盘式制动器中英文对照外文翻译文献

PAGEPAGE20中英文对照外文翻译文献(文档含英文原文和中文翻译)外文：AnExperimentalAnalysisofBrakeEfficiencyUsingfourFluidsinaDiscBrakeSystemABSTRACTThepaperstudiesdiscbrakefailureinMini-busesusinganexperimentalanalysistotestthemaximumbrakingforcewhendifferentbrakefluidssuchasclean,lessdirty,dirtyandsoapywatersolutionwereusedinthebrakingsystem.Theexperimentalresultsclearlyshowedthatthesoapsolutionappearstobethebestfluidasfaraslowviscosityandstabilityofviscositywithincreaseintemperatureareconcerned.However,thesoapsolutionisnotcompatiblewithotherfluidwhichmakesitdifficulttobesubstituteasacleanbrakefluid.TheresultoftheThepraUniversalBrakeTestingEquipmentusedforthebrakingefficiencytestindicatedthatapedalbrakeof117kNproduceabrakeforceof0.96kNforcleanbrakefluid,0.91kNforthelessdirty,0.85kNfordirtyand1.44kNforsoapsolution.Thevalueof1.44kNwhichwasachievedwhenthesoapsolutionwasusedindicatedapositivebrakingforceandtheindicatingthatsoapsolutioncouldbeusedtoproduceahighpedalforcewithinaveryshorttime(about10-30min)andcanthereforebeusedonlyincaseofemergency.Thebrakeefficiencytestindicatedthatunderhotconditionsthebrakingefficiencyisreducedandthepresenceofairinthesystemrendersthebrakingineffectivebecausehigherpedalforcewasneededtobeabletoproduceasignificantbrakingforcewhichisnotedforcausingbrakefailure.Keywords:Brakefade,brakefailure,discbrake,efficiency,pedalforceINTRODUCTIONWhenavehicleisaccelerated,energysuppliedbytheenginecausesthevehicle’sspeedtoincrease.Partofthisenergyisinstantlyusedupinovercomingfrictionalandtractiveresistancebutalargeamountofitremainsstoredinthevehicle.AccordingtoHeinz(1999)thisenergyofmotioniscalledthekineticenergyandtheexistenceofkineticenergyisobservedwhenavehicleismovingandneutralgearisselected.Thevehicledoesnotimmediatelycometorest;insteadittravelsforaconsiderabledistancebeforeitbecomesstationary.Inthiscasethestoredenergyisusedtodrivethevehicleagainsttheresistancesthatopposethevehicle’smotion.Relyingontheseresistancestoslowdownavehiclecouldcausemanyproblems,soanadditionalresistancecalledabrakeisneededtoconvertthekineticenergytoheatenergyatafasterrateinordertoreducethespeedofthevehicleMcpheeandJohnson(2007).Thisreducesthespeedofthevehicleatafasterrateandbringsthevehicletorestwithintheshortestpossibletimewhenthebrakesareapplied.FromthepointofviewofJohnsonetal.(2003)mostautomotivesystemsinusetodayutilizefrontdiscbrakes,butfour-wheeldiscsystemsarealsocommonIndiscbrakes,therotorrotateswiththewheelandthepadsmoveouttorubtherotorwhenthebrakesareapplied.Mostdiscbrakesusefloatingcalipers.Thecaliperslidesinandoutasthebrakesareappliedandreleased.Thepistonmovestheinsidepadoutandpushestheoutsidepadintotherotorbyslidingthecaliperbacktowardtherotor.TheuseofdiscbrakestoreducespeedorbringthevehicletorestwheninmotioncannotbeoveremphasizedifthesafetyoftheoccupantistobeguaranteedHeinz(1999).Tobringavehicletoastop,thediscbrakeshavetoabsorballtheenergygiventothevehiclebytheengineandthatduetothemomentumofthevehicle.Thisenergymustthenbedissipated.Inmostvehiclediscbrakes,theenergyisabsorbedbyfriction,convertedintoheatandtheheatdissipatedtothesurroundingair(Thoms,1988).Astheenergyisabsorbed,thevehicleissloweddown;inotherwords,itsmotionisretarded.Thebrakesmustalsopullupthevehiclesmoothlyandinastraightlinetobringthevehicletoastopposition.Itisthereforeveryimportantthatthediscbrakesofvehiclesoperatewiththehighestefficiency.Thiscouldreducetherateofaccidentsduetobrakefailuresothatlifeandpropertycouldbepreservedandalsotoensurethatoccupantsofthesecommercialvehiclesgoabouttheirnormalliveswithoutanyfearofbeinginvolvedinanaccident.AvailablecrashdatainGhanasuggeststhatabout1,900personsarekilledannuallyinroadtrafficcrashes(Afukaaretal.,2008)andthatmorethan40%oftheroadtrafficfatalitiesareoccupantsofcars,busesandtrucks.Mostoftenthannot,someoftheroadaccidentsinvolvingcommercialvehicles,suchasthemini-buseshavebeenattributedtothefailureofthediscbrakes.Thereasonfortestingtheviscosityofthesebrakefluids,especiallythatofthesoapsolutionwasasaresultofthepracticeofmostGhanaiandriverssometimesusingthesoapysolutionasasubstitutetotheoriginalbrakefluidinthebrakingsystemandalsousingdirtybrakefluidwhichhasbeenusedforbleedingpurposes.Themainobjectiveofthisstudywhichispartofalargerworkseekstoinvestigateandestablishthereasonsforthediscbrakefailureduetobrakefluidalsochecktheefficiencyofthefourdifferenttypesoffluidsusedinthetransmissionofbrakingforces.Thestudylookedatthemaximumbrakingforcewhenusingclean,lessdirty,dirtyandsoapywatersolutioninthebrakingsystem.ItalsolookedatthebrakingforcewhenthebrakingsystemiswithorwithoutservounitandoperatingundercoldorhotconditionwithairorwithoutairinthebrakingsystemDISCBRAKESThediscbrakeconsistsofanexposeddiscwhichisattachedtothehubflange;thetwofrictionpadsarepressedontothisdisctogiveabrakingaction.Figure1a,showsthediskbrakesystemofacarandpadthatisseparatedfromwheelassemblytobettershowsthediskandthepadinslidingcontact.Asitcanbeseen,typicaldiskbrakesystemandcaliperassemblyofasoliddiskbrakerotoriscompletelynoticeable.Figure1bshowsschematicformofthediskandthepadinslidingcontactassembly.(a)(b)Fig.1:DiscbrakeThepadsaremovedbyhydraulicpistonsworkingincylindersformedinacaliperthatissecuredtoafixedpartoftheaxle.Whenthehydraulicpressureisappliedtothetwocylindersheldinthefixedcaliper,thepistonsmove;thisactionforcesthefrictionpadsintocontactwiththerotatingcastirondisc.Thesandwichingactionofthepadsonthediscgivesaretardingactionandheatgeneratedfromtheenergyofmotionisconductedtothedisc.Greaterpartofthediscisexposedtotheair;thereforeheatiseasilyradiated,withtheresultthatthebrakecanbeusedcontinuouslyforlongperiodsbeforeseriousfadeoccurs.Sincethefrictionpadsmoveatarightangletothedisc,anydropinthefrictionvaluedoesnotaffecttheforceappliedtothepad.Asaresultthistypeofbrakeisnotlesssensitivetoheat(Mudd,1972).Thediscbrakewasdevelopedtominimizethefadeproblems.Whenfadingoccurs,thedriverhastoapplyamuchlargereffortandinextremecasesitbecomesimpossibletobringthevehicletorest.Noassistanceisobtainedfromtherotatingdisctoaidthedriverintheapplicationofadiscbraketoachieveagivenretardation.Adiscbrakerequiresagreaterpedalpressureandtoachievethispressurerequiredthehydraulicbrakingsystemusingagoodqualitybrakefluidinitsoperation.Thefluidusedinthehydraulicbrakingsystemsisavegetableoilwithcertainadditives.AccordingtoNunneyetal.(1998)agoodbrakefluidshouldhavethefollowingrequirements,lowviscosity,highboilingpoint,compatibilitywithrubbercomponents,lubricatingproperties,resistancetochemicalageingandcompatibilitywithotherfluids.However,mostGhanaiandriverssometimesusedotherfluidsuchasdirtybrakefluid,lessdirtyfluidandevensoapywatersometimesasasubstitutedtotheoriginalbrakefluid.Thisstudyamongotherthingswillalsoinvestigatewhichofthesebrakefluid,clean,dirty,lessdirtyandsoapywaterwillhavethebestviscosity,highboilingpointandlessbrakingforce.MATERIALSANDMETHODSThedesignusedforthisstudywasexperimentwhichemployedtheusedofviscometerandThepraUniversalAutomotiveBrakeTestingmachinetochecktheefficiencyofthefourfluidsinthetransmissionofbrakingforces.Laboratoryanalysis:TheviscositytestsonthefourdifferentliquidswerecarriedoutattheKwameNkrumahUniversityofScienceandTechnology(KNUST)Thermodynamicslaboratory.Theliquidswerecleanbrakefluid,lessdirtybrakefluid,dirtybrakefluidandsoapsolution.Itwasnecessarytofindouthowtheviscosityofdifferentqualitiesofbrakefluidaffectedbrakingefficiencyandtofindoutwhethertherewasanycorrelationbetweentheseandtheoccurrenceofbrakefailure.Viscositytestonthevariousfluidsused:TheviscositytestwascarriedoutonaRedwoodViscometerinFig.2onthefourdifferentkindsoffluidstodeterminetheirviscosities.Theapparatusconsistsofaverticalcylindercontainingthefluidundertestwhichwasallowedtoflowthroughacalibratedorificesituatedatthecentreofthecylinderbase.Theorificeisclosedbyaballvalvewhenitisnotbeingused.Fig.2:RedwoodviscometerusedtodeterminetheviscosityofthefluidsTheoilcylinderissurroundedbyawaterjacketwhichmaintainsthelubricantundertestatarequiredtemperaturebymeansofaBunsenburnerflameappliedtotheheatingtube.Thethermometerforthewaterinthejacketismountedinapaddle-typestirrerwhichcanberotatedbyhand,usingthehandle(Zammit,1987).Procedurefortestingvariousviscositiesofthefluids:Totesttheviscosityofafluid,thewaterjacketwasfilledwithwaterwiththeorificeballvalveinposition.Fluidwaspouredintothecylindertothelevelofthepointer.A50mLmeasuringflaskwasplacedcentrallyundertheorifice.Thewaterwasstirredgentlyuntilthewaterandfluidthermometerswerethesame(roomtemperature,30ºC).Thetemperaturewasrecorded.Theballvalvewasthenraisedandastopwatchusedtorecordthetime