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Electric cars are backAboutAyEArAgo,theunitedStateswascomingoffagaso-linepriceshock,hybridelectricvehicleswerethestateoftheartinproduction-cartechnology,andso-calledplug-inhybridsweresomethingonlyafewgaragehackersandgreenextremistsdidforfun.theworld’slargestcarcompany,generalMotorsCorp.,waslockedinaboardroomfightwhileitsNorthAmericanproductswith-eredonthevine.

Ah,whatadifferenceayearmakes.today,thestateofthearthaspassedbeyondhybridstotechnolo-

giesthatseemeddeadorridiculouslyexoticevenayearago:pureelectric-drivecars,includingfuel-cellvehicles;andplug-inhybrids,whichgivetheoptionofchargingthehybrid’sbatteriesdirectlyfromawallsocket.Don’tlookforsuchcarsinshowroomsanytimesoon,butnoticethatsomeprettyspecificideasabouthowtheywillenterthemarketarestartingtoemerge.Andsomeofthoseideascomefromanunlikelysource:gMitself.

butfirst,arealitycheck.Nearly50millioncarsandlighttrucksweresoldbymajormanufacturersworldwidelastyear.Noneofthosevehicleswerepureelectrics,andonly350000—lessthan1percent—werehybridsofonesortoranother.by2025,saysPhilipgott,amarketforecasteratindustryanalystglobalInsight,12percentoflightvehiclessoldgloballywillbehybrids.Another12percent,hesays,willbediesels.

Fewanalystswillevenhazardaguessaboutwhenthefirstpureelectricswillshowupintheshowroomsofmajormanufacturers.butgMisclearlystrivingtobethecompanythatputsthemthere.theautogiantannouncedseveralconceptsandtestfleetslastyear,allbasedonacommonsetofcomponentsusingelectricmotorstopowerthewheels.

EvenasgMstruggledtoregainthehighgroundintech,ittookmorethanitsshareofpublicrelationshits.therewasthenewsthatitwillalmostcertainlyhavetocedetotoyotaitscrownastheworld’slargestautomaker,eitherthisyearornext.It’satitlegMhasheldfor70years.thecompanyshedmorethan30000employeesinNorthAmericalastyear(itpledgedtoreinvestsomeofthesavedcashintechnology).

ManyobserversremainskepticalofgM’sgoals,pointingtothethreedecadesthecompanyspentaggressivelybattlinganyandallregulationinthefieldsofsafety,emissions,andenergyusage,whilealitanyofgMinnovationslanguishedinlaboratories.therewasthecompany’sromancewithhydrogen,forexample,exemplifiedbyHy-wire,gM’s2002fuel-cellcar.CarspoweredbyhydrogenfuelcellsremainingM’svision,butthey’vebeenrecastasapieceofalargerstrategyinvolvingelectric-drivevehicles.

Severalothermanufacturershaveunveiledfuel-cellconceptcars,includingHondawithitslatestFCX,whichmadeourlistthisyear.Andthere’smorethanonewaytospinwheelswithhydrogen:bMWandMazdaeachreleasedroughly100produc-tionvehicleswiththeabilitytoburnhydrogenintheirinternal-combustionengines.

oneofthebiggestobstaclestohydrogen-poweredcarsisthelackofglobalhydrogenproductionanddistributioninfrastructure.buttheautoindustrywasjoltedbyincreasingspeculationlastyearthatasChinabuildsanetworkoffillingstations,itmightpossiblyusethemtodistributehydrogenaswellasgasoline—jump-startingtheglobalfuel-cellvehicleindustryinawayimpossibleinmoredevel-opedmarkets.

Suchastrategywouldassuagefears,asChinagoesmobile,ofavastgreenhousegasupsurge.theChinesemiddleclassisfindingoutwhatotherslearneddecadesago:carsarebulwarksofpersonalfreedomand,inthelargerpicture,ofeconomicgrowth.Fortunately,carstodayarecleaner,safer,morecapable,andmorereliablethanever.

thattrendwillgoon,probablyforever.Meanwhile,ourcollectivevisionofwhatconstitutesacarisevolvingwiththetechnologythatmakesitgo—andfeedsourfantasies. n

Ithaslithium-ionbatteriesandcomeswithachargingcable,justlikeyourcellphone.unlikeyourphone,however,itcangofromzeroto100kilometersperhourinlessthan4seconds,pinningyouagainstthebackofyourseatlikeafighterpilot.Andit’lldoitwithalotlessnoise—andforuS$70000less—thanaFerrariF430.

