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Old 12-04-2005, 17:01   #1 (permalink)
Nomen Nescio
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Automatic Transmission Drag Kills Stop and Go Gas Mileage

On virtually every automatic transmission car, while in stop and go
driving, it is necessary for the driver to ride the brake to keep the car
stationary or at speeds lower than approximately 10 mph.

This is because the transmission couples at idle speeds instead of going
into a neutral condition. This self propulsion occurs whenever the drive
range is selected, even though no pressure is applied to the gas pedal.

When the engine has to idle against this braking drag, the engine has to
work harder than if it were a no load idle. A byproduct of this
undesirable drag is increased fuel consumption as well as increased engine
and transmission heat. It might even cause a few accidents when the car
pulls into a slow car in front if the driver day dreams or his braking foot
gets too tired.

So why don't the automakers develop an automatic transmission that does not
pull the car when the engine idles and there is no pressure on the gas
pedal? I think its possible to do this because Toyota had a CVT
transmission that was perfect until testers complained it was too different
from regular hydraulic transmissions. So, Toyota made the CVT pull just
like all the others do. That proves Toyota is just as stupid as anybody
else in the business.

This is No. 27 of 1001 improvements desperately needed.

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Old 12-04-2005, 18:01   #2 (permalink)
Shoe Salesman
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

HERE WE GO AGAIN>>>>>> :(
"Nomen Nescio" <nobody@dizum.com> wrote in message
news:a9f8d617de1af8b6149feea83518d86b@dizum.com...
> On virtually every automatic transmission car, while in stop and go
> driving, it is necessary for the driver to ride the brake to keep the car
> stationary or at speeds lower than approximately 10 mph.
>
> This is because the transmission couples at idle speeds instead of going
> into a neutral condition. This self propulsion occurs whenever the drive
> range is selected, even though no pressure is applied to the gas pedal.
>
> When the engine has to idle against this braking drag, the engine has to
> work harder than if it were a no load idle. A byproduct of this
> undesirable drag is increased fuel consumption as well as increased engine
> and transmission heat. It might even cause a few accidents when the car
> pulls into a slow car in front if the driver day dreams or his braking
> foot
> gets too tired.
>
> So why don't the automakers develop an automatic transmission that does
> not
> pull the car when the engine idles and there is no pressure on the gas
> pedal? I think its possible to do this because Toyota had a CVT
> transmission that was perfect until testers complained it was too
> different
> from regular hydraulic transmissions. So, Toyota made the CVT pull just
> like all the others do. That proves Toyota is just as stupid as anybody
> else in the business.
>
> This is No. 27 of 1001 improvements desperately needed.
>



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Old 12-04-2005, 23:01   #3 (permalink)
Spam Hater
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

In article <a9f8d617de1af8b6149feea83518d86b@dizum.com>,
Nomen Nescio <nobody@dizum.com> wrote:

> On virtually every automatic transmission car, while in stop and go
> driving, it is necessary for the driver to ride the brake to keep the car
> stationary or at speeds lower than approximately 10 mph.


Smarter drivers than you shift into neutral on long stops.
Your foot should still be on the brakes to keep you at the same location.
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Old 12-05-2005, 07:01   #4 (permalink)
Al Bundy
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

Like my father used to say, "Ideas are a dime a dozen."
Nomen's "ideas" are often born from ignorance of the details and
frustration in not being able to execute ideas in his personal life.
That's just my opinion.

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Old 12-05-2005, 17:01   #5 (permalink)
Eugene Nine
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

Nomen Nescio wrote:

> On virtually every automatic transmission car, while in stop and go
> driving, it is necessary for the driver to ride the brake to keep the car
> stationary or at speeds lower than approximately 10 mph.
>
> This is because the transmission couples at idle speeds instead of going
> into a neutral condition. This self propulsion occurs whenever the drive
> range is selected, even though no pressure is applied to the gas pedal.
>
> When the engine has to idle against this braking drag, the engine has to
> work harder than if it were a no load idle. A byproduct of this
> undesirable drag is increased fuel consumption as well as increased engine
> and transmission heat. It might even cause a few accidents when the car
> pulls into a slow car in front if the driver day dreams or his braking
> foot gets too tired.
>
> So why don't the automakers develop an automatic transmission that does
> not pull the car when the engine idles and there is no pressure on the gas
> pedal? I think its possible to do this because Toyota had a CVT
> transmission that was perfect until testers complained it was too
> different
> from regular hydraulic transmissions. So, Toyota made the CVT pull just
> like all the others do. That proves Toyota is just as stupid as anybody
> else in the business.
>
> This is No. 27 of 1001 improvements desperately needed.

Thats why new cars in a couple years will shut the engine off when your
stopped. The Hybrid Silverado was a testbed for this and it will be
incorporated into most models soon.

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Old 12-05-2005, 19:01   #6 (permalink)
Joe Pfeiffer
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

> Nomen Nescio wrote:
> >
> > This is No. 27 of 1001 improvements desperately needed.


Oh God no.
--
Joseph J. Pfeiffer, Jr., Ph.D. Phone -- (505) 646-1605
Department of Computer Science FAX -- (505) 646-1002
New Mexico State University http://www.cs.nmsu.edu/~pfeiffer
skype: jjpfeifferjr
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Old 12-05-2005, 21:01   #7 (permalink)
Bill Putney
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

Nomen Nescio wrote:


Sorry for feeding the troll, but I challenge anyone to design a tranny
control algorithm for re-engagement following the
complete-dropout-at-idle that can adequately handle *both* of the
following to the satisfaction of the consumer:
(1) A smooth start with light application of throttle for gradual old
lady takeoff from stopped,
*AND*
(2) A sudden pedal-to-the-floor start without effectively simulating a
high rev. neutral drop.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')
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Old 12-05-2005, 21:01   #8 (permalink)
Marc
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

(1) would be easy enough -- light throttle application would give a properly
designed torque converter (i.e., one designed for releasing into a
free-wheeling mode while stopped and for re-engaging smoothly) ample
opportunity to gently re-engage with nothing more than a light shift
sensation such as any other upshift sensation might create.

(2) would be easy with drive-by-wire. Giving the computer full control of
the vehicle lets the manufacturer design in behaviors they couldn't
otherwise. With the computer in full control of the throttle, the driver
flooring it from a standstill would cause the torque converter to re-engage
as quickly as it is designed to re-engage -- at whatever throttle opening
the computer deems reasonable -- followed by the computer ordering a rapid
opening of the throttle to fully open. With drive-by-wire, competent
programming and a competent transmission, this could be done amazingly fast.

I guess he had a more workable idea than you would have guessed...

"Bill Putney" <bptn@kinez.net> wrote in message
news:dn2vic$1lq$1@news.isdn.net...
> Nomen Nescio wrote:
>
>
> Sorry for feeding the troll, but I challenge anyone to design a tranny
> control algorithm for re-engagement following the
> complete-dropout-at-idle that can adequately handle *both* of the
> following to the satisfaction of the consumer:
> (1) A smooth start with light application of throttle for gradual old
> lady takeoff from stopped,
> *AND*
> (2) A sudden pedal-to-the-floor start without effectively simulating a
> high rev. neutral drop.
>
> Bill Putney
> (To reply by e-mail, replace the last letter of the alphabet in my
> address with the letter 'x')



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Old 12-06-2005, 03:01   #9 (permalink)
joe schmoe
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

On Mon, 05 Dec 2005 22:12:13 -0500, Bill Putney <bptn@kinez.net>
wrote:

>Nomen Nescio wrote:
>
>
>Sorry for feeding the troll, but I challenge anyone to design a tranny
>control algorithm for re-engagement following the
>complete-dropout-at-idle that can adequately handle *both* of the
>following to the satisfaction of the consumer:
>(1) A smooth start with light application of throttle for gradual old
>lady takeoff from stopped,
>*AND*
>(2) A sudden pedal-to-the-floor start without effectively simulating a
>high rev. neutral drop.
>
>Bill Putney
>(To reply by e-mail, replace the last letter of the alphabet in my
>address with the letter 'x')



Sorry, I believe that Ferrari VW, and Porsche already have this taken
care of (twin clutch manual/auto hybrids). I figure that if it's good
enough for a Porsche it might be good enough for a Taurus/Cavalier.

http://www.just-auto.com/features_detail.asp?art=1171
http://www.transmission-symposium.co...essrelases.htm

But if Nomen Nescio has a suggestion, I'm sure that it'll be better
than this. Perhaps I'm reading yesterday's news.
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Old 12-06-2005, 11:01   #10 (permalink)
Bill Putney
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Re: Automatic Transmission Drag Kills Stop and Go Gas Mileage

Marc wrote:

> (1) would be easy enough -- light throttle application would give a properly
> designed torque converter (i.e., one designed for releasing into a
> free-wheeling mode while stopped and for re-engaging smoothly) ample
> opportunity to gently re-engage with nothing more than a light shift
> sensation such as any other upshift sensation might create.
>
> (2) would be easy with drive-by-wire. Giving the computer full control of
> the vehicle lets the manufacturer design in behaviors they couldn't
> otherwise. With the computer in full control of the throttle, the driver
> flooring it from a standstill would cause the torque converter to re-engage
> as quickly as it is designed to re-engage -- at whatever throttle opening
> the computer deems reasonable -- followed by the computer ordering a rapid
> opening of the throttle to fully open. With drive-by-wire, competent
> programming and a competent transmission, this could be done amazingly fast.


Your solution for (2) would either give a slamming effect or cause a
perceptable delay in response. With the present system power train
slack already taken up and engaged, acceleration could start immediately
with no slam of engagement - quicker than the drive-by-wire. Maybe it
could be made "quick enough", but never quite as quick.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')
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