I thought the same thing when I read the first description. But as an owner of an Rx7 (mazda's rotary car), I can assure you they are not very clean. In fact,

I thought the same thing when I read the first description. But as an owner of an Rx7 (mazda's rotary car), I can assure you they are not very clean. In fact, they tend to do worse on emissions testing than cars from the same era, at least my older one does (an '88). Also, the "shockwave" part suggests this may not have sparkplugs...? If this engine really can combine the exceptional power-weight ratio and small size of the rotary with modern fuel efficiency and emissions control, it could be a legitimate contender. I don't really get why the article claims it is good for hybrids though; is it just the weight factor? You could make a small rotary hybrid right now if you wanted, if weight was the issue.