AUTOMOTIVE PPT

1. STUDY OF AUTOMOBILE ENGINE FRICTION AND
REDUCTION TRENDS- EFFECTS OF LUBRICANT
ADDITIVES
PRESENTED BY: Department of Mechanical
SHUBHAM BHASIN Engineering
193718 National Institute of Technology,
Automobile Engineering Warangal

2. CONTENT
 INTRODUCTION
 FRICTION COMPONENTS
 RING PACK FRICTION IN RECIPROCATING ENGINE
 CONNECTING ROD SUBSYSTEM
 VALVETRAIN SYSTEM
 FRICTION AND WEAR REDUCTION TRENDS
 EFECTS OF ADDITIVES ON FRICTION AND WEAR
 POWERTRAIN TECHNOLOGY TO LUBRICANT AND
TRIBOLOGICAL REQUIREMENTS
 CONCLUSIONS AND REFERENCES

3. INTRODUCTION
 Friction is the force resisting the relative motion of solid
surfaces , fluid layers, material elements sliding against
each other.
 Engine friction losses are mainly due to sliding and
rotating parts.
 Frictional loss is attributed to the mechanical losses such
as Direct frictional loss, Pumping loss, Power loss to drive
the components
 Engine lubricants and additive play a vital role in
influencing engine friction power loss.

4.  The mechanical friction is about 4 -15 % of the total energy.
This estimate is not true for very extreme condition such as
idling or very light load where most of the energy of fuel gets
consumed in overcoming friction.
Distribution of total energy in a fired engine

5. FRICTION COMPONENTS
1.) Crankshaft friction
 Main bearings, front and rear bearing oil seals
2. )Reciprocating friction
 Connecting rod bearings, piston assembly
3.) Valve train
 Camshafts, cam followers, valve actuation mechanisms

6.  In piston assembly subsystem , there is frictional loss in piston
skirt liner due to variable tilt and piston slap.
 There is hydrodynamic boundary layer between liner and
piston ring assembly at high speed .
REYNOLDS EQUATION FOR THE RING SLIDER

7. RING PACK FRICTION IN RECIPROCATING
ENGINE
Two types of friction loss peaks that occurs are:
1.)Periodic friction peaks at mid stroke that
corresponds to periods of high sliding velocity in oil
control ring.
 Peak frictional power loss around the top ring near
top centre in the top ring.
2.) Due to reflective inter ring pressure superimposing
to the outward radial force on the ring against the
liner.

8. Frictional power loss contribution in piston ring

9. CONNECTING ROD SUBSYSTEM
 Pressure force is transmitted to the crankshaft through the
connecting rod. The top end is connected to the piston from a
piston pin and pin bosses that are the parts of piston.
 Piston pin is small and it rotates slowly so the hydrodynamic
lubrication is uncertain. So,mixed lubrication should be considered
for piston friction but it is found that variable bending is produced
in the pin.

10. VALVETRAIN SYSTEM
 This system consists of mechanical parts and its function is to
open and close the intake and exhaust valves through
camshaft.
 There are four categories of tribological points and sources of
friction:
(i) camshaft bearing friction
(ii) cam follower interface friction
(iii) rocker arm pivot friction
(iv) friction in oscillatory parts
 Valvetrain friction contribution to mechanical losses is around
15 to 20 percent. It has considerable effect on the efficiency
mainly at lower speeds.

11. FRICTION AND WEAR REDUCTION TRENDS
 By mechanical design of different configurations,
mini geometries, characteristics of main component
.These trends have impact on the relative effect of
the lubrication and material properties like texture of
surface, viscous nature of lubricant.
 Through surface engineering and coatings.
 Lubricant and additive technologies.

12. EFECTS OF ADDITIVES ON FRICTION AND WEAR
 It depend on the lubrication regimes at the prevailing
conditions at the local contacts.
 Component of lubrication system under most warmed- up
conditions are: hydrodynamic (for bearings), mostly boundary
(for valve train, cam-follower), and mixed for the piston/ring-
liner interface.
 Hydrodynamic lubrication(for bearings), mostly boundary (for
valve-train, cam-follower), and mixed lubrication for the
piston/ring-liner interface.

13.  Effectiveness of the different additives—viscosity modifiers
versus friction modifiers—varies at the different components
 Lubricant formulation affects friction generally through:
(a) Shear and temperature dependency of the viscosity
changes with the help of Viscosity Improvers.
(b) Friction modifier additives, that can affect the boundary
friction by forming surface layers with low shear strength.
 The sensitivity of the oil viscosity depends on the temperature
such as viscosity index (V.I.). By controlling the engine oil
temperature, the piston liner friction can be affected. The
friction decreases by 20-30 % through the rise in temperature
of the oil in mid section of the liner.

14.  Additives are the materials that are added to the base oil so
as to improve the properties of the oil.
 Viscosity index improvers are high molecular weight polymers,
additives that are added in less quantity to base oil so as to
decrease the temperature sensitivity. V.I. improvers are
polymethacrylate , styrene butadiene copolymer etc.
 Friction modifiers work by the formation of a slippery layer
on the surfaces, and the layers have minimum shear strength
hence producing a low friction coefficient.
(i) Organic friction modifiers
(ii) Chemically reactive friction modifiers

15. POWERTRAIN TECHNOLOGY TO LUBRICANT AND
TRIBOLOGICAL REQUIREMENTS
 Ignition timing, exhaust gas recirculation (EGR) and diesel
particulate filters have affected the ability of lubricants to
control oil deterioration and soot wear.
 Introduction of bio-based fuels and low sulphur, ash, and
phosphorus lubricants have moved to green convergence with
environmentally friendly fuels and lubricants.
 Next generation engine oil requirements include turbocharger
deposit control. Original equipment manufacturer demand
robust oil with respect to deposit control, oxidation and wear
while maintaining good fuel economy performance.

16. CONCLUSIONS
 Automotive tribology development is a critical enabler for
enhanced engine fuel efficiency, power- train longevity, and
vehicle performance.
 Emerging power-train technologies including gasoline direct
injection (GDI), turbocharged, and hybrid vehicles are
reproving to meet fuel economy which will generate unique
chances for future propulsion systems and lubrication
requirements.
 Alternative lubricant and additive approaches such as low
phosphorous and high molybdenum and anti wear additives
technologies offer great performance benefits for fuel
economy, wear prevention, deposit control and additive
approaches.

17. REFERENCES
1. Holmberg K, Andersson P, Erdemir A. Global energy
consumption due to friction in passenger cars. Tribol Int
47:221–234 (2012)
2. Richardson D. Review of power cylinder friction for diesel
engines. J Eng Gas Turbine Power, Trans the ASME 122(4):
506–519 (2000)
3. Taylor C M. Engine Tribology. Amsterdam: Elsevier Science
Publishers, 1993
4. Moughon L. Effects of piston design and lubricant selection
on reciprocating engine friction
5. Kenbeek D, Buenemann T, Rieffe H. Review of organic friction
modifiers—Contribution to fuel efficiency. SAE Technical
Paper 2000-01-1792, Society of Automotive Engineers,
Warrendale, PA, 2000