Diagnostic process and diagnostic procedure for checking the correct integration state of an exhaust aftertreatment element of an exhaust system, exhaust system, internal combustion engine and motor vehicle

Abstract

The invention relates to a diagnostic process (D) for checking whether an exhaust aftertreatment element is correctly seated in its emission element installation location and correctly integrated into an exhaust system. An exhaust gas mass value (MA) characterizing the exhaust gas mass emitted from the internal combustion engine between a start time and a diagnostic time is determined. At the start time, an exhaust gas temperature prevailing downstream of the emission element installation location is detected by means of an exhaust gas temperature sensor, and a corresponding start exhaust gas temperature value (T1) is provided. Furthermore, an exhaust gas temperature prevailing at the temperature measuring point after the start time is detected by means of the same exhaust gas temperature sensor, and a corresponding exhaust gas temperature value (T2) is provided. An exhaust gas temperature difference value (T21) is calculated from T2 and T1.At the diagnostic point, which occurs as soon as the exhaust gas temperature difference value (T21) is equal to or greater than a specified limit exhaust gas temperature difference value (GT), the following is determined: - that the exhaust mass value (MA) is equal to or greater than a specified limit exhaust mass value (GM), whereupon an initial diagnostic signal (DS1) is provided, which characterizes a correct integration state of the emission element, or - that the exhaust mass value (MA) is smaller than the specified limit exhaust mass value (GM), whereupon a second diagnostic signal (DS2) is provided, which characterizes an incorrect integration state of the emission element.

Description

[0001] The present invention relates to a diagnostic process and a diagnostic method, each for checking whether an exhaust aftertreatment element – ​​referred to herein as an emission element – ​​is correctly, and in particular in accordance with regulations, integrated into an installation location provided for the exhaust aftertreatment element, i.e., an emission element installation location, and consequently correctly or in accordance with regulations into an exhaust system coupled to an internal combustion engine. Furthermore, the invention relates to an exhaust system for an internal combustion engine, wherein the exhaust system is configured to carry out the diagnostic process or the diagnostic method. In addition, an internal combustion engine comprising the exhaust system and a motor vehicle comprising the exhaust system or the internal combustion engine are proposed.

[0002] Legislation establishes requirements for the marketing and operation of motor vehicles, including permissible maximum values ​​for emissions released into the environment by the operation of the vehicle, particularly its internal combustion engine. To ensure the efficient functioning of motor vehicle exhaust aftertreatment systems, measures are also prescribed to monitor the operational readiness of these devices, at least to verify that the relevant exhaust aftertreatment system is correctly installed in its designated location and that the exhaust gas stream emitted from the internal combustion engine flows correctly through the exhaust aftertreatment system.

[0003] For example, DE 10 2014 209 794 A1 proposes a method for diagnosing the removal of an exhaust gas purification component in the exhaust system of an internal combustion engine. Furthermore, DE 10 2014 226 675 A1 proposes a method for monitoring a methane oxidation catalyst in an exhaust aftertreatment system of an internal combustion engine, wherein liquid fuel is injected upstream of the methane oxidation catalyst and its behavior in relation to the injected fuel is observed. This enables the detection of methane oxidation catalyst removal. Another conventional method for checking a particulate filter in the exhaust system of an internal combustion engine with an exhaust gas turbocharger, whereby particulate filter removal is detected by means of pressure changes, is disclosed in DE 10 2018 005 111 A1.

[0004] Furthermore, a method for determining the presence of a particulate filter in the exhaust system of an internal combustion engine is known from DE 10 2018 222 247 A1 and US 2011 / 0 143 449 A1. JP 2020-112 039 A1 discloses a method for detecting the detachment of an exhaust pipe from an exhaust aftertreatment device.

[0005] The object of the present invention is to create a particularly simple and reliable way to check – especially on board a motor vehicle – that an exhaust aftertreatment element is correctly integrated into an exhaust system.

[0006] This problem is solved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and possible embodiments set forth in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, across categories and embodiments as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the dependent claims.

[0007] According to the invention, a diagnostic process (D) and a diagnostic method (V) are proposed for checking whether an exhaust aftertreatment element, i.e., an emission element, is correctly integrated into its emission element installation location in an exhaust system coupled to a heat engine, in particular an internal combustion engine. The diagnostic method (V) comprises a release process (F) in which a predetermined release state of the exhaust system and / or the internal combustion engine is determined, and the diagnostic process (D) is executed in response to the presence of the release state. Furthermore, according to the invention, an exhaust system is proposed which has an exhaust duct connectable to a combustion chamber arrangement of the heat engine / internal combustion engine and has an emission element installation location for the emission element.Although this document primarily focuses on connecting the exhaust system to an internal combustion engine, it should be understood that this connection is merely exemplary; the exhaust system can be connected to any type of heat engine, including stationary heat engines such as gas turbines, etc. When the emission element is correctly positioned in its installation location, it is properly integrated fluidically into the exhaust duct. In such a properly functioning state, the emission element is designed to allow exhaust gas to flow through it during operation of the exhaust system or the internal combustion engine, thus reducing emissions. The exhaust system also includes a control unit configured to perform the diagnostic process or procedure, which constitutes a further aspect of the present invention.Furthermore, the present invention proposes a heat engine, in particular an internal combustion engine, which is designed, for example, as a gasoline or diesel engine and includes an exhaust system. Thus, for the heat engine / internal combustion engine according to the invention, the exhaust system is fluidically connected to the combustion chamber assembly. The invention also proposes a motor vehicle assembly for manufacturing a motor vehicle, or a motor vehicle itself, each with the exhaust system and / or the internal combustion engine on board.

[0008] The diagnostic process and / or diagnostic method according to the invention can be a computer-implemented method. In this case, the exhaust system has means configured to execute steps of the corresponding computer-implemented method. The control unit for the exhaust system is then, in particular, equipped for electronic data processing, i.e., a computer unit. The invention further includes a computer program which, upon execution of its program commands by the exhaust system or control unit, causes the exhaust system to execute the diagnostic process or diagnostic method. The invention also proposes a computer-readable storage medium on which the computer program is stored.

