Siemens "Electronic Wedge Brake"

http://i14.tinypic.com/2uh4744.jpg

http://www.autoweek.com/apps/pbcs.dll/article?AID=/20061109/FREE/61106011/1065


Super Binders
Electronic wedge brakes will change the way we stop

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.

interesting, wish there were more diagrams to see how it works. :)

interesting, wish there were more diagrams to see how it works. :)

more info:

http://www.siemensvdo.com/products_solutions/chassis-carbody/body_chassis_electronics/braking-technology/braking-technology.htm

NYCshopper,

I learn much more about automobile technology here than I do anywhere else because of you :)

Anyway, this EWB technology is exciting!

I dont see any discussion about wear and longevity...

I dont see any discussion about wear and longevity...

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.


Otherwise it's very interesting - wonder what this will do to the new car market in 2008 and to various racing series. If it does work as advertised, I wonder if it would be possible to retrofit the system.

I see it, I've read it, but I don't "get it" exactly.

<# johnny 5> Need more input </# johnny 5"

But it sounds really cool!

what happens to Brake feel--or rather the lack thereof. If there's no hydraulic system behind it, where's the feedback come from?

what happens to Brake feel--or rather the lack thereof. If there's no hydraulic system behind it, where's the feedback come from?

I wondered the same thing. I guess they could supply some sort of Force Feedback... heck if Logitech can do it...

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.
:eek:
WOW!

if they think electronic brakes will be quicker, then why is electronic shifting so much slower?

so far nothing electrical on the car that was formally cable or hydraulic has been any better, IMO.

so far nothing electrical on the car that was formally cable or hydraulic has been any better, IMO.
The tunability is better with the electronic replacements, which is something they mention with these brakes.

http://www.channel4.com/4car/news/news-story.jsp?news_id=15444

http://www.channel4.com/4car/media/news/02-medium/electronic-wedge-brake.jpg


A radical new electronic braking system will dramatically reduce stopping distances and react in a fraction of the time of current hydraulic systems, according to its inventor Siemens.

Currently being tested by a number of European car makers, the electronic wedge brake, or EWB, works by using the momentum of the car to provide greatly increased braking power. When the driver hits the brakes, the pad is pushed into the brake disc by the wedge. The faster the car is travelling, the greater the force of the wedge on the brake pad. Seimens also says it requires mush less effort from the driver and is quicker to respond, which makes the EWB ideal in emergency situations. It reacts quicker because the EWB does not have to wait for pressure to build in the hydraulic fluid. Instead, a small electric motor pushes the wedge against the pad, taking about a tenth of the time of a hydraulic system. The motor runs off the car's 12-volt electrical supply and can use the stored energy in the car's battery when the engine is not running.

Another advantage of wedge brakes is that each wheel is slowed independently of the others, which allows the braking effort to be distributed more precisely. An electronic sensor monitors how much braking force is being passed through each wheel and acts as an anti-lock device to prevent skidding.

Tests of prototypes fitted with EWB wedge brakes have shown the system can bring a car to a halt in less than half the distance required by cars with hydraulic brakes. Manufacturers are keeping quiet about EWB's development, but it's thought Audi, BMW, Mercedes and Porsche are all working on it and expect to launch cars fitted with EWB in 2008

The tunability is better with the electronic replacements, which is something they mention with these brakes.

yes, but how realistic is it going to be? i havent seen very many tunable tiptronic parts on the market, or tunable DBW parts. Maybe for racing its great, and if thats what they are going for then I will shut up (since i didnt read the article), but i dont see it as any better for consumer cars.

Great. Now electrical problem = unstoppable car.

I was under the impression that stopping distance was more a function of the weight of the car and the friction with the road (tires & surface). A high performance brake kit like on an STI seemingly has enough force to lock up the wheels regardless of speed, so braking force isn't what limits the stopping distance, right?

So how could they possibly halt a car in half the distance by applying even more braking force? Maybe the electronic torque sensing control to prevent locking up the wheels makes more of a difference than the extra force. Or else there is something else I'm missing here.

Either way, I'm excited about better brakes. Bring them on.

Each corner would likely be independent of the others to facilitate stability control, so it would take a major central failure to loose braking force. Also, there will always be a backup system, like the emergency brake in current cars.

And I'm guessing pedal feel will be like electronic throttles; adjustable to different applications. I wouldn't be suprised if they add a solenoid/servo to the brake pedal to articulate certain feedback aspects.

