第一篇：內(nèi)燃機(jī)專業(yè)英語(yǔ)教案

內(nèi)燃機(jī)專業(yè)英語(yǔ)自編講義部分：

一、教學(xué)內(nèi)容：

在該部分內(nèi)容中主要講述內(nèi)燃機(jī)、汽油發(fā)動(dòng)機(jī)、柴油發(fā)動(dòng)機(jī)等的相關(guān)知識(shí)。包括：1.Engine Classification and Overall Mechanics，發(fā)動(dòng)機(jī)的分類(lèi)和總體結(jié)構(gòu)；2.Four-stage-engine Operation，四行程發(fā)動(dòng)機(jī)工作過(guò)程；3.Two-stage-engine Operation，二行程發(fā)動(dòng)機(jī)工作過(guò)程；4.Diesel Engine Operating Features，柴油發(fā)動(dòng)機(jī)工作特點(diǎn)；5.Engine Cylinder Block Crankcase，發(fā)動(dòng)機(jī)氣缸體

曲軸箱；6.Piston Connecting Rod，活塞 連桿；7.Crankshaft Flywheel，曲軸 飛輪；8.Valves and Vales Train，氣門(mén)與氣門(mén)傳動(dòng)組；9.Engine Fuel System，發(fā)動(dòng)機(jī)燃油系統(tǒng)；10.Engine Lubricating System，發(fā)動(dòng)機(jī)潤(rùn)滑系統(tǒng)；11.Engine Cooling System，發(fā)動(dòng)機(jī)冷卻系統(tǒng)；12.Engine Ignition System，發(fā)動(dòng)機(jī)點(diǎn)火系統(tǒng)；13.Engine Starting System，發(fā)動(dòng)機(jī)起動(dòng)系統(tǒng)；14.Locomotives，機(jī)車(chē)；15.Diesel Traction，內(nèi)燃牽引。

二、教學(xué)時(shí)數(shù)：

共占用18學(xué)時(shí)。

1.Engine Classification and Overall Mechanics（1學(xué)時(shí)）發(fā)動(dòng)機(jī)的分類(lèi)和總體結(jié)構(gòu)

2.Four-stage-engine Operation（1學(xué)時(shí)）四行程發(fā)動(dòng)機(jī)工作過(guò)程

3.Two-stage-engine Operation（1學(xué)時(shí)）二行程發(fā)動(dòng)機(jī)工作過(guò)程

4.Diesel Engine Operating Features（1學(xué)時(shí)）柴油發(fā)動(dòng)機(jī)工作特點(diǎn)

5.Engine Cylinder Block Crankcase（1學(xué)時(shí)）發(fā)動(dòng)機(jī)氣缸體

曲軸箱

6.Piston Connecting Rod（1學(xué)時(shí)）活塞

連桿

7.Crankshaft Flywheel（1學(xué)時(shí)）曲軸 飛輪

8.Valves and Vales Train（1學(xué)時(shí)）氣門(mén)與氣門(mén)傳動(dòng)組

9.Engine Fuel System（1學(xué)時(shí)）發(fā)動(dòng)機(jī)燃油系統(tǒng)

10.Engine Lubricating System（1學(xué)時(shí)）發(fā)動(dòng)機(jī)潤(rùn)滑系統(tǒng)

11.Engine Cooling System（1學(xué)時(shí)）發(fā)動(dòng)機(jī)冷卻系統(tǒng)

12.Engine Ignition System（1學(xué)時(shí)）發(fā)動(dòng)機(jī)點(diǎn)火系統(tǒng)

13.Engine Starting System（1學(xué)時(shí)）發(fā)動(dòng)機(jī)起動(dòng)系統(tǒng)

14.Locomotives（2學(xué)時(shí)）機(jī)車(chē)

15.Diesel Traction（3學(xué)時(shí)）內(nèi)燃牽引

三、教學(xué)難點(diǎn)與重點(diǎn)：

重點(diǎn)內(nèi)容有：

1.Engine Classification and Overall Mechanics，發(fā)動(dòng)機(jī)的分類(lèi)和總體結(jié)構(gòu)；2.Four-stage-engine Operation，四行程發(fā)動(dòng)機(jī)工作過(guò)程；4.Diesel Engine Operating Features，柴油發(fā)動(dòng)機(jī)工作特點(diǎn)；5.Engine Cylinder Block Crankcase，發(fā)動(dòng)機(jī)氣缸體

曲軸箱；7.Crankshaft Flywheel，曲軸 飛輪；8.Valves and Vales Train，氣門(mén)與氣門(mén)傳動(dòng)組；9.Engine Fuel System，發(fā)動(dòng)機(jī)燃油系統(tǒng)；10.Engine Lubricating System，發(fā)動(dòng)機(jī)潤(rùn)滑系統(tǒng)；11.Engine Cooling System，發(fā)動(dòng)機(jī)冷卻系統(tǒng)；13.Engine Starting System，發(fā)動(dòng)機(jī)起動(dòng)系統(tǒng)；14.Locomotives，機(jī)車(chē)；15.Diesel Traction，內(nèi)燃牽引。

四、作業(yè)

三篇翻譯

1.Engine Classification and Overall Mechanics

發(fā)動(dòng)機(jī)的分類(lèi)和總體結(jié)構(gòu)

The automobile engines can be classified according to: 1.number of cylinders;2.arrangement of cylinders;3.arrangement of valves;4.type of cooling;5.number of cycles(two or four);6.type of fuel burned;7.type of ignition.汽車(chē)發(fā)動(dòng)機(jī)可以按以下幾種情況分類(lèi)：

1．按氣缸的數(shù)量分類(lèi)；2．按氣缸排列的力式分類(lèi)；3．按進(jìn)氣方式分類(lèi)；4．按冷卻方式分類(lèi)；5．按工作循環(huán)的行程數(shù)分類(lèi)（二行程或四行程）6．按所用的燃料分類(lèi)；7．按點(diǎn)火方式分類(lèi)。

The engine is the source of power that makes the wheels go around and the car move.The automobile engine is an internal-combustion engine because the fuel(gasoline)is burned inside it.The burning of gasoline inside the engine produces high pressure in the engine combustion chamber.This high pressure forces piston to move, the movement is carried by connecting rods to the engine crankshaft.The crankshaft is thus made to rotate;the rotary motion is carried through the power train to the car wheels so that they rotate and the moves.發(fā)動(dòng)機(jī)是使車(chē)輪轉(zhuǎn)動(dòng)、從而驅(qū)動(dòng)汽車(chē)行駛的動(dòng)力來(lái)源。汽車(chē)發(fā)動(dòng)機(jī)是一種內(nèi)燃機(jī)，因?yàn)槿加停ㄆ停┦窃诎l(fā)動(dòng)機(jī)內(nèi)燃燒的。汽油的燃燒在發(fā)動(dòng)機(jī)燃燒室中產(chǎn)生的高壓力，推動(dòng)活塞運(yùn)動(dòng)，并通過(guò)連桿傳到發(fā)動(dòng)機(jī)曲軸。曲軸轉(zhuǎn)動(dòng)，動(dòng)力傳動(dòng)系統(tǒng)將發(fā)動(dòng)機(jī)的轉(zhuǎn)動(dòng)運(yùn)動(dòng)傳給汽車(chē)車(chē)輪，從而使車(chē)輪及整車(chē)轉(zhuǎn)動(dòng)起來(lái)。

The engine requires a fuel system to supply it with a mixture of air and fuel.The fuel system does this by pumping liquid gasoline from a tank into the carburetor, a mixing device that mixes the gasoline with air.The mixture is delivered to the engine where it is burned.發(fā)動(dòng)機(jī)要求燃料供給系統(tǒng)為之供應(yīng)汽油混合燃料。燃料系統(tǒng)把汽油從油箱中抽出來(lái)，通過(guò)化油器--一種把汽油空氣進(jìn)行混合的裝臵--將可燃混合氣輸送到發(fā)動(dòng)機(jī)，并在那里進(jìn)行燃燒。

The engine also needs a cooling system, the combustion of the air-fuel mixture in the engine creates a very high temperature(as high as 2000 to 2700 ℃).The cooling system takes heat away from the engine by circulating a liquid coolant(water mixed with antifreeze)between the engine and a radiator.The coolant gets hot as it goes through the engine.It cools off as it goes through the radiator.Thus, the coolant continually takes heat away from the engine, where it could do damage, and delivers it to the radiator.Air passing through the radiator takes heat away from the radiator.發(fā)動(dòng)機(jī)還配備有冷卻系統(tǒng)，發(fā)動(dòng)機(jī)內(nèi)部的混合氣燃燒會(huì)產(chǎn)生高溫（高達(dá)2，000-2，700℃）。冷卻系統(tǒng)通過(guò)在發(fā)動(dòng)機(jī)和散熱器之間流動(dòng)的液體冷卻液（加了防凍液的水）使發(fā)動(dòng)機(jī)降溫。當(dāng)冷卻液流經(jīng)發(fā)動(dòng)機(jī)時(shí)，冷卻液就會(huì)變熱。而流到散熱器時(shí)又會(huì)被冷卻，這樣使發(fā)動(dòng)機(jī)產(chǎn)生的熱量不斷地被消散掉。經(jīng)過(guò)散熱器的空氣，將熱量從散熱器中帶走。

The engine also includes a lubricating system.The purpose of the lubricating system is to supply all moving parts inside the engine with lubricating oil;the oil keeps moving parts from wearing excessively.發(fā)動(dòng)機(jī)還包括潤(rùn)滑系統(tǒng)，潤(rùn)滑系統(tǒng)的作用是向發(fā)動(dòng)機(jī)內(nèi)的各個(gè)運(yùn)動(dòng)零件提供潤(rùn)滑油。潤(rùn)滑油可是運(yùn)動(dòng)零件免于過(guò)度磨損。

The engine requires a fourth system, the ignition system.The ignition system provides high-voltage electric sparks that ignite, or set fire to, the charges of air-fuel mixture in the engine combustion chambers.發(fā)動(dòng)機(jī)的第四個(gè)系統(tǒng)是點(diǎn)火系統(tǒng)。點(diǎn)火裝臵產(chǎn)生高壓電火花，從而使發(fā)動(dòng)機(jī)燃燒室中的可燃混合氣起燃。

The fifth is starting system and its purpose is to change the electrical current into the mechanical energy to push the crank-shaft around.By means of this, the engine can be started.發(fā)動(dòng)機(jī)的第五個(gè)系統(tǒng)是起動(dòng)系統(tǒng)，起動(dòng)系統(tǒng)的作用是把電能轉(zhuǎn)變?yōu)闄C(jī)械能推動(dòng)曲軸轉(zhuǎn)動(dòng)。發(fā)動(dòng)機(jī)借助這種辦法啟動(dòng)。

These five systems are discussed briefly in following sections.這五個(gè)系統(tǒng)將在以后的章節(jié)中詳細(xì)討論。Words and Expressions combustion chamber 燃燒室；ignition.點(diǎn)燃；power train 動(dòng)力傳動(dòng)系統(tǒng)；carburetor 化油器；antifreeze 防凍的；coolant 冷卻劑（液態(tài)）；crankshaft 曲軸 6

2.Four-stage-engine Operation 四行程發(fā)動(dòng)機(jī)工作過(guò)程

The action taking place in the engine cylinder can be divided into four stages, or strokes.―Stroke‖ refers to piston movement;as stroke occurs when the piston moves from one limiting position to the other.The upper limit of piston movement is called TDC（top dead center）.The lower limit of piston movement is called BDC(bottom dead center).A stroke is piston movement from TDC to BDC or from BDC to TDC.In other words, the piston completes a stroke each time it change its direction of motion.發(fā)動(dòng)機(jī)氣缸內(nèi)的工作過(guò)程，可以分為四個(gè)階段，或行程。行程涉及活塞的運(yùn)動(dòng)；活塞從某一限定位臵到另一限定位臵的運(yùn)動(dòng)稱為一行程。活塞運(yùn)動(dòng)的上限稱為T(mén)DC（上止點(diǎn)），下限稱為BDC（下止點(diǎn)）。一個(gè)行程就是活塞從上止點(diǎn)到下止點(diǎn)，或從下止點(diǎn)到上止點(diǎn)的運(yùn)動(dòng)。換句話說(shuō)，活塞每完成一個(gè)行程，就改變一次其運(yùn)動(dòng)的方向。

Where the entire cycle of events in the cylinder requires four strokes(or two crankshaft revolutions), the engine is called a four-stroke-cycle engine, or a four-cycle engine.The four piston strokes are intake, compression, power, and exhaust.發(fā)動(dòng)機(jī)氣缸中的全部工作過(guò)程分為四個(gè)行程的（或者曲軸旋轉(zhuǎn)兩周的），叫做四行程循環(huán)發(fā)動(dòng)機(jī)，或四循環(huán)發(fā)動(dòng)機(jī)。發(fā)動(dòng)機(jī)的四個(gè)行程是進(jìn)氣、壓縮、做功、排氣。

Intake stroke.On the intake stroke, the intake valve has opened, the piston is moving downward, and a mixture of air and vaporized gasoline is entering the cylinder through the valve port.The mixture of air and vaporized gasoline is delivered to the cylinder by the fuel system and carburetor.進(jìn)氣行程：在進(jìn)氣行程中，進(jìn)氣門(mén)打開(kāi)，活塞向下移動(dòng)，可燃混合氣通過(guò)進(jìn)氣門(mén)進(jìn)入氣缸。適當(dāng)濃度可燃混合氣是由燃料系統(tǒng)和化油器提供的。

Compression stroke.After the piston reaches BDC, or the lower limit of its travel, it begins to move upward.As this happens, the intake valve closes.The exhaust valve 7 is also closed, so that the cylinder is sealed.As the piston moves upward(pushed now by the revolving crankshaft and connecting rod), the air-fuel mixture is compressed.By the time the piston reaches TDC, the mixture has been compressed to as little as one-tenth of its original volume, or even less.This compression of the air-fuel mixture increases the pressure in the cylinder.When the air-fuel mixture is compressed, not only does the pressure in the cylinder go up, but the temperature of the mixture also increases.壓縮行程：在活塞到達(dá)下止點(diǎn)時(shí)，或者是活塞下限時(shí)，活塞開(kāi)始向上運(yùn)動(dòng)。同時(shí)，進(jìn)氣門(mén)關(guān)閉，排氣門(mén)也關(guān)閉，所以這時(shí)的氣缸是封閉的。當(dāng)活塞向上運(yùn)動(dòng)時(shí)（這是由轉(zhuǎn)動(dòng)的曲軸和連桿推動(dòng)活塞），可燃混合氣被壓縮。當(dāng)活塞到達(dá)上止點(diǎn)時(shí)，可燃混合氣被壓縮到只有原體積的在十分之一，甚至更少。當(dāng)油器混合燃料被壓縮時(shí)，不僅氣缸里的壓力上升，可燃混合氣的溫度也隨之增加了。

Power stroke.As the piston reaches TDC on the compression stroke, an electric spark is produced at the spark plug.The ignition system delivers a high-voltage surge of electricity to the spark plug to produce the spark.The spark ignites, or sets fire to, the air-fuel mixture.It now begins to burn very rapidly, and the cylinder pressure increases to as much as 3-5 MPa or even more.This terrific push against the piston forces it downward, and a power impulse is transmitted through the connecting rod to the crankpin on the crankshaft.The crankshaft is rotated as the piston is pushed down by the pressure above it.做功行程：當(dāng)活塞到達(dá)壓縮行程的上止點(diǎn)時(shí)，火花塞產(chǎn)生電火花。電火花是由點(diǎn)火系統(tǒng)向火花塞提供高壓電脈沖而產(chǎn)生的。電火花點(diǎn)燃可燃混合氣。可燃混合氣開(kāi)始發(fā)生劇烈燃燒，氣缸內(nèi)壓力達(dá)到3-5兆帕，甚至更高。作用于活塞上強(qiáng)大的推動(dòng)力推動(dòng)活塞向下運(yùn)動(dòng)，并將這一推力通過(guò)連桿傳到曲軸上的連桿軸頸上。因此，當(dāng)活塞受壓向下運(yùn)動(dòng)時(shí)，推動(dòng)曲軸轉(zhuǎn)動(dòng)。

Exhaust stroke.As the piston reaches BDC again, the exhaust valve opens.Now, as the piston moves up on the exhaust stroke, it forces the burned gases out of the cylinder through the exhaust-valve port.Then, when the piston reaches TDC, the exhaust valve closes and the intake valve opens.Now, a fresh charge of air-fuel mixture will be drawn into the cylinder as the piston moves down again toward BDC.The above four strokes are continuously repeated.排氣行程：當(dāng)活塞再一次到達(dá)下止點(diǎn)時(shí)，排氣門(mén)打開(kāi)。同時(shí)，活塞向上移動(dòng)，把廢氣經(jīng)排氣門(mén)排出氣缸。隨后活塞達(dá)到上止點(diǎn)，排氣門(mén)關(guān)閉，進(jìn)氣門(mén)打開(kāi)。當(dāng)活塞又一次向下移動(dòng)到達(dá)下止點(diǎn)時(shí)，新鮮可燃混合氣被吸入氣缸，上述的四個(gè)行程又繼續(xù)重復(fù)。

Words and Expressions

stroke 行程，沖程；BDC 上止點(diǎn)；TDC 下止點(diǎn)；surge 沖擊，脈動(dòng)；terrific 了不起的，絕妙的；crankpin 曲柄銷(xiāo)，連桿軸頸；intake stroke 吸氣沖程；compression stroke 壓縮沖程；power stroke 做功沖程；exhaust stroke 排氣沖程；fresh charge（發(fā)動(dòng)機(jī)）吸入的新鮮混合油氣

3.Two-stage-engine Operation 二行程發(fā)動(dòng)機(jī)工作過(guò)程

In the four-stroke-cycle engine, already discussed in lesson 1、2, the complete cycle of events requires four piston strokes(intake, compression, power, and exhaust).In the two-stroke-cycle, or two-cycle, engine, the intake and compression strokes and power and exhaust strokes are in a sense combined.This permits the engine to produce a power stroke every two piston strokes, or every crankshaft rotation.我們?cè)诘诙n中講到，四行程發(fā)動(dòng)機(jī)整個(gè)工作循環(huán)需要活塞完成進(jìn)氣、壓縮、做功、排氣四個(gè)行程。在二行程發(fā)動(dòng)機(jī)中，進(jìn)氣和壓縮行程以及做功和排氣行程是分別合并在一起的，這使得二行程發(fā)動(dòng)機(jī)每?jī)蓚€(gè)行程，即曲軸旋轉(zhuǎn)一周，就完成一次工作循環(huán)。

In the two-cycle engine, the piston acts as a valve, clearing valve ports in the cylinder wall as it nears BDC.A fresh air-fuel charge enters through the intake port, and the burned gases exit through the exhaust port.The complete cycle of operation is as follows: As the piston nears TDC, ignition takes place.The high combustion pressures drive the piston down, and the thrust through the connecting rod turns the crankshaft.As the piston nears BDC，it passes the intake and exhaust ports in the cylinder wall.Burned gases, still under some pressure, begin to stream out through the exhaust port.At the same time, the intake port, now cleared by the piston, begins to deliver air-fuel mixture, under pressure, to the cylinder.The top of the piston is shaped to give the incoming mixture an upward movement.This helps to sweep the burned gases ahead and out through the exhaust port.在二行程發(fā)動(dòng)機(jī)中，活塞起到閥門(mén)的作用，當(dāng)活塞接近下止點(diǎn)時(shí)，使氣缸壁上的進(jìn)排氣口打開(kāi)。新的可燃混合氣通過(guò)進(jìn)氣口進(jìn)入，燃燒過(guò)的廢氣從排氣口排出。整個(gè)工作過(guò)程如下：當(dāng)活塞接近上止點(diǎn)時(shí)，發(fā)動(dòng)機(jī)點(diǎn)火，燃燒產(chǎn)生的高壓驅(qū)動(dòng)活塞向下運(yùn)動(dòng)，通過(guò)連桿，推動(dòng)曲軸轉(zhuǎn)動(dòng)。當(dāng)活塞接近下止點(diǎn)時(shí)，經(jīng)過(guò)氣缸壁上的進(jìn)排氣口，燃燒過(guò)的氣體，仍有剩余壓力，開(kāi)始從排氣口噴出。同時(shí)，活塞使進(jìn)氣口露出，受壓縮的可燃混合氣開(kāi)始進(jìn)入氣缸?；钊敳康男螤钍惯M(jìn)入氣缸的可燃混合氣向上運(yùn)動(dòng)，這樣有助于掃氣，引導(dǎo)燃燒過(guò)的廢氣向上運(yùn)動(dòng)并從排氣 10 口排出。

After the piston has passed through BDC and stars up again, it passes both ports, thus sealing them off.Now the fresh air-fuel charge above the piston is compressed and ignited.The same series of events takes place again and continue as long as the engine runs.在活塞通過(guò)下止點(diǎn)，并開(kāi)始上升時(shí)，活塞經(jīng)過(guò)進(jìn)氣口和排氣口，將其堵住。這時(shí)候活塞上方新的可燃混合氣受壓縮后點(diǎn)火。只要發(fā)動(dòng)機(jī)運(yùn)轉(zhuǎn)，同樣的動(dòng)作就會(huì)反復(fù)不斷地發(fā)生。

