Bad news for fans of diesel passenger cars, it seems.

Mazda said today that the launch of its new SkyActiv-D diesel engine would be delayed past the previous date of sometime this spring.

A terse press release attributed the delay to the time required for "further deliver the right balance between fuel economy and Mazda-appropriate driving performance."

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Mazda noted in its release that the diesel SkyActiv engine can meet current emission limits without the use of a urea-injection aftertreatment system--unlike virtually any other new diesel engine planned for future U.S. sales.

That would not only be a technical coup for the small Japanese company, but it would significantly reduce the cost of fitting the diesel engine, which is derived from Mazda's highly efficient line of SkyActiv-G gasoline engines launched in 2012.

Those engines are now offered in its Mazda 3 compact sedan and hatchback and its CX-5 compact crossover.

Translated, we suspect this morning's announcement means the diesel is clean and fuel-efficient, but too slow to match the Mazda "Zoom-Zoom" image.

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Is there a new target date? Not yet.

The last significant paragraph of the release said simply: "Further information on the program, including a timeline of launch for North America, technical specifications, and fuel economy will be available at a later date, closer to launch."

The company's first diesel vehicle (in 30 years) had been expected to be a model of its recently redesigned Mazda 6 mid-size sport sedan.


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