Global reaction mechanism and kinetic parameters identification for a three-way catalyst model in a system simulation context

Sana  Loussaief, SIEMENS Digital Industries Software

Model-based development is a key enabler for the design of vehicles with well-controlled emissions as they are influenced by many subsystems and their interactions including the engine, the thermal management, the exhaust systems, the control.

However, the development of three-way catalytic converter models remains a challenge as soon as physical modeling approaches based on the description of a kinetic scheme are considered. The set-up of 0D/1D/nD models  is often a difficult task for powertrain engineers.

This is linked, to the required competency essentially handled by chemistry experts on one hand, and to the model calibration workflows which strongly depend on experimental data on the other hand.

Nevertheless, when it comes to the prediction of the tail-pipe emissions over various scenarios and/or vehicle configurations, describing the catalyst behaviour is of key importance and must fit with real observations.

This presentation introduces methodologies developed to address the issue of three-way catalytic converter model set-up with a step by step workflow illustrated  within Simcenter Amesim.

This tries to answer commonly raised questions and concerned with respect to modelling methodology: how to get the right data and parameters as inputs of the modelling work and how to handle cases where available test data are not enough to get these parameters.

The presented workflow includes an investigation of a globalized reaction mechanism consistent with experimental observations or washcoat composition.

The objective is to get a model with a minimal set of reactions as a pre-requisite to a time and cost-efficient calibration process associated with fast simulation times enabling system integration and controls evaluation, while keeping a reasonable model accuracy.