Abstract: Internal combustion engine (ICE) exhaust gas treatment systems include the ICE having one or more cylinders configured to receive a mixture of air and fuel defined by an air to fuel ratio (AFR) for combustion therein, a control module configured to control the AFR, a diesel oxidation catalyst (DOC) configured to receive exhaust gas generated by the ICE and oxidize NOx species within the exhaust gas, and a selective catalytic reduction device (SCR) configured to receive exhaust gas from the DOC. Methods for operating and diagnosing such systems include determining, via the control module, a baseline value of a SCR performance parameter which is unsuitable, changing, via the control module, the AFR to change the DOC outlet NO2:NOx ratio, subsequently assessing a second value of the SCR performance parameter, and implementing a control action based on the second value of the SCR performance parameter.

Abstract: Internal combustion engine (ICE) exhaust gas treatment systems include the ICE having one or more cylinders configured to receive a mixture of air and fuel defined by an air to fuel ratio (AFR) for combustion therein, a control module configured to control the AFR, a diesel oxidation catalyst (DOC) configured to receive exhaust gas generated by the ICE and oxidize NOx species within the exhaust gas, and a selective catalytic reduction device (SCR) configured to receive exhaust gas from the DOC. Methods for operating and diagnosing such systems include determining, via the control module, a baseline value of a SCR performance parameter which is unsuitable, changing, via the control module, the AFR to change the DOC outlet NO2:NOx ratio, subsequently assessing a second value of the SCR performance parameter, and implementing a control action based on the second value of the SCR performance parameter.

Abstract: Technical solutions are described for an emissions control system for controlling a selective catalytic reduction (SCR) device of an exhaust system of an internal combustion engine. An example computer-implemented method includes governing a reductant dosing in the SCR device. For example, governing the dosing includes computing a reductant dosing rate based on a chemical model of the SCR device. Further, the governing includes determining a temperature modulation factor based on inlet temperature of exhaust gas input for the SCR. The method further includes adjusting the reductant dosing rate by scaling the reductant dosing rate by the temperature modulation factor. The method further includes causing an amount of reductant to be injected into an SCR catalyst according to the adjusted reductant dosing rate.

Abstract: Technical solutions are described for an emissions control system for controlling a selective catalytic reduction (SCR) device of an exhaust system of an internal combustion engine. An example computer-implemented method includes governing a reductant dosing in the SCR device. For example, governing the dosing includes computing a reductant dosing rate based on a chemical model of the SCR device. Further, the governing includes determining a temperature modulation factor based on inlet temperature of exhaust gas input for the SCR. The method further includes adjusting the reductant dosing rate by scaling the reductant dosing rate by the temperature modulation factor. The method further includes causing an amount of reductant to be injected into an SCR catalyst according to the adjusted reductant dosing rate.

Abstract: Disclosed are SCR predictive control systems, methods for using such control systems, and motor vehicles with SCR employing predictive control. A method for regulating operation of an SCR system includes receiving sensor signals indicative of NOx output downstream from an SCR catalyst, and sensor signals indicative of exhaust gas temperature upstream from the SCR catalyst. The method determines if a model error condition has occurred for the NOx output signal and, responsive to such an occurrence, modulating dosing injector output for at least a calibrated designated time period. Upon expiration of the designated time period, the dosing injector is activated and commanded to inject reductant in accordance with a modulated dosing value. After the dosing injector injects the modulated dosing value of reductant, the method determines if the SCR system is underdosing or overdosing based on a response shape of signals received from the outlet NOx content sensor.

Abstract: Disclosed are SCR predictive control systems, methods for using such control systems, and motor vehicles with SCR employing predictive control. A method for regulating operation of an SCR system includes receiving sensor signals indicative of NOx output downstream from an SCR catalyst, and sensor signals indicative of exhaust gas temperature upstream from the SCR catalyst. The method determines if a model error condition has occurred for the NOx output signal and, responsive to such an occurrence, modulating dosing injector output for at least a calibrated designated time period. Upon expiration of the designated time period, the dosing injector is activated and commanded to inject reductant in accordance with a modulated dosing value. After the dosing injector injects the modulated dosing value of reductant, the method determines if the SCR system is underdosing or overdosing based on a response shape of signals received from the outlet NOx content sensor.