Method for diagnosing the effectiveness of an emission control measure on a catalyst assembly of a motor vehicle and motor vehicle

Abstract

Method for diagnosing the effectiveness of an emission control measure on a catalyst assembly (2) of a motor vehicle (1), comprising the steps: - Monitoring (S21) at least one driving cycle of the motor vehicle (1) and - Determine (S22) whether the effectiveness of the emission control measure meets a specified minimum effectiveness in at least one monitored driving cycle, characterized by - Determine whether the effectiveness of the emission control measure meets the specified minimum effectiveness, in response to the completion of at least one monitored driving cycle, - Determining a property of at least one monitored and completed driving cycle, wherein the property can only be determined after completion of the monitored driving cycle (S33), and - Determine that the effectiveness of the emission control measure fails to meet the specified minimum effectiveness in response to the property falling below an assigned minimum value (S34, S44), - wherein the property of the at least one monitored and completed driving cycle includes a quantity of exhaust mass produced between an engine-ON event and an engine-OFF event of the motor vehicle (1) in the monitored and completed driving cycle.

Description

[0001] The invention relates to a method for diagnosing the effectiveness of an emission control measure on a catalytic converter assembly of a motor vehicle, comprising the steps of monitoring at least one driving cycle of the motor vehicle and determining whether the effectiveness of the emission control measure in the at least one monitored driving cycle meets a predetermined minimum effectiveness. The invention further relates to a motor vehicle comprising a catalytic converter assembly and a control unit.

[0002] From DE 101 60 704 A1, a method for operating exhaust gas purification devices is known. The method provides for measuring one or more exhaust gas components downstream of at least a part of the exhaust gas purification device, comparing the measured values ​​with corresponding target values, and varying the operating temperature of the exhaust gas purification device depending on the comparison result.

[0003] German patent DE 198 43 859 A1 discloses a method for improving exhaust gas quality in combustion processes with an exhaust gas catalyst when sulfur content is reduced. The catalyst's oxygen storage capacity is determined and compared to a threshold value. If the oxygen storage capacity falls below the threshold value, the exhaust gas temperature can be increased.

[0004] German patent application DE 10 2017 211 710 A1 discloses and describes a method for determining the current sulfur loading of a nitrogen oxide storage catalyst (NOC). The sulfur loading is determined by relating it to the oxygen storage capacity of the NOC. For example, a model can be used to determine the sulfur uptake from the sulfur content of the combusted fuel based on an open-loop control system.

[0005] DE 10 2006 038 367 A1 teaches a catalyst arrangement that produces an NO x-storage catalyst. The catalyst arrangement also includes an H2S storage catalyst, which is suitable for storing hydrogen sulfide under a rich or stoichiometric exhaust gas atmosphere with lambda ≤ 1 and releasing it under a lean exhaust gas atmosphere with lambda > 1.

[0006] From DE 10 2007 052 ​​360 A1, a method for operating a facility is known in which, if a fault occurs in the facility, at least one measure is taken to correct the fault during operation. At least one fault log is provided if the fault still exists after the at least one measure, and the at least one fault log is omitted if the fault has been corrected after the at least one measure.

[0007] DE 10 2017 215 247 A1 teaches a method for operating a motor vehicle with a drive unit, in particular a combustion engine. According to the aforementioned document, at least one characteristic parameter relating to the quality of a fuel located in a fuel tank of the motor vehicle and intended for operating the drive unit is analyzed and stored in a storage device for later use.

[0008] From DE 100 54 005 A1 a method for operating an exhaust gas purification system with nitrogen oxide storage for cleaning a nitrogen oxide-containing, sulfur-contaminated exhaust gas of a combustion device is known, in which desulfurization phases are carried out from time to time to release sulfur stored in the nitrogen oxide storage.

[0009] DE 10 2012 203 605 A1 discloses a method and a system for controlling a device for monitoring the efficiency of the nitrogen oxide (NOx) conversion of the type used in an engine exhaust system.

[0010] DE 10 2018 203 086 A1 discloses a method and an arrangement for regenerating an LNT catalyst arranged in an exhaust stream of an internal combustion engine, a control unit for controlling the regeneration of an LNT catalyst arranged in an exhaust stream of an internal combustion engine, and a motor vehicle.

