机械专业英语21~24章

1、lesson 21: introduction to automobilen 词汇讲解n 课文分析n 练习答案本课教学目标：1. 理解汽车差速器、燃油喷射器的作用；2. 掌握与汽车相关的专业词汇；3. 熟悉独立主格、伴随壮语等语法现象。section ： words and phases1. 重点专业名词解析2. 词性转换3. 专有名词的通用含义4. now you will have 5 minutes to skim over the new words and phrases, marking the special words you cant understand. 1. 重点专业名

2、词解析n differential n suspension n transmission n driving axle & driving shaft differentialn 汽车发动机的动力经离合器、变速器、传动轴，最后传送到驱动桥再左右分配给半轴驱动车轮，在这条动力传送途径上，驱动桥是最后一个总成，它的主要部件是减速器和差速器。减速器的作用就是减速增矩，这个功能完全靠齿轮与齿轮之间的啮合完成，比较容易理解。而差速器就比较难理解，什么叫差速器，为什么要“差速”？n 汽车差速器是驱动轿的主件。它的作用就是在向两边半轴传递动力的同时，允许两边半轴以不同的转速旋转，满足两边车轮尽可能

3、以纯滚动的形式作不等距行驶，减少轮胎与地面的摩擦。 suspensionn 车身好比是人的上半身,轮胎好比是人的脚,悬挂系统就好比是人的腿。n 汽车悬架包括弹性元件，减振器和传力装置等三部分，这三部分分别起缓冲，减振和力的传递作用。transmissionn 发动机的输出转速非常高，最大功率及最大扭矩在一定的转速区出现。为了发挥发动机的最佳性能，就必须有一套变速装置，来协调发动机的转速和车轮的实际行驶速度。变速器可以在汽车行驶过程中，在发动机和车轮之间产生不同的变速比，通过换挡可以使发动机工作在其最佳的动力性能状态下。变速器的发展趋势是越来越复杂，自动化程度也越来越高，自动变速器将是未来的主流

4、。driving axle & driving shaft n 驱动桥处于动力传动系的末端，其基本功能是增大由传动轴或变速器传来的转矩，并将动力合理的分配给左、右驱动轮，另外还承受作用于路面和车架或车身之间的垂直立、纵向力和横向力。驱动桥一般由主减速器、差速器、车轮传动装置和驱动桥壳等组成。2. 词性转换n ignition n ignite vt 点燃；激起 vi 着火n lubrication n lubricate vt 使润滑 vi 起润滑作用n cylinder n cylindrical adj 圆柱形的n intermittent adj intermission n 间

5、歇，休息时间； intermittence n 断续性，周期性n compensate v compensation n补偿 ，补偿金 ，报酬 q did you get any compensation when you were dismissed from your job?q the job is hard but the compensation is good.3. 专业名词的通用含义n differential n 差别，差速器；adj 差别的n muffler n 消声器，围巾，厚手套n tire n 轮胎；vt 使疲劳；vi 疲劳，厌烦（+of）q she never tir

6、es of talking about her hometown.n transmission n 变速器，传送，传播q the transmission of diseasesn manifold n 多种，管；adj 种种的q manifold dutiesn now please read the new words after me for 2 times.n after that, you will have 10 minutes to remember as many words as you can.section ： textn at first, read the first

7、 paragraph silently in two minutes, please.paragraph :n automobile（fig.6.1） is a self-propelled vehicle used for travel on land. the term is commonly applied to a four-wheeled vehicle designed to carry two to six passengers and a limited amount of cargo, as contrasted with (与.比较) a truck, which is d

8、esigned primarily for the transportation of goods and is constructed with larger and heavier parts, or a bus (or omnibus or coach), which is a large public conveyance designed to carry a large number of passengers and sometimes additionally small amounts of cargo.n 一般来说，汽车是指陆地上行驶的机动式车辆，具有四个轮子，用来搭载两至

9、六名乘客和少量货物。我们可以把它与卡车或公汽对比一下，卡车的零部件更大更重，主要用来运输货物；公共汽车(或公共马车、长途汽车)是一种大型的公共运输工具，用来搭载大量的乘客，有时也附加地运输少量的货物。 oral english practice :n please describe the functions of an automobile, a truck and a bus separately!n read the second paragraph silently in two minutes, please.paragraph :n differential, fuel injec

