Cummins IP, Inc.

Andy Osburn

Phanindra V Garimella

Joan M Wills

John N Chi

Aleksey Yezerets

Neal W Currier

Timothy R Frazier

Abdul R Ofoli

Weiwen Wang

Lisa Farrell

Joe V Hill

According to one representative embodiment, an apparatus for reducing NOemissions in an engine exhaust gas stream of an engine system having a selective catalytic reduction (SCR) system with an SCR catalyst positioned downstream of a reductant injector includes a NOreduction target module and a reductant module. The NOreduction target module is configured to determine a NOreduction requirement, which includes an amount of NOin the exhaust gas stream to be reduced on the SCR catalyst. The reductant module is configured to determine the amount of reductant added to the exhaust gas stream to achieve the NOreduction requirement. The amount of reductant added to the exhaust gas stream is a function of at least one ammonia storage characteristic of the SCR catalyst, at least one reductant-to-ammonia conversion characteristic, and a conversion capability of an AMOX catalyst in exhaust receiving communication with the SCR catalyst.

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According to one exemplary embodiment, an apparatus is disclosed for estimating an NOconversion efficiency of an SCR catalyst. The apparatus includes a catalyst degradation module for determining an SCR catalyst degradation factor and a NOconcentration module for determining an SCR catalyst inlet NOconcentration based on an interpretation of at least one NOdetector signal. Additionally, the apparatus includes an NHconcentration module for determining an SCR catalyst inlet NHconcentration, a temperature module for determining an SCR catalyst bed temperature of the at least one SCR catalyst, and a space velocity (SV) module for determining an exhaust gas SV for the SCR catalyst. A NOconversion efficiency module calculates a NOconversion efficiency value based at least partially on the SCR catalyst degradation factor, the SCR catalyst inlet NOconcentration, the SCR catalyst inlet NHconcentration, the exhaust gas SV, and the SCR catalyst bed temperature.

Apparatus, system, and method for estimating an NOx conversion efficiency of a selective catalytic reduction catalyst

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Nashville, IN, United States of America

Andy Osburn