Why brake-by-wire comes to your car

When a Formula One driver hits the brakes, he does not apply real pressure on the master cylinder controlling the rear brakes. Instead, it sends a signal to the computer to interpret, and that is the computer that determines the pressure to be applied to the rear brake calipers.

We call this technology brake-to-wire because it cuts the physical link between the pedal and the braking system itself. (Throttle-by-wire and steer-by-wire are also available). The sensors and actuators read the amount of pressure applied by the driver, and this force is transmitted to all master cylinder brakes using hydraulic fluid.

Formula 1 has been using technology since 2014 for rear brakes (fronts are still conventional). Luxury car manufacturers have experimented with. Soon, the brake-to-wire could make its way to your car.

The wire is better

For several years now, Toyota has been using brakes on hybrid vehicles (and some non-hybrid vehicles) of its Lexus brand. The new player is Alfa Romeo, who enters the game with his Giulia and Stelvio.

The Alfa unit was developed by Continental, best known for its tires. It's a control module that runs more systems than just your basic brake actuation. It replaces the original brake booster and it works just as well with electronic stability control as with ABS. These systems are traditionally managed by separate modules, which increases the complexity and weight in a car.

Wire braking systems also stop earlier, not just because the computer is faster than you. Alfa uses a mbadive brake booster that increases pressure faster than a conventional brake booster. This big brake booster uses it because it must not only provide pressure to the master cylinder, but also to the brake pedal itself to try to reproduce the feel of the pedal. A conventional braking system can go from a zero braking force to a full lock in 300 milliseconds, while Alfa's IBS can accomplish the feat in 100 milliseconds thanks to the brake booster. This results in shorter stopping distances in emergency braking.

Another huge advantage is the ability to customize the feel of the pedal. Many cars now come with performance modes that automatically change suspension settings at the touch of a button. Brake-by-wire can do this to stop the current. In Race Mode, the Giulia Quadrifoglio has a much steeper pedal feel.

And automakers have another reason to adopt wire braking. Alfa spokesman, Alexanian Berj, explains, "The main reason for choosing a cable braking system is that the Giorgio platform [which the Giulia and Stelvio are built on] was developed from the ground up. a blank sheet, the architecture must therefore be ready for additional motorizations. Reading the lines here tells us to think electric because hybrids and fully electric vehicles use regenerative braking. This means that when you release the throttle, the car uses the vehicle's momentum as mechanical energy to roll back the electric motor, which generates electricity to recharge the batteries while slowing down.

Alfa, like many other manufacturers, will want to use an electrically controlled braking system to couple with the regenerative brakes. A mechanical system in the middle of all electronics makes it possible to control as much as possible the slowing down of the vehicle through the combined use of regenerative braking and standard friction brakes. More control over the brakes means maximum regeneration of power and smoother stopping.

In your way?

The introduction of a wire brake on a performance car like that of Alfa is important because these vehicles are a test bench to see how enthusiasts react to electrical systems replacing mechanical counterparts. The direction offered by the Infiniti Q50 has long been criticized for giving the impression that the steering resembled a video game wheel, while the general reception of the Integrated Brake System (IBS) d & rsquo; Alfa was only positive.

Simulating the Brake Feeling is a distinct challenge. Driving a car with a fully hydraulic braking system, for example, you can physically feel the pedal becomes softer as it heats or overheats the brakes. If all you press is a wire that sends a signal to a control unit, then this physical sensation related to the overheating of the brakes is gone. It's up to the computer to do something about it.

In the case of Quadrifoglio, a warning light on the dashboard tells you to calm down before getting into trouble. Berj says that this braking sensation is the only thing that Alfa has tweaked since the initial release of the Giulia, and this has been done by the software update.

The resistance and fear of drivers have been the main stumbling block to the shift of by-wire technologies in mainstream cars. But they arrive. Look at aviation, where an electronic interface called "fly-by-wire" has endured the protests of traditionalists and eventually replaced most manual flight controls.

The brakes are still the most vital safety element of a car, so rely on an electrical signal to make them work n instillil not necessarily the confidence of buyers. Fortunately, there are traditional hydraulic backup systems for all cable braking systems available today. If the electrical system has become out of whack, you should never end up traveling 70 km / h on the highway without brakes in a car equipped with a cable brake.