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Investigation Brembo's Brake by Wire Tech

It is very interesting how seemingly unrelated news items or conversations can come together.

During the Detroit Auto Show, Brembo sent out a press release detailing a system that I found interesting. Brake by Wire. Having read about fly-by-wire in aviation and experiencing electronic throttle control in my car on a daily basis, the concept of a future brake by wire system intrigued me.


This is something that Brembo has been working on for quite some time. Originally they had started working on the concept back in 2000, but development ground to halt when some customers bailed on the project. It was the proliferation of hybrid technology that helped prompt Brembo to take another look at brake by wire technology in 2010/2011.

A brake by wire system is comprised of BCUs (Electro-Hydraulic Brake Control Units that either send hydraulic pressure to a caliper or are integrated with the caliper), a VCU (Vehicle Control Unit), an active pedal simulator in addition to provisions for hydraulic lines and electronic signals. Packaged together, this will allow for complete braking system that will eventually have no weight penalty when compared to conventional hydraulic systems, but offer greater functions and performance with consideration to cost.

But why brake by wire? Many reasons, just like there are many reasons for the above mentioned fly by and drive by wire systems. Chief amongst them is integration into the various systems already present in current automobiles, including hybrid powertrains. It is now normal for a car to have various drive modes, but braking has never been a part of those modes. It simply wasn’t possible. The advent of electronic controls in the gearbox, suspension and also power steering has allowed their features to be adjusted to match varied driving conditions.

The integration of brake by wire to the rest will allow braking to enter the modern era.

But this is not a new thing. According to Brembo Engineers, brake by wire technology was utilized by both Williams and McLaren back in the 1990-93 F1 seasons, but the use went away when active suspension was banned for the 1994 season.

In 2014, brake by wire returned to the F1 scene, but only on the rear wheels and only in limited simple functions. Because the brakes are used to generate the hybrid power and only limited power can be recovered in F-1, the braking function and feel changes whether the power regeneration is on or off.

That is where the brake by wire comes into play, it is programmed to mask the feeling and performance so that it doesn’t disturb or upset the driver that is on the edge. As far as a sports car application, a Brembo Engineer said, “LMP1 would be a prime place for this, as their regulations are much more open, although currently the front to rear balance must be kept fixed.”

But that is only a part of the application. One intriguing aspect is what Brembo calls Zero Drag Torque Calipers. The typical brake caliper causes frictional drag, as a pad is always in slight contact with the rotor. That contact produces wasteful drag, reducing the efficiency of that car. Attempts to reduce that drag has always been met with drivability issues – mainly concerning feel that doesn’t give the driver confidence in the brakes.

Because brake by wire is electronically controlled, that “feel” can be adjusted to suit requirements, meaning a brake by wire car could be indistinguishable by the average driver.

For performance applications, the sky is the limit. Just like electronic-controlled paddle shifting has actually become faster than the typical manual gearbox, brake by wire allows programming and integration of all sorts of performance applications from 4-wheel independent braking to supplementing and/or even replacing current traction and stability control.

While us driving enthusiasts don’t care much about autonomous driving, we can’t ignore it, it is coming and brake by wire lends itself perfectly to that application. It would also be an ideal application for people with limited mobility issues, as the brakes could be controlled by a joystick or similar apparatus.

Currently Brembo has strong customer interest in its product and seeing some small volume applications on the market within four years is their target. Just like ABS, which at first was only available on top level cars due to cost, brake by wire will likely face a similar future. Initially only available on exclusive makes but eventually trickling down to the masses.

Which brings us to what I’d originally thought was a totally unrelated topic, the Porsche PDK gearbox. A lengthy and thoroughly entertaining conversation at Daytona with the now retired Head of Porsche Motorsports, Hartmut Kristen, revealed that PDK when raced by Porsche in the 962 era “was ahead of its time by about 20 years.” That it “set up to produce it for our lines, but we couldn’t do it affordably at that time.”

Eventually they were able to do so and now through technology advances, the electronically controlled dual clutch gearbox has eclipsed the manual gearbox performance and efficiency wise and has trickled down to mainstream cars like the Ford Focus I have in my driveway.

It may take a while, but I know that eventually brake by wire technology will also trickle down, with the increased efficiencies and performance capabilities being available to the masses.

I just wonder what will be next…

Gary Horrocks