Chapter3Engine(2.6)

1、SEASpecial English for AutomobileChapter 2 internal combustion engineReview 1: Whats the meaning of the air/fuel ratio (A/F)? The proportion of air to fuel.*A/F is stated in term of weight, different fuel has different ratio.SEASpecial English for AutomobileChapter 2 internal combustion engine1)Gaso

2、line : Gasoline must vaporize easily. This characteristic, called volatility, is important. However, it must not vaporize too easily, or it will turn to vapor inside the fuel tank or fuel lines. Inside the fuel line, fuel vapor may block the flow of liquid gasoline. This is called vapor lock. Vapor

3、lock is common in fuel lines where the inlet side of the pump is exposed to high temperatures.汽油應(yīng)易于蒸發(fā)，這個(gè)重要的特性稱為揮發(fā)性。但是汽油也不汽油應(yīng)易于蒸發(fā)，這個(gè)重要的特性稱為揮發(fā)性。但是汽油也不能揮發(fā)得過快，不然它會在油箱或油管里轉(zhuǎn)變?yōu)檎魵狻Ｔ谟凸苣軗]發(fā)得過快，不然它會在油箱或油管里轉(zhuǎn)變?yōu)檎魵狻Ｔ谟凸苤衅驼魵鈺璧K液態(tài)汽油的流動，這稱為氣阻。汽油泵的入中汽油蒸氣會阻礙液態(tài)汽油的流動，這稱為氣阻。汽油泵的入口處承受著高溫，就經(jīng)常出現(xiàn)氣阻?？谔幊惺苤邷兀徒?jīng)常出現(xiàn)氣阻。SEASpecial E

4、nglish for AutomobileChapter 2 internal combustion engineIncreasing the pressure of the fuel mixture in the combustion chamber before ignition helps to increase the power of an engine. This is done by compressing the fuel mixture to a smaller volume. Higher compression ratios not only boost power bu

5、t also give more efficient power. But as the compression ratio goes up, knocking tendency increases. 在點(diǎn)火前增加燃燒室內(nèi)可燃混合氣的壓力有助于提高發(fā)動機(jī)的在點(diǎn)火前增加燃燒室內(nèi)可燃混合氣的壓力有助于提高發(fā)動機(jī)的功率，這是通過把可燃混合氣壓縮到一個(gè)極小的體積來實(shí)現(xiàn)的功率，這是通過把可燃混合氣壓縮到一個(gè)極小的體積來實(shí)現(xiàn)的。高的壓縮比不僅增加發(fā)動機(jī)的功率，而且會帶來更多的有效。高的壓縮比不僅增加發(fā)動機(jī)的功率，而且會帶來更多的有效功率。但隨著壓縮比的增加，爆震的可能性也會增加。功率。但隨著壓縮比的增加，

6、爆震的可能性也會增加。2) gasoline:SEASpecial English for AutomobileChapter 2 internal combustion engine3) gasoline: Two primary standard reference fuels, normal heptane and iso-octane arbitrarily assigned 0 and 100 octane number, respectively, are then blended to produce the same knock intensity as the test sa

7、mple. The percentage of isooctane in blend is considered the octane number of the test sample. Thus, if the matching reference blend is made up of 15% n-heptane and 85% isooctane, the test sample is rated 85 motor or research octane number, according to the test method used.兩種基準(zhǔn)參考燃料正庚烷和異辛烷分別被定義成辛烷值為

8、兩種基準(zhǔn)參考燃料正庚烷和異辛烷分別被定義成辛烷值為0 0和辛烷和辛烷值為值為100100，將它們混合產(chǎn)生與實(shí)驗(yàn)樣本相等敲缸強(qiáng)度的爆震?；旌?，將它們混合產(chǎn)生與實(shí)驗(yàn)樣本相等敲缸強(qiáng)度的爆震?；旌衔镏挟愋镣榈陌俜直染驼J(rèn)為是實(shí)驗(yàn)樣本的辛烷值。這樣，依照實(shí)物中異辛烷的百分比就認(rèn)為是實(shí)驗(yàn)樣本的辛烷值。這樣，依照實(shí)驗(yàn)方法，如果匹配的混合物由驗(yàn)方法，如果匹配的混合物由15%15%的正庚烷和的正庚烷和85%85%異辛烷組成，那異辛烷組成，那么按照所用的實(shí)驗(yàn)方法，對比實(shí)驗(yàn)樣本的辛烷值就是么按照所用的實(shí)驗(yàn)方法，對比實(shí)驗(yàn)樣本的辛烷值就是8585。SEASpecial English for AutomobileChap