[0009] In this context, an emission element is understood to be a device that—when the exhaust system is properly and fully operational—is integrated into the exhaust system, for example, into its exhaust duct, and functions as an exhaust aftertreatment element. By means of the emission element, at least one component of the emissions emitted during operation (i.e., during normal operation) of the internal combustion engine is reduced and / or captured on board the vehicle. These emissions are primarily exhaust gas and noise emissions. Examples of exhaust aftertreatment or emission elements include: a three-way catalytic converter, a NOₓ filter, and a CO₂ filter. x- Storage catalyst, a (gasoline or diesel) particulate filter, an oxidation catalyst, an SCR catalyst, an exhaust gas recirculation system, an acoustic silencer, etc. The emission element, in particular an outer wall element of the emission element, is permeable to exhaust gas. A reaction element of the emission element that directly reduces emissions from the exhaust gas is located in the outer wall element, such as a washcoat, a sound-absorbing material, etc.

[0010] The diagnostic process (D) according to the invention comprises, in particular, a diagnostic process start step in which a diagnostic process start signal is awaited, and further steps of the diagnostic process are executed as soon as the diagnostic process start signal is / has been detected in the diagnostic process start step. The diagnostic process start signal is provided, for example, by the provision of an internal combustion engine activation signal, which is sent to the internal combustion engine to activate its firing operation. Furthermore, it can be provided that the diagnostic process signal is provided by means of the release process preceding the diagnostic process, as will be explained in more detail below. In the diagnostic process according to the invention, an exhaust gas mass value is determined, which characterizes the exhaust gas mass emitted from the internal combustion engine between a start time and a diagnostic time.

[0011] Furthermore, in the diagnostic process, an exhaust gas temperature difference value is calculated from a starting exhaust gas temperature value and an exhaust gas temperature value. The starting exhaust gas temperature value characterizes the initial exhaust gas temperature present at a temperature measurement point downstream of the emission element installation location at the start of the diagnostic process. The exhaust gas temperature value characterizes the current exhaust gas temperature present at the temperature measurement point after the start of the process. A diagnostic point in the diagnostic process occurs as soon as the exhaust gas temperature difference value equals or exceeds a predefined or predefinable limit value. This means that from the start of the process, the exhaust gas temperature value is recorded repeatedly until the exhaust gas temperature difference value first equals or exceeds the limit value.

[0012] The limiting exhaust gas temperature difference is specified, in particular based on the initial exhaust gas temperature. It can, for example, be read from a characteristic curve or map over the initial exhaust gas temperature or calculated using a function based on the initial exhaust gas temperature. The initial exhaust gas temperature and the current exhaust gas temperature are each measured by an exhaust gas temperature sensor, the sensor of which is located in or at the temperature measuring point. The sensor is therefore in direct contact with the emission element installation location, in particular with the outer tube surrounding the reaction element, and / or is located directly in the exhaust gas flow path (so that the sensor is directly exposed to or surrounded by exhaust gas). Depending on the temperature prevailing in / at the temperature measuring point, the exhaust gas temperature sensor provides a corresponding sensor signal, the respective temperature value.

[0013] As part of the diagnostic process, at least one first, second, or third diagnostic signal is provided. The first or second diagnostic signal is provided at or after the point of diagnosis. Conversely, as long as the exhaust gas temperature difference is less than the limit value, i.e., the point of diagnosis has not yet been reached, neither the first nor the second diagnostic signal is output. However, it is conceivable that a third diagnostic signal is output before the point of diagnosis, which will be explained in more detail below. The first diagnostic signal indicates a correct integration state of the emission element, meaning that it is correctly (and in particular, legally compliant) integrated into its installation location within the exhaust system.In contrast, the second diagnostic signal indicates an incorrect integration state of the emission element, meaning it is incorrectly, incompletely, or not at all integrated into the emission element installation location. The first diagnostic signal, characterizing the correct integration state of the emission element, is provided during the diagnostic process when it is determined that the exhaust gas mass value is equal to or greater than a predefined or predefinable limit value. Conversely, the second diagnostic signal, characterizing the incorrect integration state of the emission element, is provided during the diagnostic process when it is determined that the exhaust gas mass value is less than the predefined limit value.

[0014] In particular, in response to the provision of the first diagnostic signal, a user of the exhaust system, for example, a user / driver of the vehicle equipped with the internal combustion engine, receives an initial notification informing them of the correct integration status of the emission element. Even the extinguishing of a warning light in the instrument cluster after an initial light test, which occurs, for example, before / during the activation of the combustion engine, is considered a possible example of an initial notification. In response to the provision of the second diagnostic signal, a second notification can be provided to the user / driver, informing them of the incorrect integration status of the emission element.The failure of the warning light to extinguish or its illumination after the initial illumination test is considered a possible example of a second notification. Alternatively or additionally, it may be stipulated that the provision of the second diagnostic signal may be used to specifically prevent the unrestricted operation of the internal combustion engine and / or the unrestricted operation of a motor vehicle equipped with the internal combustion engine. This targeted prevention of the unrestricted operation of the internal combustion engine and / or the motor vehicle may include one or more of the following sanctions (this list is not exhaustive): - Notifying the user of the motor vehicle, in particular on a regular or continuous basis, - Limiting the operating time of the internal combustion engine coupled to the exhaust system to a predetermined remaining emergency operating time, - Limiting the crankshaft power that can be provided by the internal combustion engine to a lower level than that provided for by the rated power of the internal combustion engine, - Limiting the driving range of a motor vehicle equipped with an exhaust system to a predetermined remaining range, - Deactivating / switching off the internal combustion engine at the end of the emergency running time and / or at the time the end of the specified remaining range is reached, - Preventing the activation or starting of the internal combustion engine, especially after the end of the emergency running time and / or at the time the end of the specified remaining range is reached.

