進(jìn)氣和排氣畢業(yè)課程設(shè)計外文文獻(xiàn)翻譯、中英文翻譯、外文翻譯

1、<p><b>　　外文文獻(xiàn)</b></p><p>　　Intake and ExhaustTuned intake manifoldFirst introduced by Mercedes 300SL in 1954, tuned intake manifold is not exactly a new technology. It is discussed here ju

2、st because its principle is useful to our further study of variable intake manifold.Before 1950s, engineers believed short intake manifolds were the best to engine breathing. Then they discovered that under some conditi

3、ons long intake manifolds could actually improve output, thanks to a so-called "supercharging effect". How is that do</p><p>　　When fresh air is sucked into combustion chamber, it gathers speed and

4、 momentum in the intake manifold. As soon as the inlet valve is closed, the fast-moving air hits the valve and compresses, generating high pressure. With no where to go, this high pressure bounces back, travels along the

5、 intake manifold, hits the plenum at the other side and bounces back again. In this way, the high pressure bounces back and forth along the intake manifold until the inlet valve opens again, creating pressure w</

6、p><p>　　Unfortunately, tuned intake manifold works only across a narrow rev band. If the engine revs beyond that band, the pressure wave will arrive too late in the intake stroke, contributing little to chargin

7、g. If the engine runs below that rev band, the pressure wave will arrive the inlet valve before it opens. In both cases, the low pressure area of pressure wave may even work against cylinder charging, hampering torque ou

8、tput.A sports car engine may employ a shorter tuned intake manifold to optimi</p><p>　　Some early VLIM systems, like this Ford 2.5 Duratec V6, used separate long and short pipes, which is easily visible her

9、e. The short pipes go to the nearest cylinder bank while the long pipes go to the opposite bank. Such arrangement is space engaging. The lack of space leads to narrower pipes used, thus it is not very suitable to high-pe

10、rformance engines.</p><p>　　That is why most VLIM systems, like this one on Honda K20C engine, have their long and short intake paths sharing the same manifolds. At low rpm, the air runs through the long man

11、ifold; At high rpm, a valve opens to a short-cut path, thus the air joins the manifold at later stage. </p><p>　　3-stage variable length intake manifold</p><p>　　If 2 stages are not good en

12、ough to broaden the torque curve, why not use 3 stages ?Shown here is the Audi 4.2-liter 40-valve V8 used in the late 1990s to mid-2000s. Its VLIM system is located inside the V-valley to save space. There are two flaps

13、 inside the system. With both closed, the fresh air runs through the full length of manifold. With one flap opens, the air runs through a short-cut path. With another flap opens, an even shorter path is established. 

14、;The following torque curve shows the</p><p>　　The 3-stage system is a little bit more complicated and space engaging than 2-stage system. It was eventually abandoned when Audi introduced dual-continuous VV

15、T and FSI to broaden the torque curve.</p><p>　　Continuous variable length intake manifold - e.g. BMW DIVA</p><p>　　BMW's DIVA (Differentiated Variable Air Intake) system was first introduce

16、d to the N52 V8 engines on 7-Series in 2001. It is the world's first continuously variable length intake manifold.The principle is simple. The intake manifold of each cylinder is arranged in circular shape and half-

17、recessed into the V-valley. The inner wall is actually a rotor, on which the air inlet is located. When the rotor swivels, the position of the air inlet moves in relation to the outer housing of manifold. This </p>

18、<p>　　Resonance intake manifoldBoxer engines and V-type engines may employ resonance intake manifold to broaden torque curve. Each bank of cylinders are fed by a common plenum chamber through separate pipes. The

19、two plenum chambers are interconnected by two pipes of different diameters. One of the pipes can be closed by a valve controlled by engine management system. The firing order is arranged such that the cylinders breath al

20、ternately from each chamber, creating pressure waves between them. If the</p><p>　　This is the resonance intake system on Porsche 996 GT3. Note that it has 2 pipes connecting between teh 2 plenum chambers.&#

21、160;</p><p>　　Resonance intake system has been used in various Porsches starting from 964 Carrera. In 993, Porsche combined it with an additional variable length manifold to form a 3-stage intake system name

