Patent ID: 7152396
Filing Date: 2006-12-26
Classification: F01N,Y02T

Abstract:
1. A reductant distributor for placement in a stream of lean NOx exhaust flowing through a lean NOx trap, the NOx trap having an inlet face comprising openings of longitudinal cells for through-flow of lean NOx exhaust, the cells having cell walls carrying absorbent material for trapping NOx from lean NOx exhaust and for releasing NOx in the presence of a reducing atmosphere for trapped NOx; the reductant distributor comprising: a reductant gas conduit, a reductant gas distributor with an outlet, and a mechanism for progressive positioning of the outlet of the reductant gas distributor at portions of the inlet face of the lean NOx trap; the reductant gas conduit having an inlet for receiving reductant gas under gas flow pressure and transporting it to the reductant gas distributor, the reductant gas distributor having an inlet for reductant gas from the reductant gas conduit and a distributor outlet shaped to release the reductant gas at a predetermined sector portion of the inlet face of the lean NOx trap while deflecting the lean NOx exhaust stream to other portions of the inlet face, the reductant gas distributor being shaped for divergent flow of the reductant gas from the inlet to the distributor outlet to release the reductant gas in a flow path aligned with the longitudinal cells of the NOx trap, the reductant gas distributor including an internal deflector in the flow path for directing divergent reductant gas flow from the inlet to the outlet, and the positioning mechanism being operative for progressive relative movement between the distributor outlet and sector portions of the inlet face of the lean NOx trap for reduction of trapped NOx in a sector while lean NOx exhaust is flowing through cells of the trap not receiving reductant gas from the distributor.