会员注册 | 登录 | 微信快捷登录 支付宝快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

外文翻译--柴油发动机工作原理.doc外文翻译--柴油发动机工作原理.doc -- 5 元

宽屏显示 收藏 分享

资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您

无锡太湖学院2009届本科生毕业设计(论文)翻译1Adieselengineworks【Abstract】Inadieselenginecylinder,thepistoninthepartoftheworkcycleofcompressedgas,andinanotherpartoftheworkcycleofthecombustiongasmixturewithinthecylindersothepistontopsurfaceexpansionhighpressureabout116120Kgf/cm2underhightemperatureabout569°Cgasrole,andthepressurethroughthepistonpin,connectingrodtothecrankshaft.Canbeseenthatthepistonisalongtimeunderhightemperatureandhighpressureincontinuousreciprocatingmotionoftheload,itsloadandworkingconditionswereappalling.Duringthedesignprocessofthepistonwillbedesignedtoensurelongtermstabilityoftheworkpiston.ThedesignoftheworkdonebyabriefintroductionasfollowsDieselEnginePiston180Creasonableprocessingtechnologyisimportant,theroleofpartsandtechnologyprogramanalysis,preparationofroughformandprocessmanufacturingline,throughtheanalysis,comparison,useoftherelativeconcentrationofprocessingprograms,andultimatelymorereasonabletodeterminethemechanicallineprocessing.Thedevelopmentprocessofroughlinethemainconsideration,finishingarrangements,choiceofprocessingmethods,centralizedanddecentralizedprocesses,suchasprocessingtheorderrequirements.Thendeterminetheallowance,processsize,aftertheanalysisofthecharacteristicsoftheprocess,selecttheappropriateprocessingequipmentandtechnicalequipment.Calculatedlookuptabletodeterminethenextmajorpistoncuttingprocessandthemappingofprocessescard,thedesignofthefinalfixture.Fixturedesign,itisnecessarytotakevariousaspectsintoaccount,thestrictrequirementsofthefixtureadirectimpactonthesurfaceoftheworkpieceprocessingpositionaccuracy.Therefore,themachinetooldesignfixturedesignisanimportanttaskistheprocessingofoneofthemostactive.Duringthegraduationprojectinaspeciallydesignedpositioningaccuracy,simplestructureandeasytouseprecisionpinholeboringjig.KeywordsPistonTechnologyprocessingequipmentcuttingFixtureAnytypeofmachinethatobtainsmechanicalenergydirectlyfromtheexpenditureofthechemicalenergyoffuelburnedinacombustionchamberthatisanintegralpartoftheengine.FourprincipaltypesofinternalcombustionenginesareingeneralusetheOttocycleengine,thedieselengine,therotaryengine,andthegasturbine.Forthevarioustypesofenginesemployingtheprincipleofjetpropulsion,seeJetPropulsionRocket.TheOttocycleengine,namedafteritsinventor,theGermantechnicianNikolausAugustOtto,isthefamiliargasolineengineusedinautomobilesandairplanesthedieselengine,namedaftertheFrenchbornGermanengineerRudolfChristianKarlDiesel,operatesonadifferentprincipleandusuallyusesoilasafuel.Itisemployedinelectricgeneratingandmarinepowerplants,intrucksandbuses,andinsomeautomobiles.BothOttocycleanddieselenginesaremanufacturedin无锡太湖学院2009届本科生毕业设计(论文)翻译2twostrokeandfourstrokecyclemodels.TheessentialpartsofOttocycleanddieselenginesarethesame.Thecombustionchamberconsistsofacylinder,usuallyfixed,thatisclosedatoneendandinwhichaclosefittingpistonslides.Theinandoutmotionofthepistonvariesthevolumeofthechamberbetweentheinnerfaceofthepistonandtheclosedendofthecylinder.Theouterfaceofthepistonisattachedtoacrankshaftbyaconnectingrod.Thecrankshafttransformsthereciprocatingmotionofthepistonintorotarymotion.Inmulticylinderedenginesthecrankshafthasoneoffsetportion,calledacrankpin,foreachconnectingrod,sothatthepowerfromeachcylinderisappliedtothecrankshaftattheappropriatepointinitsrotation.Crankshaftshaveheavyflywheelsandcounterweights,whichbytheirinertiaminimizeirregularityinthemotionoftheshaft.Anenginemayhavefrom1