3发动机ppt课件

1、汽车实用英语,AutomobileEnglish,TaskThreeAutomobileEngine,Objectives1.Toknowtheenginecrankshaftandconnectingrodassembly.2.Toknowthevalveandvalvetrain.3.TolearntheAutomobilecoolingsystem.4.Tolearnhowthelubricationsystemworks.,2,1,1._,2._,EngineConstruction,FuelSystem,PartWarmupKnowabouttwomechanismsandfives

2、ystems,3,1,3._,4._,CoolingSystem,LubricatingSystem,PartWarmupKnowabouttwomechanismsandfivesystems,4,1,5._,6._,StartingSystem,IgnitionSystem,PartWarmupKnowabouttwomechanismsandfivesystems,5,Grasptheusefulwordsandphrasesfuelconsumptionequipwith,PartListeningandspeaking,6,A:Hi，thisismynewcar.Iboughtitl

3、astmonth.B:Oh!Itsbeautiful.Howisthefuelconsumption?A:Itsveryeconomiconfuel.B:Whatkindofenginedoesthecarhave?A:Itsequippedwithanadvanceddieselengine.B:Dieselengine?A:Yeah.B:Thatsincredible!A:Youcantryit.B:OK，thankyou.,PartListeningandspeakingDialogueANewDieselCar,7,Enginecrankshaftandconnectingrodass

4、emblyisoneoftheassembliesintheengine.Itconvertsthermalenergyintomechanicalenergyusedtodrivethevehicle.Thisassemblyiscomposedofpistons，pistonrings，connectingrodsandcrankshafts.,PartReadingPassageOneCrankshaftandConnectingRodAssembly,8,Enginevalveandvalvetrainistheotherassemblyintheengine.Thevalveandv

5、alvetrainprovidestimelyadmissionofthefreshchargeintothecylindersandexhaustgasfromthem.Forthispurpose，thevalvesatdefinitemomentsopenandclosetheintakeandexhaustportsinthecylinderhead，throughwhichthecylindersconnecttotheintakeandexhaustmanifold.,PartReadingPassageOneValveandValveTrain,9,Thevalveandvalv

6、etrainconsistsofthevalvesandamechanismthatopensandclosesthem.Thistypicaltrainiscomposedofvalve，valvespring，valveguide，tappet，pushrod，rockerarm，camshaft，timinggear，timingbelt，tensioner，etc.,PartReadingPassageOneValveandValveTrain,10,1.Enginecrankshaftandconnectingrodassemblyiscomposedof，and.2.Thevalv

7、eandvalvetrainiscomposedof，valvespring，rockerarm，tensioner，etc.,pistons,PartReadingPassageOneExercises,pistonrings,connectingrods,crankshafts,valve,valveguide,tappet,pushrod,camshaft,timinggear,timingbelt,Fillintheblanksbelow.,11,PartReadingPassageTwoAutomobileCoolingSystem,Componentsofwatercoolings

8、ystem,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）thatworktogethertomain

9、taintheenginestemperatureatoptimallevels.Comprisingmanydifferentcomponentssuchaswaterpump，coolant，athermostat，etc.，thesystemenablessmoothandefficientfunctioningoftheengineatthesametimeprotectingitfromdamage.,PartReadingPassageTwoAutomobileCoolingSystem,13,Whileitsrunning，anautomobilesenginegenerates

10、enormousamountsofheat.Eachcombustioncycleentailsthousandsofcontrolledexplosionstakingplaceeveryminuteinsidetheengine.Iftheautomobileracesonandtheheatgeneratedwithinisntdissipated，itwouldcausetheenginetoself-destruct.,PartReadingPassageTwoAutomobileCoolingSystem,14,Hence，itisimperativetoconcurrentlyr

11、emovethewasteheat.Whilethewasteheatisalsodissipatedthroughtheintakeofcoolairandexitofhotexhaustgases，theenginescoolingsystemisexplicitlymeanttokeepthetemperaturewithinlimits.,PartReadingPassageTwoAutomobileCoolingSystem,15,Thecoolingsystemessentiallycomprisespassagesinsidetheengineblockandheads，apum

12、ptocirculatethecoolant，athermostattocontroltheflowofthecoolant，aradiatortocoolthecoolantandaradiatorcapcontrolsthepressurewithinthesystem.,PartReadingPassageTwoAutomobileCoolingSystem,16,Inordertoachievethecoolingaction，thesystemcirculatestheliquidcoolantthroughpassagesintheengineblockandheads.Asitr

13、unsthrough，thecoolantabsorbsheatbeforereturningtotheradiator，tobecooleditself.Next，thecooleddowncoolantisrecirculatedandthecyclecontinuestomaintaintheenginestemperatureattherightlevels.,PartReadingPassageTwoAutomobileCoolingSystem,17,Thecoolingsystemessentiallycomprisespassagesinsidetheengineblockan

14、d，atocirculatethecoolant，atocontroltheflowofthecoolant，atocoolthecoolantandaradiatorcapcontrolsthepressurewithinthesystem.,heads,PartReadingPassageTwoExercises,pump,thermostat,radiator,Fillintheblanksbelow.,18,TranslatethefollowingparagraphintoChinese.Comprisingmanydifferentcomponentssuchaswaterpump

15、，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,Lubricationisemployed

16、toreducefrictionbyinterposingafilmbetweenrubbingparts.Thelubricationsystemmustcontinuouslyreplacethefilm.Thelubricantscommonlyemployedarerefinedfromcrudeoilafterthefuelshavebeenremoved.,PartReadingPassageThreeHowtheLubricationSystemWorks,21,Theirviscositiesmustbeappropriateforeachengine，andtheoilmus