Tom

yes, but how realistic is it going to be? i havent seen very many tunable tiptronic parts on the market, or tunable DBW parts. Maybe for racing its great, and if thats what they are going for then I will shut up (since i didnt read the article), but i dont see it as any better for consumer cars.
Completely different senario. A "tiptronic" transmission is simply an automatic trans with a more manual control of gear selection. It doesn't allow faster shifting without modifying the fluid passage ways or pressures.

it might sounds good in paper has anyone thought of what would happen if somehow somewhat a tiny pice of rock or dust could have interfer with the electronic motor? as the driver have no way to tell his/her brake is not working

I was under the impression that stopping distance was more a function of the weight of the car and the friction with the road (tires & surface). A high performance brake kit like on an STI seemingly has enough force to lock up the wheels regardless of speed, so braking force isn't what limits the stopping distance, right?

So how could they possibly halt a car in half the distance by applying even more braking force? Maybe the electronic torque sensing control to prevent locking up the wheels makes more of a difference than the extra force. Or else there is something else I'm missing here.

Either way, I'm excited about better brakes. Bring them on.

practical stopping distance is a function of tire grip first, and brake fade after that. Especially for performance cars, as the brakes are sized up a bit to handle heat transfer better. So long as a brake system has the capacity to absorb/transfer/radiate the energy fast enough, stopping distance is independant of car weight. Odd but true. If it was truly half the distance, the vehicle had undersized brakes to start with.

Brakes change kinetic energy into heat through friction. If they are limited in how fast they can do that (small pad/rotor size, pressure, material qualities, etc) then they can only stop so fast. It looks like this system could apply more pressure more quickly (and is self-energizing) to help reduce brake distances.

Something like this seems like it could easily be a retrofit to current cars;the rotor is likely the same, just a different caliper and a wiring harness and voila, a new brake system! If I were an aftermarket brake company I'd be jumping all over this.:)

Tom

it might sounds good in paper has anyone thought of what would happen if somehow somewhat a tiny pice of rock or dust could have interfer with the electronic motor? as the driver have no way to tell his/her brake is not working

If thier brake isn't working they'll know. ;) The motors would be enclosed, no worry. There are loads of federal requirements a new brake system would have to pass, not to mention OEM durability & safety testing.

Tom

if they think electronic brakes will be quicker, then why is electronic shifting so much slower?

so far nothing electrical on the car that was formally cable or hydraulic has been any better, IMO.

Are you talking in reference to manual shifting? Automatics shift slower to be smoother. they could bang of shifts (which would actually be more durable), but very few people want that (relatively).

Most manumatic racing transmissions (I'm thinking WRC here) shift much faster than a human could, but I don't know if they are hydraulic or solenoid based.

Tom

if they think electronic brakes will be quicker, then why is electronic shifting so much slower?

so far nothing electrical on the car that was formally cable or hydraulic has been any better, IMO.

What about electric radiators? One less belt needed, and no sapping of power from the engine. Electric steering is a great idea, but the feedback you get from the wheel (or lack of) needs to be addresses.

Also, you have to realize that most of these are 1st gen products - time is needed to improve them. I have absolutely no more trust in a plastic hose filled with fluid than I do with a circuit board attached to an electric motor.


And concerning your comment on transmissions - that is not valid. A true clutchless tranny with paddle shifters is many times faster in shifting than even the fastest professional driver.

well my point was simple. Consumer electronics in cars have never seemed to outdo hydraulics or cable (belts are another story). Even the transmission is still valid, because even if you compare it to the automatic tranny, a tiptronic is still slower. If electronics sped things up, then a tiptronic should still be faster the regular auto, just like the manutronic racing trannies are faster then a regular manual. Its simply consumers dont get that advantage.

the braking thing basically boils down to DBW and the electic steering like Hazdaz mentioned. I dont think there is anything to gain from electronic braking but you do lose the feel of the pedal, just like you lose the feel of the pedal for DBW. While it can be simulated, IMO, its about as good as a steering wheel and pedals for your computer, and I think we all agree those are not good enough for real world subsitutes. I dont see how this will help anything, while it may be a decent substitute, a claim of changing brakes forever is far-fetched.

