NewWordsandExpressionsgear[g??(r)]n.裝置，機構(gòu)bedplate['bedple?t]n.機座，底座frame[fre?m]n.機架，框架crosshead['kr?shed]n.十字頭navigation[?n?v??ge??n]n.航行weld[weld]v.焊接bolt[b??lt]n.螺栓secure[s??kj??(r)]v.固定NewWordsandExpressionstransverse[?tr?nzv?:s;?tr?nsv??s]a.橫向的longitudinal[?l??g??tju:d?nl;?l?nd???tju?d?nl]a.縱向的chock[t??k]n.側(cè)塊，楔型塊girder[?g?:d?(r)]n.梁shell[?el]n.軸瓦lined[la?nd]a.內(nèi)襯的stud[st?d]n.雙頭螺栓nut[n?t]n.螺母NewWordsandExpressionshydraulic[ha??dr?:l?k]a.液壓的column[?k?l?m]n.機架crankcase['kr??kke?s]n.曲柄箱，曲軸箱camshaft[?k?m?ɑ:ft]n.凸輪軸deformation[?di?f???me??n]n.變形vibration[va??bre??n]n.振動lubrication[?lu?br??ke??n]n.潤滑（油）oblique[??bli:k]a.斜的NewWordsandExpressionsdeposit[d??p?z?t]n.堆積物，沉淀物topland[?t?pl?nd]n.頂岸fitting[?fiti?]n.附件cylindercover