[0015] The invention is based on the idea that, in the intended installation position or with correct integration of the emission or exhaust aftertreatment element, and at least during a cold start phase of the internal combustion engine, energy is extracted from the exhaust gas mass flow passing through the emission element. This is because the emission element is heated by the exhaust gas mass flow, i.e., heat is transferred from the exhaust gas to a material mass of the emission element. Consequently, the exhaust gas mass flow loses heat or energy as it passes through the emission component. However, if the emission or exhaust aftertreatment element is not integrated into the exhaust gas flow, or is not integrated correctly, then consequently less material mass is heated by the same exhaust gas mass flow.Therefore, the exhaust gas mass flow downstream of the emission element installation point has more energy, meaning it has lost less energy, than if the emission element were correctly installed and consequently subjected to the exhaust gas mass flow. This provides a starting point for investigating the integration state of the emission element. An incorrect integration state could arise, for example, if the vehicle, originally correctly equipped with the emission element, had an accident—perhaps unnoticed—in which the emission element or the exhaust system was damaged. Naturally, the diagnostic process can also detect (impermissible) avoidance of the emission element.Such avoidance can be achieved impermissibly, for example, by removing the emission element from the exhaust system or modifying a section of the exhaust system (so that the exhaust gas is released upstream of the emission element or routed around the emission element's installation location via an impermissible bypass). By evaluating a signal curve provided by the exhaust gas temperature sensor downstream of the emission element or at the temperature measuring point, in conjunction with the exhaust gas mass value, it is possible to check whether the emission element is correctly integrated into the exhaust gas flow or not – at least if the initial exhaust gas temperature at the start of the diagnostic process is lower than the first measured exhaust gas temperature, for example, during the cold start phase of the internal combustion engine.

[0016] According to a possible further development, only sensor signals from the exhaust gas temperature sensor located downstream of the emission element installation location are fed into the diagnostic process. This means that a single exhaust gas temperature sensor located downstream of the emission element installation location is sufficient to execute the diagnostic process as intended. In this context, a possible further development of the exhaust system stipulates that exactly one of its exhaust gas temperature sensors integrated into the exhaust duct is wirelessly and / or wired connected to the control unit, with said exhaust gas temperature sensor being located downstream of the emission element installation location. It is possible that the exhaust system has only this exhaust gas temperature sensor, but no other exhaust gas temperature sensors. Using only one exhaust gas temperature sensor makes the diagnostic process particularly easy to execute.

[0017] According to another possible embodiment, the limiting exhaust gas mass value is predefined based on the starting exhaust gas temperature. In other words, the limiting exhaust gas mass value can be set to a different value depending on the detected or measured starting exhaust gas temperature. For example, the limiting exhaust gas mass value is read from a characteristic curve or map over the starting exhaust gas temperature or calculated using a function based on the starting exhaust gas temperature. This allows the limiting exhaust gas mass value to be adapted particularly efficiently to the current starting operating temperature of the internal combustion engine or to the current starting exhaust gas temperature.

[0018] Another possible configuration of the diagnostic process involves determining the exhaust gas mass value by integrating an exhaust gas mass flow signal, which characterizes the exhaust gas mass flow, over time between the start time and the diagnostic time. This is advantageous because it allows for a particularly simple and cost-effective determination of a value characterizing the exhaust gas mass.

[0019] One possible further development approach involves predefining the exhaust gas mass limit based on the exhaust gas mass value. In other words, the exhaust gas mass limit can be set to a different value depending on the detected or measured exhaust gas mass. For example, the exhaust gas mass limit can be read from a characteristic curve or map over the exhaust gas mass, or calculated using a function based on the exhaust gas mass. This allows the exhaust gas mass limit to be adapted particularly efficiently to the current energy content of the exhaust gas emitted from the internal combustion engine.

[0020] The reliability of the diagnostic process can be further increased by low-pass filtering the exhaust gas mass flow signal used to define the limit value, as provided in another possible embodiment, and by setting the limit value based on this low-pass filtered signal. In this way, localized, short-term, or rapidly transient increases in exhaust gas energy, as well as any measurement error peaks, have no distorting effect on the limit value.

[0021] In another possible embodiment, the exhaust gas mass flow signal, which characterizes the exhaust gas mass flow, is acquired. The determination of the exhaust gas mass value is carried out by time-integrating the exhaust gas mass flow signal, and the limit value is specified based on this value, as long as the exhaust gas mass flow signal characterizes an exhaust gas mass flow that is less than a specified limit value. If, during the diagnostic process—especially before the diagnostic point—the exhaust gas mass flow signal characterizes an exhaust gas mass flow that is equal to or greater than the specified limit value, a third diagnostic signal is generated. This third diagnostic signal indicates an incomplete diagnostic process. The rationale behind this is that a sustained increase in exhaust gas energy, for example, due to a full-load demand, would distort the diagnostic process.Due to the presence of the third diagnostic signal, the diagnostic process start signal can be provided, or the system can jump to the beginning of the diagnostic process to restart it. Alternatively, based on the third diagnostic signal, the system can jump to the beginning of the release process of the diagnostic procedure. This design of the diagnostic process ensures that the first or the second diagnostic signal is provided with particular reliability, while advantageously minimizing the probability of providing an incorrect diagnostic signal (the first diagnostic signal even though the integration state of the emission component is correct, or vice versa).

[0022] Another possible configuration involves storing the first or second diagnostic signal in a diagnostic memory upon its generation and retaining it during subsequent runs of the diagnostic process, particularly until the next generation or generation of the (next) first or second diagnostic signal. The diagnostic memory (which can also be referred to as a fault memory) can be part of the exhaust system or the internal combustion engine coupled to the exhaust system, especially the respective control unit. For example, generating the third diagnostic signal could involve generating the diagnostic signal generated most recently or in the previous run of the diagnostic process.It may be provided that the most recently provided diagnostic signal, and consequently stored in the diagnostic memory, is provided as a third diagnostic signal or together with the third diagnostic signal. It is specifically provided that—as long as the second diagnostic signal is stored in the diagnostic memory—the respective unrestricted operation of the internal combustion engine and / or the motor vehicle is specifically prevented. Furthermore, it is specifically provided that the second diagnostic signal stored in the diagnostic memory is only deleted from the diagnostic memory when the first diagnostic signal is / has been provided by means of another, complete cycle of the diagnostic process.

