AWC in '08-Current Ralliart Explanation
 

This is a cut and past from literature provided by Mitsubishi Canada. The Ralliart has a different system than the Outlander and Evo.

UNDERSTANDING ALL-WHEEL CONTROL (AWC) – LEVEL II
The most sophisticated AWC system offered in the Mitsubishi line-up is found in the Lancer RALLIART(and Lancer Sportback RALLIART). Unlike the system found in the RVR / Outlander Sport and Outlander ES & LS, the front to rear torque split is managed by the electronically controlled hydraulic clutches found in the Active Center Differential (ACD).
In addition to containing the clutches responsible for managing the front to rear torque split, the ACD also contains a helical Limited Slip Differential (LSD).The LSD constantly biases torque to the front wheel that has the most traction. Under straight-line acceleration, power remains evenly split between the front wheels. When accelerating out of a turn, the LSD directs power away from the inside wheel and toward the outside wheel. A mechanical LSD performs that task for the rear wheels.The net result is a vehicle that allows the driver to accelerate earlier out of a turn and exit at a higher speed, without losing traction.

AWC as used in Lancer RALLIART applications has three settings:
Tarmac – Provides a rear bias for improved performance under optimal conditions
Gravel – Splits torque equally to ensure balanced handling characteristics under lower traction conditions
Snow – Provides a front bias for more forgiving handling characteristics under slippery conditions