22、s VarioRam. However, the system is very space consuming (see right hand side picture below), so from 996 forward it reverts to the resonance intake system only, although Porsche keeps using the name VarioRam. Honda

23、NSX is another rare application of the resonance intake system. </p><p>　　A: below 5000 rpm: long pipes; resonance intake disabled.B: 5000-5800 rpm: long pipes plus short-pipe resonance intake, with on

24、e interconnected pipe of the resonance intake closed.C: above 5800 rpm: long pipes plus short-pipe resonance intake, with both interconnected pipes of the resonance intake opened.</p><p>　　Tuned Exhaust &am

25、p; Variable Back-Pressure ExhaustThe design of exhaust manifold is not unlike intake manifold. Exhaust gas emits in the form of high-pressure pulse. If you have a micro-analysis on the pulse, you will find the pulse is

26、not always high-pressure. In fact, shortly after the first surge of pressure, there is a period of negative pressure (i.e. lower than atmospheric pressure or 1 bar), as shown in the graph below. Why? Because the gas puls

27、e has mass and momentum. To let you easier to u</p><p>　　If we can collect the exhaust pulses from all cylinders with equal-length exhaust manifolds (or "header"), we will get an evenly distributed

28、 pulse train. Interestingly, this evenly distributed pulse train actually helps sucking exhaust gas out of the combustion chambers, as the low-pressure tail of one pulse sucks the next pulse, so forth. When both intake a

29、nd exhaust valves are opened during the overlapping period, the aforementioned effect even helps sucking fresh air into the combustion chamb</p><p>　　The tuned exhaust manifold (header) on BMW M3 V8. Note th

30、e individual pipes before the collector are long and equal-length.</p><p>　　To get the scavenging effect working, the gas flow should run quick enough in the exhaust manifold. Take our truck example again, i

31、f the truck is cruising slowly on motorway, there is hardly any vacuum effect you can feel. Exhaust gas pulse is the same. To speed up the gas flow, obviously, the best way is to use narrower exhaust pipes throughout the

32、 whole exhaust system - including manifolds, collector and muffler. However, narrower pipes also generate more resistance to gas flow, or what we cal</p><p>　　Principle of variable back-pressure exhaust</

33、p><p>　　The by-pass also changes the sound quality, making it louder and "sportier". Therefore variable back-pressure exhaust is popular on sports cars.</p><p><b>　　進(jìn)氣和排氣</b>&

34、lt;/p><p><b>　　進(jìn)氣歧管</b></p><p>　　首先介紹了梅賽德斯300SL 1954、進(jìn)氣歧管是不是一個新技術(shù)。這里討論的只是因為它的原則是有用的，我們進(jìn)一步研究可變進(jìn)氣歧管。世紀(jì)50年代以前，工程師們認(rèn)為短進(jìn)氣歧管是發(fā)動機(jī)呼吸的最佳選擇。然后，他們發(fā)現(xiàn)，在某些條件下，長進(jìn)氣歧管實際上可以提高產(chǎn)量，由于所謂的“增壓效應(yīng)”。這是怎么做的？讓我們看看下

35、面的插圖： 當(dāng)新鮮空氣吸入燃燒室時，它在進(jìn)氣歧管中聚集速度和動量。當(dāng)入口閥門關(guān)閉時，快速移動的空氣撞擊閥門并壓縮，產(chǎn)生高壓。沒有地方去，這種高壓反彈，沿著進(jìn)氣歧管，擊中在另一側(cè)的全會和反彈回來。這樣，高壓來回沿進(jìn)氣歧管到進(jìn)氣閥再次打開，創(chuàng)建 壓力波。</p><p>　　現(xiàn)在有趣的是：如果進(jìn)氣閥在壓力波回來的時候完全打開，壓力波會因為高壓而幫助燃燒室充電。這與用輕增壓器增壓燃燒室不同，因此我們稱之為增壓效應(yīng)。

