| Author |
Message |
Nomen Nescio
Guest
|
 Posted:
Mon Dec 05, 2005 12:30 am Post subject:
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.
|
|
| Back to top |
|
 |
Shoe Salesman
Guest
|
| Posted:
Mon Dec 05, 2005 7:28 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
HERE WE GO AGAIN>>>>>> :(
"Nomen Nescio" <nobody@dizum.com> wrote in message
news:a9f8d617de1af8b6149feea83518d86b@dizum.com...
| Quote: | 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.
|
|
|
| Back to top |
|
|
Spam Hater
Guest
|
| Posted:
Mon Dec 05, 2005 9:15 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
In article <a9f8d617de1af8b6149feea83518d86b@dizum.com>,
Nomen Nescio <nobody@dizum.com> wrote:
| Quote: | 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.
|
|
| Back to top |
|
|
Al Bundy
Guest
|
| Posted:
Mon Dec 05, 2005 8:54 pm Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
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. |
|
| Back to top |
|
|
Eugene Nine
Guest
|
| Posted:
Tue Dec 06, 2005 6:20 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
Nomen Nescio wrote:
| Quote: | 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. |
|
| Back to top |
|
|
Joe Pfeiffer
Guest
|
| Posted:
Tue Dec 06, 2005 7:17 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
| Quote: | 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 |
|
| Back to top |
|
|
Bill Putney
Guest
|
| Posted:
Tue Dec 06, 2005 9:12 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
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') |
|
| Back to top |
|
|
Marc
Guest
|
| Posted:
Tue Dec 06, 2005 9:14 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
(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...
| Quote: | 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') |
|
|
| Back to top |
|
|
joe schmoe
Guest
|
| Posted:
Tue Dec 06, 2005 4:33 pm Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
On Mon, 05 Dec 2005 22:12:13 -0500, Bill Putney <bptn@kinez.net>
wrote:
| Quote: | 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.com/int/pressrelases.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. |
|
| Back to top |
|
|
Bill Putney
Guest
|
| Posted:
Tue Dec 06, 2005 11:40 pm Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
Marc wrote:
| Quote: | (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') |
|
| Back to top |
|
|
Marc
Guest
|
| Posted:
Wed Dec 07, 2005 5:59 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
Check out the latest transmissions, Bill. Look at how smoothly
computer-controlled automatic-shifting manual transmissions engage the
clutch and shift. I've no doubt an automatic transmission's torque
converter can be similarly controlled to engage and disengage, even more
easily since it's got the benefit of hydraulics to dampen help smooth things
out.
We may never see such torque converters, though, if the automatic-shifting
manual transmissions start replacing traditional automatics entirely.
For example, check out the VW group's six-speed direct-shift gearbox in the
Audi A3, a hatchback sedan priced only in the $25,000-$30,000 range. This
transmission is also available in the VW Golf. You can click off
lightning-fast upshifts and downshifts with the F1-style paddles or let it
shift itself with smoothness that easily rivals an automatic.
Google "DSG" and you can read up on it. I found this quote: --"The
transmission also has a system that apes Formula 1 'launch control'. Keep
your left foot on the brake. Select 'Sport' mode on the transmission
quadrant. Switch off the ESP. Floor the throttle. The engine then revs to
3,200rpm, where it develops peak torque, but no more. All you have to do is
slide your left foot off the brake but keep the right fully planted and you
take off, redlining through all six gears if you have the space. But because
you have set off at comparatively low revs and because of the way the twin
wet clutches work, you could if you wanted to do this repeatedly without
straining or overheating the box."--
I bet that once you get a direct-shift gearbox you won't want any other
transmission -- why bother with a torque converter at all? Fortunately
we're seeing transmissions like these more and more due to the power and
efficiency benefits.
"Bill Putney" <bptn@kinez.net> wrote in message
news:dn4idf$vl4$1@news.isdn.net...
| Quote: | Marc wrote:
(1) would be easy enough -- light throttle application would give a
properly
designed torque converter (i.e., one designed for releasing into a
free-wheeling mode while stopped and for re-engaging smoothly) ample
opportunity to gently re-engage with nothing more than a light shift
sensation such as any other upshift sensation might create.
