Unit2-1

MainComponentsofEngine

ContentsⅠ．Pre-questionsII.Text

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

burnsfuelwithinthecylindersandconvertstheexpandingforceofthecombustionintorotaryforceusedtopropelthevehicle.Pre-questionsWords&phrasesIntakemanifold[‘m?n?f??ld]進氣管throttle

[‘θr?t(?)l]valve[v?lv]節(jié)氣門Cylinder[‘s?l?nd?]headcover氣缸蓋罩Distributor

[d?‘str?bj?t?]分電器Cylindercover氣缸蓋Vent-pipe

[‘ventpaip]排氣管Cylinderblock氣缸體Sparkplug

[pl?g]火花塞timingdrivingroomcover正時傳動室蓋Timingbelt正時齒輪帶Words&phrasesCamshaft

[‘k?m?ɑ?ft]凸輪軸Campulley[‘p?l?]凸輪帶輪Crankshaft

[‘kr??k?ɑ?ft]曲軸Crankshafttimingbeltgearwheel曲軸正時齒形帶輪Flywheel飛輪Waterjacket水套Piston['p?st(?)n]活塞Sump[s?mp]油底殼Mechanism

[‘mek(?)n?z(?)m]機械裝置，原理Connectingrod連桿lubricating

[‘lu:brikeiti?]

system潤滑系統Single-cylinderenginecylinderpistonPistonpinConnectingrodcrankshaftOilpipeIntakevalveExhaustvalveTiminggearOilpumpwhatisthepowersourceofautomobileandhowtoproduce?pistonpistonpinconnectingrodcrankshaftEnginePowerisproducedbythelinearmotionofapistoninacylinder.

Theconnectingrodtransmitstheup-and-downmotionofthepistontothecrankshaft,whichchangesitintorotarymotion.

Pre-questionsTheenginecomprisestwomechanismandfivesystems,whatarethey?crankshaftandconnectingrodmechanism（曲軸連桿裝置）,valvegear(閥動裝置）,coolingsystem,lubricatingsystem,fuelsystem,startingsystem,ignitionsystemPre-questions9connectingrodflywheelcrankshaftpistonintakevalveexhaustvalvepushrodtappettiminggears■

Valvegear

■

Connectingrod

EnginecoolingsystemEnginelubricatingsystemFuelsupplysystemValvegearpistoncrankshaftdistributorsumptiminggearcrankshaftandconnectingrodmechanismvalvegearfuelsystemSparkplugexhaustmanifoldIII.ExercisesTranslatethefollowingexpressionsintoChinese.活塞曲軸分電器油底殼正時齒輪曲柄連桿機構配氣機構燃油系統火花塞排氣歧管1-cylinderheadcover2-piston3-timingbelt4-waterpump5-sump6-oilpump7-crankshaft8-flywheel9-distributor10-valveIII.ExercisesReadingHowanEngineWorksTheinternalcombustionengine,asitsnameindicates,burnsfuelwithinthecylindersandconvertsexpandingforceofthecombustionintorotaryforceusedtopropelthevehicle.Theactionstakingplaceintheenginecylindercanbeclassifiedintofourstages,orstroke.“stroke”referstopistonmovement;pel[pr?‘pel]v.推動，驅動limitingposition極限位置Theinternalcombustionengine,asitsnameindicates,burns

fuelwithinthecylindersandconvertstheexpandingforceofthecombustionintorotaryforceusedtopropelthevehicle.譯文：內燃機，顧名思義，就是燃料在氣缸內部燃燒，并且把燃燒時的膨脹力轉化為驅動車輛的旋轉力。II.TextExplanationConvert…..into….①轉變；變換Thatbuildinghasbeenconvertedintoaschool.那座樓房改成學校了。②兌換IwanttoconvertsomeHongKongdollarsintoAmericandollars.我想把一些港元換成美元。③改變信仰、黨派或意見等Shemanagedtoconverthimtoheropinion.她終于設法說服了他接受她的意見。II.TextExplanationReadingHowanEngineWorks.Theactionstakingplaceintheenginecylindercanbeclassifiedintofourstages,orstroke.發(fā)動機氣缸內的工作過程可以分為四個過程或沖程。beclassifiedinto….①分類為、被分成Memorycan

