Method, control device and computer program for determining a corrected gas fraction of a gas component in exhaust gas flowing through an exhaust tract of an internal combustion engine, as well as exhaust tract, internal combustion engine, vehicle and computer-readable medium.

Abstract

The present invention relates to a method, a control device, and a computer program for determining a corrected gas fraction of a gas component in exhaust gas flowing through an exhaust tract of an internal combustion engine, as well as an exhaust tract, an internal combustion engine, a vehicle, and a computer-readable medium. The internal combustion engine has a storage catalyst (20) and an exhaust gas sensor (22) arranged downstream of the exhaust catalyst (20).The method according to the invention comprises receiving an operating state signal that is representative of a cold operating state or a warm operating state of the storage catalyst, receiving at least one first exhaust gas signal from the exhaust gas sensor (22) if the received operating state signal indicates a cold operating state of the storage catalyst (20), determining a correction value based on the at least one received first exhaust gas signal, receiving at least one second exhaust gas signal from the exhaust gas sensor (22) if the received operating state signal indicates a warm operating state of the storage catalyst (20), and determining a corrected gas fraction of the gas component in the exhaust gas of the internal combustion engine (10) at least partially based on the at least one received second exhaust gas signal and the determined correction value.

Description

[0001] The present invention relates to a method, a control device and a computer program for determining a corrected nitrogen oxide content of a gas component in exhaust gas flowing through an exhaust tract of an internal combustion engine, in particular a diesel internal combustion engine, as well as an exhaust tract, an internal combustion engine, a vehicle and a computer-readable medium.

[0002] In internal combustion engines, especially diesel engines, it is known to use so-called SCR (selective catalytic reduction) catalysts, which are used to reduce nitrogen oxides in the exhaust gases of the internal combustion engine. The chemical reaction at the SCR catalyst is selective, meaning that the nitrogen oxides (NO, NO2) are preferentially reduced, while undesirable side reactions, such as the oxidation of sulfur dioxide to sulfur trioxide, are largely suppressed.

[0003] For the chemical reaction, urea is injected into the exhaust gas upstream of the SCR catalyst. This urea then decomposes, at least partially, into ammonia, which can react with the exhaust gas to form water and nitrogen within the SCR catalyst. To control the amount of urea injected, nitrogen oxide sensors, for example, are used to measure the respective levels in the exhaust tract of the internal combustion engine and then control the correct amount of urea to be injected.

[0004] Furthermore, it is known in internal combustion engines, especially diesel internal combustion engines, to use a catalyzed diesel particulate filter (SDPF) upstream of the SCR catalyst, which consists of a diesel particulate filter with an SCR coating.

[0005] In the prior art, for example in Deinhofer et al., “Analysis of the NOx storage behaviour during cold start of modern SCR flow-through substrates and SCR on-filter substrates”, Automotive and Engine Technology (2022), Springer Publishing, published online on December 23, 2021, it was found that modern storage catalysts, such as SCR catalysts or NOx storage catalysts, at least partially store certain gas components, such as nitrogen oxides, hydrocarbon compounds and oxygen, during their warm-up phase after a cold start of the internal combustion engine.

[0006] Furthermore, the disclosure by SCHMEISSER et al., Cold Start Effect Phenomena over Zeolite SCR Catalysts for Exhaust Gas Aftertreatment, SAE International J. Commer. Veh., Volume 6, Issue 1 (May 2023), published on August 4, 2013, is known.

[0007] Weiteren Stand der Technik bilden DE 10 2018 202 645 A1, DE 10 201,3 209 487 A1, DE 198 10 483 A1, DE 10 2012 205 464 A1, EP 1 365 234 B1, DE 198 10 483 A1, US 2023 / 0 112 942 A1, US 11 125 132 B2, US 8 769 929 B2, DE 10.2019 210 739 A1 und US 11 840 953 B2.

