electronic diesel fuel system ( common rail)

8/19/2019 Electronic Diesel Fuel System ( Common Rail)

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COMMON RAIL FUEL INJECTIONCOMMON RAIL FUEL INJECTION

SYSTEMSYSTEM

;JL";L\U V[g0 VMJZ CM,L\UVMO VM8MDMAF., s 0Lh,

f],[XG G\AZ : 15


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Demand On Modern Diesel EngineDemand On Modern Diesel En

gineDevelopmentDevelo

pment

• Low fuel consumptionLow fuel consumption

• Low pollutant emissionsLow pollutant emissions

•

Quiet running enginesQuiet running engines

• Improved engine performanceImproved engine performance


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Common rail !el in"e#tion s$stem and itsCommon rail !el in

"e#tion s$stem and its

!n#tion!n#tion

• Provide the diesel engine with fuelProvide the diesel engine with fuel

• Generate the high pressure needed for fuelGenerate the high pressure needed for fuel

injection and distribute the fuel to theinjection and distribute the fuel to the

individual cylindersindividual cylinders

• Inject precisely correct amount of fuel atInject precisely correct amount of fuel at

exactly the right moment in time.exactly the right moment in time.• In contrast to other injection system CommonIn contrast to other injection system Common

rail fuel injection system is an accumulatorrail fuel injection system is an accumulator

injection system.injection system.


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%o& does a CR s$stem !n#tion'%o& does a CR s

$stem !n#tion'

S u b f u n ! " # n s # f $ C % F & s ' s ! ( )

L o w p r e s s u r e c i r c u i t i g h p r e s s u r e c i r c u i t ! C " w i t h s e n s o r s

C O M M O N R A I L F U E L I N J E C T I O N S Y S T E M


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Low –pressure circuit comprises of:Low –pressure circuit comprises of:

Fuel tank ,Pre-supply pump, Fuel filter, And theFuel tank ,Pre-supply pump, Fuel filter, And therespective connection linesrespective connection lines

#he Common $ail %ub functions#he Common $ail %ub functions


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Low &pressure circuitLow &pressure circuit#he low &pressure circuit is responsible for#he low &pressure circuit is responsible for

transporting the fuel to the high &pressure circuittransporting the fuel to the high &pressure circuit


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%ig( )press!re #ir#!it #omprises*%ig( )press!re #ir#!it #omprises*

%ig( ) press!re p!mp &it( press!re ) #ontrol valve%ig( ) press!re p!mp &it( press!re ) #ontrol valveT(e (ig( ) press!re a##!m!lator +Rail ,&it( t(e rail )T(e (ig( ) press!re a##!m!lator +Rail ,&it( t(e rail )press!re sensor press!re sensor

In"e#tors- andIn"e#tors- and

T(e respe#tive (ig( ) press!re #onne#tion lines.T(e respe#tive (ig( ) press!re #onne#tion lines.



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#he high & pressure circuit#he high & pressure circuit

It is t(e responsi/ilit$ o t(e (ig(It is t(e responsi/ilit$ o t(e (ig(

press!re #ir#!it to generate a #onstantpress!re #ir#!it to generate a #onstant!nvar$ing (ig( press!re in t(e (ig(!nvar$ing (ig( press!re in t(e (ig(

press!re a##!m!lator +t(e rail, and topress!re a##!m!lator +t(e rail, and to

in"e#t t(e !el t(ro!g( t(e in"e#tors intoin"e#t t(e !el t(ro!g( t(e in"e#tors intot(e engine0s #om/!stion #(am/ers.t(e engine0s #om/!stion #(am/ers.


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!C" and sensors!C" and sensors

#he common rail !C" evaluates the signals from the#he common rail !C" evaluates the signals from thefollowing sensors.following sensors.

