Mazda SKYACTIV-X tech to fast-track rotary development

Mazda says it plans to implement teachings from its SKYACTIV-X petrol technology into development of a new rotary engine.

The Japanese car-maker has already confirmed it is working on a ‘rotary engine range extender’ for a forthcoming production electric car, at the same time fuelling speculation it is concurrently developing a born-again rotary-powered RX sports car.

Speaking at the launch of the Mazda3 SKYACTIV-X in Germany this month, Eiji Nakai, the executive officer in charge of Mazda’s powertrain development, said progress on Spark Controlled Combustion Ignition (SPCCI) will be transferred to the long-running rotary program.

“For the rotary engine, of course we continue to research and study. But when it comes to the mass production timing, we still haven’t decided yet,” said Nakai-san, while quietly batting away any ‘RX-9’ speculation.

“There are a host of learnings that we can apply to the rotary engine. Rotary is just the same internal combustion engine as SKYACTIV-X – running the engine in such a manner, how to create the air-fuel mixture and we’re going to ignite the air-fuel mixture.

“That knowledge is something that we can apply, even to the rotary engine. We cannot give you specific timing but we are doing our best.”

Mazda last ran a rotary engine in the RX-8 sports car, which was discontinued in 2008. However, the car-maker has confirmed it is developing a new version to be used as a range-extender in an electric car.

Emissions and efficiency problems have plagued the rotary engine for decades, and rotaries have never been known for their breadth of accessible of power. However, the rotary’s compact dimensions and power delivery traits are considered ideal for use as an EV range extender.

Mazda has already proved the concept of a shoebox-sized single-rotor engine acting as a generator in an EV prototype based on the Mazda2, and Audi toyed with the same idea in its A3 e-tron but later switched to a conventional engine/generator.

“The rotary engine’s small size and high power output make multiple electrification technology solutions possible via a shared packaging layout,” the car-maker recently said.

“Taking advantage of the rotary engine’s compatibility with gaseous fuels, the rotary-powered range extender is designed to also burn liquefied petroleum gas and provide a source of electricity in emergencies.”

On the performance front – read, RX-9 -- Mazda appears to have made key inroads in recent months, filing two patent updates for a new side-port exhaust arrangement and a new turbocharger design that is bespoke to the rotary powerplant.

The new, overlapping peripheral exhaust port, reciprocating valve system and turbine-style turbocharging suggest the new rotary engine will be used to power a vehicle.

Crucially for Australian EV and/or rotary fans, however, Mazda made it clear its first electric vehicle won’t be sold in countries that generate large amounts of electricity from coal-fired power stations like ours.

“Mazda is committed to reducing its corporate average ‘Well-to-Wheel’ CO2 emissions to 50 per cent of 2010 levels by 2030, and to 90 per cent by 2050,” the car-maker said.