A system for determining a performance status of an exhaust aftertreatment system may include determining an ammonia-to-nitrogen ratio using a sample ammonia input value and a sample NO.sub.x input value. An actual NO.sub.x input value and an actual ammonia input value can be received. An emission value from may be received from a first sensor. A NO.sub.x emission estimate, an ammonia slip estimate, and an optimal ammonia storage value for a selective catalytic reduction may be determined using an iterative inefficiency calculation based, at least in part, on the actual NO.sub.x input value, the actual ammonia input value, and the ammonia-to-nitrogen ratio; and the NO.sub.x emission estimate, the ammonia slip estimate, and the optimal ammonia storage value may be outputted to a diagnostic system.

Systems and methods for controlling a performance variable of an engine system are provided. An apparatus includes a response model circuit structured to apply a constraint to a response model that represents a relationship regarding a manipulated variable or a relationship between the performance variable and the manipulated variable. The apparatus further includes an optimization circuit structured to determine a target for the manipulated variable via the response model such that the target of the manipulated variable satisfies the constraint of the response model. The performance variable is indicative of performance of operation of the engine system and the manipulated variable is capable of affecting the performance variable. Operation of the engine system is adjusted based upon the target of the manipulated variable by controlling at least one of a fuel system or an air handling system of the engine system.

A method and a control unit for checking an exhaust gas system in a vehicle. A control unit in the vehicle receives data from sensors of the vehicle and sends out control commands to final control elements of the vehicle. The control unit is in communication connection with an external computer located outside of the vehicle. The external computer causes the control unit to make an active intervention in the exhaust gas system by actuating final control elements of the vehicle. The control unit receives sensor data from the exhaust gas system, which it forwards to the external computer. Based on the sensor data from the sensors, the external computer rates the exhaust gas system as “OK” or “manipulated”.

A method is provided for ascertaining a NO.sub.x concentration and an NH.sub.3 slip downstream from an SCR catalytic converter of an internal combustion engine of a vehicle. State variables of an internal combustion engine as first input variables and an updated NH.sub.3 fill level of the SCR catalytic converter as a second input variable cooperate with at least one machine learning algorithm or at least one stochastic model. The at least one machine learning algorithm or at least one stochastic model calculates the NO.sub.x concentration and the NH.sub.3 slip downstream from the SCR catalytic converter as a function of the first input variables and the second input variables and output the same as output variables.

The present invention discloses methods and devices for controlling a heated mixer, situated downstream of a Urea-Water Solution (UWS) injector, to reduce NOx emission in an exhaust system from combustion engines, wherein the exhaust system has a Selective Catalytic Reduction (SCR) catalyst situated downstream of the UWS injector and the heated mixer, Methods include: determining a NOx reduction efficiency of the SCR catalyst; evaluating at least one reductant Uniformity Index (UI) based on operating parameters of the exhaust system and a mixer power calculation map; and modifying a mixer temperature of the heated mixer by regulating power to the heated mixer based on at least one reductant UI in order to improve at least one reductant UI and/or improve the NOx reduction efficiency. Alternatively, the method further includes: detecting at least one potential improvement of at least one UI and/or the NOx reduction efficiency based on an increased ammonia mass.

An exhaust treatment system includes an SCRF device, a reductant delivery system, and an SCR storage module. The SCRF device includes a filter portion having a washcoat formed thereon that defines a washcoat thickness (WCT). The reductant delivery system is configured to inject a reductant that reacts with the washcoat based on a reductant storage model. The SCR storage module is in electrical communication with the reductant delivery system to provide the reductant storage model the amount of reductant to be injected based on the reductant storage model. The exhaust treatment system further includes a WCT compensation module configured to electrically communicate a WCT compensation value to the SCR storage module. The SCR storage module modifies the reductant storage model according to the WCT compensation value such that the amount of ammonia that slips from the SCRF device is reduced thereby increasing a storage efficiency of the SCRF device.

An exhaust gas purification apparatus for an internal combustion engine comprises an ammonia supplier which includes a storage unit configured to store a precursor of ammonia or ammonia (reducing agent or the like), and a controller programmed to carry out output restriction control as such control that an output of the internal combustion engine is restricted to be not more than a predetermined output such that a NOx purification rate brought about by the storage reduction NOx catalyst is within an allowable range if an amount of the reducing agent or the like stored in the storage unit is less than a predetermined storage amount.

A control system includes an electric heater disposed within an exhaust fluid flow pathway, and a control device for receiving at least one input selected from the group consisting of temperature readings along the exhaust fluid flow pathway, alternator power/current/voltage, battery power/current/voltage/state of charge, IAT and EAT profiles, mass flow rate of an exhaust fluid flow, NH.sub.3 slip, TCR characteristics of the heater, alternator speed, engine speed, state of aging of an aftertreatment component, state of aging of engine, aging degradation characteristics, a dosing rate and a temperature of DEF, NH.sub.3 storage condition of aftertreatment system, an ambient temperature, and combinations thereof. The control device modulates power to the heater based on the at least one input such that the heater provides different power output as a function of the at least one input and a continuously variable power output during operation of the exhaust system.

Implementations of systems and methods for detecting the failure of an selective catalytic reduction (SCR) catalyst may include a controller or one or more circuits for acquiring an ammonia to NOx ratio (ANR) value for exhaust gas flowing through an exhaust system, acquiring a conversion inefficiency value indicative of a conversion inefficiency of the SCR catalyst, acquire an NH.sub.3 slip value indicative of an amount of NH.sub.3 slip through the exhaust system downstream of the SCR catalyst, calculate a combined ANR/conversion inefficiency/NH3 slip (ACN) value based on the ANR value, conversion inefficiency value, and NH.sub.3 slip value, and indicating a failure of the SCR catalyst responsive to the calculated ACN value exceeding a predetermined threshold value.

An exhaust gas purification system for an internal combustion engine is provided with a filter including a selective catalytic reduction NOx catalyst carried thereon. Further, a post-catalyst is provided for an exhaust gas passage disposed on a downstream side from the filter. The post-catalyst has an oxidizing function, and the post-catalyst has such a function that the production of N.sub.2 based on the oxidation of ammonia is facilitated in a predetermined first temperature area. A filter regeneration process execution unit is programmed to control the temperature of the post-catalyst to be in the first temperature area while adjusting the temperature of the filter to be in a predetermined second temperature area lower than a filter regeneration temperature during a certain period of time.