Patent ID: 7810316

Claim:
An apparatus for enhancing the efficiency of an exhaust aftertreatment system, the apparatus comprising: an intake module configured to receive a fluid stream; a bypass valve configured to direct a first fraction of the fluid stream to a first flowpath having a diesel oxidation catalyst (DOC) positioned therein, wherein the first fraction comprises an amount between zero and one hundred percent inclusive of the fluid stream; the bypass valve further configured to direct a second fraction of the fluid stream to a second flowpath to bypass the DOC; a controller comprising: a sensing module configured to interpret at least one operating condition; a target selection module configured to interpret operating criteria for each of at least one target component, the at least one target component comprising a selective catalytic reduction (SCR) component in fluid receiving communication with the fluid stream downstream of the bypass valve and the operating criteria comprising a desired NO x to N 2 conversion efficiency of the SCR component; a conditioning performance module configured to interpret performance criteria for each of at least one conditioning component, the at least one conditioning component comprising the DOC and the performance criteria comprising a DOC outlet NO 2 /NO x mole ratio; a fraction determination module configured to determine a first fraction target based at least partially on the at least one operating condition, the desired NO x to N 2 conversion efficiency, and the DOC outlet NO 2 /NO x mole ratio; and a valve position module configured to manipulate the bypass valve position based on the first fraction target to achieve an SCR inlet NO 2 /NO x mole ratio corresponding with the desired NO x to N 2 conversion efficiency.