Cran'shaft & speed sensor( Camshaft sensor(Cran'shaft & speed sensor( Camshaft sensor(

)ccelerator*pedal travel sensor )ccelerator*pedal travel sensor



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#he common rail !C" evaluates the signals from the#he common rail !C" evaluates the signals from thefollowing sensors+following sensors+

,oost & pressure sensor( )ir temperature sensor(,oost & pressure sensor( )ir temperature sensor(

)ir & mass meter( and $ail pressure sensor. )ir & mass meter( and $ail pressure sensor.



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!C" and sensors!C" and sensors#he sensor are responsible for measuring important#he sensor are responsible for measuring important

physical -uantities. #he !C" calculates injected fuelphysical -uantities. #he !C" calculates injected fuel

-uantity( start of injection( duration of injection( and-uantity( start of injection( duration of injection( and

rate of discharge curve( as well supervises the correctrate of discharge curve( as well supervises the correct

functioning of the injection system as a whole.functioning of the injection system as a whole.


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P$! %"PPL P"/PP$! %"PPL P"/P

#ransports fuel from the fuel tan' to the high pressure#ransports fuel from the fuel tan' to the high pressurepump.pump.

)n electric fuel pump is used for this purpose in the )n electric fuel pump is used for this purpose in theC$0I%.C$0I%.

1hen the electric fuel pump is switched off( the supply1hen the electric fuel pump is switched off( the supplyof fuel is interrupted and the engine stops.of fuel is interrupted and the engine stops.

COMMON RAIL FUEL INJECTION SYSTEMCOMMON RAIL FUEL INJECTION SYSTEM

DESIGN DESIGN


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#he electric fuel pump comprises of+#he electric fuel pump comprises of+

2.!lectric /otor 2.!lectric /otor

3.$oller*Cell Pump3.$oller*Cell Pump

4.5on $eturn 6alve4.5on $eturn 6alve


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#he roller cell is#he roller cell isdriven by an electricdriven by an electric

motor.motor.

Its rotor is mountedIts rotor is mountedeccentrically andeccentrically andprovided with slotsprovided with slotsin which movablein which movablerollers are free torollers are free totravel.travel.



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#he rollers are forced#he rollers are forced

against the base plateagainst the base plateby rotation and by fuelby rotation and by fuelpressure .pressure .

#he fuel is#he fuel is

transported to thetransported to theoutlet openings on theoutlet openings on thepump7s pressure side.pump7s pressure side.



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1ear t$pe !el p!mp1ear t$pe !el p!mp

*h( +-( g($*h( +-( g($

h((/ s +-(n b'h((/ s +-(n b'!h( (ngn( .!h( (ngn( .

D(/-(' u$n!!' sD(/-(' u$n!!' s+(!/' 1#1#!#n$/+(!/' 1#1#!#n$/

!# (ngn( s1((+ .!# (ngn( s1((+ . Shu! #2 s b' )($nsShu! #2 s b' )($ns

#f $n#f $n(/(!#)$gn(!..(/(!#)$gn(!..


variantsvariants


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igh* pressure pumpigh* pressure pump

#he pump plunger moves downwards#he pump plunger moves downwards

#he inlet valve opens#he inlet valve opens

#he fuel is drawn in to the pumping element#he fuel is drawn in to the pumping elementchamber8suction stro'e9chamber8suction stro'e9


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)t ,:C( the inlet valve closes )t ,:C( the inlet valve closes

#he fuel in the chamber can be compressed by#he fuel in the chamber can be compressed bythe upward moving plunger.the upward moving plunger.



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)n electromagnet is )n electromagnet isused for pumpingused for pumpingelement switch*off.element switch*off.



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igh* pressure accumulator 8$ail9igh* pressure accumulator 8$ail9%tore fuel%tore fuel

Prevent pressure fluctuationsPrevent pressure fluctuations


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$ail is a forged*steel tube.$ail is a forged*steel tube.

I: is approx.. 2;mmI: is approx.. 2;mm

Length is between 3


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Pressure*control valve 8:$69Pressure*control valve 8:$69

$esponsible for$esponsible for

maintaining themaintaining thepressure in thepressure in therail at arail at aconstant level.constant level.


