汽车专业英语2版参考译文-20180227-2

附录1外文翻译Automobile Brake SystemThe braking system is the most important system in cars. If the brakes fail, the result can be disastrous. Brakes are actually energy conversion devices, which convert the kinetic energy (momentum) of the vehicle into thermal energy (heat).When stepping on the brakes, the driver commands a stopping force ten times as powerful as the force that puts the car in motion. The braking system can exert thousands of pounds of pressure on each of the four brakes.Two complete independent braking systems are used on the car. They are the service brake and the parking brake.The service brake acts to slow, stop, or hold the vehicle during normal driving. They are foot-operated by the driver depressing and releasing the brake pedal. The primary purpose of the brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by when a separate parking brake foot pedal or hand lever is set.The brake system is composed of the following basic components: the “master cylinder” which is located under the hood, and is directly connected to the brake pedal, converts driver foot’s mechanical pressure into hydraulic pressure. Steel “brake lines” and flexible “brake hoses”connect the master cylinder to the “slave cylinders” located at each wheel. Brake fluid, specially designed to work in extreme conditions, fills the system. “Shoes” and “pads” are pushed by the slave cylinders to contact the “drums” and “rotors” thus causing drag, which (hopefully) slows the car.The typical brake system consists of disk brakes in front and either disk or drum brakes in the rear connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder (Figure).Basically, all car brakes are friction brakes. When the driver applies the brake, the control device forces brake shoes, or pads, against the rotating brake drum or disks at wheel. Frictionbetween the shoes or pads and the drums or disks then slows or stops the wheel so that the car is braked.In most modern brake systems (see Figure 15.1), there is a fluid-filled cylinder, called master cylinder, which contains two separate sections, there is a piston in each section and both pistons are connected to a brake pedal in the driver’s compartment. When the brake is pushed down, brake fluid is sent from the master cylinder to the wheels. At the wheels, the fluid pushes shoes, or pads, against revolving drums or disks. The friction between the stationary shoes, or pads, and the revolving drums or disks slows and stops them. This slows or stops the revolving wheels, which, in turn, slow or stop the car.The brake fluid reservoir is on top of the master cylinder. Most cars today have a transparent r reservoir so that you can see the level without opening the cover. The brake fluid level will drop slightly as the brake pads wear. This is a normal condition and no cause for concern. If the level drops noticeably over a short period of time or goes down to about two thirds full, have your brakes checked as soon as possible. Keep the reservoir covered except for the amount of time you need to fill it and never leave a cam of brake fluid uncovered. Brake fluid must maintain a very high boiling point. Exposure to air will cause the fluid to absorb moisture which will lower that boiling point.The brake fluid travels from the master cylinder to the wheels through a series of steel tubes and reinforced rubber hoses. Rubber hoses are only used in places that require flexibility, such as at the front wheels, which move up and down as well as steer. The rest of the system uses non-corrosive seamless steel tubing with special fittings at all attachment points. If a steel line requires a repair, the best procedure is to replace the compete line. If this is not practical, a line can be repaired using special splice fittings that are made for brake system repair. You must never use copper tubing to repair a brake system. They are dangerous and illegal.Drum brakes, it consists of the brake drum, an expander, pull back springs, a stationary back plate, two shoes with friction linings, and anchor pins. The stationary back plate is secured to the flange of the axle housing or to the steering knuckle. The brake drum is mounted on the wheel hub. There is a clearance between the inner surface of the drum and the shoe lining. To apply brakes, the driver pushes pedal, the expander expands the shoes and presses them to the drum. Friction between the brake drum and the friction linings brakes the wheels and the vehicle stops. To release brakes, the driver release the pedal, the pull back spring retracts the shoes thus permitting free rotation of the wheels.Disk brakes, it has a metal disk instead of a drum. A flat shoe, or disk-brake pad, is located on each side of the disk. The shoes squeeze the rotating disk to stop the car. Fluid from the master cylinder forces the pistons to move in, toward the disk. This action pushes the friction pads tightly against the disk. The friction between the shoes and disk slows and stops it. This provides the braking action. Pistons are made of either plastic or metal. There are three general types of disk brakes. They are the floating-caliper type, the fixed-caliper type, and the sliding-caliper type. Floating-caliper and sliding-caliper disk brakes use a single piston. Fixed-caliper disk brakes have either two or four pistons.The brake system assemblies are actuated by mechanical, hydraulic or pneumatic devices. The mechanical leverage is used in the parking brakes fitted in all automobile. When the brake pedal is depressed, the rod pushes the piston of brake master cylinder which presses the fluid. The fluid flows through the pipelines to the power brake unit and then to the wheel cylinder. The fluidpressure expands the cylinder pistons thus pressing the shoes to the drum or disk. If the pedal is released, the piston returns to the initial position, the pull back springs retract the shoes, the fluid is forced back to the master cylinder and braking ceases.The primary purpose of the parking brake is to hold the vehicle stationary while it is unattended. The parking brake is mechanically operated by the driver when a separate parking braking hand lever is set. The hand brake is normally used when the car has already stopped. A lever is pulled and the rear brakes are approached and locked in the “on” position. The car may now be left without fear of its rolling away. When the driver wants to move the car again, he must press a button before the lever can be released. The hand brake must also be able to stop the car in the event of the foot brake failing. For this reason, it is separate from the foot brake uses cable or rods instead of the hydraulic system.Anti-lock Brake SystemAnti-lock brake systems make braking safer and more convenient, Anti-lock brake systems modulate brake system hydraulic pressure to prevent the brakes from locking and the tires from skidding on slippery pavement or during a panic stop.Anti-lock brake systems have been used on aircraft for years, and some domestic car were offered with an early form of anti-lock braking in late 1990’s. Recently, several automakers have introduced more sophisticated anti-lock system. Investigations in Europe, where anti-lock braking systems have been available for a decade, have led one manufacture to state that the number of traffic accidents could be reduced by seven and a half percent if all cars had anti-lock brakes. So some sources predict that all cars will offer anti-lock brakes to improve the safety of the car.Anti-lock systems modulate brake application force several times per second to hold the tires at a controlled amount of slip; all systems accomplish this in basically the same way. One or more speed sensors generate alternating current signal whose frequency increases with the wheel rotational speed. An electronic control unit continuously monitors these signals and if the frequency of a signal drops too rapidly indicating that a wheel is about to lock, the control unit instructs a modulating device to reduce hydraulic pressure to the brake at the affected wheel. When sensor signals indicate the wheel is again rotating normally, the control unit allows increased hydraulic pressure to the brake. This release-apply cycle occurs several time per second to “pump” the b rakes like a driver might but at a much faster rate.In addition to their basic operation, anti-lock systems have two other things in common. First, they do not operate until the brakes are applied with enough force to lock or nearly lock a wheel. At all other times, the system stands ready to function but does not interfere with normal braking. Second, if the anti-lock system fail in any way, the brakes continue to operate without anti-lock capability. A warning light on the instrument panel alerts the driver when a problem exists in the anti-lock system.The current Bosch component Anti-lock Braking System (ABSⅡ), is a second generation design wildly used by European automakers such as BWM, Mercedes-Benz and Porsche. ABSⅡsystem consists of : four wheel speed sensor, electronic control unit and modulator assembly.A speed sensor is fitted at each wheel sends signals about wheel rotation to control unit. Each speed sensor consists of a sensor unit and a gear wheel. The front sensor mounts to the steering knuckle and its gear wheel is pressed onto the stub axle that rotates with the wheel. The rear sensor mounts the rear suspension member and its gear wheel is pressed onto the axle. The sensor itself is a winding with a magnetic core. The core creates a magnetic field around thewinding, and as the teeth of the gear wheel move through this field, an alternating current is induced in the winding. The control unit monitors the rate o change in this frequency to determine impending brake lockup.The cont rol unit’s function can be divided into three parts: signal processing, logic and safety circuitry. The signal processing section is the converter that receives the alternating current signals form the speed sensors and converts them into digital form for the logic section. The logic section then analyzes the digitized signals to calculate any brake pressure changes needed. If impending lockup is sensed, the logic section sends commands to the modulator assembly.Modulator assemblyThe hydraulic modulator assembly regulates pressure to the wheel brakes when it receives commands from the control utuit. The modulator assembly can maintain or reduce pressure over the level it receives from the master cylinder, it also can never apply the brakes by itself. The modulator assembly consists of three high-speed electric solenoid valves, two fluid reservoirs and a turn delivery pump equipped with inlet and outlet check valves. The modulator electrical connector and controlling relays are concealed under a plastic cover of the assembly.Each front wheel is served by electric solenoid valve modulated independently by the control unit. The rear brakes are served by a single solenoid valve and modulated together using the select-low principle. During anti-braking system operation, the control unit cycles the solenoid valves to either hold or release pressure the brake lines. When pressure is released from the brake lines during anti-braking operation, it is routed to a fluid reservoir. There is one reservoir for the front brake circuit. The reservoirs are low-pressure accumulators that store fluid under slight spring pressure until the return delivery pump can return the fluid through the brake lines to the master cylinder.译文汽车制动系统制动系统是汽车中最重要的系统。

