Patfromigh pointed out that, according to publicly available Department of Energy files, Chrysler is experimenting with a mild hybrid, similar to the General Motors system. Both use a belt alternator starter/belt starter generator (BAS/BSG) to provide stop-start, regenerative braking, and low-speed motor assistance. Chrysler’s main difference from GM is the use of an electric belt tensioner, and much greater use of fuel shutoff during deceleration (“iDFSO”).
Current Chrysler vehicles with automatic transmissions already use iDFSO, which cuts off the fuel supply to the engine when the driver coasts, as long as all the right conditions are met (hot catalyst, sufficient battery power, warm engine, etc). GM had a similar system in use decades ago, but for manual-transmission cars (when coasting in gear).
The BSG system was added to allow iDFSO all the way down to a full stop; standard iDFSO is normally available down to 15 mph, and the alternator/starter provides the rest of the capacity. The electric belt tensioner is needed to tighten the belt during power generation, and loosen it during normal motoring. Enhanced voltage regulation and fluid temperature control are also part of the system, as they are in Ram 1500, to cut parasitic losses.
From these documents, it appears that the Department of Energy program to work on fuel reduction has resulted in a transfer of technology to production vehicles — at least, to the 2013 Ram 1500.