CreatedbyteslaMotors,aSiliconValleystart-upinSanCarlos,theteslaroadsterispoweredby6831mass-marketlithium-ionbatteriesandcostsabout$100000.Wantone?Fine,justputdown$75000nowandwaituntilsummer2008totakedelivery.

theteslawasengineeredbyEngland’sLotus,renownedforitssmall,lightsportscars.thecarweighsjust1100kilograms(2425pounds),nearlyathirdofthatbatteryweight.Withits185-kilowattmotor,ithasatopspeedof210km/h(130mph).

Aswithanypureelectriccar,thekeyparametersarethebatteries’rechargetime,energydensity,andusefullife.thepointofreference

2007 Roadster

A new kind of car from a Silicon Valley start-up

POWER PLANT n185-kWelectricmotor

TRANSMISSION n2-speedelectricallyactuatedmanualnrear-wheeldrive

CLAIMED RANGEn400km

MOREAmongthecar’sbuyersaretheusualeco-celebs.ActorsgeorgeClooneyandDennisHaysberthaveplunkeddowndeposits.

By John VoElckER

www.spectrum.ieee.org April2007|IEEESpectrum|NA35

A new kind of car from a Silicon Valley start-upistheonlyrecentelectricvehiclefromamajormanufacturer,thelate,lamentedgeneralMotorsEV1.WhentheEV1wasintroducedin1996,itranonlead-acidbatteries,hadamaximumrangeof95km(60miles),andtookupto12hourstorecharge.theteslausesthesamelithium-ionbatteriesfoundinlaptopsanddigitalcameras.theirenergydensitycanbeashighas160watt-hoursperkilogram—oratleastfourtimesthatoftypicallead-acidcells.Sotheteslahasa400-kmrangeand,bestofall,itcanrechargeinaslittleas3.5hours.

unresolvedatthemomentistheissueofbattery life.Laptopbatteriesusuallydon’tlast the 10 years required of major auto-

motivecomponents.Andteslahasindicateditexpectsitsbatterypack’spowertodegradeupto30percent inasfewasfiveyearsor200000km.Morethanadozencompaniesaretryingtodeveloplithium-ionbatteriesinsizesandpackagessuitableforautomotiveuse.Whenoneofthemsucceeds,thetacticoflashingtogethermanysmallcellsbolsteredbyinstrumentationtomonitorandaccommodatethepowerorthermalvariancesamongthemprobablywillend.

teslaMotors ishardly theonlynewEVmakerthesedays,thoughits$40millioninventurefundingputsitatthetopofthelist.globally,morethantwodozencompaniesare

offeringelectriccarsofalldifferentsorts,fromdrabecono-boxestosupercarsliketheteslaroadster.

Meanwhile,asofJanuary,teslahadsoldmorethan250cars—atidysumat$100000each.thefirstcarsaresupposedtobedeliv-eredinSeptember,ifcrash-testanalysesandotheru.S.government-certificationrequire-mentsgosmoothly.

teslaalsohasplans for a secondcar, asportyfour-seatsedancode-namedWhiteStar.thecompanyhopestolaunchthatcarby2010,atapriceof$50000.todoso,ithassetupanengineeringcenterinrochesterHills,Mich.,andplanstostaffitwithmorethan50engineers.n

By John VoElckER

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POWER PLANTn100-kWhydrogenfuelcell

CLAIMED FUEL EFFICIENCYn435kmfrom171litersofhydrogen,storedat350atmospheres

MOREHondaletjournaliststakethecaroutonthebankedtesttrackatitsr&DcenterinJapan,atspeedsupto140km/h(87mph).

»top 10 tech cars

POWER PLANT nVortecV8(displacementnotreleasedatpresstime)

TRANSMISSION ntwo-modehybridsystemntwo40-kWelectricmotorsnthreeplanetarygearsetsnAll-wheeldrive

CLAIMED FUEL EFFICIENCYn10.5L/100km(estimated)

MORE two-modehybridsystemisplannedforpickuptrucks,too.

gMC’syukon is a strapping2500kilogramsunloaded.Inotherwords,itain’tnoPrius.

