1、第四章 Braking System（制动系统）1.Energy is required when a vehicle is accelerated from rest to a certain speed. A proportion of that energy is now stored in the vehicle and is called kinetic energy. In order to reduce the speed of the vehicle, the brakes have to convert the kinetic energy to heat energy; t
2、he speed of conversion governs the rate at which the vehicle slows down.汽车从原地起步加速到某一速度需要能量。储存在汽 车中的那部分能量称为动能。要降低车速 ,制动器必须 把汽车的动能转换为热能；转换的速度决定了汽车减 速的快慢。2.The three types of braking systems are in use today: service braking system, parking braking system and additional retarding-braking system. The se
3、rvice braking system and the parking braking system have separate control and transmission devices. The service braking system is normally foot-operated, while the parking braking system is hand-operated.目前使用的制动系统有三种类型：行车制动系，住车制动系 和辅助制动系行车制动系和住车制动系有独立的控制和传 动装置行车制动系通常使用脚刹，而驻车制动系通常使用 手刹3.Two types of
4、brakes are used in modern cars: drum brakes and disc brakes. Since 1976, all cars have used disc brakes on the front wheels. Most cars use drum brakes on the rear wheels . In both drum and disc brakes, a hydraulic system applies the brakes. The hydraulic system connects the brake pedal to the brake
5、parts at each wheel.目前使用的制动器有两种类型：鼓式制动器和盘式制动 器从 1976 年开始，所有的汽车前轮都使用盘式制动器, 大部分汽车后轮使用的是鼓式制动器. 在盘式制动器和 鼓式制动器中都使用液压系统. 液压系统把制动踏板与 每个车轮的制动部件相连接.4.These have two shoes, anchored to a stationary back-plate, which are internally expanded to contact the drum by hydraulic cylinders or a mechanical linkage.这种制
6、动器有两个固定在制动底板上的制动 蹄，通过液压轮缸或机械杆系作用从内侧向 外推开与制动鼓接触。5.In the case of the simplex brake, C*(brake factor) is the sum of the values for the individual shoes, and is 2.0（referred to a specific coefficient of friction)A disadvantage of this design is the great difference in the braking effect between the two
7、 brake shoes, and the resulting greatly increased wear on the leading shoe. For this reason, the trailing shoe is often equipped with a much thinner lining than the leading shoe.就领从蹄而言， C*表示各蹄的值的总数，且 . (特指某一摩擦系数） 这种设计的缺点是两个制动蹄 制动效果有很大不同，结果大大增加了领蹄上的摩 擦因此，从蹄的摩擦衬片比领蹄薄6.An advantage of this type of brak
8、e is the nearly equal brake lining wear on both shoes and the higher internal transmission ratio in comparison to simplex brakes.这种制动器的优点是两个蹄上制动衬片磨损几乎相 同，与领从蹄制动器相比它的内传动比较高7.Many cars have 2 L.S. front brakes and L. the intake air is compressed via automatic suction and delivery valves.空压机用做能源一般是活塞型的
9、通过自动进 气阀进入的空气在其内被压缩21.The combination brake cylinder consists of a single-chamber diaphragm cylinder for the service brakes and a spring-brake actuator for the parking brakes. The cylinder and spring brake actuator are in tandem and act on a common pressure rod.复合式制动室由行车制动器的单室膜片弹簧制动气室和驻车 制动器弹簧助力装置组成
10、制动气室和弹簧助力装置串联在 一起并对压力杆作用 22.Electrohydraulic braking systems are designed to allow electonic control of vehicle braking while retaining a reduced hydraulic system. The EHB control unit receives inputs from sensors connected to the brake pedal. In normal operation, a backup valve is closed and the co
11、ntroller activates the brakes of the wheel through an electric motor driven hydraulic pump. When the controller goes into a fail-safe mode, the backup valve is opened, which allows the brakes to be controlled through a conventional hydraulic circuit.电液制动系统允许电子控制汽车制动,同时保留了简化的液压系 统. 电液制动系统控制单元接受与制动踏板连
12、接的传感器的输入. 正常工作时, 后备阀关闭, 控制器通过由液压泵驱动的电动机控 制制动器. 当控制器进入失效安全模式时,后备阀打开, 并允许传 统的液压回路控制制动器.23.In order to brake the vehicle, the field coils are supplied with current (from the battery or alternator) and generate a magnetic field. Eddy currents are induced in the rotors as they pass through this field. Th
