More on that runaway Prius...

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Actually, a lot of people know. They default to plain hydraulic brakes.
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On Fri, 19 Mar 2010 05:58:06 -0400, "Ed Pawlowski"

Unless they don't.
We are talking about a MALFUNCTION. Things often behave in unpredictable ways when they are malfunctioning.
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wrote:

Might loose braking on first application, worst case.
Now, a MECHANICAL failure in the ABS CAN make your brakes totally ineffective. Had the gear fall off the brake modulator motor on my '95 Pontiac TranSport and it made the rear brakes totally inoperative.
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On Fri, 19 Mar 2010 22:35:51 -0400, snipped-for-privacy@snyder.on.ca wrote:

No, the results may be completely and totally UNPREDICTABLE. You can't state how they will work when they are not operating the way they were designed to operate normally.

Are you now claiming that 2009 Toyotas have 1995 Pontiac braking systems in them, or that 1995 Pontiacs have 2009 braking systems in them?
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On Sat, 20 Mar 2010 08:22:00 -0400, snipped-for-privacy@dog.com wrote:

failure modes.. I've likely forgotten more about cars than you will EVER know.
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On Thu, 18 Mar 2010 22:07:22 -0400, "Ed Pawlowski"

Something may interfere with the pressure getting to the wheels. This is especially true of cars with ABS.
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You mean like an asteroid hitting the highway and bouncing up under the car. OK that could happen.
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On Fri, 19 Mar 2010 06:20:35 -0400, snipped-for-privacy@dog.com wrote:

activated braking is normal.
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On Fri, 19 Mar 2010 23:13:41 -0400, snipped-for-privacy@snyder.on.ca wrote:

Well, gee, Clare. What would happen if you were at highway speed and the computer malfunctioned and caused full accelleration along with reduced braking power? Maybe you just solved the mystery of why all these people are saying the brakes wouldn't stop the car even though they were "standing on the brakes".
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On Sat, 20 Mar 2010 08:26:35 -0400, snipped-for-privacy@dog.com wrote:

YOU explain to me how anything that could/would cause the throttle to go to WOT could have any effect on the ABS sytem - specifically cause a false lockup detection - or how anthing that could/would cause a false lockup detection on the ABS could cause the throttle to go to WOT.
Or even how a REAL lockup detection could cause the throttle to go to WOT - or how a real WOT condition could cause a false lockup detection.
The only thing that can and WILL cause reduced braking power at WOT is improper use of the brake. The brake MUST be applied firmly and steadily to a stop. IF YOU PUMP (or release) THE BRAKE, you HAVE LOST BRAKING POWER. There is NO MANIFOLD VACUUM at WOT.
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On Sat, 20 Mar 2010 18:13:19 -0400, snipped-for-privacy@snyder.on.ca wrote:

That's easy. It's called a MALFUNCTION.

That's easy. It's called a MALFUNCTION
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On Sat, 20 Mar 2010 21:20:51 -0400, snipped-for-privacy@dog.com wrote:

and therefore no INKLING of what infitesemely small chance there is of such a thing happening ONCE - much less dozens of times, as is alleged to have happened.
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On Sat, 20 Mar 2010 22:02:24 -0400, snipped-for-privacy@snyder.on.ca wrote:

Maybe you need to go look up the word MALFUNCTION. You seem to be a little fuzzy on what it means.
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On Sat, 20 Mar 2010 22:28:08 -0400, snipped-for-privacy@dog.com wrote:

FUNCTION first.
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On Sat, 20 Mar 2010 23:28:41 -0400, snipped-for-privacy@snyder.on.ca wrote:

I no longer believe that you do not drink.
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On Mar 20, 11:28pm, snipped-for-privacy@snyder.on.ca wrote:

Once again, you are dead wrong here. First, you don't know the specifics of how the actual ABS system is designed or works in the Prius. Without that, you are already speculating. Any car with ABS has a computer controlling the hydraulic pressure that is going to each wheel. The computer is looking for a wheel starting to lock up, at which point it reduces the pressure to that wheel to get it spinning normally again. So, tell us why a malfunction in the ABS computer could not command 2 wheels, or all 4 wheels to minimum pressure continuously? Have you not seen your own PC hang in some endless program loop?
Now I also remember you telling us how manufacturers are now making cars with only two computers and some have only one. You claimed some cars have the ABS, climate control, and radio all run off of one central computer. I've showed you this is a crock, complete with multiple links. You've provided nada. However, let's go with your claim that the engine computer and ABS are commonly co-mingled into one computer. So, now you have the computer that has malfunctioned in control of both the throttle and to a significant extent, also the brakes. Note, I am not saying this is a high probability event or that it explains what has happened in these runaway cars. But it's impossible to rule out. If you can do so, tell us exactly how it's impossible for whatever computer is controlling the ABS to not cause a loss of at least some braking capability during a malfunction.
Note, I still say IMO, the latest incident with Sikes is a hoax because of many other factors.
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On Sun, 21 Mar 2010 06:20:52 -0700 (PDT), snipped-for-privacy@optonline.net wrote:

