DE102022105407A1 - Method and device for operating a urea metering element - Google Patents

Abstract

According to the invention, the technology disclosed here relates to a device (101, 320) for operating a metering element (112) of an SCR system (120) to bring about a selective catalytic reaction of nitrogen oxides in an exhaust gas (111) of an internal combustion engine, wherein the SCR system ( 120) comprises a urea line (108) via which urea (103) is provided to the metering element (112). The device (101, 320) is set up to determine parameter values of one or more operating parameters (301) in relation to an operating state of the urea line (108) and/or the metering element (112). The device (101, 320) is further set up to operate the metering element (112) depending on the determined parameter values of the one or more operating parameters (301).

Description

The technology disclosed here relates to a method and a corresponding device for operating a metering element for urea, in particular for a urea-water mixture, such as AdBlue®.

A vehicle with a diesel engine typically has a system that adds urea to the diesel engine's exhaust gases to remove nitrogen oxides from the exhaust gases as part of a selective catalytic reaction (SCR).

A reliable and comprehensive reduction of nitrogen oxides typically requires precise metering of the amount of urea added to the exhaust gases.

It is a preferred object of the technology disclosed herein to reduce or eliminate at least one disadvantage of a previously known solution or to propose an alternative solution. It is a preferred object of the technology disclosed here to efficiently enable particularly precise metering of urea for an SCR system in a vehicle with a diesel engine.

The task(s) is/are solved by the subject matter of the independent patent claims. The dependent claims represent preferred embodiments.

According to one aspect, a device for operating a metering element (e.g. a valve and/or an injection nozzle) of an SCR system is described. The SCR system is designed to bring about a selective catalytic reaction of nitrogen oxides in the exhaust gas of an internal combustion engine (in particular a diesel engine). The SCR system includes a urea line via which urea (in particular a urea-water mixture) is provided to the metering element. The urea line can be 1 meter or more in length. Furthermore, the urea line may have a diameter that is smaller than the length of the urea line by a factor of 100 or more, or 1000 or more.

The metering element can be designed to inject urea from the urea line into an exhaust line with the exhaust gas of the internal combustion engine. Injection pulses can be effected by the dosing element with a specific repetition rate and/or frequency. An injection pulse can have a specific pulse duration. Furthermore, the metering element can have a certain degree of opening during an injection pulse. The repetition rate or frequency, the pulse duration and/or, if applicable, the degree of opening can be changed in order to change the amount of urea that is injected into the exhaust line by the metering element (per unit of time). In a preferred example, the metering element is operated in a binary manner to either completely close or fully open the metering element. The metering element then has a specific opening and closing characteristic as part of an injection pulse. In this case, there is no adjustment of the degree of opening of the dosing element (e.g. through a proportional control).

The device is set up to determine parameter values of one or more operating parameters in relation to the (current) operating state of the urea line and/or the metering element. The one or more operating parameters may include: an operating parameter related to the volume flow and/or mass flow of urea through the urea line; and/or an operating parameter related to the temperature of the urea in the urea line; and/or an operating parameter in relation to the pressure of the urea in the urea line and/or an operating parameter in relation to the pulse duration of a previous injection pulse of the metering element.

The SCR system can be designed such that the parameter values of the one or more operating parameters are determined based on one or more measured values that are recorded at at least one measuring point that is arranged at the inflow to the urea line. On the other hand, the metering element can be arranged on the opposite outlet of the urea line. The parameter values of the one or more operating parameters can thus indicate the operating state of the urea line at the at least one measuring point at the inflow to the urea line (which is spaced from the metering element for metering the amount of urea according to the length of the urea line).

The SCR system may include a pump configured to pump urea into the inflow of the urea line. Furthermore, the SCR system can include a pressure sensor that is set up to record pressure measurements relating to the pressure of urea at a measuring point at the inflow of the urea line. The device can be set up to operate the pump depending on the pressure measured values, in particular to ensure that the pressure of urea at the measuring point has a target pressure value. It can thus be caused that the urea pressure at the inflow of the urea line has a defined target pressure value. So A particularly precise and efficient metering of the amount of urea (if necessary alone) can be effected by the metering element (which is arranged at the outlet of the urea line).

