Method, Apparatus, and System To Control Selective Catalytic Reduction (SCR) Catalyst Ammonia Slip During High Temperature Transitions

Abstract

Method, apparatus, and system to control ammonia slip in a selective catalytic reduction (SCR) system. The method includes detecting an engine operation transition event, increasing NOx to the SCR catalyst, and decreasing a reductant dose. The system includes a controller to receive an engine transition signal, anticipate a temperature transition at the SCR catalyst in response to the engine transition signal, and cause a NOx increase in the exhaust gas stream to the SCR catalyst and a decrease of reductant to the SCR catalyst coinciding with the temperature transition at the SCR catalyst. The apparatus includes a NOx increase module to cause the NOx increase in the exhaust gas stream to the SCR catalyst in response to the engine transition signal. The apparatus also includes a reductant shut-off module configured to cause the reductant addition to the exhaust gas stream to turn off in response to the engine transition signal.

Dependencies are inferred from the claim text.