From: jim beam on
On 03/06/2010 09:03 AM, Jeff Strickland wrote:
> "jim beam"<me(a)privacy.net> wrote in message
> news:fvudnV-hwr-Z6A_WnZ2dnUVZ_rednZ2d(a)speakeasy.net...
>> if you buy all this fear-mongering idiocy that electronic throttle is a
>> problem, and that brakes, transmissions and ignition kill switches can all
>> simultaneously fail causing a driver to lose control, it might be worth
>> auto manufacturers of all stripes to adopt a slightly different
>> implementation of electronic throttle [e.t.] - if not for mechanical
>> reasons, but to shut the idiots up.
>>
>> first, lets understand e.t. functionality:
>>
>> 1. open the throttle when demanded
>> 2. close throttle when demanded
>> 3. allow "demand" to account for additional requirements like
>> a. de-throttle on shifting for automatics,
>> b. throttle appropriate to load at high demand [eg. full throttle at low
>> rpms can choke an engine and significantly reduce output - thus
>> de-throttle until revs support full open]
>
>
> The functionality is even easier than that -- open the throttle plate when
> the gas pedal is pressed and close the throttle plate when the gas pedal is
> released. You can get bogged down in semantics if you want, but the
> functiionality is really that simple Go when the pedal is pressed and stop
> going when the pedal is released. At the end of the day, anything else is a
> variation on pushing the pedal down or releasing the pedal so that it comes
> back up.

yeah, that meets conditions 3.a & 3.b. oh, wait, no it doesn't.


>
> When or why one might press or release the pedal has no bearing on the
> discussion. The only thing that matters is the expecation that the car goes
> faster when the pedal is pressed and stops going faster when the pedal is
> held at a mid-point, and slows when the pedal is released.
>
> When the throttle control system does those things, then it is doing its
> job.

why is it that people that don't know what they're talking about insist
on having "opinions"?


--
nomina rutrum rutrum
From: Cameo on
"Jim Warman" <mechanic(a)telusplanet.net> wrote:
>
> Have we seen problems with Fords drive by wire? A very few, but
> yes.... No unintended accelerations have been (AFAIK) documented.

Have we seen problems with Toyota outside of the US? Are they making
different cars for other markets?

From: Jeff Strickland on

"Ed Pawlowski" <esp(a)snetnospam.net> wrote in message
news:t8-dnSKUoI80LA_WnZ2dnUVZ_sqdnZ2d(a)giganews.com...
>
>
> "Jim Warman" <mechanic(a)telusplanet.net> wrote
>> Drive by wire throttle is a natural progression (if you can't see where
>> the future of the automobile is going - I feel sorry for you). It allows
>> for precise (hopefully) control of any electronic stability features, It
>> allows for torque limiting when appropirate... reducing the need for
>> other traction control measures (such as active brake booster
>> application) when necessary...
>>
>> Fords system relies on redundancy... I'm not a Toyota tech so I can't
>> tell you what they do... Fords system has three inputs..(one of them is
>> inversely proportional). If the inputs aren't "coherent", the car will
>> remain at idle...
>
> Drive by wire is certainly a natural progression. What failed is two
> things. One is the Toyota system (whatever that was), and driver training.
> Emergencies do happen and a driver should be competent enough to shift
> into neutral. Fail safe and redundancy should be part of any throttle
> system, but even that can fail, as have the simplest of mechanical
> systems.


All of this is fine, but ignores the fact that wrong-pedal accidents happen
in a very short span of time -- the old lady pulls into the parking space
and mashes the gas which sends the car through the front of the store.

The problems that Toyota has involves people driving along for miles -- the
CHP officer and his family went for more than 5 miles before the car
crashed. A passenger in that car called 911 from his cellphone, have you
ever called 911 from a cellphone? It takes a long time to get an answer,
then the system tells you to press 2 for spanish or hold, then you have to
wait from there for the operator to pick up. The passenger had time to tell
the dispatcher what was happening with the car before it crashed. This was
an event that took a very long time to transpire. These are very long
events, not momentary lapses.

Drive By Wire is a system that certainly can work as the driver would
expect -- the car speeds when the pedal is pressed, levels out if the pedal
is held at mid-scale, and slows if the pedal is released. We have jet
aircraft that use fly-by-wire, surely the system can be implemented reliably
in an automobile.

The issue isn't that the system may fail, the issue is the response of the
company that put the system into the car. That's the issue.

Toyota spent lots of money denying the problem existed when it appears now
that they knew all along that it was a real problem. In a perfect world, the
system would never fail, but in the real world the system has failed many
times.





From: Jeff Strickland on

"jim beam" <me(a)privacy.net> wrote in message
news:uqOdnfdrX4d5Lg_WnZ2dnUVZ_qKdnZ2d(a)speakeasy.net...
>
>> Fail safe and redundancy should be part of any
>> throttle system, but even that can fail, as have the simplest of
>> mechanical systems.
>
> indeed. statistically, mechanical throttles are much more unreliable.


STATISTICALLY?

I'd like to see any statistic you have ...

The facts are that save a few notable examples -- Audi -- there have been
virtually no known cases of unintended acceleration that involved vehicles
on the highway. The only known instances of wrong-pedal acceleration involve
vehicles in parking lots.

To be sure, there are exceptions -- the guy that drove his Buick through the
Farmer's Market in Los Angeles and ran over several people -- but the
exception is just that. An exception.

Statistically, the exception is not noteworthy. There is no statistic that
says mechanical throttles less reliable. Indeed, statistically speaking,
electronic throttle controls (fly-by-wire gas pedals) haven't been in use
long enough to be a statistically large enough sample to compare against the
decades of mechanical throttle mechanisms that have gone into millions upon
millions of vehicles.






From: Jeff Strickland on

"jim beam" <me(a)privacy.net> wrote in message
news:uqOdnfZrX4eWKQ_WnZ2dnUVZ_qIAAAAA(a)speakeasy.net...
>>
>> When or why one might press or release the pedal has no bearing on the
>> discussion. The only thing that matters is the expecation that the car
>> goes
>> faster when the pedal is pressed and stops going faster when the pedal is
>> held at a mid-point, and slows when the pedal is released.
>>
>> When the throttle control system does those things, then it is doing its
>> job.
>
> why is it that people that don't know what they're talking about insist on
> having "opinions"?
>

I was wondering the same thing about you ...

You postulate stupid ideas that have absolutely no basis in reality.

The gas pedal has one job, make the car go. When the pedal is pressed the
car goes, when the pedal is not pressed the car stops going. It is not
expected to do anything more, or anything less. This function has taken
place for more than 100 years, and has never been a problem like what we
have today.