torsen automatically locking differential(Edit)
The original Torsen T-1 (Type A) uses crossed axis helical gears to increase internal friction. The Type I can be designed for higher torque bias ratios than the Type II, but typically has higher backlash and the potential for Noise, Vibration, and Harshness (NVH) issues, and requires a precise setup/installation.
The later Torsen T-2 (Type B) uses a parallel gear arrangement to achieve a similar effect. There is also a specialist application of the T-2, known as the T-2R (RaceMaster).
The latest Torsen T-3 (Type C) is a planetary type differential, in that the nominal torque split is not 50:50. The Type C is available as single or twin version; the Torsen twin C differential has front and center differential in the same unit.
(Source: Wikipedia)
Figure: Torsen type II automatically locking differential
Figure: Audi's Torsen center differential (6)
Figure: Audi's Torsen type 1 center differential
Figure: Audi's Torsen type 1 center differential, disassembled
Figure: Torsen type II (left) and Torsen type I
Figure: Torsen type III planetary gear differential
Figure: Torsen type III planetary gear differential on Audi quattro
Figure: How does Torsen differential work. Operating principle.
