【正文】 譯文The basic mechanisms Of AutomobilesThe automobile industry is a fast developing industry. From the later 18th century when the first automobile was put on road, this industry has developed tremendously. Now there are thousands of factories all over the world manufacturing numerous types of automobiles. This industry employs crores of men and women directly and indirectly in allied industries. The automobile engines are also being used in engine powered machines for agriculture, construction and manufacturing processes. Various types of small engines are also being used in lawn movers, power saws, snow removers and similar equipment. The automobile industry is a developing and demanding industry which does not find its end or saturation point. There is a great demand for varied types of automotive products, vehicles and engines. There is also a great demand for trained and experienced persons in this industry for diagnosing motor vehicle troubles, repairing and replacing engines ponents, transmissions, propeller shafts, differentials, axles, steering system ponents,brake system ponents, suspension ponents, airconditioners, heaters, body and glass work. The automobile consists of five basic mechanisms, or ponents. These are :(1) The engine, which is the source of power, including the fuel, lubricating, cooling, and electric systems(2) The frame, which supports the engine, wheels, steering and brake systems, and body(3) The power train, which carries the power from the engine(through the clutch,transmission, drive shaft, differential, and axles)to the car wheels (4) The car body (5) carbody accessories, including heater ,lights, windshield wipers, and so forthThe engine is the source of power that makes the car move. It is usually called an internal bustion engine because gasoline is burned inside the engine cylinders, or bustion chambers. This is in contrast to externalbustion engines(such as steam engines),where the bustion takes place outside the engine. The burning of gasoline in the engine cylinders produces the power. The power is then carried from the engine through the power train to the car wheels so that the wheels turn and the car moves. The fuel system plays a vital part in the power producing process since it supplies the gasoline to the engine cylinders. In each engine cylinder, a mixture of gasoline vapor and air enters the cylinder, the piston pushes up into the cylinder to press the mixture, and then an electric spark ignites the pressed mixture so that the piston is forced downward. Of course, in the engine the piston is not blown pletely out of the cylinder, the piston simply moves up and down in the cylinderup to press as the mixture burns. The piston straightline motion must be changed to rotary motion before it can be used to make the car wheels rotate. A connecting rod and a crank on the engine crankshaft make this change. The engine valves get the burned gasoline vapor out of the engine cylinder andbringing fresh changes of gasoline vapor and air into the cylinder. There are two openings ,or ports, in the enclosed end of the cylinder ,each containing a valve. The valve are accurately machined plugs on long stems. When they are closed, or seated (that is, moved up into the ports), the ports are sealed off and gas cannot pass through the ports. When the valve is open, gas can pass through the port. The valves are opened by cams on the engine camshaft. The cam has a high point,or lobe?；剞D(zhuǎn)齒輪（單個(gè)齒輪或兩個(gè)齒輪組）由機(jī)身上的孔確保在軸輪上轉(zhuǎn)動(dòng)。輸入軸是剛鑄的，又主動(dòng)齒輪和輪緣構(gòu)成整體。為了配合這些變化的扭矩的需要，用到一個(gè)特殊的齒輪箱。對(duì)于水平路面，如果沒(méi)有變速器，汽車可以通過(guò)發(fā)動(dòng)機(jī)的加速和離合器的連接而啟動(dòng)。這激勵(lì)了一個(gè)用以分離離合器轉(zhuǎn)盤(pán)的調(diào)壓器系統(tǒng)。機(jī)架供應(yīng)氣力的、水壓的、伺服的活塞。這樣的裝置允許壓力盤(pán)接近或離開(kāi)外殼，并一直隨著調(diào)速盤(pán)而轉(zhuǎn)動(dòng)。壓力盤(pán)通過(guò)彈力壓住驅(qū)動(dòng)盤(pán)，這樣扭矩由于發(fā)動(dòng)機(jī)和傳送的輸入軸之間的摩擦力而被傳動(dòng)。發(fā)動(dòng)機(jī)運(yùn)行時(shí)，這四個(gè)行程持續(xù)地重復(fù)著。此時(shí)，活塞頂端向下的壓力達(dá)到兩噸。直到活塞被推到上止點(diǎn)時(shí)，氣體被壓縮成原來(lái)的七分之一或八分之一。活塞的這個(gè)移動(dòng)引起了氣缸內(nèi)的局部的真空，同時(shí)空氣通過(guò)進(jìn)氣閥推進(jìn)氣缸，以填補(bǔ)該真空。搖桿臂在它的支撐體上轉(zhuǎn)動(dòng)并在閥桿上推下去，使得閥移到低處，也就是說(shuō)閥被打開(kāi)了。在汽車車輪能夠轉(zhuǎn)動(dòng)之前，活塞的線性運(yùn)動(dòng)必須轉(zhuǎn)變成旋轉(zhuǎn)運(yùn)動(dòng)。 發(fā)動(dòng)機(jī)是使得汽車運(yùn)行的動(dòng)力源泉。汽車、運(yùn)輸工具、發(fā)動(dòng)機(jī)有著巨大的需求量。汽車的基本機(jī)械機(jī)構(gòu)汽車工業(yè)是一種迅速發(fā)展的工業(yè)。這一行業(yè)同樣需要受過(guò)鍛煉的、有經(jīng)驗(yàn)的精英，來(lái)診斷這些機(jī)動(dòng)車輛的故障、修理和更新機(jī)動(dòng)車的零件、變速器、推動(dòng)軸、差分器、車軸、操縱系統(tǒng)、剎車系統(tǒng)、暫停部件、空調(diào)裝置、發(fā)熱器、機(jī)身以及玻璃制造等。它通常叫做一個(gè)內(nèi)置的燃燒發(fā)動(dòng)機(jī)，因?yàn)槠褪窃诎l(fā)動(dòng)機(jī)氣缸或燃燒腔內(nèi)被燃燒的。發(fā)動(dòng)機(jī)機(jī)軸上的連桿和曲柄實(shí)現(xiàn)了這一轉(zhuǎn)變。當(dāng)凸輪轉(zhuǎn)動(dòng)得足夠使突出部分移出挺桿之下時(shí)，承重的閥門彈簧將閥門退回到自己的位置。當(dāng)空氣向氣缸移動(dòng)時(shí)，它必須經(jīng)過(guò)氣化器。這就類似一加侖的空氣被壓所成一品托。這個(gè)巨大的推力使得活塞向下，同時(shí)巨大的沖力通過(guò)連桿和曲柄傳送到機(jī)軸。 離合器是一種摩擦裝置，它用于從從動(dòng)機(jī)構(gòu)中聯(lián)合和拆分驅(qū)動(dòng)力。 汽車一般裝有干式彈力離合器。沿壓盤(pán)和離合器蓋之間的圓周均