DE102024203213A1 - Method, control device and computer program product for on-board determination of pollutant emission masses of an internal combustion engine with an exhaust aftertreatment device - Google Patents

Abstract

The method according to the invention for the on-board determination of pollutant emission masses of an internal combustion engine (1) with an exhaust gas aftertreatment device (2) is carried out by means of an electronic control device (7) assigned to the internal combustion engine (1) and/or the exhaust gas aftertreatment device (2) by executing program instructions of the computer program product (20) according to the invention. Sensor signal values (AS_Sig) provided by an exhaust gas sensor (6c) are detected, and pollutant emission values are continuously determined based thereon. The pollutant emission masses during operation of the internal combustion engine (1) are calculated based on the pollutant emission values. At the same time, the determined pollutant emission values are stored in an electronic storage device (7b) of the electronic control device (7) according to the invention, grouped into emission value groups depending on operating parameter ranges of the internal combustion engine (1) and/or the exhaust gas aftertreatment device (2). On this basis, pollutant emission substitute values associated with the respective operating parameter ranges are determined. The pollutant emission substitute values are used as a substitute to determine the pollutant emission masses during operation if temporarily no or only implausible sensor signal values (AS_Sig) are available and thus no usable, current pollutant emission values are available.

Description

The invention relates to a method for the on-board determination of pollutant emission masses of an internal combustion engine with an exhaust gas aftertreatment device, i.e., the pollutant emission masses that leave the exhaust gas aftertreatment device downstream of the internal combustion engine and are thus released into the environment. On-board determination in this case means that the pollutant emission masses are continuously determined during the intended operation of the internal combustion engine using an electronic measuring device assigned to the internal combustion engine and/or the exhaust gas aftertreatment device. This corresponds to so-called on-board monitoring (OBM) of pollutant emissions during operation. Such an electronic measuring device generally consists of an electronic control device provided for operating the internal combustion engine and/or the exhaust gas aftertreatment device, and at least one exhaust gas sensor connected to the control device for signaling purposes, which provides sensor signal values representative of a concentration of at least one pollutant in the exhaust gas stream of the internal combustion engine leaving the exhaust gas aftertreatment device. The electronic control device receives the sensor signal values and calculates the pollutant emission masses on this basis by executing corresponding stored program instructions in an electronic processing unit (processor).

The invention further relates to an electronic control device and a computer program product with program instructions for carrying out the method.

Current and future legislation stipulates that the emissions behavior of motor vehicles (motor vehicles), particularly the internal combustion engines that power them and their exhaust aftertreatment systems, must be continuously monitored during operation, and any deterioration must be detected. The legislation provides for the use of so-called on-board monitoring systems (OBM systems), which continuously record the emission of pollutants into the environment at the outlet of the exhaust aftertreatment system. Furthermore, the legislation requires the reliable detection of non-compliance with emission limits during real-world operation. This may also require ensuring and monitoring the proper functioning of the respective on-board monitoring system.

Compliance with the legal requirements is checked by the legislator as part of the certification of a newly registered vehicle as well as over the life cycle defined by the operating period or the operating kilometers, as part of a so-called in-service conformity test (ISC test), which in the future will include the review of the respective OBM system.

Due to different measurement accuracies of the reference measurement technology used for the verification and the large-scale technology used in the OBM system for continuous measurement in the real, intended operation of a series-produced internal combustion engine or the corresponding vehicle, there is inevitably a deviation between the measurement result of the reference measurement and the measurement result of the OBM system.

Such a deviation may also arise in particular because, under certain boundary conditions, no or no reliable measurements can be carried out using the OBM system during operation.

• - Die ggf. verzögerte technische Betriebsbereitschaft eines Abgas-Sensors beim Starten der Brennkraftmaschine;
• - ggf. auftretende kurzzeitige Störungen bei der Übertragung einzelner Abgas-Sensorwerte zum Steuergerät, in dem die Funktionalität des OBM-Systems realisiert ist;
• - funktionsbedingte, kurzzeitige Störungen der Abgas-Sensoren, die zu unplausiblen, ungültigen Sensorwerten führen.

These can be, for example, the following boundary conditions:

• - The possible delay in the technical operational readiness of an exhaust gas sensor when starting the internal combustion engine;
• - possible short-term disturbances in the transmission of individual exhaust gas sensor values to the control unit in which the functionality of the OBM system is implemented;
• - functional, short-term malfunctions of the exhaust gas sensors, which lead to implausible, invalid sensor values.

In particular, if such malfunctions are not detected or do not lead to an error entry in the OBM system, the pollutant masses emitted during these operating phases are not recorded or are only recorded insufficiently and thus reduce the pollutant masses recorded by the OMB system.

