机械专业英语21~24章

Introduction to Automobile⏹词汇讲解⏹课文分析⏹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 Ⅰ：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 thespecial word s you can’t understand.1. 重点专业名词解析⏹differential⏹suspension⏹transmission⏹driving axle & driving shaftdifferential⏹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”？⏹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以纯滚动的形式作不等距行驶，减少轮胎与地面的摩擦。

suspension⏹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。

⏹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。

transmission⏹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。

driving axle & driving shaft⏹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。

⏹ignition n →ignite vt 点燃；激起vi 着火⏹lubrication n →lubricate vt 使润滑vi 起润滑作用⏹cylinder n →cylindrical adj 圆柱形的⏹intermittent adj →intermission n 间歇，休息时间；intermittence n断续性，周期性⏹compensate v →compensation n补偿，补偿金，报酬❑Did you get any compensation when you were dismissed from your job?❑The job is hard but the compensation is good.3. 专业名词的通用含义⏹differential n 差别，差速器；adj 差别的⏹muffler n 消声器，围巾，厚手套⏹tire n 轮胎；vt 使疲劳；vi 疲劳，厌烦（+of）❑She never tires of talking about her hometown.⏹transmission n 变速器，传送，传播❑the transmission of diseases⏹manifold n 多种，管；adj 种种的❑manifold duties⏹Now please read the new words after me for 2 times.⏹After that, you will have 10 minutes to remember as many words as you can.Section Ⅱ：text⏹At first, read the first paragraph silently in two minutes, please.paragraph Ⅰ:⏹Automobile（Fig.6.1）is a self-propelled vehicle used for travel on land. The term iscommonly applied to a four-wheeled vehicle designed to carry two to six passengers anda limited amount of cargo, as contrasted with (与...比较) a truck, which is designedprimarily 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.⏹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 :⏹Please describe the functions of an automobile, a truck and a bus separately!⏹Read the second paragraph silently in two minutes, please.paragraph Ⅱ:⏹Differential, fuel injection, 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.⏹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性和技术特性。

paragraph Ⅲ:⏹Differential and fuel injection system are introduced in this lesson, with other componentspresented in the following lessons.⏹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。

⏹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 deep 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 large book under his arm.他夹着本厚书，走出了图书馆。

⏹Now we’ll come to paragraph four, the most difficult one in this passage, please read theit silently in 5 minutes,.paragraph Ⅳ:⏹Differential in the automobile is a set of gears used on the driving axle. The two wheelson the driving axle must be interconnected 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).⏹汽车差速器由装在驱动桥上的一套的齿轮组成。