(2) would be easy with drive-by-wire. Giving the computer full control
of
the vehicle lets the manufacturer design in behaviors they couldn't
otherwise. With the computer in full control of the throttle, the
driver
flooring it from a standstill would cause the torque converter to
re-engage
as quickly as it is designed to re-engage -- at whatever throttle
opening
the computer deems reasonable -- followed by the computer ordering a
rapid
opening of the throttle to fully open. With drive-by-wire, competent
programming and a competent transmission, this could be done amazingly
fast.
Your solution for (2) would either give a slamming effect or cause a
perceptable delay in response. With the present system power train
slack already taken up and engaged, acceleration could start immediately
with no slam of engagement - quicker than the drive-by-wire. Maybe it
could be made "quick enough", but never quite as quick.
Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x') |
|
|
| Back to top |
|
|
Ted Mittelstaedt
Guest
|
| Posted:
Wed Dec 07, 2005 9:14 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
"Marc" <marcuscl@b.n> wrote in message
news:syplf.19657$wi2.6694@bignews1.bellsouth.net...
| Quote: | Check out the latest transmissions, Bill. Look at how smoothly
computer-controlled automatic-shifting manual transmissions engage the
clutch and shift. I've no doubt an automatic transmission's torque
converter can be similarly controlled to engage and disengage, even more
easily since it's got the benefit of hydraulics to dampen help smooth
things
out.
We may never see such torque converters, though, if the automatic-shifting
manual transmissions start replacing traditional automatics entirely.
For example, check out the VW group's six-speed direct-shift gearbox in
the
Audi A3, a hatchback sedan priced only in the $25,000-$30,000 range. This
transmission is also available in the VW Golf. You can click off
lightning-fast upshifts and downshifts with the F1-style paddles or let it
shift itself with smoothness that easily rivals an automatic.
Google "DSG" and you can read up on it. I found this quote: --"The
transmission also has a system that apes Formula 1 'launch control'. Keep
your left foot on the brake. Select 'Sport' mode on the transmission
quadrant. Switch off the ESP. Floor the throttle. The engine then revs to
3,200rpm, where it develops peak torque, but no more. All you have to do
is
slide your left foot off the brake but keep the right fully planted and
you
take off, redlining through all six gears if you have the space. But
because
you have set off at comparatively low revs and because of the way the twin
wet clutches work, you could if you wanted to do this repeatedly without
straining or overheating the box."--
I bet that once you get a direct-shift gearbox you won't want any other
transmission
|
Your wrong there.
| Quote: | -- why bother with a torque converter at all?
|
Agreed. Why, when a properly designed dry clutch and a fully manual
transmission is
superior in every way.
Of course, it takes skillful drivers to operate, which the majority of the
American public aren't - which is why we get stuck with the mess of
mechanical misconceptions like your VW transmission.
| Quote: | Fortunately
we're seeing transmissions like these more and more due to the power and
efficiency benefits.
|
Fortunate if your a trans repair shop. For everyone else, the slight
savings in mileage will be offset by the cost to repair the things
when they break down, which will be often once they go past the
woefully short warranty period.
Ted |
|
| Back to top |
|
|
Bill Putney
Guest
|
| Posted:
Wed Dec 07, 2005 5:13 pm Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
Marc wrote:
| Quote: | Check out the latest transmissions, Bill. Look at how smoothly
computer-controlled automatic-shifting manual transmissions engage the
clutch and shift. I've no doubt an automatic transmission's torque
converter can be similarly controlled to engage and disengage, even more
easily since it's got the benefit of hydraulics to dampen help smooth things
out.
We may never see such torque converters, though, if the automatic-shifting
manual transmissions start replacing traditional automatics entirely.
For example, check out the VW group's six-speed direct-shift gearbox in the
Audi A3, a hatchback sedan priced only in the $25,000-$30,000 range. This
transmission is also available in the VW Golf. You can click off
lightning-fast upshifts and downshifts with the F1-style paddles or let it
shift itself with smoothness that easily rivals an automatic.
Google "DSG" and you can read up on it. I found this quote: --"The
transmission also has a system that apes Formula 1 'launch control'. Keep
your left foot on the brake. Select 'Sport' mode on the transmission
quadrant. Switch off the ESP. Floor the throttle. The engine then revs to
3,200rpm, where it develops peak torque, but no more. All you have to do is
slide your left foot off the brake but keep the right fully planted and you
take off, redlining through all six gears if you have the space. But because
you have set off at comparatively low revs and because of the way the twin
wet clutches work, you could if you wanted to do this repeatedly without
straining or overheating the box."--
I bet that once you get a direct-shift gearbox you won't want any other
transmission -- why bother with a torque converter at all? Fortunately
we're seeing transmissions like these more and more due to the power and
efficiency benefits.
|
Thanks for that information - I wasn't aware of the TC-less "automatic"
transmissions.
Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x') |
|
| Back to top |
|
|
Larry Crites
Guest
|
| Posted:
Thu Dec 08, 2005 12:17 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
GM doesn't know anything.
Larry
Behold Beware Believe
"Eugene Nine" <no@spam.com> wrote in message
news:aJGdnekHMfRXRAneRVn-iw@wideopenwest.com...
|
| <snip>
|
| 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.
| |
|
| Back to top |
|
|
Marc
Guest
|
| Posted:
Thu Dec 08, 2005 4:28 am Post subject:
Re: Automatic Transmission Drag Kills Stop and Go Gas Mileag |
|
|
Do you have the doom-and-gloom response about other technologies like
antilock brake systems, traction control, active suspension, etc.? I
imagine there were people having that reaction about disc brakes once upon a
time. For my part, I'll reserve judgement on their reliability until we see
statistics.
What *does* bother me a bit about all these new technologies is that they
require greater and greater control of the vehicle by the computer. How
long will it be before you start receiving traffic tickets in the mail
because your own car's computer notified the police department that you were
doing 78 in a 70 zone? Or how long before your car's computer refuses to
allow the vehicle to exceed the posted speed limit? Or how long before
police departments start using GPS data to send out speeding tickets, or
before the insurance companies increase your rate because GPS data indicates
you regularly exceed speed limits? That could all just be paranoia but it's
all easily conceivable given the revenue it represents for governments and
insurance companies and so forth.
Manual transmissions are great but they also require constant management by
the driver, which is why most people don't buy them. I love manual
transmissions but the two cars we own are automatics, partly because they're
both Durangos, but also because they're daily commuter vehicles and
passenger carriers where manual transmissions get a bit tedious. If I could
afford a third car as a fun/weekends kinda vehicle I'd get a manual.
"Ted Mittelstaedt" <tedm@toybox.placo.com> wrote in message
news:newscache$5w44ri$olk$1@news.ipinc.net...
| Quote: |
"Marc" <marcuscl@b.n> wrote in message
news:syplf.19657$wi2.6694@bignews1.bellsouth.net...
Check out the latest transmissions, Bill. Look at how smoothly
computer-controlled automatic-shifting manual transmissions engage the
clutch and shift. I've no doubt an automatic transmission's torque
converter can be similarly controlled to engage and disengage, even more
easily since it's got the benefit of hydraulics to dampen help smooth
things
out.
We may never see such torque converters, though, if the
automatic-shifting
manual transmissions start replacing traditional automatics entirely.
For example, check out the VW group's six-speed direct-shift gearbox in
the
Audi A3, a hatchback sedan priced only in the $25,000-$30,000 range.
This
transmission is also available in the VW Golf. You can click off
lightning-fast upshifts and downshifts with the F1-style paddles or let
it
shift itself with smoothness that easily rivals an automatic.
Google "DSG" and you can read up on it. I found this quote: --"The
transmission also has a system that apes Formula 1 'launch control'.
Keep
your left foot on the brake. Select 'Sport' mode on the transmission
quadrant. Switch off the ESP. Floor the throttle. The engine then revs
to
3,200rpm, where it develops peak torque, but no more. All you have to do
is
slide your left foot off the brake but keep the right fully planted and
you
take off, redlining through all six gears if you have the space. But
because
you have set off at comparatively low revs and because of the way the
twin
wet clutches work, you could if you wanted to do this repeatedly without
straining or overheating the box."--
I bet that once you get a direct-shift gearbox you won't want any other
transmission
Your wrong there.
-- why bother with a torque converter at all?
Agreed. Why, when a properly designed dry clutch and a fully manual
transmission is
superior in every way.
Of course, it takes skillful drivers to operate, which the majority of the
American public aren't - which is why we get stuck with the mess of
mechanical misconceptions like your VW transmission.
Fortunately
we're seeing transmissions like these more and more due to the power and
efficiency benefits.
Fortunate if your a trans repair shop. For everyone else, the slight
savings in mileage will be offset by the cost to repair the things
when they break down, which will be often once they go past the
woefully short warranty period.
Ted
|
|
|
| Back to top |
|
|
|
|
|
|
FAQ
Memberlist
Register
Profile
Log in to check your private messages
Log in