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.

Reply to
mark digital©
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According to this article,

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GM is discontinuing the CVT altogether.

Reply to
Ray O

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.

Reply to
Bill Tuthill

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.

Reply to
Andrew Stephenson

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.

Reply to
Bill Tuthill

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.

Reply to
Andrew Stephenson

Read the "Technology" section of this Toyota website:

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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:
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Reply to
NeoPhyte_Rep

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.

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!

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

Reply to
Bill Tuthill

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

Reply to
Andrew Stephenson

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

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

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Reply to
Bill Tuthill

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