Case IH Magnum 310 - Page 65

Engine-Engineandcrankcase
FuelsystemComponents
Pressureregulator
Locatedonthehighpressurepump,itregulatesthe
amountoffuelsuppliedtothehighpressurepumpon
thebasisofsignalsreceivedfromtheEngineControl
Unit(ECU)bymodulatingtheduty-cycle.Thisallows
pressurevariationinsidethecommonrail.
Thepressureregulatorisnormallyopen.Thehighpres-
surepumpisthereforeinmaximumdeliverymodeifno
signalissentbytheECUunit.
TheregulatorisPulseWidthModulated(PWM);itre-
ceives12V(batteryvoltage)fromtheECU.TheECU
completesandvariesthecurrentbycontrollingthe
ground.Theregulatorisnotpolaritysensitive.Resis-
tanceifcheckedshouldbeabout3.2Ω.
RAIL15TR00373AA31
Commonrailreliefvalve
Thecommonrailreliefvalveismountedontheendofthe
commonrail.Itfunctionstoprotectthesystem'scompo-
nentsincaseofafailureoftherailpressuresensoror
thepressureregulatorthatcouldcausethehighpressure
pumptoprovidemorefuelthanthesystemcansafelyhan-
dle.
Thecommonrailreliefvalveisatwostagevalve.When
therailpressurereaches2000bar(29000psi),thevalve
opensandwilldropthecommonrailpressuretoapprox-
imately1000bar(14500psi).Thisallowstheengineto
beoperatedbutatreducedpower.
RAIL15TR00368AA32
Lowpressuregearpump
RAIL15TR00372AA33
Thefuelsupplytransferpumpisagearpumplocatedon
thebackoftheCP3highpressurepump.Thetransfer
pumpisshaftdrivenofftheCP3highpressurepump
shaft.
(A)Supplyfueldrawnfrompre-lter
(B)Supplyfueltonallter
(1)Fuelsupplyreliefvalve5.0bar(72.5psi)
(2)Supplypumpbypassvalve(forbleeding)
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