Since the reference measurement system operates continuously and without interruptions, this results in an increased deviation from the reference measurement results. If the deviation of the measurement results lies outside a defined tolerance range, the OBM system is considered "non-compliant with the law." This applies in particular if the reference measurement result indicates an exceedance of the limit values that was not detected by the OBM system.

The present invention is therefore based on the object of increasing the accuracy of the determination of the emitted pollutant masses by means of an on-board monitoring system and of to enable improved diagnosis of the functionality of the OBM system in order to exclude non-conformities in the ISC test as far as possible.

This object is achieved by a method, an electronic control device and a computer program product having the features according to the independent claims.

Advantageous embodiments, developments, and details of the present invention emerge from the dependent claims, the description, and the drawings. The advantageous embodiments and developments can be used individually or, provided they are not mutually exclusive alternatives, in combination with one another. Features and details described in connection with the method naturally also apply in connection with the electronic control device and the computer program product, and vice versa, so that with regard to the disclosure of this invention, reference can always be made to the individual aspects of the invention.

The advantages of the invention are essentially that a more precise, more realistic determination of the mass of pollutants emitted by an internal combustion engine during normal operation and over its service life can be carried out by means of an on-board monitoring system.

According to the invention, a method is provided for the on-board determination of pollutant emission masses of an internal combustion engine with an exhaust gas aftertreatment device. This corresponds to so-called on-board monitoring of pollutant emissions. The method is carried out by means of an electronic control device assigned to the internal combustion engine and/or the exhaust gas aftertreatment device. The electronic control device can be a central control device or a part or subsystem of a central control device of the internal combustion engine or also a part or subsystem of an on-board monitoring system of a motor vehicle, as well as a separate electronic control device for implementing the method.

Within the scope of the method, sensor signal values provided by at least one exhaust gas sensor, which are representative of a concentration of at least one pollutant in the exhaust gas flow of the internal combustion engine, are recorded and, on the basis of these sensor signal values, corresponding pollutant emission values are continuously determined.

Within the scope of the invention, sensor signal values can also be provided by multiple exhaust gas sensors, each representative of the concentration of a specific pollutant in the exhaust gas stream. Likewise, one exhaust gas sensor can provide a signal representative of the total concentration of several different pollutants in the exhaust gas stream. Pollutants whose concentrations in the exhaust gas stream can be determined in this way include nitrogen oxides (NOx), hydrocarbons (HC), and ammonia ( _NH3 ).

The pollutant emission values are, for example, values for the concentration of the respective pollutant in the exhaust gas stream.

The pollutant emission masses are then calculated during continuous operation of the internal combustion engine based on the pollutant emission values. For this purpose, values of the current exhaust flow can be used if necessary, and a respective mass flow of the pollutant in question, i.e., the pollutant emission mass, can be calculated.

The method is particularly characterized by the fact that the determined pollutant emission values, virtually parallel to the calculation of the current pollutant emission masses, are stored in a memory area or an electronic storage device of the electronic control device, grouped into emission value groups depending on the operating parameter ranges of the internal combustion engine and/or the exhaust gas aftertreatment device. Based on these emission value groups, substitute pollutant emission values corresponding to the respective operating parameter ranges are then determined.

These pollutant emission substitute values are then used to determine the pollutant emission masses during operation, depending on the operating parameter ranges of the internal combustion engine and/or the exhaust gas aftertreatment device, instead of the currently determined pollutant emission values, if temporarily no or only implausible sensor signal values and thus no usable, current pollutant emission values are available.

In this way, even in operating phases where no or no reliable sensor signal values are available, pollutant emission substitute masses are calculated that are very close to the actual pollutant emission masses. This results in no or only very small shortfalls and deviations from the values that can be determined with an external reference measuring system. The determination of pollutant emission masses and conformity with legal requirements remains guaranteed.

Further advantageous embodiments and refinements of the method according to the invention are disclosed in the subclaims, as described below.

In one embodiment of the method, at least one of the following measures is initiated if the pollutant emission masses exceed a predetermined threshold. This can be done either selectively or in combination by issuing a warning or error message to an operator of the internal combustion engine, storing a warning or error message in an error memory of the electronic control device, restricting the operation of the internal combustion engine to operating ranges with low pollutant emissions, and/or initiating the shutdown of the internal combustion engine. This advantageously ensures that the internal combustion engine does not exceed the legally prescribed emission limits or only does so for a limited period of time.

In a further embodiment of the method, the pollutant emission values determined on the basis of the sensor signal values for a respective operating parameter range are compared or related to the pollutant emission substitute values for the respective operating parameter range. In this way, an emissions comparison value is determined. If the determined emissions comparison value exceeds a specified upper threshold or falls below a specified lower threshold, the on-board determination of the pollutant emission masses, and thus the on-board monitoring system, is identified as faulty and displayed to the operator as an error message or stored as an error in an error memory for later diagnosis. Advantageously, measures can then be taken in response to this to correct the deviations and, if necessary, to prevent increased pollutant emissions.

