common rail direct injection

8/18/2019 Common Rail Direct Injection

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CommoDirect In

CR


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What is CRDI ?

CRDI stands for Common Rail Direct Injection.

Direct injection of the fuel into the cylinders of anvia a single, common line, called the common railis connected to all the fuel injectors.

Instead of providing separate piston pumps for fusupply, the common rail alone supplies high pressto each cylinder.


3/18

The Technology

Whereas ordinary diesel direct fuelinjection systems have tpressure anew for each and every injection cycle, CRDI engimaintain constant pressure regardless of the injection se"ue

This pressure then remains permanently availa!le throughouline.

The electronic control unit #$C%& modi'es injection pressureas needed, !ased on data o!tained from sensors on the camcran(shafts. ie compression and injection occur independenother.

This techni"ue allows fuel to !e injected as needed, saving flowering emissions.


4/18

)RI*CI)+$ - CRDi I* DI$$*/I*$

• is named as /DI# /asoline Direct Injection&

• Introduced to remove the draw!ac(s of car!ureted and0)-I systems

• 0ain advantage is that even petrol engines can !e run unvery lean mi1ture ratio of 2345.


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Figure showing that by introduction of GDI in petroengines A lean mixture of A\F ratio of !"# can be bsuccessfully


6/18

$ayout of a typical CRDIsystem


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Di%erences betweenDI and CRD

• Constant pressure regardless of the injection se"ue

• -uel is supplied directly to a common rail from whis injected directly onto the cylinder head

• 6igh )ressure of a!out #5733 !ar& , Improvedpulveri8ation

• $lectronic engine management system continually athe pea( fuel pressure according to engine speed athrottle position

• Compression and injection occur independently of other


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Circuit Diagram


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$lectronic Control %n

• $C% monitors $ngine varia!les such as

• Temperature• inta(e pressure• R)0• air mass inta(e• demand for power #from accelerator&

• provides real time control• modi'es injection pressure precisely as nee

!ased on data o!tained from cam and cran


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$lectronic -uelInjector

9 $lectromagnet moplunger openin

solenoid valve9 Injector pulse width

controlled !y $C%


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C6:R:CT$RITIC

• piral shaped Inta(e port for optimum swirl of aentering cylinder ; spiral port induces optimumin the inta(e air leading to more e


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• :ir=ow meter located in front of the tur!ocharger>s

compressor permitting an e1act analysis of the airmthat is !eing ta(en in.

• :ir mass alters depending on temperature or atmospressure.

• The microcomputer that controls engine timing receprecise data.

• It is thus a!le to regulate e1haustgas recycling accoengine load and speed in the interest of lowering nit

o1ide and particle emissions.

)recise :ir -low 0etering


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0ultiple )ilot :nd )ost Injectio

9+eading to smoother compression and e1pansionreducing noise levels

90ore ef'cient com!ustion and !urning up of fueto "uieter engine cycles

9Reduces un!urnt 6C , *1 and C and particlese1haust


14/18

CRDI -uture Trends

9 %ltrahigh pressure commonrail injection #533 !ar&generating ideal swirl in the com!ustion cham!er alloair@fuel mi1ture to form a perfect vertical vorte1 unicom!ustion and greatly reduced *1 emissions

9 CRDi and )article -ilter To reduce particle emissionse1haust

9 CRDi and closedloop control injection %sing ion senprovide realtime com!ustion data for each cylinder stemperature and pressure.


15/18

&AR'IC$(FI$'(R

• Porous s

carbide

• Decreas

emission

• Trapped

burnt up

water


16/18

:DA:*T:/$ -CRDI

• Reduced noise and vi!ration

• Reduced smo(e , particulates and e1haust• Increased fuel economy

• 6igher power output even at lower rpm

DI:DA:*T:/$9 Increased Cost due to high pressure pump and

electronic control unit

9 Technology cannot !e employed in present eng


17/18

6yundai :ccentCRDi

Pioneering new generation

CRDi engines in India•3 Cylinder 1.5 litre and 4 cylinder 2 litre

engines

•81 bhp and 187 NM max tor!e at 27"" rpm #

max 4""" rpm

•5 speed gear box # " $ 1"" in 13 sec # max speed

17" %m&hr

• 2'.2 %mpl in high(ay # 12 %mpl to(n riding


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C)*C$+,I)*9 Cuts fuel consumption by -!.

9 Doubles tor/ue at low engine speeds

9 Increases power by -.09 It also brings a signi1cant reduction in the noise

2ibrations of con2entional diesel engines0

9 In emission3 greenhouse gases 4C)-5 is reduced bconstant le2el of *)x3 carbon monoxide 4C)5 emi

reduced by 6!.3 unburnt hydrocarbons 47C5 by

particle emissions by 8!.0

9 CRDI principle not only lowers fuel consumption aemissions possible9 it also o%ers impro2ed comfo

/uieter than modern pre:combustion engines0 Co

engines are thus clearly superior to ordinary mot

common rail direct injection

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