Technical Paper
Model for Prediction of Incylinder and Exhaust Soot Emissions from Direct Injection Diesel Engines
1988-09-01
881251
A detailed soot emission model for Direct Injection diesel engines has been developed. The model can predict both in-cylinder and exhaust soot concentrations from the engines. Accurate predictions of flame temperature, equivalence ratio and engine cylinder pressure are made for the soot model using a two-dimensional, multi-zone, phenomenological spray mixing combustion model. The net soot concentration in diesel exhaust results from the soot formation and oxidation processes in the combustion chamber. Both these processes occur within the turbulent eddy structure of the charge. Soot formation occurs in the large scale eddy structure in two stages - radical nuclei formation and the formation of the soot particulates from these nuclei. In the fuel rich spray elements, soot is considered to form in both the burning zone and the surrounding fluids. The oxidation or combustion rate of nuclei and soot particulates is kinetically controlled and takes place in the fine eddy structure.