Quote:
Originally Posted by bailyhill
Highlanadpete
That is my point. The differential cannot generate torque, it can only divide it between the wheels. I think this can be done with braking or it can be done with some sort of clutch arrangement that engages one side and disengages the other. I know what torque vectoring does, my question is how does it actually do that?
Bailyhill
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Sorry, misunderstood your question.
There's a clever, but quite complex, double sun and planet gear drive with a clutch pack, one a side for each drive shaft. The closed clutch is (from memory) a 1.1:1 ratio.
So driving with a bit of purpose, sensors (including the steering sensor) feeding back data you are entering or in a bend, closes the clutch on the outside wheel, increasing the speed of the drive shaft on that side of the vehicle, (up to 1.1:1). Clutch slip compensates for the exact wheel rotational differences side to side, or one wheel would have to slip or spin. We understand that slip, as it's similar to the transfer box clutch pack in the xDrive, which moves torque rear to front.
That extra (geared up) wheel speed translates as extra torque to the outer wheel. Helps for a more neutral turn in, using the outer rear wheel to help reduce the tendency to understeer.
Shame it is so complex, or we'd likely see it available for less expensive models. The concept makes so much sense for press on driving.