at the
top of the compression stroke, and
the fuel-air mixture is ignited by the
heat of compression rather than by
an
electric spark.
The four-stroke-cycle engine has certain
advantages over a two-stroke,
including higher piston speeds, wider
variation in speed and load, cooler
pistons, no fuel lost through the
exhaust, and lower fuel consumption.
The two-stroke cycle eliminates the
intake and exhaust strokes of the
four-stroke cycle. As the piston ascends,
it compresses the charge in the
cylinder, while simultaneously drawing a
new fuel-air charge into the
crankcase, which is air-tight. (In the
diesel two-stroke cycle, only air
is drawn in; the fuel is injected at the
top of the compression stroke.)
After ignition, the piston descends on
the power stroke, simultaneously
compressing the fresh charge in the
crankcase. Toward the end of the power
stroke, intake ports in the piston skirt
admit a new fuel-air charge that
sweeps exhaust products from the cylinder
through exhaust ports; this
means of flushing out exhaust gases is
called "scavenging". Because the
crankcase is needed to contain the intake
charge, it cannot double as an
oil reservoir. Therefore, lubrication is
generally supplied by oil that is
pre-mixed with the fuel. An important
advantage of the two-stroke-cycle
engine is that it offers twice as many
power strokes per cycle and, thus,
greater output for the same displacement
and speed. Because two-stroke
engines are light in relation to their
output, they are frequently used
where small engines are desirable, as in chain
saws, outboard motors, and
lawn mowers.
Many commercial, industrial, and railroad
diesel engines are also of the
two-stroke type.
Gas turbines differ from conventional
internal combustion engines in that
a continuous stream of hot gases is
directed at the blades of a rotor. A
compressor section supplies air to a
combustion chamber into which fuel is
sprayed, maintaining continuous
combustion. The resulting hot gases expand
through the turbine unit, turning the
rotor and driveshaft.
See fuel injection,
lP
Institute of Petroleum.
ISO
International Standards Organization
This organization which is worldwide in
scope sets standards and
classifications for lubricants. An
example is the ISO viscosity grade
system.
ISO viscosity classification system
international system, approved by the
International Standards Organization
(ISO),
for classifying industrial lubricants
according to viscosity.
Each ISO viscosity grade number
designation corresponds to the mid-point
of a viscosity range expressed in
centistokes (cSt) at
For example:
lubricant with an ISO grade of 32 has a
viscosity within the range of 28.8
— 35.2 cSt, the mid-point of which is 32.
(see Table below)
ISO viscosity grade number Table:
viscosity range expressed in centistokes
(cSt) at
ISO #Mid-PointMinimumMaximum
22.21.982.42
33.22.883.52
54.64.145.06
76.86.127.48
10109.011.0
151513.516.5
222219.824.2
323228.835.2
464641.450.6
686861.274.8
10010090110
1,5015E+11
2,2022E+11
3,2032E+11
4,6046E+11
6,80681E+11
1,0001E+14
1,50015E+15
isomer
molecule having the same molecular formula as another
molecule, but having
a different structure and, therefore,
different properties. As the carbon
atoms in a molecule increase, the number
of possible combinations, or
isomers, increases sharply.
For example, octane, an 8-carbon-atom
molecule, has 18 isomers; decane, a
10-carbon-atom molecule, has 75 isomers.
isooctane
an isomer of octane (C8H18) having very
good antiknock properties. With a
designated octane number of 100,
isooctane is used as a standard for
determining the octane number of gasolines.
isoparaffin
branched isomer of a straight-chain
paraffin molecule.
isothermal
pertaining to the conduct of a process or
operation of equipment under
conditions of constant temperature. Heat
is neither generated nor absorbed
by the process.
J
JAMA
The Japan Automobile Manufacturers
Association (JAMA) is a trade
association that represents automobile
manufacturers headquartered in
Japan.
JASO
Japanese Automobile Standards
Organization (JASO) is comprised of
automobile and truck manufacturers, oil
and oil additive companies, and
government authorities.
JIS
Japanese Industrial Standards
K
kinematic viscosity
absolute viscosity of a fluid divided by
its density at the same
temperature of measurement. It is the
measure of a fluid’s resistance to
flow under gravity, as determined by test
method ASTM D 445. To determine
kinematic viscosity, a fixed volume of
the test fluid is allowed to flow
through a calibrated capillary tube
(viscometer) that is held at a closely
controlled temperature. The kinematic
viscosity, in centistokes (cSt), is
the product of the measured flow time in
seconds and the calibration
constant of the viscometer.
