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.

A method for predicting urea crystal build-up in an engine system when operating according to an intended drive cycle. The method includes providing data representing engine operational conditions for the internal combustion engine during the intended drive cycle, wherein the data comprises values for at least engine speed and engine torque distributed over a time period representing the intended drive cycle; determining values and time variation for at least one exhaust parameter during the time period of the intended drive cycle when the engine system is operated according to the engine operational condition data; providing a reference relation between values and time variation for the at least one exhaust parameter and an expected urea crystal build-up in the engine system when operating the engine system at different engine operational conditions, predicting urea crystal build-up in the engine system when operating according to the intended drive cycle by comparing the determined values and time variation for the at least one exhaust parameter with the reference relation.

A method for predicting soot build-up in an engine system when operating according to an intended drive cycle. The engine system includes an internal combustion engine and an exhaust gas aftertreatment system provided with a particulate filter. The method includes providing data representing engine operational conditions for the internal combustion engine during the intended drive cycle, wherein the data comprises values for at least engine speed and engine torque distributed over a time period representing the intended drive cycle; determining a working temperature for the exhaust gas aftertreatment system during the intended drive cycle based on the data representing the engine operational conditions; providing a reference relation between working temperature of the exhaust gas aftertreatment system and a corresponding estimated magnitude of a build-up of soot in the exhaust gas aftertreatment system; and predicting soot build-up in the engine system when operating according to the intended drive cycle by comparing the determined working temperature for the exhaust gas aftertreatment system with the reference relation.

Various embodiments of the teachings herein include a method for determining the nitrogen oxide content and/or ammonia content in the exhaust gas of an internal combustion engine with a catalytic converter arranged in an exhaust tract and an exhaust gas sensor downstream of the catalytic converter. In some embodiments, the method comprises: determining an operating state of the internal combustion engine, the operating state indicating either lean operation or rich operation of the internal combustion engine; generating a signal using the exhaust gas sensor; and determining the nitrogen oxide content and/or ammonia content in the exhaust gas at least partially based on the determined operating state of the internal combustion engine and the signal.

A computer-implemented method for determining whether a reductant (e.g. urea) injector is clogged is provided. The method includes receiving data indicative of an injector duty cycle and a pump duty cycle. Using a trained machine learning module, at least a first value is calculated, indicative of a probability of the injector being clogged. The method further includes providing, based on the first value, an indication of whether the reductant injector is clogged. A device for providing the indication using the method, a computer program, a reductant injector system, and e.g. a combustion engine including such a reductant injector system are also provided.

Methods and systems are provided to heat a catalyst of an after-treatment system for a vehicle. The after-treatment system is powered by a battery. An operational parameter of the battery and the driving mode of the vehicle is determined. After receiving an indication that a first operational parameter threshold has been surpassed and a torque demand of the vehicle has been predicted, heat is provided to the catalyst of the after-treatment system based on the predicted torque demand of the vehicle surpassing a second operational parameter threshold.

Various embodiments of the teachings herein include methods for determining the sulfur content in an exhaust tract of a motor vehicle. The method may include: determining a change in the nitrogen oxide abatement efficiency of a coated particulate filter arranged in the exhaust tract and/or a determined ammonia storage capacity change of a coated particulate filter arranged in the exhaust tract; comparing the determined change to a threshold value; identifying an excessive sulfur content if the comparison shows that the determined change exceeds the threshold value; and undertaking one or more corrective actions in response to identifying an excessive sulfur content.

A process is provided for regenerating an exhaust gas after-treatment device in an exhaust line of an internal combustion engine arrangement, the exhaust line including a particle filter. The process includes identifying when soot loading of the particle filter exceeds a predetermined level. After that, temperature of exhaust gases at the particle filter is maintained within a first temperature range until at least one of a predetermined period of time has lapsed or a determination is made that soot loading of the particle filter is below the predetermined level. After that, the temperature of the exhaust gases at the particle filter is increased to within a second temperature range above the first temperature range. An internal combustion engine arrangement is also disclosed.

An exhaust purification system includes: a NOx reduction catalyst for reducing and purifying NOx in an exhaust gas; a catalyst regeneration control module for executing a catalyst regeneration process of restoring a NOx purification capacity of the NOx reduction catalyst by switching an air-fuel ratio of the exhaust gas from a lean state to a rich state by using in parallel an air system control to reduce an intake air amount and an injection system control to increase a fuel injection amount; an exhaust gas temperature sensor that is provided on a downstream side of the NOx reduction catalyst on an exhaust passageway; a catalyst temperature estimating module for estimating a catalyst temperature of the NOx reduction catalyst; a temperature sensor value estimating module for estimating a sensor value of the exhaust gas temperature sensor; and an abnormality determination module for determining on an abnormality of a catalyst regeneration process.