2. Meaning of lubrication
• Friction - is created when there is
relative motion between two surfaces
• Resistance to motion is defined as
friction
• Lubrication is use of a material
between surfaces to reduce friction
• Any material used is called a lubricant
3. Methods of lubrication cont..
• Two main methods
• Hydrodynamic lubrication
• Boundary lubrication
• Boundary lubrication
• Occurs when Hydrodynamic lubrication
fails.By adsorption or chemical reaction
• Boundary lubrication (h<Ra)
16. Typical lubricants - Application
• Heat Transfer Oils
• Heat Treatment Oils
• Quenching Oils
• Tempering Oils
• Refrigeration Oils
• Rubber Process Oils
• Ink process Oils
17. Lubricant - Components
• Base Oils
• Mineral by-products of crude oil refining
process.
• Base oils are polymerized or
synthesized further and called synthetic
• Additives
• Natural
• Synthetic
18. What Is Engine Grade Oil
American Petroleum Institute (API)
Society of Automotive Engineers (SAE)
19. A Brief History of Motor Oil
1846 Crude oil refining process
discovered
Single Grade oil
Multi Grade oil
Synthetic oil first sold commercially
in 1970
21. Diagnosis
D97, D5950, D5985 Pour Point
D445 Kinematic Viscosity @25؛ and 40؛ C
D2622, D4294, D3120 Sulfur
D92, D93 Flash Point
D1500 Color
D2887 BP Distribution
D5293 Viscosity by Cold Crank Simulator
D5762 Nitrogen by Boat Inlet
D5800 Evaporation Loss
D1298, D4502 Density
D1401 Demulsibility (Water Separation)
D6417 Volatility
D6304 Water
D6045 Color Determination Test
22. How Do Combustion Engines Work?
A General Combustion Engines
take the Linear motion of a
piston and convert it into
Rotation. You can see the
piston moving side to side,
connected to the piston is
the rod, which is then
connected to the Crank,
which delivers your rotation
to whatever you need it for.
You get the piston to move
by combusting fuel and air
creating a high pressure
forcing the piston down on
the “power stroke”. An
engine speed is rated in RPM
(Revolutions per Minute).
Crank Rod Piston Combustion
Chamber
23. Why do engines need oil
Lubrication of moving
parts
Engines move anywhere from 2000RPM-6000RPM
in Street vehicles and up to 19,000RPM + in
Race Engine. Parts would not last with metal
to metal contact. You need a barrier between
parts to cut down friction, oil is your barrier.
Cooling
Oil also acts as a heatsink for the engine, and as
stated above, you need oil to cut down friction,
if there was no oil the heat caused from friction
would be enough to destroy any engine.
Cleaning
Oil acts in another way, it removes dust
particles that enter the engine, and
some of the carbon build up in the
engine. This is one of the reasons it is
important to change your oil.
24. Lubrication regimes in the engine
The key operating tribological parameter in
any system is the lubricant film thickness
separating the interacting component
surfaces.
It is defined as the relative magnitude of the
lubricant film compared to the combined
surface roughness of the two surfaces, the so-
called film thickness ratio, or parameter, l.
Where h is the film thickness and s is the root mean square
(rms) surface roughness.
27. Function of a lubricant
• Lubricate - Reduce friction
• Cooling - Heat transfer
• Cleaning - Detergency
• Noise pollution - dampening
• Sealing – prevent leakage
• Protection – prevent wear
28. Lubricate – reduce friction
• The effects of friction
• Metal to metal contact
• Leads to wear and tear
• Generates heat
• Results in Power loss
• Lubricant reduces friction by
forming a film
• Reduces ill effect of friction
30. Cooling
• When fuel is burnt in an engine
• 33% is useful power
• 33% removed by cooling water
• 33% by lube oil and radiation
• Lube oil removes heat from all areas
and brings it to the engine sump.
• Improper cooling can lead to over
heating, lead to wear, distortion and
failure.
