METHODS FOR ENGINE EXHAUST NOX CONTROL USING NO OXIDATION IN THE ENGINE

摘要

A powertrain includes an internal combustion engine having a combustion chamber and an aftertreatment system. A method for reducing NOx emissions in the powertrain includes monitoring an actual exhaust gas feedstream ratio of NO2 to NO, monitoring a desired exhaust gas feedstream ratio of NO2 to NO, comparing the actual and the desired exhaust gas feedstream ratios of NO2 to NO, and selectively initiating a NO2 generation cycle based upon the comparison of the actual and the desired exhaust gas feedstream ratios of NO2 to NO comprising injecting fuel mass into the combustion chamber after a primary combustion event.