Mazda Files Six Rotary Engine Patents in Japan

Mazda filed six patents related to rotary engines with the Japanese Patent Office on the same day in June, CarBuzz has learned.

The Wankel rotary engine popularized by Mazda will return in the MX-30 R-EV range extender, but these patent applications describe a larger two-rotor design that could actually be used to propel the car, opening the door to a new generation of rotary-powered of Mazda sports cars, and could open the door to a new generation of rotary-engined Mazda sports cars.

Three of the six patents relate to the shape of the rotor itself. The purpose of the patents is to "improve the fuel efficiency of the rotary engine" and address one of the factors that led to the discontinuation of the Mazda RX-8 when its production ended with the 2012 model year.

The patents each show a different design, each with recessed cutouts of unique dimensions. In a rotary engine, the rotor rotates in the center of the housing and the empty space around the rotor serves as the combustion chamber. By changing the shape of the space between the rotor and the outer wall of the housing, these cutouts change the shape of the combustion chamber, resulting in finer control of ignition and more complete combustion.

Three other patents focus on the use of exhaust gas recirculation. This process, in which exhaust gases are cooled in a heat exchanger before being returned to the engine, is already used in conventional piston engines to improve efficiency. The Mazda patent examines the application of exhaust gas recirculation to a rotary engine and describes the design of the intake and how it is attached to the engine

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Mazda has applied for patents before, raising the hopes of rotary engine fans. Earlier this year, Mazda filed a patent for a rotary hybrid powertrain with three electric motors, and a patent application filed by Mazda in 2022 also suggested a rotary hybrid powertrain combined with rear-wheel drive. However, this latest round of rotary patents may not bring anything to the table, as patent applications are not always successful.