第二章内燃机** 工作原理使用煤气作燃料、成功地以四冲程工作循环进行工作的最早的内燃机由尼古拉斯·奥古斯特·奥托于1876年研制成功。

奥托是一位在道依茨公司（许多年来，一直是世界上最大的内燃机制造商）工作的自学成才的德国工程师。

奥托的助手之一戈特利布·戴姆勒后来研制成功了一台使用汽油的发动机，1885年的4315号专利对该发动机进行了描述。

戴姆勒首次将这种发动机用于汽车上。

汽油机将空气与汽油的可燃混合气吸入气缸，当这些混合气得到压缩后，通过一个定时的火花将可燃混合气点燃。

因此，这样的发动机有时也被称为点燃式（S.I.）发动机。

为了完成一个工作循环，这些发动机的活塞需要走过四个行程：离开气缸盖向外运动，从而吸入空气与燃油的进气行程；向里朝向气缸盖运动，从而使混合气得到压缩的压缩行程；向外运动的做功行程以及向里的排气行程。

进气行程。

进气门开启，排气门关闭。

活塞下行，离开气缸盖（见图2-1a）。

活塞沿着气缸的快速运动导致了压力降低或叫做低压。

在该行程完成三分之一时，此低压会达到低于大气压力约0.3巴的最大值。

实际上产生的低压将取决于发动机的转速和负荷，而一个典型的平均值为低于大气压力0.12巴。

这个低压会将按照10~17份空气与1份汽油的比例（重量比）进行混合的新鲜空气与雾化汽油的混合物吸入气缸。

一种利用缸内低压来实现进气的发动机被称为“通常进气”或“自然吸气”式发动机。

压缩行程。

进、排气门都关闭。

活塞开始上行，朝向气缸盖运动（见图2-1b）。

在活塞达到最内的位置时，进入气缸的混合气会被压缩到原始气缸容积的1/8~1/10。

这种压缩使空气和雾化的汽油分子会靠的更近，并且不仅提高了缸内气体压力，而且还提高了温度。

一般，在节气门全开、发动机运转在大负荷下，最大的气缸压缩压力范围在8~14巴之间。

做功行程。

进、排气门全关闭，并且就在活塞到达压缩行程的上止点之前，火花塞将浓可燃混合气点燃（见图2-1c）。

UNIT TWO P18An automobile probably has about 7,000 different parts in it. Some of them make it more comfortable or better looking, but most of them are to make it run.一台车可能有７０００多个不同的零件。