In one version of the procedure, the pollutant emission substitute values assigned to the operating parameter ranges are determined by calculating an average over the stored pollutant emission values of the respective emission value group, or by filtering, weighting and bundling the stored pollutant emission values of the respective emission value group, or by a statistical evaluation of the stored pollutant emission values of the respective emission value group. The aforementioned methods can, however, also be used in combination. By applying one or more of these methods in combination, a pollutant emission substitute value is determined that is very likely to be very close to the current pollutant emission value of the current operating parameter range. The pollutant emission substitute masses determined on this basis therefore also correspond to the actual current pollutant emission masses with a high degree of probability and good accuracy.

In a further development of the method, a total pollutant emission mass for the past operating period is determined by integrating the pollutant emission masses continuously determined over the past operating period of the internal combustion engine. This allows for the analysis of the emitted pollutant mass across different operating parameter ranges.

Based on the previously described determination of a total pollutant emission mass, an emissions ratio value can be calculated from the total pollutant emission mass and the associated past operating time or a distance traveled during the operating time of a motor vehicle powered by an internal combustion engine, or the energy converted over the operating time of the internal combustion engine. This enables the determination and monitoring of emissions during practical driving of a motor vehicle powered by a corresponding internal combustion engine, which is also known as "Real Driving Emissions" (RDE). The determined pollutant emission masses are integrated over the operating time related to a specific distance traveled and compared to the distance traveled. In this way, compliance with the legally prescribed limit values can be advantageously monitored and, if necessary, corrective measures can be taken to ensure passing an in-service conformity test (ISC test).

• - Ausgabe einer Warn- oder Fehlermeldung an einen Betreiber der Brennkraftmaschine und Abspeicherung dieser Fehlermeldung in einem Fehlerspeicher der elektronischen Steuerungsvorrichtung;
• - Beschränkung des Betriebs der Brennkraftmaschine auf Betriebsbereiche mit niedrigen Schadstoff-Emissionen oder
• - Stilllegung der Brennkraftmaschine.

In continuation of the above-mentioned form of the procedure, if the respective emission ratio value, for example a pollutant mass per kilometer, exceeds a specified threshold, for example 80 mg/Km NOx, according to the Euro 6 emissions regulation, at least one of the following measures can be initiated:

• - issuing a warning or error message to an operator of the internal combustion engine and storing this error message in an error memory of the electronic control device;
• - Restriction of the operation of the internal combustion engine to operating ranges with low pollutant emissions or
• - Decommissioning of the internal combustion engine.

The measures mentioned can be implemented individually or in combination, provided they are not mutually exclusive. This can advantageously prevent increased pollutant emissions that may exceed legal requirements.

• - aktuelle Drehzahl der Brennkraftmaschine,
• - aktuell abgegebene Leistung/Last der Brennkraftmaschine,
• - aktueller Ansaugluftmassenstrom,
• - aktueller Ladedruck im Ansaugtrakt,
• - aktuelle zugeführte Kraftstoffmasse,
• - aktueller Abgasrückführungsstrom,
• - aktuelle Betriebstemperatur der Brennkraftmaschine,
• - aktuelle Betriebstemperatur der Abgasnachbehandlungsvorrichtung,
• - Abgastemperatur vor der Abgasnachbehandlungsvorrichtung,
• - Abgastemperatur nach der Abgasnachbehandlungsvorrichtung,
• - Größe des Abgasstromes,
• - Umgebungstemperatur.

In a further embodiment of the method according to the invention according to one of the aforementioned embodiments, the operating parameter ranges are delimited by values or value ranges of at least one or more of the following operating parameters:

• - current speed of the internal combustion engine,
• - current output power/load of the internal combustion engine,
• - current intake air mass flow,
• - current boost pressure in the intake tract,
• - current fuel mass supplied,
• - current exhaust gas recirculation flow,
• - current operating temperature of the internal combustion engine,
• - current operating temperature of the exhaust aftertreatment device,
• - exhaust gas temperature before the exhaust aftertreatment device,
• - exhaust gas temperature after the exhaust gas aftertreatment device,
• - size of the exhaust gas flow,
• - Ambient temperature.

This does not preclude additional delimitation using other, unmentioned parameters. Preferably, operating parameters are used in combination, each of which characterizes a specific pollutant emission behavior of the internal combustion engine. Whenever the internal combustion engine is operated with an operating parameter combination within these respective limits, the associated pollutant emission values determined based on the sensor signal values are stored in the associated emission value group. Using the aforementioned operating parameters, it is advantageous to define sensibly defined operating parameter ranges or emission value groups. Adjacent operating parameter ranges can also overlap.