[0023] In the diagnostic procedure (V), a release process (F) is executed prior to the diagnostic process (D). This release process checks whether the exhaust system and / or the internal combustion engine is in the specified release state. The release process includes a release start step, in which the system waits for a release start signal. Further steps of the release process are executed as soon as this signal is detected. The release start signal is generated, for example, by an internal combustion engine activation signal, which is sent to the engine to activate its firing mode. If the release process determines that the release state is present, the diagnostic process is started.For example, based on the initial detection of the release state after the release process start signal, the diagnostic process start signal is provided. As explained above, the subsequent steps of the diagnostic process are then executed, since the diagnostic process start signal is detected during the release process start step of the diagnostic process. If, between the start time and the diagnostic time, the presence of the release state is detected again, the previously started diagnostic process run is not interrupted for a restart. Therefore, as soon as the release state is detected at any given time, the diagnostic process is triggered, and a release criterion determining the release state is established.Some or all of the release criteria are "forgotten," meaning they are not considered (further / again) at least for the duration of the initiated diagnostic process, particularly until the first, second, or third diagnostic signal has been provided. By determining the predefined release state before the diagnostic process, it is ensured that the exhaust system or the internal combustion engine is in a defined initial state at the time the diagnostic process is triggered, allowing for a reliable diagnostic process result and thus minimizing the probability of a false-positive or false-negative result.

[0024] In another possible embodiment of the diagnostic procedure, the release state has exactly one release criterion, and the release state exists when this single criterion is met. Alternatively, the release state can have two or more release criteria, and the release state exists when one necessary and one additional criterion, or the necessary criterion and two or more additional criteria, are met. Furthermore, it can be specified that the release state exists when all of its release criteria are met.

[0025] A first of the release criteria is considered fulfilled as soon as and as long as an outflow-side temperature difference, calculated from an initial outflow-side exhaust gas temperature prevailing downstream of the emission element installation location and an ambient temperature, is equal to or less than a predetermined or predefinable maximum outflow-side (first) temperature difference. The initial exhaust gas temperature is recorded, in particular, by means of the (especially the only) exhaust gas temperature sensor and consequently at the temperature measuring point, whereby the initial exhaust gas temperature can be an exhaust gas temperature or a temperature of a wall / body of the exhaust system, in particular the outer pipe surrounding the reaction element.

[0026] A second of the release criteria is considered fulfilled as soon as and as long as an inlet-side (second) temperature difference, calculated from an inlet-side initial exhaust gas temperature modeled upstream of the emission element installation location and an ambient temperature, is equal to or less than a specified or specifiable inlet-side maximum temperature difference. For example, the inlet-side initial exhaust gas temperature is modeled based on a non-operating time (duration of a continuously deactivated state) of the internal combustion engine in conjunction with the ambient temperature, in particular by means of a control unit, for example, that of the exhaust system, the internal combustion engine, or the motor vehicle.Alternatively, the inlet-side initial exhaust gas temperature can be detected by means of another temperature sensor, but it is preferred not to use any further temperature sensor arranged on the exhaust system other than said exhaust gas temperature sensor, in particular no further exhaust gas temperature sensor.

[0027] A third of the release criteria is considered fulfilled as soon as and as long as a cold-start heating element control module is operated in a cold-start heating mode for rapid heating of the exhaust system or the internal combustion engine. The cold-start heating element control module is specifically designed as a hardware control unit or a software control module. The cold-start heating element can be the internal combustion engine itself, for example, its fuel injection system. In other words, the third release criterion is fulfilled as soon as and as long as the internal combustion engine or the cold-start heating element control module is operated in a cold-start mode for controlling the cold-start heating element.

[0028] A fourth of the release criteria is considered fulfilled as soon as and as long as the engine temperature of the internal combustion engine remains within a specified or predefinable temperature range. This ensures that the exhaust gas currently emitted from the internal combustion engine is neither too hot nor too cold to obtain a reliable diagnostic process result.

[0029] A fifth release criterion is considered fulfilled as soon as and as long as the internal combustion engine is operated in a start-up mode for activation or starting. This can be achieved, for example, by detecting whether the internal combustion engine activation signal, which is sent to the engine to activate its firing operation, is present. It may be stipulated that this fifth release criterion is a necessary criterion for the release state.

[0030] According to another possible configuration of the diagnostic procedure, a third diagnostic signal is provided – particularly before the diagnostic process begins – which characterizes an incomplete diagnostic process as soon as the release process detects that the necessary release criterion, or one or more of the necessary release criteria, can no longer be met in a current operating cycle of the internal combustion engine, especially the third and / or the fifth release criterion. Alternatively or additionally, a third diagnostic signal is provided – particularly before the diagnostic process – which characterizes an incomplete diagnostic process as soon as the diagnostic process detects that the control module of the cold start heating system has deactivated or is deactivating the cold start heating mode between the start time and the diagnostic time.This ensures that the diagnostic process is not unnecessarily started or advanced if, in the current usage cycle of the internal combustion engine, a reliable diagnostic process result cannot be expected or is no longer to be expected due to an excessively high exhaust gas temperature and / or an excessively low exhaust gas temperature difference.

[0031] Further features of the invention may become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures themselves, can be used not only in the combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0032] The drawing shows in Fig. 1. A flowchart illustrating a diagnostic procedure for checking whether an emission element is correctly integrated into its emission element installation location of an exhaust system coupled to an internal combustion engine, wherein the diagnostic procedure includes a release process and a diagnostic process, and in Fig. 2. To illustrate a possible design of the diagnostic procedure, a control model is shown, which was generated using modeling software for modeling physical systems, in this case Matlab Simulink, wherein Fig. 2 the Fig. 2a, Fig. 2b, Fig. 2c, Fig. 2d and Fig. 2e.

[0033] The following describes a diagnostic procedure V for checking whether an emission element is correctly integrated into its emission element installation location in an exhaust system coupled to an internal combustion engine, as well as an exhaust system, an internal combustion engine comprising the exhaust system, and a motor vehicle comprising the exhaust system or the internal combustion engine. The exhaust system, internal combustion engine, and motor vehicle are not shown in the figures.

