汽车故障诊断与排除的基本方法.docx

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汽车故障诊断与排除的基本方法.docx

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汽车故障诊断与排除的基本方法.docx

汽车故障诊断与排除的基本方法

Coretip:

thebasicmethodofautomobilefaultdiagnosisandtroubleshootingisthebasisoftroubleshootingandtheeffectivemeanstoimprovetheefficiencyofvehiclemaintenance.Inordertodiagnosefaultsquicklyandaccurately,itisnecessarytounderstandthebasicthinkingandmethodsofdiagnosingfaults,andtomasterthebasicrequirementsandmethodsfortroubleshooting.First,thebasicthinkingandmethodsoffaultdiagnosis,thediversityofvehiclefaultphenomenaandthecomplexityofthecause,leadtothediversityanduncertaintyofthethinkingandmethodsoffaultdiagnosis...

Thebasicmethodofautomobilefaultdiagnosisandtroubleshooting

Thecorrectdiagnosisofthefaultlocationisthebasisoftroubleshooting,butalsoaneffectivemeanstoimprovetheefficiencyofvehiclemaintenance.Inordertodiagnosefaultsquicklyandaccurately,itisnecessarytounderstandthebasicthinkingandmethodsofdiagnosingfaults,andtomasterthebasicrequirementsandmethodsfortroubleshooting.

I.BasicThinkingandmethodofdiagnosingfaults

Thecomplexityanddiversityofautomobilefaultphenomenonreason,causedthediversityofideasandmethodsoffaultdiagnosisanduncertainty,butonthewhole,thebasicideasandmethodsshouldbebasedonthefirstmechanicalelectronics,firstspecial,easytodifficult,simpletocomplexprimarydiagnosis.

1,thebasicprocessofdiagnosingfaults

Thebasicprocessofdiagnosingautomobilefaultsusuallyincludesthefollowingsteps:

inquiringthesituation,reproducingthefaultphenomenon,determiningthefaultcharacteristics,analyzingthecauseofthetrouble,drawinguptheinspectionscopeandfindingthefaultpoint.

Askaboutthesituation.Mainlytothedrivertounderstandthevehiclebeforethefailureofsomebasicinformation,suchasvehiclemileage,vehiclemaintenanceandrepair,theuseofvehiclesatordinarytimes,beforethefailureofthespecialphenomenon.

Reproducethefaultphenomenon.Bymeansofacertainmethodandtechnicalmeans,thephenomenonoffailurewillbemanifested,suchasin-situlaunch,roadtest,etc..Forcontinuousreproductionoffault,faultphenomenaaregenerallyeasier;butsomeoftheintermittentfault,becausethefaultoccursonlyinaparticularenvironment,sotheneedtoreproducebymeansoffaultsimulationenvironment,suchasthroughvibration,heating,water,orload（load）etc..

Determinefaultcharacteristics.Thefaultphenomenoncausedbyafaultisusuallycharacterizedbyitsspecificfault,thatis,faultcharacteristics,anditisveryimportanttofindoutthefaultcharacteristicsandreducethediagnosticrangeanddiagnosethefaultquickly.Forexample,aunitofSX2190commercialvehicles,intheexecutionofthetask,suddenlyappearedvehicleunderpowered,theenginerunningweak,untilslowflameout.Drivingonthephonereflects:

hitthestarter,nocar,usingelectricfuelpumpexhaust,foundalargenumberofbubblesdischarged,airdischargedafterthesmoothstart,butafteraperiodofmileage,thefaultoccurredagain.Tofurtherunderstandthesituationthatthiscarsincetwolevelmaintenanceaftertravelingaround5000km,whichfoundnosuchfault,buttherecentdifficultstarting,generallyaccordingtotheelectricfuelpump,andtheelectricfuelpumpandfoundnoleakagephenomenon.Thedieselfilterwascleanedtwodaysbeforethefailure.Fromthebasicinformationreflectedbythedriverabove,itcanbedeterminedthatthecarhasmanyfaultphenomena,suchasdifficultstarting,enginerunning,vehiclepowershortageandengineflameout,

Butwhatfaultcanrepresentfaultcharacteristics?

Itisclearthattheengineitselfisthemostrepresentativeofthebreakdowncharacteristicsofthecar.

Analyzethecauseofthetrouble.Accordingtothespecificstructureandfaultcharacteristicsofthecar,thecauseofthetroubleisanalyzed.Intheexampleabovecausestheenginetostall.

A.tankwithoutoil.

B,thediesellineisnotsealedandenterstheair.

C.dieselfilteranddieselpipeblocked.

Coretip:

D.thereiswaterinthefuel.

E.oilpumpdoesnotwork.

F.injectionpumpconnectionplatefixedboltsloose.

G.fuelinjectionpumphandlerodfalloff.

