1、Unit Five Automobile Braking System Passage BBasic Brake Parts and Safety Brake System Typical braking system has the following basic parts:brake pedal,brake booster,master cylinder,brake lines and brake fluidas shown in Fig.5-8 Brake pedal Brake pedal located on the right foot side in the car can a
2、mplify the force of your leg and evenly transmit it to the brake fluid when the right foot steps on the pedal(see Fig.5-9).Brake booster Brake booster mounted on the firewall between the brake pedal and master cylinder increases the force applied to the pistons in the master cylinder so that the car
3、 can stop with less effort The two most common types of power brake boosters are vacuum booster and hydraulic booster,both of which accomplish the same thing Master cylinder A master cylinder has actually two completely independent working chambers respectively with one piston,each controlling two w
4、heels If only the two of the wheels lose their brakes,the other two wheels will still be able to stop the car On the top of the master cylinder is a brake fluid reservoir that is transparent so as to see the fluid level without opening the cover(see Fig.5-10).Brake lines The brake lines run from the
5、 master cylinder along the frame of the car to each wheel(see Fig.5-8).The lines are made of steel and reinforced rubber hoses which are flexible enough to use only at the front wheels and rear axles where the suspension system works and wheels turn when you steer Brake fluid Brake fluid travels fro
6、m the master cylinder to the wheels through the brake lines It is special oil that has specific properties It must withstand cold temperature in winter without thickening as well as very high temperature in summer without boiling Safety brake system One cannot think of the safety brake system withou
7、t thinking of ABS,nor of ABS without EBD,EBA and ESC,etc ABS,short for Anti-lock Brake System,is designed to prevent the car from skidding on a wet and slippery road,and make the car shorten brake distance and stop in a straight line without loss of the directional control without loss of the direct
8、ional control ABS consists of ECU(Electronic Control Unit),4 wheel speed sensors and APV(Anti-lock Pressure Valve)as shown in Fig.5-11 ECU continuously monitors the rotating speed of each wheel through the 4 wheel speed sensors When one or more wheels are going to lock up,the ECU immediately command
9、s the APV to ease the brake pressure on the affected wheels ABS“pumps”brakes up to 15 times per second,much faster and more effective than a human driver can EBD,short for Electronic Brake-force Distribution,as the subsystem of ABS,is designed to automatically modulate the brake force on the front w
10、heels and the rear wheels according to the load of the car,the condition of the road and the adhesion between the tire sand road surface in order to get more balanced and closer to the ideal brake force distribution EBA,short for Emergency Brake Assist,is designed to keep the electronic eye on how y
11、ou are braking,and if you suddenly get into an emergency and have to stop your car shortly,EBA automatically boosts the brake force to help you in order to save you in an emergency ESC,short for Electronic Stability Control,is designed to keep the car from rolling over in a panic swerve when running
12、 on a wet and slippery road It uses some sensors such as wheel speed sensors,steering wheel position sensors and yaw sensors to determine whether the car goes the right direction you want If the car is not going in the direction you want,ESC can apply the brakes on individual wheels to bring the car
13、 back under controlNew Words and Expressions amplify mplifai vt 放大,扩大 transparent trnsprnt adj 透明的 frame freim n 车架 fluid level液面,液位 reinforced riinfst adj 加强的 thickening ikni n 增稠 boiling bili n 起沫 skidding skidi n 侧滑滑行,漂移 slippery slipri adj 滑的 command kmnd vt 命令,指挥 ease iz vt 减轻,缓和 affected fekti
14、d adj 受到影响的New Words and Expressions pump pmp vt 点制动 modulate mdjuleit vt 调节,调整 adhesion dhin n 附着力 tire tai n 轮胎、车胎 swerve swv vi 突然转向,突然转弯 individual individul adj 个别的 directional control 方向控制 in a panic 惊慌地 steering wheel 转向盘Common Automobile Terms firewall faiw:l n 发动机舱壁 brake booster制动助力器 maste
15、r cylinder制动主缸,制动缸 braking line/brake line制动管路 anti-lock brake system(ABS)防抱死制动系统 electronic control unit(ECU)电控单元 anti-lock pressure valve(APV)防抱死液压阀 emergency brake assist(EBA)紧急制动辅助系统 electronic brake distribution(EBD)电子制动力分配系统Common Automobile Terms electronic stability control(ESC)电子稳定控制系统 wheelspeed sensor车轮转速传感器 steering wheelposition sensor转向盘位置传感器 yaw sensor横摆传感器