beclassifiedinto

short-termandlong-termmemory.記憶可分為長期記憶和短期記憶。II.TextExplanationReadingHowanEngineWorks“Stroke”referstopistonmovement;astrokeoccurswhenthepistonmovesfromonelimitingpositiontotheother.“沖程”指的是活塞的運動。當活塞從一個極限位置移動到另一個極限位置，即完成了一次沖程。ReadingTheupperlimitofpistonmovementiscalledTDC(topdeadcenter).ThelowerlimitofpistonmovementiscalledBDC(bottomdeadcenter).AstrokeispistonmovementfromTDCtoBDCorfromBDCtoTDC.活塞運動的上極限位置被稱為TDC（上止點）?；钊南聵O限位置被稱為BDC（下止點）。一個沖程是指活塞從上止點運動到下止點或者從下止點運動到上止點。ReadingInotherwords,thepistoncompletesastrokeeachtimeitchangesitsdirectionofmotion.換句話說，活塞每完成一次沖程就會改變運動方向。Inotherwords

Inotherwords,theyremainrelativelyconstantorstatic.

換句話說，它們相對的穩(wěn)定、靜止。

Inotherwords,wehaveadheredtoscientificsocialism.

也就是說，我們堅持了科學社會主義ReadingWheretheentirecycleofeventsinthecylinderrequiresfourstrokes(ortwocrankshaft

revolutions),theengineiscalledafour-stroke-cycleengine.Thefourpistonstrokesareintake,compression,powerandexhaust.氣缸內的全部循環(huán)運動需要四沖程（或稱為二次曲軸轉動），這種發(fā)動機稱為四沖程循環(huán)發(fā)動機。活塞的四沖程分別為進氣行程、壓縮行程、做功行程和排氣行程。ReadingIntakestroke.Ontheintakestroke,theintakevalvehasopened,thepistonismovingdownward,andamixtureofairandvaporizedgasolineisenteringthecylinderthroughthevalveport.Themixtureofairandvaporizedgasolineisdeliveredtothecylinderbythefuelsystemandcarburetor.Vaporized[‘ve?p?ra?zd]adj.汽化的carburetor[,kɑ?bj?‘ret?]n.汽化器ReadingOntheintakestroke,theintakevalvehasopened,thepistonismovingdownward,andamixtureofairandvaporizedgasolineisenteringthecylinderthroughthevalveport.“在進氣行程中，進氣門打開，活塞向下移動，可燃混合氣通過進氣門進入氣缸。ReadingThemixtureofairandvaporizedgasolineisdeliveredtothecylinderbythefuelsystemandcarburetor.適當濃度的可燃混合氣是由燃料系統和化油器提供的。Compressionstroke.AfterthepistonreachesBDC,orthelowerlimitofitstravel.Itbeginstomoveupwards.Asthishappens,theintakevalvecloses.Theexhaustvalveisalsoclosed,sothatthecylinderissealed.Asthepistonmovesupward(pushednowbytherevolvingcrankshaftandconnectingrod),theair-fuelmixtureiscompressedtoaslittleasone-tenthofitsoriginalvolume,orevenless.Whentheair-fuelmixtureiscompressed,notonlydoesthepressureinthecylindertoup,butthetemperatureofthemixturealsoincreases.revolving[r?‘v?lv??]adj.旋轉的volume

