喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢QQ:414951605或者1304139763 ======================== 喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢QQ:414951605或者1304139763 ======================== 密 級(jí) 分類號(hào) 編 號(hào) 成 績(jī) 本科生畢業(yè)設(shè)計(jì) (論文) 外 文 翻 譯 原 文 標(biāo) 題 Discussion on automobile transmission 譯 文 標(biāo) 題 淺談汽車變速器 作者所在系別 機(jī)電工程學(xué)院 作者所在專業(yè) 車輛工程 作者所在班級(jí) B13142 作 者 姓 名 崔浩男 作 者 學(xué) 號(hào) 201322397 指導(dǎo)教師姓名 焦運(yùn)景 指導(dǎo)教師職稱 副教授 完 成 時(shí) 間 2017 年 3 月 5 北華航天工業(yè)學(xué)院教務(wù)處制 譯文標(biāo)題 淺談汽車變速器 原文標(biāo)題 Discussion on automobile transmission 作 者 Helmut Kohl 譯 名 赫爾穆特·科爾 國(guó) 籍 德國(guó) 原文出處 德國(guó)法蘭克福匯報(bào) Transmission to change the engine to the driving wheel torque and speed, the purpose is in various driving conditions, different vehicle traction and speed, while the engine in the most favorable conditions within the scope of. The transmission consists of a variable speed transmission mechanism and a control mechanism. In China, the manual transmission is still the mainstream of the vehicle transmission. Sales of domestic and foreign automobile manufacturing data and display, the car ride comfort more and more attention. In the European market, the original manual transmission market, has been occupied by automatic transmission. In Britain, for example, automatic transmissions now account for 15% of the total. 5 years ago, the figure was $13.5%. It is estimated that by 2012, only 6% of the cars sold in the North American market will be manual. In the European transmission market in 2013, a manual automatic transmission will account for about 20%. In the China market, automatic transmission share is also increasing rapidly, predictably, the cars with automatic transmission is the leading products in the future market, and grasp the development of automatic transmission manufacturing technology is to catch up with the world trend in the direction of transmission manufacturing. The priority of the development of manual and automatic transmission has a technical continuity, for our country has a greater advantage. In the past ten years, the transmission industry in our country has attached great importance to the development of new products, both from the input of capital and the input of manpower and material resources. Ten years ago, we developed the most transmission products have a common characteristic, is the new product development process is not complete, but with the rapid development of these years in China, China's transmission product design and development process also gradually with foreign standards. The design and development process of a complete transmission new product usually includes: L. potential customer information collection. 2 transmission market survey, determine the direction of development. 3 develop technical solutions (identify key customer needs, determine the layout, refine customer needs, set development goals, etc.). 4 feasibility analysis. 5 conceptual design (Ratio selection, road load spectrum determination, the establishment of analytical models, Package and static dynamic gap analysis, etc.). With the development and application of CAD technology, a lot of researches and experiments have been carried out in many countries and departments. In the United States, Japan and Europe developed countries, the use of CAD technology to solve many tedious design and analysis calculations. The integrated system based on the graphics system, the database as the core, the tool system as the support, and the analysis and calculation as the application is formed. CAD technology in the United States has been in a leading position, its main goal is to establish a sound CAD/CAM integrated system. The earliest application of the CAD system in