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.

An auxiliary system automatically supplies diesel exhaust fluid (DEF) to a diesel engine onboard DEF tank to enable prolonged unattended operation. The system includes an auxiliary DEF tank and supply line, a controller, pump, air inlet, and three-way valve configured to switch the pump inlet between the auxiliary DEF tank and air. In response to low-level DEF, the pump delivers DEF to replenish the onboard DEF tank. The controller calculates onboard DEF tank volume based on the delivered volume of DEF, and DEF level data received from an ECM, to enable replenishment control regardless of engine make and model. In response to high-level DEF, engine stoppage, or system fault, the controller switches the pump inlet to air and runs the pump to purge DEF from the supply line. The auxiliary system may be skid-mounted, portable, and configured to supply DEF to multiple diesel engines.

A method (200) for ascertaining a catalytic converter state is proposed, wherein an exhaust-gas catalytic converter (130) is monitored on the basis of a catalytic converter model. Here, the catalytic converter model is adapted (250) in a manner dependent on measured values detected by means of one or more sensors (145, 147), wherein a frequency and/or a degree of the adaptation of the catalytic converter model is detected (260). The catalytic converter state is ascertained (270) as non-critical if the frequency and/or the degree of the adaptation do not exceed a predeterminable threshold value or is ascertained (270) as critical if the frequency and/or the degree of the adaptation exceed the predeterminable threshold value.

A method of detecting a need for regeneration of an exhaust particulate filter is described. A first pressure drop is detected in a flow section of an exhaust system which includes the exhaust particulate filter. In addition, an exhaust gas temperature is determined. An exhaust gas mass flow flowing through the exhaust particulate filter is then calculated on the basis of the exhaust gas temperature and the pressure drop. Furthermore, a second pressure drop at the exhaust particulate filter is determined. A need for regeneration is detected when the second pressure drop exceeds a predefined pressure limit value that is dependent on the exhaust gas mass flow. Moreover, an exhaust system for an internal combustion engine is presented which includes an exhaust particulate filter.

A controller is configured to perform a process of obtaining an exhaust pressure upstream of a filter inside an exhaust passage and an intake air amount detected by an air flowmeter, when the filter in which a deposition amount of particulate matter is a specified amount is referred to as a reference filter, a calculation process of calculating an exhaust pressure rate that indicates a ratio of the obtained exhaust pressure to an exhaust pressure at the reference filter for the obtained intake air amount, and a setting process of setting the exhaust pressure rate that is maintained at a specific value during engine operation.

The invention relates to a method for determining a loading of a soot filter with soot particles from an exhaust gas mass flow of an internal combustion engine in a motor vehicle, a control device for an internal combustion engine having a soot filter, and a computer program product for carrying out the method. In the first step 100 of the method a characteristic curve for the relationship between the exhaust gas mass flow, exhaust gas temperature, ambient pressure, and pressure drop across the soot filter without loading is determined; in the second step 200 a second exhaust gas mass flow and a second pressure drop that occurs during loading of the soot filter are determined; in the third step 300, from the characteristic curve the first pressure drop is determined for which the first and second exhaust gas mass flows have the same value; in the fourth step 400 an estimated value for the loading of the soot filter is computed via a real-time parameter estimation, preferably by use of the gradient method, based on the previously determined parameters. The method allows a reliable determination of the instantaneous loading of a particulate filter, regardless of the type of measuring signals used in each case for characterizing the loading behavior of the soot filter.

A method includes: interpreting first oxygen data acquired by a first nitrous oxide (NOx) sensor indicative of a first amount of oxygen in an exhaust flow at a location in or proximate to an exhaust aftertreatment system, wherein the exhaust aftertreatment system is in exhaust gas receiving communication with an engine; estimating an amount of oxygen in the exhaust flow entering the exhaust aftertreatment system from the engine based on engine operation data; and, determining that the NOx sensor is faulty based on determining that a difference between the first amount of oxygen and the estimated amount of oxygen is greater than a threshold value.

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 modular exhaust subsystem for purifying an exhaust gas feedstream of a compression-ignition internal combustion engine upstream of a base exhaust aftertreatment system includes a selective catalytic reduction (SCR) catalyst, and a first exhaust gas sensor and a first temperature sensor that are arranged to monitor the SCR catalyst. A reductant delivery system is arranged to inject a reductant upstream of the SCR catalyst. A controller is in communication with an engine-out exhaust gas sensor, a second exhaust gas sensor and a second temperature sensor that are arranged to monitor the base exhaust aftertreatment system. The controller controls the reductant delivery system to inject the reductant into the exhaust gas feedstream upstream of the SCR catalyst based upon inputs from the first and second exhaust gas sensors, the engine-out exhaust gas sensor, and the first and second temperature sensors.

A process for controlled heating of a sensor of an aftertreatment system comprising accessing several parameters, including an exhaust mass flow, an outlet temperature, an ambient air temperature, and an ambient air velocity, calculating a temperature of the sensor based on a thermal model and the accessed parameters, comparing the calculated temperature to a threshold temperature, and activating a controlled heating process for the sensor responsive to the calculated temperature being below the threshold temperature. The controlled heating process can include activating a heater to heat the sensor.