5.lubrication

LUBRICATIONLUBRICATION
ref-kirpal singh vol -page no-193ref-kirpal singh vol -page no-193

 Friction generates heat
 Some part of energy applied in
rubbing the two surfaces is thus lost
 It is essential to reduce friction
 The fluids which minimize friction
are called lubricants
 The main purpose of a lubricant is to
save mechanical energy

Functions of lubricating oilFunctions of lubricating oil
 Reduces friction between the moving parts
 Reduces wear of the moving parts as far as
possible
 Acts like a cooling medium
 Reduces noise between striking surfaces
 To provide sealing action
 To provide cushioning effect
 To provide cleaning action

 Viscosity – high viscosity index (VI)
 Petroleum lube oils – VI - 100-100
 Can be increased to 120-130 by means of additives
 Physical stability
 Chemical stability
 Resistance against corrosion
 Flash point – should be high
 Cleanliness
 Resistance against extreme pressure
Requirements of lubricantsRequirements of lubricants

Types of lubricantsTypes of lubricants
According their origin oils are classified as followsAccording their origin oils are classified as follows
 Animal oils:Animal oils:
Animal oils: obtained from Animal fat, Easily oxidizedAnimal oils: obtained from Animal fat, Easily oxidized
and become gummy after some useand become gummy after some use
 Vegetable oilsVegetable oils
produced from Seeds ,fruits of plants, trees etc. Easilyproduced from Seeds ,fruits of plants, trees etc. Easily
oxidized and become gummy after some useoxidized and become gummy after some use

 Mineral oilsMineral oils
derived from petroleumderived from petroleum
Following are advantages over above two oilsFollowing are advantages over above two oils
Greater chemical stability at higher temperturesGreater chemical stability at higher tempertures
More plentiful and cheaperMore plentiful and cheaper
 Synthetic lubricantsSynthetic lubricants
Examples:silicon fluids,poly glycol ethers etcExamples:silicon fluids,poly glycol ethers etc
Following are advantages over mineral oilsFollowing are advantages over mineral oils
Higher Considerably less oil consumptionHigher Considerably less oil consumption

 Greases: they are suspension of metallic soapsGreases: they are suspension of metallic soaps
dispersed in lubricating oil.dispersed in lubricating oil.
 These are used where retention of liquid lubricants isThese are used where retention of liquid lubricants is
difficult and where high temperatures are encountereddifficult and where high temperatures are encountered
eg: in axleseg: in axles
 Solid lubricants – Graphite is used as cylinderSolid lubricants – Graphite is used as cylinder
lubricant and ,it is stable at high temperature and lowlubricant and ,it is stable at high temperature and low
coefficient of friction. Use of graphite is that it fill thecoefficient of friction. Use of graphite is that it fill the
pores of the metal and makes it friction free.pores of the metal and makes it friction free.

Viscosity ratingViscosity rating
 According to The Society of Automotive Engineers
(SAE)
 0W,5W,10W,20W,25W – for winter use
 10,15,20,30,40,50,60,80,100,150,200,300 – for summer
use
 Multigrade oils – 10W/30
 First Number in the oil weight represents the oil's viscosity at 0First Number in the oil weight represents the oil's viscosity at 0
degrees F(-18 ºC). The lower the first number in an oil's weight, thedegrees F(-18 ºC). The lower the first number in an oil's weight, the
thinner it is at low temperatures. Oil that is thinner at coldthinner it is at low temperatures. Oil that is thinner at cold
temperatures is typically better suited for winter driving.temperatures is typically better suited for winter driving.
 The second number, the number after the W, represents oil's viscosityThe second number, the number after the W, represents oil's viscosity
at 210 degrees F(99 ºC). The higher the number, the thicker the oilat 210 degrees F(99 ºC). The higher the number, the thicker the oil
will stay at high temperatures. Thicker oil at high temperatures iswill stay at high temperatures. Thicker oil at high temperatures is
better for summer driving.better for summer driving.

