Rotary engine

Rotary engine

With the RX-8 sports car expected to be discontinued after the current model year, Mazda, the last bastion of the Wankel rotary engine, will be without a car in its lineup featuring the free-spinning engine. Why the predicament? Because Mazda just can’t seem to engineer the rotary to meet its own internal fuel economy and emissions standards.

The rotary engine is a love-it or hate-it piece of engineering. Marvelously simple and compact yet viciously inefficient, variants of the spinning triangle have seen use in Mazda's cars for over 40 years. But that robust classic tech won't do the job anymore. It’s a well-known fact that the 13B twin-rotor engine in the current RX-8 is a gas-guzzler, rivaling some V-8s for thirst, and in yesterday’s technology preview Mazda didn’t reveal any details about a new generation rotary.

However, according to Mitsuo Hitomi, Mazda’s powertrain chief, development of a new rotary engine, dubbed the 16X because of its 1.6-liters of displacement, is ongoing but still years away from production.  

Hitomi revealed that the 16X engine is currently around 30 percent more fuel efficient than the 13B engine in the RX-8 sports car and about on par with a 2.0-liter four-cylinder in terms of fuel economy and emissions. But sadly, this level of performance is at least one model year behind schedule so it may take another two years for Mazda to further improve the design and announce production, Hitomi conceded.  

The good news is that for Mazda at least, dropping the rotary engine is not an option. But getting more out of the rotary design while decreasing emissions and fuel use is certain to be a hefty challenge--especially while still meeting necessary cost and durability goals.