36、 </p><p>　　為了匹配閥門開啟的時間，壓力波的頻率應(yīng)與發(fā)動機(jī)轉(zhuǎn)速同步，明顯。這個頻率取決于進(jìn)氣歧管的長度（L在圖中）。長度越長，壓力波恢復(fù)的時間越長，壓力波的頻率越低。其結(jié)果是，較長的進(jìn)氣歧管導(dǎo)致增壓效果在較低的發(fā)動機(jī)轉(zhuǎn)速。較短的歧管導(dǎo)致增壓效應(yīng)在更高的轉(zhuǎn)速。通過選擇合適的歧管長度，我們可以得到所需的功率特性。 </p><p>　　計算發(fā)現(xiàn)，為了實現(xiàn)有益的增壓

37、效果，進(jìn)氣歧管應(yīng)異常長。如果太短，壓力波會在閥門開啟之前多次在歧管中來回跳動，這時高壓會大大降低。因此，調(diào)諧進(jìn)氣歧管應(yīng)該是長的。 </p><p>　　不幸的是，調(diào)諧進(jìn)氣歧管只工作在一個狹窄的轉(zhuǎn)速帶。如果發(fā)動機(jī)轉(zhuǎn)速超過波段，壓力波到達(dá)進(jìn)氣行程太晚，貢獻(xiàn)不充電。如果發(fā)動機(jī)運(yùn)行低于轉(zhuǎn)速帶，壓力波將到達(dá)進(jìn)氣閥打開之前。在這兩種情況下，壓力波的低壓區(qū)甚至可以對氣缸充電，阻礙轉(zhuǎn)矩輸出。

38、 </p><p>　　跑車發(fā)動機(jī)可以采用較短的調(diào)諧進(jìn)氣歧管優(yōu)化其輸出在高轉(zhuǎn)速（費(fèi)用低到中等轉(zhuǎn)速輸出）。與此相反，一個沉重的轎車或商用面包車發(fā)動機(jī)可以選擇一個較長的流形，有利于低轉(zhuǎn)速輸出的價格高轉(zhuǎn)速輸出。正如你所看到的，流形長度的選擇總是一種折衷。這就是為什么許多現(xiàn)代發(fā)動機(jī)轉(zhuǎn)向可變進(jìn)氣歧管…</p><p>　　可變進(jìn)氣歧管（進(jìn)氣） </p>

39、<p>　　自上世紀(jì)90年代中期以來，可變進(jìn)氣歧管在自然吸氣式發(fā)動機(jī)上得到了廣泛的應(yīng)用，主要用于拓寬扭矩曲線，或者提高發(fā)動機(jī)的靈活性。傳統(tǒng)的調(diào)諧進(jìn)氣歧管集中在一個狹窄的轉(zhuǎn)速范圍。與此相反，提供了2個或更多的進(jìn)氣配置階段，以處理不同的發(fā)動機(jī)轉(zhuǎn)速。這聽起來很像可變氣門正時，但一般來說生產(chǎn)成本較低，因為它只涉及一些鑄造或塑料歧管和一些電動閥。這解釋了為什么它被應(yīng)用到更便宜和更小的發(fā)動機(jī)VVT走紅之前。今天，許多發(fā)動機(jī)采用這兩種功能，

40、以達(dá)到最佳效果。 然而，可變進(jìn)氣歧管是很少使用渦輪增壓或增壓引擎-大眾的2 TFSI發(fā)動機(jī)是少數(shù)例外之一。這是因為強(qiáng)迫感應(yīng)已經(jīng)提供了很強(qiáng)的增壓作用。這在很大程度上降低了成本效益，因此其額外的成本和重量難以自圓其說。隨著越來越多的汽車轉(zhuǎn)向渦輪增壓發(fā)動機(jī)，預(yù)計在未來可預(yù)見的未來，汽車的普及將會降溫。有兩種類型：可變長度型和諧振型。 可變長度進(jìn)氣歧管（VLIM） </p><

41、p>　　變長進(jìn)氣歧管是直接調(diào)節(jié)傳統(tǒng)進(jìn)氣歧管的缺點。如果一個固定長度的進(jìn)氣歧管進(jìn)行了優(yōu)化，一個非常狹窄的轉(zhuǎn)速波段，為什么不給它2套進(jìn)氣歧管，一個短管，以高轉(zhuǎn)速，而另一個長管，以低轉(zhuǎn)速？通過使用簡單的蝶閥，長和短管道之間的切換是容易的。 </p><p>　　一些早期的VLIM系統(tǒng)，這樣福特2.5 Duratec V6，用單獨(dú)的長和短的管道，這是很明顯的在這里。短管到最近的氣缸組，而長管

