Method for 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, wherein an operating parameter is set on the drive unit to provide a drive torque. It is provided that, after completion of a warm-up operation, within the framework of an optimization process based on a torque map (7), a parameter map (8), and an exhaust component map (9) for a temperature parameter (10), the torque parameter (11) is determined which, by fulfilling an exhaust component parameter (13), satisfies a torque condition. The invention further relates to a drive unit for a motor vehicle and a computer program product.

Description

[0001] 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, wherein an operating parameter is set on the drive unit to provide drive torque. 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 10 2022 202 013 A1 describes a method for exhaust gas temperature control for a combustion engine-powered motor vehicle with a cascaded, decoupled control system embedded in the motor vehicle's engine control unit, which includes an inner control loop for controlling a modeled actual exhaust gas temperature of an exhaust gas from a combustion engine and an outer control loop for controlling a modeled and real actual component temperature of a component that absorbs or releases heat through the exhaust gas.

[0003] Furthermore, it is provided that, at least when the modeled and / or actual component temperature of the component is detected as having been reached or exceeded above a maximum component temperature stored in the engine control unit, the outer control loop or a real temperature sensor will a) reduce the detected modeled actual exhaust gas temperature to a modeled target exhaust gas temperature by the inner control loop, at which the modeled actual component temperature is below the stored maximum component temperature, by reducing a modeled actual engine load of the engine to a modeled target engine load and / or by increasing a modeled actual combustion air ratio to a modeled target combustion air ratio;

[0004] Furthermore, it is provided that b) the actual engine load of the engine is adjusted to the modeled target engine load of the engine and the actual combustion air ratio of the engine is adjusted to the modeled target combustion air ratio of the engine by the engine control unit by controlling the engine and / or a preparation component functionally assigned to the engine.

[0005] Furthermore, from German patent application DE 10 2018 126 419 A1, an emission control system for treating exhaust gas in a motor vehicle with an internal combustion engine is known, the emission control system comprising: an electric diesel oxidation catalyst device in an exhaust gas stream; a temperature sensor on the diesel oxidation catalyst device and configured to detect an exhaust gas temperature; and a controller configured to perform model-based control of the diesel oxidation catalyst device, based on a dual nested closed-loop control topology with an inner closed-loop control system and an outer closed-loop control system; wherein the inner-loop control system is configured to control the power for the diesel oxidation catalyst device; and wherein the outer-loop control system is configured to control the temperature of the diesel oxidation catalyst device.

[0006] German patent application DE 10 2004 033 969 B4 discloses a method for controlling the temperature downstream of a catalytic converter in the exhaust system of an internal combustion engine. This method comprises a first, outer control loop in which a first manipulated variable is formed from a first control deviation, which is derived from a first actual value and a first setpoint, where the first actual value is determined as a measure of the temperature downstream of the catalytic converter. A second, inner control loop is provided in which at least one second manipulated variable is formed from a second control deviation, which is derived from a second actual value and a second setpoint, where the second actual value is determined as a temperature upstream of the catalytic converter, and where the second manipulated variable influences internal engine heat generation.

[0007] German patent application DE 10 2023 203 419 A1 relates to a method for operating a drive unit for a motor vehicle, which has an exhaust gas-generating drive unit and is operated according to a value of at least one operating parameter. It is provided that, at least temporarily, the quantity of an exhaust gas component in the exhaust gas is determined, and the value for the at least one operating parameter is read from a characteristic map using the quantity of the exhaust gas component and a threshold value for the quantity of the exhaust gas component, and used to operate the drive unit.

[0008] 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 enabling optimal operation with regard to the drive torque provided by the drive unit during warm-up operation.

[0009] 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.The system provides that during a warm-up phase of the drive unit, a torque parameter describing the drive torque is stored in a torque map as a function of a temperature parameter describing the temperature of the exhaust aftertreatment system; a parameter parameter describing the operating parameter is stored in a parameter map as a function of the temperature parameter and the torque parameter; and an exhaust component parameter describing the quantity of an exhaust component in the exhaust gas is stored in an exhaust component map as a function of the parameter parameter. After completion of the warm-up phase, an optimization process is performed using the torque map, the parameter map, and the exhaust component map to determine the torque parameter that fulfills a torque condition based on the exhaust component parameter.

[0010] 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.