We mentioned that the air-fuel mixture is delivered to the cylinder under pressure.In most engines, this pressure is put on the mixture in the crankcase.The crankcase is sealed except for a leaf, or reed, valve at the bottom.The reed valve is a flexible, flat metal plate that rests snugly against the floor of the crankcase.There are holes under the reed valve that connect to the engine carburetor.When the piston is moving up, a partial vacuum is produced in the sealed crankcase.Atmospheric pressure lifts the reed valve off the holes, and air-fuel mixture enters the crankcase.After the piston passes TDC and starts down again, pressure begins to build up in the crankcase.This pressure closes the reed valve so that further downward movement of the piston compresses the tapped air-fuel mixture in the crankcase.The pressure which is built up on the air-fuel mixture then causes it to flow up through the intake port into the engine cylinder when the piston moves down far enough to clear the intake port.我們?cè)岬娇扇蓟旌蠚馐潜粔哼M(jìn)氣缸的。在大多數(shù)發(fā)動(dòng)機(jī)中，可燃混合氣是在曲軸箱中受壓的。除了底部有一葉片閥（片簧閥）之外，曲軸箱是密封的。片簧閥是一片柔韌、平整的金屬片。金屬片緊貼在曲軸箱的底部。在片簧閥的下面有孔道與化油器相連。當(dāng)活塞向上運(yùn)行時(shí)，就會(huì)在密封的曲軸箱里產(chǎn)生部分真空。大氣的壓力將片簧閥提起。打開(kāi)通道，可燃混合氣進(jìn)入曲軸箱。當(dāng)活塞經(jīng)過(guò)上止點(diǎn)，又開(kāi)始向下運(yùn)動(dòng)時(shí)，壓力就開(kāi)始在曲軸箱中產(chǎn)生。壓力使片簧閥關(guān)閉，這樣，活塞進(jìn)一步的向下運(yùn)動(dòng)壓縮留在曲軸箱中的可燃混合氣。當(dāng)活塞向下運(yùn)動(dòng)直到露出進(jìn)氣口，可燃混合氣所具有的壓力使其上升，通過(guò)進(jìn)氣口進(jìn)入氣缸。

The two-stroke engine is not only very simple but gives nearly twice the power 11 of a four stroke engine from a cylinder of given size, but it is wasteful of gasoline, as some mixture inevitably finds its way into the exhaust system on the combines intake/exhaust stroke, and there are always some combustion products left in the cylinder which reduce the rapid burning of the fuel.This kind of engine is always used in motorcycles.二行程發(fā)動(dòng)機(jī)不僅結(jié)構(gòu)簡(jiǎn)單，而且其功率相當(dāng)于具有相同氣缸容積的四行程發(fā)動(dòng)機(jī)的二倍。但是，在進(jìn)氣和排氣行程中，一些可燃混合氣不可避免地進(jìn)入排氣系統(tǒng)，并且總會(huì)有一些燃燒物滯留在氣缸中，致使燃料不能充分燃燒。所以二行程發(fā)動(dòng)機(jī)耗油較大。通常使用在摩托車(chē)上。

Words and Expressions sweep 掃氣；connecting rod

連桿；crankcase 曲軸箱；seal off 密封；leaf（reed）valve 片簧閥；air-fuel charge 可燃混合油氣

4.Diesel Engine Operating Features

柴油發(fā)動(dòng)機(jī)工作特點(diǎn)

We all know that diesel engines, in principle, work in the same way as gasoline engines do.Both kinds of engines are internal-combustion engines, but each of them has its characteristic features.As their names suggest this type of engines burn their fuel inside the working parts of the engines.―Internal‖ means ―inside‖, ―combustion‖ means ―catching fire or burning‖.In any internal combustion engine, burning fuel heats air which consequently expands, and in expanding exists a push to a piston which, in turn, rotates the engine crankshaft through a connecting rod.我們都知道柴油機(jī)和汽油機(jī)的工作原理是相同的。這兩種發(fā)動(dòng)機(jī)都是內(nèi)燃機(jī)，但各自卻具有自身的特點(diǎn)。正如這一類(lèi)型發(fā)動(dòng)機(jī)的名稱所提示的，發(fā)動(dòng)機(jī)的燃料是在發(fā)動(dòng)機(jī)工作部件的內(nèi)部燃燒的。―internal‖意思是―內(nèi)部‖，―combustion‖意思是―著火或燃燒‖。在任何內(nèi)燃機(jī)中，燃燒的燃料使空氣受熱并迅速膨脹，產(chǎn)生推力推動(dòng)活塞，通過(guò)連桿推動(dòng)發(fā)動(dòng)機(jī)的曲軸。

Now let us compare the diesel engine with the gasoline engine.Firstly, the explosive mixture of the gasoline engine is provided by a carburetor, but in the case of the diesel engine the supply is affected by an injection or ―jerk‖ pump which forces a ―short‖ of fuel into each cylinder in turn according to the correct firing sequence.Secondly, the fundamental difference between gasoline and diesel engines is that in the gasoline engine the source of the heat for igniting the charge, namely, an electric spark, is generated outside the engine, and is taken, as it were, into the waiting charge at the required instant.In the diesel engine the source of heat for igniting the charge is created within the engine by compressing pure air to a degree that will initiate combustion and then injecting the fuel at the right time in relation to the movement of the crankshaft.Both classes of engines are of very similar construction.But as the diesel engine is called upon to withstand very much greater stresses due to higher pressures in cylinders, it has to be of more substantial construction, and is thus heavier.In general, the diesel engine may weigh about 9.25 kilograms per kilowatt.The most important advantage of the gasoline engine is its lower weight per kilowatt.The gasoline engine for automobiles weighs about 6.17 kilograms per kilowatt, and gasoline engines for airplanes may weigh as little as 0.77 kilograms per kilowatt.This advantage prevents the diesel engine from replacing the gasoline engine in some automobiles and airplanes.現(xiàn)在，讓我們比較一下柴油機(jī)和汽油機(jī)。首先，汽油機(jī)的可燃混合氣是由化油器提供的，而柴油機(jī)由噴油泵或脈動(dòng)泵按照正確的點(diǎn)火順序?qū)⑷加洼喠鞯膰娙敫鳉飧椎?。第二，汽油發(fā)動(dòng)機(jī)與柴油發(fā)動(dòng)機(jī)的基本區(qū)別在于汽油機(jī)中點(diǎn)燃混合氣的熱源是電火花。電火花是在發(fā)動(dòng)機(jī)外面產(chǎn)生的。按照實(shí)際情況來(lái)說(shuō)，電火花總是在需要的時(shí)刻進(jìn)入待燃的混合氣中。在柴油發(fā)動(dòng)機(jī)中，使燃油點(diǎn)火的熱源是靠將空氣壓縮到可以引燃的程度來(lái)產(chǎn)生的，并在對(duì)應(yīng)于曲軸轉(zhuǎn)動(dòng)的恰當(dāng)時(shí)刻噴入燃料。這兩類(lèi)機(jī)型結(jié)構(gòu)是很相似的，但是由于氣缸要產(chǎn)生較大的壓力，而要求柴油發(fā)動(dòng)機(jī)能夠經(jīng)受非常大的應(yīng)力，它的結(jié)構(gòu)就需要更加堅(jiān)固，其質(zhì)量也因此就得更大。一般來(lái)說(shuō)，柴油機(jī)比質(zhì)量約為9.25公斤每千瓦。汽油機(jī)最重要的優(yōu)點(diǎn)是每千瓦的質(zhì)量較輕。汽車(chē)用汽油發(fā)動(dòng)機(jī)比質(zhì)量為6.17公斤每千瓦，而飛機(jī)用汽油發(fā)動(dòng)機(jī)的比質(zhì)量小到0.77公斤每千瓦。汽油機(jī)的這一優(yōu)點(diǎn)使柴油機(jī)無(wú)法代替某些汽車(chē)以及飛機(jī)上使用的汽油發(fā)動(dòng)機(jī)。

However, the diesel engine is more efficient, because it has higher compression ration.Its ratio may be as high as 16 to 1.Up to 40 percent of the chemical energy of the burning fuel may be changed into mechanical energy.In addition, the diesel engine runs cooler than the gasoline engine.This advantage is especially obvious at lower speeds.Diesel oil is not only cheaper than gasoline, but also safer to store.但是，柴油發(fā)動(dòng)機(jī)的效率更高些，因?yàn)椴裼蜋C(jī)具有較高的壓縮比—16比1。高達(dá)百分之四十的燃料燃燒產(chǎn)生的化學(xué)能轉(zhuǎn)化為機(jī)械能。此外，柴油發(fā)動(dòng)機(jī)比汽油發(fā)動(dòng)機(jī)的運(yùn)轉(zhuǎn)溫度低。這一優(yōu)點(diǎn)在運(yùn)轉(zhuǎn)速度低時(shí)尤為明顯，柴油不僅比汽油便宜，而且貯存更為安全。

Words and Expressions diesel：柴油機(jī)； internal-combustion engines：內(nèi)燃機(jī)； jerk pump：脈動(dòng)史噴油泵；compression ration：壓縮比

5.Engine Cylinder Block Crankcase

發(fā)動(dòng)機(jī)氣缸體

曲軸箱

We have seen how the mixture of air and fuel is delivered by the fuel system to the engine cylinder, where it is compressed, ignited, and burned.We have noted that this combustion produces a high pressure that pushes the piston down so that the crankshaft is rotated.Now let us examine the various parts of the engine in detail.我們已經(jīng)了解油氣混合燃料是如何通過(guò)燃料供給系統(tǒng)輸送到發(fā)動(dòng)機(jī)氣缸的，并在氣缸中壓縮、點(diǎn)火、燃燒。我們已知道燃燒產(chǎn)生高壓，并推動(dòng)活塞下行，帶動(dòng)曲軸轉(zhuǎn)動(dòng)?，F(xiàn)在讓我們?cè)敿?xì)研究一下發(fā)動(dòng)機(jī)的各部分結(jié)構(gòu)。

Engine cylinder block The cylinder block of liquid-cooled engines forms the basic framework of the engine.Other parts are attached to the cylinder block or are assembled in it.The block is cast in one piece from gray iron or iron alloyed with other metals, such as nickel or chromium.Some blocks are cast from aluminum.The block contains not only the cylinders but also the water jackets that surround them.In aluminum blocks, cast-iron or steel cylinder sleeves(also called bore lines)are used.These metals have better wearing qualities than aluminum and can better withstand the wearing effect of the pistons and ring moving up and down in the cylinders.For most engines, cast iron has been found to be a satisfactory cylinder-wall material.However, in some small engines, the cylinder walls are plated with chromium, a very hard metal, to reduce wall wear and lengthen their life.發(fā)動(dòng)機(jī)氣缸體

水冷發(fā)動(dòng)機(jī)的氣缸體是發(fā)動(dòng)機(jī)的基本構(gòu)件，其它部件都支承或安裝在它上面。缸體是由灰鑄鐵或含有鎳或鉻的合金鑄鐵整體鑄造而成的。有的缸體由鋁澆鑄而成。缸體不僅包括氣缸，而且包括環(huán)繞的水套。由鋁鑄造的氣缸中，裝有鑄鐵或鋼制的氣缸套（或稱之為氣缸襯套）。這類(lèi)金屬的耐磨性比鋁更好，能更好地經(jīng)受住活塞和活塞環(huán)在氣缸中上下運(yùn)動(dòng)產(chǎn)生的磨損。在大部分發(fā)動(dòng)機(jī)中，采用鑄鐵作為氣缸壁面的良好材料。而在一些小型發(fā)動(dòng)機(jī)中，氣缸壁面鍍鉻，鉻是一種非常耐磨的金屬，可減少氣缸壁的磨損并延長(zhǎng)使用壽命。Cylinder Head The cylinder head is usually cast in one piece from iron, from iron alloyed with other metals, or from aluminum alloy.Aluminum has the advantage of combining lightness with high heat conductivity.That is, an aluminum head tends to turn cooler, other factors being equal.There are two types of head, L head and I head.Cylinder head contains water jackets for cooling;in the assembled engine, these water jackets are connected through openings to the cylinder-block water jackets.Spark-plug holes are provided, along with pockets into which the valves can move as they open.氣缸蓋

氣缸蓋通常由鐵、鐵合金或鋁合金鑄成。鋁兼有重量輕、導(dǎo)熱好的優(yōu)點(diǎn)。也就是說(shuō)，其它因素一樣時(shí)，鋁蓋更容易冷卻。有兩種氣缸，L型氣缸蓋和I型氣缸蓋。氣缸蓋帶有用于冷卻的水套。在裝配發(fā)動(dòng)機(jī)時(shí)，這些水套通過(guò)出水口與氣缸氣缸蓋上留有火花塞口和凹槽，凹槽使氣門(mén)打開(kāi)時(shí)可以移動(dòng)。

Gaskets The joint between the cylinder block and the head must be tight and able to withstand the pressure and heat developed in the combustion chambers.The block and head cannot be machined flat and smooth enough to provide an adequate seal.Thus, gaskets are used.Head gaskets are made of thin sheets of soft metal or asbestos and metal.All cylinder, water, valve, and head-bolt openings are cut out.When the gasket is placed on the block and the head installed, tightening of the head bolts(or nuts)squeezes the soft metal so that the joint is effectively sealed.Gaskets are also used to seal joints between other parts, such as between the oil pan, manifolds, or water pump and the block.氣缸墊

氣缸體與氣缸蓋之間的結(jié)合處必須保持密封，并且能夠承受燃燒室產(chǎn)生的高壓和高溫。機(jī)器加工并不能使氣缸體和氣缸蓋平整光滑到嚴(yán)絲密縫，這樣就要使用氣缸墊。氣缸蓋用的密封墊是用軟金屬薄片或金屬和石棉組成的薄片制成，留出所有的氣缸孔、水道孔、氣門(mén)孔和氣缸蓋螺栓孔。當(dāng)氣缸墊裝在氣缸體上，然后裝上氣缸蓋以后，氣缸蓋螺栓就壓緊軟金屬墊，這樣結(jié)合處就完全密封了。密 封墊也同樣用于密封其它部件之間的結(jié)合處，例如，油底殼、歧管、水泵與氣缸體之間的密封。

Oil Pan The oil pan is usually formed of pressed steel.It usually holds 5 to 10 litres of oil, depending on the engine design.The oil pan and the lower part of the cylinder block together are called the crankcase;they enclose, or encase, the crankshaft.The oil pump in the lubricating system draws oil from the oil pan and sends it to all working parts in the engine.The oil drains off and runs down into the pan.Thus, there is constant circulation of oil between the pan and the working parts of the engine.油盤(pán)

油盤(pán)通常用薄鋼板沖壓制成。依其設(shè)計(jì)不同，油盤(pán)的容量通常由5到10升不等。油盤(pán)和氣缸體的下部共同稱為曲軸箱，用來(lái)密封或罩住曲軸。潤(rùn)滑系統(tǒng)中的油泵把機(jī)油從油中抽上來(lái)，送到發(fā)動(dòng)機(jī)的各個(gè)活動(dòng)部件。機(jī)油再流下來(lái)回到油盤(pán)。這樣，機(jī)油就在和發(fā)動(dòng)機(jī)的各個(gè)部件之間不斷循環(huán)流動(dòng)。

Words and Expressions cylinder block 氣缸體；block crankcase 曲軸箱；framework 結(jié)構(gòu)，車(chē)架；

gray iron 灰鑄鐵；water jacket 水套； plate……with 鍍金屬；cylinder head

氣缸蓋；gaskets 密封墊；asbestos 石棉；manifold 岐管；oil pan 油盤(pán)；

pocket 凹槽；bore liner 氣缸襯套

6.Piston Connecting Rod

活塞

連桿

Piston The piston is essentially a cylindrical plug that moves up and down in the engine cylinder.It is equipped with piston rings to provide a good seal between the cylinder wall and piston.The piston absorbs heat from the gas, and this heat must be carried away if the metal temperature is to be carried away if the metal temperature is to be held within safe limits.The constant reversal of the piston travel sets up inertial forces, which increase both with the weight of the piston and with its speed.For this reason, designers try to keep piston weight low, particularly in high-speed engines.As lower hood lines and over-square engines became popular, the semi-slipper and full-slipper pistons came into use.On these pistons the number piston rings was reduced to three, two compression and one oil-control.One reason for the slipper piston is that, on the short stroke, over-square engine, the piston skirt had to be cut away to make room for the counterweights on the crankshaft.Also, the slipper piston, being shorter and having part of its skirt cut away, is lighter.This reduces the inertial load on the engine bearings and, in addition, makes for a more responsive engine.The lighter the piston, the less the bearing load and the longer the bearings will last.Another way to lighten the piston is to make it of light metal.The idea piston material would be light and strong, conduct heat will, expand only slight when heated, resist wear, and be low in cost.Thus, most automotive-engine pistons today are made of aluminum, which is less than half as heavy as iron.Iron pistons were common in the earlier engines.Aluminum expands more rapidly than iron with increasing temperature, however, and since the cylinder block is of iron, special provisions must be made to maintain proper piston clearance at operating temperatures.To take care of it, the crown is machined on slight taper, the diameter being greatest where the crown meets the skirt and becoming less toward the top.活塞

實(shí)質(zhì)上活塞是一個(gè)在氣缸中上下移動(dòng)的圓筒狀的塞子。上面裝有活塞環(huán)，從 18 而使活塞和氣缸壁之間具有良好的密封性?；钊麖臍怏w中吸熱，假如要使金屬的溫度保持在安全限度以內(nèi)，就必須散熱?；钊牟粩嗤鶑?fù)運(yùn)動(dòng)產(chǎn)生了慣性力，慣性力隨活塞的重量及其速度的增加而增大。為此，設(shè)計(jì)者設(shè)法使活塞造的輕些，特別是高速發(fā)動(dòng)機(jī)。由于低發(fā)動(dòng)機(jī)罩和短行程發(fā)動(dòng)機(jī)的進(jìn)一步普及，半圍延裙活塞和滑裙式活塞開(kāi)始使用。在這些活塞中，活塞環(huán)的數(shù)量減少到三個(gè)，即兩個(gè)氣環(huán)，一個(gè)油環(huán)。使用滑裙活塞的原因是：短行程發(fā)動(dòng)機(jī)需除去部分活塞裙部，從而為曲軸的平衡重讓出空間。滑動(dòng)活塞長(zhǎng)度較短，由于裙部被部分切除后重量較輕。這就減少了發(fā)動(dòng)機(jī)軸承上的慣性負(fù)荷，使發(fā)動(dòng)機(jī)反應(yīng)更加靈敏?；钊捷p，軸承的負(fù)荷越小，軸承的工作壽命就越長(zhǎng)。還有一種可使活塞質(zhì)量減小的辦法，就是用輕金屬制造活塞。理想的活塞材料應(yīng)該重量輕、強(qiáng)度高、導(dǎo)熱好、熱膨脹小、耐磨、價(jià)格低廉。因此今天大多數(shù)的汽車(chē)發(fā)動(dòng)機(jī)活塞都是鋁制成的，鋁的重量還不到鑄鐵的一半。鑄鐵活塞在早期的發(fā)動(dòng)機(jī)中廣泛使用。隨著溫度的增加，鋁比鑄鐵膨脹量更大。然而，由于氣缸體是鑄鐵制成的，必須采取特殊的措施，以維持工作溫度下正常的活塞間隙。考慮到這一點(diǎn)，活塞頂部要加工成略呈錐狀體，即活塞頂部與活塞裙部交接處直徑最大，愈向頂部，直徑愈小。

Piston Rings A good seal must be maintained between the piston and cylinder wall to prevent blow-by.―Blow-by‖ is the name that describes the escape of burned gases from the combustion chamber, past the piston, and into the crankcase.In other words, these gases ―blow by‖ the piston.It is not practical to fit the piston to the cylinder closely enough to prevent blow-by.Thus, piston rings must be used to provide the necessary seal.The rings are installed in grooves in the piston.Actually, there are two types of rings, compression rings and oil-control rings.The compression rings seal in the air-fuel mixture as it is compressed and also the combustion pressures as the mixture burns.The oil-control rings scrape off excessive oil from the cylinder wall and return it to the oil pan.活塞環(huán)

在活塞與氣缸壁之間必須保持良好的密封以防止漏氣。―漏氣‖這一名稱是指燃燒氣體從燃燒室溢出，經(jīng)過(guò)活塞進(jìn)入曲軸箱。換句話說(shuō)，這些氣體是通過(guò)活塞溢出的。實(shí)際上，活塞與氣缸間再嚴(yán)密也免不了會(huì)漏氣。所以活塞環(huán)就用來(lái)提供 必要的密封。活塞環(huán)裝在活塞的凹槽中。事實(shí)上有兩種活塞環(huán)，氣環(huán)和油環(huán)。當(dāng)可燃混合氣壓縮時(shí)，氣環(huán)密封可燃混合氣；當(dāng)可燃混合氣燃燒時(shí)氣環(huán)可阻止所產(chǎn)生的壓力不外溢。油環(huán)的作用是刮去氣缸壁上多余的機(jī)油，使之流回油底殼。

