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.
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.
Anti-blocking contains the next structure components:
All phases of the auto-lock operation can be represented as follows:
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 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:
But like any electronic system, ABS has disadvantages.
All the disadvantages of anti-locking appear on the loose surface of the road and small speed. The negative sides of ABS are:
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