Method and apparatus for using dual parallel NOx traps for diesel emissions reduction

[0019]Referring to FIG. 1, a prior art dual trap emissions adsorber system 10 for controlling exhaust emissions 12 from an internal combustion engine 14 comprises a first catalytic NOx trap 16a and a second catalytic NOx trap 16b supplied with exhaust emissions 12 via a four-port valve 18. Traps 16a,16b are connected to first and second opposite ports 20a,20b of valve 18, respectively, and engine 14 and reductant 22 are connected to third and fourth opposite ports 20c,20d, respectively. As shown in FIG. 1, valve 18 is positioned to deliver emissions through first trap 16a for storage of NOx to yield a cleaned exhaust 24, and reductant 22 through second trap 16b simultaneously for regeneration thereof. Typically, reductant 22 is hydrocarbon reformate supplied from a source, not shown. When the valve core is rotated 90° in either direction, it will be seen that emissions 12 now flow to second trap 16b for NOx storage to yield cleaned exhaust 24, and reformate 22 flows to first trap 16a f