Electronic Wedge Brake

[m3_lover]

Saw this.. hope you guys might like it


http://www.autoweek.com/apps/pbcs.dll/a ... 06011/1065

[tomislavp4]

Well if they need only half the distance of ordinary brakes it´s amazing piece of tech

[Ted68]

Yes, I am the guy who can't get Firefox to work in my computer, so maybe I'm just not too into the electronic age, but here are my concerns with this system....

I drive as my everyday transport a 1998 GMC Half-ton truck. A low-tech gas hog that is as reliable as a hammer. Around the 130,000-mile mark the air conditioner quit working. I rolled the windows down and took it to the mechanic. Diagnosis? A faulty electrical connector replaced for $60.00 and all was well again.

Now, if I had driven a car for 130,000 miles with electronic brakes and had a connector fail, rolling the windows down will not appreciable slow the vehicle. No brakes is no brakes. You don't stop, you hit things or people. The article states that Mercedes Benz withdrew it's high tech braking system for reliability issues.

Maybe I'm too old, but I like simple mechanical connections between the driver and the vehicle for steering, throttle and brake control. All this "...by wire" stuff is interesting as for technology and vehicle dynamics, but if I'm driving I want control.

[Tom]

I've had 2 brake failures driving in the back garden with conventional brakes. The first time in my Metro the brakes were always half on so eventually one day I got brake fade and had to slalom to slow down. The AX burst a seal and I used the handbrake.

Seems unlucky, I'm not even on the road yet and its happened twice already, but it goes to show the current system that most cars use is unreliable too, and normal folk on the road would just panic when the brakes failed, they wouldn't use the handbrake because they don't know its merchanical and would probably put the clutch in. (the wrong thing to do, drop it in a high gear and the engine will slow the car down)

So no matter what systems and backup systems you have as soon as one fails its up to the driver to stay calm, that's what will make the difference.

[Giancarlo]

Last time I checked - tires stop the car. Boasting that this new EWB can shorten stopping distance by 1/2 reeks of the stench of marketing departments.

Unless SIEMENS has been able to alter the laws of physics with their new brakes - no way is it going to stop a car any quicker. If the clamping force is increased all you get are locked tires or the ABS system engaging in the same manner that a conventional brake system would.

Remember folks: anything can look good on paper!

On a side note: what about brake feel? A computer cannot duplicate what the reactions of a human yet. For a better example: stand on one foot. You'll notice that you have many muscles twitching and relaxing yet you are not really thinking about it. The same thing goes on when you modulate the brakes (at least with me). Can a computer do that? Not yet...

[Ted68]

Seems unlucky, I'm not even on the road yet and its happened twice already, but it goes to show the current system that most cars use is unreliable too,

Sure you haven't upset somebody?

[G-Rock]

I think what they mean by "half the stopping distance" is a misprint. What they should have written was, "application time is cut in half"
The problem with most braking systems is that they lack high speed grab. Most cars that do, tend to be too grabby at low speeds so it's always a comprimise.
High speed grab is what you need to avoid a collision. It can mean the difference between a collision and an escape. Every tenth of a second can save valuable distance.
With this system i can see the cars computer being able to regulate the brakes speed and power of actuation depending on the driving situation.
At high speeds be very aggressive and at low speeds, less grabby.
Another possiblity would be a more precise ABS system. Anyone who races knows how flexible brake hoses can expand and reduce brake sensitivity. This system could eliminate that and shorten brake distances by making the ABS work more on the limit of adhesion.

[ginsu]

It's true that the grip of the tires are fundamental in your stopping distances. I've done some brake testing with R-Compound tires, they are incredibly poised under hard braking, in fact, it's very hard to lock them up unless you throw the car into a corner while braking.

I'd be much more impressed if tire companies could make a long lasting R-Compound tire...too bad the FIA doesn't give a damn if consumers ever see any of the technology developed...after all, there must've been some pretty interesting compounds made by Michelin last year when there were no tire changes.

[RH1300S]

I think G-Rock has it in a nutshell. I admit that the idea of electronic brakes makes me nervous and also I doubt the feel would be good (at the moment )

I have had practical experience of the difference reducing the bite time makes to stopping distances:

One of my cars I always ran performance pads (Mintex & Tarox) - once I came up with the wizard ruse of fitting Ferodo competition pads. In short the braking distances were hugely shorter (and more consistent) - this stopping improvement was mainly down to the way the brakes got more bite a lot earlier from the point I pushed the pedal; then after that I could sustain hard braking more precisely as he car slowed down.

Yes, the car was still tyre limited and the tyres were the same - but I was using the stopping power a lot earlier in the braking phase.

Ohh.....downside of running race Ferodos was that the disc and pad wear rate was an almost perfect match - it got very expensive and also coated the side of the car with brake dust and metal particles from the discs

[f1.redbaron]

More info:

http://www.siemensvdo.com/products_solu ... nology.htm


Video:

http://www.vdodayton.com/sycomax/uis/me ... 93_EWB.mpg

[mep]

Clever idear.
Watch the video and you will understand how it works.
You need a kind of activating energy to start the braking
After that you don't need more force tho brace because the rotation of the wheel brings the needed force.

[tomislavp4]

I´m into this hi-tech stuff, I mean we have to make same progress right
Even the most simple part can happen not to work sometimes. I´m sure that they´ll test the hell out of it before leting it hit the market.