Systems and methods for simulating gas flow dynamics of a real hydrogen fuel cell system using a computer, wherein the real hydrogen fuel cell system includes a gas container volume network having gas container volumes interconnected by gas transport lines. The method includes defining volume element and flow channel classes, defining a plurality of volume instances and a plurality of flow channel instances, for each flow channel instance, creating a first interconnection representation that defines a source container volume and a destination container volume for the flow channel instance, wherein the first interconnection representation mimics a portion of the gas container volume network of the real hydrogen fuel cell system, and simulating, using the first interconnection representation, a thermodynamic state for each of the volume instances, the thermodynamic state representing thermodynamic parameter(s) in each container volume of the gas container volume network of the real hydrogen fuel cell system.

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 method for reducing deposits related to a reduction agent (RA) in a portion of an exhaust aftertreatment system (EAS) of an internal combustion engine (ICE) and comprising an injector for injecting the RA into said EAS, said portion located downstream of said injector, as seen in an intended direction of flow of exhaust gas in said EAS, said method comprising: identifying for said ICE, a future operating sequence (FOS) comprising a first temporal portion (t.sub.1) and a second temporal portion (t.sub.2) subsequent to t.sub.1, confirming that said FOS is suitable for reducing deposits and that said ICE operates in accordance with said FOS, in response to said confirming being affirmative, injecting a first dosage (d.sub.1) of RA into said EAS during at least a part of said t.sub.1 and injecting a second dosage (d.sub.2) of RA smaller than d.sub.1 into said EAS during at least a part of t.sub.2.

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 Kirchhoff's 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.

Systems and methods for simulating gas flow dynamics of a real hydrogen fuel cell system using a computer, wherein the real hydrogen fuel cell system includes a gas container volume network having gas container volumes interconnected by gas transport lines. The method includes defining volume element and flow channel classes, defining a plurality of volume instances and a plurality of flow channel instances, for each flow channel instance, creating a first interconnection representation that defines a source container volume and a destination container volume for the flow channel instance, wherein the first interconnection representation mimics a portion of the gas container volume network of the real hydrogen fuel cell system, and simulating, using the first interconnection representation, a thermodynamic state for each of the volume instances, the thermodynamic state representing thermodynamic parameter(s) in each container volume of the gas container volume network of the real hydrogen fuel cell system.

A method for estimating a heat generation distribution in a honeycomb structure includes: a first step of allowing a predetermined minute current to flow between electrode layers A1 and B1 to energize a honeycomb structure, and measuring surface potentials at multiple points; a second step of allowing a predetermined minute current to flow between electrode layers A2 and B2 to energize the honeycomb structure, and measuring surface potentials at multiple points; a third step of quantifying, based on the measured surface potentials at the multiple points, at least one of resistances at the multiple points in the honeycomb structure, resistance ratios for energization paths, voltage sharing ratios, and surface potentials of the electrode layers A1, A2, B1 and B2; and a step of estimating a heat generation distribution in the honeycomb structure based on the values quantified in the third step.

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.

A method comprising adjusting a fuel injection amount based on a fractional oxidation state of a catalyst, the fractional oxidation state based on reaction rates of grouped oxidant and reductant exhaust gas species throughout a catalyst and a low-dimensional physics-based model derived from a detailed two-dimensional model to obtain a one-dimensional model averaged over time and space that accounts for diffusion limitations in the washcoat and accurately predicts emissions during cold start.

A method for controlling a SCR catalytic converter of a vehicle, comprising a first step of modelling said at least one SCR catalytic converter as a plurality of NH3 storage cells (cell1, cell2, . . . , celln; cell1, cell2 . . . celln, cell1, cell2, . . . , celln), a second step of controlling only a first (cell1) of said plurality of storage cells, according to feedback control based on a reference value, and a third step of adapting said reference value on the basis of a storage level of at least another storage cell of said plurality of storage cells, wherein said first storage cell is arranged at an inlet of said SCR catalytic converter according an exhaust gas circulation.

In a method for a model-based determination of a temperature distribution of an exhaust gas post-treatment unit, a differentiation is made between steady operating states and non-steady operating states by taking into account the axial and the radial temperature distribution, and, on the basis of virtual segmentation of the post-treatment unit, in particular the radial heat transfer to the surroundings is taken into account in the model-based determination for steady operating states, and for non-steady operating states the heat transfer from the exhaust gas which flows axially through the post-treatment unit to the segments is taken into account by a heat transfer coefficient k.