2

1. PRINCIPLE OF EXHAUST GAS TURBOCHARGER

In a turbocharged engine, the exhaust gas which would normally be wasted, is used to drive a turbine. The turbine in turn drives a compressor, which draws in air and compresses it and supplies it at a higher pressure to the engine. Due to higher air availability and by supplying more fuel, engine power output can be increased. Higher air availability helps in better combustion, thus leading to reduced fuel consumption and less emission.

Advantages Of Turbocharger

Lowerfuelconsumption Bettertorque characteristics

Lower engine noise Lower emission

Lower weight and a smaller engine package

Reduced power loss at highaltitude

As a result, turbochargers contribute significantly to the protection of the environment and better utilization of energy resources.

3

2. CONSTRUCTION & FUNCTION OF A TURBOCHARGER

Turbocharger (TC) primarily comprises of a compressor section and a turbinesection.Theturbineandcompressorwheelsaremountedona commonshaft,hencetheyrotateasasingleunit.Thissub-assemblyis known as the rotor assembly. The rotor assembly is supported by journals placed inside the central housing.

2.1 TurbineSection

Turbine section consists of the turbine wheel and turbine housing. The pressure energy available in the exhaust gases is converted into Kinetic energy by the turbine housing and is used for rotating the turbine wheel.

2.2 CompressorSection

The compressor consists of the compressor wheel and compressor housing. The compressor wheel draws in air axially and delivers it radially at a higher velocity. The compressor housing converts higher velocity air into higher pressure.

2.3 Central Housing

The central housing consists of all the supporting & sealing components required for the rotorassembly. Journals & thrust plate for supporting rotor assy., and the lubricating oil passages for oil supply&drain.Pistonringsforsealing.

TurbineHousing

TurbineWheel

Piston rings(sealing rings)

Oil feed

Oil drain Heat shield

Axial / Thrustbearing

Radialbearings

Compressorhousing

Compressorwheel

4

3. TURBOCHARGER TECHNOLOGY3.1 Waste Gated Turbocharger

For reasons of improved TC response, turbine housing with a smaller cross sectional area is chosen such that sufficient boost pressure is available at lowerenginespeeds.Partof theexhaust gas isby-passedoncetherequiredboost pressure is reached. This is achieved by opening a valve, operated by a spring loaded diaphragm (actuator assembly) with the help of boost pressure available in the compressor housing or with the help of external vacuum supply.3.2 Variable Turbine Geometry (Vtg)The turbine flow cross-section varies in accordance with the engine ECU demand by variable guide vanes placed in the exhaust gas flow area of the turbine housing. As a result of continuous turbine cross section adjustment to the engine airflow

Actuator assembly /Waste gate

requirements, high engine torque at low speeds and with adequate control strategy ensure a significant improvement of dynamic performance of vehicle. Guide vane control is mostly electronic through a vacuum regulated actuator.3.3 R2S Turbocharger

Regulated two stage turbocharger (R2S). This system uses one low pressure turbocharger and one high pressure turbocharger i.e. two turbochargers for one engine. This technology helps in increasing the engine’s specific power output (power to weight ratio) and also helps in downsizing the engine while meeting the performance requirement.

5

4. NEEDS OF A TURBOCHARGER• Turbocharger components are made from special materials, processesandareprecisionbuilttoworkunderextremeoperating conditions.• However turbocharger needs ADEQUATE CLEAN ENGINE OIL & CLEAN AIR for its proper performance and extended life.

4.1 WHY A TC NEEDS THEM ?• TCrotorassemblyrotatesfrom1,00,000to2,50,000RotationsPer Minute(RPM).• The clearances between the rotor and the journal are extremely small and the parts are machined to very close tolerances (around 0.005 mm).• TCusesfullyfloatingjournals,thatrotateathalfthespeedofthe rotor assembly.• Filteredoilattherequiredpressureisessentialtolubricateandcool the journals.• TheTCcomponentsarebalancedtoveryfinebalancinglimits.• Air / gas entering the compressor and turbine housing travels at very high speeds.

