Mazda Developing Inline-Six Engines

Mazda Motor Corp. is developing inline 6-cylinder diesel and homogeneous-charge-compression-ignition (HCCI) engines for fullsize, rear-drive vehicles.

The company currently offers inline-4 and V-6 diesel, gasoline and HCCI engines under its Skyactiv sub-brand. HCCI engines run on gasoline but function like a diesel to ignite their air-fuel mixture through pressure rather than a sparkplug. The 2.0-liter Skyactiv-D diesel (pictured) debuted last year in Europe and bows this year in the U.S.

The new inline engines will be installed longitudinally rather than transversely. The only current Mazda vehicle with a longitudinal engine layout is the rear-drive Miata MX-5 roadster, which is powered by a 2.0-liter 4-cylinder mill.

Mazda’s new “Large Architecture” chassis will be used for several unspecified next-generation models due to launch by 2025. In addition to the inline-6 engine, mild- and plug-in hybrid variants are expected.

Mazda says its SkyActiv engines can improve fuel efficiency by as much as 30%. The company also expects the engines will boost operating profits by the same percentage.