Mazda Files Patent for Rotary Engine Fix That Could Solve Its Biggest Weakness

Mazda has filed a new patent for an exhaust gas recirculation (EGR) system designed for rotary engines, according to a recent filing with the US Patent and Trademark Office. This move suggests the automaker is still working to bring a Wankel engine back to a production car, despite the challenges that killed the old one.

Older Mazda rotaries lacked EGR systems because emissions rules were looser decades ago. The new patent describes splitting the rotary housing’s exhaust pathways between side and peripheral ports. The side-port exhaust would feed a turbocharger, while the peripheral port would send gases through an EGR cooler to lower air temperatures.

Under heavy load, that cooled air could flow directly into a secondary catalytic converter, helping reduce emissions without sacrificing performance.

Mazda has teased new rotaries with recent concept cars, including the Iconic SP and last year’s Vision X-Coupe, which featured a turbocharged rotary. However, getting a Wankel through modern emissions and durability testing for a production model is a major hurdle. While this patent doesn’t confirm a new rotary sports car is coming soon, it shows Mazda is investing in keeping the engine alive, even as the industry shifts toward electrification.

Whether a production version of those concepts will appear remains unconfirmed, but any new rotary would be a welcome addition.