The rings have joints(they are split)so that they can be expanded and slipped over the piston head and into the recessed grooves cut in the piston.Rings for automotive engines usually have butt joints, but in some heavy-duty engines, the joints may be angles, lapped, or of the sealed type.活塞環(huán)有接口（也就是有一縫隙）。這樣可以使端部擴(kuò)張并滑入活塞上的凹槽中。汽車(chē)發(fā)動(dòng)機(jī)上的活塞環(huán)通常有接口。但在一些重型發(fā)動(dòng)機(jī)上，活塞環(huán)的接口可以是斜角接口、搭接式或是密封式的。

The rings are somewhat larger in diameter than they will be when in the cylinder.Then, when they are installed, they are compresses so that the joints are nearly closed.Compressing the rings gives them an initial tension;they press tightly against the cylinder wall.活塞環(huán)的直徑要略大于裝入氣缸時(shí)的直徑。這樣，在活塞環(huán)裝入氣缸中時(shí)，活塞環(huán)就會(huì)被壓縮，接頭幾乎閉合了。受壓使之具有預(yù)張力，活塞環(huán)就緊緊地壓在氣缸壁上。

Connecting Rod The connecting rod is attached at one end to a crankpin on the crankshaft and at the other to a piston, through a piston pin or wrist pin.The connecting rod must be very strong and rigid and also as light as possible.The connecting rod carries the power thrusts from the piston to the crankpin.At the same time, the rod is in eccentric motion.To minimize vibration and bearing loads, the rod must be light in weight.To maintain good engine balance, connecting rods and caps are carefully matched in sets for engines.All rods in an engine must be of equal weight;if they are not, noticeable vibration may result.In original assembly, rods and caps are individually matched to each other and usually carry identifying numbers so they will not be mixed if the engine is disassembled for service.They must not be mixed during any service job, since this could result in poor bearing fit and bearing failure.連桿

連桿的一端與曲軸的連桿軸頸相連，另一端通過(guò)活塞銷(xiāo)與活塞相連。連桿必須具有足夠的強(qiáng)度和剛度，并且要盡可能輕。連桿的作用是將活塞承受的壓力傳給連桿軸頸。同時(shí)，連桿做偏心運(yùn)動(dòng)。為了把振動(dòng)和軸承負(fù)荷減小到最低限度，連桿的重量必須盡可能的輕。為了保持發(fā)動(dòng)機(jī)的良好平衡，連桿和連桿蓋都要精心配套。發(fā)動(dòng)機(jī)連桿的質(zhì)量都必須相等，否則，就會(huì)產(chǎn)生明顯的振動(dòng)。在進(jìn)行裝配時(shí)，連桿和連桿蓋都必須一一相互匹配。為了防止拆裝發(fā)動(dòng)機(jī)時(shí)發(fā)生匹配錯(cuò)誤，通常在部件上刻上標(biāo)號(hào)。在維修過(guò)程中，千萬(wàn)不能弄混，因?yàn)檫@會(huì)造成軸承不配套及軸承的損壞。

Words and Expressions counterweight

平衡重；groove 凹槽；recess 凹口；lap 搭接；eccentric 偏心的；lower hood lines 低發(fā)動(dòng)機(jī)罩；over-square engine 短行程發(fā)動(dòng)機(jī)；semi-slipper piston 半裙式活塞；full-slipper piston

全裙式活塞；match in set 配套；blow-by 漏氣；initial tension 初張力；poor bearing fit 軸承不配套； bearing failing 軸承故障。21

7.Crankshaft Flywheel

曲軸 飛輪

Crankshaft The crankshaft is a one-piece casting or forging of heat-treated alloy steel of considerable mechanical strength.The crankshaft must be strong enough to take the downward thrusts of the pistons during the power strokes without excessive distortion.In addition, the crankshaft must be carefully balanced to eliminate undue vibration resulting from the weight of the offset cranks.To provide balance, crankshafts have counterweights opposite the cranks.Crankshafts have drilled oil passages through which oil can flow from the main to the connecting-rod bearings.The front end of the crankshaft carries three devices, the gear or sprocket that drives the camshaft, the vibration damper, and the fan belt pulley.The pulley drives the engine fan, water pump, and generator with a V belt.曲軸

曲軸是由合金鑄造或鍛造，經(jīng)過(guò)熱處理，具有一定的機(jī)械強(qiáng)度的整體結(jié)構(gòu)。曲軸必須具有足夠的強(qiáng)度，以承受活塞在做功行程期間向下運(yùn)動(dòng)產(chǎn)生的沖力，而不會(huì)產(chǎn)生過(guò)度的扭曲。另外，曲軸必須仔細(xì)地給予平衡，以避免曲柄重力偏移而引起過(guò)度振動(dòng)。為了保持平衡，曲軸必須具有與曲柄相對(duì)應(yīng)的平衡重。曲軸上鉆有油道，潤(rùn)滑油可以從主軸承流到連桿軸承上。在曲軸的前端有三個(gè)裝臵：驅(qū)動(dòng)凸輪軸的齒輪或鏈輪、減震器和風(fēng)扇皮帶輪。皮帶輪通過(guò)V形皮帶驅(qū)動(dòng)發(fā)動(dòng)機(jī)風(fēng)扇，水泵和發(fā)電機(jī)。

Flywheel The flow of power from the engine cylinders is not smooth.Although the power impulses overlap(on six-and eight-cylinder engines), there are times when more power is being delivered than at other times.This tends to make the crankshaft speed up and then slow down.However, the flywheel combats the tendency.The flywheel is a comparatively heavy wheel bolted to the rear end of the crankshaft.The inertia of the flywheel tends to keep it turning at constant speed.Thus, the flywheel absorbs energy as the crankshaft tries to speed up and gives back energy as the crankshaft tries to slow down.In effect, the flywheel absorbs power from the engine during the power stroke(or speedup time)and then gives it back to the engine during the other three strokes(or slowdown time)of the cycle.飛輪

發(fā)動(dòng)機(jī)氣缸所產(chǎn)生的動(dòng)力是不均勻的。盡管在六缸或八缸發(fā)動(dòng)機(jī)中，動(dòng)力沖擊重疊發(fā)生，但是有時(shí)產(chǎn)生的動(dòng)力會(huì)大些。這會(huì)使曲軸的運(yùn)轉(zhuǎn)速度忽快忽慢，然而飛輪可以克服這種傾向。飛輪是一個(gè)很重的輪子，用螺栓固定在曲軸的后端。飛輪的慣性使飛輪保持恒速運(yùn)動(dòng)。這樣，飛輪在曲軸加速時(shí)把能量貯存起來(lái)，當(dāng)曲軸速度減慢時(shí)再釋放出來(lái)。事實(shí)上，飛輪在做功行程（或加速過(guò)程）中貯存動(dòng)能，而在其它三個(gè)行程（或減慢過(guò)程）中，把動(dòng)能釋放出來(lái)。

Words and Expressions forging 鍛件；sprocket 扣鏈齒（鏈輪上與鏈條結(jié)合的齒）；damper 減震器；flywheel 飛輪；bolt 螺栓；one-piece 整體 23

8.Valves and Vales Train 氣門(mén)與氣門(mén)傳動(dòng)組

Valves and Valve Train There are two openings, or ports, in the enclosed end of the cylinder.One of the ports permits the mixture of air and gasoline vapor to enter the cylinder.The other port permits the burned gases, after combustion, to exhaust, or escape, from the cylinder.The two ports have valves assembled into them.These valves close off one or the other port, or both ports, during the various stages of engine operation.That is to say, each cylinder has two valves, an intake valve and exhaust valve.The cam lobes on the camshaft are so related to the crankshaft crankpins through the gear or sprockets and chain as to cause the valves to open and close with the correct relationship to the piston strokes.氣門(mén)和氣門(mén)機(jī)構(gòu)

在氣缸封閉的一端，有兩個(gè)開(kāi)口，或稱為孔。一個(gè)開(kāi)口使可燃混合氣可以及時(shí)進(jìn)入氣缸。另一個(gè)開(kāi)口是讓燃燒后的氣體從氣缸內(nèi)排出。這兩個(gè)開(kāi)口都裝有氣門(mén)。這些氣門(mén)在發(fā)動(dòng)機(jī)工作順序的不同階段，關(guān)閉一個(gè)開(kāi)口，（或另一個(gè)開(kāi)口），或者同時(shí)關(guān)閉兩個(gè)開(kāi)口。也就是說(shuō)，每個(gè)氣缸有兩個(gè)氣門(mén)，即進(jìn)氣門(mén)和排氣門(mén)。凸輪軸上的凸輪和凸角通過(guò)齒輪或鏈輪和鏈條與曲軸軸頸相連，這樣，可以使氣門(mén)按照活塞行程的正確順序開(kāi)啟和關(guān)閉。

The valves are nothing more than accurately machined metal plugs(on long stems)that close the openings when they are seated(have moved up into the openings).When the valve closes, it moves up so that the outer edge rests on the seat.In this position, the valve port is closed so that air or gas cannot escape from the cylinder.氣門(mén)不過(guò)是裝在閥桿上加工精細(xì)的金屬塞而已。當(dāng)氣門(mén)就位時(shí)（向上移動(dòng)閥口），即可將氣門(mén)關(guān)閉。氣門(mén)關(guān)閉時(shí)，氣門(mén)向上移動(dòng)，這樣氣門(mén)的邊緣就正好落在氣門(mén)座上。在這一位臵上，氣門(mén)口關(guān)閉，混合氣就不會(huì)從氣缸中逸出。

A spring on the valve stem tends to hold the valve on its seat(closed).The lower 24 end of the spring rests against the cylinder head.The upper end rests against a flat washer, or spring retainer, which is attached to the valve stem by a retainer lock(also called a keeper).The spring is under compression, which means that it tries to expand and therefore spring-loads the valve in the closed position.氣門(mén)桿上的彈簧使氣門(mén)保持在氣門(mén)座上（關(guān)閉狀態(tài)）。彈簧的下端抵在氣缸蓋上。上端抵在彈簧座上，在彈簧座的下面用拴銷(xiāo)（或叫做定位銷(xiāo)）加以定位。彈簧處于―壓縮‖狀態(tài)時(shí)，意味著彈簧試圖伸展，氣門(mén)受彈簧作用而處于關(guān)閉狀態(tài)。

A valve-opening mechanism opens the valve, or lifts it off its seat, at certain times.On most engines, this mechanism, called the valve train, includes a cam on the camshaft, a valve lifter, a push rod, and a rocker arm.As the camshaft turns, the cam lobe comes around under the valve lifter.This raises the lifter, which in turn pushes upward on the push rod.The push rod, as it is lifted, causes the end of the rocker arm to move up.The rocker arm pivots around its supporting shaft so that the valve en of the rocker arm is forced downward.This downward movement forced the valve to move downward off its seat so that it opens.After the cam lobe moves out from under the valve lifter, the valve spring forces the valve up onto its seat again.使氣門(mén)開(kāi)啟的機(jī)械裝臵在適當(dāng)?shù)臅r(shí)刻開(kāi)啟氣門(mén)或者將氣門(mén)從氣門(mén)座上提起。在大多數(shù)發(fā)動(dòng)機(jī)中，這套裝臵叫做氣門(mén)機(jī)構(gòu)。這套裝臵中包括凸輪軸上的一個(gè)凸輪、一個(gè)氣門(mén)挺桿、一個(gè)氣門(mén)推桿和一個(gè)搖臂。當(dāng)凸輪軸轉(zhuǎn)動(dòng)時(shí)，凸輪凸角轉(zhuǎn)到氣門(mén)挺桿下面，是挺桿上舉，挺桿推動(dòng)推桿。當(dāng)推桿升起時(shí)，搖臂的端部向上移動(dòng)。搖臂圍繞支承軸旋轉(zhuǎn)，氣門(mén)與搖臂相對(duì)應(yīng)的一端壓下。向下的運(yùn)動(dòng)使氣門(mén)向下移動(dòng)離開(kāi)氣門(mén)座，氣門(mén)被打開(kāi)。當(dāng)凸輪凸角離開(kāi)氣門(mén)挺桿，氣門(mén)彈簧使氣門(mén)重新回到氣門(mén)座上。

In the other kind of valve mechanism for an engine, the valves are located in the cylinder block instead of the head.With this arrangement, the camshaft is directly below the valve lifter, and no push rods or rocker arms are necessary.Although the valve-in-block arrangement is a simple design, most automotive engines are valve-in-head type.The valve-in-head engine has certain advantages.另一種氣門(mén)機(jī)構(gòu)的氣門(mén)是裝在氣缸體上，而不是裝在氣缸蓋上。在這種裝臵 25 中，凸輪軸直接裝在氣門(mén)挺桿下，并且不必有推桿或搖臂。雖然側(cè)臵氣門(mén)發(fā)動(dòng)機(jī)結(jié)構(gòu)設(shè)計(jì)簡(jiǎn)單，大多數(shù)汽車(chē)發(fā)動(dòng)機(jī)卻都是頂臵式氣門(mén)，因?yàn)轫斉Z式氣門(mén)發(fā)動(dòng)機(jī)確有優(yōu)點(diǎn)。

Cam and Camshaft A cam is a device that can change rotary motion into linear, or straight-line, motion.The cam has high spot, or lobe;a follower riding on the cam will move away from or toward the camshaft as the cam rotates.In the engine, cams on the camshaft cause the intake and exhaust valves to open.There is a cam on the camshaft for each valve, or two cams per cylinder.The camshaft is driven by gears, or by a chain, from the crankshaft.It turns at one-half crankshaft speed.In the four-cycle engine, every two revolutions of the crankshaft produce one revolution of the camshaft and one opening and closing.The cam lobes are so positioned on the camshaft as to cause the valves to open and close in the cylinders at the proper time with respect to the actions taking place in the cylinders.凸輪和凸輪軸

凸輪是能夠使旋轉(zhuǎn)運(yùn)動(dòng)轉(zhuǎn)變?yōu)榫€性或直線運(yùn)動(dòng)的裝臵。凸輪有一個(gè)頂點(diǎn)，或叫做凸輪凸角。當(dāng)凸輪轉(zhuǎn)動(dòng)時(shí)，凸輪上的從動(dòng)件也隨著凸輪軸來(lái)回移動(dòng)。在發(fā)動(dòng)機(jī)中，凸輪軸上的凸輪控制進(jìn)氣門(mén)和排氣門(mén)的開(kāi)啟和關(guān)閉。每個(gè)氣門(mén)有一凸輪，每一個(gè)氣缸就有兩個(gè)凸輪。凸輪軸由曲軸通過(guò)正時(shí)齒輪或鏈條來(lái)驅(qū)動(dòng)。凸輪軸的轉(zhuǎn)速為曲軸轉(zhuǎn)速的一半。在四行程發(fā)動(dòng)機(jī)中，曲軸每轉(zhuǎn)動(dòng)兩圈，凸輪軸轉(zhuǎn)動(dòng)一圈，使氣門(mén)開(kāi)啟和關(guān)閉一次。曲軸上凸輪凸角的位臵使氣門(mén)在恰當(dāng)?shù)臅r(shí)候開(kāi)關(guān)，以便與氣缸的工作順序相一致。

In addition, the camshaft has an eccentric to operate the fuel pump and a gear to drive the ignition distributor and oil pump.此外，凸輪軸還帶動(dòng)一個(gè)驅(qū)動(dòng)燃料泵的偏心輪和一個(gè)帶動(dòng)分電器和油泵的齒輪。

stem：柄，堵??；seat：氣門(mén)座；rest：安放；spring：彈簧；washer：墊圈；lifter：氣門(mén)挺桿；push：推桿；valve train：氣門(mén)組；cam rod：凸輪凸角；rocker arm：氣門(mén)搖桿臂；valve-in-head：頂臵式氣門(mén)；valve-in-block：到臵式氣門(mén)

9.Engine Fuel System 發(fā)動(dòng)機(jī)燃油系統(tǒng)

The fuel system has the job of supplying a combustible mixture of air and fuel to the engine.The fuel system must vary the proportions of air and fuel to suit different operating conditions.When the engine is cold, for example, then the mixture must be rich(have a high proportion of fuel).The reason for this is that the fuel does not vaporize rapidly at low temperatures.Therefore, extra fuel must be added to the mixture so that there will be enough vaporized fuel to form a combustible mixture.燃料供給系統(tǒng)的作用是向發(fā)動(dòng)機(jī)提供由空氣和燃料所組成的可燃混合氣。燃料系統(tǒng)必須改變空氣和燃料的比例以適應(yīng)不同的運(yùn)行狀態(tài)。例如，當(dāng)發(fā)動(dòng)機(jī)冷車(chē)時(shí)，就必須提供較濃的混合氣（具有較高的燃油比例）。這是因?yàn)樵诘蜏叵氯加筒荒苎杆贇饣?，因此，要在混合氣中額外增加燃油，這樣才有足夠氣化燃料形成可燃混合氣。

The fuel system consists of the fuel tank, fuel pump, fuel filter, carburetor, intake manifold, and fuel lines, or tubes, connecting the tank, pump, and carburetor.Some gasoline engines use a fuel-injection system;in this system, a fuel-injection pump replaces the carburetor.燃料系統(tǒng)包括汽油箱、汽油泵、汽油濾清器、化油器、進(jìn)氣歧管以及連接油箱、油泵和化油器的油管。有的汽油發(fā)動(dòng)機(jī)使用的是一套燃油噴射系統(tǒng)，在這一系統(tǒng)中，然油噴射泵取代了化油器。

The fuel tank, in which gasoline is stored, is normally located at the rear of the vehicle.It is made of sheet metal and is attached to the frame.汽油箱用來(lái)貯存汽油，通常安裝在汽車(chē)的后部。油箱由金屬板制成，固定在車(chē)架上。

A fuel pump delivers fuel from the tank to the carburetor.There are two general types of fuel pump, mechanical and electric.油泵把油箱中的燃油抽出送到化油器中。通用的油泵有兩種：機(jī)械泵和電子泵。The fuel system has filters and screens to prevent dire in the fuel from entering the fuel pump or carburetor.Dirt could, of course, prevent normal operation of these units and cause poor engine performance.燃料系統(tǒng)裝有濾清器和過(guò)濾網(wǎng)，防止燃油中的雜物進(jìn)入燃油泵或化油器。否則，污物會(huì)影響這些部件的正常運(yùn)轉(zhuǎn)，并引起發(fā)動(dòng)機(jī)運(yùn)轉(zhuǎn)不良

The carburetor is essentially a mixing device which mixes liquid gasoline with air.In this process, it throws a fine spray of gasoline into air passing through the carburetor on its way to the engine.The gasoline vaporizes and mixes with the air to form a highly combustible mixture.This mixture then enters the engine combustion chambers, where it is ignited.It burns, causing the engine to produce power.The mixture must be of varying degrees of richness to suit engine operating conditions.It must be rich(have a higher percentage of fuel)for starting, acceleration, and high-speed operation.And it should lean out(become less rich)for operation at intermediate speed with a warm engine.The carburetor has several different circuits, or passages, through which fuel and air-fuel mixture flow under different operating conditions to produce the varying richness of the air-fuel mixture.化油器實(shí)質(zhì)上是一個(gè)把液體燃油與空氣相混合的混合氣形成裝臵。在這一過(guò)程中，化油器把燃油以霧狀噴入流經(jīng)化油器的空氣中，然后進(jìn)入發(fā)動(dòng)機(jī)。霧化燃油和空氣形成高度易燃的混合氣?？扇蓟旌蠚膺M(jìn)入發(fā)動(dòng)機(jī)的燃燒室，并在那里被點(diǎn)燃?？扇蓟旌蠚馊紵拱l(fā)動(dòng)機(jī)產(chǎn)生動(dòng)力?；旌蠚獾臐舛缺壤梢愿淖?，以適應(yīng)發(fā)動(dòng)機(jī)的運(yùn)行狀況。汽車(chē)在啟動(dòng)、加速和高速行駛時(shí)，需要含燃油濃度較高的混合氣；熱狀態(tài)下的發(fā)動(dòng)機(jī)中速行駛時(shí)，混合氣含燃油濃度則可低一些?；推饔袔讉€(gè)不同的供油系統(tǒng)或通道，通過(guò)這些供油系統(tǒng)，在不同的行駛狀態(tài)下，可提供濃度不同的可燃混合氣。Words and Expressions combustible：易燃的；filter：過(guò)濾器；manifold：多種的；sheet：薄片；dirt：污垢；fine：細(xì)小的；spray：霧狀；richness：可燃成分高的混合燃料；throw into：噴入；lean out：（內(nèi)燃機(jī)的混合燃料等）可燃成分降低 28

10.Engine Lubricating System

發(fā)動(dòng)機(jī)潤(rùn)滑系統(tǒng)

