Joe wrote:

> "maxpower" > wrote in message
> ...
>
>>"James C. Reeves" > wrote in message
...
>>
>>>"Steve" > wrote in message
...
>>>
>>>>I firmly believe that virtually 100% of the cases of "unintended
>>>>acceleration" in cars made prior to about 2001 were because of driver
>>>>error. There's simply NO way that an engine with a mechanical throttle
>>>>linkage can accelerate unless the return spring breaks, and it doesn't
>>
>>"go
>>
>>>>back to normal" immediately thereafter- it stays broken.
>>>>
>>>>Howver, in recent years more cars are being built with "throttle by
>>
>>wire"
>>
>>>>in which a computer-controlled servo moves the throttle blades, not a
>>>>direct mechanical linkage to the accelerator pedal. I know that the
>>>>systems and software go through tremendous testing, but I no longer
>>>>feel
>>>>confident in saying that it "cannot happen" anymore.
>>>>
>>>
>>>Which begs the question...why make a very simple and reliable system more
>>>complicated (with all the associated problems that more complicated
>>
>>systems
>>
>>>have)?
>>>
>>>ITS ALL ABOUT MONEY, no cables, brackets, save on money and supposed to
>>>be
>>
>>a faster response for acceleration
>>
>
> I doubt that, I think it's for slower acceleration. If they put "throttle
> response" in the hands of the computer, it can respond whenever it wants to.
> At least that's the feeling I get when I drive one. If the computer decides
> to downshift, it can wait before it actually opens the throttle.
>
> This has got to be much easier for engine management. Cheaper? No. That's
> just stupid, to think a motor-driven throttle is cheaper than a cable.


One motor-driven throttle that can be used on EVERY engine in EVERY car
made by the company is cheaper to produce than a different throttle
cable for every engine/chassis combination. Not case-by-case, but in
terms of mass production.

As far as slowing down acceleration- that's mostly (my guess) to control
emissions and boost fuel economy. The real software benefit of TBW is
that the computer can cut the throttle whenever the automatic
transmission shifts, which allows the transmissions to be built even
lighter and cheaper than they already are because now the computer can
guarantee that there's no such thing as a "wide open throttle upshift,"
which transmissions used to have to be able to handle.