What Is Antilock Braking System Or ABS In Cars?

How ABS works and what it is for

Developed to ensure greater safety when landing aircraft, ABS was the first electronic safety system integrated into the car and the basis on which systems such as traction control or stability control were later developed. The antilock braking system, which is what these three letters mean, is one of the active safety elements of the car that has prevented the most accidents. Its main mission is that we can maintain control over the trajectory of the vehicle while applying the maximum brake pressure. How does ABS work and what is it for? Well, it serves so that we can brake and change trajectory at the same time, preventing the wheels from locking, and it does it as we tell you below.

The main purpose of a vehicle's brake system is to reduce the speed at which it is traveling and thus to stop the wheels from spinning. However, due to inertia, it is possible that our car continues in motion even if the wheels are completely stopped. This has a very important drawback and that is that if the wheels do not turn, but the car continues to move, it does so without control over the path we want to take. If we block the front wheels during braking, we will not have control over the direction. No matter how much we turn the steering wheel to one side or the other, we will not be able to go where we want (avoid the pedestrian that surprises us, the car that skips the crossing, etc.). The vehicle will follow the path that the inertia marks it at that moment. You can continue straight, turn towards the side where the asphalt is in better condition, towards the inside of the cant of the curve, etc. ... Running out of direction is one of the biggest nightmares that can surprise us while driving. To avoid this inconvenience and thus increase the active safety of cars, different anti-blocking systems began to be developed to ensure that we could direct the trajectory of our car ourselves. In the 60s they were merely mechanical, from the end of the 70s and throughout the 80s electronic systems were developed, so that from the 90s on, most cars were installed as standard. Fortunately, nowadays all registered cars must install it and fewer and fewer vehicles roll on our roads without ABS.

How ABS works

Well, the idea is very simple. When we step on the brake pedal, what we do is push a liquid. Since these are not compressed, we transmit that pressure to the wheel brakes. If the wheels lock up, just lift your foot off the brake a little to get them spinning again. We already have the principle of operation: remove pressure from the liquid that we compress with the pedal, even if the driver does not lift his foot. To do this, taps are inserted in the brake circuit (solenoid valves) which, upon receiving an electrical signal from the ABS control unit, open the passage of fluid to a channel other than the wheel, so that the brake of that wheel is freed.

We have named two elements of ABS: The control unit, which is the brain of the system, and the solenoid valves, which are the ones that, by opening and closing, tighten or loosen the brake pressure on each wheel. The control unit has to know when to open or close the valves and, to make that decision, it needs sensors to tell it whether or not the wheels are turning. We already have all the components of the ABS system, which are:

Unity of command.

• Solenoid valves (they are usually mounted in a compact unit called a hydraulic group).
• Rotation sensors on the wheels.

How does ABS make decisions?

At all times the control unit receives information on the turning speed of each of the wheels. At the moment in which the speed of one of them is lower than that of the others, this means that it is blocked or about to do so, which causes the control unit to give the order to remove pressure from the brake of that wheel to match its turning speed with that of the others.

What does the driver notice when braking with ABS?

In normal conditions, we do not notice anything at all, only when the solenoid valves have to work do we feel a vibration in the brake pedal that is caused by the return of the liquid when the corresponding solenoid valve releases pressure.

How should I brake with ABS?

Well, exactly the same as in a car without ABS. The only difference is in the case of extreme or emergency braking. In a car without ABS, we must press the pedal fully, release the pedal a little to turn the steering wheel and avoid the obstacle and step again once the dodge is overcome. In a car with ABS, we simply have to fully depress the brake and clutch and let the system work throughout the braking. A car with ABS will allow us to avoid the obstacle while braking with all our might (always within the limits of physics, of course). We must step on the clutch pedal to prevent the engine from stalling. With it off, we will not be able to return to our lane after a dodge, nor will the power steering work.