the automotive industry. General Motors Corporation, Ford and other companies have been widely used CAD technology. They will structure, strength and stiffness calculation, 3D solid modeling is applied in automobile design and development, CAD, CAPP, CAM, CAE integration, improve production efficiency, ensure product quality, improve the response speed of the market, thereby greatly improving their competitiveness, bring huge economic benefits for them. They are mainly used in CAD software PRO/E, UG, CATIA, IGES, etc. The automobile transmission is to solve the contradiction between the rotational speed and torque of the engine output and the speed and torque required by the vehicle. Vehicle performance is not only dependent on the engine, but also to a large extent depends on the transmission and the transmission and engine matching. At present, the application of automatic transmission technology, mainly in the following three forms: hydraulic automatic transmission; electronic controlled mechanical automatic transmission. Among them, the hydraulic automatic transmission and mechanical CVT, the same as the automatic transmission shift control, rather than cvt. Hydraulic automatic transmission.The basic structure of the hydraulic automatic transmission is composed of a hydraulic torque converter and an auxiliary transmission device of power shifting. Hydraulic torque converter installed in the engine and transmission between the hydraulic oil as the working medium, from the transmission torque, torque, speed and clutch role. Torque converter can automatically change the torque ratio and transmission ratio in a certain range, so as to adapt to the change of driving resistance. However, due to the torque converter torque coefficient is small, can not fully meet the requirements of the use of the car, so it must be used in combination with the gear transmission, expanding the range of transmission ratio. At present, most of the hydraulic automatic transmission uses planetary gear system as the auxiliary transmission. Planetary gear system is mainly composed of planetary gear mechanism and actuator. It can be seen that the hydraulic automatic transmission is actually able to realize the local stepless speed change of the transmission. Hydraulic automatic transmission is the most widely used automatic transmission. The adoption of this type of automatic transmission eliminates the complex operation of the manual transmission, so that the car becomes labor-saving. At the same time, the electronic control also makes the automatic switching process soft, smooth, so the car has a good ride comfort and safety, superior power and convenient maneuverability. But this kind of transmission efficiency is low, the structure is complex, the cost is also high. Electronically controlled mechanical automatic transmission Electronic control automatic transmission is based on the traditional fixed shaft transmission and dry clutch. The vehicle starting and shifting of the automatic control in the electronic control unit (ECU) as the core, through the hydraulic or pneumatic actuators to control the clutch separation and joint, shift operation and adjusting the engine of the solar term door. ECU according to the running state of the vehicle (engine speed, transmission input shaft speed, speed), the intention of the driver (throttle, brake pedal travel) and pavement condition (slope and curve) and other factors, according to the preset by the driving simulation of skilled driver (shift of the clutch engagement law), with the help of the corresponding actuator (engine throttle control actuator, clutch actuator, gearshift actuator), coordinated action on the engine, clutch and transmission of automatic control. AMT not only has the advantages of