【正文】 轉(zhuǎn)動并在閥桿上推下去，使得閥移到低處，也就是說閥被打開了。凸輪軸通過齒輪或鏈條齒和齒條受到機軸的驅(qū)動。活塞的這個移動引起了氣缸內(nèi)的局部的真空，同時空氣通過進氣閥推進氣缸，以填補該真空。 當(dāng)活塞在進口端移到下止點時，進氣閥關(guān)閉。直到活塞被推到上止點時，氣體被壓縮成原來的七分之一或八分之一?；鸹ㄈ举|(zhì)上是兩個粗鋼絲電極。此時，活塞頂端向下的壓力達到兩噸。這時，活塞又一次被返回，它推動氣缸內(nèi)被燃燒過的氣體。發(fā)動機運行時，這四個行程持續(xù)地重復(fù)著。在裝配有手工傳動的汽車系統(tǒng)中，這可以通過一個機械離合器獲得成功。壓力盤通過彈力壓住驅(qū)動盤，這樣扭矩由于發(fā)動機和傳送的輸入軸之間的摩擦力而被傳動。 除了壓力盤和驅(qū)動盤，離合器還包含有一個外殼、釋放桿、釋放軛、壓力彈簧和一個控制連接。這樣的裝置允許壓力盤接近或離開外殼，并一直隨著調(diào)速盤而轉(zhuǎn)動。 液壓制動離合器分離裝置由一個踏板、分離彈簧、主氣缸、氣力調(diào)壓器、管道、軟管、分離叉的桿組成。機架供應(yīng)氣力的、水壓的、伺服的活塞。一個德國的汽車制造者設(shè)計了一個自動的離合器系統(tǒng)叫做Hydrak，它由一個液力飛輪連接著一個干燥的轉(zhuǎn)盤。這激勵了一個用以分離離合器轉(zhuǎn)盤的調(diào)壓器系統(tǒng)。叫做半離心式離合器，壓盤有六個圓柱滾輪，它在離心力的作用下向外運動，直至觸到外殼。對于水平路面，如果沒有變速器，汽車可以通過發(fā)動機的加速和離合器的連接而啟動。同樣需要一個速比以避免高速公路上過高的發(fā)動機轉(zhuǎn)速/每分鐘。為了配合這些變化的扭矩的需要，用到一個特殊的齒輪箱。如果在主動齒輪和從動齒輪之間引進中間齒輪，從動齒輪的轉(zhuǎn)動方向?qū)兓］斎胼S是剛鑄的，又主動齒輪和輪緣構(gòu)成整體。輸出端的另一端在變速器機身的滾動軸承中做旋轉(zhuǎn)運動。回轉(zhuǎn)齒輪（單個齒輪或兩個齒輪組）由機身上的孔確保在軸輪上轉(zhuǎn)動。有兩個滑動齒輪或同步嚙合套的叫做2范圍，三個齒輪的叫做3范圍。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