Mazda:: turbochargers a ‘costly’ solution to efficiency

Mazda has claimed that its next-generation of Skyactiv engines will deliver a further 30 percent fuel efficiency gain without the need for turbocharging as the company seeks to find the ‘perfect’ and leanest naturally aspirated engine.

Speaking to the Australian motoring media at the Los Angeles auto show today, Mazda’s managing executive officer in charge of global sales and marketing, Masahiro Moro, said turbochargers for efficiency and power gain are a costly and non-ideal solution.

“We believe [that] down size turbo solution is much more costlier than our solution” Moro said.

“So if you have to make eight cylinder into six cylinder this downsize makes sense, because you take out two [cylinders] and put in a turbocharger, but four cylinder small displacement and putting in turbocharger is to us more costly.”

Mazda’s focus on naturally aspirated internal combustion engines (ICE) has gone against the form of other car companies that have poured resources into smaller capacity turbocharged powertrain. Something that is unlikely to change for the Japanese brand in the near future as Moro admitted that work on turbocharged engines in the Skyactiv family are not a big focus.

“Not really, as long as petrol engines are concerned. Our internal combustion engine characteristics works better with normal aspiration engine, so we would continue development of normal aspiration as planned.”

The quest to create the “perfect cylinder” continues at Mazda with Moro stating that the number of cylinders is not as relevant once this aim has been achieved, with the company seeking to create a cylinder that burns “fuel the most effective way”.

Other car companies such as BMW, which only sells turbocharged vehicles across the range, have stated that the naturally aspirated petrol engine is now closer than ever to its maximum efficiency capability, with technologies such as turbocharging and electrification a necessity for further improvement, a point that Mazda contests, with its aim to create naturally aspirated petrol engines that are a further 30 percent more fuel efficient than its current range.

“Probably many people still don’t believe [that we can achieve these further efficiency gains] but maybe, you can better believe us now compared to four five years ago.”

Mazda's SkyActiv-G Generation 2 range of engines are set to have a compression ratio of 18:1 to allow the use of homogeneous charge compression ignition (HCCI), a technology that allows well-mixed fuel and oxidiser (such as air) to be compressed to the point of auto-ignition, a technology that Mercedes-Benz and General Motors are also actively working on.

Regardless of the company's focus on naturally aspirated engines, Mazda is reported to be working on a 2.5-litre turbocharged engine for the next-generation of MPS vehicles as well as medium and large SUVs.