13、is generates a braking torque whose magnitude is a function of the excitation of the stator coils.为了刹车，用电池或发电机给励磁线圈供电从而产生磁 场当转子经过磁场时感应生成感应电涡流这样产生的 制动力矩的大小是定子线圈中励磁电流的函数24.he function of an anti-lock, or anti-skid, braking system is to prevent the wheels from locking under hard braking. Maximum brakin
14、g force is obtained just before the wheels lock and skid. Such anti-skid systems are useful on slippery surfaces, such as ice and snow, where the wheels may lock easily.防抱死制动系统的作用是防止在强制动条件下车轮抱死。只在车轮抱死拖滑时才会获得最大制动力。 这类防滑系统在冰、雪等光滑路面非常实用，因为 在这些路面上车轮容易抱死。25.The wheel-speed sensor monitors the motion of t
15、he wheel. If one wheel shows signs of locking, there is a sharp rise in peripheral wheel deceleration and in wheel slip. If these exceed defined critical values, the controller sends commands to the solenoid-valve unit to stop or reduce the buildup of wheel-brake pressure until the danger of lock-up
16、 has passed. The brake pressure must then be built up again in order to ensure that the wheel is not under-braked.轮速传感器监控着车轮的运动，如果一个车轮出现抱死信号， 也就是外车轮减速度急剧增大且车轮开始滑动如果超出临界 值，控制器给电磁阀发送命令来停止或降低制动压力，直到抱 死的危险消除然后制动力再增大确保车轮制动力不会不足26.A wheel-speed sensor consists of a toothed pulse ring and an inductive whee
17、l- speed pickup. The pulse ring is mounted on the hub and , as the rotates, produces in the wheel-speed pickup an A.C. voltage, the frequency of which is proportional to the wheel speed.轮速传感器由运动的齿圈和磁感应传感头构成齿圈安装在 轮毂上，车轮转动时，在传感头上产生频率与车速成正比的 交流电压27.From the signals from the wheel-speed pickups, these m
18、icrocomputers calculate the wheel speeds as well as the wheel decelerations and accelerations. A vehicle reference speed is formed from the wheel speeds of two diagonally opposite wheels. With this reference speed and the individual wheel speeds it is possible to calculate the brake slip for each wh
19、eel. If a wheel has a tendency to lock, this is determined from the wheel-acceleration and slip signals.通过来自传感头的信号，微机不仅计算出车速而且还计 算出减速度和加速度参考车速由两对角线位置车轮的 轮速构成用这个参考速度和单胎速度可以计算出每个 车轮的滑动率车轮是否有抱死趋势决定于车轮的加速 度和滑动信号28.A separate frame must be light yet strong enough to resist the various loads and road forc
20、es. Commercial vehicles normally use a separate steel frame to provide the rigidity needed to support the various loads. The two long side members of channel section are riveted to a number of cross members to give a low weight frame which offers great resistance to bending, twisting.分离式车架必须足够轻巧而且结实
21、，以承受变化的 载荷和路面作用力。商用车通常使用分离式钢质车 架，以获得较好的刚度来承受变化的载荷。两根槽 形的长纵梁铆接着很多横梁，这使车架重量较轻， 具有较好的抗弯和抗扭能力。 29.Most cars use a unitized body construction, a combined body and frame. Unitized body construction is lighter than body/frame construction, but noisier. Rubber mounts are used between the body section and me
22、chanical parts to absorb vibrations. The floor pan is made of sections that support the rear suspension and the transmission.多数轿车采用承载式车身，也就是车身和车架融为 一体。承载式车身比非承载式车身质量轻，但噪声 大。在车身和机械部件之间安装橡胶块以吸收振动 。地板由一些支撑后悬架和变速器的部件组成。30.Modern cars have a blend-air system that mixes warm and unwarmed air to heat the c
23、ar. The “heart of the system is the heater core . Hot engine coolant flows from the radiator, through the water pump hoses, and to the heater core. Therefore, the heater core is always hot. The temperature of air entering the passenger compartment is controlled by the amount of air moving through th
