The results of modeling fluid dynamics, heat/mass transfer, and combustion processes in diesel engine like conditions are presented with a view to establishing the effects of droplet heating and evaporation models on the prediction of spray penetration, in-cylinder gas pressure, and the amount of fuel vapor, O-2, CO2, CO, and NO. The following models have been studied: the infinite thermal conductivity (ITC) and effective thermal conductivity (ETC) liquid phase models, the basic gas phase model, and the gas phase model suggested by Abramzon and Sirignano (1989). A modified version of the TAB (Taylor analogy breakup) model was used for modeling the droplet breakup process. It is pointed out that the ETC model leads to the prediction of shorter spray penetration, in agreement with experimental data, when compared with the ITC model. The effect of the liquid phase model on predicted gas pressure in diesel engines is shown to be relatively weak. The predicted amounts of fuel vapor, O-2, CO2, CO, and NO are strongly affected by the choice of the liquid phase model but practically unaffected by the choice of the gas phase model.