Chapter 2 - Lubricating System

8/2/2019 Chapter 2 - Lubricating System

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International Islamic University MalaysiaInternational Islamic University Malaysia

Department of Mechanical Engineering, KulliyyahDepartment of Mechanical Engineering, Kulliyyahof Engineering, IIUMof Engineering, IIUM


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The engine is the source of power for the gasoline poweredThe engine is the source of power for the gasoline poweredvehicle.vehicle.

Hundreds of moving parts within the engine areHundreds of moving parts within the engine are rubbing up against eachrubbing up against each

otherother in order to develop the effective torque at the crankshaft forin order to develop the effective torque at the crankshaft forpropelling the car.propelling the car.

This rubbing creates friction.This rubbing creates friction. Friction is the force that resists motion between two bodies in contact.Friction is the force that resists motion between two bodies in contact.

Therefore, the engine performance will be low due to the developmentTherefore, the engine performance will be low due to the developmentof brake power.of brake power.

While the engine burns A/F mixture in the combustion chamber.While the engine burns A/F mixture in the combustion chamber. High temperature develops at the cylinder wall and piston.High temperature develops at the cylinder wall and piston. Causing the engine overheat.Causing the engine overheat.

Many components might damage.Many components might damage.

Thousands of gallons of air are brought into the engine for every gallon ofThousands of gallons of air are brought into the engine for every gallon ofgasoline consumed.gasoline consumed.

Road dust and dirt are brought in with this air.Road dust and dirt are brought in with this air.

In addition, incomplete combustion adds carbon deposits to the oil.In addition, incomplete combustion adds carbon deposits to the oil.

Water can also come in contact with the oil from humidity in the air andWater can also come in contact with the oil from humidity in the air andfrom gaskets leaking.from gaskets leaking.

Sludge form in the engineSludge form in the engine

Sludge is thick, creamy, and black substance that may stuck the torqueSludge is thick, creamy, and black substance that may stuck the torquedevelopment.development.


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All of these factors can lead to engine failure.All of these factors can lead to engine failure. The lubrication system of an automobile is mostly used forThe lubrication system of an automobile is mostly used for

Lubricate the engineLubricate the engine

Engine oil molecules are like little ball bearings and reduce friction.Engine oil molecules are like little ball bearings and reduce friction.

The oil molecules have a tendency to stick to metal surfaces, butThe oil molecules have a tendency to stick to metal surfaces, buthave less of a tendency to stick to each other.have less of a tendency to stick to each other.

Oil decreases resistance and friction between two sliding bodies,Oil decreases resistance and friction between two sliding bodies,resulting in a reduction of engine wear.resulting in a reduction of engine wear.

CollectingCollecting

Road dust and dirt are brought in with the air.Road dust and dirt are brought in with the air. CleaningCleaning

carbon deposits to the oilcarbon deposits to the oil

Dust from humidity in the airDust from humidity in the air

CoolingCooling

protects the engine from overheating partially and prevent the parts fromprotects the engine from overheating partially and prevent the parts fromdamaging.damaging.

By circulating and delivering lubricating oil to all the moving parts ofBy circulating and delivering lubricating oil to all the moving parts ofthe engine.the engine.

ReRe--circulating oil in the engine of vehiclecirculating oil in the engine of vehicle

To carry off heat.To carry off heat.


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Lubricating system

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Gear pump:Gear pump:

The gear pump has a pair of meshingThe gear pump has a pair of meshing

gears.gears. As the gears unmesh, the spaceAs the gears unmesh, the space

between the teeth fill with the oil frombetween the teeth fill with the oil from

the pump inlet.the pump inlet.

The gear mesh with the pumpThe gear mesh with the pump

wall and forced the oil out throughwall and forced the oil out through

the pump outlet.the pump outlet.


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Rotor pumpRotor pump

The rotor oil pump uses an inner rotor and outer rotor.The rotor oil pump uses an inner rotor and outer rotor.

The inner rotor is driven and drives the outer rotor.The inner rotor is driven and drives the outer rotor.

As the rotor turn, the spaces between the lobes fill with oil.As the rotor turn, the spaces between the lobes fill with oil.

When the lobes of inner rotor move into spaces in the outer rotor,When the lobes of inner rotor move into spaces in the outer rotor,

Oil is forces out through the pump outlet.Oil is forces out through the pump outlet.


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Engine Oil SealsEngine Oil Seals During engine operation, the pistons are rapidly moving up andDuring engine operation, the pistons are rapidly moving up and

down.down. Engine oil is also moving up and down with the pistons.Engine oil is also moving up and down with the pistons.

Not only does engine oil lubricate, cool, and clean; it also sealsNot only does engine oil lubricate, cool, and clean; it also sealsbetween vital components.between vital components. Engine oil seals between pistons and the cylinder walls to reduce blowEngine oil seals between pistons and the cylinder walls to reduce blow--

by.by. BlowBlow--by is the gas that escapes the piston rings and into the crankcase.by is the gas that escapes the piston rings and into the crankcase.

