Forgeworld recently published rules for the Land Raider Proteus. Part of those rules that caught my eye was the infernal device entry for chaos versions of the land raider. In short, it is the analogue of the Imperial power of the machine spirit. It allows one more weapon to be fired than would be permitted (given the speed of the vehicle), potentially at a different target, and allows a single weapons to be fired even if the vehicle has been whacked with a crew shaken/stunned result.
I suspect (hope!) that this is a foreshadow of things to come for chaos space marines.