In this investigation computational methods for the atomization process of a liquid fuel jet and the secondary breakup of droplets have been developed and tested for non-evaporating, solid-cone diesel fuel sprays injected into a cylindrical constant-volume cell using a KIVA-3 based code. The breakup of the liquid fuel is computed based on the Taylor analogy breakup model. In this new approach the droplet breakup process has been improved to account for the different breakup regimes which occur in diesel engine environments. In addition, an appropriate choice of the initial drop deformation parameters allows the simulation of a fragmented liquid core at the nozzle exit.The model enhancements have been tested by comparisons with data from phase doppler anemometry. Specifically, the droplet radius and velocity distributions have been compared over two cross-sections in the near-field region of the spray. Additional comparisons have been conducted with data computed by means of the wave breakup model of Reitz and with corresponding experimental results of Hiroyasu and Kadota. The indicated model improvements agree well with these data for the global spray behavior like penetration, radial expansion and cross-sectional drop size distributions.