[0011] 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. The drive unit comprises the drive system to provide the drive torque. The drive unit is preferably an internal combustion engine, in particular a gasoline engine or a diesel engine.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] As part of the process, the operating parameter is determined and set on the drive unit. The operating parameter describes a parameter that directly influences the operation of the drive unit and / or the drive torque it provides. For example, an air charge, preferably a relative air charge, and / or an ignition timing is used as an operating parameter. In a given application of the drive unit, different values ​​of the operating parameter are assigned to different values ​​of the drive torque. During operation, a value of the operating parameter is selected based on the drive torque, for example, based on a preset value of the drive torque, and set on the drive unit.This is readily possible for quasi-stationary operation of the drive unit, in which the temperature of the exhaust aftertreatment unit has already reached the operating temperature of the exhaust aftertreatment unit.

[0018] However, adjusting the drive system for warm-up operation remains challenging, especially if this is to be done based on RDE (Real Driving Emissions) data from the vehicle's driving cycles, which are only available to a limited extent and with limited resolution. Warm-up operation refers to the operation of the drive system during which the exhaust aftertreatment system operates at a temperature lower than its operating temperature. The operating temperature of the exhaust aftertreatment system, in turn, describes the temperature at which the system achieves a specific conversion rate for certain exhaust gas components.

[0019] For this reason, the warm-up process is to be optimized. To this end, the torque map, the parameter map, and the exhaust gas component map are used. The torque map contains the torque value as a function of temperature, the parameter map contains the parameter value as a function of both temperature and torque, and the exhaust gas component map contains the exhaust gas component value as a function of the parameter value.

[0020] The torque parameter describes the drive torque; for example, it may correspond to it. However, it is also possible for the torque parameter to contain multiple torque values ​​for the drive torque. Similarly, the temperature parameter can correspond to the temperature of the exhaust aftertreatment system or contain multiple temperature values. This also applies analogously to the parameter parameter, which corresponds to the operating parameter or contains multiple operating parameter values, as well as to the exhaust component parameter, which, for example, corresponds to the quantity of exhaust components or contains multiple component quantity values.

[0021] In the case of multiple values, the temperature parameter, for example, describes a temperature range, the torque parameter a torque range, the parameter parameter an operating parameter range, and the exhaust component parameter a quantity range for the exhaust component. During warm-up, the temperature parameter, torque parameter, parameter parameter, and exhaust component parameter are determined and stored in the respective characteristic map. This occurs particularly during one or more RDE cycles (RDE: Real Driving Emissions). The exhaust component parameter describes the quantity of one or more exhaust components for the parameter parameter, especially in the form of the mass of the exhaust component, for example, the mass of the exhaust component accumulated over a distance traveled by the vehicle. Examples of exhaust components used include nitrogen oxides (NOx) and / or carbon monoxide (CO).

[0022] After the warm-up phase is complete, for example, immediately upon reaching operating temperature via the exhaust aftertreatment system or after the drive system has finished operating, the warm-up process is optimized. During this optimization, the characteristic maps—specifically the torque map, the parameter map, and the exhaust component map—are used to determine a torque value for a given temperature. This determination of the torque value as a function of temperature is carried out in such a way that both the torque value and the exhaust component value fulfill the exhaust component condition.For example, the torque condition is chosen such that when determining the torque quantity, the torque quantity is determined which corresponds to the maximum possible drive torque while simultaneously complying with the exhaust component condition through the exhaust component size.

[0023] The torque value is stored as a function of the temperature, for example, in the torque map or in a separate map. When the drive unit is subsequently operated during warm-up, the torque value is read from the torque map or the separate map, depending on the temperature of the exhaust aftertreatment system, and used to operate the drive unit or drive system. This means, in particular, that the drive torque provided by the drive system is limited to the torque corresponding to the read-out torque value. This procedure ensures that, on the one hand, the highest possible drive torque can always be provided, and on the other hand, emission limits are reliably met.

[0024] A further development of the invention provides that the storage of the torque value in the torque map, the storage of the parameter value in the parameter map, and the storage of the exhaust component value in the exhaust component map are carried out by means of a control unit of the drive system. The control unit serves to control the drive system or the drive unit. The control unit is therefore, in particular, in the form of an engine control unit. The control unit serves to select and set the operating parameter at the drive unit to provide the drive torque.

