Book Description
The combination of superior fuel economy and durability has made compression ignition direct injection diesel engines popular worldwide. However, these engines can emit large amounts of ozone-forming pollutants and particulates and so are being subjected to increasingly stringent regulations that require continual improvements in the combustion process. Further, improved engine power density is necessary at high load conditions, before the CIDI engine can be considered a contender in the next generation automotive engine technology. Understanding the physics and chemistry involved in diesel combustion, with its transient effects and the inhomogeneity of spray combustion is quite challenging. Great insight into the physics of the problem can be obtained when an in-cylinder computational analysis is used in conjunction with either an experimental program or through published experimental data. The main area to be investigated to obtain good combustion begins by defining the fuel injection process and the mean diameter of the fuel particle, injection pressure, drag coefficient, rate shaping, etc., correctly. This work presents a methodology to perform the task set out in the previous paragraph and uses experimental data obtained from available literature to construct a numerical model. A modified version of a multidimensional computer code called KIVA3V was used for the computations, with improved sub-models for mean droplet diameter, injection pressure and drop distortion and drag. The results achieved show good agreement with the published experimental data. It has been of special importance to model the spray distribution accurately, as the combustion process and the resulting pollutant emission formation is intimately tied to the in-cylinder fuel distribution. The present scheme has achieved excellent results in these aspects and will make an important contribution to the numerical simulation of the combustion process and pollutant emission formation in compression ignition direct injection engines.