一些使它更舒适或外观更好看。

但大部分是使它能运转的。

The three basic components of the automobile are the engine, chassis and body.汽车基本三大组成部分是发动机，底盘和车身．The engine converts the fuel energy into mechanical power. An internal combustion engine powers our modern automobile. The engine burns its fuel within the engine proper, as compared to a steam engine where the fuel is burned externally. The gasoline and air mixture of the internal combustion engine is compressed by a piston inside an airtight cylinder and ignited by a spark. The trapped air-fuel mixture burns fiercely, causing tremendous heat which expands the trapped gases and pushes the piston down. This is the motive power of the automobile. The automobile engine is essentially a heat engine. It requires fuel to burn, a spark to ignite, lubrication to minimize friction, and a cooling system to dissipate unwanted heat.发动机把燃油的能量转化成机械能．内燃机给现代的汽车提供动力。

汽车工程专业英语全文翻译一当今的汽车一般都由15000多个分散、独立且相互配合的零部件组成..这些零部件主要分为四类：车身、发动机、底盘和电气设备..Body：车身Engine：发动机Brakes：制动器Power train：传动系Steering：转向系Electrical：电器及电子设备Suspension：悬架Layout of a passenger car：乘用车总布置Layout of a commercial vehicle：商用车总布置1.1 车身汽车车身是由车窗、车门、发动机罩和行李箱盖焊接在金属板外壳发动机发动机作为动力装置..最常见的发动机气缸的排列方式称为发动机配置..直列式发动机的汽缸呈一列布置..这个设计创造了一个简单的发动机缸体铸造..在车辆应用中;汽缸数一般是2-6缸;汽缸中心线与水平面垂直..当汽缸数增多时;发动机尺寸和曲轴就成为一个问题..解决这个问题的办法就是采用V形汽缸呈两列布置;且两列气缸之间夹角为V形发动机..这个设计使发动机尺寸和曲轴都变得更短且更坚硬.. 前置发动机纵向安装;既可前轮驱动也可后轮驱动..后置发动机是将发动机安装在后轮后面..发动机可横置或纵置;一般情况下为后轮驱动..1.4 电气系统电气系统为起动机、点火系统、照明灯具、取暖器提供电能..该电平由一个充电电路维护..1.4.1 充电充电系统为所有汽车电子元件提供电能..充电系统主要包括：蓄电池;交流发电机;电压调节器;即通常是交流发电机上不可或缺的;充电警告或指示灯和金属丝连成一个完整电路..蓄电池为起动提供电能;然后发动机工作;交流发电机就为所有的电子元件提供电能..同时也给蓄电池充电即用来使发动机起动..电压调节器有过充保护作用..1.4.2 起动起动系统包括：蓄电池、电缆、起动机、飞轮和换向器..起动时;有两个动作同时运行;该起动机齿轮与飞轮齿圈啮合;并起动电机;然后运行传输到发动机曲轴..起动机电机将起动机安装在发动机缸体上并由电池供电..1.4.3 点火一个基本的点火系统包括：蓄电池、低压电缆、点火线圈、线圈高压电缆、火花塞电缆和火花塞..点火系统提供高强度火花使火花塞点燃燃料室里的液体燃料..火花必须在适当的时候提供;并达到能够使燃料点燃的能量要求..这些能量从蓄电池和交流发电机获得;点火线圈使电压增高..该系统有两个电路;主电路或低压电路点燃火花;次电路或高压电路产生高压并将其分配到火花塞上.. 复习题1. 列出汽车有那几部分组成..2. 根据车身外形车辆常见类型是什么3. 向下移动的冰锥增加汽缸容积和新鲜的通过进气阀开启的空气燃料混合..2．压缩行程向上移动的活塞减少了汽缸内体积和压缩的空气燃料混合物..不久之前;香港贸易发展局是达成共识;火花塞点燃压缩空气燃料的混合物;从而启动了燃烧过程..更高的压缩比意味着更好的燃油利用率..压缩的程度受制于敲限制..3.做功行程火花点火后在火花塞点燃了压缩空气燃料的混合物;作为混合的结果温度升高..在汽缸增加;迫使活塞向下的压力..活塞转让的权力;通过连杆曲轴..4.排气行程向上移动的活塞燃烧排出的气体废气通过公开排气阀..在四冲程过完成后又周期重复..这台发动机有数以百计的其它部分..发动机的主要部件是发动机缸体;发动机头;活塞;连杆;曲轴和阀门..其他部分一起营造系统..这些系统是燃油系统;进气系统;点火系统;冷却系统;润滑系统和排气图2 - 2..