Mazda 3-rotor hybrid engine plans discovered in patent filings

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There have been rumors that Mazda has been regularly reviving the rotary engine since production of the RX-8 ceased in 2012. The company itself has been pretty quiet about the rotary engine, except as a planned range extender in an upcoming plug-in hybrid version of the MX-30. However, Mazda has filed a patent application for a three-rotor hybrid powertrain. And unlike the MX-30, not only does it appear to be the main propulsion unit, but it’s also configured for a rear-wheel drive layout.

According to Japanese blogger taku2-4885, the patent has been filed with the European Patent Office. One of the detailed diagrams clearly shows a rotary motor with three housings, which are similar in architecture to the triple rotor found in the Japanese market Eunos Cosmo in the early 1990s. The rotary engine is connected to a 48-volt mild-hybrid assist system and a rear transaxle, similar to a Japanese patent for an RX-Vision-style coupe discovered in August. There is also a description of a cooling system, something the hot-running rotary engine needs to maintain a long life.

Unlike those Japanese patent applications, these illustrations are not nearly as detailed. They’re probably a placeholder for something Mazda would like to do one day, when market forces and planets align. Of course, the gap between that and a production car is incredibly wide.

And given the way the market winds are blowing, it seems increasingly unlikely that any new combustion engine, especially one with a design known for its thirst and emissions, will enter production. Mazda must be concerned about increasingly strict regulations on electrification and emissions, especially in Europe, if it is to continue to sell cars in those markets in the future. It would not be cheap not only to develop, but also for people to buy.

We wouldn’t say it’s a completely hopeless case either. Mazda has not yet given up on the turntable, which is apparent from the range-extender plans. If the partnership with Toyota bears electric fruit that allows Mazda to survive, we see a slim chance that a PHEV variant of this car exists. In all-electric mode, it would still be allowed in European city centers that have banned petrol engines altogether. However, it would certainly take something more powerful than just a 48-volt electric motor to be a plug-in hybrid.

There are countless other factors that work against a three-rotor RWD performance car, but we love that Mazda, once the dreamer, considers even such a thing.

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