Multi-zone thermodynamic modeling of combustion and emission formation in CNG engines using detailed chemical kinetics

The model results, based on detailed chemistry simulation, have been found to be in good agreement with experimental data for all the species at engine exhaust, and a higher prediction capability than that obtained through simplified reaction and chemical equilibrium methods has been shown. The influences of the uncertainties in RAFRs and unburned mass fractions on the calculated results are discussed. The unburned gas fraction, derived from the calculated and measured oxygen concentration at the engine exhaust, has been shown to be a way of correcting the hydrocarbon emissions.