AT520896A1 - Method for functional testing of an exhaust aftertreatment system - Google Patents

Abstract

The invention relates to a method for functional testing of an exhaust aftertreatment system of an internal combustion engine, wherein a measurement window is determined by calculating the amount of energy converted by the internal combustion engine, wherein the measurement window starts at a starting point and ends at a certain amount of energy at an end point, wherein during the measurement window at a In the course of the exhaust aftertreatment system, the total mass of at least one exhaust gas component is determined, wherein at least one on the function of the exhaust aftertreatment plant aufschlussgebender control value including the determined mass of the at least one exhaust gas component is determined, wherein the at least one control value is compared with at least one threshold for assessing the validity of the recorded measurement window, at least one validity parameter is taken into account, wherein, if appropriate, a status information about the footing is provided output of the exhaust aftertreatment system is output and / or stored, and wherein the steps for further measurement windows are repeated.

Description

Method for functional testing of an exhaust aftertreatment system

The invention relates to a method according to the preamble of the independent

Claim.

From the prior art, different methods for functional testing of exhaust aftertreatment systems are known. For example, methods are known in which after the achievement of predefined conditions, so-called "enabling conditions", measured values are recorded. Thus, in such conventional methods, a measurement window begins as soon as these conditions are reached. A disadvantage of this method, however, is that the recording of measured values is stopped immediately and the measurement window ends when the predetermined conditions are not met even for a short time.

The object of the invention is to overcome the disadvantages of the prior art. In particular, it is an object of the invention to provide a robust method by which the number of valid measurement windows can be increased.

The object of the invention is achieved in particular by the features of the independent claim.

The invention relates to a method for functional testing of a

Exhaust after-treatment system of an internal combustion engine, in particular an exhaust aftertreatment component, such as an SDPF or SCR catalyst, the method comprising the steps of determining a measurement window by calculating the amount of energy converted by the internal combustion engine, the measurement window starting at a starting point and at a certain calculated amount of energy ending an endpoint, determining the mass of at least one exhaust gas component occurring overall during the measurement window at one point in the course of the exhaust aftertreatment system, determining at least one information about the function of the exhaust aftertreatment system giving control value including the determined mass of the at least one exhaust gas component, comparing the at least one control value at least one limit value, assessing the validity of the recorded measurement window taking into account at least one validity parameter, possibly Ausg repeating and / or storing status information on the function of the exhaust aftertreatment system, repeating the steps for further measurement windows, which are lined up sequentially and thereby form a first measurement window row, the starting point of the further measurement window of the first measurement window row corresponds in particular to the end point of the preceding measurement window of the first measurement window row.

At the beginning of the process, the measuring window length can be determined by determining an amount of energy converted by the internal combustion engine. The measurement window begins at a starting point and ends when the predetermined amount of energy has been reached at an endpoint. For this purpose, if appropriate, the engine power during the measurement, in particular during the measurement window, integrated as long as the predetermined amount of energy has not yet been reached. Thus, the engine power over the entire window length can be integrated. Once the predetermined amount of energy is reached, the measurement window may terminate at an endpoint. The measuring window length can thus correspond to a predetermined amount of energy. During the measurement window may be at one point in the course of

Exhaust after-treatment system the total mass of at least one exhaust gas component can be determined or determined. In the context of the present disclosure, a position in the course of the exhaust aftertreatment system is understood to mean a position according to the engine of the internal combustion engine.

To determine at least one control value, the specific mass of at least one exhaust gas component can be included. This means that optionally at least one control value is calculated from recorded values, in particular measured values and / or specific masses, which permits and / or gives information about the function of the exhaust aftertreatment system. Optionally, it is provided that a control value includes a plurality of recorded values, in particular a plurality of measured values, and / or a specific mass at one point in the course of the exhaust aftertreatment system.

Subsequently, the at least one control value can be compared with at least one limit value. The limit may be a predetermined value. In particular, the limit value is determined from a characteristic curve characteristic of the internal combustion engine. This particular map limit may then be optionally multiplied by correction factors. By comparing the control value with the limit value, a statement about the functionality of the exhaust aftertreatment system can be made. Depending on

Control value and limit, an exhaust aftertreatment system can be considered functional if the control value is above or below the limit value.

In order to assess the validity of the measurement window, at least one validity parameter is used if necessary.

Optionally, the status information for the function of the exhaust aftertreatment system is output and / or stored in a further step. If the exhaust aftertreatment system is assessed as "non-functional", it can be provided, in particular, that the status information takes place by switching on the MILLamp ("malfunction indicator light"). This allows the driver of the motor vehicle on the functionality of the

Exhaust gas after-treatment system to be informed. If necessary, the

Status information can also be stored in a storage system of the internal combustion engine and / or a motor vehicle.

As soon as the first measuring window reaches its end point, a further measuring window, in particular adjoining the first measuring window, may optionally be recorded. For this purpose, the steps of the method can be repeated. Optionally, it is provided that the first and optionally further rows of measurement windows are formed and / or are formed by the sequentially lined-up measurement windows. The starting points of the further measurement window of the first measurement window row correspond in particular to the end points of the preceding measurement window of the first measurement window row. This means, for example, that the starting point of the second measurement window of the first measurement window row corresponds to the end point of the first measurement window of the first measurement window row.

If appropriate, it is provided that the method steps of the method follow one another as described above.

Optionally, it is provided that a second measurement window row is formed whose measurement windows are offset by a specific offset value, in particular by a certain amount of energy, relative to the first measurement window row, in particular with respect to the measurement windows of the first measurement window row.

Optionally, it is provided that a second measurement window row is formed which is offset by a specific offset value from the measurement windows of the first measurement window row and which optionally has sequentially lined-up measurement windows. This means, for example, that the first measuring window of the second measuring window row has a starting point which is shifted by a specific offset value relative to the starting point of the first measuring window of the first measuring window row. The offset value preferably corresponds to a certain amount of energy.

Optionally, it is provided that at least one further measuring window row is formed whose measuring windows are offset by a specific offset value, in particular by a certain amount of energy, from another row of measuring windows, in particular with respect to the measuring windows of another row of measuring windows.

