Cummins Ip, Inc.

Joe V Hill

John N Chi

Phanindra V Garimella

Joan M Wills

Weiwen Wang

Lisa Farrell

Timothy R Frazier

Abdul R Ofoli

Aleksey Yezerets

Neal W Currier

Hasan Mohammed

Andy Osburn

According to one representative embodiment, an apparatus for controlling reductant dosing in an SCR catalyst system having a reductant injection system configured to inject reductant into an exhaust gas stream includes a controller, an actual reductant dosing rate module, and a reductant doser compensation module. The controller is configured to determine a reductant dosing rate command representing a desired reductant dosing rate. The actual reductant dosing rate module is configured to determine a predicted actual reductant dosing rate based at least partially on the reductant dosing rate command. The reductant doser compensation module is configured to determine a modified reductant dosing rate command based at least partially on the predicted actual reductant dosing rate. The reductant injection system injects reductant into the exhaust gas stream at a rate corresponding to the modified reductant dosing rate command.

Apparatus, system, and method for controlling reductant dosing in an SCR catalyst system

Various embodiments of an apparatus, system, and method are disclosed for controlling NOconversion in a selective catalytic reduction (SCR) system. According to one representative embodiment, an apparatus includes a duty cycle factor module and a NOconversion mode selection module. The duty cycle factor module is configured to determine a duty cycle factor of an internal combustion engine where the duty cycle factor represents predicted driving conditions of a vehicle in which the internal combustion engine is housed. The NOconversion mode selection module is configured to command NOconversion in the SCR system according to a first NOconversion mode if the duty cycle factor is within a duty cycle factor range and according to a second NOconversion mode if the duty cycle factor is not within the duty cycle factor range.

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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.

For example, according to one representative embodiment, an apparatus for reducing NOemissions in an engine exhaust includes a NOreduction target module configured to determine a NOreduction requirement. The apparatus also includes a tailpipe NOmodule configured to determine a sensed amount of NOexiting the engine system and a signal correction algorithm module configured to determine a corrected amount of NOexiting the engine system based at least partially on the sensed amount of NOexiting the engine system. The apparatus also includes a feedback ammonia target module configured to determine a feedback ammonia addition requirement. The feedback ammonia addition requirement includes an amount of ammonia added to the exhaust gas stream to achieve the NOreduction requirement in response to the corrected amount of NOexiting the engine system. The apparatus also includes a reductant target module that is configured to determine a reductant injection requirement.

Apparatus, system, and method for NOx signal correction in feedback controls of an SCR system

Various embodiments of an apparatus, system, and method are disclosed for reducing NOemissions on an SCR catalyst. For example, according to one representative embodiment, an apparatus for reducing NOemissions in an engine exhaust includes a NOreduction target module that is configured to determine a NOreduction requirement that includes an amount of NOin the exhaust gas stream to be reduced on a selective catalytic reduction (SCR) catalyst. The apparatus also includes an ammonia target module that is configured to determine an ammonia addition requirement that includes an amount of ammonia added to the exhaust gas stream to achieve the NOreduction requirement. The apparatus also includes a reductant target module that is configured to determine a reductant injection requirement that includes an amount of reductant added to the exhaust gas stream to achieve the ammonia addition requirement. The apparatus further includes a reductant limiting module that is configured to determine whether at least one reductant limiting condition is met and to limit the amount of reductant added in response to the at least one reductant limiting condition if the at least one reductant limiting condition has been met.

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Middlesbrough, United Kingdom

Joe V Hill