And yet, yukons f it ted with gM’s newtwo-modehybrid systemuseessentially thesameprincipletoreduceenergyconsumptionastoyota’scelebrity-friendlyit-car.Anelectricdrivecanpowerthevehicle,byitselfortogetherwiththecombustionengine.thebatterythatpowersthemotorischargedbytheengineandalsothroughregenerativebraking.

beingasbigasitis,though,theyukonout-doesotherhybridsbyhavingtwoelectricdrivemotors,eachcapableof40kilowattssustained.Asinglemotorwithenoughtorquetomovesuchamasscouldn’tbeaccommodated insidethetruck.SogM’sengineers,who ledadesigneffort that later included engineers fromDaimlerChryslerandbMWaswell,usedapairofelectricmotors—asystemgMhadpreviouslyputintoproductionforitshybridtransitbuses.AsinthePrius,theyukon’smotorsareactuallymotor/generatorsthatcanproducetorquewhenfedwithelectricity—orviceversa.

thesizeofthesystemwasconstrainedbytheneedtofititintothesamespaceasthecompany’s6-speedautomatictransmission.Insideanalumi-numcasingarepackednotonlyfourfixedgearsbut(fromfronttorear)a“planetary”gearsetandelectricmotor,aclutch,asecondplanetarygearsetandmotor,andthenafinalclutchandgearset.Ineachplanetarygearset,acentralgear(the“sun”)isspunbytheengineorelectricmotor.thesunissurroundedbyplanetgearsthatarein

turnsurroundedbyaringgear,whichdrivesorisdrivenbyanothermotor.byvaryingthespeedatwhichtheplanetgearsspin,youalsochangethepowersplitbetweenthetorqueonthesunandthatontheringgear.beingabletosplitthepowerarbitrarilylikethatletsyouchanneljusttherightamountoftheengine’spowertothewheels;therestisdevotedtochargingthebatteries.

the“twomodes”ofgM’ssystemreferstothedifferentmixesofelectric-motorandcombustion-enginetorque.thefirst,orinput-split,modeisforlow-speedandlight-loadapplicationsfromlaunchthroughsecondgear.Asinexistingsingle-modehybridsystems,aplanetarygearsetsplitsenginepowerbetweenthewheelsandoneofthe

twoelectricmotors.Actingasagenerator,thismotorchargesthebattery,whichpowerstheothermotor,whichdrivesthewheelsaswell.Inthismode,theengine-controlsystemalternatesamongelectric-only,engine/electric,andengine-onlydrive,choosingtheoptionthatprovidesthebestperformancewiththelowestfuelconsump-tion.Fromrest,energyfromthe300-voltnickel-metal-hydridebatteriespowersthedrivemotor,whichisquicklysupplementedbytorquefromtheengine.

thesecond,orcompound-split,modeisforhighspeedsandheavyloads.Itprovideselectricassistinthethirdandfourthgears.Here,bothelectricmotorscanreceivetorquefromtheengine

2008 yukonTwo-Mode hybrid

A hybrid heavy hauler

FcX / concept

www.spectrum.ieee.org April2007|IEEESpectrum|NA37

Ifyouwantone,you’llhavetowaituntil2018atleast,Hondasays.butstill,itslatestFCX

conceptcartakeshydrogenfuel-cellpowertrains intoanew,sleeker realm. It ’sa

radical, stylishdeparture from thepreviousFCX’supright,slab-sided

hatchbackdesign.HondarevealeditsnewFCX

this past summer, around thesame time gM previewed itsChevroletSequelfuel-cellvehi-cle.but the twocarscouldn’tbemoredifferent.theSequelis a conventionally attractivesport-utilityvehicle,buttheFCX

isalow,four-door,five-passengersedan.Itwouldlookrightathome

ontheAutobahn,althoughitsmaxi-mumspeedof160kilometersperhour

(100milesperhour)wouldn’twinitmanyfriendsintheleftlane.

Itispoweredbythecompany’sthird-generation fuelcell,which is20percent

smallerand30percentlighter,andat100kilo-watts,14kilowattsmorepowerful.thenewV(forvertical)Flowstackstandsupright,andcanbepackagedinwhatusedtobecalleda

“transmissiontunnel”betweentheseats,low-eringthecenterofgravityanddoingawaywiththecharacteristictall,uprightdesignofmostpreviousfuel-cellvehicles.

Moreimportant,thedesignhelpseliminateoneofthebiggestobstaclestomainstreamuseoffuel-cellcars:thecostandcomplexityofthesystemsneededtoletthecellswithstandsub-freezingtemperatureswhenthey’renotrunning.Waterisaby-productofthereactionthatliber-ateselectricalenergyinafuelcell.butanywaterremaininginthecells’stack,wherethereactionoccurs,wouldcausedamageifitfrozethere.InHonda’svertical-flowdesign,gravityhelpsdrainthatwater—improvingperformanceandreducingthepowerneededtopumpthestackdryeverytimethecaristurnedoff.AccordingtoHonda,thesystemworkssowellthatthecarcanstartattemperaturesaslowas–20°C.