17、tbesuitablefortheseverityoftheoperatingconditions.Oilsareimprovedwithadditivesthatreduceoxidation，inhibitcorrosion，andactasdetergentstodispersedeposit-forminggumsandsolidcontaminants.Motoroilsalsoincludeanantifoamingagent.,PartReadingPassageThreeHowtheLubricationSystemWorks,22,Varioussystemsofnumber

18、sareusedtodesignateoilviscosity；thelowerthenumber，thelighterthebodyoftheoil.Viscositymustbechosentomatchtheflowrateofoilthroughaparttothedesignedcoolingrequirementsofthepart.,PartReadingPassageThreeHowtheLubricationSystemWorks,23,Iftheoilistoothickitwillnotflowthroughthepartfastenoughtoproperlydissi

19、pateheat.Certainoilscontainadditivesthatopposetheirchangeinviscositybetweenwinterandsummer.,PartReadingPassageThreeHowtheLubricationSystemWorks,24,1,4._,Gearoilpump（schematic）,PartReadingPassageThreeHowtheLubricationSystemWorks,1._,OilCooler,2._,OilFilter,3._,LubricationOil,25,Oilfilters，ifregularly

20、serviced，canremovesolidcontaminantsfromcrankcaseoil，butchemicalreactionsmayformliquidsthatarecorrosiveanddamaging.Depletionoftheadditivesalsolimitstheusefullifeoflubricatingoils.,PartReadingPassageThreeHowtheLubricationSystemWorks,26,Thelubricationsystemisfedbytheoilpanthatformsthelowerenclosureofth

21、eengine.Oilistakenfromthepanbyagearoilpump，andispassedthroughaoilstraineranddeliveredunderpressuretoasystemofpassagesorchannelsdrilledthroughtheengine.,PartReadingPassageThreeHowtheLubricationSystemWorks,27,Virtuallyallmodernenginesusefull-flowtypeoilfilters.Filteredoilissuppliedunderpressuretocrank

22、shaftandcamshaftmainbearings.,PartReadingPassageThreeHowtheLubricationSystemWorks,28,Adjacentcrankthrowsaredrilledtoenabletheoiltoflowfromthesupplyatthemainbearingstothecrankpins.Leakingoilfromallofthecrankshaftbearingsissprayedonthecylinderwalls，cams，andupintothepistonstolubricatethepistonpins.,Par

23、tReadingPassageThreeHowtheLubricationSystemWorks,29,Additionalpassagesintersectthecam-followeropeningsandsupplyoiltohydraulicvalvelifterswhenused.Aspring-loadedpressure-reliefvalvemaintainsthepressureattheproperlevel.Oilisimportantforbothlubricationandcooling.,PartReadingPassageThreeHowtheLubricatio

24、nSystemWorks,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

25、。,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.,P

26、artMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,32,Ifthelightstaysonorturnsonwhiletheengineisrunning，youhavelostoilpressureandcontinuedoperationwillcausesevereenginedamage.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,33,Ifyouloseoilpressure:（1）Pullofftheroada

27、ssoonasitissafelypossible.（2）Shutofftheengineimmediately.Ifyoudonotstoptheengineassoonaspossible，severeenginedamagecouldoccur.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,34,Ifyouloseoilpressure:（3）Checktheengineoillevel，followingtheinstructionsunderCheckingandAddingEngineOili

28、ntheOwnerGuide.Toensureanaccuratereading，yourcarshouldbeonlevelground.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,35,Ifyouloseoilpressure:（4）Ifthelevelislow，addonlyasmuchoilasnecessarybeforeyoustarttheengineagain.Donotoverfill.Donotoperatetheengineagain，ifthelightison，regardl

29、essoftheoillevel.,PartMaintenanceandrepairHowtoDealWithEngineOilPressureWarningLight,36,PartMaintenanceandrepairExercises,Answerthefollowingquestions.Ifyouloseoilpressure，whatshouldwedo？,37,Theexhaustemissionsofautomotiveenginescontainanumberofharmfulpollutants.Inordertominimizetheamountofharmfulpol

30、lutantsbeingproduced，manufactureshavedevelopedautomotiveemissioncontrols.,PartOutwardBoundAutomobileexhaustgases,38,Thefollowingisalistoftheharmfulexhaustgasesmanufacturesplantoreduce，whichincludeshowthegasesareformedandwhytheyaredangerous.,PartOutwardBoundAutomobileexhaustgases,39,CarbonMonoxide（CO

31、）CarbonMonoxideconsistsofcarbonandoxygen.Thiscolorless，odorless，poisonousgasistheproductofincompletecombustion.Byweight，carbonmonoxideaccountsforthe47%ofairpollution.,PartOutwardBoundAutomobileexhaustgases,40,Hydrocarbon（CH）Hydrocarbonsconsistofcarbonandhydrogen.Hydrocarbonsareemittedinanunburnedfor

32、mfromequipmentwhichusesapetroleumproductasasourceoffuel.Hydrocarbonsareoneofthekeyelementsresponsiblefortheproductionofphotochemicalsmog.,PartOutwardBoundAutomobileexhaustgases,41,OxidesofNitrogen（NOx）Oxidesofnitrogenconsistofnitrogencombinedwithvaryingamountsofoxygen.NOxareproducedbyheatandpressureduringthecombustionprocess.NOxarealsoamaincomponentinsmog.,PartOu