The invention concerns a method for controlling an SCR catalytic converter. A first modelled level of ammonia (NH3_mod1) and a second modelled level of ammonia (NH3_mod2) of the SCR catalytic converter are determined from two different models. The second modelled level of ammonia (NH3_mod2) is assessed by comparing it with the first modelled level of ammonia (NH3_mod1).

A method of recognizing deactivation of an exhaust gas catalytic converter is disclosed. For this purpose, coverage of storage sites of the exhaust gas catalytic converter with rich gas components is modeled (60) and the deactivation is recognized from a proportion of the occupied storage sites in a total number of storage sites.

A method of estimating the oxygen storage capacity of a catalyst includes providing an engine system having an internal combustion engine and an exhaust system having a catalyst and an oxygen sensor, providing a three-way catalyst observer model having a Kalman filter and a three-way catalyst kinetic model, estimating a three-way catalyst next time step state and a modeling error, linearizing the three-way catalyst observer model, filtering the estimated three-way catalyst next time step state, and calculating a covariance.

A method for measuring a heat generation distribution in a honeycomb structure includes: applying a voltage to a pair of electrode layers of the honeycomb structure to bring the honeycomb structure to an electrically conductive state; measuring resistance values R.sub.n between two different points on the surface of an outer peripheral wall of the honeycomb structure; estimating a current value I.sub.n flowing between the two points using Kirchhoffs law based on each of the resistance values R.sub.n between the two different points, and calculating a heat value generated for each of the resistance values R.sub.n based on each of the resistance values R.sub.n and the current value I.sub.n; and estimating a heat generation distribution in the honeycomb structure based on both the positions at which each of the resistance values R.sub.n is measured, and the heat value calculated from each of the resistance values R.sub.n, in the honeycomb structure.

A catalyst deterioration detection device is provided to detect deterioration of a catalyst provided in an exhaust passage of an internal combustion engine. The catalyst deterioration detection device includes a storage device and processing circuitry. The storage device stores map data specifying a mapping that uses time series data of an excess amount variable in a first predetermined period and time series data of a downstream detection variable in a second predetermined period as inputs to output a deterioration level variable. The processing circuitry executes an acquisition process that acquires data, a deterioration level variable calculation process that calculates a deterioration level variable of the catalyst based on an output of the mapping using the data acquired by the acquisition process as an input. The map data includes data that is learned through machine learning.

Evaluation method of exhaust gas simulation capable of simply and appropriately evaluating the validity of the simulation is provided. In analysis data, an analysis amplitude curve is calculated in which a change in the concentration of virtual exhaust gas at the observation point in the converged pipe portion is plotted, and an analysis time interval between the zero point and the reference point in the analysis amplitude curve is plotted. In actual measurement data, an actual amplitude curve is provided in which a change in the specific gas component at an observation point is measured with time, and an actual time interval is provided in which a time interval from a zero point to a reference point in the actual amplitude curve. The analysis data is determined as valid when a difference between the analysis time interval and the actual time interval is within a predetermined correlation range.

Provided is an exhaust purification system that may include: a first catalyst installed on a rear exhaust pipe of an engine; a selective catalytic reduction (SCR) catalyst installed on the rear exhaust pipe of the first catalyst; a reducing agent injector which is installed on an exhaust pipe between the first catalyst and the SCR catalyst and configured to inject a reducing agent; and a controller configured to control an amount of reducing agent injected from the reducing agent injector. /The controller may calculate a total amount of ammonia adsorbed in the SCR catalyst, a required amount of reducing agent based on a total amount of ammonia adsorbed in the SCR catalyst, and the amount of nitrogen oxide introduced into the SCR catalyst, and then control a reducing agent injector to inject the required amount of reducing agent.

Systems and associated methods of treating diesel exhaust in a vehicle are disclosed. An example method includes providing an exhaust aftertreatment device in an exhaust tailpipe, and a first nitrogen oxide (NO.sub.x) sensor upstream of the exhaust aftertreatment device, with the exhaust aftertreatment device configured to reduce NO.sub.x present in an exhaust flow through the exhaust aftertreatment device with a treatment fluid applied to the exhaust flow. This example method may also include measuring a concentration of NO.sub.x in the exhaust flow with the first sensor, determining an error in the measurement of the NO.sub.x concentration, and applying a learning corrective adjustment in a subsequent measurement of the NO.sub.x concentration in the exhaust flow in response to that determination. A first magnitude of the learning corrective adjustment may be based at least in part upon a second magnitude of the error in the measurement.

A method for determining a conversion capability of one or multiple exhaust gas catalytic converters, downstream from an internal combustion engine. The method includes ascertaining a respective local temperature at multiple locations within the one or the multiple catalytic converters, ascertaining a local conversion capability for a section or a partial volume of the one or the multiple catalytic converters based on the local temperature, and ascertaining a global conversion capability of the one or the multiple catalytic converters based on the ascertained local conversion capabilities. A processing unit and a computer program product for carrying out such a method are also described.

A system includes an aftertreatment system and a controller coupled to the aftertreatment system. The controller is configured to generate a spatially resolved model of a catalyst of the aftertreatment system. The controller is further configured to adjust the spatially resolved model based on one or more sensed values from at least one sensor upstream of the one or more portions and at least one sensor downstream of the one or more portions.