[0008] DE 10 2004 051 747 A1 relates to a method for operating an internal combustion engine in whose exhaust gas section a NOx storage catalyst and a NOx sensor are arranged downstream of the NOx storage catalyst, and to a device for carrying out the method, which exhibits high reliability through a correction capability of the NOx sensor signal provided by the NOx sensor. In an operating state of the NOx storage catalyst in which the NOx storage catalyst has no or only a low NOx storage capacity, a comparison is made between a measure of the NOx concentration upstream of the NOx storage catalyst and the NOx sensor signal provided by the NOx sensor arranged downstream of the NOx storage catalyst. The correction of the NOx sensor signal can be made depending on the comparison result.

[0009] It is an object of the present invention to provide a method and a control device with which the nitrogen oxide content in the exhaust gas can be determined individually for each vehicle and as accurately as possible.

[0010] This problem is solved by a method according to claim 1, a control device according to claim 9, a catalyst arrangement according to claim 9, a catalyst arrangement according to claim 11, an internal combustion engine according to claim 13, a computer program according to claim 14, and a computer-readable medium according to claim 15. Advantageous embodiments are specified in the dependent claims.

[0011] The present invention is essentially based on the idea of ​​utilizing the storage effect of storage catalysts, known from the prior art, before a predetermined storage temperature is reached, such that during this storage phase it can be assumed that the storage catalyst is at least temporarily storing the nitrogen oxides. Consequently, the exhaust gas flowing through the storage catalyst is, at least temporarily, essentially free of nitrogen oxides downstream of it. With a functioning exhaust gas sensor, it is expected that it will generate a signal corresponding to a nitrogen oxide content in the exhaust gas of essentially zero. However, if the signal generated by the exhaust gas sensor during the storage phase of the storage catalyst indicates a certain nitrogen oxide content, which can be positive or negative, this value can be used to correct the nitrogen oxide content in the exhaust gas determined by the exhaust gas sensor.

[0012] Consequently, according to a first aspect of the present invention, a method for determining a corrected nitrogen oxide content in exhaust gas flowing through an exhaust tract of an internal combustion engine is disclosed. The internal combustion engine has a storage catalyst configured to treat the exhaust gas and to store at least one gas component present in the exhaust gas, at least temporarily, and an exhaust gas sensor arranged downstream of the storage catalyst, which is configured to generate an exhaust gas signal that is representative of the nitrogen oxide content in the exhaust gas. The storage catalyst can be in a cold operating state, in which the temperature of the storage catalyst is lower than a predetermined storage temperature of the storage catalyst, or in a warm operating state.where the temperature of the storage catalyst is greater than or equal to the predetermined storage temperature of the storage catalyst. The method according to the invention comprises receiving an operating state signal that is representative of the cold operating state or hot operating state of the storage catalyst; receiving at least one first exhaust gas signal from the exhaust gas sensor when the received operating state signal indicates a cold operating state of the storage catalyst, wherein the exhaust gas downstream of the storage catalyst is essentially free of nitrogen oxides during the cold operating state, since the storage catalyst stores essentially all nitrogen oxides at least temporarily; determining a correction value based on the at least one received first exhaust gas signal; and receiving at least one second exhaust gas signal from the exhaust gas sensor that is representative of the nitrogen oxide content in the exhaust gas.if the received operating condition signal indicates a warm operating condition of the storage catalyst, and a determination of a corrected nitrogen oxide content in the exhaust gas of the internal combustion engine at least partially based on the at least one received second exhaust gas signal and the determined correction value.

[0013] According to a preferred embodiment of the inventive method, the determination of the correction value is based on the at least one received first exhaust gas signal and a predetermined expected value that is representative of an expected nitrogen oxide content in the exhaust gas while the storage catalyst is in the cold operating state.

[0014] The predetermined expected value is preferably zero, since - as already mentioned - the exhaust gas downstream of the storage catalyst is essentially free of nitrogen oxides during the cold operating condition, as the storage catalyst essentially stores all nitrogen oxides, at least temporarily.

[0015] In a further preferred embodiment, the method according to the invention also includes a determination that the amount of the determined correction value exceeds a predetermined nitrogen oxide threshold. The determination of the corrected nitrogen oxide content only takes place once it has been determined that the amount of the determined correction value exceeds the predetermined nitrogen oxide content threshold.