6

5. GUIDELINES FOR TURBOCHARGER USEThe engine manufacturer’s recommendations for operation and maintenance shall be authoritative for the operation of turbocharged engine.Specialattentionshouldbepaidtothefollowing:

5.1 OPERATION RECOMMENDATIONS5.1.1 DO NOT ACCELERATE THE ENGINE IMMEDIATELY AFTER START• Acceleratingtheengineimmediately after start can make the TC to operate at very high speeds with inadequate lubrication which will lead to reduce TC service life.• Engine should not be put under full load immediately after start, it should run at idling speed for a minimumtime(60seconds).

5.1.2 BEFORE SWITCHING OFF THE ENGINE

Allow the engine to run at idle for at least 60secondsbeforetheengineisswitched off.Idlingwillreducetherotorspeedand heat transfer thus ensuring longer TC service life.

Do not accelerate theengine immediately

after starting

Allow the Engine toidle for some time

before it is stopped

7

6. TURBOCHARGER INSTALLATION AND STARTING PROCEDURE

6.1 Use only the correct part number i.e. TC approved by the engine manufacturer.

6.2 CHECK THE TC VISUALLY FOR:

Externaldamages - IfTCisfounddamaged,donotuseit.

Correctorientation - IfTCorientationisnotcorrect,pleasecontactTEL / TEL ASC for assistance.

Old TC (long storage), if TC is rusted, do not use it as-it-is. Necessary cleaning,prelubricationandinspectionoftheTCisamustbeforeitsuse.Contact TEL / TEL ASC for assistance.

6.3 TC HANDLING

AsTC isaprecisionequipment, it should be handled with great care. In any case, it should not be dropped.

In case of wastegated / VTG turbocharger, don’t use the actuator control rod for liftingtheTC.

As Wastegated / VTG turbochargers comes with preset actuators, this setting should not be changed. Any changes to the actuator settings will effect engine performance.

6.4 RemovealltheprotectiveplugsfromtheTCbeforefitment.

6.5 EXHAUST CONNECTIONS

Checktheengineexhaustmanifold&itsconnectionstotheTCforcracks &distortionandarefreefromforeignmaterial i.e.coresandparticles, loose nuts, bolts, washers, etc.

Do not use actuatorcontrol rod for lifting

the Turbocharger

8

The exhaust systems should be checked for blockage (damaged pipes, faultyexhaustbrake,chokedsilencer/catalyticconverteretc.,),leakages andtheirproperalignment&support.

6.6 COMPRESSOR CONNECTIONS

Clean the TC compressor outlet to engine intakemanifold connecting pipes, hoses and intercooler for residual engine oil, before new TC is fitted.

Check the connections i.e. pipes forwear, damage, correct alignment,hosesforcracks/ageing.Checkintercoolerforleaks&blockage.Checkthehoseclipsfortheirproperfunctioning.Replacewithrecommended clips wherever necessary.

Checkaircleaner,filterelementsanditsconnectingpipes,hosestothe TCarefreefromforeignmaterial.Airfilterelementsshouldbecleaned/ replaced as recommended by the engine manufacturer.

6.7 OIL INLET AND DRAIN CONNECTIONS

6.7.1Oilinletanddrainpipes,connections to the TC, should be examined for carbon deposits, cracks, distortion, etc., Pipes should be thoroughly cleaned before fitment. If found damaged, it should be replaced.

6.7.2 Ensure that recommended size of oil inletpipe&banjoboltsareused.During replacement care should be taken for proper routing and fitment to avoid excessivestressontheconnection.

Correct oil Wrong oilhole size hole size

9

TURB

OCH

ARG

ER T

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OTI

NG

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RT

POSS

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SES

REM

EDIA

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NS

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tsCh

eck&

replacetheelem

entaccordingto

engin

emanufacturer'srecommendatio

ns

Restric

tionsin

airintaketo

TC

com

pres

sor i

nlet

Removerestric

tionorre

placetheda

maged

pa

rts i

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e pi

pes,

with

ered

hos

es e

tc.,

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t to

inta

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ldRe

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placeda

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ipe,

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nter

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tc.,

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eak

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nd

TC c

ompr

esso

r / E

x. G

as le

akag

es

atth

eturbineou

tletcon

necti

ons.