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$ail*pressure sensor 8$:%9$ail*pressure sensor 8$:%9

/easures the/easures the

pressure in the railpressure in the rail

inputs the informationinputs the information

to the !C"to the !C"RDS shouldRDS should

provideprovideextremelyextremely

preciseprecise

measuredmeasured

values. values.


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Injector Injector Injects exactly the correct amount of fuelInjects exactly the correct amount of fuel

in to the combustion chamber at preciselyin to the combustion chamber at precisely

the right moment in timethe right moment in time


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#he injector is e-uipped with+#he injector is e-uipped with+

3>3 electromagnetic servo valve3>3 electromagnetic servo valve

5o??le5o??le

6alve control chamber 6alve control chamber

$eturn line$eturn line

Injector Injector


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#he essential forces for correct functioning are+#he essential forces for correct functioning are+

5o??le*spring force5o??le*spring force

6alve spring force6alve spring force

!lectromagnet force!lectromagnet force

0orce due to the pressure in the valve*control0orce due to the pressure in the valve*controlchamberchamber

0orce due to the pressure in the no??le needle0orce due to the pressure in the no??le needle

Injector Injector


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!C" with sensors!C" with sensorsCommon $ail is an !:C controlled injectionCommon $ail is an !:C controlled injection

systemsystem

#he !C" controls @ monitors the complete#he !C" controls @ monitors the completeinjection processinjection process

#he sensors delivers all the measured values#he sensors delivers all the measured values

which are re-uired in the processwhich are re-uired in the process


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%ummary

Components of C$0I% are+Components of C$0I% are+

Pre-supply pumpPre-supply pump

High-pressureHigh-pressurepumppump

High-pressureHigh-pressure

accumulator(rail)accumulator(rail) Pressure-controlPressure-control

valve valveRail-pressure sensor Rail-pressure sensor

InjectorsInjectors

!" #ith sensors!" #ith sensors

!$%%$& R'I " I&*!+I$&!$%%$& R'I " I& *!+I$&

S,S+%S,S+%


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!"##"$ %A&L F'(L &$)(!*&"$ ++*(#!"##"$ %A&L F'(L &$)(!*&"$ ++*(#

+'##A% +'##A%

1.The basic functional !ou"s of the co##on !ail a!e $ lo%1.The basic functional !ou"s of the co##on !ail a!e $ lo% & "!essu!e ci!cuit ' hih & "!essu!e ci!cuit ECU an( & "!essu!e ci!cuit ' hih & "!essu!e ci!cuit ECU an(

senso!s.senso!s.

).In the lo% & "!essu!e ci!cuit' the fuel is cleane( b* a filte!).In the lo% & "!essu!e ci!cuit' the fuel is cleane( b* a filte!

an( then t!ans"o!te( to the hih & "!essu!e ci!cuitan( then t!ans"o!te( to the hih & "!essu!e ci!cuit

CA//A5 $)IL 0"!L I5B!C#IA5 %%#!/CA//A5 $)IL 0"!L I5B!C#IA5 %%#!/


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%"//)$%"//)$4.In the high & pressure circuit ( the maximum4.In the high & pressure circuit ( the maximumpressure of 2(4; bar is generated in the high &pressure of 2(4; bar is generated in the high &pressure accumulator 8$ail9.pressure accumulator 8$ail9.

#he pressure is maintained at a constant#he pressure is maintained at a constantlevel ( and the fuel is ta'en from the rail everylevel ( and the fuel is ta'en from the rail everytime an injection ta'es place.time an injection ta'es place.

D.#he !C" controls and monitors the completeD.#he !C" controls and monitors the completeinjection system. "sing the signals from theinjection system. "sing the signals from thesensors( the !C" calculates all the values forsensors( the !C" calculates all the values forthe injection process and triggers thethe injection process and triggers thecomponents in high*pressure circuit 8pressure &components in high*pressure circuit 8pressure &control valve( injectors9.control valve( injectors9.

electronic diesel fuel system ( common rail)

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