Automatic gear type and hybrid CVT question

I was reading a hands-on review of the Saturn Vue hybrid and one thing about
the drive train seemed odd. This vehicle uses a typical gear type
transmission.

My eldest son asked if I would gather information about this vehicle and
also the Prius. I know his situation quite well; his normal daily mileage
has just about quadrupled. He's held on to his Chevy SUV as long as he can
but the repairs are becoming more frequent and costly for him. His mechanics
are almost pleading with him to let go. Last I heard it's pushing 230,000
miles.

I don't know if the Saturn's list price was kept low by not using a more
efficient CVT. The CVT is statistically less of a headache but maybe, for
some user reason, it's not plausible. Not sure and that's where I need some
advice from knowledgeable people here.

"mark_digital©" <976-XXX@comcastnot.com> wrote in message
news:x-WdnRpwMaab6DbYnZ2dnUVZ_t-mnZ2d@comcast.com...[color=blue]
>I was reading a hands-on review of the Saturn Vue hybrid and one thing
>about the drive train seemed odd. This vehicle uses a typical gear type
>transmission.
>
> My eldest son asked if I would gather information about this vehicle and
> also the Prius. I know his situation quite well; his normal daily mileage
> has just about quadrupled. He's held on to his Chevy SUV as long as he can
> but the repairs are becoming more frequent and costly for him. His
> mechanics are almost pleading with him to let go. Last I heard it's
> pushing 230,000 miles.
>
> I don't know if the Saturn's list price was kept low by not using a more
> efficient CVT. The CVT is statistically less of a headache but maybe, for
> some user reason, it's not plausible. Not sure and that's where I need
> some advice from knowledgeable people here.[/color]

According to this article,
[url]http://car-reviews.automobile.com/news/general-motors-to-kill-continually-variable-transmission/166/[/url]
GM is discontinuing the CVT altogether.
--

Ray O
(correct punctuation to reply)

"mark_digital©" <976-XXX@comcastnot.com> wrote:[color=blue]
>
> I don't know if the Saturn's list price was kept low by not using a more
> efficient CVT. The CVT is statistically less of a headache but maybe, for
> some user reason, it's not plausible. Not sure and that's where I need some
> advice from knowledgeable people here. [/color]

The CVT in the Ford Freestyle is rated "less reliable than average"
by Consumer Reports, although I can't tell you why.

However CVT works well in railroad diesel engines.

In article <45abff89@news.meer.net> [email]ccreekin@yahoo.com[/email] "Bill
Tuthill" writes:
[color=blue]
> [...]
>
> However CVT works well in railroad diesel engines.[/color]

IIRC, Daf at one time made a Jeep-like vehicle for the Dutch army
which used their signature "two cones and a steel belt" CVT. The
natural assumption is that _that_ design was pretty reliable too.
--
Andrew Stephenson

Andrew Stephenson <ames@deltrak.demon.co.uk> wrote:[color=blue][color=green]
>>
>> However CVT works well in railroad diesel engines.[/color]
>
> IIRC, Daf at one time made a Jeep-like vehicle for the Dutch army
> which used their signature "two cones and a steel belt" CVT. The
> natural assumption is that _that_ design was pretty reliable too.[/color]

Do you ever get the feeling that the Prius transmission is just a
regular automatic tranny, not a CVT? I do, especially going up hills.

In article <45ac37ff@news.meer.net> [email]ccreekin@yahoo.com[/email] "Bill Tuthill" writes:
[color=blue]
> Andrew Stephenson <ames@deltrak.demon.co.uk> wrote:[color=green][color=darkred]
> >>
> >> However CVT works well in railroad diesel engines.[/color]
> >
> > IIRC, Daf at one time made a Jeep-like vehicle for the Dutch army
> > which used their signature "two cones and a steel belt" CVT. The
> > natural assumption is that _that_ design was pretty reliable too.[/color]
>
> Do you ever get the feeling that the Prius transmission is just a
> regular automatic tranny, not a CVT? I do, especially going up hills.[/color]

