How exactly does Torque vectoring with the crown diff?

[tristatez28lt1]

I know what torque vectoring is and have watched the YouTube audi videos. i was just wondering what exactly it does and how (what part).

I know we have some incredibly knowledgeable people her, so please get as technical as possible.

Thanks a lot in advance guys!

 

[martinbo]

My first response is a question. Why do you ask about how torque vectoring (works) with "the crown diff"?

I can only assume that you're referring to the new crown-gear centre differential in the latest generation of quattro as seen on sat the Audi RS4/RS5? In this case the centre differential has no other influence on torque-vectoring than to send up to 85% of the available torque to the rear axle.

It's at the rear axle where two types of torque-vectoring have been implemented to manage the distribution of torque left-to-right in order to dynamically influence the cornering attitude of a car. My definition of the two types are:

a) passive torque vectoring; here the braking system is used to brake a left or right wheel in order to achieve a desired yaw result depending on whether the vehicle is under or oversteering. This can be employed with both open and limited-slip rear differentials - the latter as in the case with Porsche PTV in certain 997.2 Turbo models.

b) active torque vectoring where a specialised rear differential makes use of superimposed gear sets on the sideshafts which are boosted by electric motors. This has the effect of applying additional rotational force to the desired wheel through torque multiplication in order to achieve a certain yaw result depending on the situation.

In either case, torque vectoring is used most predominantly to mitigate understeer in all-wheel drive vehicles. This, however, has little association with the crown-gear centre diff. There are, of course, exceptions such as McLaren's 12C which uses torque vectoring to achieve an optimal cornering attitude in a RWD vehicle.

 

[tristatez28lt1]

Thank you very much martinbo!