[0011] It is an object of the invention to provide a method of the type mentioned at the outset for diagnosing the effectiveness of an emission control measure on a catalyst assembly of a motor vehicle, which is improved compared to the prior art.

[0012] The foregoing problem is solved by a method for diagnosing the effectiveness of an emission control measure on a catalytic converter assembly of a motor vehicle, comprising the features of independent claim 1, and by a motor vehicle comprising the features of independent claim 9. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the motor vehicle according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes, or can make, reciprocal references.

[0013] According to the invention, the method comprises determining whether the effectiveness of the emission control measure meets the specified minimum effectiveness in response to the completion of at least one monitored driving cycle.

[0014] The advantage of the solution according to the invention is that, based on information about the driving cycle that is only available after the entire driving cycle has been completed, it is possible to determine whether the minimum effectiveness has been met. This creates new possibilities for determining whether the effectiveness of the emission control measure meets the specified minimum effectiveness without having to perform this determination during the monitored driving cycle. The method can therefore be simpler, more reliable, and more cost-effective compared to the prior art. Thus, the method is an improvement over the prior art.

[0015] Advantageous embodiments of the invention are part of the dependent claims and are described in the description.

[0016] The driving cycle can begin with an engine-ON event and end with an engine-OFF event. The engine-ON event can be triggered, with the vehicle's engine off, by the driver starting the engine, in particular by turning an ignition key, pressing an accelerator pedal, or pressing a start button, to begin a driving cycle. The engine-OFF event can be triggered, with the engine running, by the driver stopping the engine, in particular by turning the ignition key or pressing a start button, to end a driving cycle. It is preferred that intermediate stop events, such as the brief shutdown of the engine at a traffic light as part of a start-stop system, are not considered engine-OFF events. Thus, an intermediate stop event can be detected if a start-stop system has taken control of the vehicle's engine.The intermediate stop event can also be detected in embodiments if the time period between an engine-off event and a subsequent engine-on event does not exceed a few minutes, such as 2, 3, or 5 minutes. The driving cycle thus preferably begins with an engine-on event and ends with an engine-off event, after which no further engine-on event occurs for more than 5 minutes. The engine is preferably an internal combustion engine, which is particularly preferably operable with diesel or gasoline as fuel.

[0017] The required minimum effectiveness of the emission control measure may be defined by regulatory requirements, such as a maximum duration of the measure. In some embodiments, the emission control measure involves the regeneration of a catalyst assembly whose effectiveness has been reduced, for example, by sulfur deposits.

[0018] In some embodiments, all or at least some of the process steps are performed by a control unit within the vehicle. This can have the advantage that the vehicle itself can perform the diagnostics using its control unit, eliminating the need for an external test bench. The control unit can be located in an interior space of the vehicle, enclosed by the vehicle's body. However, some embodiments provide for all or at least some of the process steps to be performed by a computer system on a test bench, where the effectiveness of the vehicle's catalytic converter assembly is tested. This allows for diagnostics to be performed, for example, in workshops, without requiring a dedicated control unit in the vehicle.

[0019] Some embodiments of the method include determining a property of at least one monitored and completed driving cycle, where the property can only be determined after the monitored driving cycle has ended, and determining that the effectiveness of the emission control measure fails to meet the specified minimum effectiveness because the property falls below an assigned minimum value. Some properties of driving cycles are subject to fluctuations during the driving cycle or can only be definitively determined after the end of the driving cycle. If such properties are determined for the entire driving cycle only after its completion, particularly by summing, averaging, or other arithmetic processes of their respective values ​​over time, the method proposed in this document may be more reliable than conventional methods.The assigned minimum value can in particular be a quantity of substance produced that is measured as an accumulation during the driving cycle, such as an exhaust mass produced by the engine of the motor vehicle during the monitored and completed driving cycle.

[0020] Some embodiments include generating an error message in response to the determination that the emission control measure is failing to meet the specified minimum effectiveness. This error message can then be stored in an error memory and / or used to trigger a display on the vehicle's dashboard, such as an error message or warning light. In this way, the method can not only determine the insufficient effectiveness but also store and / or display it to the driver. The error message is preferably generated after the completed driving cycle and before the immediately following one to ensure a direct temporal connection with the completed driving cycle. The error message can be an electrical signal that activates the warning light or an error memory.