[0025] For example, the control unit receives a target torque as an input, which is specified, in particular, by a vehicle user and / or a driver assistance system. Based on this target torque, the control unit determines the drive torque that the drive unit can provide and controls the drive unit to deliver this drive torque. As long as the target torque is equal to or less than the aforementioned torque, the target torque is used as the drive torque. However, if it is greater than the torque, the drive torque is limited to this higher torque. The drive torque thus corresponds to the target torque, but not exceeding the torque read from the control unit.

[0026] Preferably, the control unit is operated according to the procedure described in German patent applications DE 10 2020 111 204 A1, DE 10 2020 111 206 A1, and DE 10 2020 111 208 A1. The disclosures of the aforementioned patent applications are fully incorporated into the present description by reference. Patent application DE 10 2020 111 204 A1 describes a method for operating a control unit for a motor vehicle, wherein n-dimensional reference input vectors are each assigned a reference output vector, from which an output vector is determined for an n-dimensional input vector, performing the following steps: a. Repeat the following steps until a reference input vector exists in an n-dimensional space around the input vector whose distance to the input vector falls below a threshold value, and / or a maximum number of iterations is reached: i. Selecting at least one neighboring vector from the reference input vectors, ii. Determining an additional reference input vector from the at least one neighboring vector and adding the additional reference input vector to the reference input vectors; b. Selecting at least one calculation vector closest to the input vector from the reference input vectors and calculating the output vector based on the least one selected calculation vector.

[0027] The n-dimensional reference input vectors and the reference output vectors define the characteristic map and are, respectively, embedded within it. The n-dimensional input vector is defined by input variables, with each input variable representing a dimension of the input vector. In the case of the procedure described here, the torque characteristic map, for example, has a one-dimensional or multi-dimensional input vector that includes the temperature variable. The input vector is one-dimensional if the temperature variable consists of only a single temperature value, or multi-dimensional if the temperature variable comprises multiple temperature values. The output vector contains the torque variable.

[0028] For the parameter map, the input vector contains both the temperature and torque values, while the output vector contains the parameter value. For the exhaust gas component map, the input vector contains the parameter value and the output vector contains the exhaust gas component value. During optimization, the respective values ​​that are part of the corresponding output vector are read from the respective map in the manner described.

[0029] The adaptation of the characteristic maps during warm-up operation is particularly preferably carried out according to the procedure described in German patent application DE 10 2020 111 206 A1. This describes a method for operating a control unit for a motor vehicle, wherein n-dimensional reference input vectors are each assigned a reference output vector, from which an output vector can be determined for at least one n-dimensional input vector, and wherein, when a new reference input vector with a corresponding new reference output vector is available, the following steps are carried out: a. Determining a single error of the reference input vectors; b. Temporarily storing the reference input vector with the smallest single error and removing this reference input vector from the reference input vectors; c. Calculate the output vector using the new reference input vector as the input vector; d. Determining the individual error from a difference between the output vector and the reference output vector assigned to the new reference input vector; e. Adding the remote reference input vector to the reference input vectors; f. Replacing the reference input vector with the smallest single error with the new reference input vector if the single error of the new reference input vector is larger than the smallest single error.

[0030] The control unit preferably corresponds to the aforementioned control unit. The n-dimensional reference input vectors and the corresponding reference output vectors define the respective characteristic map; thus, reference input vectors and corresponding reference output vectors are provided for the torque characteristic map, the parameter characteristic map, and the exhaust component characteristic map. Preferably, the characteristic maps are adapted according to claim 1 of German patent application DE 10 2020 111 206 A1. The procedure can be further developed according to one or more of claims 2 to 10 of this patent application. Additional advantageous developments are included in the description of the patent application and can optionally be used to further develop the described method. The content of the patent application is fully incorporated into the present description by reference.

[0031] The described procedure serves to improve the engine map directly during vehicle operation; therefore, no intermediate storage of values ​​or post-operational optimization of the engine maps is necessary. Rather, the computing power of the control unit is entirely sufficient to perform both the adaptation and optimization of the engine maps.

[0032] A further development of the invention provides that the torque value fulfilling the torque condition, in particular the value corresponding to the maximum possible drive torque, is stored in a characteristic map as a function of the temperature, and that when the drive device is operated, the drive torque set on the drive unit is limited to a maximum torque that is read from the characteristic map as a function of the temperature of the exhaust aftertreatment system. Such a procedure has already been mentioned.