[0016] With such a preferred embodiment, a certain amount of signal noise from the exhaust gas sensor can be taken into account. In particular, such signal noise arises because the exhaust gas sensor is subject to signal drift over its lifetime and / or because certain molecules of the gas component nevertheless pass through the storage catalyst. Consequently, it can be advantageous to determine a corrected nitrogen oxide (NOx) content only when the magnitude of the determined correction value exceeds the predetermined NOx content threshold. In particular, the determined correction value can be positive or negative, which is why the magnitude of the determined correction value is compared with the predetermined NOx content threshold. Preferably, the predetermined NOx content threshold is approximately 5 ppm.

[0017] In an advantageous embodiment of the method according to the invention, if it has been determined that the calculated correction value exceeds the predetermined nitrogen oxide content threshold, the method further includes determining an adjustment value based on the calculated correction value and the predetermined nitrogen oxide content threshold. The determination of the corrected nitrogen oxide content is based at least partially on the calculated adjustment value.

[0018] Preferably, determining the adjustment value includes calculating the difference between the determined correction value and the predetermined nitrogen oxide content threshold.

[0019] With such an advantageous design, for example, the signal noise already mentioned above, such as part-to-part scattering, can be further taken into account, since not the entire correction value is used to correct the determined nitrogen oxide content, but this correction value is adjusted to account for, e.g., part-to-part scattering.

[0020] According to a further preferred embodiment, the method according to the invention also includes determining a time integral of the at least one received first exhaust gas signal for a predetermined time interval. The determination of the correction value is based at least partially on the determined time integral. Preferably, the predetermined time interval is approximately 5 seconds, approximately 10 seconds, or approximately 15 seconds.

[0021] In a further advantageous embodiment, the method according to the invention further comprises determining an average nitrogen oxide content value based on the at least one received first exhaust gas signal. The determination of the correction value is then based at least partially on the determined average nitrogen oxide content value. The average nitrogen oxide content value can preferably be determined based on the first exhaust gas signal received over a period of, for example, 5 to 15 seconds.

[0022] According to a further aspect of the present invention, a control device is disclosed which is configured to perform the steps of a method according to the invention.

[0023] Preferably, the control device according to the invention comprises a first control device section for performing the step of receiving the operating state signal, a second control device section for performing the step of receiving the at least one first exhaust gas signal, a third control device section for performing the step of determining a correction value, a fourth control device section for performing the step of receiving the at least one second exhaust gas signal, and a fifth control device section for performing the step of determining the corrected nitrogen oxide content in the exhaust gas.

[0024] According to a further aspect of the present invention, a catalyst arrangement for an internal combustion engine is disclosed, comprising a storage catalyst designed to treat the exhaust gas of the internal combustion engine and to store at least some nitrogen oxide present in the exhaust gas at least temporarily, an exhaust gas sensor arranged downstream of the storage catalyst designed to generate a signal representative of the nitrogen oxide content in the exhaust gas, and a control device according to the invention.

[0025] In a preferred embodiment of the catalyst arrangement according to the invention, the storage catalyst is a catalyst device with selective catalytic reduction, such as an SCR catalyst or a diesel particulate filter with SCR coating. It is further preferred that the exhaust gas sensor is a nitrogen oxide sensor configured to generate a nitrogen oxide signal that is representative of the nitrogen oxide content in the exhaust gas of the internal combustion engine.

[0026] Alternatively, the storage catalyst could be a NOx storage catalyst for diesel or hydrogen combustion engines, or a three-way catalyst for gasoline combustion engines with an oxygen storage effect. The exhaust gas sensor could be an oxygen sensor designed to generate an oxygen signal representative of the oxygen content in the combustion engine's exhaust gas.

[0027] According to a further aspect of the present invention, an internal combustion engine for a vehicle with a catalyst device according to the invention is disclosed.

