摘要:
Various embodiments of an apparatus, system, and method are disclosed for controlling NOx conversion in a selective catalytic reduction (SCR) system. According to one representative embodiment, an apparatus includes a duty cycle factor module and a NOx conversion 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 NOx conversion mode selection module is configured to command NOx conversion in the SCR system according to a first NOx conversion mode if the duty cycle factor is within a duty cycle factor range and according to a second NOx conversion mode if the duty cycle factor is not within the duty cycle factor range.
摘要:
Various embodiments of an apparatus, system, and method are disclosed for controlling NOx conversion in a selective catalytic reduction (SCR) system. According to one representative embodiment, an apparatus includes a duty cycle factor module and a NOx conversion 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 NOx conversion mode selection module is configured to command NOx conversion in the SCR system according to a first NOx conversion mode if the duty cycle factor is within a duty cycle factor range and according to a second NOx conversion mode if the duty cycle factor is not within the duty cycle factor range.
摘要:
According to one representative embodiment, an apparatus for reducing NOx emissions 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 NOx reduction target module and a reductant module. The NOx reduction target module is configured to determine a NOx reduction requirement, which includes an amount of NOx in 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 NOx reduction 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.
摘要:
According to one representative embodiment, an apparatus for reducing NOx emissions 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 NOx reduction target module and a reductant module. The NOx reduction target module is configured to determine a NOx reduction requirement, which includes an amount of NOx in 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 NOx reduction 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.
摘要:
Various embodiments of an apparatus, system, and method are disclosed for reducing NOx emissions on an SCR catalyst. For example, according to one representative embodiment, an apparatus for reducing NOx emissions in an engine exhaust includes a NOx reduction target module that is configured to determine a NOx reduction requirement that includes an amount of NOx in 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 NOx reduction 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.
摘要:
Various embodiments of an apparatus, system, and method are disclosed for reducing NOx emissions on an SCR catalyst. For example, according to one representative embodiment, an apparatus for reducing NOx emissions in an engine exhaust includes a NOx reduction target module that is configured to determine a NOx reduction requirement that includes an amount of NOx in 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 NOx reduction 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.
摘要:
Various embodiments of an apparatus, system, and method are disclosed for reducing NOx emissions using ammonia storage on an SCR catalyst. For example, according to one representative embodiment, an apparatus for reducing NOx emissions in an engine exhaust includes a NOx reduction target module that is configured to determine a NOx reduction requirement. The apparatus also includes an ammonia storage module that is configured to determine an ammonia storage modifier. An ammonia target module of the apparatus is configured to determine an ammonia addition requirement. The ammonia target module is communicable in data receiving communication with the ammonia storage module to receive the ammonia storage modifier, which is added to the ammonia addition 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.
摘要:
Various embodiments of an apparatus, system, and method are disclosed for reducing NOx emissions using ammonia storage on an SCR catalyst. For example, according to one representative embodiment, an apparatus for reducing NOx emissions in an engine exhaust includes a NOx reduction target module that is configured to determine a NOx reduction requirement. The apparatus also includes an ammonia storage module that is configured to determine an ammonia storage modifier. An ammonia target module of the apparatus is configured to determine an ammonia addition requirement. The ammonia target module is communicable in data receiving communication with the ammonia storage module to receive the ammonia storage modifier, which is added to the ammonia addition 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.
摘要:
According to one representative embodiment, an apparatus for determining the degradation of a selective catalytic reduction (SCR) catalyst of an engine exhaust aftertreatment system includes a system properties module configured to store at least one system dynamics property value of the exhaust system at a first time and receive the at least one system dynamics property value of the exhaust aftertreatment system at a second time subsequent to the first time. The apparatus also includes a system dynamics module configured to determine a storage capacity of the SCR catalyst based on a comparison between the at least one system dynamic property value at the first time and the at least one system dynamic property value at the second time. Additionally, the apparatus includes an SCR catalyst degradation factor module configured to determine an SCR catalyst degradation factor based at least partially on the storage capacity of the SCR catalyst.
摘要:
According to one exemplary embodiment, an apparatus is disclosed for estimating an NOx conversion efficiency of an SCR catalyst. The apparatus includes a catalyst degradation module for determining an SCR catalyst degradation factor and a NOx concentration module for determining an SCR catalyst inlet NOx concentration based on an interpretation of at least one NOx detector signal. Additionally, the apparatus includes an NH3 concentration module for determining an SCR catalyst inlet NH3 concentration, 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 NOx conversion efficiency module calculates a NOx conversion efficiency value based at least partially on the SCR catalyst degradation factor, the SCR catalyst inlet NOx concentration, the SCR catalyst inlet NH3 concentration, the exhaust gas SV, and the SCR catalyst bed temperature.