automatic transmission, but also retains the advantages of high efficiency, low cost, simple structure and easy manufacture. It combines the two advantages of high-tech products of electromechanical integration is very suitable for our country. It is the transformation of the mechanical transmission is the production of the original assembly retains most parts, only change the manual shift lever operating system, production of succession, the transformation of the investment costs less, is easy to be accepted by the manufacturers. Its disadvantage is non power shift, which can be obtained by the electronic control software to make up for. In several kinds of automatic transmission, the performance price ratio of AMT is the highest. In the middle and low grade cars, city buses, military vehicles, trucks and other aspects of the broad prospects for application. 變速器用來(lái)改變發(fā)動(dòng)機(jī)傳到驅(qū)輪上的轉(zhuǎn)矩和轉(zhuǎn)速，目的是在各種行駛工況下，使汽車獲得不同的牽引力和速度，同時(shí)使發(fā)動(dòng)機(jī)在最有利的工況范圍內(nèi)工作。變速器由變速傳動(dòng)機(jī)構(gòu)和操縱機(jī)構(gòu)組成。在中國(guó)，手動(dòng)變速器仍然是車用變速器的主流。國(guó)內(nèi)外的汽車制造與銷售數(shù)據(jù)顯示，人們對(duì)汽車駕乘的舒適性越來(lái)越重視。在歐洲市場(chǎng)，原本是手動(dòng)變速器的市場(chǎng)，不斷被自動(dòng)變速器占領(lǐng)。如在英國(guó).現(xiàn)在裝配自動(dòng)變速器的汽車占汽車總量的15%。而5年前，這個(gè)數(shù)字是13.5%。預(yù)計(jì)到2012年，北美市場(chǎng)出售的汽車中將只有6%是手動(dòng)擋；2013年歐洲變速器市場(chǎng)上，配備手動(dòng)自動(dòng)一體的變速器將占20%。而在中國(guó)市場(chǎng)上，自動(dòng)變速器的份額也在迅速增加，可以預(yù)見(jiàn)，帶有自動(dòng)變速器的汽車是未來(lái)市場(chǎng)的主導(dǎo)產(chǎn)品，發(fā)展和掌握自動(dòng)變速器制造技術(shù)是追趕世界變速器制造潮流的方向。而優(yōu)先開(kāi)發(fā)手動(dòng)自動(dòng)一體變速器具有技術(shù)上的延續(xù)性，對(duì)我國(guó)來(lái)說(shuō)具有更大的優(yōu)勢(shì)。 近十年以來(lái)，變速器產(chǎn)業(yè)在新產(chǎn)品開(kāi)發(fā)方面特別重視，無(wú)論是從資金的投入，還是人力物力的投入，都是空前巨大的。十幾年前，我們開(kāi)發(fā)的大部分變速器產(chǎn)品都有一個(gè)共同的特點(diǎn)，就是這些新產(chǎn)品的開(kāi)發(fā)流程是不完整的，而隨著我國(guó)這些年的高速發(fā)展，我國(guó)變速器產(chǎn)品的設(shè)計(jì)開(kāi)發(fā)流程也逐漸與國(guó)外接軌。 一個(gè)完整的變速器新產(chǎn)品的設(shè)計(jì)開(kāi)發(fā)流程通常包括： l.潛在顧客的信息收集。2.變速器市場(chǎng)調(diào)查、確定開(kāi)發(fā)方向。3.制定技術(shù)方案（識(shí)別顧客關(guān)鍵需求、確定布置方案、細(xì)化顧客需求、設(shè)定開(kāi)發(fā)目標(biāo)等）。4.可行性分析。5 概念設(shè)計(jì)（Ratio的選擇、道路載荷譜的確定、建立分析模型、Package及靜態(tài)動(dòng)態(tài)間隙分析等優(yōu)質(zhì)產(chǎn)品。 隨著CAD技術(shù)的發(fā)展和應(yīng)用，許多國(guó)家和部門(mén)都對(duì)其進(jìn)行了大量的研究和試驗(yàn)，隨之開(kāi)發(fā)并形成一些成套硬件和軟件系統(tǒng)。在美國(guó)、日本及歐洲發(fā)達(dá)國(guó)家中，利用CAD技術(shù)解決眾多繁瑣的設(shè)計(jì)和分析計(jì)算。形成了以圖形系統(tǒng)為基礎(chǔ)、以數(shù) 據(jù)庫(kù)為核心、以工具系統(tǒng)為支撐和以分析計(jì)算為應(yīng)用的集成化系統(tǒng)。 美國(guó)的CAD技術(shù)一直處于領(lǐng)先地位，其主要目標(biāo)就是建立完善的CAD/CAM集成系統(tǒng)。美國(guó)汽車工業(yè)最早應(yīng)用了CAD系統(tǒng)。美國(guó)通用汽車公司、福特汽車公司等都已廣泛應(yīng)用CAD技術(shù)。他們將結(jié)構(gòu)、強(qiáng)度、剛度等計(jì)算、三維實(shí)體造型應(yīng)用于汽車的設(shè)計(jì)開(kāi)發(fā)中，將CAD、CAPP、CAM、CAE集成，使生產(chǎn)效率提高，產(chǎn)品質(zhì)量得到保證，市場(chǎng)響應(yīng)速度提高，從而大大地提高了他們的競(jìng)爭(zhēng)力，為他們帶來(lái)了巨大的經(jīng)濟(jì)效益。他們應(yīng)用的CAD軟件主要有PRO/E、UG、CATIA、IGES等。 汽車變速器是為解決發(fā)動(dòng)機(jī)輸出的轉(zhuǎn)速和轉(zhuǎn)矩與車輛驅(qū)動(dòng)所需的轉(zhuǎn)速和轉(zhuǎn)矩間的矛盾而設(shè)立的。車輛行駛性能的好壞，不僅取決于發(fā)動(dòng)機(jī)，而且在很大程度上還依賴于變速器以及變速器與發(fā)動(dòng)機(jī)的匹配。 目前自動(dòng)變速器技術(shù)的應(yīng)用，主要有以下三種形式：液力自動(dòng)變速器;電控機(jī)械式自動(dòng)變速器，簡(jiǎn)稱;機(jī)械無(wú)級(jí)變速器。其中，液力自動(dòng)變速器和機(jī)械無(wú)級(jí)變速器一樣，是有級(jí)變速器的自動(dòng)換檔控制，而非無(wú)級(jí)變速器。 液力自動(dòng)變速器 液力自動(dòng)變速器的基本結(jié)構(gòu)是由液力變矩器與動(dòng)力換檔的輔助變速裝置組成。液力變矩器安裝在發(fā)動(dòng)機(jī)和變速器之間，以液壓油為工作介質(zhì)，起傳遞轉(zhuǎn)矩、變矩、變速及離合的作用。液力變矩器可在一定范圍內(nèi)自動(dòng)無(wú)級(jí)地改變轉(zhuǎn)矩比和傳動(dòng)比，以適應(yīng)行駛阻力的變化。但是由于液力變矩器變矩系數(shù)小，不能完全滿足汽車使用的要求，所以，它必須與齒輪變速器組合使用，擴(kuò)大傳動(dòng)比的變化范圍。目前，絕大多數(shù)液力自動(dòng)變速器都采用行星齒輪系統(tǒng)作為輔助變速器。行星齒輪系統(tǒng)主要由行星齒輪機(jī)構(gòu)和執(zhí)行機(jī)構(gòu)組成，通過(guò)改變動(dòng)力傳遞路線得到不同的傳動(dòng)比。由此可見(jiàn)，液力自動(dòng)變速器實(shí)際上是能實(shí)現(xiàn)局部無(wú)級(jí)變速的有級(jí)變速器。液力自動(dòng)變速器是目前使用最多的自動(dòng)變速器。采用此種類型的自動(dòng)變速器，免除了手動(dòng)變速器繁雜的操作，使開(kāi)車變得省力。