《汽车专业英语读译教程 教学课件 ppt 作者 宋进桂_ 18-U10TB》由会员分享，可在线阅读，更多相关《汽车专业英语读译教程 教学课件 ppt 作者 宋进桂_ 18-U10TB（21页珍藏版）》请在金锄头文库上搜索。
1、UNIT10 BRAKING SYSTEMS TEXT B Traction Control System (TRAC) and Electronic Stability Control (ESC),PROFESSIONAL ENGLISH,UNIT 3 BRAKING SYSTEMS TEXT B Traction Control System (TRAC) and Electronic Stability Control (ESC) Traction Control System (TRAC) Components TRAC Operation Intake Electronic Stab
2、ility Control (ESC) What Is Electronic Stability Control? How ESC Works Many Names,本次课学习内容,本次课学习目标,掌握 TRAC和ESC系统的有关属术语 掌握TRAC和ESC系统的组成和原理 提高翻译技巧与阅读能力,NEW WORDS,PHRASES AND EXPRESSIONS,Traction Control System (TRAC) and Electronic Stability Control (ESC) Traction Control System (TRAC) The purpose of
3、the traction control system (TCS, or TRAC) (Fig.10-3) is to prevent wheel spin from occurring due to acceleration. The maximum torque that can be transmitted to the wheels is determined by the coefficient of friction generated between the road and the tires. If torque exceeds that level, the wheels
4、are likely to spin. Conditions for TRAC operation may include: loose gravel, slippery road surfaces, acceleration while cornering and hard acceleration 1. Once activated, the TRAC System reduces engine torque and rear wheel speed as necessary to bring the vehicle under control. The ABS ECU, TRAC ECU
5、 and ECM all work together to provide traction control. ABS speed sensors are monitored by the TRAC ECU which in turn controls a sub-throttle plate and applies the rear brakes. The ECM also retards engine timing while the ABS modulates pressure at the rear brakes.,Fig. 10-3 TRAC system components,Co
6、mponents The TRAC OFF switch is located on the instrument panel above the center console. It allows the driver to activate or deactivate the TRAC system when the switch is depressed. The system defaults to ON when the ignition switch is cycled. The TRAC OFF indicator light goes on when anyone of the
7、 following occur: the TRAC system is deactivated by the TRAC OFF switch. a TRAC related problem is detected with the engine. an ABS related problem is detected. The TRAC indicator light indicates when: the system is operating. a malfunction occurs in the system (it remains illuminated to warn the dr
8、iver). the diagnostic mode is set within the TRAC ECU (the light blinks the trouble code).,Sub-Throttle Valve Motor The sub-throttle actuator uses a step motor located between the main throttle valve and air cleaner. It is fitted on the throttle body and controls the position of the sub-throttle val
9、ve based on commands made by the TRAC ECU thus controlling the engine output. By controlling the sub-throttle plate, engine management controls engine torque reducing wheel spin. Sub-Throttle Position Sensor This sensor is fitted to the sub-throttle valve shaft. It converts the sub-throttle valve op
10、ening angle to a voltage signal and sends this signal to the TRAC ECU via the ECM (Engine ECU). The sensor operates in the same way as the main throttle position sensor. TRAC Pump The function of the TRAC Pump is to generate brake fluid pressure necessary for applying the rear disc brakes when the T
11、RAC system is operating. It draws brake fluid from the master cylinder reservoir, pressurizes and directs it to the TRAC brake actuator.,Fig.10-4 Sub-throttle valve motor,TRAC Brake Actuator The TRAC brake actuator consists of two cut solenoid valves and three spring loaded valves which regulate the
12、 brake fluid pressure in the right and left rear wheels. The rear wheels are controlled independently through the ABS actuator based on signals from the ABS ECU. The master cylinder cut solenoid valve opens and closes the hydraulic circuit from the master cylinder or TRAC pump to the ABS actuator. W
13、hen the TRAC system is operating, it supplies the brake fluid pressure from the TRAC pump to the disc brake cylinders via the ABS actuator. It also prevents the fluid from flowing out of the ABS actuator pump to the master cylinder. The reservoir cut solenoid valve is located between the return side
14、 of the ABS 3-position solenoid and the master cylinder. It returns the fluid from the disc brake cylinders back to the master cylinder reservoir. The pressure regulator valve controls the brake fluid pressure generated by the TRAC pump.,The relief valve relieves the systems highest pressure should
15、a malfunction occur 2. The check valve prevents fluid from flowing out of the disc brake cylinder to the TRAC pump. TRAC Operation During normal operation (TRAC not activated) all solenoid valves of the TRAC brake actuator remain inactive when the brakes are applied. As the brake pedal is depressed,
16、 brake fluid pressure generated by the master cylinder is applied to the disc brake cylinders, via the master cylinder cut solenoid valve, and the 3-position solenoid valves in the ABS actuator. When the brake pedal is released, fluid pressure returns from the disc brake cylinders to the master cylinder. During vehicle acceleration (TRAC operative) when a rear wheel slips the TRAC system controls the engine output and braking of the rear wheels to help prevent whe
