A method of determining a flow resistance across a particulate filter located downstream of an internal combustion engine in an exhaust system. The method comprises measuring a first differential pressure across the particulate filter, measuring a second differential pressure downstream of the particulate filter, determining a pressure ratio of the first differential pressure and the second differential pressure, and from said pressure ratio, determining a flow resistance across the particulate filter. The second differential pressure is measured across a selective catalytic reduction system.

A control system for use in a fluid flow application is provided. The control system includes a heater having at least one resistive heating element. The heater is adapted to heat the fluid flow. The control system further includes a control device that uses heat loss from at least one resistive heating element to determine flow characteristics of the fluid flow.

The invention relates to a regeneration air system for an exhaust aftertreatment system of an internal combustion engine and to such an exhaust aftertreatment system. The regeneration air system comprises a regeneration air delivery element, a regeneration air duct, and a regeneration air valve. A sensor system is provided in the regeneration air duct with which a regeneration air mass flow {dot over (m)}.sub.SL can be determined exactly. The exhaust aftertreatment system comprises an exhaust system with an exhaust duct in which, in the direction of flow of an exhaust gas through the exhaust duct, a three-way catalytic converter is arranged underhood and a four-way catalytic converter is arranged downstream. A provision is made that an intake point for the regeneration air from the regeneration air system is formed on the exhaust duct downstream from the underhood three-way catalytic converter and upstream from the four-way catalytic converter.

A method for detecting a dosing error of a reduction agent in a dosing module of an SCR catalytic converter system. The SCR catalytic converter system comprises the dosing module, which has a dosing valve and a flow valve as well as a delivery module with delivery pump. The SCR catalytic converter system, furthermore, has a return, in which a further flow valve is arranged. Said flow valve changes an effective cross-sectional area of the return. The method herein comprises the following steps: at the beginning, the dosing valve is closed (200). At a first pressure value (p.sub.1) in the system the delivery pump is switched off (201) and a measurement (202) of a first pressure rate (.sub.RL.sup.dynamic) of the flow valve of the return subsequently takes place. Additional operation of the pump and the dosing valve occurs and a ratio of pressure rates is determined.

A heater system for an exhaust system is provided. The heater system includes a heater disposed in an exhaust conduit. The heater includes a plurality of heating elements disposed in the exhaust conduit. A heating control module controls the plurality of heating elements differently according to operating conditions specific to each heating element. In other forms, the heater system for an exhaust system has a plurality of heating zones, instead of a plurality of heating elements. The heating control module controls the plurality of heating zones differently according to operating conditions specific to each heating zone.

A method of predicting temperature of at least one location in a fluid flow system that has a heating system for heating fluid. The method includes obtaining a mass flow rate of fluid flow of the fluid flow system, obtaining at least one of a fluid outlet temperature and a fluid inlet temperature of a heater of the heating system, obtaining power provided to the heater, and calculating temperature at the at least one location based on a model of the fluid flow system and the obtained mass flow rate, fluid outlet temperature, and fluid inlet temperature.

A method for determining the state of loading of a particle filter in an exhaust system of a turbocharged internal combustion engine is provided. To determine the state of loading, a position of a control mechanism of the turbine of the exhaust turbocharger is detected and compared with the position during operation of the internal combustion engine with the same operating parameters with the particle filter unladen. An air mass meter is provided in order to be able to distinguish a change in the pressure situation at the turbine of the exhaust turbocharger due to a rise in the exhaust gas backpressure owing to increasing loading of the particle filter from a change in the pressure situation owing to leakage of the air supply system. An internal combustion engine having a control unit which is configured to carry out such a method is also provided.

A method includes determining, by a controller, a total emissions amount from a plurality of engines; comparing, by the controller, the total emissions amount to a predetermined threshold, wherein the predetermined threshold includes an alert value, an adjustment value, and a deactivation value, the deactivation value being greater than the adjustment value, which is greater than the alert value; deactivating, by the controller, at least one engine in response to the total emissions amount being at or greater than the deactivation value; adjusting, by the controller, operation of at least one engine in the plurality of engines in response to the total emissions amount being at or greater than the adjustment value but less than the deactivation value; and providing, by the controller, an alert in response to the total emissions amount being at or greater than the alert value but less than the adjustment value.

A method (200) for ascertaining an air volume provided by means of an electric air pump (134) in an exhaust system (120) of an internal combustion engine (110), including detecting at least one activation parameter (5) of the air pump and ascertaining (220) a provided air mass flow rate (8) on the basis of a calculation specification from the at least one activation parameter (5) by utilizing an inertia of the air pump (134) and/or an inertia of the air upstream and/or downstream from the air pump (134) and/or a differential pressure from upstream from the air pump to downstream from the air pump. In addition, a processing unit and a computer program for carrying out a method (200) of this type is provided.

A chemical species mass flow meter measurement system for use in fluid mixture streams includes a chemical species concentration detection analyzer physically located within a fluid volume flow rate sensing probe along with bulk temperature and pressure sensing devices for relating to standard conditions. The system uses concentration detection analyzers specifically suited to the intended application. Applications include the measurement of exhaust mass emissions from vehicles, the fuel economy of vehicles, as well as the measurement of the mass flow rate of chemical species of interest in general industrial processes.