Method for Operating a Catalytic Device, Catalytic Device, Internal Combustion Engine, Control Method for Controlling the Internal Combustion Engine, and Motor Vehicle
The method enhances catalytic converter efficiency by determining oxygen requirements based on lambda sensor data and characteristic maps, addressing inefficiencies and sensor failures to reduce untreated emissions.
Patent Information
- Authority / Receiving Office
- US · United States
- Patent Type
- Applications(United States)
- Current Assignee / Owner
- BAYERISCHE MOTOREN WERKE AG
- Filing Date
- 2024-02-09
- Publication Date
- 2026-07-30
AI Technical Summary
Existing catalytic converters for internal combustion engines are inefficient in treating exhaust gases, allowing untreated or slightly treated pollutants to escape, particularly when the lambda sensor breaks down, leading to unfavorable combustion ratios.
A method to determine an oxygen requirement value for the catalytic converter, using lambda sensor data and characteristic maps to adjust oxygen supply, allowing the converter to operate at optimal conversion rates without relying on post-catalytic sensor readings, and incorporating factors like operating modes and oxygen absorption capacity.
Improves the efficiency of catalytic converters by reducing untreated exhaust emissions, maintaining optimal operation even with sensor failures, and minimizing computational effort.
Smart Images
Figure US20260218644A1-D00000_ABST
Abstract
Description
BACKGROUND AND SUMMARY
[0001] The present disclosure relates to a method for operating a catalytic device, comprising a catalytic converter, for an internal combustion engine. Furthermore, the disclosure relates to a catalytic device which carries out the above-mentioned method. Moreover, the disclosure relates to an internal combustion engine, to which the catalytic converter of the catalytic device is connected on the exhaust gas side, and a control method for controlling such an internal combustion engine. In addition, the disclosure relates to a motor vehicle which comprises such an internal combustion engine and as a result the catalytic device.
[0002] The need exists to post-treat exhaust gas emitted by an internal combustion engine in operation thereof particularly efficiently in order to reduce pollutant emission into the environment in the best possible manner. Lambda-regulated catalytic converters are known for this purpose from the prior art. The highest possible conversion rate is achieved using the catalytic converter when it is operated in a narrow range around a combustion-stoichiometric combustion air ratio (λ=1), the so-called lambda window. For this purpose, it is helpful to know a current charge of the catalytic converter with oxygen in operation of the catalytic converter. In this context, DE 10 2004 009 615 A1 proposes a method for determining a current oxygen charge of a three-way catalytic converter of a lambda-regulated internal combustion engine, wherein a value for the current oxygen charge is calculated from a pre-catalytic converter lambda sensor signal and a measured air throughput by integration over time, which value is initialized in the event of signal breakthroughs of a post-catalytic converter lambda sensor. At the time of such a signal breakthrough of the post-catalytic converter lambda sensor, however, an unfavorable combustion air ratio has already existed, so that the exhaust gas resulting therefrom flows into the environment downstream of the catalytic converter untreated or only slightly treated, thus rich in pollutants.
[0003] An object of the disclosure is to improve an efficiency of a catalytic device for an internal combustion engine and to reduce an amount of an exhaust gas which emerges untreated or only slightly treated from the catalytic device.
[0004] Features, advantages, and possible embodiments which are described in the scope of the description for one of the subjects of the independent claims are to be viewed, spanning category and embodiment, at least analogously as features, advantages, and possible embodiments of the respective subject matter of the other independent claims and any possible combination of the subjects of the independent claims, possibly in conjunction with one or more of the dependent claims.
[0005] According to the disclosure, a method for operating a catalytic device, comprising a catalytic converter, for an internal combustion engine is proposed. With the aid of the method, an oxygen requirement value mO2 Bedarf is provided, which characterizes an oxygen supply to be supplied to the catalytic converter in order to set a target oxygen amount in the catalytic converter, at which the catalytic converter operates at the best possible conversion rate. Furthermore, the disclosure proposes a catalytic device, which comprises the catalytic converter and is configured to carry out the method for operating the catalytic device. In the intended installation position, the catalytic device forms a component of the internal combustion engine according to the disclosure, to which the catalytic converter is connected on the exhaust gas side. The internal combustion engine, in particular an engine control unit of the internal combustion engine, accepts the oxygen requirement value mO2 Bedarf determined by way of the method as a control signal. As a result, the internal combustion engine is controllable such that it provides an oxygen supply, by way of which the target oxygen amount is set in the catalytic converter. In the control method according to the disclosure for controlling the internal combustion engine, it is controlled such that it provides an oxygen supply, by way of which the target oxygen amount is set in the catalytic converter. Moreover, a motor vehicle which comprises the internal combustion engine and as a result the catalytic device is proposed according to the disclosure.