同時(shí)，電子控制也使自動(dòng)切換過(guò)程柔和、平順，因此汽車具有良好的乘坐舒適性和安全性、優(yōu)越的動(dòng)力性和方便的操縱性。但這種變速器效率低，結(jié)構(gòu)復(fù)雜，成本也較高。 電控機(jī)械式自動(dòng)變速器 電控機(jī)械式自動(dòng)變速器是在傳統(tǒng)固定軸式變速器和干式離合器的基礎(chǔ)上，應(yīng)用電子技術(shù)和自動(dòng)變速理論來(lái)實(shí)現(xiàn)機(jī)電一體化協(xié)調(diào)控制的。車輛起步、換檔的自動(dòng)操縱是以電控單元（ECU）為核心，通過(guò)液壓或氣壓執(zhí)行機(jī)構(gòu)來(lái)控制離合器的分離與接合、選換檔操作以及發(fā)動(dòng)機(jī)節(jié)氣門(mén)的調(diào)節(jié)的。ECU根據(jù)車輛的運(yùn)行狀況（發(fā)動(dòng)機(jī)轉(zhuǎn)速、變速器輸入軸轉(zhuǎn)速、車速）、駕駛員意圖（油門(mén)開(kāi)度、制動(dòng)踏板行程）和道路路面狀況（坡道、彎道）等因素，按預(yù)先設(shè)定的由模擬熟練駕駛員的駕駛規(guī)律（換檔規(guī)律、離合器接合規(guī)律），借助于相應(yīng)的執(zhí)行機(jī)構(gòu)（發(fā)動(dòng)機(jī)油門(mén)控制執(zhí)行機(jī)構(gòu)、離合器執(zhí)行機(jī)構(gòu)、變速器換檔執(zhí)行機(jī)構(gòu)），對(duì)發(fā)動(dòng)機(jī)、離合器、變速器的協(xié)調(diào)動(dòng)作進(jìn)行自動(dòng)操縱。 AMT既具有液力自動(dòng)變速器自動(dòng)變速的優(yōu)點(diǎn)，又保留了原手動(dòng)變速器齒輪傳動(dòng)的效率高、成本低、結(jié)構(gòu)簡(jiǎn)單、易制造的長(zhǎng)處。它揉合了二者優(yōu)點(diǎn)，是非常適合我國(guó)國(guó)情的機(jī)電一體化高新技術(shù)產(chǎn)品。它是在現(xiàn)生產(chǎn)的機(jī)械變速器上進(jìn)行改造的，保留了絕大部分原總成部件，只改變其中手動(dòng)操作系統(tǒng)的換檔桿部分，生產(chǎn)繼承性好，改造的投入費(fèi)用少，非常容易被生產(chǎn)廠家接受。它的缺點(diǎn)是非動(dòng)力換檔，這可以通過(guò)電控軟件方面來(lái)得到一定彌補(bǔ)。 在幾種自動(dòng)變速器中，AMT的性能價(jià)格比最高。在中低檔轎車、城市客車、軍用車輛、載貨車等方面應(yīng)用前景較廣闊。 指 導(dǎo) 教 師 評(píng) 語(yǔ) 外文翻譯成績(jī)： 指導(dǎo)教師簽字： 年 月 日 注：1. 指導(dǎo)教師對(duì)譯文進(jìn)行評(píng)閱時(shí)應(yīng)注意以下幾個(gè)方面：①翻譯的外文文獻(xiàn)與畢業(yè)設(shè)計(jì)（論文）的主題是否高度相關(guān)，并作為外文參考文獻(xiàn)列入畢業(yè)設(shè)計(jì)（論文）的參考文獻(xiàn)；②翻譯的外文文獻(xiàn)字?jǐn)?shù)是否達(dá)到規(guī)定數(shù)量（3 000字以上）；③譯文語(yǔ)言是否準(zhǔn)確、通順、具有參考價(jià)值。 2. 外文原文應(yīng)以附件的方式置于譯文之后。 共 5 頁(yè) 第 7 頁(yè) 密 級(jí) 分類號(hào) 編 號(hào) 成 績(jī) 本科生畢業(yè)設(shè)計(jì) (論文) 外 文 翻 譯 原 文 標(biāo) 題 自動(dòng)變速器 譯 文 標(biāo) 題 AUTOMATIC TRANSMISSION 作者所在系別 機(jī)電工程學(xué)院 作者所在專業(yè) 車輛工程 作者所在班級(jí) B13142 作 者 姓 名 高家寶 作 者 學(xué) 號(hào) 201322393 指導(dǎo)教師姓名 焦運(yùn)景 指導(dǎo)教師職稱 副高 完 成 時(shí) 間 2017 年 3 月 譯文標(biāo)題 自動(dòng)變速器 原文標(biāo)題 AUTOMATIC TRANSMISSION 作 者 譯 名 國(guó) 籍 原文出處 The modern automatic transmission is by far , the most complicated mechanical component in today’s automobile . It is a type of transmission that sifts itself . A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine . There are two basic types of automatic transmission based on whether the vehicle is rear wheel drive or front wheel drive . On a rear wheel drive car , the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position . A drive shaft connects the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels . Power flow on this system is simple and straight forward going from the engine , through the torque converter , then trough the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear transmission . On a front wheel drive car , the transmission is usually combined with the final drive to form what is called a transaxle . The engine on a front wheel drive car is usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car . Front axles are connected directly to the transaxle and provide power to front wheels . In this example , power floes from the engine , through the torque converter to a larger chain that sends the power through a 180 degree turn to the transmission that is along side the engine . From there , the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles . There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular . A much less popular rear and is connected by a drive shaft to the torque converter which is still mounted on the engine . This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling . Another rear drive system mounts everything , the engine , transmission and final drive in the rear . This rear engine arrangement is popular on the Porsche. The modern automatic transmission consists of many components and systems that designed to work together in a symphony of planetary gear sets , the hydraulic system, seals and gaskets , the torque converter , the governor and the modulator or throttle cable and computer controls that has evolved over the years into what many mechanical inclined individuals consider to be an art from . Here try to used simple , generic explanation where possible to describe these systems . 