Engine oil acts as a seal between components that are separatedEngine oil acts as a seal between components that are separatedby gaskets.by gaskets. For example, you should put a thin film of oil on the oil filter gasketFor example, you should put a thin film of oil on the oil filter gasket

before installation to seal the connection between the filter and engine.before installation to seal the connection between the filter and engine.


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Overfilling OilOverfilling Oil

Engine oil contains detergents to help clean particlesEngine oil contains detergents to help clean particles

and other materials in the engine, similar to soap in aand other materials in the engine, similar to soap in a

washing machine.washing machine.

If the engine overfills with engine oilIf the engine overfills with engine oil, engine will get air, engine will get air

bubbles.bubbles.

Air does not have much of a lubricating ability.Air does not have much of a lubricating ability.

And adding too much oil can increase oil pressure causingAnd adding too much oil can increase oil pressure causingfailure to various seals and gaskets.failure to various seals and gaskets.


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Properties of the lubricating oilProperties of the lubricating oil Proper viscosityProper viscosity

Viscosity indexViscosity index

Viscosity numbersViscosity numbers

Multiple viscosity oilMultiple viscosity oil

Resistance to carbon formation and oil oxidationResistance to carbon formation and oil oxidation

Corrosion and rust inhabitorsCorrosion and rust inhabitors

Foaming resistanceFoaming resistance

Detergent dispersantsDetergent dispersants

Extreme pressure resistanceExtreme pressure resistance

Energy conserving oilEnergy conserving oil

Synthetic oilSynthetic oil


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Proper viscosityProper viscosity Viscosity is defined as the resistance to flow.Viscosity is defined as the resistance to flow.

The higher the viscosity number the thicker the oil.The higher the viscosity number the thicker the oil.

A low viscosity oil is thin and flows easilyA low viscosity oil is thin and flows easily

While, a high viscosity oil is thicker. It flows more slowlyWhile, a high viscosity oil is thicker. It flows more slowly

It is thin enough when the engine is cold and thick enoughIt is thin enough when the engine is cold and thick enoughwhen the engine is warms up.when the engine is warms up.

Light oil is used in cold climates and heavier oil is usually usedLight oil is used in cold climates and heavier oil is usually usedin warmer climates.in warmer climates.

When the engine is cold the oil must be thin enough to get toWhen the engine is cold the oil must be thin enough to get toall of the components, but when the engine warms up the oilall of the components, but when the engine warms up the oilmust not be too thin as to enhance engine wear.must not be too thin as to enhance engine wear.

This is why multiThis is why multi--grade oils have become so populargrade oils have become so popular they canthey canfluctuate their viscosity with temperature changes.fluctuate their viscosity with temperature changes.


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Viscosity indexViscosity index

How much viscosity of an oil changes withHow much viscosity of an oil changes with

temperature.temperature.

A single viscosity oil could be too thick at lowA single viscosity oil could be too thick at low

temperatures and very thin at high temperaturestemperatures and very thin at high temperatures

ViscosityViscosity--Index (VI) improvers are added to engineIndex (VI) improvers are added to engine

oil so its viscosity stays nearly the same, hot or cold.oil so its viscosity stays nearly the same, hot or cold.


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Energy ConservingEnergy Conserving Energy conserving oils have special additives (friction modifiers)Energy conserving oils have special additives (friction modifiers)

which increased the oil additives to lower friction betweenwhich increased the oil additives to lower friction betweencomponents.components.

By lowering the friction, the engine becomes more efficient which inBy lowering the friction, the engine becomes more efficient which inturn improves fuel economy.turn improves fuel economy.

There are two types of modifiers.There are two types of modifiers.

One is chemical that dissolves completely in the oilOne is chemical that dissolves completely in the oil

The other uses powdered graphite or molybdenum held in suspension inThe other uses powdered graphite or molybdenum held in suspension inthe oil.the oil.

There are two categories of energyT

here are two categories of energy--conserving (EC) engine oilsconserving (EC) engine oils EC I and EC IIEC I and EC II

An oil labeled ECII provides a better fuelAn oil labeled ECII provides a better fuel--economy improvement thaneconomy improvement thanan ECI.an ECI.


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Synthetic OilSynthetic OilSynthetic oils are formulated from various chemicals and hydrocarbonsSynthetic oils are formulated from various chemicals and hydrocarbonsto improve engine service and viscosity ratings.to improve engine service and viscosity ratings. Synthetic oils have many pros and cons.Synthetic oils have many pros and cons.

Advantages of Synthetic OilAdvantages of Synthetic Oil Improves fuel mileage through increased lubricating qualitiesImproves fuel mileage through increased lubricating qualities--how explain.how explain.

Increases stability with less viscosity changes as temperatures fluctuate.Increases stability with less viscosity changes as temperatures fluctuate.

