外文翻譯----柴油機(jī)的工作原理

1、<p>　　A diesel engine works</p><p>　　【Abstract】In diesel engine cylinder, the piston part of the cycle in the compressed gases, and in another part of the work cycle of the combustion gas mixture within

2、 the cylinder so the piston top surface expansion high pressure (about 116 ~ 120Kgf/cm2)under high temperature (about 569°C) gas role, and the pressure through the piston pin, connecting rod to the crankshaft. Can b

3、e seen that the piston is a long time under high temperature and high pressure in continuous reciprocating motion of the</p><p>　　Keywords: Piston; Technology; processing equipment; cutting; Fixture</p>

4、;<p>　　Any type of machine that obtains mechanicalenergy directly from the expenditure of the chemical energy of fuel burned in a combustion chamber that is an integral part of the engine. Four principal types of

5、internal-combustion engines are in general use: the Otto-cycle engine, the diesel engine, the rotary engine, and the gas turbine. For the various types of engines employing the principle of jet propulsion, see Jet Propul

6、sion; Rocket. The Otto-cycle engine, named after its inventor, the German </p><p>　　The fuel supply system of an internal-combustion engine consists of a tank, a fuel pump, and a device for vaporizing or ato

7、mizing the liquid fuel. In Otto-cycle engines this device is either a carburetor or, more recently, a fuel-injection system. In most engines with a carburetor, vaporized fuel is conveyed to the cylinders through a branch

8、ed pipe called the intake manifold and, in many engines, a similar exhaust manifold is provided to carry off the gases produced by combustion. The fuel is ad</p><p>　　In all engines some means of igniting th

9、e fuel in the cylinder must be provided. For example, the ignition system of Otto-cycle engines described below consists of a source of low-voltage, direct-current electricity that is connected to the primary of a transf

10、ormer called an ignition coil. The current is interrupted many times a second by an automatic switch called the timer. The pulsations of the current in the primary induce a pulsating, high-voltage current in the secondar

11、y. The high-voltage </p><p>　　Because of the heat of combustion, all engines must be equipped with some type of cooling system. Some aircraft and automobile engines, small stationary engines, and outboard mo

12、tors for boats are cooled by air. In this system the outside surfaces of the cylinder are shaped in a series of radiating fins with a large area of metal to radiate heat from the cylinder. Other engines are water-cooled

13、and have their cylinders enclosed in an external water jacket. In automobiles, water is circulated thro</p><p>　　Unlike steam engines and turbines, internal-combustion engines develop no torque when starting

14、, and therefore provision must be made for turning the crankshaft so that the cycle of operation can begin. Automobile engines are normally started by means of an electric motor or starter that is geared to the crankshaf

15、t with a clutch that automatically disengages the motor after the engine has started. Small engines are sometimes started manually by turning the crankshaft with a crank or by pulling a </p><p>　　The ordinar

16、y Otto-cycle engine is a four-stroke engine; that is, in a complete power cycle, its pistons make four strokes, two toward the head (closed head) of the cylinder and two away from the head. During the first stroke of the

17、 cycle, the piston moves away from the cylinder head while simultaneously the intake valve is opened. The motion of the piston during this stroke sucks a quantity of a fuel and air mixture into the combustion chamber. Du

18、ring the next stroke, the piston moves toward the</p><p>　　The efficiency of a modern Otto-cycle engine is limited by a number of factors, including losses by cooling and by friction. In general, the efficie

19、ncy of such engines is determined by the compression ratio of the engine. The compression ratio (the ratio between the maximum and minimum volumes of the combustion chamber) is usually about 8 to 1 or 10 to 1 in most mod

20、ern Otto-cycle engines. Higher compression ratios, up to about 15 to 1, with a resulting increase of efficiency, are possible with t</p><p>　　Theoretically, the diesel cycle differs from the Otto cycle in th

21、at combustion takes place at constant volume rather than at constant pressure. Most diesels are also four-stroke engines but they operate differently than the four-stroke Otto-cycle engines. The first, or suction, strok

22、e draws air, but no fuel, into the combustion chamber through an intake valve. On the second, or compression, stroke the air is compressed to a small fraction of its former volume and is heated to approximately 440°

23、</p><p>　　The efficiency of the diesel engine, which is in general governed by the same factors that control the efficiency of Otto-cycle engines, is inherently greater than that of any Otto-cycle engine and

24、 in actual engines today is slightly more than 40 percent. Diesels are, in general, slow-speed engines with crankshaft speeds of 100 to 750 revolutions per minute (rpm) as compared to 2500 to 5000 rpm for typical Otto-cy

25、cle engines. Some types of diesel, however, have speeds up to 2000 rpm. Because die</p><p>　　By suitable design it is possible to operate an Otto-cycle or diesel as a two-stroke or two-cycle engine with a po

26、wer stroke every other stroke of the piston instead of once every four strokes. The power of a two-stroke engine is usually double that of a four-stroke engine of comparable size.</p><p>　　The general princi

27、ple of the two-stroke engine is to shorten the periods in which fuel is introduced to the combustion chamber and in which the spent gases are exhausted to a small fraction of the duration of a stroke instead of allowing

