汽車實用英語第二版高職PPT完整全套教學課件

汽車實用英語全套PPT課件unit1AutomotiveMaintenance.pptUnit2EngineMechanicalSystemService.pptunit3EngineElectronicControSystemServicel.pptunti4ElectricSystemService.pptUnit5PowerTransmissionSystem.pptunti6ChassisService.pptunit7RepairofVehicleBody.pptUnit1AutomotiveMaintenanceUponcompletionofthisunit,youshouldbeableto:OverallObjectives?Learnkeytermsaboutautomotivemaintenanceinthisunit.?Understandthebasicproceduresofautomotivemaintenance.?Usemaintenancemanualtodealwiththepracticalproblems.Task2.1EngineOilandOilFilterChange-發(fā)動機機油和機油濾清器更換Task2.2CheckingDriveBelt-檢查傳動帶Task2.3CheckingCoolingSystem-檢查冷卻系統(tǒng)Task2.4ReplacingSparkPlugs-更換火花塞Task2.5ReplacingAirCleanerElement–更換空氣濾清器芯TasksIntroductionAutomotivemaintenance（維護，保養(yǎng)）describestheactofinspectingortestingtheconditionofcarsubsystemsandservicingorreplacingpartsandfluids.Regularmaintenanceiscriticaltoensurethesafety,reliability（可靠性）,drivability,comfortandlongevityofanautomotive.Thefollowingtasks(e.g.oilandfilterchange,checkingdrivebelt,replacingsparkplugs,etc.)aretheimportantitemsinautomaintenancetoavoidmajordamageorforsafetyreasons.TaskDescriptionTask2.1EngineOilandOilFilterChangeLearningPreparationmaintenance維護，保養(yǎng)oil機油oilfilter機油濾清器

oilpan油底殼jackup用千斤頂頂起remove開除；

去除；

拿下undo松開，解開；取消drainplug放油螺塞sealingring密封圈tighteningtorque擰緊力矩Keyterms:Step1Amaintenancecaseisprovided;Step2Learntheprocessofchangingoilandoilfilterviaamaintenancemanual;Step3Requirestudentstograspthekeytermsinthistask;Step4Trytodescribetheprocessofoilandoilfilterchange;Step5Studentsreadrelativematerial;Step6AssessmentPlanandImplement()1.Engineoilshouldbedrawnfromtheoilpan.()2.Thevehiclecanbejackedupatanypoint.()3.Theoildrainplugsshouldbecleanedbeforeitisinstalledtothevehicle.()4.Theoilfiltershouldbeunscrewedbyaspecialtool.()5.Theoilfilterhousingshouldberemovedhorizontallydownwards.AssessmentandFeedbackTrueorFalse()6.TheoilfilterhousingmustbeprotectedcarefullyduringO-ringbeingleveredoff.()7.Theoilfilterhousingshouldbetightenedto19Nm.()8.TheO-ringcanbereused.()9.Thecarmustbejackedupbeforeyouchangetheoil.()10.Thewasteoilcanbedisposedasyoulike.Theenginelubricationsystem（潤滑系統(tǒng)）servestwopurposes:itreducesmetal-to-metalfrictionandwearbetweenrotatingandslidingparts,anditcarriesexcessheatawayfromtheengine.Amongtheimportantsurfacesrequiringlubricationarethecrankshaft（曲軸）journalbearings,connectingrodbearings,pistonpins,cylinderwalls,pistonskirtsandrings,camshaft（凸輪軸）bearingsandvalvemechanism.2.1.1LubricationSystemFig.2.1.1LubricationSystem1-oilgallery;2-oilpump;3-oilpan;4-oilfilter;5-mainoilgalleryAnoilsupplyof4to5quarts(orliters),dependingonenginesizeanddesign,ismaintainedinthecrankcase（曲軸箱）.Ascreened,floatingoilintakeisprovidedbyalubricating-oilpump.Locatedinthedeepestpartofthecrankcase,theintakerisesandfallswiththeoillevel.Oilispickedupbythecirculatingpumpanddeliveredatapressureofapproximately40poundspersquareinch(3kg/cm2)toamaingallerythatrunsthelengthofthecylinderblock.Branchpassagesthenconducttheoiltothevalvemechanism,camshaftbearings,andcrankshaftmainbearings.Fromthemain-bearingjournalsitflowsthroughthedrilledcrankshafttotheconnecting-rodbearings,passingupthroughdrilledholesintheI-beamconnectingrodstothewrist-pinsandpistonbossestowhichtheyareattached.Cylinderwalls（氣缸壁）andpistonskirtsarelubricatedbyoilthrownfromrotatingparts;excessoilisscrapedfromthecylinderwallsbytheoil-controlringsanddrainedbackdownintothecrankcase.Agaugeorsignallightontheinstrumentpanelindicatesthestateoftheoilpressure.Theoillevelinthecrankcaseismeasuredeitherbyagraduated“stick”typeofgaugeorbyadirect-readinggaugeontheinstrumentpanel.Thevarioustypesofmotoroilonthemarketaredesignedfordifferentpurposes.Tochoosethepropertypeofoilforyourvehicle,youneedtounderstandthesignificanceoftheoiladditives（添加劑）,viscosityratings（粘度比）,andclassificationcodes.2.1.2HowtoChoosetheRightMotorOil

