Use-of-electromagnetic-clutch-water-pumps-in-vehic

UseofelectromagneticclutchwaterpumpsinvehicleenginecoolingsystemstoreducefuelconsumptionYoonHyukShina,SungChulKima,*,MinSooKimbaGreenCarPowertrainR&DDivision,KoreaAutomotiveTechnologyInstitute,Chungnam330-912,RepublicofKoreabSchoolofMechanicalandAerospaceEngineering,SeoulNationalUniversity,Seoul151-744,RepublicofKoreaarticleinfoArticlehistory:Received28November2012Receivedinrevisedform29April2013Accepted30April2013Availableonline21June2013Keywords:ElectromagneticclutchwaterpumpPlanetarygearFuelconsumptionWarm-upNEDC(NewEuropeanDrivingCycle)abstractIngeneral,whentheinternalcombustionengineofavehicleisstarted,itsoperationallyconnectedcoolingsystemprovidesexcessivecooling,resultinginunnecessaryenergyconsumptionandexcessiveemissionofexhaustgas.Iftherotationalspeedoftheengineishigh,theexcessivecoolingcausesthecombustionefficiencytodecrease.Therefore,bettercontroloftheoperatingtemperaturerangeoftheenginethroughuseofanactivecoolingsystemcanachievebetterfueleconomyandreductionofexhaustgasemission.Effectivecontrolofthecoolingsysteminaccordancewiththeoperatingconditionsoftheenginecanberealizedbychangingthemassflowrateofthecoolant.Inthisstudy,wedesignedelec-tromagneticclutchwaterpumpsthatcancontrolthecoolantflow.Wemadetwotypesofwaterpump:(1)aplanetarygear(PG)-typewaterpumpwhichcanreducetherotationspeedofthewaterpumpby65%,comparedwithapulley;and(2)anon/off-typewaterpumpwhichcancompletelystoptherotationoftheimpeller.Theperformanceevaluationofthesepumpsconsistedofawarm-uptestandtheNewEuropeanDrivingCycle(NEDC).Warm-uptestresultsshowedthatthetimerequiredtoachieveatemperatureofapproximately80
CwiththePGwaterpumpandtheon/offwaterpumpwasimprovedby7.3%and24.7%respectively,comparedwiththatofaconventionalwaterpump.BasedontheNEDCresults,wedeterminedthatthefueleconomyoftheengineusingthePGwaterpumpandtheon/offwaterpumpwasimprovedby1.7%and4.0%comparedwiththefueleconomywhenusingthecon-ventionalwaterpump.Theapplicationofclutchwaterpumpsisexpectedtocontributetotheimprovementofenginecoolingsystemperformance,becausetheireffectinreducingthefuelcon-sumptionrateissimilartothatofanelectricwaterpump.
2013ElsevierLtd.Allrightsreserved.1.IntroductionAsfossilfuelproblemsandenvironmentalissueshavebecomeincreasinglycritical,thedevelopmentofecotechnologiestoimprovetheenergyefficiencyofvehiclesisincreasinglyimportant.Furthermore,regulationsforautomobilefuelconsumptionandemissioncontrolhavebeenbecomestringentinternationally.InEurope,Euro6willtakeeffect,andintheUSA,theissueofCO2emissioncontrolisanimportantconsiderationinenactmentofnewstatutes.Recently,hybridelectricvehicleshavebeenactivelystudiedasagoodmeansofreducingenergyusageandharmfulemissions[1,2].However,asidefromstudiesonimprovingtheenergyefficiencyofelectricandhybridelectricvehicles,thereisrenewedinterestinefficiencyenhancementtechnologiesforthetraditionalinternalcombustionengine.Thesetechnologieshavebeenregardedasvaluableagaininrecentyears,becauseadvancedtechnologieshavebeendevelopedthatcanbeappliedtotraditionalvehiclesatlowcostandwithcomparativeease.Otherstudiesareneededtoimprovetheefficiencyoftheheavy-dutydieselengine.High-efficiencytechnologytosavefuelinconventionalvehicleshasbeensuggestedforvariouspartsofthevehiclesystem.Repre-sentativemethodsofvehicleimprovementincludereductionsinweightandairresistance,andimprovementsinthermalefficiency.Inparticular,optimizationofthetypicalcoolingsystemforinternalcombustionenginesisafieldofinterestfordevelopinghighenergyefficiencyinvehicles[3e5].Becausevehiclesafetyismoreimpor-tantthanenergyefficiency,theenhancedmanagementofenginethermalcharacteristicshasresultedinrealizingadvancedfunctionsinvehiclessuchascompactfront-endmoduleandactivethermalmanagementsystem[6,7].Thetypicalenginecoolingsystemconsistsofawaterpump,thermostat,radiator,andengineblockwaterjacket.Conventional*Correspondingauthor.Tel.:þ82415593093;fax:þ82415593070.E-mailaddress:[e-mail](S.C.Kim).ContentslistsavailableatSciVerseScienceDirectEnergyjournalhomepage:
2013ElsevierLtd.Allrightsreserved.(2013)624e631mechanicalwaterpumpsareoperatedinproportiontotheenginespeedtocirculatethecoolantinthecoolingsystem.Inthisconfig-uration,thedirectconnectionbetweentheenginecrankshaftandthewaterpumpresultsinanexcessivemassflowrateofcoolantsatenginecoldstartandunderpartialloadconditions.Toavoidtheexcessivecoolingeffectandmeettheneedforhighefficiencyinthecoolingsystem,electrificationofthecoolingcomponentshasbeenproposedasagoodalternative.Asaresult,theelectricwaterpumpsandintelligentthermostatvalveshavebeenusedinvehiclecoolingsystems[8e10].Theelectriccomponentscanprovideefficientcoolingondemandunderalloperatingconditionsbychangingthecoolantmassflowrate.Theelectricwaterpump’sefficiencyishigherthanthatoftheconventionalmechanicalwaterpump.However,theelectricalenergyforandelectricpump(andotherelectricfeaturesofthevehicle)comesfromthetransformationofmechanicaltoelectricalenergybythealternator,whichoccurswithanenerg