In a recent interview, a Mazda executive disclosed that the company is exploring a hybrid model that complies with emissions standards and creatively utilizes the Wankel rotary engine.
Historically featured in Mazda’s RX-series sports cars, the Wankel rotary engine is an unconventional internal combustion engine that operates more like a two-stroke engine than a traditional four-stroke. This design leads to benefits such as high power density and a smooth delivery of power, but it also brings challenges including questionable reliability, elevated greenhouse gas emissions, and subpar fuel efficiency.
Mazda has reassessed the rotary engine’s relevance for contemporary vehicles and, in collaboration with Toyota, has adapted the rotary design to serve as a small auxiliary power generator or range extender for electric vehicles. One potential application of this range extender is within an ultra-compact hybrid drivetrain, where the rotary engine can both drive the wheels and routinely generate electricity. This hybrid system, referred to as “XEV” by Mazda, is under consideration, according to Ichiro Hirose, Mazda’s Executive Officer for Powertrain Development.
“We announced that we are considering the integration of a rotary-based range extender alongside battery-electric vehicles,” Hirose stated during his conversation with Australia’s Drive. “This isn’t simply a typical combined solution; it falls under what we categorize as ‘XEV,’ meaning that the range extender and the rotary engine serve dual purposes: generating electricity and providing driving force for traction.”
Hirose elaborated that the XEV drivetrain could enable vehicles to function either as battery-electric vehicles with a small onboard charger or as plug-in hybrids that heavily utilize electric motors while primarily relying on their combustion engines.
“Our goal with this combination is to adjust the balance between battery usage and fuel supply,” Hirose continued. “Depending on the ratio, we could develop a version that operates more like a plug-in hybrid.”
“Conversely, if we shift that balance, it could become a fully battery-electric vehicle, using the rotary engine solely as a range extender. Based on this architecture, we are exploring a broad range of applications for the rotary engine,” he said.
Hirose emphasized the versatility of the “XEV” drivetrain, stating that it can ensure the rotary engine meets global emissions standards, including in environmentally conscious regions such as California.
“Should we launch it in the U.S., we would meet the stringent regulatory requirements while the rotary engine is operational. We have made significant strides in this area,” Hirose concluded. “Theoretically, if we were to enter the U.S. market, we would comply with the most demanding regulations.”
Despite enthusiastic requests from fans of rotary engines for their revival in sports cars, Mazda appears poised to repurpose the engine as a range extender for its first electrified vehicle, which certainly will not be a sports model. When asked in December about the potential return of the RX-series sports car, company officials were notably cautious, suggesting it would be unwise to expect the arrival of a Mazda RX-9 anytime soon.
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