35. Properties of lubricants
• Kinematic viscosity
• Viscosity index
• Pour Point
• Flash Point
• Total Base Number (TBN)
36. Properties of lubricants
• Kinematic viscosity
• Measure of internal resistance to flow
• “Thickness” of fluid (in laymen terms)
• Decreases with increase in temperature
• Important in lubricant selection
• Increase in used oil indicates oxidation
• Specified at 40˚C and 100˚C
• Measured in Centi Stokes (CSt)
37. Kinematic Viscosity -
Recommendations
• Low Viscosity oils used
• High speeds
• Low pressure
• Low temperature
• High Viscosity oils used
• Low speeds
• High pressure
• High temperature
38. Properties of lubricants
• Viscosity index
• Measure of fluids change of viscosity
with temperature.
• Empirical number
• Higher the VI lower will be the
change of viscosity with temperature
• Indicator of temperature range of
operations
39. Properties of lubricants
• Pour Point
• Lowest temperature at which the fluid
will flow
• Indicates lowest operating
temperature
• Measured in ˚C
40. Properties of lubricants
• Flash Point
• Lowest temperature at which the vapor
above the liquid will ignite under flame
• Indicated safe maximum temperature of
operation.
• Indicator of volatility
• Test method - COC and PMCC
• Measured in ˚C
41. Properties of lubricants
• Total Base Number (TBN)
• Measured the acid neutralizing
reserve in oil.
• Important for deciding discard of oil
• Decreases due to
• Oxidation of oil
• Water contamination
• Fuel contamination
• Measured in Mg KOH/gm of oil
42. Lab Tests - for lubricants
ASTM D 445
ASTM D 2250
ASTM D 97
ASTM D 92 (COC)
ASTM D 93 (PMCC)
ASTM D 664
Kinematic viscosity
Viscosity index
Pour Point
Flash Point
Total Base Number
(TBN)
43. What are additives
Lubricant additives
classified on their functional capability
Enhance existing property
Suppress undesirable property
Impart new property
44. What are additives
– What they do in Engine Oils
Protect metal surfaces
- (rings, bearings, gears, etc.)
Extend the range of lubricant
applicability
Extend lubricant life
46. Surface Protective additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Anti wear & EP Agent
Reduce friction & wear.
Prevent scoring & seizure
ZDDP, Organic Phosphates, acid
phosphates, organic sulfur and chlorine
compounds etc.
Chemical reaction with metal surface
and forms a film.
Prevents metal-to-metal contact
47. Surface Protective additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Corrosion and Rust Inhibitor
Prevent corrosion and rusting of the
metallic parts in contact with lubricant
ZDDP, Metal phenolates, Basic Metal
sulphonates, fatty acid & Amines.
Preferential adsorbtion of polar
constituent on metal surface.
Provide protective film
Neutralize corrosive acids
48. Surface Protective additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Detergents
Keep surface free of deposits
Metallo organic compounds of Sodium,
Calcium and Magnesium phenolates
Phosphonates and sulphonates
Chemical reaction with sludge and
varnish percursors to neutralize them
and keep them soluble
49. Surface Protective additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Dispersant
Keep insoluble contaminants
dispersed in the lubricant
Alkylsuccinimides, alkylsuccinic esters
and mannich reaction products
Contaminants are bonded by polar
attraction to dispersant molecules.
Prevented from agglomerating
Kept in suspension due to solubility of
dispersant
50. Surface Protective additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Friction modifier
Alters coefficient of friction
Organic fatty acids and amides.
Lard Oil, high molecular weight
organic phosphorus.
Phosphoric acid esters
Preferential adsorbtion of surface
active materials
51. Performance additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Pour Point Depressant
Enable lubricant to flow at lo
temperature
Alkylated naphthalene
Phenolic polymers, Ploymethacrylates
Maleate/fumerate copolymer esters
Modify wax crystal formation to reduce
interlocking
52. Performance additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Seal swell Agent
Swell elastomeric seals, gaskets
Organic phosphates
Aromatic hydro carbons
Chemical reaction with with elastomer
to cause slight swell.
53. Performance additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Viscosity modifier
Reduce the rate of viscosity change
with temperature
Polymers and copolymers of olefins,
methacrylates, dienes
Alkylated styrenes.