[0028] According to a further aspect of the present invention, a computer program is disclosed comprising instructions which, when executed by a computing unit, cause the computing unit to execute a method according to the invention for determining a corrected nitrogen oxide content in an exhaust gas flowing through an exhaust tract of an internal combustion engine.

[0029] According to a further aspect of the present invention, a computer-readable medium is disclosed on which the computer program according to the invention is stored.

[0030] Further tasks and features of the present invention will become apparent to the person skilled in the art by carrying out the disclosed teaching and by looking at the accompanying drawings, in which: Fig. 1 shows a part of an exhaust tract of an internal combustion engine according to the invention, which has an exhaust gas sensor arranged downstream of a storage catalyst, and Fig. Figure 2 shows a flowchart of a method according to the invention for determining a corrected nitrogen oxide content in an exhaust gas flowing through an exhaust tract of an internal combustion engine.

[0031] Within the scope of this disclosure, the term "signal" describes raw data that is converted into a form suitable for transmission via the chosen transport medium. This can be done analogously or digitally, whereby the data is first sampled and converted into discrete (often binary-coded) values, which are then transmitted as current pulses or voltages of varying amplitudes via the medium. Furthermore, within the scope of this disclosure, signals can be transmitted and received continuously. For example, the transmission and reception of digital signals occur at intervals of a few milliseconds. The term "signal" is also intended to refer to a physical quantity that transmits information. A signal can take various forms, such as an electrical voltage, an electromagnetic wave, or a light pulse.It serves as a carrier of data, which is encoded by modulating the signal and then transmitted via various channels. These can be analog or digital signals. Analog signals vary continuously and can assume an infinite number of values ​​within a range. Digital signals consist of discrete values, often represented in binary states.

[0032] Within the scope of this disclosure, the term "storage temperature" of the storage catalyst describes a temperature threshold below which the storage catalyst has the ability to temporarily store gas component(s). If the temperature of the storage catalyst is below the storage temperature, it is, according to this disclosure, in a cold operating state. If the temperature of the storage catalyst is above the storage temperature, it is, according to this disclosure, in a hot operating state. The storage temperature is approximately 50 °C.

[0033] The Fig. Figure 1 schematically shows a section of an exhaust system 10 of an internal combustion engine (not shown in detail), which directs the exhaust gas of the internal combustion engine along the direction indicated by arrows 12 and 14. The internal combustion engine can be a gasoline or diesel engine, a hydrogen engine, or a gas engine (e.g., CNG). In the Fig. In the exemplary embodiment shown in Figure 1, the internal combustion engine is designed as a diesel internal combustion engine.

[0034] The exhaust system 10 includes a storage catalyst 20, which is designed to treat the exhaust gas and to store at least some nitrogen oxide present in the exhaust gas, at least temporarily. The storage catalyst 20 can be in a cold operating state, in which the temperature of the storage catalyst 20 is lower than a predetermined storage temperature of the storage catalyst 20, or in a warm operating state, in which the temperature of the storage catalyst 20 is higher than or equal to the predetermined storage temperature of the storage catalyst 20. In the Fig. In the exemplary embodiment shown in Figure 1, the storage catalyst 20 can be a catalyst with selective catalytic reduction, a so-called SCR catalyst, which is designed to carry out a chemical reaction so that the nitrogen oxides in the exhaust gas can be reduced. Alternatively, the storage catalyst 20 can be a NOx storage catalyst.

[0035] For the expert, it goes without saying that the one in the Fig. The exhaust system shown in Figure 1 can include 10 further exhaust components that are well known from the prior art, such as a urea injection device; which is designed to inject a predetermined quantity of urea at predetermined times. The injected urea is designed to be decomposed by the exhaust gas in such a way that at least some ammonia is produced, which can chemically react within the storage catalyst 20 and thus reduce the nitrogen oxides in the exhaust gas and can be at least partially stored in the storage catalyst 20.

