Cute but I'm calling BS on any system that claims to be more efficient by first compressing air only to expell it via a piston / crank system.
Anyone that's spent 5 minutes in a garage knows how much power it takes to run a serious compressor- even for basic air tools.
NO WAY IN HELL are they going to power any compressor design that is capable of moving an auto with anything less than a motor that would be better suited to just driving the transmision directly anyway.
It's called entropy folks! You'll never break the first law of thermodynamics.
http://en.wikipedia.org/wiki/Entropy
My design for steam generation via exhaust cycle heat recovery / inertia assistance makes a hell of a lot more sense than that!