Check&arrestthe

leakbyreplacing

de

fecti

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s,pipes,gasketsor

tighten

theclam

ps&fa

sten

ersa

sreq

uired

Air l

eak i

n be

twee

n TC

com

pres

sor

&intakemanifold.

Check&arrestthe

leakbyreplacing

de

fectivehoses,clips,pipe

s,gaskets,

intercoo

lero

rtightenthecla

mps&

fasten

ersthe

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sreq

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obje

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eng

ine

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ust

man

ifold

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se/

originofthe

objecte

ntry&correctit.

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ricte

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haus

t sys

tem

/ chockedcatalytic

con

verter.

Removerestric

tionorre

placeda

maged

pa

rts,clean

/replacecatalytic

con

verteras

requ

ired

ComplaintEngine lacks power Black exhaust smoke Excess

iveoilconsu

mption Blue / white smoke Turbocharger noisy Oil leak from comp. Oil leak from turbine

10

Exha

ust g

as le

akag

e be

fore

the

TC.

Check&

arresttheleakb

yreplac

ingd

efective

parts,gasketsortightenthefastenersasrequired.

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tionintu

rbocha

rgeroil

drai

n lin

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moverestric

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epipe

s,atjointso

rreplacewith

ered

hosesasreq

uired

Rest

ricte

d en

gine

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nk c

ase

breather/malfunctio

ning

ofcrank

caseven

tilati

onsy

stem

.

Refe

r to

engi

ne m

anuf

actu

rer's

man

ual

andremoverestric

tion(ensurefree

flow

of

gases)&re

placethede

fecti

veparts

Rotorrotati

onnotfree

due

to

thic

k oi

l slu

dge

or c

oke

in

turb

ocha

rger

cen

tral

hou

sing

Chan

geoil&oilfilter,checkEG

Rforc

orrect

operati

on,con

tactTELAutho

rised

service

centersforTCrecti

ficati

on.

Faultyfuelinjectionpum

p&injectors

&itsfi

tmenttoengin

e/faultyEC

U/

defectiveEG

Roperation.

Refe

r to

engi

ne m

anuf

actu

rer's

man

ual a

nd

replaceoradjusta

sreq

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Worn-ou

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ring

, lin

ers,

inte

rnal

eng

ine

prob

lem

s (in

crea

sed

blow

by)

Refe

r to

engi

ne m

anuf

actu

rer's

man

ual a

nd

repa

irasre

quire

d

Dam

aged

act

uato

r ass

y., b

oost

pr

essu

re c

ontr

ol v

alve

stuc

k in

op

enposition

Repl

ace

TC O

R co

ntac

t TEL

Aut

horis

ed

servicecentersforre

ctificati

on.

Actuatorassy,.Operatin

gho

se

punc

ture

d O

R fo

und

disc

onne

cted

Repl

ace

/ con

nect

the

hose

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TEL

Au

thorise

dservicecentersforre

ctificati

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VGTactuatorope

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ound

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11

6.7.3 Use only the recommended gaskets forfitmentoftheTCtotheengine.

Do not apply gaskets sealant (Shellac, Anabond, Grease, etc.,) at the oil inlet and compressorinletconnections.

Do not use thread sealant in the oil supply line.

6.7.4 Beforestartingtheengine,fill-upthe oil feed hole of the TC with clean engine oil to ensure lubrication during engine start-up. Oil filter should be filled with clean engine oil to minimize oil reaching timetoTC.

Replace the engine oil and oil filter, if necessary (adhere to engine manufacturer’s recommendation for correct grade and change periodicity)

Disconnect the TC actuator operating switch / hose (for VTG TCs) during first starting.6.7.5 Disconnect the oil drain joint between turbocharger and crankcase. Cranktheenginewithoutstarting,untiloil flow is observed in the turbocharger oil drain line. A funnel can be used to return oil to the crankcase. Reconnect the oil drain joint.6.7.6 Check the engine oil pressure. Do not run the engine, if oil pressure is found less than the one recommended by the engine manufacturer.

Connect the TC actuator operating switch / hose (for VTG TCs).

