From: Tegger on
Mark <makolber(a)yahoo.com> wrote in news:7e7aec70-aaca-452d-af0d-
7ae36cf2a4de(a)o16g2000vbf.googlegroups.com:

> OPEN LETTER TO TOYOTA
> POST THROTTLE CONTROL SOFTWARE ON THE INTERNET FOR WORLD WIDE REVIEW
>
> Toyota has announced a fix for the accelerator problem. The fix
> consists of a shim. This is purely a mechanical change implying the
> problem is purely mechanical. A large part of the system consist of
> electronics hardware and software.
>
> Many doubts remain that the problem is purely mechanical. It is very
> easy for a subtle flaw to exist in software and electronics systems
> that can take many years to uncover.




The fix is not only mechanical. Toyota is also revising its PCMs so that
simultaneous brake/gas application results in the engine's power being cut
back, the opposite of what happens now.

So far there is no evidence that any of the unintended acceleration
incidents are due to anything more than mechanically-stuck pedals, or to
pedal misapplication.

If you're that concerned about unintended acceleration, you may want to go
after Ford as well. They account for 28% of all unintended acceleration
incidents.


--
Tegger

From: Paul Hovnanian P.E. on
Tegger wrote:

> Mark <makolber(a)yahoo.com> wrote in news:7e7aec70-aaca-452d-af0d-
> 7ae36cf2a4de(a)o16g2000vbf.googlegroups.com:
>
>> OPEN LETTER TO TOYOTA
>> POST THROTTLE CONTROL SOFTWARE ON THE INTERNET FOR WORLD WIDE REVIEW
>>
>> Toyota has announced a fix for the accelerator problem. The fix
>> consists of a shim. This is purely a mechanical change implying the
>> problem is purely mechanical. A large part of the system consist of
>> electronics hardware and software.
>>
>> Many doubts remain that the problem is purely mechanical. It is very
>> easy for a subtle flaw to exist in software and electronics systems
>> that can take many years to uncover.
>
>
>
>
> The fix is not only mechanical. Toyota is also revising its PCMs so that
> simultaneous brake/gas application results in the engine's power being cut
> back, the opposite of what happens now.

And all the left foot brakers are going to sh*t bricks!

> So far there is no evidence that any of the unintended acceleration
> incidents are due to anything more than mechanically-stuck pedals, or to
> pedal misapplication.

Better solution (for future reference): Build an accelerator pedal with a
microswitch attached to the pedal surface. If the driver lifts their foot,
the microswitch circuit (independent of the pedal position sensor) disables
the throttle plate drive system (torque motor, solenoid, or whatever they
use) so that the return spring closes the throttle. You'd have to lock this
out with a cruise control engage signal, but other than that, it would be
redundant to the electronic controls.

--
Paul Hovnanian paul(a)hovnanian.com
----------------------------------------------------------------------
Have gnu, will travel.
From: Jim Thompson on
On Tue, 02 Feb 2010 11:22:07 -0800, "Paul Hovnanian P.E."
<paul(a)hovnanian.com> wrote:

>Tegger wrote:
>
>> Mark <makolber(a)yahoo.com> wrote in news:7e7aec70-aaca-452d-af0d-
>> 7ae36cf2a4de(a)o16g2000vbf.googlegroups.com:
>>
>>> OPEN LETTER TO TOYOTA
>>> POST THROTTLE CONTROL SOFTWARE ON THE INTERNET FOR WORLD WIDE REVIEW
>>>
>>> Toyota has announced a fix for the accelerator problem. The fix
>>> consists of a shim. This is purely a mechanical change implying the
>>> problem is purely mechanical. A large part of the system consist of
>>> electronics hardware and software.
>>>
>>> Many doubts remain that the problem is purely mechanical. It is very
>>> easy for a subtle flaw to exist in software and electronics systems
>>> that can take many years to uncover.
>>
>>
>>
>>
>> The fix is not only mechanical. Toyota is also revising its PCMs so that
>> simultaneous brake/gas application results in the engine's power being cut
>> back, the opposite of what happens now.
>
>And all the left foot brakers are going to sh*t bricks!
>
>> So far there is no evidence that any of the unintended acceleration
>> incidents are due to anything more than mechanically-stuck pedals, or to
>> pedal misapplication.
>
>Better solution (for future reference): Build an accelerator pedal with a
>microswitch attached to the pedal surface. If the driver lifts their foot,
>the microswitch circuit (independent of the pedal position sensor) disables
>the throttle plate drive system (torque motor, solenoid, or whatever they
>use) so that the return spring closes the throttle. You'd have to lock this
>out with a cruise control engage signal, but other than that, it would be
>redundant to the electronic controls.

Did good design practice get lost over the years?

Back in the late '60's, when I was involved with cruise controls,
touching gas OR brake pedals, hitting turn signals, just about
anything, sent the throttle back to closed... all done with vacuum
motors :-)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
From: Paul E. Schoen on

"Paul Hovnanian P.E." <paul(a)hovnanian.com> wrote in message
news:2e2dnUh64MOD5vXWnZ2dnUVZ_rGdnZ2d(a)posted.isomediainc...
> Tegger wrote:
>
>> Mark <makolber(a)yahoo.com> wrote in news:7e7aec70-aaca-452d-af0d-
>> 7ae36cf2a4de(a)o16g2000vbf.googlegroups.com:
>>
>>> OPEN LETTER TO TOYOTA
>>> POST THROTTLE CONTROL SOFTWARE ON THE INTERNET FOR WORLD WIDE REVIEW
>>>
>>> Toyota has announced a fix for the accelerator problem. The fix
>>> consists of a shim. This is purely a mechanical change implying the
>>> problem is purely mechanical. A large part of the system consist of
>>> electronics hardware and software.
>>>
>>> Many doubts remain that the problem is purely mechanical. It is very
>>> easy for a subtle flaw to exist in software and electronics systems
>>> that can take many years to uncover.
>>
>>
>>
>>
>> The fix is not only mechanical. Toyota is also revising its PCMs so that
>> simultaneous brake/gas application results in the engine's power being
>> cut
>> back, the opposite of what happens now.
>
> And all the left foot brakers are going to sh*t bricks!