Optionally, it is provided that a further measurement window row is formed which is offset by a specific offset value from the measurement windows of another measurement window row and which optionally comprises sequentially lined measurement windows. This means, for example, that the starting point of the first measurement window of another measurement window row is offset by the offset value to the starting point of the first measurement window of another, in particular the preceding, measurement window row.

Optionally, it is provided that all measurement windows of a measurement window row or all measurement windows of all measurement window rows are defined by the same amount of energy.

In particular, it can be determined that the lengths of the measurement windows, the so-called measurement window lengths, a measurement window row or all measurement window rows are substantially the same.

Optionally, it is provided that the lengths of the measuring window of a

Messfensterreihe are different and / or determined by different predefined amounts of energy.

Optionally, it is provided that the lengths of the measuring window of a

Measurement window row are substantially the same, but the lengths of the measuring windows of another range of measurement windows are different. This means that the measurement window lengths of different measurement window rows are determined by different predefined amounts of energy.

Optionally, it is provided that the starting points of the measurement windows of one measurement window row are offset from the starting points of the measurement windows of another measurement window row by the, in particular equal, offset value, and / or that the starting points of the measurement windows of all measurement window rows are opposite the starting points of the measurement windows of all other measurement window rows Offset values are offset.

If appropriate, it is provided that the determination of the offset value and / or the offset values Vw takes place according to the following rule:

where Vw is the offset value, where EEng is the converted energy amount of the internal combustion engine, in particular the amount of energy of a measurement window, and where n is the number of measurement window rows.

Optionally, it is provided that the offset value corresponds to 1 / n of the converted amount of energy of the internal combustion engine, in particular the amount of energy determining the measuring window length, where n is the number of measurement window rows, or that the offset value in particular 1/2 of the converted amount of energy of the internal combustion engine, in particular the Measuring window length-determining amount of energy corresponding to 2 rows of measurement windows, or that the offset value in particular 1/3 of the converted amount of energy of the internal combustion engine, in particular the amount of energy determining the measuring window length corresponds to 3 rows of measurement windows, or that the offset value in particular 1/4 of the converted amount of energy of the internal combustion engine, in particular the amount of energy determining the measuring window length, corresponds to 4 rows of measuring windows, or that the offset value in particular 1/5 of the converted amount of energy of the internal combustion engine, in particular bes the measuring window length bes in the case of 5 rows of measuring windows, or that the offset value corresponds in particular to 1/6 of the converted energy quantity of the internal combustion engine, in particular the amount of energy determining the measuring window length, in the case of 6 measuring window rows, or that the offset value

in particular 1/7 of the amount of energy converted of the internal combustion engine, in particular the amount of energy determining the measuring window length, corresponds to 7 measurement window rows, or that the offset value in particular 1/8 of the converted energy amount of the internal combustion engine, in particular the amount of energy determining the measuring window length corresponds to 8 measurement window rows, or the offset value corresponds in particular to 1/9 of the converted energy quantity of the internal combustion engine, in particular the amount of energy determining the measuring window length, with 9 measuring window rows, or that the offset value corresponds in particular to 1/10 of the converted energy quantity of the internal combustion engine, in particular the amount of energy determining the measuring window length, for 10 measuring window rows.

The offset value can be defined in particular by a converted amount of energy. Preferably, the offset value corresponds to a fraction of the amount of energy converted to determine the measuring window length

Internal combustion engine. It is preferably provided that the offset value has a value which is in the range of half the amount of energy converted to 1/10 of the amount of energy converted.

In particular, it is provided that the offset value corresponds to half the amount of energy converted when two rows of measurement windows are recorded. This means in particular that the starting points of the measuring windows of the second row of measuring windows are offset by half the amount of energy converted by the internal combustion engine during a measuring window, in particular the amount of energy determining the measuring window length, compared with the starting points of the measuring windows of the first measuring window row.

Optionally, it is provided that the amount of energy converted by the internal combustion engine is calculated by means of the rotational speed of the internal combustion engine, in particular the engine speed, NEng and the injected fuel quantity MfFulInj, and / or that the calculation of the amount of energy converted by the internal combustion engine takes place according to the following procedure:

where EEng is the amount of energy converted by the internal combustion engine during a measurement window, where PwrEng is the engine power, where NEng is the engine speed, and TqEng is the engine torque.

Preferably, the converted amount of energy of the internal combustion engine is continuously calculated and / or recorded. For determining the measuring window length, the calculated and / or recorded converted energy quantity and / or motor power, in particular during a measuring window, can be integrated. For example, a measurement window begins at a start point and ends after reaching a certain predefined converted amount of energy at an endpoint. This means, for example, that the measuring window ends as soon as a predetermined amount of energy has been converted by the internal combustion engine.

If appropriate, it is provided that measured values of at least one sensor, in particular measured values of at least one NOx sensor and the exhaust gas volume flow, are used for determining the total mass of an exhaust gas component during the measurement window, and that the at least one sensor is in the course of the exhaust aftertreatment system, in particular before the SCR system and / or after the SCR system. For the determination of the total mass of at least one

Exhaust gas component during the measuring window, measured values of sensors and / or data can be used. The measured values of at least one NOx sensor and the exhaust gas volume flow are preferably used to determine the total mass of an exhaust gas component. The at least one sensor can be arranged in the course of the exhaust aftertreatment system. The various data may, in particular, be engine data such as, in particular, the injection quantity, the air quantity or the like, and / or values calculated from engine data.

Optionally, it is provided that the determination of the total mass of an exhaust gas component takes place during the measurement window at a point in the course of the exhaust aftertreatment system according to the following rule:

where M_win_i the total mass of the exhaust gas component i. during the measuring window, where Mf_i is the mass flow or the mass flow of the exhaust gas component i. where Conc_i is the concentration, the exhaust gas component i. in the mass flow or in the mass flow of the exhaust gas, where MfExh is the mass flow or the mass flow of the exhaust gas, wherein Mmol_i is the molar mass of the exhaust gas component i. and MmolExhGas is the molar mass of the exhaust gas.

