Unit 2汽车专业英语(发动机)

Unit2-1

MainComponentsofEngine

ContentsⅠ．Pre-questionsII.Text

ExplanationIII.ExercisesPre-questionsTheheartofautomobileWhatimpressionoftheengine?complicatedpowerPre-questionsWhatarethetypesoftheengine?electricmotors,steamengines,andinternalcombustionenginesWhat’stheinternalcombustionengine?

burnsfuelwithinthecylindersandconvertstheexpandingforceofthecombustionintorotaryforceusedtopropelthevehicle.Pre-questionsWords&phrasesIntakemanifold[‘mænɪfəʊld]进气管throttle

[‘θrɒt(ə)l]valve[vælv]节气门Cylinder[‘sɪlɪndə]headcover气缸盖罩Distributor

[dɪ‘strɪbjʊtə]分电器Cylindercover气缸盖Vent-pipe

[‘ventpaip]排气管Cylinderblock气缸体Sparkplug

[plʌg]火花塞timingdrivingroomcover正时传动室盖Timingbelt正时齿轮带Words&phrasesCamshaft

[‘kæmʃɑːft]凸轮轴Campulley[‘pʊlɪ]凸轮带轮Crankshaft

[‘kræŋkʃɑːft]曲轴Crankshafttimingbeltgearwheel曲轴正时齿形带轮Flywheel飞轮Waterjacket水套Piston['pɪst(ə)n]活塞Sump[sʌmp]油底壳Mechanism

[‘mek(ə)nɪz(ə)m]机械装置，原理Connectingrod连杆lubricating

[‘lu:brikeitiŋ]

system润滑系统Single-cylinderenginecylinderpistonPistonpinConnectingrodcrankshaftOilpipeIntakevalveExhaustvalveTiminggearOilpumpwhatisthepowersourceofautomobileandhowtoproduce?pistonpistonpinconnectingrodcrankshaftEnginePowerisproducedbythelinearmotionofapistoninacylinder.

Theconnectingrodtransmitstheup-and-downmotionofthepistontothecrankshaft,whichchangesitintorotarymotion.

Pre-questionsTheenginecomprisestwomechanismandfivesystems,whatarethey?crankshaftandconnectingrodmechanism（曲轴连杆装置）,valvegear(阀动装置）,coolingsystem,lubricatingsystem,fuelsystem,startingsystem,ignitionsystemPre-questions9connectingrodflywheelcrankshaftpistonintakevalveexhaustvalvepushrodtappettiminggears■

Valvegear

■

Connectingrod

EnginecoolingsystemEnginelubricatingsystemFuelsupplysystemValvegearpistoncrankshaftdistributorsumptiminggearcrankshaftandconnectingrodmechanismvalvegearfuelsystemSparkplugexhaustmanifoldIII.ExercisesTranslatethefollowingexpressionsintoChinese.活塞曲轴分电器油底壳正时齿轮曲柄连杆机构配气机构燃油系统火花塞排气歧管1-cylinderheadcover2-piston3-timingbelt4-waterpump5-sump6-oilpump7-crankshaft8-flywheel9-distributor10-valveIII.ExercisesReadingHowanEngineWorksTheinternalcombustionengine,asitsnameindicates,burnsfuelwithinthecylindersandconvertsexpandingforceofthecombustionintorotaryforceusedtopropelthevehicle.Theactionstakingplaceintheenginecylindercanbeclassifiedintofourstages,orstroke.“stroke”referstopistonmovement;pel[prə‘pel]v.推动，驱动limitingposition极限位置Theinternalcombustionengine,asitsnameindicates,burns

fuelwithinthecylindersandconvertstheexpandingforceofthecombustionintorotaryforceusedtopropelthevehicle.译文：内燃机，顾名思义，就是燃料在气缸内部燃烧，并且把燃烧时的膨胀力转化为驱动车辆的旋转力。II.TextExplanationConvert…..into….①转变；变换Thatbuildinghasbeenconvertedintoaschool.那座楼房改成学校了。②兑换IwanttoconvertsomeHongKongdollarsintoAmericandollars.我想把一些港元换成美元。③改变信仰、党派或意见等Shemanagedtoconverthimtoheropinion.她终于设法说服了他接受她的意见。II.TextExplanationReadingHowanEngineWorks.Theactionstakingplaceintheenginecylindercanbeclassifiedintofourstages,orstroke.发动机气缸内的工作过程可以分为四个过程或冲程。beclassifiedinto….①分类为、被分成Memorycan