Witha smaller and lighter95-kWdrivemotor,thenewFCX’scompletepowersystemis180kilogramslighterandalmost40percentsmaller than its predecessor’s. Hydrogenisstored ina 171-liter tankatapressureof350atmospheres,givingthecararangeof435km(270miles),Hondasays.

HondaplanstoputthecarintoverylimitedproductioninJapannextyear.Still,it’sastepforward:virtuallyallfuel-cellcarsbuiltsofarhavegoneintocarefullymaintainedandshel-teredfleetsatutilitycompanies,forexample.butHondasaysitisconsideringleasingthecarsforuS$600or$700amonthtointerestedpri-vatecitizens,togetreal-worldfeedbackonhowthenewFCXdrives,rides,andperforms. n

can a fuel-cell car be sexy?

Standonastreetcornerinanymiddle-classsuburbinbrazilandwelloverhalfthecarswhizzingbywillbeflex-fuelvehiclescapa-bleofburningvariousmixturesofgasolineandethanol.

Amongbrazil’smanyflex-fuelcars,aver-sionoftheFiatSienastandsoutbecauseitrunsonanyblendofethanolandgasoline,andalsoonpurenaturalgasaswell.Itburnsthenaturalgasfirstbecauseit’sbrazil’scheap-estcarfuel.

theSiena stores the liquid fuel in a48-liter tankand thenaturalgas in two6.5-cubic-metercylindersinthetrunk.the1.4-Lenginehastwosetsofinjectors,oneforliquidfuelandasecondfornaturalgas.butthosearetheengine’sonlymajorhardwaremodifications.theengine-controlunit(ECu)isthesameastheoneonordinarySienas.Itjustrunsmoresophisticatedsoftware.

thecar’sexistingsensorsmeasuretheairflow intocylinders, theengine speedandload,andthespecificfuelbeingsenttotheengine.thedataarefedtotheECu,whichusesthemtooptimizefuelinjectionandsparktiming.Mostimportant,theECuusesdata fromthesensor thatmonitorsoxygenintheexhausttovarytheair-fuelmixcontinuouslyuntilthatsensordetectsnooxygenremainingintheexhaust,indicat-ingcompletecombustion. n

2007 Siena Tetrafuel

POWER PLANT n1.4-L4-cylindern59kW(gasoline,ethanol)n50kW(naturalgas)

TRANSMISSIONn5-speedmanual

CLAIMED FUEL EFFICIENCY n5.6to7.7L/100km(gasoline)n8.3to11.5L/100km(ethanol)n15to20km/m3(naturalgas)

MOREAt6270litersperhectare(670gallonsperacre),brazil’sproductionofethanolfromsugarcaneisnearlytwiceasefficientasu.S.productionfromcorn,accordingtotheEarthPolicyInstitute.

Research and translation for this segment was provided by Erico Guizzo.

Auto omnivoreandpowerfromthebattery.thesecondandthirdplanetarygearsetsnotonlysplittheenginepoweramongthedrivewheelsandtheelectricmotors,theycanmultiplyalltorquetodelivermaximumpowertothewheels.

Controllingitallaremicroprocessors.Infact,accordingtochiefengineertimCrewe,70percentof the total effort involved indesigningandtestingthesystemwenttowardcontrollogic.thatlogicanalyzeshundredsofinputsevery10milliseconds,includingvehicleload,engineoperations,batteryparameters,andthetemperaturesinthehigh-voltageelec-triccomponents.Dependingonvehiclespeedandpowerrequirements,onemotor-generatormayassisttheengine,orprovideregenerativebraking,withtheothershutdownforgreaterefficiency.orbothmotorscanprovideboostorbrakingsimultaneously.Andthecombina-tionofplanetarygearsetsandelectricmotorssmoothstheshiftingamongmodes,sothatenginespeedcanstayconstantevenasitvar-iestheelectricpowerdeliveredtothebatteryordrivewheels.

Whencoupledwithcylinderdeactivation,thetwo-modehybridsystemisexpectedtoimproveoverallfueleconomyby25percent,to10or11 litersper100kilometers(about22milespergallon).Forcomparison, thestandardgMCyukongets15to16L/100km(roughly15mpg)inthecityand11to12L/100km(20mpg)onthehighway,accordingtotheu.S.EnvironmentalProtectionAgency. n

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POWER PLANT n120-kWelectricmotornturbocharged1-L3-cylinderenginen53-kWgenerator:recharges16-kWhbatterypack

TRANSMISSION nNone;electricmotordrivesfrontwheels

MOREoneoftwocarsthisyearnamedforanelectricitypioneer,theotherbeingthetesla.