The device is also set up to operate the metering element depending on the determined parameter values of the one or more operating parameters. In particular, a correction of the operation of the dosing element can be effected based on the determined parameter values of the one or more operating parameters, e.g. a correction of one or more injection pulses (such as the frequency, the pulse duration and/or the degree of opening) of the dosing element can be effected.

The device can in particular be set up to determine a correction value based on the determined parameter values of the one or more operating parameters. A correction value can be determined by which the pressure loss of urea between the inflow and the outflow of the urea line is at least partially compensated and/or taken into account. Alternatively or additionally, a correction value can be determined by which the flow resistance of the urea line is at least partially taken into account and/or compensated. Alternatively or additionally, a correction value can be determined by which the temperature dependence of the density and/or the viscosity of the urea is at least partially taken into account and/or compensated for. Alternatively or additionally, a correction value can be determined by which the pressure drop across the dosing element is at least partially compensated for during an injection pulse caused by the dosing element.

The correction value can in particular be designed to at least partially or completely compensate for inaccuracies in the metering of the amount of urea that arise due to the fact that a urea line is arranged between the pump for pumping urea and the metering element for metering the amount of urea. In particular, inaccuracies that arise due to the fact that there is a pressure loss in the pressure of the urea on the urea line (particularly at relatively high volume and/or mass flows of the urea) can be compensated for, so that the pressure at the metering element is lower is than the pressure at the inflow of the urea line, so that a small amount of urea is injected by the metering element per injection pulse (compared to a predetermined target amount). This reduced quantity can be described by the correction value determined on the basis of the parameter values of the one or more operating parameters.

The metering element can then be operated depending on the determined correction value. In particular, the amount of urea injected by the metering element can be adjusted depending on the correction value. In this way, precise dosing of urea can be achieved efficiently in an SCR system.

The device can be set up to determine exhaust gas information in relation to the amount of exhaust gas, in particular in relation to the volume and/or mass flow of exhaust gas, in the exhaust pipe. A target amount of urea can then be determined based on the exhaust gas information, which is to be injected into the exhaust gas line by the metering element, in particular in one or more injection pulses.

The metering element can then be operated depending on the target quantity determined. In particular, the pulse frequency and/or the pulse duration of the one or more injection pulses can be determined based on the determined target quantity. If necessary, the degree of opening of the metering element can be determined for the one or more injection pulses depending on the determined target quantity. In this way, a precise dosage of the amount of urea can be achieved.

The target quantity can be determined under the assumption and/or the metering element can be operated under the assumption that there is a urea pressure at the metering element which corresponds to the urea pressure at the inflow of the urea line. However, this assumption can be incorrect, particularly with relatively high volume and/or mass flows of urea in the urea line, so that the amount of urea actually injected is lower than the target amount.

The device can therefore be set up to correct the target quantity and/or a manipulated variable of the dosing element determined on the basis of the target quantity, in particular using a controller, on the basis of the correction value, in order to determine a corrected manipulated variable. The metering element can then be operated in a particularly precise manner depending on the corrected manipulated variable. The corrected manipulated variable can, for example, display the pulse frequency and/or the pulse duration of the one or more injection pulses of the dosing element. If necessary, the corrected manipulated variable can indicate the degree of opening of the metering element during an injection pulse.

The correction value can therefore be used to adjust the target quantity-based control of the metering element in order to achieve particularly precise urea metering. This allows in particular whose pressure loss on the urea line can be compensated for in an efficient and precise manner.

The device can be set up to determine the correction value based on the determined parameter values of the one or more operating parameters and based on characteristic data. The characteristics may have been determined in advance experimentally and/or analytically and/or through simulations. The characteristic data can each display a correction value for different combinations of parameter values of the one or more operating parameters. By providing and taking key data into account, a particularly efficient and precise dosage of the amount of urea can be achieved.

The device can be set up to determine a corrected manipulated variable based on the determined parameter values of the one or more operating parameters, in particular using a pilot control. The metering element can then be controlled based on the corrected manipulated variable. By using a pilot control, the dosage quantity can be corrected in a particularly dynamic manner.

The device can be set up, based on the determined parameter values of the one or more operating parameters, to determine a reduced amount of urea that was injected into the exhaust pipe by the metering element as part of at least one previous injection pulse. The reduced quantity injected (compared to the determined target quantity) can be indicated by the correction value. The dosing element can then be operated in such a way (depending on the correction value) that the shortfall is at least partially or completely compensated for by a subsequent injection pulse of the dosing element. In this way, a particularly precise dosage of the amount of urea can be achieved.