这些系统都有一定的作用..这些系统将在后面详细讨论..发动机缸体是发动机的基本框架..所有其他发动机零件要么在其中的位置或固定它..其所持有的气瓶;水套和油画廊图2 - 4..发动机缸体还持有曲轴;那拴到块的底部..还装在凸轮轴块;除却架空凸轮OHC发动机..在大多数汽车;这个部件是由灰铸铁或者一种合金混合物灰铁和其它金属如镍或铬..发动机缸体是铸件..有些气缸体;特别是在小汽车里的那些;都是由铝做成的..这种金属比铁轻得多;然而;铁的耐磨性比铝好..因此;在大多数铝制发动机的气缸活塞;连杆和曲轴2.3.1 曲柄机构和能量活塞由曲柄机构和气缸;连杆组成..这些部件通过气体能量推动;从而引起这些部件产生惯性力..气能产生的力可以再细分为垂直于竖直平面的力Fn;且作用于汽缸壁;和一个推动连杆的力Fs;这个连杆的力;从而引起切向力Ft并作用于曲柄机构;这些能量要求在一起产生扭转和法向力Fr..这气体作用力分为作用角α;支点于连杆的作用角β;和压缩比入:连杆作用力: Fs=Fg/cosβ侧向力 : Fn=Fgtanβ法向力 : Fr=Fgcosα+β/ cosβ切向力 : Ft=Fg sinα+β/ cosβ所以的这些关系代表了一种方法计算各部件的振动.活塞是四个运动周期中一个重要部分;很多活塞都是从铝中提炼出来研制而成的.活塞;通过连杆传递能量来压缩点燃混合气体.这些能力转化为曲柄的动能.这样;圆形的钢圈装入汽缸;用活塞环来密封整个燃烧室.这个称为活塞环..这些用来放活塞环的称为凹槽..一个活塞销放在中间通过一个小孔固定..活塞销的作用是固定活塞于连杆之间的连接;对活塞销起作用的是活塞销凸台..活塞本身;它的环和活塞销一起称为活塞总成..1活塞为了抵抗高温的燃烧室;活塞必须非常坚固;但是也必须轻便;因为它是在气缸内高速运转而上下运动的;活塞内是空的;在顶部是厚的用来传递高温高压的气体动力;底部温度较低所以做成薄的..顶部是活塞头或活塞顶;薄部分是裙部;两节之间的凹槽称为环带..活塞顶可以是平的;凹的;圆顶的或是隐蔽的;在柴油机的燃烧可能形成完全或部分活塞冠;依靠这种方法喷射..所以活塞采用不同的形状..2..活塞环如图2-9所示;活塞环装进接近活塞顶部的环槽..简单来说;活塞环是薄的;是圆形的金属片;适合槽活塞顶部的..现在的发动机;每个活塞有三个活塞环;老式的发动机有四个甚至五个..活塞环装在活塞内表面的凹槽内..活塞环的外表面紧靠着汽缸壁活塞环提供了活塞环于汽缸壁之间的密封;也就是说;只有活塞环接触汽缸壁..顶头两个活塞环是防止气体从汽缸壁漏出的;称为压缩环..最底下的一个是防止汽油飞溅到缸桶而从间隙进入到燃烧室;所以称为油环..表面镀铬的铸铁压缩环一般用于汽车的发动机..镀铬的活塞环提供了光滑;耐磨的表面..在做功行程;燃烧室对压缩环的压力是非常大的..原因是他们朝汽缸壁方向挤开;一些高压的气体进入到活塞环;这样使得活塞环表面充分接触到汽缸壁;燃烧的气体压力使得活塞环底部紧紧地压住活塞凹槽;然而;越高的燃烧的气体压力更加紧紧地把活塞环表面和汽缸壁密封住.. 3..活塞销活塞销是用来连接活塞于连杆的..活塞销装入销孔;装入连杆最顶头的小孔..连杆的顶部应远小于连杆的尾部才能装进曲柄轴颈..小的底部装进活塞的内底部..活塞销通过一边装入活塞销;通过小的连杆一端;然后通过活塞的另一边..这使得连杆稳固地在活塞中间适当的位置..活塞销是是空心的且是高强度的钢制成的..很多销的镀铬的使得更加耐磨..连杆是高强度的钢铸造的;它通过曲柄轴颈传递力和运动从活塞到曲柄销..连杆小的一头是连接活塞销的..轴瓦是用软金属制成的;比如青铜;用来这样合成的..下级的连杆装进曲柄轴颈..这称为大头..这个轴承;是钢背的铅或者是锡壳制成的..这些是一样被用作主要轴承..大端的分离切口往往是单个的;所以它足够小可以从燃烧室中取出.. 连杆由合金钢铸成..曲轴如图2-10所示;连同连杆通过旋转而带动活塞往复运动从而带动汽车行驶..它是由碳钢和低比例的镍合成的主要的曲轴轴颈装进汽缸;大端匹配连杆..在曲轴的后端附加有飞轮;在曲轴的前端有驱动轮对应的正时齿轮;风扇;冷却水和发电机..曲轴的摆幅;i;e;是主要的轴颈和大端中心之间的距离..控制冲程的幅度;冲程是双次进行的;摆动的幅度是活塞从TDC到BDC的距离;反之亦然..单缸的发动机每两次曲轴循环只能提供单一的能量脉冲..能量只能提供四分之一的时间..当超过一个汽缸时它能从曲轴获得流动性的能量..额外的能量被均匀地隔开遍及两个转数或四冲程的一个周期..四缸的一般用于汽车..为了保持曲轴的平衡设置第一和第四的活塞是在TDC..第二和第三的活塞是在BDC每个冲程的间隔是180°;图标的序列显示了各个缸的点火顺序;点火顺序是1-3-4-2;但是这个顺序可以改变为1-2-4-3;如果安装了另外的凸轮轴.. 注意到第四个活塞总是伴随着第一活塞进行的..当第四活塞进气阀完全打开时;第一缸的活塞完全关闭;这是用来调节气门间隙的..表格飞轮有碳钢制成;装在曲轴的后端..同时带动曲轴旋转和离合器..同时传送给变速器;和启动齿圈包围着在四个冲程当中只有一个冲程是做功的所以飞轮只有在这个时间带动曲轴;发动机在这几个不做功的冲程转动..平衡器和减震器是用来保持发动机曲轴正常缓冲的..比如每个燃烧室燃烧;它能加快曲轴旋转..轴的惯性它稍稍随后;这样在曲轴上起扭转作用..连续扭转震动引起的频率不同于发动机的转速和发动机缸数..减震器减少他们的振动..减震器主要由轮毂和惯性环组成..惯性环是结合轮毂通过弹性插入的..