2022年汽车的构造 .pdf

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1、Structure of automobile In order to study automobiles,it is important to review the basic parts of an automobile.An automobilecan be snbdivided into several major categories:the body and frame,the engine or power source,the chassis and the electrical equipment. Body and Frame The body and frame sect

2、ion of an automobile is the basic foundation of the vehicle.All other components and systems are attached to the body and frame.The frame supports the wehicle body,engine,and the driveline. There sre two types of body and frame configuration.The separate body and frame construction illustrated in Fi

3、g.1-a) has been used for a long time.The second type pf cpnstruction is called the unitized body.See Fig 1-2b).The type of vehicle is designed with the frame and body in one unit.The unitized body is used in most cars today. Engine The engine is used to power the vehicle.The engine is also called th

4、e power source or motor.The word motor is defined as that which imparts motion.So a motor can be any device that produces power.However,the power source in the automobile is usually referred to as the engine. Most automobiles use the gasoline engine as a power source.However ,other power sources are

5、 being tested and introduced every year.For example,the diesel engine is alsobeing used as a power source today,and has been used in commercial vehicles widely.In addition,some automotive engineers predict the use of gas turbines and Stifling engines for future power sources in the automobile. Most

6、automobiles use the reciprocating piston or Otto cycle engine.However,certain car manufactures also offer rotary design engines as an optional power source.Although the rotary engine now used on certain vehilces looks similar to the reciprocating piston engine,internally there many differences. The

7、engine is typically located in the front of the vehicle.But some vehicles have rear engines.In addition,certain manufactures have developed engines that are placed in the middle of the body and frame. Most of engines are desined to have several supporting technical systems.These include:the fuel sys

8、tem,the ignition system,the starting and charging system,the lubricating system,the cooling system,the air intake and exhaust system,the pollution control system. The fuel system is designed to mix the air and fuel in the engine.This mix will produce an efficient combustion process.The ignition syst

9、em is designed to ignite the air and fuel that has been mixed.The starting and charging system is designed to start the engine and to keep the battery charged during operation.The lubricating system is designed to keep all engine moving parts lubricated so that friction is reduced internally.The coo

10、ling system is designed to keep the engine at the most engine efficient operating temperature. The air intake system is designed to get air into the engine efficiently and without dirt.The exhaust system is designed to clean the exhaust gases and to reduce various emissions from the engine including

11、 carbon monoxide,nitorgen oxide (oxides of nitrogen),and hydrocarbons. ChassisThe chassis consists of transmission,the running gear and the suspension system.It is shown in Fig.1-3. The transmission is defined as those components that transmit the power from the engine to 名师资料总结 - - -精品资料欢迎下载 - - -

12、- - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 1 页，共 3 页 - - - - - - - - - the wheels.This action will propel the vehicle in a forward or reverse direction.The transmission includes components such as the clutch,gearbox,drive shaft,differential,and halfshafts etc. There are two methods in whic

13、h the transmission can be designed: the rear wheel driveline system and the front wheel driverline system.In rear wheel driveline system,the engine is in the front of th body and frame.The power is then transmitted to the rear of vehicle for propulsion.The front wheel driveline system is used on mos

14、t cars today.In this system the engine is in the front of the vehicle.The driveline can be also in the front of a vehicle.Both systems have advantages and disadvantages and are equally reliable in their opearation.The running gear consists of wheels,tires,braking system and steering system.The braki

15、ng system is used to reduce the speed of the vehicle and hold it stationary as necessary.The steering system is used to provise the means by which the vehicle is directionally turned. The suspension system on the automobile includes such components as the springs,shock absorbers,struts,torsion bars,

16、axles,and connecting linkages.These components are designed to support the body and frame,the engine,and the drivleine on the board.Without suspension system,the comfort and case of driving would be reduced.The springs and torsion bars are attached to the axles of the vehicle.The two types of spring

17、s commonly used are leat spring and coil spring.Torsion bars are made of long spring steel roads.One end of the rod is connected to the frame,while the other end is connected to the movable parts of the axles.As the axles move up and down,the rod is twisted and acts as a spring.Shock absorbers sre u

18、sed to slow down the upward and downward movement of the vehicle.This action occurs when the car goes over a rough road.The axles and connecting linkages are those components that connect the springs,torsion bars,and shock absorbers to the vehicle frame and to the wheels. Electrical Equipment The el