In order to determine the mass flow or the mass flow of the at least one exhaust gas component, the concentration of the at least one exhaust gas component in the exhaust gas volumetric flow, the exhaust gas volumetric flow, the molar mass of the at least one exhaust gas component and the molar mass of the exhaust gas are preferably used. In order to determine the total mass of at least one exhaust gas component, the determined mass flow or mass flow is preferably integrated over the measuring window length.

The total mass of the exhaust gas component NO x is preferably determined by the calculation of the mass flow or the mass flow of the exhaust gas components NO and NO 2 and is preferably calculated as shown below:

wherein M_win_NOx is the total mass of the exhaust gas component NOx during the measurement window, where Mf_NOx is the mass flow or mass flow of the exhaust gas component NOx, where Conc_NO is the concentration of the exhaust gas

Exhaust gas component NO in the mass flow or in the mass flow of the exhaust gas, wherein Conc_NO2 is the concentration of the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas, wherein MfExh is the mass flow or the mass flow of the exhaust gas, wherein Mmol_NO is the molar mass of the exhaust gas component NO .

where Mmol_NO2 is the molar mass of the exhaust gas component NO2, and MmolExhGas is the molar mass of the exhaust gas.

If appropriate, it is provided that the determination of a control value KontrollSCR Eff, which permits an explanation of the function of the exhaust aftertreatment system, takes place according to the following rule:

where NOxEff sensor is the Vüx conversion rate or the efficiency value of the SCR system determined from the measured values during the measurement window, where M_win_NOx_dwsSCR determines the total mass of the exhaust gas component NOx after the exit from the SCR, determined from measured values during the measurement window. System, which may be determined according to the following rule:

wherein M_win_NOx_dwsSCR is the total mass of the exhaust gas component NOx after exiting the SCR system during the measurement window, where Mf_NOx_dwsSCR is the mass flow or mass flow of the exhaust gas component NOx after exiting the SCR system, where Conc_NO_dwsSCR is the concentration of the exhaust gas component NO in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, wherein Conc_NO2_dwsSCR is the concentration of the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, wherein Mmol_NO the molar mass of the

Exhaust gas component NO, where Mmol_NO2 is the molar mass of the exhaust gas component NO2, where MfExh is the mass flow or mass flow of the exhaust gas, where MmolExhGas is the molar mass of the exhaust gas, where M_win_NOx_usSCR the total mass of the exhaust gas component determined during the measurement window from measured values NOx before entering the SCR system, which may be determined according to the following regulation:

wherein M_win_NOx_usSCR is the total mass of the exhaust gas component NOx before entering the SCR system during the measurement window, where Mf_NOx_usSCR is the mass flow or mass flow of the exhaust gas component NOx before entering the SCR system, where Conc_NO is the concentration of the exhaust gas component NO in the mass flow or mass flow of the exhaust gas before entering the SCR system, wherein Conc_NO2 is the concentration of the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas before entering the SCR system, wherein Mmol_NO the molar mass of the exhaust gas component NO, where Mmol_NO2 is the molar mass of the exhaust gas component NO2, where MfExh is the mass flow or mass flow of the exhaust gas, where MmolExhGas is the molar mass of the exhaust gas, NOxEff model representing the modeled NOx conversion rate and the modeled efficiency value of the SCR System during the measurement window, where M_win_NOx_dwsSCR_model modeled during the measurement window, in total cumulative mass of the exhaust gas component NOx after exiting the SCR system, and where ControlSCR Eff is the control value based on the determined efficiency values.

For the calculation of the control value KontrollSCR Eff, the total mass of the exhaust gas component NOx after and before the SCR system is preferred

used. In this case, the occurring masses of the at least one exhaust gas component are preferably determined on the one hand based on recorded measured values and on the other hand based on modeled values. The modeled values can be determined, for example, using a catalyst model which calculates the progressing reactions. For example, it is also possible that the modeled values are determined using simple model equations.

In the present disclosure, the concentration of NO and the concentration of NO 2 are determined from the calculated ratio of NO to NO 2 and the measured concentration of NO x.

If appropriate, it is provided that the determination of a control value KontrollNox dws, which allows an explanation of the function of the exhaust aftertreatment system, according to the following rule:

where Mf_NOx_dwsSCR is the mass flow or mass flow of the exhaust gas component NOx after exiting the SCR system, where Conc_NO_dwsSCR is the concentration of the exhaust gas component NO in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, where Conc_NO2_dwsSCR is the concentration the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, where Mmol_NO is the molar mass of the exhaust gas component NO, where Mmol_NO2 is the molar mass of the exhaust gas component NO2, where MfExh is the mass flow or the mass flow of the Exhaust gas is, where MmolExhGas is the molar mass of the exhaust gas, and wherein KontrollNOxdws is the control value, which is based on the determined from measured values total mass of the exhaust gas component NOx after exiting the SCR system.

Preferably, the total mass of the exhaust gas component NOx is used for the calculation of the control value KontrollNOxdws. Optionally, it is provided that the total occurring masses of the exhaust gas components NO and NO2 during the measurement window are used to determine the total mass of the exhaust gas component NOx during a measurement window.

If necessary, the control value has the unit mg / kWh. In this case, the NOx mass used for the calculation of the control value can be related to the energy quantity of the measuring window according to the SCR system.

If necessary, it is provided that a limit value LimitSCR Eff is used to compare the control value KontrollSCR Eff, wherein the limit value LimitSCR Eff is a predetermined efficiency value of the exhaust aftertreatment system and / or a predetermined efficiency value of an exhaust aftertreatment component, in particular an SCR system, and / or that for the comparison of the control value KontrollNOx dws a limit value LimitNOx dws is used, wherein the limit value LimitNOx dws a predetermined, total mass of an exhaust gas component, in particular the total mass of NOx after the last exhaust gas component, in particular the SCR system, the

Exhaust after-treatment system is.

To assess the functionality of the exhaust aftertreatment system limits can be used. These limits are preferably a predetermined efficiency value of the exhaust aftertreatment system, a predetermined efficiency value of an exhaust aftertreatment component, and / or a predetermined total mass of an exhaust gas component at a particular location of the exhaust aftertreatment system.

