Abstract: Methods and systems include an operation to interpret a face-plugging index and/or a reduction in an expected oxidation efficiency of an oxidation catalyst disposed in an internal combustion engine aftertreatment system, and in response to the face-plugging index or the reduction oxidation efficiency reaching a threshold value, an operation to provide a catalyst element reversal command.

Abstract: A selective catalytic reduction (SCR) system includes a mixer that has a plurality of blades spaced about a central tube. The mixer can be configured to receive a reductant and exhaust gas mixture. The SCR system also includes a closed-end tube that is downstream of the mixer and configured to receive the reductant and exhaust gas mixture from the mixer. The closed-end tube includes a closed end opposing an open end. The closed end is substantially perpendicular to an exhaust flow direction. The closed-end tube further includes a sidewall that extends between the open and closed end. The sidewall can include a plurality of perforations. The flange plate of the SCR system includes an annular disk that has a plurality of openings through which reductant and exhaust gas mixture received from the closed-end tube is flowable. The flange plate is coupled to and supports in place the closed-end tube.