28、each of these operations to occupy a full stroke. In the simplest type of two-stroke engine, the poppet valves are replaced by sleeve valves or ports (openings in the cylinderwall that are uncovered by the piston at the

29、end of its outward travel). In the two-str</p><p>　　In the 1950s the German engineer Felix Wankel developed an internal-combustion engine of a radically new design, in which the piston and cylinder were repl

30、aced by a three-cornered rotor turning in a roughly oval chamber. The fuel-air mixture is drawn in through an intake port and trapped between one face of the turning rotor and the wall of the oval chamber. The turning of

31、 the rotor compresses the mixture, which is ignited by a spark plug. The exhaust gases are then expelled through an exhaust p</p><p>　　A modification of the conventional spark-ignition piston engine, the str

32、atified charge engine is designed to reduce emissions without the need for an exhaust-gas recirculation system or catalytic converter. Its key feature is a dual combustion chamber for each cylinder, with a prechamber tha

33、t receives a rich fuel-air mixture while the main chamber is charged with a very lean mixture. The spark ignites the rich mixture that in turn ignites the lean main mixture. The resulting peak temperature is </p>

34、<p><b>　　柴油機(jī)的工作原理</b></p><p>　　【摘要】在柴油機(jī)氣缸內(nèi)，活塞在一部分工作循環(huán)壓縮氣體，而在另一部分工作循環(huán)氣缸內(nèi)混合氣體燃燒膨脹使活塞頂面承受高溫（約569°C）高壓（約116～120Kgf/cm2）氣體的作用，并把壓力通過(guò)活塞銷(xiāo)、連桿傳給曲軸。可見(jiàn)，活塞是在高溫高壓下作長(zhǎng)時(shí)間連續(xù)變負(fù)荷的往復(fù)運(yùn)動(dòng)，它的負(fù)荷和工作環(huán)境很惡劣。在本設(shè)計(jì)中將對(duì)

35、活塞的加工工藝進(jìn)行設(shè)計(jì)，以保證活塞長(zhǎng)久穩(wěn)定工作?，F(xiàn)將設(shè)計(jì)中所做的工作簡(jiǎn)要介紹如下：柴油機(jī)活塞加工工藝合理性是很重要的，通過(guò)對(duì)零件的作用及工藝方案分析，擬定毛坯的制造形式及工藝路線，通過(guò)分析、比較，采用了相對(duì)集中加工工藝方案，最終確定比較合理的機(jī)械加工工藝路線。制定工藝路線時(shí)主要考慮粗、精加工安排、加工方法選擇、工序集中與分散、加工順序等方面的要求。接著確定加工余量、工序尺寸，經(jīng)過(guò)對(duì)工序特點(diǎn)的分析，恰當(dāng)選擇相應(yīng)加工設(shè)備和工藝裝備。接下來(lái)經(jīng)

36、過(guò)計(jì)算查表確定活塞各主要工序的切削用量并繪制工序卡片，最后設(shè)計(jì)夾具。設(shè)計(jì)夾具時(shí)，要多方面考慮，嚴(yán)格要求，機(jī)床夾具的好壞直接影響工件加工表面的位置精度。所以，機(jī)床夾具設(shè)計(jì)是裝備設(shè)計(jì)中的一項(xiàng)重要的工作，是加工過(guò)程中最活躍的因素之一。在本畢業(yè)設(shè)計(jì)中特別設(shè)計(jì)了</p><p>　　關(guān)鍵字：活塞；工藝路線；加工設(shè)備；切削用量；夾具</p><p>　　任何通過(guò)燃料在氣缸中燃燒，使燃油的化學(xué)能轉(zhuǎn)化為機(jī)

37、械能，從而獲得動(dòng)力的引擎都成為內(nèi)燃機(jī)。最常見(jiàn)的內(nèi)燃機(jī)有四種：奧托循環(huán)式發(fā)動(dòng)機(jī)，柴油機(jī)，轉(zhuǎn)子發(fā)動(dòng)機(jī)和煤氣機(jī)。根據(jù)這四種發(fā)動(dòng)機(jī)的優(yōu)點(diǎn)，把它們應(yīng)用于不同的工況。奧托循環(huán)式發(fā)動(dòng)機(jī)，是根據(jù)其發(fā)明者，德國(guó)機(jī)械師尼古拉斯.奧格事特.奧托的名字來(lái)命名的。是飛機(jī)上很常見(jiàn)的一種發(fā)動(dòng)機(jī)；而柴油機(jī)是由法籍德國(guó)工程師Rudolf Christian Karl Diesel命名的。它是一種用柴油作為燃料的先進(jìn)的發(fā)動(dòng)機(jī)。普遍用在電子控機(jī)械、戰(zhàn)斗機(jī)、公共汽車(chē)、貨車(chē)以及