See viscosity.
L
lubricant
any substance reducing friction by
providing a smooth film as a covering
over parts that move against each
other; lubricating
a substance for reducing friction in
this way, as oil or grease
[Latin lubricans, prp.: see lubricate]
lubricate, lubricated, lubricating
to make slippery or smooth
to apply a lubricant to
to serve as a lubricant
lubrication, lubricative
[< Latin lubricatus, pp. of lubricare,
to make smooth or slippery <
lubricus, smooth, slippery ]
lubricity, lubricities
slipperiness; smoothness; esp.,
effectiveness as a lubricant as
indicated by this quality
trickiness; shiftiness
lubricious, or lubricous
[French lubricité < Latin lubricitas]
ability of an oil or grease to lubricate;
also, called film strength.
Lubricity can be enhanced by additive
treatment.
lyophilic
having a strong affinity for, and
stabilized by, the liquid dispersing
medium: said of a colloidal material.
Also lyophile
[lyo- < Gr lyein, to loose + -phil +
-ic]
lyophobic
having little affinity for the liquid
dispersing medium: said of a
colloidal material
[lyo- (see lyophilic) + -phob(e) + -ic]
M
MVMA
On December 16, 1992, the Motor Vehicle
Manufacturers Association of the
United States (MVMA) changed its name to
the American Automobile
Manufacturers Association (AAMA).
Marketer
refers to the marketing organization
responsible for the integrity of a
brand name and the representation of the branded
product in the
marketplace.
methane
a light, odorless, flammable gas (CH4);
the chief constituent of natural
gas.
micron, -microns or -micra
a unit of linear measure equal to one
millionth of a meter, or one
thousandth of a millimeter
[Modern Latin < Greek mikron, neut. of
mikros, small, minute]
Mineral oil
Oil derived from mineral sources, notably
petroleum.
mineral spirits
naphthas of mixed hydrocarbon composition
and intermediate volatility,
within the boiling range of
flash point greater than
in the manufacture of cleaning products,
paints, lacquers, inks, and
rubber. Also used uncompounded for
cleaning metal and fabrics.
molybdenum disulfide (moly)
a black, lustrous powder (MoS2) that
serves as a dry-film lubricant in
certain high-temperature and high-vacuum
applications. It is also used in
the form of pastes to prevent scoring
when assembling press-fit parts, and
as an additive to impart residual
lubrication properties to oils and
greases.
Molybdenum disulfide is often called moly
or molysulfide.
See fretting
Monograde
'Monograde' (single grade) is a term used
to describe an oil when its
viscosity falls within the limits
specified for a single SAE number.(SAE
Standard J300)
Multigrade
'Multigrade' is a term used to describe
an oil for which the viscosity/
temperature characteristics are such that
its low temperature and high
temperature viscosities fall within the
limits of two different SAE
numbers. (SAE Standard J300)
N
naphtha
generic, loosely defined term covering a
range of light petroleum
distillates (see distillation). Included
in the naphtha classification
are: gasoline blending stocks, mineral
spirits, and a broad selection of
petroleum solvents. In refining, the term
light crude naphtha (LCN)
usually refers to the first liquid
distillation fraction, boiling range
32° to
second distillation fraction, boiling
range 163° to
naphthene
One of a group of cyclic hydrocarbons,
also termed cycloparaffins or
cycloalkanes.
The general formula for naphthenes is
CnH2n
Naphthenic lubricating oils have low pour
points, owing to their very low
wax content, and good solvency
properties.
See saturated hydrocarbon.
Newtonian fluid
fluid, such as a straight mineral oil,
whose viscosity does not change
with rate of flow.
See shear stress
nitrogen oxides (NOx)
nitric oxide (NO), with minor amounts of
nitrogen dioxide (NO2). NOx is
formed whenever fuel is burned at high
temperatures in air, from nitrogen
in the air as well as in the fuel. Motor
vehicles and stationary
combustion sources (furnaces and boilers)
are the primary man-made
sources, although automotive emission
controls are reducing the
automobile’s contribution. Natural
emissions of NOx arise from bacterial
action in the soil. NOx can react with
hydrocarbons to produce smog.
non-Newtonian fluid
fluid, such as a grease or a
polymer-containing oil (e.g., multi-grade
oil), in which shear stress is not
proportional to shear rate.
