Yup... and Wankels are not very fuel-efficient engines to begin with, compared to piston engines of similar horsepower. It looks like they've managed to recapture some waste heat and use it, upping the efficiency, but these claims sound terribly speculative.
Also, what's with the "the exhaust spins the rotor that drives the wheels" part? That sounds a lot like the old Chrysler Turbine setup. The diagram shows no connection between the compression and drive rotors, not even a viscous coupling. The vehicle better be small and light, because I suspect this design will share another Wankel characteristic - low torque. Efficiency is great, but if it can't do the work...