Engine - 2010 Mazda RX-8 4-door Coupe Man Grand TouringEnlarge Photo
Fans of Mazda's unique little rotary engine used in the company's sweet RX-8 sports car will be glad to know that Mazda is continuing development of the engine. The company plans to launch an improved version with the power and efficiency of a 3.0-liter V6, said Robert T. Davis, Mazda's senior vice president of product development at a recent press luncheon in New York. But when pressed for a release date for the new "X16" rotary engine, as it's called, Davis wouldn't give any details.
The rotary engine uses triangular extensions that spin around a crankshaft rather than traditional cylinders found in conventional internal combustion engines. This allows it to spin faster and produce a lot of power for its size.
But the current engine in the RX-8 is crude and has many downsides. It produces virtually no power at low speeds - you have to really rev it to get decent boost. It also guzzles gas, with an estimated fuel efficiency of 16 mpg city and 22 mpg highway that's worse than some V8 engines more than twice its size and output.
During a Q&A session, I asked Davis why the rotary gets such poor fuel economy despite being so small, and he said that's because the engine basically uses 50-year-old technology. Mazda is alone in developing the rotary engine and has put it on the back burner for decades to focus efforts on conventional internal combustion engines.
Davis affirmed that the company will not give up on it. In fact, the rotary engine is at the heart of one of Mazda's hydrogen-based alternative-fuel projects because, unlike conventional piston-driven engines, it stays cool near the injection ports and therefore can pump either gasoline or the more volatile compressed hydrogen gas through the same injectors. And having an engine that can switch over to gasoline if the hydrogen runs out with no fueling stations nearby is crucial to the adoption of hydrogen as a viable energy alternative for automobiles, Davis said.