All Wheel Drive Energy Efficiency

AllWheelDriveEnergyEfficiencyDr.VladimirV.VantsevichLawrenceTechnologicalUniversityVoice:(248)204–2577E-mail:[e-mail]&Manufacturing,Inc.Voice:(248)844–6323E-mail:[e-mail]22008SAEAWDSymposiumPresentationOutline„Background–Energylossandefficiencymeasurement„Allwheeldrive,kinematicdiscrepancy,andlongitudinalslip„Tireeffects„Efficiencyeffectofthedriveline„Quantitativeevaluationofefficiency„Evaluationofvehiclearchitectures„Conclusion32008SAEAWDSymposiumWhyarewediscussingthis?„FuelcostandeffectontheAutoindustry„WhatisthenatureofpowerlossinAWDvehicles?42008SAEAWDSymposiumEnergyLossinaVehicleSource:UnitedStatesDepartmentofEnergy,{TheNationalEnergyModelingSystem(NEMS){UnitedStatesDepartmentofEnergy{Assessandpredictimpactofplanningassumptionsandproposedpolicies{Transportationmodulepredictsdemandforvehiclefuelefficiencybasedonenergycostandincomeusingcost/benefitcalculationandfuelsavingspredictionsforvarioustechnologies{Doesnotpredictindividualvehicleefficiency{VISION{ArgonneNationalLaboratory{What-ifenergyusebasedonfleetlongevity,alternativefueluse,andimplementationoffuel-savingtechnology62008SAEAWDSymposiumEfficiencyMeasurementOverview{ADVISOR{AVL(originallyNationalRenewableEnergyLaboratory){UsedinbothPartnershipforaNewGenerationVehicles(PNGV)andFreedomCarinitiatives{ADVISOR2004models2WDandAWD–nofurtherinformationavailable{RAPTOR{SouthwestResearchInstitute{What-ifenergyusebasedonfleetlongevity,alternativefueluse,andimplementationoffuel-savingtechnology72008SAEAWDSymposiumEfficiencyMeasurementOverview{PowertrainSystemAnalysisToolkit(PSAT){ArgonneNationalLaboratory{Primarilypowertrainanalysis{Implementswheelfrictionasaportionofthemodel{CarSim{MechanicalSimulationCorporation{Full3Dvehicledynamicsmodel{Efficiencyofdrivelinecomponentsisdefined,butnooverallenergyefficiencyofthevehicle82008SAEAWDSymposiumEfficiencyMeasurementOverviewCountry/RegionTypeMeasureStructureTestMethodImplementationUnitedStatesFuelmpgCarsandLightTrucksU.S.CAFÉMandatoryEuropeanUnionOveralllight-dutyfleetEUNEDCVoluntaryJapanFuelWeightbasedJapan10-15MandatoryChinaFuelWeightbasedEUNEDCMandatoryCaliforniaGHGCar/LDT1andLDT2U.S.CAFÉMandatoryCanadaFuelCarsandLightTrucksU.S.CAFÉVoluntaryAustraliaFuelOveralllight-dutyfleetEUNEDCVoluntaryTaiwan,SouthKoreaFuelEnginesizeU.S.CAFÉMandatorykmgLkmLkmkmL100kmL100kmL100mileg2COSource:“ComparisonofPassengerVehicleFuelEconomyandGreenhouseGasEmissionStandardsaroundtheWorld”,FengAnandAmandaSauer,PewCenteronGlobalClimateChange,200492008SAEAWDSymposiumEfficiencyMeasurementOverview{Regulatorytestprocedurestakeplaceon2WDdynamometers{PotentialproblemforAWDvehicles,includinghybridsK.-I.Shimizu,M.Nihei,andT.Okamoto.Fuelconsumptiontestmethodfor4WDHEVs-onanecessityofdoubleaxischassisdynamometertest.TechnicalReport06A0853604,JSAE,2006.L.Slezak.Advancedvehicletechnologyanalysisandevaluationactivities.Technicalreport,U.S.DepartmentofEnergy,OfficeofFreedomCAR&VehicleTechnologies,2004.{LH/RHrollersarecoupled{DifferentiationnotaccountedforUnitedStatesGovernment.Codeoffederalregulations86.108-00.GovernmentPrintingOffice,2007.J.Ivens.Officialfueleconomytestingsomepracticalaspectsofdynamometermatchingofthevehicleroadload.TechnicalReport910038,SAEInternational,1991.{Effectoflateraltorquedistribution102008SAEAWDSymposiumAllWheelDrive–WheelModes1.DrivenMode2.FreeMode3.DriveMode4.NeutralMode5.BrakingMode112008SAEAWDSymposiumTireLongitudinalSlipandKinematicDiscrepancy00wwxwwrVrsωωδ−=LongitudinalSlip0wwxsrVδωLongitudinalSlipRotationalvelocityofthewheelRollingradiusofthetireintheDrivenMode(notorqueapplied)Actualvehiclevelocity122008SAEAWDSymposiumPowerLossduetoSlipSlip(extradeformationoftires)requiresadditionalpower,whichislost.foronewheel–4xforAllWheelDrive.Powerlossduetoslipdependsonthedriveline,becausethedrivelinedistributespowerbetweenthewheels.Therefore,ifslipischanged,theefficiencyischanged.δδsVFPtx=132008SAEAWDSymposiumTireLongitudinalSlipandKinematicDiscrepancyInastraightline,tiωωωωωω=⇒=⇒=However,0102wwrr≠002121120221ttwwrutwVVrurumVru−−==KinematicDiscrepancyWheeltheoreticalvelocity142008SAEAWDSymposiumTireLongitudinalSlipandKinematicDiscrepancy102201102urururm−=2'''1'''2'''1()()11xgixgitrixxixiiiiRRFFssδδη==∑∑+=+−−∑∑==⎟⎠⎞⎜⎝⎛−+−⎟⎠⎞⎜⎝⎛−+−−=21''''''21'''''''''11111iixiixiiiixiiixisFsFssFssFδδδδδδδη2111russmδδ−=−m2121uurrmwwruKinematicDiscrepancyRollingradiusofthefrontwheelRollingradiusoftherearwheelEffectivegearratiotothefrontwheelEffectivegearratiototherearwheel00152008SAEAWDSymposiumEffectofDynamicWeightTransfer0100020003000400050006000700080003303353403453503553603653700.12MPawp=0.18MPawp=0.24MPawp=0.30MPawp=Normalload,N