There are a great many moving metal parts in the engine.These parts must be protected by lubricating oil so that there will be no actual metal-to-metal contact.The moving parts, in effect, float on films of oil.發(fā)動(dòng)機(jī)中有大量的運(yùn)動(dòng)的金屬零件。要保護(hù)這些零件就必須進(jìn)行潤(rùn)滑，這樣可以避免金屬零件之間的直接接觸。實(shí)際上，在運(yùn)動(dòng)零件的表面總是覆蓋著一層油膜。

Two types of lubricating systems have been used on four-cycle automotive engines, splash and combination splash and pressure feed.四行程發(fā)動(dòng)機(jī)使用兩種潤(rùn)滑系統(tǒng)：飛濺式潤(rùn)滑和飛濺壓力結(jié)合送油式潤(rùn)滑。In the splash lubricating system, oil is splashed up from the oil pan or oil trays in the lower part of the crankcase.The oil is thrown upward as droplets or fine mist and provides adequate lubrication to valve mechanisms, piston pins, cylinder walls, and piston rings.在飛濺潤(rùn)滑系統(tǒng)中，油從機(jī)體下部的油盤(pán)活油底殼中飛濺上來(lái)。飛濺上來(lái)的油形成油滴或油霧，使氣門(mén)機(jī)構(gòu)、活塞銷(xiāo)、氣缸壁和活塞環(huán)得到充分的潤(rùn)滑。

In the combination splash and pressure feed lubricating system, an oil pump takes oil from the oil pan and forces it through holes drilled in the engine block and crankshaft.This oil thereby reaches the various bearings that support rotating shafts and the different moving parts in the engine.It covers the surfaces of the moving parts in the engine.It covers the surfaces of the moving parts to prevent metal-to-metal contact and undue water of the parts.在飛濺壓力結(jié)合送油潤(rùn)滑系統(tǒng)中，油泵從油盤(pán)中把油抽上來(lái)并壓入發(fā)動(dòng)機(jī)機(jī)體上和曲軸上的油道，被輸送到發(fā)動(dòng)機(jī)的曲軸和各種運(yùn)動(dòng)零件的每個(gè)軸承上。潤(rùn)滑油在運(yùn)動(dòng)零件表面形成油膜，以防止金屬零件表面直接接觸以及零件的過(guò)度磨損。

In this system, cylinder walls are lubricated by splashing oil thrown off from the connecting-rod bearing.The lubricating oil circulating through the engine to all moving parts requiring lubrication performs other jobs.在這一系統(tǒng)中，氣缸壁是由連桿軸承運(yùn)動(dòng)飛濺起來(lái)的油進(jìn)行潤(rùn)滑的。潤(rùn)滑油在發(fā)動(dòng)機(jī)的所有活動(dòng)部件之間循環(huán)流動(dòng)，其作用為：

1)Lubricate moving parts to minimize wear.2)Lubricate moving parts to minimize power loss from friction.3)Remove heat from engine parts by acting as a cooling agent.4)Absorb shocks between bearings and other engine parts, thus reducing engine noise and extending engine life.5)Form a good seal between piston rings and cylinder walls.6)Act as a cleaning agent, washing the working surfaces free of chemical deposits, dust and dirt to protect them from corrosion.1.潤(rùn)滑運(yùn)動(dòng)零件，減少磨損。

2.潤(rùn)滑運(yùn)動(dòng)零件，減少因摩擦引起的功率損耗。3.起冷卻劑作用，帶走發(fā)動(dòng)機(jī)零件產(chǎn)生的熱量。

4.吸收軸承和其它發(fā)動(dòng)機(jī)零件之間產(chǎn)生的沖擊力，減少發(fā)動(dòng)機(jī)的噪音，并延長(zhǎng)其壽命。

5.在活塞環(huán)和氣缸壁之間形成良好的密封。

6.起清潔劑作用，沖洗運(yùn)動(dòng)零件表面的化學(xué)雜質(zhì)，灰塵和污物，以避免部件受到腐蝕。

A satisfactory engine lubricating oil must have certain characteristics, or properties.It must have proper viscosity(body and fluidity)and must resist oxidation, carbon formation, corrosion, rust, extreme pressure, and foaming.Also, it must act as a good cleaning agent, must pour at low temperatures, and must have good viscosity at extremes of high and low temperature.理想的發(fā)動(dòng)機(jī)潤(rùn)滑油必須具有某些特性：必須具有一定的粘性（粘稠度和流 動(dòng)性），并且必須具有抗氧化、防止碳膜生成、防腐、防銹、抗極壓和防泡沫等作用，潤(rùn)滑油必須具有良好清潔作用和良好的低溫流動(dòng)性，以及在高溫和低溫時(shí)都具有良好的粘性。

Any mineral oil, by itself, does not have all these properties.Lubricating-oil manufacturers therefore put a number of additives into the oil during the manufacturing process.An oil for severe service may have many additives, as follows:(1)usually a viscosity-index improver;(2)pour-point depressants;(3)oxidation inhibitors;(4)corrosion inhibitors;(5)rust inhibitors;(6)foam inhibitors;(7)detergent-dispersants;(8)extreme-pressure agents.任何礦物油自身都不具備所有這些特性。因此，潤(rùn)滑油廠家在制造潤(rùn)滑油的過(guò)程中，加入了許多添加劑。高級(jí)潤(rùn)滑油中可能加入以下這些添加劑：（1）常常加入黏度指數(shù)添加劑；（2）抗凝劑；（3）抗氧劑；（4）防腐劑；（5）防銹劑；（6）抗泡劑；（7）凈化分散劑；（8）極壓劑。

Words and Expressions agent：（化學(xué)）劑；oxidation：氧化；additive：添加的，添加物；improver：促進(jìn)劑；depressant：抑制劑（添加劑）；inhibitor：抑制劑，防腐劑；detergent：凈化劑，去垢劑；dispersant：分散劑；splash lubricating：飛濺式潤(rùn)滑；combination splash and pressure feed lubricating：飛濺壓力結(jié)合式潤(rùn)滑；valve：氣門(mén)機(jī)構(gòu)；cleaning agent：清潔劑；chemical deposits：化學(xué)沉淀。31

11.Engine Cooling System

發(fā)動(dòng)機(jī)冷卻系統(tǒng)

The purpose of the cooling system is to keep the engine at its most efficient operating temperature at all engine speeds and all driving conditions.冷卻系統(tǒng)的作用是使發(fā)動(dòng)機(jī)在各種轉(zhuǎn)速和各種行駛狀態(tài)下都能有效地控制溫度。

A great deal of heat is produced in the engine by the burning of the air-fuel mixture.Some of this heat escapes from the engine through the exhaust gases(the host gases left after the gasoline is burned).But enough remains in the engine to cause serious trouble unless removed by some other means.The cooling system takes care of this additional heat.混合氣的燃燒在發(fā)動(dòng)機(jī)中產(chǎn)生大量的熱，其中部分熱量通過(guò)廢氣被排出。但是，殘留在發(fā)動(dòng)機(jī)中的余熱仍足以使發(fā)動(dòng)機(jī)受到嚴(yán)重?fù)p壞，除非用其它的方法排除這些余熱。冷卻系統(tǒng)就是專門(mén)用來(lái)消除余熱的。

The cooling system is built into the engine.There are hollow spaces around each engine cylinder and combustion chamber.These hollow spaces are called water jackets, since they are filled with water.When the engine is running, the water takes heat from the engine, becoming hot in the process.A water pump pumps the hot water from the engine water jackets into the radiator.The radiator has two sets of passages.One set carries water.The other set carries air(pulled through by car motion and engine fan).As the hot water passes through, it gives up its heat to the air passing through.The cooled water then reenters the engine, where it can pick up more heat.In operation, water continuously circulates between the engine and radiator, carrying heat from the engine to the radiator.By this means, excessive engine temperatures are prevented.冷卻系統(tǒng)就設(shè)臵在發(fā)動(dòng)機(jī)中。在每個(gè)氣缸體和燃燒室周?chē)剂粲锌涨弧＿@些空腔裝滿了水，因此稱之為水套。在發(fā)動(dòng)機(jī)運(yùn)行過(guò)程中水被加熱，并以水循環(huán)方式把熱量從發(fā)動(dòng)機(jī)中帶走。水泵從發(fā)動(dòng)機(jī)水套中把熱水抽到散熱器中。散熱器有兩條通道：一條是水道，另一條是氣道（空氣是通過(guò)汽車(chē)行駛和發(fā)動(dòng)機(jī)的風(fēng)扇抽

入的）。當(dāng)熱水流過(guò)水道時(shí)，氣道中流通的空氣使熱水冷卻。冷卻后的水又重新進(jìn)入發(fā)動(dòng)機(jī)，再把發(fā)動(dòng)機(jī)中的熱量傳導(dǎo)出去。在這一過(guò)程中，水不斷地在發(fā)動(dòng)機(jī)與散熱器之間循環(huán)，水?dāng)y帶著熱量從發(fā)動(dòng)機(jī)流到散熱器再散發(fā)出去。通過(guò)這個(gè)方法可避免發(fā)動(dòng)機(jī)溫度過(guò)高。

Two general types of cooling systems are used, air cooling and liquid cooling.Most automotive engines now employ liquid cooling.The liquid cooling system consists of water pumps, water jackets, engine fan, radiator, and so on.The water pump, driven by a belt from the engine crankshaft, circulates the cooling liquid between the radiator and engine water jackets.The cooling liquid is water.Antifreeze compounds are added to the water during the winter.The water jacket is cast into the cylinder blocks and heads.The engine fan is usually mounted on the water pump shaft and is driven by the same belt that drives the pump and the generator.The purpose of the fan is to provide a powerful draft of air through the radiator.The radiator is a device for holding a large volume of water in close contact with a large volume of air so that heat will transfer from the water to the air.The radiator core is divided into two separate and intricate compartments;water passes through one, and air passes through the other.通常使用的冷卻系統(tǒng)有兩種形式：空氣冷卻系和液體冷卻系?，F(xiàn)在大多數(shù)汽車(chē)發(fā)動(dòng)機(jī)都采用液體冷卻系。液體冷卻系由水泵、水套、發(fā)動(dòng)機(jī)風(fēng)扇、散熱器等組成。水泵由發(fā)動(dòng)機(jī)曲軸上的皮帶驅(qū)動(dòng)，使冷卻液在散熱器與發(fā)動(dòng)機(jī)水套之間循環(huán)流動(dòng)。冷卻液是水。冬季在水中需加入防凍劑。水套被鑄入氣缸體和氣缸蓋內(nèi)部。發(fā)動(dòng)機(jī)風(fēng)扇通常安裝在水泵軸上，由驅(qū)動(dòng)水泵和發(fā)電機(jī)的同一條皮帶驅(qū)動(dòng)。風(fēng)扇的作用是向散熱器提供強(qiáng)大的空氣流，與大量空氣密切接觸的散熱器內(nèi)可以容納大量的水，這樣熱量可以通過(guò)水散發(fā)到空氣中。散熱器芯為分離和間隔交錯(cuò)的兩部分。冷卻水在其中一部分流過(guò)，空氣在另一部分中通過(guò)。Words and Expressions radiator：散熱器，水箱；antifreeze：防凍劑；compound：混合物；draught：氣流；compartment：間隔。33

14.Engine Ignition System

發(fā)動(dòng)機(jī)點(diǎn)火系統(tǒng)

The ignition system is part of the electric system of the automobile.Its purpose is to produce high-voltage surges(up to 20,000 volts)and to deliver them to the combustion chambers in the engine.These high-voltage surges then cause electric sparks in the combustion chambers.The sparks ignite, or set fire to, the air-fuel mixture in the combustion chambers so that it burns and causes the engine to operate.點(diǎn)火系統(tǒng)是汽車(chē)電氣系統(tǒng)的一部分。其作用是產(chǎn)生高達(dá)2萬(wàn)伏的高壓電脈沖，并且將其輸送到發(fā)動(dòng)機(jī)的燃燒室。高壓電脈沖在燃燒室中形成點(diǎn)火花，引燃燃燒室中的可燃混合氣，使發(fā)動(dòng)機(jī)運(yùn)轉(zhuǎn)。

The ignition system consists of three basic parts: the ignition distributor, the ignition coil, and the spark plug, together with the connecting wires.When the engine is turning, the ignition coil is repeated connected to and disconnected from the battery.Every time the coil is connected, it becomes loaded with electrical energy.Then, when it is disconnected, the ―load‖ of electrical energy is released in a high-voltage surge.This surge flows through the wiring to the spark plug in the engine cylinder that is ready to fire.You must understand that all this takes place very rapidly.At high speed, the whole series of events happens in less than one three-hundredth o a second.That is, there will be as many as 300 of these events every second that the engine is running at high speed.點(diǎn)火系統(tǒng)包括三個(gè)基本部分：點(diǎn)火分電器、點(diǎn)火線圈和火花塞，以及起連接作用的導(dǎo)線。當(dāng)發(fā)動(dòng)機(jī)轉(zhuǎn)動(dòng)時(shí)，點(diǎn)火線圈與蓄電池之間不斷地連接和斷開(kāi)。每當(dāng)線圈與蓄電池接通時(shí)，就會(huì)充載電荷，然而當(dāng)線圈與蓄電池?cái)嚅_(kāi)時(shí)，電荷以高壓脈沖的方式釋放出來(lái)，通過(guò)導(dǎo)線把高壓電脈沖輸送到待點(diǎn)火的發(fā)動(dòng)機(jī)氣缸上的火花塞上。你必須理解這一切發(fā)生得極其迅速。全部一系列動(dòng)作以極高的速度發(fā)生在短短三百分之一秒內(nèi)。也就是說(shuō)，在發(fā)動(dòng)機(jī)高速運(yùn)轉(zhuǎn)時(shí)，這樣的動(dòng)作每秒鐘要發(fā)生三百次。

Some systems use transistors to reduce the load on the distributor contact points.Other systems do not have contact points but use instead a combination of transistors

and a magnetic pick-up in the distributor.有些點(diǎn)火系統(tǒng)使用晶體管來(lái)減少分電器觸點(diǎn)的負(fù)荷。這種點(diǎn)火系統(tǒng)沒(méi)有觸點(diǎn)，而是在分電器中使用晶體管與磁傳感器。

The ignition distributor has two jobs.First, it closes and opens the circuit between the battery and ignition coil.The distributor’s second job is to distribute each high voltage surge to the correct spark plug at the correct instant by means of the distributor rotor and cap and secondary wiring.點(diǎn)火系統(tǒng)的分電器有兩個(gè)作用。首先，負(fù)責(zé)接通和關(guān)閉蓄電池和點(diǎn)火線圈之間的電路。分電器的第二個(gè)作用是通過(guò)分火頭、旁電極和輔助線路，將高壓電流準(zhǔn)時(shí)地分配給相應(yīng)的火花塞。

There are two basic types of distributor:(1)the type using contact points to close and open the coil primary circuit;(2)the type using a magnetic pick-up and a transistor control unit to interrupt the current flow of the coil primary circuit.分電器有兩種基本形式：一種是使用觸點(diǎn)關(guān)閉和接通初級(jí)線圈的電流，另一種使用磁傳感器和晶體管控制裝臵來(lái)切斷初級(jí)線圈的電流。

Words and Expressions voltage：電壓，伏特?cái)?shù)；surge：沖擊；disconnect：分離，斷開(kāi)；the electric system：電氣系統(tǒng)；ignition distributor：點(diǎn)火分電器；ignition coil：點(diǎn)火線圈；spark plug：火花塞；high-voltage surge：高壓電脈沖；magnetic pick-up：電磁傳感器；contact point：觸點(diǎn)；the coil primary circuit：初級(jí)線圈；transistor control unit：晶體管控制裝臵；distributor rotor and cap：分電器分火頭和旁電極；secondary wiring：次級(jí)線圈，輔助線路。35

15.Engine Starting System

發(fā)動(dòng)機(jī)起動(dòng)系統(tǒng)

Automobile engines are not self-starts.In order to start them, the engine crankshaft must be turned over by some outside means so as to(a)admit air-fuel mixture to the cylinder, and(b)cause the mixture to fire.汽車(chē)發(fā)動(dòng)機(jī)是不能自行啟動(dòng)的。為了啟動(dòng)發(fā)動(dòng)機(jī)，發(fā)動(dòng)機(jī)曲軸必須借助外界的手段轉(zhuǎn)動(dòng)起來(lái)，這樣：（1）使可燃混合氣進(jìn)入氣缸，（2）是可燃混合氣點(diǎn)火。

In the case of automobile engines, the mixture in the cylinder, after being compressed, must be not enough to ignite.This requires that the engine be turned over with sufficient speed.If the engine is turned over too slowly, the unavoidable small leaks past the piston rings and also through the intake the exhaust valves of four-cycle engines will permit a substantial part of the fuel-air mixture to escape during the compression stroke.Also, the heat loss from the compressed air to the cylinder walls will be greater at low speed because of the longer exposure.The escape of air and the loss of heat both result in a lower temperature at the end of compression.Therefore, there is a minimum speed which the engine must attain before ignition will occur and the engine will begin firing.The starting speed depends upon the type and size of the engine, its condition, and the temperature of the air entering the engine.對(duì)于汽車(chē)發(fā)動(dòng)機(jī)來(lái)說(shuō)，氣缸中的可燃混合氣被壓縮后，必須有足夠的熱量才能被點(diǎn)燃。這就要求發(fā)動(dòng)機(jī)達(dá)到足夠高的轉(zhuǎn)速。如果發(fā)動(dòng)機(jī)轉(zhuǎn)速太慢，四行程發(fā)動(dòng)機(jī)的活塞環(huán)和進(jìn)排氣門(mén)就不可避免地有泄漏現(xiàn)象，這會(huì)使大量的可燃混合氣在壓縮行程期間泄漏掉。此外，發(fā)動(dòng)機(jī)在低速時(shí)，由于接觸時(shí)間較長(zhǎng)，壓縮氣體傳給氣缸壁的熱量較大。在壓縮過(guò)程結(jié)束，溫度較低的情況下，會(huì)產(chǎn)生漏氣和熱損失兩種現(xiàn)象。所以，發(fā)動(dòng)機(jī)在引燃和開(kāi)始點(diǎn)火前，必須達(dá)到一個(gè)最低轉(zhuǎn)速。啟動(dòng)轉(zhuǎn)速取決于發(fā)動(dòng)機(jī)的型號(hào)、大小和狀態(tài)以及進(jìn)入發(fā)動(dòng)機(jī)的空氣的溫度。

The starting system contains a cranking, or starting, motor, and other accessories.起動(dòng)系統(tǒng)包括起動(dòng)機(jī)和其它附件。

The starting motor electrically cranks the engine for starting.It is a special 36 direct-current motor operating on battery voltage and is mounted on the engine flywheel house.The starter changes the electrical current into the mechanical energy to push the crank-shaft round.By means of this, the engine can be started.The cranking motor consists of the commutator end head, holding the brushes;the field frame, into which the field windings are assembled around pole shoes;the drive housing, which houses the drive assembly the supports the motor on the engine flywheel housing;the armature;and the drive assembly.Some cranking motors also have a solenoid that operates the shift lever.起動(dòng)電機(jī)用電能來(lái)啟動(dòng)發(fā)動(dòng)機(jī)。起動(dòng)電機(jī)是以蓄電池為動(dòng)力來(lái)源的直流電機(jī)，它安裝在發(fā)動(dòng)機(jī)的飛輪殼上。起動(dòng)電機(jī)把電流轉(zhuǎn)換為機(jī)械能，驅(qū)動(dòng)曲軸轉(zhuǎn)動(dòng)，并帶動(dòng)發(fā)動(dòng)機(jī)運(yùn)轉(zhuǎn)。起動(dòng)電機(jī)由固定電刷的換向器頭、磁場(chǎng)框架、傳動(dòng)箱、電樞以及傳動(dòng)總成等組成，在磁場(chǎng)框架中，勵(lì)磁線圈內(nèi)套著電樞；傳動(dòng)箱內(nèi)裝有傳動(dòng)總成，并且支承固定在發(fā)動(dòng)機(jī)飛輪殼上的電動(dòng)機(jī)。有些起動(dòng)電機(jī)還有一線圈來(lái)帶動(dòng)操縱桿。

Cranking-motor controls have varied from a simple foot-operated pedal to automatic devices that close the cranking-motor circuit when the accelerator pedal is depressed.控制起動(dòng)電機(jī)的方式已從一個(gè)簡(jiǎn)單的腳踏板改為壓下加速踏板即可自動(dòng)接通起動(dòng)電機(jī)電路的自動(dòng)裝臵。