Oil in the filter

Do not run the enginewith low engine

oil pressure

Do not apply sealant inGaskets

Pre oil the turbochargerbefore fitment

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6.8 ENSURE NO LEAKAGEWith the engine in running condition, check oil line, air and gas connectionsforleakageandfortheirproperfunctioning.Checkoilinletandreturnlineconnectionforleakages.Ensure that the air cleaner to TC connections are intact. Check air leakages at compressor outlet to inlet manifold.Check exhaust gas leakage at exhaust manifold and at the turbine housing joints.The most common reason for NOISE complaint is small leakage of exhaust gas or compressed air.

CAUTION

Stay away from running Turbocharger (at engine higher RPM)

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7. TC VISUAL INSPECTION PROCEDURE

Check the compressor wheel for Damage.

Damaged – Not O.K Not damaged – O.K

Check the compressor wheel for rubbing with housings.

Rubbing marks – Not O.K No rubbing marks – O.KChecktheshaftforfreerotation.

Nofreerotation–NotO.K Freerotation–O.K

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7.1 PNEUMATIC ACTUATOR ASSEMBLY CHECKING PROCEDURE

ChecktheTCactuatorassemblyforitsproperfunctioningi.e.checkfor damages,tampering,looseoropenconnections.

Checktheshaftforfreerotation.

Excess play – Not O.K Normal play – O.K

NOTE

Fallowthesameinspectionprocedureforturbinesidealso.

3OK

L pipe breakage

Hose puncture

Link welding failure

Flap Open(for pressuretype only)

Control rod damaged

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7.2 VTG TC VACUUM ACTUATOR CHECKING PROCEDURE

Thenormalworkingcondition:

Withtheengineisswitched-off,TCactuatorwillbeinOPENconditioni.e.Actuator control rod length will be maximum.

Whentheengineisswitched-on(whileengineinrunningcondition),TCactuatorcontrolrodwillbeinclosedconditioni.e.Actuatorcontrolrodlength will be minimum.

During theengineoperation theTCactuator control rodmoves freelywithoutrestriction.

VACUUMPUMP

EGRVALVE

ECU

CONTROLSWITCH

ENGINE RPM METER

1

23 4

5

6

7

Engine Switch ‘ON’Condition

Engine Switch ‘OFF’Condition

VACUUMRESERVOIR

VTG TC Vacuum Actuator Not OK:

Symptoms: Vehicle speed is not O.K, Check Engine light is ON.

Diagnosis on the Vehicle:Connecttheenginediagnosticandcheckfor fault code (Ex.: Engine airflow deviation - Not O.K)

16

Checks on vehicle:

Thevacuumhoses forcorrectfitment,Open/damagedhoseswill causeactuatormalfunctioning.

Switchcontrollingvacuumsupplytoactuatorforproperfunctioning.

Thevacuumpumpisfunctioningcorrectly.

Sufficientvacuumsupply istheretoTCactuatorwhiletheengineis in runningcondition.

Checks on TC:

Check if the actuator control rod is proper (ensure that it is not tampered),theadjustingnutsarein place, the control rod is not damaged, rusted, excessively worn-out.

Move the control rod with handconfirmitsmovement is free.

Remarks: If all checks on vehicle found O.K and the TC actuator operation is not O.K i.e. the actuator control rod does not move up when theengine is switched-on andmovesdownwhen theengine is switched-off OR the TC actuator control rod movement is not free - Replace the TC.

17

Complaint: TC Damage

Observations: Blue colour formation on the shaft journal area. Seizure / excessive wear on the journals

Causes: Lack of oil supply

Complaint: TC DamageObservations: Journal oil holes closed partially. Discolouration / glazing marks on shaft journal contact area

Causes:Insufficientoilsupply/Low oil pressure

8. SERVICE RECOMMENDATIONS

PleaseconsultTELASCforanyservicerequirementofaturbocharger,as they only will have necessary tools & equipment, trainedmanpower, genuine parts for proper service andwill offer support for its correct installation&maintenance.

Fordetailsvisit:www.turboenergy.co.in

9. TURBOCHARGER FAILURE ANALYSIS

Years of experience has shown that the largest percentage of turbocharger failures are caused by lubrication problems such as lack of oil, low oil pressure and dirt in oil.

Thesecondlargestpercentageiscausedbyforeignparticleenteringthe compressor / turbine housing sides.