畢業(yè)設(shè)計(jì)汽車外文翻譯（附帶中文原文）

The21stCenturyElectricCarMartinEberhardandMarcTarpenningTeslaMotorsInc.6October2006INTRODUCTIONAsassociatedwithenergyindependenceandenvironmentalissue,alternativefuelvehicle,especiallyElectricandHybridelectricvehiclehasbecomepartofthegovernmentpolicyallovertheworld.TheunitedStatemandatesastricterfueleconomystandard.Chinaissuedanewenergyvehiclepolicytoaccelerate&subsidizethedeploymentofelectricthisyearandsetagoalof500kfor2011.HongKongalsosetaclearvisionforEVapplicationinthenearfuture.Asfortheautoindustry,asilentgreenresolutionisundergosignificanttransformationaftergasolinepricerosesignificantlytoexceedUS$2levelandmarketdemandsforsuchvehicle.TheindustryintroducedmorefuelefficientHEVsandlesspollutedvehiclestothemarket.AsOilpricesurgedrapidlyduringthelastfewyears,thephenomenonhaspushedpureelectricvehicledevelopmentregainingtractionamongautomakersandgovernments.TheconsumermarkethasbroughtsignificantgaininalternativefuelvehicleaswellasHEVandelectricvehicles.AHEVstudyconductedbyPolk&CompanyindicatedanupwardtrendofmarketshareofHEVsalesinUnitedStateandWesternEurope.AnevenbiggershareofHEVandEVwerepredictedwhentheycombined.Infact,selectionofHEVmodelsfromOEMshavegrownfromtwo(Insight&Prius)in2000tomorethantwentiesastoday.SalesoftheHEVareinthefasttrackalongwithmorethan300,000HEVsoldin2007[2].FurtherknowncommitmentsofHEVandelectricvehiclefromOEMwillimprovetheHEVproductionevenmore.Addingplug-inandelectricvehicletothelineupwillstrengthenandacceleratethecurrentelectrificationtrend.ChevyVolt,thefirstplug-inhybrid,andabunchofplannedelectricvehiclessalutedforendconsumerintheNorthAmericawillleadtoaroundofnewenergyvehicleinthemarket.HISTORYOFELECTRICVEHICLEDEVELOPMENTTheelectriccar,oncethe“zero-emissions”darlingofenvironmentalists,issometimesmalignedasan“emissions-elsewhere”vehicle,sincetheelectricitytochargeitsbatteriesmustbegeneratedinelectricalgenerationplantsthatproduceemissions.Thisisareasonablepoint,butwemustthenaskhowmuchpollutionanelectriccarproducespermile–accountingforallemissions,startingfromthegasoroilwellwherethesourcefuelisextracted,allthewaytothefinalconsumptionofelectricitybythecar’smotor.Whenweworkthroughthenumbers,wefindthattheelectriccarissignificantlymoreefficientandpolluteslessthanallalternatives.Inthispaper,wewillinvestigatetheTeslaRoadster?,whichusescommoditylithium-ionbatteriesinsteadoflead-acidbatteriesornickel-metal-hydridebatteriesasmostelectriccarshaveused.Notonlydoesthislithium-ion–basedcarhaveextremelyhighwell-to-wheelenergyefficiencyandextremelylowwell-to-wheelemissions,italsohasastonishingperformanceandsuperiorconvenience.Lithiumionbatteriesarealotmoredifficulttousethanprevioustechnologies;thisisthereasonthattheyhavenotsofarbeenusedinelectriccars.TeslaMotorsisspendingalotofeffortmakingasafe,light,anddurablelithiumionbatterysystem.Overtime,Teslawillprobablyputtensofmillionsintopackandcellfeaturesandoptimization.However–asthispaperwillshow,theenergyandpowerdensityoflithiumionbatteriesmakethiseffortveryworthwhile.EnergyEfficiencyTocomputethewell-to-wheelenergyefficiencyofanycar,westartwiththeenergycontentofthesourcefuel(e.g.coal,crudeoilornaturalgas)asitcomesfromtheground.Wethentracktheenergycontentofthisfuelasitisconvertedtoitsfinalfuelproduct(e.g.gasolineorelectricity),subtractingtheenergyneededtotransportthefueltothecar.Finally,weusethefuelefficiencyofthecaritself(e.g.itsadvertisedmpg)tocompletetheequation.Allfuelscanbedescribedintermsoftheenergyperunitofmass.Inthispaper,wewillexpresstheenergycontentoffuelsintermsofmega-joulesperkilogram(MJ/kg).Well-to-wheelefficiencyisthenexpressedintermsofkilometersdrivenpermega-joule(km/MJ)ofsourcefuelconsumed–ahighernumberisbetter.GasolineCarsInthissection,wewillcalculatethewell-to-wheelenergyefficiencyofanormalgasoline-poweredcar.First,let’stakegasoline’senergycontent,whichis46.7MJ/kg,1or34.3MJ/l.2Second,weknowthatproductionofthegasanditstransportationtothegasstationisonaverage81.7%efficient,3meaningthat18.3%oftheenergycontentofthecrudeoilislosttoproductionandtransportation.Third,34.3MJ/l/81.7%=42MJ/l;42mega-joulesofcrudeoilareneededtoproduceoneliterofgasolineatthegaspump.Themostefficientordinarygasolinecarmadewasthe1993HondaCivicVX,whichwasEPA-ratedat51mpgforcombinedcityandhighwaydriving.4Convertingtometric,thiscarwasratedat21.7kilometersperliterofgasoline.Thus,itsefficiencyis21.7km/l/42MJ/l=0.52km/MJ.KeepinmindthattheHondaCivicVXgotabouttwicethegasmileageoftypicalcars–acarlikeaToyotaCamryisratedaround0.28km/MJ.5HybridCarsAllhybridcarsavailabletodayhavenoprovisiontochargetheirbatteriesexceptbyusingenergythatisultimatelygeneratedbytheirgasolineengines.Thismeansthattheymaybeconsidered,fromapollutionandenergyefficiencyperspective,tobenothingmorethansomewhatmoreefficientgasolinecars.IftheEPA-certifiedgasmileageforsuchacaris51mpg,thisisexactlythesameasanordinarygasolinecarthatgets51mpg.(Ifahybridcarcouldrechargeitsbatteriesbyplugginginwhenathome,andifitsbatteriesheldenoughchargeforameaningfuldrive,thiswouldnotbetrue.)Themostefficienthybridcaristhe2005HondaInsight,whichgets63mpgforcombinedcityandhighwaydriving.6UsingsimilarmathasweusedfortheCivicVXabove,theInsight’swell-to-wheelenergyefficiencyis0.64km/MJ.ThefamousToyotaPriusisEPA-ratedtoget55mpgincombinedcity-highwaydriving,foranenergyefficiencyof0.56km/MJ.7ElectricCarsEvenwithtiresandgearingoptimizedforperformance(ratherthatabsoluteefficiency),theTeslaRoadsteronlyconsumesabout110watt-hours(0.40mega-joules)ofelectricityfromthebatterytodriveakilometer,or2.53km/MJ.Theenergycycle(chargingandthendischarging)ofthelithium-ionbatteriesintheTeslaRoadsterisabout86%efficient.Thismeansthatforevery100mega-joulesofelectricityusedtochargesuchabattery,only86mega-joulesofelectricityareavailablefromthebatterytopowerthecar’smotor.Thus,the“electrical-outlet-to-wheel”energyefficiencyoftheTeslaRoadsteris2.53km/MJx86%=2.18km/MJ.Themostefficientwaytoproduceelectricityiswitha“combinedcycle”naturalgas-firedelectricgenerator.