C8 ME To Have “Brake By Wire” System

[John]

Will one of the ways the mid engine Corvette save weight would be to have a brake by wire system?

[Quote=gmauthority]ZF Highlights Brake By Wire System In Silverado, Sierra

• BY SEAN SZYMKOWSKI
• — OCT 23, 2018

As high-efficiency engines fail to produce enough vacuum pressure to generate the ideal amount of stopping power, German supplier ZF has introduced its answer. The 2019 Chevrolet Silverado and 2019 GMC Sierra are some of the first vehicles to benefit.

It’s called Integrated Brake Control (IBC) and it replaces the vacuum booster and associated cables, sensors, switches, electronic controllers and vacuum pumps. According to a Wards Auto report last Thursday, the system works with a pedal simulator. Fluid in the master cylinder is displaced to an accumulator and the system measures pedal travel. A motor with a ball screw then pushes a plunger to deliver hydraulic fluid to the wheels.

According to ZF, the motor can do all of this and generate brake pressure measuring 1 g in just 150 milliseconds. Automatic emergency braking is also quicker with IBC; the system can deploy full stopping force in a quarter of the time compared to a traditional braking setup.

Another benefit of the system is the ability to incorporate the electronic stability control in the one module. Thus, the 2019 Silverado and 2019 Sierra feature one package for the braking and stability control system. It also saves 11 pounds over traditional components.


ZF added it has contracts in place to provide the IBC system to eight vehicle platforms between multiple companies by 2020. Several more automakers plan to tap ZF for the technology, and there’s a very good chance we’ll see IBC also make its way to the next-generation Chevrolet Tahoe, Suburban, GMC Yukon and Cadillac Escalade. The SUVs will share the new full-size pickups’ T1 platform.[/Quote[

Read more: http://gmauthority.com/blog/2018/10/...#ixzz5UmiV1IWR

[Frenzy36]

OK Sounds great , just wondering how it would act if the pedal simulator were to become inoperative? Total Loss of Braking? At least with the hydraulic systems and a vacuum booster there is still braking even if a leak develops on one of the fluid lines. However if it proves to be safer somehow - Bravo.

[John]

Would be nice for the ME not have the weight, cost and complexity of running hydraulic brake lines to the opposite end of the car.

[meyerweb]

OK Sounds great , just wondering how it would act if the pedal simulator were to become inoperative? Total Loss of Braking? At least with the hydraulic systems and a vacuum booster there is still braking even if a leak develops on one of the fluid lines. However if it proves to be safer somehow - Bravo.

Good point. There are cars on the road that have BBW systems, but as far as I know they have a redundant purely hydraulic system in place as a failsafe, so they don't save any weight. There are plenty of electric / electronic only control systems on cars, and other items, that we don't demand a mechanical backup for, but generally not critical safety systems. For example, our windows don't have a mechanical crank backup, but our door locks do.

Oh, and I'm sure this BBW system still has dual master cylinders to that you don't lose all braking in the event of a leak to one wheel. In the U.S., that's a federal mandate.

[Shadow]

This could be an interesting development, especially as it is not in the patent stage, but already in production Chevy trucks. However, like always, the devil is in the details.

One thing is for sure, is that we are, as typical, lacking in the key details. But maybe a promising enhancement?

[John]

A poster named “Rruuff” further learned that the brake-by-wire system, at least on a Chevy pick up, results in an 11 pound weight reduction. That is very nice!

[meyerweb]

Thinking about this a little more, almost all late model cars on the road have drive-by-wire throttles, including our C7s (and probably C6s, too). I haven't read of any failures of those on the forums, or heard anecdotally about any issues with other cars. We may be at the point where these systems are more than reliable enough.

Aside from that, I'm not sure this prevents manual braking if the system fails. ZF's web page says "replace[s] the electronic stability control, vacuum booster, and vacuum pump (where needed), as well as associated cables, sensors, switches and controllers... Fluid in the master cylinder is displaced to an accumulator and the system measures pedal travel.." It sounds like it's replacing the vacuum booster with an electric booster. So I think there is still a physical connection between the brake pedal and the hydraulic system, and the electronics are measuring how far you pushed the pedal by measuring how much fluid is displaced.

Were I designing this, I would do it so that if the electronics fail a valve opens, routing the hydraulic fluid pushed by the brake pedal directly to the brake lines going to the wheels. Losing the electronics would be the same as losing power brakes on car with a vacuum booster. The pedal is real hard to push, but you still have brakes. (I've experienced this on old cars with power brakes that didn't have a vacuum accumulator: if the engine stalled, the power assist went away.)

[JB]

I believe my alfa stelvio ti sport has brake by wire. In my opinion its seamless

[John]

Thank you. I remain excited by its being, in the 2019 Chevy PU’s, 11 pounds less. Maybe this is part of GM’s lightweighting program. Hope we see tens more example of this program in become ME reality. What we all would not give for the ME to weight 100+ pounds less than a comparable C7.

If you have not yet watched this 2:15 video, it is the most exciting video I have watched this past year! It shows one component being computer re-designed to save 40% mass and simultanteously reduce the part count from eight parts to just one.

https://video.marketing.gm.com/10508...-weighting.mp4

[meyerweb]

Wow, zombie thread. (The last post before today was in October of 2018). Welcome to the forum, annykidsman.

FWIW, Harlan Charles (C8 program manager) has completely debunked the rumor that the C8 has brake by wire. It is e-boost (electric boost instead of hydraulic), not brake by wire. So there's no vacuum pump to replace.