Rotary engineEnlarge Photo
With no successor confirmed, we may never see a rotary engine in a production car ever again, though those at Mazda certainly don’t want to see it this way.
Part of the reason for its demise is its terrible fuel economy, which is around 40 percent worse than a conventional internal combustion engine with comparable performance.
The engine, first launched in the 1967 Mazda Cosmo, did have its pluses, however. From the tidy 1.3-liter unit found in the RX8 came 232 horsepower, which peaked at a lofty 8,500 rpm with the six-speed manual it was fitted to. And for all the revs, it was still smoother than many piston engines with twice the displacement at half the rpm.
Mazda engineers are toiling away with solutions to make the rotary engine ‘greener,’ but so far have had little luck. One strategy is the application of SKYACTIV technology, either with direct injection, supercharging or some other conventional fuel-saving technology.
Another, more radical strategy is the use of the rotary strictly as a range-extender for a battery-powered electric car. According to Bloomberg, Mazda is currently testing a rotary burning hydrogen fuel to charge a lithium-ion battery that then drives an electric motor; in fact, we drove the latest Premacy (Mazda5) Hydrogen RE a couple of years ago and found it to feel, well, much like an electric car but with a rotary functioning as an onboard generator.
Mazda wasn’t the first to proceed down the rotary-powered range-extender development path. Instead, it was Audi that showed the rotary-packing A1 e-tron concept at the 2010 Geneva Motor Show. That allegedly led to talks between Audi and Mazda, and rumors that Mazda was developing a special-purpose rotary engine for the Audi A1 e-tron. It’s likely that such an engine could also be used to power future Mazda range-extended electric cars.
Perhaps then the rotary will come full circle. The unique engine design, after all, was pioneered by German engineer Felix Wankel shortly after World War II, who at the time was working for Audi NSU Auto Union AG and later licensed the technology to Mazda.
Audi A1 e-tron ConceptEnlarge Photo