(inseconds)fora50mLoffluidtoflowintothemeasuringflask.Thetestwasrepeatedwiththefluidtemperaturesincreasingby10ºCeachtimeupto90ºC.AllthedataforthefourdifferentfluidswererecordedasshowninTable1Theprauniversalstandautomotivebraketestingequipment:TheThepraUniversalStandAutomotivebraketestingequipmentisstructuredinsuchawaythatthedrivenpart,suchasbrakedisc,waspluggedontothemotorshaft.Thebrakeanchorplateandthecaliperarefastenedtoaflangeviaalinkageofbarwhichisconnectedtotheflange.Thebrakeforceismeasuredanddisplayedonadigitalindicator.Theindividualunitsarepluggedintothetwospan-frameswhicharefastenedtobothsides.Allthebrakecomponentsusedinthetestingequipmentareoriginalvehiclecomponents.Thepedalforceismeasuredattheactuatinglinkageofthebrakemastercylinderanddisplayedonadigitalindicator(Technolab,2009)RESULTSANDDISCUSSIONExperimentalresultsofviscositytest:Table1presenttheresultsofviscositytestinanexperimentforthefourfluids,usingtheRedwoodViscometer.FromthetestresultsobtainedusingRedwoodviscometer,Viscosity-Temperaturegraphsforthefluidswereplotted.Figure3showstheplotofviscosityagainsttemperatureofthefourfluids.Table1:ViscositytestValuesofthevariousviscositieswerecalculatedusingtheformula:V=hfρgD232hfvValuesofthevariousviscositieswerecalculatedusingtheformula:V=hfρgD232hfvwhere,V:TheViscosityhf:Thecapillaryheightρ:Thedensityofthefluidg:AccelerationduetogravityD:Thediameteroftheorificev:Thevelocity(Birdetal.,1960)FromFig.3thedirtyfluidhasthehighestviscosityfollowedbythelessdirtyfluid,cleanfluidandsoapsolutioninthatorder.FromtheresultsshowninFig.2andtheviscositytestshowninTable1,thesoapsolutionappeartobethebestfluidasfaraslowviscosityandstabilityofviscositywithincreaseintemperatureareconcerned.However,itislesscompatiblewithotherfluids,difficulttomixeasilywithotherbrakefluidsandhasalowboilingpointwhichwillnotmakeitsuitabletobesubstituteascleanbrakefluid(Nunneyetal.,1998).Thecleanbrakefluidisnextasfarasviscosityandstabilityofviscositywithincreaseintemperatureareconcerned.Ontheotherhand,itsatisfiesalltheotherrequirementsofagoodfluidforthebrakingsystemgiveninTable1.AccordingtoMudd(1972)andNunneyetal.(1998),agoodbrakefluidshouldhavepropertiessuchashighboilingpoint,compatibilitywithrubbercomponents,goodlubricationproperties,resistancetochemicalageing(longshelflife)andcompatibilitywithotherfluids.Thelessdirtyfluidisveryunstableasfarasviscositychangewithtemperatureincreaseisconcerned.Itisthereforenotveryreliableinabrakingsystemsinceitsbehaviorchangesasthebrakingsystemheatsup.Theviscosityofthedirtyfluidisstablewithincreaseintemperature,however,itisveryviscous(235-178kgs/m3inthetemperaturerange30to90ºC).Itwillthereforenotbegoodandeffectiveinbrakeforcetransmission.Fromtheseresultsandliterature,itisobviousthatthecleanbrakefluidismoresuitableforthetransmissionofbrakingforceasit’spossessallthegoodbrakefluidqualities