车辆工程专业毕业论文外文翻译1doc.docx

车辆工程专业毕业论文外文翻译1doc.docx

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车辆工程专业毕业论文外文翻译1doc

Driveforcecontrolofaparallel-serieshybridsystem

Abstract

Sinceeachcomponentofahybridsystemhasitsownlimitofperformance,thevehiclepowerdependsontheweakestcomponent.Soitisnecessarytodesignthebalanceofthecomponents.Thevehiclemustbecontrolledtooperatewithintheperformancerangeofallthecomponents.Wedesignedthespecificationsofeachcomponentbackwardfromtherequireddriveforce.Inthispaperwedescribeacontrolmethodforthemotortorquetoavoiddamagetothebattery,whenthebatteryisatalowstateofcharge.SocietyofAutomotiveEngineersofJapan,Inc.andElsevierScienceB.V.Allrightsreserved.

1.Introduction

Inrecentyears,vehicleswithinternalcombustionengineshaveincreasinglyplayedanimportantroleasameansoftransportation,andarecontributingmuchtothedevelopmentofsociety.However,vehicleemissionscontributetoairpollutionandpossiblyevenglobalwarming,whichrequireeffectivecountermeasures.Variousdevelopmentsarebeingmadetoreducetheseemissions,butnofurtherlargeimprovementscanbeexpectedfrommerelyimprovingthecurrentenginesandtransmissions.Thus,greatexpectationsarebeingplacedonthedevelopmentofelectric,hybridandnaturalgas-drivenvehicles.Judgingfromcurrentlyapplicabletechnologies,andthecurrentlyinstalledinfrastructureofgasolinestations,inspectionandservicefacilities,thehybridvehicle,drivenbythecombinationofgasolineengineandelectricmotor,isconsideredtobeoneofthemostrealisticsolutions.

Generallyspeaking,hybridsystemsareclassifiedasseriesorparallelsystems.AtToyota,wehavedevelopedtheToyotaHybridSystem（hereinafterreferredtoastheTHS）bycombiningtheadvantagesofbothsystems.InthissensetheTHScouldbeclassifiedasaparallel-seriestypeofsystem.SincetheTHSconstantlyoptimizesengineoperation,emissionsarecleanerandbetterfueleconomycanbeachieved.Duringbraking,Kineticenergyisrecoveredbythemotor,therebyreducingfuelconsumptionandsubsequentCO2emissions.

EmissionsandfueleconomyaregreatlyimprovedbyusingtheTHSforthepowertrainsystem.However,theTHSincorporatesengine,motor,batteryandothercomponents,eachofwhichhasitsownparticularcapability.Inotherwords,thedrivingforcemustbegeneratedwithinthelimitsofeachrespectivecomponent.Inparticular,sincethebatteryoutputvariesgreatlydependingonitslevelofcharge,thedrivingforcehastobecontrolledwiththisinmind.

ThisreportclarifiestheperformancerequiredoftherespectiveTHScomponentsbasedonthedrivingforcenecessaryforavehicle.Themethodofcontrollingthedrivingforce,bothwhenthebatteryhashighandlowcharge,isalsodescribed.

2.Toyotahybridsystem（THS）[1,2]

AsFig.1shows,theTHSismadeupofahybridtransmission,engineandbattery.

2.1.Hybridtransmission

Thetransmissionconsistsofmotor,generator,powersplitdeviceandreductiongear.Thepowersplitdeviceisaplanetarygear.Sungear,ringgearandplanetarycarrieraredirectlyconnectedtogenerator,motorandengine,respectively.Theringgearisalsoconnectedtothereductiongear.Thus,enginepowerissplitintothegeneratorandthedrivingwheels.Withthistypeofmechanism,the

revolutionsofeachoftherespectiveaxesarerelatedasfollows.Here,thegearratiobetweenthesungearandthe

—MEJthanicalPower

ElectricalPowsr

Fig.1.SchematicofToyotahybridsystem（THS）.

ringgearis

p:

2-上'

whereNeistheenginespeed,NgthegeneratorspeedandNmthemotorspeed.

Torquetransferredtothemotorandthegeneratoraxesfromtheengineisobtainedasfollows:

：

2i

motoraxistorque：

二Te.

r1+p

whereTeistheenginetorque.

Thedriveshaftisconnectedtotheringgearviaareductiongear.Consequently,motorspeedandvehiclespeedareproportional.Ifthereductiongearratioisn,theaxletorqueisobtainedasfollows:

aidetorque:

（■-_-—Te+Tmjff.（4（

whereTmisthemotortorque.

Asshownabove,theaxletorqueisproportionaltothetotaltorqueoftheengineandthemotoronthemotoraxis.Accordingly,wewillrefertomotoraxistorqueinsteadofaxletorque.

2.2.Engine

Agasolineenginehavingadisplacementof1.5lspeciallydesignedfortheTHSisadopted[3].Thisenginehashighexpansionratiocycle,variablevalvetimingsystemandothermechanismsinordertoimproveengineefficiencyandrealizecleaneremissions.Inparticular,alargereductioninfrictionisachievedbysettingthemaximumspeedat4000rpm（=Nemax）.

2.3.Battery

Assealednickelmetalhydridebatteryisadopted.Theadvantagesofthistypeofbatteryarehigh

powerdensityandlonglife.thisbatteryachievesmorethanthreetimesthepowerdensityofthosedevelopedforconventionalelectricvehicles[4].

