远程诊断和汽车维修系统概述.docx

远程诊断和汽车维修系统概述.docx

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远程诊断和汽车维修系统概述

远程诊断和汽车维修系统概述

英文资料OverviewofRemoteDiagnosisandMaintenanceforAutomotiveSystems1.INTRODUCTION1.1.CurrentvehiclediagnosisAllcarsandlighttrucksbuiltandsoldintheUnitedStatesafterJanuary1,1996arerequiredtobeequippedwithOn-BoardDiagnosticsII（OBD-II）.WhiletheprimaryimpetusforOBD-IIwasdiagnosticsforemissionsystems,therangeofvehiclesub-systemsaddressedbythisstandardisquitebroad.TheOBD-IIDiagnosticTroubleCodes（DTCs）aremadeupof5digits[1].Whilethesecodesareusefultoidentifyfaultysubsystems,theyaretypicallynotsufficienttoidentifyspecificfaultycomponents.ThetroublecodesaretypicallyaccessedthroughascantoolthatispluggedintoaspecialOBD-IIvehicleconnector.Thisconnectorislocatedinthepassengercompartmentandcanbeaccessedfromthedriver’sseat.Hand-heldscantoolsareusuallylimitedtovehiclesfromoneormoremanufacturer.Ingeneral,Chryslerproducts,allEuropeanandmostAsianimportsusetheISO9141standardforin-vehicleOBD-IIcommunications.GMcarsandlighttrucksuseSAEJ1850VPWM（VariablePulseWidthModulation）,andFordsuseSAEJ1850PWM（PulseWidthModulation）1.2.ProblemswithcurrentvehiclediagnosisApproachesFromabovedescriptionwecansee,thereareseveralproblemsinthecurrentapproachtovehiclediagnosis.1.Thediagnosisisnotstandardizedamongvehiclemanufacturers.Thisleadstohighercostswhenvehiclesfromdifferentmanufacturersaretobediagnosedbyagivenfacility.2.Thediagnosisrequiresdrivingtoarepairfacility.Thisisaninconveniencetothedriverandasourceofuncertaintyinschedulingvehiclediagnosisandrepair.Thedrivermaybetoldtoleavethevehicleforthedaywhentheproblemcanbesolvedinanhour.3.Acompletediagnosismayneedspecialequipmentandtrainedtechnicianhelp.Thiscanmakethediagnosisveryexpensive.4.TheDTCinformationistypicallynotaccurateenoughtopinpointthesourceoftheproblem.Bettervehiclediagnosticalgorithmsandstrategiescouldreducethetimeneededtodiagnoseproblems.5.Withtheincreasedsophisticationofelectroniccontrolsystemsinvehicles,thereisaconcomitantincreaseinthedifficultyofidentifyingcomponentmalfunctions.Onesymptomofthisisthediagnosisofreplacedpartsasnotroublefound.1.3.CurrentvehiclemaintenancestrategiesCurrentvehiclemaintenancestrategiesgenerallyconsistofcorrectiveandpreventivemaintenanceapproachesoracombinationofthese.Inthecorrectivemaintenanceapproach,thevehicleismaintainedonanas-neededbasis,i.e.afterafaulthasoccurred.Thiscanbeariskyapproachasitmay,overtime,leadtounexpectedbreakdownsandmorecostlyrepairsduetohigherlevelsofdamage.Attheotherextreme,preventivemaintenancereliesonreplacingcomponentsandfluidsbasedonaconservativescheduletopreventpossiblefailures.Althoughpreventivemaintenanceprogramsmayincreasesystemavailability,theyleadtoincreasedcostofvehicleownershipduetothereplacementofpartsandfluidswellbeforetheendoftheirusefullife.Ingeneral,preventivemaintenanceschedulesaretypicallytimeormileage-basedstrategyanddonotaccountforactualvehicleoperatingconditionsorsubsystemhealth.Asaneverydayexample,drivershavelittleideaofhowtotradeoffthemanyfactorsinoillifeandareadmonishedbytheoil-changeindustrytochangetheiroilevery3,000miles;manyvehiclemanufacturers,however,recommendmuchlongerintervalsfornormaldrivingconditions.Studieshaverevealedthatmosttheequipmentfailuresarenotrelatedtothenumberofhoursofoperation.Manydriversuseamixofcorrectiveandpreventativestrategies,dependingonthesubsysteminvolved.1.4.ProblemswithcurrentvehiclemaintenancepracticesCorrectiveandpreventativevehiclemaintenancepracticesaresub-optimalstrategiesintermsofthecostofvehicleownershipanddriverconvenience.Neitherstrategyaccountsforactualvehicledrivingconditionsorcurrentcomponent/fluidhealth.Inaddition,vehicleoperatorsoftendonotreadthemaintenanceschedulesintheirownersmanualor,iftheydo,havedifficultyindecidingbetweenmoderateorsevereoperatingconditions.AccordingtoaSeptember15,2003reportpublishedbytheCommissionoftheEuropeanCommunity,repairandmaintenanceaccountsfor40%ofthetotallifetimecostsofvehicleownership[5].Thus,theaffordabilityofvehiclesdependsnotonlyoninitialvehiclecostbutthecostofrepairandmaintenance.2.SIGNIFICANCEOFREMOTEDIAGNOSISMAINTENANCERecentadvancesinremotecommunications,humanmachineinterfaces,model-baseddiagnostics,electronicsandembeddedsystemtechnologiesareleadingtoadramaticshiftinthewaythevehiclesisdiagnosedandmaintained.Theseadvancesequiptheautomobileswiththecapabilitysharein-vehiclesensoranddiagnosticinformationwithremotecomputers,enablingvehiclediagnosisandmaintenancebeperformedremotelywhilethevehicleisbeingdriven.Inaddition,vehicleparametersmcanbemonitoredwhilethevehicleisbeingdriventodeterminewhenmaintenanceisnecessary.ThesecapabilitiescoupledwithincreasedconsumerinterestarethereasonswhyvehicleRDMisdrawingincreasingattentionintheautomotiveindustry.2.1.RemoteDiagnosisMaintenanceBackgroundRDMisamultidisciplinarysubjectthatembodiesmanyvehiclesubsystemsandtheirassociateddiagnosticandmaintenanceneeds,aremoteanalysiscenter,andwirelesscommunication.Anumberofrecentpatentsandarticleshaveaddressedavarietyofapplication-specificissuesrelatedtoRDM.Examplesincludeavehiclecommunicationsystemtoestablishatwo-waycommunicationslinkbetweenthevehicleandaremotecomputer,andanautomatedvoiceresponsesystemtoprovideamethodforremotelydiagnosingavehicle.AlsoNASAhasdevelopedaremotediagnosisservertomonitorthehealthofthespaceshuttle.Severalcompanies,includingGMsOnStar;NEXIQTechnologiesInc.,ATXTechnologiesInc.,Toyota,VetronixInc.,JentroAG,BMW,Volkswagen,IBW,andDearbornGroup,eitheralreadyhaveorareactivelydevelopingRDMapplications.GMsOnStarsystemhasevolvedfrombeinganoptiononCadillacstostandardequipmentonnearlyallGMvehicles.OnStarintegratescellphoneservice,roadsideassistance,emergencyservice,andsimpleremotediagnosticsbasedonDiagnosticTroubleCodes（DTCs）.GMprojectsthatOnStarsystemwillbeinstalledin4millionvehiclesby2005.Afewothercarmanufacturers,includingToyota,VolkswagenandBMW,areworkingonsimilartelematicssystemsandarerollingoutmodelswithintegratedearly-generationremotediagnosticstechnologyaswell.2.2AdvantagesofRDMAsdescribedinthescenariosatthebeginningofthisreport,RDMshouldhavetheabilitytounobtrusivelydiagnosevehiclehealthwithouttheneedtodrivetoaspecialrepairfacility.RDMsystemscanexamineautomotivefaultcodesandinternalsensorvaluesnomatterifthecarisrunningontheroadorparkedinthegarage,withouttheinvolvementofavehicleservicetechnician.ThesereadingscanbewirelesslytransmittedtoaremoteRDMserver,wherevehicleinformation,suchasrecordsofvehicleserviceandpreviousrepairarestored.ARDMservercanusepowerfulprocessingcapabilitytoassessvehiclehealthandremindownersifmaintenanceisrecommended.Ifaproblemisdetected,thedrivercanbewarnedofthemalfunction,cangethelpfromanadvisortoassesstheseverityofproblemandtoschedulemaintenanceorrepair.Ifneeded,advanceddiagnosticalgorithmscouldberemotelydownloadedtothevehicleforperformingcomplexdiagnostictasks,andrecoveryandrescueservicescouldbeactivatedtodealwithfaultyconditionsand,possibly,savelives.Remotemaintenanceprogramcanaidinreducingoperatingcostsandincreasesafetyby,forexample,earlydetectionoflowtirepressure,determiningwhenanoilchangeisneeded,orwhenbrakeliningsareinneedofreplacement.Earlywarningsofproblemsmaypreventsomeon-the-roadbreakdownsand,insomecases,mayavertaccidents.RDMshouldgivedriverspeaceofmindbytakingmuchoftheambiguityoutofthecurrentapproachestodiagnosticsandmaintenance.VehiclemanufacturerscanalsouseRDMasanearlywarningsystemtodetectvehiclewarrantyproblemsearlyinthemodelyear.TheauthorsbelievethatasthenumberofautomobilesequippedwithRDMincreases,consumerswillincreasinglyrecognizethelong-termcost-to-benefitratioofthesesystems.2.3PotentialConsumerInterestinRDMAutomotivetelematicsisgrowingrapidlyandRDMisgenerallyregardedasoneofthemostimportanttelematicsservices.AccordingtoarecentsurveybyInfoMove,aSeattleproviderofpersonalized,locationbasedapplicationsandwirelessservicesforautomobiles,73percentofconsumerswouldlikeautomakersanddealerstobeabletodiagnosecarproblemsremotely.ProjectionsbyAlliedBusinessIntelligence,anOysterBay,NY-basedresearchfirm,indicatethattelematicsproductsandservicesareexpectedtogrowfromanaggregate$2.2billionglobalmarketin2019tomorethan$12.3billionby2007.AgoodindicationofthestrengthofconsumerinterestinautomotivetelematicsservicesisthegrowthofOnStarsubscribers,andtheemulationofOnStartypeservicesbyotherOEMs.2.4RDMforX-By-WiresystemsX-By-Wiresystemswereintroducedinaircraftwelloveradecadeago,firstinmilitaryandthenincommercialaircraft.Thesesystemsreplacehydraulicandmechanicalsystemswithelectronicallycontrolledsystems.InatrueX-By-Wiresystem,thereisnohydraulicbackuptotheelectronicsystem.X-By-Wiresystemsaregainingmomentumintheautomotiveenvironmentforste