I've seen PCs do that - but the ABS computer is a much simpler system with no GUI and only a single hard coded program which watches 4 incoming pulse trains and the brake light switch.and compares the frequency of those 4 pulse trains. If, with the brake light switch active, one excedes the frequency of any or all of the others, the circuit related to the signal with the lower frequency is activated, putting the ABS cuicuit for that wheel into effect. The ABS device shuts off the pressure from the master cyl to the accumulator for that brake circuit, and a motor winds the piston in that accumulator down to reduce the hydraulic pressure untill the wheel stops skidding (starts turning the same speed as the faster wheel) at which it reverses and puts the pressure back up till it reaches incipient lockup again - and continues to modulate the pressure untill the pedal is released. During this active phase, pushing harder on the brake cannot increase the hydraulic pressure on that circuit. If the pedal is released, when the accumulator piston comes back up the fluid returns to the master cyl wirhout pressurizing the brake circuit, the same as with non-abs brakes. If the pedal is released while the brake is in lockup, the fluid pressure is reduced and the accumulator returns to the full pressure position.. With any mechanical malfunction of the ABS causing one brake (or more) to not apply, the ABS warning light comes on and stays on until the vehicle is shut off. With any electrical or electronic failure causing an accumulator to stay in the low-pressure position, the ABS light is also turned on..
Nobody to this point has reported the brake warning light to be on. It would be a pretty complex failure mode that would affect all 4 wheels, not turn on the ABS warning light, and not be VERY evident when investigators check the vehicle. In other words, the chances of it happening and not being provable are EXTREMELY low.
So low as to be VIRTUALLY impossible.
Same with the regen braking control on a hybrid. When the grake pedal is depressed, without computer intervention the hydraulic brakes work normally. With the computer working and requesting regenerative braking the motor is switched to operate as a generator slowing the vehicle down, and if the pedal is pressed farther, they hydraulics come into effect.
From the way it has been described to me, there is NOTHING the computer can do to "shut off" the hydraulic braking system. And with the power control system calling for power, there is no way the regenerative braking system can also be engaged - impossible because of the way Hybryd Synergy Drive works. Using the same components for drive and braking, they cannot do both at once.
Impossible. And regenerative braking is initiated as soon as you lift your foot from the gas. Don't need to touch the brake at all. So the only viable scenario for reduced braking at WOT is improper emergency use of the brake. It MUST be applied FIRMLY AND STEADILY - WITHOUT RELEASE - otherwise vacuum boost is lost and brake pressure is reduced.. ANd on the Prius, because it can run without the gasoline engine running, there is a standby electric vacuum pump to give vacuum to the booster even with no engine vacuum - so on a hybrid that pump would ALSO need to fail in order to reduce the brake pressure.

I just explained how ABS works. Not impossible to lose SOME braking capability - but not without turning on a warning light and leaving evidence.
I'd say it is EXTREMELY unlikely the ABS has been involved in ANY way, in ANY of the reported ren-aways - Hybrid or otherwise. So small a possibility as to be statistically irellevent or virtually impossible.

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On Mar 21, 3:43pm, snipped-for-privacy@snyder.on.ca wrote:

Even simple computers can fail. Less likely yes, but that is different from saying it's just impossible. And how did it suddenly become so simple? You were telling us that the trend is that ALL the computing function is being centralized in one or two computers in cars today to save money. You specifically told us before that some cars have the same computer that is doing the ABS doing the climate control and the radio. So, how is it that now the ABS computer is just a simple computer looking at pulse streams? It should be monitoring the air temp, the outside air temp, sending the radio station identification to the radio display, responding to the driver turning the tuning knob, and God only knows what else. You said it was easy, practical and safe to develop cars that way. I said it was a crock.

I didn't see you make that qualification when you wanted to know how a computer could interfere with the braking, implying it was impossible. You've just answered your own question. A malfunctioning ABS computer could do it. Also, if the ABS computer is stuck in some unforeseen mode and not responding, what makes you think it's going to put the ABS light on?

I agree with that, but that is different from stating that it's impossible for the computer to compromise the braking, which is the argument I believe you were making.

That should give us all lots of confidence. Have you found that car where the ABS, climate control and radio all use one computer?

You just like going further and further out on a limb, don't you? I think you'd have a very hard time in court with a judge, where you have to separate what you know as a fact from here-say, opinion, and conjecture.

And you have such detailed knowledge of the design of the ABS computer, that you know it can't be stuck in some loop, not responding and also not setting the warning light? Somehow I doubt that.

I'd say it's extremely unlikely too. But then the runaway action is also only happening in a minuscule fraction of Toyota's millions of cars. But I'm content to wait for NHTSA to conduct a complete forensic investigation together with the car engineers, engineers from companies that made the subsystems, etc. That's how you get to the bottom of things.
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On Mar 19, 11:13pm, snipped-for-privacy@snyder.on.ca wrote:

And once again, that assumes the computer controlling the ABS is functioning normally. I thought the whole premise of the discussion was possible MALFUNCTIONS and whether they could affect operation. The ABS clearly has the ability to reduce the braking pressure to any wheel. By how much, I don't know, but I would suspect it would be a lot, as you might need to reduce it considerably to get a wheel to stop skidding. But worse case, if there was some bizarre bug that allowed it to happen, the computer likely could command reduced pressure on all 4 wheels continuously.
The probability that this is happening at the same time the engine computer is commanding full throttle would seem to be extremely low. Especially if they are run by two different computers. And it would likely also show up in the data stored on-board.
Just for the record, IMO the latest guy Sikes in San Diego is a lying skunk.
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On Mar 15, 11:55am, snipped-for-privacy@milmac.com (Doug Miller) wrote:

No, it wouldn't.
What people do is rather than stop the car right away and shut it down, they use the brakes to CONTROL or MAINTAIN a certain speed. The brakes quickly get HOT and quickly lose their effectiveness.
Burned brake smell means that those brakes are not going to do jack squat no matter how hard you push on them.
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