A Phenomenological Model for Accurate and Time Efficient Prediction of Heat Release and Exhaust Emissions in Direct-Injection Diesel Engines

A phenomenological multi-zone model for prediction of heat release and exhaust emissions in DI Diesel engines is developed in an attempt to diminish the common trade-off between model accuracy and computing efficiency. This task is achieved by uncoupling the kinetic emission models from the detailed calculations of spray formation and heat release, which allows to substantially reduce the number of zones in that the kinetics of NO_x- and soot-formation have to be solved.

The predicted results of the model are compared with experimental data obtained from a turbo-charged, high-speed Diesel engine. The results for heat release and pressure histories as well as the estimated nitric oxide emissions are in good agreement with the test data, indicating that an appropriate simplification of the complex combustion process has been established. The soot model is capable of predicting trends, but there are further improvements necessary in order to produce quantitatively correct results.