Development-SPORT-HYBRID-i-MMD-Control-System-2014

−33−DevelopmentofSPORTHYBRIDi-MMDControlSystemfor2014ModelYearAccord1.IntroductionDemandsareincreasingfurtherontheautomotiveindustrytoreducetheenvironmentalload,suchasbyreducingCO2emissions.TheIntegratedMotorAssist(IMA)system,whichislighterinweightandmorecompact,hasbeenproposedasonemethodforaddressingthisissue.Inaddition,zeroemissionsystemssuchasfuelcellEVsystemsandbatteryEVsystemshavealsobeenproposed.Enhancementssuchasevenhigherhybridsystemefficiencyandlongerzeroemissioncruisingrangesareurgentlyneededtofurtherreducetheenvironmentalloadinthefuture.Anewtwo-motorhybridsystemcalledSPORTHYBRIDIntelligentMulti-ModeDrive(SPORTHYBRIDi-MMD)wasdevelopedtomeetthesedemands(1).Thishybridsystemfeatureshigherefficiencythanprevioushybridsystems,andalsoprovidespowerperformanceenablinguseinmid-sizesedans.Inaddition,thissystemalsoincreasedthezeroemissioncruisingrangeoftheSPORTHYBRIDi-MMDPlug-inthatisequippedwithalarge-capacitybatteryandaplug-inchargingfunction.Thispaperdescribesthegoalsandfeaturesofthenewlydevelopedtwo-motorhybridsystemusingtheSPORTHYBRIDi-MMDPlug-inasanexample.Inaddition,thispaperalsodiscussesthecontrolsystemthatcontributedtoincreasingefficiencyandsecuringvehiclereliability,andtheperformanceachievedbyanactualvehicle.2.DevelopmentGoalsThepreviousIMAsystemmadeuseofthecharacteristicsofalightweightandcompacthybridsystemtoachieveenhancedfueleconomymainlyincompactcars.However,similarenhancementsinfueleconomyarealsoneededformid-sizesedansandlargerclassestoreducetheenvironmentalloadinthefuture.Therefore,thetwo-motorhybridsystemSPORTHYBRIDi-MMDwasnewlydevelopedwiththeaimofhighefficiency.ThissystemswitchesthethreemodesofEVdrive,HybriddriveandEnginedriveaccordingtothedrivingconditions,andhasthefollowingfeaturescomparedtotheIMAsystem.(1)ExpandedEVdrivingrangeandhigherefficiency(2)Expandedareaenablinghighlyefficientengineoperation(3)MoreefficientrecoveryofdecelerationenergyAsaresult,itisthoughtthatthissystemcanachievegoodfueleconomy.However,thesystemconfigurationislargerthanthatoftheIMAsystem,andcoordinatedoperationisneededtomaintainsufficientdrivingperformancewhileobservingthevariousconstraintsforsecuringreliability.Therefore,acontrolsystemwasdevelopedthatsimultaneouslyrealizesbothfueleconomyanddrivingperformancebyperformingtheappropriatecontrolforthesysteminaccordancewithvariousenvironmentalanddrivingconditions.DevelopmentofSPORTHYBRIDi-MMDControlSystemfor2014ModelYearAccordHirohitoIDE*YoshihiroSUNAGA*NaritomoHIGUCHI*ABSTRACTAhighlyefficienttwo-motorhybridsystemnamedSPORTHYBRIDIntelligentMulti-ModeDrivewasdevelopedandmountedinthe2014modelyearAccordtomeetglobaldemandsforCO2reduction.Thecontrolsystemswitchesthethreedrivemodesof“EVdrive,”“Hybriddrive”and“Enginedrive”accordingtothedrivingconditions.Togetherwithhybridization,thishelpedtoenhancefueleconomyby39%.Inaddition,cooperativecontrolbetweencomponentswasdevelopedthatsupportsthelargesystemconfiguration,andhelpedtoachievebothreliabilityanddrivingperformance.InstallationofthissystemandcontroltechnologyinanAccordplug-inhybridachievedanEVdrivingrangeof13milesandfueleconomyof115MPGe(ChargeDepletingmode)and46mpg(ChargeSustainingmode).Furthermore,sufficientdrivingperformancewasalsomaintainedwhileobservingtheconstraintsrequiredtosecurereliability.Introductionofnewtechnologies*AutomobileR&DCenter−34−HondaR&DTechnicalReviewOctober2013PowerVehiclespeed/SOCTimeVehiclespeedSOCEnginerunflagVehiclepowerTimeCDmodeCSmodeEnginerunthresholdEngineTypeMax.power[kW]Max.torque[Nm]MotorTypeMax.power[kW]Max.torque[Nm]Max.speed[rpm]Max.voltage[V]L4DOHCAtkinson105165Interiorpermanentmagnetsynchronousmotor12430712584700coupledCVTunit.ThisAtkinsoncycleengineemploysVTEC,electricVTCandcooledEGR,andfrictionhasbeenreduced,enablingachievementofbothhighoutputof105kWand10%higherefficiencyintermsofBrakeSpecificFuelConsumption(BSFC)comparedtotheprevious2.0Lengine.Themotorachieveshighoutputof124kWandhighefficiencyof96%(max.)byincreasingthevoltagewithaboosterandmakinguseofreluctancetorque.Table1liststhemajorspecificationsofthepowertrain.3.3.OverviewofPlug-inHybridOperationFigure3showsanoverviewofplug-inhybridoperation.Plug-inhybridoperationisclassifiedintothefollowingtwomodes.ThefirstmodeiscalledChargeDepletingmode(CDmode).ThismodemainlyperformsEVdriveusingtheelectricenergystoredintheLi-ionbatterybyplug-incharging.CDmodeexpandstheEVdriveoperationrangeandsecuresa13-mileEVrangebysettingahighthresholdforenginestartasshowninFig.3.3.OverviewofSystem3.1.OverallConfigurationFigure1showsthemajorcomponentsoftheSPORTHYBRIDi-MMDsystem.AnelectriccoupledCVTcomprisingtwomotors(motorandgenerator)andaclutchisbuiltintothetransmissioncaseandlocatedinsidetheengineroomtogetherwithanewlydevelopedAtkinsoncycleengineoptimizedforHEV(2).APowerControlUnit(PCU)incorporatingavoltagecontrolunitthatbooststheLi-ionbatteryvoltage,amotorcontrolunitusedtocontrolthemotor(3)andgenerator,andaninverterislocatedabovetheelectriccoupledCVT.AnIntelligentPowerUnit(IPU)consistingofaLi-ionbattery,aDC/DCconverter,andabatterycontrolunitthatcontrolstheLi-ionbattery