10、tion, ignition, internal-combustion engine, lubrication, muffler, odometer, shock absorber, speedometer, steering system, suspension, tachometer, tire and transmission are the main operation and technical features of automobiles.n 差速器、燃油喷射器、点火器、内燃机、润滑装置、消声器、里程表、减震器、速度计、驾驶装置、悬挂、转速计、轮胎和变速器反应了小汽车的主要操作特

11、性和技术特性。paragraph :n differential and fuel injection system are introduced in this lesson, with other components presented in the following lessons.n 本课介绍了差速器和燃油喷射系统，其他零部件将在后续几课中介绍。独立主格结构（一）： 独立主格结构的构成： 名词(代词)+现在分词、过去分词；名词(代词)+形容词；名词(代词)+副词；名词(代词)+不定式；名词(代词) +介词短语构成。（二） 独立主格结构的特点：1）独立主格结构的逻辑主语与句子的主语不

12、同，它独立存在。2）名词或代词与后面的分词，形容词，副词，不定 式，介词等是主谓关系。3）独立主格结构一般有逗号与主句分开。n the test finished, we began our holiday.= when the test was finished, we began our holiday.考试结束了，我们开始放假。the president assassinated, the whole country was in deep sorrow.= after the president was assassinated, the whole country was in de

13、ep sorrow.总统被谋杀了，举国上下沉浸在悲哀之中。weather permitting, we are going to visit you tomorrow.如果天气允许，我们明天去看你。this done, we went home.工作完成后，我们才回家。the meeting gone over, everyone tired to go home earlier.会议结束后，每个人都想早点回家。he came into the room, his ears red with cold.他回到了房子里，耳朵冻坏了。he came out of the library, a la

14、rge book under his arm.他夹着本厚书，走出了图书馆。n now well come to paragraph four, the most difficult one in this passage, please read the it silently in 5 minutes,.paragraph :n differential in the automobile is a set of gears used on the driving axle. the two wheels on the driving axle must be interconnected

15、in order to receive their energy from the same source, the driving shaft; at the same time they must be free to revolve at different speeds when necessary (e.g., when rounding a curve, the outer wheel travels farther and thus must revolve faster than the inner wheel in order to prevent skidding).n 汽

16、车差速器由装在驱动桥上的一套的齿轮组成。驱动桥两端的车轮必须互连，以便从同一个动力源即传动轴上获取能量；同时，必要时，两个车轮必须能自由地以不同的速度旋转（例如，拐弯时，外侧的轮子比内侧的行驶的距离更远，为了避免打滑，故其转速应更快）。 n these two requirements are met by the differential gearing. furthermore, through it the rotating motion of the driving shaft is transmitted to the axle and the wheels. the axle is

17、 in two halves; to each half is attached a wheel at one end and, at the inner end, a gear. the end of the driving shaft is also equipped with a gear. by an ingenious arrangement (fig.6.2) of these and other gears, together constituting the differential, a difference in speed of the two wheels is com

18、pensated for without a loss of tractive force. n 使用差动传动装置能同时满足这两个要求。此外,通过差速传动装置可以把传动轴的旋转运动传递给驱动轴和车轮。驱动轴由两个半轴组成；每个半轴外端装了一个车轮，内端装了了一个(半轴)齿轮。传动轴的一端也装了一个齿轮。通过精巧地布置上述和其他的一些齿轮组成差速器，两个车轮的速度差异就能得到补偿，且不损失牵引力。 n 左侧大图表示其基本结构。n 右上图表示2侧半轴同步转动时，行星齿轮不转，而带着两侧半轴同步转动。n 右下图表示当右侧半轴转速超过左侧半轴时，其极端情况是左半轴停止转动时，由于传动轴强迫盆齿以一定的

19、速度继续转动，2个行星齿轮便会产生左右相反的转动，而该转动又会使右侧半轴在原来跟随盆齿转动的基础上又产生一个向前的转动量。这时右半轴的转速来自于两部分原因：第一，盆齿的转动，第二，行星齿轮的转动。因此，行星齿轮组转动的结果相当于把不转动或转动慢的一侧半轴的转速传递给了另一侧半轴。所以，当盆齿转动速度一定的时候，两侧半轴的转速和是一个定值，而差速器的作用就是在这个前提下，使左右半轴的速度可以自由分配。 n 常见的差速器的缺点是：当一个车轮走在干硬的地面上而另一个车轮走在湿滑的地面上时，差速器会导致走在打滑地面上的轮子转速加倍，而使另外一个轮子保持静止。使用防滑差速器则能避免出现这一危险情况，这种

