A novel NH3 slip control for diesel engine selective catalytic reduction aftertreatment system

Abstract

To meet the future emission legislations, selective catalytic reduction aftertreatment system becomes a leading aftertreatment technique for heavy-duty diesel engines. In this article, a two-cell selective catalytic reduction model is first calibrated and verified on an experimental test bench. In order to regulate the ammonia coverage ratio in a proper range, an ammonia storage control is proposed based on the selective catalytic reduction model. The problem of NH3 slip during temperature rise is discussed and a corresponding perturbation injection control is proposed to buffer the sudden change in selective catalytic reduction ammonia storage capability. The NH3 slip control performance of the proposed strategy is experimentally validated in European Transient Cycle.