Performance and Emission Predictions for a Multi-Cylinder Spark Ignition Engine

Abstract

A comparison is made of experimental results and predictions of performance and emissions from a multi-cylinder spark ignition engine over a range of air-fuel ratios and two throttle settings. The results showed that a simplified two zone combustion model, a seven reaction scheme for nitric oxide formation, a partial freezing model for carbon monoxide and the inclusion of chemical reactions and variable specific heat along the pathlines in the wave equations gave good agreement with the measurements at the common pipe junction and exhaust outlet, but due to cyclic dispersion and maldistribution of fuel between cylinders the predictions of the emissions in the exhaust manifold adjacent to the cylinder were not so good. The predicted air flow and indicated power agreed well with experiment.