20、分速器在某个车轮开始打滑时只给另一个车轮供给能量，从而保持汽车移动。 oral english practice :n is a differential a part of driving axle? and whats its function?n do driving axle and driving shaft refer to the same thing? if not, whats the difference between them?n now we will come to the last paragraph, read it silently in 5 minutes,

21、 please!paragraph :n fuel injection system in an internal-combustion engine delivers fuel or a fuel-air mixture to the cylinders by means of pressure from a pump. it was originally used in diesel engines because of diesel fuel's greater viscosity and the need to overcome the high pressure of the

22、 compressed air in the cylinders. a diesel fuel injector sprays an intermittent, timed, metered quantity of fuel into a cylinder, distributing the fuel throughout the air within.n 内燃机上的燃油喷射系统通过泵产生的压力来将油或油气混合物传递给汽缸。燃油喷射系统最早用在柴油机上，因为柴油的黏度较大,且需克服汽缸里受压缩空气的高压。柴油喷射器间歇地、定时地将一定量的柴油喷洒到汽缸中，使燃油与空气充分混合。 n fuel

23、injection is also now used in gasoline engines in place of a carburetor. in gasoline engines the fuel usually is injected into the intake manifold and mixed with air, and the resulting mixture is delivered to the cylinder. modern fuel injection systems use computers to regulate the process. fuel inj

24、ection results in more efficient fuel combustion, improving fuel economy and engine performance and reducing polluting exhaust emissions. oral english practice :n fuel injection system can be used both in diesel engine and gasoline engine, however, is there any difference between them?section ： exer

25、cisesn now its time to do the exercises. and please finish them in five minutes.n this is the end for lesson 21.n it will be pretty good if you could review lesson 21 and preview lesson 22 in your spare time.lesson 22 internal combustion enginen 词汇讲解n 课文分析n 练习答案本课教学目标：1. 掌握内燃机的分类方法；2. 掌握与内燃机相关的专业词汇；

26、3. 翻译技巧：信*达*雅section ： words and phasesn see if you can pronounce these words rightly:q exothermic 9eksejw:mik adj. 化发热的q petroleum pi5treuliem n. 石油 q turbocharge t:bejtfb:dv vt. 用涡轮给(发动机)增压 n pay close attention to the words concerning an internal combustion engineq pistonq rotorq connecting rodq

27、cylindern now please remember the new words and phrases as fast as you can. section ： textn at first, read the first paragraph silently in 3 minutes, please.paragraph :n the internal combustion engine is a heat engine in which the burning of a fuel occurs in a confined space called a combustion cham

28、ber. this exothermic reaction of a fuel with an oxidizer creates gases of high temperature and pressure, which are permitted to expand. the defining feature of an internal combustion engine is that useful work is performed by the expanding hot gases acting directly to cause movement, for example by

29、acting on pistons, rotors, or even by pressing on and moving the entire engine itself.n 内燃机是一种热机，燃料在其被称为燃烧室的密封空间内燃烧。燃料和氧化剂间的放热反应产生可膨胀的高温高压气体。内燃机的显著特点是能做有用功，即膨胀的受热气体直接作用在物体上并使其运动，如活塞、转子，乃至整个内燃机本身。oral english practice :n whats an internal combustion engine?n say whats you know about an internal combu

30、stion engine as much as you can.n read the second paragraph silently in two minutes, please.paragraph :n car engines vary in design, but certain elements are common to all engines and are used for engine classification. engines can be classified in several ways such as the number of cylinders, the g

31、eometry of the block, or type of ignition system used. the two major engine types in use are spark ignition (gasoline engine) and compression ignition (diesel engine) which use different types of fuel. the following are ways engines are classified.n 汽车内燃机因设计的不同而不同，但某些元件是所有内燃机所共有的，并用作内燃机的分类依据。内燃机可按气缸

32、的数目、气缸的排列方式和点火系统的类型等方式分类。常用的两大类内燃机是火花点火式（汽油机）和压缩点火式（柴油机）内燃机，他们使用不同种类的燃料。下面是内燃机的分类方法。 oral english practice :n in how many ways can engines be classified? and what are they?n flip through the third paragraph in two minutes, please.paragraph :n fuel burned:n fuel burned provides a broad engine classif