Volt / concept

POWER PLANT n125-kW1.4-Lturbochargedandsupercharged4-cylinder

TRANSMISSIONn6-speedmanualnFront-wheeldrive

CLAIMED FUEL EFFICIENCY n7.2L/100km

MOREAfterhistestrun,notoriouslyirritablereviewerJeremyClarksoncalleditoneofthef iveworstcarshehaseverdriven.

Powerful small-displacementengineshavealwaysbeenaEuropeanspecialty.buteveninEurope,anenginethatputsoutmorethan75kilowatts(100horsepower)perliterofdis-placementisnotable.Soonethatgets125kW(168hp)and240newtonmetersoftorquefrom1.4litersisquiteanachievement.throwinfuelconsumptionof7.2litersper100kilometers(33milespergallon), andyou’ve reallygotsomethingtocheerabout.

Solet’shearitforVolkswagen’sgolfgtwith thetSItwincharger engine.VW’sgoalwastoreducecarbondiox-ideemissionswhilemaintainingpower,torque,anddrivingcharacteristicsinanenginethatcouldbeproducedinhighvolumesforavarietyofvehicles.theresultingenginedeliversthehighestspecificpowerofanymass-produced4-cylinder,andthesametorqueasa2.3-Lenginewhileusing20percentlessfuel.

VW’sengineersoptedfortheconventionalapproachtomaximizingkilowattsperliter:startwithsmalldisplacement,andcoaxouteverypos-siblekilowatt.todothis,theirunusualtrickwastousebothasuperchargerandaturbocharger.Eachisessentiallyapumpthatpushesmoreairintothecylinder,allowingmorefueltobe

used,therebyincreasinganengine’spower.butasuperchargerisbasicallyanairpumpdrivenbygearsorabeltfromtheengine’scrankshaft,whileaturbochargerisasmallturbinespunbytheforceofescapingexhaustgases.

becauseit’sdrivenoffthecrankshaft,asuperchargercansupplyadditionalairtothecombustionprocessevenatlowenginespeed.ontheotherhand,aturbohasto“spoolup”toitsoperatingspeed,whichhappensonlywhentheengineisrunningfastenoughtogeneratesignificantexhaustpressuretospin it.thedelaybetweenadriveracceleratingandtheturboboostcomingon iscalled“turbo lag.”

VW’ssuperchargercompensatesforthatlag.below2400revolutionsperminute, the

superchargercanincreasethepressureoftheairprovidedtothecombustionprocessbyupto150kilopascals(about1.5atmospheres).underaccelerationfrom2400to3500rpm,thesuper-chargerstaysengagedwhiletheturbospoolsup.oncetheturbonearsitsmaximumboostof250kilopascals(2.5atmospheres),abypassflapswitchestheairsupplyfromthesuperchargertotheturbo.theintegrationofthetwoprovideshightorquefrom1750rpmto4500rpm. n

2007 Golf GT TSI

Recipe for fun: take a turbo and add a blower

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www.spectrum.ieee.org April2007|IEEESpectrum|NA39

Hybrid-electricvehicleshavebeenavailableforadecadenow.Andwithina fewyears,so-calledplug-inhybridswillofferbeefierbatteriesthatcanberechargedfromawallsocket,aswellasbythevehicle’sinternal-combustionengine.butbothvariantsarestilladaptedfromthesamedesignhandeddownduringacenturyofmechanicallydrivencars,inwhichtheengine’storqueistransferredmechanicallytothewheels.

Amoreradicaldesignistheserieshybridelectriccar—drivenbyoneormoreelectricmotorspoweredbybatteries that canberechargedbythecombustionengine.Intheseriesconfiguration,thecombustionenginecannotdrivethewheelsdirectly;itswitcheson,onlyasneeded,torunabackupgenera-torthatrechargesthebatteriesontripsthatexceedthecar’sall-electricrange.

theChevroletVolt,whichstoletheshowatDetroit ’sNorthAmerican InternationalAutoShowinJanuary,isthefirst-everserieshybridconcept vehicle shownbyamajorcarmaker.Its1-liter,3-cylinderturbochargedenginerunsanonboard53-kilowattgeneratorthatrechargesa16-kilowatt-hourlithium-ionbatterymadeupof804-voltcells.