Polymers expand with increasing
temperatures
This counteract oil thinning
54. Performance additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Antifoamant
Prevent lubricant from forming a
persistent foam
Silicone polymers
Organic copolymers
Reduce Surface tension to speed
collapse of foam
56. Performance additives
- Automotive Lubricants
Additive type
Purpose
Typical
compounds
Function
Metal deactivator
Reduce catalytic effect of metals on
oxidation rate
Organic complexes containing
nitrogen or sulfur
Amines, sulphides and Phosphates
Forms inactive film on metal surfaces
by complexing with metallic ions
58. API GROUPS
Group I- Solvent
refined. (Older
technology)
Group II-
Hydrocracked (most
oils)
Group III- Further
hydrowaxed (Castrol
Syntec)
Group IV-
Polyalphaolefin (PAO),
Mobil 1
61. Effect of Temperature on Viscosity
• Viscosity is a
measure of a
fluid’s resistance
to flow (“how
thick it is”)
• Viscosity of a fluid
is a function of
temperature
0 50 100
0
20
40
60
80
100
120
140
160
180
200
TEMPERATURE (C)
KINEMATIC
VIS
COS
ITY
c
S
t
uh….a liquid gets thinner as it
gets hotter!!!)
62. Fluid
Molecules
Why is Friction Reduced?
There is less “friction” between fluid
molecules moving over each other than
between the two surfaces moving across each
other.
63. The formation of an oil wedge in a plain bearing
Metal-to-metal contact Oil wedge supports load
Connecting Rod Example
64. SYNTHETIC OILS MINERAL OILS
Large Molecules thicken at low temp
Small molecules
vaporize at high temp
All molecules same size
H-C-C-C-C-C-H
H H H H S
H H
O N H
Impurities oxidize
C10H20
C10H20
C10H20
C10H20
67. Major specifying
organizations
• SAE – Society of Automotive Engineers
(USA)
• API - American Petroleum Institute
• US Military Specs – US - MIL – 2104 -
• CCMC – European Specification
• ISO – International Standard Organization –
ISO 3348
• NLGI – National Lubricating Grease Institute
68. SAE viscosity grades for
engine oils
Designated
• With corresponding viscosity
• For high temperature application
• Warmer areas/regions
• SAE 20
• SAE 30
• SAE 40
• SAE 10
• SAE 50
• SAE 60
69. SAE viscosity grades for
engine oils
Designated
• With corresponding viscosity
• For low temperature application
• Colder areas/regions
• SAE 0 W
• SAE 5 W
• SAE 10 W
• SAE 15 W
• SAE 20 W
• SAE 25 W
70. SAE viscosity grades for
Mono grades - Engine Oils
Mono grades are designated
with single SAE number
SAE 10, 20, 30, 40, 50
• SAE 5W,10W, 15W,20W,25W
• Can be used either in summer season
or in winter seasons.
• Gradual shift to multi grades.
• Shift also due to lower oil
consumption by multi grades
• Available as Engine oil and Gear Oils
71. SAE viscosity grades for
Multi grades - Engine Oils
Multi grades are designated
with two SAE number
Widely in use today
• SAE 10w/30, 15w/30, 25w/50
• SAE 5W/30, 20W/40
• Suitable for use in winter and summer
months or seasons
• Available in Engine oils & Gear oil
72. SAE Crankcase Oil - Viscosity
classification – Winter Service
Low temp viscosities High temp viscosities
SAE
Viscosity
Grade
Engine cranking
Max. cPs at Temp
(˚C)
Max. Temp for
pumping viscosity
of 60,000 cP(˚C)
Vis. at 100˚C,
cSt
High shear
(cP) 150˚C
& 106 S-¹
Min
Min Max
Winter Service
0W 6200@ -35 -40 3.8 - --
5W 6200@ -30 -35 3.8 -
10W 7000@ -25 -30 4.1 -
15W 7000@ -20 -25 5.6 -
20W 9500@ -15 -20 5.6 -
25W 13000@ -10 -15 9.3
73. SAE Crankcase Oil - Viscosity
classification – Summer Service
Low temp viscosities High temp viscosities
SAE
Viscosity
Grade
Engine
cranking Max.
