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Mazda Has Patents for a Rotary Range-Extended EV

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Mazda2 PHEV with rotary range-extender

Being discussed for the next-gen Mazda2: a Mazda2 PHEV with rotary range-extender

Ever since Mazda revealed its RX-VISION concept car and reaffirmed its commitment to working on rotary engines, speculation has been wild on where the brand’s most unique engine might resurface.

Some have hoped that Mazda might bring the engine back with a sports car like the RX-VISION, with one Japanese car magazine even citing anonymous sources saying that the RX-9 was only a matter of waiting until 2020, although that rumor should be ignored entirely, as Mazda CEO Masamichi Kogai himself said that the brand had no plans to bring any sports car, much less a rotary one, to market at any time soon.

However, that does leave one possibility: a rotary engine as a range extender on an electric Mazda.

Enter a far more reliable indicator of things to come than Japanese car magazines: the United States Patent and Trademark Office.

The good people at Autoblog found a pair of patents which were filed last September, bearing a strong resemblance to a Mazda concept from 2013 called the Mazda2 RE Range-Extender (which led to probably the strongest possible rumor).

The first patent was basically the same as that concept, describing a vehicle with an electric drive unit in the front, a battery in the middle, and a compact rotary engine in the rear to generate electricity.

Mazda range-extended EV patent drawing

The second patent built on the first, and described a stop/start system for a rotary engine where the rotor stops in a spot that closes the intake port so no extra fuel or exhaust can slip through, and also possibly has a spark plug fire after fuel is cut to eliminate any leftover fuel in the chamber. This would increase efficiency and cut emissions, problems that killed the use of rotary engines in the first place.

Mazda rotary stop/start system patent drawing

Both patents use the same drawing of a range-extended powertrain, and were filed on the same day.

This powertrain system, combined with stop/start technology, would take good advantage of the rotary engine’s strengths—namely its smooth operation and small size relative to power production—while mitigating its weaknesses.

Here’s hoping, although we never did see anything come out of the last Mazda rotary patent we all got excited about.

News Sources: AutoblogUS Patent and Trademark Office for Range-Extended Vehicle, US Patent and Trademark Office for Rotary Stop/Start