Optionally, it is provided that the measurement window is defined as valid if the at least one validity parameter is within a validity range for a certain duration during the measurement window, and / or if the at least one validity parameter remains valid for a certain period of time of the measurement window is outside a validity range, and / or that the measurement window is defined as invalid if a predetermined

Number of out of scope, underflow, and / or scope violations is exceeded.

By way of example, parameters such as the engine speed, the introduced fuel quantity, the engine torque, the calculated engine power or the like can be used as validity parameters. The measurement window may be invalid, for example, if the calculated engine power is highly transient and, as a result, the at least one validity parameter does not lie within the defined validity range for the predefined duration.

As a result, a measurement window can also be defined as valid if the at least one validity parameter is outside the validity range a few times and / or the at least one validity parameter is outside the validity range for a certain time. Optionally, it is provided that a measurement window is defined as invalid if a number of predetermined validity area violations, validity area overruns and / or validity area underruns were exceeded. If necessary, it is defined that if a validity parameter during a measurement window is below the validity range or exceeds a validity range violation.

Optionally, as a validity parameter, the averaged SCR catalyst temperature, the stored amount of reducing agent, in particular the stored amount of NH3, in the SCR catalyst and / or in the SCR model, the mass flow of reducing agent, in particular the mass flow of NH3, the NOx Concentration before the SCR system, in particular the NOx concentration before the SCR catalyst, the mass flow or the mass flow of the exhaust gas, the temperature before the SCR system, in particular the temperature before the SCR catalyst, the ambient pressure, the Ambient temperature and / or the like are used.

Optionally, it is provided that the function of the exhaust aftertreatment system is defined as functional if the control value KontrollSCR Eff is above the limit LimitSCR Eff and the measurement window is defined as valid, and / or that the function of the exhaust aftertreatment system is defined as functional, if the control value KontrollNoxdws is below the LimitNox dws limit and the measurement window is defined as valid.

The function of the exhaust aftertreatment system is preferably classified as functional if the control value KontrollSCR Eff is above the limit value LimitSCR Eff and the measurement window is assessed as valid. In particular, this means that, if the exhaust aftertreatment system is classified as functional, the efficiency of the exhaust gas component SCR is above the limit efficiency of the exhaust gas component SCR and thus the exhaust gas component NOx is sufficiently reduced. Preferably, the at least one validity parameter must also be in the validity range for the predetermined duration.

The function of the exhaust aftertreatment system is preferably classified as functional if the control value KontrollNoxdws is below the limit value LimitNoxdws and the measurement window is defined as valid. In particular, this means that, if the exhaust aftertreatment system is classified as functional, the total occurring mass of the exhaust gas component NOx after the exhaust gas component SCR is below the predefined limit and the at least one validity parameter is also in the validity range for the predetermined duration.

If necessary, it is provided that the functionality of the

Exhaust after-treatment system is output and / or stored when the ControlSCR Eff control value is above or below the LimitSCR Eff limit and the measurement window is valid and / or the ControlNox dws control value is above or below the LimitNoxdws limit and the measurement window is valid becomes.

If appropriate, it is provided that the exhaust aftertreatment system is judged to be functional if the measurement window is defined as valid and the control value KontrollSCR Eff is above the limit value LimitSCR Eff, whereby the so-called diagnostic efficiency function is fulfilled, or the control value KontrollNox dws below the limit value LimitNox dws lies, whereby the so-called DiagnoseMengenfunktion is met.

If appropriate, it is provided that the exhaust aftertreatment system is judged to be functional if the measurement window is defined as valid and the control value KontrollSCR Eff is above the limit value LimitSCR Eff, whereby the so-called diagnostic efficiency function is fulfilled, and the control value KontrollNox dws below the limit value LimitNox dws lies, whereby the so-called DiagnoseMengenfunktion is met.

Optionally, it is provided that the exhaust aftertreatment system is classified as not functioning and / or the status information is output and / or stored when one of the two diagnostic functions is not met.

If appropriate, it is provided that the exhaust aftertreatment system is only classified as non-functional and / or the status information is output and / or stored only if both diagnostic functions are not fulfilled.

Optionally, it is provided that the exhaust aftertreatment system is only classified as functional and / or the status information is only output and / or stored when both diagnostic functions are met.

If necessary, several measuring windows are used to assess the functionality of the exhaust aftertreatment system. It can be provided that the functional efficiency is output and / or stored only if a diagnostic function and / or both diagnostic functions deliver the same result with respect to functionality for a predetermined number of successive measurement windows.

If appropriate, it is provided that the different diagnostic functions for different internal combustion engines can be used differently for the assessment of the functionality of the exhaust aftertreatment system. In particular, the diagnostic functions can be used specifically in different operating areas. As a result, the robustness or the stability of the method can optionally be increased. Furthermore, this can increase the number of valid measurement windows.

For example, it may be provided that in internal combustion engines, which have a high concentration of the exhaust gas component NOx after the engine, only the diagnostic quantity function is used to assess the functionality of the exhaust aftertreatment system. For the assessment of the functionality can thus be the total mass of the

Exhaust gas component NOx before the exhaust system and / or before the exhaust gas component, in particular in front of the SCR system, are neglected, since only the total mass of the exhaust gas component after the exhaust system and / or after the exhaust gas component is required.

Optionally, it is provided that the status information for the function of the exhaust aftertreatment system by means of a MIL lamp "Malfunction Indicator Light -Motor control lamp" of a vehicle is issued, whereby the driver is informed about the status of the functionality of the exhaust aftertreatment system.

The invention will now be described by way of example, not by way of limitation,

Embodiments further explained.

1 shows a schematic representation of a, in particular first,

Measurement window series,

Fig. 2 shows a schematic representation of three measuring window rows, and

Fig. 3 shows a schematic diagram of an embodiment of the method according to the invention.

