汽车专业英语U1-L1(发动机部分)ppt课件.ppt

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1、1汽车的四大组成部分汽车的四大组成部分2车身车身发动机发动机底盘底盘电器系统电器系统英语怎么表示？3enginechassisbodyelectrical system图示：图示：The basic components of an automobile 3.车 身2.底 盘1.发动机4.电气系统4例句分析： There are four basic components of the There are four basic components of the automobile : engine , chassis , body and automobile : engine , cha

2、ssis , body and electrical system .electrical system . 中文：中文：basic component - basic component - 基本基本组组成成； 问题问题：汽：汽车车共四共四个组个组成部分：成部分：_、 _、_ _ _ 。engine 发动机发动机chassis 底盘底盘body 车身车身electrical system 电气系统电气系统5The Question (问题问题) Which is called the “heart” of Automobile?be called of - (be called of - (

3、被叫做被叫做-)-)；中文：哪部分被称作是汽车的心脏？中文：哪部分被称作是汽车的心脏？heart (heart (心脏心脏) )；发动机发动机6Part one Automobile Engine 汽车发动机汽车发动机一、发动机的分类一、发动机的分类 Clissified by fuel（按燃料不同分类）（按燃料不同分类）汽油机汽油机和和柴油机柴油机； Clissfiled by working progress（按工作行程分（按工作行程分类）类）四冲程四冲程发动机和发动机和二冲程二冲程发动机；发动机； Clissfiled by cooled ways（按冷却方式分类）（按冷却方式分类）水冷

4、水冷发动机和发动机和风冷风冷发动机发动机； Clissfiled by number of cylinder（按气缸数量分（按气缸数量分类）类）单缸单缸发动机和发动机和多缸多缸发动机发动机7Clissified by fuel（按燃料不同分类）8汽油发动机汽油发动机gasoline enginegasolinegslin n. 汽油汽油 点燃方式（点燃式）9柴油发动机柴油发动机diesel enginedieseldi:zl n. 柴油柴油 ，柴油，柴油机机点燃方式（压燃式）Clissfiled by working progress（按工作行程分类）（按工作行程分类）10二冲程发动机二冲程发

5、动机Two stroke enginestrokestrk n. 冲程，行程；冲程，行程；活塞反复运动一次，曲轴转动一周，两个冲程完成一个工作循环。11四冲程发动机四冲程发动机Four stroke enginestrokestrk n. 冲程，行程；冲程，行程；活塞反复运动两次，曲轴转动两周，四个冲程完成一个工作循环。12四冲程发动机的四大行程四冲程发动机的四大行程进气行程进气行程 intake stroke排气行程排气行程 exhaust stroke压缩行程压缩行程 compression stroke做功行程做功行程 working stroke13Exhaust排放排放Intake

6、进气进气 Compression压缩压缩Power/working做功做功Stroke . /struk / n. 打击；中风；笔画；冲程；尝试；轻抚打击；中风；笔画；冲程；尝试；轻抚 发动机的四大工作行程14水冷却式发动机水冷却式发动机Water coolet engine水箱，通过水泵作用，水通过水道流通整个汽缸体，进行降温。Clissfiled by cooled ways（按冷却方式分类）（按冷却方式分类）15风冷却式发动机风冷却式发动机air coolet engine风冷，通过空气气流与风扇作用，空气/风通过发动机整个汽缸体，进行降温。Clissfiled by number of

7、 cylinder（按气缸（按气缸数量分类）数量分类）16单缸发动机单缸发动机Single cylinder enginecylinder slnd n. 气缸我只有一个气缸，我只有一个气缸，一组气门；一组气门；17多缸发动机多缸发动机Multi cylinder enginecylinder slnd n. 气缸气缸我有多个气缸，我有多个气缸，多组气门；多组气门；二、发动机的基本组成18汽油机包含几大系统？ 冷却系 cooling system 润滑系 lubrication system 起动系 starting system 点火系 ignition system 燃油供给系 fuel

8、supply system 进气系统 intake system 排气系统 exhaust system1920Cooling system (冷却系统冷却系统)Starting system (起动系统起动系统)21vLubrication system (润滑系统润滑系统)vIgnition system (点火系统点火系统)22vFuel supply system (燃油供给系统燃油供给系统)vintake system (进气系统进气系统)例句分析： Engine system includes ：_、_、_、_. 中文：include vt.包括，包含； 译文：发动机系统包括：_、

9、 _、_、 _。 23ignition systemstarting systemlubrication systemcooling system点火系统点火系统起动系统起动系统润滑系统润滑系统冷却系统冷却系统汽油机包括哪两大系统？24Crank-connecting rod mechanism曲曲 柄柄连杆连杆机构机构配气机构25Valve mechanism气气 门门机机 构构 三、发动机的四大工作行程26Intake 进气进气 Compression压缩压缩Exhaust排放排放Power做功做功Stroke . /struk / n. 打击；中风；笔画；冲程；尝试；轻抚打击；中风；笔画

10、；冲程；尝试；轻抚 27 一台汽车发动机往往具有3个以上的汽缸，对于汽车发动机主要的分类方式是根据汽缸的布局及排列方式来划分。一般有直列L型、V型、W型以及水平对置B型等几种。28直列发动机(Line Engine)29V型排列六缸发动机(V-shape)30W型发动机(W-shape)31水平对置发动机水平对置发动机(Horizontally Opposed四、发动机的布置形式32发动机前置发动机前置前轮驱动前轮驱动发动机前置发动机前置后轮驱动后轮驱动发动机后置发动机后置后轮驱动后轮驱动33Engine is a self-contained power unit which convert

