Modeling of Nitric Oxide and Soot Formation in Diesel Engine Combustion

A two-zone model was developed to describe the NO and soot formation in diesel engines. Nitric oxide formation is computed with the extended Zeldovich mechanism. The kinetic rate constants referring to the soot formation process are transferred from known investigation results of stationary flames to the diesel engine combustion. Adjustment between calculation and measurement is achieved by preset profiles for the local air/fuel ratios.

The results of computation are verified with experimental investigations using a fast gas-sampling valve and an optical measurement technique. The simulation model is able to approximate the measured NO and soot concentrations during combustion. Thus, the fundamental influences of different engine operating parameters on pollutant formation can be explained.