What ever happened to CVT?

What happened to the CVT that was standard on the AWD 500, was drivers did not know how to drive them. Including those that one would suspect should know how, car mags test drivers.

The CVT was standard in the AWD 500 to make it a much better handling car when traction was less than ideal. The CVT which has an infinite gear range, was a no charge option on the FWD 500, that had a six speed double OD automatic as standard

A convention automatic starts in the lowest gear and up shifts depending on RPMs and throttle position. A CVT starts in the mid range of it "gearing" ratio, which is equivalent to around an eight speed automatic with triple OD. A CVT is by design trying is get to most efficient ratio in the shortest distance based on the terrain and throttle position. I E If one starts out going down a steep grade with very little throttle it will start in say six gear and quickly go to top range. If one starts out going up a steep grade with very little throttle it will start in say four range and stay there until one lets up on the throttle when they reach the speed desired. At that point it will select a higher gear at which the engine torque can maintain that speed.

The proper way to drive a CVT is rapidly floor the throttle to get up into the maximum torque range to make the "gear" cones move to drop to their lowest range to get the vehicle moving. As the vehicle picks up speed the cones will move to the higher gear range to take advantage of the HP needed to keep it moving on level ground. When one get to the speed they want one release the throttle to maintain that speed, at the most efficient ratio to do so.

In the real world drivers pressed the throttle part way, as they did with their four speed tranny and ended up starting in around the third "gear" range rather than first gear. Thus giving the impression the car was under powered when in fact if one was climbing a long grade holding the throttle were is was and letting the tranny change to a ratio that best used the torque to hold speed, rather than HP and a lower gear in a conventional tranny, one could 5 MPG or more better fuel mileage in hilly and mountainous parts of the country than the six speed convention tranny in a 500

mike

"You're wrong. It's essentially an "infinite speed" transmission.

Jeff"

I don't understand what you're getting at. The first link you provided doesn't list any articles, and the second link to the Toyota site reinforced what I was saying; that engine speed doesn't have any direct effect on vehicle speed. I don't see where you think I'm wrong. The PSD doesn't exist to find the best ratio between the crankshaft and wheels based on demand like in a CVT. The engine only supplements the primary electric motor, which is in a direct 1:1 drive with the wheels. At the bottom of that page there is even an asterisk that says "Only the r.p.m. of the electric motors is controlled in proportion to the vehicle speed."

Here is a great graphical representation of the PSD, infact almost identical to the one that Toyota uses in the Hybrid Synergy Drive classes they sent me to. You can see that the ring gear is fixed to the wheels, and changing engine RPM has no effect on wheel speed.

Of course.

Intelligent use of electrical power, including regenerative braking like what you describe, is a very nice bridge to get us over today's hurdles and into tomorrow's technology.

That's why the Prius brakes never get replaced.

That's right. It is a transmission, and it is stepless--that is to say, continuously variable.

That's why I always preface my comments about it by saying a "traditional" automatic trans or a "traditional" CVT.

The whole Power Split Device and design of the Hybrid Synergy Drive is pure genius. Every car should be like this. The Japanese have a history of copying and improving technology--well, this is one that they did on their own, and shame on General Motors for not focusing on technology enough to come up with this.

Yeah, it's a real cool little piece of technology. When I was sent to a Prius class a couple of years ago at one of Toyota's tech centers, we took one of the drivetrains apart. I was struck by how simple the whole thing is. I was expecting something complicated, and was shocked to find a couple of electric motors and a planetary gearset. No valves, valve body, lockup devices, or multiple gearsets of varying ratios. All the magic happens the software that controls the whole thing. By the way Elmo, you have the coolest name so far.

"Moon Goddess" ...

Moon Goddess - look at this site for an explanation of how the Prius works.

Interesting. What kind of MPG does it get?

"Moon Goddess" ...

Mine gets around 55 MPG tooling around west central NJ at this time of year. It does depend upon how I drive - if I am in a hurry it can drop to maybe 50 or so. In the winter it is in the high 40's as it runs the gas engine more to provide heat. Tomes

But don't you wind up paying for that savings with the extra cost of the car? Arent they around $45k?

And then the batteries must be super expensive too, and need to be replaced every 2 years?

My work involves a lot of deliveries ( city driving ) and idling time with the AC or heat running.

Um, no.

But then, a simple check anywhere on the net, or--God forbid--at your local Toyota dealer would have told you that.

Um, no.

I'll tell you what: I'll get a Prius, you get a whatever, we'll both do the same job in the same geographical territory, and we'll compare maintenance and repair receipts after 2 years.

We'll also compare brake pads and rotors. Prius, unused. Yours, replaced 4 times.

No, they aren't that expensive at all. I think a nice equipped Prius is somewhere in the low to mid 20s. And the whole battery replacement thing is crap. I've serviced some with well over 100k, with no charging issues at all. In my time with Toyota I've only had to replace a handful of main battery packs, all of which were covered under warranty. As far as your driving habits, city driving is where the economy really comes through. Stop and go traffic gives the Prius more opportunity to drive with the engine off (thus saving more fuel), and the most recent generation has an electric AC compressor, so the engine doesn't necessarily have to be running for AC operation. You should go by a dealer and drive one if you're in the market, they're really cool pieces of technology.

Thanks, this is really interesting, even shagnasty's comments, which I apparently deserved for being a little lazy to look it up myself. :)

Thanks.

We currently have a 93 Corolla wagon. Doesn't look like the Prius has much hatch space compared to that.

What's the hybrid equivalent?

Hey, with that Prius, how often do you change the oil on those? Same 3000 miles?

Seems like it might be less frequent because of the hybrid?

They're in the low to high (as in ~ 27) $20K's - depending on the pkg. that you get.

The battery's warranty is 8 - 10 years, depending on where you live. Plus, I haven't heard of them having any battery probs - either with the prior generation ('03) or the newer one ('04 - present).

The Prius loves city driving, re: MPG. When stopped or going *very* slowly, only the electric motor is running. Which is really cool because (besides not using gas), it's super-quiet then - with not even a quiet engine running.

Cathy

and idling time

Like I said, I do a lot of idling with the AC running to keep my partner cool in the summer, or the heat running in the winter.

This is interesting: