【正文】 ront engine, transmission and differential usually installed in together. 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 lots of other decorates, engine front front drive, engine horizontal layout, furnish a thansfer can realize the fourwheel 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. Modern automatic transmission includes many ponents and systems work together, a planetary gear set, hydraulic pressure system, seal and gasket, torque converter, regulators, throttle barrows, puter control these are other years mechanical evolution.1）Computer Controls Because of puter controls , sports models are ing 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 upshift at will . The puter monitors this activity to make sure that the driver dose not select a gear that could over speed the engine and damage it.2）Oneway Clutch A oneway clutch ( also known as a “sprig” clutch ) is a device that will allow a ponent such as ring gear to turn freely in one direction but not in the other . This effect is just like that bicycle , where the pedals will turn the wheel when pedaling forward , but will spin free when pedaling backward . 3）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 23 shift valve activates the 2nd gear upshift or the 32 shift timing valve which determines when a downshift should occur.4）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 ponents , as required . 5）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 es 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 es 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 . 6）Planetary gear sets Automatic transmission contain many gears in various binations . 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 , however , the gears are never physically moved and are always engaged to the same gears . This is acplished through the use of planetary gear sets . 自動(dòng)變速器對(duì)于現(xiàn)代的汽車(chē)，自動(dòng)變速器是一個(gè)復(fù)雜的組件，這種傳遞動(dòng)力的方式，是液力耦合變矩器充當(dāng)離合器來(lái)連接發(fā)動(dòng)機(jī)和變速器。 有兩種基本的自動(dòng)變速器基于車(chē)輛是否后輪驅(qū)動(dòng)或前輪驅(qū)動(dòng)裝置。對(duì)發(fā)動(dòng)機(jī)前置后驅(qū)的汽車(chē)，變速器通常安裝在發(fā)動(dòng)機(jī)后底盤(pán)中心與油門(mén)配合。變速器輸出軸連接到后橋，把發(fā)動(dòng)機(jī)的動(dòng)力傳遞到后輪，動(dòng)力傳輸系統(tǒng)是直線的，從發(fā)動(dòng)機(jī)，通過(guò)液力變矩器、變速器、傳動(dòng)軸、最后直接到達(dá)車(chē)輪。 在一個(gè)前輪驅(qū)動(dòng)的汽車(chē)，傳遞都是由變速器和差速器接連在一起的。對(duì)于前驅(qū)動(dòng)的汽車(chē)，變速器安裝在發(fā)動(dòng)機(jī)一側(cè)，前車(chē)軸直接連接到差速器上，把動(dòng)力傳遞給前輪。在這個(gè)布置中，動(dòng)力來(lái)自于發(fā)動(dòng)機(jī)，通過(guò)液力變矩器、變速器輸出的動(dòng)力通過(guò)了一個(gè)180度大轉(zhuǎn)彎，經(jīng)過(guò)變速器沿發(fā)動(dòng)機(jī)側(cè)邊通過(guò)傳動(dòng)軸輸出到前輪。 有許多其他的裝置包括前驅(qū)動(dòng)車(chē)輛如引擎安裝在一邊，而不是還有其他的系統(tǒng)驅(qū)動(dòng)所有四個(gè)車(chē)輪，但這里描述的這兩個(gè)系統(tǒng)是到目前為止最受歡迎的。但這種形式目前是最常用的：發(fā)動(dòng)機(jī)中置后驅(qū)動(dòng)，可以使重量均勻的分布在前、后輪之間，改善了操作性能；發(fā)動(dòng)機(jī)后置后驅(qū)動(dòng)，發(fā)動(dòng)機(jī)、變速器、驅(qū)動(dòng)輪都在后方，這種后置式的發(fā)動(dòng)機(jī)的安排，是最滿意的。 現(xiàn)代的自動(dòng)變速器包括了許多組件和系統(tǒng)的協(xié)同工作，有行星齒輪組、液壓系統(tǒng)、密封件和墊圈、變矩器、調(diào)節(jié)器、節(jié)氣門(mén)拉線、計(jì)算機(jī)控制這些都是多年來(lái)由機(jī)械式演變過(guò)來(lái)的。1）計(jì)算機(jī)控制由于計(jì)算機(jī)的控制，通過(guò)一個(gè)特殊的元素代替了手動(dòng)控制，在每一個(gè)工況都是安全的。計(jì)算機(jī)的控制，確保發(fā)動(dòng)機(jī)轉(zhuǎn)速不至于過(guò)高而使發(fā)動(dòng)機(jī)損壞2）單向離合器單向離合器是一種只可以使元件在一個(gè)方向轉(zhuǎn)動(dòng)，如把齒圈自由在一貫方向，而不能反向轉(zhuǎn)動(dòng)，這種作用就象是，自行車(chē)踏板轉(zhuǎn)動(dòng)時(shí)，可以帶動(dòng)車(chē)輪轉(zhuǎn)動(dòng)，當(dāng)車(chē)輪轉(zhuǎn)動(dòng)或向另一個(gè)方向轉(zhuǎn)動(dòng)是自由的3）閥體閥體是自動(dòng)變速器的控制中心。它包含一個(gè)迷宮壯的通道輸送液壓油，在每一個(gè)工況下控制離合器和其它伺服機(jī)構(gòu)，順利的控制齒輪傳動(dòng)情況。4）油泵油泵主要是負(fù)責(zé)提供油液傳輸過(guò)程中的壓力，油泵安裝在前面的泵輪上，并且以發(fā)動(dòng)機(jī)的曲軸相連，當(dāng)發(fā)動(dòng)機(jī)轉(zhuǎn)動(dòng)時(shí)，帶動(dòng)油泵運(yùn)轉(zhuǎn)，產(chǎn)生壓力，提供足夠的油。油進(jìn)入油泵時(shí)通過(guò)一個(gè)空氣濾清器，安裝在油底殼的底部。壓力調(diào)節(jié)器、調(diào)壓閥、壓力修正閥調(diào)節(jié)后送到各個(gè)管路。5）液力變矩器對(duì)于自動(dòng)變速器，液力變矩器取代離合器裝于車(chē)上。它的作用是：當(dāng)車(chē)停下來(lái)，發(fā)動(dòng)機(jī)還可以繼續(xù)運(yùn)轉(zhuǎn)。傳遞扭矩的原理，比如，把一個(gè)風(fēng)扇吹向另一個(gè)，另一個(gè)不用插電也能跟它一起轉(zhuǎn)動(dòng)，如果你壓住扇片，它就不會(huì)轉(zhuǎn)動(dòng)，但你一放手，它就開(kāi)始加速，直到速度接近動(dòng)力風(fēng)扇。它們兩者的差異就是：變矩器不是利用空氣，而是利用油液，以使他的傳遞更加準(zhǔn)確。6）行星齒輪組 自動(dòng)變速器車(chē)輪包含許多不同的組合，在一個(gè)變速箱內(nèi)，齒輪的滑動(dòng)沿軸線從一個(gè)位置到另一個(gè)位置，對(duì)各種大小齒輪的要求，有正確的傳動(dòng)比。在一個(gè)自動(dòng)變速箱，至始至終，不是齒輪的機(jī)械移動(dòng)來(lái)達(dá)到這一點(diǎn)的，通過(guò)行星齒輪組來(lái)完成。