Method for taking into account the aging of an exhaust aftertreatment device when operating a drive unit for a motor vehicle, corresponding drive unit for a motor vehicle and computer program product

Abstract

The invention relates to a method for operating a drive unit for a motor vehicle, which has an exhaust-generating drive unit and an exhaust aftertreatment device for treating the exhaust gas. The method uses an exhaust aftertreatment model and an aging parameter describing the aging of the exhaust aftertreatment device to determine the concentration of an exhaust component present in the exhaust gas downstream of the exhaust aftertreatment device. The aging parameter is determined at times based on the oxygen storage capacity of the exhaust aftertreatment device and at other times based on a damage parameter determined using a temperature model for the exhaust aftertreatment device. The invention further relates to a drive unit for a motor vehicle and a computer program.

Description

[0001] The invention relates to a method for operating a drive unit for a motor vehicle, which has an exhaust gas-generating drive unit and an exhaust aftertreatment device for treating the exhaust gas, wherein, by means of an exhaust aftertreatment model and using an aging parameter describing the aging of the exhaust aftertreatment device, a concentration of an exhaust gas component present in the exhaust gas is determined downstream of the exhaust aftertreatment device. The invention further relates to a drive unit for a motor vehicle and a computer program product.

[0002] For example, the prior art document DE 100 55 528 C2 describes a method for determining the aging state of a NOₓ installed in the exhaust system of an internal combustion engine. x-storage catalyst during operation, wherein the temperature and air-fuel ratio are measured in the exhaust stream, the duration of each occurring temperature is determined, and a correction factor for the basic storage capacity of nitrogen oxide is determined as a function of the time-weighted temperatures, and a relative storage capacity of NO x -storage catalyst is calculated as a function of the correction factor and the base storage capacity.

[0003] The plan is to determine the duration of each occurring air number, and to determine the correction factor also depending on the time-weighted air numbers, and to determine the relative NO x -Storage capacity is adaptively adjusted according to the thermal and / or oxidation aging expressed by the correction factor.

[0004] The German patent application DE 10 2020 211 108 B3 relates to a method for adapting a modeled reaction kinetics of at least one reaction taking place in a catalyst using a model-based level control, comprising specifying a target value for at least one level of at least one exhaust gas component that can be stored in the catalyst, calculating at least one level of the catalyst using a signal from an exhaust gas sensor upstream of the catalyst and a catalyst model with at least one storage capacity and a reaction kinetics of the at least one reaction; adjusting an air-fuel mixture depending on the level so that the calculated level approaches the specified target value; and determining a difference between signals from the exhaust gas sensors upstream and downstream of the catalyst.and deactivating the level-dependent adjustment of the air-fuel mixture, and correcting the reaction kinetics of at least one reaction according to a difference between the differences between the signals of the exhaust gas sensors of the catalyst when level-dependent adjustment of the air-fuel mixture is activated and deactivated, as well as a computing unit and a program for its execution.

[0005] The prior art documents DE 10 2017 216 998 A1 and DE 102 48 842 A1 are also known.

[0006] The object of the invention is to propose a method for operating a drive unit for a motor vehicle which has advantages over known methods, in particular taking into account the influence of aging of the exhaust aftertreatment device particularly accurately when calculating the concentration of the exhaust component using the exhaust aftertreatment model.

[0007] According to the invention, this is achieved by a method for operating a drive unit for a motor vehicle with the features of claim 1. It is provided that the aging parameter is determined temporarily based on an oxygen storage capacity of the exhaust aftertreatment device and temporarily based on a damage parameter determined using a temperature model for the exhaust aftertreatment device, wherein the aging parameter is determined by the damage parameter up to a capacity threshold value by the oxygen storage capacity and from the point of falling below this threshold onwards, and / or wherein the aging parameter is determined by the damage parameter up to a damage threshold value by the damage parameter and from the point of exceeding this threshold onwards, on the oxygen storage capacity.

[0008] Advantageous embodiments with expedient further developments of the invention are specified in the dependent claims. It should be noted that the exemplary embodiments described in the description are not limiting; rather, any variations of the features disclosed in the description, the claims, and the figures are possible.

[0009] The method is designed for operating the drive system. It is preferably implemented by means of a control unit for the drive system. The drive system or its control unit is preferably an integral part of the motor vehicle, but can of course also be separate from it, particularly until the drive system or the control unit is mounted on or in the motor vehicle. The drive system serves to propel the motor vehicle, i.e., to provide a drive torque directed towards propelling the motor vehicle. To provide the drive torque, the drive system includes the drive unit. The drive unit is preferably an internal combustion engine, in particular a gasoline engine or a diesel engine.

[0010] During operation, the drive unit is supplied with fuel and fresh gas at least intermittently, with the fresh gas containing fresh air at least intermittently. Additionally, the fresh gas may contain exhaust gas if exhaust gas recirculation is implemented, in which the exhaust gas generated by the drive unit is at least partially returned to the drive unit as a component of the fresh gas. The fuel and fresh gas supplied to the drive unit form a fuel-fresh gas mixture with a specific composition, which is then reacted within the drive unit.

[0011] During operation of the engine, exhaust gas is produced due to the chemical reaction of fuel and fresh air. This exhaust gas is discharged towards the outside environment of the engine or vehicle. Since the exhaust gas generated by the engine contains pollutants, it is first routed to an exhaust aftertreatment system before being released into the environment. In the exhaust aftertreatment system, the pollutants are at least partially converted into less harmful products. Only after passing through the exhaust aftertreatment system is the exhaust gas discharged into the environment, primarily through an exhaust pipe on the engine.

[0012] The exhaust aftertreatment system is preferably designed as a vehicle catalyst, in particular as a three-way catalyst, oxidation catalyst, NO x- Storage catalyst or SCR catalyst. The vehicle catalyst may be integrated into a particulate filter, particularly a gasoline particulate filter or a diesel particulate filter. For this purpose, the particulate filter is, for example, provided with a catalytic coating. The conversion rate, and thus the conversion capacity of the vehicle catalyst, with which the pollutants are converted into less harmful products, depends in particular on the composition of the exhaust gas supplied to the exhaust aftertreatment system or the vehicle catalyst, as well as the temperature of the exhaust aftertreatment system.

[0013] The components of the exhaust gas produced by the engine are also referred to as raw emissions. Raw emissions describe the composition of the exhaust gas upstream of the exhaust aftertreatment system, or, in terms of flow dynamics, between the engine and the exhaust aftertreatment system. As the exhaust gas passes through the aftertreatment system, some of the substances contained within it are transformed, thus changing its composition. The substances present in the exhaust gas downstream of the aftertreatment system, which constitute the exhaust gas, are also referred to as tailpipe emissions, since this is the composition of the exhaust gas released into the environment through the engine's tailpipe.

[0014] As mentioned earlier, the amount of pollutants contained in the tailpipe emissions depends on the raw emissions, but also on the conversion efficiency of the exhaust aftertreatment system or the vehicle's catalytic converter. This efficiency is temperature-dependent. In particular, the conversion efficiency is lower the further the temperature of the exhaust aftertreatment system deviates from its operating temperature; that is, the greater the absolute difference between the temperatures. The temperature of the exhaust aftertreatment system refers, for example, to the temperature of a ceramic honeycomb structure coated with the catalytic material.

[0015] To determine the pollutant emissions of the propulsion system, i.e., the quantity of at least one exhaust component released into the environment, the exhaust aftertreatment model is used. This model simulates the conversion of at least one exhaust component by the aftertreatment system. For this purpose, the model receives an input input of the inlet concentration of the at least one exhaust component, which is present upstream of the aftertreatment system. The output output of the model is the concentration of the exhaust component downstream of the aftertreatment system, also known as the outlet concentration. In principle, any number of outlet concentrations of any number of exhaust components can be determined using the exhaust aftertreatment model.