The present system that has been almost universally adopted for passenger cars and many other vehicles has starting contacts in the ignition switch.When the ignition key is turned against spring pressure past the ON position to START, the starting contacts close.This connects the cranking-motor solenoid or magnetic switch to the battery.After the engine starts and the ignition key is released, spring pressure returns it to the ON position.The starting motor should not be operated more than 5 seconds during each starting operating, for the sake of recovering the energy of battery.It will not be allowed to start it again until it’s stopped for fifteen second.轎車(chē)和其它許多類(lèi)型的車(chē)輛已普遍采用點(diǎn)火開(kāi)關(guān)裝臵。起動(dòng)接觸器裝在點(diǎn)火開(kāi)關(guān)上。轉(zhuǎn)動(dòng)點(diǎn)火鑰匙，彈簧的壓力使“開(kāi)啟”位臵變?yōu)椤皢?dòng)”位臵，啟動(dòng)接 37 觸器閉合，使得啟動(dòng)電機(jī)線圈或磁性開(kāi)關(guān)與電池接通。發(fā)動(dòng)機(jī)啟動(dòng)以后，點(diǎn)火鑰匙回轉(zhuǎn)，在彈簧的壓力下，恢復(fù)到“開(kāi)啟”位臵。起動(dòng)電機(jī)每次啟動(dòng)過(guò)程的時(shí)間限定在5秒鐘以內(nèi)，以便使電池的能量及時(shí)得到補(bǔ)充。15秒后方可再次啟動(dòng)。

Words and Expressions accessory：附件；commutator：換向器；brush：電刷；armature：電樞；solenoid：螺絲管；cranking motor：起動(dòng)電機(jī)；foot-operated pedal：腳踏板；for the sake of：為了…起見(jiàn)；direct-current motor：直流電機(jī)；flywheel house：飛輪殼；commutator end head：換向器端頭；the field frame：磁場(chǎng)框架；field windings：勵(lì)磁線圈；pole shoes：電樞；drive housing：傳動(dòng)箱；the drive assembly：傳動(dòng)總成；shift lever：換檔操縱桿；accelerator pedal：加速器踏板；starting contact：?jiǎn)?dòng)觸點(diǎn)器。38

14.Locomotives 1.Steam Locomotive 1.蒸汽機(jī)車(chē)

The speed of railways, which transformed life in the nineteenth century, is linked inextricably with the steam locomotive.To its devotees the steam locomotive was one of the most romantic and beautiful machines ever built.It first appeared in 1804 in a simple version invented by an Englishman Richard Trevithick.19世紀(jì)改變了人們生活的鐵路的飛速發(fā)展與蒸汽機(jī)車(chē)密不可分。對(duì)其熱愛(ài)者來(lái)說(shuō)，蒸汽機(jī)車(chē)是有史以來(lái)建造的最具羅曼蒂克最漂亮的機(jī)器。最早的蒸汽機(jī)車(chē)出現(xiàn)于1804年，是由英國(guó)人Richard Trevithick發(fā)明的一個(gè)簡(jiǎn)單版本。

The first steam locomotives to do useful work were ordered and used by coal mines in northeast England in 1813-20.in 1825 a public railway was opened between the English towns of Stockton and Darlington.It had been planned for horse traction, but George Stephenson(1781-1848), a leading builder of colliery locomotives, persuaded the directors to operate a steam locomotive hauling trains heavier than horses could manage.The success of this line led to the much bigger and more important railway between Liverpool and Manchester.It was opened in 1830 after bitter opposition from landlords, coachmen, canal bargees and the large sector of the population that abhorred any change and considered smoke-spouting locomotives to be engines of Satan.Against spirited competition, Stephenson’s Rocket was chosen to provide the motive power.It was small and light enough to run on only four wheel without breaking the flimsy iron track.Thanks to steady improvements in manufacturing, it became possible to make boilers stronger, cylinders and pistons more accurate and better fitting, and the whole locomotive capable of developing more power at higher speeds.將蒸汽機(jī)車(chē)最早用于作有用功是在1813-1820年英格蘭東北部的煤礦上。

1825年，英國(guó)的Stockton 鎮(zhèn)和Darlington鎮(zhèn)之間開(kāi)通了一條公共鐵路。這條路本來(lái)的設(shè)計(jì)是使用馬匹來(lái)牽引，但是一位煤礦機(jī)車(chē)的主要建造者George Stephenson(1781-1848)說(shuō)服了領(lǐng)導(dǎo)者采用蒸汽機(jī)車(chē)來(lái)牽引列車(chē)，這比馬能牽引的要重的多。這條線路的成功導(dǎo)致了利物浦和曼徹斯特之間的更大更重要的鐵路的問(wèn)世。這條鐵路開(kāi)通于1830年，之前受到了來(lái)自地主、馬車(chē)夫、運(yùn)河船員和那些憎恨任何變化并將噴出煙霧的機(jī)車(chē)視作魔鬼機(jī)器的大范圍人口的強(qiáng)烈反對(duì)。經(jīng)過(guò)激烈的競(jìng)爭(zhēng)，斯蒂芬孫的Rocket被選作動(dòng)力的提供者。該機(jī)車(chē)又小又輕，僅有四個(gè)輪子，這樣才不至于破壞脆弱的鐵軌。由于制造方面的穩(wěn)步發(fā)展，逐漸變得可以制造更堅(jiān)固的鍋爐，氣缸和活塞的制造也更精確、相配更好，機(jī)車(chē)整體也有能力在更高的速度下產(chǎn)生更大的功率。

For a century steam locomotives provided nearly all the traction for the world’s railways.There were no dramatic technical advances but size, power and speed grew constantly.In Europe many rail systems used excellent track, capable of bearing 100 tonne locomotives running at up to 160km/h(100mph).But in the United States in early days, and in most other young, developing countries, track was lighter, and often badly laid by men racing to complete more miles each day.This called for more wheels to spread the load.Speeds were limited and seldom exceeded 80km/h(500mph), apart from one or two short record-setting runs.在整個(gè)世紀(jì)內(nèi)，對(duì)世界上的鐵路而言，其牽引幾乎都由蒸汽機(jī)車(chē)提供。除了體積、功率和速度不斷提升之外沒(méi)有什么大的變化。在歐洲，許多鐵路系統(tǒng)都采用非常優(yōu)良的鐵軌，可以承載100噸的機(jī)車(chē)以高達(dá)160千米/小時(shí)（每小時(shí)100英里）的速度運(yùn)行。但是在早期的美國(guó)以及大多數(shù)年輕的發(fā)展中國(guó)家，鐵軌的承載能力較小，而且人們通常為了比賽每天完成更多英里的鋪設(shè)這些鐵軌通常鋪得很差。這就需要更多的輪子來(lái)分散負(fù)載。車(chē)速因此受到限制，除了極個(gè)別短暫的破紀(jì)錄運(yùn)行之外，很少有超過(guò)80千米/小時(shí)（每小時(shí)50英里）的。

The steam locomotive has reached its zenith by the 1930s.European ―steamers‖ were clean, splendidly painted in the livery of their operating companies and, when designed for express passenger haulage, often capable of reaching 160km/h(100mph).40 American locomotives tended to be more utilitarian.Demands for greater power led to increases in size until they became the biggest land vehicles in history.蒸汽機(jī)車(chē)的發(fā)展于20世紀(jì)30年代之前達(dá)到了頂峰。歐洲的蒸汽機(jī)車(chē)整潔華麗，描繪著所在公司的圖案，在被設(shè)計(jì)用于快速客運(yùn)時(shí)速度常?？蛇_(dá)到160千米/小時(shí)（每小時(shí)100英里）。美國(guó)機(jī)車(chē)則趨向于更功利化。對(duì)更大功率的要求導(dǎo)致了體積的增長(zhǎng)直到它們變成了有史以來(lái)最大的陸上運(yùn)輸工具。2.Electric Locomotive 2.電力機(jī)車(chē)

The first rival to steam came in the form of the direct-current electric motor, adopted in cities(especially in underground railways), to avoid smoke pollution.The first electric train ran at an exhibition in Berlin in 1879.Soon countries such as Switzerland and Norway found that it was cheaper, with the development of hydroelectric power, to generate electricity than to burn brown coal or wood, and their networks became all electric.蒸汽機(jī)車(chē)最早的對(duì)手是主要用于城市中（尤其是地下鐵路），為了避免煙氣污染的直流電力馬達(dá)機(jī)車(chē)。最早的電力火車(chē)是1879年在柏林作為展示運(yùn)行的。很快一些國(guó)家諸如瑞士和挪威發(fā)現(xiàn)隨著水力發(fā)電的發(fā)展，發(fā)電要比燃燒褐煤或木材要便宜，因此它們的鐵路網(wǎng)絡(luò)很快全都變成了電力的。

Today the electric motor with its linear form under development, is regarded as the best from of traction for railways but the huge capital costs impede its introduction except on the busiest routes.As long ago as 1955, French Railways demonstrated that electric trains of conventional type could run at more than 320km/h(200mph), but average speeds of public trains have risen only slowly.The Japanese New Tokaido line achieved a sudden jump in speed because the line was laid for high speed.Even so , track and trains need constant maintenance.41 現(xiàn)在電力馬達(dá)及由其發(fā)展出的一次形式，以被認(rèn)為是鐵路牽引最好的形式，但是除了在一些繁忙的線路上，它的引入因?yàn)榫薮蟮耐顿Y而受到了限制。早在1955年，法國(guó)鐵路公司就證明常規(guī)式的電氣化列車(chē)可在320千米/小時(shí)（每小時(shí)200英里）以上車(chē)速下運(yùn)行，但普通列車(chē)的平均車(chē)速仍增長(zhǎng)緩慢。而在日本新干線上，由于線路適用于高速，因此車(chē)速得到了迅猛提高。盡管如此，軌道和列車(chē)都需要定期的維修。3.Diesel Locomotive 3.內(nèi)燃機(jī)車(chē)

About 1920, the first diesel locomotives and railcars came into general use, powered by compression-ignition oil engines developed by the German Rudolph Diesel(1858-1913)。Though often noisy, diesel engines pick up speed faster and convert 25 to 45 per cent of their fuel energy into useful haulage, whereas the fuel efficiency of steam traction seldom exceeded eight per cent.Despite greater capital cost, diesel locomotives gradually ousted steam from 1935 onwards, until today steam engines are confined to a shrinking number of railways in Africa and Asia and a few local lines elsewhere.Diesels can be started and stopped easily, burn no fuel when not working, and can run at close to maximum power for hours at a time with no strain on either machines or crew.Many diesel locomotives run more than 160 000 km(100 000 miles)a year and modern examples are highly reliable, versatile and relatively efficient, as well as being fast.大約在1920年，最早的內(nèi)燃機(jī)車(chē)和鐵路車(chē)輛投入廣泛的運(yùn)行，其動(dòng)力由德國(guó)人魯?shù)婪蚋倪M(jìn)的壓縮點(diǎn)火的燃油發(fā)動(dòng)機(jī)提供。盡管通常噪聲很大，但是內(nèi)燃機(jī)車(chē)加速較快，而且可以將燃料能量的25%到45%轉(zhuǎn)變成有用的牽引力，而蒸汽機(jī)車(chē)的燃料轉(zhuǎn)化效率則很少有超過(guò)8%的。盡管內(nèi)燃機(jī)車(chē)投資較大，但還是從1935年起逐步取代了蒸汽機(jī)車(chē)，到目前蒸汽機(jī)車(chē)的應(yīng)用已越來(lái)越少，只限于非洲、亞洲的部分鐵路和其他地方的一些市郊線上。內(nèi)燃機(jī)車(chē)的啟動(dòng)和停車(chē)都很容易，在不工作時(shí)不會(huì)消耗燃料，而且有時(shí)還可以數(shù)小時(shí)保持接近最大功率運(yùn)行而不會(huì)對(duì)

機(jī)器和乘務(wù)人員造成損傷。許多內(nèi)燃機(jī)車(chē)每年可以運(yùn)行160000千米（100000英里）以上，現(xiàn)代的內(nèi)燃機(jī)車(chē)不僅高速，而且有高度的可靠性、適用性和較高的效率。

Only in the smallest sizes does the diesel engine drive the wheels through a mechanical gearbox, as on a lorry.Generally the two are linked hydraulically or electrically.Hydraulic transmissions are arrangements of turbines linked by oil under high pressure, and they can transmit smoothly 2 000 horsepower with any ratio between input and output speeds.In the diesel-electric locomotives the engine drives a generator or alternator.This is used to supply current to traction motors similar to those of electric locomotives.除了像載重卡車(chē)中的這種小型柴油機(jī)是通過(guò)機(jī)械變速箱來(lái)驅(qū)動(dòng)車(chē)輪的以外，一般情況下柴油機(jī)與車(chē)輪之間都是利用液壓或電力來(lái)傳動(dòng)的。液壓傳動(dòng)通過(guò)設(shè)臵由高壓油驅(qū)動(dòng)的渦輪來(lái)實(shí)現(xiàn)，液壓傳動(dòng)可以在輸入與輸出速度之間為任意傳動(dòng)比時(shí)平穩(wěn)的傳輸2000馬力的功率。在柴油發(fā)電機(jī)機(jī)車(chē)中，用發(fā)動(dòng)機(jī)來(lái)驅(qū)動(dòng)發(fā)電機(jī)或交流發(fā)電機(jī)。同電力機(jī)車(chē)中相似，這被用來(lái)向牽引馬達(dá)供給電流。

15.Diesel Traction

內(nèi)燃牽引

We have now to consider the characteristics of the diesel engine, and the way in which it is used in railway traction.As we saw earlier, in an engine of this type the high temperature needed to ignite the fuel is produced by the piston, which compresses the air in the cylinder to between 650 and 850 lb.per sq.in., raising its temperature to between 1,500 and 1,800 degrees Fahr.When the maximum compression has been reached, the oil, at a pressure of from 2,000 to as much as 5,000 lb.per sq.in., is injected in the form of a finely divided spray, and ignites with explosive force, diving the piston backwards under a pressure of 850 to 1,000 lb.per sq.in..Injection continues for long enough during the piston stroke to ensure that combustion and the pressure on the piston correspondingly even.我們現(xiàn)在考慮一下柴油機(jī)的特性及其用于鐵路牽引的方式是很有必要的。正如我們?cè)谇懊婵吹降?，這類(lèi)發(fā)動(dòng)機(jī)燃油點(diǎn)火所需要的高溫是由活塞產(chǎn)生的，活塞在氣缸內(nèi)將空氣壓縮，使壓力達(dá)到650磅/平方英寸到850磅/平方英寸，溫度升高到華氏1500度到1800度。當(dāng)壓力達(dá)到最大限度時(shí)，燃油的壓力達(dá)到2000磅/平方英寸甚至高達(dá)5000磅/平方英寸，呈細(xì)霧狀噴射進(jìn)氣缸并點(diǎn)火，產(chǎn)生爆炸力，以850-1000磅/平方英寸的壓力推動(dòng)活塞向下運(yùn)行。在這個(gè)活塞沖程內(nèi)，燃油繼續(xù)噴射，以保證燃燒繼續(xù)進(jìn)行并使對(duì)活塞的壓力相應(yīng)地均勻。

Many modern diesel engines are ―supercharged‖ by an increase in the pressure of the air before it is passed into the cylinders.The most common application is by the turbo-supercharger, in which the exhaust gases from the cylinder drive a gas turbine coupled to an air-compressor.The latter fills the cylinder with air at from 147 to 22 lb.per sq.in.above atmospheric pressure, and this high pressure encourages a proportionately greater consumption of fuel, so boosting the power output by as much as 50 per cent.一些現(xiàn)代的柴油機(jī)是增壓的，在空氣進(jìn)入氣缸之前就增加其壓力。最常采用的是渦輪增壓器，由氣缸排出的廢氣驅(qū)動(dòng)燃?xì)廨啓C(jī)，并帶動(dòng)連接在一起的空氣壓縮機(jī)。由空氣壓縮機(jī)以超過(guò)大氣壓17-22磅/平方英寸的壓力將空氣壓入氣缸。44 這樣高的壓強(qiáng)，促使燃油消耗量相應(yīng)地增多，因而提高柴油機(jī)的輸出功率，差不多提高50%。

In Great Britain the type of diesel engine in most common use is the four-stoke.The first stoke of the piston compresses the air;just before the end of it the fuel is injected and combustion begins, continuing during the return stroke;the third stroke is the one during which the cylinder is ―scavenged‖ of its spent gases;and in the fourth stroke-that is, the second return stroke-the exhaust port closes, and the inlet valve is opened to admit the air for the next compression stroke.在英國(guó)最常使用的柴油機(jī)是四沖程的。第一活塞沖程是壓縮空氣：正好在此沖程結(jié)束之前進(jìn)行噴油和開(kāi)始燃燒，并在活塞回程中（即第二沖程）繼續(xù)進(jìn)行；第三沖程排出氣缸內(nèi)已用過(guò)的廢氣；在第四沖程中，活塞第二次回程，排氣孔關(guān)閉，進(jìn)氣閥打開(kāi)以吸入空氣，為下個(gè)壓縮沖程做準(zhǔn)備。

It is during one stroke only out of the four, the second, that the engine develops its power, and this is why the diesel engine requires a number of cylinders, from four in a small shunter to sixteen or more in a main unit of high power, with their cranks set at angles which divide up the circle into a corresponding number of equal parts, so ensuring a perfectly even torque of the crankshaft.In the V-type cylinder arrangement, often adopted in the larger diesel engines, setting the cylinders alternately at an angle right or left the centre-line, in a ―V‖ formation, makes possible a reduction in total length as compared with an engine that has all the cylinders in line.柴油機(jī)在四個(gè)沖程中，只有一個(gè)沖程即第二個(gè)沖程產(chǎn)生功率，這就是為什么柴油機(jī)需要有若干個(gè)氣缸，其數(shù)目從用于小功率調(diào)車(chē)機(jī)車(chē)的4缸，到用于大功率干線機(jī)車(chē)的16缸或16缸以上。各個(gè)氣缸的曲柄互相排列成一定的角度，把柴油機(jī)工作周期劃分為相應(yīng)數(shù)目的相等部分，這樣就保證了曲軸的扭矩十分均勻。較大功率的柴油機(jī)的氣缸往往按V型排列，氣缸在中線的左側(cè)或右側(cè)，以一定角度交錯(cuò)安排，氣缸以V型排列的柴油機(jī)比全部氣缸單列的柴油機(jī)更能縮短其總長(zhǎng)度。

There is also the two-stroke engine, in which the cycle of operation is completed in a single return stroke of the piston.Near the end of the combustion stroke the 45 piston uncovers an exhaust port, which allows the spent gases to escape, and a further piston movement uncovers the inlet port, through which a charge of air under pressure enters the cylinder behind the piston.As soon as the piston has passed the two ports on return stroke compression begins, and the oil is injected just before the piston reaches the top of the stroke.The power of a two-stroke engine does not go up in proportion to the fact that combustion takes place on every return stroke of the piston, instead of on every alternate return stroke, because the two stroke engine is less efficient than the four-stroke.也有兩沖程的柴油發(fā)動(dòng)機(jī)，它的工作循環(huán)僅由活塞用一個(gè)來(lái)回的行程就完成了。當(dāng)接近燃燒沖程的末端時(shí)，活塞打開(kāi)一個(gè)排氣孔，讓已用過(guò)的廢氣排出去，活塞再進(jìn)一步運(yùn)動(dòng)，打開(kāi)進(jìn)氣孔，空氣通過(guò)進(jìn)氣孔隨著活塞在壓力下進(jìn)入氣缸。一旦活塞在回程中通過(guò)了這兩個(gè)氣孔，就開(kāi)始?jí)嚎s空氣，剛好在活塞到達(dá)上止點(diǎn)之前，噴射燃油。兩沖程發(fā)動(dòng)機(jī)的活塞每次回程都產(chǎn)生燃燒，不像四沖程活塞每隔一次回程才產(chǎn)生燃燒，但其功率并不是按比例增大，因?yàn)閮蓻_程發(fā)動(dòng)機(jī)的效率比四沖程的效率要低。

Of the complicated equipment of a diesel engine, the most important constituent-in effect, the nerve centre is the fuel injection pump.It is driven off the main crankshaft by a series of cams on an independent shaft, and each cam actuates the plunger of one of the cylinders.This plunger traps a small quantity of fuel oil, and delivers it as fine spray into the cylinders above the piston, after which a spring restores the plunger to its out-of-action position.The amount of fuel delivered per stroke can be varied, with a proportionate variation in the power developed by the engine.In a two-stroke engine the camshaft is rotated at the same speed as the main crankshaft, and in a four-stroke engine at half the speed.Another camshaft works the valves which open and close the cylinder ports at precisely the right moments.Correct timing is of the utmost importance, and also extreme accuracy, down to a twenty-thousandth part of an inch, in the grinding of certain parts of the fuel injection pump and the valves.在柴油機(jī)的復(fù)雜設(shè)備中，實(shí)際上最重要的組成部分的核心部分是噴油泵。它是由主軸通過(guò)獨(dú)立軸上的一系列凸輪驅(qū)動(dòng)的，每個(gè)凸輪推動(dòng)一個(gè)氣缸噴油泵的柱