beclassifiedinto

short-termandlong-termmemory.记忆可分为长期记忆和短期记忆。II.TextExplanationReadingHowanEngineWorks“Stroke”referstopistonmovement;astrokeoccurswhenthepistonmovesfromonelimitingpositiontotheother.“冲程”指的是活塞的运动。当活塞从一个极限位置移动到另一个极限位置，即完成了一次冲程。ReadingTheupperlimitofpistonmovementiscalledTDC(topdeadcenter).ThelowerlimitofpistonmovementiscalledBDC(bottomdeadcenter).AstrokeispistonmovementfromTDCtoBDCorfromBDCtoTDC.活塞运动的上极限位置被称为TDC（上止点）。活塞的下极限位置被称为BDC（下止点）。一个冲程是指活塞从上止点运动到下止点或者从下止点运动到上止点。ReadingInotherwords,thepistoncompletesastrokeeachtimeitchangesitsdirectionofmotion.换句话说，活塞每完成一次冲程就会改变运动方向。Inotherwords

Inotherwords,theyremainrelativelyconstantorstatic.

换句话说，它们相对的稳定、静止。

Inotherwords,wehaveadheredtoscientificsocialism.

也就是说，我们坚持了科学社会主义ReadingWheretheentirecycleofeventsinthecylinderrequiresfourstrokes(ortwocrankshaft

revolutions),theengineiscalledafour-stroke-cycleengine.Thefourpistonstrokesareintake,compression,powerandexhaust.气缸内的全部循环运动需要四冲程（或称为二次曲轴转动），这种发动机称为四冲程循环发动机。活塞的四冲程分别为进气行程、压缩行程、做功行程和排气行程。ReadingIntakestroke.Ontheintakestroke,theintakevalvehasopened,thepistonismovingdownward,andamixtureofairandvaporizedgasolineisenteringthecylinderthroughthevalveport.Themixtureofairandvaporizedgasolineisdeliveredtothecylinderbythefuelsystemandcarburetor.Vaporized[‘veɪpəraɪzd]adj.汽化的carburetor[,kɑːbjʊ‘retə]n.汽化器ReadingOntheintakestroke,theintakevalvehasopened,thepistonismovingdownward,andamixtureofairandvaporizedgasolineisenteringthecylinderthroughthevalveport.“在进气行程中，进气门打开，活塞向下移动，可燃混合气通过进气门进入气缸。ReadingThemixtureofairandvaporizedgasolineisdeliveredtothecylinderbythefuelsystemandcarburetor.适当浓度的可燃混合气是由燃料系统和化油器提供的。Compressionstroke.AfterthepistonreachesBDC,orthelowerlimitofitstravel.Itbeginstomoveupwards.Asthishappens,theintakevalvecloses.Theexhaustvalveisalsoclosed,sothatthecylinderissealed.Asthepistonmovesupward(pushednowbytherevolvingcrankshaftandconnectingrod),theair-fuelmixtureiscompressedtoaslittleasone-tenthofitsoriginalvolume,orevenless.Whentheair-fuelmixtureiscompressed,notonlydoesthepressureinthecylindertoup,butthetemperatureofthemixturealsoincreases.revolving[rɪ‘vɒlvɪŋ]adj.旋转的volume