[0016] The inlet concentration can be determined in any desired way; for example, it can be determined as a function of an operating point of the drive unit, where the operating point is characterized, for example, by the drive torque currently provided by the drive unit and / or an instantaneous rotational speed of the drive unit. For example, the inlet concentration could be equal to the raw emission of the drive unit, i.e., equal to the quantity of at least one exhaust component produced or emitted by the drive unit.

[0017] As a further input variable, the exhaust aftertreatment model receives, for example, an air-fuel ratio. It is intended, for instance, to set the inlet air-fuel ratio equal to an air-fuel ratio determined from a measurement taken by a lambda sensor upstream of the exhaust aftertreatment system and / or a measurement taken by a lambda sensor downstream of the exhaust aftertreatment system. The measurement thus describes the air-fuel ratio present in the exhaust gas upstream or downstream of the exhaust aftertreatment system, or a quantity of residual oxygen present in the exhaust gas at that point.

[0018] The conversion efficiency of the exhaust aftertreatment system is also significantly dependent on its aging. The older the exhaust aftertreatment system, the lower its conversion efficiency typically is. Therefore, to reliably determine the concentration of the exhaust component using the exhaust aftertreatment model during operation of the propulsion system, particularly over the entire service life of the system, it is necessary to account for this aging. For this reason, the aging parameter is determined and fed into the exhaust aftertreatment model as an input.

[0019] Ultimately, the exhaust gas component's discharge concentration depends significantly on the inlet concentration and the aging factor. Accordingly, it is crucial to determine the aging factor with high accuracy. For example, the aging factor is determined based on the oxygen storage capacity of the exhaust aftertreatment system. The oxygen storage capacity describes the maximum amount of oxygen that the exhaust aftertreatment system can temporarily store, particularly due to a chemical reaction occurring within the system.

[0020] The oxygen storage capacity typically decreases with the aging of the exhaust aftertreatment system, and is therefore considered a reliable measure of aging. However, the applicant has surprisingly found that the oxygen storage capacity is not consistently sufficient to accurately account for aging. For this reason, the invention proposes to determine the aging parameter temporarily, and in particular only temporarily, based on the oxygen storage capacity. Additionally, when determining the aging parameter, the damage parameter, which is determined using the temperature model, is also used temporarily, and in particular only temporarily.

[0021] Therefore, it is not intended to determine the aging parameter consistently from the oxygen storage capacity or consistently from the damage parameter, but rather to consider one of the two parameters under certain conditions. The damage parameter is understood to be a parameter that describes the damage to the exhaust aftertreatment system over time due to the influence of temperature on the exhaust aftertreatment system. The exhaust aftertreatment system is designed for a specific operating temperature at which it exhibits its highest average conversion efficiency for the exhaust component or components.

[0022] If the temperature of the exhaust aftertreatment system corresponds to this operating temperature, a certain degree of damage occurs over time; the aging of the exhaust aftertreatment system thus progresses at a certain rate. If the temperature deviates from the operating temperature, aging can be more or less pronounced. This is taken into account using the damage parameter. This ensures high accuracy in determining the aging parameter and, consequently, high accuracy in determining the concentration of the exhaust gas component using the exhaust aftertreatment model.

[0023] Preferably, the oxygen storage capacity is determined during a diagnostic check of the exhaust aftertreatment system. During the diagnostic check, for example, the oxygen storage tank of the exhaust aftertreatment system is completely emptied and subsequently completely filled, or vice versa. Whether the oxygen storage tank is completely full or completely emptied is determined using one or more lambda sensors. The oxygen storage capacity is then determined by measuring the oxygen supplied to and / or discharged from the exhaust aftertreatment system during the diagnostic check. Of course, other methods are also feasible, provided they allow for a sufficiently accurate determination of the oxygen storage capacity.

[0024] A further development of the invention provides that the temperature model is used to determine the influence temperature of the exhaust aftertreatment system and to determine the damage magnitude based on this influence temperature. The temperature model determines the influence temperature as an output variable from one or more input variables. The influence temperature describes the temperature to which the exhaust aftertreatment system is exposed. Thus, the influence temperature describes, for example, the actual temperature of the exhaust aftertreatment system or a temperature that theoretically exists within the exhaust aftertreatment system. The damage magnitude is determined from the influence temperature; in particular, the damage magnitude is expressed as a function of the influence temperature. Preferably, the damage magnitude is greater the higher the influence temperature.The described procedure enables an accurate estimation of the aging of the exhaust aftertreatment system and a correspondingly accurate determination of the aging parameter.

