Experimental and Theoretical Study of Nitric Oxide Formation in Internal Combustion Engines

Abstract

The nonequilibrium formation of nitric oxide within the internal combustion engine cylinder is examined. A thermodynamic model which predicts the properties of the burnt and unburnt gases during the combustion process is developed. A set of reactions which govern the formation of nitric oxide is proposed, and rate equations for nitric oxide concentrations as a function of time in the post-flame gases are derived. The results of time-resolved measurements carried out on a CFR engine are described, where emitted light intensities at wavelengths selected to record radiation from the CO + O and NO + O continua were used to determine the nitric oxide concentration. The comparison between theoretical and experimental results for fuel-lean mixtures confirms that the important features of the model presented are correct.