1. Planetary gear sets Automatic transmission contain many gears in various combinations . In a manual transmission , gears slide along shafts as you move the shift lever from one position to another , engaging various sizes gears as required in order to provide the correct gear ratio . In an automatic transmission , how ever , the gears are never physically moved and are always engaged to the same gears . This is accomplished through the use of planetary gear sets . The basic planetary gear set consists of a sun gear , a ring and two or more planet gears , all remaining in constant mesh . The planet gears are connected to each other through a common carrier which allows the gears to spin on shafts called “pinions” which are attached to the carrier . One example of a way that this system can be used is by connecting the ring gear to the input shaft coming from the engine , connecting the planet carrier to the output shaft , and locking the sun gear so that it can’t move . In this scenario , when we turn the ring gear , the planets will “walk” along the sun gear ( which is held stationary ) causing the planet carrier to turn the output shaft in the same direction as the input shaft but at a slower speed causing gear reduction ( similar to a car in first gear ) . If we unlock the sun gear and lock any two elements together , this will cause all three elements to turn at the same speed so that to output shaft will turn at the same rate of speed as the input shaft . This is like a car that is third or high gear . Another way we can use a planetary gear set is by locking the planet carrier from moving , then applying power to the ring gear which will cause the sun gear to turn in opposite direction giving us reverse gear . The illustration in Figure shows how the simple system described above would look in an actual transmission . The input shaft is connected to the ring gear , the output shaft is connected to the planet carrier which is also connected to a “Multi-disk” clutch pack . The sun gear is connected to drum which is also connected to the other half of the clutch pack . Surrounding the outside of the drum is a band that can be tightened around the drum when required to prevent the drum with the attached sun gear from turning . The clutch pack is used , in this instance , to lock the planet carrier with the sun gear forcing both to turn at the same speed . If both the clutch pack and the band were released , the system would be in neutral . Turning the input shaft would turn the planet gears against the sun gear , but since noting is holding the sun gear , it will just spin free and have no effect on the output shaft . To place the unit in first gear , the band is applied to hold the sun gear from moving . To shift from first to high gear , the band is released and the clutch is applied causing the output shaft to turn at the same speed as the input shaft . Many more combinations are possible using two or more planetary sets connected in various way to provide the different forward speeds and reverse that are found in modern automatic transmission . 2. Clutch pack A clutch pack consists of alternating disks that fit inside a clutch drum . Half of the disks are steel and have splines that fit into groves on the inside of the drum . The other half have a friction material bonded to their surface and have splines on the inside edge that fit groves on the outer surface of the adjoining hub . There is a piston inside the drum that is activated by oil pressure at the appropriate time to squeeze the clutch pack together so that the two components become locked and turn as one . 