Fig.2.1.2MotorOilOiladditives:Tohelptheoilkeepyourenginecool,clean,andcorrosion-free,refinersblendinvariousadditives,whichcanaccountforasmuchas25percentofthecostoftheoil.Viscosityratings:Oilisratedandidentifiedbyitsviscosity,whichdeterminesitsabilitytoflow.Therearetwotypesofoilonthemarket:single-viscosityoilandmulti-viscosityoil.Almosteveryvehicleisdesignedtorunonmulti-viscosityoil.Thelowerthenumber,thethinnertheoilandthemoreeasilyitflows.In10W-40oil,forexample,thetwonumbersmeanthatit’satypeofmulti-viscosityoil.The10Wisanindexthatreferstohowtheoilflowsatlowtemperatures(inwinter);40referstohowitflowsathightemperatures.Tofindoutwhichviscosityforyourvehicle,lookinyourowner’smanualforanoilviscositychart.Oilclassificationcodes:ThestarburstsymbolonanoilcontainerlabelmeansthattheoilmeetsthecurrentengineprotectionstandardandfueleconomyrequirementsoftheInternationalLubricantStandardizationandApprovalCommittee(ILSAC),ajointeffortoftheU.S.andJapaneseautomobilemanufacturers.Fig.2.1.3OilClassificationCodes(a)APIstarburstsymbol;(b)APIdonutsymbolforgasolineengineoil;(c)APIdonutsymbolfordieselengineoil.Practice—MaintenanceManualReadingNote!?Engineoilshouldnotbeextracted,asarticlesofdirtmayremainintheoilpan.1.Jackupthevehicleatthepointsprovided.2.Removeundersidepanel.Warning!Dangerofscaldingfromdrainingoil!Wearprotectiveequipmentspecified.EngineOilandOilFilterChange3.Undothe2oildrainplugsandcollectengineoilinadisposalcontainer.Disposeofwasteoilinaccordancewithlegalrequirements.4.Cleanoildrainplugsandscrewinwithnewaluminumsealingring.Tighteningtorque50Nm(37ftlb.).