42、轉(zhuǎn)到相反的銀行。這樣的安排是空間嚙合?？臻g的缺乏導(dǎo)致使用的管道變窄，因此它不是非常適合高性能發(fā)動機(jī)。這就是為什么大多數(shù)VLIM系統(tǒng)，像這樣一個在本田K20C引擎，有長、短進(jìn)氣路徑共享同一流形。在低轉(zhuǎn)速時，空氣流經(jīng)長歧管；在高轉(zhuǎn)速時，閥門打開一個捷徑路徑，從而空氣加入歧管在稍后階段。 </p><p>　　三級可變長度進(jìn)氣歧管 </p><p>　　如果2個階段不夠好

43、，以擴(kuò)大扭矩曲線，為什么不使用3個階段？ </p><p>　　這里顯示的是奧迪4.2升40閥V8用在上世紀(jì)90年代末到2000，VLIM系統(tǒng)位于v-valley節(jié)省空間。系統(tǒng)內(nèi)有兩個襟翼。兩個封閉的，新鮮的空氣貫穿歧管的全長。一個皮瓣打開，空氣通過一個捷徑路徑。一瓣打開，一個更短的路徑建立。</p><p>　　以下的扭矩曲線顯示的VLIM 3階段的影響：三級系統(tǒng)

44、是更復(fù)雜一點，空間嚙合比二級系統(tǒng)。最終被放棄，當(dāng)奧迪推出雙連續(xù)可變氣門正時及FSI擴(kuò)大扭矩曲線。連續(xù)可變長度進(jìn)氣歧管-例如寶馬，寶馬的Diva（區(qū)分可變進(jìn)氣）系統(tǒng)首次引入到N52的V8引擎在7系列2001。它是世界上第一個連續(xù)可變長度進(jìn)氣歧管。原理簡單。各缸的進(jìn)氣歧管安裝在圓形和半凹進(jìn)v-valley。內(nèi)壁實際上是一個轉(zhuǎn)子，入口位于其上。當(dāng)轉(zhuǎn)子旋轉(zhuǎn)，在關(guān)系到歧管外殼進(jìn)風(fēng)口移動位置。這不同的進(jìn)氣管的有效長度，從最大673毫米至231毫米。

45、 低于3500轉(zhuǎn)，使用最大的流形長度優(yōu)化低端扭矩。超過3500轉(zhuǎn)，轉(zhuǎn)速逐漸降低根據(jù)長度，保持在最佳水平 增壓效果。作為主角需要一個圓形建筑，它占用更多的空間（特別是高度）比其他VLIM系統(tǒng)。這阻止它成為流行。就連寶馬本身也不熱衷于這項技術(shù)。當(dāng)4.4升V8引擎擴(kuò)大到4.8升，其額外的扭矩允許寶馬為簡單兩VLIM系統(tǒng)放棄DIVA。下一代V8甚至切換到渦輪增壓，所以女主角沒有希望返回。今天，它仍然是唯一的連續(xù)可變進(jìn)氣

46、歧管以往任何時候都生產(chǎn)。 </p><p>　　諧振進(jìn)氣歧管 </p><p>　　拳擊手發(fā)動機(jī)和V型發(fā)動機(jī)可以采用共振進(jìn)氣歧管擴(kuò)大扭矩曲線。每個氣缸由一個共同的增壓室通過單獨(dú)的管道供給。由兩個不同直徑的管道相互連接的兩個增壓室。其中一個管路可由發(fā)動機(jī)管理系統(tǒng)控制的閥門關(guān)閉。點火順序布置使氣缸從每個腔室交替地呼吸，在它們之間產(chǎn)生壓力波。如果壓力波的頻率匹配轉(zhuǎn)速，它可

47、以幫助填充氣缸，從而提高了呼吸效率。由于頻率也取決于互連管的橫截面面積，通過關(guān)閉其中一個在低轉(zhuǎn)速，面積以及頻率降低，從而提高輸出在較低轉(zhuǎn)速。在高轉(zhuǎn)速時，閥門打開，從而提高了高速氣缸灌裝。 </p><p>　　這是保時捷996 GT3的諧振進(jìn)氣系統(tǒng)。注意，它有2管，2室之間的連接。 </p><p>　　諧振進(jìn)氣系統(tǒng)已經(jīng)廣泛應(yīng)用于各種保時捷從9