[0021] In embodiments, the method may include monitoring a plurality of consecutive driving cycles and generating an error notification in response to the property falling below the assigned minimum value during a minimum number of consecutive monitored and completed driving cycles. This minimum number of consecutive driving cycles may be more than three, in particular four, six, eight, ten, fifteen, or more. This allows individual or a few driving cycles in which the property falls below the minimum value to be identified as outliers, thus preventing unnecessary error notifications from being generated for such outliers.

[0022] In embodiments, the method can include monitoring a plurality of consecutive driving cycles and generating a suspected fault notification in response to the fact that, for a successive number of suspected faults within the plurality of consecutive monitored and completed driving cycles that is less than the minimum number, the characteristic falls below the assigned minimum value. In embodiments, the number of suspected faults can comprise two or, preferably, three consecutive driving cycles. Preferably, the counter of completed driving cycles in which the minimum value is undershot is reset if, after a number of consecutive driving cycles in which the minimum value is undershot, a driving cycle occurs in which the minimum value is exceeded, and provided that the number of suspected faults has not yet been reached. This has the advantage that only one suspected fault notification is required.Later, an error message will be generated if the minimum value is actually undershot during a large number of consecutive driving cycles.

[0023] Specific embodiments involve setting an error bit in the vehicle's fault memory in response to the generation of a fault notification. Such fault memories are well-known and can be easily read in workshops or with commercially available equipment to detect any malfunctions of the emission control system. Setting the error bit can also help meet regulatory requirements regarding the diagnosis of the emission control system's effectiveness, as authorities increasingly require that the specified minimum effectiveness of the emission control system not only be ensured but also documented if it is not met. Some embodiments involve setting a suspected fault bit in the vehicle's fault memory in response to the generation of the suspected fault notification.Such a suspected fault bit can be advantageous in the workshop for recognizing that while no fault is currently present, a fault is likely to occur in the future. The fault memory can therefore contain both a suspected fault bit and a fault bit. The suspected fault bit can be set from 0 to 1 by the suspected fault notification. The fault bit can also be set from 0 to 1 by the fault notification.

[0024] The procedure may stipulate that the characteristic of at least one monitored and completed driving cycle includes a time interval between the engine start-up event and the engine stop-run event of the motor vehicle within the monitored and completed driving cycle. For some engines, driving cycle models are known for which it is ensured that the minimum effectiveness is exceeded within the driving cycle. If the interval falls below the minimum value, which is a minimum duration across all driving cycle models for which the minimum effectiveness is ensured, this can be used as an indication that the minimum effectiveness was not met in the monitored and completed driving cycle. In other words, the minimum value can be a minimum interval for which the motor vehicle's engine must be switched on in the driving cycle to achieve a minimum effectiveness of the emission control measure on the catalyst assembly within that driving cycle.The system preferably determines whether the driving cycle has exceeded the minimum required for regeneration. In some embodiments, the driving cycle's duration can be determined by a timing function of the control unit.

[0025] The procedure may stipulate that the characteristic of at least one monitored and completed driving cycle includes a quantity of substance produced between the engine start-up and engine stop events of the motor vehicle within that monitored and completed driving cycle. For some engines, driving cycle models are known for which it is ensured that the minimum effectiveness is exceeded within the driving cycle. If the quantity of substance produced falls below the minimum value, which is, for example, a quantity of substance from all driving cycle models for which the minimum effectiveness is ensured, this can be used as an indication that the minimum effectiveness cannot be assessed in the monitored and completed driving cycle. In other words, the minimum value may be a quantity of substance that the motor vehicle's engine must have produced or processed within the driving cycle to achieve a minimum effectiveness of the emission control measure within that driving cycle.

