盤式制動器中英文對照外文翻譯文獻

PAGEPAGE20中英文對照外文翻譯文獻(文檔含英文原文和中文翻譯)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.譯文：一個使用四個液體系統分析盤式制動器的制動效率的實驗摘要當車輛加速時能量由發動機提供使汽車的速度增加。這部分能量會瞬間消耗在克服摩擦和牽引阻力,但大量的仍然是存儲在車輛當中。根據亨氏(1999)這個運動的能量叫做動能并且當車輛移動和中型齒輪被選中時才會被觀察到。車輛沒有立即進行制動，相反，它為以后行駛長距離而變得平穩。在這種情況所儲存的能量用于驅動所述車輛針對相對車輛的運動的阻力。依靠這些阻力來減緩車輛可能會導致許多問題，因此需要一個額外的以更快的速度將懂你呢轉換為熱能的阻力來進行制動，以減少車輛麥克菲和約翰遜（2007）的速度。這以更快的速度降低了車輛的行使速度，使車輛在最短的反應時間內進行制動。從約翰遜等人的觀點來看。大多數汽車系統現在使用前剎車盤，但四輪盤式制動系統也是常見的盤式制動器，與車輛一同旋轉的轉子和在摩擦墊進行移動后產生摩擦力以進行制動。大多數的盤式制動器是使用浮動卡鉗式。當制動器被應用并釋放時，活塞將移動的內墊推出并通過滑動卡鉗朝轉子方向推壓內墊。盤式制動器的是為了降低車輛的行駛速度或者進行制動。但為了保證乘客的安全，在車輛行駛過程中不能過分的使用。由于車輛的動力，為了使車輛制動盤式制動器必須吸收發動機的所有能量，這種能量必須被散發掉。在大多數車輛的盤式制動器中，能量通過摩擦被吸收，轉化成熱能并耗散到周圍的空氣中。隨著能量被吸收，車輛速度減緩，換句話說，他的運動是滯后的。制動器還必須保證車輛順利的停止在一條直線上。車輛的盤式制動器以最高的效率運行可能會減少因剎車失靈而導致的事故率，從而使生命財產得以保護，同時也保證了這些車內人員的正常的工作和生活而無須擔心被卷入事故當中。在加納提供事故數據中表明每年約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%發生在轎車、公共汽車和乘用卡車上。最為常見的是，一些一些涉及交通事故的車輛如小型汽車已經歸因于剎車盤剎車失靈。由于大多數的加納司機將肥皂溶液等骯臟的制動液用來替代原制動系統制動液以達到討厭的目的，所以我們對這些制動液的粘度進行測試，特別是皂液。這項研究是一個更大的工作的一部分，旨在探討和尋找盤式制動器制動故障的原因，還要檢查制動力的傳遞中使用的四種不同類型的液體的效率。這項實驗研究在使用清潔、不清潔、骯臟和肥皂水四種不同的溶液在制動系統中的能產生的最大制動力。制動系統在冷空氣或熱空氣或沒有空氣的情況下，產生的制動力也是不一樣的。盤式制動器盤式制動器由一個被連接到輪轂凸緣的外露盤組成；兩個摩擦片被壓在這個圓盤上，以使制動作用。圖1a顯示從車輪組件分離的汽車制動系統，更好的顯示出摩擦片和外露盤是分開安裝的在滑動接觸中。可以看出，典型的盤式制動器系統和制動盤的制動盤總成是完全不引人注目的。圖1b顯示磁盤示意圖的形式和墊在滑動接觸組件。(b)圖一：盤式制動器該墊是通過在一個圓筒中形成的咦個固定在輪軸上的固定卡鉗里的液壓活塞桿工作而移動的。當液壓壓在固定的卡鉗上時，活塞移動時，該動作將摩擦盤與旋轉的鑄鐵盤接觸。摩擦盤上的墊進行夾持的動作產生了一個緩滯的作用并且將運動的能量轉換的熱量傳遞到圓盤上。大圓盤的一部分暴露在空氣中,因此很容易散熱,所以制動系統可以在發生很嚴重的失靈之前被連續使用。