 printable version
Anti-lock brakes (ABS)
Sedation is most effective when the grip of the tire with the road surface is greatest. During braking, tire slips on the surface, and the circumferential speed of the wheel becomes smaller than the vehicle speed.
| Fig. 6.3. The system ABS / TCS braking system of the vehicle Mazda 6: 1 - vehicles with left-hand drive; 2 - vehicles with right-hand drive; 3 - wheel speed sensor anti-lock brake system (front); 4 - rotor sensor anti-lock brake system (front); 5 - wheel speed sensor anti-lock brake system (rear); 6 - rotor sensor anti-lock brake system (rear); 7 - Switch System TCS; 8 - a combination of devices; 9 - warning light anti-lock brakes; 10 - a control lamp of TCS; 11 - a control lamp off TCS system
|
Anti-lock brake system (Fig. 6.3) limits the pressure generated in the hydraulic brake actuator, so that the amount of slip was optimal. The action of this system must be separate for each wheel. The system should respond immediately to each change of the surface (coefficient of friction), and the load on the car.
| Fig. 6.4. The scheme of system ABS / TCS braking system of the vehicle Mazda 6: 1 - the switch IG; 2 - SUS 15 and (fuse); 3 - anti-lock brakes and 60 (fuse); 4 - a combination of devices; 5 - warning light anti-lock brakes; 6 - alarm lamp brake system; 7 - indicator lamp off of TCS; 8 - a control lamp TCS (only system TCS); 9 - driver CAN; 10 - braking signal; 11 - actuator system of automatic speed control; 12 - the switch of TCS (only system TCS); 13 - Diagnostic connector the DLC-2; 14 - CAN-H; 15 - CAN-L; 16 - the wheel speed sensor anti-lock brakes; 17 - the storage battery; 18 - switch braking signal; 19 - unit, switch to cleaner and a washer of glasses, car navigation unit, a control unit
|
Anti-lock braking system prevents the wheels from locking under heavy braking, thereby reducing the braking distance. The adhesive force between the wheels and the road in this case more if braking continues to rotate the wheel. Even at full braking the car remains manageable. Speed sensors, one for each wheel measured by the wheel speed. The sensor signals (see. Fig. 6.4), the electronic control unit calculates the average speed approximately corresponding to the vehicle speed. Comparing the speed of each individual wheel with an average speed calculation, the electronic unit detects the status of the individual wheel slippage and thus sets. a wheel is stored in predblokirovochnom condition. When one of the four wheel speed sensor transmits a signal for blocking the wheel, the electronic control unit immediately produces a signal corresponding to the closing of the inlet solenoid valve, which shuts off the brake fluid through the conduit to the brake wheel. This brake force is constant. If the slide continues, the exhaust valve opens and the pressure in the hydraulic system of the brake is reduced. The wheel does not slow down, the excess brake fluid back into the tank. Once again, the wheel begins to rotate, the inlet valve opens and the exhaust - closed. Circuit pressure increases again, and the wheel brakes. Changing cycles of braking and free-wheel speed is very fast (several times per second) and continues until the vehicle is stopped or until the brake pedal is released. The process is repeated when braking for each wheel as long as the brake pedal is released. Emergency shutdown system provides ABS with any failure or low voltage in the vehicle electrical system (below 10). ABS fault does not affect the operation of the brakes. The hydraulic drive consists of a hydraulic unit, brake calipers and brake pipes. The hydraulic unit includes an electric pump that creates pressure and the solenoid valves.
| 
