Disclosed is a method for diagnosing functionality of dosing units of a fluid dosing system comprising at least two dosing units, a tank unit for holding a fluid, and a pump unit for pressurizing the fluid for the dosing units. The method comprises determining a first hydraulic stiffness value on the basis of first pressure variations and determining a second hydraulic stiffness value on the basis of said second pressure variations. The first hydraulic stiffness value and second hydraulic stiffness value are compared. In a case where the first hydraulic stiffness value and second hydraulic stiffness value differ to a certain extent, concluding that malfunction of at least one of said dosing units is at hand, and in a case where the first hydraulic stiffness value and the second hydraulic stiffness value do not differ to said certain extent, concluding that the first and second dosing units function as intended.

Approaches for predicting parameters contributing to engine emissions are described. In an example, the values of control parameters may be obtained from the vehicle sensors. Based on the obtained values of the control parameters, estimated emission value may be determined pertaining to a correlation criterion reflecting a predetermined relationship between the obtained control parameter and engine emission. Further, the contribution index of each of the individual control parameters may be identified. Further, based on the estimated emission value and the contribution index, aggregated emission value corresponding to the exhausted emission from the engine for particular trip may be calculated.

A method (200) for diagnosing the functionality of a burner (100), comprising: determining a lambda value (210) of an exhaust gas of the burner (100), comparing (220) the determined lambda value to a time-based changing lambda threshold (225), and detecting a malfunction (280) when the determined lambda value exceeds the time-based changing lambda threshold (225). Furthermore, a computing unit and a computer program for carrying out such a method (200) are proposed.

The present invention relates to a method for diagnosing aftertreatment of exhaust gases resulting from combustion, wherein at least a first substance resulting from said combustion is reduced by supplying additive to an exhaust gas stream resulting from said combustion and use of a first reduction catalytic converter. The method includes: estimating an accumulated expected reduction of said first substance during a first period of time, determining an accumulated actual reduction of said first substance during a period of time at least substantially overlapping said first period of time, and generating a signal indicating a fault in said reduction of said first substance when said accumulated actual reduction differs from said accumulated expected reduction by a predetermined difference in occurrence of said first substance. The invention also relates to a corresponding system.

The present disclosure describes methods for evaluating NOx conversion efficiency of a close coupled SCR unit of an EAS including the close coupled SCR unit and a downstream SCR unit. The determined NOx conversion efficiency of the close coupled SCR unit is used to diagnose the close coupled SCR unit and or EAS and to control operation parameters of the EAS and/or internal combustion engine operably connected to the EAS.

A heavy-duty truck has a diesel engine, an exhaust after-treatment system, and an engine control unit. The exhaust after-treatment system includes a close-coupled selective catalytic reduction system and an underbody selective catalytic reduction system, a first NO.sub.x sensor upstream of the close-coupled selective catalytic reduction system, a second NO.sub.x sensor between the two selective catalytic reduction systems, and a third NO.sub.x sensor downstream of the underbody selective catalytic reduction system. The engine control unit may perform methods allowing intrusive diagnostics to be performed on exhaust gas NO.sub.x sensors using the selective catalytic reduction systems during normal operation of the heavy-duty truck.

The present disclosure describes methods for evaluating quality of DEF dosed to an EAS including a close coupled SCR unit a downstream SCR unit. A NOx conversion efficiency of the close coupled SCR unit and a NOx conversion efficiency of the downstream SCR unit are used to evaluate quality of DEF. In some embodiments, the NOx conversion efficiency of close coupled SCR unit is used to evaluate quality of DEF. Operation of an EAS using the results of the evaluation of quality of DEF are described.

The invention relates to a method, system, and computer program product for diagnosing an exhaust gas processing configuration for a combustion engine of a vehicle, said configuration comprising two SCR-units, two NOx-sensors and two reducing agent dosing units suitably arranged, comprising the steps of: performing a series of reducing agent dosing operations by a first reducing agent dosing unit; comparing measured NOx-contents measured by a first NOx-sensor and a second NOx-sensor related to said operations; and if the respective NOx-content measured by the respective NOx-sensors during the performed reducing agent dosing operations are substantially equal, determining that the respective NOx-sensors provide a proper performance.

An automated diesel exhaust fluid (DEF) system and method for refilling DEF. The automated DEF system provides DEF refilling after an initial setup and without manual intervention. The automated DEF system includes a electric DEF flow control device that controls the flow of DEF. The electric DEF flow control device may include control circuitry, an electrics enclosure that encloses the control circuity, an electric fluid sensor, a valve, a beacon light, a status light, a button, a threaded swivel connection, and a mandrel on the inside of the threaded swivel connection.

A method for estimating a quality of reductant in an engine aftertreatment system for an engine using a virtual sensor, the method comprising: determining whether an enablement condition is met, wherein the enablement condition is one or more of: a reductant fill condition determined based on data received from one or more float sensors associated with the engine; a machine start condition determined based on machine speed data obtained from a speed sensor associated with the engine; and/or a rationality check condition determined based on data associated with a fault of one or more sensors associated with the engine; upon determining that the enablement condition is met, receiving NOx measurement data obtained from at least one NOx sensor; generating a reductant quality value based on the NOx measurement data; and outputting a reductant quality determination based on the reductant quality value.