An automotive vehicle includes an internal combustion engine and an exhaust system. The exhaust treatment system includes a dosing system that injects NH.sub.3 into an exhaust gas stream generated by the engine. An SCR device stores an amount of the NH.sub.3 and converts NOx into diatomic nitrogen (N.sub.2) and water (H.sub.2O) based on the stored amount of the NH.sub.3. The vehicle further includes an SCR status estimator device and a controller. The SCR status estimator device determines an NH.sub.3 coverage ratio (R), which indicates a stored amount of NH.sub.3 with respect to a maximum NH.sub.3 storage capacity of the SCR device. The controller determines a target NOx reduction efficiency (.sub.NOx) of the SCR device, and an NH.sub.3 coverage ratio set point (R.sub.sp) based on the .sub.NOx. The controller also generates an NH.sub.3 control signal (u) that controls the dosing system based on a comparison between the R and the R.sub.sp.

A method for evaluating a sensor signal of an exhaust NOx sensor, which is disposed downstream of a three-way catalytic converter in an exhaust system of a spark ignition internal combustion engine. An ammonia factor is modeled downstream of the three-way catalytic converter using an ammonia formation model. A NOx emission is modeled in the exhaust system downstream of the three-way catalytic converter using a NOx model. The modeled ammonia emissions and the modeled NOx emission are separated by a separation algorithm using the sensor signal of the exhaust NOx sensor. The separation algorithm provides quantitative information about the tailpipe ammonia emissions and the tailpipe NOx emissions of the spark ignition internal combustion engine. An engine control unit and an internal combustion engine for carrying out such a method are also provided.

Disclosed are model predictive control (MPC) systems, methods for using such MPC systems, and motor vehicles with selective catalytic reduction (SCR) employing MPC control. An SCR-regulating MPC control system is disclosed that includes an NOx sensor for detecting nitrogen oxide (NOx) input received by the SCR system, catalyst NOx sensors for detecting NOx output for two SCR catalysts, and catalyst NH3 sensors for detecting ammonia (NH3) slip for each SCR catalyst. The MPC system also includes a control unit programmed to: receive desired can conversion efficiencies for the SCR catalysts; determine desired can NOx outputs for the SCR catalysts; determine maximum NH3 storage capacities for the SCR catalyst; calculate the current can conversion efficiency for each SCR catalyst; calculate an optimized reductant pulse-width and/or volume from the current can conversion efficiencies; and, command an SCR dosing injector to inject a reductant into an SCR conduit based on the calculated pulse-width/volume.

In a method for dynamic monitoring of gas sensors of an internal combustion engine, in the event of a change of the gas state variable to be measured, a dynamic diagnosis is carried out based on a comparison of a measured signal which is an actual value of an output signal of the gas sensor and a modeled signal which is a model value. The output signal of the gas sensor is filtered using a high-pass filter and higher-frequency signal components are analyzed.

Disclosed are model predictive control (MPC) systems, methods for using such MPC systems, and motor vehicles with selective catalytic reduction (SCR) employing MPC control. An SCR-regulating MPC control system is disclosed that includes an NOx sensor for detecting nitrogen oxide (NOx) input received by the SCR system, catalyst NOx sensors for detecting NOx output for two SCR catalysts, and catalyst NH3 sensors for detecting ammonia (NH3) slip for each SCR catalyst. The MPC system also includes a control unit programmed to: receive desired can conversion efficiencies for the SCR catalysts; determine desired can NOx outputs for the SCR catalysts; determine maximum NH3 storage capacities for the SCR catalyst; calculate the current can conversion efficiency for each SCR catalyst; calculate an optimized reductant pulse-width and/or volume from the current can conversion efficiencies; and, command an SCR dosing injector to inject a reductant into an SCR conduit based on the calculated pulse-width/volume.

Systems, methods and apparatus disclosed that include an internal combustion engine and an exhaust system that includes an exhaust aftertreatment system with an SCR catalyst. A NO.sub.x sensor downstream of the SCR catalyst is provided along with techniques for estimating an amount of NO.sub.x and NH3 at the tailpipe to decouple the impact of cross-sensitivity of the NO.sub.x sensor to NO.sub.x and NH3. Feedback control of the reductant dosing amount based on these estimates is also provided.

Disclosed are model predictive control (MPC) systems, methods for using such MPC systems, and motor vehicles with selective catalytic reduction (SCR) employing MPC control. An SCR-regulating MPC control system is disclosed that includes an NOx sensor for detecting nitrogen oxide (NOx) input received by the SCR system, catalyst NOx sensors for detecting NOx output for two SCR catalysts, and catalyst NH3 sensors for detecting ammonia (NH3) slip for each SCR catalyst. The MPC system also includes a control unit programmed to: receive desired can conversion efficiencies for the SCR catalysts; determine desired can NOx outputs for the SCR catalysts; determine maximum NH3 storage capacities for the SCR catalyst; calculate the current can conversion efficiency for each SCR catalyst; calculate an optimized reductant pulse-width and/or volume from the current can conversion efficiencies; and, command an SCR dosing injector to inject a reductant into an SCR conduit based on the calculated pulse-width/volume.

Embodiments described herein methods can be used in particulate filter regeneration, such as particulate filters used for filtering the exhaust of an engine, e.g., a diesel engine. Systems herein can be configured to dispense combustion gas(es) into housing were a particulate filter is contained and to ignite the combustion gases. Methods for conducting a safety verification process of such systems are disclosed, as well as methods for regenerating the filters. Still other embodiments are described.

In a method of operating an exhaust emission control device, the presence of an actual pressure loss of a particulate filter is determined, and a model pressure loss is determined as a function of a state variable. On the basis of the actual pressure loss and the model pressure loss a pressure quotient is determined and a condition of the particulate filter is ascertained in a diagnostic mode in response to the pressure quotient.

One exemplary embodiment is a method of operating a system comprising an internal combustion engine system, and an exhaust aftertreatment system comprising an SCR catalyst, and an electronic control system. The method comprises operating the electronic control system to perform the acts of determining a predicted temperature value indicative of a predicted future temperature of the SCR catalyst, determining a temperature profile value using the predicted temperature value and a current temperature value indicative of a current temperature of the SCR catalyst, operating a controller to provide an output indicating a difference between the temperature profile value and a temperature target, determining a heat request using the output of the controller, filtering the heat request using a prediction horizon, and controlling operation of the engine system using the filtered heat request to increase a temperature of the SCR catalyst.