Oil additivesOil additives
The chemical substances which are added to the
lubricating oil either to reinforce some of its natural
properties or to provide it with certain new
properties which it does not possess originally
 Oxidation inhibitors – amines, sulphides or phenols
with metals like tin, zinc or barium
 Corrosion inhibitors - oxidation inhibitors with
metal salts
 Detergents – high temperature deposits – gums and
varnishes
and dispersants – low temp deposits – cold sludge
 Anti scuff additives - to polish moving parts like
piston, cylinder walls, cams etc.,
 Viscosity index improvers
 Anti foaming additives – polyorganosiloxanes

Parts which require lubricationParts which require lubrication
 Main crankshaft bearing
 Big end bearings
 Gudgeon pin bearings
 Piston rings and cylinder walls
 Timing gear
 Camshaft and camshaft bearings
 Valve mechanism
 Electrical equipment

Lubrication systemsLubrication systems
Petroil system
Splash system
Pressure system
Dry-sump system

Petroil systemPetroil system
 Used generally for two-stroke enginesUsed generally for two-stroke engines
 Simplest of all types of lubrication systemsSimplest of all types of lubrication systems
 Certain amount of lubricating oil is mixedCertain amount of lubricating oil is mixed
with the petrol itself (2-3% of oil)with the petrol itself (2-3% of oil)
less: Insufficient lubrication causes damageless: Insufficient lubrication causes damage
to engineto engine
more: excessive carbon depositsmore: excessive carbon deposits

Splash system
Con rod
or
scoop
•Employed for motorcycles
•Cheapest method
•The scoop causes the oil
to splash on the cylinder
walls each time it passes
through its BDC position
•This affects the lubrication
of engine walls, gudgeon
pin, crank shaft bearings,
big end bearings etc

Pressure system of lubricationPressure system of lubrication
 Universally used in modern car enginesUniversally used in modern car engines
 An oil pump takes the oil from the wet sumpAn oil pump takes the oil from the wet sump
through a strainer and delivers it through athrough a strainer and delivers it through a
filter to the mail oil gallery at a pressure offilter to the mail oil gallery at a pressure of
200-400 kPa200-400 kPa

gasoline engine lubrication system.

Dry sump lubricationDry sump lubrication

Oil pumpsOil pumps
Its function is to supply oil
under pressure to the various
engine parts
Generally located inside the
crank case below the oil level

Gear pumpGear pump  Its construction isIts construction is
very simplevery simple
 One gear is drivenOne gear is driven
from cam or crankfrom cam or crank
shaftshaft
 The other gear is freeThe other gear is free
to revolve on its ownto revolve on its own
bearingbearing
 The oil is drivenThe oil is driven
between the gearbetween the gear
teeth from the inletteeth from the inlet
side and forced outside and forced out
the outlet sidethe outlet side
Universally used type pump
It can deliver oil at a pressure
of about 2-4kg/cm2

Rotor oil pump
 The two gears
mesh internally
 The oil is
displaced from
the inlet to the
outlet side in
the same way
as in the gear
pump

The cam shaft rotates the drive shaft which rotates
the inner rotor which turns the outer rotor

Plunger pumpPlunger pump
 The plunger
reciprocates in
the pump body
 While moving up
the plunder sucks
oil from
the inlet
 And while
moving down it
forces out the oil
from the outlet
 Used in splash
system

Vane pumpVane pump
 Vane pumps are used for
liquid transfer applications
 Vanes extend from slots in
the rotor, sweeping liquid
through a cam-shaped
cavity. The vanes provide
very low slip and high
volumetric efficiency.

Oil filtersOil filters
 An oil filter is a device used to
decontaminate oil that contains
suspended impurities.
 A major application is in forming part
of the lubrication system of engines in
which filters are typically detachable
units due to the need for regular service
or replacement.
 The filtration of oil in engines is
essential for enhancing longevity and
performance.

Oil filter systemOil filter system
Obsolete

Types of oil filtersTypes of oil filters

Centrifugal type oil filterCentrifugal type oil filter

Oil pressure gaugesOil pressure gauges
Electrically operated
Oil pressure warning light and switch
Oil pressure warning system

Engine ServicingEngine Servicing
 Automobile service is necessary toAutomobile service is necessary to
keep the motor vehicles in akeep the motor vehicles in a
condition ofcondition of
 SafetySafety
 ReliabilityReliability
 ComfortComfort
 CleanlinessCleanliness
 Performance andPerformance and
Economy

 It includesIt includes
High pressure lubricationHigh pressure lubrication
Power washingPower washing
Wheel alignmentWheel alignment
Wheel balancingWheel balancing
Body and wing repairsBody and wing repairs
Transmission service and testingTransmission service and testing
Repair of automobile engine andRepair of automobile engine and
electrical equipmentelectrical equipment

 By servicing and tuning of theBy servicing and tuning of the
engineengine
Greater powerGreater power
Faster acceleration andFaster acceleration and
High road speedsHigh road speeds
can be obtainedcan be obtained

Types of serviceTypes of service
 Self diagnosed servicesSelf diagnosed services
 LubricationLubrication
 Washing bodyWashing body
 Wing repairsWing repairs
 Repairs of brakes, tyresRepairs of brakes, tyres
 Steering alignment etcSteering alignment etc
 Performance servicesPerformance services
 For correcting engine performance andFor correcting engine performance and
 Electrical troublesElectrical troubles