The parameter values of the one or more operating parameters can be determined at or for a current point in time. The parameter values of the one or more operating parameters can thus relate to the operating state of the urea line and/or the metering element at or before the current point in time. The metering element can then be operated at or after the current time depending on the determined parameter values of the one or more operating parameters. This can be done in a corresponding manner for a sequence of successive (each current) times in order to enable long-term precise operation of the SCR system.

As explained above, parameter values of one or more operating parameters of the metering element can be determined. In particular, the pulse duration of one or more previous injection pulses that were caused by the dosing element before the current point in time can be determined. Based on the pulse duration of the one or more previous injection pulses (i.e. based on the opening time of the dosing element for one or more previous injection pulses), the correction value can be determined, with which the operation of the dosing element can then be adjusted according to the current point in time.

By taking into account the pulse duration of a previous injection pulse, the pressure loss and/or the pressure drop at the metering element that occurs in the course of the previous injection pulse can be taken into account. This pressure loss and/or pressure drop leads to a reduced amount of urea (compared to the actual target value) that is injected as part of the previous injection pulse.

Characteristic data can be determined in advance that shows the pressure loss and/or the shortage as a function of the pulse duration. The characteristic data can be used to determine the reduced amount of urea in the previous injection pulse in an efficient and precise manner based on the pulse duration of a previous injection pulse. The shortfall can then be compensated (at least partially or completely) in a subsequent injection pulse (by adjusting the target value and/or by precontrol).

The pressure drop in the urea pressure at the metering element is typically dependent on the rigidity of the SCR system, in particular on the rigidity of the urea line and/or the metering element. The pressure drop at the metering element can typically only be detected with a time delay (e.g. between 100 and 200 ms) on the pressure sensor of the urea line (in particular on the pressure sensor at the inflow of the urea line). This pressure drop, which is not detected by sensors, leads to a reduced amount of injected urea, which can be at least partially or completely compensated for by the measures described in this document (as part of one or more subsequent injection pulses).

According to a further aspect, an SCR system is described that includes the device described in this document.

According to a further aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described which has the characteristics in the the device described in this document and/or the SCR system described in this document.

According to a further aspect, a method for operating a metering element of an SCR system is described, wherein the SCR system is designed to bring about a selective catalytic reaction of nitrogen oxides in the exhaust gas of an internal combustion engine. The SCR system includes a urea line through which urea is provided to the metering element.

The method includes determining parameter values of one or more operating parameters in relation to the operating state of the urea line and/or the metering element. Furthermore, the method includes operating the metering element depending on the determined parameter values of the one or more operating parameters.

According to a further aspect, a software (SW) program is described. The SW program can be set up to run on a processor (e.g. on a vehicle control unit) and thereby carry out the method described in this document.

According to a further aspect, a storage medium is described. The storage medium may include a SW program configured to be executed on a processor and thereby carry out the method described in this document.

It should be noted that the methods, devices and systems described in this document can be used both alone and in combination with other methods, devices and systems described in this document. Furthermore, any aspects of the methods, devices and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways. Furthermore, features listed in brackets are to be understood as optional features.

• 1 ein beispielhaftes Fahrzeug mit einem SCR-System;
• 2 einen beispielhaften Zusammenhang zwischen der Abgasmenge und der Harnstoffmenge;
• 3a einen beispielhaften Zusammenhang zwischen ein oder mehreren Betriebsparametern der Harnstoff-Leitung und einem Korrekturwert für die Harnstoff-Sollmenge;
• 3b eine beispielhafte Vorrichtung zur Steuerung und/oder Regelung eines Harnstoff-Dosierelements; und
• 4 ein Ablaufdiagramm eines beispielhaften Verfahrens zum Betrieb eines Harnstoff-Dosierelements.

The invention is further described in more detail using exemplary embodiments. Show it

• 1 an example vehicle with an SCR system;
• 2 an exemplary relationship between the amount of exhaust gas and the amount of urea;
• 3a an exemplary relationship between one or more operating parameters of the urea line and a correction value for the target urea quantity;
• 3b an exemplary device for controlling and/or regulating a urea metering element; and
• 4 a flowchart of an exemplary method for operating a urea metering element.