塞，該柱塞封住少量的燃油，并以細(xì)霧狀射入氣缸活塞上方，然后噴油泵的彈簧使柱塞回到“停止”位臵。每個(gè)沖程噴射燃油的數(shù)量可以變化，這就使發(fā)動(dòng)機(jī)產(chǎn)生的功率發(fā)生相應(yīng)的變化。兩沖程發(fā)動(dòng)機(jī)的凸輪軸旋轉(zhuǎn)速度與主軸旋轉(zhuǎn)速度相同，而四沖程發(fā)動(dòng)機(jī)則為主軸轉(zhuǎn)速的一半。另外有一根凸輪軸控制氣閥，它準(zhǔn)確、及時(shí)地打開(kāi)與關(guān)閉氣缸的進(jìn)氣氣孔。校正定時(shí)的工作是極其重要的，而準(zhǔn)確的精密度也是極其重要的，對(duì)噴油泵與氣閥某些部件的研磨精密度可達(dá)到兩萬(wàn)分之一英寸。

The cylinders of a diesel engine would become dangerously overheated if effective measures were not taken to cool them.Each cylinder therefore is encased in a water jacket, which forms part of a circuit through which water is pumped continuously, and cooled by means of air drawn in from the outside atmosphere by large rotary fans, worked off the main crankshaft, or, in the larger diesel-electric locomotives, by auxiliary motors.The fans are often fitted with movable shutters to their air intakes, which open and close automatically, under the control of thermostats, to keep the cylinder temperatures as even as possible, admitting more air when the engine is working hard, and less when it is idling.A second cooling circuit is needed for the lubricating oil, of which a considerable amount is used, and a third, in the case of a diesel-electric locomotive, as with a straight electric locomotive, to prevent overheating in the generators and traction motors.如果不采取有效的冷卻措施，柴油機(jī)的氣缸變得過(guò)熱就會(huì)產(chǎn)生危險(xiǎn)。因此每個(gè)氣缸都圍著一個(gè)水套，水套形成循環(huán)水路的一部分，由水泵驅(qū)使水在回路中不斷地流動(dòng)，并由大型旋轉(zhuǎn)風(fēng)扇從外部鼓入空氣使水冷卻。大型旋轉(zhuǎn)風(fēng)扇是由主軸帶動(dòng)的，而在大型電力傳動(dòng)內(nèi)燃機(jī)車(chē)上則由輔助電動(dòng)機(jī)來(lái)帶動(dòng)。在風(fēng)扇的空氣入口處，通常裝有帶活動(dòng)葉片的百葉窗，葉片受恒溫器控制能自動(dòng)地開(kāi)閉，以保持氣缸溫度盡可能穩(wěn)定。當(dāng)發(fā)動(dòng)機(jī)加大負(fù)荷工作時(shí)，進(jìn)來(lái)的空氣就多些，而在發(fā)動(dòng)機(jī)空轉(zhuǎn)時(shí)，進(jìn)來(lái)的空氣就少些。由于使用大量的潤(rùn)滑油，需要有第二條冷卻回路。而電力傳動(dòng)內(nèi)燃機(jī)車(chē)，與電力機(jī)車(chē)一樣，需要第三條冷卻回路，以防止發(fā)電機(jī)和牽引電動(dòng)機(jī)過(guò)熱。

Special measures are necessary for starting up a diesel engine, seeing that no combustion of the fuel can take place without initial air compression in the cylinder.47 In the smaller diesels this can be done by hand cranking, or by the use of compressed air, or by a device similar to the self-starter of a motor-car, supplied with current from batteries.In a diesel-electric locomotive, however, the general practice is to use current from the storage batteries to drive the generator as though it were a motor, so completely reversing its function;a few moments usually suffice to work the engine by means of the main crankshaft until combustion begins.After this the engine is idled until the locomotive is required to start.柴油機(jī)起動(dòng)必須有專門(mén)的措施，因?yàn)槿绻麣飧變?nèi)沒(méi)有初始的壓縮空氣，燃油就無(wú)法產(chǎn)生燃燒。小型柴油機(jī)的起動(dòng)可以用手搖曲柄或用壓縮的空氣，或用與汽車(chē)上的自動(dòng)起動(dòng)器等類(lèi)似的裝臵，由蓄電池供電，而電力傳動(dòng)內(nèi)燃機(jī)車(chē)一般習(xí)慣用蓄電池的電流驅(qū)動(dòng)發(fā)電機(jī)，就好像該發(fā)電機(jī)是電動(dòng)機(jī)一樣，把它的功能完全倒轉(zhuǎn)過(guò)來(lái)。依靠主曲軸驅(qū)動(dòng)發(fā)動(dòng)機(jī)使氣缸內(nèi)開(kāi)始燃燒，只需要一會(huì)兒的時(shí)間，在此以后直至機(jī)車(chē)需要起動(dòng)之前，發(fā)動(dòng)機(jī)是在空轉(zhuǎn)。

Transmission of power from the diesel engine to the locomotive axles is a simple matter in the smaller diesels.In low-powered railcars and shunters, up to, say, 250 or 300 h.p., a gearbox similar to that of a road motor-car serves the purpose, with a gear selector, a forward and reverse lever, a clutch and accelerator for control.To enable the drive to be taken up smoothly, some form of fluid coupling is often inserted between the engine and the gearbox.Diesel-mechanical transmissions may include as many as eight speeds, both forward and reverse.在小型內(nèi)燃機(jī)車(chē)內(nèi)，柴油機(jī)把動(dòng)力傳給機(jī)車(chē)動(dòng)軸的傳動(dòng)只是個(gè)簡(jiǎn)單的問(wèn)題。在小功率，譬如在250-300馬力以下的鐵路動(dòng)車(chē)和調(diào)車(chē)機(jī)車(chē)上，可以用一種類(lèi)似汽車(chē)使用的變速箱來(lái)達(dá)到這個(gè)目的，它帶有一個(gè)齒輪選擇器，一個(gè)前進(jìn)與后退的推桿、一個(gè)離合器和一個(gè)控制加速器。有些機(jī)車(chē)常用液力耦合器裝在發(fā)動(dòng)機(jī)與變速箱之間，這樣就能平穩(wěn)地進(jìn)行傳動(dòng)。機(jī)械傳動(dòng)的內(nèi)燃機(jī)車(chē)的調(diào)速可以多達(dá)八級(jí)，既能前進(jìn)也能后退。

There is a limit, however, to the range of power which can be transmitted mechanically, and this was the reason why electricity was chosen, at a relatively early date, as the intermediary between diesel engine and rail in the more powerful diesel locomotives.In a diesel-electric locomotive plant the diesel engine dries an electric

generator, normally mounted on the same bedplate, and it is customary for an auxiliary generator to provide for charging the batteries, lighting and electric control.The d.c.current from the main generator drives the traction motors, mounted on the axles in most modern diesel-electric locomotive, and this part of the equipment is exactly the same as that of the electric locomotives.In a diesel locomotive, while an electric transmission is ideal so far as fineness of control is concerned, it adds greatly to the weight, the cost and the complication of the locomotive as a whole.但是，機(jī)械傳動(dòng)的功率范圍是受到限制的，由于這個(gè)原因，大功率的鐵路內(nèi)燃機(jī)車(chē)在較早的時(shí)候就選擇電力傳動(dòng)，作為柴油機(jī)和軌道之間的中間環(huán)節(jié)。電力驅(qū)動(dòng)內(nèi)燃機(jī)車(chē)上由柴油機(jī)驅(qū)動(dòng)一臺(tái)通常裝在同一底板上的發(fā)電機(jī)。一般還有一臺(tái)輔助發(fā)電機(jī)給蓄電池充電，并提供照明與電力控制用電。大多數(shù)現(xiàn)代的電力傳動(dòng)內(nèi)燃機(jī)車(chē)，用主發(fā)電機(jī)發(fā)出的直流電來(lái)驅(qū)動(dòng)安裝于機(jī)車(chē)軸上的牽引電動(dòng)機(jī)，這部分設(shè)備與電力機(jī)車(chē)的完全相同。盡管內(nèi)燃機(jī)車(chē)的電力傳動(dòng)裝臵就控制的靈敏度而言是完善的，但就整體而言，它大大地增加了機(jī)車(chē)的重量、成本和復(fù)雜性。

In recent years, however, such advances have been made in the design of hydraulic transmissions that they are being used successfully in diesel locomotives of up to 2,000 h.p..The core of a hydraulic transmission is what is known as a ―fluid flywheel‖.This comprises, first, a driving member, which is a circular chamber fitted with vanes somewhat resembling those of a turbine, and filled with lubricating oil;and, second, the driven member, similarly provided with vanes and driving the output shaft.可是近幾年來(lái)，液力傳動(dòng)裝臵的設(shè)計(jì)制造亦有很大的進(jìn)展，現(xiàn)在正成功地應(yīng)用在功率高達(dá)2000馬力的內(nèi)燃機(jī)車(chē)上。液力傳動(dòng)裝臵的核心通常稱為“液力飛輪”，它首先包括主動(dòng)輪，這是一個(gè)圓形殼體，裝有葉片，有點(diǎn)像渦輪的葉片，并充滿潤(rùn)滑油；其次是從動(dòng)輪，它同樣裝有葉片，并驅(qū)動(dòng)輸出軸。

Rotation of the vanes of the driving member causes the oil to exert centrifugal pressure against those of the driven member, which rotate at increasing speed until the two, in effect, are locked as one, although the speed of the latter, because of friction, is always very slightly less than that of the former.There is no wear and tear in a fluid flywheel comparable to that in a clutch, and the former has the advantage also that if

any seizure should take place, say in the engine, no serious damage is likely to result, because the oil pressure in the chamber would break down.The diesel-hydraulic locomotive in future is likely to prove a serious rival to the diesel-electric, and hydraulic transmissions also are being used increasingly in diesel railcar power plants.主動(dòng)輪的葉片旋轉(zhuǎn)使油產(chǎn)生離心力，沖擊從動(dòng)輪的葉片，使從動(dòng)輪的葉片旋轉(zhuǎn)速度不斷增加，直到最終咬合成一個(gè)整體，但由于摩擦的關(guān)系，后者的速度總是比前者稍微低一些。一個(gè)液力飛輪裝臵與一個(gè)離合器比較起來(lái)，簡(jiǎn)直可以說(shuō)沒(méi)有磨損；同時(shí)它還有下述優(yōu)點(diǎn)：即如果在傳動(dòng)中卡住，由于在殼體內(nèi)油的壓力會(huì)衰減下來(lái)，柴油機(jī)也不致受到很大的損害。將來(lái)液力傳動(dòng)內(nèi)燃機(jī)車(chē)很可能成為電力傳動(dòng)內(nèi)燃機(jī)車(chē)的重要競(jìng)爭(zhēng)對(duì)手，液力傳動(dòng)裝臵將越來(lái)越廣泛地應(yīng)用在鐵路內(nèi)燃動(dòng)車(chē)的動(dòng)力裝臵中。

Words and Expressions diesel engine：柴油機(jī)；lb.(pound)：磅；sq.in.(square inch)：平方英寸；Fahr.(Fahrenheit)：華氏溫標(biāo)；supercharge：增壓；scavenge：掃除，清除；main line unit：干線機(jī)車(chē)；shunter：調(diào)車(chē)機(jī)車(chē)；fuel injection pump：噴油泵；plunger：柱塞；grind：研磨；shutter：百葉窗；idle：空轉(zhuǎn)；traction motor：牽引電機(jī)；hand cranking：手搖起動(dòng)；railcar：動(dòng)車(chē)；gear selector：變檔桿；forward and reverse lever：前進(jìn)及倒車(chē)控制桿；gearbox：變速箱；clutch：離合器；hydraulic transmission：液傳動(dòng)；diesel-electric locomotive：電傳動(dòng)內(nèi)燃機(jī)車(chē)；bedplate：底盤(pán)；charging：充電；vane：葉片；power plant：發(fā)動(dòng)機(jī)組；coupled to：聯(lián)結(jié)到。50

第二篇：專業(yè)英語(yǔ)教案

專業(yè)英語(yǔ)教案（其中放假1次，期中習(xí)題課1次）

Unit 1 TECTONICS(4課時(shí))（1：The structure of the earth 2：plate tectonic

3：Earthquakes）

一、Word and phrase core;mantle;crust 地核；地幔；地殼 continental crust

大陸地殼

granite;basalt

花崗巖；玄武巖 sial;sima硅鋁層；硅鎂層

surface waves;body..面波；體波 epicentre;focus

震中；震源

lithosphere

巖石圈 tectonic plate

構(gòu)造板塊 continetal drift

大陸漂移

asthenosphere

軟流層 ocean ridge 洋脊 ocean trench 海溝

subduction 俯沖作用

volcanism

火山作用

fold mountain

褶皺山脈

fold;fault

褶皺；斷層 sedimentary rocks 沉積巖

vent

火山口

lava

熔巖 volcanic cones 火山錐

parasitic cone

寄生火山錐

plug

巖頸

volcanic ash

火山灰

二、重點(diǎn)內(nèi)容

1..Within the crust, intricate patterns are created when rocks are redistributed and deposited in layers through the geologic processes of eruption and intrusion of lava, erosion, and consolidation of rock particles, and solidification and recrystallization of porous rock.2.The lithosphere is a relatively inflexible and buoyant layer.It is the layer which floats on the material underneath and as it moves carries the continents that produce continental drift.3.There are three types of plate boundaries:

Divergent(diverge, divergence)boundaries--where new crust is generated as the plates pull away from each other.Convergent(converge, convergent)boundaries--where crust is destroyed as one plate dives under another.Transform boundaries--where crust is neither produced nor destroyed as the plates slide horizontally past each other.4.Earthquakes occur when normal movement of the crust are concentrated into a single shock of a series of sudden shocks.三、詞匯解釋 ocean ridges continental rift rift valley convergent trench arc and back-arc-basin system transcurrent fault abyssal intrusion fold mountains sendimentary rock Unit 2 WEATHERING（4課時(shí)）

(1：Weathering 2：Controls on weathering)

一、Word and phrase mechanical weathering

機(jī)械風(fēng)化 chemical weathering

化學(xué)風(fēng)化 freeze-thaw

凍融

pressure release

卸荷釋重 limestone

石灰?guī)r

hydrolysis

水解作用 quartz

石英

hydration 水合作用 oxidation 氧化作用 alluvium

沖擊層 gravel

砂礫

denudation

剝蝕作用 precipitation

降水 climatic zone

氣候帶 mid-latitude

中緯度

semi-arid

半干旱

tropical wet-dry

熱帶干濕季氣候 watershed

分水嶺 drainage basin

流域

regolith

風(fēng)化層

二、重點(diǎn)

1.The disintegration(breaking into parts)of rock that takes place at or near the surface of the earth is called weathering.2.PHYSICAL WEATHERING It occurs when a force is applied to rock, causing it to disintegrate into its basic components(what it makes of).temperature changing--it expands and contracts rock particles to breaks rock apart.frost action--it condenses water vapor in cooling air to form water that seeps into cracks in rock.organic(have life)activity--plants or other organisms grow and burrow(go into)into cracks in rock, so the rock crumble over time.3.CHEMICAL WEATHERING The process that breaks down rock through chemical changes.The agents of chemical weathering Water Oxygen Carbon dioxide Living organisms Acid rain 4.WeatheringThe movement of weathered material from the site of weathering.Primary agent is gravity, but gravity acts in concert with running water.5.control on weathering-climate

-precipitation-variations in the depth of wreathing for climatic zones from the pole to the tropocs

-geology(chemical composition;the natural of cements in sedimentary rock;joint and bedding plants)

三、詞語(yǔ)翻譯 weathering crust weathering joint mineral deposit by weathering weathering of rock mass decomposition product decomposition reaction disintegration coefficient To move back and forth alternately.a mineral substance waste substance

A simple substance, mixture mechanical weathering landscape marble landscape ecosystem moisture equivalent

measurement of soil moisture constant.fluctuation of temperature

Unit 3 SLOPES（2課時(shí)）

(1：Slope

2：Slope controls 3：Theories of slope evolution movements)

一、words and phrase soil creep

土壤蠕動(dòng) mass movement

塊體運(yùn)動(dòng) strata

地層

overland runoff

地表徑流 sheet wash

片狀沖刷

pediment

山前侵蝕平原（山足面）rockfall山崩

landslide

滑坡

二、重點(diǎn)內(nèi)容

1.slope(definition)2.factor of controlling slope development-climate-geology-vegetation-soil cover-human activity 3.theories of slope evolution-slope decline:w.m.davies

4：Mass

-slope replacement:waltherpenck

-slope retreat:l.c.king

4.mass movement-small movement(soil creep)-fast movement(avalanches)

三、翻譯句子 Mass movements are part of a continuum of erosional processes between weathering and stream transport.Mass movement causes regolith and rock to move down-slope where sooner or later the loose particles will be picked up by another transporting agent and eventually moved to a site of deposition such as an ocean basin or lake bed.Unit 4 HYDTOLOGY（2課時(shí)）The river basin hydrological cycle 2：Drainage basin hydrology 3：Seasonal variations in river flow: the regime

一、words and phrase interception

截流

evapotranspiration 蒸發(fā)和蒸騰總量 capillary rise

毛管上升 aeration zone

包氣帶

overland flow;interflow;base flow

地表徑流；壤中流；地下徑流 water table

潛水面（水位）

basin length;area 流域長(zhǎng)度;流域面積 tributary 支流； trunk stream 干流

drainage density

河網(wǎng)密度

二、重點(diǎn)內(nèi)容

1.The basin hydrological cycle –input(precipitation)and outputs(evapotranspiration and runoff)-interception by vegetation-soil moisture and infiltration

2.The definition of the drainage basin is the area which drains into a particular river or river system.（precipitation via interception, soil moisture and groundwater storage, evapotranspiration）3.Basin plan

4.Stream ordering

6.Drainage density

三、課后練習(xí)

Main components P

precipitation E

evaporation T

transpiration I

infiltration R

runoff G

ground water flow Ic

interception Unit 5 The long profile and Rivers as sediment systems（2課時(shí)）

一、words and phrase upper;middle;lower reach 上中下游 vertical erosion

下切侵蝕 headward erosion

溯源侵蝕 lateral erosion

側(cè)蝕 pot-hole

壺穴 meander

曲流 ox-bow lake

牛軛湖 delta

三角洲 lake basin

湖盆 levee

天然提

rill and gully erosion 細(xì)溝、沖溝侵蝕 clay;silt;sand;粘土；粉砂；砂

suspended sediment

懸浮沉積物 atmospherical fallout

大氣沉降 laminar flow

層流 turbulent flow

紊流 riffle;pool 淺灘；深槽

channel roughness

河道粗糙度

二、重點(diǎn)內(nèi)容

1.As rivers evolve through time and over distance the stream passes through a series of distinct stages: youth(lakes, waterfalls, and rapids, initial uplift)middle youth(headward erosion, deepening of channel)early maturity(a smoothly profile, floodplain)approaching full maturity(meanders, river in equilibrium)full maturity(broad floodplain and freely menders)

2.critical erosion velocity

3.type of flow-laminar flow and turbulent flow

三、理解下圖內(nèi)容

Cross-sectional shape varies with position in the stream, and discharge.Thedeepest part of channel occurs where the stream velocity is the highest.Both width and depth increase downstream because discharge increases downstream.As discharge increases the cross sectional shape will change, with the stream becoming deeper and wider.Unit 6 Meanders and Deltas and estuaries（2課時(shí)）

sandbar

沙壩 thalweg中泓線 estuary 河口

lagoon

瀉湖 salinity

鹽度 coastline

海岸線 dune

沙丘

suspension;saltation;creep

懸移；躍移；蠕移 dust storm

塵暴 windward;leeward

迎風(fēng)；背風(fēng) prevailing wind

盛行風(fēng) deflation hollow

風(fēng)蝕凹地

二、重點(diǎn)內(nèi)容 1.helicoidal flow

2.the wavelength of meanders is dependent on three majors of factors: channel width, discharge, and the nature of the bed and banks.3.factors of affect the formation of deltas: amount and calibre of load, salinity, gradient of coastline , vegetation, low energy river discharge.4.three forms of deltas: arcuate, cuspate, bird’s foot.5.estuaries occur where a coastal area has recently subsided or the ocean level has risen, causing the lower part of the river to be drowned.三、理解下列句子

TerracesGlaciers erode in several ways.:Abrasion and plucking.sediment transportation Glacial Deposition 4.Landforms produced by mountain: Cirques, Glacial Valleys, Arêtes, Horns.三、理解下列圖片內(nèi)容。

第三篇：專業(yè)英語(yǔ)教案

課程名稱：計(jì)算機(jī)專業(yè)英語(yǔ) 授課教師：常文慧 教學(xué)課時(shí)：2學(xué)時(shí)

授課班級(jí)：計(jì)科1101-1105班

授課內(nèi)容：Basic Computer Hardware Components

一、教學(xué)要求

1、掌握計(jì)算機(jī)內(nèi)部、外部常用部件名稱

2、熟悉輸入設(shè)備（input devices）、輸出設(shè)備(output devices)的組成

3、了解計(jì)算機(jī)英語(yǔ)詞匯的簡(jiǎn)稱

4、在對(duì)教材全文的翻譯過(guò)程中掌握專業(yè)文獻(xiàn)的寫(xiě)作技巧

二、教學(xué)目的專業(yè)英語(yǔ)是計(jì)算機(jī)科學(xué)與技術(shù)專業(yè)的一門(mén)必修課，通過(guò)讓學(xué)生閱讀、討論計(jì) 算機(jī)科學(xué)與技術(shù)等專業(yè)有關(guān)的英語(yǔ)詞匯和文章翻譯，培養(yǎng)學(xué)生的閱讀、翻譯及寫(xiě)作專業(yè)文獻(xiàn)的能力，擴(kuò)大學(xué)生的專業(yè)知識(shí)面和提高外語(yǔ)能力。