Unless otherwise indicated, the reference numerals correspond to the following

Process steps or components: Energy quantity calculation 1, validity check 2, control value determination Kontroll_NOx dws 3, control value comparison NOx dws 4, control value determination Kontroll_SCR Eff 5, control value comparison SCR Eff 6, combination logic 7, diagnosis quantity function 8 and diagnosis efficiency function 9, first measurement windows 10 second measuring windows 11, third measuring windows 12, further measuring windows 13, starting point of the first measuring window 14, end point of the first measuring window and starting point of the second measuring window 15, end point of the second measuring window and starting point of the third measuring window 16, end point of the third measuring window and starting point of the further measuring window 17, amount of energy in kilowatt hours 18, number of measuring windows n 19, amount of energy of a measuring window EEng 20, offset value Vw 21, first measuring windows of the first measuring window row 22, second measuring windows of the first measuring window row 23, third measuring windows of the first measuring window row 24, further measuring windows of the first measuring window 25, first measuring windows of the second measuring window row 26, second measuring windows of the second measuring window row 27, third measuring windows of the second measuring window row 28, further measuring windows of the second measuring window row 29, first measuring windows of the third

Measuring window row 30, second measuring windows of the third measuring window row 31, third measuring windows of the third measuring window row 32, further measuring windows of the third measuring window row 33, engine speed NEng 34, injected fuel quantity MfFulInj 35, limit value LimitNox dws 36, limit value LimitSCR 37, concentration of the exhaust gas component NOx in the mass flow or in the mass flow of the exhaust gas Conc_NOx_dwsSCR 38, mass flow or mass flow of the exhaust gas MfExh 39, concentration of the exhaust gas component NOx 40 in the mass flow or in the mass flow of the exhaust gas before entering the SCR system is Conc_NOx_usSCR 41, modeled concentration of the exhaust gas component NOx in the mass flow or in the mass flow of the exhaust gas after entering the SCR system is Conc_NOx_dwsSCR_model 42, control value ControlNOxdws 43, control value ControlSCR Eff 44, functional 45, non-functional 46, output and / or storage of status information 47.

Fig. 1 shows a schematic representation of a measurement window row, wherein the measurement windows 10, 11, 12, 13 are sequentially strung together. The measurement windows 10, 11, 12, 13 of this measurement window row start at a starting point 14, 15, 16, 17 and end at an end point 15, 16, 17 as soon as a predetermined amount of energy 20 has been converted by the internal combustion engine. That is, in this embodiment, the starting points 15, 16, 17 of the subsequent measurement windows essentially correspond to the end points 15, 16, 17 of the preceding measurement windows.

On the y-axis, the number of measurement window rows 19 and on the x-axis, the amount of energy in kilowatt hours 18 is plotted. In this embodiment, each measuring window corresponds to 10, 11, 12, 13 of a certain amount of energy 20 converted the internal combustion engine, in particular the engine of

Internal combustion engine. The measuring windows 10, 11, 12, 13 of the first

Measuring window row are defined essentially by the same amount of energy 20.

In this embodiment, the amount of energy 20 converted is the

Internal combustion engine continuously calculated or determined during the measurement window to determine the end point of the measurement window 15, 16, 17 can. The converted amount of energy 20 of the internal combustion engine is determined in this embodiment by including the engine speed, the engine power and the engine torque. During the first measuring window 10, in particular between the starting point 14 and the end point 15 of the measuring window, the total mass of at least one exhaust gas component is determined at one point in the course of the exhaust gas aftertreatment system. The measured values of at least one sensor and / or other data can be used to determine the total mass of an exhaust gas component. In this embodiment, for example, the measured values of NOx sensors and the exhaust gas volume flow are used to determine the total mass of the exhaust gas component NOx. Moreover, a control value is determined during the first measurement window 10, taking into account the specific mass of the at least one exhaust gas component.

Subsequently, during the first measurement window, the control value is compared with at least one limit value and then the validity of the first measurement window, the recorded measurement window, is assessed, taking into account at least one validity parameter.

After this step, status information about the function of the

Aftertreatment system output and / or stored 47.

After the predetermined amount of energy 20 has been converted by the internal combustion engine, the first measurement window 10 ends at its end point 15. In this embodiment, the second measurement window 11 starts at the end point of the first measurement window 15, the third measurement window 12 at the end point of the second measurement window 16 and each other Measuring window 13 at the end point of the previous measurement window 17. During each measurement window 10, 11, 12, 13, according to this embodiment, method steps, analogous to the method steps of the first measurement window 10, are repeated.

Fig. 2 shows a schematic representation of three rows of measuring windows. On the x-axis, the amount of energy in kilowatt hours is 18 and on the y-axis, the number of measurement window rows 19 is plotted.

The measurement windows of the respective measurement window row 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 are sequentially strung together. All measurement windows of all measurement window rows 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 are in this embodiment through the same

Energy amount 20 defined. According to an embodiment not shown, the measuring windows of different measuring window rows or the measuring windows of a measuring window row can be defined by different amounts of energy.

In this embodiment, the end points of the preceding measurement windows of the respective measurement window row essentially correspond to the starting points of the subsequent measurement windows of the respective measurement window row. During each measuring window 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, according to this embodiment, method steps are repeated analogously to the method steps of the first measuring window of FIG.

According to this embodiment, the measuring windows of the second measuring window row 26, 27, 28, 29 are opposite the measuring windows of the first measuring window row 22, 23, 24, 25 and the measuring windows of the third measuring window row 30, 31, 32, 33 opposite the measuring windows of the second measuring window row 26, 27, 28, 29 offset by an offset value 21. This means that, for example, the starting point of the first measuring window of the second measuring window row 26 is offset from the starting point of the first measuring window of the first measuring window row 22 by the offset value 21. Furthermore, for example, the starting point of the first measurement window of the third

Measurement window rows 30 offset from the starting point of the first measurement window of the second measurement window rows 26 by the same offset value 21.

According to this embodiment, the offset value 21 corresponds to a certain amount of energy, which is determined according to the following rule:

where Vw is the offset value 21, where EEng is the converted energy amount 20 of the internal combustion engine, in particular the amount of energy 20 of a measurement window, and where n is the number of measurement window rows 19.

The converted amount of energy 20 of the internal combustion engine, by means of the speed of the internal combustion engine and the injected fuel amount 35 or including the engine power, the engine speed 34 and the

Motor torque can be determined.