As stated at the beginning, this document deals with the efficient and precise adjustment of the amount of urea in a vehicle's SCR system. In this context shows 1 an exemplary vehicle 100 with an SCR system 120. The SCR system 120 includes a urea container 102, which is designed to hold urea 102, in particular a urea-water mixture. The urea container 102 can be filled with urea 103, for example via a refueling access (not shown).

During operation of the SCR system 120, urea 103 can be pumped out of the urea container 102 by a pump 104 and directed via a urea line 108 to a metering element 112 (e.g. to a valve and/or to an injection nozzle). The urea container 102 with the pump 104 can be arranged in the rear of the vehicle 100, and the metering element 112 can be arranged in the front area (e.g. in the engine compartment) of the vehicle 100. The urea line 108 can thus run from the rear to the front of the vehicle 100.

The metering element 112 can be designed to inject urea 103 into the exhaust line 110 of the vehicle 100, in particular at a point between the NO _x storage catalytic converter 107 and the SCR catalytic converter 109 (in which the selective catalytic reaction to reduce the NO _x molecules in the exhaust gas 111 he follows). In order to eliminate the NO _x molecules from the exhaust gas 111 as completely as possible, a certain amount of urea 103 should be injected into the exhaust gas line 110, depending on the amount of exhaust gas.

2 shows an exemplary relationship 200 between the amount of exhaust gas 201 (eg between the volume and / or mass flow of the exhaust gas 111) and the target amount 202 of urea 103 to be injected. The relationship 200 can be determined in advance experimentally and / or analytically and on a Storage unit (not shown) of the vehicle 100 are stored. A (control) device 101 of the vehicle 100 can be set up by the internal combustion engine (not shown) of the vehicle 100 to determine the amount of exhaust gas 201 generated (eg the exhaust gas mass flow). Furthermore, the device 101 can be set up to determine the target amount 202 of urea 103 to be injected based on the context 200 and the determined exhaust gas amount 201. The metering element 112 and/or the pump 104 can then be operated to cause the determined target amount 202 of urea 103 to be injected into the exhaust line 110.

The SCR system 120 may include a pressure sensor 105 that is configured to determine pressure measurements related to the pressure within the urea line 108. The pressure measurement values can be determined at a measuring point that is arranged in the immediate vicinity of the pump 104 and/or at the inflow to the urea line 108. The (control) device 101 can be set up to operate the pump 104 depending on the pressure measured values of the pressure sensor 105, for example to cause the urea pressure at the measuring point to reach a specific target pressure value (approximately 6 bar). having. The metering of the injected amount of urea 103 can then possibly be effected independently of the operation of the pump 104, possibly solely by controlling and / or regulating the metering element 112.

The SCR system 120 may further include a temperature sensor 106 that is configured to capture temperature measurements related to the temperature of the urea 103 at a measurement point. The measuring point can be arranged at the inflow to the urea line 108. The one or more temperature measurements can be taken into account when metering the amount of urea injected and/or when operating the pump 104.

It can be observed that the actual amount of urea 103 actually injected by the metering element 112 deviates from the target amount 202 to be injected during operation of the SCR system 120. The deviation can be different depending on the operating state of the SCR system 120, in particular depending on the operating state of the urea line 108. In particular, it can be observed that as the urea volume flow in the urea line 108 increases, the actual quantity increasingly lies below the target quantity. Furthermore, it can be observed that the extent of the deviations between the actual amount and the target amount depends on the temperature measurement values in relation to the temperature of the urea 103 at the inflow to the urea line 108.

• • der Volumenstrom an Harnstoff 103 durch die Harnstoff-Leitung 108, der z.B. auf Basis der Pump-Leistung der Pumpe 104 ermittelt werden kann;
• • die Temperatur des Harnstoffs 103 in der Harnstoff-Leitung 108, die z.B. auf Basis der Temperatur-Messwerte des Temperatursensors 106 erfasst werden kann; und/oder
• • der Druck in der Harnstoff-Leitung 108, der z.B. anhand der Druck-Messwerte des Drucksensors 105 ermittelt werden kann.