[‘vɒljuːm]n.量AfterthepistonreachesBDC,orthelowerlimitofitstravel.Itbeginstomoveupwards.Asthishappens,theintakevalvecloses.Theexhaustvalveisalsoclosed,sothatthecylinderissealed.在活塞到达下止点时或者是活塞下限时，活塞开始向上运动。同时，进气门关闭，排气门也关闭，所以这时的汽缸是封闭的。Asthepistonmovesupward(pushednowbytherevolvingcrankshaftandconnectingrod),theair-fuelmixtureiscompressedtoaslittleasone-tenthofitsoriginalvolume,orevenless.当活塞向上运动时(这时是由转动的曲轴和连杆推动活塞)，可燃混合气被压缩。当活塞到达上止点时，可燃混合气被压缩到有原体积的十分之下甚至更少。Whentheair-fuelmixtureiscompressed,notonlydoesthepressureinthecylindertoup,butthetemperatureofthemixturealsoincreases.当油气混合燃料被压缩时，不仅汽缸里的压力上升，可燃混合气的温度也随之增加了。Powerstroke.AsthepistonreachesTDConthecompressionstroke,andelectricsparkisproducedatthesparkplug.Theignitionsystemdeliversahigh-voltagesurgeofelectricitytothesparkplugtoproducethespark.Thesparkignitestheair-fuelmixture.Itnowbeginstoburnveryrapidly,andthecylinderpressureincreasedtoasmuchas3-5MPaorevenmore.Thisterrificpushagainstthepistonforcesitdownward,andapowerimpulseistransmittedthroughtheconnectingrodtothecrankpinonthecrankshaft.Thecrankshaftisrotatedasthepistonispusheddownbythepressureaboveit.AsthepistonreachesTDConthecompressionstroke,andelectricsparkisproducedatthesparkplug.Theignitionsystemdeliversahigh-voltagesurgeofelectricitytothesparkplugtoproducethespark.当活塞到达压缩行程的上止点时，火花塞产生电火花。电火花是由点火系统向火花塞提供高压电脉冲而产生的。

Thesparkignitestheair-fuelmixture.Itnowbeginstoburnveryrapidly,andthecylinderpressureincreasedtoasmuchas3-5MPaorevenmore.

电火花点燃可燃混合气。可燃混合气开始发生剧烈燃烧，气缸内压力达到3-5兆帕，甚至更高。Thisterrificpushagainstthepistonforcesitdownward,andapowerimpulseistransmittedthroughtheconnectingrodtothecrankpinonthecrankshaft.Thecrankshaftisrotatedasthepistonispusheddownbythepressureaboveit.作用于活塞上强大的推动力推动活塞向下运动，并将这一推力通过连杆传到曲轴上的连杆轴颈上。因此，当活塞受压向下运动时，推动曲轴转动。Exhauststroke.AsthepistonreachesBDCagain,theexhaustvalveopens.Now,asthepistonmovesupontheexhauststroke,itforcestheburnedgasesoutofthecylinderthroughtheexhaust-valveport.Then,whenthepistonreachesTDC,theexhaustvalveclosedandtheintakevalveopens.Now,afreshchargeofair-fuelmixturewillbedrawnintothecylinderasthepistonmovesdowntowardBDC.Thisfourstrokecycleofpistonwithinthecylinderisrepeatedtimeandagaintoputthevehicleforward.AsthepistonreachesBDCagain,theexhaustvalveopens.Now,asthepistonmovesupontheexhauststroke,itforcestheburnedgasesoutofthecylinderthroughtheexhaust-valveport.当活塞再一次到达下止点时，排气门打开。同时，活塞向上移动，把废气经排气门排出气缸。Then,whenthepistonreachesTDC,theexhaustvalveclosedandtheintakevalveopens.Now,afreshchargeofair-fuelmixturewillbedrawnintothecylinderasthepistonmovesdowntowardBDC.随后活塞达到上止点，排气门关闭，进气门打开。当活塞又一次向下移动到达下止点时，新鲜燃混合气被吸入气缸。Thisfourstrokecycleofpistonwithinthecylinderisrepeatedagainandagaintoputthevehicleforward.上述的四个行程又继续重复，推进车辆前进。strokeBDCTDCsurgeterrificcrankpinintakestrokeCompressionstrokepowerstrokeexhauststrokefreshcharge行程，冲程；上止点；下止点；冲击，脉动；了不起的，绝妙的；曲柄销，连杆轴颈；吸气冲程；压缩冲程；做功冲程；排气冲程；吸入的新鲜混合油气I.TranslatethefollowingsentencesintoChinese.1．Engineisthepowersourceoftheautomobile.Powerisproducedbythelinearmotionofapistoninacylinder.发动机是汽车的