In particular, the offset value 21 corresponds to a fraction of the converted energy quantity 20 of the internal combustion engine, in particular a fraction of the amount of energy which determines the measurement window length. Preferably, the offset value corresponds to 1 / n of the converted amount of energy 20, where n is the number of measurement window rows 19. According to this embodiment, the offset value 21 thus corresponds to 1/3 of the converted amount of energy 20 of the internal combustion engine, which determines the measurement window length.

Fig. 3 shows a schematic representation of an embodiment of the method according to the invention. The graphically illustrated and described method steps are performed, for example, during a measurement window of the preceding figures.

According to this embodiment, the amount of energy 20 converted by the internal combustion engine is calculated by including the engine speed NEng 34 and the injected fuel amount MfFuInj 35. This so-called

Energy quantity calculation 1 is carried out during the measurements, ie preferably during the measurement window.

According to this embodiment, the functionality 45, 46 of the

Exhaust gas aftertreatment device checked by means of two diagnostic functions 8.9. The first diagnostic function, the so-called diagnostic quantity function 8, determines the control value KontrollNOx dws 43. This control value is calculated according to the following instructions:

where Mf_NOx_dwsSCR is the mass flow or mass flow of the exhaust gas component NOx after exiting the SCR system, where Conc_NO_dwsSCR is the concentration of the exhaust gas component NO in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, where Conc_NO2_dwsSCR is the concentration the exhaust gas component NO2 in the mass flow or in the mass flow of

Exhaust gas is after exit from the SCR system, where Mmol_NO is the molar mass of the exhaust gas component NO, where Mmol_NO2 is the molar mass of the exhaust gas component NO2, and where MfExh is the mass flow or the mass flow of the exhaust gas 39, where MmolExhGas the molar mass of the exhaust gas is.

The variable Conc_NOx_dwsSCR 38 indicated in the figure comprises the

Concentrations of the exhaust gas components NO2 and NO. According to this embodiment, the determination of the control value 43, ie in particular the above-mentioned integration, takes place during the entire measurement window, ie between the starting point and the end point of the respective measurement window.

After the control value determination KontrollNOxdws 3, the control value KontrollNOxdws 43 is compared with a predetermined limit value LimitNOxdws 36. In this case, according to this embodiment, it is checked whether the control value KontrollNOxdws 43 is above or below the limit value LimitNOx dws 36. If the control value KontrollNOx dws 43 corresponds to the limit value LimitNOx dws 36, this is evaluated in this embodiment as if the control value KontrollNOxdws 43 were above the limit value LimitNOx · dws 36.

Subsequently, in the so-called validity check 2, including the result of the control value comparison NOx dws 4 and the validity parameter, the functionality 45, 46 of the exhaust aftertreatment system is assessed according to the diagnostic quantity function 8. According to this embodiment, the engine speed NEng 34 and the injected fuel amount MfFuInj 35 are used as the validity parameters. In principle, however, many other parameters can also be used for the validity check. The recorded measurement window is only judged to be valid if the validity parameters are within a validity range for a certain duration during the measurement window.

The result of the functional evaluation 45, 46 of the

Exhaust gas aftertreatment system according to the diagnostic quantity function 8 is transferred to the combination logic 7.

According to this embodiment, the functionality 45, 46 of the

Exhaust after-treatment system also by means of a second diagnostic function, the so-called diagnostic efficiency function 9, checked. The second diagnostic function determines the control value KontrollSCREff 44, which is calculated according to the following rule:

wherein NOxEff sensor is the NOx conversion rate calculated from the measured values or the efficiency value of the SCR system determined during the measurement window, wherein M_win_NOx_dwsSCR determines the total mass of the exhaust gas component NOx after the exit from the SCR, determined from measured values during the measurement window. System, which may be determined according to the following rule:

wherein M_win_NOx_dwsSCR is the total mass of the exhaust gas component NOx after exiting the SCR system during the measurement window, where Mf_NOx_dwsSCR is the mass flow or mass flow of the exhaust gas component NOx after exiting the SCR system, where Conc_NO_dwsSCR is the concentration of the exhaust gas component NO in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, where Conc_NO2_dwsSCR is the concentration of the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, where Mmol_NO is the molar mass of the exhaust gas component NO, where Mmol_NO2 is the molar mass of the exhaust gas component NO2, where MfExh is the mass flow or mass flow of the exhaust gas 39, where MmolExhGas is the molar mass of the exhaust gas,

wherein M_win_NOx_usSCR is the total mass of the exhaust gas component NOx before the entry into the SCR system, determined from measured values during the measurement window, which is optionally determined according to the following procedure:

wherein M_win_NOx_usSCR is the total mass of the exhaust gas component NOx before entering the SCR system during the measurement window, where Mf_NOx_usSCR is the mass flow or mass flow of the exhaust gas component NOx before entering the SCR system, where Conc_NO is the concentration of the exhaust gas component NO in the mass flow or mass flow of the exhaust gas before entering the SCR system, wherein Conc_NO2 is the concentration of the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas before entering the SCR system, wherein Mmol_NO the molar mass of the exhaust gas component NO, where Mmol_NO2 is the molar mass of the exhaust gas component NO2, where MfExh is the mass flow or mass flow of the exhaust gas 39, where MmolExhGas is the molar mass of the exhaust gas, NOxEff model representing the modeled NOx conversion rate and the modeled efficiency value of the SCR, respectively System during the measurement window, and where M_win_NOx_dwsSCR_model modeled during the measurement window , total mass of the exhaust gas component NOx after exiting the SCR system 42 is.

The variables Conc_NOx_usSCR 41 and Conc_NOx_dwsSCR 38 given in the figure comprise the concentrations of the exhaust gas components NO2 and NO. According to this embodiment, the determination of the control value, that is to say in particular the integration specified above, takes place during the entire measuring window, ie between the starting point and the end point of the respective measuring window.

After the control value determination KontrollSCREff 5, the control value KontrollSCREff 44 is compared with a predetermined limit LimitSCREff 37. In this case, it is checked according to this embodiment, whether the control control value ControlSCR Eff 44 on

or below the limit LimitSCREff 37. If the control value CONTROLSCREff 44 corresponds to the limit value LimitSCR Eff 37, this is rated in this embodiment as if the control value ControlSCR Eff 44 were below the limit value LimitSCR Eff 37.