[0033] It may be intended that the torque map is used as the characteristic map. Alternatively, the characteristic map can be a different map altogether. Using this map, the maximum torque achievable by the exhaust component and the drive unit, while adhering to the exhaust component conditions, is determined. The drive torque is then limited to this maximum torque. For example, it is possible to first set the drive torque to the aforementioned target torque and then limit it to the maximum torque. The described procedure achieves the advantages already mentioned.

[0034] A further development of the invention provides that, for optimization within a first model, the torque value is read from the torque map based on the temperature value; within a second model, the parameter value is read from the parameter map based on both the temperature and torque values; and within a third model, the exhaust gas component value is read from the exhaust gas component map based on the parameter value. The first model thus models the torque value as a function of the temperature value, the second model the parameter value as a function of both the temperature and torque values, and the third model the exhaust gas component value as a function of the parameter value. Ultimately, the first model is based on the torque map, the second model on the parameter map, and the third model on the exhaust gas component map.The reading from the characteristic maps is preferably carried out according to the procedure described in the patent application DE 10 20 2011 204 A1, in particular according to claim 1 therein. This enables a particularly efficient optimization of the drive torque.

[0035] A further development of the invention provides that an external optimization loop is performed for optimization purposes, in which the torque value is adjusted towards a higher drive torque such that the exhaust component size determined for the adjusted torque value based on the parameter map and the exhaust component map fulfills the exhaust component condition. First, an initial value for the torque value is determined, in particular by reading it from the torque map as a function of the temperature of the exhaust aftertreatment system. The parameter value for the torque value is then determined based on the parameter map, in particular taking the temperature or temperature value into additional consideration. The parameter value is then used to determine the exhaust component size using the exhaust component map.

[0036] Within the outer optimization loop, the torque value is then adjusted towards the higher drive torque, and the exhaust component size is determined again using the described procedure. This adjustment of the torque value towards the higher drive torque continues as long as the exhaust component size meets the exhaust component condition. The exhaust component condition is, for example, a limit value or threshold for the exhaust component size. The exhaust component condition therefore requires that the exhaust component size be smaller than the limit value or threshold.

[0037] If the exhaust component size describes multiple exhaust components, a separate exhaust component condition is preferably defined for each component, which the exhaust component size must fulfill for that specific component. The torque value corresponding to the highest drive torque, for which the exhaust component condition is fulfilled by the exhaust component size, is stored, particularly in the aforementioned characteristic map. This approach achieves a stepwise optimization of the warm-up operation of the drive unit.

[0038] A further development of the invention provides that an inner optimization loop is executed within the outer optimization loop, in which the parameter size is adjusted until the exhaust component size read from the exhaust component map fulfills the exhaust component condition and / or a further exhaust component condition. The inner optimization loop is carried out based on the torque value specified by the outer optimization loop.

[0039] The inner optimization loop adjusts the parameter size for the given torque value until the exhaust component size meets the exhaust component condition or a different, additional exhaust component condition. The additional exhaust component condition might, for example, require minimizing the quantity of the exhaust component or the quantities of the exhaust components. In particular, it requires minimizing the sum of the exhaust component quantities.

[0040] If, within the inner optimization loop, a parameter size is determined for the torque quantity for which the exhaust component condition is met, the inner optimization loop is terminated and the outer optimization loop is continued, namely by further adjusting the torque quantity in the direction of the larger drive torque within the outer optimization loop.

[0041] If, however, no parameter value can be found within the inner optimization loop for which the exhaust component condition is met, the inner optimization loop is also terminated and the process returns to the outer optimization loop. The outer optimization loop is also terminated in this case, returning as its result the torque value for which the exhaust component condition was last met. This torque value is stored, particularly in the characteristic map, and / or used to operate the drive system or drive unit. This results in the rapid and efficient optimization of the warm-up process.

[0042] A further development of the invention provides that the parameter size is adjusted in such a way that the drive unit, when operated with the parameter size describing the operating parameter, continues to generate the drive torque described by the torque value. In particular, the inner optimization loop is performed while maintaining the drive torque; no change in the drive torque should occur as a result of the optimization. The adjustment of the drive torque is only carried out within the outer optimization loop to determine the maximum possible torque at which the exhaust gas component condition is still met. This also serves to quickly optimize the operation of the drive unit.

