Disclosed is a process for the dynamic monitoring of the flow rate of liquid additive consumed by a liquid-additive injector of an exhaust gas treatment system of a motor vehicle. The measurement of the pressure of the liquid makes it possible firstly to deduce the flow rate circulating through the orifice and secondly, by knowing the operating characteristic of the pump, to determine the flow rate of liquid additive actually delivered to the system for treating polluting gases. The process also provides a phase of characterizing the pump, including commanding the closure of the injector, measuring at least two pressure values for two different operating speeds of the pump, and updating the pump operating characteristics table on the basis of the pressure values measured.

A system for controlling reductant spray momentum for a target spray distribution includes an exhaust system having an exhaust conduit with exhaust flowing therethrough, a reductant injection system for injecting reductant into the exhaust flowing through the exhaust system based on one or more injection parameters, a reductant supply system for supplying reductant to the reductant injection system based on one or more supply parameters, and a controller. The controller is configured to access current vehicle, engine, exhaust, or reductant condition parameters, determine one or more control parameters based on a control model and the accessed current vehicle, engine, exhaust, or reductant condition parameters, and modify a value of the one or more injection parameters or the one or more supply parameters to control the reductant spray.

Systems and methods for diagnosing an exhaust aftertreatment system are provided. A controller determines, for each sensor of a plurality of sensors, one or more performance parameters based on measurement data obtained from the sensor that is indicative of a performance of the sensor or a component of the exhaust aftertreatment system. The controller determines, for each performance parameter, a corresponding degradation level indicator indicative of a performance degradation of the corresponding sensor or the corresponding component of the exhaust aftertreatment system. The controller can determine, for each degradation level indicator, a corresponding diagnosis threshold value for detecting an operational state of the corresponding sensor or the corresponding component of the exhaust aftertreatment system. The controller can determine a multipoint diagnosis threshold value based on the diagnosis threshold values, and determine an operational state of the aftertreatment system using the multipoint diagnosis threshold value.

A method for operating a conveying device for an aqueous urea solution in a motor vehicle, having a pump for conveying the aqueous urea solution, wherein the aqueous urea solution is conveyed from a tank along a pressure line to an injector, wherein the injector is arranged on an exhaust gas line and is designed to inject the aqueous urea solution into the exhaust gas line. The conveying speed of the pump is controlled depending on the opening operations and closing operations of the injector and/or the pressure conditions resulting therefrom in the conveying section between the pump and the injector.

A system for controlling reductant spray momentum for a target spray distribution includes an exhaust system having an exhaust conduit with exhaust flowing therethrough, a reductant injection system for injecting reductant into the exhaust flowing through the exhaust system based on one or more injection parameters, a reductant supply system for supplying reductant to the reductant injection system based on one or more supply parameters, and a controller. The controller is configured to access current vehicle, engine, exhaust, or reductant condition parameters, determine one or more control parameters based on a control model and the accessed current CZ vehicle, engine, exhaust, or reductant condition parameters, and modify a value of the one or more injection parameters or the one or more supply parameters to control the reductant spray.

The invention proposes a method for operating a metering system (32) with a plurality of metering valves (34, 35) for an SCR catalyst system, in which opening times for the injection of reducing agent are calculated for the metering valves (34, 35) based on a metering amount requirement. In the calculations of the opening times, a metering-valve-specific adaptation factor is used, w herein a deviation (Δp) of a system pressure (p.sub.ist) in the metering system (32) from a target pressure (p.sub.soll) and a weighting factor are used for calculation of the metering-valve-specific adaptation factor. The weighting factor depends on a proportion (r.sub.34, r.sub.35) of the required metering amount ((formula (I)), (formula (II)) of the respective metering valve (34,35) in relation to a total metering amount ((formula (I)), (formula (II)) of all metering valves (34, 35).

An internal combustion engine exhaust purification device includes a filter which is disposed in an exhaust path and collects particulate matter in exhaust gas, an injection valve which is disposed upstream of the filter in the exhaust path and injects fuel into the exhaust path, a fuel pump which supplies a fuel to the injection valve, a shut-off valve which is interposed between the fuel pump and the injection valve, and selectively shuts off a fuel supply from the fuel pump to the injection valve, and a control unit which controls the injection valve and the shut-off valve. The control unit closes the shut-off valve when the control unit detects an opened adherence failure of the injection valve and detects an abnormal temperature rise of the filter during regeneration of the filter.

Methods and systems are provided for estimation of a volume of liquid diesel exhaust fluid (DEF) contained within a DEF tank. In one example, a method for the estimation of the volume of liquid DEF in a DEF tank during DEF freezing conditions may include activating a heater contained within the DEF tank, and then switching estimation of the volume of liquid DEF via a first transfer function to estimation of the volume of liquid DEF via a second transfer function.

A system has a pump and an injector coupled to the pump. The system further comprises a controller coupled to the pump and the injector. The controller is structured to: determine a change of reductant flow relative to a change of pump rate of the pump; and generate a status command indicative of at least one of an under-restricted injector or an over-restricted injector in response to the determination of the change of reductant flow relative to the change of pump rate of the pump.

A method of detecting a valve opening or closing event in a solenoid operated reductant injector valve includes applying a voltage to the solenoid to actuate the valve, the voltage having a chopped waveform. A resultant current through the solenoid is sampled at local maxima and minima. Values of a difference between the local maxima and subsequent local minima or between local minima and subsequent local maxima are determined. A rate of change of the difference values are determined and a valve opening or closing event based on the rate of change is determined.