DI Diesel Performance and Emissions Models

Abstract

Public Reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Development of models for direct injection diesel performance and emissions of NO x and soot are the goals of this research. The simplest models investigated are flame temperature correlations. These correlations are semi-empirical tools that provide insight into the effects of dilution on NO x , particulate, and HC emissions and can be used by the design or calibration engineer to reduce the number of engine tests required. A characteristic time model for NO x emissions has been used to study the mixing processes in diesel engines and extended to study multiple injections, water/steam dilution, and the results of NO injection tests. This NO x model was also modified to calculate the NO formed in the cylinder as a function of time and was shown to correlate engine-out NO x emissions for four diesel engines. Development of a cycle simulation code is also underway. Primary emphasis has been placed on the study of the ignition and combustion submodels for this code. The NO x model mentioned above has been included in the code and a soot submodel proposed. Upon completion, the cycle simulation code will allow evaluation of new schemes for improving performance, power density, and pollutant emissions.