9、ter 2 internal combustion engineBasic words(1):fuel tankfuel tank油箱油箱fuel filterfuel filter汽油濾清器汽油濾清器fuel pumpfuel pump汽油泵汽油泵Carburetor (mix)Carburetor (mix)化油器化油器air air filterfilter空氣空氣濾清器濾清器burnSEASpecial English for AutomobileChapter 2 internal combustion engineFuel tankFuel linefuel pumpFuel fi

10、ltercarburetorair filterSEASpecial English for AutomobileChapter 2 internal combustion engine4) Fuel pump: Most cars today have a mechanical fuel pump. This pumps fuel out of the tank and through the fuel lines to the carburetor or injection system. In most cars, the pump is mounted on the engine bl

11、ock. Some cars have an electric fuel pump. This pump mounts in the fuel tank with the fuel pickup and the fuel-gauge-sending unit. 當(dāng)前大多數(shù)汽車采用機(jī)械汽油泵，汽油泵從油箱抽出當(dāng)前大多數(shù)汽車采用機(jī)械汽油泵，汽油泵從油箱抽出汽油，通過油管送到化油器或噴射系統(tǒng)。大部分汽車汽油，通過油管送到化油器或噴射系統(tǒng)。大部分汽車的汽油泵安裝在缸體上。一些汽車采用電動汽油泵，的汽油泵安裝在缸體上。一些汽車采用電動汽油泵，汽油泵安裝在油箱上，附帶有油量傳感器和燃油表油汽油泵安裝在油箱

12、上，附帶有油量傳感器和燃油表油量傳送裝置。量傳送裝置。SEASpecial English for AutomobileChapter 2 internal combustion enginediaphragm springdiaphragm springRocker armRocker arminlet portinlet portoutlet portoutlet portdiaphragmdiaphragm5) Fuel pump: The rotation of the lobe moves a rocker arm in the pump. Inside the pump, a fl

13、exible diaphragm connects to the rocker arm though a diaphragm spring, pull rod and link.凸圓旋轉(zhuǎn)帶動油泵凸圓旋轉(zhuǎn)帶動油泵中的搖臂運(yùn)動。油中的搖臂運(yùn)動。油泵中可變形的泵膜泵中可變形的泵膜通過膜片回位彈簧通過膜片回位彈簧和膜片拉桿機(jī)構(gòu)與和膜片拉桿機(jī)構(gòu)與搖臂相連。搖臂相連。SEASpecial English for AutomobileChapter 2 internal combustion engineSEASpecial English for AutomobileChapter 2 internal

14、combustion engineBasic words(2):Excess-air factor :Complete burnRich mixture Lean mixture濃混合氣濃混合氣 稀混合氣稀混合氣theoretical requirement(14.7:1) =air mass supplied/ theoretical requirement過量空氣系數(shù)過量空氣系數(shù)SEASpecial English for AutomobileChapter 2 internal combustion engineOperating conditions:1)Cold star2)post

15、-start phase3)warm-up4)Acceleration5)Part load6)Full load7)Idling8)Overrun9)engine-speed limiting10)High altitudes1)冷啟動冷啟動2)后啟動階段后啟動階段3)暖機(jī)暖機(jī)4)加速加速5)部分負(fù)荷部分負(fù)荷6)全負(fù)荷全負(fù)荷7)怠速怠速8)超速超速9)發(fā)動機(jī)限速發(fā)動機(jī)限速10)高海拔高海拔SEASpecial English for AutomobileChapter 2 internal combustion engineReview 2: List the main function o