thatbatterypowersthecarthrougha120-kWelectricmotordelivering320newtonmetersofpeaktorque,givinganall-electricrange estimated at 65 kilometers (about40miles).theplug-inrechargetimelikelywill

be6.5hoursorless.Andthe45-Lgasolinetankgivesalmost1000kmbetweenrefuelings.

onpaper,anyway.“Wedon’thaveabatterypackyet”fortheconcept,acknowledgestonyPosawatz,thevehiclelinedirector,whocon-firmedthatthecarshowninDetroitdoesn’tyet run—so its rangehasbeenestimatedfromlabtests.Amongotherqualificationsforautomotiveuse,lithium-ionbatterypacksmustlast10yearsorlongerthroughmorethan4000fullcharge-dischargecycles.

theVoltisthefirstofseveralconceptsthatareexpectedtousewhatgMcallsitsE-flexplatformforelectricallydrivenvehi-cles.Startingaround2010,gMplanstobuildavarietyofsubcompactvehiclesthesizeofanopelAstraonabasicarchitecturethataccommodatesE-flexcomponents.Somewillhavecombustionengines,somearelikelytobeparallelhybridswithplug-incapability,andothersmaybeserialhybridsliketheVolt.

gM’sannouncementthatitwouldproducecarsusingE-flexchangedtheVoltfromjustanothershinyconcepttoapossibleprecur-sorofatrulyradicalshiftindrivetechnology.DuringtheVolt’sunveiling,robertA.Lutz,gM’svicechairmanforproductdevelopment,wasclear:gMintendstosellcarspoweredbyelectricity.but,understandably,thecompanywon’tcommittoadatefordoingsountilitcangetsufficientlypowerfulanddurablelithium-ionbatteriesforautomotiveuse. n

GM’s vision of an electric-drive future

POWER PLANTn2.5-L181-kWturbochargedflat-4(orhorizontallyopposed4-cylinder)

TRANSMISSIONn5-speedautomaticnAll-wheeldrive

CLAIMED FUEL EFFICIENCY n9to11.8L/100km

MOREtestingthethreedifferentmodesofSubaru’sSI-Drivemayposeachallengeforgovernmentagencies.

SubaruhasalwaysbeenaJekyll-and-Hydecompany.Itssensibleall-wheel-drivestationwagonssit in thesameshowroomsas theirunrulyalter egos, suchas the fast, road-huggingImprezaWrXsedans,developedovermanyyearsofpunishingoff-roadrallies.

NowSubaruhas introduced technologytoletdriverschoose—sensibleorwicked?—bytwistingadialontheconsole.theSubaruIntelligentDrive(SI-Drive)sys-temletsdriversselectoneofthreemodes:Intelligent,Sport,orSportSharp.Itcomesstandardonthree2007models—oneofthemtheoutback2.5Xtwithautomatictransmission—andmoreareduenextyear.

theturbocharged2.5-literdouble-overhead-camengineinthe2.5Xt—inwhichthecylindersarehorizontallyopposed,likeaPorsche’s,tolowerthecenterofgravity—produces181kilowatts(243horsepower)andarousing327newtonmeters(241foot-pounds)oftorque.

AsyouchangeSI-Drivemodes,thesystem’scontrolsoftwarerevisessettingsfortheenginecontrol,automatic-transmissionshiftpoints,andthrottleresponse.InIntelligentmode,thesystemlimitsenginetorqueto309Nm,therebycuttingmaximumpowerbyroughly20percent.

Italsomakesthrottleresponsesmootherandmoregradual,improvingthefuelmileagebyupto10percent,Subarusays.

theSportmodesharpensthrottleresponsetofavoraccelerationandpoweroverfueleffi-ciency.thismodeisbestforfreewayandsubur-bandrivingandinhillyterrain,Subarusays.

theSportSharpmodeemphasizesinstan-taneouspowerdelivery.It’susefulforpassing.remappedshiftpointsholdthecarinitslowergearslonger,improvingaccelerationbymorethan50percent comparedwith Intelligentmode,Subarusays,andmimickingthewild-

childbehavioroftheWrX.the ideaofasingleenginewithmultiple

personalitieshadlongbeenthedreamoftoshioMasuda,Subaru’sprojectgeneralmanagerfortheLegacyoutbackline.Despiteskepticismthatsuchasystemwaspossible,oneofhisengineersbuiltaprototypeofwhatwouldbecometheSI-Driveandinstalleditinatest“mule.”thatcargraduallywonmanagementovertotheidea.

theteam’schallengelayinthefactthatofferingthreeperformanceprofilesrequiredthreetimesasmuchsoftwaredevelopmentandtesting. n

2007 outback 2.5XT

A sensible car acquires multiple personalities

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POWER PLANT n4.2-L309-kWV8

TRANSMISSIONn6-speedmanualnAll-wheeldrive

CLAIMED FUEL EFFICIENCY n12to17L/100km(14to20mpg),accordingtoCar and Driver

MOREHoldingdownboththeaccel-eratorandbrakeactivatestheoptionalautomatic’sLaunchControlmode,whichrevstheengineforthebesttractionandquickestacceleration.