See Brookfield viscosity
NLGI
National Lubricating Grease Institute
NLGI Number
One of a series of numbers classifying
the consistency range of
lubricating greases.
The NLGI Numbers are based on the ASTM cone
penetration number.
The grades are in order of increasing
consistency (hardness)
NLGI Grease Classifications
The following table shows the worked
penetration values for the various
NLGI grades of grease:
NLGI NumberASTM
Worked Penetration*
000445-475
00400-430
0355-385
1310-340
2265-295
3220-250
4175-205
5130-160
685-115
* ASTM
Worked Penetration in millimeters at standard test temperature of
normal paraffin
hydrocarbon consisting of unbranched
molecules in which any carbon atom is
attached to no more than two other carbon
atoms; also called straight
chain paraffin and linear paraffin.
See isoparaffin, paraffin.
O
octane number
expression of the antiknock properties of
a gasoline, relative to that of
a standard reference fuel. There are two distinct
types of octane number
measured in the laboratory: Research
Octane Number (RON) and Motor Octane
Number (MON), determined in accordance
with ASTM D 2699 and D 2700,
respectively. Both the RON and MON tests
are conducted in the same
laboratory engine, but RON is determined
under less severe conditions, and
is therefore numerically greater than MON
for the same fuel. The average
of the two numbers — (RON + MON)/2 — is
commonly used as the indicator of
a gasoline’s road antiknock performance.
The gasoline being tested is run
in a special single-cylinder engine,
whose compression ratio can be varied
(the higher the compression ratio, the
higher the octane requirement). The
knock intensity of the test fuel, as
measured by a knockmeter, is compared
with the knock intensities of blends of
isooctane (assigned a knock rating
of 100) and heptane (with a knock rating
of zero), measured under the same
conditions as the test fuel. The
percentage, by volume, of the isooctane
in the blend that matches the
characteristics of the test fuel is
designated as the octane number of the
fuel. For example, if the matching
blend contained 90% isooctane, the octane
number of the test fuel would be
method, Road Octane Number, which is
conducted in a specially equipped
test car by individuals trained to hear
trace levels of engine knock.
See antiknock compounds,
OEM
Original Equipment Manufacturer
oiliness agent
polar compound used to increase the
lubricity of a lubricating oil and aid
in preventing wear and scoring under conditions
of boundary lubrication.
olefin
any of a series of unsaturated,
relatively unstable hydrocarbons
characterized by the presence of a double
bond between two carbon atoms in
its structure, which is commonly
straight-chain or branched. The double
bond is chemically active and provides a
focal point for the addition of
other reactive elements, such as oxygen.
Due to their ease of oxidation,
olefins are undesirable in petroleum
solvents and lube oils. Examples of
olefins are: ethylene and propylene.
See unsaturated hydrocarbon.
oxidation
the chemical combination of a substance
with oxygen. All petroleum
products are subject to oxidation, with
resultant degradation of their
composition and performance. The process
is accelerated by heat, light,
metal catalysts (e.g., copper, iron), and
the presence of water, acids, or
solid contaminants. The first reaction
products of oxidation are organic
peroxides. Continued oxidation catalyzed
by peroxides, forms alcohols,
aldehydes, ketones, and organic acids,
which can be further oxidized to
form high-molecular-weight, oil-insoluble
polymers; these settle out as
sludges, varnishes, and gums that can
impair equipment operation. The
organic acids formed from oxidation are
corrosive to metals. Oxidation
resistance of a product can be improved
by careful selection of basestocks
(paraffins have greater oxidation
resistance than naphthenes), special
refining methods, and addition of
oxidation inhibitors. Also, oxidation
can be minimized by good maintenance of
oil and equipment to prevent
contamination and excessive heat.
See engine deposits, oxidation stability.
oxidation inhibitor
substance added in small quantities to a
petroleum product to increase its
oxidation resistance, thereby lengthening
its service or storage life;
also called anti-oxidant.
