GMU–GMPROJECTModel-BasedOn-BoardFaultDiagnosisofEmissionControlComponentsinAutomotiveEngines“FaultFinder”1990-19961TheemissioncontrolproblemMainpollutantsinautomotivetailpipeemissions:Hydrocarbons(un-burntfuel)Carbonmonoxide(partiallyburntfuel)Nitrousoxides(compoundsarisingfromhigh-pressurecombustion)Singlecatalyticconverterforthethreepollutants2Catalystefficiencyforthreepollutants3Basicfuel-controlsystem

driverTHROTTLEENGINEFUELINJECTORCONTROLLERPOSITIONSENSOROXYGENSENSORairexhaustfuelfeed-forwardfeedback4

driverExhaustgasrecirculation(EGR)THROTTLEENGINEEGRVALVECONTROLLERMAPSENSORRPMSENSORairexhaust5On-BoardDiagnosis(OBD)–IIRegulation

(Mid-nineties)Anyfaultofanemissioncontrolcomponentcausinganyofthethreemainpollutantstoexceeditslegallimitby50%mustbedetected/diagnosedwithinthreedrivingcycles.Warninglightmustilluminate.Drivingcycle:25minhighway/city6

Carenginemodel

MANIFOLDSUBSYSTEMINERTIALSUBSYTEMAIR-FUELSUBSYSTEM

Thr

EgrFuelLoadMapOxygenRpmThr:throttleEgr:exhaustgasrecirculation

Map:ManifoldabsolutepressureRpm:Revolutionsperminute7Carenginemodel

Carenginemodel

MANIFOLDSUBSYSTEMINERTIALSUBSYTEMAIR-FUELSUBSYSTEM

Thr

EgrFuelLoadMapOxygenRpm8Carenginemodel

Carenginemodel

Carenginemodel

MANIFOLDSUBSYSTEMAIR-FUELSUBSYSTEM

Thr

EgrFuelMapOxygenRpm9Work-plan

Data-collectionfromvehicle (idle,city,highway,hill)Modelidentification (directidentificationofeachequation)AlgorithmdesignCoding(HC11;assemblycode,memory-limitedsystem)Buildingfault-emulators(hardwareonvehicle)Roadtesting(faultfree/faulty)10

11

12

13

14Six-variablesystem

ThrEgrFuelRpmMapVO2

Thr

EgrFuelMapRpmVO2

011111101111110111111011111101111110VO2:Oxygensensorvoltage15

Four-variablesystem

MANIFOLDSUBSYSTEMThrIacEgr

Map

Maf

Thr/Iac

EgrMapMaf

0111101111011110Iac:IdleaircontrolMaf:Massairflow16Thefoursubsystems

THROTTLEBODYINTAKEMANIFOLDThr/Iac

Egr

MafMapMap

Maf17Residualgeneration

MODELEXCEPTIONSMapThr

Iac

EgrMap^rawresidual

ThrRpm

-

+18A“typical”equationMap^(t)=13.72 constant +0.78*Thr(t) +0.049*Iac(t) +0.22*Egr(t)

+0.66*Map(t-1)autoregressiveterm

–0.0085*Thr2(t) –0.001*Iac(t)*Egr(t)lineartermsnonlinearterms19Residualprocessing

LOW-PASSFILTERTHRESHOLDTESTINGUP/DOWNCOUNTERTHRESHOLDTESTINGrawresidualfilteredresidual0/+1/-1count(periodicallyreset)onebitofthefault-code20Residualandcounter–nofault21Residualandcounter–highnoise22Residualandcounter–withfault23Systemreport–nofault24Systemreport–MAFfault25Systemreport–EGRorMAPfault2625-carfleetexperimentFleetof“identical”vehicles(ChevyBlazer)availableatGMCollectdatafrom25vehiclesIdentifymodelsfromcombineddatafrom5vehiclesTestondatafrom25vehiclesResidualmeansandvariancesvary

increasethresholds(sacrificesensitivity)Onlya50%increaseisnecessary27Faultsensitivities

Criticalfaultsizesfordetectionanddiagnosis (fleetexperiment)

Thr

Iac

Egr Map Maf detection 2% 10% 12% 5% 2% diagnosis 6% 20% 17% 7% 8%28ContributorsAtGMU AtGM RonHira Man-FengChang

XiaowenFang MarkCostin

Qiang

Luo

DerongLiu

Moid

Kunwer TomTing

Ramin

Monajemy JohnVanGilder

Zdzislaw

Kowalczuk

JimHeron BillHunter YongLi JasonPeng29Epilogue

May26,2004DETROIT,Michigan-GeneralMotorshonorsitstopinnovatorsof2003atthe28thannual"Boss"KetteringAwardsceremonytoday.The"Boss"KetteringAwardisGM’shighestawardforrecognizingGMtechnicalinventionsandinnovations.30FaultFinder:Model-BasedApproachforAdvancedEngineDiagnostics

Thismodel-basedapproachforadvancedengine

diagnostics…requiresnoadditionalsensorsorotherhardware,reducesfalse-alarmrates,improvesvehiclerepairratesanddealershipeffectiveness.31

Thisinnovationhasbeen

implementedinthe

2004ChevroletMalibu

featuringECOTEC2.2-LITER4-cylinderengines;

Cadillacs

featuringtheNorthstar

4.6-literV-8engines;and

ChevroletColoradoandGMCCanyonmid-sizetrucks.TheFaultFinderteami