toasmanyas28cylinders.Thefuelsupplysystemofaninternalcombustionengineconsistsofatank,afuelpump,andadeviceforvaporizingoratomizingtheliquidfuel.InOttocycleenginesthisdeviceiseitheracarburetoror,morerecently,afuelinjectionsystem.Inmostengineswithacarburetor,vaporizedfuelisconveyedtothecylindersthroughabranchedpipecalledtheintakemanifoldand,inmanyengines,asimilarexhaustmanifoldisprovidedtocarryoffthegasesproducedbycombustion.Thefuelisadmittedtoeachcylinderandthewastegasesexhaustedthroughmechanicallyoperatedpoppetvalvesorsleevevalves.Thevalvesarenormallyheldclosedbythepressureofspringsandareopenedatthepropertimeduringtheoperatingcyclebycamsonarotatingcamshaftthatisgearedtothecrankshaft.Bythe1980smoresophisticatedfuelinjectionsystems,alsousedindieselengines,hadlargelyreplacedthistraditionalmethodofsupplyingthepropermixofairandfuel.Inengineswithfuelinjection,amechanicallyorelectronicallycontrolledmonitoringsysteminjectstheappropriateamountofgasdirectlyintothecylinderorinletvalveattheappropriatetime.Thegasvaporizesasitentersthecylinder.Thissystemismorefuelefficientthanthecarburetorandproduceslesspollution.Inallenginessomemeansofignitingthefuelinthecylindermustbeprovided.Forexample,theignitionsystemofOttocycleenginesdescribedbelowconsistsofasourceoflowvoltage,directcurrentelectricitythatisconnectedtotheprimaryofatransformercalledanignitioncoil.Thecurrentisinterruptedmanytimesasecondbyanautomaticswitchcalledthetimer.Thepulsationsofthecurrentintheprimaryinduceapulsating,highvoltagecurrentinthesecondary.Thehighvoltagecurrentisledtoeachcylinderinturnbyarotaryswitchcalledthedistributor.Theactualignitiondeviceisthesparkplug,aninsulatedconductorsetinthewallortopofeachcylinder.Attheinnerendofthesparkplugisasmallgapbetween无锡太湖学院2009届本科生毕业设计(论文)翻译3twowires.Thehighvoltagecurrentarcsacrossthisgap,yieldingthesparkthatignitesthefuelmixtureinthecylinder.Becauseoftheheatofcombustion,allenginesmustbeequippedwithsometypeofcoolingsystem.Someaircraftandautomobileengines,smallstationaryengines,andoutboardmotorsforboatsarecooledbyair.Inthissystemtheoutsidesurfacesofthecylinderareshapedinaseriesofradiatingfinswithalargeareaofmetaltoradiateheatfromthecylinder.Otherenginesarewatercooledandhavetheircylindersenclosedinanexternalwaterjacket.Inautomobiles,wateriscirculatedthroughthejacketbymeansofawaterpumpandcooledbypassingthroughthefinnedcoilsofaradiator.Someautomobileenginesarealsoaircooled,andinmarineenginesseawaterisusedforcooling.Unlikesteamenginesandturbines,internalcombustionenginesdevelopnotorquewhenstarting,andthereforeprovisionmustbemadeforturningthecrankshaftsothatthecycleofoperationcanbegin.Automobileenginesarenormallystartedbymeansofanelectricmotororstarterthatisgearedtothecrankshaftwithaclutchthatautomaticallydisengagesthemotoraftertheenginehasstarted.Smallenginesaresometimesstartedmanuallybyturningthecrankshaftwithacrankorbypullingaropewoundseveraltimesaroundtheflywheel.Methodsofstartinglargeenginesincludetheinertiastarter,whichconsistsofaflywheelthatisrotatedbyhandorbymeansofanelectricmotoruntilitskineticenergyissufficienttoturnthecrankshaft,andtheexplosivestarter,whichemploystheexplosionofablankcartridgetodriveaturbinewheelthatiscoupledtotheengine.Theinertiaandexplosivestartersarechieflyusedtostartairplaneengines.TheordinaryOttocycleengineisafourstrokeenginethatis,inacompletepowercycle,itspistonsmakefourstrokes,twotowardtheheadclosedheadofthecylinderandtwoawayfromthehead.Duringthefirststrokeofthecycle,thepistonmovesawayfromthecylinderheadwhilesimultaneouslytheintakevalveisopened.Themotionofthepistonduringthisstrokesucksaquantityofafuelandairmixtureintothecombustionchamber.Duringthenextstroke,thepistonmovestowardthecylinderheadandcompressesthefuelmixtureinthecombustionchamber.Atthemomentwhenthepistonreachestheendofthisstrokeandthevolumeofthecombustionchamberisataminimum,thefuelmixtureisignitedbythesparkplugandburns,expandingandexertingapressureonthepiston,whichisthendrivenawayfromthecylinderheadinthethirdstroke.Duringthefinalstroke,theexhaustvalveisopenedandthepistonmovestowardthecylinderhead,drivingtheexhaustgasesoutofthecombustionchamberandleavingthecylinderreadytorepeatthecycle.TheefficiencyofamodernOttocycleengineislimitedbyanumberoffactors,includinglossesbycoolingandbyfriction.Ingeneral,theefficiencyofsuchenginesis无锡太湖学院2009届本科生毕业设计(论文)翻译4determinedbythecompressionratiooftheengine.Thecompressionratiotheratiobetweenthemaximumandminimumvolumesofthecombustionchamberisusuallyabout8to1or10to1inmostmodernOttocycleengines.Highercompressionratios,uptoabout15to1,witharesultingincreaseofefficiency,arepossiblewiththeuseofhighoctaneantiknockfuels.TheefficienciesofgoodmodernOttocycleenginesrangebetween20and25percentinotherwords,onlythispercentageoftheheatenergyofthefuelistransformedintomechanicalenergyTheoretically,thedieselcyclediffersfromtheOttocycleinthatcombustiontakesplaceatconstantvolumeratherthanatconstantpressure.MostdieselsarealsofourstrokeenginesbuttheyoperatedifferentlythanthefourstrokeOttocycleengines.Thefirst,orsuction,strokedrawsair,butnofuel,intothecombustionchamberthroughanintakevalve.Onthesecond,orcompression,stroketheairiscompressedtoasmallfractionofitsformervolumeandisheatedtoapproximately440°Capproximately820°Fbythiscompression.Attheendofthecompressionstroke,vaporizedfuelisinjectedintothecombustionchamberandburnsinstantlybecauseofthehightemperatureoftheairinthechamber.Somedieselshaveauxiliaryelectricalignitionsystemstoignitethefuelwhentheenginestartsanduntilitwarmsup.Thiscombustiondrivesthepistonbackonthethird,orpower,strokeofthecycle.Thefourthstroke,asintheOttocycleengine,isanexhauststroke.Theefficiencyofthedieselengine,whichisingeneralgovernedbythesamefactorsthatcontroltheefficiencyofOttocycleengines,isinherentlygreaterthanthatofanyOttocycleengineandinactualenginestodayisslightlymorethan40percent.Dieselsare,ingeneral,slowspeedengineswithcrankshaftspeedsof100to750revolutionsperminuterpmascomparedto2500to5000rpmfortypicalOttocycleengines.Sometypesofdiesel,however,havespeedsupto2000rpm.Becausedieselsusecompressionratiosof14ormoreto1,theyaregenerallymoreheavilybuiltthanOttocycleengines,butthisdisadvantageiscounterbalancedbytheirgreaterefficiencyandthefactthattheycanbeoperatedonlessexpensivefueloils.BysuitabledesignitispossibletooperateanOttocycleordieselasatwostrokeortwocycleenginewithapowerstrokeeveryotherstrokeofthepistoninsteadofonceeveryfourstrokes.Thepowerofatwostrokeengineisusuallydoublethatofafourstrokeengineofcomparablesize.Thegeneralprincipleofthetwostrokeengineistoshortentheperiodsinwhichfuelisintroducedtothecombustionchamberandinwhichthespentgasesareexhaustedtoasmallfractionofthedurationofastrokeinsteadofallowingeachoftheseoperationstooccupyafullstroke.Inthesimplesttypeoftwostrokeengine,thepoppetvalvesarereplacedbysleeve
编号:201311171636207345    大小:55.00KB    格式:DOC    上传时间:2013-11-17
  【编辑】
5
关 键 词:
教育专区 外文翻译 精品文档 外文翻译
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

当前资源信息

4.0
 
(2人评价)
浏览:12次
英文资料库上传于2013-11-17

官方联系方式

客服手机:13961746681   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

相关资源

相关搜索

教育专区   外文翻译   精品文档   外文翻译  
关于我们 - 网站声明 - 网站地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5