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汽车构造英文版-免费下载版CHAPTER1AUTOMOTIVEBASICS?PrincipalComponentsToday'saveragecarcontainsmorethan15,000separate,individualpartsthatmustworktogether.Thesepartscangroupedintofourmajorcategories:engine,body,chassisandelectricalequipment.?EngineTheengineactsasthepowerunit.Theinternalcombustionengineismostcommon:thisobtainsitspowerbyburningaliquidfuelinsidetheenginecylinder.Therearetwotypesofengine:gasoline(alsocalledaspark-ignitionengine)anddiesel(alsocalledacompression-ignitionengine).Bothenginesarecalledheatengines;theburningfuelgeneratesheatwhichcausesthegasinsidethecylindertoincreaseitspressureandsupplypowertorotateashaftconnectedtothetransmission.?BodyAnautomobilebodyisasheetmetalshellwithwindows,doors,ahood,andatrunkdeckbuiltintoit.Itprovidesaprotectivecoveringfortheengine,passengers,andcargo.Thebodyisdesignedtokeeppassengerssafeandcomfortable.Thebodystylingprovidesanattractive,colorful,modernappearanceforthevehicle.?ChassisThechassisisanassemblyofthosesystemsthatarethemajoroperatingpartofavehicle.Thechassisincludesthetransmission,suspension,steering,andbrakesystems.Transmissionsystems―conveysthedrivetothewheels.Themaincomponentsareclutch,gearbox,driveshaft,finaldrive,anddifferential.Suspension―absorbstheroadshocks.Steering―controlsthedirectionofthemovement.Brake―slowsdownthevehicle.?Electrical?EquipmentTheelectricalsystemsupplieselectricityfortheignition,horn,lights,heater,andstarter.Theelectricitylevelismaintainedbyachargingcircuit.Thiscircuitconsistsofthebattery,alternator(orgenerator).Thebatterystoreselectricity.Thealternatorchangestheengine'smechanicalenergyintoelectricalenergyandrechargesthebattery.NewWordsPrincipalcomponent?主要部件category?种类，类型body?车身chassis?底盘layout?布置powerunit?动力装置internalcombustionengine?内燃机cylinder?汽缸gasoline?汽油spark?火花ignition?点燃，点火diesel?柴油机compression?压缩shaft?轴transmission?传动系sheetmetal?金属板shell?外壳hood?（发动机）罩trunkdeck?行李舱盖cargo?货物styling?样式assembly?总成，装配suspension?悬挂，悬置shock?冲击steering?转向，操纵brake?刹车，制动器clutch?离合器gearbox?变速器driveshaft?传动轴finaldrive?主减速器，后桥differential?差速器slowdown?（使）慢下来，减速horn?喇叭starter?起动机charge?充电alternator?交流发电机ReviewQuestions1.Listthemainpartsofanautomobile2.Whatarethecommontypesofavehicleaccordingtobodystyling3.Whichsystemsdoesachassisincludeandwhatarethemainfunctionsofthechassis4.WhyaresuspensionsystemsusedonvehiclesCHAPTER2INTERNALCOMBUSTIONENGINEprincipleofoperation2.1.1EngineandpowerEngineisusedtoproducepower.Thechemicalenergyinfuelisconvertedtoheatbytheburningofthefuelatacontrolledrate.Thisprocessiscalledcombustion.Ifenginecombustionoccurswiththepowerchamber.,theengineiscalledinternalcombustionengine.Ifcombustiontakesplaceoutsidethecylinder,theengineiscalledanexternalcombustionengine.Engineusedinautomobilesareinternalcombustionheatengines.Heatenergyreleasedinthecombustionchamberraisesthetemperatureofthecombustiongaseswiththechamber.Theincreaseingastemperaturecausesthepressureofthegasestoincrease.Thepressuredevelopedwithinthecombustionchamberisappliedtotheheadofapistontoproduceausablemechanicalforce,whichisthenconvertedintousefulmechanicalpower.2.1.2EngineTermsLinkingthepistonbyaconnectingrodtoacrankshaftcausesthegastorotatetheshaftthroughhalfaturn.Thepowerstroke“usesup”thegas,someansmustbeprovidedtoexpeltheburntgasandrechargethecylinderwithafreshpetrol-airmixture:thiscontrolofgasmovementisthedutyofthevalves;aninletvalveallowsthenewmixturetoenterattherighttimeandanexhaustvalveletsouttheburntgasafterthegashasdoneitsjob.Enginetermsare:TDC(TopDeadCenter):thepositionofthecrankandpistonwhenthepistonisfartherawayfromthecrankshaft.BDC(BottomDeadCenter):thepositionofthecrankandpistonwhenthepistonisnearesttothecrankshaft.Stroke:thedistancebetweenBDCandTDC;strokeiscontrolledbythecrankshaft.Bore:theinternaldiameterofthecylinder.Sweptvolume:thevolumebetweenTDCandBDC.Enginecapacity:thisisthesweptvolumeofallthecylinder.afour-strokehavingacapacityoftwoliters(2000cm)hasacylindersweptvolumeof50cm.Clearancevolume:thevolumeofthespaceabovethepistonwhenitisatTDC.Compressionratio=(sweptvol+clearancevol)\(clearancevol)Two-stroke:apowerstrokeeveryrevolutionofthecrank.Four-stroke:apowerstrokeeveryotherrevolutionofthecrank..2.1.3TheFour-strokeSpark-ignitionEngineCycleThespark-ignitionengineisaninternal-combustionenginewithexternallysuppliedinignition,whichconvertstheenergycontainedinthefueltokineticenergy.Thecycleofoperationsisspreadoverfourpistonstrokes.Tocompletethefullcycleittakestworevolutionsofthecrankshaft.Theoperatingstrokesare:Thisstrokeintroducesamixtureofatomizedgasolineandairintothecylinder.Thestrokestartswhenthepistonmovesdownwardfromapositionnearthetopofthecylinder.Asthepistonmovesdownward,avacuum,orlow-pressurearea,iscreated.Duringtheintakestroke,oneoftheportsisopenedbymovingtheinletvalve.Theexhaustvalveremainstightlyclosed.CompressionstrokeAsthepistonmovesupwardtocompressthefuelmixturetrappedinthecylinder,thevalvesareclosedtightly.Thiscompressionactionheatstheair/fuelmixtureslightlyandconfinesitwithinasmallareacalledthecombustionchamber.PowerstrokeJustbeforethepistonrea