48、64 Carrera。993，保時捷將其與一個額外的可變長度的歧管形成三級進(jìn)氣系統(tǒng)的名字 varioram。然而，該系統(tǒng)消耗的空間（見右下圖），所以從996轉(zhuǎn)發(fā)回復(fù)只有諧振進(jìn)氣系統(tǒng)，雖然保時捷一直使用的名稱varioram。本田NSX是諧振進(jìn)氣系統(tǒng)的另一種罕見的應(yīng)用。 保時捷varioram系統(tǒng)993 </p><p>　　答：低于5000轉(zhuǎn)：長管；共振進(jìn)氣禁用。

49、 </p><p>　　B：5000-5800轉(zhuǎn)：長管加短管諧振進(jìn)氣，一連接管的諧振進(jìn)氣關(guān)閉。 </p><p>　　C：5800轉(zhuǎn)以上：長管加短管共振進(jìn)氣，兩個相互連接的管道的共振口打開。 </p><p>　　調(diào)整排氣和可變背壓排氣 </p><p>　　排氣歧管的設(shè)計

50、與進(jìn)氣歧管不同。廢氣以高壓脈沖的形式排出。如果你對脈搏有一個微觀的分析，你會發(fā)現(xiàn)脈搏并不總是高壓的。事實上，在第一次壓力激增后不久，有一段負(fù)壓（即低于大氣壓力或1巴），如下圖所示。為什么？由于氣體脈沖具有質(zhì)量和動量。為了讓你更容易理解，想象的氣體脈沖作為一個大卡車運(yùn)行在公路上，你站在路邊。當(dāng)卡車經(jīng)過你的時候，你的頭發(fā)很可能被拖到公路上，因為卡車后面有一個低壓區(qū)域?？ㄜ囘\(yùn)行速度越快，壓力越低。 </p>

51、<p>　　如果我們可以收集所有的排氣管的排氣脈沖相同長度的排氣歧管（或“頭”），我們將得到一個均勻分布的脈沖串。有趣的是，這種均勻分布的脈沖串實際上有助于吸入廢氣的燃燒室，作為一個脈沖的低壓尾吸下一個脈沖，所以。當(dāng)進(jìn)氣閥和排氣閥在重疊期間打開時，上述效果甚至有助于吸入新鮮空氣進(jìn)入燃燒室。其結(jié)果是，這種效應(yīng)被稱為“反向增壓”或“清除”。 </p><p>　　為了充分利用掃氣

52、效果，必須采用等長排氣歧管。此外，減少各缸的排氣脈沖之間的干擾，個人管應(yīng)長。這解釋了為什么大多數(shù)賽車發(fā)動機(jī)和高性能發(fā)動機(jī)采用調(diào)整排氣歧管與非常長和奇怪的路由管道。 調(diào)整排氣歧管（頭）寶馬M3 V8。注意收集器前的各個管子長而等長。 </p><p>　　為了達(dá)到清除效果，排氣歧管中的氣體流量應(yīng)足夠快。再次乘坐我們的卡車的例子，如果卡車在高速公路上緩慢巡航，幾乎沒有任

53、何真空效果，你可以感受到。排氣脈沖相同。為了加速氣流，顯然，最好的方法是在整個排氣系統(tǒng)中使用窄排氣管，包括歧管、收集器和消聲器。然而，狹窄的管道也會產(chǎn)生更多的氣體流動阻力，或者我們稱之為“背壓”。在高轉(zhuǎn)速的廢氣率是巨大的，背壓將大到足以超過清除效果的好處。因此，窄的排氣管只有利于低轉(zhuǎn)速輸出。與此相反，大直徑排氣管降低背壓在高轉(zhuǎn)速，提高頂端功率，但在低轉(zhuǎn)速的廢氣流量太慢，以產(chǎn)生清除效果，所以它的輸出在低轉(zhuǎn)速。這就是為什么許多性能車選擇 可