车辆工程外文翻译.docx

车辆工程外文翻译.docx

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车辆工程外文翻译

（本文截取的是一篇国外学生的毕业论文中的一段论文名字是“AComprehensiveThermalManagementSystemModelforHybridElectricVehicles”）

Theautomotiveindustryisfacingunprecedentedchallengesduetoenergyandenvironmentalissues.Theemissionregulationisbecomingstrictandthepriceofoilisincreasing.Thus,theautomotiveindustryrequireshigh-efficiencypowertrainsforautomobilestoreducefuelconsumptionandemissions.Amonghigh-efficiencypowertrainvehicles,Hy-bridElectricVehicles（HEVs）areunderdevelopmentandinproductionasonepotentialsolutiontotheseproblems.Thus,oneofthemostcriticalobjectivesoftheHEVdevelopmentisimprovingfueleconomy.Therearemanywaysofmaximizingthefuelecono-myofavehiclesuchasbrakepowerregeneration，efficientengineoperation，parasiticlossminimization，reductionofvehicleaerodynamicdrag,andengineidlestop.Figure1comparesthebalanceoftheenergyofaconventionalvehiclewithahybridelectricvehicle。

AscanbeseeninFigure1,thehybridvehiclesavesfuelbyutilizingengineidlestop,brakepowerregeneration,andefficientengineoperation.Figure1alsoshowsthatthefuelconsumedbytheaccessories,whichincludeVehicleCoolingSystem（VCS）,ClimateControlSystem（CCS）,andelectricaccessories,isnotnegligiblecomparedwiththefuelconsumedbythevehiclepropulsionsystem.Inaddition,theportionoftheenergyconsumptionoftheaccessoriesinHEVsisbiggerthanthatofconventionalvehicles.Thisobservationsuggeststhattheefficientaccessorysystem,particularlytheVCSandCCS,ismoreimportantinhigh-efficiencyvehiclesbecausetheyhavemoreeffectonthefueleconomy.Theeffectoftheauxiliaryloadonthefueleconomyofhigh-efficiencyvehiclesstudiedbyFarringtonetal[2].Theyexaminedtheeffectofauxiliaryloadonvehiclefueleconomyviaafocusonclimatecontrolsystem.Figure2comparestheimpactofauxiliaryload,i.e.thepowerconsumedbyaccessorysystems,onthefueleconomyoftheconventionalandhighfueleconomyvehicle.Asshowninthefigure,ahighfueleconomyvehicleismuchmoreaffectedbytheauxiliaryloadthanaconventionalvehicle.Therefore,moreefficientthermalmanagementsystemsincludingVCSandCCSareessentialforHEV.

Figure1.Energyflowforvariousvehicleconfigurations.（A）ICE,theconventionalinternalcombustion,sparkignitionengine;（B）HICE,ahybridvehiclethatincludesanelectricmotorandparalleldrivetrainwhicheliminatesidlinglossandcapturessomeenergyofbraking[1].]

Figure2.Comparisonoffueleconomyimpactsofauxiliaryloadsbetweenaconventionalvehicleandahighfueleconomyvehicle[2]

AchievingefficientVCSandCCSforHEVsrequiresmeetingparticulardesign

challengesoftheVCSandCCS.ThedesignoftheVCSandCCSforHEVsisdifferentfromthoseforconventionalvehicles.VCSdesignforHEVsismuchmorecomplicatedthanthatofconventionalvehiclesbecausethepowertrainofHEVshasadditionalpowertraincomponents.Furthermore,theadditionalpowertraincomponentsareoperatedatdifferenttemperaturesandtheyareoperatedindependentlyoftheengineoperation.ThedesignofCCSforHEVsisalsodifferentfromthatofconventionalvehiclesbecausethetemperatureofthebatterypackinHEVsiscontrolledbytheCCS.Thus,theheatloadfortheCCSofHEVsismuchhigherthanthatfortheCCSofconventionalvehicles.Thus,thisisanotherchallengeforthedesignoftheVTMSforHEVs.

Asnotedabove,theseadditionalpowertraincomponentssuchasagenerator,drivemotors,alargebatterypack,andapowerbusrequireproperthermalmanagementtopreventthermalrunawayofthepowerelectronicsusedfortheelectricpowertraincomponents.Thus,thethermalmanagementofthepowerelectronicsandelectricmachinesisoneofthechallengesfortheHEVdevelopmentandvariousstudieshavebeenconducted[3-7].Generally,dedicatedVCSforthehybridcomponentsarerequiredasaresultoftheconsiderableheatrejectionsanddifferentcoolingrequirementsoftheelectriccomponents.InthecoolingsystemofHEVs,acoolingpumpdrivenbyanelectricmotor,ratherthanapumpdrivenbytheengine,isusedforthecoolingcircuitoftheelectricpowertraincomponentsbecausetheyneedcoolingevenwhentheengineisturnedoff.ThebenefitsofacontrollableelectricpumpoverthemechanicalpumpwerestudiedbyChoetal.[8]inthecaseofthecoolingsystemforamediumdutydieselengine.Theyusednumericalsimulationstoassessthefueleconomyandcoolingperformanceanditisfoundthattheusageofanelectricpumpinplaceofthemechanicalpumpcanreducepowerconsumptionbythepumpandpermitdownsizingoftheradiator.Inadditiontothosebenefits,theuseofanelectricpumpmakestheconfigurationofthecooingcircuitsinhybridvehiclesrelativelyflexibleintermsofgroupingcomponentsindifferentcircuits.However,thisflexibilityraisesanissueinoptimizingcoolingcircuitarchitecturebecauseofthecomplexityofthesystemandtheparasiticpowerconsumptionofthecoolingsystem.Theperformanceandpowerconsumptionofthecoolingsystemarealsoverysensitivetothepowertrainoperation.Thepowertrainoperationisdeterminedbythepowermanagementstrategy,whichchangesinresponsetodrivingconditionsofHEVs.Therefore,theeffectsofdrivingconditionsmustbeconsideredduringthedesignprocessofthecoolingsystem.Thus,inlightoftheseadditionalcomponents,designflexibility,andtheeffectsbyvehicledrivingcondition,itisclearthatthedesignoftheVCSforHEVsdemandsastrategicapproachcomparedwiththedesignoftheVCSforconventionalvehicles.