[0034] The vehicle features an internal combustion engine on board, serving as a traction motor and / or as a generator drive for an electromechanical converter for electrically charging the vehicle's traction battery. Therefore, the vehicle is a hybrid-electric or purely combustion-engine capable vehicle. An exhaust duct of the exhaust system is fluidically connected to a combustion chamber arrangement of the internal combustion engine, so that during operation, exhaust gas emitted from the engine flows into the exhaust system or its exhaust duct. The exhaust duct has an emission element installation location for an emission element, which, when correctly positioned, is fluidically integrated into the exhaust duct. The emission element is an exhaust aftertreatment device.-cleaning element by means of which at least one emission component emitted during the firing operation of the internal combustion engine is reduced and / or captured on board the motor vehicle, in particular in the exhaust system.

[0035] The exhaust system also includes a control unit configured to perform diagnostic procedure V. In this case, the exhaust system has exactly one exhaust gas temperature sensor, which is coupled or can be coupled to the control unit. This exhaust gas temperature sensor is located downstream of the emission element installation location at / in a temperature measuring point. A temperature probe of the exhaust gas temperature sensor is in direct contact with the emission element installation location, in particular with the outer tube surrounding the reaction element, and / or is located directly in the exhaust gas flow path (so that the temperature probe is directly exposed to or surrounded by exhaust gas). The exhaust gas temperature sensor downstream of the emission element installation location detects the current temperature at the temperature measuring point (i.e., the exhaust gas temperature or the temperature of the exhaust system) and provides a temperature signal corresponding to this current temperature.It is possible that the exhaust system has two or more exhaust gas temperature sensors located upstream and / or downstream of the emission element.

[0036] It is in Fig. It can be seen that the diagnostic procedure V, according to the present example, comprises the release process F and the diagnostic process D, which can also be referred to as sub-processes F and D of the diagnostic procedure V. In the diagnostic procedure V, a first diagnostic signal DS1 or a second diagnostic signal DS2 is output by means of the diagnostic process D. The first diagnostic signal DS1 indicates a correct integration state of the emission element, whereas the second diagnostic signal DS2 indicates an incorrect integration state of the emission element. Furthermore, in the diagnostic procedure V, a third diagnostic signal DS3 can be output by means of the release process F and / or by means of the diagnostic process D, which indicates that the diagnostic procedure V has not been completed or has not been fully executed. The signals DS1, DS2, and DS3 are explained in more detail below.

[0037] The release process F of the diagnostic procedure V includes, in particular, a start step SF, which in this example constitutes the start step of the diagnostic procedure V. In the start step SF, the system waits for a release process start signal FPS, and further steps of the diagnostic procedure V, especially the release process F, are executed as soon as the release process start signal FPS is / has been detected. The release process start signal FPS is provided, for example, by the provision of an internal combustion engine activation signal, which is sent to the engine to activate its operation. Alternatively or additionally, the release process start signal FPS can be provided by other signals related to the operation of the internal combustion engine or the vehicle, such as the receipt of an unlock signal for unlocking the vehicle, etc.

[0038] In response to the release process start signal FPS, the release process F checks whether a predefined release state exists. If release process F determines that the release state exists, diagnostic process D is started or executed. In this example, a diagnostic process start signal DPS is provided in response to the initial detection of the release state after the release process start signal, whereupon diagnostic process D is started. The predefined release state characterizes a defined initial state of the system comprising the internal combustion engine and the exhaust system, thus ensuring a reliable diagnostic process result.

[0039] In this example, the release status has five release criteria that must be met for the release status to be established. Whether the release criteria are met is checked using queries A0-A4. Query A0 (see Fig. 1 and Fig. 2a) It is checked whether the first of the release criteria is considered fulfilled. For this purpose, the exhaust gas temperature sensor at the temperature measuring point records the current initial exhaust gas temperature on the outlet side (or a corresponding initial exhaust gas temperature TI1). The ambient temperature (or a corresponding ambient system temperature value TU) is also recorded. From the initial exhaust gas temperature value TI1 and the ambient system temperature value TU, an initial temperature difference value DTI1 on the outlet side is calculated, which is compared with a predefined maximum initial temperature difference value GTI1 on the outlet side. The first release criterion is considered fulfilled as soon as and as long as the initial temperature difference value DTI1 on the outlet side is equal to or less than the maximum initial temperature difference value GTI1.As long as - and only as long as - the first release criterion is met, a first release bit_0 (bit0) retains the value 1.

[0040] Using query A1 (see Fig. 1 and Fig. 2a) It is checked whether a second of the release criteria is considered fulfilled. For this purpose, a current inlet-side initial exhaust gas temperature is modeled upstream of the emission element installation location, and a corresponding inlet-side initial exhaust gas temperature value TI2 is provided. In addition, the ambient temperature or the ambient system temperature value TU is recorded. From the inlet-side initial exhaust gas temperature value TI2 and the ambient system temperature value TU, an inlet-side initial temperature difference value DTI2 is then determined, which is compared with a predefined inlet-side (second) maximum initial temperature difference value GTI2. The second release criterion is considered fulfilled as soon as and as long as the inlet-side initial temperature difference value is equal to or less than the second maximum initial temperature difference value. As long as—and only as long as—the second release criterion is fulfilled, a second release bit_1 (bit1) retains the value 1.

[0041] Using query A2 (see Fig. 1 and Fig. 2a) It is checked whether a third release criterion is considered fulfilled. For this purpose, a cold start heating element control module for controlling a cold start heating element of the exhaust system or the internal combustion engine is monitored with regard to its current operating mode. The third release criterion is considered fulfilled as soon as and as long as it is detected that the cold start heating element control module is operating in a cold start heating mode for rapid heating of the exhaust system. As long as—and only as long as—the third release criterion is fulfilled, a third release bit_2 (bit2) retains the value 1. It may be stipulated that the third release criterion is a necessary criterion for the release state.