惯性环转动是和曲轴密切相关的在燃烧室内;然而抑制其扭转;并通过曲轴控制犯低级转速..一些减震器是由两个惯性环和而且是不同的尺寸从而更好地控制其振动..使用了一段时间后;弹性体会恶化或连接件可以不要..致使减震器失效或是引起自身振动.. 损坏的必须得替换下来..减震器的设计要结合轮毂的密封轴颈..在轮毂里密封凹槽;造成石油泄漏..袖套修理可以恢复减震器如果是在良好的条件下..轮毂在一定条件下可以维修来调节衬套..2.6.1 汽油汽油是从原油中提炼石油..汽油是高度易燃的;这意味着它容易在空气容易燃烧..汽油容易蒸发..这种特性被称为波动;是重要的..但是;它不能太容易挥发;否则将转向油箱内的蒸汽..管内的燃料;燃料蒸气可能阻止液体汽油流..这就是所谓的蒸气锁..在燃料蒸气锁普遍在暴露于高温线泵的进口侧..汽油的燃烧;随其质量和添加剂比例混合的..汽油的燃烧方式在室燃烧是很重要的.增加燃烧室中的燃料混合物点火前的压力;有助于提高发动机功率..这是通过压缩到一个较小的燃料混合物体积..高压缩比;不仅有利于推力;而且也给更多的有效的动力..但更进一步的压缩比起来;敲倾向增加..辛烷值是对汽油的抗爆性的质量或在燃烧过程中能够抵抗爆炸的认定..有时被称为爆震敲质量或能力抵御爆炸..爆轰;有时也被称为敲门;作为燃料的燃烧空气的混合物;由于温度过高;在燃烧室内的压力条件的最后一个部分失控爆炸的定义..由于爆炸产生的压力波冲击;因此产生敲缸声;燃料燃烧和空气的混合物的扩张;导致丧失权力;局部温度过高;如果足够严重;引擎损害..有两种常用的汽油辛烷值测定的的方法马达法和研究方法..两者都使用的实验室相同的类型单缸发动机来做实验;这是一个头部和一个变量来表示敲缸爆震强度装置..作为燃料使用;发动机压缩比和空气燃料混合料试验样品进行了调整;试验出爆震强度..两个主要标准参考燃料;正庚烷和异辛烷;任意分配0和10辛烷值;然后分别是混合产生测试样品相同的爆震强度..因此百分比异辛烷的混合被认为是测试样品辛烷值;因此;如果相应的参考配方是由15％正庚烷和85％异辛烷;测试样品的额定电机向上或85研究法辛烷值;依据测试的一种方法..2.6.2完全燃烧汽油;是在理想条件下汽油在混合气中完全燃烧汽油所需要空气和汽油是15比1..这意味着1公斤汽油混合15公斤空气..汽油完全燃烧所需的空气被称为化学正确的混合物.. 15:1的比例适用于汽油;其他燃料有不同的比率.为了表示更实际;空气燃料混合物提供给空气燃料比14.7:1气缸偏离理论上完全燃烧所需;多余的空气因子R已被选定引擎：=空气质量提供/理论要求R为1 空气质量提供相应数额的理论的必要..<“1 空气或缺乏丰富的混合物..增加电力的射程R = 0.85 0.95输出结果..> 1.3 该混合物是如此精简的点火更长发生..精益失火超限.. = 0.95 0.85 火花点火发动机开发在5％ 15％空气不足的最大功率.. = 1.1 1.2 发生在最大的燃油经济性高达20％左右的过剩空气..为R≈1.0 这种过剩空气系数允许与化学计量比空转..= 0.85 0.75 良好的转换发生15％ 25％的空气不足..转型是指从一个给定的负载范围在实践中;过剩空气因素的R = 0.9 1.1已被证明是最实用的..在一定的操作条件下;燃料需求不同的混合模式于基本注入燃料的数量大于干预必需的. 冷启动在冷启动时;空气燃料混合物的发动机制定的加浓了..这是由于在起动速度低如果混合物燃油与空气粒子流动速度;并以最小的燃油蒸发和汽缸壁和进气口;在低温下润湿燃料..为了弥补这些现象;从而促进ID的冷发动机;注入更多的燃料才更容易起动..1．后启动阶段在低温起动后;必须加浓的一段短时期的混合物;以补偿较浠混合气的形成和摄入量与燃料缸..此外;在高扭矩;为更好的油门响应更加丰富的混合物时;加速从闲置的结果..2．热机预热阶段遵循冷启动阶段..该发动机的燃料需要;因为凝结一些仍然在寒冷的汽缸壁的热身阶段额外的燃料..在低温时;混合物的形成是由于较浓的大型燃料液滴的加入;由于与拟定的发动机在空气中混合燃料效率下降..其结果是;在进气阀门和进气歧管;只有在较高温度下燃油蒸发浓缩.. 上述因素均随温度降低必要的加浓的混合物.3．加速度如果油门突然被打开;空气燃料混合物瞬间倾斜过;以及混合浓缩短期在部分负荷运行;实现最大的燃油经济性和排放值是观察的关键因素.. 5．全负荷该引擎提供了在满负荷最大功率;当空气燃料混合比;必须加以丰富;在部分负荷..这种丰富依赖于发动机转速和提供最大的在整个发动机转速范围内尽可能的扭矩..这也确保在满负荷运行最佳燃油经济性的数字..6．怠速除了发动机的效率;发动机怠速主要决定于闲置的燃料消耗;在发动机冷高摩阻力;必须通过提高空气燃油混合输入克服..为了实现平稳运行在空闲;空闲速度控制怠速提高..这也导致了更快速热身的发动机..闭环闲置速度控制功能可以防止怠速过高..该混合物的数量相对应维持在有关的负载如冷发动机;并增加摩擦怠速所需要的数量..它还允许一个没有长期闲置的调整不断废气排放值..闭环闲置速度控制还部分地弥补在发动机老化带来的变化;并确保稳定的发动机整个使用寿命空转..7．空载减速时切断燃油降低燃油消耗不仅是长下坡运行和制动过程中;而且在城市交通..由于没有燃料完全燃烧;减少废气排放..8．发动机限速当发动机转速达到预设;教统会抑制燃油喷射脉冲..9..的空气燃料混合物在高海拔适应在高海拔地区的空气密度低就必须更精简的空气燃料混合物..