[0025] A further development of the invention provides that the influence temperature is determined from a measured temperature and / or an operating parameter of the drive unit. The measured temperature is a temperature that is measured using a temperature sensor. It can be provided that the influence temperature is set equal to this measured temperature. Additionally or alternatively, the operating parameter of the drive unit is taken into account when determining the influence temperature. The operating parameter is a parameter that directly influences and / or describes the operation of the drive unit. For example, the operating parameter describes the operating point of the drive unit and / or a fuel flow rate, i.e., a quantity of fuel supplied to the drive unit per unit of time during its operation.It is particularly advantageous to have the influence temperature as a function of both the measured temperature and the operating parameter. The described procedure achieves high accuracy in determining the aging parameter.

[0026] A further development of the invention provides that the measured temperature is the exhaust gas temperature of the exhaust gas measured upstream or downstream of the exhaust aftertreatment device. A temperature sensor is thus located upstream or downstream of the exhaust aftertreatment device, by means of which the temperature of the exhaust gas is measured. For example, the temperature is measured directly upstream or directly downstream of the exhaust aftertreatment device. Of course, it is also possible to measure a temperature both upstream and downstream of the exhaust aftertreatment device and to determine the measured temperature from both temperatures, particularly in the form of an average value or the like. The described procedure achieves a high degree of accuracy in determining the aging parameter.

[0027] A further development of the invention provides that a temperature difference occurring due to an exothermic reaction of the exhaust gas in the exhaust aftertreatment system is determined from the operating parameter of the drive unit and used to determine the influence temperature. The influence temperature is thus affected by the temperature difference. For example, the influence temperature is the sum of the measured temperature and the temperature difference. The temperature difference results from the exothermic reaction of the exhaust gas, or at least one exhaust gas component, occurring in the exhaust aftertreatment system. Examples of exothermic reactions include the oxidation of carbon monoxide, the oxidation of unburned hydrocarbons, or the reduction of nitrogen oxides.

[0028] The exothermic reaction causes a local temperature increase in the exhaust aftertreatment system and thus significantly influences its aging. Therefore, it should be considered when determining the extent of damage. This is done using the operating parameter that determines the composition of the exhaust gas upstream of the aftertreatment system. This composition is also referred to as the raw emission from the engine. Based on the exhaust gas composition, it can be deduced whether and to what extent the exothermic reaction occurs in the aftertreatment system. The temperature difference is thus a function of the engine's operating parameter, and the influencing temperature is, in turn, a function of this temperature difference. The described procedure allows for a particularly precise consideration of the aging of the exhaust aftertreatment system.

[0029] A further development of the invention provides that a fuel flow rate is used as an operating parameter, which determines the amount of fuel supplied to the drive unit. The fuel flow rate describes the quantity of fuel supplied to the drive unit per unit of time. This quantity can be expressed, for example, as a mass or volume of fuel. The fuel flow rate enables a particularly precise determination of whether and to what extent the exothermic reaction occurs, allowing the temperature difference to be derived from the operating parameter. This approach also contributes to achieving a high degree of accuracy in determining the aging parameter.

[0030] A further development of the invention provides that, based on the influencing temperature and / or a time parameter, a damage data set is selected from several damage data sets, each containing a value of the influencing temperature and / or a value of the time parameter on the one hand and a value of a partial damage parameter on the other. The damage parameter is then determined from the value of the partial damage parameter stored in the selected damage data set, in particular by addition and / or integration. The damage data sets are stored in the drive unit, preferably in the control unit used to carry out the described method.

