This presentation contains detailed classification of Lubricants on the basis of raw material, usages and viscosity( Monograde oils and Multigrade oils). This presentation will be more helpful to students and researchers by understanding lubricants in details.

1. Engr. Tarique Ahmed Memon
Lecturer @ Department of Mechanical Engineering
Quaid-e-Awam University of Engineering, Science &
Technology (QUEST) Campus Larkano, Sindh, Pakistan.

2. Classification of Lubricants
1. Classification by raw material
2. Classification by use
3. Classification by viscosity
Tarique Ahmed Memon

3. Classification by raw material
Lubricants are developed using base oils produced from crude oil refining by adding additives
according to mixing ratio for each use or developed by compounding chemicals.
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4. Solid Lubricants
• Any material used as a thin film or a powder on a surface to
provide protection from damage during relative movement and
to reduce friction and wear.
• Graphite and molybdenum disulfide particles are common Solid
lubricants.
• Boron nitride, tungsten disulfide and polytetrafluorethylene
(PTFE) are other solid lubricants.
• Solid lubricants are mainly used as additives to oils and greases.
• Solid lubricants are also used in form of dry powder or as
constituents of coatings.
• The bonding of these lubricants onto the surface of various
machine components, such as cylinder liners and piston skirts in
large stationary natural gas engines.
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5. v
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Piston skirt

6. MINERAL OIL
• Mineral oils are derived from the refining of crude
petroleum.
• During the process, natural contaminants and unwanted
hydrocarbons are removed.
• They offer the advantage of low cost.
• Mineral based oils flow through the engine circuit more
slowly.
• This results in increased fuel consumption and impacted
vehicle performance.
• Mineral oils also need to be changed more frequently
than synthetic oils.
• A drop of conventional oil under a microscope shows
millions of molecules all with different shapes, sizes and
structures.
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Synthetic Oil VS Mineral oil

8. Synthetic oils
• Synthetic engine oils are a product of complex chemical
transformations that are performed either directly on crude
petroleum extracted by drilling, or using preselected
molecules.
• Synthetic oil is a lubricant made up of artificially made
chemical compounds;
• these compounds are made by breaking down and then
rebuilding petroleum molecules.
• Under a microscope, a drop of synthetic oil shows millions
of molecules all nearly the same size and structure.
• The difference with mineral oils resides in the
transformation process: synthetic oil undergoes more
sophisticated modifications.
• They contain fewer impurities than mineral oils;
• They are chemically modified.
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10. Advantages of Synthetic oils
Synthetic oils offer many advantages:
Excellent flow at low temperatures
Stable viscosity, even at high temperatures.
Less frequent oil changes
Less deposit formation
Less wear on parts
Optimize fuel consumption
Protect engines and increase
their lifespans.
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13. Classification by Use
• Lubricants are largely used for automobiles,
heavy industries, industries, and vessels.
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14. Classification by viscosity
• Society of Automotive Engineers (SAE) is an
international standard established for the
viscosity of engine oil by the SAE.
• The SAE classifies oil viscosity with a number.
• Viscosity is liquid’s resistance to flow.
• The thicker the oil, the higher the viscosity.
• The thinner the oil, the lower the viscosity.
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15. VISCOSITY GRADES OF AN ENGINE OIL
• The Society of Automotive Engineers (SAE) has developed a system
for classifying oils according to their viscosity grade at low and high
temperatures.
• Monograde Oils
• Multigrade Oils
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16. Monograde Oils
• The grades SAE-XW are only suitable for use in Winter.
• Thin oils good for winter use/cold starting.
• The ‘summer time’ grades SAE-X are more suited for warmer (or
summer time) temperatures or for use in an already hot engine.
SAE XW
(SAE 5W, 10W, 15W and 20W)
SAE X
(SAE 20, 30, 40 and 50)
Winter Season (Cold)
Summer Season (Hot)
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17. Multigrade Oils
• A Multigrade oil meets the requirements of multiple grades.
• — one “W” grade and one single grade, e.g., 5W-30 or 15W-40,
etc.
• This grading system defines the viscosity performance of the oil at
both the low-temperature range and the high-temperature range.
• Produced by blending a low-viscosity base oil with VI improver
additives.
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18. • The SAE viscosity grade is written as
SAE XW Y
Low-Temperature
Viscosity
High-Temperature
Viscosity
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19. SAE 10W-30 Multigrade Oil behaves;
 Cold: like an SAE 10W monograde oil and
 Hot: like SAE 30 monograde oil
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20. Advantages of Multigrade over Monograde Oils
• All the engine oils drops back in crankcase when an engine is at
rest.
• When the vehicle starts again, the oil needs a certain time (a
few microseconds) to reach and lubricate the different parts of
the engine.
• Since a multigrade oil is more fluid at low temperatures, it will
reach all the engine components faster than a monograde oil,
thereby reducing wear at start-up.
• Using multigrade oils can result in fuel savings of 1.5% to 3%
compared to monograde oils.
• A multigrade oil offers better engine protection at low and high
temperature as it maintains optimum viscosity across the
whole engine operating temperature range.
• Engine’s capacity to start, at low temperatures.
• The smaller the number, the easier it is for the engine to start
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22. THE END
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