Subsequently, in the so-called validity check 2, including the result of the control value comparison SCR Eff 6 and the validity parameter, the functionality 45, 46 of the exhaust aftertreatment system is assessed according to the diagnostic efficiency function 9. According to this embodiment, the engine speed NEng 34 and the injected fuel amount MfFuInj 35 are used as the validity parameters. The recorded measurement window is only judged to be valid if the validity parameters are within a validity range for a certain duration during the measurement window.

The judgment about the functionality 45, 46 of the exhaust aftertreatment system according to the so-called diagnostic efficiency function 9 is transferred to the combination logic 7.

In the combination logic 7, it is determined whether information, in particular status information, is output and / or stored for the function of the exhaust aftertreatment system 47. According to this embodiment, the status information is output and stored 47 only if one of the two diagnostic functions 8, 9 is the exhaust aftertreatment system assessed as non-functional 46. This is the case if the control value ControlNOx dws 43 is above the limit LimitNOx dws 36 for a predetermined number of consecutive measurement windows and the measurement window is defined as valid or if the ControlSCREff 44 control value for a pre-determined number of consecutive measurement windows is LimitSCR Eff 37 and the measurement window is defined as valid.

It is provided that the output of the status information 47 takes place by means of switching on the MIL lamp. This makes it possible, for example, the driver of the motor vehicle on the lack of functionality 45, 46 of his

Aftertreatment system to inform.

Claims (17)

