Multitronic CVT question

[fysmd]

Sorry if a FAQ but I'm confused: does my Multitronic use a torque converter or some form of friction system?

I notice a big difference between my 2012 and previous 09 model. OK it has 7 more PS' but the drive feels MUCH better, especially during initial acceleration.

[5678]

I believe the Audi system works using the "cone and belt" based CVT system. Think something like mountain bike gears.

Good CVT explanation here: CVT - what the Continuously Variable Transmission is and how CVT works

[KAM]

Good old Wikipedia also has what seems, to me anyway, a credible description -
multitronic - Wikipedia, the free encyclopedia

[bmoster]

I think that Audi have been continually improving the Multitronic. The latest one in the A6 is supposed to be a lot better than earlier ones which were criticised for a sort of "power boat" effect i.e.when you set off the engine jumped to high revs and stayed there. The latest one does not do that and is much more refined.

[5678]

Mine tends to jump to around 2500-3000 and then gradually increase from there.

[fysmd]

Thanks for all the feedback, I understand how the gearbox itself works but wondered how the "clutch" works. It doesn't feel like a torque converter and I think I have read a reference here somewhere (can't find now) that its some form of friction based clutch.
If it's not a torque converter how / why does it creep? And wouldn't it be a bad thing in lots of slow city traffic?

Also, in terms of fuel economy, sitting stationary in gear reduces rpm by a few 100. popping it into neutral returns engine to slightly higher speed, is this better than sitting on a brake?

[Whippy53]

As with any automatic, it's OK to sit in gear for a short while but always better to knock it out of drive if stationary for more than 30 sec or so as eventually you can promote wear within the clutch drive. The creep factor has been engineered in to make the system more acceptable.

[jbanfie]

It's a clutch!!!

From

Audi multitronic
"Audi instead uses an oil-cooled multi-plate clutch which not only avoids the
typical transmission losses of the torque converter, but also implements a
variety of starting strategies. These are selected by the electronic control
circuitry in accordance with the driver's preferences, as detected from how the
accelerator pedal is being used. The electronic-control multi-plate clutch
moreover offers the convenience feature of constant creep behaviour. "

[BrianWM]

I suspect it's basically the same as the clutch on the s-tronic, just a differenct gearbox connected to it. Mines the s-tronic and although I'd prefer a torque converter in stop start traffic, the clutch doesn't do too bad. I have a bit of an issue with reversing up hill though ! (see other thread)

I'd like to know if the drag on the clutch, which is essential for the feel of the car, still happens with your foot firmly on the brake or when the hill hold is in operation. It'd be a pointless waste of energy, clutch lining and you'd think the software would know it isn't needed.

[fysmd]

... The creep factor has been engineered in to make the system more acceptable.

What does this mean, the system wouldn't creep like a classic auto so has had magic applied to make it look / feel like a classic auto?
Geek in me has to ask: how?