车辆工程毕设英文翻译.docx
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车辆工程毕设英文翻译
Withtherapiddevelopmentofautomobileindustry,thereiscomfortandvehiclevibrationandnoisecontrolofmoreandmorestringentrequirements.Accordingtorelevantdatashowsthat70percentofthecitynoisefromthetrafficnoise,andtrafficnoiseismainlycarnoise.Itisseriouslypollutingtheurbanenvironment,affectingpeople'slife,workandhealth.Sonoisecontrolisnotonlyrelatedtocomfort,butalsorelatedtoenvironmentalprotection.However,allalsofromthevibrationnoise,vibrationcancausecertainpartsoftheearlyfatiguedamage,therebyreducingtheservicelifeofmotorvehicles;excessivenoisecandamagehearingthedriverwillenabletherapiddriverfatigue,thusdrivingsecurityconstitutesagravethreat.Sonoisecontrol,isalsorelatedtomotorvehicledurabilityandsafety.Thusvibration,noiseandcomfortarethethreecloselyrelated,itisnecessarytoreducevibration,reducenoise,butalsoimproveridecomfort,andensuretheproducteconomy,vehiclenoisecontrolinthestandardrange.
Onetypeofnoisearisingfromcarnoisearethemainfactorsofairpower,mechanicaldrive,theelectromagneticthreeparts.Fromthestructurecanbedividedintotheengine(ie,combustionnoise),thechassisnoise(ie,powertrainnoise,allcomponentsconnectedwiththenoise),electricalequipment,noise(coolingfannoise,carnoisegenerator),bodynoise(suchasbodystructure,shapeandattachmentinstallationunreasonablenoise).Oneoftheenginenoiseaccountedformorethanhalfofmotorvehiclenoise,includingnoiseandbodyintakenoise(suchasenginevibration,therotationalaxisValve,Jin,doorswitches,suchasexhaustnoise).Thereforetheenginevibration,noisereductionhasbecomeakeyautomotivenoisecontrol.
Inaddition,automobiletiresathighspeed,itwillalsocausemorenoise.Thisisbecauseofthetireatthegroundflows,thepatternislocatedintheairbygroundtankandre-extrusionprocesscausedbyinhalinggaspumpsound,aswellastreadpatternswithpercussivesoundoftheroad.
2noiserequirementsofregulationsinEurope,fromOctober1996onwards,theexternalbus77dBAnoisemustbereducedto74dBA,noisewasreducedbyhalfenergy,theendofthecenturyfurtherreducedto71dBA.Japan'slawsandregulations,smallcarinthenextdecadetocontrolnoisestandardsatthefollowing76dBA.Anumberofdomesticcitiesarealsoplanningtotraffictrunklinesin2010tocontrolnoiseattheaverageoflessthan70dBA.Accordingtothedomesticcurrentdataindicatethatthedomesticvalueofbusnoisepermitshallnotexceed82dBA,lighttrucksfor83.5dBA.Thisshowsthatourcountryinthevehiclenoisecontrolwillhavetomakedo.
3noiseassessmentnoiseevaluationmainlyreferstothecar,outsidenoiseandvibrationadaptivevalue.Evaluationmethodscanbedividedintosubjectiveevaluationandobjectiveevaluation.Subjectiveassessmentoftheimpactofvehiclenoiseisamajorfactorincomfort,loudnessanduncertainties,suchassemanticdifferentialmethodcanbeusedforsubjectiveevaluation.Atanobjectiveevaluation,canbeusedPCNMnoisemeasuringdeviceformeasuringtestanalysis;additionsimulationtechnologyinthefiniteelementmethod(FEM)andboundaryelementmethod(BEM)hasbeenwidelyapplied.
4noisecontrolnoisegenerationanddisseminationinaccordancewiththemechanismofnoisecontroltechnologycanbeputintothefollowingthreecategories:
First,thecontrolofnoisesources,aretworoutesoftransmissionofnoisecontrol,noisethreerecipientsareprotected.Oneofthecontrolofnoisesourcesarethemostfundamental,themostdirectmeasures,includingnoisereductiontoreducetheexcitingforceandtheenginepartsoftheexcitingforceresponse,whichmeanstransformationofacousticsourcelocaloscillator.However,itisdifficulttocontrolnoisesourceswhennecessaryintherouteoftransmissionofnoisetotakemeasures,suchassoundabsorption,soundinsulation,noisereduction,vibrationandvibrationisolationmeasures.Motorvehiclesandvehiclevibrationandnoisereductionlevelofpower,economy,reliabilityandstrength,stiffness,quality,manufacturingcostsandusearecloselyrelated.
4.1enginetoreducevibrationandnoiseoftheenginenoiseisthefocusofautomotivenoisecontrol.Enginevibrationandnoisearegeneratedatsource.Enginenoiseisfromfuelcombustion,valvebodies,gearsandpistontimingnoisepercussionsynthesis.
