2013-Development-of-a-New-Two-Motor-Plug-In-Hybrid

INTRODUCTIONCompliancewithglobalstrengtheningofemissionregulationsisanurgentissuefortheautomobileindustry.Thefinalsolutionforthisrequirementshouldbetoputtingzero-emissionvehicles,suchasBEV(BatteryElectricVehicle)orFCEV(FuelCellElectricVehicle)intopracticaluse.However,theycouldnotbeasuitablereplacementofconventionalcarsbecauseoftheirlimiteddrivingrangeandhighercostduetocurrenttechnicallimitations.Therefore,HEV(HybridElectricVehicle)applicationhasbeenexpandinggloballyasoneofpracticalsolutions.Anewtwo-motorplug-inhybridsystemwhichrealizesbothenvironmentalfriendlinessofzero-emissionvehiclesandpracticalitiesofHEVsisdevelopedtosatisfythissituationandmainfeaturesarediscussedinthispaper.OVERALLCONFIGURATIONThemajorcomponentsofthenewtwo-motorplug-inhybridsystemareplacedinthevehicleasshowninFigure1.AnelectriccoupledCVT(e-CVT)isinstalledinthepositionofaconventionaltransmissionandutilizedincombinationwithanAtkinsoncycleengineoptimizedforHEVapplication.ThePCU(PowerControlUnit)ispositionedabovethee-CVTandcooledbyanindependentwatercoolingcircuitseparatedfromtheengine.Variousfunctionsincludinghigh-voltageinverters,VCU(VoltageControlUnit)andmotor/generatorECU(ElectricControlUnit)areintegratedinthePCU.IPU(IntelligentPowerUnit)isinstalledbehindtherearseatsandcooledbycoolingfanslocatedinthetrunkroom.ALi-ionbatteryspeciallydesignedforplug-inhybrid,aDC/DCconverter,ahigh-poweron-boardchargerandabatteryECUconstitutetheIPUasonepackage.Figure2showsastructureoftheIPU.2013-01-1476Published04/08/2013Copyright©2013SAEInternationaldoi:10.4271/2013-01-1476saealtpow.saejournals.orgDevelopmentofaNewTwo-MotorPlug-InHybridSystemNaritomoHiguchi,YoshihiroSunaga,MasashiTanakaandHirooShimadaHondaR&DCo.,Ltd.ABSTRACTAhighlyefficienttwo-motorplug-inhybridsystemisdevelopedtosatisfytheglobaldemandsofCO2reduction.Thissystemswitchesthreeoperationmodes,whatiscalled“EVDrive”,“HybridDrive”and“EngineDrive”,tomaximizefuelefficiencyaccordingtothedrivingconditionofthevehicle.Practicalplug-inEV(ElectricVehicle)capabilityisalsorealizedbyaddingahigh-poweron-boardchargerandahighcapacityLi-ionbatterytotheoriginalsystem.TheoutlinesofthesystemcomponentsincludinganewlydevelopedAtkinsoncycleengine,ahighlyefficientelectriccoupledCVT(ContinuouslyVariableTransmission)withbuilt-inmotorandgenerator,anintegratedPCU(PowerControlUnit)andanexclusivebatteryforplug-inHEV(HybridElectricVehicle)aredescribedinthispaper.Inadditiontotheswitchingofthreedrivingmodesandtheefficiencyimprovementofeachdevice,cooperativecontrolofthehybridsystemisintroduced.Byinstallingthissystemin2014Accordplug-inhybrid,superiorfueleconomyisachievedwithvaluesof46MPGinCS(ChargeSustaining)modeand115MPGe(MilesPerGallonequivalent)inCD(ChargeDepleting)mode.13milesofAER(AllElectricRange)isalsoachievedwhilemaintainingsufficientdrivingperformanceasamid-sizesedan.MPGeisaunitoffueleconomyforthealternatefuelvehiclessuchasplug-inhybridorelectricvehicles.Theratingsarecalculatedbyconvertingusedelectricenergyintoequivalentamountofgasoline.CITATION:Higuchi,N.,Sunaga,Y.,Tanaka,M.andShimada,H.,DevelopmentofaNewTwo-MotorPlug-InHybridSystem,SAEInt.J.Alt.Power.2(1):2013,doi:10.4271/2013-01-1476.____________________________________135DownloadedfromSAEInternationalbyChongqingUniversity,Sunday,January04,2015Figure1.OverallsystemconfigurationFigure2.IPU(IntelligentPowerUnit)POWERTRAINOverviewAnoverviewofthepowertrainisshowninFigure3andoperationmodesofthissystemareexplainedinTable1.Thissystemcanbeoperatedinthreeoperationmodesexplainedbelow.In“EVDrive”mode,theelectricmotorphysicallyconnectedtothedriveshaftpropelsthevehiclebyusingelectricenergystoredinthehighvoltagebattery.In“HybridDrive”mode,theelectricmotorisdrivenbyelectricenergygeneratedbythegeneratorusingoutputfromtheengine.In“EngineDrive”mode,theengine-driveclutchlocatedbetweentheengineandwheelsisengaged,andthevehicleisdirectlypropelledbytheengineoutput.Fuelefficiencyofalldrivingconditionsismaximizedbyswitchingthesethreedrivingmodesproperly.Figure3.HybridpowertrainTable1.OperationmodesFigure4.BlockdiagramofhybridsystemFigure4isablockdiagramofthissystem.ThepowertrainsystemofthisvehicleconsistsofanAtkinsoncycleengine,ane-CVTwithbuilt-inmotorandgenerator,aPCUandahigh-voltagebattery.ECUs,whichcontrolthesepowertraincomponents,realizecooperativecontroleachotherthroughtheon-boardcommunicationnetwork.Moreover,anoverallsystemconfigurationisdesignedforcooperativecontrolwithrelatedsystemssuchasanelectricservobrake,anelectricairconditionerandanelectricheaterHiguchietal/SAEInt.J.Alt.Power./Volume2,Issue1(May2013)136DownloadedfromSAEInternationalbyChongqingUniversity,Sunday,January04,2015tooptimizesystemefficiencyaccordingtothesituationofthevehicle.Theoutlinesofthepowertraincomponentsandrelatedsystemsaredescribedinthefollowingsections.AtkinsoncycleengineA2.0LDOHC(DoubleOverHeadCamshaft)engineforthistwo-motorhybridsystemisdevelopednewly.AtkinsoncycleandcooledEGR(ExhaustGasRecirculationsystem)areadoptedandthesetechnologiescombinewiththeVTEC(VariablevalveTimingandElectricControl)system.Thisengine