Diesel engines have been extensively used in Europe for passenger cars, light and heavy duty vehicles. A very strict regulatory is effective in Europe, US and Japan to have cleaner vehicles and reduced fuel consumption. As a combustion strategy for light loads, premixed combustion presents great results in terms of NOX and Soot emissions. However, mid and high loads cannot take full advantage of this concept due to hardware limitations. Is there a way to obtain a Clean Diesel engine with a diffusive combustion? Based on recent research, it seems to be feasible to develop Diffusion-flame Low temperature combustion concept avoiding simultaneously NOX and Soot emissions. The strategy is based mainly in a significant reduction of the equivalence ratio at the lift-off length cross section and the combustion temperature, maintaining the conventional mixing controlled diesel jet structure.