Control-oriented modeling of a three-way catalytic converter with observation of the relative oxygen level profile

► Control-oriented, first-principle model of a TWC. ► On-line calculation of the relative oxygen level profile of a TWC. ► New identification method for control-oriented TWC models. ► Explanation of the asymmetric filling and depleting behavior of a TWC. ► On-line depletion strategy for TWCs after fuel cut-off phases.