An oxidation inhibitor may work in one of
three ways:
by combining with and modifying
peroxides (initial oxidation products)
to render them harmless
by decomposing the peroxides
by rendering an oxidation catalyst
(metal or metal ions) inert.
oxidation stability
resistance of a petroleum product to
oxidation; hence, a measure of its
potential service or storage life. There
are a number of ASTM tests to
determine the oxidation stability of a
lubricant or fuel, all of which are
intended to simulate service conditions
on an accelerated basis. In
general, the test sample is exposed to
oxygen or air at an elevated
temperature, and sometimes to water or
catalysts (usually iron or copper).
Depending on the test, results are
expressed in terms of the time required
to produce a specified effect (such as a
pressure drop), the amount of
sludge or gum produced, or the amount of
oxygen consumed during a
specified period.
P
paraffin
hydrocarbon identified by saturated
straight (normal) or branched (iso)
carbon chains; also called an alkane. The
generalized paraffinic molecule
can by symbolized by the formula CnH2n+2.
Paraffins are relatively
non-reactive and have excellent oxidation
stability.
In contrast to naphthenic (see naphthene)
oils, paraffinic lube oils have
relatively high wax content and pour
point, and generally have a high
viscosity index (V.I.).
Paraffinic solvents are generally lower
in solvency than naphthenic or
aromatic solvents.
See normal paraffin, isoparaffin,
saturated hydrocarbon.
particulates
pollutants (e.g., smoke particles,
metallic ash); in sufficient
concentrations, particulates can be a
respiratory irritant. Primary
sources of man-made particulate emissions
are industrial process losses
(e.g., from cement plants) and stationary
combustion sources. Motor
vehicles contribute a relatively minor
amount of particulates however
Diesel Engines generate much more
perticulates in comparison to Gasoline
fueled engines.
PCMO
Passenger Car Motor Oils (PCMOs) refer to
engine oils for passenger cars,
light-duty trucks, and similar vehicles
(see also engine oils).
penetration
Consistency of a lubricating grease,
expressed as the distance in
millimeters that a standard needle or
cone penetrates vertically into a
sample of the material under known
conditions of loading, time and
temperature.
petrochemical
any chemical derived from crude oil,
crude products, or natural gas.
A petrochemical is basically a compound
of carbon and hydrogen, but may
incorporate many other elements.
Petrochemicals are used in the
manufacture of numerous products such as
synthetic rubber, synthetic
fibers (such as nylon and polyester),
plastics, fertilizers, paints,
detergents, and pesticides.
petroleum
From Latin Petra (Rock) and Oleum (Oil)
therefore meaning "Rock Oil " the
term is applied to crude oil and commonly
used to describe products made
from "Crude Oil".
PNA (polynuclear aromatic)
any of numerous complex hydrocarbon
compounds consisting of three or more
benzene rings in a compact molecular
arrangement.
Some types of PNA’s are known to be
carcinogenic (cancer causing). PNA’s
are formed in fossil fuel combustion and
other heat processes, such as
catalytic cracking. They can also form
when foods or other organic
substances are charred. PNA’s occur
naturally in many foods, including
leafy vegetables, grain cereals, fruits,
and meats.
polar compound
a chemical compound whose molecules
exhibit electrically positive
characteristics at one extremity and
negative characteristics at the
other. Polar compounds are used as
additives in many petroleum products.
Polarity gives certain molecules a strong
affinity for solid surfaces; as
lubricant additives (oiliness agents),
such molecules plate out to form a
tenacious, friction-reducing film. Some
polar molecules are oil-soluble at
one end and water-soluble at the other
end; in lubricants, they act as
emulsifiers, helping to form stable
oil-water emulsions. Such lubricants
are said to have good metal-wetting
properties. Polar compounds with a
strong attraction for solid contaminants
act as detergents in engine oils
by keeping contaminants finely dispersed.
polymer
product of polymerization (very large
molecule).
substance formed by the linkage
(polymerization) of two or more simple,
unsaturated molecules (see unsaturated
hydrocarbon), called monomers, to
form a single heavier molecule having the
same elements in the same
proportions as the original monomers;
i.e. each monomer retains its
structural identity.
Polymer may be liquid or solid; solid
polymers may consist of millions of
repeated linked units.
Polymer made from two or more dissimilar
monomers is called a copolymer.