Maintains lubricating qualities for up to 25,000 miles.Maintains lubricating qualities for up to 25,000 miles.

Disadvantages of Synthetic OilDisadvantages of Synthetic Oil Higher cost per quart of oil.Higher cost per quart of oil.

Has a poor break in quality due to its high lubricating qualities.Has a poor break in quality due to its high lubricating qualities. Usually not recommended for brand new engines.Usually not recommended for brand new engines.

Most manufacturers still require regular oil change intervals.Most manufacturers still require regular oil change intervals.

With the various advantages and disadvantages the decision of usingWith the various advantages and disadvantages the decision of usingsynthetic oil needs to be made by you and your vehicle manufacturer.synthetic oil needs to be made by you and your vehicle manufacturer. It is important to check the manufacturers warranty when consideringIt is important to check the manufacturers warranty when considering

synthetic oils.synthetic oils.


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Viscosity NumbersViscosity Numbers SAE rates engine oil viscosity.SAE rates engine oil viscosity.

Common viscosity ratings are SAE 10, SAE 30, SAE 5W30, SAECommon viscosity ratings are SAE 10, SAE 30, SAE 5W30, SAE

10W30, SAE 10W40, and SAE 20W50.10W30, SAE 10W40, and SAE 20W50. An oil that has two numbers in the rating is called a multiAn oil that has two numbers in the rating is called a multi--grade oil.grade oil.

MultiMulti--grade oils such as SAE 20W50 have been tested at variousgrade oils such as SAE 20W50 have been tested at varioustemperatures, and thus, can be used in a wide range of climates.temperatures, and thus, can be used in a wide range of climates.

5W30 oil acts like SAE 5 when cold and SAE 30 when warm.5W30 oil acts like SAE 5 when cold and SAE 30 when warm.

The W in the SAE rate engine oil viscosity stands for winterThe W in the SAE rate engine oil viscosity stands for winter

The higher the number, the thicker the oil.The higher the number, the thicker the oil.

The most common engine oil viscosity rating for newer vehicles isThe most common engine oil viscosity rating for newer vehicles is5W30, but always check the owners manual for the manufacturers5W30, but always check the owners manual for the manufacturersrecommendations.recommendations.

Viscosity rating: reflect the oils ability to flow at variousViscosity rating: reflect the oils ability to flow at varioustemperatures.temperatures.


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Servics rating of oil:Servics rating of oil:

SF oil: It provides more protection againstSF oil: It provides more protection against

sludge, varnish wear, oil screen plugging, andsludge, varnish wear, oil screen plugging, andengine deposites.engine deposites.

SG oil: It provides better control of engineSG oil: It provides better control of engine

deposites, oil oxidation, engine wear, and rustdeposites, oil oxidation, engine wear, and rust

and corrosion.and corrosion.


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How does the sludge form and what are the possible waysHow does the sludge form and what are the possible waysto prevent the formation of sludge ?to prevent the formation of sludge ?

Formation of Sludge:Formation of Sludge: Water collects in the crankcase in two ways.Water collects in the crankcase in two ways.

First, water forms as a product of combustion and enter as blowFirst, water forms as a product of combustion and enter as blowby.by.

The lower part of the engine in which the crankshaft rotates,The lower part of the engine in which the crankshaft rotates,including the lower section of the cylinder block and the oilincluding the lower section of the cylinder block and the oilpan.pan.

Second, the crankcase ventilation system carries air through theSecond, the crankcase ventilation system carries air through thecrankcasecrankcase

Sludge forms during homeSludge forms during home--toto--workwork--toto--home driving.home driving.

This shortThis short--trip starttrip start--andand--stop operation never allows thestop operation never allows theengine to worm up and reach normal operating temperature.engine to worm up and reach normal operating temperature.

The water remains in the engine and forms sludgeThe water remains in the engine and forms sludge


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Ways to prevent the sludge formationWays to prevent the sludge formation

The vehicle must be driven long enough toThe vehicle must be driven long enough to

reach normal operating temperaturereach normal operating temperature So, the water in the crankcase vaporizesSo, the water in the crankcase vaporizes

This may requires trips of 16 km or longer in winterThis may requires trips of 16 km or longer in winter

Change the engine oil frequently.Change the engine oil frequently.


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What are the problems that could exist to the engine due to overfillingWhat are the problems that could exist to the engine due to overfilling

the lubricating oilthe lubricating oil explain ?explain ?

By lowering the friction, the engine becomes more efficient which inBy lowering the friction, the engine becomes more efficient which in

turn improves fuel economyturn improves fuel economy explain what are the possible ways toexplain what are the possible ways to

improve the engine fuel economy.improve the engine fuel economy.

Define the viscosity index. Write the name of a multi grade viscosityDefine the viscosity index. Write the name of a multi grade viscosity

index and state what do you meant by the number that are used beforeindex and state what do you meant by the number that are used before

and after of W according to SAE.and after of W according to SAE.

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Chapter 2 - Lubricating System

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