Measurements and modeling of ozone enhanced compression ignition in a rapid compression machine and optically-accessible engine

For the present study, an ultraviolet light absorption diagnostic was used to measure O3 concentration during the compression stroke of a rapid compression machine and an optically-accessible research engine. Charge oxygen concentration, initial temperature, and equivalence ratio were varied; neat iso-octane was used for fueled experiments. Measurements were compared to single-zone chemical kinetic simulation results. Rapid thermally induced O3 decomposition was observed near top dead center. Ozone decomposition advanced when the charge temperature was increased, oxygen concentration was reduced, or fuel was added. While the model well-captures the experimental trends, for unfueled conditions the temporal prediction of O3 decomposition is generally too far retarded.