The operating state of the urea line 108 can be described by parameter values for one or more operating parameters 301 (see 3a) . Example operating parameters 301 are,

• • the volume flow of urea 103 through the urea line 108, which can be determined, for example, based on the pump performance of the pump 104;
• • the temperature of the urea 103 in the urea line 108, which can be detected, for example, based on the temperature measured values of the temperature sensor 106; and or
• • the pressure in the urea line 108, which can be determined, for example, based on the pressure measured values of the pressure sensor 105.

In advance, characteristic data 300 can be determined analytically and/or experimentally and/or through simulations, which establish the relationship between the operating state of the urea line 108 (which can be described by parameter values for the one or more operating parameters 301) and a correction value 302 for correction display the target amount of 202 of urea 103. The identification data 300 can be stored on a storage unit of the vehicle 100.

The (control) device 101 can be set up to determine parameter values for one or more operating parameters 301 of the urea line 108 (e.g. based on the temperature measurement value, based on the pressure measurement value and/or based on the pump performance of the pump 104). The device 101 can also be set up to correct the correction value 302 for correcting the target amount 202 of urea 103 that is to be injected into the exhaust gas output 110, based on the characteristic data 300 and based on the determined parameter values for the one or more operating parameters 301 of the urea -Line 108 to be determined. The metering element 112 can then be operated depending on the target quantity 202 and depending on the determined correction value 302. In this way, the accuracy of the dosage of the injected amount of urea can be increased efficiently.

3b shows an exemplary device 320 for controlling and/or regulating the metering element 112. Based on the exhaust gas quantity 201, a target quantity 202 of urea 103 to be injected can be determined. To implement a control loop, the target quantity 202 can be compared with a recorded actual quantity 314 in order to determine a control error 311, which is converted by a controller 310 into a controller manipulated variable 315 for operating the dosing element 112. The actual amount 314 of injected urea 103 can be determined based on the pump performance of the pump 104 accumulated over time.

The device 320 can further include a correction unit 312, which is set up to determine a correction value 302 using the characteristic data 300 based on the parameter values for the one or more operating parameters 301. The correction value 302 can be used to correct the controller manipulated variable 315. The correction value 302 can cause an offset and/or a scaling of the controller manipulated variable 315 in order to determine a corrected manipulated variable 316. The metering element 112 can then be operated with the corrected manipulated variable 316.

• • ein Pulsdauer eines Injektionspulses des Dosierelements 112;
• • eine Pulsfrequenz von Injektionspulsen;
• • eine Öffnungszeitdauer, in der das Dosierelement 112 geöffnet ist; und/oder
• • ggf. einen Öffnungsgrad, mit dem das Dosierelement 112 geöffnet ist.

A control variable 315, 316 for the metering element 112 can display values for one or more control parameters of the metering element 112. Examples of control parameters are:

• • a pulse duration of an injection pulse of the dosing element 112;
• • a pulse frequency of injection pulses;
• • an opening period in which the metering element 112 is open; and or
• • If necessary, an opening degree with which the metering element 112 is open.

The manipulated variable 316 for operating the metering element 112 can thus be adjusted directly by a correction value 302 (e.g. as part of a pilot control). In this way, a particularly precise dosage of the amount of urea can be achieved.

• • der Durchflusswiderstand der SCR Dosierleitung 108 in Abhängigkeit des Massenstroms und/oder der Temperatur;
• • eine dynamische Viskosität des Harnstoffs 103 in Abhängigkeit von der Temperatur (z.B. laminare Strömung in der Dosierleitung 108 vs. turbulente Strömung im Spritzloch des Injektors 112);
• • die Dichte des Harnstoffs 103 in Abhängigkeit von der Temperatur; und/oder
• • eine Abhängigkeit der dosierten Menge pro Injektionsschuss des Dosierelements 112 von der Steifigkeit und/oder der Elastizität des Dosierelements 112 und/oder der Dosierleitung 108 (Druckabfall während des Injektionsschusses).

As already explained above, dosage deviations in relation to the dosage of urea 103 could be detected. In particular, the following causes for the dosage quantity deviations were identified:

• • the flow resistance of the SCR metering line 108 depending on the mass flow and/or the temperature;
• • a dynamic viscosity of the urea 103 depending on the temperature (eg laminar flow in the metering line 108 vs. turbulent flow in the spray hole of the injector 112);
• • the density of urea 103 as a function of temperature; and or
• • a dependence of the dosed quantity per injection shot of the dosing element 112 on the stiffness and/or the elasticity of the dosing element 112 and/or the dosing line 108 (pressure drop during the injection shot).

