Abstract: Technical solutions described herein include an emissions control system for treating exhaust gas in a motor vehicle including an internal combustion engine. The emissions control system includes a model-based controller to control reductant injections into the exhaust gas. Controlling the reductant injections includes determining an amount of NOx and an amount of NH3 at an outlet of the first SCR device, and at an outlet of the second SCR device. The controlling further includes computing an amount of reductants to inject to maintain a first predetermined ratio between the amount of NH3 and the amount of NOx at the outlet of the first SCR device and to maintain a second predetermined ratio between the amount of NH3 and the amount of NOx at the outlet of the second SCR device. Further, the controlling includes sending a command for receipt by the reductant injectors to inject the computed amount of reductants.

Abstract: Technical solutions described herein include an emissions control system for treating exhaust gas in a motor vehicle including an internal combustion engine. The emissions control system includes a model-based controller to control reductant injections into the exhaust gas. Controlling the reductant injections includes determining an amount of NOx and an amount of NH3 at an outlet of the first SCR device, and at an outlet of the second SCR device. The controlling further includes computing an amount of reductants to inject to maintain a first predetermined ratio between the amount of NH3 and the amount of NOx at the outlet of the first SCR device and to maintain a second predetermined ratio between the amount of NH3 and the amount of NOx at the outlet of the second SCR device. Further, the controlling includes sending a command for receipt by the reductant injectors to inject the computed amount of reductants.

Abstract: An exhaust gas after-treatment system for an internal combustion engine includes a selective catalyst reduction on filter (SCRF) exhaust gas after-treatment device in communication with exhaust gases from the internal combustion engine and having treated exhaust gas output. An oxides of nitrogen (NOx) sensor is coupled to treated exhaust gases and has a NOx sensor output signal that is NOx and ammonia (NH3) cross-sensitive. A closed loop observer (CLO) is operatively coupled to receive the NOx sensor output signal and provides a NOx concentration signal to an electronic control unit operatively associated with the exhaust gas after-treatment system and the internal combustion engine. CLO output at least includes an exhaust gas NOx concentration estimate and the ECU is arranged to be operable upon the NOx concentration estimate to control exhaust gas after-treatment system and internal combustion engine to effect an overall reduction in actual NOx concentration with the exhaust gases.

Abstract: Technical solutions described herein include an emissions control system for treating exhaust gas in a motor vehicle including an internal combustion engine. The emissions control system includes a model-based controller to control reductant injection into the exhaust gas. Controlling the reductant injection includes determining an amount of NOx and an amount of NH3 at an outlet of the first SCR device, and at an outlet of the second SCR device. The controlling further includes computing an amount of reductant to inject to maintain a first predetermined ratio between the amount of NH3 and the amount of NOx at the outlet of the first SCR device and to maintain a second predetermined ratio between the amount of NH3 and the amount of NOx at the outlet of the second SCR device. Further, the controlling includes sending a command for receipt by the reductant injector to inject the computed amount of reductant.

Abstract: Technical solutions are described for selective catalytic reduction diagnosis in an emissions control system or an exhaust system used for treating exhaust gas, such as in a motor vehicle including an internal combustion engine. An example emissions control system includes a selective catalytic reduction (SCR) device. The emissions control system further includes a controller that is performs SCR fault diagnosis. The SCR fault diagnosis includes computing a plurality of estimated NH3 storage capacity values (?) of an SCR catalyst of the SCR device. The diagnosis further includes determining a diagnostic parameter of the SCR device using the plurality of estimated NH3 storage capacity values.

Abstract: Technical solutions are described for selective catalytic reduction diagnosis in an emissions control system or an exhaust system used for treating exhaust gas, such as in a motor vehicle including an internal combustion engine. An example emissions control system includes a selective catalytic reduction (SCR) device. The emissions control system further includes a controller that is performs SCR fault diagnosis. The SCR fault diagnosis includes computing a plurality of estimated NH3 storage capacity values (?) of an SCR catalyst of the SCR device. The diagnosis further includes determining a diagnostic parameter of the SCR device using the plurality of estimated NH3 storage capacity values.

Abstract: A method, control system, and vehicle system configured to control a selective catalyst reduction (SCR) system subtracts an amount of NOx present in a tailpipe upstream of the SCR system from an amount of NOx present in the tailpipe downstream of the SCR injector. A cumulative difference may be determined based on integrating the subtracted NOx value. The method, control system, and vehicle system are configured to determine whether the cumulative difference exceeds a control threshold, and to set a selected upstream NOx value as a predetermined model upstream NOx amount if the cumulative difference exceeds the control threshold, but to set the selected upstream NOx value as the determined upstream NOx amount if the cumulative difference does not exceed the control threshold. Thus, the system is reset to the model when downstream NOx values exceed upstream NOx values above a threshold, to bring the system back within control.

Abstract: A method, control system, and vehicle system configured to control a selective catalyst reduction (SCR) system subtracts an amount of NOx present in a tailpipe upstream of the SCR system from an amount of NOx present in the tailpipe downstream of the SCR injector. A cumulative difference may be determined based on integrating the subtracted NOx value. The method, control system, and vehicle system are configured to determine whether the cumulative difference exceeds a control threshold, and to set a selected upstream NOx value as a predetermined model upstream NOx amount if the cumulative difference exceeds the control threshold, but to set the selected upstream NOx value as the determined upstream NOx amount if the cumulative difference does not exceed the control threshold. Thus, the system is reset to the model when downstream NOx values exceed upstream NOx values above a threshold, to bring the system back within control.