How does Audi's multitronic transmission work?

Audi is advertising multitronic transmission, saying that there are no gears, so there is no shifting. Wouldn’t you still have to shift into drive, reverse, park?

Audi’s Multitronic transmission - How does it work?

Darn it astro,same article I was gonna link:p
Yes,**flowers **, you still use F, R and P.

Great link! I was dissapointed by the modest increase in fuel efficiency though. I thought that a cvt would have been more of an improvement.

Maybe someone can help me understand this. I understand that there is a chain drive and that it uses friction force alone. That’s about as far as I got.

“The Variator has two tapered disc pairs - a set of primary drive pulleys and a set of secondary driven pulleys. A special chain runs between the two pulleys to transmit power to the drive wheels.”

Which 2 pulleys? Do they mean between the 2 sets of pulleys?
Can anyone tell which are the drive and which are the driven from the illustration?

Yes. By moving the two half-pulleys closer or farther from each other, each set acts like a resizable gear.

The cross-section looks like this: > <

The chain rides between the two halves. As the halves move closer together, the chain is forced to ride on the outer rim, as if it were a larger gear. When the halves move apart, the chain slides down so it’s riding on the inside, like a smaller gear.

I believe the larger set is connected to the wheels; the other way around, it’d be a huge overdrive ratio.

Thanks. Very helpful. I think I pretty much get it now.

Since this question is pretty much answered, can I ask a few other questions?

There have been some strange transmissions in the past which I do not understand. The manual for my '74 Beetle gave instructions for a semi-automatic transmission (which I did not have) which had a standard gearshift, but no clutch. Apparently, the driver would just let off the gas, depress a button on the shifter, select the gear, and push the go-pedal. How did this work?

And there was (if I recall correctly) a Packard, which had some sort of single-gear transmission which I don’t understand at all. I’m pretty curious about that as well. Anyone know anything at all about this one?

Nothing useful to add to this thread, but I do have yet another question:

Are these infinitely variable gearing systems still used on bicycles?

I remember seeing one in a cycling book in the early 80s. I can’t remember if the rear gears were conventional, but at the front, the chain ran over a series of little cogwheels arranged in a radial fashion around a disk where the front sprocket normally would be. The small cogs could travel in and out, using a spring mechanism, in a groove along the disk. It was, IIRC, operated manually by a regular lever and cable set-up.