38、一些小車(chē)上。奧托式發(fā)動(dòng)機(jī)和柴油機(jī)的工作方式都是二沖程或者四沖程。</p><p>　　奧托式發(fā)動(dòng)機(jī)和柴油機(jī)的基本構(gòu)造都是一樣的。壓縮燃燒室是由一個(gè)一段由缸蓋另一端由活塞之間的空間所形成?；钊纳舷逻\(yùn)動(dòng)使得氣缸與活塞間的空間發(fā)生大小變化，從而改變壓縮空間的大小。活塞與曲軸之間通過(guò)連桿相互連接。曲軸將活塞的運(yùn)動(dòng)轉(zhuǎn)化成旋轉(zhuǎn)式的運(yùn)動(dòng)。多氣缸式發(fā)動(dòng)機(jī)的曲軸，在每一個(gè)氣缸處都會(huì)多一個(gè)稱(chēng)為曲拐的結(jié)構(gòu)部分。這樣每個(gè)氣缸的動(dòng)力才能

39、很好的傳遞給曲軸，是曲軸的轉(zhuǎn)動(dòng)平穩(wěn)。曲軸上接有飛輪并有平衡坑。這樣能夠使曲軸運(yùn)動(dòng)的慣性最小化，達(dá)到平衡的目的。不同的發(fā)動(dòng)機(jī)會(huì)有一個(gè)到二十四個(gè)等的氣缸。</p><p>　　內(nèi)燃機(jī)的燃料供給系統(tǒng)又油箱、油泵、和分油管以及使液體燃料霧化的機(jī)構(gòu)組成。在奧托式發(fā)動(dòng)機(jī)上，并不是靠化油器來(lái)進(jìn)行燃油霧化的，而是利用燃油的直接噴入，一直到現(xiàn)在都是如此。在大多數(shù)發(fā)動(dòng)機(jī)上，燃料都是通過(guò)化油器霧化后通過(guò)壓氣機(jī)進(jìn)入進(jìn)氣管道。在部分發(fā)動(dòng)機(jī)

40、的排氣系統(tǒng)中，也會(huì)用到類(lèi)似的裝置來(lái)通過(guò)利用廢氣的能量對(duì)進(jìn)氣充量進(jìn)行壓縮。燃料平均分配給各個(gè)汽缸，而廢氣則通過(guò)排氣門(mén)排出。進(jìn)排氣門(mén)的開(kāi)閉都是通過(guò)凸輪軸的轉(zhuǎn)動(dòng)從而牽動(dòng)氣門(mén)彈簧作用到挺桿，在正確的時(shí)間是氣門(mén)開(kāi)閉。在上世紀(jì)80年代，缸內(nèi)直噴技術(shù)開(kāi)始用于內(nèi)燃機(jī)領(lǐng)域，從很大程度上代替了傳統(tǒng)的燃油與空氣相混合的技術(shù)。在有直噴裝置的發(fā)動(dòng)機(jī)上，燃料會(huì)通過(guò)噴射系統(tǒng)在正確的時(shí)刻噴入汽缸或者進(jìn)氣管。這樣燃料就會(huì)在汽缸里混合，這比化油器混合更充分，污染更小。&l

41、t;/p><p>　　所有的發(fā)動(dòng)機(jī)上，火花塞的位置都必須適宜。比如奧托式發(fā)動(dòng)機(jī)的點(diǎn)火系統(tǒng)包括低壓電源，即具有變壓性質(zhì)的初級(jí)線圈，從而導(dǎo)出直流電。電流會(huì)被一個(gè)機(jī)械式的定時(shí)調(diào)節(jié)器在一秒鐘內(nèi)方向發(fā)生多次變化。初級(jí)線圈中電流的擾動(dòng)會(huì)產(chǎn)生脈沖，從而會(huì)在次級(jí)線圈中產(chǎn)生高壓電流。這個(gè)高壓電流會(huì)被分電器分配到各個(gè)汽缸，件叫做火花，一個(gè)安裝在汽缸頂部被叫做火花塞的零件。在火花塞末端的兩極間有一個(gè)間隙，高壓電流會(huì)擊穿這個(gè)點(diǎn)火間隙，從而點(diǎn)

42、燃汽缸中的混合氣體。由于燃燒室的溫度太高，所有的發(fā)動(dòng)機(jī)都必須有相應(yīng)的冷卻系統(tǒng)。一些飛機(jī)、汽車(chē)、和船只上的舷外發(fā)動(dòng)機(jī)采用風(fēng)冷。這些采用風(fēng)冷的發(fā)動(dòng)機(jī)都必須有很多散熱片，一邊有較大的散熱面積，從而很好的帶走汽缸的熱量。除此之外的還有水冷系統(tǒng)，它是在發(fā)動(dòng)機(jī)的汽缸中設(shè)有水套來(lái)達(dá)到冷卻的目的。在汽車(chē)上，冷卻液借助水泵的壓力在水套中流動(dòng)，帶走熱量。還有一些汽車(chē)是利用風(fēng)冷，海上船只則是用海水作為冷卻的介質(zhì)。與蒸汽機(jī)和渦輪機(jī)不同，內(nèi)燃機(jī)在發(fā)動(dòng)時(shí)并不會(huì)產(chǎn)生