3. Torque Converter On automatic transmission , the torque converter takes the place of the clutch found on standard shift vehicles . It is there to allow the engine to continue running when the vehicle comes to a stop . The principle behind a torque converter is like taking a fan that is plugged into the wall and blowing air into another fan which is unplugged . If you grab the blade on the unplugged fan , you are able to hold it from turning but as soon as you let go , it will begin to speed up until it comes close to speed of the powered fan . The difference with a torque converter is that instead of using air it used oil or transmission fluid , to be more precise . A torque converter is a lager doughnut shaped device that is mounted between the engine and the transmission . It consists of three internal elements that work together to transmit power to the transmission . The three elements of the torque converter are the pump , the Turbine , and the Stator . The pump is mounted directly to the torque housing which in turn is bolted directly to the engine’s crankshaft and turns at engine speed . The turbine is inside the housing and is connected directly to the input shaft of the transmission providing power to move the vehicle . The stator is mounted to a one-way clutch so that it can spin freely in one direction but not in the other . Each of the three elements has fins mounted in them to precisely direct the flow of oil through the converter . With the engine running , transmission fluid is pulled into the pump section and is pushed outward by centrifugal force until it reaches the turbine section which stars it running . The fluid continues in a circular motion back towards the center of the turbine where it enters the stator . If the turbine is moving considerably slower than the pump , the fluid will make contact with the front of the stator fins which push the stator into the one way clutch and prevent it from turning . With the stator stopped , the fluid is directed by the stator fins to re-enter the pump at a “help” angle providing a torque increase . As the speed of the turbine catches up with the pump , the fluid starts hitting the stator blades on the back-side causing the stator to turn in the same direction as the pump and turbine . As the speed increase , all three elements begin to turn at approximately the same speed . Sine the ‘80s , in order to improve fuel economy , torque converters have been equipped with a lockup clutch which locks the turbine to the pump as the vehicle reaches approximately 40-50 mph . This lockup is controlled by computer and usually won’t engage unless the transmission is in 3rd or 4th gear . 4. Hydraulic System The hydraulic system is a complex maze of passage and tubes that sends that sends transmission fluid and under pressure to all parts of the transmission and torque converter and . Transmission fluid serves a number of purpose including : shift control ,general lubrication and transmission cooling . Unlike the engine ,which uses oil primary for lubrication ,every aspect of a transmission ‘s function is dependant on a constant supply of fluid is send pressure . In order to keep the transmission at normal operating temperature , a portion of the fluid is send to through one of two steel tubes to a special chamber that is submerged in anti-freeze in the radiator . Fluid passing through this chamber is cooled and then returned to the transmission through the other steel tube . A typical transmission has an avenge of ten quarts of fluid between the transmission , torque converter , and cooler tank , In fact , most of the components of a transmission are constantly submerged in fluid including the clutch packs and bands . The friction surfaces on these parts are designed to operate properly only when they are submerged in oil . 