19、ectrical equipment comprises mainly the battery,althernator,lights,instrumentation,electrical devices and electronic control systems etc. 第一课汽车的构造为了研究汽车，了解汽车的基本组成是非常重要的。如图1-1，汽车被分为几大主要部分：车身和车架，发动机或动力源，底盘和电气设备。车身和车架车身和车架是汽车的基本构成部分。其他所有部件和系统都与车身和车架相连。车架支撑着车身、发动力、传动系、行驶系。典型车辆车身和车架如图1-2 所示。车身和车架的结构有两种类型

20、，分离式车身和车架已使用了很长时间，如图 1-2a） 所示。第二种被称为整体式车身，车辆的车身和车架设计成一体，如图1-2b）所示。整体式车身在今天的大多轿车中使用。发动机发动机为汽车提供动力，因此发动机又被称为动力源或马达。马达是产生运动的源泉，因此马达可以使提供动力的任何装置，但是，汽车的动力源通常是指发动机。大多数汽车使用汽油发动机作为动力源，但是每年都有其他动力源被试验和引进。比如，今天的柴油发动机也被当做动力源，已经广泛用于商用车。另外没有写汽车工程师预测将来燃气轮机和斯特林发动机也将被作为汽车的动力源。许多汽车使用往复活塞式或奥托循环发动机，但是， 有些汽车制造商提供转子式发动机作

21、为任选的动力源。 虽然现在某些汽车使用的转子式发动机与活塞往复式发动机看起来转子式相似，但本质上有许多不同。名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 2 页，共 3 页 - - - - - - - - - 发动机一般置于汽车的前部，但是有一些汽车采用后置发动机。另外还有一些制造商已开发了中置发动机及发动机置于车身和车架的中部。绝大多数发动机都有几个专门的系统，包括： 燃料供给系统、点火系统、 起动和充电系统、润滑系统、冷却系统、进气和排气系统、排放控制系统。燃料供给系统在发动机

22、内将空气和燃油混合，混合气将产生搞笑的燃烧过程。点火系统的作用是将混合的空气和燃油点燃。起动和充电系统的作用是起动发动机和在运行期间为蓄电池充电。 润滑系统的作用是保持发动机运动件之间的润滑，减少内部摩擦。 冷却系统的作用是保持发动机在搞笑的运行温度下工作。进气系统的作用是使结晶的空气高效地静如发动机，排气系统的作用是排除废气、减少排气噪声。 排放控制系统的作用是减少发动机各种排放物，包括CO、NOX和 HC。底盘底盘是由传动系统、行驶系统、悬架组成，如图1-3 所示。传动系统是那些将发动机动力传给车轮的不见，其作用是驱动汽车前进或倒车。传动系统包括离合器、变速器、传动轴、差速器和半轴等。传动

23、系统有两种设计方法：后轮驱动和前轮驱动系统。后轮驱动系统， 发动机置于车身和车架前部， 动力传到汽车后轴产生驱动。目前许多车使用前轮驱动系统，这种系统发动机置于汽车前部， 传动装置也在前部。这两种系统都各自存在优缺点，运行时可靠性相差不大。行驶系统由车轮、轮胎和控制汽车的制动系统、转向系统组成。 制动系统用老使车辆减速，必要时使车辆保持静止。转向系统用来实现车辆转向。汽车的悬架系统包括悬架弹簧、减振器、导向机构、扭力杆、车轴、链接装置。这些部件的作用是支撑车身和车架、发动机、连接装置。没有悬架系统，乘坐的舒适性就会变差。弹簧和扭力杆与车桥相连，常用的两种弹簧：钢板弹簧和螺旋弹簧。扭力杆由长弹簧钢棒制成，一段与车架相连，而另一端与车桥的活动部件相连。随着车轴上下活动，钢管被扭转弹簧起作用。减振器的作用是缓冲汽车的上下振动，这种作用在恶劣的行驶条件下就发挥出来。车桥和链接装置是将弹簧、扭力杆、减振器、与车架和车轮连接的那些部件。电气设备电器设备主要包括蓄电池、交流发电机、灯光、仪表、电动装置和电子控制系统等。名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 3 页，共 3 页 - - - - - - - - -