[0026] In some embodiments, the feature of at least one monitored and completed driving cycle includes a quantity of exhaust gas mass generated between the engine start-up and engine stop events of the vehicle within the monitored and completed driving cycle. The quantity of substance generated, as described above, is therefore preferably the generated exhaust gas mass. For some engines, generated exhaust gas masses are known for driving cycles for which it is ensured that the minimum efficiency in the driving cycle is exceeded. The generated exhaust gas masses are sufficiently large for these driving cycles to heat the catalyst assembly to such an extent that the minimum efficiency of the emission control measure is achieved.If the exhaust mass produced in the monitored and completed driving cycle falls below the minimum value, which is the minimum exhaust mass across all driving cycle models for which minimum effectiveness is ensured, this can be used as an indication that the minimum effectiveness of the emission control measure cannot be assessed in that monitored and completed driving cycle. In other words, the minimum value can be the minimum exhaust mass that the vehicle's engine must have produced in the monitored and completed driving cycle to achieve a minimum effectiveness of the emission control measure. The procedure may include determining the exhaust mass produced in the monitored and completed driving cycle. The total exhaust mass produced can only be determined after the driving cycle has been completed.The mass of exhaust gas produced can be easily determined for each driving cycle using sensors installed in the vehicle, in particular by summing the mass of exhaust gas produced over time in the monitored driving cycle.

[0027] Some embodiments involve increasing the temperature of the catalyst assembly in a subsequent driving cycle following the monitored and completed driving cycle by means of an auxiliary heating measure in response to the finding that the effectiveness of the emission control measure fails to meet the predetermined minimum effectiveness in the monitored and completed driving cycle. Preferably, the subsequent driving cycle is one immediately following the monitored and completed driving cycle. In some embodiments, the auxiliary heating measure may be ignition-angle heating. Other embodiments provide for the implementation of lambda-split operation, which may include exothermic heating of the catalyst assembly.

[0028] In particular, if a failure to meet the minimum effectiveness threshold is repeatedly detected, the auxiliary heating measure can influence a subsequent driving cycle in such a way that the probability of exceeding the minimum effectiveness threshold in the following driving cycle increases. The auxiliary heating measure can be limited to the following driving cycle or can be implemented for a multitude of consecutive future driving cycles. Preferably, the auxiliary heating measure is terminated as soon as the emission control measure is completed or a limit of 10 consecutive future driving cycles has elapsed without generating a further fault notification. This limit can be ten, fifteen, or twenty consecutive future driving cycles in various embodiments. The auxiliary heating measure can be implemented instead of setting the fault bit, thus preventing unnecessary workshop visits.

[0029] Implementations of the method stipulate that the emission control measure to be monitored is sulfur regeneration of the catalyst assembly. Sulfur regeneration may not be emission-neutral. Therefore, legislators (e.g., CARB in the USA) require that continuous regeneration be diagnosed and reported. Often, the vehicle lacks the necessary sensors to directly determine the desulfurization effectiveness from measurement data during the driving cycle. Therefore, it can be advantageous to wait until the driving cycle is complete and then, for example, as proposed in this document, to deduce from the exhaust gas mass generated during the monitored and completed driving cycle whether the minimum effectiveness of the emission control measure has been achieved.In general, however, the procedure can be used for any effectiveness of emission measures where, for example, it is impossible or costly to evaluate measurement data from an ongoing driving cycle in order to determine whether the emission measure meets the specified minimum effectiveness.

[0030] Optionally, instead of setting an error bit, or in addition to doing so, the regeneration intensity can be proactively increased in some embodiments, particularly by additionally heating the catalyst assembly. These embodiments provide for an evaluation at the end of the monitored driving cycle, comprising the following steps: - Determine if sulfur regeneration is active, - Determine whether a sulfur load modeled from the engine operating parameters is hardly reduced and - Determine whether the driving cycle has exceeded a minimum scope large enough to perform regeneration.

[0031] If each of these checks yields a positive result, a further step can be taken to determine that an error has occurred, and an error message can then be generated. This message can then be used as discussed above.

[0032] The invention, in its various embodiments, provides solutions for diagnosing continuous regeneration during desulfurization in a catalytic converter assembly of a motor vehicle. This diagnosis is based on information obtained from monitored and completed driving cycles of the vehicle. The diagnosis is preferably activated as soon as the sulfur regeneration is no longer emission-neutral. By evaluating the driving profile and the sulfur load, it can then be determined whether continuous regeneration is occurring and whether a fault memory entry needs to be generated. Optionally, instead of directly determining that a fault exists, the intensity of the regeneration for the next driving cycle can be increased, for example, by using auxiliary heating. This may prevent a fault memory entry (which, for example, is triggered after 5 driving cycles with unsuccessful regeneration).