According to a continuation of the above embodiment, the values or value ranges of the respective operating parameter(s) that define a respective operating parameter range can be changed over the operating life of the internal combustion engine. The operating life can characterize specific operating phases, but can also encompass the entire service life of the internal combustion engine. This allows the operating parameter ranges to be adapted to frequently occurring operating patterns (e.g., sporty or economical driving when used in a motor vehicle, etc.). Age-related operating changes, such as wear, can also be taken into account in this way.

In a further embodiment of the method, a pollutant emission value determined based on the sensor signal values can be stored in parallel in several, particularly two adjacent, emission value groups. This can be the case, for example, if adjacent operating parameter ranges overlap. This allows for a more detailed coverage of the internal combustion engine's operation by the defined operating parameter ranges and a more precise assignment of pollutant emission substitute values.

In another embodiment of the method, pollutant emission values from several, particularly two or three adjacent, emission value groups are combined to determine a pollutant emission substitute value for an operating parameter range. This enables the pollutant emission substitute values to be equalized, particularly in operating parameter ranges where discontinuous, erratic emission behavior of the internal combustion engine is to be expected.

The method according to the invention, in all of its aforementioned embodiments, can be applied both to individual pollutants, such as NOx, CH, or NH3 in the exhaust stream, and to the total pollutant values of several pollutants combined in the exhaust gas. This depends largely on the available exhaust gas sensors.

An electronic control device according to the invention for operating an internal combustion engine with an exhaust gas aftertreatment device has at least one electronic memory device in which at least one computer program product with program instructions is provided, and an input/output interface which is designed to receive and output electrical signals, as well as an electronic processing unit (processor) with access to the at least one electronic memory storage device and the input/output interface for executing the program instructions. When the program instructions are executed by the electronic processing unit, they cause the electronic control device to carry out the method according to one of the preceding claims. The electronic control device is therefore configured to carry out a method according to one of the previously described embodiments. The advantages of this electronic control device, like the method, are essentially that a more precise, more realistic determination of the mass of pollutants emitted by an internal combustion engine during intended operation and over its service life can be carried out by means of an on-board monitoring system.

A computer program product according to the invention for operating an internal combustion engine with an exhaust gas aftertreatment device comprises program instructions for execution by the electronic computing unit of the aforementioned electronic control device, wherein the program instructions, when executed by the electronic computing unit, cause the electronic control device to carry out the method according to one of the previously described embodiments.

Here, too, the main advantages are that a more precise, more realistic determination of the mass of pollutants emitted by an internal combustion engine during normal operation and over its service life can be carried out using an on-board monitoring system.

The features and combinations of features of the embodiments of the subject matter according to the invention mentioned above in the description or below in the description of the figures are, insofar as they are not applicable alternatively or even mutually exclusive, to be used individually, in part or in whole, also in mutual combination or mutual supplementation, in further development of the subject matter according to the invention, without departing from the scope of the invention.

Particularly advantageous embodiments, details or developments of the invention are explained in more detail below with reference to the figures, although the subject matter of the invention is not limited to these examples.

• 1 eine vereinfachtes Ablaufdiagramm zur Darstellung des Verfahrens
• 2 eine vereinfachte schematische Darstellung einer Brennkraftmaschine mit Abgasnachbehandlungsvorrichtung.

They show:

• 1 a simplified flow chart to illustrate the procedure
• 2 a simplified schematic representation of an internal combustion engine with exhaust aftertreatment device.

The figures in the drawings of this application are to be viewed merely as schematic, and the proportions of the individual figures and the elements depicted in the figures are not to be considered to scale. Rather, individual elements may be exaggerated for clarity and/or clarity. Elements with the same function, designation, type, or effect are identified by the same reference numerals throughout the figures. Individual reference numerals may be omitted in individual figures to improve clarity.

In 1 An example of the sequence of an embodiment of the method according to the invention is shown in a highly simplified manner in individual method steps. The method is carried out by means of an electronic control device 7 assigned to the internal combustion engine 1 and/or the exhaust gas aftertreatment device 2. However, the method according to the invention and its described embodiments are not to be limited to the 1 The procedural steps and relationships shown are to be interpreted in a limited manner.

The method for on-board determination of pollutant emission masses of an internal combustion engine 1 with an exhaust gas aftertreatment device 2 begins in this illustration with the control device detecting, as symbolized by method step VS_1, sensor signal values AS_Sig provided by at least one exhaust gas sensor 6c, which are representative of a concentration of at least one pollutant in the exhaust gas of the internal combustion engine. The exhaust gas sensor 6c is advantageously arranged at the outlet of the exhaust gas aftertreatment device 2, where it detects the pollutant concentration of the exhaust gas escaping into the environment.

