Brake in Half the Distance You Do Now!

[XB70]

A Revolution in Braking is about Siemens’ Electronic Wedge Brakes (EWB) which, "In exercises that involved the cars braking from 62mph, the prototype with the wedge brakes regularly required less than half the distance to come to a complete standstill than the prototype with the standard brakes."

 

[obbop]

Give your conveyance a wedgie?

 

[WishIhadatruck]

It seems hard to believe your tires would have enough extra grip to stop in half the distance even if your brakes were better. I've read about these types of brakes in the past and they sound like a great idea but their claims are hard to believe for me. I'll believe it when I see it independently tested.

 

[XS650]

Quote:

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. I'll believe it when I see it independently tested.

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I won't, I'll know the test was rigged.

They are called the laws of physics, not the suggestions of physics.

Now, if their device doubles the co-efficient of friction between the tire and the pavement, I could be proven wrong.

 

[unDummy]

Yep, braking is limited to the rest of the vehicle. Great brakes + bad tires doesn't stop you too short.

But, they say that the brakes 'apply' faster. That will help everybody spill their coffee quicker. Doesn't some Mercedes apply the brake pedal if you release the gas pedal too quickly? Add this to the list of driver enhancement acronyms!

We need this technology to help make up for drivers with no skills, and to make up for those drivers enhanced with GPS, coffee, cell phones, laptops, DVD players, screaming kids, books.........

When you get rearended by someone reading a book, or broadsided by someone on the cell phone, you really hate all those new fancy techno garbage that does NOT prevent accidents, but adds to.... vehicle cost, vehicle weight, and owners' psychological indestructability.
I have ABS, VSC, AWD, TC, dozen airbags, 3rd brake lights, seatbelts, 2+tons of vehicle mass, EBD,.... and I don't even need to know how to drive! It reminds of that car insurance commercial!

They should market the technology, "new fancy acronym allowing you NOT to pay attention some more while you're driving".

Darwin anyone?

 

[rpn453]

It claims that it improves pad-to-rotor reaction time by 1/20 of a second. This doesn't seem significant considering overall reaction time for the driver can be a half-second or more.

I'm also not sure how they sabotoged the brakes and tires on the A6 with "conventional disc brakes" to extend its braking distance to twice what it should be. They'd provide real numbers if they are legitimate.

 

[Reg# 43897]

Quote:

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Quote:

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. I'll believe it when I see it independently tested.

---

I won't, I'll know the test was rigged.

They are called the laws of physics, not the suggestions of physics.

Now, if their device doubles the co-efficient of friction between the tire and the pavement, I could be proven wrong.

---

I am assuming that you are kidding on the last!

Looks like a bunch of foolishness to me. Brake lag is something that only concerns air brake systems as far as I am aware. Could be wrong.

John.

 

[wantin150]

"What’s more, the faster you are traveling when they are applied, the more powerful they become. When the pad meets the disc, the momentum of the rotating disc draws the pad further up the interlocking series of wedges, applying greater braking pressure and increasing retardation."

This is probably the reasoning behind the claim for half the braking distance. Same pedal pressure (or I would gather from the article) results in greater braking force which, would stop the vehicle faster than a vehicle with conventional brakes at the same pedal force.

Interesting in it's idea. Reduced vehicle weight, fewer components. Definite increase in computer complexity and the need for an additional battery.

 

[Da Game]

Quote:

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Yep, braking is limited to the rest of the vehicle. Great brakes + bad tires doesn't stop you too short.

But, they say that the brakes 'apply' faster. That will help everybody spill their coffee quicker. Doesn't some Mercedes apply the brake pedal if you release the gas pedal too quickly? Add this to the list of driver enhancement acronyms!

We need this technology to help make up for drivers with no skills, and to make up for those drivers enhanced with GPS, coffee, cell phones, laptops, DVD players, screaming kids, books.........

When you get rearended by someone reading a book, or broadsided by someone on the cell phone, you really hate all those new fancy techno garbage that does NOT prevent accidents, but adds to.... vehicle cost, vehicle weight, and owners' psychological indestructability.
I have ABS, VSC, AWD, TC, dozen airbags, 3rd brake lights, seatbelts, 2+tons of vehicle mass, EBD,.... and I don't even need to know how to drive! It reminds of that car insurance commercial!

They should market the technology, "new fancy acronym allowing you NOT to pay attention some more while you're driving".

Darwin anyone?

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My sentiments exactly. About 2mo ago a female drive cause a accident on the highway which resulted in the death of another driver, she was only issued a citation for violating the cell phone law.

 

[Shannow]

If the genuinely have used the pedal pressure to determine the parameters under which the brakes are tested then it's a crock.

It's a crock anyway. one G is one G, and cars get pretty close to that (or even a little over it)

 

[1040 WreckerMan]

On topic, the numbers don't seem reasonable to me. The biggest factor are the coefficient of friction between the brake lining and braking surface and between the tires and road.

Why do we keep making more devices to do what we used to do? Why can't we teach people instead of making our cars, phones, houses, etc. smarter. Learn to drive, problem solved.

 

[XS650]

Quote:

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If the genuinely have used the pedal pressure to determine the parameters under which the brakes are tested then it's a crock.

It's a crock anyway. one G is one G, and cars get pretty close to that (or even a little over it)

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Do you mean they don't actually get 2 Gs with their magic wedgie?

 

[n8wvi]

For me, the only believable distance reducing technology to come along recently is EBD. In a correctly working EBD system, how could you possibly stop NOTICABLY shorter without different tires?

Dave

 

[biomed_eng_2000]

"the prototype with the wedge brakes regularly required less than half the distance to come to a complete standstill than the prototype with the standard brakes."

Their statement above could be 100% true. They never said if the braking test was compared on the 1st stop or the 100th stop where the brakes would be extremely hot.

What are the factors that could have legitimately made that 2X stopping distance difference? Here are my guesses:

1. Maximum disk/pad forces - The wedge may be able to apply a higher maximum braking force such that when the disk/pad interface gets extremely hot, fade can be pushed to higher temps.

2. Brake Fluid boiling at temps vs Electronics not - boiling brake fluid will limit and/or delay the max force that the calipers can apply.

3. Speed - already mentioned in the article

4. Faster ABS pulsing - Perhaps this electronic control can pulse the ABS at 10X the rate of the hydraulic system. Since this is ultimately a feedback loop system, higher sampling and faster control can lead to shorter stopping distances.

5. Human feedback - most "non-enthusiasts" do not know that they are supposed to "lay into" the brakes when the brake pedal is pulsing. This electronic system may isolate the driver from the braking feedback. Of course, purists and racers may not like this isolation, however, for 95% of regular driving public, it may be safer.

6. others?