cPs at Temp
(˚C)
Max. Temp for
pumping
viscosity of
60,000 cP(˚C)
Vis. at 100˚C, cSt High shear
(cP) 150˚C &
106 S-¹ Min
Min Max
Summer Service
20 -- - 5.6 <9.3 2.6
30 -- - 9.3 <12.5 2.9
40 -- - 12.5 <16.3 3.5
40 -- - 12.5 <16.3 3.7
50 -- - 16.3 <21.9 3.7
60 -- - 21.9 <26.1 3.7
74. API Automotive Gasoline Engine
Service Categories – “SA, SB,…”
Category Related Ind
Definitions
Engine Test Requirements
SA Straight Min None
SB Inhibited only CRC L-4 Sequence IIA Sequence IIIA
SC 1964 Models CRC L-38
Sequence IV
Sequence IIA
Sequence V
Sequence IIIA
Fuel -1% S
SD 1968 Models CRC L-38
Sequence IV
Caterpillar L-1
Sequence IIB
Sequence VB
Caterpillar IH
Sequence IIIB
Falcon Rust
SE 1972 Models CRC-L-38
Sequence IIID
Sequence IIB
Sequence VC
Sequence IIIC
Sequence VD
SF 1980 Models CRC-L-38
Sequence IIIE
Sequence IID
Sequence VD
Sequence IIID
75. API Automotive Gasoline Engine
Service Categories – “SA, SB,…”
Category Related Ind
Definitions
Engine Test Requirements
SG 1989 Models CRC-L-38
Sequence VE
Sequence IID
Caterpillar IH2
Sequence IIIE
SH 1994 Models CRC-L-38
Sequence VE
Sequence IID Sequence IIIE
Category SA, SB, SC, SD, SE,SF,SG,SH have been declared as obsolete.
SJ 1997 Models CRC-L-38
Sequence VE
Sequence IID Sequence IIIE
SL 2001 Models Sequence IIIF
Sequence VIII
Sequence IVA Sequence VG
SM 2004 Models Sequence IIIG
Sequence VIII
Sequence IVA Sequence VG
Category SJ, SL, SM, are currently valid.
76. API Automotive Diesel Engine
Service Categories – “CA, CB,…”
Category Related
US Mil spec
Engine Test Requirements
CA MIL-L-2104A CRC L-38 Caterpillar L-1 Fuel – 0.4% S
CB MIL-L-2104A
Supplement 1
CRC L-38 Caterpillar L-1 Fuel – 0.4% S
CC MIL-L-2104B
MIL-L-46152B
CRC L-38 Sequence IID Caterpillar IH2
CD MIL-L-2104C/D/E,
MIL-L-45199B,
Series 3
CRC L-38 Caterpillar I G2
CD-II MIL-L-2104D/E
2 stroke Hvy Dty
CRC L-38 Caterpillar 1 G2 Detroit Diesel
6V53T
CE None CRC L-38
Mack T-6
Caterpillar 1 G2
Mack T-7
Cummins NTC 400
CF None CRC L-38 Caterpillar 1M-PC
77. API Automotive Diesel Engine
Service Categories – “CA, CB,…”
Category Related Ind
Spec
Engine Test Requirements
CF-2 None CRC L-38 Detroit Diesel 6V92TA Caterpillar 1M-PC
CF-4 None CRC L-38
Mack T-7
Cummins NTC-400 Caterpillar 1K
CG-4 None CRC L-38
Mack T-8
Sequence IIIE
RFWT
Caterpillar 1N
CH-4 None Mack T8E
RFWT
Sequence IIIE
Mach T-9
Caterpillar 1P, 1K
Cummins M 11
CI-4 None RFWT
EOAT
Cummins M11 EGR
Mack T-8E, T-10
Caterpillar 1R, 1K
Sequence IIIF
CI-4Plus None RFWT
EOAT
Cummins M11 EGR
Mack T-8E, T-10,T-11
Caterpillar 1R, 1K
Sequence IIIF
CA to CE obsolete; CF onwards are currently valid
78. ISO 3448 – Kin Vis - CSt 40˚C
vs SUS 100˚F (40˚C)
Midpoint Minimum Maximum SUS 100˚F
VG 2 2.2 1.98 2.42
VG 3 3.2 2.88 3.52
VG 5 4.6 4.14 5.06
VG 7 6.8 6.12 7.48
VG 10 10 9 11 60
VG 15 15 13.5 16.5 75
VG 22 22 19.8 24.2 105
VG 32 32 28.8 35.2 150
VG 46 46 41.4 50.6 215
