A controller for controlling operation of an aftertreatment system that is configured to treat constituents of an exhaust gas produced by an engine, the aftertreatment system including a selective catalytic reduction (SCR) catalyst, the controller configured to: generate a short-term cumulative degradation estimate of the SCR catalyst corresponding to reversible degradation of the SCR catalyst due to sulfur and/or hydrocarbons based on a SCR catalyst temperature parameter; generate a long-term cumulative degradation estimate of the SCR catalyst corresponding to thermal aging of the SCR catalyst based on the SCR catalyst temperature parameter; generate a combined degradation estimate of the SCR catalyst based on the short-term cumulative degradation estimate and the long-term cumulative degradation estimate; and adjust an amount of reductant and/or an amount of hydrocarbons inserted into the aftertreatment system based on the combined degradation estimate of the SCR catalyst.

A controller 1 includes a calculation unit 10 that receives the current sensor value A1 of the vehicle and calculates an injection amount based on the current sensor value A1 and a target value of the ammonia adsorption amount of the selective reduction catalyst 105 so that the ammonia adsorption amount approaches the target value, and a prediction unit 20 that receives the current sensor value B1 and calculates a corrected target value by future prediction based on the current sensor value B1. The calculation unit 10 calculates the injection amount based on the corrected target value calculated by the prediction unit 20.

A method for diagnosing a NOx sensor is provided. The method includes receiving data indicative of operating conditions of an engine or an aftertreatment system; determining, during a first period of time, that an amount of NOx output from the aftertreatment system satisfies a low NOx operating mode condition; determining, during a second period of time, that operating conditions for ammonia slip are present based on data regarding operation of the aftertreatment system; responsive to the determination that operating conditions for ammonia slip are present, determining that the amount of NOx output from the aftertreatment system satisfies a high NOx operating mode condition; comparing a difference between a minimum value from the first period of time and a maximum value from a second period of time to a diagnostic threshold; and responsive to the difference being less than the diagnostic threshold, setting an alert.

A method for ascertaining an exhaust gas composition of an exhaust gas of an internal combustion engine with regard to an ammonia fraction and a nitrogen oxides fraction in an exhaust gas system including an SCR catalytic converter. The method includes detecting, using a sensor, a first signal whose magnitude is a function of the nitrogen oxides fraction of the exhaust gas upstream from the SCR catalytic converter, detecting using a sensor a second signal whose magnitude is a function of the ammonia fraction and the nitrogen oxides fraction of the exhaust gas downstream from the SCR catalytic converter, storing the two signals over an observation period, and ascertaining the ammonia fraction and optionally the nitrogen oxides fraction of the exhaust gas downstream from the at least one SCR catalytic converter using a calculation rule that uses the two signals during the observation period as input variables.

Systems and methods for controlling a gasoline urea selective catalytic reductant catalyst are described. In one example, an observer is provided that corrects an estimate of an amount of NH.sub.3 that is stored in a SCR. The amount of NH.sub.3 that is stored in the SCR is a basis for generating additional NH.sub.3 or ceasing generation of NH.sub.3.

A controller for an aftertreatment system coupled to an engine is configured to: in response to receiving an engine shutdown signal, determine an estimated amount of ammonia stored on a selective catalytic reduction (SCR) catalyst included in the aftertreatment system; in response to determining that the estimated amount of ammonia stored in the SCR catalyst is less than an ammonia storage threshold, cause flow of a heated gas towards the SCR catalyst; cause insertion of reductant into an exhaust gas flowing through the aftertreatment system; and in response to determining that the estimated amount of ammonia stored in the SCR catalyst is equal to or greater than the ammonia storage threshold, cause shutdown of the engine.

Disclosed is a method for diagnosing a first exhaust treatment component for treatment of an exhaust gas stream comprising means for oxidizing nitric oxide into nitrogen dioxide. A first reduction catalytic converter is arranged upstream said means for oxidizing nitric oxide into nitrogen dioxide, and a second reduction catalytic converter is arranged downstream said means. A reagent is for reduction of nitrogen oxides in said first catalytic converter, and a first sensor measures an occurrence of nitrogen oxide downstream said means but upstream said second reduction catalytic converter. The method comprises: causing a supply of reagent upstream said first reduction catalytic converter to an extent exceeding the extent to which reagent is consumed by the first reduction catalytic converter, determining a first measure of the occurrence of reagent downstream said means for oxidizing, and diagnosing said means for oxidizing nitric oxide into nitrogen dioxide based on said first measure.

A computer implemented method for anomality detection at a first nitrogen oxide (NOx) sensor forming part of an exhaust gas aftertreatment system (EATS) is provided. The EATS is coupled downstream of an internal combustion engine (ICE). The disclosed methodology applies manipulation of the ICE for detecting such a possible anomality.

Embodiments are directed towards controlling uncontrolled release of ammonia from an engine of a vehicle. An estimated status of the engine is determined prior to an event, such as an estimated load on the engine prior to the vehicle going up a hill. A predictive model of uncontrolled ammonia release is generated for the estimated status. At least one engine-related countermeasure is selected based on the predictive model. If the predictive model of uncontrolled ammonia release with the selected countermeasures satisfies a threshold condition, then the selected engine-related countermeasure is employed.

A controller for controlling operation of an aftertreatment system that is configured to treat constituents of an exhaust gas produced by an engine, the aftertreatment system including a selective catalytic reduction (SCR) catalyst, the controller configured to: generate a short-term cumulative degradation estimate of the SCR catalyst corresponding to reversible degradation of the SCR catalyst due to sulfur and/or hydrocarbons based on a SCR catalyst temperature parameter; generate a long-term cumulative degradation estimate of the SCR catalyst corresponding to thermal aging of the SCR catalyst based on the SCR catalyst temperature parameter; generate a combined degradation estimate of the SCR catalyst based on the short-term cumulative degradation estimate and the long-term cumulative degradation estimate; and adjust an amount of reductant and/or an amount of hydrocarbons inserted into the aftertreatment system based on the combined degradation estimate of the SCR catalyst.