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Mazda accelerates R&D of rotary engines adapted to new era

Mazda Motor Corporation (Mazda) will accelerate its research and development of rotary engines (RE) that are adapted to the new era in its efforts to continue to deliver the joy of cars through solutions that are appropriate for the times toward the realization of a carbon-neutral society.


Electric drive unit of Mazda MX-30 e-SKYACTIV R-EV

The RE Development Group has been reinstated in Powertrain Technology Development Department of Powertrain Development Division on 1 February 2024, preluding a sequel of the RE story. The new RE Development Group will continue to evolve RE used as generators, and will conduct research and development in areas such as regulatory compliance in major markets as well as the application of carbon-neutral fuels.

For the last six years, RE engineers have been part of the engine development organization where they engaged in the development of state-of-the-art internal combustion engine functions as well as the ultimate improvement in efficiency. Those engineers have broadened their perspective beyond the boundaries of engine systems, and have trained themselves to master the ‘Model-Based Development,’ which is one of Mazda’s engineering strengths. This time, 36 engineers will gather in one group to make a breakthrough in the research and development of RE. In the age of electrification and in a carbon-neutral society, we promise to keep delivering attractive cars that excite customers with our ‘challenger spirit.’

—Ichiro Hirose, Senior Managing Executive Officer, and Chief Technology Officer (CTO)

Mazda was the first to install RE in the Cosmo Sport introduced in 1967, and for many years since then, Mazda has been working to improve performance in terms of output, exhaust-gas purification, fuel economy, and durability as the only automobile manufacturer to mass-produce rotary engines. In June 2023, the company resumed mass production of vehicles with rotary engines for the first time in approximately 11 years since the end of production of the Mazda RX-8 in 2012. Currently, the Mazda MX-30 e-SKYACTIV R-EV, the 12th model that mounts a rotary engine, has been introduced in Japan and Europe.



I like the idea of a single rotor range extender it just makes so much sense in front wheel drive rear wheel drive sedans coupes SUV whatever you got.


@SJC, yes, I am keen on the notion of a range extender for BEVs. However, it needs to be small and light and reasonably powerful (30 kW ?) and cheap.
IMO, the problem is all the surrounding equipment like the exhaust and the catalyst and the cooling and fuel system. The range extender+ its battery should be lighter than the pure BEV system.

Albert E Short

Going back to the Volt, PHEV's have been parallel (ICE sometimes goes straight to transmission, most often at highway speeds) rather than pure serial (only electric drive) to deliver a better overall fuel efficiency. The Holy Grail was an ICE/generator set efficient enough to deliver enough juice at an acceptable MPGe in a serial setup. I don't think the MX-30 is there but Mazda has been implying this is imminent since last year.

Roger Pham

Mazda MX-30 has horrible fuel efficiency in the hybrid mode, around 33 MPG in real life driving, in comparison to the 38 MPG of the Toyota RAV4 Prime which is a bigger SUV. Mazda has cancelled plan to sell the MX-30 PHEV in the USA, not surprisingly, due to the lack of power, 168 hp in comparison to 304 hp of the RAV4 Prime, and the poor efficiency of the MX-30 PHEV.

Apparently, Toyota's serial hybrid design is a lot more efficient and more powerful than the serial hybrid design of the MX-30 PHEV, when both the engine and the e-motor can contribute power to the vehicle. With mechanical coupling of the engine to the drive train during cruise, electrical resistance loss is avoided, to allow higher efficiency in the hybrid mode.

What I would like to see, however, is that Toyota would reduce the engine size on PHEV model due to higher power from the battery. In this way, the PHEV version will not be heavier nor cost much more than the hybrid version. For example, the Prius Prime could use the 3-cylinder 112 hp engine instead of the 4-cylinder 149 hp engine.


The single rotor is small and light can produce 100 horsepower peak you can easily get 50k out of a motor alternator so go ahead and put two differentials to motors all wheel drive and then drive the front directly clutched in for engine participation.

Ski Milburn

Colorado is not alone in projecting the production cost of Hydrogen to decline to under $3/kg by 2030, Plug Power and others recently making same claims and plans. That suggests retail H2 cheaper than gasoline before 2040.

I mention this here because the Wankel rotary has already been proven to be particularly well suited to running on gaseous fuels such as Hydrogen. In a future world of 50 kW range extender battery-electric vehicles, this could be a real contender.

Maybe Mazda crazy like fox! Wouldn't be the first time.

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