Even if it can't overcome the rotary's efficiency limits compared to piston engines, it's small and smooth and only used a small portion of the time for long tr

Even if it can't overcome the rotary's efficiency limits compared to piston engines, it's small and smooth and only used a small portion of the time for long trips. If a bigger/heavier engine could charge the battery more efficiently, but you only use it 1% of the time and the other 99% of daily commutes you're draining your battery to carry a bigger engine around, is it really more efficient? Hopefully someone at Mazda has run those numbers and they figured that for a range extender, this was the best solution.