5.Undooilfilterwithspecialtool（專用工具）(releasekey)9204andunscrewit.6.Removeoilfilterhousingvertically（垂直地）downwards.Drainremainingoilintoadisposalcontainer.7.Removefilterelement（濾芯）.Removethefilterdownwardsanddisposeofitinaccordancewithlegalrequirements.Note!?DonotremoveO-ringwithasharpobject.?TheoilfilterhousingcontainsacutoutwithwhichtheO-ringcanberemoved.9.Install（安裝）filterelement.Note!?LightlyoilO-ringwheninstallingoilfilterhousing.10.Installoilfilterhousingandtightento25Nm(19ftlb.)Usingspecialtool(releasekey)9204.LightlyoiltheO-ringwhendoingthis.Tighteningtorque25Nm(19ftlb.).8.Cleanoilfilterhousing-1-andreplaceO-ringseal.CleanoilfilterhousingthoroughlyinsideandoutsideandreplacetheO-ring.CarefullyleverofftheO-ring.Theoilfilterhousingmustnotbedamagedduringthisprocedure.11.Fillwithengineoil.Theoilchangequantityis8.75litres（升）afteradrippingtimeofapprox.20minutes.12.Fittheundersidepanel.Task2.2CheckingDriveBeltLearningPreparationdrivebeltchecksparkplugintakefittingfastenthrottlebodypressurehotfilmmassairflowsensorlockingcliptensioningrollerKeyterms:傳動帶檢查，檢測火花塞進氣接頭緊固節(jié)氣門體壓力熱膜式空氣流量傳感器卡箍張緊輪Step1Amaintenancecaseisprovided;Step2Learntheprocessofcheckingdrivebeltviaamaintenancemanual;Step3Requirestudentstograspthekeytermsinthistask;Step4Trytodescribetheprocessofcheckingdrivebelt;Step5Studentsreadrelativematerial;Step6AssessmentPlanandImplement()1.Whenyouchangethesparkplugsyoushouldcheckthedrivebeltalso.()2.Thedrivebeltcanberemovedwhetheritishotornot.()3.Whenthedrivebeltisremovedwhenhot,itwillbedeformed.()4.Thethrottlebodycovershouldbepulledoffatanydirection.()5.ThepressurepipeisabovetheYpipe.AssessmentandFeedbackTrueorFalse()6.Thehotfilmmassairflowsensorisakindoftemperaturesensor.()7.Remainamarkonthesideofthedrivebeltwhenyoucheckit.()8.Whencrankingtheengine,thedeflectionrollersshouldalsobecheckedfordamage.()9.Ifthereisslighttearinarib,thedrivebeltmustbereplaced.()10.Whenthecrackisrunningtobaseofrib,thedrivebeltmustbereplaced.Adrivebeltisusedtodriveaccessoriesinstalledonyourcarengine,suchasanalternator（發(fā)電機）,waterpump,powersteeringpumpandairconditionercompressor.Sometimesadrivebeltcouldalsobecalleda“serpentinebelt”or“accessoriesbelt”.Somecarshaveasingledrivebeltrunningalltheaccessoriesandothersmayhavetwoormoredrivebelts.OldercarsusuallyusedV-shapedbelts,whiletoday’scarsuseV-ribbedbeltsthatareflatononesideandhaveribsontheotherside(showninthefollowingFig.2.2.1).2.2.1DriveBeltDrivebelttensioner（張緊裝置）Overtime,thedrivebeltstretches.Tocompensateforthisthereisabelttensionerthatkeepsthedrivebeltunderpropertension.Insomeoldercars,abelttensionerhadtobemanuallyadjustedfromtimetotime.Ifnotadjustedintime,thebeltwouldgetlooseandstartslipping,makingaloudwhistlingorsqueakingnoise.Commonlyyouwouldhearthisnoisewhenthecarisjuststartedcoldinthemorningorwhenturningthesteeringwheelallthewayleftorrighttothelimit.Mostofthenewercarshaveadrivebeltwithaspring-loadedself-adjustingtensionerthatmaintainstheproperbelttensionautomatically.DrivebeltproblemsAdrivebeltismadefromveryflexibleanddurablematerial,butitstillwearsovertime.Onaverage,adrivebeltcanlast3-4years.Impropertension,excessiveheat,engineoilleakingontothebeltandthepiecesofdebrisstuckbetweenthebeltribscancausethebelttowearfaster.Awornout（磨損的）beltmaycausesqueakingorwhistlingnoiseandabadlywornoutbeltcanbreak.(Youcanseecracksandmissingchunksinthefollowingfigure.)BadlyWornDriveBeltRemoveBeltsRemovalsimplyinvolvesreleasingthetensionandslippingtheoldbeltfromaroundthepulleys（皮帶輪）.Thereareafewcommonwaystoloosenthetensionandremoveit.Themethodyouusewilldependonthetypesofbracketsandhardwareholdingtheaccessoryinplace.Abelt-drivenaccessoryboltedtoaslitbracketcanbeloosenedandslidtowardthemotortoreducethetensionandfacilitateremovalofthebelt.Afteranewbeltisinplace,theaccessorycanbemovedbacktothelocationthatprovidesjusttherightamountoftension.Ifanaccessorybracketisequippedwithasquarehole,aratchetwrenchcanbeusedasalevertomoveit.Asocketwrenchwillworkasalevertomoveanaccessoryheldwithahexhead,andthosewithoutahexheadorasquareholecanbemovedwithacrowbar.2.2.2HowtoReplaceaVehicleDriveBelt

