APPARATUS, SYSTEM, AND METHOD FOR REDUCING NOX EMISSIONS ON AN SCR CATALYST

摘要

According to one representative embodiment, an apparatus (130) for reducing NOx emissions in an engine exhaust includes a NOx reduction target module (300) operable to determine a NOx reduction requirement (304). The apparatus also includes an ammonia target module (310) operable to determine an ammonia addition requirement (326) that includes an amount of ammonia added to the exhaust gas stream to achieve the NOx reduction requirement. The apparatus also includes a reductant target module (330) that has a hydrolysis module (333) and an inverse hydrolysis module (334). The hydrolysis module is operable to determine a predicted amount of ammonia and isocyanic acid entering the SCR catalyst (343, 349). The inverse hydrolysis module is operable to determine a reductant injection requirement (332) based at least partially on the predicted amount of ammonia and isocyanic acid entering the SCR catalyst.