Patent ID: 8745969

Claim:
Apparatus for reducing NOx emissions in a powertrain comprising an internal combustion engine including a combustion chamber, the apparatus comprising: an aftertreatment system; and an aftertreatment system control module configured to: monitor an actual exhaust gas feedstream ratio of NO 2 to NO; monitor a desired exhaust gas feedstream ratio of NO 2 to NO; compare the actual and the desired exhaust gas feedstream ratios of NO 2 to NO; initiate NO 2 generation selectively to increase the actual exhaust gas feedstream ratio of NO 2 to NO by injecting a fuel mass into the combustion chamber after a primary combustion event to generate HO2, wherein said generated HO 2 oxidizes NO present in the combustion chamber to generate NO 2 sufficient to increase the actual exhaust gas feedstream ratio of NO 2 to NO at the desired exhaust gas feedstream ratio of NO 2 to NO.