BeltReplacementDon’ttrytoguessthelengthofthebeltyou’llneed.Theyareavailableinmanydifferentlengthsandshapes.Savetimeandtroublebytakingtheoldonetotheautopartstore.Morethanlikely,theoldbeltisstretched,andthenewonewillbealittleshorter.Aslongasitisn’tlongerandisasclosetothecorrectsizeaspossible,itwillwork.Slipthenewbeltonaccordingtothediagram,securetheaccessories,andadjustthetensionregulator.Startthevehicle,turnontheairconditioner（空調）,andlistenforsquealing.Ifeverythingsoundsgood,thetensionisprobablycorrect.Checkforsquealingafewdayslater,andifabelthasloosened,tightenitasnecessary.However,becarefulnottoovertightenthebelt.Abeltthatistootightcandamagethepulleys.Practice—MaintenanceManualReadingNote!?Ifsparkplugs（火花塞）mustbechangedduringthecourseofmaintenanceoperations,thedrivebeltshouldbecheckedwhenthesparkplugsareremoved.Theenginecanthenbecrankedeasier.Warning!Riskofdamage?Neverremovedrivebeltwhenitishot.?Ifthedrivebeltisremovedwhenitishot,itcanbepulledoutofshapeanddamaged.CheckingDriveBelt1.Removethrottle（節(jié)氣門）bodycover.Pulloffcoververticallyupwards.2.RemoveYintakefitting.Todothis,pulltheleftandrightfasteningpinsonthethrottlebodyverticallyupwards.