33、ication. two types of fuel are in general use: gasoline and diesel oil. gasoline car engines use spark ignition whereas diesel engines use compression ignition (no spark.) alternate fuels such as liquefied petroleum gas (lp-gas), gasohol (90% gasoline, 10% alcohol), and pure alcohol are used in very

34、 limited situations.n 按所用燃料分类是使用的较为广泛的一种分类方法。汽油和柴油是使用的最为广泛的两种燃料。汽油机采用火花点火而柴油机采用压缩点火（无火花）。诸如石油液化气、酒精-汽油混合燃料（90汽油，10酒精）和纯酒精等代用燃料使用地较少。 oral english practice :n how many kinds of fuel can be in use in internal combustion engines according to paragraph 3? and what are they?n now well come to paragraph f

35、our, please read the it silently in 3 minutes,.paragraph :n block geometry:n there are four types of engine block geometry: v-type, inline, horizontally opposed and slant. each refers to the orientation of the cylinders as viewed from the front or back of the engine. a v-type has two angled rows of

36、cylinders, which form a “v.” an inline engine arranges the cylinders vertically in a row. the horizontally opposed engine has the cylinders horizontal and opposing each other. a slant design is one row of angled cylinders forming a half “v.” a slant block allows the hood line to be lower. n 气缸有四种排列方

37、式：v型、立式、卧式对置和倾斜布置。每一种方式是指气缸从内燃机的前面或后面看上去的方位。v型是指气缸排成类似v型的两排。立式内燃机的多个气缸垂直排成一排。卧式对置内燃机的气缸水平对置。倾斜式内燃机的气缸排成类似半个v型的一排。倾斜式内燃机的车篷可以设计的更低。 n now browse paragraph five in 3 minutes, please.paragraph :n number of cylinders:n the number of cylinders is often used in combination with the engine block geometry (

38、v6, slant four, inline four.) the number of cylinders is an indication of how smooth the car engine will run. an eight-cylinder engine will run smoother than a four-cylinder engine since power strokes occur with greater frequency. the number of cylinders also contributes to power output; more cylind

39、ers, more power. however, this is not always a good indicator of power output. a turbocharged, four-cylinder engine can produce more power than a normally aspirated six-cylinder engine. n 气缸数目分类法常常与气缸排列方式分类法联合使用（如v型6缸、倾斜型4缸和立式4缸）。气缸的数目可以指示出汽车发动机运行的平稳性。8缸内燃机比4缸内燃机的工作冲程间隔短，故运行更平稳。气缸的数目还与输出功率有关，气缸越多，内燃

40、机输出的功率就越大，但这也不是绝对的。一个涡轮增压4缸发动机有可能比通常的吸气式的6缸发动机输出的功率还大。n now please have a glance at paragraph six in 2 minutes.paragraph :n ignition type:n two methods for igniting fuel are used, spark ignition and compression ignition. gasoline car engines use spark ignition whereas diesel engines use compression

41、ignition. this method compresses the air to the point where the resulting rise in temperature causes ignition to occur when diesel fuel is added.n 按点火方式可分为两种：火花点火和压缩点火。汽油机使用火花点火，而柴油机使用压缩点火。压缩点火方式是指添加柴油时压缩空气使温度升高到柴油的燃点而使柴油燃烧。section ： exercisesn now its time to do the exercises. and please finish the

42、m in five minutes.n this is the end for lesson 22.n it will be greatly appreciated if you could review lesson 21&22 and preview lesson 23 in your leisure time.lesson 23 manual transmission in automobilen 词汇讲解n 课文分析n 练习答案本课教学目标：1. 了解什么是手动变速器；2. 掌握与变速器相关的专业词汇。section ： words and phasesn having a g

43、lance at the new words table, youll find every word is very professional.n how to remember these words and phrases rapidly?q there is no short-cut. q the only way is “more practice”.n check if you have remembered all the words or not with the help of your deskmate.section ： textn at first, read the

44、first paragraph silently in 3 minutes, please.paragraph :n a manual transmission (also known as a stick shift, or standard transmission) is a type of transmission used in automotive applications. manual transmissions often feature a driver-operated clutch and a movable gear selector, although some d