claims A method for functional testing of an exhaust aftertreatment system of an internal combustion engine, in particular an exhaust aftertreatment component, such as an SDPF or an SCR catalyst, comprising the following steps: determining a measurement window by calculating the amount of energy converted by the internal combustion engine, wherein the measurement window starts at a starting point and a ends at a final point, determines the mass of at least one exhaust gas component occurring overall during the measurement window at one point in the course of the exhaust aftertreatment system, determines at least one information about the function of the exhaust aftertreatment system giving the control value including the determined mass of the at least one exhaust gas component, - comparing the at least one control value with at least one limit value, - assessing the validity of the recorded measurement window taking into account at least one valid repeating the steps for further measuring windows which are lined up sequentially and thereby form a first measuring window row, the starting point of the further measuring window of the first measuring window row in particular the end point of the preceding measuring window corresponds to the first measurement window row. 2. The method according to claim 1, characterized in that a second measurement window row is formed, the measurement window offset by a certain offset value, in particular by a certain amount of energy relative to the first measurement window row. 3. The method according to claim 1 or 2, characterized in that at least one further measuring window row is formed, the measuring window by a certain offset value, in particular by a certain amount of energy, compared to another range of measurement windows, are offset. 4. The method according to any one of the preceding claims, characterized in that all the measurement windows of a measurement window row or all measurement windows of all measurement window rows are defined by the same amount of energy. 5. The method according to any one of claims 2 to 4, characterized in that - the starting points of the measurement windows of a measurement window row are offset from the starting points of the measurement windows of another measurement window row by the, in particular same, offset value, - and / or that the starting points of the measurement windows all Measurement window rows are offset from the starting points of the measurement window of all other measurement window rows by the respective offset values. 6. The method according to any one of claims 2 to 5, characterized in that the determination of the offset value and / or the offset values Vw is carried out according to the following rule: - where Vw is the offset value, - where EEng is the converted amount of energy of the internal combustion engine, in particular the amount of energy of a measurement window, - and where n is the number of measurement window rows. 7. The method according to any one of claims 2 to 6, characterized in that - the offset value 1 / n of the converted amount of energy of the internal combustion engine, in particular the amount of energy converted a measurement window, where n is the number of measurement window rows, - or that the offset value in particular 1 / 2 of the converted amount of energy of the internal combustion engine, in particular the amount of energy converted a measurement window corresponds to 2 Meßfensterreihen, - or that the offset value in particular 1/3 of the converted amount of energy of the internal combustion engine, in particular the amount of energy converted a measurement window corresponds to 3 Meßfensterreihen, - or that the offset value in particular 1/4 of the amount of energy converted the internal combustion engine, in particular the amount of energy converted a measurement window, in 4 measurement window rows corresponds, - or that the offset value in particular 1/5 of the converted amount of energy of the internal combustion engine, in particular the amount of energy converted a measurement window, at 5 measuring window rows corresponds, - or that the offset value, in particular the amount of energy converted a measurement window, in particular 1/6 of the converted amount of energy of the internal combustion engine, in particular the amount of energy converted a measurement window corresponds to 6 Meßfensterreihen, - or that the offset value in particular 1/7 of the converted Energy amount of the internal combustion engine, in particular the amount of energy converted a measurement window, at 7 measurement window rows corresponds, - or that the offset value in particular 1/8 of the converted amount of energy of the internal combustion engine, in particular the umg set energy quantity of a measuring window, corresponding to 8 rows of measuring windows, or that the offset value corresponds in particular to 1/9 of the converted amount of energy of the internal combustion engine, in particular the amount of energy of a measuring window, with 9 rows of measuring windows, or that the offset value is in particular 1/10 of the amount of energy converted Combustion engine, in particular the amount of energy converted a measurement window, corresponds to 10 rows of measurement windows. 8. The method according to any one of the preceding claims, characterized in that - the amount of energy converted by the internal combustion engine by means of the rotational speed of the internal combustion engine, in particular the engine speed, NEng and the injected fuel quantity MfFulInj is calculated, - and / or that the calculation of the internal combustion engine converted amount of energy according to the following rule: where EEng is the amount of energy converted by the internal combustion engine during a measurement window, - where PwrEng is the engine power, - where NEng is the engine speed, - and where TqEng is the engine torque. 9. Method according to one of the preceding claims, characterized in that measured values of at least one sensor, in particular measured values of at least one NOx sensor and the exhaust gas volume flow, are used for determining the total mass of an exhaust gas component during the measuring window, and in that at least one sensor in the course of the exhaust aftertreatment system, in particular in front of the SCR system and / or after the SCR system, is arranged. 10. The method according to any one of the preceding claims, characterized in that the determination of the total mass of an exhaust gas component during the measurement window at a point in the course of the exhaust aftertreatment plant according to the following rule: - where M_win_i the total mass of the exhaust gas component i. where Mf_i is the mass flow or the mass flow of the exhaust gas component i. where Conc_i is the concentration of the exhaust gas component i. in the mass flow or in the mass flow of the exhaust gas, - where MfExh is the mass flow or the mass flow of the exhaust gas, - where Mmol_i is the molar mass of the exhaust gas component i. is - and where MmolExhGas is the molar mass of the exhaust gas. 11. The method according to any one of the preceding claims, characterized in that the determination of a control value KontrollSCR Eff, which allows an explanation of the function of the exhaust aftertreatment system, according to the following rule: wherein NOxEff sensor is the NOx conversion rate calculated from the measured values or the efficiency value of the SCR system during the measuring window, where M_win_NOx_dwsSCR is the total mass of the exhaust gas component NOx after exiting the SCR determined from measured values during the measuring window System, which may be determined according to the following rule: wherein M_win_NOx_dwsSCR is the total mass of the exhaust gas component NOx after exiting the SCR system during the measurement window, - where Mf_NOx_dwsSCR is the mass flow or mass flow of the exhaust gas component NOx after exiting the SCR system, where Conc_NO_dwsSCR is the concentration the exhaust gas component NO is in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, - where Conc_NO2_dwsSCR is the concentration of the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas after exiting the SCR system, - where Mmol_NO the molar mass of the exhaust gas component NO is, - where Mmol_NO2 is the molar mass of the exhaust gas component NO2, - where MfExh is the mass flow or the mass flow of the exhaust gas, - where MmolExhGas is the molar mass of the exhaust gas, - where M_win_NOx_usSCR is the total mass of the exhaust gas component NOx before entry into the SCR system determined from measured values during the measurement window, which is determined according to the following procedure: - where M_win_NOx_usSCR is the total mass of the exhaust gas component NOx before entering the SCR system during the measurement window, - where Mf_NOx_usSCR is the mass flow or mass flow of the exhaust gas component NOx before entering the SCR system, - Conc_NO is the concentration the exhaust gas component is NO in the mass flow or mass flow of the exhaust gas before entering the SCR system, - where Conc_NO2 is the concentration of the exhaust gas component NO2 in the mass flow or in the mass flow of the exhaust gas before entering the SCR system, - where Mmol_NO the molar mass of the exhaust gas component NO is, - where Mmol_NO2 is the molar mass of the exhaust gas component NO2, - where MfExh is the mass flow or mass flow of the exhaust gas, - where MmolExhGas is the molar mass of the exhaust gas, - NOxEff model is the modeled NOx Conversion rate or the modeled efficiency value of the SCR system during the measurement window, where M_win_NOx_dwsSCR_model is the one during the measurement window s modeled, total mass of the exhaust gas component NOx after exiting the SCR system, and - where ControlSCREff is the control value based on the determined efficiency values. 12. The method according to any one of the preceding claims, characterized in that the determination of a control value KontrollNOxdws, which allows an explanation of the function of the exhaust aftertreatment system, according to the following rule: wherein Mf_NOx_dwsSCR is the mass flow or the mass flow of the exhaust gas component NOx after exiting the SCR system, wherein Conc_NO_dwsSCR is the concentration of the exhaust gas component NO in the mass flow or in the exhaust gas mass flow after exiting the SCR system Conc_NO2_dwsSCR is the concentration of the exhaust gas component NO2 in the mass flow or mass flow of the exhaust gas after exiting the SCR system, - where Mmol_NO is the molar mass of the exhaust gas component NO, - where Mmol_NO2 is the molar mass of the exhaust gas component NO2, - where MfExh is the Mass flow or mass flow of the exhaust gas is, - where MmolExhGas is the molar mass of the exhaust gas, - and wherein KontrollNOxdws is the control value, which is based on the determined from measured values total mass of the exhaust gas component NOx after exiting the SCR system. 13. The method according to any one of the preceding claims, characterized in that - a limit value LimitSCR Eff is used to compare the control value KontrollSCREff, wherein the limit value LimitSCR Eff a predetermined efficiency value of the exhaust aftertreatment system and / or a predetermined efficiency value of an exhaust aftertreatment component, in particular an SCR -Systems, is and / or that a limit value LimitNoxdws is used to compare the control value KontrollNOx dws, wherein the limit value LimitNOx dws is a predetermined, total mass of an exhaust gas component, in particular the total mass of NOx after the last exhaust gas component, in particular the SCR system, the exhaust aftertreatment system is. 14. Method according to one of the preceding claims, characterized in that - the measurement window is defined as valid if the at least one validity parameter lies within a validity range for a certain duration during the measurement window, and / or if the measurement window is defined as invalid, if the at least one validity parameter is outside a validity range for a certain duration during the measurement window - and / or the measurement window is defined as invalid if a predetermined number of validity area overflows, underflow scores, and / or validity area violations are exceeded. 15. The method according to any one of claims 13 or 14, characterized in - that the function of the exhaust aftertreatment system is defined as functional if the control value KontrollSCR Eff is above the limit LimitSCR Eff and the measurement window is defined as valid, - and / or Function of the exhaust aftertreatment system is defined as functional if the control value KontrollNOx dws is below the limit value LimitNOx dws and the measurement window is defined as valid. 16. The method according to any one of claims 13 to 15, characterized in that the functionality of the exhaust aftertreatment system is output and / or stored when the control value KontrollSCR Eff is above or below the limit LimitSCR Eff and the measurement window is defined as valid, and / or if the control value ControlNOx dws is above or below the LimitNOx dws limit and the measurement window is defined as valid. 17. The method according to any one of the preceding claims, characterized in that the status information on the function of the exhaust aftertreatment system by means of a MIL lamp "Malfunction Indicator Light - engine indicator light" of a vehicle is issued, whereby the driver is informed about the status of the functionality of the exhaust aftertreatment system.