3.DisconnectpressurepipeontheundersideoftheYpipe.4.UndotheYintakefittingleftandrightonthehotfilmmassairflowsensor.Todothis,pullthelockingclipsverticallyupwards.5.DisconnectthehotfilmmassairflowsensorandremovetheYpipefromthevehicle.6.Usingchalk,markthedrivebeltintheareaaroundthetensioningroller.7.Twistengineonvibrationdamperusingasocketwrench（套筒扳手）(a/f19)untilthechalkmarkisatthesameplaceagain.Whileturning,checkthedeflectionrollersofthedrivebeltonthecrankshaftfordamage.DamagesymptomsNote!?Thedrivebeltmustbereplacedifanyofthefollowingdamageoccurs:Task2.3CheckingCoolingSystemLearningPreparationcoolingsystemchecklevelantifreezecoolanttopupleakagepressureexpansiontankKeyterms:冷卻系統(tǒng)檢查、檢測水平，水準防凍劑冷卻液給…加滿泄露壓力膨脹水箱Step1Amaintenancecaseisprovided;Step2Learntheprocessofcheckingcoolingsystemviaamaintenancemanual;Step3Requirestudentstograspthekeytermsinthistask;Step4Trytodescribetheprocessofcheckingcoolingsystem;Step5Studentsreadrelativematerial;Step6AssessmentPlanandImplement()1.Theenginecoolantmustbechangedevery2years.()2.Whenreplacingortoppingupthecoolant,PorscheoriginalantifreezeorothertypesofantifreezearebothOK.()3.Thecoolingsystemmustbeopenedwhenthecoolantishot.()4.Youshouldwearglovestopreventfrombeingscalded.()5.Thatscrewingonthelidinananti-clockwisedirectionistoundoit.AssessmentandFeedbackTrueorFalse()6.Atestpressureofabout2.5barshouldbeappliedtothehose.()7.Thetestpressureappliedtocheckleakageofcoolingsystemmustbemaintainaconstantpressure.()8.Thecoolantlevelshouldbebetweenthe“min”and“max”.()9.Whenthecoveroftheexpansiontankislockedyoucanhearaclick.()10.Theradiatorcanbecleanedbyavacuumcleaner.Althoughgasolineengineshaveimprovedalot,theyarestillnotveryefficientatconvertingchemicalenergyintomechanicalpower.Mostoftheenergyinthegasoline（汽油）(perhaps70%)isconvertedintoheat,anditisthejobofthecoolingsystemtotakecareofthatheat.Asfuelisburnedintheengine,aboutone-thirdoftheheatenergyinthefuelisconvertedintopower.Anotherthirdgoesoutthroughtheexhaustpipe（排氣管）unused,andtheremainingthirdmustbehandledbythecoolingsystem.Thepurposeofthecoolingsystemistokeeptheengineatitsmostefficientoperatingtemperatureatallspeedsunderalldrivingconditions.2.3.1CoolingSystemAlthoughtheprimaryjobofthecoolingsystemistokeeptheenginefromoverheating（過熱）bytransferringthisheattotheair,italsohasseveralotherimportantjobs.Whentheengineiscold,componentswearoutfaster,andtheengineislessefficientandemitsmorepollution.Soanotherimportantjobofthecoolingsystemistoallowtheenginetoheatupasquicklyaspossible,andthentokeeptheengineataconstanttemperature.Therearetwotypicaltypesofcoolingsystem:water-coolingsystemandair-coolingsystem.Water-coolingsystemismorecommon.Thecoolingmedium,orcoolant,inthemiseitherwaterorsomelow-freezingliquid,calledantifreeze.Awater-coolingsystemconsistsoftheenginewaterjacket,thermostat,waterpump,radiator,radiatorcap,fan,fandrivebeltandnecessaryhoses.Fig.2.3.1showsthecomponentsofawater-coolingsystem.Asthevehicleisstarted,thewaterpump（水泵）beginscirculatingthecoolant.Thecoolantgoesthroughthecylinderblockfromthefronttotherear,andcirculatesaroundthecylinders.Thecoolantthenpassesupintothecylinderheadthroughtheholesintheheadgasket,andmovesforwardtocoolthesparkplugandexhaustvalveareasthroughinternalpassages.Fig.2.3.1CoolingSystem1-bypass;2-waterpump;3-thermostat;4-cylinderhead;5-cylinderblock;6-fanbelt;7-radiator;8-fan;9-radiatorpressurecapAfterleavingthecylinderhead（汽缸蓋）,thecoolantpassesthroughathermostatonthewaytotheradiator.Aslongasthecoolanttemperatureremainslow,thethermostat（節(jié)溫器）

staysclosed.Underthisconditionthecoolantflowsthroughthebypasstubeandreturnstothepumpforrecirculation.Asthecoolantheatsup,thethermostatgraduallyopenstoallowenoughhotcoolanttopassthroughtheradiator,andmaintaintheengineoperatingathighesttemperature.Fromthethermostat,thecoolantflowstotheinternalpassagesintheradiatorandisbeingcooledbytheairpassingthroughtheradiator.Thenthecoolantbackstothepump.Coolantdoesn’tgetusedupduringacar’snormaloperation.Ifthecoolantlevelisconsistentlylow,yourcarhasacoolantleak.Hereisamethodforyoutocheckthesituationoutyourself.1)Findthecoolantreservoir.Followthehosethatcomesfromthetopoftheradiatorcap（散熱器蓋）.Itwillleadtothecoolantreservoir.ItisusuallyaclearplastictankwithMAXandMINindicatorsontheoutside.2)Openthecapandaddcoolanttothecoolantreservoir,usingafunneltoavoidspilling.Coolantisamixtureofhalfantifreezeandhalfwater.InapinchitisOKtoaddonlywateroronlyantifreeze.2.3.2HowtoCheckandAddCoolant

