7大型养路机械常见故障处理7.4常见故障诊断及维修2Common-fault-treatment-of-large-scale-maintenance-machinery-7

RAILWAYSECTORDiagnosisandmaintenanceofcommonfaultsCONTENTSEnginefailure-temperaturecontrolvalvefailureEnginefailure-preheatingsolenoidvalveisbrokenEnginefailure-loosevalveclearancetighteningnutcausestheenginetoworkabnormallyEnginefailure-temperaturecontrolvalvefailure1.FailurephenomenonTheengineoiltemperatureishigh.Enginefailure-temperaturecontrolvalvefailure2.FailureanalysisThemainreasonsforhighengineoiltemperatureareasfollows:(1)Coolingfanfailureorfandrivegearboxfailure;(2)Theoilradiatorisdirty;(3)Thesealsinvariouspartsofthemachinebodyaredamagedorthewinddeflectorfallsoff;Enginefailure-temperaturecontrolvalvefailure(4)Thecoolingcirculationoilpathisbypassed;fromtheexternalinspection,thepossibilityoftheoilradiatorbeingdirtyandthesealsofthemachinebodydamagedhasbeenpreliminarilyruledout.Furtherinspectionshavenotfoundanyproblemswiththefantransmissiongearboxandthetransmissioncoupling.Thefanbladesrotateflexibly,sothepossibilityofmechanicalfailureisruledout.Theproblemshouldbethatthefailureofthetemperaturecontrolvalvecausesthecoolingcirculationoilpathtobypass,andultimatelytheheatdissipationeffectisnotgood.Enginefailure-temperaturecontrolvalvefailureDuringmaintenance,workersfoundthatthetemperaturecontrolvalveoftheleftaccessorybracketwasblockedbyoilleakage,sotheyremovedtheinstallationandadjustmentcopperpadandtighteneditwitharawmaterialtape,whichcauseddeformationofthetemperaturecontrolvalveshellandcausedthetemperaturecontrolvalvebodytobecomestuck.ThetemperaturecontrolvalvecannotfreelyexpandandcontractwithtemperaturechangesEnginefailure-temperaturecontrolvalvefailureInordertoprotectthetemperaturecontrolvalvefromheatlosswhentheengineisjuststarted,thevalvebodyshieldstheoilpassageandbypassesmostoftheoilleadingtotheoilradiator.Becausethelefttemperaturecontrolvalveisstuckatthisposition,mostoftheoilcannotbeused.Enteringtheradiatorforcooling,onlytherightradiatorworks,causingtheengineoiltemperaturetobehigh.Enginefailure-temperaturecontrolvalvefailure4.TroubleshootingThefaultdisappearedafterreplacingthelefttemperaturecontrolvalve.Summary:Theenginedesignisrelativelycompact.Eachinstallationplugandprocessplug,includingadjustmentpads,hasitspurpose.Theoperatorcannotdisassembleandassemblevariousparts(suchasmainoilpassagepressure)withoutfullyunderstandingtheenginestructureandbasicprinciples.Thesafetyunloadingvalveisblocked)toavoidunnecessarylosses.Enginefailure-temperaturecontrolvalvefailureEnginefailure-preheatsolenoidvalvedamaged1.FailurephenomenonTheenginewasmaintainedthepreviousdayandworkednormally,buttheenginewasstartedseveraltimesthenextdaywithoutsuccess.Initialinspectionofthecircuit,oilcircuit,andgascircuitshowednoabnormalities.Enginefailure-preheatsolenoidvalvedamaged2.FailureanalysisAftercheckingthatthebatteryisnormal,thestartingmotorisnormal,theshutdownsolenoidvalveisingoodtechnicalcondition,andthecircuitfailureiseliminated;thehandoilpumpispumpingoil,andthereisnoairbubbleintheoilcircuit,theoilcircuitisunobstructed,andtheoilcircuitfailureiseliminated;checktheairfilterisgood,buttheintakepipeThereareslightoilstainsonthehose.Afterdisassembly,itisfoundthatthereisalargeamountofdieselintheintakepipe,andthenitisjudgedthatthedieselcomesfromthepreheatingsolenoidvalve.Enginefailure-preheatsolenoidvalvedamaged3.ThecauseofthefailureThepreheatingsolenoidvalveisinpoortechnicalconditionandstuckintheopenposition.Aftertheshutdown,theresidualpressureofthehigh-pressureoilpumpandthelow-pressurefueldeliverypumpwillpassthedieselthroughthepreheatingsolenoidvalveandthenentertheintakepipethroughthepreheatingsparkplug,causingthecylindertobestuffyandunabletostarttheengine.Enginefailure-preheatsolenoidvalvedamaged4.TroubleshootingReplacethepreheatsolenoidvalve,disassemblethestopsolenoidvalveconnector,usethestartermotortodrivethepistontomove,andrestorethestopsolenoidvalveconnectoraftertheoilisthrown,andreturntonormal.Enginefailure-preheatsolenoidvalvedamaged4.TroubleshootingSummary:Whentheengineislow-speedandlight-loaded,itisnecessarytoobservetheenginesmokeexhaust.Ifthepre-heatingsolenoidvalveisfaultyandthereisnooil,theglowplugwillbeburned.Whentheopenpositionisstuck,theexhaustwillbeaccompaniedbymildblacksmoke.Removethepreheatingsparkplugandtheoilinletpipejoint.Thepreheatingsolenoidvalveinnormalworkingconditionwillsupplyoilwithinafewsecondswhenitisstarted,andthenstoptheoilsupply.Enginefailure-preheatsolenoidvalvedamagedEnginefailure-thevalveclearanceistightandthefixednutisloose,causingtheenginetoworkabnormally1.FailurephenomenonTheengineburnspoorlywhentheengineisworking,withblacksmokefromonesideoftheexhaustpipeandlightbluesmokefromtheotherside,andtheengineoillevelrisesrapidly.Enginefailure-thevalveclearanceistightandthefixednutisloose,causingtheenginetoworkabnormally2.FailureanalysisAccordingtotherapidriseoftheengineoillevel,itisjudgedthatthedieselinacertaincylinderisnotfullyburnedandenterstheoilpan.Aftermonitoringtheengine,itisfoundthatthereisanabnormalsoundofviolentmechanicalknockingontherightside;afterstoppingtheinspection,itisfoundthatthevalveclearanceadjustmentlocknutonthe11thcylinderintakevalverockerarmhasbeencompletelyloosenedsothattheintakevalvecannotbeopened.Enginefailure-thevalveclearanceistightandthefixednutisloose,causingtheenginetoworkabnormally3.ThecauseofthefailureAftertheenginemaintenancepersonneladjustedtheenginevalveclearance,theydidnotapplysufficientpre-tighteningforcetothe11-cylindervalveclearanceadjustmenttighteningnutaccordingtotheregulations,sothatthetighteningnutwasloosenedduringuse,andeventuallyalltheintakevalvesofthecylindercouldnotbeopened.Thefuelcannotburnnormally.Enginefailure-thevalveclearanceistightandthefixednutisloose,causingtheenginetoworkabnormally3.ThecauseofthefailurePartofthefueldirectlyenterstheoilpanalongthecylinderwallpistonringgap,causingtheengineoilleveltorisebeyondtheregulationsandcausingtheenginetoburntheoiltoproducebluesmoke;theotherpartofthefuelisbroughtintotheexhaustpipeandperformspoorlyunderthehightemperatureoftheexhaustpipe."Post-combustion"causestheenginetoemitblacksmoke.Enginefailure-thevalveclearanceistightandthefixednutisloose,causingtheenginetoworkabnormally4.TroubleshootingDuetothefailuretobediscoveredintime,thedieselwasmixedintotheengineoillubricationsystemandaffectedthelubricationofthemainbearingbushes.Inordertoavoidpotentialequipmentsafetyhazards,theenginewasoverhauledina