Procedure of engine serviceProcedure of engine service
 Engine disassemblyEngine disassembly
 Cleaning of partsCleaning of parts
 Inspection of partsInspection of parts
 Condition of engine partsCondition of engine parts

Engine DecarbonizationEngine Decarbonization
 Engine decarbonization is a process utilizingEngine decarbonization is a process utilizing
chemicals to remove soft and semi-hardenedchemicals to remove soft and semi-hardened
gum, varnish, resin and carbon depositsgum, varnish, resin and carbon deposits
from thefrom the air/fuel delivery systemsair/fuel delivery systems andand
combustion chamberscombustion chambers of internal combustionof internal combustion
engines.engines.
 Benefits of the service include improved fuel economy,Benefits of the service include improved fuel economy,
engine performance and reduced emissions.engine performance and reduced emissions.
 This process is performed to reduce or removeThis process is performed to reduce or remove
depositsdeposits
 Recommendations will be time and mileage based.Recommendations will be time and mileage based.

 A wire brush is used to remove heavyA wire brush is used to remove heavy
carbon deposits from cylinder headscarbon deposits from cylinder heads
and valves. {Some special wire brushand valves. {Some special wire brush
operates on an electric drill motor}operates on an electric drill motor}
 Scrapers should be used to clean theScrapers should be used to clean the
piston heads and groovespiston heads and grooves

Nitriding of crank shaftNitriding of crank shaft

 Nitriding is a process that infuses
nitrogen ions into the surface of steel to
increase its surface hardness on a
molecular level.
 Nitriding offers the end-user a uniform
hardened layer without internal stresses,
and that’s what makes it perfect for
crankshafts.

Engine ReboringEngine Reboring
A cylinder is rebored because:A cylinder is rebored because:
1. The piston to cylinder bore clearance1. The piston to cylinder bore clearance
is too largeis too large
2. There are deep scratches, grooves in2. There are deep scratches, grooves in
the bore that hinder cylinder sealingthe bore that hinder cylinder sealing
3. The bore is out round compared to3. The bore is out round compared to
the piston.the piston.

 To increase the power of anTo increase the power of an
engine we can increase theengine we can increase the
cylinder capacity. cylinder capacity.
 The best way to increase theThe best way to increase the
cylinder capacity of an engine iscylinder capacity of an engine is
by physically making eachby physically making each
cylinder a larger diameter. cylinder a larger diameter.

 Engine block reboring meansEngine block reboring means
that the engine block isthat the engine block is
machined to a bigger sizemachined to a bigger size
cylinder.cylinder.
 It smoothes out the bores andIt smoothes out the bores and
makes them like new.makes them like new.

Blow-byBlow-by
 If the cylinderIf the cylinder
becomes oval due tobecomes oval due to
wear some of the gaswear some of the gas
escapes through theescapes through the
piston rings.piston rings.
 The gas which leaksThe gas which leaks
through the pistonthrough the piston
rings is calledrings is called blow-blow-
byby..
 It reduces theIt reduces the
efficiency of an engine.efficiency of an engine.

Effects of piston blow-byEffects of piston blow-by
 The partially burnt A/F mixture
contaminate the lube oil in the
crank case, which may deteriorate
the performance of the engine
lubricating oil
 This A/F mixture may cause an
explosion in the crank case
 Corrosion of engine parts

Crankcase ventilationCrankcase ventilation
 A steady flow of air is carried
through the engine crank case
which carries away the products of
combustion along with it in the
form of vapour or mist.
 Methods
1. Road draft system

Road draft system
The air stream due to motion of the vehicle, and
supplemented by the cooling fan enters the engine
at the top and is then circulated in the crank case
where it carries the vapor after which it comes out
through the outlet and goes into the atmosphere

 The Positive Crankcase Ventilation
valve, or PCV valve, is a one-way
valve that ensures continual
evacuation of gases from inside a
gasoline internal combustion
engine's crankcase.
Positive Crank case ventilationPositive Crank case ventilation

 Fuel and
air saver
technolo
gy
(FAST)

ReferenceReference
 Automobile engineering vol 2 by kirpal singhAutomobile engineering vol 2 by kirpal singh
unit-6-lubrication and lubricants page numberesunit-6-lubrication and lubricants page numberes
193193

5.lubrication

5.lubrication

Editor's Notes

5.lubrication

Editor's Notes

5.lubrication

5.lubrication

Editor's Notes

More Related Content

What's hot

Similar to 5.lubrication

Recently uploaded

5.lubrication

Editor's Notes