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What is the ABS system and how to use it?

What is the ABS system and how to use it?

The abbreviation ABS stands for “anti-block system”. It is designed to ensure that the braking of the vehicle occurs without total blockage of the wheels. Thanks to this, the car remains stable on the road surface and reduces the brake footprint. In case of emergency braking, the vehicle does not lose maneuverability and controllability.

Before we deal with the very concept and principle of anti-blocking, we learn the history of the ABS creation.

Historical information

The prerequisites for creating an anti-blocking design are associated with the problems of blocking wheels on railway vehicles.

The fact is that with total stopping of the wheels of the train, production appears on the rim which reduces ride quality composition. In addition, total blocking of the wheels can cause a derailment of the railway transport. The problem was solved by introducing into the design of the locomotive a cargo auto-mode. This device automatically carries out adjustment of braking, taking into account the load carriages. The brake mode is implemented by changing the air pressure in the brake cylinders.

The most approximate version of modern anti-blocking structures is the production of ABS developed by Avions Voisin in the 20s of the 20th century. Anti-blocking was used in the implementation of braking aircraft on the runways.

With regard to land vehicles, then in those years used cable brakes. Such brakes required physical effort from the driver, and blocking the wheels adversely affected maneuverability during braking. Creation of hydraulic systems of a stop of transport also has not solved the given problem.

Initial attempts to develop anti-lock systems for cars were undertaken by Bosch in 1936. Unfortunately, they were unsuccessful, because at that time digital electronics was not in sight. There was simply no technology for instantly responding to wheel locking.
With the development of semiconductor technologies in the 1960s, the situation in this regard has somewhat improved. But the initial ABS samples, which arose in the 70s and were introduced into the automotive industry of General Motors, proved unsafe due to the jamming of the driving wheels.

The original safety locking system was built in 1978 on a Mercedes-Benz C class. In the internal structure, the anti-lock had an electric controller, speed sensors on each wheel and hydraulic valves that were located on the brake circuit. With the rotation of the wheels at different speeds, the system regulated the braking force and brought the rotation speed back to normal. Then the ABS again increased the braking force.

Modern anti-lock models deliver and reset the braking force up to twenty times per second, allowing the driver to maneuver in cases of emergency braking. In the current automotive industry, the anti-lock system is installed in 75% of all vehicles in the world.

How the ABS is constructed?

Anti-blocking contains the next structure components:

  • Sensors on each wheel that measure the speed of movement. They fix the speed of the wheel and transmit electrical signals to the control unit.
  • The control unit. Having received an electric signal from the sensor, the unit sets the braking mode by means of the intake and exhaust valves.
  • Hydraulic valve. Thanks to them, the brake fluid is put into the pressure accumulator.

How ABS works?

All phases of the auto-lock operation can be represented as follows:

  • The pressure rises.
  • The pressure is held back.
  • The pressure is reset.

Anti-block system analyzes the speed parameters of each of the wheels using sensor electrical signals. When there is a probability of blocking the wheels, the control element closes the intake and exhaust valves. In this connection, the pressure parameters in the brake circuit remain unchanged even when the brake pedal is subsequently depressed.

If the wheel locking continues, the control element opens the exhaust valve, and the intake valve remains closed. The brake fluid is discharged into the pressure accumulator. The wheel speed parameters are increased, and the brake circuit is depressurized. If the battery capacity is insufficient, the back feed pump is used. In this case, you can feel the pulse of the brake lever.

When the wheel rpm rises, the anti-block control element covers the outlet and opens the intake valve. In the circuit of the brake system, the pressure increases.

All stages of the anti-block operation are continued cyclically until the vehicle stops completely or stops blocking the wheels. At the same time, the anti-block system does not turn off.

Advantages of the anti-block system

Advantages of anti-blocking can be assessed with sudden braking in an emergency. When braking in standard situations, the difference is difficult to perceive. Among the advantages of the system can be identified:

  • Preservation of maneuverability in emergency braking. Since the wheels and moving parts are not blocked, the driver can drive the vehicle.
  • The length of the brake path is reduced. On a flat and dry road, the vehicle will not slide. The process of braking in this case is uniform and smooth.
  • The car does not record when making a turn with braking. Anti-lock wheels minimizes such situations even on slippery surfaces.
  • It is recommended for installation for drivers with little driving experience. Only experienced drivers in the slip situation can propel the gas pedal, and then again add speed to the maneuver.
  • Increases the efficiency of braking the vehicle. The smart system smoothly stops the car. Although under standard conditions, you will not feel the difference between normal braking and using an anti-lock system.
  • Availability. Anti-lock wheels can be installed on almost any vehicle that has a brake system in the design.

But like any electronic system, ABS has disadvantages.

Disadvantages of the ABS

All the disadvantages of anti-locking appear on the loose surface of the road and small speed. The negative sides of ABS are:

  • Increases the length of the braking distance when braking on an uneven surface. The system starts to brake on each bulge, and when in contact with the road, the braking force is not optimal. Therefore, in such situations, it is necessary to maintain distance and reduce speed.
  • The road surface has various coupling properties. For example, asphalt with areas of snow or ice crust. In such situations, the system does not have time to select the optimal braking mode.
  • Low speed of transport. Before stopping the transport, the system turns off. Therefore, if you roll on an inclined surface, it is not recommended to brake to the stop.
  • Increases the length of the braking distance on loose surfaces. In the system of braking on the sand or gravel surface of the road, you just need to completely block the rotation of the wheels.
  • The maintenance of the car becomes more complicated. With the installation of ABS, the tasks of varying complexity in mounting the brake system become more difficult. Even the usual change of brake shoes requires professional skills.
  • Clogging of speed sensors. In this regard, you need to monitor the status of the device and promptly clean the electronics from dirt and dust.
  • Psychological factor. Hoping for electronics, many drivers lose their vigilance on the roads.

Despite its disadvantages, most European cars have an anti-lock system in their equipment. For example, BMW, Mercedes and SAAB do not already manufacture vehicles without anti-blocking. In the top class of cars (Lincoln, Cadillac, Mercedes class C, BMW 7 series), the installation of the system is a requirement, without any exceptions. In a large class (Mercedes I, BMW 5 Series, Ford Scorpio, Ford Taurus), now it is rare to find specimens on which an anti-block is placed for additional financial means. Most companies (GM, Volvo, Audi) offer only the cheapest models without anti-blocking system. In the middle class (Audi 80, BMW 3 Series, Ford Mondeo, Volkswagen Passat) a vehicle in which there is no ABS, even for additional money, are considered to be uncompetitive.

Many drivers believe that ABS is a waste of money. In addition, in some situations, it not only does not save from accidents, but it can provoke them. We have already talked about the descent from the mountain, when the system turns off. Without knowing about it, you can easily incur trouble for yourself. But on the other hand, inexperienced drivers can feel more confident and do not use the old antiquated method of braking. In addition, in emergency situations, we can not control traffic during normal braking.
To use the anti-blocking system or not is individual case. Before categorically refusing the use of ABS, it is worthwhile to weigh the pros and cons. And remember, no intelligent system can improve grip on the road. Even having installed an anti-block system, you need to be alert and attentive on the roads.

Date: 05.10.18     Views: 98