[0033] Furthermore, it is an object of the invention to provide a motor vehicle of the type mentioned above that is improved compared to the prior art. This object is achieved by the motor vehicle according to claim 9.

[0034] The motor vehicle, whose control unit is equipped to carry out the procedure described above, creates new possibilities for determining whether the effectiveness of the emission control measure meets the specified minimum effectiveness, which may be simpler, more reliable or more cost-effective compared to the state of the art.

[0035] Preferably, the catalyst arrangement comprises a first catalyst unit and a second catalyst unit. The first catalyst unit can be a main catalyst. The first catalyst unit can be arranged in an exhaust duct downstream of a turbocharger of the motor vehicle. The second catalyst unit can be an underfloor catalyst. The second catalyst unit can be arranged in the exhaust duct downstream of the first catalyst. Embodiments may provide that the effectiveness of the emission control measure is a combined effectiveness on both the first and second catalyst units. In this case, the minimum effectiveness of the emission control measure preferably results from a combined minimum effectiveness on both the first and second catalyst units.

[0036] The motor vehicle is preferably a passenger car, truck, motorcycle, or bus. The control unit is preferably connected via wiring harnesses and / or wirelessly to a plurality of functional units of the motor vehicle in order to control them. The functional units can be one or more, including but not limited to, the engine, brakes, air conditioning system, lights, exhaust system, turbocharger, and catalytic converter assembly. The engine can be connected to the catalytic converter assembly via the motor vehicle's exhaust system.

[0037] Embodiments of the invention are explained in more detail with reference to the drawings and the following description. The drawings show: Fig. 1 an embodiment of a motor vehicle according to the invention; Fig. 2 a first embodiment of a method according to the invention; Fig. 3 a second embodiment of the method according to the invention; and Fig. 4 a third embodiment of the method according to the invention.

[0038] Fig. Figure 1 shows an embodiment of a motor vehicle 1 according to the invention. The motor vehicle 1 has a catalytic converter assembly 2. The motor vehicle 1 further has a control unit 3. The catalytic converter assembly 2 has a first catalytic converter 4 and a second catalytic converter 5. The motor vehicle 1 further has a turbocharger 6, an exhaust manifold 7, an engine 8, an exhaust system 9 and a fault memory 10.

[0039] The first catalyst 4 is located in the exhaust channel 7 downstream of the turbocharger 6. The second catalyst 5 is located in the exhaust channel 7 downstream of the first catalyst 4. The second catalyst 5 is an underfloor catalyst. The vehicle 1 has an internal combustion engine (engine 8) which is connected to the catalyst assembly 2 via the exhaust channel 7 in order to purify the exhaust gas from the internal combustion engine 8 of pollutants in the catalyst assembly 2. Purification here means reducing the amount of pollutants in the exhaust gas before it is released into the environment through the vehicle's exhaust system 9. The exhaust channel 7 thus connects the engine 8 to the exhaust system 9 via the catalyst assembly 2, so that the purified exhaust gas can be released into the environment. The fault memory 10 communicates electrically with the control unit 3 for data transmission and is integrated into the control unit 3 in this embodiment.

[0040] The control unit 3 of the motor vehicle 1 is configured to carry out a method according to the invention, wherein embodiments of the method are based on the Fig. 2, Fig. 3 and Fig. 4 are described.

[0041] With reference to Fig. Figure 2 describes a first embodiment of a method according to the invention. The method is a method for diagnosing the effectiveness of an emission control measure on a catalyst assembly 2 of the motor vehicle 1. Step S21 comprises monitoring at least one driving cycle of the motor vehicle 1. A subsequent step S22 comprises determining whether the effectiveness of the emission control measure meets a predetermined minimum effectiveness in the at least one monitored driving cycle. More precisely, in step S22, the determination of whether the effectiveness of the emission control measure meets the predetermined minimum effectiveness is carried out as a reaction to the completion of the at least one monitored driving cycle. This creates new possibilities for determining whether the effectiveness meets the predetermined minimum effectiveness without having to perform this determination during the monitored driving cycle.