Based on these sensor signal values AS_Sig, pollutant emission values are continuously determined, which is represented by process step VS_2. The pollutant emission values provide information, for example, about the pollutant concentration in the exhaust stream.

The pollutant emission values determined in VS_2 are stored in parallel in a memory area or in an electronic storage device 7b of the electronic control device 7 as a function of operating parameter ranges of the internal combustion engine 1 and/or the exhaust gas aftertreatment device 2 in emission value groups stored in summary form, as shown by process step VS_2A.

The operating parameter ranges are delimited by values or value ranges of operating parameters BePa of the internal combustion engine 1 and/or the exhaust gas aftertreatment device 2. The required operating parameters BePa associated with the respective sensor signal value AS_Sig are recorded in the process step marked with BePa and made available for assignment of the sensor signal values AS_Sig.

• - aktuelle Drehzahl der Brennkraftmaschine,
• - aktuell abgegebene Leistung/Last der Brennkraftmaschine,
• - aktueller Ansaugluftmassenstrom,
• - aktueller Ladedruck im Ansaugtrakt,
• - aktuelle zugeführte Kraftstoffmasse,
• - aktueller Abgasrückführungsmassenstrom,
• - aktuelle Betriebstemperatur der Brennkraftmaschine,
• - aktuelle Betriebstemperatur der Abgasnachbehandlungsvorrichtung,
• - Abgastemperatur vor der Abgasnachbehandlungsvorrichtung,
• - Abgastemperatur nach der Abgasnachbehandlungsvorrichtung,
• - Größe des Abgasmassenstromes,
• - Umgebungstemperatur.

For this purpose, the following operating parameters BePa can be used individually or in a sensible combination of two, three or more:

• - current speed of the internal combustion engine,
• - current output power/load of the internal combustion engine,
• - current intake air mass flow,
• - current boost pressure in the intake tract,
• - current fuel mass supplied,
• - current exhaust gas recirculation mass flow,
• - current operating temperature of the internal combustion engine,
• - current operating temperature of the exhaust aftertreatment device,
• - exhaust gas temperature before the exhaust aftertreatment device,
• - exhaust gas temperature after the exhaust gas aftertreatment device,
• - size of the exhaust gas mass flow,
• - Ambient temperature.

This list of operating parameters BePa is not to be considered exhaustive and other operating parameters not mentioned above may also be used within the framework of the procedure.

On the basis of these stored emission value groups, pollutant emission substitute values corresponding to the respective operating parameter ranges are determined, as shown by process step VS_2B.

The pollutant emission substitute values assigned to the operating parameter ranges can be determined, for example, by calculating an average of the stored pollutant emission values of the assigned emission value groups. Optionally or additionally, filtering, weighting, bundling, and/or a statistical evaluation of the stored pollutant emission values can also be performed.

In process step VS_3, the pollutant emission masses during operation of the internal combustion engine are calculated based on the previously determined pollutant emission values or the pollutant emission substitute values determined in VS_2B. Whether the pollutant emission values or the pollutant emission substitute values are used directly to calculate the pollutant emission masses is decided in the decision step symbolized by ES_1. For example, the exhaust gas mass flow is used to calculate the pollutant emission masses. In conjunction with the pollutant emission values or the pollutant emission substitute values, the pollutant emission mass is determined as a pollutant mass flow.

The pollutant emission substitute values are used as a substitute for determining the pollutant emission masses during operation, depending on the operating parameter ranges of the internal combustion engine and/or the exhaust aftertreatment device (2), if temporarily no or only implausible sensor signal values AS_Sig and thus no usable, current pollutant emission values are available, which is represented by the decision path marked "no." However, if plausible, i.e., valid, sensor signal values AS_Sig and thus valid pollutant emission values are available, these are used directly to calculate the pollutant emission masses, which is represented by the decision path marked "yes."

• - Ausgabe einer Warn- oder Fehlermeldung an einen Betreiber der Brennkraftmaschine
• - Abspeicherung einer Warn- oder Fehlermeldung in einem Fehlerspeicher der elektronischen Steuerungsvorrichtung,
• - Beschränkung des Betriebs der Brennkraftmaschine auf Betriebsbereiche mit niedrigen Schadstoff-Emissionen,
• - Stilllegung der Brennkraftmaschine.

