3发动机ppt课件

汽车实用英语,AutomobileEnglish,TaskThreeAutomobileEngine,Objectives1.Toknowtheenginecrankshaftandconnectingrodassembly.2.Toknowthevalveandvalvetrain.3.TolearntheAutomobilecoolingsystem.4.Tolearnhowthelubricationsystemworks.,2,1,1._,2._,EngineConstruction,FuelSystem,PartWarmupKnowabouttwomechanismsandfivesystems,3,1,3._,4._,CoolingSystem,LubricatingSystem,PartWarmupKnowabouttwomechanismsandfivesystems,4,1,5._,6._,StartingSystem,IgnitionSystem,PartWarmupKnowabouttwomechanismsandfivesystems,5,Grasptheusefulwordsandphrasesfuelconsumptionequipwith,PartListeningandspeaking,6,A:Hi，thisismynewcar.Iboughtitlastmonth.B:Oh!Itsbeautiful.Howisthefuelconsumption?A:Itsveryeconomiconfuel.B:Whatkindofenginedoesthecarhave?A:Itsequippedwithanadvanceddieselengine.B:Dieselengine?A:Yeah.B:Thatsincredible!A:Youcantryit.B:OK，thankyou.,PartListeningandspeakingDialogueANewDieselCar,7,Enginecrankshaftandconnectingrodassemblyisoneoftheassembliesintheengine.Itconvertsthermalenergyintomechanicalenergyusedtodrivethevehicle.Thisassemblyiscomposedofpistons，pistonrings，connectingrodsandcrankshafts.,PartReadingPassageOneCrankshaftandConnectingRodAssembly,8,Enginevalveandvalvetrainistheotherassemblyintheengine.Thevalveandvalvetrainprovidestimelyadmissionofthefreshchargeintothecylindersandexhaustgasfromthem.Forthispurpose，thevalvesatdefinitemomentsopenandclosetheintakeandexhaustportsinthecylinderhead，throughwhichthecylindersconnecttotheintakeandexhaustmanifold.,PartReadingPassageOneValveandValveTrain,9,Thevalveandvalvetrainconsistsofthevalvesandamechanismthatopensandclosesthem.Thistypicaltrainiscomposedofvalve，valvespring，valveguide，tappet，pushrod，rockerarm，camshaft，timinggear，timingbelt，tensioner，etc.,PartReadingPassageOneValveandValveTrain,10,1.Enginecrankshaftandconnectingrodassemblyiscomposedof，and.2.Thevalveandvalvetrainiscomposedof，valvespring，rockerarm，tensioner，etc.,pistons,PartReadingPassageOneExercises,pistonrings,connectingrods,crankshafts,valve,valveguide,tappet,pushrod,camshaft,timinggear,timingbelt,Fillintheblanksbelow.,11,PartReadingPassageTwoAutomobileCoolingSystem,Componentsofwatercoolingsystem,1.louver2.radiator3.radiatorcap4.fan5.pump6.thermostat7.watertemperaturegauge8.waterjacketofcylinderhead9.waterdistributionpipe10.outletvalve,1.百叶窗2.散热器3.散热器盖4.风扇5.水泵6.节温器7.冷却液温度表8.气缸盖水套9.分水管10.放水阀,12,Anautomobilescoolingsystemisthecollectionofpartsandsubstances（coolants）thatworktogethertomaintaintheenginestemperatureatoptimallevels.Comprisingmanydifferentcomponentssuchaswaterpump，coolant，athermostat，etc.，thesystemenablessmoothandefficientfunctioningoftheengineatthesametimeprotectingitfromdamage.,PartReadingPassageTwoAutomobileCoolingSystem,13,Whileitsrunning，anautomobilesenginegeneratesenormousamountsofheat.Eachcombustioncycleentailsthousandsofcontrolledexplosionstakingplaceeveryminuteinsidetheengine.Iftheautomobileracesonandtheheatgeneratedwithinisntdissipated，itwouldcausetheenginetoself-destruct.,PartReadingPassageTwoAutomobileCoolingSystem,14,Hence，itisimperativetoconcurrentlyremovethewasteheat.Whilethewasteheatisalsodissipatedthroughtheintakeofcoolairandexitofhotexhaustgases，theenginescoolingsystemisexplicitlymeanttokeepthetemperaturewithinlimits.,PartReadingPassageTwoAutomobileCoolingSystem,15,Thecoolingsystemessentiallycomprisespassagesinsidetheengineblockandheads，apumptocirculatethecoolant，athermostattocontroltheflowofthecoolant，aradiatortocoolthecoolantandaradiatorcapcontrolsthepressurewithinthesystem.,PartReadingPassageTwoAutomobileCoolingSystem,16,Inordertoachievethecoolingaction，thesystemcirculatestheliquidcoolantthroughpassagesintheengineblockandheads.Asitrunsthrough，thecoolantabsorbsheatbeforereturningtotheradiator，tobecooleditself.Next，thecooleddowncoolantisrecirculatedandthecyclecontinuestomaintaintheenginestemperatureattherightlevels.,PartReadingPassageTwoAutomobileCoolingSystem,17,Thecoolingsystemessentiallycomprisespassagesinsidetheengineblockand，atocirculatethecoolant，atocontroltheflowofthecoolant，atocoolthecoolantandaradiatorcapcontrolsthepressurewithinthesystem.,heads,PartReadingPassageTwoExercises,pump,thermostat,radiator,Fillintheblanksbelow.,18,TranslatethefollowingparagraphintoChinese.Comprisingmanydifferentcomponentssuchaswaterpump，coolant，athermostat，etc.，thesystemenablessmoothandefficientfunctioningoftheengineatthesametimeprotectingitfromdamage.,PartReadingPassageTwoExercises,汽车冷却系统包括水泵、冷却液、恒温器等组件，能够使发动机平稳高效运行，同时使其免受损害。,19,1,1._,LubricantPassageWay,PartReadingPassageThreeHowtheLubricationSystemWorks,20,Lubricationisemployedtoreducefrictionbyinterposingafilmbetweenrubbingparts.Thelubricationsystemmustcontinuouslyreplacethefilm.Thelubricantscommonlyemployedarerefinedfromcrudeoilafterthefuelshavebeenremoved.,PartReadingPassageThreeHowtheLubricationSystemWorks,21,Theirviscositiesmustbeappropriateforeachengine，andtheoilmustbesuitablefortheseverityoftheoperatingconditions.Oilsareimprovedwithadditivesthatreduceoxidation，inhibitcorrosion，andactasdetergentstodispersedeposit-forminggumsandsolidcontaminants.Motoroilsalsoincludeanantifoamingagent.,PartReadingPassageThreeHowtheLubricationSystemWorks,22,Varioussystemsofnumbersareusedtodesignateoilviscosity；thelowerthenumber，thelighterthebodyoftheoil.Viscositymustbechosentomatchtheflowrateofoilthroughaparttothedesignedcoolingrequirementsofthepart.,PartReadingPassageThreeHowtheLubricationSystemWorks,23,Iftheoilistoothickitwillnotflowthroughthepartfastenoughtoproperlydissipateheat.Certainoilscontainadditivesthatopposetheirchangeinviscositybetweenwinterandsummer.,PartReadingPassageThreeHowtheLubricationSystemWorks,24,1,4._,Gearoilpump（schematic）,PartReadingPassageThreeHowtheLubricationSystemWorks,1._,OilCooler,2._,OilFilter,3._,LubricationOil,25,Oilfilters，ifregularlyserviced，canremovesolidcontaminantsfromcrankcaseoil，butchemicalreactionsmayformliquidsthatarecorrosiveanddamaging.Depletionoftheadditivesalsolimitstheusefullifeoflubricatingoils.,PartReadingPassageThreeHowtheLubricationSystemWorks,26,Thelubricationsystemisfedbytheoilpanthatformsthelowerenclosureoftheengine.Oilistakenfromthepanbyagearoilpump，andispassedthroughaoilstraineranddeliveredunderpressuretoasystemofpassagesorchannelsdrilledthroughtheengine.,PartReadingPassageThreeHowtheLubricationSystemWorks,27,Virtuallyallmodernenginesusefull-flowtypeoilfilters.Filteredoilissuppliedunderpressuretocrankshaftandcamshaftmainbearings.,PartReadingPassageThreeHowtheLubricationSystemWorks,28,Adjacentcrankthrowsaredrilledtoenabletheoiltoflowfromthesupplyatthemainbearingstothecrankpins.Leakingoilfromallofthecrankshaftbearingsissprayedonthecylinderwalls，cams，andupintothepistonstolubricatethepistonpins.,PartReadingPassageThreeHowtheLubricationSystemWorks,29,Additionalpassagesintersectthecam-followeropeningsandsupplyoiltohydraulicvalvelifterswhenused.Aspring-loadedpressure-reliefvalvemaintainsthepressureattheproperlevel.Oilisimportantforbothlubricationandcooling.,PartReadingPassageThreeHowtheLubricationSystemWorks,30,1.Lubricationisemployedtoreducefrictionbyinterposingafilmbetweenrubbingparts._2.Oilfilters，ifregularlyserviced，canremovesolidcontaminantsfromcrankcaseoil，butchemicalreactionsmayformliquidsthatarecorrosiveanddamaging._,6,TranslatethefollowingsentencesintoChinese.,润滑的作用是通过油膜减少摩擦部件之间的摩擦。,机油滤清器，如果定期加以保养，可以从曲轴箱有效去除固体污染物，但化学反应可能形成具有腐蚀性和破坏性的液体。,PartReadingPassageThreeExercises,31,Thislightindicatestheengineoilpressure，nottheoillevel.However，ifyourengineoillevelislow，itwillaffecttheoilpressure.ThelightshouldcomeoneverytimeyourignitionkeyisturnedtoONorSTARTandgooutwhentheenginestarts.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,32,Ifthelightstaysonorturnsonwhiletheengineisrunning，youhavelostoilpressureandcontinuedoperationwillcausesevereenginedamage.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,33,Ifyouloseoilpressure:（1）Pullofftheroadassoonasitissafelypossible.（2）Shutofftheengineimmediately.Ifyoudonotstoptheengineassoonaspossible，severeenginedamagecouldoccur.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,34,Ifyouloseoilpressure:（3）Checktheengineoillevel，followingtheinstructionsunderCheckingandAddingEngineOilintheOwnerGuide.Toensureanaccuratereading，yourcarshouldbeonlevelground.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,35,Ifyouloseoilpressure:（4）Ifthelevelislow，addonlyasmuchoilasnecessarybeforeyoustarttheengineagain.Donotoverfill.Donotoperatetheengineagain，ifthelightison，regardlessoftheoillevel.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,36,PartMaintenanceandrepairExercises,Answerthefollowingquestions.Ifyouloseoilpressure，whatshouldwedo？,37,Theexhaustemissionsofautomotiveenginescontainanumberofharmfulpollutants.Inordertominimizetheamountofharmfulpollutantsbeingproduced，manufactureshavedevelopedautomotiveemissioncontrols.,PartOutwardBoundAutomobileexhaustgases,38,Thefollowingisalistoftheharmfulexhaustgasesmanufacturesplantoreduce，whichincludeshowthegasesareformedandwhytheyaredangerous.,PartOutwardBoundAutomobileexhaustgases,39,CarbonMonoxide（CO）CarbonMonoxideconsistsofcarbonandoxygen.Thiscolorless，odorless，poisonousgasistheproductofincompletecombustion.Byweight，carbonmonoxideaccountsforthe47%ofairpollution.,PartOutwardBoundAutomobileexhaustgases,40,Hydrocarbon（CH）Hydrocarbonsconsistofcarbonandhydrogen.Hydrocarbonsareemittedinanunburnedformfromequipmentwhichusesapetroleumproductasasourceoffuel.Hydrocarbonsareoneofthekeyelementsresponsiblefortheproductionofphotochemicalsmog.,PartOutwardBoundAutomobileexhaustgases,41,OxidesofNitrogen（NOx）Oxidesofnitrogenconsistofnitrogencombinedwithvaryingamountsofoxygen.NOxareproducedbyheatandpressureduringthecombustionprocess.NOxarealsoamaincomponentinsmog.,PartOu