在高海拔地区;由于较低的空气密度;容积流量的空气流量传感器对应一个较低的空气质量流量测量..这个错误可以弥补纠正的燃料数量..过度富集是可以避免的;因此;过多的燃料消耗..正如图2 - 20所示;燃料系统有一个油箱;油管;燃油泵;燃油滤清器和化油器..这零部件商店汽油;并提供给需要的化油器..简而言之;油箱储存汽油..行携带的燃料从油箱的燃料化油器..移动汽油燃油泵从油箱的燃料;并通过线化油器..燃料过滤器除去杂质的汽油..然后;化油器发送燃料的空气和汽油的混合物 - 进入燃烧室..1..燃油泵大多数车今天使用一个机械式燃油泵..这种燃料泵出了汽油;并通过油管向化油器或喷射系统..在大多数汽车;泵安装在发动机缸体..有些汽车电动燃油泵有一个..该泵安装在皮卡与燃料和燃料轨;发送单元油箱..对机械燃油泵操作取决于对凸轮轴叶..作者：爱在旋转移动泵摇臂..泵内;可以灵活的隔膜通过膜片弹簧摇臂;拉杆和链接..如图所示;燃油泵也有一个入口和燃料出口..由于凸轮轴上的旋转叶;横膈膜上下移动内部的引擎..隔膜的吸向下运动从进入泵油箱..隔膜向上运动推到了化油器;从泵的燃料..2..化油器化油器提供燃料比例的空气量流经喉管..当你在加速器踏板时;扩大开放节流阀吸引更多的空气通过化油器..化油器提供这取决于许多因素更丰富或更精简的混合物：发动机转速;负荷;温度;节气门位置..为了满足复杂的要求;一化油器是一个非常复杂的设备与许多内部通道及零部件.1喉管汽车化油器的设计是由喉管..喉管简直是气道狭窄的部分..空气通过化油器的喉咙;因为它移动的速度通过这个狭窄通道的旅行..通过建立合资企业增加的空气速度在喷嘴打开一个低压区..推动在一个大气压下水库内燃料的化油器浮子室称为..燃料是强行通过一根管子到空气流..2浮子室浮子室是一个储存和供应燃料的化油器水库..由于发动机使用的燃料;它会自动浮子室补充..浮动室内乐作品在同一作为一个抽水马桶水箱控股的基本原则..阿浮有赖于在水库燃料的顶部..作为燃料使用时;浮球液位下降..当浮动滴;一针阀打开..开放式针形阀允许从燃料的燃料泵入化油器的浮子室流..当商会是满了;针形阀是向上推;并关闭燃油进口..3测量燃油浮子室之间的压差和造成的燃料流..然而;为了维持适当的空气燃料比;化油器必须仅提供适量的燃料..为此;主放电管有一个小孔称为喷射或主射流..这允许燃料进入气流..在大多数情况下;这个小口子浮子室是在主放油管的末端..在那里;它的体积小燃油流量限制..4需要冷启动安排切断阀通过一个手段扼杀供气提供了丰富的混合物约8:1;并提供了一个轻松的粒子蒸发足够的引擎..5慢速贯穿化油器的空气量过小的时候;发动机只运行缓慢产生非常小的扼流圈抑郁症..这意味着太少将提供燃料和发动机将停止..缓慢运行的系统已经在这个区域里存在着抑郁症的高当发动机空转的电源插座..调节螺钉控制系统运行缓慢;一个螺丝设置空转速度运行缓慢等使混合物是让发动机转速平稳.. 6油门机制机制的油门控制空气燃料混合物流动..油门有几个;包括油门轴和节流板的一部分..通过打开和关闭;节气门控制的空气进入发动机燃料混合物流动..在诸如开放更多的空气流动;少的板关闭的气流..这些变化也气流控制汽油流..增加气流意味着更大的压力下降;从而更多的燃料流..气流减少意味着减少压降和流量较少的燃料..该议案的节流轴转动油门板..油门轴电缆连接到油门;反过来;连接到车内的油门踏板..司机控制空气燃料混合物踏板流动..2.6.5 莫特郎尼克点火和燃油喷射系统化油器将准确的空气燃料混合气发送到发动机..然而;并非所有的汽车都有化油器..许多现代汽车是用燃油喷射系统图2 - 22..燃油喷射系统与化油器式有许多优势..例如;它们能提供更多的精确控制..它们能够更好地匹配空燃比在不断变化的发动机状态..它们还提供更好的经济性和排放控制..此外;燃油喷射系统不需要化油器多余的那部分..该系统是一个莫特郎尼克发动机管理系统;包括控制单元ECU;它执行至少两个基本功能点火和喷油;但可能包含其他子系统需要改进的发动机控制1..测量值的检测气缸内的燃烧过程不仅受混合气和空气燃料比的影响;而且还受点火提前点火和点火火花的能源影响..一个优化的引擎控制;因此必须控制在整个喷射时刻的空气燃料比R A即喷入的燃油量;以及点火提前角α和持续角B..影响燃烧过程中的主要参数检测为测量值和一起处理瞬间发动机运行工况点火和喷射的最佳时机的计算..2..工作变量/传感器发动机转速和负荷是主要的工作变量..由于特定的点火提前角和精确的喷射时间对应于每个发动机的转速/负载地图点;重要的是所有的变量;其中涉及到同一个点都在相同的速度/负载面积计算..这不仅是可能的;如果点火提前和喷射时间以同样的速度和负载值发动机转速检测只有一次使用相同的传感器计算..这就避免了统计误差;可导致不同的负载传感器设备公差;例如;..而一个略有杆负荷范围不同的分配限制敲到发动机爆震的易感性增加..清除点火时间角和注射时间分配是由莫特郎尼克系统提供动力;即使在发动机运行条件下;3..莫特郎尼克系统该莫特郎尼克系统包括一系列子系统;两个基本子系统点火和喷油..综合后的系统更加灵活;可实现比相应的各个系统的功能更多..莫特郎尼克系统的重要特点是其作为一个最子功能所需的大量可自由编程实现地图..废气再循环EGR的功能至今尚未在欧洲使用;因此提供一种替代系统的唯一..控制系统的lambda只能算是今天;如果配合使用为减少尾统开环控制功能以及一个扩展的系统与闭环功能结合敲和lambda控制在管理系统气。