[0042] Using query A3 (see Fig. 1 and Fig. 2b) It is checked whether a fourth release criterion is considered fulfilled. For this purpose, the engine temperature TM of the internal combustion engine is recorded and a corresponding engine temperature value is provided. The fourth release criterion is considered fulfilled as soon as and as long as it is recorded that the engine temperature value lies within a predefined engine temperature range, which is defined, for example, by a maximum engine temperature value TM1 and a minimum engine temperature value TM2. As long as—and only as long as—the fourth release criterion is fulfilled, a fourth release bit_3 (bit3) retains the value 1.

[0043] Using query A4 (see Fig. 1 and Fig. 2b) It is checked whether a fifth release criterion is considered fulfilled. For this purpose, the internal combustion engine is monitored with regard to its current operating mode. The fifth release criterion is considered fulfilled as soon as and as long as it is detected that the internal combustion engine is operating in a start-up mode to activate its powered operation (i.e., to start). As long as—and only as long as—the fifth release criterion is fulfilled, a fifth release bit (bit4) retains the value 1. It may be stipulated that the fifth release criterion is a necessary criterion for the release state.

[0044] One can recognize in Fig. 1. As long as the respective query A0-A4 does not record that the corresponding release criterion is met, the system continues to check for the existence of the respective release criterion. This is achieved using a suitable evaluation logic AL (see also...). Fig. 2c), in this example of a bitwise OR operator, it is determined whether, from the execution of the start step SF, all enable bits bit0, bit1, bit2, bit3, bit4 have simultaneously assumed the value 1. Additionally, a time is recorded at which all enable bits bit0, bit1, bit2, bit3, bit4 first simultaneously assumed the value 1 from the execution of the start step SF. This records an enable time at which the enable state for a run of the diagnostic procedure V or the enable process F is first present. Based on the detection of the enable state, a diagnostic process start signal DPS is provided in the diagnostic procedure V via the enable process F. It is also conceivable to specify, using a codeword CW, which of the enable bits bit0, bit1, bit2, bit3, bit4 are relevant for the enable state.This makes it possible, for example, to specify that the enable state is considered to exist as soon as exactly one of the enable bits bit0, bit1, bit2, bit3, bit4 has the value 1. Alternatively, the codeword CW can be used to specify that two or more of the enable bits bit0, bit1, bit2, bit3, bit4 must have the value 1 for the enable state to be detected, for example, one required bit and one additional bit, or the required bit and two or more additional bits. Furthermore, the codeword CW can be used to specify that the enable state is only considered to exist if all enable bits bit0, bit1, bit2, bit3, bit4 have the value 1. Those enable bits bit0, bit1, bit2, bit3, bit4 that are considered irrelevant for determining the enable state are permanently assigned the value 1 in the codeword CW.Due to the bitwise OR operator, only those of the enable bits bit0, bit1, bit2, bit3, bit4 that are set to 0 in the codeword CW have an influence on the enable state.

[0045] The third diagnostic signal DS3, which characterizes an incomplete or incomplete diagnostic procedure V, in this case an incomplete release process F, is provided when, or as soon as, the release process F detects that the necessary release criterion, or one or more of the necessary release criteria, can no longer be met in a current operating cycle of the internal combustion engine (i.e., until the internal combustion engine is restarted), in particular the third and / or the fifth release criterion. Specifically, the provision of the third diagnostic signal DS3 triggers the jump to the start step SF.

[0046] In a diagnostic process start step SD of diagnostic process D, the system waits for the diagnostic process start signal DPS to be available. Further steps of diagnostic process D are executed as soon as the presence of the diagnostic process start signal DPS is detected in diagnostic process start step SD. For further steps of diagnostic procedure V or diagnostic process D, the release time is treated as the start time of diagnostic procedure V or diagnostic process D. At the start time, a start exhaust gas temperature is detected using the exhaust gas temperature sensor, and a corresponding start exhaust gas temperature value T1 is provided (step ST1). It may be possible to determine in query A4 whether the other release bits relevant for the release state, bit0, bit1, bit2, bit3, are present together or separately.simultaneously have the value 1 and then, simultaneously with the assignment of the value 1 to the enable bit bit4, step ST1 is executed and the start exhaust gas temperature value T1 is provided.

[0047] Following the diagnostic process start step SD, a loop query L1 continuously monitors whether the cold start heating element control module is operating in cold start heating mode from the start time until a diagnostic point in time where one of the diagnostic signals DS1 or DS2 is provided. As soon as this is no longer the case, the third diagnostic signal DS3 is provided, and the process jumps to the release process start step SF. However, as long as the cold start heating element control module is operating in cold start heating mode, in step SD1 of the diagnostic process D, an exhaust gas temperature difference value T21 is calculated from the start exhaust gas temperature value T1 and an exhaust gas temperature value T2, using T21 = T2 - T1. The exhaust gas temperature value T2 characterizes the current exhaust gas temperature at the temperature measuring point after the start time.

[0048] A loop query L2 of the diagnostic process D continuously monitors whether the exhaust gas temperature difference value T21 is less than a predefined limit value GT. This limit value is determined or specified in step SD2 based on the initial exhaust gas temperature value T1. For example, the limit value GT is read from a characteristic curve or map over the initial exhaust gas temperature or calculated using a function. If and as often as the exhaust gas temperature difference value T21 is less than a predefined limit value GT, the process jumps to step SD1. The point in time after the start time at which the exhaust gas temperature difference value T21 is equal to or greater than a predefined or predefinable limit value GT is the diagnostic point. This means that from the start time onwards, the exhaust gas temperature value T21 is used to determine the limit value GT.The exhaust gas temperature difference value T21 is determined as long as the cold start heating element control module is operating in cold start heating mode, until the exhaust gas temperature difference value T21 is equal to or greater than the limit exhaust gas temperature difference value GT for the first time since the start time. The start exhaust gas temperature and the current exhaust gas temperature are each recorded by an exhaust gas temperature sensor.

