Dale
 I can tell you from experience that the Audi problem was real. I

 don't know what the problem was but it wasn't small close peddles.
 I had an Audi and experienced an uncommanded acceleration.  Here
 is what happened.  I turned a corner on a city street and started
 to accelerate and the car throttle body went "Wide OPEN"  the
 RPM went   to about 6K.  I stood on the brakes and it was still
 accelerating
 and about to hit the car in front of me so I kicked the transmission
 into neutral and without a load the engine RPMs pegged for a split
 second and then dropped back down to idle.  I parked the car on
 the side of the road and called the local Audi dealer... Keep in
 mind it was "Not" under warrantee. They immediately picked it up,
 gave me a free rental and fixed it for free.  Oh, this was the
 4000S model and not the 5000 model car that was suppose to have
 the "Problem".  I don't know what was wrong with it but I do know
 it wasn't "peddles"

 Mike C.

 Not necessarily calling bs, but I don't get it.  There's not a car
 made that can accelerate as fast as it can decelerate.  That
 implies  that the brakes are able dissipate more energy than the
 engine can  deliver.  I believe the engine might have gone to WOT,
 but I have a  tough time understanding how the brakes wouldn't be
 capable of still  hauling the car to a stop.  One factor is that if
 the engine is at  WOT and you pump the brakes, the booster would
 quickly lose vacuum  and so you'd be without the brake assist. It
 might take a heavy foot  to get much braking effort, but the same
 braking power would be available.  And, I can imagine that it would
 be surprising as well..

 Matt-

 I have not tried it Matt but one can "fade" the brakes.
 This is when the pad material gets so hot the coef. of friction
 goes  way down. It is a runaway situation. The longer you hold the
 pedal
 down with full power the worse the brakes get. Also brakes boosters
 work on vacuum. WOT vacuum is near atmospheric pressure.

 Brake fade is very common in road racing. One of the first things
 you need to do to convert a car to a road race car is upgrade the
 brakes.

 Paul Lamar

 --
 I doubt my situation caused any brake fade as it was over in less
 than 5 sec... I was on a 30 MPH zone and only about a car link and
 a  half from the car in front so by the time I stepped on the brake
 the
 distance was closing very fast and I immediately went into
 neutral... It was over very fast,... I remember starting to change
 direction toward the curb to steer around the car as I threw it
 into  neutral... No Idea what caused it but it was real.  Not that
 the  following has anything to do with the "Audi issue" but for the
 Prius
 problems... I personally think that there might be some EMI
 issues... They certainly don't shield those cars or test them to
 the  level we do in Aerospace and I bet they have missed a corner
 EMI  condition... Which would explain the "Ghost" in the system.

 Mike C.

 In a road racing situation the brakes can fade in a fraction
 of a second. You come into a 20 MPH corner at say 80 MPH (117 FPS)
 and stand on the brakes.

 The brakes can fade in 100 feet. Of course if you did not
 brake then that cannot happen. That scenario is for those people
 that tried to stop the car by applying the brakes.

 Paul Lamar

 Trying to back out of a parking stall and putting it in reverse
 says brake fade was not an issue. Mike's problem could be different.
 A lot of heavy brake use precedes brake fade. Three laps of the old
 Edmonton International Speedway
 (remember that one Paul. I corner marshalled a few times when the
 Chapparal was there) and my RX 3 had no brakes. 130 MPH into corner
 one. Yah it can happen quickly, usually on a heavy car and a down
 hill. Drag racers used to brake torque to warm the rear tires. Held
 the brake to the floor and the gas pedal to the floor. They usually
 backed off the rear brakes a bit so they did not hold as well. Then
 they could really melt the rear hides. The front brakes still held
 the car back. I still say the brakes SHOULD hold the car back. I
 could see some creep, but not the unimpeeded acceleration described.
 If this did happen, the brakes should be really hot when the car
 comes to a rest at the end of the event.

 Dale Davies

 I think the term unintended acceleration applies to a wide variety
 of situations. I agree that from a dead stop the brakes should hold
 the average car from moving as there is no real energy going into
 the brakes. The lady in the parking lot could be faulted for not
 putting
 her foot on the brakes when she selected reverse but how many
 of us really do that all the time?

 Paul Lamar

 With an auto trans??? Aways!!!

 Dale Davies




Modern cars with autos TX won't let you get out neutral without your
foot on the brake.  The gear selector is locked.

Matt-

Maybe that law suite caused that change. That happened years ago.

Paul Lamar

One problem not mentioned so far is that almost all current vehicles have
ABS.  This on/off/on cycling during a hard stop must generate a great amount
of heat which I'm sure has been compensated for by the manufacturers.  But
have their design parameters considered the addition of full power applied
during the stop?

Joel

Back in the old days GM used to test auto tranies by jerking
them into reverse at maximum burn out :) Roughly 30 MPH.

If it survived six of these in a row it was deemed
good to go.

Paul Lamar



Now I know what I'll do with the next rental car I get...  :)


Matt-