[0036] Downstream of the storage catalyst 20, an exhaust gas sensor 22 is arranged, which is configured to generate an exhaust gas signal that is representative of the nitrogen oxide content in the exhaust gas of the internal combustion engine. According to the exemplary embodiment of the Fig. 1 a nitrogen oxide sensor 22 designed to generate an exhaust gas signal that is representative of the concentration (in [ppm] - “parts per million”) of nitrogen oxides in the exhaust gas.

[0037] Alternatively, the exhaust gas sensor 22 can be an oxygen sensor designed to generate an oxygen signal that is representative of the oxygen content in the exhaust gas of the internal combustion engine.

[0038] The exhaust system 10 further comprises a control device 60, which is connected to the exhaust gas sensors 22 via a suitable connecting line and is designed to control the exhaust system 10. The control device 60 can have several control device sections, such as a first control device section 62, a second control device section 64, a third control device section 66, a fourth control device section 68, and a fifth control device section 69, which are referred to with reference to the Fig. 2 will be discussed in more detail below.

[0039] The control device 60 can comprise a processor or arithmetic unit and a memory. Alternatively, the control device 60 can be the processor or arithmetic unit connected to the memory. The processor can be a central processing unit (CPU). The processor can also be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or another programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or the like. The general-purpose processor can be a microprocessor, or the processor can be any conventional processor or the like.

[0040] The memory includes, but is not limited to, Random Access Memory (RAM), Read-Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM), or Portable Read-Only Memory (e.g., CD-ROM). The memory is configured to store associated program instructions and data.

[0041] A method according to the invention for determining a corrected nitrogen oxide content in the exhaust gas is described below with reference to the Fig. 2 explains. An example of a method for determining a corrected nitrogen oxide content in the exhaust gas of the internal combustion engine is explained, whereby the method can also be carried out analogously for the gas content of other gas components, such as the carbon dioxide content and the oxygen content.

[0042] The procedure of Fig.Step 2 starts at step 200 and then proceeds to step 210, where the control device 60, in particular the first control device section 62, receives an operating state signal that is representative of the cold operating state or hot operating state of the storage catalyst 20. In particular, the storage catalyst 20 can be in a cold operating state, in which the temperature of the storage catalyst 20 is less than a predetermined storage temperature of the storage catalyst 20, or in a hot operating state, in which the temperature of the storage catalyst 20 is greater than or equal to a predetermined storage temperature of the storage catalyst 20.

[0043] For example, the operating state signal could be a temperature signal from a temperature sensor (not shown) designed to generate a temperature signal representative of the storage catalyst 20. Alternatively or additionally, the operating state signal could be generated using an operating parameter model of the internal combustion engine. Various operating parameters of the internal combustion engine could be used to estimate the temperature of the storage catalyst 20 using a model such as a temperature model or a thermal integral. For example, a predetermined time interval, such as between 20 and 30 seconds, could be defined, so that when this predetermined time interval expires, it can be assumed that the storage catalyst 20 has reached its storage temperature and is therefore in a warm operating state from that point onward.

[0044] In a subsequent step 220, the control device 60 checks whether the operating state signal received in step 210 is representative of a cold operating state or a warm operating state of the storage catalyst 20. If step 220 determines that the operating state signal received in step 210 is representative of a cold operating state of the storage catalyst 20, the method proceeds to step 225, in which the control device 60, in particular the second control device section 64, receives a first exhaust gas signal from the exhaust gas sensor 22, such as a first nitrogen oxide signal from the nitrogen oxide sensor 22. The method then returns to step 210.

[0045] Consequently, the process remains in the loop of steps 210, 220, and 225 until step 220 determines that the operating state signal received in step 210 is representative of a warm operating state of the storage catalyst 20. It should be noted that the first exhaust gas signal received in step 225 is either received only once or several times, i.e., for example, with each iteration of the loop of steps 210, 220, and 225. Alternatively, the first exhaust gas signal can be received for a predetermined period, such as 5 seconds, 10 seconds, or 15 seconds after a cold start of the internal combustion engine.

