Despite constantly denying it.
If there's one thing Mazda is known for, engine-wise, it's the rotary. However, the last Mazda to feature the thirsty yet unique rotary engine was the RX-8, discontinued in 2012. Despite repeated rumors and even that stunning RX-Vision concept, Mazda executives have regularly denied the existence of a new rotary program. But today we have proof claiming otherwise. Autoblog did some digging and uncovered a couple of new patents Mazda filed with the US Patent and Trademark Office.
The first one describes a range-extender EV on par with the BMW i3, meaning there's an electric motor driving the front wheels, while out back there's a gasoline engine providing power to an electric generator. A lithium-ion battery is located in the middle of the vehicle. But it's the second patent that's far more interesting. It's essentially an engine start-stop system specifically designed for rotary engines. Like regular piston engines, the tech shuts down the rotary engine when it's not needed. But where it gets interesting is that it stops the rotor "in a position that closes the intake port to ensure no fuel or exhaust emissions slip through the intake tract."
Remember, a rotary engine doesn't have any valves, so this latter step is a must. Also described is the concept of "firing a spark plug after the fuel has been cut to eliminate any leftover fuel emissions." Interesting. This new tech would hopefully improve fuel economy and emissions. Now, here's where things get even more interesting: that rotary engine start-stop patent is also combined with the range-extender powertrain patent. Think about it. By combining the technologies together, Mazda can, theoretically, still use a rotary engine, only one that's combined with a start-stop system, an electric motor, and lithium-ion battery.
Because of the rotary engine's small dimensions, vehicle weight can also be kept in check. Obviously Mazda still hasn't confirmed a rotary return, but patenting this tech isn't just done for nothing, let alone spending money on R&D. We'll have to see where this goes, but the news is looking good for Mazda rotary fans.