IN-CYLINDER NOx HISTORIES IN AN INDIRECT INJECTION DIESEL ENGINE: COMPARISON BETWEEN EXPERIMENTAL DATA AND MODEL PREDICTIONS.

NOx concentrations within the cylinder of an operating single-cylinder version of a passenger-car type, indirect-injection diesel engine have been measured using a total cylinder sampling system. Measurements have been made for 11 different operating conditions. Engine speeds of 1000 and 1500 rpm and the load range corresponding to equivalence ratios ranging from 0. 32 to 0. 94 were explored. The influences of fuel injection timing and exhaust recirculation were also examined. The experimental data were compared with model predictions made using MIT's stochastic combustion model for this engine. In general, the modeled results were in good agreement with the experimental results. The major difference was that the model did not predict the measured higher NOx concentrations in the cylinder than in the exhaust.