三、教學(xué)方法

以文字教材為基礎(chǔ)，以精讀和泛讀相結(jié)合強(qiáng)化教學(xué)的重、難點(diǎn)內(nèi)容，結(jié)合課上與學(xué)生的互動(dòng)，以學(xué)生為主體進(jìn)行本門(mén)課的學(xué)習(xí)。

四、教學(xué)內(nèi)容

1、課堂提問(wèn)

（5 minutes）提問(wèn)問(wèn)題“What are the main parts of the computer?”。

通過(guò)此問(wèn)題讓學(xué)生說(shuō)出知道的計(jì)算機(jī)英語(yǔ)詞匯或命令，引導(dǎo)學(xué)生進(jìn)入課文“Basic Computer Hardware Components”，在學(xué)習(xí)英語(yǔ)的同時(shí)給學(xué)生插入熟悉的計(jì)算機(jī)知識(shí)，提高學(xué)生學(xué)習(xí)的興趣。

2、詞匯講解

（25 minutes）

復(fù)習(xí)熟悉的詞匯同時(shí)帶領(lǐng)學(xué)生學(xué)習(xí)陌生單詞，同時(shí)針對(duì)重點(diǎn)和難點(diǎn)讀單詞難，記不住，采用第一次給學(xué)生寫(xiě)出音標(biāo)，領(lǐng)著讀的手段，同時(shí)向?qū)W生介紹單詞快速記憶方法。

重點(diǎn)詞匯：type

v.打字

n.類(lèi)型

bonkers

adj.瘋狂的identify

vt.識(shí)別，鑒別

accessory

n.附件 adj.附屬的

delicate

adj.精巧的，精密的 exotic

adj.外來(lái)的transfer

n.&vt.轉(zhuǎn)寫(xiě)，轉(zhuǎn)移，傳遞

operation n.運(yùn)行，實(shí)施 重點(diǎn)短語(yǔ):

Build into 使??成為組成部分

show up 露出，露面

Find out

找出，發(fā)現(xiàn)，認(rèn)識(shí)到

come up with 提出，拿出

Refer to 提到，談到，打聽(tīng)

floppy disk 軟盤(pán)

Home computer 家用計(jì)算機(jī)

away from 遠(yuǎn)離 簡(jiǎn)寫(xiě)詞匯

CPU(Central Processing Unit)中央處理器

CD(Compact Disc)光盤(pán) 在詞匯及短語(yǔ)的講解中，需結(jié)合例句對(duì)重點(diǎn)詞匯進(jìn)行講解。

The keyboard is the part with the letters and numbers, where you put your hands and type.鍵盤(pán)是印有字母和數(shù)字的部件，你可以把手指放在這些字母和數(shù)字上來(lái)輸入它們。

The keyboard may be attached to or built into one of the computer.鍵盤(pán)可能會(huì)連接或內(nèi)置于計(jì)算機(jī)上。

Calling the mouse an accessory is just one of those gooly things technical people do, and it’s best not to disturb their delicate sensibilities.將鼠標(biāo)叫做附件是技術(shù)人員做的傻事，最好不要碰觸他們敏感的神經(jīng)。

3、文章翻譯講解

（50分鐘）在此環(huán)節(jié)，主要以學(xué)生為主體，采用以下教學(xué)手段。

（1）由于在“Basic Computer Hardware Computer”中，共涉及到了七個(gè)大的段落，分別為計(jì)算機(jī)的不同組成部分，主要分為“Keyboard”“,Monitor”，“Computer or CPU Box”，“Mouse”，“External Drives”，“External Modem”及“Printer”幾個(gè)部分，故可針對(duì)每個(gè)部分的內(nèi)容找出一名學(xué)生進(jìn)行閱讀，針對(duì)不正確的發(fā)音進(jìn)行糾正。

（2）對(duì)每個(gè)段落中涉及到的重點(diǎn)及難點(diǎn)詞匯進(jìn)行講解說(shuō)明，通過(guò)舉例使學(xué)生加深對(duì)重難點(diǎn)詞匯的理解，包括“cellular phone”，“be attached to”，“part”，“know about”，“human being”，“be supposed to”，“take up”，“depend on”，“persist in”等重點(diǎn)詞匯，通過(guò)對(duì)單詞短語(yǔ)的意思進(jìn)行解釋為進(jìn)一步的文獻(xiàn)翻譯奠定基礎(chǔ)。（3）對(duì)七個(gè)不同的段落分別請(qǐng)七個(gè)學(xué)生進(jìn)行翻譯，并針對(duì)翻譯中出現(xiàn)的具體問(wèn)題進(jìn)行糾正講解，在講解翻譯的過(guò)程中穿插專業(yè)文獻(xiàn)翻譯及寫(xiě)作的注意事項(xiàng)，為學(xué)生在將來(lái)專業(yè)文獻(xiàn)的閱讀及寫(xiě)作奠定基礎(chǔ)。

4、課堂小結(jié)

（10分鐘）（1）帶領(lǐng)學(xué)生一起對(duì)本節(jié)課講解的重點(diǎn)詞匯進(jìn)行總結(jié)，同時(shí)對(duì)學(xué)生在翻譯中出錯(cuò)的段落進(jìn)行重復(fù)強(qiáng)調(diào)。

（2）請(qǐng)兩個(gè)學(xué)生分別用兩分鐘時(shí)間結(jié)合新學(xué)的詞匯對(duì)本次課的內(nèi)容進(jìn)行說(shuō)明，重點(diǎn)說(shuō)明計(jì)算機(jī)內(nèi)部、外部的常用部件及課程中涉及到的專業(yè)文獻(xiàn)翻譯、寫(xiě)作的注意事項(xiàng)。

5、課后作業(yè) 課后題：1,2

五、課程難點(diǎn)

計(jì)算機(jī)科學(xué)與技術(shù)專業(yè)詞匯及外圍設(shè)備相關(guān)術(shù)語(yǔ) 計(jì)算機(jī)各外圍設(shè)備的作用

六、教學(xué)方式和手段

強(qiáng)調(diào)口語(yǔ)的教學(xué)，通過(guò)分組討論激發(fā)學(xué)生對(duì)專業(yè)英語(yǔ)學(xué)習(xí)的積極性 結(jié)合多媒體動(dòng)畫(huà)、錄像、課件及板書(shū)進(jìn)行講解 通過(guò)課堂提問(wèn)強(qiáng)調(diào)學(xué)生的課堂參與性

七、參考文獻(xiàn)

1、張強(qiáng)華，司愛(ài)俠.計(jì)算機(jī)專業(yè)英語(yǔ).北京:機(jī)械工業(yè)出版社,2007.2、朱龍.計(jì)算機(jī)專業(yè)英語(yǔ).北京:人民郵電出版社,2012.3、任偉.計(jì)算機(jī)專業(yè)英語(yǔ).北京:清華大學(xué)出版社,2011

4、[英]霍恩比著,王玉章等譯.牛津高階英漢雙解詞典.牛津大學(xué)出版社,2009.5、周生炳.計(jì)算機(jī)英語(yǔ)教程.北京:清華大學(xué)出版社,2005.課程名稱：計(jì)算機(jī)專業(yè)英語(yǔ) 授課教師：常文慧 教學(xué)課時(shí)：2學(xué)時(shí)

授課班級(jí)：計(jì)科1101-1105班

授課內(nèi)容：Word:Working With Text and Style

一、教學(xué)要求

1、掌握word的文本使用與樣式設(shè)置

2、熟悉文本及樣式操作的相關(guān)專業(yè)詞匯及短語(yǔ)

3、通過(guò)對(duì)全文的翻譯理解掌握專業(yè)文獻(xiàn)的寫(xiě)作格式

4、掌握專業(yè)文獻(xiàn)的寫(xiě)作技巧

二、教學(xué)目的本次課主要通過(guò)對(duì)word中文本與樣式設(shè)置的講解，使學(xué)生在技術(shù)上熟悉具體軟件操作的同時(shí)，對(duì)涉及到的專業(yè)詞匯進(jìn)行了深入掌握，通過(guò)對(duì)文章的閱讀翻譯，掌握專業(yè)文檔的寫(xiě)作技巧，提高學(xué)生翻譯及寫(xiě)作專業(yè)文獻(xiàn)的能力。

三、教學(xué)方法

通過(guò)對(duì)實(shí)際軟件的操作結(jié)合本文進(jìn)行講解，由于學(xué)生對(duì)word的操作相對(duì)較為熟練，因此以此為教學(xué)方法能夠激發(fā)學(xué)生學(xué)習(xí)的積極性，同時(shí)通過(guò)與與學(xué)生的互動(dòng)，在活躍的課堂氣氛下進(jìn)行本門(mén)課的學(xué)習(xí)。

四、教學(xué)內(nèi)容

1、知識(shí)回顧

（5 minutes）

對(duì)在“Basic Computer Hardware Components”學(xué)習(xí)中涉及到得重點(diǎn)詞匯及翻譯難點(diǎn)進(jìn)行復(fù)習(xí)，從而能夠?qū)W(xué)生的課下學(xué)習(xí)情況進(jìn)行掌握。

2、課堂提問(wèn)

（5 minutes）提問(wèn)問(wèn)題“How to set the text and style with word?”。

通過(guò)此問(wèn)題讓學(xué)生說(shuō)出知道的word操作方法，引導(dǎo)學(xué)生進(jìn)入課文“Word：Working With Text and Style”，在學(xué)習(xí)英語(yǔ)的同時(shí)給學(xué)生插入熟悉的word操作知識(shí)，并通過(guò)與學(xué)生的互動(dòng)來(lái)提高學(xué)生學(xué)習(xí)的興趣。

3、詞匯講解

（25 minutes）在此環(huán)節(jié)，同樣根據(jù)“溫故而知新”的原則，復(fù)習(xí)熟悉詞匯的同時(shí)帶領(lǐng)學(xué)生學(xué)習(xí)陌生單詞，同時(shí)針對(duì)重點(diǎn)和難點(diǎn)讀單詞，采用第一次給學(xué)生寫(xiě)出音標(biāo)，領(lǐng)著讀的手段。

重點(diǎn)詞匯：

shortcut

n.捷徑

arrow

n.箭頭記號(hào)，箭 keystroke n.鍵擊，按鍵

attribute

n.屬性，品質(zhì)，特征

deselect

n.取消選定

demonstrate v.示范，展示，演示

stationary adj.固定的，不動(dòng)的remain

vi.保持，保留 重點(diǎn)短語(yǔ): Hold down

保持按下，持續(xù)按住

drag and drop 拖拽 Drop-down menu 下拉菜單

format painter 格式刷 Dialog box 對(duì)話框

paragraph symbol 段落符 在詞匯及短語(yǔ)的講解中，需結(jié)合例句對(duì)重點(diǎn)詞匯進(jìn)行講解。

I couldn't let the team take that shortcut.我不能允許我們的團(tuán)隊(duì)走此捷徑 Neither attribute seems particularly beneficial for their clients.這兩種特征似乎 都不是特別有利于他們的客戶。

Experimental psychologists use such exercises to demonstrate cognitive illusions.實(shí)驗(yàn)心理學(xué)家利用這種練習(xí)來(lái)證明認(rèn)知錯(cuò)覺(jué)。

it.你可以在煙火迸發(fā)的地點(diǎn)上面或者附近找個(gè)固定的物體對(duì)焦。Unemployment will remain structurally high.失業(yè)率仍然保持結(jié)構(gòu)性高位。

4、文章翻譯講解

（50分鐘）為了鍛煉學(xué)生在以后的學(xué)習(xí)及工作中閱讀及書(shū)寫(xiě)專業(yè)文檔的能力，在此環(huán)節(jié)，主要以學(xué)生為主體，教師輔助教學(xué)的方法來(lái)進(jìn)行講授，從而不但調(diào)動(dòng)了學(xué)生的積極性，也增加了課堂的活躍性。

（1）在“Word：Working With Text and Style”全文中，關(guān)于“Working With Text”的描述共有4個(gè)小節(jié)，分別敘述如何進(jìn)行“輸入文本”，“刪除文本”，“選擇文本”及“文本格式設(shè)置”，在關(guān)于“Styles”共涉及到6個(gè)小節(jié)在此段落，故需分別請(qǐng)10位學(xué)生進(jìn)行閱讀，并針對(duì)出現(xiàn)的錯(cuò)誤進(jìn)行糾正。

（2）對(duì)各段落中涉及到的重點(diǎn)及難點(diǎn)進(jìn)行講解說(shuō)明，主要包括“blinking cursor”，“be located”，“highlighted”，“depressed”，“increase indent”，“access”，“be recommended”，“make changes from”等重點(diǎn)詞匯及短語(yǔ)，并在講解的同時(shí)通過(guò)舉例使學(xué)生加深對(duì)重難點(diǎn)詞匯的理解。

（3）分別請(qǐng)10個(gè)同學(xué)對(duì)不同段落進(jìn)行翻譯，在糾正學(xué)生翻譯問(wèn)題的過(guò)程中利用多媒體結(jié)合word軟件對(duì)相關(guān)術(shù)語(yǔ)、段落的翻譯進(jìn)行講述，同時(shí)針對(duì)在專業(yè)文檔寫(xiě)作過(guò)程中可能出現(xiàn)的問(wèn)題進(jìn)行說(shuō)明，以避免學(xué)生在后續(xù)專業(yè)文檔的翻譯寫(xiě)作中出現(xiàn)錯(cuò)誤。

5、課堂小結(jié)

（10分鐘）（1）通過(guò)利用多媒體演示word軟件，采用邊操作邊對(duì)本次課相關(guān)術(shù)語(yǔ)進(jìn)行復(fù)習(xí)的手段，帶領(lǐng)學(xué)生對(duì)本次課的主要內(nèi)容進(jìn)行回憶。

（2）請(qǐng)學(xué)生到講臺(tái)，對(duì)其他學(xué)生進(jìn)行word軟件的演示，并配合英語(yǔ)口語(yǔ)的講述，講述完成后，臺(tái)下學(xué)生進(jìn)行評(píng)價(jià)，說(shuō)明存在的問(wèn)題及正確答案。隨后教師針對(duì)存在的問(wèn)題再次進(jìn)行講解。

6、課后作業(yè)

課后題：1,2

五、課程難點(diǎn)

本次課涉及到的專業(yè)名詞較多，在學(xué)生對(duì)文檔的翻譯中，需一邊查看單詞一邊進(jìn)行翻譯，故在此環(huán)節(jié)，需要學(xué)生加強(qiáng)課下對(duì)相關(guān)詞匯的記憶。

六、參考文獻(xiàn)

1、張強(qiáng)華，司愛(ài)俠.計(jì)算機(jī)專業(yè)英語(yǔ).北京:機(jī)械工業(yè)出版社,2007.2、朱龍.計(jì)算機(jī)專業(yè)英語(yǔ).北京:人民郵電出版社,2012.3、任偉.計(jì)算機(jī)專業(yè)英語(yǔ).北京:清華大學(xué)出版社,2011

4、[英]霍恩比著,王玉章等譯.牛津高階英漢雙解詞典.牛津大學(xué)出版社,2009.5、周生炳.計(jì)算機(jī)英語(yǔ)教程.北京:清華大學(xué)出版社,2005.

第四篇：內(nèi)燃機(jī)論文

柴油機(jī)電控燃油噴射系統(tǒng)及排放

韓寧

（大連交通大學(xué) 交通運(yùn)輸工程學(xué)院，遼寧 大連116028）

摘要：柴油機(jī)是一種熱機(jī)，其熱效率和燃油經(jīng)濟(jì)性很高，因此被廣泛應(yīng)用，尤其是大功率內(nèi)燃機(jī)，被廣泛應(yīng)用于船舶、機(jī)車(chē)和電站等。本論文僅討論大功率柴油機(jī)電控噴射系統(tǒng)和排放過(guò)程。

關(guān)鍵字：柴油機(jī)；噴射系統(tǒng)；排放

Diesel engine electronically controlled fuel injection system and emissions

(Dalian Jiaotong University institute of transportation engineering,Dalian Liaoning 116028）

Abstract: the diesel engine is a heat engine, its thermal efficiency and high fuel economy, so widely used, especially high-power internal combustion engine, is widely used in ships, locomotives and power station, etc.This paper discuss the high-power diesel engine electronic control injection system and only discharge process.Key words: diesel engine;Injection system;emissions

0 引言

通常，人們把燃油噴射系統(tǒng)看作是柴油機(jī)的心臟。事實(shí)上，柴油機(jī)沒(méi)有任何一個(gè)部件比燃油噴射系統(tǒng)更重要;沒(méi)有任何一個(gè)部件對(duì)設(shè)計(jì)和加工的要求超過(guò)燃油噴射系統(tǒng)。燃油噴射系統(tǒng)的功能是在精準(zhǔn)的時(shí)刻為柴油機(jī)提供精確定量的燃油。燃油必須以足夠高的壓力通過(guò)適當(dāng)?shù)膰娪推鲊娚洌詫?shí)現(xiàn)在燃燒室內(nèi)的最佳霧化狀態(tài)，并且在有限的時(shí)間內(nèi)與足夠的空氣混合，以實(shí)現(xiàn)充分燃燒，從而使發(fā)動(dòng)機(jī)以盡可能少的燃油消耗和最低的排放發(fā)出預(yù)期的功率在未來(lái)幾年中，柴油機(jī)的發(fā)展趨勢(shì)主要有：更加追求提高燃油經(jīng)濟(jì)性和降低排放，在不斷強(qiáng)化柴油機(jī)的同時(shí)追求高可靠性，越來(lái)越多地應(yīng)用電子控制技術(shù)，在更廣泛的領(lǐng)域特別是汽車(chē)行業(yè)使用柴油機(jī)等等。為了實(shí)現(xiàn)這些目標(biāo)，目前柴油機(jī)已應(yīng)用和將要應(yīng)用的先進(jìn)技術(shù)主要有高壓噴射和電控噴射技術(shù)是目前國(guó)外降低柴油機(jī)排放的重要措施之一，高壓噴射和電控噴射技術(shù)的有效采用，可使燃油充分霧化，各缸的燃油和空氣混合達(dá)到最佳，從而降低排放，提高整機(jī)性能。電控燃油噴射系統(tǒng)的構(gòu)成

電噴柴油噴射系統(tǒng)由燃油噴射系統(tǒng)、控制計(jì)算機(jī)（ECU）和傳感器三部分組成。ECU根據(jù)由轉(zhuǎn)速、節(jié)氣門(mén)踏板位置、進(jìn)氣溫度、進(jìn)氣壓力、燃油溫度、冷卻水溫度等傳感器采到的發(fā)動(dòng)機(jī)運(yùn)行狀態(tài)，用設(shè)定的控制邏輯進(jìn)行計(jì)算，根據(jù)計(jì)算結(jié)果控制噴油系統(tǒng)執(zhí)行電磁閥的動(dòng)作，實(shí)現(xiàn)對(duì)燃油噴射量、噴射時(shí)刻和噴射壓力的動(dòng)態(tài)調(diào)節(jié)。由于燃油的噴射量、噴射時(shí)刻和噴射壓力在柴油機(jī)整個(gè)轉(zhuǎn)速和負(fù)荷范圍都可以通過(guò)標(biāo)定實(shí)驗(yàn)最優(yōu)化，因此電噴柴油機(jī)可以實(shí)現(xiàn)在滿足嚴(yán)格的排放標(biāo)準(zhǔn)條件下的最佳燃油經(jīng)濟(jì)性。電控燃油噴射系統(tǒng)介紹

2.1.電控直列式噴油泵

電控直列式噴油泵是在直列泵基礎(chǔ)上發(fā)展起來(lái)的，是一種由機(jī)械噴油泵到電控噴油泵之間過(guò)渡的非主流產(chǎn)品。它具有與噴油和定時(shí)控制功能或只具備噴油量調(diào)控功能，有些控制系統(tǒng)還具有噴油壓力和噴油速率等控制功能。因?yàn)樗荒軡M足歐Ⅲ排放而且結(jié)構(gòu)復(fù)雜、造價(jià)高，目前國(guó)外工業(yè)國(guó)家已停止生產(chǎn)。2.2電控分配泵

柴油機(jī)電控分配泵采用高速電磁閥控制噴油量及噴油定時(shí)，如德國(guó)博世公司的電控VE泵，噴油峰值噴油壓力接近140MPa。電控分配泵也是只能滿足歐Ⅲ排放的過(guò)渡性非主流產(chǎn)品。2.3電控泵噴嘴系統(tǒng)（EUI）