3)Putthecapbackonthecoolantreservoir.4)Addcoolanttotheradiatoraswellifthereservoirwascompletelyempty.Makesuretheengineiscompletelycoolbeforeopeningtheradiatorcap.5)Someoldercarsdon’thaveacoolantreservoir;inthatcase,addthecoolantdirectlytotheradiator.Practice—MaintenanceManualReadingCoolant:checkingthelevelandantifreeze（防凍劑）protectioncontentNote!?Theenginecoolingsystemisfactory-filledwithacoolantthatdoesnotneedtobechanged.Thecoolantshouldnotbemixedwithothercoolants.?OnlyoriginalPorscheantifreezeprotectionshouldbeusedwhenreplacingortoppingupthecoolant.1.Openmaintenancecover.CheckingCoolingSystemCaution!Dangerofscalding!?Coolantscanbeextremelyhotandpressurised.?Onlyopencoolingsystemwhenitiscold.?Weargloves.2.Carefullyopenlid（蓋）onexpansiontank.Screwonlidinananti-clockwise（逆時針）direction.3.Checkantifreezeprotectioncontent.Ifitislowerthan-37°C,itshouldbecorrectedaccordingly.Thecoolantlevelmustnotdropbelowtheminimummark.

Note!?Thefollowingtablespecifieshowmuchcoolantmustbereplacedbypureantifreezeprotectioninordertoadjustthefreezingpointto-37°C.Measuredantifreezeprotectionin°CAntifreezeprotectionquantitytobeadded（inlitres）-59-108.5-157.5-207-255-303.5-351.5

2.Checktheenginecoolantlevel.Agraduatedwasherwithaminandamaxmarkingislocatedinthelockopeningintheexpansiontank.The“min”levelmustbecoveredwithcoolant.Checkingthecoolingsystemforleaks1.Checkthecoolingsystemforleaks.Todothis,applyatestpressureofapprox.1.5barusingthecoolingsystemtestdeviceandcheckhoseconnectionsforleakage.Thepressuremustnotdrop.3.Screwonthecoveroftheexpansiontankagainuntilitlockswithanaudibleclick.4.Closethemaintenancecover.5.Checkradiatorsforexternaldirt.Theradiatorsshouldnotcontaintoomuchdirt.Ifnecessary,theycanbecleanedusingavacuumcleanerwithabrushattachment.Task2.4ReplacingSparkPlugsLearningPreparation火花塞扭臂旋開，旋松泵點火線圈軟管線束專用工具電極間隙接合Keyterms:sparkplugtorquearmunscrewpumpignitioncoilhosewiringharnessspecialtoolelectrodegapengageStep1Amaintenancecaseisprovided;Step2Learntheprocessofreplacingsparkplugsviaamaintenancemanual;Step3Requirestudentstograspthekeytermsinthistask;Step4Trytodescribetheprocessofreplacingsparkplugs;Step5Studentsreadrelativematerial;Step6AssessmentPlanandImplement()1.Beforereplacingthesparkplugs,theignitionswitchmustbeoff.()2.Therearesixfasteningscrewsontheignitioncoilcover.()3.Inordertoavoidbreakingthedesigncover,aclothshouldbeplacedbetweenthecoverandthesecondaryairpump.()4.Theignitioncoilsareconnectedwithwiringharness.()5.Thesparkplugshouldberemovedbyaspecialtool(sparkplugwrench).AssessmentandFeedbackTrueorFalse()6.Anewsparkplugcanbeinstalledwithoutchecking.()7.Theelectrodegapforthesparkplugmustbe1.9mm.()8.Thenewsparkplugsshouldbetightenedto25Nm.()9.Theignitioncoilshouldbeengagedwithaclick.()10.The2rubbermountsmustbepressedinthebracket.Asparkplugisadevicefordeliveringelectriccurrentfromanignitionsystemtothecombustionchamber（燃燒室）toignitethecompressedair-fuelmixturebyanelectricspark.Itforceselectricitytoarcacrossagap,justlikeaboltoflightning.Theelectricitymustbeataveryhighvoltageinordertotravelacrossthegapandcreateagoodspark.Voltageatthesparkplugcanbeanywherefrom40,000to100,000volts.2.4.1SparkPlugFig.2.4.1SparkPlugThesparkplugmusthaveaninsulatedpassagewayforthishighvoltagetotraveldowntotheelectrode（電極）,whereitcanjumpthegapand,fromthere,beconductedintotheengineblockandgrounded.Theplugalsohastowithstandtheextremeheatandpressureinsidethecylinder,andmustbedesignedsothatdepositsfromfueladditivesdonotbuildupontheplug.

