Prediction of carbon monoxide and hydrocarbon emissions in iso-octane HCCI engine combustion using multi-zone simulations

A novel detailed chemical kinetic model that incorporates information from a computational fluid mechanics code was developed to simulate homogeneous charge compression ignitions (HCCI) combustion. This model very accurately predicted many aspects of the HCCI combustion process. While overall this model exhibited very good predictive capability for HCCI combustion, previous simulations using this model underpredicted CO emissions by an order of magnitude. A factor in the under-prediction of CO may be that all previous simulations were conducted with 10 chemical kinetic zones. The chemistry that results in CO emissions was very sensitive to small changes in temperature within the engine. The number of zones, i.e., temperature resolution, in which it affects the model's prediction of hydrocarbon and CO emissions in an HCCI engine was studied. Simulations with 10, 20, and 40 chemical kinetic zones were conducted using a detailed chemical kinetic mechanism (859 species, 3606 reactions) to simulate an isooctane fueled HCCI engine. The 10-zones were adequate to resolve the hydrocarbon emissions, but a greater number of zones are required to resolve CO emissions. Original is an abstract.