Yes and no. It seems to adjust at least as well. Its big extra
is there's none of that pause-then-surge as you floor the pedal:
it just applies more power... Thinking on it, the Prius' CVT is
too smooth to be mistaken for a regular transmission. The sound
effects are definitely different.
--
Andrew Stephenson

Andrew Stephenson wrote:[color=blue]
> In article <45ac37ff@news.meer.net> [email]ccreekin@yahoo.com[/email] "Bill Tuthill" writes:
>[color=green]
>> Andrew Stephenson <ames@deltrak.demon.co.uk> wrote:[color=darkred]
>>>> However CVT works well in railroad diesel engines.
>>> IIRC, Daf at one time made a Jeep-like vehicle for the Dutch army
>>> which used their signature "two cones and a steel belt" CVT. The
>>> natural assumption is that _that_ design was pretty reliable too.[/color]
>> Do you ever get the feeling that the Prius transmission is just a
>> regular automatic tranny, not a CVT? I do, especially going up hills.[/color]
>
> Yes and no. It seems to adjust at least as well. Its big extra
> is there's none of that pause-then-surge as you floor the pedal:
> it just applies more power... Thinking on it, the Prius' CVT is
> too smooth to be mistaken for a regular transmission. The sound
> effects are definitely different.[/color]

Read the "Technology" section of this Toyota website:
[url]http://www.hybridsynergydrive.com/en/top.html[/url]
especially:
[url]http://www.hybridsynergydrive.com/en/power_split_device.html[/url]
There is nothing to engage or disengage. The gears are always in
contact. A motor-generator smoothly controls how much gasoline power
and electric power is sent to the drive wheels.

This might also help you understand:
[url]http://www.cleangreencar.co.nz/page/prius-technical-info[/url]

NeoPhyte_Rep <abuse@127.0.0.1> wrote:[color=blue]
>
> Read the "Technology" section of this Toyota website:
> [url]http://www.hybridsynergydrive.com/en/top.html[/url]
> especially:
> [url]http://www.hybridsynergydrive.com/en/power_split_device.html[/url][/color]

What's odd about that diagram is that it shows the "generator"
separate from "electric motor". I thought they were one and the same:
the generator is just the motor operating in "reverse" (that is,
with mechanical input to generate electricity, instead of with
electrical input to generate torque). But apparently only sometimes.
Furthermore, it appears there are multiple electrical engines.
[color=blue]
> There is nothing to engage or disengage. The gears are always in
> contact. A motor-generator smoothly controls how much gasoline power
> and electric power is sent to the drive wheels.[/color]

What I don't understand is how the gasoline motor, which I've been told
operates at constant RPM, supplies power at different vehicle speeds.
However according to petrol_engine.html at the op. cit. website, RPM is
not necessarily constant.

Seems like I had a lot of misconceptions about hybrid synergy drive!
[color=blue]
> This might also help you understand:
> [url]http://www.cleangreencar.co.nz/page/prius-technical-info[/url][/color]

That webpage shows two units that are both electric motor and generator.
Hmm... anyhow, thanks!

In article <45ad96fb@news.meer.net> [email]ccreekin@yahoo.com[/email] "Bill
Tuthill" writes:
[color=blue]
> What's odd about that diagram is that it shows the "generator"
> separate from "electric motor". I thought they were one and the same:
> the generator is just the motor operating in "reverse" (that is,
> with mechanical input to generate electricity, instead of with
> electrical input to generate torque). [...][/color]

Separate units, at least in the Mk2 Prius. Publicity material
doesn't help there, sometimes talking of them as the same unit.
--
Andrew Stephenson

Andrew Stephenson <ames@deltrak.demon.co.uk> wrote:[color=blue]
>
> Separate units, at least in the Mk2 Prius. Publicity material
> doesn't help there, sometimes talking of them as the same unit.[/color]

So it appears the op. cit. Toyota-sponsored marketing website
is less accurate than this apparently independent New Zealand website:

[url]http://www.cleangreencar.co.nz/page/prius-technical-info[/url]

As to how the Prius CVT (or ECVT) deals with variable speeds
on the gasoline motor, this is fairly informative:

[url]http://www.cleangreencar.co.nz/page/prius-transmission[/url]