16、f the carburetor. Meteringcorrect proportions of fuel and airAtomizationspray of fine particles to great airDistributionuniform mixture delivered to manifoldSEASpecial English for AutomobileChapter 2 internal combustion engineReview 3: List the main circuits of the carburetor. Idle and Low-Speed Cir

17、cuitMain Metering CircuitPower-Enrichment CircuitAccelerator (Pump) CircuitChoke CircuitSEASpecial English for AutomobileChapter 2 internal combustion engineSEASpecial English for AutomobileChapter 2 internal combustion engineBasic words():needle valve 針針閥閥float chamber 浮子室浮子室float 浮子浮子 venturi 喉管喉管

18、discharge tube 噴管噴管throttle 節(jié)氣門節(jié)氣門jet量量孔孔idling valve idling valve 怠速閥怠速閥nozzlenozzle 噴嘴噴嘴advance angleadvance angle提前角提前角dwell angledwell angle 持續(xù)角持續(xù)角PetroleumPetroleum 石油石油SEASpecial English for AutomobileChapter 2 internal combustion engineSEASpecial English for AutomobileChapter 2 internal combu

19、stion engine6) carburetor: A carburetor delivers fuel in proportion to the amount of air flowing through it. As you press on the accelerator pedal, the throttle valve opens wider to draw more air through the carburetor. The carburetor provides richer or leaner mixtures, depending on a number of fact

20、ors: engine speed, load, temperature, and throttle position. To meet complicated demands, a carburetor is a highly intricate device, with many internal passages and parts. 化油器輸送的燃油與流經(jīng)化油器的空氣量成一定比例。踩下加速化油器輸送的燃油與流經(jīng)化油器的空氣量成一定比例。踩下加速踏板，節(jié)氣門開度變大，化油器吸入的空氣增加?；推骺商峁┨ぐ?，節(jié)氣門開度變大，化油器吸入的空氣增加?；推骺商峁┹^濃或較稀的混合氣，這取決于發(fā)動

21、機(jī)轉(zhuǎn)速、負(fù)荷、溫度和油門較濃或較稀的混合氣，這取決于發(fā)動機(jī)轉(zhuǎn)速、負(fù)荷、溫度和油門開度等因素。為滿足復(fù)雜的要求，化油器的結(jié)構(gòu)也很復(fù)雜，其上開度等因素。為滿足復(fù)雜的要求，化油器的結(jié)構(gòu)也很復(fù)雜，其上有很多內(nèi)部通道和部件。有很多內(nèi)部通道和部件。SEASpecial English for AutomobileChapter 2 internal combustion engine7) carburetor: An automobile carburetor is designed with a venturi chamber. The venturi is simply a narrowed port

22、ion in the air passage. Air moving through the throat of the carburetor speeds up as it travels through this narrowed passageway. The increased air speed through the venturi creates a low-pressure area at the opening of the fuel nozzle. Atmospheric pressure pushes down on a fuel reservoir within the

23、 carburetor known as the float chamber. Fuel is forced through a tube that extends into the low-pressure area of the venturi. Thus, fuel sprays through the end of the tube into the air stream. 化油器設(shè)計(jì)成帶有喉管的形式，喉管是空氣通道中一化油器設(shè)計(jì)成帶有喉管的形式，喉管是空氣通道中一段狹窄的部分。空氣流過化油器的喉管時(shí)速度增加，段狹窄的部分?？諝饬鬟^化油器的喉管時(shí)速度增加，在噴嘴的開口處形成低壓區(qū)。大氣

24、壓力作用在儲存汽在噴嘴的開口處形成低壓區(qū)。大氣壓力作用在儲存汽油的浮子室上。燃油便被壓入伸向喉管低壓區(qū)的噴管油的浮子室上。燃油便被壓入伸向喉管低壓區(qū)的噴管里。這樣燃油從噴管末端噴射到氣流中。里。這樣燃油從噴管末端噴射到氣流中。SEASpecial English for AutomobileChapter 2 internal combustion engineSEASpecial English for AutomobileChapter 2 internal combustion engine8) carburetor: The float chamber is a reservoir f