[0046] If, in step 220, it is determined that the operating condition signal received in step 210 is representative of a warm operating condition of the storage catalyst 20, the method proceeds to step 230, in which the control device 60, in particular the fourth control device section 68, receives a second exhaust gas signal from the exhaust gas sensor 22, such as a second nitrogen oxide signal from the nitrogen oxide sensor 22.

[0047] In a subsequent step 240, which in a further embodiment can be performed simultaneously with step 230, the control device 60, in particular the third control device section 66, determines a correction value based on the at least one first exhaust gas signal received in step 225. The determination of the correction value can be based either on a single first exhaust gas signal received in step 225 or on several received first exhaust gas signals. For example, in step 240, an average nitrogen oxide content value of all first exhaust gas signals received in step 225 can be determined, whereby determining an average value or an integral can help to at least partially eliminate any signal noise. Additionally or alternatively, a time integral of the at least one first exhaust gas signal received in step 225 can be determined for a predetermined time period.The determination of the correction value at step 240 is then based at least partially on the calculated time integral.

[0048] In a subsequent step 250, which is optional, the control device 60 checks whether the correction value determined in step 240 exceeds a predetermined nitrogen oxide (NOx) content threshold. If step 250 determines that the correction value determined in step 240 does not exceed the predetermined NOx content threshold, the procedure proceeds to step 270 and terminates.

[0049] However, if it is determined that the correction value determined in step 240 exceeds the predetermined nitrogen oxide (NOx) content threshold, such as 5 ppm, the method proceeds to step 260, in which the control device 60, in particular the fifth control device section 69, determines a corrected NOx content in the exhaust gas of the internal combustion engine. For example, the control device 60, in particular the fifth control device section 69, can subtract the correction value determined in step 240 from the NOx content determined based on the second exhaust gas signal received in step 230 in order to determine the corrected NOx content.

[0050] In an advantageous embodiment, step 260 may further comprise a step, namely the determination of an adjustment value based on the determined correction value and the predetermined nitrogen oxide (NOx) threshold. In such an advantageous embodiment, the determination of the corrected NOx content is based at least partially on the determined adjustment value. This means that not the entire correction value is used to correct the NOx content, but only the NOx content exceeding the predetermined NOx threshold. For example, if the predetermined NOx threshold is 5 ppm and the correction value determined in step 240 is 9 ppm, it may be preferable in such an advantageous embodiment for the NOx content indicated by the second exhaust signal to be corrected by only 4 ppm and not by the entire correction value of 9 ppm.Reducing the correction value by the predetermined nitrogen oxide content threshold can therefore take into account signal noise, such as nominal or part-to-part variation, of the exhaust gas sensor 22.

[0051] Furthermore, the procedure after step 260 may include a step in which the control device 60 sends a corrected nitrogen oxide content signal that is representative of the corrected nitrogen oxide content determined in step 260.

[0052] After step 260, the procedure ends at step 270.

[0053] With the present invention, the existence of a special operating state of the storage catalyst 20, in particular during the time immediately after a cold start of the internal combustion engine, can be used to calibrate the zero point of the exhaust gas sensor 22, since during the special operating state of the storage catalyst 20 it can be assumed that the exhaust gas at the position of the exhaust gas sensor 22, which is arranged downstream of the storage catalyst 20, is essentially free of nitrogen oxide.

