| abstract |
A lean NOx trap operating in a lean NOx exhaust stream is progressively regenerated, sector to sector, for efficient operation of the trap and conservation of reducing gas used in the regeneration. A reductant gas distributor is inserted in the exhaust upstream of the trap. Reductant gas is carried into the exhaust duct through a conduit portion and the reductant gas stream diverged and directed through a distributor into selected cells of the trap. The NOx in the selected cells is reduced to N 2 while lean NOx exhaust continues to flow through the remainder of the trap. By relative movement of the reductant gas distributor and the trap, the entire trap is progressively and continually regenerated while still preforming as a NOx trap. |