[0031] The damage data records describe the influence of the influencing temperature or the time parameter on the damage parameter, specifically using the partial damage parameter. The partial damage parameter, or its value, thus describes the respective influence of the influencing temperature or the time parameter on the damage parameter. If the influencing temperature is used to select the damage data record, the damage data records contain both the value of the influencing temperature and the value of the partial damage parameter. If, on the other hand, the time parameter is used, the damage data records contain both the value of the time parameter and the value of the partial damage parameter.

[0032] Based on the influencing temperature or time parameter, the relevant damage data record is selected from the damage data records, and the value of the partial damage parameter stored within that record is extracted. This partial damage parameter is then used to determine the overall damage parameter; preferably, the overall damage parameter is incremented by the value of the partial damage parameter, resulting in the calculated damage parameter through addition or integration.

[0033] If the ambient temperature is used to select the damage data set, the corresponding value of the partial damage parameter is stored in the damage data sets for different ambient temperature values. In this approach, the ambient temperature actually measured on board the vehicle is used to determine the value of the partial damage parameter and to calculate the overall damage parameter. However, if the time parameter is the one used to select the damage data set, the values ​​of the partial damage parameter stored in the damage data sets were not determined based on an actual ambient temperature, but rather calculated for a statistically probable ambient temperature profile and stored in the drive system.

[0034] Using the influence temperature allows for a particularly precise consideration of the actual temperature acting on the exhaust aftertreatment system; however, statistically considering the influence temperature based on the time parameter may be sufficient. The time parameter describes, in particular, the operating time of the exhaust aftertreatment system, specifically its accumulated operating time over its entire service life.

[0035] The invention provides that the aging parameter is determined by the oxygen storage capacity up to the point where a capacity threshold is undershot, based on the damage parameter, and from the point where the threshold is undershot, based on the oxygen storage capacity, and / or that the aging parameter is determined by the damage parameter up to the point where a damage threshold is exceeded, based on the damage parameter, and from the point where the threshold is exceeded, based on the oxygen storage capacity.

[0036] In principle, the aging parameter can be determined using different approaches. According to one approach, the damage parameter is decisive for the aging parameter until the oxygen storage capacity falls below the capacity threshold, i.e., becomes smaller than it. As long as the oxygen storage capacity is at least equal to the capacity threshold, the aging parameter is determined from the damage parameter, preferably exclusively from the damage parameter. Once the oxygen storage capacity falls below the capacity threshold, the oxygen storage capacity is used to determine the aging parameter, preferably exclusively.

[0037] According to a second variant, the damage magnitude is used to determine whether the aging magnitude is derived from the damage magnitude or the oxygen storage capacity. As long as the damage magnitude is less than the damage threshold, the aging magnitude is derived from the damage magnitude, preferably exclusively from it. Once the damage magnitude exceeds the damage threshold, the aging magnitude is derived from the oxygen storage capacity, preferably exclusively.

[0038] According to a third, non-inventive embodiment, it is provided that a first partial quantity is determined from the oxygen storage capacity and a second partial quantity from the damage quantity. The first and second partial quantities are then used to determine the aging quantity; for example, the aging quantity is obtained by adding the first and second partial quantities, or the larger or smaller of the partial quantities is used as the aging quantity. In each case, a high accuracy of the aging quantity is achieved.

[0039] A further development of the invention provides that the exhaust aftertreatment model determines the concentration of the exhaust gas component based on a reaction rate and / or a temperature threshold, both determined as a function of the aging parameter. Within the framework of the exhaust aftertreatment model, the concentration, or rather the initial concentration, is derived from the input concentration, the reaction rate, and / or the temperature threshold.

[0040] The reaction rate describes the speed or extent to which the exhaust gas component is converted during its passage through the exhaust aftertreatment system. The temperature threshold, on the other hand, describes whether the reaction occurs at all. For example, the temperature threshold is a lower or upper limit for the temperature. The reaction rate and / or the temperature threshold are preferably expressed as a function of the aging parameter; thus, the aging parameter influences either the reaction rate, the temperature threshold, or both.

[0041] For example, the reaction rate is adjusted by a correction factor, in particular by multiplication, which is determined from the aging parameter. For the temperature threshold, an offset is preferably determined from the aging parameter, which is then added to or subtracted from the temperature threshold. This approach allows the aging of the exhaust aftertreatment system to be taken into account particularly precisely when determining the discharge concentration.