.Experimentalresultsofthediscbrakesystem:ThesesectionspresenttheresultsanddiscussionoftheexperimentsusingthefourfluidsinaDiscbrakesystemunderdifferentconditions.TestresultsforhotandcoldconditionsoftheDiscbrakesystemusingaservosystemandwithoutusingaservosystemwereconsidered.Discbrakeincoldconditionwithandwithoutservounit:TheresultinTable2clearlyshowsthepedalforceandthebrakeforceforclean,lessdirty,dirtyandsoapsolutionwhenusingdiscbrakeincoldconditionwithservounitwiththeThepraUniversalBrakeTestingEquipment.Apedalbrakeof117kNproduceabrakeforceof0.96kNforacleanbrakefluid,Table2:ResultsofdiscbrakeincoldconditionwithservoTable3:Resultsofdiscbrakeinhotconditionwithservo0.91kNforthelessdirty,0.85kNfordirtyand1.44kNforsoapsolution.Comparatively,amaximumbrakeforceisachievedwhenthefluidisclean.Whenthereisthepresenceofdirt,thebrakeforcedecreasesandthereforemorepedalforceisneededtotakeupthewithoutservolosscreatedbythedirt.Hencethegreaterthedirt,thegreaterthepedalforcerequired.Thevalueof1.44kNwhichwasachievedwhenthesoapsolutionwasusedindicatedapositivebrakingforcecomparedwithallthethreefluidsatthesamepedalforce.SubsequentpedalforcesappliedasshowninTable2gaveareductioninthebrakeforcewhensoapsolutionwasused.Theimplicationwasthatsoapsolutioncouldbeusedtoproduceahighpedalforcewithinaveryshorttime(about10-30min)andcanthereforebeusedincaseofemergency.FromTable2,itcanbeobservedthatforthesamepedalforceof117KNthesoapsolutiontransmittedthehighestamountofbrakeforcefollowedbythecleanfluid,lessdirtyfluidanddirtyfluidinthatorder.Thisimpliesthatincoldconditionusingservo,thesoapsolutionperformsbestfollowedbytheclean,lessdirtyanddirtyrespectively.Discbrakeinhotconditionwithservounit:Whentheexperimentwascarriedoutusingadiscbrakeunderthehotconditionswiththeintroductionofaservo,apedalforceof120kNgaveabrakeforceof0.95kNforcleanfluid,0.90kNforlessdirty,0.85kNforadirtyfluidand0.19KNforsoapsolution.Theresultcouldbeexplainthat,thecleanbrakefluidgavethehighestbrakeforcefollowbylessdirty,dirtyandsoapsolution.Itwasobservedthatthesoapsolutionperformpoorlyatthistimerecordingabrakeforceof0.19KNasshowninTable3.Discbrakeinhotconditionwithoutservo:Figure4showsaplotofdiscbrakeinhotconditionwithoutservounit.Itcanbeobservedthat,underhotconditionsforthediscbrakewithoutservo,thetrendisgenerallythesame.Thesoapsolutionperformedverybadlycomparewiththeotherfluids,unlikeitsperformanceundercoldconditions.Thismaybeduetoevaporationofthefluidmakingthefluidcompressible;asifairwasinthebrakingsystem.Generally,thecleanfluidperformedbestintermsoftransmissionofbrakeforcefollowedbythelessdirty,dirtyandsoapsolutioninthatorder.Discbrakewithairinsystemundercoldcondition:BrakingforceforthisexperimentwasgenerallylowascomparedwiththecasewhenairwasnottrappedinthesystemasshowninTable4.Whentheexperimentwasconductedwithapedalforceof165kN,brakingforceofTable4:ResultsofdiscbrakewithairinsystemundercoldconditionwithservoFig.5:Resultsofdiscbrakewithairinsystemunderhotconditionwithservo0.32kNsoapsolutionwasobtained,for0.37KNfordirty,0.28KNforlessdirtyand0.30kNforcleanfluid.ThisisinlinewithliteraturebecauseaccordingtoMudd(1972)thepresenceofairinthebrakingsystemmakesthesystemineffectivesincemuchofthedriverseffortwillbeusedtocompresstheairleavingverylittleforthebrakeapplication.Again,thesoapsolutiondidnotgivetheleastbrakingforcebecausewhenthesystemiscold,soapsolutioniseffectiveanditsdensityishighersincethereisnooccurrenceofevaporationofthesolution.Discbrakewithairinsystemunderhotcondition:TheFig.5showstheplotofagraphindicatingdiscbrakewithairinthesystemunderhotconditionclearlyshowsthat,whenapedalforceof152kNwasapplied,abrakeforceof1.11kNwasobtainedforclean,0.37kNforlessdirty,0.28kNfordirtyand0.26kNforsoapsolution.Itwasobservedthatthemaximumbrakeforcewasattainedwhenthefluidwascleanandontheintroductionofdirtyfluid,thebrakeforcereduceddrastically,thoughthepedalforcewasveryhighat152kNinthehotcondition.Soapsolutionprovidestheleastbrakeforcebecausetheaircontentinthesystemincreasesduetoevaporationandhencethepedalforcecompressesairratherthantransmittingpower.Asthesystemheatsup,theairinthesystemexpandstherebyreducingthebrakingefficiencywhichresultsinbrakefailure.CONCLUSIONThestudywasconductedusinganexperimentperformedonaThepraBrakeTestingEquipmenttochecktheefficiencyofthefourfluidsinthetransmissionofbrakingforces.Accordingtotheviscometertestshownthatthesoapsolutionappearstobethebestfluidasfaraslowviscosityandstabilityofviscositywithincreaseintemperatureisconcerned.However,itislesscompatiblewithotherfluids,difficulttomixeasilywithotherbrakefluidsandhasalowboilingpointwhichwillnotmakeitsuitabletobesubstitutedasacleanbrakefluid.Again,whenairistrappedinthebrakingsystem,whichresultsinthebrakefluidbeingcompressible,higherpedalforcewasneededtobeabletoproduceasignificantbrakingforce.Also,whenbrakesareoperatedunderhotconditionsitsefficiencyisreduced,afaultknownasbrakefadeoccursasaresultoftheheatingupofthebrakeswhichcreateslessfrictionalresistancebetweenrotatingdiscandthefrictionalpads.Finally,Soapsolutionwhenusedatcoldconditionproduceshighbrakingforcebutbecomeslesseffectiveafterprolonguseduetothepresenceofheatwhichevaporatesthesoapsolution.REFERENCESAfukaar,F.,K.Agyemang,W.AckaahandI.Mosi,2008.RoadtrafficcrashesinGhana,statistics2007.ConsultancyServiceReportforNationalRoadSafetyCommissionofGhana.Bird,R.,S.WrightandE.N.Light,1960.TransportPhenomena,GibrinePublishingCompany,Heinz,H.,1999.VehicleandEngineTechnology.2ndEdn.,Butterworth-HeinemannPublications,Nurumberg,pp:235-291Johnson,D.,B.SperandeiandR.Gilbert,2003.Analysisoftheflowthroughaventedautomotivebrakerotor.J.FluidsEng.,125:979-986.Mcphee,A.D.andD.A.Johnson,2007.Experimentalheattransferandflowanalysisofaventedbrakerotor.Int.J.ThermalSci.,47(4):458-467.