Computational prediction of NOx reduction characteristics of premixed leandiesel engine

Three-dimensional computations were carried out to study the effects of eng ine operating conditions on nNO(x) emissions from premixed lean diesel comb ustion in a DI (Direct fuel Injection) engine. A modified version of the KI VA II computer code was used for numerical simulations. Qualitatively good agreement between computational and experimental results of the spatial dis tribution of impinging fuel sprays, the heat release rate, and the relative NOx mass have been achieved. The computational results demonstrate that NO x emissions are significantly influenced by intake air temperature, fuel in jection timing, and fuel ignitability. It was also shown that fuel droplets which enter the squish region can later contribute to unburned fuel emissi ons.