5. Oil Pump The transmission oil pump ( not to confused with the pump element inside the torque converter ) is responsible for producing all the oil pressure that is required in the transmission . The oil pump is mounted to front of the transmission case and is directly connected to a flange on the engine crankshaft , the pump will produce pressure whenever the engine is running as there is a sufficient amount of transmission fluid available . The oil enters the pump through a filter that is located at bottom of the transmission oil pan and travels up a pickup tube directly to the oil pump . The oil is then sent , under pressure to the pressure regulator , the valve body and the rest of the components , as required . 6. Valve Body The valve body is the control center of the automatic transmission . It contains a maze of channels and passages that direct hydraulic fluid to the numerous valves which when activate the appropriate clutch pack of band servo to smoothly shift to the appropriate gear for each driving situation . Each of the many valves in the valve body has a specific purpose and is named for that function . For example the shift valve activates the 2nd gear up-shift or the shift timing valve which determines when a downshift should occur . The most important valve and the one that you have direct control over is the manual valve. The manual valve is directly connected to the gear shift handle and covers and uncovers various passages depending on what position the gear shift is paced in . When you place the gear shift in Drive , for instance , the manual valve directs fluid to the clutch pack ( s ) that activates 1st gear . It also sets up to monitor vehicle speed and throttle position so that it can determine the optimal time and the force for the 1-2 shift . On computer controlled transmission , you will also have electrical solenoids that are mounted in the valve body to direct fluid to the appropriate clutch packs or bands under computer control to more precisely control shift points . 7. Computer Controls The computer uses sensors on the engine and transmission to detect such things as throttle position , vehicle speed , engine speed , engine load , stop light switch position , etc . to control exact shift points as well as how soft or firm the shift should be . Some computerized transmission even learn your driving style and constantly adapt to it so that every shift is timed precisely when you would need it . Because of computer controls , sports models are coming out with the ability to take manual control of the transmission as through it were a stick shift lever through a special gate , then tapping it in one direction or the other in order to up-shift at will . The computer monitors this activity to make sure that the driver dose not select a gear that could over speed the engine and damage it . Another advantage to these “ smart” transmission is that they have a self diagnostic mode which can detect a problem early on and warn you with an indicator light on the dash . A technician can then plug test equipment in and retrieve a list of trouble codes that will help pinpoint where the problem is . 指 導(dǎo) 教 師 評(píng) 語(yǔ) 外文翻譯成績(jī)： 指導(dǎo)教師簽字： 年 月 日 注：1. 指導(dǎo)教師對(duì)譯文進(jìn)行評(píng)閱時(shí)應(yīng)注意以下幾個(gè)方面：①翻譯的外文文獻(xiàn)與畢業(yè)設(shè)計(jì)（論文）的主題是否高度相關(guān)，并作為外文參考文獻(xiàn)列入畢業(yè)設(shè)計(jì)（論文）的參考文獻(xiàn)；②翻譯的外文文獻(xiàn)字?jǐn)?shù)是否達(dá)到規(guī)定數(shù)量（3 000字以上）；③譯文語(yǔ)言是否準(zhǔn)確、通順、具有參考價(jià)值。 2. 外文原文應(yīng)以附件的方式置于譯文之后。 共 6頁(yè) 第 10 頁(yè)