车辆工程毕设英文翻译Word格式.docx

车辆工程毕设英文翻译Word格式.docx

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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