電控泵噴嘴系統(tǒng)是由凸輪驅(qū)動(dòng)的噴油系統(tǒng)，是世界上最早出現(xiàn)的電噴產(chǎn)品。目前生產(chǎn)電控泵噴嘴系統(tǒng)的有德國(guó)博世（Bosch）公司、美國(guó)卡特彼勒（Caterpillar）公司、美國(guó)德?tīng)柛＃―elphi）公司和美國(guó)康明斯（Cummins）公司。電控泵噴嘴系統(tǒng)北美重型車(chē)用柴油機(jī)中占有統(tǒng)治地位。電控泵噴嘴系統(tǒng)具有以下特點(diǎn)：(1)噴射壓力在所有噴油系統(tǒng)中最高，最高噴射壓力220MPa。(2)結(jié)構(gòu)筒單，可靠性/耐久性最好，幾乎沒(méi)有高壓接頭。

(3)噴油器成本一般，但由于采用頂置凸輪軸和重負(fù)荷傳動(dòng)齒輪系，發(fā)動(dòng)機(jī)成本較高。

(4)噴射壓力隨發(fā)動(dòng)機(jī)轉(zhuǎn)速負(fù)荷變化，不能動(dòng)態(tài)控制。

(5)噴射規(guī)律，后三角型，與發(fā)動(dòng)機(jī)燃燒系統(tǒng)配合較好，有利于降低NOX。(6)噴射規(guī)律可以通過(guò)凸輪型面的設(shè)計(jì)加以調(diào)整。

(7)噴油器體積較大，氣缸頭設(shè)計(jì)中需要與氣道，氣閥及水腔設(shè)計(jì)綜合考慮。(8)噴油時(shí)刻被凸輪型面限制，預(yù)噴能力有限，不能后噴。2.4電控單體泵系統(tǒng)（EUP）

電控單體泵系統(tǒng)主要由單體泵、油管和噴油器組成。電控單體泵是由電控泵噴嘴技術(shù)發(fā)展而來(lái)的。電控單體泵系統(tǒng)在歐洲中型/重型車(chē)用柴油機(jī)中占有統(tǒng)治地位。主要生產(chǎn)廠家是德國(guó)博世公司，在歐美車(chē)用柴油機(jī)市場(chǎng)占據(jù)100%的市場(chǎng)。近年來(lái)，德?tīng)柛Ｒ惭兄瞥隽穗娍貑误w泵，但是市場(chǎng)應(yīng)用剛剛起步，其用戶目前僅局限于中國(guó)的玉柴和大柴。電控單體泵系統(tǒng)具有以下特點(diǎn)：(1)噴射壓力較高180MPa。

(2)結(jié)構(gòu)最簡(jiǎn)單，可靠性/耐久性較好，有少量高壓接頭。

(3)噴油系統(tǒng)成本較低（包括單體泵，高壓油管和常規(guī)噴嘴），采用下置凸輪軸，對(duì)齒輪傳動(dòng)系要求低于EUI，發(fā)動(dòng)機(jī)總成本最低。(4)噴射壓力隨發(fā)動(dòng)機(jī)轉(zhuǎn)速負(fù)荷變化，不能動(dòng)態(tài)控制。(5)噴射規(guī)律，后三角型，與發(fā)動(dòng)機(jī)燃燒系統(tǒng)配合較好。(6)由于高壓油管的存在，凸輪型面對(duì)噴射規(guī)律的影響較弱。(7)噴油時(shí)刻被凸輪型面限制，預(yù)噴能力更加有限，不能后噴。2.5液壓電控泵噴嘴系統(tǒng)（HEUI）

液壓電控泵噴嘴系統(tǒng)將電控和液壓技術(shù)相結(jié)合主要由美國(guó)卡特彼勒（Caterpillar）公司生產(chǎn)。HEUI系統(tǒng)按時(shí)間控制噴射過(guò)程，噴射壓力與發(fā)動(dòng)機(jī)轉(zhuǎn)速無(wú)關(guān)，可在寬廣的工況范圍內(nèi)保持所需要的噴油壓力。HEUI系統(tǒng)主要應(yīng)用在北美中型車(chē)用柴油機(jī)中。該系統(tǒng)的工作具有以下特點(diǎn)：(1)噴射壓力較高，180MPa。

(2)理論上在所有發(fā)動(dòng)機(jī)轉(zhuǎn)速及負(fù)荷可隨意調(diào)節(jié)噴射壓力。(3)噴射時(shí)刻靈活。

(4)噴射規(guī)律類(lèi)似高壓共軌，但初始噴射率比高壓共軌略低。(5)多次噴射能力有限，預(yù)噴由硬件設(shè)計(jì)實(shí)現(xiàn)，后噴困難。

(6)噴油器結(jié)構(gòu)較復(fù)雜，液壓油(5～25MPa)及柴油(低壓及高壓)兩套油 路。

(7)氣缸蓋設(shè)計(jì)復(fù)雜，必須保證液壓油及低壓柴油兩套油路的密封。(8)由于采用發(fā)動(dòng)機(jī)潤(rùn)滑油作為液壓油，對(duì)潤(rùn)滑油的要求高于常規(guī)柴 油機(jī)，更換周期也更加嚴(yán)格。(9)發(fā)動(dòng)機(jī)的維護(hù)保養(yǎng)要求較高。

(10)低溫下發(fā)動(dòng)機(jī)潤(rùn)滑油粘度大，造成冷起動(dòng)困難。(11)噴油系統(tǒng)功率消耗較大，機(jī)油壓力靠泄放調(diào)控。我國(guó)機(jī)車(chē)柴油機(jī)采用電控燃油噴射的概況

我國(guó)機(jī)車(chē)柴油機(jī)無(wú)論是戚墅堰機(jī)車(chē)車(chē)輛廠生產(chǎn)的16V280/300(6400公制馬力,4707kW)還是大連機(jī)車(chē)車(chē)輛廠生產(chǎn)的12V280/320(6000公制馬力,4413kW)柴油機(jī),其電子控制燃油噴射系統(tǒng)均成套購(gòu)自Bosch公司。資陽(yáng)內(nèi)燃機(jī)車(chē)廠生產(chǎn)的16V280ZJG(5750公制馬力,4229kW)型柴油機(jī)的電控燃油噴射系統(tǒng)是由Woodward公司提供電噴控制器、功率調(diào)節(jié)器和EDS電噴頭,資陽(yáng)廠生產(chǎn)柱塞泵、噴油器等相關(guān)產(chǎn)品。雖然以上各種機(jī)車(chē)柴油機(jī)在裝用了電控燃油噴射系統(tǒng)后性能和經(jīng)濟(jì)性都有所提高(圖1、2),但也僅僅局限在1~2臺(tái)機(jī)車(chē)柴油機(jī)上實(shí)現(xiàn)。大批量、低價(jià)位、高可靠性的電子噴射技術(shù)產(chǎn)品要組織裝車(chē),尚有待進(jìn)一步的進(jìn)行研制和考核。機(jī)車(chē)柴油機(jī)裝用電控燃油噴射系統(tǒng)的社會(huì)和經(jīng)濟(jì)效益

通過(guò)采用高壓電控燃油噴射系統(tǒng),可以提高機(jī)車(chē)柴油機(jī)的經(jīng)濟(jì)性,尤其是可以降低機(jī)車(chē)柴油機(jī)部分工況下的油耗,降低最低穩(wěn)定空轉(zhuǎn)轉(zhuǎn)速。降低空轉(zhuǎn)轉(zhuǎn)速意味著柴油機(jī)內(nèi)部機(jī)械阻力降低,柴油機(jī)空轉(zhuǎn)油耗降低,同時(shí)也可以使我國(guó)機(jī)車(chē)柴油機(jī)在標(biāo)定工況的燃油消耗率降低到200g/kW·h以下,提高柴油機(jī)的經(jīng)濟(jì)性。柴油機(jī)最低穩(wěn)定空轉(zhuǎn)轉(zhuǎn)速降低10%,空轉(zhuǎn)油耗率可以降低10%,可使我國(guó)鐵路機(jī)車(chē)行業(yè)每年節(jié)約燃料費(fèi)2·5~3億元,同時(shí),機(jī)車(chē)柴油機(jī)的運(yùn)用壽命和可靠性將大大增加。因此,我們要大力發(fā)展高壓電控燃油噴射系統(tǒng)技術(shù)與產(chǎn)品,使機(jī)車(chē)柴油機(jī)技術(shù)攀升一新的高度。如果國(guó)產(chǎn)機(jī)車(chē)柴油機(jī)(240、280系列)采用高壓電控燃油噴射系統(tǒng),以智能化的微電子控制(執(zhí)行)裝置取代目前使用的結(jié)構(gòu)復(fù)雜的機(jī)械結(jié)構(gòu),并設(shè)有機(jī)車(chē)柴油機(jī)狀態(tài)檢測(cè)和故障報(bào)警功能(在線),可以使國(guó)產(chǎn)機(jī)車(chē)柴油機(jī)在性能和可靠性檔次產(chǎn)生一個(gè)質(zhì)的飛躍,跟上世界先進(jìn)水平。同樣,采用高壓電控燃油噴射系統(tǒng),既具有保護(hù)環(huán)境的長(zhǎng)遠(yuǎn)社會(huì)效益,又具有滿足環(huán)保排放法規(guī)、促進(jìn)產(chǎn)品出口的現(xiàn)實(shí)意義。各種類(lèi)型發(fā)動(dòng)機(jī)的CO2排放比較

雖然現(xiàn)有的排放規(guī)定主要是強(qiáng)調(diào)降低NOx和顆粒物質(zhì)(PM)的排放量,但是CO2的排放無(wú)論是從環(huán)保角度,還是從用戶的運(yùn)營(yíng)費(fèi)用方面考慮也是至關(guān)重要的。圖1對(duì)各種內(nèi)燃機(jī)的CO2排放水平進(jìn)行了比較〔1〕。SI(火花點(diǎn)火)汽油發(fā)動(dòng)機(jī)被選作比較的基準(zhǔn),所以它的CO2總排放水平是以100%的參考值給出的。在圖中,CO2的排放被分成兩部分。其中第一部分代表發(fā)動(dòng)機(jī)單獨(dú)運(yùn)轉(zhuǎn)所產(chǎn)生的CO2,該CO2是發(fā)動(dòng)機(jī)效率和燃油化學(xué)成分的函數(shù)。

第二部分是在燃料生產(chǎn)和運(yùn)輸過(guò)程中所排放的所有CO2。圖中右手側(cè)欄中還給出了每種發(fā)動(dòng)機(jī)的最大熱效率以供參考。渦輪增壓、中冷式DI(直噴式)柴油機(jī)具有最低的CO2排放水平。這是由于此種發(fā)動(dòng)機(jī)熱效率好和燃料在生產(chǎn)過(guò)程中生成CO2量少的緣故。因此,在參比的幾種發(fā)動(dòng)機(jī)中,NA(自然吸氣)和T(渦輪增壓、中冷)柴油機(jī)的CO2排放特性最好。廢氣排放法規(guī)的比較

柴油機(jī)可以在滿足所有廢氣排放規(guī)定的同時(shí)保持其明顯的燃油經(jīng)濟(jì)性優(yōu)勢(shì)。在日本、美國(guó)和歐洲,廢氣排放規(guī)定也一年比一年嚴(yán)格。圖2示出了每個(gè)國(guó)家廢氣排放規(guī)定水平的比較。在歐洲,Euro-Ⅱ和Euro-Ⅲ法規(guī)定與美國(guó)1994年和199年的法規(guī)類(lèi)似。然而,日本在1998~1999年對(duì)NOx的規(guī)定卻是最嚴(yán)格的。因此有必要優(yōu)化發(fā)動(dòng)機(jī)以滿足每個(gè)國(guó)家的規(guī)定。在美國(guó),考慮到要在過(guò)渡工況進(jìn)行測(cè)試,從2004年開(kāi)始實(shí)施的排放法規(guī)成為全球最為嚴(yán)格的NOx法規(guī)。從2004年開(kāi)始實(shí)施的顆粒物質(zhì)(PM)排放法規(guī)將與1998年的保持一樣。而且,在歐洲,制定有望在2005年左右開(kāi)始生效的Euro-Ⅳ法規(guī)的基礎(chǔ)工作正在進(jìn)行。在日本,對(duì)1998-1999年以后開(kāi)始實(shí)施的法規(guī)也已開(kāi)始納入計(jì)劃之中并開(kāi)始進(jìn)行調(diào)研。此 外,在歐洲、美國(guó)和日本之間,協(xié)調(diào)全球的廢氣排放規(guī)定的討論和調(diào)研也在進(jìn)行之中。所以,在21世紀(jì),柴油機(jī)廢氣排放法規(guī)將很可能在全球范圍內(nèi)得到統(tǒng)一。參考文獻(xiàn)

[1]、徐家龍等.柴油機(jī)電控噴油技術(shù).內(nèi)燃機(jī)燃油噴射和控制 [2]、《Papers CIMAC DAY 1999 Shanghai》譯者：董金龍 校者:蘇明

[3]、大連內(nèi)燃機(jī)車(chē)研究所.內(nèi)燃機(jī)車(chē)技術(shù)的昨天、今天和明天.中國(guó)鐵道出版社 [4]、董堯清.柴油機(jī)共軌式電控噴射系統(tǒng)的進(jìn)展.國(guó)外內(nèi)燃機(jī) [5]、劉巽俊.內(nèi)燃機(jī)的排放與控制[M].北京:機(jī)械工業(yè)出版社 [6]、陳冠國(guó)機(jī)械設(shè)備維修【M】，機(jī)械工業(yè)出版社 [7]、市場(chǎng)百科，柴油機(jī)發(fā)展[OL]

第五篇：專業(yè)英語(yǔ)教案10酶

Lesson 10 Enzymes酶

Enzymes are gigantic molecules with typical molecular weights ranging from about 6000 to more than 600,000.酶是大分子，大多數(shù)分子量在6000到60萬(wàn)間。Moreover, enzymes are much more complex structurally than the catalysts considered thus far in the section, and their catalytic sites are far more intricate.而且，酶在結(jié)構(gòu)上比這章中迄今所討論的催化劑要復(fù)雜的多，他們的催化位置也十分復(fù)雜。Enzymes have evolved by the life process to be extremely specific catalyst;each enzyme is a catalyst for only one biological reaction or, sometimes, one class of reaction.生命過(guò)程中酶是十分特殊的催化劑，每個(gè)酶是只催化一種（有時(shí)是一類(lèi)）生物反應(yīng)的催化劑。The typical enzyme has a catalytic site that bonds specifically to a single reactant and activates it.典型的具有一個(gè)催化點(diǎn)，只能健合特定的單一反應(yīng)物并激活它。The catalytic site is multifunctional, bonding to the reactant at more than one position, almost to the exclusion of all but closely similar molecules(often products), and these similar molecules are reaction inhibitors.催化位置是多功能的，鍵合到反應(yīng)物上多于一個(gè)位置，除了相似的分子或產(chǎn)品外，幾乎排除所有的位置，這些相似的分子是反應(yīng)阻聚劑。Enzymes catalyze conversion of biological molecules with very high selectivities and at high rates, typically in the range of 10 to l000 molecules/(enzymes).酶以高選擇性高速度催化生物分子的轉(zhuǎn)化，每個(gè)酶催化的典型范圍為10到1000分子

Each enzyme has a unique three-dimensional structure that usually includes a pocket or cleft presenting an array of functional groups positioned to bond to complementary functional groups of the reactant molecule.酶具有獨(dú)一無(wú)二的三維結(jié)構(gòu)，通過(guò)包括缺陷，能夠與反應(yīng)物分子的功能團(tuán)完全結(jié)合。The region of the cleft is a three-dimensional microenvironment, and the bonding of the reactant is comparable to a highly specific chemisorption.缺陷的區(qū)域是三維的微環(huán)境，對(duì)于反應(yīng)物的鍵合具有高化學(xué)選擇性。Nature's process of Darwinian selection has led to the biosynthesis of individual enzyme molecules each of which is in essence a unique multifunctional catalytic site that allows bonding and conversion of a particular reactant or class of reactants.達(dá)爾文的自然進(jìn)化論導(dǎo)致了單個(gè)酶分子的生物合成，允許特定反應(yīng)物的轉(zhuǎn)化。Other chemical properties of enzymes besides those of the catalytic site are important also: the functional groups on the outer surface, for example, determine the enzyme's affinity for particular locations in the biological cell, such as the aqueous environment of the cytoplasm or the hydrophobic environment of a cell wall or other membrane.除了催化位置外，酶的其它化學(xué)性質(zhì)也很重要：外部空間的官能團(tuán)決定了生物細(xì)胞特定位置酶的親和性，如細(xì)胞質(zhì)的水性環(huán)境或細(xì)胞壁或其它膜的疏水性。

Enzymes catalyze biological reactions;and since living organisms usually exist only at relatively mild temperatures, most enzymes function only under these conditions.由于生物體通常存在于相對(duì)溫和的環(huán)境下，酶催化的生物反應(yīng)通常在這樣的條件下進(jìn)行。Enzymes are delicate and do not retain their structures under conditions much outside the range characteristic of living organisms, although they may function in vitro in atypical environments such as nonaqueous solvents.雖然酶的結(jié)構(gòu)在生物體以外的范圍內(nèi)不能保證，但是也可能在體外這種非水性溶劑的環(huán)境中起作用。Some organisms, such as those living in hot springs, have adapted to relatively high temperatures, and they could not exist without enzymes that are stable and active at these temperatures.在溫泉中存在的某些有機(jī)體已經(jīng)適應(yīng)了相對(duì)高的溫度，在這樣的溫度下，如果沒(méi)有酶，有機(jī)體會(huì)變得不穩(wěn)定。

There is a great variety of biological reactions, including, for example,(1)the break down of proteins and sugars occurring in the digestive tracts of animals,(2)the biosynthetic reactions that lead to growth and replacement of living organisms,(3)photosynthesis, and(4)oxidations that proceed by intricate pathways that convert food(e.g., sugars, proteins, etc.)into CO2 water and energy in a biologically useful form.例如，有大量的生物反應(yīng)，（1）動(dòng)物的消化道內(nèi)發(fā)生蛋白質(zhì)和糖的斷裂，（2）生物合成反應(yīng)導(dǎo)致活的有機(jī)體的生長(zhǎng)和取代，（3）光合作用，（4）通過(guò)氧化，以錯(cuò)綜復(fù)雜的方式把食物轉(zhuǎn)化為CO2，水和生物利用形式的能量。

Many enzyme-catalyzed reactions take place in biological cells.許多酶催化反應(yīng)發(fā)生在生物細(xì)胞內(nèi)。

The contents of cells are organized into well-defined domains.細(xì)胞是很好的界定區(qū)域。The cytoplasm is an aqueous biological soup with many molecules, including reactants, products, and enzymes in solution.細(xì)胞質(zhì)是由許多分子的水相細(xì)胞漿，包括反應(yīng)物，產(chǎn)品，酶。The membranes are much more highly structured.膜是高度構(gòu)造的。Enzymes are also present in membranes and in cellular subunits called organelles.酶也包含在膜和細(xì)胞子單元中，稱為細(xì)胞器。These bound enzymes are sometimes present in arrays that can be described as assembly lines.這些酶有機(jī)以序列的形式出現(xiàn)，被描述為裝配線。Evidently, the product of reaction in one enzyme is transported to the next enzyme in line so that a sequence of reactions takes place efficiently.很明顯地，一個(gè)酶反應(yīng)的產(chǎn)品進(jìn)行裝配線的下一個(gè)酶，使反應(yīng)高效的依次發(fā)生。Nature's catalysts function in highly sophisticated reactors.在高度復(fù)雜的反應(yīng)器中發(fā)生自然的催化反應(yīng)。

Enzymes are usually named for the reactions they catalyze.酶通常以其催化的反應(yīng)命名。For example, lysozyme catalyzes reactions that lead to the breakdown by hydrolysis(lysing)of polysaccharides;isomerases catalyze isomerization reactions;dehydrogenases catalyze dehydrogenation reactions;and so forth.例如，溶菌酶催化的反應(yīng)使多糖水解，異構(gòu)酶催化異構(gòu)化反應(yīng)，脫氫酶催化脫氫反應(yīng)，等等。More specifically, alcohol dehydrogenases catalyze alcohol dehydrogenations, and L-lactate dehydrogenase catalyzes the dehydrogenation of L-lactate(to give pyruvate).更特別的是，醇脫氫酶催化醇的脫氫，L－乳酸脫氫酶催化L－乳酸的脫氫（得到丙酮酸鹽）。Because the composition and structure of one kind of enzyme from one plant, animal, or bacterium may be different from those of the same kind of enzyme from another plant, animal, or bacterium, a further specification includes the source, for example, horse liver alcohol dehydrogenase.因?yàn)橹参?、?dòng)物或細(xì)菌中酶的組成和結(jié)構(gòu)不同于其它植物、動(dòng)物或細(xì)菌中相同類(lèi)型的酶，所以需要更進(jìn)一步的分類(lèi)，例如，馬肝醇脫氫酶。