• Nov 10, 2006

Could technology from an 18th century horse & buggy become the latest high-performance braking innovation? Back then, they used a wedge of wood to bring the wheel to a stop. Since then, we have been through several innovations in braking, with the latest being with multi-piston calipers, squeezing ceramic-carbon rotors with a multitude of brake pad formulations. According to Siemens, the future of braking technology is called EWB or Electronic Wedge Braking. Along with a claim that they have regularly experienced braking distances that are less than half of what's required by standard brakes, they also claim to utilize less than 10% of the energy needed by hydraulic brakes and weight substantially less than their conventional counterparts. What's more, the EWB will eliminate the need for brake lines, a servo-unit and a brake fluid reservoir, as it is entirely driven by 12-volts of electricity.

Here are a couple of other really cool features of the system. The faster the vehicle is traveling when the brakes are applied, the more powerful the brakes immediately become. The rotor momentum draws the pad further up the series of interlocking wedges applying progressively more pressure and increasing efficiency. Each wheel can also be electronically modulated to allow for much more precise anti-lock and stability processes as well as eliminating the pulsating pedal associated with the current ABS systems.

When will the EWB system hit the road? Possibly as early as 2008 on a Porsche, BMW, Audi or Mercedes-Benz.

[Source: AutoWeek]

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  • 24 Comments
      • 8 Years Ago
      #23 - The difference in a Porsche 911's stopping distance and a full size SUV is so drastic that if the SUV is following the Porsche somewhat closely on the interstate and the Porsche driver applies full braking force, there's going to be an accident regardless.

      As braking distances get continually shorter, reaction times will play an even greater role in determining total stopping distance.
      • 8 Years Ago
      I find this technology very interesting, but am concerned about the limits of the tires in addition to the breaks. I'm always an early adopter, so I would see no problem checking the option box to update the breaks to these - but I have had a number of rear-end collisions where the drivers behind me are not paying attention during LA rush hour - I would worry that I would have more rear-end collisions due to a reduced stopping distance for my vehicle.

      James
      http://www.cartv.com
      • 8 Years Ago
      I find a 50% reduction in braking distance hard to swallow. On many vehicles, your braking potential isn't limited by the brakes, rather the friction of the tires and the road. It's the same reason that using 14 pistons on a caliper is silly- locking up your rotors (therefore your tires) isn't going to slow you down any quicker. Modulating that will help, but in the end you're limited by tires more often than your brakes.
      gkz
      • 8 Years Ago
      safety issues aside (which i'm sure would be taken care of before production use), this would be a pretty cool thing to have. probably not long til you see them on race cars.
      • 8 Years Ago
      If the energy is applied in reverse it would work in an emergency situation. Example, when you turn on the engine and the alternator is juicing up the car the energy is used to depress the brake. So when there is no electricity the brakes are applied at lets say 25%, that is their resting position. It would be an automatic parking brake as well.
      • 8 Years Ago
      Actually, in my experience, it's probably easier to create a super-reliable electrical braking system than a similarly-reliable hydraulic system. Just because auto manufacturers haven't yet put the same amount of effort into electrical reliability doesn't mean it can't be done.

      For example, it's fairly straightforward to create a second, temporary electrical supply that is used as a backup for critical systems (does your PC have a UPS? Then you know what I'm talking about). It'd be far more difficult to have a second, separate hydraulic system to account for possible brake line failure.

      Your car probably already has some similar technology in place: Many airbag systems have small built-in power backups, so the airbags will still deploy properly - even if the car battery is destroyed before the full impact of an accident is enough to trigger the airbags. This is also the reason you'll see warnings to disconnect the battery - and then wait a period of time (I've seen specs claim half an hour!) before working on the airbag system.
      • 8 Years Ago
      Reduced latency? BMW is using a system where if you rapidly lift off the throttle, the brake calipers are primed by the ABS modulator, so that the response is quickened.

      50% reduction is just as likely as the '30 meter car' project-100kph-0 in 30 meters, for an average deceleration ob about 1.3g. (peak deceleration of cars like McLaren SLR-air brake, Ferrari Enzo-peak downforce around 140mph)
      • 8 Years Ago
      "eBraking Cuts Stopping Distance 50%"

      Ha! I could claim that before Siemens could.

      Descending any sort of downhill grade, the brakes on my 1984 Chevy Cavalier wagon would fade into obscurity in less than a minute. The solution? Pull the e-brake, cut stopping distances in half! :-)
      • 8 Years Ago
      Did anyone (#1-#12, ecxept #6) see the video?
      if so enough of the power falure and
      I think the system is as tuneable as an ECU
      on how much power you want the brakes to have or which ones you want to have the most power front or back brakes...
      • 8 Years Ago
      Are electronic brakes really that much less reliable than hydraulic brakes? In a total hydraulic failure, you're equally without brakes. Not completely in either case, the Emergency-brake(Hint: total hydraulic or electric failure on the road would be considered an 'emergency') is usually cable-actuated by your arm muscles...
      • 8 Years Ago
      The mechanical / hydraulic emergency brake wouldn't need to go away just because the main brakes are electronic.
      • 8 Years Ago
      Sam, the recall by mercedes was for a electric/hydraulic system. http://www.aa1car.com/library/2004/bf110412.htm

      This is a different animal. Electronic wedge brakes require no hydraulic lines or pressure accumulators. The pressure accumulators are suspected to be the weak link in Mercedes' system.


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