轮机英语课件

MarineEngineeringEnglish《轮机英语》APracticalCourseforEngineersWorkingonBoardShips

Lesson2

TheWorkingPrincipleofMarineDiesel

2LearningObjectives:1.Graspsomeusefulwordsandexpressionsinthewholetext.2.Afterstudyingthelesson,heorshewillhaveabetterunderstandingofTheWorkingPrincipleofMarineDiesel3

4part1

NewWordsandExpressions5ignite v.点燃inject v.喷射principle n.原理，原则adjacent a.相邻的fine a.细小的，好的rotate v.旋转，回转event n.事件，过程stroke n.冲程，行程inlet n.进口，入口theoretically ad.理论上地inefficient a.效率低的，无效的advantage n.优势，优点，效益application n.应用propulsion n.推进(装置)cause n.原因；v.引起expand v.膨胀expansion n.膨胀sequence n.顺序，系列inturn 依次，轮流bottomdeadcenter 下止点，下死点topdeadcenter 上止点，上死点onboardship 在船上reductiongearbox 减速齿轮箱Lesson2TheWorkingPrincipleofMarineDieselNewWordsandExpressions6part2

TextAnalysisExhaustvalveInletvalveFuelinjectorCylinderPistonPistonringConnectingrodFour-strokedieselengineCombustionchamberPistonpincrankshaftCrankwebFuelinjectorFuelinjectorExhaustvalve扫气口ScavengeportExhaust

portTwo-strokeEngineCrossscavengesystemUniflowscavengesystemPistonrodConnecting

rodPistonpinCrossheadThedieselengineisatypeofinternalcombustionenginewhichignites(点燃)thefuelbyinjecting(喷射)itintohot,highpressureairinacombustionchamber(燃烧室).Lesson2TheWorkingPrincipleofMarineDiesel柴油Text9内燃机柴油机是内燃机的一种类型，通过将燃油喷射进行入热的、高压的空气中，来点燃燃油，在燃烧室内。Themarinedieselengineisatypeofdieselengineusedonships.Theprincipleofitsoperationisasfollows:Lesson2TheWorkingPrincipleofMarineDiesel船用的Text10原理船用柴油机就是用在船上的柴油机，操作原理如下：Achargeoffreshairisdrawn（吸入）orpumpedintotheenginecylinder(气缸)andthencompressed（压缩）bythemovingpiston(活塞)toveryhighpressure.Lesson2TheWorkingPrincipleofMarineDiesel填充，进入Text11新鲜空气泵一定量的新鲜空气，被吸入或者泵入发动机气缸，然后被移动的活塞压缩到非常高的压力。12Whentheairiscompressed,itstemperaturerisessothatitignites（点燃，着火）thefinespray(喷雾、油雾)offuelinjectedintothecylinder（汽缸）.Lesson2TheWorkingPrincipleofMarineDiesel压缩Text13温度喷射当空气被压缩，空气的温度会上升，高温会点燃燃油喷雾Theburningofthefueladdsmoreheattotheaircharge,causingittoexpand（膨胀）andforcetheenginepistontodoworkonthecrankshaft（曲轴）whichinturndrivestheship’spropeller(螺旋桨).Lesson2TheWorkingPrincipleofMarineDiesel填充空气Text14密度增压燃油的燃烧增加了更多的热量给进气空气，引起空气膨胀，迫使活塞对曲轴做功，曲轴接下来驱动螺旋桨。ExhaustvalveInletvalveFuelinjectorCylinderPistonPistonringConnectingrodFour-strokedieselengineCombustionchamberPistonpincrankshaftCrankwebFuelinjectorFuelinjectorExhaustvalve扫气口ScavengeportExhaust

portTwo-strokeEngineCrossscavengesystemUniflowscavengesystemPistonrodConnecting

rodPistonpinCrossheadTheoperationbetweentwofuelinjectionsiscalledaworkingcycle,whichconsistsofafixedsequenceofevents.Thiscyclemaybeachieved（达到，完成）eitherinfourstrokes(冲程、行程)ortwo.Lesson2TheWorkingPrincipleofMarineDiesel喷射Text17包含事件两次燃油喷射直接的操作叫做一个循环，循环包括固定顺序的事件.

