The rotary engine has been absent on the frontline for quite some time, and it's on the way back. But not with Mazda.

For more than a decade the name Wankel has popped up whenever car enthusiasts start talking about advanced-design automotive powerplants. The theory of the Wankel engine goes back to 1954 when Dr.

You'd think measuring an engine's displacement would be simple, but there's a long history of trying to figure out how to categorize the Wankel.