11、s heat energy of fuel into mechanical energy for moving the vehicle. All automobile engines, both gasoline and diesel, are classified as internal combustion engines because the combustion or burning that creates energy takes place inside the engine. In the internal combustion engine, air-fuel mixtur

12、e is introduced into a closed cylinder where it is compressed and then ignited. The burning of the fuel causes a rapid rise in cylinder pressure which is converted to useful mechanical energy by the piston and crankshaft （Fig.1-1）.Text:One.The Internal Combustion Engine34The majority of engines in m

13、otor vehicles today are four-stroke piston engine. These four strokes are intake stroke, compression stroke, power stroke and exhaust stroke. 35Two. Four Strokes1The Intake StrokeThe intake stroke begins with the piston at the Top Dead Center （TDC）. The crankshaft rotates through the connecting rod,

14、 forces the piston to move downward. This downward movement of the piston creates a vacuum, a difference in pressure, in the space above the piston. 36. Camshaft forces the intake valve open automatically at or slightly before the piston starts down. The air-fuel mixture is drawn into the cylinder.

15、At the same time, the exhaust valve remains closed during this downward movement. This valve closure prevents the entering air-fuel charge from escaping through the exhaust port. After the piston reaches the Bottom Dead Center （BDC） of its first stroke, the cylinder is practically full of an air-fue

16、l charge. The drawing of an air-fuel charge into the cylinder in this manner, during the downward movement of the piston, constitutes the intake stroke （Fig.1-2a372The Compression StrokeAfter piston reaches the BDC, the intake valve closes and the exhaust valve remains closed. The piston is beginnin

17、g to move upward again, compresses the trapped air-fuel mixture that was brought in by the intake stroke. As piston reaches the TDC again during its upward travel, the compression stroke of the piston is over（Fig.1-2b）.383The Power StrokeNow, both valves remain closed during the power stroke. Before

18、 piston reaches the TDC on the compression stroke, the spark plug fires, igniting the compressed air-fuel mixture which produces a powerful expansion of the vapor. The combustion process pushes the piston down the cylinder with great force turning the crankshaft to provide the power to propel the ve

19、hicle （Fig.1-2c）.394The Exhaust StrokeNear the end of the downward movement of the power stroke, the camshaft opens the exhaust valve, but the intake valve remains closed. Although much of the gas pressure has expended itself driving the piston downward, some pressure still remains when the exhaust

20、valve opens. So, this remaining pressurized gas flows comparatively free from the cylinder through the passage opened by the exhaust valve. 40Then, as the piston again moves up in the cylinder, it drives any remaining gases out of the cylinder past the open exhaust valve. As the piston travels throu

21、gh the TDC position and starts downward again in the cylinder, a new operating cycle begins. This four strokes are continuously repeated in every cylinder as long as the engine remains running （Fig.1-2d）.41The single-cylinder engine just described as above provides only one power stroke during every

22、 two crankshaft revolutions or delivers power only one-fourth of the time. To provide a more even and continuous flow of power, automobile have engines with four, six, eight or twelve cylinders.Three. The Multiple-cylinder Engine42Four. The Classification of the EngineFor identification purposes, ma

23、nufacturers classify automobile engines by their cylinder arrangement, valve arrangement, and type of cooling system.Automobile engines have their cylinders arranged in four distinct ways：in-line, V-shape, W-shape, or horizontally opposed （Fig.1-3）.43Automobile engines have their valves arranged in

24、one of three ways：the valves in the engine block; one valve in the cylinder head and the other in the engine block; both valves in the cylinder head. Modern automotive engines utilize the third type of valve arrangement.Manufacturers also classify engines as being either air-cooled or water-cooled.

25、课堂小结 需要记住的单词：需要记住的单词： 发动机发动机 底盘底盘 车身车身 电器系统电器系统 汽油汽油 柴油柴油 冲程冲程44EngineEngineChassisChassisBodyBodyElectrical systemElectrical systemGasolineGasolineDieselDieselstrokestroke4546 单独的，独立的单独的，独立的 气缸气缸 曲柄连杆机构曲柄连杆机构 配气机构配气机构 润滑系统润滑系统 点火系统点火系统 启动系统启动系统 冷却系统冷却系统 进气系统进气系统 排气系统排气系统47SingleSinglecylindercylind

26、erCrank-connecting rod machanismCrank-connecting rod machanismValve machanismValve machanismLubrication systemLubrication systemIgnition systemIgnition systemStarting systemStarting systemCooling systemCooling systemIntake systemIntake systemExhaust systemExhaust system需要记住的句子 There are four basic c

27、omponents of the automobile : engine , chassis , body and electrical system . 译：汽车有四个基本组成部分，发动机， 底盘，车身和电气系统。 Engine system includes ： ignition system，lubrication system, cooling system, starting system. 译：发动机系统包括：点火系，润滑系，冷却系，起动系。48布置任务 将需要记住的单词和句子记录在笔记本上； 将需要记住的单词每个写3遍，1遍汉语意思； 完成教材p7课后习题； 预习第二节课的内容；4950