For some reason I remember when MB's were first with ABS brakes and the biggest worry was the pickup coming from behind................here we go again.


http://www.autoweek.com/apps/pbcs.dll/article?AID=/20061109/FREE/61106011/1065
Super Binders
Electronic wedge brakes will change the way we stop

By GREG KABLE

AutoWeek | Published 11/09/06, 8:37 am et


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Never heard of the EWB or electronic wedge brake? Don’t worry. Chances are you’ll be hearing a lot about it in coming years.

That’s the opinion of German electronics specialist Siemens, which claims the high-tech stoppers, currently being tested for use on upcoming models by Europe’s leading carmakers, will revolutionize the safety standards of future generations of road cars by dramatically shortening stopping distances compared with more traditional hydraulic braking systems.

Efforts to improve the efficiency of braking systems have led to some interesting innovations in recent years, including the use of ceramic carbon materials in brake discs and electronic activation of parking brakes. But those developments will seem minor compared to the leap Siemens is claiming for its new electronic wedge brake.

Not to be confused with the electrohydraulic Sensotronic brakes introduced by Mercedes-Benz in 2001 but subsequently removed from sale early this year due to unsolved reliability issues, the electronic wedge brake represents a bigger breakthrough. The idea behind the system is not exactly new, with similarities to the arrangement found on horse-drawn carriages from the 18th century, where a wedge was used to bring the wheel to a standstill. But rather than relying on a hardened piece of wood for a binder, the electronic wedge uses state-of-the-art electronics and an innovative wedge-shaped connection to provide the sort of stopping ability that existing hydraulic units cannot match.

Unlike today’s traditional hydraulic brake, which requires the buildup of forces before the caliper is able to grip the disc, the electronic wedge brake uses a series of interlocking triangular teeth that offset between the caliper and the disc. In all, it is claimed to require just one-tenth the energy used by hydraulic braking. A small electric motor pushes the pad toward the rotor by a lateral movement—much like how a watermelon seed can be ejected at high velocity by squishing it between your fingers. The entire system runs on the standard 12-volt electrical system found in most cars.

Really clever, however, is that the kinetic energy of the car automatically increases the braking performance. In theory, the faster you are traveling when the brakes are applied, the more powerful they become. When the pad is applied to the disc, the momentum of the rotating disc draws the pad farther up an interlocking series of wedges, applying greater braking pressure and increasing stopping efficiency.

A series of electric motors push in and pull out at an extremely high frequency, while a torque sensor controls the braking force and keeps the wheels from locking up, thus alleviating the need for a conventional antilock braking system. With each brake unit operating independently from the others, it also means the electronic stability control can be programmed to operate on a much finer calibration, without the typical pulsating effect evident in some cars today.

In tests, a prototype with the wedge brakes regularly required less than half the distance to come to a complete stop than the prototype with the standard brakes, a company official said.

As well as providing greatly improved braking ability, wedge brakes are significantly lighter than today’s most advanced hydraulic units. With fewer moving parts, they also could be more reliable and last longer.

When will we see the new brakes begin filtering through to the road? Sources say the first car with wedge brakes, an Audi, BMW, Mercedes-Benz or Porsche, is planned for launch in 2008.

Here's a page at Siemens VDO about this.

It includes a link to an animation showing the configuration and operation of some of the components.

Holy god. Half the stopping distance compared to hydraulic brakes? That means your average economy car will take 60 feet to stop from 60 mph.

__________________
1985 CA 300D Turbo , 213K mi

Better not brake-check a tailgator if you have wedgies.

B

I'm wondering if they will have hydraulics as backup, incase your battery dies.

Maybe you can pop in a couple of AA's and be on your way to the garage to get your charging system fixed.

Or better yet, have one of those handcrank chargers, that way, you can go on till your arm gets tired.



And the rich get richer - by being rear-ended, and suing.



(above comments mostly tongue in cheek, of course, with a smidge of sarcasm and dry humor - my fave)

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

This was part of the issue about ten years ago. Delphi was proposing electric brakes. There was concern of electrical failure and there is quite a bit of history wit hydraulic brakes. The DOT permitted the idea of an electric brake for the rear axle and hydraulic for the front....it never went anywhere.

The technology sounds great, however, it is more complicated and electrical.

How good it will be probably depends on the manufacturer. Just like anti-lock…some companies make good anti-lock systems that enhance the stopping and other make systems that just make driving a little more precarious.

Where I work we have electric brakes on our larger boat trailers.

Wonder if thats the future. Certainly looks interesting, shorting stopping distances are always a good thing.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200