All Wheel Drive Encyclopedia
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quattro (English, Русский)

quattro is a registered trademark of Audi AG, a subsidiary of the German automotive concern, Volkswagen Group, used exclusively on Audi-branded automobiles which utilise four-wheel drive systems. This trademark does not indicate a specific type of a four-wheel drive system in use on the vehicle. Generally, quattro-branded Audi vehicles with transverse engine mounting have Haldex automatic all wheel drive and vehicles with longtitudial engine mounting are using Torsen full-time all wheel drive.

See quattro evolutions

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1-15 of 19 Comments
Derek
January 09, 2011 - 03:38

It should be known that quattro generations 2-4 do NOT use a type 2 torsen. These are all type 1 torsen center differentials.

Reply to Derek
George
February 11, 2011 - 20:02

I think all 5 speed automatics use the Torsen2.
The ZF 6 speed automatic uses a Torsen1.

I don't remember what the early 1990's 4 speed automatics use?

There hasn't been a manual shift transmission 'Quattro' with a Torsen2.

Andre
April 23, 2010 - 16:27

Dave - you were absolutely correct. Any "new" models since the 2005 RS4 have no longer been using Torsen. I just saw this official Audi site that confirmed it (see below). They have been using a "self locking center differential". It appears the "crown gear differential" is an evolution of that.

www.audi-quattro-highlights.com

BTW - where did you find the patent information?

andre
March 05, 2010 - 08:51

www.audiusanews.com

this is the press release about the sport differential a couple of years ago. Most interestingly it is active even when you lift off of the throttle. I wonder how this compares to other systems...??

andre
March 05, 2010 - 08:40

www.audiusanews.com

This link was a part of the press release for the 30th year of quattro....which is why it's launching on the RS5. Apparently they say it's lighter and more compact as far as the center differential. They also explain about "electronic torque vectoring" (which Volvo also notes their new S60 has). My only question is - why move from Torsen and develop a system on your own? I thought they were good parterns but I guess they want a proprietary system (the Lexus LS now licenses the Torsen system)....??

Reply to andre
Andre
March 11, 2010 - 01:03

www.youtube.com

This is the video Audi produced to explain it as well.

Reply to andre
Dave
April 09, 2010 - 13:46

Put simply, three reasons:

1. the patent Audi had for the torsen expired in 2004.
2. The requirement to find lower friction (i.e. more efficient) systems, and
3. to allow fully active control over the torquer split without resorting to EDL.

Hans Simonsen
February 28, 2010 - 11:43
Audi RS5

Hi

A really good description of all the quatro types!
I read that the new Audi RS5 has a new type of differential but I don't understand how it works.
Any plans on updating this page?

Regards, Hans Simonsen

Reply to Hans Simonsen
awdwiki.com
February 28, 2010 - 17:27
Re: Audi RS5

Thanks, I've added this system to the list, but I am still lacking the details, as this is something really new.

Reply to Hans Simonsen
Dave
April 09, 2010 - 13:54
Re: Audi RS5

the static torque bias is created by using differrent gearing between the spider gears and the front and rear crown gears (front smaller). a very neat trick.

there are 2 clutch packs which will progressively lock the respective output shaft to the carrier so preventing spin-up and controlling the torque split.

the carrier, clutch packs and gears are all packaged in a very small "can" whcih allows for lower weight and greater efficiency.

looks like a nice design - fully acive crontol (unlike the torsen). it says a lot when audi releases the rs5 without the sport differential standard - instead making do with EDL-based 4-wheel torque vectoring.

allrad
December 07, 2009 - 23:11
some words to quattro system (Torsen)

As I said before, I've checked that Audi video (test Torsen) some time ago, and I have to say I was very surprised by behaving of Torsen differential. I thought that car will be promptly away from rollers, but he had to accelerate to go away... And now I found this video which I shouldn't see - www.youtube.com !!! Same situation, same result! Can't understand it!

Reply to allrad
awdwiki.com
December 08, 2009 - 18:31
Re: some words to quattro system (Torsen)

Yes, this is a very interesting feature of TorSen. The Quattro II description on this page explains why this behaviour is happening.

In this situation, driver has to apply brakes to the spinning wheels and TorSen will transfer torque to the wheels with traction.

Reply to allrad
allrad
December 08, 2009 - 20:45
Re: some words to quattro system (Torsen)

i think i understood it, according to Torque Bias Ratio of Torsen diff, for example 4,0:1, diff is able to transfer up to 80% of torque to axle with better traction... so the minimal torque on the slipping axle, which can cause limited-slippage, is 20%... if its lower, torsen behaves as open diff and u have to help yourself by park break (in case of slipping rear axle) or lightly pushing break pedal (dunno if it works) (in case of slipping front axle)... in case of torsen in rear axle and one wheel slipping in air, the same process as with slipping front axle (?)...

Reply to allrad
George
January 16, 2010 - 03:49
Re: some words to quattro system (Torsen)

That kind of video shows how disingenuous some people are.
The coefficient of friction of a [grippy] tire and asphalt is about 1.00
The coefficient of glare is about 0.1 [ice really isn't that slippery, it is the ice-water boundary layer that results forms from contact pressure-ergo Blizzak and other similar tires]
The coefficient of rolling resistance of rollers [with quality bearings] is roughly 0.01.
These roller scenarios equate to having your wheels airborne.
The traction difference, neglecting the front biased weight distribution of an A8, slightly better than 60/40, is FAR outside the TBR of 3:1.

Reply to allrad
andre
March 11, 2010 - 01:05
Re: some words to quattro system (Torsen)

George that is a good explanation about tractive force and the transfer of torque. How does the new crown gear compare to the Torsen in that regard?

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