[0049] Furthermore, in diagnostic process D, an exhaust gas mass value MA is determined in step SD3. This value characterizes the mass of exhaust gas emitted from the internal combustion engine between the start time and the diagnostic time. In comparison step SD4, the exhaust gas mass value MA is compared with a limit exhaust gas mass value GM, which is either predefined for diagnostic process D or determined during diagnostic process D. Based on the comparison result, the first diagnostic signal DS1 or the second diagnostic signal DS2 is output. For this purpose, an exhaust gas mass flow signal MSS, which characterizes the exhaust gas mass flow rate, is used (see Fig. 2d) is recorded and integrated over time between the start time and the diagnostic time, resulting in the exhaust gas mass. In this case, the exhaust gas mass flow signal MSS recorded in step SD3 is low-pass filtered in step SD5 and fed to a further loop query L3 of the diagnostic process D. The loop query L3 continuously monitors whether the current exhaust gas mass flow, recorded based on the low-pass filtered exhaust gas mass flow signal TMSS, is less than a predefined limit exhaust gas mass flow. In other words, it monitors whether the exhaust gas mass flow signal TMSS is less than a limit exhaust gas mass flow value GMSS. As soon as this is no longer the case, the third diagnostic signal DS3 is provided (see Fig. 2d: ResetMf_Diag) and jumped to the release process start step SF. However, as long as the current exhaust gas mass flow is less than the limit exhaust gas mass flow, the exhaust gas mass flow detected based on the exhaust gas mass flow signal MSS is integrated over time between the start time and the diagnostic time, resulting in the exhaust gas mass value MA.

[0050] In step SD6 of the diagnostic process D, the limit exhaust mass value GM is determined based on the low-pass filtered exhaust mass flow signal TMSS and the starting exhaust temperature value T1. For example, the limit exhaust mass value GM is read from a characteristic curve or map over the starting exhaust temperature and / or over the low-pass filtered exhaust mass flow signal TMSS, or calculated using a function. The limit exhaust mass value GM and the exhaust mass value MA are then passed to the comparison step SD4. In comparison step SD4, that is, at the diagnostic point – i.e., at the point in time when, after the start time, the exhaust temperature difference value T21 is equal to or greater than a predefined or predefinable limit exhaust temperature difference value GT – the limit exhaust mass value GM and the exhaust mass value MA are compared.If this comparison detects that the exhaust gas energy value, in this case the exhaust gas mass value MA, is equal to or greater than a predefined limit exhaust gas energy value, in this case the limit exhaust gas mass value GM, the first diagnostic signal DS1 is provided, which characterizes a correct integration state of the emission element. Conversely, if the comparison, or comparison step SD4, detects that the exhaust gas energy value / exhaust gas mass value MA is less than the predefined limit exhaust gas energy value / limit exhaust gas mass value GM, the second diagnostic signal DS2 is provided, which characterizes an incorrect integration state of the emission element.

[0051] Based on the first diagnostic signal DS1, a user of the exhaust system, for example, a user / driver of a motor vehicle equipped with an internal combustion engine, receives an initial notification in step SD7 of diagnostic process D, informing the user about the correct integration status of the emission element. If the second diagnostic signal DS2 is / was issued, the user / driver receives a second notification informing them about the incorrect integration status of the emission element. The provision of the second diagnostic signal DS2 will result in the targeted prevention of unrestricted operation of the internal combustion engine and / or the unrestricted operation of a motor vehicle equipped with an internal combustion engine by means of one or more sanctions.

[0052] The diagnostic signal DS1, DS2 is stored in a diagnostic memory upon its provision and retained in the diagnostic memory during a subsequent run of the diagnostic process, specifically until the next determination or provision of the (next) first or second diagnostic signal. Furthermore, in this example, the unrestricted operation of the internal combustion engine and / or the motor vehicle is specifically prevented as long as the second diagnostic signal DS2 is stored in the diagnostic memory. The second diagnostic signal DS2 stored in the diagnostic memory can be provided as the third diagnostic signal DS3 or together with the third diagnostic signal DS3. Moreover, the second diagnostic signal DS2 stored in the diagnostic memory can only be deleted by providing the first diagnostic signal DS1 through another complete run of the diagnostic process D or diagnostic procedure V.In response to the detection of the first diagnostic signal DS1, any active sanction measures may be deactivated, thereby reactivating the internal combustion engine and / or the motor vehicle.

[0053] Fig. Figure 2 shows a control model, generated using modeling software for physical systems, in this case Matlab Simulink, to illustrate a possible design of the diagnostic procedure. Where appropriate, elements in the above have been referred to Fig. 2.

[0054] The diagnostic process D, the diagnostic procedure V, the exhaust system, the internal combustion engine and the motor vehicle each demonstrate a way in which the task explained at the beginning, namely to create a particularly simple and reliable way to check an exhaust aftertreatment element for its correct integration into an exhaust system, is solved. Reference symbol list A0 query A1 query A2 query A3 query A4 query AL evaluation logic AM evaluation module bit0 Release bit_0 bit1 Release bit_1 bit2 Release bit_2 bit3 Release bit_3 bit4 Release bit_4 CW Codeword The diagnostic process DFS diagnostic release signal DPS diagnostic process start signal DS1 first diagnostic signal DS2 second diagnostic signal DS3 third diagnostic signal DTI1 outflow-side initial temperature difference value DTI2 inflow-side initial temperature difference value F Release process FPS release process start signal GM exhaust gas mass limit GMSS limit exhaust gas mass flow value GT limit exhaust gas temperature difference value GTI1 outflow-side initial maximum temperature difference value GTI2 inflow-side initial maximum temperature difference value L1 loop query L2 loop query L3 loop query MA exhaust gas mass value MSS exhaust mass flow signal SD diagnostic process start step SD1 Diagnostic Process Step SD2 Diagnostic Process Step SD3 Diagnostic Process Step SD4 Diagnostic Process Step / Comparison Step SD5 Diagnostic Process Step SD6 Diagnostic Process Step SD7 Diagnostic Process Step SD8 Diagnostic Process Step SF Release Process Start Step ST1 Step to provide the starting exhaust gas temperature value T1 Starting exhaust gas temperature value T2 exhaust gas temperature value T21 Exhaust gas temperature difference value TI1 initial exhaust gas temperature value on the outlet side TI2 inlet-side initial exhaust gas temperature value TM Engine temperature value TM1 maximum engine temperature value TM2 minimum engine temperature value TMSS low-pass filtered exhaust mass flow signal TU ambient temperature value V Diagnostic procedures