The physical conditions of the SCR system 120 can be recorded via test bench and/or driving tests and mapped in characteristic data 300. Based on this, correction variables 302 can then be determined to reduce the dosage quantity deviations.

The correction can be effected by a function and/or calibration. For example, a preventive correction of the control signal 316 of the metering element 112 can be effected as part of a precontrol. Alternatively or additionally, as part of post-processing, a back calculation of previous events (injection pulses) and a correction in a subsequent event (injection pulse) of the dosing element 112 can be effected. A correction of the shortfall delta can be effected based on the existing physical conditions. The correction can be calculated as a correction factor based on a reference variable 315.

4 shows a flowchart of a (possibly computer-implemented) method 400 for operating a metering element 112, for example an injection nozzle, of an SCR system 120 for effecting a selective catalytic reaction of nitrogen oxides in the exhaust gas 111 of an internal combustion engine (in particular a diesel engine). The SCR system 120 includes a urea line 108, via which urea 103 is provided to the metering element 112. Furthermore, the metering element 112 is designed to inject urea 103 from the urea line 108 into the exhaust line 110 with the exhaust gas 111 of the internal combustion engine. The dosing element 112 can cause injection pulses.

The method 400 includes determining 401 parameter values of one or more operating parameters 301 in relation to the operating state of the urea line 108 and/or the metering element 112. The parameter values of the one or more operating parameters 301 can describe the current operating state of the urea line 108 , in particular with regard to the volume and / or mass flow of the urea 103 flowing through the urea line 108. Alternatively or additionally, the one or more operating parameters 301 can describe the pulse duration of one or more previous injection pulses that (before the current point in time) were caused by the metering element 112.

The method 400 further includes operating 402 the dosing element 112 (at the current time) as a function of the determined parameter values of the one or more operating parameters 301. In particular, a correction of the injection quantity caused by the dosing element 112 can be effected (which is, for example, by a or multiple injection pulses that are effected on or after the current time).

Through the measures described in this document, precise metering of urea 103 in an SCR system 120 can be effected in an efficient manner.

The present invention is not limited to the exemplary embodiments shown. In particular, it should be noted that the description and the figures are only intended to illustrate the principle of the proposed methods, devices and systems by way of example.

Reference symbol list

100

vehicle

101

(Control) device

102

Urea tank

103

urea

104

pump

105

Pressure sensor

106

Temperature sensor

107

NO _x storage catalytic converter

108

Urea line

109

SCR catalyst

110

Exhaust pipe

111

exhaust

112

Dosing element (injector)

120

SCR system

200

Characteristics

201

exhaust gas quantity

202

Urea target amount

300

Characteristics

301

Operating parameters (of the urea line)

302

Correction value

310

Regulator

311

Rule error

312

Correction unit

314

Actual value of the amount of urea

315

Controller manipulated variable

316

corrected manipulated variable

400

Method for operating the metering element

401, 402

Procedural steps

Claims (12)