25、or storing and supplying fuel to the carburetor. As the engine uses fuel, the float chamber replenishes it automatically. The float chamber works on the same basic principle as the holding tank in a flushing toilet. A float rests on top of the fuel in the reservoir. As fuel is used, the float level

26、drops. When the float drops, a needle valve is opened. 浮子室用于儲存燃油以及向化油器提供燃油。發(fā)動機(jī)消浮子室用于儲存燃油以及向化油器提供燃油。發(fā)動機(jī)消耗燃油時(shí)，浮子室會自動進(jìn)行補(bǔ)充。浮子室和抽水馬桶耗燃油時(shí)，浮子室會自動進(jìn)行補(bǔ)充。浮子室和抽水馬桶儲水箱的工作原理是相同的。浮子停留在浮子室的油面儲水箱的工作原理是相同的。浮子停留在浮子室的油面上。消耗燃油時(shí)，浮子下落。浮子下落時(shí)，針閥打開。上。消耗燃油時(shí)，浮子下落。浮子下落時(shí)，針閥打開。SEASpecial English for AutomobileChapter 2 internal c

27、ombustion engine9) carburetor: The pressure differential between the float chamber and the venturi causes fuel to flow. However, to maintain the proper air-fuel ratio, the carburetor must provide just the right amount of fuel. To do so, the main discharge tube has a small hole (called a jet or main

28、jet). This allows a precise amount of fuel to enter the airstream. In most cases, this small hole is in the float chamber at the end of the main discharge tube. There, its small size limits fuel flow.浮子室和喉管之間的壓力差引起燃油的流動。然而，為維持合適浮子室和喉管之間的壓力差引起燃油的流動。然而，為維持合適的空燃比，化油器必須提供適量的燃油。為此，在主噴管上有一的空燃比，化油器必須提供適量的燃

29、油。為此，在主噴管上有一個(gè)小孔，稱作量孔或主量孔，它使得精確數(shù)量的燃油進(jìn)入到氣流個(gè)小孔，稱作量孔或主量孔，它使得精確數(shù)量的燃油進(jìn)入到氣流中。量孔一般在主噴管末端的浮子室里，控制著燃油的流量。中。量孔一般在主噴管末端的浮子室里，控制著燃油的流量。SEASpecial English for AutomobileChapter 2 internal combustion engine10)throttle mechanism: The throttle mechanism controls the flow of the air-fuel mixture. The throttle has sev

30、eral parts, including the throttle shaft and the throttle plate. By opening and closing, the throttle plate controls the flow of the air-fuel mixture into the engine. More air flows in as the plate opens; less air flows in as the plate closes. 節(jié)氣門機(jī)構(gòu)控制著可燃混合氣的流量，包節(jié)氣門機(jī)構(gòu)控制著可燃混合氣的流量，包括節(jié)氣門軸和節(jié)氣門等部件。節(jié)氣門的開括節(jié)

31、氣門軸和節(jié)氣門等部件。節(jié)氣門的開啟和關(guān)閉控制著可燃混合氣進(jìn)入發(fā)動機(jī)的啟和關(guān)閉控制著可燃混合氣進(jìn)入發(fā)動機(jī)的流量。節(jié)氣門開啟，空氣流量增加；節(jié)氣流量。節(jié)氣門開啟，空氣流量增加；節(jié)氣門關(guān)閉，空氣流量減少。門關(guān)閉，空氣流量減少。SEASpecial English for AutomobileChapter 2 internal combustion engine11) Gasoline direct injection（GDI）: Conventional gasoline engines are designed to use an electronic fuel injection system

32、, replacing the traditional mechanical carburetion system. Multi-point injection (MPI), where the fuel is injected through each intake port, is currently one of the most wider used systems. Although MPI provides a drastic improvement in response and combustion quality, it is still limited due to fuel and air mixing prior to entering cyli