LA show: ‘Fundamental’ issues delay rotary return

DESPITE Mazda’s desire to resurrect the rotary engine, the project is still at an engineering crossroads, says the Japanese car-maker.

Mazda Motor Corporation’s senior managing executive officer (R&D) Kiyoshi Fujiwara told journalists at the Los Angeles motor show that “fundamental” construction issues are slowing progress.

“The issue is the fundamental structure of the rotary,” he said. “There are the usual issues around fuel economy and emissions, from our point of view, but the issue for us is the fundamental structural issues of the engine.

“We are developing all-new technology to break through these fundamental issues, for example the ignition system.”Mr Fujiwara explained that the basic architecture of the born-again rotary is yet to be signed off, suggesting that using mild turbocharging to overcome the Wankel engine’s inherent disadvantages is just one plan among many being considered.

“Turbocharger systems are one of the answers to help smaller rotary engines, but I don’t know,” he said. “I cannot say at this moment, because it’s still underdevelopment about which system will be better. We have not decided yet.”When asked if this meant that the rotary engine sports car was still some years away, he answered “yes.” Mr Fujiwara confirmed, however, that Mazda’s commitment to the unusual engine format was due to the advantages of small size, low weight and high power at the expense of fuel economy and reliability.

For now, an exact timeline plotting the return of the unorthodox engine is unavailable.

“The RX Vision is the vision vehicle for our designers and our company, so therefore I could not say when, but in the future – I cannot say when – I would like to introduce the rotary engine into our RX Vision models,” he said.

“Today I cannot give you any specifications, but we are still developing this unique technology.”It is likely that the first application - outside of the production of a very small range-extending engine that is unlikely to be connected to a drivetrain – will be a lightweight sports car in the same vein as the company’s RX-7 of the 1980s.

“The rotary engine is suited to performance car, and especially for the lightweight sports car, because of the low torque for the low rpm, therefore we are considering that kind of technology,” he said.

“For the Mazda fan or the rotary fan, (they are) waiting for pure sports car without electrification, I believe, because electrification requires the heavy weight of the battery and other systems.

“More pure high performance models would be required by Mazda fans. As a first step I would like to try pure styles. But with tougher regulations worldwide, we will need to add some technologies like electrification, in a smaller, smarter system.

“But the first step? Pure. That’s the key word.”Mr Fujiwara confirmed that the company’s forthcoming electric vehicle would use a small rotary engine as a range extender, and suggested that – as indicated previously – Mazda is keen to offer the technology to other manufacturers.

“The range extender will be one of our unique technologies, therefore it can help to develop our brand image, especially for rotaries,” he said.

He also revealed that some of Mazda’s bean-counters may not share the enthusiasm for the rotary project as the development team.

“All of the designers and all of the engineers love rotary and sports cars,” he smiled. “Some of the ‘calculators’, though…”