ABS (Anti-lock Brake System) – Anti-lock brake system ( active safety system of a vehicle ) . The system is designed to prevent the wheels from locking when sudden braking , which can lead to uncontrolled skid. The system allows you to keep stability and not to lose control of the car . ABS work can feel the vibration on the brake pedal during heavy braking , while you can not let go of the pedal , and the need , on the contrary , it is stronger push .
ABS consists of the following main components:
Speed sensors or acceleration ( deceleration ) mounted on the wheel hubs of the vehicle.
Control valves, which are elements of the modulator pressure to the line established by the primary braking system.
A control unit receiving signals from the sensors and controlling operation of the valves .
After the start of braking anti-lock brakes (ABS) and begins a permanent sufficiently accurate determination of rotational speed of each wheel . In the event that a wheel begins to rotate essentially slower than the other (which means that the wheel is locked close to ) the brake pipe valve to limit the braking force on that wheel. Once the wheel starts to spin faster than the other , the braking force is restored.
This process is repeated several times (or several tens of times ) per second , and generally leads to noticeable pulsation of the brake pedal . Usually , it is on this basis , the driver can determine when switching the antilock braking system (ABS).
Braking force can be limited as the entire brake system at the same time (single-channel ABS ) and brake system board ( two-channel ABS) or even individual wheel ( multi-channel ABS). Channel systems provide quite effective slowing , but only if the conditions of the clutch all the wheels more or less the same . Multichannel systems are more expensive and more complicated single channel , but have a greater efficacy in nonuniform coatings on braking if, for example , during braking , one or more wheels are put on ice and the wet stretch of road or curb.
In modern ABS is self-diagnostic system that controls the operation of all components of the system according to their physical parameters. Self-diagnostic system ABS fault lights a lamp on the instrument panel and writes the corresponding fault code in the memory of the control unit . After determining the component failure is excluded from the system or the whole system stops working and the brake system continues to operate .
Modern cars are gradually gaining ground electric brakes , operating independently on each wheel . In this case, ABS exists mainly as one of the control block algorithms such braking system , and has no effect on the pedal or the brake lever .
Effectiveness of ABS
In most cases, the presence of ABS can achieve significantly shorter braking distance than in its absence , besides ABS allows the driver to maintain control of the vehicle during emergency braking , that is may be possible to commit enough violent maneuvers directly during braking . The combination of these two factors makes ABS very significant advantage in securing the active vehicle safety.
An experienced driver can effectively inhibit and without the use of brakes, wheels controlling point of failure on their own ( most often this technique is used by motorcyclists braking ) , and weakening the braking force on the verge of locking . The effectiveness of such inhibition can be comparable with the inhibition using single-channel ABS. Multichannel systems in any case have the advantage that they can control the braking force on each individual wheel, which gives not only an effective deceleration but also the stability of behavior of the vehicle under difficult conditions uneven traction with the road surface .
For an inexperienced driver availability ABS better anyway, because it allows emergency brake in an intuitive way , simply by applying maximum force to the brake pedal or handle , and still be able to maneuver.
Under certain conditions, the ABS may increase braking distance. On loose surfaces such as deep snow , sand or gravel, locked under braking the wheels begin to dig into the surface, which provides an additional slowdown unlocked wheel brake slower in these conditions . In order to be able to brake effectively in such circumstances often do you want to disable the ABS . In addition, some types of ABS braking have a special algorithm for the loose surface , which leads to numerous latches wheels. This technique allows for effective braking deceleration without losing manageability , as at full lock . Surface type can be set manually by the driver , or may be determined automatically by the system by analyzing the behavior of a vehicle , or by means of special sensors determining the pavement .