Audi has a Wankel for a range extender. 148.7 mpg (imperial)
Audi A1 -click
Below: the Wankel is so small it fits under the trunk floor:
Audi A1 - report -click
Audi has confirmed the A1 e-tron will be made using the Wankel range extender.
A1 to be made -click
GM did heavy Wankel...