[0042] The invention further relates to a drive unit for a motor vehicle, in particular for carrying out the method according to the description in this document, wherein the drive unit has an exhaust gas generating drive unit and an exhaust gas aftertreatment device for aftertreatment of the exhaust gas, and wherein the drive unit is provided and designed to determine a concentration of an exhaust gas component present in the exhaust gas downstream of the exhaust gas aftertreatment device by means of an exhaust gas aftertreatment model using an aging parameter describing the aging of the exhaust gas aftertreatment device.

[0043] The drive unit is also designed and configured to determine the aging parameter temporarily based on the oxygen storage capacity of the exhaust aftertreatment system and temporarily based on a damage parameter determined using a temperature model for the exhaust aftertreatment system. The aging parameter is determined by the damage parameter until a capacity threshold is reached, and then again based on the oxygen storage capacity from the point of falling below this threshold. Alternatively, the aging parameter is determined by the damage parameter until a damage threshold is exceeded, and then again based on the oxygen storage capacity from the point of exceeding this threshold. The advantages of such a drive unit design and procedure have already been mentioned.Both the drive device and the method for operating it may be further developed in accordance with the explanations within this description, so reference is made to these in this respect.

[0044] Furthermore, the invention relates to a computer program product comprising commands that cause the drive device to execute the described method as described herein. For the advantages and possible advantageous embodiments, reference is made to the description in its entirety.

[0045] The features and combinations of features described in the description, in particular those described in the following figure description and / or shown in the figures, are not only usable in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention, in particular the scope of the claims. Thus, embodiments that are not explicitly shown or explained in the description and / or the figures, but which emerge from or can be derived from the explained embodiments, particularly within the scope of the claims, are also to be considered as encompassed by the invention.

[0046] The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing, without limiting the invention. The only embodiment shown is... Fig. 1 a diagram which illustrates a method for operating a drive unit for a motor vehicle.

[0047] The Fig.Figure 1 shows a diagram illustrating, purely by way of example, a method for operating a drive unit for a motor vehicle. The drive unit comprises an exhaust gas-generating drive unit and an exhaust aftertreatment system for treating this exhaust gas. Preferably, a first lambda sensor is located upstream of the exhaust aftertreatment system and a second lambda sensor is located downstream of the exhaust aftertreatment system, with each lambda sensor determining the air-fuel ratio present in the exhaust gas. For example, the first lambda sensor is configured as a wideband lambda sensor and the second lambda sensor as a narrowband lambda sensor. However, the lambda sensors are optional and, at most, of minor importance for the method described here.

[0048] The diagram shows curves 1, 2, 3, and 4, plotted over time as examples. Instead of time, the vehicle's mileage can also be used. Curve 1 represents the oxygen storage capacity of the exhaust aftertreatment system, curve 2 represents an aging parameter that actually describes the aging of the exhaust aftertreatment system, curve 3 represents the first component of the aging parameter derived from the oxygen storage capacity, and curve 4 represents the second component of the aging parameter derived from a damage parameter.

[0049] It is evident that the oxygen storage capacity is greater than capacity C1 up to time t1 and also decreases relatively slowly. Only from time t1 onwards, or from reaching capacity C1, does the oxygen storage capacity decrease more rapidly until it reaches capacity C2 at time t2. Once the oxygen storage capacity falls below capacity C2, the exhaust aftertreatment system needs to be replaced.

[0050] Graph 2 shows the actual influence of exhaust aftertreatment system aging on the system's conversion performance. It describes this aging in the form of an aging parameter. It is evident that this parameter increases continuously, with the rate of increase accelerating from time t1 onwards. Graph 3 shows a partial value of the aging parameter, which is derived solely from the oxygen storage capacity of graph 1. Accordingly, graph 3 is inversely similar to graph 1. Furthermore, it is apparent that graph 3 only inadequately represents the actual aging parameter of graph 2, particularly up to time t1.