But oh well, i dont rule the world so my opinion is merely my own.

wow roll eyes roll eyes x5

nasioc armchair engineers knows their sh.t as evidenced by this thread.

rooooooooooooooooolls own eyes

wow roll eyes roll eyes x5

nasioc armchair engineers knows their sh.t as evidenced by this thread.

rooooooooooooooooolls own eyes

what else do you want? :rolleyes:
im explaining my opinion, if you dont like it, dont read it. stop whining.

I wondered the same thing. I guess they could supply some sort of Force Feedback... heck if Logitech can do it...

hahaha... good one


Great. Now electrical problem = unstoppable car.

i totally agree. i dont know, theres just something about electronics that worry me. i mean yea, almost everything is controlled by a computer to some extent, but i feel like the ability for something to go wrong is just too easy. with a hydralic setup, everything is tangible. its not hard to take a look at a brake line to see if its leaking, etc.

as for electronics, so many things could go wrong without you knowing until its too late. yeah, you could have some sort of mechanical ebrake, but is that the only back-up? i wouldnt feel safe without redundant systems when things are electronically controlled, especially for something as important as your cars braking system. i just feel like it wouldnt be hard for a short or malfuntion to either cause your brakes to flat out fail or just randomly engage random wheels. i mean take a look at how many electrical components fail on so many german cars? audi/vw *cough cough* i definitly wouldnt want electronic brakes on one of there cars.

I agree Garwin. I actually am looking forward to the technology. I am quite sure by the time it is implemented it will be tested well enough that we should be able to be comfortable with it, not to mention I'm sure it will be designed to be fairly fault tolerant in itself. I see a number of benefits, one being the speed at which the system can operate, while being greater flexibility in placement and routing of system components. Electrical wires are much easier to locate than steel tubes which are to be bent a certain way, need X amounts of slack for articulation, etc.

I personally would like to see essentially all pulley driven components run in another fashion. It could be PTO-driven for all pumps perhaps or all could be elctronically driven. But I think the key is to figure out how to create better packaging. This is what I do every day, right now I am working on a small diesel, but it makes no difference what engine or what size, packaging is critical. It's not easy, but most often the easiest and most simple solution is the most ellusive as said by Jonathan Ive of Apple. He is so very right. Simple often breeds lighter weight and better packaging and strength.

I'll definitely give the Germans the thumbs up for trying many things before others. Have to have a winning spirit and will to be at the forefront.

Great. Now electrical problem = unstoppable car.

Seriously, they better have a mechanical backup system.

if they think electronic brakes will be quicker, then why is electronic shifting so much slower?

so far nothing electrical on the car that was formally cable or hydraulic has been any better, IMO.


I think that solenoid automatic transmissions are way way way way way way way better than the old ones.

Not a dig, but have you ever driven a pre-electronic automatic car?

What I'm more concerned with is how the human occupants would feel w/ this greater braking force! I'm excited and optimistic about it though - just like I am w/ Michelin's tweel.

Seriously, they better have a mechanical backup system.

:huh: Seriously, they already do.

Tom

This isn't about the electronics.

This is about the mechanical system they've developed that allows an electronic servo to press on the brakes with forces rivaling or surpassing that of hydraulic brakes. The friction of the rotor against the pad creates most of the force, while the servo merely controls it. Up until now, electric brakes have had to rely on brute force to push the pad and rotor together, often resulting in overheating servos in an already high-heat environment.

You will not be seeing electric brakes on every car on the road anytime soon. Drive-by-wire has been on the market for over 15 years, but we're just now seeing it start to saturate (under mandate, no less)... and it still sucks balls. Brakes, where control and feel are prized even more than with throttles, are going to be a hard sell on the american car-buying public.. not to mention the service sector.

If we do see these in widespread use anytime soon, it will be on haulers (18wheelers), where brake feel is already out the door (pneumatic brakes) and the drum brakes are in dire need of upgrade.

:eek:
WOW!

Yeah, what they failed to mention is that the hydraulic-brake car was shod with RE92's driving on wet broken ashphalt, and the EWB car had Hoosiers on dry concrete...

If ABS is engaging, you aren't stopping any shorter no matter what kind of brakes you have.

Yeah, what they failed to mention is that the hydraulic-brake car was shod with RE92's driving on wet broken ashphalt, and the EWB car had Hoosiers on dry concrete...

If ABS is engaging, you aren't stopping any shorter no matter what kind of brakes you have.

Well, but if this thing operates at much higher frequency with much finer modulation than traditional ABS, it might be more effective.