1.These parts can be grouped into four major categories; body, engine, chassis and electrical system.2.The internal combustion engine is most common; this obtains its power by burning a liquid fuel inside the engine cylinder.3.The chassis includes the power train, steering, suspension, and braking systems.4. A power train can include a clutch for manual transmission or a torque converter for automatic transmission, a transmission, a drive shaft, final driveand differential gears and driving axles.5.Basic types are: leaf springs, coil springs and torsion bars.6. A basic ignition system consists of the battery, low-lension cables, the ignition coil, distributor, coil high-tension cable, spark plug cables and sparkplugs.7.The operating strokes are: induction stroke, compression stroke, power stroke, exhaust stroke.8.The major parts of engine are engine block, engine heads, pistons, connecting rods, crankshaft and valves.9.These systems are the fuel system, intake system, ignition system, cooling system, lubrication system and exhaust system.10.The dry clutch mechanism includes three basic parts: driving member, driven member and operating members.11.The spur gears are mounted on four shafts: primary shaft (input shaft), layshaft (countershaft), mainshaft, and reverse idler shaft.12.The three types of braking systems are in use today: service braking system, parking braking system and additional retarding-braking system.13.It has five basic parts: the receiver, expansion valve, evaporator, compressor, and condenser.14.The three normally adjustable angles are caster, camber, and toe.段落一．Elements of the Power TrainThe elements of the power train must meet the following requirements;1)enable driving away,2)convert torque and speed,3)enable different directions of rotation for driving forward and backward,4)transmit tractive and pushing forces,5)permit different rotational speeds of the drive wheels when cornering,6)guarantee optimum operation of the engine (or electric motor ) in terms of fuel consumption and exhaust emissions.Standstill, driving-away and power interruption are made possible by operation the clutch .During driving away, the clutch slips and bridges the difference in rotational speed between engine and power train. When different operating conditions call for a shift of gear, the clutch separates the power train during shifting.Engine torque and engine speed are converted in the transmission in accordance with the tractive-power demand of the vehicle. The transmission design is influenced by the position of the engine and driven axle. Overall conversion takes place usually in a manually shifted transmission with variable transmission ratios and in a final drive with a constant transmission ratio. Nowadays, positive-locking transmissions with toothed gears as the most important elements are of even greater significance than non-positive friction-type transmissions.Two types of toothed-gear transmission are predominant: spur-gear transmissions of the countershaft type as manually shifted transmissions, and planetary-gear transmissions as power-shift transmissions. In addition, transmissions permit the different directions of rotation required for driving forward and backward.Final drive turns the drive through 90°and reduces the speed of the drive by a set amount to the vehicle.The differential provides for the equalization of the different axle and wheel speeds when cornering and for uniform distribution of the drive torque.二.The Hydrodynamic Coupling1. Hydrodynamic CouplingConventionally, the hydrodynamic coupling, also known as the Fötttinger coupling, has an impeller and a turbine wheel with vanes that usually extend in the radial direction. The impeller is often expanded to form a housing which surrounds the turbine. Since, due to the absence of an inner ring, there is no possibility of diverting the oil flow, the turbine torque is equal to the pump torque;公式Therefore 公式The index number depends on the design, the vane angle and the degree of filling of the coupling. The main working area of an hydrodynamic coupling is at v=0.9.2. Hydrodynamic ConverterThe hydrodynamic converter, also known as the Trilok or Fötttinger converter, is capable of operating in two phases: with torque increase in the first phase, and as a hydrodynamic coupling in the second phase. The usual design has three impellers:1) The pump, which is connected to the engine, acts like a centrifugal pump to produce the flow energy of a fluid.2) The turbine, which is connected to the transmission input, converts the flow energy back into mechanical energy.3) The reactor between turbine and pump diverts the flow of the fluid.Thus, the torque output is higher than the pump torque input from the engine. The torque increaseμμ=Mt/Mp is all the higher, the greater the speed difference (slip）between the pump and turbine. Withυ=0, i.e. with the turbine braked to a standstill (stall point, drive-away point), torque conversion reaches its maximum value and falls virtually linearly with rising turbine speed to a torque ratio of 1:1 at the coupling point. Above the coupling point, the reactor, which is supported on the housing by a one-way clutch, runs, torque-free, in the flow. Thus, the converter is now a clutch without torque conversion.For automobiles, the vane geometries are such that, at the drive-away point, the maximum torque increase μA is between 2 and 2.5. The hydraulic efficiencyηhydr=υμis similar in the conversion range to the speed ratioμand reaches values around 97% at high speed.Fluid couplings form the input element of automatic transmissions (in conjunction with planetary-gear trains, clutches, brakes and one-way clutches) and also of manually shifted transmissions in the form converter and clutch unit.三．Constant-mesh TransmissionFig.3-6 illustrates the flow of torque through a typical constant-mesh transmission. This type uses helical or double helical gears which are always in mesh. The mainshaft gear wheels are mounted on bearings and when a gear is required the mainshaft gear is locked to the shaft by a dog clutch.Although the mechanical efficiency is lower the helical gears are quieter and any damage resulting from a bad gear change occurs to the dog teeth instead of the actual gear teeth.元素的力量训练动力传动的要素必须符合下列要求;1)使开车逃走,2)把转矩和速度,3)使不同方向的旋转带动向前和向后,四)推进传送叶轮力量,5)允许不同转速时的驱动轮转弯时,六)保证了优化运行的引擎(或电机)从油耗和尾气排放。

