Patent ID: 8562924

Claim:
A method of treating exhaust from an engine, the exhaust containing NOx, the NOx comprising at least nitrogen monoxide (NO), comprising: providing an exhaust aftertreatment system having at least the following devices arranged in the following order on an exhaust line: a catalyzed particulate filter and a selective reduction catalyst (SCR); wherein the catalyzed particulate filter receives engine-out exhaust having a first NO/NOx ratio and emits exhaust having a second NO/NOx ratio; bypassing a portion of the engine-out exhaust around the catalyzed particulate filter; reintroducing the bypassed portion of exhaust to the exhaust stream upstream the SCR device; wherein the bypassed portion of exhaust mixes with the exhaust from the catalyzed articulate filter to provide exhaust having a third NO/NOx ratio greater than the second NO/NOx ratio.