What are ABS Brakes and how do they work?

Driving at speed, within the realm of the law of course, is something we all enjoy but it does come with risks. Those of us who drive sensibly understand this and take steps to mitigate potential dangers, but we can only do so much. Our senses are limited and there’s only so many dangers we can anticipate. Naturally any help we can receive is always appreciated and fortunately in modern vehicles, help is at hand.

One danger that’s frequently present when we drive in the rain is a wet and slippery road surface. This makes driving at speed so much riskier; our brake distance is dramatically increased and the likelihood skidding or spinning out of control becomes so much more prevalent. An anti-lock brake system (ABS) can help in this situation enabling the car to maintain stability and control.

What is an anti-lock brake system?

As the name suggests, an ABS is a safety system in cars (and other vehicles) that prevents the vehicles brakes from locking up and becoming ineffective. The danger is, if the brakes lock up, the driver can lose control of their car, unable to slow down or stop when the need to. Of course, this can be dangerous for the driver, other passengers and road users that happen to be nearby.

This technology helps keep the car on course, keeping the wheels in control of the steering wheel and therefore dictated by the driver. Essentially, the idea is to allow the driver to continue steering in the way they choose to and brake at the same time. Without such technology, the slippery road surface can overwhelm the tire traction, resulting in skidding regardless of what the steering wheel is doing. When locked in place, the wheels are unable to be moved without the drivers say so.

How does an anti-brake system work?

Many of us know what ABS technology is but we may not know exactly how it works. A detailed understanding of how it does what it does’ instead of just what it does’ can help a driver take advantage of it should they find themselves in a situation where they are relying upon it. While ABS technology is designed to work automatically, knowing how it works and trusting it can help the driver know not to steer frantically should they feel a momentary loss of control, as this could make matters worse. After all ABS technology works by making sure control is retained by the steering wheel and not governed by the slippery surface beneath.

If a tire/wheel is unable to grip the road surface, for example on ice, it is likely to keep spinning without moving the car forward. It’s unable to gain any traction resulting in no forward momentum or worse, could supply an overabundance of momentum that the driver may not want. ABS technology regulates the release of brake fluid and pressure being supplied to the brakes. This enables the wheels to lock and reset, allowing them to re-adjust to the road surface, applying the correct amount of pressure and spin appropriate for that particular surface. This in turn allows the car’s brakes to once again become effective, passing control back to the driver. This also allows for the driver to keep the wheels facing the direction they want instead of where the slippery surface causes them to slide.

ABS technology is commonly made up of 4 major parts, each working in conjunction with the rest. There are:

A Speed Sensor

This makes sure each wheel is turning at the speed it should and makes sure no individual wheel is spinning faster than the others. Meaning the driver need not worry about certain wheels acting independent of the rest.

An Electronic Control Unit

The ECU is responsible for adjusting wheel rotation and acceleration based on the signals it gets from the speed sensors, it also makes sure the brakes are working proportionally to what may be necessary.

A Hydraulic Control Unit

The HCU receives signals from the ECU to regulate when and how the brakes are applied and released. It does so by applying hydraulic pressure to either force or release brake power.

Various Valves

These are controlled by the ECU and HCU to release or apply each individual brake as dictated. These open and close to release pressure periodically, allowing the car to come to a controlled stop as directed by the driver.