If it is determined in the following decision step ES_2 that the previously determined pollutant emission masses exceed a specified threshold value, which is indicated by the decision path “yes”, at least one of the following measures is initiated in process step VS_4:

• - Output of a warning or error message to an operator of the internal combustion engine
• - Storage of a warning or error message in an error memory of the electronic control device,
• - Restriction of the operation of the internal combustion engine to operating ranges with low pollutant emissions,
• - Decommissioning of the internal combustion engine.

In process step VS_5, the AS-Sig values based on the sensor signal values for a The pollutant emission values determined in VS_2 for the relevant operating parameter range are compared or related to the pollutant emission substitute values determined in VS_2B for the relevant operating parameter range, thus determining an emission comparison value. If it is then detected in the following decision step ES_3 that the determined emission comparison value exceeds a predefined upper threshold value or falls below a predefined lower threshold value, which is symbolized by the decision path "yes", the on-board determination of the pollutant emission masses is detected as faulty in process step VS_5A and displayed, for example, by means of an error display and/or stored in an error memory assigned, for example, to the on-board monitoring system.

Subsequently, in process step VS_6, a total pollutant emission mass for the past operating period can be determined by integrating the pollutant emission masses continuously determined in VS_3 over the past operating period of the internal combustion engine. For this purpose, for example, the pollutant mass flow is integrated over the operating period.

In the following process step VS_7, an emission ratio value can then be formed from the total pollutant emission mass determined in VS_6 and an associated past operating time or a distance travelled during the operating time of a motor vehicle powered by the internal combustion engine or the energy converted over the operating time of the internal combustion engine

• - Ausgabe einer Warn- oder Fehlermeldung an einen Betreiber der Brennkraftmaschine und Abspeicherung dieser Fehlermeldung in einem Fehlerspeicher der elektronischen Steuerungsvorrichtung,
• - Beschränkung des Betriebs der Brennkraftmaschine auf Betriebsbereiche mit niedrigen Schadstoff-Emissionen,
• - Stilllegung der Brennkraftmaschine.

If it is then determined in decision step ES_4 that the respective emission ratio value determined in VS_7 exceeds a specified threshold, which is represented by the decision path "yes", at least one of the following measures can be initiated in process step VS_8:

• - issuing a warning or error message to an operator of the internal combustion engine and storing this error message in an error memory of the electronic control device,
• - Restriction of the operation of the internal combustion engine to operating ranges with low pollutant emissions,
• - Decommissioning of the internal combustion engine.

2 shows an internal combustion engine 1, which can be designed, for example, as a reciprocating piston internal combustion engine with four cylinders (indicated). The internal combustion engine 1 is supplied with an air-fuel mixture 10a from the intake side via an air-fuel mixture supply unit 10. The air-fuel mixture supply unit 10 represents, for example, a fuel injection system in conjunction with a throttle valve, which is connected to the electronic control device 7 via signal lines 8 and is controlled such that an air-fuel mixture 10a in a predetermined quantity and composition is supplied to the combustion chambers of the internal combustion engine 1. Thus, the electronic control device can influence both the power provided and the composition of the exhaust gas stream 11a, in particular the so-called lambda value, which provides information about the oxygen content in the exhaust gas stream 11a.

Connected to the exhaust side of the internal combustion engine 1 is an exhaust gas aftertreatment device 2 comprising a first exhaust gas catalyst 3, a second exhaust gas catalyst 4, and a particulate filter 5, which are connected to the internal combustion engine 1 and interconnected via an exhaust pipe 11. This exhaust gas aftertreatment device 2 corresponds to a conventional design for a gasoline internal combustion engine, but is not necessarily required in this configuration for carrying out the method according to the invention. It is explicitly pointed out that the methods and subject matter according to the invention can also be used with deviating configurations of internal combustion engines and exhaust gas aftertreatment devices, such as those used in diesel internal combustion engines. Of particular importance, however, is the exhaust gas sensor 6c at the outlet of the exhaust gas aftertreatment device 2, through which the exhaust gas stream 11a is released into the environment after aftertreatment has taken place.

The exhaust gas flow 11a is guided through the exhaust pipe 11 to the aforementioned components of the exhaust gas aftertreatment device 2. The exhaust gas flow 11a is represented by arrow symbols that indicate the flow direction of the exhaust gas flow 11a. The first exhaust gas catalyst 3 is arranged close to the engine, directly at the exhaust outlet of the internal combustion engine 1, and is designed here, for example, as a three-way catalyst (TWC). Downstream of the first exhaust gas catalyst 3, based on the exhaust gas flow 11a, there is first a particulate filter 5, which is designed, for example, as a gasoline particulate filter (GPF), and then the second exhaust gas catalyst 4, which can also be designed as a three-way catalyst (TWC) and, for example, as a so-called underbody catalyst. (UbKat) can be arranged on the underbody of a motor vehicle.

