This document discusses the tribological aspects of automotive engine components. It covers topics such as the introduction to tribology, factors affecting tribological performance, lubrication regimes, importance of engine tribology, tribological approaches for automotive components, frictional losses in components, lubrication regimes in components, and lubricant additive technologies. The key engine components discussed are piston rings, engine bearings, valve train, and cam followers. The document explains the lubrication challenges with these components and potential methods to reduce friction and wear such as surface coatings, oil additives, and design modifications.

1. Tribological Aspects of
Automotive Engine
-Submitted by
N.V.A.S.M.SASTRY (9820010002)
G.HEMANTH SAI KUMAR(9820010003)
N.NITHISH GOWD(9919010004)
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2. TOPICS TO
BE COVERED
• Introduction
• Aspects Of Tribology
• Factors Affecting The Tribological
Performance
• Lubrication Regimes
• Importance Of Engine Tribology
• Tribological Approach For Few Automotive
Components
• Frictional Losses In Various Engine
Components
• Lubrication Regimes In Various Engine
Components
• Lubricant Additive Technologies
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3. REFERENCES • AUTOMOTIVE TRIBOLOGY –By Jitendra
Kumar Katiyar,Shantanu Bhattacharya,Vinay
Kumar Patel,Vikram Kumar
• https://www.researchgate.net/publication/336355785_Int
roduction_of_Automotive_Tribology
• Automobile engine tribology — approaching the surface
M. Priest ), C.M. Taylor
• https://www.epfl.ch/labs/tic/wp-
content/uploads/2018/10/A5.pdf
• Tribology for Greener Combustion Engines
• https://uu.diva-
portal.org/smash/get/diva2:1161025/FULLTEXT01.pdf
• Tribological aspects of Internal combustion engine
Ashish Soni 1, Ramjee singh Prajapati 2
• https://www.irjet.net/archives/V4/i9/IRJET-V4I978.pdf 3

4. Introduction • Tribology
– Greek word “Tribos” which means“rubbing” or to rub
– “Ology” means “the study of’’
• Tribology means
– “the study of rubbing of two materials”
• Exist’s at the interface of two materials which are in
relative motion this causes friction at the interface.
• Heat is generated between two mating surfaces which
causes wear on surfaces either one or both the materials.
• Lubricant is used to reduce the friction in between the
surfaces
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5. Aspects of tribology
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6. Factors
affecting the
tribological
performance
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7. Lubrication regimes
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1.Boundary lubrication
2.Mixed lubrication
3.Hydrodynamic /thick film lubrication
4.Elasto-hydrodynamic/thin film lubrication

8. Importance of
Engine
Tribology
We have to improve the tribological aspects of an engine
for the following _
• Reduction in the fuel usage
• To increase the output power
• To reduce the consumption of the oil
• To reduce some of the harmful exhausts
• To improve the durability, reliability, and engine life.
• To reduce the maintenance .
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9. Piston ring
assembly
• The piston rings are very complicated in tribological
aspects since there is a very large variation in speed,
load, temperature and availability of lubricant.
• The lubrication regimes at piston rings and cylinder
wall interface is boundary, mixed,
elastohydrodynamic and hydrodynamic, all in one
engine cycle As the piston assembly moves from bottom
to the top, lubrication regime also changes.
• It is full film lubrication at the bottom dead center,
mixed in the middle of the stroke, and boundary
lubrication at the top dead center
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10. wear mechanisms in
piston-ring/cylinder
contact
• The wear between the piston rings and cylinder contact
is usually of three types :
• 1.Abrasion
2.Adhesion
3.Tribochemical wear
• Abrasion-this is due to the hard residues in the
lubrication oil.
• Adhesion-this is due to the insufficient lubrication,
more heat is generated and removal of the material is
in very small scale.
• Tribochemical wear-This is due to the chemical
reactions between the fuel, lubrication and piston
rings.
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11. Engine
bearing
• Crankshaft, camshaft and connecting rod are supported
by engine’s journal bearing,which rotates during engine
operation.
• The lubrication of bearings is by jet trespass or by
fleeting the lubricant through the shaft holes.
• The initial wear of bearings is very slow under
lubricated conditions of engine operation.
• If the crankshaft is misaligned or there are contaminants
present in lubricant, then excessive wear takes place.
• Journal bearing tribology is a complex issue of
thermal effects, lubricant supply, dynamic loading
and elasticity of the surroundings
• The lubrication of engine bearings is assumed
entirely to be in hydrodynamic regime. 11

12. Valve Train • Friction is a very important parameter for the selection
of valve-train among the three types.
• Roller follower is used in the valve train,because it can
greatly reduce the friction
• since roller contact contributes lower coefficient of
friction compared to sliding contact.
• Friction contribution of the valve systems is a small
fraction (10%) of mechanical losses compared to piston
assembly (50%).
• The coefficient of friction is reduced by introduction of
friction modifier additives such as molybdenum di
thiocarbamate (MoDTC) into the lubricating oil
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13. Cam
follower
• The lubrication of cam follower interface is very
difficult in the valvetrain system.
• The cam follower operates under boundary
lubrication regime .
• wear resistant lubricant additives such as zinc di-alkyl
di-thio-phosphate (ZDDP) are added into the
lubricating oil.
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14. Frictional losses in various engine
components
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15. Methods to
reduce
tribological
problems in
piston ring
assembly
Design changes
• One method of design to reduce frictional force
is to reduce the piston ring tension.
• But more reduction in the piston ring tension
may lead to blow by of the combustion gases.
• Another method to reduce wear is done by
optimising the thermal management to control
the engine oil film temperature.
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16. Surface
engineering
• Different coatings can be used on the piston rings to
improve its resistance to wear like- DLC coatings,
MoS2,
• textured sliding surfaces.- Rather than honing of the
cylinder bore , we can use laser texturing to create
dimples that improve Hydrodynamic lift and also act
as oil reservoirs at starved lubrication.
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17. Contamination
of lubricants
and its effects
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Lubrication

18. Lubricant and
additive
technologies
• Reducing the viscosity of engine oil could lead
to fuel economy improvements of 2-3% .
• But Typically 10-15 additives are present in an
engine oil some of them are-
1. Viscosity index improvers,
2. Friction modifiers,
3. Anti-wear additives
4. extreme pressure (EP) ,
5. anti-oxidants,
6. detergents,
7. dispersants
8. corrosion-inhibitors.
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19. Lubrication regimes in various
engine components
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20. Thank you
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