Provided is a method for controlling an exhaust gas treatment system, wherein the system includes an exhaust gas stream supplied by an exhaust gas source to a selective catalytic reduction (SCR) device and a particulate filter device. The method comprises detecting a threshold level of reductant deposits proximate the SCR device, and initiating a selective catalytic reduction device service in response thereto. A threshold level of reductant deposits is detected using a reductant deposit model comprising determining an actual SCR NO.sub.x conversion using measured process variables; and comparing the actual SCR NO.sub.x conversion to a calibrated NO.sub.x conversion value. The calibrated NO.sub.x conversion value is determined using exhaust gas flow and system temperature values which substantially correspond to the process variables under which the actual SCR NO.sub.x conversion was determined. The device service can include increasing the exhaust gas temperature or initiating an active regeneration of the particulate filter device.

A selective catalytic reduction device (SCR) system performs intrusive steady state dosing correction (SSDC) when a NOx error between a predicted and measured downstream NOx value exceeds a threshold. In SSDC, if NOx breakthrough or NH3 slip is detected above a SSDC threshold, a short term reductant dosing adaptation occurs. Optionally long term dosing adaptations occur if the magnitude of previous short term adaptations exceed a short term adaptation threshold. If SSDC is insufficiently improving SCR performance based on the number of intrusive events occurring within a period of time and the change in NOx error during the time period, a method includes modifying the SSDC protocol by one or more of increasing the duration of short term adaptations, decreasing the SSDC threshold, and reducing the short term adaptation threshold. The method further includes subsequently inhibiting intrusive events from occurring.

A selective catalytic reduction device (SCR) system performs intrusive steady state dosing correction (SSDC) when a NOx error between a predicted and measured downstream NOx value exceeds a threshold. In SSDC, if NOx breakthrough or NH3 slip is detected above a SSDC threshold, a short term reductant dosing adaptation occurs. Optionally long term dosing adaptations occur if the magnitude of previous short term adaptations exceed a short term adaptation threshold. If SSDC is insufficiently improving SCR performance based on the number of intrusive events occurring within a period of time and the change in NOx error during the time period, a method includes modifying the SSDC protocol by one or more of increasing the duration of short term adaptations, decreasing the SSDC threshold, and reducing the short term adaptation threshold. The method further includes subsequently inhibiting intrusive events from occurring.

Methods and systems are provided for maintaining a database with details of frequently travelled routes and selecting a travel route for a vehicle from the database based on particulate filter regeneration requirements. In one example, a method may include selecting one or more routes from the database based on a current particulate filter soot level, fuel efficiency, travel time, operator behavior, etc., ranking the routes based on the particulate filter regeneration efficiency of each of the one or more routes. At vehicle key-off, the database may be updated with information regarding the travelled route including a level of particulate filter regeneration achieved during the drive cycle.

An exhaust gas control apparatus for the internal combustion engine includes a catalyst disposed in an exhaust passage, an upstream air-fuel ratio sensor configured to detect an air-fuel ratio of in-flow exhaust gas that flows into the catalyst, a downstream air-fuel ratio sensor configured to detect an air-fuel ratio of out-flow exhaust gas that flows out of the catalyst, and an electronic control unit configured to control the air-fuel ratio of the in-flow exhaust gas. The electronic control unit is configured to, when a predetermined condition is satisfied, control the air-fuel ratio of the in-flow exhaust gas based on an output from the downstream air-fuel ratio sensor without using an output from the upstream air-fuel ratio sensor. The electronic control unit is configured to, when the predetermined condition is not satisfied, control the air-fuel ratio of the in-flow exhaust gas based on the output from the upstream air-fuel ratio sensor.

Methods and systems are provided for catalyst control. In one example, a method may include controlling an air-fuel ratio downstream of a catalyst by adjusting fuel injection. The fuel injection is adjusted based on control parameters updated online through system identification at a point of feedback control instability.

A method for adapting a characteristic curve of a nitrogen oxide sensor of a combustion engine with exhaust gas recirculation having the first nitrogen oxide sensor upstream of an SCR catalytic converter and a second nitrogen oxide sensor downstream of the SCR catalytic converter includes determining that a particle filter is in a regeneration phase, increasing the exhaust gas recirculation rate, interrupting the supply of urea by a urea injection device, acquiring first nitrogen oxide values from signals generated by the first nitrogen oxide sensor, determining that the first nitrogen oxide values are within a first nitrogen oxide interval, acquiring values from second nitrogen oxide signals generated by the second nitrogen oxide sensor, and determining that the second nitrogen oxide values are within a second nitrogen oxide interval, and adapting the characteristic curve of the first nitrogen oxide sensor by the second nitrogen oxide values.

A computer implemented method for controlling the operation of an engine system in a vehicle is provided. The engine system comprising an engine and an exhaust aftertreatment system for reducing at least NOx emissions of the exhaust gases from the engine using a reductant, the engine system comprising a plurality of engine system components configured to perform a plurality of NOx emission reducing activities.

A method for controlling an exhaust gas treatment system is provided. The exhaust gas treatment system includes an exhaust gas stream supplied by an exhaust gas source to a selective catalytic reduction device, and a reductant supply source utilizing a volumetric pump. The exhaust gas source can include an internal combustion engine (ICE), such as a gasoline or diesel ICE. The method for controlling an exhaust gas treatment system includes commanding a reductant dosing quantity, determining a volumetric pump energizing time, determining an energizing time correction, and energizing the pump. The volumetric pump can comprise pump logic, and the volumetric pump energizing time can be determined by the pump logic. The energizing time correction can be determined using a calibration table. The calibration table can prescribe an energizing time correction based on a current pump pressure and the commanded dosing quantity.

A method and system controls a regeneration of a particle filter of an internal combustion engine. A first value is measured for the oxygen content in exhaust gas upstream from the particle filter. A second value is measured for the oxygen content in exhaust gas downstream from the particle filter. The particle filter is determined to be free of soot when the second value for the oxygen content is equal to the first value for the oxygen content.