[0043] A further development of the invention provides that the temperature parameter contains multiple temperatures, the torque parameter contains multiple torque values, and the exhaust gas component parameter contains multiple component quantities, in particular a minimum value, a maximum value, and / or a nominal value in each case. The characteristic maps, especially the torque characteristic map, thus do not merely assign a drive torque value to a temperature value, but rather a drive torque range to a temperature range. By considering the multiple temperatures or the temperature range holistically, the sensitivity of the model is kept low, thus preventing incorrect synchronization between the torque parameter and the exhaust gas component parameter.

[0044] The respective range preferably extends from the minimum value to the maximum value and accordingly also includes a nominal value, which in particular corresponds to an average between the minimum and maximum values. The multiple values ​​can be stored discretely within the respective quantity or specified as ranges. In principle, the temperature quantity can contain any number of individual temperature values, for example, at least five, at least seven, or at least nine values. The torque quantity and the exhaust component quantity contain a corresponding number of values. The described procedure reliably eliminates measurement errors during optimization.

[0045] The invention further relates to a drive unit for a motor vehicle, in particular for carrying out the method according to the descriptions 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 is designed and configured to set an operating parameter on the drive unit to provide a drive torque.

[0046] The drive unit is also designed and configured to store, during warm-up operation of the drive unit, a torque parameter describing the drive torque as a function of a temperature parameter describing the temperature of the exhaust aftertreatment unit in a torque map, a parameter parameter describing the operating parameter as a function of the temperature parameter and the torque parameter in a parameter map, and an exhaust component parameter describing the quantity of an exhaust component in the exhaust gas as a function of the parameter parameter.

[0047] The drive unit is designed and configured to determine, after completion of the warm-up operation, within the framework of an optimization based on the torque map, the parameter map and the exhaust gas component map for the temperature parameter, the torque parameter that fulfills a torque condition by fulfilling an exhaust gas component parameter.

[0048] The advantages of such a drive system design and such a procedure have already been mentioned. Both the drive system and the method for operating it may be further developed as explained in this description, and reference is made to those explanations.

[0049] 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.

[0050] 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, can be used not only 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.

[0051] The invention is explained in more detail below with reference to the exemplary embodiments shown in the description, without limiting the invention. The only embodiment shown is... Fig. 1 A schematic representation of a flowchart, which explains a procedure for operating a drive unit for a motor vehicle.

[0052] The Fig. Figure 1 shows a flowchart illustrating, purely by way of example, a method for operating a drive unit for a motor vehicle. The drive unit has an exhaust-generating drive unit and an exhaust aftertreatment system for treating this exhaust gas. An operating parameter is set on the drive unit to provide drive torque.

[0053] The method described here employs an optimization model 1, which comprises an outer optimization loop 2 and an inner optimization loop 3. In the outer optimization loop 2, a first model 4 is executed, while in the inner optimization loop 3, a second model 5 and a third model 6 are executed. Each of the models 4, 5, and 6 operates based on a characteristic map 7, 8, and 9, respectively, where characteristic map 7 is a torque map, characteristic map 8 is a parameter map, and characteristic map 9 is an exhaust gas component map. In the torque map 7, a torque parameter 11 is defined as a function of a temperature parameter 10; in the parameter map 8, a parameter parameter 12 is defined as a function of both the temperature parameter 10 and the torque parameter 11; and in the exhaust gas component map 9, an exhaust gas component parameter 13 is defined as a function of parameter 12.

[0054] The temperature parameter 10 is composed of several temperatures and is therefore represented as an n-dimensional vector, where n corresponds to the number of temperature values. The torque parameter 11 is also represented as an n-dimensional vector and contains a torque value for each of the temperature values. The same applies to the parameter parameters 12 and 13, where one parameter 12 describes an air charge, in particular a relative air charge, and a second parameter 12 describes an ignition point. The exhaust gas component parameter 13 is also an n-dimensional vector, whereby in the embodiment shown here, two exhaust gas component parameters 13 are determined, namely for different exhaust gas components. For example, one of the exhaust gas components is nitrogen oxide (NOx). x ) and another of the exhaust gas components, carbon monoxide (CO).

