Here’s Why Your Next Car Might Replace Brake Lines And Fluid With Wires And Electricity

Over the past few decades, electrification has resulted in the virtual elimination of several once-key automotive liquids. Power steering fluid is the most obvious example across the board, but electric vehicles have also dispatched with engine oil, automatic transmission fluid, and of course, gasoline. However, innovators in the industry aren’t done yet. Two suppliers have already developed solutions for eliminating another common maintenance fluid: brake fluid.

While there are already cars available with brake-by-wire pedals that actuate the brake master cylinder electronically, Brembo’s Sensify and ZF’s EMB take things one step further and feature electrically actuated calipers rather than hydraulically actuated ones. In the case of the former, all four calipers can be specified to feature an electromechanical mechanism that clamps the pads to the discs, while in the case of the latter, all four calipers or only the rear calipers can be electromechanical, with the second setup controlling each hydraulic front caliper by way of a separate electronically actuated master cylinder. Contrast this with a traditional brake caliper setup in which all caliper pistons are acted upon hydraulically, and it’s clear we’re soon to be playing in a whole other realm.

So what benefits do electromechanical brakes have in the real world? Well, they promise faster actuation than hydraulic brake solenoids, which should lead to more precise control of each individual wheel. Automatic adjustments can be made at the calipers themselves for weight transfer and differences in surface friction, and threshold braking in seriously slippery conditions can be achieved by computer algorithms rather than by driver skill. Also, since the pedal is entirely electronic, there’s no heavy traditional pulsating anti-lock braking feedback that may scare drivers not used to getting into ABS during panic braking instances. In addition, electromechanical calipers promise to eliminate brake pad drag which should reduce particulate emissions, and they should integrate seamlessly with regenerative braking in electrified vehicles.

There are purported perks for automatic emergency braking, too. ZF claims that its electromechanical calipers can offer a 29.5 feet reduction in automatic emergency braking stopping distance from 62 mph over a standard hydraulic braking system. That could be the difference between changing your shorts and filing a claim, but without further details on how that number was reached, we’ll have to wait on third-party validation.

Oh, and there are some potential maintenance benefits to this evolution of brake-by-wire. Because electric calipers keep the pads clear of the discs in regular operation, it’s possible that pad changes could be a cinch. There might not be a need to retract the pistons if retraction is their default state to avoid dragging the pads on the discs. Also, removing the need for traditional brake lines eliminates the possibility of having, say, a rear brake line rot out after 20 years in the rust belt. It also means that brake fluid flushes on electromechanical calipers literally can’t be neglected (because there’s no brake fluid to flush).

Are there any potential downsides? Well, I could see a few. The first is unsprung weight, as adding a powerful electric motor and mechanism to a caliper is almost certainly a heavier proposition than a few ounces of flexible brake tubing and brake fluid. The second is packaging, because oh brother, these calipers look huge. Sure, they mean manufacturers won’t have to run brake lines, but the sheer depth of the calipers may require compromises in knuckle design and suspension arm placement to achieve sufficient steering angle. I also can’t help but wonder about rats. They don’t normally chew metal brake lines, but wiring? Happens all the time.

Still, so long as rodents don’t find themselves attracted to the cabling, electromechanical brake calipers offer up some interesting possibilities. With contracts already inked as per Automotive News, expect to see these systems appearing in production cars within the next few years.

Top graphic images: ZF

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