Modeling of the NOx trap and experimental validation using ultra-fast NOx analyzers

The present paper employs and validates a NOx trap model which attempts an optimum compromise between complexity and predictive accuracy. It is shown that using the same set of kinetic data, the model is able to predict the storage rates and the maximum storage amounts as function of temperature. Moreover, the model predicts with reasonable accuracy the NO breakthrough during rich-mode regeneration and the spontaneous/thermal NO2 release when the temperature is increased in a saturated catalyst. The experimental findings highlight the importance of transient O2 adsorption/desorption phenomena which are incorporated in the model. The use of ultra-fast responding NO/NOx analyzers was necessary for the study and modeling of the transient operation following inlet composition switches.