(1)ontologyenginenoise
Lowerenginenoisewillbeontologicaltransformationoflocaloscillatorsoundsources,includingmethodssuchasfiniteelementmethodanalysisanddesignengines,selectionofsoftcombustionprocess,improvethestructureofthebodystiffness,withtheuseoftightspace,reducenoisecylindercover.Forexampleintheoilpanonanadditionalstiffeneranddiaphragmtoimprovethestiffnessofoilpantoreducevibrationandnoise.Inaddition,givetheengineTudampingmaterialisaneffectiveapproach.Dampingmaterialscankineticenergyintothermalenergy.Todealwiththeprincipleofdampingisadampingmaterialsandcomponentsintoitsvibrationalenergytoconsume.Ithasthefollowingstructure:
Freedomdampinglayerstructure,andspacingoffreelydampinglayerstructure,andconstraineddampinglayerstructureandspacingofconstraineddampinglayer.Itisclearthattheadoptionofadecreaseofresonanceamplitudeandacceleratedthedecayoffreevibration,reducingthevariouspartsoftheChuan-Zhencapacity,anincreaseofpartsatorabovethecriticalfrequencyofvibrationisolationcapacity.
Atpresent,somecountrieshavedesignedanengineexpertsactivevibrationisolationsystemtoreduceenginevibration,inordertoachievethepurposeofnoisereduction.
(2)intakenoise
Engineintakenoiseisoneofthemainnoisesource,theDepartmentoftheenginenoiseofairpower,withtheenginespeedincreasestostrengthen.Non-superchargedengineintakenoisemajorcomponents,includingthecyclicalpressurefluctuationnoise,vortexnoise,thecylinderoftheHelmholtzresonancenoise.Dieselenginesuperchargerintakenoisemainlyfromtheturbochargercompressor.TwostrokeenginenoisefromtheRootspump.Inthisregard,themosteffectivemethodistheuseofintakemuffler.Thereisaresistivetypemuffler(absorptiontype),resistantmuffler(expansiontype,resonancetype,interference-typeandporousdecentralized)andthecompositemuffler.Tocombinewiththeairfilter(thatisintheairfilteronanadditionalresonancechamberandsound-absorbingmaterial,forexample,typeR3238)hasbecomethemosteffectiveintakemuffler,mufflervolumeofmorethan20dBA.
4.2ChassisNoise
(1)Departmentofexhaustnoise
Departmentofthechassisexhaustnoiseisthemainnoisesources,mainlyfromtheexhaustpressurepulsationnoise,airflowthroughthevalveseatwhenissuedbyeddycurrentnoise,becauseofboundarylayerairflowdisturbancecausedbynoiseandexhaustOfficejetnoisecomposition.
Designedtooptimizetheperformanceofagoodmuffler,toreducecarnoiseareoneoftheimportantmeans.Optimizedesignmethodhasacousticfiniteelementmethodandacousticboundaryelementmethod,butisstillinitsinfancy.Mufflertoavoidthetransmissioncharacteristicsandvibrationcharacteristicsofcoupledmufflersaredesignedtobefocusedonsolvingaproblem.Secondly,toreduceexhaustnoiseandimprovepowerisalsoapairofcontradictions,becausetoreduceexhaustnoiseandlowerexhaustbackpressureonthedesignoftheexhaustpipehasadiameterofconflictingdemands,theformerrequiresasmallerdiameter,whichisopposite.Inthisregard,theuseofparallelflowpathofthedualfunctionmuffler,atreducedairpressureandreducenoisetobeeffective.Inaddition,theengineexhaustmanifoldtothemufflerinletpipesection,theuseofflexiblepipevibration,noisereductioneffectcanbereducedtoabout7dBA.
(2)powertrainnoise
Powertrainnoisefromthevibrationcausedby变速齿轮meshingandrotatingshaftvibration.Generalmeasurestakenare:
First,chooselow-noisetransmission,engineandgearboxaretwoandthemainreducer,suchasrearaxleandchassiscomponentsforflexiblerubberpadconnections,soastoachievethepurposeofisolation;arethree-axisrotationalcontrolbalancedegrees,toreducetorsionalvibration.
4.3Electricequipmentnoise
(1)coolingfannoise
Coolingfannoisehappeneddevicesaresubjecttowindretainingring,waterpump,radiatorandtransmission,butthenoisegenerateddependsprimarilyonthechassis.
(2)automobilegeneratornoise
Automotivegeneratornoisedependsontheeffectsofavarietyofsources,thesesourceshavemagnetsource,mechanicalandairpowersource.Noiseleveldependsonthegeneratormagneticstructureandventilationsystems,aswellasgeneratorsprecisionmanufacturingandassembly.
4.4BodyNoise
Asthespeedincreased,thebodywillbemoreandmorenoise,andairpowerarethemaincausesofnoise.Therefore,thefollowingprogramstoimprovethebodynoise:
First,tostreamlinethedesignofthebody,achieveasmoothtransition;twoareinbetweenthebodyandframecomponentstoadoptaflexibleconnection;threeinteriorissoftened,suchasInnerMongoliaattheroofandbodyskintheuseofsound-absorbingmaterial.
Inaddition,thecarathighspeedwhenthetireisalsoasourceofnoise.RealvehicleInertinglinemethodhasbeenmeasured:
TireTreadgreater,thenthegreaterthenoise.Inaddition,thetiretreadwiththenoisegeneratedalsohaveagreatrelationship,thereisareasonablechoiceofthepatternofsteelcordforradialtirestoreducet