Device (101, 320) for operating a metering element (112) of an SCR system (120) for causing a selective catalytic reaction of nitrogen oxides in an exhaust gas (111) of an internal combustion engine; wherein the SCR system (120) comprises a urea line (108) via which urea (103) is provided to the metering element (112); wherein the metering element (112) is designed to inject urea (103) from the urea line (108) into an exhaust line (110) with the exhaust gas (111) of the internal combustion engine; wherein the device (101, 320) is set up, - to determine parameter values of one or more operating parameters (301) in relation to an operating state of the urea line (108) and/or the metering element (112); and - to operate the metering element (112) depending on the determined parameter values of the one or more operating parameters (301). Device (101, 320) according to Claim 1 , wherein the device (101, 320) is set up to - determine exhaust gas information in relation to an exhaust gas quantity (201) of exhaust gas (111) in the exhaust gas line (110); - based on the exhaust gas information, to determine a target amount (202) of urea (103) which is to be injected into the exhaust gas line (110) by the metering element (112), in particular in an injection pulse; and - to operate the metering element (112) depending on the determined target quantity (202). Device (101, 320) according to Claim 2 , wherein the device (101, 320) is set up to - determine a correction value (302) based on the determined parameter values of the one or more operating parameters (301); - to correct the target quantity (202) and/or a manipulated variable (315) determined on the basis of the target quantity (202), in particular using a controller (310), on the basis of the correction value (302) in order to produce a corrected manipulated variable (316) to determine; and - to operate the metering element (112) depending on the corrected manipulated variable (316). Device (101, 320) according to one of the preceding claims, wherein the device (101, 320) is set up - to determine a correction value (302) based on the determined parameter values of the one or more operating parameters (301) and based on characteristic data (300); and - to operate the dosing element (112) as a function of the determined correction value (302), in particular to adapt an injection pulse of the dosing element (112) as a function of the ascertained correction value (302). Device (101, 320) according to Claim 4 , wherein - the characteristics (300) were determined in advance experimentally and/or analytically and/or through simulations; and/or - the characteristic data (300) each display a correction value (302) for different combinations of parameter values of the one or more operating parameters (301). Device (101, 320) according to one of the preceding claims, wherein the one or more operating parameters (301) comprise, - an operating parameter (301) in relation to a volume flow and/or a mass flow of urea (103) through the urea line (108); and or - an operating parameter (301) in relation to a temperature of the urea (103) in the urea line (108); and or - an operating parameter (301) in relation to a pressure of the urea (103) in the urea line (108); and or - an operating parameter (301) in relation to a pulse duration of a previous injection pulse of the dosing element (112). Device (101, 320) according to one of the preceding claims, wherein - the SCR system (120) is designed such that the parameter values of the one or more operating parameters (301) are determined based on one or more measured values that are recorded at at least one measuring point, which is at an inflow to the urea line (108) is arranged; and - The metering element (112) is arranged at an opposite outlet of the urea line (108). Device (101, 320) according to one of the preceding claims, wherein the device (101, 320) is set up - to determine a correction value (302) based on the determined parameter values of the one or more operating parameters (301), through which - at least partially compensating for a pressure loss of urea (103) between an inflow and an outflow of the urea line (108); and or - at least partially a flow resistance of the urea line (108) is taken into account; and or - a temperature dependence of a density and/or a viscosity of the urea (103) is at least partially taken into account; and or - at least partially compensating for a pressure drop at the metering element (112) during an injection pulse caused by the metering element (112); and - to operate the metering element (112) depending on the determined correction value (302). Device (101, 320) according to one of the preceding claims, wherein the device (101, 320) is set up - to determine a corrected manipulated variable (316) based on the determined parameter values of the one or more operating parameters (301), in particular using a pilot control; wherein the corrected manipulated variable (316) indicates in particular a pulse frequency, a pulse duration and/or a degree of opening of one or more injection pulses of the metering element (112) for injecting urea (103); and - to control the metering element (112) based on the corrected manipulated variable (316). Device (101, 320) according to one of the preceding claims, wherein the device (101, 320) is set up - based on the determined parameter values of the one or more operating parameters (301), to determine a minimum amount of urea (103) that was injected into the exhaust pipe (110) by the metering element (112) as part of a previous injection pulse; and - to operate the metering element (112) in such a way that the shortage is at least partially or completely compensated for by a subsequent injection pulse of the metering element (112). Device (101, 320) according to one of the preceding claims, wherein - the SCR system (120) comprises a pump (104) which is designed to pump urea (103) into an inflow of the urea line (108); - the SCR system (120) comprises a pressure sensor (105) which is set up to record pressure measurement values in relation to a pressure of urea (103) at a measuring point at the inflow of the urea line (108); and - the device (101, 320) is set up to operate the pump (104) depending on the pressure measured values, in particular to ensure that the pressure of urea (103) at the measuring point has a target pressure value. Method (400) for operating a metering element (112) of an SCR system (120) for effecting a selective catalytic reaction of nitrogen oxides in an exhaust gas (111) of an internal combustion engine; wherein the SCR system (120) comprises a urea line (108) via which urea (103) is provided to the metering element (112); wherein the metering element (112) is designed to inject urea (103) from the urea line (108) into an exhaust line (110) with the exhaust gas (111) of the internal combustion engine; wherein the method (400) comprises, - Determining (401) parameter values of one or more operating parameters (301) in relation to an operating state of the urea line (108) and/or the metering element (112); and - operating (402) the metering element (112) depending on the determined parameter values of the one or more operating parameters (301).

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