Claims

[1] Method for determining a corrected nitrogen oxide content in exhaust gas flowing through an exhaust tract (10) of an internal combustion engine, wherein the internal combustion engine has a storage catalyst (20) configured to treat the exhaust gas and to store at least some nitrogen oxide present in the exhaust gas at least temporarily, and an exhaust gas sensor (22) arranged downstream of the storage catalyst (20) configured to generate an exhaust gas signal representative of the nitrogen oxide content in the exhaust gas, wherein the storage catalyst (20) can be in a cold operating state in which the temperature of the storage catalyst (20) is less than a predetermined storage temperature of the storage catalyst (20), or in a warm operating state in which the temperature of the storage catalyst (20) is greater than or equal to the predetermined storage temperature of the storage catalyst (20),wherein the storage temperature of the storage catalyst (20) describes a temperature threshold below which the storage catalyst (20) has the ability to temporarily store nitrogen oxides, wherein the method comprises: - Receiving an operating state signal that is representative of the cold operating state or warm operating state of the storage catalyst (20), - Receiving at least one initial exhaust gas signal from the exhaust gas sensor (22) when the received operating state signal indicates a cold operating state of the storage catalyst (20), wherein the exhaust gas downstream of the storage catalyst (20) is essentially free of nitrogen oxides during the cold operating state, since the storage catalyst (20) essentially stores all nitrogen oxides at least temporarily, - Determining a correction value based on at least one received initial exhaust gas signal, - Receiving at least one second exhaust gas signal from the exhaust gas sensor (22) when the received operating state signal indicates a warm operating state of the storage catalyst (20), and - Determining a corrected nitrogen oxide content in the exhaust gas of the internal combustion engine (10) at least partially based on the at least one received second exhaust gas signal and the determined correction value. [2] Method according to claim 1, wherein the determination of the correction value is based on the at least one received first exhaust gas signal and a predetermined expected value that is representative of the expected nitrogen oxide in the exhaust gas while the storage catalyst (20) is in the cold operating state. [3] Method according to any one of the preceding claims, further comprising: - Determine that an amount of the determined correction value exceeds a predetermined nitrogen oxide content threshold, whereby the determination of the corrected nitrogen oxide content only takes place when it has been determined that the determined amount of the determined correction value exceeds the predetermined nitrogen oxide content threshold. [4] The method of claim 3, wherein, if it has been determined that the determined amount of the determined correction value exceeds the predetermined nitrogen oxide content threshold, the method further comprises: - Determining an adjustment value based on the determined correction value and the predetermined nitrogen oxide content threshold, wherein the determination of the corrected nitrogen oxide content is based at least partially on the determined adjustment value. [5] Method according to claim 4, wherein determining the adjustment value comprises: - Calculating a difference between the determined correction value and the predetermined nitrogen oxide content threshold. [6] Method according to any one of the preceding claims, further comprising: - Determining a time integral of at least one received first exhaust signal for a predetermined time period, whereby the determination of the correction value is based at least partially on the determined time integral. [7] Method according to claim 6, wherein the predetermined time interval is approximately 5 seconds, approximately 10 seconds or approximately 15 seconds. [8] Method according to any one of claims 1 to 5, further comprising: - Determining a nitrogen oxide content mean value based on at least one received initial exhaust gas signal, wherein the determination of the correction value is based at least partially on the determined nitrogen oxide content mean value. [9] Control device (60) configured to perform the steps of the method according to any of the preceding claims. [10] Control device (60) according to claim 9, comprising: - a first control device section (62) for performing the step of receiving the operating status signal, - a second control device section (64) for performing the step of receiving the at least one first exhaust signal, - a third control device section (66) for performing the step of determining a correction value, - a fourth control device section (68) for performing the step of receiving the at least one second exhaust signal, and - a fifth control device section (69) for performing the step of determining the corrected nitrogen oxide content in the exhaust gas. [11] Catalyst arrangement (10) for an internal combustion engine, comprising: - a storage catalyst (20) designed to treat the exhaust gas of the internal combustion engine and to store at least some nitrogen oxide present in the exhaust gas, at least temporarily, - an exhaust gas sensor (22) arranged downstream of the storage catalyst (20), which is designed to generate a signal that is representative of the nitrogen oxide content in the exhaust gas, and - a control device (60) according to one of claims 9 and 10. [12] Catalyst arrangement (10) according to claim 11, wherein the exhaust gas sensor is a nitrogen oxide sensor (22) configured to generate a nitrogen oxide signal that is representative of the nitrogen oxide content in the exhaust gas of the internal combustion engine. [13] Internal combustion engine for a vehicle with a catalyst device according to one of claims 11 and 12. [14] Computer program comprising instructions which, when executed by a computing unit, cause the computing unit to execute a method according to any one of claims 1 to 8. [15] Computer-readable medium on which the computer program according to claim 14 is stored.

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