Mazda SKYACTIV-X won't replace diesel

Mazda may be the first company to launch a mass-production compression-ignition petrol powerplant, but that doesn't mean it has stopped development of its turbo-diesel or conventional petrol engine lines.

In fact, the boss of Mazda Motor Corporation powertrain and vehicle development, Ichiro Hirose, says conventional petrol engines have a strong future and is tipping a return to favour for turbo-diesels down the track.

Mazda will use the all-new, fourth-generation Mazda3 to debut its ground-breaking spark-controlled compression-ignition SKYACTIV-X petrol engines and is tipped to offer the technology in the new model Down Under before the end of 2019.

Carsales.com.au experienced the new engine technology in a prototype drive last year. No detailed performance claims have yet been given, however, Mazda personnel are suggesting better than diesel fuel economy for the new SKYACTIV-X equipped Mazda3.

Speaking to Australian media at the 2018 Los Angeles auto show, Hirose stated that significant refinements had been made to the system since the prototype drive. He also confirmed that Mazda was working on a range of SKYACTIV-X engines of differing displacements.

It’s now clear the company will progressively introduce the engines across its passenger car and SUV model ranges.

Most importantly, for markets like Australia where the majority of Mazdas are powered with the company’s conventional SKYACTIV-G petrol engine family, Hirose confirmed that development was also proceeding apace.

“[SKYACTIV-] X is not necessarily replacing G [petrol] or D [turbo-diesel] -- our plan is to make sure that G and X and they all coexist,” he said.

“We [then] decide which powertrain to apply to which models and what is optimum for the market… The G engine is going to be improved continuously,” Mazda’s development boss confirmed.

Hirose also provided details of the mild-hybrid system Mazda has developed to pair with both SKYACTIV-X and SKYACTIV-G petrol engine families.

In the just-unveiled 2019 Mazda3, the system features a belt-driven ISG (integrated starter generator) which charges a 24-volt lithium-ion battery pack during deceleration.

The battery pack is flat-packed into the vehicle’s floor structure (in part necessitating the new Mazda3’s 25mm wheelbase stretch). Recovered power stored in the pack is then used to boost performance.

When quizzed on regulatory moves to kill off internal combustion engines (and in Europe, turbo-diesels in the relatively short term), Hirose was unconvinced.

“I understand what is happening but in Europe vehicles [still] drive for long distances and they drive SUV as well. And in terms of really reducing CO2 emissions, diesel engines are really a better [solution] when people are driving long range. So, I don't think diesel engines will disappear entirely.”

Hirose confirmed Mazda was also working on the new-gen diesels.

“The diesel engine itself is going to keep improving,” he said. “Actually, we are currently working on the development of the second-generation SKYACTIV-D,” he advised.

“I think some day in the future diesel engines will make a comeback. That's my strong belief,” he stated.