This work presents the development and implementation of combustion model for DI diesel engines by using the PDF-Chemical Equilibrium combustion model. The key concept of this approach is to predict the thermochemical variables (e.g., temperature, species mass fractions) and then the average scalars of these variables are evaluated by a probability density function (PDF) averaging approach. To realize flame propagation, the reaction time scale is employed to relax the infinitely fast chemistry of chemical equilibrium. The PDF-Eddy Break Up ignition model is adopted in the auto-ignition calculation. With regard to the comparison results, the simulation results are in good agreement with the experimental results in both ignition and combustion modes. In addition, the predicted lift-off length also corresponds to a power-law scaling of Siebers et al. (C) 2009 Elsevier Ltd. All rights reserved.