AnotherchallengeindesigningtheVTMSforHEVsismanagingthecabinheatloadgeneratedasaresultoftheplacementofthebatterypackinthepassengercompartment.InHEVs,thebatterypackislocatedonboardbecauseofitsloweroperatingtemperaturecomparedwithpowertraincomponents.Therefore,batterythermalmanagementsystemisapartoftheClimateControlSystem（CCS）becausethebatteryiscooledbyusingtheCCS.Thus,theloadontheCCSofHEVsishigherthanthatofconventionalvehiclesbecausethebatteryisthemajorheatsourceinthecabin.Inaddition,batterythermalmanagementisimportantforthehealthandlifeofthebattery.Althoughhightemperatureoperationisbetterforthebatteryperformanceduetoreducedbatterylossandreducedbatterythermalmanagementpower,hightemperatureoperationislimitedduetothebatterydurabilityandsafety.Figure3showsthetemperaturedependencyofthecyclelifeofLiionbattery.Ascanbeseeninthefigure,thebatterylifedropsdramaticallywhenthebatteryisoperatedathigherthan60°C.Thesamehappensatlowertemperature.Inextremecases,lithiumionbatterycanexplodebyachainreaction.Generally,thebatteryoperatingtemperatureislimitedlowerthan60°Cforthelithiumionandleadacidbattery[9-10].Accordingly,batterythermalmanagementassociatedwithclimatecontrolsystemisacriticalpartofvehiclethermalmanagementsystemdesignofHEVs.Therefore,acomprehensivevehiclethermalmanagementsystemanalysisincludingVCSandCCSisneededfortheHEVvehiclethermalmanagementsystemdesign.

Figure3.TemperaturedependencyofthelifecycleofLi-ionbattery[11].

Recognizingtheneedfortheefficientvehiclethermalmanagementsystem（VTMS）designforHEVs,manyresearchershavetriedtodealwiththeVTMSdesignforHEVsfromvariousview-points.BecauseofthecomplexityandthenecessityforthedesignflexibilityofthethermalmanagementsystemofHEVs,numericalmodelingcanbeanefficientwaytoassessvariousdesignconceptsandarchitecturesofthesystemduringtheearlystageofsystemdevelopmentcomparedwithexperimentsrelyingonexpensiveprototypevehicles.Tracietal.[12]demonstratedthatanumericalapproachcouldbesuccessfullyusedforthermalmanagementsystemdesignofHEVs.Theysimulatedacoolingsystemofanall-electriccombatvehiclethatusesadieselengineasaprimepowersourceandstoresthepowerinacentralenergystoragesystem.Theyconductedparametricstudiesontheeffectoftheambienttemperatureonthefanpowerconsumptionandtheeffectofthecoolanttemperatureonthesystemsize.ParkandJaura[13]usedacommercialsoftwarepackagetoanalyzetheunder-hoodthermalbehaviorofanHEVcoolingsystemandstudiedtheeffectoftheadditionalhardwareontheperformanceofcoolingsystem.Theyalsoinvestigatedtheeffectofanelectronicmodulecoolerontheconventionalcoolingsystem.Thesepreviousstudies,however,focusedonparametricstudiesanddidnotdealwiththearchitecturedesignofthevehiclethermalmanagementsystemconsideringthepowerconsumptionofthesystem.

TherealsohavebeenmanyeffortstoanalyzetheimpactoftheCCSontheHEV.BennionandThornton[6]comparedthethermalmanagementofadvancedpowertrainsusinganintegratedthermalmanagementsystemmodelandstudiedonthepeakheatloadoveratransientvehicledrivingcycletominimizethesizeofcoolingsystem.TheyalsostudiedthecasesinvolvingeffortstominimizethecoolingcircuitbyintegratinglowtemperaturecircuitswithhightemperaturecircuitsorA/Ccircuits.KimandPesaran[14]studiedbatterythermalmanagementofHEVfocusedonthebatterytemperaturedistributioninthebatterypack.Pesaran[15-16]studiedthebatterythermalmodelsandthevariousmethodsofbatterycoolinginHEVs.However,thesepreviousstudiesdidnotdealwiththebatterythermalmanagementintegratedwiththeA/Csystem,whichisapartofthevehiclethermalmanagementsystem.

Asintroducedabove,althoughHEVsneedmoreefficientVTMSthanconventio