Engine HC Emissions Modeling: Partial Burn Effects

Abstract

A comparison of predicted and experimental HC emissions at high rates of exhaust gas recirculation (EGR), indicates that partial burning is responsible for significant changes in HC emission trends under otherwise normal, non-misfiring engine operating conditions. Ion-probe experiments show a measurable fraction of engine cycles in which the flame did not completely propagate across the chamber whenever HC emissions were high. A simple semi-empirical model is proposed to predict HC emissions from partial burning based on measured burn rate parameters.