Indirect Adaptive Control of a Three-Way Catalyst

Based on an oxygen storage model of the three-way catalyst (TWC) an indirect adaptive control system is proposed. Utilizing a recursive Markov estimate method, the parameters involved in the model are identified on-line by measuring the upstream and downstream air-to-fuel ratios. These parameters are then used to estimate the relative oxygen level in the TWC which in turn is used as the control variable for the primary controller.