(Acombinedcyclegeneratorcombuststhegasinahigh-efficiencygasturbine,andusesthewasteheatofthisturbinetomakesteam,whichturnsasecondturbine–bothturbinesturningelectricgenerators.)ThebestofthesegeneratorstodayistheGeneralElectric“H-System”generator,whichis60%efficient,9whichmeansthat40%oftheenergycontentofthenaturalgasiswastedingeneration.Naturalgasrecoveryis97.5%efficient,andprocessingisalso97.5%efficient.10Electricityisthentransportedovertheelectricgrid,whichhasanaverageefficiencyof92%,11givingusa“well-to-electric-outlet”efficiencyof60%x92%x97.5%x97.5%=52.5%.Takingintoaccountthewell-to-electric-outletefficiencyofelectricityproductionandtheelectrical-outlet-to-wheelefficiencyoftheTeslaRoadster,thewell-to-wheelenergyefficiencyoftheTeslaRoadsteris2.18km/MJx52.5%=1.14km/MJ,ordoubletheefficiencyoftheToyotaPrius.12HydrogenFuel-CellCarsHydrogendoesnotexistinnatureexceptaspartofmorecomplexcompoundssuchasnaturalgas(CH4)orwater(H2O).Themostefficientwaytoproducelargequantitiesofhydrogentodayisbyreformingnaturalgas.Fornewplants,thewell-to-tankefficiencyofhydrogenproducedfromnaturalgas,includinggeneration,transportation,compression,isestimatedtobebetween52%and61%efficient.13TheupperlimitofefficiencyforaPEM(ProtonExchangeMembrane)fuelcellis50%14.Theoutputofthefuelcelliselectricityforturningadrivemotor,andwecanassumethesame2.53km/MJvehicleefficiencyaswiththeelectriccar.Withthesenumbers,wecancalculatethewell-to-wheelenergyefficiencyforourhydrogenfuel-cellcar:2.53km/MJx50%x61%=0.77km/MJ.Thisisimpressivewhencomparedtoagasolinecar,thoughitis32%worsethanourelectriccar.Butrealfuel-cellcarsdonotperformnearlythiswell.Severalcarcompanieshaveproducedasmallnumberofdemonstrationfuel-cellcars,andtheEPAhasratedtheefficiencyofsomeofthese.Thebestfuel-celldemonstrationcarmeasuredbytheEPAistheHondaFCX,whichgetsabout49milesperkilogramofhydrogen,15equalto80.5kilometersperkilogram.Weknowthattheenergycontentofhydrogenis141.9MJ/kg,16sowecancalculatethevehicleefficiencytobe80.5km/kg/141.9MJ/kg=0.57km/MJ.(Clearly,theHondafuelcellisnowherenearthetheoretical50%efficiencyassumedabove.)Whenwecalculatethewell-to-wheelenergyefficiencyofthisHondaexperimentalcar,weget0.57km/MJx61%=0.35km/MJ,notevenasgoodastheordinarydieselVolkswagenJetta,letalonethegasoline-poweredHondaCivicVXortheHondaInsighthybridcar.However,someproponentsofhydrogenfuelcellsarguethatitwouldbebettertoproducehydrogenthroughelectrolysisofwater.Thewell-to-tankefficiencyofhydrogenmadethroughelectrolysisisonlyabout22%,17andthewell-to-wheelenergyefficiencyofourtheoreticalfuel-cellcarwouldbe2.53km/MJx50%x22%=0.28km/MJ,andthewell-to-wheelenergyefficiencyoftheHondaFCXwouldbe0.57km/MJx22%=0.12km/MJ,evenlessefficientthanaPorscheTurbo.Evenwiththe$1.2billionU.S.governmentinitiativetoreduceU.S.dependenceonforeignoilbydevelopinghydrogen-poweredfuelcells,arecentreportbyapanelattheNationalAcademyofSciencesshowsthatAmericansshouldnotholdtheirbreathwaitingforthecarstoarriveinshowrooms."Inthebest-casescenario,thetransitiontoahydrogeneconomywouldtakemanydecades,andanyreductionsinoilimportsandcarbondioxideemissionsarelikelytobeminorduringthenext25years,"saidtheAcademy.1ComparisonThefollowingtableshowsthewell-to-wheelenergyefficiencyofseveraltypesofhigh-efficiencycars–includinganefficiencyestimateoftheTeslaRoadster–basedonthemeasuredperformanceprototypes.EmissionsBurningfuelproducesavarietyofemissions,includingsulfur,lead,unburnedhydrocarbons,carbondioxide,andwater.Throughtheyears,wehaveimprovedtheemissionsofbothcarsandpowerplantsbyreformulatingthefuelstoeliminatesulfurandmetals,andbyimprovingcombustionandpost-combustionscrubbingtoeliminateunburnedhydrocarbons.Intheend,anidealengineorpowerplantwillonlyemitcarbondioxideandwater.Waterisfine,butcarbondioxideisthegreenhousegasthatcannotbeavoided.Wecancomputethewell-to-wheelcarbondioxideemissionsforagivenvehicleinawaysimilartohowwecomputedenergyefficiency,sinceweknowthecarboncontentofthesourcefuel.Withperfectcombustion,allofthecarboninthesourcefuelwilleventuallybecomecarbondioxide.Assumingperfectcombustion,wecancalculatethe“CO2content”ofanysourcefuel.Crudeoilhasacarboncontentof19.9gramspermega-joule,andnaturalgashasacarboncontentof14.4gramspermega-joule.191gramofcarbonbecomes3.67gramsofCO2,sincetheatomicweightofcarbonis12,andoxygenis16.Therefore,theCO2contentofcrudeoilis73.0gramsofCO2permega-joule,andnaturalgashasaCO2contentof52.8gramsofCO2permega-joule.Withthesenumbers,wecancalculatethewell-to-wheelemissionsofthevariousvehicles,basedonthecarboncontentofthesourcefuelandtheenergyefficiencyofthevehicles:Again,theelectriccarshines–fromtheperspectiveofCO2emissions,itisthreetimesbetterthanthehybridcar,andnearlyfourtimesbetterthanthehydrogenfuel-cellcar.TheTrueMulti-FuelCarThebeautyofpoweringcarswithelectricityfromthegridisthatwecangeneratetheelectricityanywaywewantwithoutchangingthecars.Aswehaveseen,wecangenerateelectricitywithourchoiceoffossilfuels.Wecanalsousenuclearfuel,orwecangenerateitwithanyofanumberof“green”sources,suchashydroelectric,geothermal,wind,solar,orbiomass.Electricityistheuniversalcurrencyofenergy,andwealreadyhaveacomprehensivedistributionsystemforit.Proponentsofhydrogenfuel-cellcarsregularlycomparetheforecastedbestefficiencyofhydrogenproductionandconversion–infuturisticplantsandfuelcellsthathaveneverbeenbuilt–totheefficiencyoftheaverageexistingelectricgenerationplant–includingallthose25%to30%efficientpowerplantsthatwerebuiltinthe1950s.Thisisnotafaircomparison–ifwearewillingtobuildall-newhydrogenproductionplantstopowerahydrogencarfuture,thenweshouldbejustaswillingtobuildnewelectricgeneratorstopoweranelectriccarfuture.Wehaveassumed60%efficientbest-of-breedelectricgenerators,butnotscience-fictionelectricgenerators.However,naturalgasaccountsforonly14.9%20ofU.S.electricitygeneration;therestisamixofcoal,nuclear,andothers.Theaveragewell-to-outletefficiencyofU.S.electricgeneration,includingalltheold,inefficientpowerplants,isabout41%.21Withthisefficiency,ourelectriccarhasawell-to-wheelenergyefficiencyof0.83km/MJ,stillthemostefficientcarontheroad.Ofcourse,fuel-cellcarsarealsomulti-fuelcars,sincehydrogencanbeproducedfromwaterusingelectricityfromanysource.Butthisisaveryinefficientwaytouseelectricity.Considerthefollowingchart:Itisobviousthatwhenwestartwithelectricity(howeveritisproduced),itishardtobeatthe86%efficiencyofthecurrentlyavailablelithium-ionbatteriesandchargers.Evenwhenweassumeextremelyhighefficienciesforelectrolysis,compression,andthefuelcell,thefuel-cellcarrequiresmorethanthreetimesasmuchelectricityfromthegridtodrivethesamedistance.PerformanceThevisionofreplacingmanyofthecarsontheroadwithcleancommutervehicleshascausedmostproducersofelectriccarstobuildlow-endcarswithaslowapriceaspossible.Butevenifasolidargumentcouldbemadethatelectriccarswillultimatelybecheaperthanequivalentgasolinecars,theywillcertainlynotbecheaperuntiltheirsalesvolumeapproachesthatofatypicalgasolinecar–manythousandsperyearatleast.Untilanelectriccarmanufacturerachieveshighenoughsalestoapproachagasolinecarmanufacturer’svolumeefficiencies,electriccarswillneedtocompeteonothergroundsbesidesprice.Asidefromtheobviousemissionsadvantage,thereisanotherwaythatanelectriccarcanvastlyoutperformagasolinecar–inaword,torque.Agasolineenginehasverylittletorqueatlowrpm’sandonlydeliversreasonablehorsepowerinanarrowrpmrange.Ontheotherhand,anelectricmotorhashightorqueatzerorpm,anddeliversalmostconstanttorqueuptoabout6,000rpm,andcontinuestodeliverhighpowerbeyond13,500rpm.Thismeansthataperformanceelectriccarcanbeveryquickwithoutanytransmissionorclutch,andtheperformanceofthecarisavailabletoadriverwithoutspecialdrivingskills.Withagasolineengine,performancecomeswithabigpenalty–ifyouwantacarthathastheabilitytoacceleratequickly,youneedahigh-horsepowerengine,andyouwillgetpoorgasmileageevenwhenyouarenotdrivingithard.Ontheotherhand,doublingthehorsepowerofanelectricmotorimprovesefficiency.Itisthereforequiteeasytobuildanelectriccarthatisbothhighlyefficientandalsoveryquick.Atoneendofthespectrum,theelectriccarhashigherefficiencyandlowertotalemissionsthanthemostefficientcars.Attheotherendofthespectrum,theelectriccaracceleratesatleastaswellasthebestsportscars,butissixtimesasefficientandproducesone-tenththepollution.ThechartonthefollowingpagecomparestheTeslaRoadsterwithseveralhigh-performancecarsandwithseveralhigh-efficiencycars.Whenweplotwell-to-wheelenergyefficiencyagainstacceleration,almostallcarsfallalongacurvethatshowsexactlywhatweexpect:thebettertheperformance,theworsethemileage.Butthereisonecarthatiswayoffthecurve:theTeslaRoadster.Thiscarisclearlybasedonadisruptivetechnology–itsimultaneouslyoffersgreataccelerationandhighenergyefficiency.ConvenienceThefundamentaltrade-offinconveniencewithelectriccarsistheadvantageofstartingeverydaywitha“fulltank”(andnevervisitingagasstation)versusinconvenientrefuelingontheroad.Whileitiswonderfulnevertovisitagasstation,thiswouldbeabadtrade-offifthedrivingrangewastooshort.ElectriccarsliketheEV1gainednotorietyfortheirshort,60-miledrivingranges.22Incontrast,atypicalgasolinecarcangomorethan250milesonatankofgas.Themainreasonthatwewanttohave250-milerangeonourgasolinecarsisnotprimarilybecausewewanttodrive250milesinaday,butratherbecausewedon’twanttogotothegasstationeveryday–atankofgasshouldgoaboutaweek.Fromthisperspective,the60-milerangeoftheelectriccarmightbeenoughforacommutercar.But60milesisnotenoughforanythingbutthemostbasiccommute.Itisnotuncommontodrivesignificantlymorethan60milesinaday–oftenleavingdirectlyfromworkandwithoutanyplanningahead.(Forexample,adrivefromSiliconValleytothePebbleBeachgolfcourseisabout90mileseachdirection.)Makingmattersworse,themorefunacaristodrive,themoreitwillbedriven.Asportscarenthusiastmaylikelyfinda60-milerangetobeextremelyrestrictive.Lithium-ionbatteries(suchasthoseinmostlaptopcomputers)havethreetimestheamountofchargecapacityasthatoflead-acidbatteriesofthesamephysicalsize,and,atthesametime,weighsubstantiallyless.Additionally,lithium-ionbatterieswilllastwellover100,000miles,whileleadacidbatteriesneedtobereplacedaboutevery25,000miles.Theoriginallead-acidbasedGMEV1hadarangeofabout60miles.However,therangeofTesla’slithium-ionbasedRoadsterprototypehasarangeofmorethan250miles,(andweighed500poundsless).A250-milerangeismuchmoreacceptableevenforasportscarenthusiast.Theonlyshortfallofsuchanelectricsportscaristheinabilitytotakelongtrips,sincetherearen’tanyrechargingstationsalongthehighways,andsinceittakestimetochargebatteries.Untilwedevelopacharginginfrastructure(evenonethatonlyconsistsofsimple240-voltelectricaloutletsinconvenientplaces),oruntilbatterytechnologydoublesoncemoreincapacitytogiveusa500milerange,electriccarsarebestsuitedforlocaldriving–250milesfromhome,limitedbythebatterycharge.23Thisisprettymuchhowsportscarsaredrivenanyway:whenit’stimetotakealongtrip,takeyourothercar.Electriccarsaremechanicallymuchsimplerthanbothgasolinecarsandfuel-cellcars.Thereisnomotoroil,nofilters,nosparkplugs,nooxygensensors.Themotorhasonemovingpart,thereisnoclutch,andthetransmissionismuchsimpler.Duetoregenerativebraking,eventhefrictionbrakeswillencounterlittlewear.Theonlyservicethatawell-designedelectriccarwillneedforthefirst100,000milesistireserviceandinspection.BreakingtheCompromiseItisnowpossiblebuildanexceedinglyquicklithium-ionpoweredelectricsportscarthatlooksgood,handleswell,andisajoytodrive,atalowerpricethanmosthigh-performancesportscars.Andyet,thiscarwillbethemostfuel-efficientandleastpollutingcarontheroad.Youcanhaveitall.Notes1Well-to-WheelStudies,HeatingValues,andtheEnergyConservationPrinciple,29October2003,UlfBossel2DensityofGasolinefromPocketRef,3rdEdition,2002,ThomasGlover,Page6603ExhaustEmissionsFromNaturalGasVehiclesbyNyLund&Lawson,page27,andalsoWell-to-TankEnergyUseandGreenhouseGasEmissionsofTransportationFuels–NorthAmericanAnalysis,June2001,byGeneralMotorsCorporation,ArgonneNationalLaboratory,BP,ExxonMobil,andShell.Vol.3,Page594EPAmileagenumbersfrom5EPAmileagenumbersfrom6EPAmileagenumbersfrom7EPAmileagenumbersfrom8Forcomparison,thelead-acidbasedGMEV1electriccarwasratedat164Wh/mile,or102Wh/kmbytheUSDOEintheirEVAmericatests,formerlyat.9GeneralElectric"HSystem"Combinedcyclegenerator,modelMS7001H/9001H,asinstalledinCardiff,Wales,inTokyo,Japan,andinScriba,NewYork.10Well-to-TankEnergyUseandGreenhouseGasEmissionsofTransportationFuels–NorthAmericanAnalysis,June2001,byGeneralMotorsCorp.,ArgonneNationalLaboratory,BP,ExxonMobil,andShell.Vol.3,Page4211ibid,Page3312TheDepartmentofEnergyhasdefined“EquivalentPetroleumMileage”as82,049Watt-hourspergallon,whiledrivingtheelectricvehicleoverthesameurbanandhighwaydrivingschedulesasareusedtocomputetheEPAmileageforothercars,andtakingintoaccountchargingefficiency.(SeeCodeofFederalRegulations,Title10,Section474.3.)Thiscalculationwouldleadtothedubiousconclusionthatourelectricvehiclegets:82049Wh/gal/((110Wh/kmx1.6km/mi)/86%)=400milespergallon!13Well-to-TankEnergyUseandGreenhouseGasEmissionsofTransportationFuels–NorthAmericanAnalysis,June2001,byGeneralMotorsCorporation,ArgonneNationalLaboratory,BP,ExxonMobil,andShell.Vol.3,Page5914EfficiencyofHydrogenFuelCell,Diesel-SOFC-HybridandBatteryElectricVehicles,20Oct2003,UlfBossel15EPAmileagenumbersfrom16Well-to-WheelStudies,HeatingValues,andtheEnergyConservationPrinciple,29October2003,UlfBossel17Well-to-TankEnergyUseandGreenhouseGasEmissionsofTransportationFuels–NorthAmericanAnalysis,June2001,byGeneralMotorsCorp.,ArgonneNationalLaboratory,BP,ExxonMobil,andShell.Vol.3,Page5918Reuters,Feb4,2004,5:50PM1920Well-to-TankEnergyUseandGreenhouseGasEmissionsofTransportationFuels–NorthAmericanAnalysis,June2001,byGeneralMotorsCorp.,ArgonneNationalLaboratory,BP,ExxonMobil,andShell.Vol.3,Page4421ibid,Page5922GeneralMotorsEV1specificationsfromgmev/specs/specs.htm.Thissiteisnowdown,butspecificationscanstillbefoundat://carfolio/specifications/models/car/?car=107844&GM23MostRVcampsiteshavesuitable50-amp,240-voltoutlets,andcanbeusedforchargingontheroadtoday.See,forexample,koa.21世紀(jì)的電動(dòng)汽車馬丁·埃伯哈德和馬克·Tarpenning特斯拉汽車公司2006年10月6日引言由于能源獨(dú)立和環(huán)境問題，替代燃料車輛，特別是電力和混合動(dòng)力電動(dòng)汽車已經(jīng)成為相關(guān)政府政策的一部分，在世界各地。美國(guó)推廣了一項(xiàng)更嚴(yán)格的燃油經(jīng)濟(jì)標(biāo)準(zhǔn)。中國(guó)發(fā)布了一項(xiàng)新能源汽車補(bǔ)貼政策，以加速和部署今年的電力，并為2011年50萬(wàn)的目標(biāo)。香港還成立了電動(dòng)汽車在不久的將來(lái)應(yīng)用的清晰版本。至于汽車行業(yè)，無(wú)聲的綠色解決方案是經(jīng)過重大改造后的汽油價(jià)格大幅上漲超過2美元的水平，并為這些車輛的市場(chǎng)需求。業(yè)引進(jìn)更多的混合電動(dòng)汽車的燃油效率和減少污染車輛的市場(chǎng)。由于石油價(jià)格上漲在過去幾年里發(fā)展很快，這種現(xiàn)象已使純電動(dòng)汽車發(fā)展的汽車制造商和政府之間恢復(fù)牽引力。消費(fèi)市場(chǎng)帶來(lái)了替代燃料汽車以及混合動(dòng)力汽車和電動(dòng)汽車重大增益。HEV研究波爾卡公司進(jìn)行的市場(chǎng)調(diào)查顯示，如在西歐國(guó)家和美國(guó)混合動(dòng)力電動(dòng)汽車的銷售份額上升的趨勢(shì)。戊型肝炎病毒的一個(gè)更大的份額和EV進(jìn)行了預(yù)測(cè)時(shí)，他們結(jié)合起來(lái)。事實(shí)上，從原始設(shè)備制造商選擇混合動(dòng)力汽車模型已經(jīng)從2000年是只可選擇2款（本田的insight和豐田的Pries）到今天的可選擇20款之多。在混合動(dòng)力汽車的銷量在快速軌道以及更多的混合動(dòng)力汽車在2007年超過30萬(wàn)出售。