Advanced modeling and control of a three-way catalytic converter

Though often neglected, dynamic behavior of the three-way catalytic converter has a strong impact on the performance of the exhaust gas after-treatment system in spark ignition (SI) engine vehicles. A novel model-based control system has been created on the basis of a rigorous, kinetic model of the catalytic converter to obtain lower exhaust emission under dynamic operationg conditions. The knowledge obtained from the rigorous model has been used to create a dedicated control-oriented model, which serves as inferential sensor. The model is also used to calculate the control actions for the model predictive controller in an off-line procedure which are then used to tune an analytic controller that can run in the on-board computer. In that way, the known process nonliniearities are fully exploited by the controller to obtain a better performance of the system.