Claims

[1] Diagnostic process (D) for checking whether an emission element is correctly integrated into its emission element installation location of an exhaust system coupled to an internal combustion engine, wherein - an exhaust gas mass value (MA) is determined, which characterizes the exhaust gas mass emitted from the internal combustion engine between a start time and a diagnostic time, - an exhaust gas temperature difference value (T21) is calculated from - a start exhaust gas temperature value (T1), which characterizes a start exhaust gas temperature recorded at a temperature measuring point downstream of the emission element installation location at the time of start by means of an exhaust gas temperature sensor, and - an exhaust gas temperature value (T2) that characterizes an exhaust gas temperature recorded at the temperature measuring point by means of the exhaust gas temperature sensor after the start time, wherein the diagnostic time is as soon as the exhaust gas temperature difference value (T21) is equal to or greater than a specified limit exhaust gas temperature difference value (GT), - is determined at the time of diagnosis, - that the exhaust gas mass value (MA) is equal to or greater than a specified limit exhaust gas mass value (GM), whereupon at or after the time of diagnosis a first diagnostic signal (DS1) is provided which characterizes a correct integration state of the emission element, or - that the exhaust mass value (MA) is smaller than the specified limit exhaust mass value (GM), whereupon a second diagnostic signal (DS2) is provided at or after the time of diagnosis, which characterizes an incorrect integration state of the emission element. [2] Diagnostic process (D) according to claim 1, characterized by , that the limit exhaust mass value (GM) is specified based on the starting exhaust temperature value (T1). [3] Diagnostic process (D) according to claim 1 or 2, characterized by , that the exhaust mass value (MA) is determined by integrating an exhaust mass flow signal (MSS) characterizing an exhaust mass flow over time between the start time and the diagnosis time. [4] Diagnostic process (D) according to claim 3, characterized by , that the limit exhaust mass value (GM) is specified based on the exhaust mass value (MA). [5] Diagnostic process (D) according to claim 4, characterized by , that the exhaust gas mass flow signal (MSS) is low-pass filtered to specify the limit exhaust gas mass value (GM), and the limit exhaust gas mass value (GM) is specified based on the low-pass filtered exhaust gas mass flow signal (TMSS). [6] Diagnostic process (D) according to any of the preceding claims, characterized by, that an exhaust mass flow signal (MSS) characterizing the exhaust mass flow is detected, and the diagnostic process (D) continues, namely, - as long as the exhaust mass flow signal (MSS) characterizes an exhaust mass flow that is less than a specified limit exhaust mass flow, by integrating the detected exhaust mass flow signal (MSS) over time between the start time and the diagnostic time, resulting in the exhaust mass value (MA), and specifying the limit exhaust mass value (GM) based on the exhaust mass value (MA), or, - if the exhaust mass flow signal (MSS) characterizes an exhaust mass flow equal to or greater than the specified limit exhaust mass flow, by providing a third diagnostic signal (DS3) that characterizes an incomplete diagnostic process (D), in particular triggering its restart. [7] Diagnostic process (D) according to any of the preceding claims, characterized by, that the second diagnostic signal (DS2) is stored in a diagnostic memory due to its provision, and, as long as the second diagnostic signal (DS2) is stored in the diagnostic memory, unrestricted operation of the internal combustion engine is specifically prevented. [8] Diagnostic method (V) for checking whether an emission element is correctly integrated into its emission element installation location of an exhaust system coupled with an internal combustion engine, wherein the diagnostic method (V) comprises a release process (F) in which a predetermined release state of the exhaust system and / or the internal combustion engine is determined, and the diagnostic process (D) designed according to one of claims 1 to 7 is started as a reaction to the presence of the release state. [9] Diagnostic method (V) according to claim 8, characterized bythat the release state has one or two or more release criteria that must be met for the release state to exist, namely, - a first release criterion, which is fulfilled as soon as and as long as an outflow-side initial temperature difference value (DTI1), which is calculated from an initial exhaust gas temperature value (TI1) that characterizes an initial exhaust gas temperature prevailing downstream of the emission element installation location, and an ambient temperature value (TU) that characterizes the ambient temperature, is equal to or less than a specified outflow-side maximum initial temperature difference (GTI1), - a second release criterion, which is met as soon as and as long as an inlet-side initial temperature difference value (DTI2), calculated from an initial exhaust gas temperature value (TI2) that characterizes an initial exhaust gas temperature modeled upstream of the emission element installation location, and the ambient temperature value (TU), is equal to or less than a specified inlet-side maximum initial temperature difference value (GTI2), - a third release criterion, which is met as soon as and as long as a cold start heating medium control module is operated to control a cold start heating medium in a cold start heating mode for rapid heating of the exhaust system, - a fourth release criterion, which is fulfilled as soon as and as long as an engine temperature value (TM) characterizing the engine temperature of the internal combustion engine is within a specified or predefinable engine temperature value range, - a fifth release criterion, which is met as soon as and as long as the internal combustion engine is operated in a start-up mode to activate the internal combustion engine. [10] Diagnostic method (V) according to claim 8 or 9, characterized by , that a third diagnostic signal (DS3) is provided which characterizes an incomplete diagnostic process (D) once it is detected that the cold start heating control module has disabled or deactivated the cold start heating mode between the start time and the diagnostic time. [11] Exhaust system for an internal combustion engine, comprising: - an exhaust gas channel connectable to a combustion chamber arrangement of the internal combustion engine with an emission element installation location for an emission element which, when correctly seated in the emission element installation location, is fluidically integrated into the exhaust gas channel, - a control unit configured to perform the diagnostic process (D) designed according to any one of claims 1 to 7 or the diagnostic method (V) designed according to any one of claims 8 to 10. [12] Exhaust system according to claim 11, characterized by , that of their exhaust gas temperature sensors integrated into the exhaust duct exactly one is coupled or can be coupled to the control unit, and that this exhaust gas temperature sensor is located downstream of the emission element installation location. [13] Internal combustion engine with the exhaust system designed according to claim 11 or 12. [14] Motor vehicle, each with the exhaust system designed according to claim 11 or 12 or with the internal combustion engine designed according to claim 13.

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