Adaptive control of a three-way catalytic converter

Abstract

The three-way catalytic converter (TWC) is an effective device for reducing exhaust emissions in automobiles. For control purposes, the TWC can be regarded as an oxygen storage device. In order to reduce exhaust emissions efficiently, the oxygen storage should neither be completely full nor totally empty. Based on a simple model for oxygen storage in the TWC, an adaptive scheme for the control of the oxygen level is presented. The parameters involved in the model for oxygen storage are identified online by measuring the air-to-fuel ratios upstream and downstream of the TWC and using a recursive Gauss-Newton estimation method.