H.theoiloutletvalveandneedlevalveofthesamecylinderarenotsealed.

Sincethecarfaultisslowflameout,soF.Gcanbeexcluded（F.Gcausedbysuddenflameout）;thecarenginepowerisnotdecreased,Dcanbeexcluded;thecarcanstillworkforaperiodoftime,ecanberuledout;accordingtotheelectricfuelpumpcanbeinacar,andthefailureoccurredtwodaysbeforethefiltercleaning.AandCcanberuledout;accordingtotheelectricfuelpumpnotfoundleakingposition,Bcanberuledout:

sotherestofthehwithacylindervalveandneedlevalveandvicevicesealshouldbethecauseofthefailure.

Formulationofinspectionscope.Determinethescope,procedureandmethodoftheinspectioninaccordancewiththeconclusionsofthefailureanalysis.

Tofindthepointoffailure.Accordingtothescopeofinspection,themethodofsubsection,fixed-pointorpointbypointinspectionisadopted.Atthetimeofinspection,thetechnicalstandardsofthecheckedpartsshouldbewellknown,andatthesametime,theinspectionshouldbeavoided.

2analyzethemainpointsofthetrouble

Analysisoffaultreasoningisessentiallyaprocessofthinking,theprocessforthelengthoftime,thereasoningiscorrectornot,isaffectedbymanyfactors,suchastheaccumulationofexperienceandknowledge,usingthestructureofautomobilediagnosticinstrumentbyskilleddegreeandqualityofthinkingclarity,flexibility,sensitivityandstability,psychologythequalityofhealth,willbedifferentdegreesdirectlyorindirectlyinfluencethespeedandqualityofreasoning.

Intheprocessoffaultanalysis,experienceisaveryimportantfactor,especiallyforthosewhohavebeenengagedinsinglevehicletypeandfixedsystemmaintenanceforalongtime.Thespeedandaccuracyofcommonfaultanalysisareveryhigh.Thereason,ontheonehand,isduetothelongexperienceintheaccumulationofdirectexperienceisveryrich,ontheotherhand,italsobenefitsfromitscontinuoussummaryandimprovement.Inadditiontodirectexperience,throughcasestudyanddissection,itisaneffectivewaytoobtainmaintenanceexperience.Thisiscalledindirectexperience,andindirectexperienceisofgreathelptoimprovethequalityoffaultanalysis.Whetheritisdirectexperienceorindirectexperience,ingeneral,itcanplayapositiveroleinthefaultanalysisprocess,

Thatis,experienceguidesthinkingquicklyandaccuratelytofindfaultpoints.Forexample,iffaultcodedisplayengine,shouldfirstcheckthefaultcodedisplaycontent,thisexperiencemaymakeyouwinallthetime,intheworktostrengthentheexperienceifthingsgoonlikethis,inyourmind,andgraduallysolidified,becomeamindset.However,ifonedayyoufindthatthisexperienceisnotworking,andwhenyouhavecheckedthecircuitaccordingtotheexperience,andreplacedtheelectricalcomponents,thefaultstillexists,thatis,experiencehasplayedamisleadingrole.Instead,itbecomesabarriertocorrectthinking.Sotheexperienceisvaluable,butisnotlimitedtospecificconditionsmethod.

Itishardtoimagineadoctorwhoknowslittleaboutthestructureofthehumanbodyandcanquicklyandaccuratelydiagnosethecauseofthedisease.Also,thebasicknowledgeofautomobilestructureknowledgeisalsoessentialvehiclemaintenance,inadditiontothe"fivebase",namelythebasicstructure,basicfunctionandcompositionofthebasiccontrolrelation,basicprinciple,basicperformanceparameters,thestructuralfeaturesofdifferenttypesofcarshouldalsobeunderstoodthatthespecificstructureofthefaultofthevehicletobeaware,otherwisemostofourpreparationbecameafalse,YongZhishui.Itshouldbeemphasizedthat,withtheincreasingapplicationofelectronictechnologyinthecarmorewidely,theelectroniccontrolsystemsoftwareupgradefaster,moreandmorewiderangeofcontrol,controlprecisionismoreandmorehigh,sothetaskisveryimportanttostudythecontrolsystemsoftware,hardwareandsoftwaretomatchknowledgethehardwarestructureofthecorrespondingsoftwareversionsarenotthesame.

Intheprocessoffaultanalysis,itisnecessarytousediagnosticinstrumentsandequipmentparametersorperformancetestingnecessary,commonlyusedinstrumentsandequipmentinadditiontobeabletouse,weshouldpayattentiontothedetectionaccuracyofcalibrationinstrument,theequipmentitself,topreventtheemergenceoflargedetectionerror,whichbringsdifficultiestofaultanalysis.

Coretip:

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