Development of a Quasi-Steady Approach Based Simulation Tool for System-Level Exhaust Aftertreatment Modelling

摘要

This article describes a system-level 1D simulation tool that has been constructed on the Quasi-Steady (QS) method. By assuming that spatial changes are much greater than the temporal ones, rigorous 1D governing equations can be considerably simplified thus becoming less computationally demanding to solve and therefore suitable for control-oriented modelling purposes. With the proposed tool exhaust pipe wall temperature profiles, including multiple-wall-layer configurations, are solved through a finite difference scheme. Momentum equation is included for predicting pressure losses due to frictions and geometric irregularity. Exhaust fluid properties (transport and thermodynamic) are evaluated according to NASA or JANAF polynomial thermal data basis. The proposed tool allows the consideration of an arbitrary number of chemical species and reactions in the entire system. A novel semi-automatic approach was developed to handle catalytic reaction kinetics intuitively. Global reaction mechanisms and their rate formulations can be input or modified via a GUI system and, without any compiling requirements to generate a new executive command, are ready to use.