Computational Prediction for NOx Reduction in a Premixed Lean Diesel Combustion Engine

Three dimensional computations were carried out to study the effects of engine operating conditions on NOx emissions from premixed lean diesel combustion in a DI engine. A modified KIVA II computer code was used to the numerical simulation. Qualitatively good agreement between computational and experimental results for impinging fuel spray shape, heat release rate and relative NOx mass has been achieved. The computational results demonstrate that NOx emissions are significantly influenced by temperature of intake air, fuel injection timing, and fuel ignitability. It is also indicated that fuel droplets gathered into the squish region are possible to become unburned fuel emissions.