A rotary redux?
After years of hints, promises and denials, Mazda finally appears to be moving towards the re-launch of its once-familiar rotary engine, with a concept model said to be in the works for 2017, and a production model to follow three years later.
But the revived rotary may serve a very different purpose going forward, showing up as part of a plug-in hybrid that would take advantage of the compact engine’s advantages while offsetting its traditional design limitations.
Several senior executives have discussed the company’s options with TheDetroitBureau.com in recent years, including several directly involved in the program. They have made it clear that Mazda would like to offer a so-called Wankel engine in its portfolio. The unusual powertrain was a signature of the brand when it first burst onto the American scene in the late 1960s and early ‘70s.
But they also have repeatedly cautioned that critical disadvantages of the engine would have to be overcome before that could happen.
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It helps to have a basic understanding of the rotary which foregoes the pistons of a conventional internal combustion engine in favor of a spinning, triangular rotor. The concept develops significant amounts of power in a small amount of space. But it has inherent issues that have traditionally meant poor fuel economy and high emissions.
With regulators around the world tightening clean air and mileage rules, major breakthroughs would be needed for the rotary to come back in today’s automotive environment.
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Apparently, Mazda feels it has made enough progress to schedule a concept to debut in 2017, which would conveniently mark the 50th anniversary of the Cosmo Sport, its first Wankel-powered model. And a production version is said to be on tap for 2020 which would help Mazda celebrate its centennial.
But if insider reports prove accurate, the new RX-9, as it apparently will be called, will be radically different from Mazda’s previous rotary designs. It will use the 450-horsepower Wankel as part of an extended-range hybrid-electric powertrain, which would also be Mazda’s first plug-in model.
Specific details are unclear. For one thing, Mazda insiders have not disclosed whether the rotary on the RX-9 would be used solely as a generator, or might also provide some torque directly to the driven wheels, as is the case with the BMW i8 plug-in sports car.
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Operating the rotary solely as a generator would offer some significant potential advantages. The rotary can be reasonably efficient when operating at a steady speed, rather than racing up and down the rev range as a vehicle’s primary source of power. That approach would also make it easier to control its exhaust emissions.
Considering the 54.5 mpg fuel economy standards coming to the U.S. in 2025, with significant new mandates coming into place in Europe and Asia, as well, Mazda apparently believes its next-generation rotary can make a huge leap forward however it is set to work under the hood of the upcoming RX-9.