In the exhaust pipe 11, a first exhaust gas sensor 6a is arranged upstream of the first exhaust gas catalytic converter 3, a second exhaust gas sensor 6b is arranged downstream of the first exhaust gas catalytic converter 3, and a third exhaust gas sensor 6c is arranged downstream of the second exhaust gas catalytic converter 4 in the exhaust gas flow 11a. A temperature sensor 9 for measuring the temperature of the exhaust gas flow 11a is also arranged in the exhaust pipe 11 between the first exhaust gas catalytic converter 3 and the particulate filter 5. The pressure drop across the particulate filter 5, which provides information about the soot load of the particulate filter 5, is determined by means of a differential pressure sensor Δp.

The aforementioned sensors 6a-c and 9 are connected via electrical signal lines 8 to the input/output interface 7c of an electronic control device 7 according to the invention for transmitting the sensor signals to the control device 7. The air-fuel mixture supply unit 10 of the internal combustion engine 1 is also connected via electrical signal lines 8 to the input/output interface 7c of the electronic control device 7 according to the invention.

The electronic control device 7 has an electronic processing unit 7a, also referred to as a processor, an electronic storage device 7b, and an input/output interface 7c. In this embodiment, the electronic storage device 7b comprises a program memory 7b1 in which a computer program product 20 according to the invention with program instructions is available. Furthermore, the electronic storage device 7b has an operating data memory 7b2 in which predefined operating data 21 as well as operating data acquired during operation are stored, for example, organized in characteristic maps.

The electronic processing unit 7a is configured to carry out the method according to the invention in the previously described and possibly additional embodiments. For this purpose, the electronic processing unit 7a has access to, or is in data communication with (symbolized by connecting arrows) the input/output interface 7c, the program memory 7b1, and the operating data memory 7b2. Upon execution of the program instructions by means of the electronic processing unit 7a, using the relevant operating parameters and various threshold values for, e.g., pollutant emission masses, emission comparison values, or emission ratio values based on the total pollutant emission mass and the distance traveled, the electronic control device 7 is prompted to execute the method according to the invention for on-board determination of pollutant emission masses of an internal combustion engine 1, possibly while simultaneously executing a lambda control of the fuel-air mixture 10a supplied to the internal combustion engine 1 during operation.

According to the program instructions, sensor data or operating parameters BePa, for example, the signals from exhaust gas sensors 6a-c, AS_Sig, which represent the pollutant content and/or the oxygen content in exhaust gas stream 11a, and signals from temperature sensor 9, are received via the input/output interface 7c and, if applicable, stored in the operating data memory 7b2 as operating data 21. The program-specified arithmetic operations for on-board determination of pollutant emission masses are executed according to the method according to the invention. Based on this, control commands, for example for controlling the air-fuel mixture 10a, are then output to the air-fuel mixture supply unit 10 of the internal combustion engine 1.

To carry out the method for on-board determination of pollutant emission masses, in particular the sensor signal values, AS_Sig, which are provided by the exhaust gas sensor 6c and which are representative of a concentration of at least one pollutant in the exhaust gas flow 11a of the internal combustion engine (1) released into the environment, are used.

List of reference symbols

1

internal combustion engine

2

Exhaust aftertreatment device

3

first catalytic converter

4

second exhaust catalyst

5

Particle filter

6a - c

Exhaust gas sensors

7

electronic control device

7a

Electronic computing unit

7b

Electronic storage device

7b1

Program memory

7b2

Operating data storage

7c

Input/output interface

8

Signal lines

9

Temperature sensor

10

Air-fuel mixture supply unit

10a

Air-fuel mixture

11

exhaust pipe

11a

Exhaust gas flow

20

computer program product

21

Operating data

GPF

Gasoline particulate filter

Δp

Pressure difference sensor

TWC

Three-way catalyst

UbKat

Underbody catalyst

AS_Sig

Sensor signal values

BePa

Operating parameters

VS_1-8(A, B)

Procedural steps

ES_1-4

Decision-making steps

Claims (14)