氣缸蓋connectingrod

連桿mainbearingcap

主軸承蓋reliefvalve

安全閥，溢流閥staybolt

貫穿螺栓，拉桿螺栓NewWordsandExpressionsstuffingbox

填料函cylinderliner

氣缸套scavengeairreceiver

掃氣箱coolingjacket

冷卻水套indicatorcock

示功閥Theconstructionofmarinedieselengineiscomplex.Althoughthestructuresandmodelsofvariousdieselenginesaredifferent,thedieselengineismainlycomposedofthesamecomponentsandsystemsintermsofworkingprincipleandoverallstructure.(盡管柴油機的結(jié)構(gòu)、型號各異，但從工作原理和總體結(jié)構(gòu)上看柴油機基本都由相同的部件和系統(tǒng)組成)Themaincomponentsofdieselenginecanbedividedintofixedpartsandmovingparts(alsoknownasrunninggear).Thefixedpartsmainlyincludebedplate,frame,cylinderandcylindercover,whilethemovingpartsarepiston,crosshead(onlyintwo-strokeengine),connectingrodandcrankshaft(seeFig.3-1).Thesecomponentsconstitutethemainbodyofthedieselengine,theirworknotonlydirectlyaffectsthetechnicalperformanceofthedieselengine,butalsocloselyrelatedtothesafetyofnavigation.3.1TheBedplateThebedplate(seeFig.3-2),whichinmostcasesisoftheweldeddesign,isboltedtotheseatingwhichformsapartofthedoublebottomoftheship.Itissecuredinthetransversedirectionbymeansofboltsknownasside-chockboltsandinlongitudinaldirectionbymeansofend-chockbolts(機座大多數(shù)情況是焊接式的，它與底座組成船舶雙層底的一部分。機座通過稱為側(cè)楔墊螺栓的螺栓橫向固定，通過端楔墊螺栓縱向固定。).3.1TheBedplateThebedplateisthefoundationonwhichthetwo-strokeengineisbuilt.Itmustberigidenoughtosupporttheweightoftherestoftheengine.Thebedplateismadeinoneormoresections,dependingonthenumberofcylinders.Iftherearetwoormoresections,thesearejoinedtogetherwithfittedbolts.Thebedplateconsistsoftwowelded,longitudinalgirderswhichrunthelengthoftheengineandanumberofcrossgirderswhichsupportthemainbearings.Themainbearingsconsistoftwoshells,linedwithbearingmetal,whicharesupportedinhousingsmachinedinthebedplate.Eachmainbearinghasoneortwomainbearingcapswhicharesecuredbystudsandnuts,designedfortighteningwithhydraulictools.3.2TheFrameAframe(alsoknownasA-frameorcolumn)isboltedontothetopofthebedplate,showninFig.3-3.Likethebedplate,theframeconsistsofoneormoresections.Together,thebedplateandtheframeconstitutethecrankcaseoftheengine.3.2TheFrameTheframeisfittedwithsteelplatedoorsforaccesstothecrossheadsandtothemainandcrankpinbearings.Ontheexhaustsideoftheengineanumberofspringloadedreliefvalvesarefitted,whichwillopenintheeventofexcessivepressureinthecrankcase/chaincasing,forinstanceasaresultoftheignitionofoilmist.3.3TheCylinder3.3TheCylinderThecylinderframe(seeFig.3-4)isdesignedwithanintegratedcamshafthousing.Thecylindersectionistightenedtogetherwiththeengineframeandthebedplatebymeansofstayboltstoachieveagreaterrigidconstructionwithlessdeformationinserviceandlowervibration(氣缸部分與機器的機架和機座通過貫穿螺栓緊固在一起，形成一個更堅固的結(jié)構(gòu)，在使用中變形更小，振動更低).CylinderFrame3.3TheCylinderAlternativelyasacompleteweldedassemblyintegratingthescavengeairreceiverintothecylinderframe.Centralboresatthetopofthecylinderframeenclosethecylinderliners.Centralboresinthebottomofthecylinderframeenclosethepistonrodstuffingboxes.Ontheexhaustsideofthecylinderframethereareopeningswhichconnectthescavengeairspacearoundthecylinderlinerwiththelongitudinalscavengeairreceiveroftheengine.Therearealsoinletpipesforcoolingandlubricatingoil.Thecylinderframeisprovidedwithcleaningandinspectioncoversgivingaccesstothescavengeairspaces.CylinderFrame3.3TheCylinderThecylinderliner(seeFig.3-4)ismadeofalloyedcastironandthecylindersurfaceissometimeschromium-plated.Formanyhighlyratedtwo-strokeengines,thecylinderframedoesnotalwayshousethewaterjacketwhichisinsteadprovidedbymeansofaseparateunitmountedabovetheframe.Suchanarrangementprovidescoolingjustwhereitisrequired,attheupperpartofthecylinderlinerandalsoavoidstheriskofcoolingwaterleakingintothecrankcaseorofoilfromthecrankcasegainingentrytothecoolingwatersystem(這種布置僅對所需部位提供冷卻，即氣缸套上部，并避免了冷卻水泄漏到曲軸箱或滑油從曲軸箱進入冷卻水系統(tǒng)的風險).CylinderLiner3.3TheCylinderThelinerislocatedwithinthisjacketunitandsealingringsareprovidedtopreventwaterleakage.Thecylinderlineristightenedagainstthetopofthecylinderframebythetensioningforcefromthecylindercoverstudsbeingtransmittedviathecylindercover.Thepartofthecylinderlinerwhichislocatedinthescavengeairspaceofthecylinderframeisprovidedwithanumberofscavengeairports,whichareuncoveredbythepistonwhenthisisinitsbottomposition.Thescavengeairportsareboredatanobliqueangletotheaxisofthecylinderlinersoastogivethescavengeairarotarymovementinthecylinder.CylinderLiner3.3TheCylinderInthefreepartofthecylinderliner,betweenthecoolingjacketandthecylinderframe,thereareanumberofboreswithnon-returnvalvesforthesupplyoflubricatingoiltothecylinder.Thelubricatingoilflowsoutoftheseboresathighpressure.ThelubricatinggroovesgiveequallubricationontothecylinderlinerwallOnsometypeofengines,apistoncleaning(PC)ringismountedatthetopofthecylinderliner.ThepurposeofthePCringistopreventthebuildingupofdepositsonthepistontoplandand,inturn,preventthewipingawayofthecylinderlubricatingoil(清潔環(huán)的作用是防止在活塞頂部形成沉積物，進而防止氣缸潤滑油被擦掉).Consequently,thePCringcontributestoreducingthewearoflinersandrings.CylinderLiner3.3TheCylinderEachcylinderisclosedatthetopbyacylindercover(alsoknownascylinderhead),madeofspecialheat-resistantsteel,showninFig.3-5.Ineachcylindercoverisalargecentralopeningformountingtheexhaustvalvewhichisattachedbymeansoffourstudsandnuts,andtwoorthreeholesforthefuelvalves.Thecylindercoverisalsoprovidedwithholesforanumberofotherfittingssuchasairstartvalve,reliefvalveandindicatorcock.TheCylinderCover3.3TheCylinderAswithcylinderliners,coolingcanpresentproblemsrelatedtothermalstressandaneffectivesystemofcoolantcirculationisneeded.Acoolingjacketismountedonthelowerpartofthecylindercover,wherebyacoolingwaterspaceisformed.Anothercoolingwaterspaceisformedaroundtheexhaustvalveseat,whentheexhaustvalveisinstalled.Thesetwospacescommunicatethroughalargenumberofcoolingboresinthecover.Thewaterissuppliedfromthecoolingjacketsurroundingthecylinderlinerandpassesthroughwaterconnectionstothecoolingjacketsurroundingthecylindercoverand,furtheron,throughthecoolingbores,tothespacearoundtheexhaustvalveseat(水從氣缸套周圍的冷卻水套被供入，并通過冷卻水接頭到氣缸蓋周圍的冷卻水套，然后通過冷卻孔，到達排氣閥座周圍的空間).TheCylinderCover3.3TheCylinderFromherethewaterisdischargedtothemaincoolingwateroutletpipe.Onsomeenginetypes,anamountofwaterisalsopasseddirectlyfromthecylindercovertotheexhaustvalvehousingthroughacoolingwaterconnection.Thecylindercoveristightenedagainstthetopofthecylinderlinerwithnutsandlongstudsfittedinthecylinderframe.Thenutsaretightenedwithhydraulictools.Sealingbetweenthecylindercoverandcylinderlinerisobtainedbymeansofasealingringofmildsteel.TheCylinderCover

Exercises1.Thelinerislocatedwithinthisjacketunitand________areprovidedtopreventwaterleakage.A.scraperrings B.stuffC.compressionrings D.sealingrings2._____aremountedonandboltedtothebedplatecrossgirders.A.Thecrankshafts B.ThecrankcasesC.Thecylinders D.TheframesDD

Exercises3.Thebearingsusedtosupportthecrankshaftofadieselenginearegenerallycalled__________.A.lineshaftbearings B.connectingrodbearingsC.mainbearings D.supportbearings4.Thepistonhaspassedthetop