A one-dimensional model for heat release rate and emission formation in diesel engines based on correlations for entrainment rate,lift-off length and ignition delay: Validation for transient conditions

Abstract

A simplified one-dimensional model for combustion and emission formation in diesel engines has been developed in a project where the long-term objective is to predict the emissions during transient operation. The models are intended to be used as a tool for pre-development of after-treatment systems and for offline calibration of engine controls. These applications imply that the final model must be both computationally inexpensive and comprehensive. The model is based on a correlation for the air entrainment rate which is applied to a discretized injection event. On this, the combustion rate and the emission formation rate are imposed with simple models. In this publication, the model is validated for the targeted conditions and transient operation. The model is based on a previously presented model which was evaluated for steady state conditions. The model presented here has been modified to address the shortcomings that were identified in the previous evaluation. The model was able to predict the heat release rate and the emissions of nitrogen oxide (NO) and soot with reasonable accuracy and also the requirement regarding the computational time was met. The average time for simulation of one engine cycle was approximately 3 s on a standard laptop.

Keywords

Diesel combustion model emission model transient emissions

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