24、e heater core. This heated air is blended with fresh, cool air that bypasses the heater. Small doors in the heating system regulate the air-flow. Control levers on the dash panel open and close these doors to direct air to the heat ducts and window defrosters.多数汽车采用加热过的或未加热过的空气的混合起来加热汽车。 暖风系统的核心是热芯。
25、热的冷却水来自散热器，通过水泵软管 流到热芯。这样，热芯总是热的。流经热芯的空气数量控制着进 入车厢的空气温度。加热后的空气同流经加热器的新鲜冷空气混 合。加热系统中的一些小风门控制空气的流量。前围板上的控制 杆开启和关闭这些风门，从而将空气引入输热管和风窗除霜器。31.The purpose of venting systems is to draw in fresh air and remove stale air from the interior of the car. Fresh air venting systems direct air to two different plac
26、es. First, they can direct outside air into the heater housing. This air either can bypass the coil or it can be heated by the coil. Second, the air can move directly into the passenger compartment through small vent doors in the dash panel or at floor level. Venting also can take place by opening t
27、he windows.通风系统吸入新鲜的空气，排除车内不新鲜的空气。 通风系统将新鲜空气引入两个地方。首先，通风系统 将外部空气引入加热器壳里，空气从线圈旁流过或被 线圈加热。其次，空气可通过前围板或地板上的小风 门直接将空气引入车厢. 打开车窗也可实现通风。32.Levers and switch to regulate air and heat are located on the dash panel. Some heater controls use small vacuum motors for simpler, more positive action. Others use ca
28、bles, while some use a combination of the two. The vacuum to operate the motors comes from the engine intake manifold.控制空气和热量的杠杆和按钮安装在仪表板上一 些加热器的控制器使用真空电动机提供简单可靠的 工作另一些使用缆线，还有一些两者兼用驱动 电动机的真空来自发动机的进气管 33.As the compressor raises the pressure of the refrigerant, it also heats it. The hot refrigerant i
29、s then pumped into the condenser , where it cools by giving off heat to air passing over the condenser fins. As the refrigerant cools, it condenses into a liquid. Still under high pressure, the refrigerant passes into the receiver. The receiver acts as a storage tank to furnish refrigerant to the ex
30、pansion valve at all times. From the receiver, the high-pressure liquid refrigerant passes to the expansion valve.压缩机增加制冷剂的压力，对制冷剂进行加热。高温的制 冷剂被吸入冷凝器中，将热量释放给流经冷凝器散热片的 空气而得到冷却。制冷剂冷却时冷凝为液体。在高压作用 下，制冷剂进入储液器。储液器不断地给膨胀阀供应制冷 剂。高压液态的制冷剂从储液器流向膨胀阀。34.The expansion valve controls the flow of refrigerant into t
31、he evaporator, where a low pressure is maintained by the suction side of the compressor. As it enters the evaporator, the refrigerant begins to boil by absorbing the heat from the air passing over the evaporator core. Having given up its heat to boil the refrigerant, the air is cooled and passes int
32、o the passenger compartment. The refrigerant continues to boil in the evaporator until all the liquid has vaporized. From the evaporator, the refrigerant flows back to the compressor to repeat the cycle.膨胀阀控制着进入蒸发器的制冷剂流量，在蒸发器里压缩 机吸入端保持低压。制冷剂进入蒸发器时，吸收流经蒸发 器芯的空气的热量而沸腾。空气释放热量使制冷剂沸腾， 得到冷却后进入车厢。制冷剂在蒸发器里持
33、续沸腾直到液 体完全蒸发为止。制冷剂从蒸发器流回压缩机，重复吸热 制冷循环。1、Energy-supplying device 供能装置 2、Control device 控制装置 3、Transmission device 传能装置 4、Brake 制动器 Metering Valve 节压阀 Proportioning Valve 比例阀 Check Valve 单向阀 Solenoid Valve 电磁阀 Combination Valve 组合阀 Delay Valve 延迟阀 Modulator Valve 调节阀 1、Energy-supplying device 供能装置 2、C
34、ontrol device 控制装置 3、executive device 执行装置 1 Compressor 空气压缩机 2 brake cylinder 制动气室 3 brake valve制动阀 4 water-drain valve 放水阀 5 air reservoir 湿储气罐 6 master reservoir 主储气罐 7 pressure regulator 调压阀 8 barometer 气压表 9 bugle 喇叭 Drum brake 鼓式制动器 Brake-fluid 储液室 Vacuum booster 真空助力器 Brake pedal reservoir 制动
35、踏板 Master cylinder 制动主缸 Vacuum connection 真空管 Simplex drum brake (Leading trailing shoe brake ) 领从蹄式制动器 Duo-trailing shoe brake (Two trailing shoe brake) 双从蹄式制动器 Double leading shoe brake 单向双领蹄 Duo-duplex drum brake（ Dou two leading shoe brake ）双向双领蹄式制动器 Uni-servo drum brake单向自增力式制动器 Duo-servo drum brake 双向自增力式制动器 Simplex drum brake 领从蹄式制动器