汽车特性参数汽车尺寸可以使你了解它的外观，包括轴距、前后轮距、全长、全宽、全高、前悬、后悬、接近角、离去角、内长、内宽、内高、离地距、整备质量、总质量、车门数、乘坐空间和后备箱空间。

汽车的性能是否优良取决于其发动机和底盘。

而发动机是否给力取决于它的类型、排量、压缩比、最大输出功率和扭矩。

更重要的是先进的行驶系、制动方式、传动系统和车轮组成坚固耐用的底盘。

发动机性能参数包括发动机类型，缸径和冲程，排量、压缩比、气门组、功率、扭矩和点火方式。

气缸的直径称作缸径。

排量和压缩比是发动机两个常用的参数，排量表明了发动机的大小，压缩比是汽缸总容积与燃烧室容积之比。

功率指的是正常工作时的速度。

有效功率是指在正常条件下在发动机后部测得的实际功率。

指示功率是理论功率，指的是在理想状态下由发动机获得的最大输出功率。

指示功率是由发动机大小、排量、转速和气缸内压力的基础上通过理论计算得到的。

摩擦功率指的是用来克服在发动机和传动系内的内部摩擦。

摩擦功率来源于轴承、活塞在气缸内滑动、压缩冲程、发电机、风扇、水泵、皮带、空调、变速器、后差速器总成等。

汽车驱动轮上获得的功率称为行驶功率。

扭矩是一种确定工况的方法，指的是扭转力。

扭转力产生于发动机的燃料燃烧。

燃烧将活塞向下推。

而活塞带动曲轴转动，产生扭矩。

而扭转力引起车轮的转动。

底盘的性能参数包括悬架类型，制动器的类型和大小，转向方式和转弯半径，车轮的型号与大小，油箱容积。

发动机工作原理大多数发动机都是内燃机，如图示为往复式四冲程汽油发动机。

但是其他类型的发动机也有使用，比如柴油发动机，转缸式发动机（汪克尔发动机），二冲程发动机和层状充气式发动机。

往复式的意思就是“从上到下”或“从后到前”。

在往复式发动机中动力产生于活塞的上下运动。

几乎所有这种类型的发动机都依赖于一个气缸体。

气缸是由铁或铝铸造出来的，在缸体内有气缸和水套，冷却水在水套内循环。

汽缸盖覆盖在缸体顶部，形成了燃烧室。

缸体底部被油底壳所包覆。

第4章转向与悬架系统** 转向系统转向系统的设计目的是让驾驶员以最小的力将前轮向左或向右摆动，并且不能让转向盘有过大的运动量。

虽然驾驶员能轻松地使车轮摆动，但是道路的冲击却不被传递给驾驶员。

** 转向系统的基本组成基本的转向系统（见图4-1）可分为三个主要总成：·转向节转向臂总成；·连接转向臂和转向器的转向传动机构；·转向盘、转向轴和转向器总成。

图4-1 转向系统基本组成** 转向系统的类型转向系统可分为两种类型：人力转向系统与动力转向系统。

在人力转向系统中，驾驶员完成转动转向盘、转向器和车轮的全部工作。

而在动力转向系统中，利用液压动力辅助转向或电动动力辅助转向，来减小转动转向盘所需要操纵力。

目前使用的转向器有三种类型：循环球式转向器、蜗杆滚轮是转向器和齿轮齿条是转向器。

** 动力转向系统齿轮齿条式液压动力转向系统。

该系统的组成包括：机械式齿轮齿条转向器、液压工作缸和活塞、旋转滑阀、油泵、限压阀和储液罐（见图4-2）。

图4-2一种带有旋转滑阀的齿轮齿条式液压动力转向系统电控液压动力转向系统——Servotronic。

Servotronic是一种液压助力会随着行车速度而变化的的电子控制齿轮齿条动力转向系统。

在低速时，可获得最大助力。

随着车速的增加液压助力减小。

因此，Servotronic是一种速敏式动力转向系统。

Servotronic的组成部件有：车速表、ECU、齿轮传统式液压转向器、储液罐、电控液压变换器和油泵（见图4-3）。

图4-3 Servotronic——一种电控液压动力转向系统电动转向——Servoletric。

使用Servoletric电动转向系统（见图4-4），转向助力由电子控制的电动机所产生。

只有在需要时，才接通电动机。

通过一根带有力矩传感器的扭杆来测量驾驶员所加的转向力矩，另外还通过车速传感器来测量车速。

这两个信号被送往ECU。

ECU利用程序图计算所需的转向力矩和力的传递方向，然后给电动机发送相关输出信号。

第6章汽车电气与电子系统** 铅酸蓄电池与电路保护装置** 铅酸蓄电池铅酸蓄电池（见图6-1）是一种产生电压和输出电流的电化学装置。

蓄电池是今天的汽车所用的主要电能来源。

当充电时，蓄电池将电能转变成化学能。

当放电时，它将化学能转变成电能，从而产生电流。

图6-1 蓄电池的构造** 电路保护装置必须对电路进行保护，以防电路短路（意外触地）而导致线路烧毁。

还要对电气设备进行保护以防过载。

在电路中，电路保护装置必须与所要保护的电气设备或线路串联连接。

常见的电路保护装置有熔断器、易熔线和电路断电器，见表6-1。

所有的汽车熔断器通常都装在一个被称为熔断器盒或继电器盒（见图6-2和图6-3）的支架上。

一条电路可以用一个用作熔断器的特种导线来保护。

这根线被称为易熔线。

电路断电器通过双金属片和一组触点来电路的其他部分供电。

当电流超过断电器额定电流值时，双金属片就会发热并弯曲，从而将触点断开。

一旦冷却下来，电路断电器会将电路重新闭合。

继电器用来传导一个能使一只开关过热而损坏的大电流。

继电器是一些能使电路触点闭合的电磁开关。

大多数继电器通常都装在继电器盒或接线盒（J/B）内。

表6-1 丰田汽车电路图所用的电路保护装置Illustration 图Symbol 符号Name 名称Abbraviation缩写Fuse熔断器FuseMedium current fuseM-Fuse中电流熔断器High current fuseH-Fuse大电流熔断器Fusible linkFL易熔线Circuit breakerCB电路断电器Array图6-2 熔断器盒、继电器盒和接线盒在乘用车上的位置图6-3 一辆厢式车的熔断器盒、继电器盒和接线盒的位置** 充电系统充电系统利用发动机的转动来发电，以便给蓄电池充电和提供操作各种汽车电气系统所需的电能。

现代汽车充电系统的组成包括发电机和电压调节器（见图6-4和图6-5）。

图6-4 典型的交流发电机图6-5 一台典型的交流发电机（带电压调节器）零件分解图** 起动系统现代内燃机都利用电起动机来起动。