[‘v?lju?m]n.量AfterthepistonreachesBDC,orthelowerlimitofitstravel.Itbeginstomoveupwards.Asthishappens,theintakevalvecloses.Theexhaustvalveisalsoclosed,sothatthecylinderissealed.在活塞到達下止點時或者是活塞下限時，活塞開始向上運動。同時，進氣門關閉，排氣門也關閉，所以這時的汽缸是封閉的。Asthepistonmovesupward(pushednowbytherevolvingcrankshaftandconnectingrod),theair-fuelmixtureiscompressedtoaslittleasone-tenthofitsoriginalvolume,orevenless.當活塞向上運動時(這時是由轉動的曲軸和連桿推動活塞)，可燃混合氣被壓縮。當活塞到達上止點時，可燃混合氣被壓縮到有原體積的十分之下甚至更少。Whentheair-fuelmixtureiscompressed,notonlydoesthepressureinthecylindertoup,butthetemperatureofthemixturealsoincreases.當油氣混合燃料被壓縮時，不僅汽缸里的壓力上升，可燃混合氣的溫度也隨之增加了。Powerstroke.AsthepistonreachesTDConthecompressionstroke,andelectricsparkisproducedatthesparkplug.Theignitionsystemdeliversahigh-voltagesurgeofelectricitytothesparkplugtoproducethespark.Thesparkignitestheair-fuelmixture.Itnowbeginstoburnveryrapidly,andthecylinderpressureincreasedtoasmuchas3-5MPaorevenmore.Thisterrificpushagainstthepistonforcesitdownward,andapowerimpulseistransmittedthroughtheconnectingrodtothecrankpinonthecrankshaft.Thecrankshaftisrotatedasthepistonispusheddownbythepressureaboveit.AsthepistonreachesTDConthecompressionstroke,andelectricsparkisproducedatthesparkplug.Theignitionsystemdeliversahigh-voltagesurgeofelectricitytothesparkplugtoproducethespark.當活塞到達壓縮行程的上止點時，火花塞產生電火花。電火花是由點火系統向火花塞提供高壓電脈沖而產生的。

Thesparkignitestheair-fuelmixture.Itnowbeginstoburnveryrapidly,andthecylinderpressureincreasedtoasmuchas3-5MPaorevenmore.

電火花點燃可燃混合氣?？扇蓟旌蠚忾_始發(fā)生劇烈燃燒，氣缸內壓力達到3-5兆帕，甚至更高。Thisterrificpushagainstthepistonforcesitdownward,andapowerimpulseistransmittedthroughtheconnectingrodtothecrankpinonthecrankshaft.Thecrankshaftisrotatedasthepistonispusheddownbythepressureaboveit.作用于活塞上強大的推動力推動活塞向下運動，并將這一推力通過連桿傳到曲軸上的連桿軸頸上。因此，當活塞受壓向下運動時，推動曲軸轉動。Exhauststroke.AsthepistonreachesBDCagain,theexhaustvalveopens.Now,asthepistonmovesupontheexhauststroke,itforcestheburnedgasesoutofthecylinderthroughtheexhaust-valveport.Then,whenthepistonreachesTDC,theexhaustvalveclosedandtheintakevalveopens.Now,afreshchargeofair-fuelmixturewillbedrawnintothecylinderasthepistonmovesdowntowardBDC.Thisfourstrokecycleofpistonwithinthecylinderisrepeatedtimeandagaintoputthevehicleforward.AsthepistonreachesBDCagain,theexhaustvalveopens.Now,asthepistonmovesupontheexhauststroke,itforcestheburnedgasesoutofthecylinderthroughtheexhaust-valveport.當活塞再一次到達下止點時，排氣門打開。同時，活塞向上移動，把廢氣經排氣門排出氣缸。Then,whenthepistonreachesTDC,theexhaustvalveclosedandtheintakevalveopens.Now,afreshchargeofair-fuelmixturewillbedrawnintothecylinderasthepistonmovesdowntowardBDC.隨后活塞達到上止點，排氣門關閉，進氣門打開。當活塞又一次向下移動到達下止點時，新鮮燃混合氣被吸入氣缸。Thisfourstrokecycleofpistonwithinthecylinderisrepeatedagainandagaintoputthevehicleforward.上述的四個行程又繼續(xù)重復，推進車輛前進。strokeBDCTDCsurgeterrificcrankpinintakestrokeCompressionstrokepowerstrokeexhauststrokefreshcharge行程，沖程；上止點；下止點；沖擊，脈動；了不起的，絕妙的；曲柄銷，連桿軸頸；吸氣沖程；壓縮沖程；做功沖程；排氣沖程；吸入的新鮮混合油氣I.TranslatethefollowingsentencesintoChinese.1．Engineisthepowersourceoftheautomobile.Powerisproducedbythelinearmotionofapistoninacylinder.發(fā)動機是汽車的