Brake enhancer for emergency stopping



Also, it only has to last 1/4 mile.
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Joseph J. Pfeiffer, Jr., Ph.D. Phone -- (505) 646-1605
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Ben Bradley wrote:

They run the car thru a pool of water, and then put 500 HP or so to it while the front brakes are on. The water lets the tires get spinning and soon there is a layer of melted rubber. Which gets the tires up to proper temperature for maximum grip.
More extreme than the heater I posted earlier upthread.
Nothing besides tire rubber on asphalt is going to be better.
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Ben Bradley wrote:

No "high friction goo stuff". They used to use bleach during the burn-out, which is just heating the tires by spinning them. Now they use plain water.

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Bob wrote:

I would be amazed if such a chemical can exist without being really bad for the environment.
The first thing you have to do is understand how a tire grabs the surface. Hint, it isn't what you learned in Physics 101. Tire grip is due to the energy that the tire uses to deform around the surface of the road. Think of the road as a sandpaper surface and the tire grabbing into the nooks and cranies.
Any goop is going to fill the nooks and cranies and decrease traction for a while, probably longer than the top will take.
How about a great light or flashbulb that can heat three quaters of the tire's surface up to optimal temperature?
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Serious R/C car racers have some stuff that they put on their tires for more grip. Other than that it exists, I don't know anything about it. Check in one of their forums, Google, etc.
JM
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On icy roads, you can use sand. On clean, dry roads, tires work really well, and any sort of grit or adhesive will become a lubricant.
In summer, you might try using a jet of compressed air or other gas to clean the road ahead of the tire. This could clear away water and sand to prevent hydroplaning and slipping.
-- Matt
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On Sun, 20 Nov 2005 21:18:37 -0500, "Matt Timmermans"

This brings up the idea of having some continuous sensor(s) evaluate (using methods beyond the scope of this post) the condition of the road, and when a "stop car fast" request is made, immediately decide what, if anything, to spray or release onto the tires or road to aid in friction. This gets by your point 3), in that it won't make the conditions worse, because it won't be released on inappropriate road conditions.

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The only way I can envision would be additional tires, or maybe a belt like a treadmill, tucked in the undercarraige of the car that deploy to increase the surface area of the road contact surfaces. This apparatus would then either have to have some kind of resistance to kinetic energy (flywheel, torsion) or a dynamic braking system too slow the vehicle.
Could be messy for the home mechanic working on his vehicle on jackstands and it deploys while he's under there!! :-(
-Will

clean
prevent
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@@ wrote:

The thing is, friction is proportional to the normal force, not to the contact area. All else being equal doubling the contact area does nothing. In the real world changing the contact area in either direction may increase, decrease, or have no effect on the frictional force depending on the details of what is happening at the contact surface. If the braking device used a different rubber compound optimized for stopping and not compromised to provide long service life it might allow for somewhat shorter stops, but I doubt that the gain would be really large.
I'm a bit puzzled as to what a flywheel or regenerative braking system would bring to the party, though, other than more weight and complexity in a system that is already too heavy and too complex.

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J. Clarke wrote:

Why a treadmill? why not just a big block of gumball rubber?

With a strong factor for coefficient of friction. In theory a big hunk of gumball could have a much higher coefficient of friction. In practice it won't, it will have lots of road dirt, oil, water, etc thrown up on it when not in use, so it will hurt. Plus it will add weight to the vehicle all the time, adding mass that must be slowed down. And hurting things like ride quality, gas mileage, etc.

either of these recover energy. They still rely on friction of tire to road, so they can't do more than brakes can. They are just different brakes, capturing some energy rather than throwing it all away as heat.
Pat
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Bob wrote:

Thinking about this, I think you're working the wrong end of the problem. The collision avoidance system should prevent a situation from arising such that increasing the static friction would be needed. This means making an ongoing assessment of the road surface and conditions and making allowances for a disparity of braking power between the CAS-equipped vehicle and the one ahead, as well as looking ahead of that vehicle and analyzing the traffic pattern to assess the possibility that it will collide with an immobile object.
Something that would IMO be highly beneficial would be an aft-looking analysis as well--stopping successfully in heavy fog for example is not the end of the game--to be safe you also need to clear the road surface completely as otherwise you risk being hit hard by something coming from behind (this is not an uncommon kind of collision in areas where heavy fog is frequent), and I think it would be worthwhile for the CAS to either do that or make a recommendation to the driver that it be done.
Now, someone may cut your CAS-equipped vehicle off and then manage somehow to stop suddenly, but in that case there would be only a narrow range of distances over which your increased-friction device would be of benefit--this would be an infrequently occurring scenario if your programming is good.
I think a more interesting problem is "edge of the road" analysis--seems to me your system should have "hit the ditch" as an option and that requires that it be able to assess the viability of the ditch as an escape zone.
As to how it's going to handle some idiot playing "chicken", I don't know if anybody has every come up with a proven survival strategy for that game.
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Bob wrote:

That's called a "sander". Locomotives have had them for a century.
                John Nagle
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Have you tried Wiley Coyote?
| -]
Dale

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Dale Stewart wrote:

Now there's a thought--a device that paints a tunnel in whatever you're about to hit so that you can drive through the tunnel <g>.

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On Wed, Nov 23, 2005 at 06:45:23AM -0500, J. Clarke wrote:

Jeez, the quality of this group is really going downhill. Everyone knows that the tunnel, once painted, only works for RoadRunner himself. Once you (Wiley) attempt to pass, you smack into said object. Come on - do some research and get your facts straight! :-)
-Brian
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Isn't that just the Acme brand paint that does once through thingie, right?
Come to think of it, there's probably an Acme Brake Enhancer you could order. It too would depend on who was trying to use the brakes. ;)
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Randy M. Dumse
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J. Clarke wrote:

Of course we should do everything reasonable to prevent an accident in the first place. But that is not always possible. I don't think you would argue for the elimination of seatbelts and airbags. Safety systems need to be designed with multiple layers.

Yes, this is a very good point. If the aft-looking radar detects a vehicle approaching too fast from the rear, it could turn on a pair of narrow beam strobe lights bright enough to penetrate the fog/rain. A pair is necessary to give the approaching driver enough perspective to judge distance, and a pulsing strobe grabs attention better.
If that fails, then I think your suggestion of pulling off the road completely is a good idea. That will require the computer to monitor the condition of the shoulder, but that shouldn't be too difficult, since it will already be monitoring adjacent lanes.
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Bob wrote:

The problem is whether it can detect a deep ditch that would result in a rollover, or an obstacle covered by tall grass, or very soft mud, or for that matter high water.
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Seriously, though...
It's just good old Chlorox (bleach).
The dragsters used to spin out in the "bleach box" to warm their tires, and the bleach both cleaned and softened the rubber surface. I've heard you can use bleach to get more traction on ice as well.
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