Fig.2.4.2SparkPlugCutaway1-connector(toplugwire);2-ceramic

insulator;3-gasket;4-electrodeSparkplugsuseaceramicinserttoisolate（絕緣）thehighvoltageattheelectrode,ensuringthatthesparkhappensatthetipoftheelectrodeandnotanywhereelseontheplug;thisinsertdoesdouble-dutybyhelpingtoburnoffdeposits.Ceramicisafairlypoorheatconductor,sothematerialgetsquitehotduringoperation.Thisheathelpstoburnoffdepositsfromtheelectrode.Someautomotivesrequireahotplug.Thistypeofplugisdesignedwithaceramicinsertthathasasmallercontactareawiththemetalpartoftheplug.Thisreducestheheattransferfromtheceramic,makingitrunhotterandthusburnawaymoredeposits.Coldplugsaredesignedwithmorecontactarea,sotheyruncooler.Fig.2.4.3HotPlugandColdPlugThemanufacturerwillselecttherighttemperatureplugforeachcar.Somecarswithhigh-performance（高性能）enginesnaturallygeneratemoreheat,sotheyneedcolderplugs.Ifthesparkpluggetstoohot,itcouldignitethefuelbeforethesparkfires;soitisimportanttostickwiththerighttypeofplugforyourcar.Thegapbetweenthecenterandsideelectrodesofasparkplugmustbeanexactdistance,otherwise,yourplugsdon’tfireefficiently.Adjustingthedistancebetweenthetwoelectrodesiscalledgappingyoursparkplugs.Youneedafeelergaugetogapyoursparkplugsproperly.Thefollowingishowtosetthegapofasparkplug:1)Cleanyoursparkplug.Ifyou’reregappingausedplug,makesurethatit’sclean(gentlyscrubitwithawirebrush).Ifyou’reusinganewplug,itshouldbecleanandnew-looking,withthetipofthesideelectrodecenteredoverthecenterelectrode.Youshouldn’tseeanycracks（裂紋）orbubblesintheporcelaininsulator,andthethreadsshouldbeunbroken.2.4.2HowtoGapYourSparkPlugs

2)Selectthepropernumberonyourfeelergauge,andrunthegaugebetweentheelectrodes.Tofindtherightgauge,lookforaspecsheetforyourautomobileintheowner’smanual,oryoucangettheinformationfromalocalautopartsstore.Ifthegaugedoesn’tgothrough,orifitgoesthroughtooeasilywithouttouchingtheelectrodes,youneedtoadjustthedistancebetweentheelectrodes.Fig.2.4.4ChecktheGapoftheSparkPlugFig.2.4.5AFeelerGauge3)Adjustthegapasnecessary.Ifthewiredidn’tgothrough,thegapistoonarrow.Hookthepartofthefeelergauge（塞尺）that’susedforbendingelectrodesunderthesideelectrodeandtugverygentlytowidenthegap.Afeelergaugeisshownhere.Ifthegaugegoesthroughtooeasilywithouttouchingtheelectrodes,thegapiswide.Pressthesideelectrodeverygentlyagainstaclean,mar-proofsurfaceuntilit’sslightlybentdowntowardthecenterelectrode.4)Runthegaugethroughthegapagain.Youwantthegaugetogothroughfairlyeasily,justcatchingtheelectrodesasitpasses.Ifyoukeepadjustingthegaptoonarrowortoowide,don’tfeelbad.Mostpeoplegothroughthe“toolarge—toosmall—toolarge”acoupleoftimesforeachplug,especiallytheperfectionists.Practice—MaintenanceManualReadingNote!?Ignitionisoff,ignitionkeyisremoved.Removingdesigncoverofcylinderbank5-8Note!?Placeaclothbetweensecondaryairpumpanddesigncovertoavoidscratchingcover.ReplacingSparkPlugs1.Unscrewthe4fasteningscrews（緊固螺釘）ontheignitioncoilcover.2.Removedesigncoverofcylinderbank5-8.Using2hands,liftthecoverslightlyattheedgefacingtheintakesystemuntilitsnapsoutofitsholder.

Liftdesigncoveratthefrontandpullitout.Replacingsparkplugs1.Pulloffthelowerhoseonsecondaryairpump5-8.2.Disconnectthe8ignitioncoils（點火線圈）fromwiring