進(jìn)一步已知的混合動(dòng)力汽車和電動(dòng)汽車原始設(shè)備制造商承諾將改善混合動(dòng)力汽車產(chǎn)量甚至更多。添加插件和電動(dòng)車的線路將進(jìn)一步加強(qiáng)和加快目前電氣化的趨勢(shì)。雪佛蘭伏特，第一款插入式混合動(dòng)力車，和一堆計(jì)劃（生產(chǎn)）電動(dòng)汽車（銷售商）為對(duì)北美北美最終消費(fèi)者表示敬意將在北美市場(chǎng)上引出一輪新能源汽車。電動(dòng)汽車,曾經(jīng)是“零排放”環(huán)保人士的寵兒，有時(shí)是被污蔑為“排放在其他地方“車輛，由于電力充電電池必須生成電子代植物產(chǎn)生的排放。這是一個(gè)合理的觀點(diǎn),但我們必須問電動(dòng)汽車每英里生產(chǎn)多少污染——占所有排放：它們天然氣或石油井從源燃料提取,一直到最終消費(fèi)的電力通過汽車的馬達(dá)。當(dāng)我們通過工作的數(shù)據(jù),我們發(fā)現(xiàn),電動(dòng)汽車是所有的備選方案中更有效和污染小的。在本文中,我們將調(diào)查,特斯拉跑車，它使用商業(yè)鋰離子電池代替鉛酸電池或鎳氫電池作為電動(dòng)汽車使用電池。這不僅基于鋰離子汽車有極高的能源效率和極低的排放,它也有驚人的性能和優(yōu)越的便利。鋰離子電池比以前使用技術(shù)有更多的困難;這是原因,他們迄今為止尚未被使用在電動(dòng)汽車上。特斯拉汽車公司投入很多努力制造一個(gè)安全,輕,和持久的鋰離子電池系統(tǒng)。隨著時(shí)間的推移,特斯拉將可能把數(shù)以百萬(wàn)計(jì)成的包和單元放入到系統(tǒng)中并使其優(yōu)化。然而,本文將證明,能量和功率密度的鋰離子電池使這個(gè)工作非常有價(jià)值的。能源效率為了計(jì)算任何汽車的能源效率,我們開始以能源來(lái)源豐富的燃料(如煤、原油或天然氣)，由于它來(lái)自地面。然后我們跟蹤能源豐富的燃料,因?yàn)樗罱K被轉(zhuǎn)換到燃料產(chǎn)品(如汽油或電),所需要的能量減去運(yùn)輸燃料的汽車。最后,我們使用汽車本身燃料效率的(例如其廣告mpg)完成方程。所有燃料可以描述成單位能量的質(zhì)量。在本文中,我們將能量豐富的燃料表達(dá)成兆焦耳每公斤(MJ/公斤)。效率被表達(dá)在每兆焦耳驅(qū)動(dòng)公里(公里/MJ)的燃料消耗——更高的數(shù)量是更好的。汽油汽車在本節(jié)中,我們將計(jì)算普通汽油驅(qū)動(dòng)的汽車的能源效率。首先,讓我們以汽油能源為例,汽油能量為46.7MJ/公斤1,1或34.3MJ/l2。其次,我們知道生產(chǎn)的氣體及其運(yùn)輸?shù)郊佑驼酒骄?1.7%的效率3,意味著18.3%的原油的能量是輸給了生產(chǎn)和運(yùn)輸。第三,34.3MJ/l/81.7%=42MJ/l;42兆焦耳的原油需要生產(chǎn)一公升的汽油。最有效的普通汽油車，這輛車是1993年本田CivicVX，這是EPA額定為51英里為城市和公路駕駛相結(jié)合4。轉(zhuǎn)換為公制為每公升汽油能跑21.7公里。因此，其效率為21.7公里/升/42MJ/L=0.52公里/MJ。請(qǐng)記住，本田CivicVX是有著兩倍左右的汽油里程的典型的汽車-一這車就如豐田凱美瑞被評(píng)為約0.28公里/MJ。5混合動(dòng)力汽車所有已經(jīng)上市，混合動(dòng)力汽車沒有支持能控制電池除了使用汽油發(fā)動(dòng)機(jī)的能量。這意味著，他們可能會(huì)認(rèn)為，從污染和能源效率的角度來(lái)看，無(wú)非某種程度上更高效的汽油車。如果這樣的車的EPA認(rèn)證的汽油里程為51英里，這就像行駛51英里的一個(gè)普通的汽油車一樣。（如果混合動(dòng)力汽車的充電電池，插入在家的時(shí)候，如果它的電池足夠的電荷進(jìn)行有意義的行駛，這不會(huì)是真的。）最高效的混合動(dòng)力汽車是2005年的本田Insight,得到每加侖63英里的城市和公路駕駛相結(jié)合。67電動(dòng)汽車即使輪胎和傳動(dòng)裝置的性能優(yōu)化(而不是絕對(duì)的效率),特斯拉跑車電流從電池來(lái)驅(qū)動(dòng)一公里,或2.53公里/兆焦只有大約消耗110瓦時(shí)(0.40兆焦耳)。8能源循環(huán)(充電然后放電)的鋰離子電池在特斯拉跑車大約是86%的效率。這意味著,每100個(gè)兆焦耳的電力用來(lái)充這樣的電池,電池中只有86兆焦耳的電力可以輸送給汽車的馬達(dá)。因此,泰斯拉跑車的“電力傳輸?shù)捷喿印钡哪茉葱适?.53公里/兆焦x86%=2.18公里/兆焦。最有效的方法來(lái)產(chǎn)生電能是利用“聯(lián)合循環(huán)”燃?xì)獍l(fā)電機(jī)。(一個(gè)聯(lián)合循環(huán)發(fā)電燃燒氣體在一個(gè)高效率的燃?xì)廨啓C(jī)和使用廢熱的渦輪產(chǎn)生蒸汽,它們則變成了第二渦輪,這兩個(gè)渦輪就變成發(fā)電機(jī)。)目前這些發(fā)電機(jī)最好的是通用電氣“h系統(tǒng)”發(fā)電機(jī),它有60%的效率9，這意味著40%的能量都浪費(fèi)在發(fā)電機(jī)上。天然氣回收效率是97.5%,和處理后也是97.5%的效率10。然后運(yùn)輸?shù)诫娏﹄娋W(wǎng)的平均效率為92%11，給我們一個(gè)“電力輸出”效率為60%*92%*97.5%*97.5%=52.5%?？紤]到特斯拉跑車有著好的電力傳輸?shù)碾娏ιa(chǎn)效率和電力傳輸?shù)杰囕喌男?以及好的傳輸?shù)杰囕喌哪茉葱?，這些效率是2.18公里/兆焦x52.5%=1.14公里/兆焦,或雙倍的豐田普銳斯的效率12。氫燃料電池汽車氫不存在在自然界除了存在更復(fù)雜的化合物如天然氣(甲烷)或水(H2O)中的一部分。目前最有效的方法來(lái)生產(chǎn)大量的氫是通過改革天然氣。對(duì)新植物,從天然氣中制氫有較好的效率的是灌裝法,包括生成、運(yùn)輸、壓縮,效率估計(jì)在52%和61%之間13。PEM(質(zhì)子交換膜）燃料電池的效率上限是50%14。燃料電池輸出的電力給驅(qū)動(dòng)馬達(dá),我們可以假設(shè)和電動(dòng)汽車有相同的2.53公里/兆焦效率的車輛。用這些數(shù)據(jù),我們可以計(jì)算出氫燃料電池汽車的能量效率:2.53公里/兆焦x50%*61%=0.77公里/兆焦。電動(dòng)汽車的這些數(shù)據(jù)和一輛汽油車相比是令人印象深刻的,盡管汽油車比我們的電動(dòng)汽車效率低32%。但真正的燃料電池