Inafour-strokedieselengine,thecyclerequiresfourseparatestrokesofthepiston,i.e.suction(吸气),compression(压缩),expansion(膨胀)andexhaust(排气).Lesson2TheWorkingPrincipleofMarineDieselText18冲程活塞四冲程柴油机中，每个循环需要活塞的四个冲程：Ifwecombinethesuctionandexhaustoperationswiththecompressionandexpansionstrokes,thefour-strokeenginewillbeturnedintoatwo-strokeone,asisshowninFigures1-a)—d).Lesson2TheWorkingPrincipleofMarineDiesel结合Text19把吸气、排气两个冲程合并到压缩和膨胀这两个冲程中，四冲程就变成了二冲程。Scavenge(a)Compression(b)Injection(c)Exhaust(d)ScavengeportExhaustportFuelinjectorCylinderPistonConnectingrodCrankThetwo-strokecyclebeginswiththepistoncomingupfromthebottomofitsstroke,i.e.bottomdeadcenter(BDC),withtheairinletportsorscavengeports(扫气口)inthesidesofthecylinderbeingopened(Fig.1-a)).Lesson2TheWorkingPrincipleofMarineDieselText21底部下止点二冲程循环开始于活塞在下止点，此时，位于一侧的扫气口是开启的Theexhaustportsareuncoveredalso.Pressurizedfreshairchargesintothecylinder,blowingoutanyresidualexhaustgasesfromthelaststrokethroughtheexhaustports.Lesson2TheWorkingPrincipleofMarineDiesel开启的Text22有压力的残余的排气口也是打开的，有压力的新鲜空气进入气缸，吹除来自于上一个冲程的残余的废气。Asthepistonmovesaboutonefifthofthewayup,itclosestheinletportsandtheexhaustports.Theairisthencompressedasthepistonmovesup.(Fig.1-b)).Lesson2TheWorkingPrincipleofMarineDiesel五分之一Text23当活塞上行到五分之一，它就关闭了进气口和排气口，空气接下来被上行的活塞压缩。Whenthepistonreachesthetopofitsstroke,i.e.thetopdeadcenter(TDC),boththepressureandthetemperatureoftheairrisetoveryhighvalues.Lesson2TheWorkingPrincipleofMarineDieselText24上止点当活塞到达上止点的时候，压力和温度都达到很高的值Thefuelinjectorinjectsafinesprayoffuelintothehotairandcombustiontakesplace,producingmuchhigherpressureinthegases.Lesson2TheWorkingPrincipleofMarineDieselText25喷油器良好的喷雾喷油器喷入燃油的喷雾，到热的空气中，燃烧就开始了，产生更高的压力Thepistonisforced(迫使)downwardasthehighpressuregasesexpanduntilituncoverstheexhaustports.Lesson2TheWorkingPrincipleofMarineDieselText26打开了活塞被迫使向下运动，直到活塞打开了排气口Theburninggasesbegintoexhaust(Fig.1-d))andthepistoncontinuesdownuntilitopenstheinletports.Thenanothercyclebegins.Lesson2TheWorkingPrincipleofMarineDieselText27进气口燃烧的燃气开始排出，活塞继续下行，直到打开进气口，另外一个循环开始了28Inthetwo-strokeengine,eachrevolutionofthecrankshaft(曲轴)makesonepowerorworkingstroke,whileinthefour-strokeengine,ittakestworevolutionstomakeonepowerstroke.Lesson2TheWorkingPrincipleofMarineDieselText29转（名词）二冲程发动机，曲轴每转产生一个做功冲程。。Thatiswhyatwo-strokecycleenginewilltheoretically（理论上）developtwice(twotimes)thepowerofafour-strokeengineofthesamesize.Lesson2TheWorkingPrincipleofMarineDieselText30功率这就是为什么，二冲程柴油机理论上是同尺寸四冲程发动机功率的两倍Inefficientscavenging（换气不充分）andotherlosses,however,reducethepoweradvantagetoabout1.8.Lesson2TheWorkingPrincipleofMarineDieselText31优势因为换气不充分等原因，实际功率优势大概是1.8Eachtypeofenginehasitsapplicationonboardship.Theslowspeed(i.e.90to120rev/min)mainpropulsiondieseloperatesonthetwo-strokecycle.Lesson2TheWorkingPrincipleofMarineDiesel应用Text32主推进柴油机每种类型的柴油机都有自己的应用。Atthislowspeedtheenginerequiresnoreductiongearboxbetweenitandpropeller.Lesson2TheWorkingPrincipleofMarineDieselText33减速齿轮箱螺旋桨低速机不需要减速箱Thefour-strokeengine(usuallyrotatingatmediumspeed,between250to750rev/min)isusedforalternatorsandsometimesformainpropulsionwithagearboxtoprovideapropellerspeedofbetween90to120rev/min.Lesson2TheWorkingPrincipleofMarineDieselText34中等速度发电机四冲程发动机运行于中等速度，约250-750转/分钟。通常用来驱动发电机，有时候也作为主机，但是需要齿轮箱。35part3

Exercise&Examination1.Inthetwo-strokeengine,eachrevolutionof_____makesonepowerorworkingstroke. A.theturninggear

B.theturbo-charger C.thecrankshaft

D.thecompressorLesson1DifferentTypesofMarinePropulsionPlant做工冲程Exercise36盘车机二冲程柴油机中,曲轴每转一转,就产生一个作功冲程。曲轴2.Thefour-strokecycleissocalledbecauseittakes_____tocompletetheprocessesneededtoconverttheenergyinthefuelintowork. A.twostrokesofthepiston B.fourstrokesofthepiston C.onerevolutionofthecamshaft D.fourrevolutionsofthecrankshaftLesson1DifferentTypesofMarinePropulsionPlantExercise37之所以被称为四冲程机是因为其需要四个冲程来完成将燃油能量转变为功的过程。3.Thecompressionratioofadieselenginereferstotheratiobetweenthe_____. A.pistonareatoconnectingrodlength B.cylindervolumesatbottomdeadcenterandattopdeadcenter C.enginecylindersizetopistonsize D.thenumberofcompressionstrokesforagivenhorsepowerLesson1DifferentTypesofMarinePropulsionPlant压缩比Exercise38柴油机的压缩比是指下死点时气缸的容积与上死点时气缸的容积之比。4.Theslow-speeddieselenginerotatesatthislowspeedandthecrankshaftisthus_____tothepropellershafting. A.indirectlycoupled B.driven C.geared D.directlycoupledLesson1DifferentTypesofMarinePropulsionPlant螺旋桨Exercise39低速柴油机在此低转速范围内转动,因此其曲轴可以和螺旋桨轴直接相连。 5.The_____isthepoweravailableattheoutputshaftoftheengineandcanbemeasuredusingatorsionmeterorwithabrake. A.electricpower B.shaftpower C.indicatedpower D.mechanicalpowerLesson1DifferentTypesofMarinePropulsionPlantExercise40轴功率轴功率是发动机轴上可以获得的功率,可以使用转矩表或刹车来测量。1.Propulsionofthevastmajorityofcontemporarymerchantship(