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.