由于摩擦片以一個正確的角度移動到圓盤，所以任何下降的摩擦值不影響施加到墊的力。所以這種類型的制動器對于熱并不是那么的不敏感。盤式制動器的開發研究為降低制動失靈問題。制動失靈發生時,司機必須花費更大的力并且在極端情況下,無法將車輛停止。在盤式制動器作用時，沒有任何設備去幫助司機在旋轉的制動盤上去實現多余的制動。盤式制動器需要一個更大的踏板壓力，液壓制動系統使用一個良好的質量制動液在其操作以達到這個壓力要求。液壓制動系統中所用的流體是一種植物油，具有一定的添加劑。據倫尼說，良好的制動液應具有以下要求，低粘度、高沸點、與橡膠部件的相容性、潤滑性能、耐化學老化性及與其它流體的相容性。無論何時，越多越好。加納司機有時將一些如低劣的制動液、臟的流體甚至肥皂水作為制動液以代替原來的制動液.。這項研究中，也將探討這些清潔，骯臟，不潔和皂水的制動液將有更好的粘度，更高的沸點和更少的制動力。材料與方法本研究是采用用粘度計和thepra通用汽車制動試驗臺檢測四種液體在制動力的傳輸效率的實驗設計。圖二：烏氏粘度計測定液體的粘度實驗室分析：在夸梅恩克魯瑪科技大學進行（KNUST）熱力學實驗室進行四種不同的液體的粘度測試。分別是：液體清潔制動液、稍微骯臟的制動液、骯臟的制動液和作為解決方案的皂液。有必要找出不同質量的制動液的粘度對制動效率的影響，并找出這些與制動故障的發生之間是否存在相關性。在各種流體粘度測試：在圖2的紅木粘度計對四種不同種類的流體進行粘度測試。該裝置包括一個裝著測試所用流體的垂直圓柱體，圓柱體在一個允許流體通過的一個位于中心的校準孔氣缸底座的下面。當不使用時，該孔由球閥關閉。這個液壓缸被一個在試驗中用來保持潤滑的水套緊緊密封著，用一個本生燈的火焰進行加熱，用來測試一個溫度。水套溫度計被安裝在一個有旋轉葉片的攪拌器里進行使用。用于測試各種粘度的流體的方法：為了測試流體的粘度，在用孔球閥的位置上填充了水夾套。流體注入到氣缸的水平的位置。一個50毫升的測量瓶被放置在中央的孔下。水被輕輕地攪拌，直到水和液體溫度計顯示的溫度是一樣的（室溫，30oC）。記錄溫度，然后球閥浮起，用一個秒表來測量液體流入這個50毫升的測量瓶所用的時間。實驗重復多次，每次試驗溫度最低10oC最高90o，記錄四種不同的流體的所有數據，如表1所示。表1：粘度試驗汽車制動檢測設備：普遍的汽車制動檢測設備是這樣一種結構，驅動部分是制動盤插入到電機軸。制動錨板和制動鉗通過一個連桿連接緊固到一個法蘭上。測量制動力并顯示在數字顯示器上。各個單元被插入到緊固在兩側的雙跨框架中。測試設備中使用的所有制動部件都是原車部件。踏板力在制動主缸驅動連桿測量并顯示在數字顯示器上。實驗結果與討論：使用公式計算各種粘度的值：V=HFρGD32hfv使用公式計算各種粘度的值：V=HFρGD32hfvV：粘度hf：毛細管高度ρ：流體的密度g:由于重力加速度D：孔的直徑V:速度圖三：流體粘度-溫度關系從圖3中可以看出臟的流體具有最高的粘度，其次是較低的流體，清潔液和肥皂溶液。從圖2所示的結果和表1所示的粘度測試中，顯示隨著溫度的升高肥皂溶液是粘度和粘度穩定性最好的流體。然而，它與其它液體不兼容，很難與其他制動液混合，并且有一個低沸點，這將不適合作為清洗制動液的替代品。清潔制動液的粘度和粘度隨溫度升高而增加。另一方面，它滿足了表1中顯示的一個良好的流體制動系統中應具有的所有要求，也滿足了根據馬德（1972）和納尼等人（1