译文：一个使用四个液体系统分析盘式制动器的制动效率的实验摘要当车辆加速时能量由发动机提供使汽车的速度增加。这部分能量会瞬间消耗在克服摩擦和牵引阻力,但大量的仍然是存储在车辆当中。根据亨氏(1999)这个运动的能量叫做动能并且当车辆移动和中型齿轮被选中时才会被观察到。车辆没有立即进行制动，相反，它为以后行驶长距离而变得平稳。在这种情况所储存的能量用于驱动所述车辆针对相对车辆的运动的阻力。依靠这些阻力来减缓车辆可能会导致许多问题，因此需要一个额外的以更快的速度将懂你呢转换为热能的阻力来进行制动，以减少车辆麦克菲和约翰逊（2007）的速度。这以更快的速度降低了车辆的行使速度，使车辆在最短的反应时间内进行制动。从约翰逊等人的观点来看。大多数汽车系统现在使用前刹车盘，但四轮盘式制动系统也是常见的盘式制动器，与车辆一同旋转的转子和在摩擦垫进行移动后产生摩擦力以进行制动。大多数的盘式制动器是使用浮动卡钳式。当制动器被应用并释放时，活塞将移动的内垫推出并通过滑动卡钳朝转子方向推压内垫。盘式制动器的是为了降低车辆的行驶速度或者进行制动。但为了保证乘客的安全，在车辆行驶过程中不能过分的使用。由于车辆的动力，为了使车辆制动盘式制动器必须吸收发动机的所有能量，这种能量必须被散发掉。在大多数车辆的盘式制动器中，能量通过摩擦被吸收，转化成热能并耗散到周围的空气中。随着能量被吸收，车辆速度减缓，换句话说，他的运动是滞后的。制动器还必须保证车辆顺利的停止在一条直线上。车辆的盘式制动器以最高的效率运行可能会减少因刹车失灵而导致的事故率，从而使生命财产得以保护，同时也保证了这些车内人员的正常的工作和生活而无须担心被卷入事故当中。在加纳提供事故数据中表明每年约1900的人在道路交通事故中死亡并且以上的交通事故中有40%发生在轿车、公共汽车和乘用卡车上。最为常见的是，一些一些涉及交通事故的车辆如小型汽车已经归因于刹车盘刹车失灵。由于大多数的加纳司机将肥皂溶液等肮脏的制动液用来替代原制动系统制动液以达到讨厌的目的，所以我们对这些制动液的粘度进行测试，特别是皂液。这项研究是一个更大的工作的一部分，旨在探讨和寻找盘式制动器制动故障的原因，还要检查制动力的传递中使用的四种不同类型的液体的效率。这项实验研究在使用清洁、不清洁、肮脏和肥皂水四种不同的溶液在制动系统中的能产生的最大制动力。制动系统在冷空气或热空气或没有空气的情况下，产生的制动力也是不一样的。盘式制动器盘式制动器由一个被连接到轮毂凸缘的外露盘组成；两个摩擦片被压在这个圆盘上，以使制动作用。图1a显示从车轮组件分离的汽车制动系统，更好的显示出摩擦片和外露盘是分开安装的在滑动接触中。可以看出，典型的盘式制动器系统和制动盘的制动盘总成是完全不引人注目的。图1b显示磁盘示意图的形式和垫在滑动接触组件。(b)图一：盘式制动器该垫是通过在一个圆筒中形成的咦个固定在轮轴上的固定卡钳里的液压活塞杆工作而移动的。当液压压在固定的卡钳上时，活塞移动时，该动作将摩擦盘与旋转的铸铁盘接触。摩擦盘上的垫进行夹持的动作产生了一个缓滞的作用并且将运动的能量转换的热量传递到圆盘上。大圆盘的一部分暴露在空气中,因此很容易散热,所以制动系统可以在发生很严重的失灵之前被连续使用。由于摩擦片以一个正确的角度移动到圆盘，所以任何下降的摩擦值不影响施加到垫的力。所以这种类型的制动器对于热并不是那么的不敏感。盘式制动器的开发研究为降低制动失灵问题。制动失灵发生时,司机必须花费更大的力并且在极端情况下,无法将车辆停止。在盘式制动器作用时，没有任何设备去帮助司机在旋转的制动盘上去实现多余的制动。盘式制动器需要一个更大的踏板压力，液压制动系统使用一个良好的质量制动液在其操作以达到这个压力要求。液压制动系统中所用的流体是一种植物油，具有一定的添加剂。据伦尼说，良好的制动液应具有以下要求，低粘度、高沸点、与橡胶部件的相容性、润滑性能、耐化学老化性及与其它流体的相容性。无论何时，越多越好。加纳司机有时将一些如低劣的制动液、脏的流体甚至肥皂水作为制动液以代替原来的制动液.。这项研究中，也将探讨这些清洁，肮脏，不洁和皂水的制动液将有更好的粘度，更高的沸点和更少的制动力。材料与方法本研究是采用用粘度计和thepra通用汽车制动试验台检测四种液体在制动力的传输效率的实验设计。图二：乌氏粘度计测定液体的粘度实验室分析：在夸梅恩克鲁玛科技大学进行（KNUST）热力学实验室进行四种不同的液体的粘度测试。分别是：液体清洁制动液、稍微肮脏的制动液、肮脏的制动液和作为解决方案的皂液。有必要找出不同质量的制动液的粘度对制动效率的影响，并找出这些与制动故障的发生之间是否存在相关性。在各种流体粘度测试：在图2的红木粘度计对四种不同种类的流体进行粘度测试。该装置包括一个装着测试所用流体的垂直圆柱体，圆柱体在一个允许流体通过的一个位于中心的校准孔气缸底座的下面。当不使用时，该孔由球阀关闭。这个液压缸被一个在试验中用来保持润滑的水套紧紧密封着，用一个本生灯的火焰进行加热，用来测试一个温度。水套温度计被安装在一个有旋转叶片的搅拌器里进行使用。用于测试各种粘度的流体的方法：为了测试流体的粘度，在用孔球阀的位置上填充了水夹套。流体注入到气缸的水平的位置。一个50毫升的测量瓶被放置在中央的孔下。水被轻轻地搅拌，直到水和液体温度计显示的温度是一样的（室温，30ºC）。记录温度，然后球阀浮起，用一个秒表来测量液体流入这个50毫升的测量瓶所用的时间。实验重复多次，每次试验温度最低10ºC最高90º，记录四种不同的流体的所有数据，如表1所示。表1：粘度试验汽车制动检测设备：普遍的汽车制动检测设备是这样一种结构，驱动部分是制动盘插入到电机轴。制动锚板和制动钳通过一个连杆连接紧固到一个法兰上。测量制动力并显示在数字显示器上。各个单元被插入到紧固在两侧的双跨框架中。测试设备中使用的所有制动部件都是原车部件。踏板力在制动主缸驱动连杆测量并显示在数字显示器上。实验结果与讨论：使用公式计算各种粘度的值：V=HFρGD32hfv使用公式计算各种粘度的值：V=HFρGD32hfvV：粘度hf：毛细管高度ρ：流体的密度g:由于重力加速度D：孔的直径V:速度图三：流体粘度-温度关系从图3中可以看出脏的流体具有最高的粘度，其次是较低的流体，清洁液和肥皂溶液。从图2所示的结果和表1所示的粘度测试中，显示随着温度的升高肥皂溶液是粘度和粘度稳定性最好的流体。然而，它与其它液体不兼容，很难与其他制动液混合，并且有一个低沸点，这将不适合作为清洗制动液的替代品。清洁制动液的粘度和粘度随温度升高而增加。另一方面，它满足了表1中显示的一个良好的流体制动系统中应具有的所有要求，也满足了根据马德（1972）和纳尼等人（1