In the presented study, the aim is to develop a complete cycle model and to prepare a computer code for determining complete cycle, performance characteristics, and exhaust emissions of diesel engines. For this purpose, a computer program has been developed. To compute diesel engine cycles, zero-dimensional intake and exhaust model developed by Durgun, zero-dimensional compression and expansion model given by Heywood and quasi-dimensional phenomenological combustion model developed by Shahed and Ottikutti have been used and developed with new assumptions. The combustion model is based on a multi-zone combustion modeling concept. Details of fuel spray formation, fuel-air mixing, swirl and heat transfer have been taken into account in this model. Also, an emission model based on the chemical equilibrium and kinetics of NO has been developed to calculate the pollutant concentrations within each zone and the whole of the cylinder. Using the developed computer program, complete engine cycle, engine performance parameters and exhaust emissions can be determined easily. The values of the cylinder pressure and engine performance parameters predicted by the practically for various parameetric and alternative fuel studies. (C) 2008 Elsevier Ltd. All rights reserved.