3.Requireddrivingforceandperformance

TheTHSoffersexcellentfueleconomyandemissionsreduction.Butitmusthavetheabilityto

outputenoughdrivingforceforavehicle.Thissectiondiscussestherunningperformaneerequiredofthevehicleandtheessentialitemsrequiredoftherespectivecomponents.

Roadconditionssuchasslopes,speedlimitsandtherequiredspeedtopassothervehiclesdeterminethepowerperformancerequiredbythevehicle.Table1indicatesthepowerperformanceneededinJapan.

3.1.Planetarygearratiop

Theplanetarygearratio（p）hasalmostnoeffectonfueleconomyand/oremissions.Thisisbecausetherequiredenginepower（i.e.enginecondition）dependsonvehiclespeed,drivingforceandbatterycondition,andnotontheplanetarygearratio.Conversely,itislargelylimitedbythedegreeofinstallabilityinthevehicleandmanufacturingaspects,leavinglittleroomfordesign.InthecurrentlydevelopedTHS,p=0.385.

3.2.Maximumenginepower

Sincethebatterycannotbeusedforcruisingduetoitslimitedpowerstoragecapacity,mostdrivingisreliantonenginepoweronly.Fig.2showsthepowerrequiredbyavehicleequippedwiththeTHS,basedonitsdrivingresistance.Accordingly,thepowerthatisrequiredforcruisingonalevelroadat140km/horclimbinga5%slopeat105km/hwillbe32kW.Ifthetransmissionlossistakenintoaccount,theenginerequires40kW（=Pemax）ofpower.TheTHSusesanenginewithmaximumpowerof43kWinordertogetgoodvehicleperformancewhilemaintaininggoodfueleconomy.

TjhJe1

uiredlieitkmsEbrYfhi讨己

Ikm

RcquiriMiabdiiy

CniLsin^iiminiLjinAbiJal^lewuphillrc^adAbUilyfaruphill

road3lhigJispeed

30%{11）

5%（3>it105kmh

5%（3）it130krn-linnttintancnuft

33Maximumgeneratortorque

AsdescribedinSection2,themaximumenginespeedis4000rpm（=Nemax）.Toattainmaximum

torqueatthisspeed,maximumenginetorqueisobtainedasfollows:

Temat=95.5（Nm）.

1000xmax

l2TT'60fxArma\

FromEq.（3）,themaximumtorqueonthegeneratoraxiswillbeasfollows:

Temsx=26-5（Nm）.

i+p

Thisisthetorqueatwhichthegeneratorcanoperatewithoutbeingdriventooverspeed.Actually,highertorqueisrequiredbecauseofacceleration/decelerationofgeneratorspeedanddispersionofengineand/orgeneratortorque.Byadding40%torquemargintothegenerator,thenecessarytorqueiscalculatedasfollows:

Tema\x.L4=7jtijk-37,1（Nm|.+p

3.4.Maximummotortorque

FromFig.3,itcanbeseenthatthemotoraxisneedstohaveatorqueof304Nmtoacquirethe30%slopeclimbingperformanee.Thistorquemerelybalancesthevehicleontheslope.Toobtainenough

startingandacceleratingperformanee,itisnecessarytohaveadditionaltorqueofabout70Nm,orabout370Nmintotal.

FromEq.

（2）,thetransmittedtorquefromtheengineisobtainedasfollows:

y!

—Temax=70.0（Nm）.

Consequently,amotortorqueof300Nm（=Tmmax）isnecessary.

3.5.Maximumbatterypower

AsFig.2shows,drivingpowerof49kWisneededforclimbingona5%slopeat130km/h.Thus,thenecessarybatterypowerisobtainedbysubtractingtheengine-generatedpowerfromthis.Asalreadydiscussed,ifanenginehavingtheminimumrequiredpowerisinstalled,itcanonlyprovide32kWofpower,sotherequiredbatterypowerwillbe17kW.Ifthepossiblelossthatoccurswhenthebatterysuppliespowertothemotoristakenintoaccount,batterypowerof20kWwillbeneeded.Thus,itisnecessarytodeterminethebatterycapacitybytargetingthisoutputonanactualslope.Table2liststherequiredbatteryspecifications.

Table3summarizesthespecificationsactuallyadoptedbytheTHSandtherequirementsdeterminedbytheabovediscussion.Therequireditemsrepresentanexamplewhenminimumenginepowerisselected.Inotherwords,iftheengineischanged,eachoftheitemshavetobechangedaccordingly.

Tub-le2

Requiredbatter）Kpecificatians

Item.

Value

2SSV

Power

20IcW

Energy

1.8kWh

Table3

Requiredand.actualE-pcciOralions

oftheTI1WcompDaienEs

Spcciiication

Requiredvdlue

THS

tinlineeh髯imumpox弋丁

44）k.W

Cicncnit口:

rm^ximuinnilorquc

17.1Nm

SsN]n

hi口tormaiimiumtorque

Nm

305Mm

liallerymdiiinnium

21LW

uodlerwrgy

（inKtantantnusI

LHkWh

4.Drivingforcecontrol

5.

TheTHSrequirescontrolsnotnecessaryforconventionalorelectricvehiclesinordertocontroltheengine,motorandgeneratorcooperatively.Fig.4outlinesthecontrolsystem.

Fig.4.ControldiagramoftheTHS.

Inputsofcontrolsystemareacceleratorposition,vehiclespeed（motorspeed）,generatorspeedandavailablebatterypower.Outputsaretheengine-requiredpower,generatortorqueandmotortorque.

First,drivetorquedemandedbythedriver