I wonder how many of those who had accidents caused by a stuck accelerator
use left foot braking? But ever since about 1970 I've always had manual
transmission vehicles, and I've only sometimes accidentally done some left
foot braking when I'm driving an automatic and I reflexively try to push
the clutch pedal to the floor. Of course it's actually the left side of the
wide brake pedal and results in a bit of a sudden stop.

>> So far there is no evidence that any of the unintended acceleration
>> incidents are due to anything more than mechanically-stuck pedals, or to
>> pedal misapplication.
>
> Better solution (for future reference): Build an accelerator pedal with a
> microswitch attached to the pedal surface. If the driver lifts their
> foot,
> the microswitch circuit (independent of the pedal position sensor)
> disables
> the throttle plate drive system (torque motor, solenoid, or whatever they
> use) so that the return spring closes the throttle. You'd have to lock
> this
> out with a cruise control engage signal, but other than that, it would be
> redundant to the electronic controls.

Part of the problem is people who can only think of one way to stop a car.
And also one way to make it go, by flooring the accelerator. In my manual
transmission vehicles, I would also release the clutch (if compression
braking wasn't doing the job), and shift to a lower gear through neutral.
In normal, non-aggressive driving, it should be readily apparent that the
accelerator is sticking and you should have enough time to use alternate
methods.

I've had a sticky accelerator and I just hooked my foot behind it and
pulled it up. Mostly just because it was idling too fast, and it was
usually that the carburetor cable and linkage needed lubrication, although
I think it was a floor mat problem once or twice.

There have been news advisories telling people to put the car in neutral if
this happens. Duh. And they advise not to shut the engine off, because
(they say) you may lose steering or braking. You might lose the power
assist, but there are mechanical backups (at least there used to be). And
if the transmission is still in gear, the hydraulic system will probably
still operate. But then I'm thinking of a manual tranny, or some automatics
that have a rear pump. And also newer vehicles might have these systems
under computer control, which might shut down with the ignition switch off.
And of course if you turn the switch all the way, the steering lock might
engage.

Yes, this is a serious problem, but I'll bet many of the accidents were the
result of a failure in the most important piece of hardware in any vehicle,
the "nut" behind the wheel.

Paul



From: Paul E. Schoen on

"Martin Brown" <|||newspam|||@nezumi.demon.co.uk> wrote in message
news:lI1an.31877$Fm7.15358(a)newsfe16.iad...
> Paul Hovnanian P.E. wrote:
>> Tegger wrote:
>>
>>> Mark <makolber(a)yahoo.com> wrote in news:7e7aec70-aaca-452d-af0d-
>>> 7ae36cf2a4de(a)o16g2000vbf.googlegroups.com:
>>>
>>>> OPEN LETTER TO TOYOTA
>>>> POST THROTTLE CONTROL SOFTWARE ON THE INTERNET FOR WORLD WIDE REVIEW
>>>>
>>>> Toyota has announced a fix for the accelerator problem. The fix
>>>> consists of a shim. This is purely a mechanical change implying the
>>>> problem is purely mechanical. A large part of the system consist of
>>>> electronics hardware and software.
>>>>
>>>> Many doubts remain that the problem is purely mechanical. It is very
>>>> easy for a subtle flaw to exist in software and electronics systems
>>>> that can take many years to uncover.
>>>
>>> The fix is not only mechanical. Toyota is also revising its PCMs so
>>> that
>>> simultaneous brake/gas application results in the engine's power being
>>> cut
>>> back, the opposite of what happens now.
>>
>> And all the left foot brakers are going to sh*t bricks!
>
> Darwinian evolution in action. Gas to go brakes to slow.
>
> It seems reasonable to me that if you hit the brakes hard enough to
> trigger ABS then the engine should back off from full throttle - even if
> the throttle hardware is stuck wide open. Loss of servo assist vacuum and
> then brake fade otherwise follows fairly quickly.
>>
>>> So far there is no evidence that any of the unintended acceleration
>>> incidents are due to anything more than mechanically-stuck pedals, or
>>> to
>>> pedal misapplication.
>>
>> Better solution (for future reference): Build an accelerator pedal with
>> a
>> microswitch attached to the pedal surface. If the driver lifts their
>> foot,
>> the microswitch circuit (independent of the pedal position sensor)
>> disables
>
> Trouble is your safety device would end up being the weakest link and
> failure to respond to a genuine throttle request when overtaking could be
> just as serious.
>
>> the throttle plate drive system (torque motor, solenoid, or whatever
>> they
>> use) so that the return spring closes the throttle. You'd have to lock
>> this
>> out with a cruise control engage signal, but other than that, it would
>> be
>> redundant to the electronic controls.
>
> How about a panic button in the middle of the dashboard that the people
> can hit when they are out of control which suspends engine power?

Here are some interesting videos that go into some technical details:
http://www.autoblog.com/2010/01/29/video-in-depth-look-at-toyotas-sticky-accelerator

I've also resumed the posting to include s.e.d.

Paul