[0042] Based on Fig. Figure 3 describes a second embodiment of the method according to the invention. Step S31 is identical to step S21. Step S32 is identical to step S22. A subsequent step S33 comprises determining a property of the at least one monitored and completed driving cycle, wherein the property can only be determined after completion of the monitored driving cycle. A subsequent step S34 comprises determining that the effectiveness of the emission control measure fails to meet the specified minimum effectiveness, as a reaction to the property falling below an assigned minimum value.

[0043] The characteristic of at least one monitored and completed driving cycle is present in the embodiment from Fig. 3. A time interval between an engine-ON event and an engine-OFF event of vehicle 1 in the monitored and completed driving cycle. The minimum value in this example is therefore a minimum duration of this time interval.

[0044] For example, the minimum duration here is 20 minutes, whereby the actual time elapsed between the engine-ON event and the engine-OFF event in the monitored and completed driving cycle, i.e., the duration of the driving cycle, is 15 minutes. In step S34, it is therefore determined that the effectiveness of the emission measure fails to meet the specified minimum effectiveness because the characteristic falls below the assigned minimum value.

[0045] A subsequent step S35 involves generating an error message in response to the determination that the emission control measure fails to meet the specified minimum effectiveness. A further step S36 involves setting an error bit in the fault memory 10 of the vehicle 1 in response to the generation of the error message. This allows the failure to meet the specified minimum effectiveness to be logged for a workshop.

[0046] A subsequent step S37 involves increasing the temperature of the catalyst assembly 2 in a driving cycle following the monitored and completed driving cycle by means of an auxiliary heating measure in response to the determination that the effectiveness of the emission control measure fails to meet the specified minimum effectiveness in the monitored and completed driving cycle. Ignition angle heating is used as an example here. For this purpose, the control unit 3 is instructed, in response to the setting of the fault bit after the next engine-ON event, i.e., at the beginning of the following driving cycle, to initiate the ignition angle heating in order to increase the operating temperature of the catalyst assembly 2 more than would be the case during normal operation due to the exhaust gas to be cleaned, which is generated by the engine 8.

[0047] Based on Fig. Figure 4 describes a third embodiment of the method according to the invention. Step S41 is identical to step S21. Step S42 is identical to step S22. A subsequent step S43 is identical to step S33. A subsequent step S44 is similar to step S34, except that, in this embodiment, unlike S34, the characteristic of at least one monitored and completed driving cycle includes a quantity of exhaust gas mass generated between the engine-ON event and the engine-OFF event of the motor vehicle 1 in the monitored and completed driving cycle. The generated exhaust gas mass is a specific embodiment of a generated quantity of substance. Here, the generated quantity of substance is produced by the engine 8 in the driving cycle. The generated exhaust gas mass is continuously measured by the control unit 3 during the driving cycle and, as soon as the driving cycle is completed, is finally determined by summation.Since it is known what exhaust gas mass is required to sufficiently heat the catalyst arrangement 2 in the driving cycle to meet the specified minimum efficiency, a shortfall in the amount of exhaust gas mass can serve as an indication that the specified minimum efficiency was not met in the monitored and completed driving cycle.

[0048] A subsequent step S45 involves monitoring a plurality of consecutive driving cycles. For example, this includes 15 consecutive driving cycles. A further step S46 involves generating an error notification in response to the determination that the effectiveness of the emission measure fails to meet the specified minimum effectiveness. The error notification is generated in response to the property falling below the assigned minimum value for a successive minimum number of the plurality of consecutive monitored and completed driving cycles. In this embodiment, the error notification is therefore not generated immediately upon the first instance of the minimum value being undershot for a driving cycle, but only when the successive minimum number of successive monitored and completed driving cycles falls below the assigned minimum value.The minimum number required here is 10 consecutive monitored and completed driving cycles.

[0049] For example, in the embodiment according to Fig. Section 4 determines that the first two consecutive monitored and completed driving cycles meet the specified minimum effectiveness because the exhaust mass exceeds the minimum value in each case. In the following 10 consecutive monitored and completed driving cycles, the exhaust mass falls below the minimum value in each case. Since this can no longer be interpreted as an outlier, but rather the minimum number of consecutive monitored and completed driving cycles has been reached, the fault notification is generated. In step S46, an error bit is therefore set again in the fault memory 10 of the vehicle 1 in response to the generation of the fault notification. Thus, as in the procedure according to Fig. 3, the failure to meet the minimum effectiveness is documented. Additionally, in step S46, a warning light is illuminated on the dashboard of vehicle 1 to inform the driver of vehicle 1 about the generated fault notification and to prompt them to visit a workshop.