Copolymer composed of three different
types of monomers is a terpolymer.
Natural rubber and synthetic rubbers are
examples of polymers.
Polymers are commonly used as viscosity
index improvers in multi-grade
oils.
polymerisation
The combination, usually under controlled
conditions of temperature and
pressure in the presence of a catalyst,
of two or more unsaturated organic
molecules to form a more complex
molecule. The products obtained are known
as polymers.
Typical polymers range from light liquids
to rubber like materials.
in petroleum refining, polymerization
refers to the combination of light,
gaseous hydrocarbons, usually olefins,
into high-molecular-weight
hydrocarbons that are used in
manufacturing motor gasoline and aviation
fuel.
The product formed by combining two
identical olefin molecules is called a
dimer, and by three such molecules, a
trimer. See polymer.
polyol ester
Synthetic lubricant base, formed by
reacting fatty acids with a polyol
(such as a glycol) derived from petroleum.
Properties include good
oxidation stability at high temperatures
and low volatility. Used in
formulating lubricants for turbines,
compressors, jet engines, and
automotive engines.
polyolefin
polymer derived by polymerization of
relatively simple olefins.
Polyethylene and polyisoprene are
important polyolefins.
positive crankcase ventilation (PCV)
system for removing blow-by gases from
the crankcase and returning them,
through the carburetor intake manifold,
to the combustion chamber, where
the recirculated hydrocarbons are burned,
thus reducing hydrocarbon
emissions to the atmosphere. A PCV valve,
operated by engine vacuum,
controls the flow of gases from the
crankcase. PCV systems have been
standard equipment in all U.S. cars since
1963, replacing the simpler
vent, or breather, that allowed crankcase
vapors to be emitted to the
atmosphere.
See emissions (automotive)
pour point
The lowest temperature at which oil will
pour or flow when it is chilled
without disturbance under definite
conditions (ASTM Method D 97). It gives
an indication of the lowest operating temperature
for which particular oil
is suitable.
pour point depressant
A lubricating oil additive which lowers
the pour point of an oil by
reducing the tendency of the wax,
suspended in the oil, to form crystals
or a solid mass in the oil, thus
preventing flow.
Also called pour depressor or pour point
depressor.
pour stability
The ability of a pour depressed oil to
maintain its original ASTM pour
point when subjected to long term storage
at low temperature aproximating
winter conditions.
process oil
Oil not used for lubrication, but as a
component of another material, or
as a carrier of other products, such as
additives.
process stream
general term applied to a partially
finished petroleum product moving from
one refining stage to another; less
commonly applied to a finished
petroleum product.
See CAS Registry Numbers
propane
gaseous paraffinic hydrocarbon (C3H8)
present in natural gas and crude
oil; also termed, along with butane,
liquefied petroleum gas (LPG).
pumpability (lubricating grease)
The ability of a lubricating grease to
flow under pressure through the
line, nozzle and fitting of a grease
dispensing system.
R
radical
atom or group of atoms with one or more
unpaired electrons. A group of
atoms functioning as a radical acts as a
single atom, remaining intact
during a chemical reaction.
rapeseed oil (blown rapeseed oil)
fatty oil used for compounding petroleum
oil.
See compounded oil
Redwood viscosity
method for determining the viscosity of
petroleum products; it is widely
used in Europe, but has limited use in
the U.S. The method is similar to
Saybolt Universal viscosity; viscosity
values are reported as "Redwood
seconds."
R&O
Rust & Oxidation inhibited
A term applied to highly refined
industrial lubricating oils formulated
for long service in circulating
lubrication systems, compressors,
hydraulic systems, bearing housing, gear
boxes, etc.
The finest R&O oils are often
referred to as turbine oils.
refining
series of processes for converting crude oil
and its fractions to finished
petroleum products. Following
distillation, a petroleum fraction may
undergo one or more additional steps to
purify or modify it.
These refining steps include:
thermal cracking
catalytic cracking
polymerization
alkylation
reforming
hydrocracking
hydroforming
hydrogenation
hydrogen treating
Hydrofining
solvent extraction
dewaxing
de-oiling
acid treating
clay filtration
deasphalting
Refined lube oils may be blended with
other lube stocks, and additives may
be incorporated, to impart special
properties; refined naphthas may be
blended with alkyla