Persistent Memory Effects and Pre-Conditioning For Repeatable Investigations Into Three-Way Catalyst Dynamics

This paper presents the results of an experimental study into the dynamic behaviour of a three-way automotive catalyst. The study suggests that the dynamic response of the catalyst can be significantly affected by a persistent memory effect in addition to the familiar oxygen storage / release dynamics of the system. In particular, the effects of prior rich or stoichiometric operation are shown to persist even after extended periods of lean operation. This memory effect is important, not only because of its potential impact on conversion efficiency, but also because of its impact on the repeatability of experiments carried out under what would appear to be similar operating conditions.