Anti-lock braking system (ABS)
The hydraulic circuit anti-lock system (ABS)
In general, it makes no sense in this manual describe the operation of ABS, but you better get into your system, if you know how it works.
Typically, vehicles with ABS have disc brakes on the rear wheels. Also things and models Primera, t. E. Only vehicles with 2.0 liter engine can be standard or optional equipped with system ABS.
The decisive factor security system ABS - is the ability to prevent the wheels from locking under heavy braking, whereby the car remains manageable. Also, when emergency braking is a chance to go round an obstacle. But do not believe that the ABS system is capable of performing miracles. If it exceeds the physical limitations of the system, ie. E. The speed is too high, even cars with ABS can get into an accident.
Four wheel speed sensors that are installed in the steering knuckle and the rear hub holders, monitor independently the number of revolutions of each wheel. The illustrations mounting position of the sensor speed of the front wheels and the mounting position of the sensor speed of the rear wheels is shown, where the sensors front and rear wheels. The microprocessor receives signals RPM and detects abnormality regarding inherent parameters. Through this process, the braking pressure in the corresponding wheel seconds decreases or increases from 4 to 10 times, much faster than with a so-called pulsed braking the brake pedal further adjustment at each wheel is performed individually and not on all the wheels simultaneously as occurs when the brake pedal on vehicles without ABS. The rear brake circuit has two load-sensitive brake pressure control valve, which prevents further risk of blocking the wheels, especially if the car is loaded slightly.
Installation position of speed sensor front wheels
| || 1 - a bolt, 11 - 16 N ??? m |
2 - the gauge
Installation position of speed sensor rear wheels
| || 1 - a bolt, 4 - 6 N ??? m |
2 - a bolt, 11 - 16 N ??? m
3 - Sensor
Two hydraulic valve accurately allocate the required brake pressure on the front wheels, depending on traction. Two other control valves control the rear brakes. In this case, the electronic control system responds to the first slope to the blocking wheel. At the optimum braking the car remains manageable, supported by exchange rate stability and the car can be kept under control. At a speed below 15 km / h, the system is not working. The illustration shows a schematic representation of the system, through which you can navigate elements in the arrangement.
Something should be said about the hydraulic pump and pulse damper (7) and (8). The pump delivers the liquid to the pulsation damper and reduces the pressure in the brake caliper. The pump has an eccentric. When the pump piston via an eccentric press towards the liquid supplied from the surge tank to the damper, thus opening the intake and exhaust ports and valves connected thereto. The piston at the other side remains in its position, ie. E. The inlet and outlet valves on this side remains closed. Thus valves control the filling and emptying of the system. Pulsation damper accumulates brake fluid under high pressure and allows it to slowly return to the master cylinder.
So the ABS system provides you with additional security.
It is not recommended to perform any work on the system by yourself. The workshop will do it better. However, the car has always performed work, which affect the ABS, for example, pumping the brakes. Therefore, all work on the brake system should follow these instructions:
Thoroughly clean all connections and the area around them, before they ease.
Previous parts lay on a clean surface and cover with foil or a clean paper. Do not use cloth nappies.
Open cover the elements of the system, or plugging, if the repairs will be made immediately. This applies particularly to work outdoors.
Use only perfectly clean parts. In no case do not use parts that have been stored for a long time.
It is tempting to use the air compressor that plugs into the cigarette lighter socket, to clean parts. In no case do not do this if opened connection system.
After ignition hydraulic pump for 60 seconds, the system creates the working pressure. ABS warning lamp illuminates for 2 - 20 seconds, depending on whether the system pressure. The electronic control unit checks the individual components. If the detected any faults, the system operates as a conventional brake system without ABS. If this happens, t. E. The control lamp remains lit, contact a workshop. In the studio with the help of special equipment can diagnose problems that may have an electric or hydraulic nature.