45、o not. most automobile manual transmissions allow the driver to select any gear at any time, but some, such as those commonly mounted on motorcycles and some types of racing cars, only allow the driver to select the next-highest or next-lowest gear ratio. this second type of transmission is sometime

46、s called a sequential manual transmission.n 手动变速器(亦作变速杆和标准变速器)是汽车驾驶时应用的一种变速器.手动变速器通常以司机可操纵的离合器、可动的档位选择器为特征,然而也不尽然.大多数的汽车手动变速器允许司机随意选择任何档位,但某些手动变速器,如那些一般装在摩托车和某些种类的赛车上的,就只允许司机选择相临档位的齿数比。后一种的变速器有时也被称为顺序手动变速器。oral english practice :n ask your deskmate a question according to the first paragraph.n read

47、the second paragraph silently in two minutes, please.paragraph :n manual transmissions are characterized by gear ratios that are selectable by engaging pairs of gears inside the transmission. conversely, automatic transmissions feature clutch packs to select gear ratio. transmissions that employ clu

48、tch packs but allow the driver to manually select the current gear are called semi-automatic transmissions.n 手动变速器的特征参数为传动比, 通过选择变速器内部的啮合齿轮对可选择传动比.相反地,自动变速器的特点是利用离合器箱来选择传动比.既能实现自动变速又能实现手动变速的变速器叫做半自动变速器。oral english practice :n ask your deskmate a question according to the second paragraph.n flip thr

49、ough the third paragraph in two minutes, please.paragraph :n contemporary automotive manual transmissions are generally available with four to six forward gears and one reverse gear, although manual transmissions have been built with as few as 2 and as many as 7 gears. some manuals are referred to b

50、y the number of forward gears they offer (e.g., 5-speed) as a way of distinguishing between automatic or other available manual transmissions. similarly, a 5-speed automatic transmission is referred to as a 5-speed automatic.n 手动变速器可有二至七个档位，但当代的汽车手动变速器通常采用四至六个前进档和一个倒档. 手动变速器根据前进档的个数来命名(如5档),以区分自动变速器

51、和其他的手动变速器.类似的,5档自动变速器被简称为5档自动.oral english practice :n one student stand up to ask a question according to the third paragraph.n another give an answer.n now well come to paragraph four and five, please read the it silently in 2 minutes,.paragraph :n other types of transmission in mainstream automot

52、ive use are the automatic transmission, semi-automatic transmission, and the continuously variable transmission7.n 主流汽车上使用的其它类型变速器有自动变速器、半自动变速器和无级变速器。 paragraph :n the image（fig.6.4） below shows the most common five-speed layout found in the usa and the uk.n 下图所示为美国和英国最常见的5档变速器的布局.n now browse parag

53、raph six in 2 minutes, please.paragraph :n this layout is reasonably intuitive because it starts at the upper left and works top to bottom, left to right, with reverse far away and toward the rear of the car. there is usually a mechanism that only allows selection of reverse from the neutral positio

54、n, so reverse will be less likely to be accidentally chosen when downshifting from 5th to 4th (or by someone used to a 6-speed transmission and trying to shift from 5th to the non-existent 6th).n 这种布局显然是合理的,因为该布局从左上角开始,自上而下,自左而右,退档布置在汽车后部,不易误操作.还有一种常用的结构是从空挡位置选择退档,这样就尽可能避免在从5档换到4档的时候错选了退档(或被一个用惯了6级变

55、速器的人从5档换到并不存在的6档)oral english practice :n one student ask a question according to the sixth paragraph.n another give an answer.n now please have a glance at paragraph seven in 2 minutes.paragraph :n manual transmissions typically offer better fuel economy than automatics. increased fuel economy with

56、 a properly operated manual transmission vehicle versus an equivalent automatic transmission vehicle can range from 5% to about 15% depending on driving conditions and style of driving - extra urban or urban (highway or city).n 手动变速器通常比自动变速器有更好的节油性.依行车条件和驾驶风格的不同(郊区或城区,路况),手动变速器汽车比同规格的自动变速器汽车节油5%到15%

57、。oral english practice :n one student ask a question according to the seventh paragraph.n another give an answer.n now please have a glance at paragraph eight in 2 minutes.paragraph :n maintenance of manual transmissions:n because clutches use changes in friction to modulate the transfer of torque between engine and transmission（fig.6.5）, they are subject to wear10 in everyday use. a very good clutch, when used by an expert driver, can last hund