POWER PLANT nNinedifferentenginesavailable,from120to270kW,including…n4-and6-cylinderin-linedieselsngasolinein-line6orV8

TRANSMISSIONSn6-speedmanualorautomaticnrear-orall-wheeldrive

CLAIMED FUEL EFFICIENCY n6.1to10.9L/100km

MOREtoreduceengineloads,bMWplanstointroducemoreelectricaccessorydrives.

2008 5-SeriesFor40years,engineersfromthebavarianMotorWorkshaveingeniouslyappliedtech-nologytothepursuitofasinglegoal:superbhandlingandperformance.butnowadays,notevenbMWcanignorecallsforcarsthatconsumeless,emit less,andtreadmoregentlyontheplanet.

the company has not announced ahybrid,thoughithaspartneredwithgMandDaimlerChrysler intheirtwo-modehybrid project [see “2008gMCyukontwo-Mode Hybr id”]. And now, on i tsrevised5-Seriessportssedans,bMWhasintroducedregenerativebraking—thefirsttimesuchasystemhasbeenusedonanonhybridcar.

the company’sbrakeEnergyregen-erationsystemgrewoutofanintelligentalternatorcontrolproject shownat lastyear’sParisAutoShow.thecoreideaistochangethetimesatwhichthealternatorchargesthebattery.

In a conventional car, the alternatorgeneratespowercontinuously,regardlessofother loadson theengine.but in thenew5-Seriescars,itisengagedtogener-atepoweronlywhenthecardecelerates.Atothertimes,whenthecariscruisingoraccelerating, itmerely freewheels.Withthealternatorno longersappingpower—aphenomenonknownasalternatordrag—

theengineneedstoworkslightlylesshardtomovethecar,cuttingfuelconsumption.thealternatoritselfhasnotchanged;bMWhassimplyinsertedanelectronicallycon-trolledclutchthatengagestoletitchargeonlywhenthecardecelerates.

thepowertodriveallthecar’selectriccomponents—asmuchas3.5kilowattsinthe average midsize car these days—issuppliedbyasomewhatmorepowerfulbattery.bMWwon’treleaseexactfigures,but it does say that it uses glass-mattechnology,whichseparatesthebattery’splateswithsaturatedabsorbentglass—boronsilicate—ratherthantheusualgelorliquidelectrolyte.theacidelectrolyteis held in themicrofibers between lay-ersoflead,improvingitsenergystorageduringfrequentcharge/dischargecycles,comparedwith standard lead-acidbat-teries.thoseordinarybatteriesconvertupto20percentofelectricalenergytoheatduringcharging,againstaslittleas4percentforglass-matdesigns.

Alternatordragisfoundinalmosteveryvehiclesoldtoday,soitsimpactmayseeminsignificant.but in theEuropeanuniondrivingcycle,whichisusedtomeasurefuelconsumptionforcarssoldwithinthatmarket,bMW’srevisedalternatorsystemreducedenergyconsumptionbyroughly3percent.n

Regenerative braking in a nonhybrid

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»top 10 tech cars

2008 R8

www.spectrum.ieee.org April2007|IEEESpectrum|NA41

ther8,Audi’sfirstexcursionintosupercarter-ritory,isprojectedtocostroughlyuS$130000whenithitsshowroomsthisyear.Ifthecurrentcropofstartersupercarsleavesyouunder-whelmed,yourshipmaybeabouttocomein.

ther8 isstuffedwithadvanced tech-nology,includinganaluminumspaceframe,adirect-injectionmidmountedV8,anda465-watt12-speakersoundsystem.Italso

hasshockabsorbersfilledwithfluidwhoseviscosityisvariedelectromagnetically,asintheCadillacXLrandSrX.

Allthosetechnologieshaveappearedinothercars,butnotalltogetherinonecar.Andthestylish,two-seatr8hassomethingthatsetsitapartinitscat-egory: light-emittingdiodesfor itsdaytimerunninglights.