Method for the on-board determination of pollutant emission masses of an internal combustion engine (1) with an exhaust gas aftertreatment device (2), wherein the method is carried out by means of an electronic control device (7) assigned to the internal combustion engine (1) and/or the exhaust gas aftertreatment device (2), wherein sensor signal values (AS_Sig) provided by at least one exhaust gas sensor (6c), which are representative of a concentration of at least one pollutant in the exhaust gas flow (11a) of the internal combustion engine (1), are detected and wherein, on the basis of these sensor signal values (AS_Sig), pollutant emission values are continuously determined and wherein the pollutant emission masses are calculated during operation of the internal combustion engine (1) on the basis of the pollutant emission values, characterized in that the determined pollutant emission values are stored in a memory area of the electronic control device (7) as a function of operating parameter ranges of the internal combustion engine (1) and/or the exhaust gas aftertreatment device (2) in emission value groups and that, on the basis of these emission value groups, the respective Pollutant emission substitute values associated with operating parameter ranges are determined, wherein the pollutant emission substitute values are used as a substitute for determining the pollutant emission masses during operation, depending on the operating parameter ranges of the internal combustion engine (1) and/or the exhaust gas aftertreatment device, if temporarily no or only implausible sensor signal values (AS_Sig) and thus no usable, current pollutant emission values are available. Procedure according to Claim 1 , wherein, if the pollutant emission masses exceed a predetermined threshold value, at least one of the following measures is initiated: - issuing a warning or error message to an operator of the internal combustion engine - storing a warning or error message in an error memory of the electronic control device, - restricting the operation of the internal combustion engine (1) to operating ranges with low pollutant emissions, - shutting down the internal combustion engine (1). Procedure according to Claim 1 or 2 , wherein the pollutant emission values determined on the basis of the sensor signal values (AS_Sig) for a respective operating parameter range are compared or related to the pollutant emission substitute values for the respective operating parameter range and an emission comparison value is thus determined, wherein the on-board determination of the pollutant emission masses is recognized as faulty and displayed if the determined emission comparison value exceeds a predetermined upper threshold value or falls below a predetermined lower threshold value. Method according to one of the preceding claims, wherein the pollutant emission substitute values assigned to the operating parameter ranges are determined by applying at least one of the following methods to the stored pollutant emission values of the assigned emission value groups: - calculation of an average value, - filtering, weighting and bundling, - statistical evaluation. Method according to one of the preceding claims, wherein a total pollutant emission mass for the past operating period is determined by integrating the pollutant emission masses continuously determined over a past operating period of the internal combustion engine (1). Procedure according to Claim 5 , whereby an emission ratio value is formed from the total pollutant emission mass and an associated past operating time or a distance travelled during the operating time by a motor vehicle powered by the internal combustion engine or the energy converted over the operating time of the internal combustion engine. Procedure according to Claim 6 , wherein, if the respective emission ratio value exceeds a predetermined threshold value, at least one of the following measures is initiated: - issuing a warning or error message to an operator of the internal combustion engine (1) and storing this error message in an error memory of the electronic control device (7), - restricting the operation of the internal combustion engine (1) to operating ranges with low pollutant emissions, - shutting down the internal combustion engine (1). Method according to one of the preceding claims, wherein the operating parameter ranges are delimited by values or value ranges of at least one of the operating parameters: - current speed of the internal combustion engine (1), - currently output power/load of the internal combustion engine (1), - current intake air mass flow, - current boost pressure in the intake tract, - current supplied fuel mass, - current exhaust gas recirculation flow, - current operating temperature of the internal combustion engine (1), - current operating temperature of the exhaust gas aftertreatment device (2), - exhaust gas temperature upstream of the exhaust gas aftertreatment device (2), - exhaust gas temperature downstream of the exhaust gas aftertreatment device (2), - size of the exhaust gas flow, - ambient temperature. Procedure according to Claim 8 , wherein the values or value ranges of the respective operating parameter(s) delimiting a respective operating parameter range are variable over the operating time of the internal combustion engine (1). Method according to one of the preceding claims, wherein a pollutant emission value determined on the basis of the sensor signal values (AS_Sig) is stored in parallel in several, in particular two adjacent emission value groups. Method according to one of the preceding claims, wherein pollutant emission values from several, in particular from two or three adjacent emission value groups are linked to determine a pollutant emission replacement value of an operating parameter range. Method according to one of the preceding claims, wherein the method can be applied both with respect to individual pollutants in the exhaust gas stream (11a) and with respect to pollutant sum values of several pollutants in the exhaust gas stream (11a). Electronic control device (7) for operating an internal combustion engine (1) with an exhaust gas aftertreatment device (2), comprising at least - an electronic storage device (7b) in which at least one computer program product (20) with program instructions is provided, and - an input/output interface (7c) configured to receive and output electrical signals, and - an electronic computing unit (7a) for executing the program instructions, with access to the at least one electronic storage device (7b) and the input/output interface (7c); wherein the program instructions, when executed by means of the electronic computing unit (7a), cause the electronic control device (7) to execute the method according to one of the preceding claims. Computer program product (20) for operating an internal combustion engine (1) with an exhaust gas aftertreatment device (2), comprising program instructions for execution by the electronic processing unit (7a) of the electronic control device (7) according to Claim 13 , wherein the program instructions, when executed by the electronic computing unit (7a), cause the electronic control device (7) to carry out the method according to one of the Claims 1 until 12 to carry out.