[0055] The described optimization model 1 determines a drive torque which, at a given temperature of the exhaust aftertreatment system, fulfills a torque condition, in particular is at its maximum, while simultaneously the exhaust component size corresponding to the drive torque fulfills an exhaust component condition. The described procedure is used during the warm-up phase of the drive system and makes it possible to reliably determine the maximum possible drive torque based on a comparatively small number of measured values. REFERENCE MARK LIST: 1 Optimization model 2 outer optimization loop 3 inner optimization loop 4 1. Model 5 2nd model 6 3. Model 7 Torque map 8 parameter map 9 Exhaust component map 10 Temperature size 11 Torque size 12 Parameter size 13 Exhaust component size

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 operating parameter is set on the drive unit to provide a drive torque, characterized by that during a warm-up operation of the drive unit - in a torque map (7) a torque quantity (11) describing the drive torque as a function of a temperature quantity (10) describing a temperature of the exhaust aftertreatment device, - in a parameter map (8) a parameter quantity (12) describing the operating parameter as a function of the temperature quantity (10) and the torque quantity (11), and - in an exhaust gas component map (9) an exhaust gas component size (13) describing a quantity of an exhaust gas component in the exhaust gas as a function of the parameter size (12) stored and after completion of the warm-up operation, as part of an optimization based on the torque map (7), the parameter map (8) and the exhaust gas component map (9), the torque quantity (11) is determined for the temperature quantity (10) which fulfills a torque condition by fulfilling an exhaust gas component condition through the exhaust gas component quantity (13). [2] Method according to claim 1, characterized by , that the storage of the torque quantity (11) in the torque map (7), the storage of the parameter quantity (12) in the parameter map (8) and the storage of the exhaust gas component quantity (13) in the Exhaust gas component map (9) is carried out by means of a control unit of the drive system. [3] Method according to any one of the preceding claims, characterized by, that the torque quantity (11) fulfilling the torque condition is stored in a characteristic map as a function of the temperature quantity (10) and when the drive device is operated, the drive torque set on the drive unit is limited to a maximum torque which is read from the characteristic map as a function of the temperature of the exhaust aftertreatment device. [4] Method according to any one of the preceding claims, characterized by , that for optimization within a first model (4) the torque quantity (11) is read from the torque map (7) based on the temperature quantity (10), within a second model (5) the parameter quantity (12) is read from the parameter map (8) based on the temperature quantity (10) and the torque quantity (11), and within a third model (6) the exhaust gas component quantity (13) is read from the exhaust gas component map (9) based on the parameter quantity (12). [5] Method according to any one of the preceding claims, characterized by , that for optimization an outer optimization loop (2) is performed in which the torque quantity (11) is adjusted in the direction of a larger drive torque such that the exhaust component quantity (13) determined for the adjusted torque quantity on the basis of the parameter map (8) and the exhaust component map (9) satisfies the exhaust component condition. [6] Method according to any one of the preceding claims, characterized by , that within the outer optimization loop (2) an inner optimization loop (3) is executed in which the parameter size (12) is adjusted until the exhaust component size (13) read from the exhaust component map (9) meets the exhaust component condition and / or another exhaust component condition. [7] Method according to any one of the preceding claims, characterized by, that the adjustment of the parameter size (12) is carried out in such a way that the drive unit, when operated with the parameter size (12) describing the operating parameter, continues to generate the drive torque described by the torque size (11). [8] Method according to any one of the preceding claims, characterized by , that in the temperature parameter (10) several temperatures are stored, in the torque parameter (11) several torques and in the exhaust gas component parameter (13) several component quantities are stored. [9] 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 unit for aftertreatment of the exhaust gas and is designed and configured to set an operating parameter on the drive unit to provide a drive torque, characterized by that the drive unit is also designed and configured to operate during a warm-up phase of the drive unit - in a torque map (7) a torque quantity (11) describing the drive torque as a function of a temperature quantity (10) describing a temperature of the exhaust aftertreatment device, - in a parameter map (8) a parameter quantity (12) describing the operating parameter as a function of the temperature quantity (10) and the torque quantity (11), and - to store in an exhaust gas component map (9) an exhaust gas component size (13) describing a quantity of an exhaust gas component in the exhaust gas as a function of the parameter size (12) and, after completion of the warm-up operation, to determine, as part of an optimization, on the basis of the torque map (7), the parameter map (8) and the exhaust gas component map (9) for the temperature size (10) the torque size (11) which fulfills a torque condition by fulfilling an exhaust gas component condition through the exhaust gas component size (13). [10] Computer program product comprising instructions that cause the drive device according to claim 9 to execute the method according to one or more of claims 1 to 8.

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