LEDs of fer many advantagesasautomotivelamps,includinglowpowerandlonglife.theautomotive-lightingcompanyHellaquotes just10WforapairofLEDrunninglights,againstasmuchas150Wforstandard,

incandescentones.LEDsalsolastupto 50000hours—which translates to

100yearsofheadlightuseforanaveragecar.Andthey’resmallenoughtogivestyl-istsgreatfreedomoverfront-enddesign:designerscanclusterorscattersingleLEDlampsastheirsketchesrequire.

theonlyproblemiscost:upto$1000perpairifyouhavetoreplacethem.that’sroughly 10 t imes as much as the high-intensitydischarge lamps,whichcastabluishlight,usedonupscalecarstoday.Soforthemoment,LEDrunninglightsarelim-itedtojustafewhigh-endAudis:ther8andtheA8,S6,andS8.theracyr8,however,goesitssiblingsonebetterbyalsousingLEDstoilluminateits4.2-liter,309-kilowatt,high-revvingV8,whichisvisiblethroughawindowbehindtheseats.

ther8’slightsareproducedbyosramoptoSemiconductors, inSanJose.Eachrunninglamphas12separateLEDspotlightsarrangedinasinuouscurveunderthepodcontainingthehighbeamandturnsignal.Eachof theLEDsprovides 18 lumensat140milliamperes.

Meanwhile,AudiandLexusarecompetingtobethefirsttouseLEDsasheadlightsinapro-ductioncar.Lexusprobablywillwintherace,asitsLS600h—theultraluxurioushybrid-electricflagshipoftheLSline—isexpectedtohitshow-roomsanydaynow.theLexusdesignersstayedwithaconventionalheadlightshape—whichholdshigh-intensitydischargelampsinotherLSmodels(itwasshapedtoevokebaccaratcrystal).butAudipromisestoofferfullLEDheadlampsasanoptionforther8bytheendofthisyear. n

lED lights hit the road

POWER PLANT n2.4-L,2.7-L,or3.5-L

TRANSMISSIONn4-or6-speedautomaticn Front-wheeldrive

CLAIMED FUEL EFFICIENCYn8.7L/100km(combined,2.4-Lengine)

MOREMygigletsyouripCDsontoitsharddrive,butitwon’tletyoutransfertheMP3filestoanyexternaldevice.

Ifyou’veboughtanewcarrecently,chancesarethatitcanaccommodatemostoftheentertainmentmedia,formats,andcompres-sionalgorithmsyouprobablynowenjoy:AM,FM,andsatelliteradio;CD;DVD;MP3.butthechallengeofaccessingallthoseoptionsmayhaveleftyouresignedlylisteningtothedroneofnewsradio.

Chr ys ler fee ls your pa in. A new,uS$1700option on this year’sSebringsedanbundlesplayersforallthosemedia,plusacellphoneandnavigationsystem,into

asingledash-mountedentertainmentsetupcalledMygig.thesystem,developedwithstereomakerHarman/kardon,featuresasingle,consistentuserinterfacetooper-atethemall.

IntheMygig–equippedSebring,thediscplayercanplaymusicorshowmov-iestobackseatpassengersfroma7-inchdisplayattherearoftheconsolebetweenthefrontseatsor—ifthecarisparked—ona 6.5-inch in-dash display. the music,video,andnavigationfunctionscanallbe

controlledbyvoicecommands(inEnglish,Spanish,orFrench)or througha touchscreen.thesystemintegratesbluetoothhands-free mobile call ing, and it canrecordvoicememos.

theheartoftheMygigsystemisitsruggedizedharddrivethatholdsnaviga-tiondataandupto1600MP3orWindowsMediaAudiofiles,aswellaseightphotosandupto32address-booknames. It isoneof thefirstcar-basedsystemsthatletsyou ripCD tracks intoMP3 format

andstore themontheharddrive.MP3-savvyreadersmaywonderhowthesystem,withoutanInternetconnection,canfetchtheartist,title,andothertrackinforma-tionforaCD.gladyouasked. Includedwithin thesystem’s 1gbofsoftware isthegracenote lookupengine to locateinformationforroughlyamillionCDsthatgracenotebelievesNorthAmericanusersmayplay.Chryslerhadn’tdecidedatpresstimewhethertochargeusersforquarterlyupdatesatthedealer. n

2007 Sebring

nav system + DVD player + iPod + phone + hard drive = integration

JoHNVoELCkErhaswrittenaboutautomotivetechnologyandothertopicsfor20years.Hecoveredsoftwareandmicroprocessordesignfor IEEE Spectrumfrom1985to1990.

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