[0050] The exemplary feature in all three embodiments of the method is that it is based on the Fig. 2, Fig. 3 and Fig. Figure 4 illustrates the effectiveness of the emission control measure, a sulfur regeneration of the catalyst assembly 2. The vehicle 1 does not have the necessary sensors to directly determine the sulfur regeneration from measurement data during the driving cycle. Therefore, it is advantageous to first wait until the driving cycle is complete in order to then, for example, calculate the sulfur regeneration from the elapsed time between the engine-ON event and the engine-OFF event, as shown in Figure 4. Fig. 3, or the mass of exhaust gas produced, as in Fig. 4. To deduce whether the minimum efficiency was achieved in the monitored and completed driving cycle. This is possible because the minimum scope of a driving cycle, or the amount of exhaust gas that must be generated, to achieve sufficient sulfur regeneration is known.

[0051] The invention is not limited to the embodiments described in detail above, but is defined by the accompanying independent claims. The embodiments of the invention, which are explained in the description or listed in the dependent claims, can be combined with one another to form new embodiments, provided that features of the embodiments do not expressly contradict each other. Individual steps from the described detailed embodiments can also be removed or added. The sequence of the described steps can also be modified, provided that the basic functionality of the method is maintained. Reference symbol list 1 motor vehicle 2 Catalyst arrangement 3 Control unit 4 first catalyst 5 second catalyst 6 turbochargers 7 Exhaust channel 8 engine 9 Exhaust system 10 Error memory S21, S22 procedural steps S31 - S37 Procedure steps S41 - S46 Procedure steps

Claims

[1] Method for diagnosing the effectiveness of an emission control measure on a catalyst assembly (2) of a motor vehicle (1), comprising the steps: - Monitoring (S21) at least one driving cycle of the motor vehicle (1) and - Determine (S22) whether the effectiveness of the emission control measure meets a specified minimum effectiveness in at least one monitored driving cycle, characterized by - Determine whether the effectiveness of the emission control measure meets the specified minimum effectiveness, in response to the completion of at least one monitored driving cycle, - Determining a property of at least one monitored and completed driving cycle, wherein the property can only be determined after completion of the monitored driving cycle (S33), and - Determine that the effectiveness of the emission control measure fails to meet the specified minimum effectiveness in response to the property falling below an assigned minimum value (S34, S44), - wherein the property of the at least one monitored and completed driving cycle includes a quantity of exhaust mass produced between an engine-ON event and an engine-OFF event of the motor vehicle (1) in the monitored and completed driving cycle. [2] Method according to claim 1, characterized by - Generating an error notification in response to the determination that the effectiveness of the emission control measure fails to meet the specified minimum effectiveness (S35). [3] Method according to claim 2, characterized by - Monitoring a large number of consecutive driving cycles (S45) and - Generating the error notification in response to the fact that the property falls below the assigned minimum value for a successive minimum number of the multitude of successive monitored and completed driving cycles (S46). [4] Method according to claim 2 or 3, characterized by - Setting an error bit in a fault memory (10) of the motor vehicle (1) in response to the generation of the fault notification (S36). [5] Method according to any one of claims 2 to 4, characterized by , that the characteristic of at least one monitored and completed driving cycle includes a time interval between an engine-ON event and an engine-OFF event of the motor vehicle (1) in the monitored and completed driving cycle. [6] Method according to any one of claims 1 to 5, characterized by - Increasing the temperature of the catalyst assembly (2) in a subsequent driving cycle following the monitored and completed driving cycle by means of an additional heating measure in response to the finding that the effectiveness of the emission control measure fails to meet the specified minimum effectiveness in the monitored and completed driving cycle (S37). [7] Method according to any of the foregoing claims, characterized by , that the emission measure is a sulfur regeneration of the catalyst assembly (2). [8] Motor vehicle (1) which has the following features: - a catalyst arrangement (2) and - a control unit (3), characterized by , that the control unit (3) is configured to carry out the method according to any one of claims 1 to 7.

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