20Design and implementation of a novel hybrid-elec

Designandimplementationofanovelhybrid-electric-motorcycletransmissionKuen-BaoSheu*,Tsung-HuaHsuInstituteofMechanicalandElectro-MechanicalEngineering,NationalFormosaUniversity,64WunhuaRoad,Huwei,Yuenlin63208,Taiwan,ROCReceived30July2005;receivedinrevisedform2October2005;accepted8October2005Availableonline19December2005AbstractThishybridpowersystemincorporatesamechanicaltyperubberV-belt,continuously-variabletransmission(CVT)andchaindrivestocombinepowerofthetwopowersources,agasolineengineandanelectricmotor.Thesystemusesfourdifferentmodesinordertomaximizetheperformanceandreduceemissions:electric-motormode;enginemode;engine/chargingmode;andpowermode.Themainadvantagesofthisnewtransmissionincludetheuseofonlyoneelectricmotor/generatorandtheshiftoftheoperatingmodeaccomplishedbythemechanical-typeclutchesforeasycontrolandlowcost.Kinematicanalysesanddesignareachievedtoobtainthesizeofeachcomponentofthissystem.Adesignexampleisfabricatedandtested.2005ElsevierLtd.Allrightsreserved.Keywords:Hybridelectricmotorcycle;Transmission;CVT1.IntroductionMotorcycles/scootersareapopularmodeoftransportationinmanyurbanareasofAsia,suchasTaiwanbecauseoflimitedspace,shortdailytripdistance,populationdensityandtheeasyoperationandmaintenanceofmotorcycles.However,theexhaustsfromgas-olinemotorcyclescauseseriousenvironmentalpollutioninTaiwanscities.TheEnviron-mentalProtectionAdministrationoftheROChasimplementedsomepoliciestoreduce0306-2619/$-seefrontmatter2005ElsevierLtd.Allrightsreserved.doi:10.1016/j.apenergy.2005.10.004*Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](K.-B.Sheu).AppliedEnergy83(2006)959–974[1].Tofacil-itatethis,thegovernmentandindustryhavebeenapplyingfuel-celltechnologytopowerscooters[2–5].However,thegoalofreplacingpollutingcombustion-enginemotorcycleswithbatterypoweredoneshasnotbeensuccessfulinTaiwan[6].Existingandproposedbattery/fuelcellpoweredmotorcycledesignshavelowperformanceandarenotlikelytodisplacethegasolinemotorcycleinthenearfuture[7,8].Anotherapproachtoreducebothpollutionandgetbetterperformanceistoutilizeahybridconceptofinternal-com-bustionengineandbatteryatthisstage.Overthepastfewyears,hybridelectricvehicles(HEVs),primarilyautomobiles,havebeenactivelydevelopedandmarketed[9–14].Thisstudyconsidersthedesignofahybridpower-transmittingsystemthatissuitableformotorcycles.In1997,HondaMotorsreleasedahybridtwo-wheelerconceptintheTokyomotorshowwiththekeygoalsofa60%reductioninCO2emissionand2.5timesbetterfuel-efficiency.Inthissystem,awater-cooled49ccgasolineengineispackedwithaDCbrushlesselectric-motortogetherdrivingtherearwheel.Thegasolineenginedeliverspowerforhigh-speedperformanceandforhillclimbingwhiletheelectricmotorengagesforlow-speedcruising.In1999,AVLCompanyproposedahybridsystemthatuseda50cccarburettedlean-burntwo-strokeenginewitha0.75kWelectricmotormountedontheenginecrankshaftmainlytoprovideincreasedtorqueduringacceleration[15].MatsutoandWachigaialsoproposedamotorcyclehybrid-drivesystem[16–18].Themaincomponentsofthissystemconsistsofthetwopowersourcesofanengineandanelectricmotor,atractiondrivecontinuously-variabletransmission(CVT),afinalreductiondriveandthreeclutches.Thetransmissionshaftandtheelectricmotorshaftarecoaxialinseriesinthelongitudinaldirectionofthevehicularbodyandinparallelwiththecrankshaftoftheengine.Traditionally,thetransmissiondevicesusedformotorcyclesaredividedintotwocate-gories:(1)steppedtransmissiondevices,thatworkbyalternatingthegeardrives,and(2)CVTs,thattransmitpowerbyusingarubberV-shapedbelt.AdvantagesoftherubberV-beltCVTsincludesmoother-speedcharacteristics,adequatespeedratio,asimplermech-anism,lowcost,lessmaintenance,etc.However,themechanicalefficiencyofthemechan-ical-typerubberV-beltCVTisquitelow,especially,attheinstantofspeedratiochangewithfrequentstops[19,20].Thispaperpresentsanovelhybridelectricmotorcycletransmissionwhoseprimaryfea-tureisamechanicaltyperubberV-beltCVTandchaindrivestocombinethepoweroftwopowersources,agasolineengineandanelectricmotor.Thehybridpowersystemistoruntheelectricmotoratstart-upandduringlowspeeds,sothattheemissionsinurbanareasarelimited.Asthevehiclespeedincreasestoandpassesamediumspeed,theenginepoweristransmittedtotherubberV-beltCVTdrivingthevehicle.Thiscombinationcanavoidthelow-efficiencyregionsoftheCVTandretaingoodhandling.Thispaperbeginswithadescriptionofthehybrid-electrictransmissionandproceedswithakinematicanalysisanddesigntoobtainthesizeofeachcomponentofthissystem.Finally,theprototypeofthisnewdesignisfabricatedandtested.2.ParallelhybridtransmissionTraditionally,HEVsfortheautomotiveindustrieswereclassifiedintotwotypes,serieshybridandparallelhybrid.WiththerecentdevelopmentsofHEVs,theycannowbecat-960K.-B.Sheu,T.-H.Hsu/AppliedEnergy83(2006)959–974egorizedinfourkinds:serieshybrid,parallelhybrid,series–parallelhybrid,andcomplexhybrid[21].AseriesH