Making driving less energy-intensive than flying
DLR researchers visualize blade tip vortices from in-flight helicopter in three dimensions

Mazda delaying SKYACTIV-D diesel launch in North America; further tuning of fuel economy and performance required

Mazda North American Operations is delaying the introduction of its SKYACTIV-D diesel engine (earlier post) in North America from the original targeted Spring 2014. Mazda said that the although the SKYACTIV-D can meet emission regulation requirements without the use of a NOx after-treatment system, it decided that further development is required to deliver the right balance between fuel economy and “Mazda-appropriate” driving performance.

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.

As described in 2011, the 2.2L SKYACTIV-D engine would reduce fuel consumption compared to the current 2.2L MZR-CD diesel by 20% due to a low 14:1 compression ratio and subsequently greater expansion phase after combustion.

The low compression ratio decreases compression temperature and pressure at TDC; consequently, ignition takes longer even when fuel is injected near TDC, enabling a better mixture of air and fuel. The formation of NOx and soot is alleviated since combustion becomes more uniform without localized high-temperature areas and oxygen insufficiencies. Furthermore, injection and combustion close to TDC make a diesel engine highly efficient.



1. The time for debuting the Mazda6 diesel was the second half of 2013. As reported here by USA Today in Sept 2013, the introduction of Mazda6 diesel was delayed to late spring of 2014. []

2. May be Mazda will realize, like some other Japanese automakers, that it is almost impossible to meet the demand of U.S. emission requirement without urea treatment or other catalyst.

The comments to this entry are closed.