[0051] For this reason, the first component is only used to determine the aging parameter from time t1 onwards. Until time t1 is reached, the aging parameter is determined from a second component, which is calculated using a damage parameter derived from a temperature model for the exhaust aftertreatment system. The second component is shown in Figure 4. It can be seen that the second component better represents the damage parameter up to time t1 than the first component.

[0052] Accordingly, the aging parameter is to be determined temporarily based on the first component and temporarily based on the second component. The first component is determined using the oxygen storage capacity of the exhaust aftertreatment system, and the second component using the damage parameter. This yields a precise value for the aging parameter, and from this, in turn, a precise determination of the conversion performance of the exhaust aftertreatment system is possible. REFERENCE MARK LIST: 1. Course 2 Course 3 Course 4. Course

Claims

[1] Method for operating a drive unit for a motor vehicle which has an exhaust gas generating drive unit and an exhaust gas aftertreatment device for aftertreatment of the exhaust gas, wherein an exhaust gas aftertreatment model is used to determine a concentration of an exhaust gas component present in the exhaust gas downstream of the exhaust gas aftertreatment device using an aging parameter describing the aging of the exhaust gas aftertreatment device, characterized by, that the aging parameter is determined temporarily based on an oxygen storage capacity of the exhaust aftertreatment device and temporarily based on a damage parameter determined using a temperature model for the exhaust aftertreatment device, wherein the aging parameter is determined by the damage parameter until a capacity threshold is undershot, and from the point of undershot, by the oxygen storage capacity, and / or wherein the aging parameter is determined by the damage parameter until a damage threshold is exceeded, and from the point of exceedance, by the oxygen storage capacity. [2] Method according to claim 1, characterized by , that the temperature model is used to determine the influence temperature of the exhaust aftertreatment system and the damage magnitude is determined based on the influence temperature. [3] Method according to claim 2, characterized by , that the influencing temperature is determined from a measured temperature and / or an operating parameter of the drive unit. [4] Method according to claim 3, characterized by , that the measured temperature is an exhaust gas temperature of the exhaust gas measured upstream or downstream of the exhaust gas aftertreatment device. [5] Method according to any one of claims 2 to 4, characterized by , that a temperature difference occurring due to an exothermic reaction of the exhaust gas in the exhaust aftertreatment device is determined from the operating parameter of the drive unit and is used in determining the influence temperature. [6] Method according to any one of the preceding claims, characterized by, that based on the influence temperature and / or a time parameter, a damage data set is selected from several damage data sets, in which each contains a value of the influence temperature and / or a value of the time parameter on the one hand and a value of a partial damage parameter on the other, and the damage parameter is determined from the value of the partial damage parameter stored in the selected damage data set. [7] Method according to any one of the preceding claims, characterized by , that the exhaust aftertreatment model determines the concentration of the exhaust component based on a reaction rate determined depending on the aging parameter and / or a temperature threshold determined depending on the aging parameter. [8] Drive unit for a motor vehicle, in particular for carrying out the method according to one or more of the preceding claims, wherein the drive unit has an exhaust gas generating drive unit and an exhaust gas aftertreatment device for aftertreatment of the exhaust gas, and wherein the drive unit is provided and designed to determine, by means of an exhaust gas aftertreatment model using an aging parameter describing an aging of the exhaust gas aftertreatment device, a concentration of an exhaust gas component present in the exhaust gas downstream of the exhaust gas aftertreatment device, characterized by that the drive unit is also designed and configured to temporarily measure the aging rate based on an oxygen storage capacity of the exhaust aftertreatment device and temporarily based on a damage magnitude determined using a temperature model for the exhaust aftertreatment device, wherein the aging magnitude is determined up to a capacity threshold by the oxygen storage capacity based on the damage magnitude and from the point of falling below it based on the oxygen storage capacity, and / or wherein the aging magnitude is determined up to a damage threshold by the damage magnitude based on the damage magnitude and from the point of exceeding it based on the oxygen storage capacity. [9] Computer program product comprising instructions that cause the drive device according to claim 8 to execute the method according to one or more of claims 1 to 7.

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