[0006] The method according to the disclosure for operating the catalytic device can be a computer-implemented method. The catalytic device is then configured to carry out the method. For this purpose, the catalytic device in particular comprises a catalytic converter control unit. Furthermore, the disclosure then proposes a first computer program, which, when its program commands are executed by the catalytic device, in particular its catalytic converter control unit, causes it to carry out the method for operating the catalytic device. Furthermore, the control method for controlling the internal combustion engine can be a computer-implemented method. In this case, the internal combustion engine is configured to carry out the method. For this purpose, the internal combustion engine in particular comprises the engine control unit. A second computer program is then proposed according to the disclosure, wherein when the program commands of the second computer program are executed by the internal combustion engine, in particular by its engine control unit, the internal combustion engine is controlled according to the control method for controlling the internal combustion engine. The disclosure moreover proposes a computer-readable storage medium, on which the first computer program and / or the second computer program is / are stored.
[0007] In the method according to the disclosure for operating the catalytic device, in a detection time interval, which has a predetermined duration of 10 ms (milliseconds), for example, an active operating mode of the internal combustion engine is detected in a step S1. It is thus detected, for example, whether the internal combustion engine is operated in an operating mode “dynamic load buildup”, an operating mode “reliable combustion”, or in an operating mode “consumption optimized”. A mixed operating mode comprising two or more operating modes is conceivable, as will be described in more detail hereinafter. Three load-speed characteristic maps associated with the corresponding operating mode are assigned to each possible operating mode, namely one for λ=1 (combustion stoichiometric), one for λ<1 (lean), and one for λ>1 (rich). The characteristic maps form, for example, a lambda range from λ=1.1 (inclusive) to λ=0.9 (inclusive). The content of the respective load-speed characteristic map is determined, for example, by way of test bench measurements and calculations of chemical reactions in the catalytic converter. The information comes from the characteristic maps as to whether oxygen is to be introduced into the catalytic converter or discharged from the catalytic converter in operation of the internal combustion engine.
[0008] For the further method, in a step S2, which can be carried out before, during, or after step S1, a lambda value λ is detected. To detect the lambda value, it is studied in particular in the scope of the method whether a measurement signal of a pre-catalytic converter lambda sensor arranged between the internal combustion engine and the catalytic converter in the exhaust system is considered to be reliable. If this is the case, the lambda value is measured by way of the precatalytic converter lambda sensor. In contrast, if it is found that the measurement signal of the precatalytic converter lambda sensor is to be assumed to be unreliable, for example, due to a defect, an inadequate operating temperature, etc., the lambda value is detected in that a target lambda value determined by way of an engine control unit of the internal combustion engine is adopted.
[0009] Based on the detected lambda value λ, in a step S3.1 of the method, a characteristic map weighting factor K is determined. In one possible embodiment of the method, the characteristic map weighting factor K is determined on the basis of a predetermined weighting characteristic curve, wherein the characteristic map weighting factor K is at least 0 and at most +1 (0≤K≥1). The weighting characteristic curve establishes a relationship between the detected lambda value λ and the characteristic map weighting factor K. In particular, the graph of the weighting characteristic curve is formed at least in one characteristic curve component of the weighting characteristic curve according to the following equation (see FIG. 2—graph 7a of the characteristic curve 7):K={0for λ<0.9(λ-0.9)·10for 0.9≤λ<1(1.1-λ)·10for 1≤λ≤1.10for λ>1.1
[0010] The weighting characteristic curve can be formed from at least one uneven or nonlinear characteristic curve component instead of linear characteristic curve components, for example, can comprise at least one part of a parabola graph, a hyperbola graph, a graph of a logarithmic function, a graph of an exponential function, a graph of a reciprocal value function, an oval (special case ellipse, special case circle), etc. Moreover, a weighting characteristic curve is conceivable which comprises both at least one linear characteristic curve component and at least one nonlinear or uneven characteristic curve component.
[0011] Furthermore, in a step S3.2, a first oxygen supply partial value sa is determined from the load-speed characteristic map assigned to the detected operating mode for λ=1. The first oxygen supply partial value sa characterizes an oxygen introduction into the catalytic converter or an oxygen discharge out of the catalytic converter depending on its sign. Moreover, the first oxygen supply partial value sa is offset by the characteristic map weighting factor K in step S3.2, multiplied in one possible embodiment of the method, from which a first characteristic map-weighted oxygen supply partial value Sa results:Sa=sa·K
[0012] In step S3.3 of the method, a second oxygen supply partial value sb is determined, specifically, if the detected lambda value λ is greater than 1, from the characteristic map assigned to the detected operating mode for λ>1 or, if the detected lambda value λ is less than 1, from the characteristic map assigned to the detected operating mode for λ<1. Analogously to the first oxygen supply partial value sa, the second oxygen supply partial value sb characterizes an oxygen introduction into the catalytic converter or an oxygen discharge out of the catalytic converter depending on its sign. If in step S2, for example, the lambda value λ=1.01 is detected, the second oxygen supply partial value sb is taken from the characteristic map for λ>1 (step S3.3.1). In contrast, if in step S2, for example, a lambda value λ=0.96 is detected, the second oxygen supply partial value sb is taken from the characteristic map for λ<1 (step S3.3.2). A further step S3.4 follows step S3.3.1 or S3.3.2, in which the second oxygen supply partial value sb is offset with the characteristic map weighting factor K, from which a second characteristic map-weighted oxygen supply partial value Sb results. In one possible embodiment of the method, the second oxygen supply partial value sb is multiplied by a difference, the minuend of which is 1 and the subtrahend of which is the characteristic map weighting factor K, in order to obtain the characteristic map-weighted oxygen supply partial value Sb:Sb=sb·(1-K)
[0013] If the lambda value in this case is precisely λ=1, the characteristic map weighting factor is K=1, due to which the second oxygen supply partial value is sb=0. In such a case, the first oxygen supply partial value sa is weighted at 100% and the second oxygen supply partial value sb at 0%. The characteristic map-weighted oxygen supply partial values Sa, Sb are added in a step S4 of the method to an actual oxygen supply value SZist of the detection time interval characterizing an actual oxygen supply of the catalytic converter. In this manner, an oxygen supply to the catalytic converter or an oxygen discharge out of the catalytic converter per detection time interval can be determined without the aid of a post-catalytic converter lambda sensor (which is also called a trim sensor). Catalytic reactions in a raw exhaust gas are advantageously also taken into consideration in this case, which behave differently at equal lambda value depending on the operating mode and / or operating point of the internal combustion engine.
[0014] In a method step S5, a total actual oxygen supply value SZist ges is detected, which comprises the actual oxygen supply value SZist, and in a method step S6, an actual oxygen amount value mO2 ist is detected, which characterizes an actual oxygen amount, for example, an actual oxygen mass, that is currently stored in the catalytic converter. The total actual oxygen supply value SZist ges thus comprises the actual oxygen supply value SZist for a pass of the method up to this point, in particular for a respective detection time interval; the determined actual oxygen supply value SZist is fed through, for example, in the form of the overall actual oxygen supply value SZist ges, to a further step of the method. As is described in more detail hereinafter, the overall actual oxygen supply value SZist ges can be added up in step S5 from two or more actual oxygen supply values SZist. The actual oxygen amount value mO2 ist is detected in step S6, for example, in that the overall actual oxygen supply value SZist ges is added to an oxygen amount starting value m0 of the catalytic converter.
[0015] In a step S7, based on the total actual oxygen supply value SZist ges, the actual oxygen amount value mO2 ist, and a target oxygen amount value mO2 soll, which characterizes the target oxygen amount, for example, a target oxygen mass, in the catalytic converter, at which the catalytic converter operates at the best possible conversion rate, the oxygen requirement value mO2 Bedarf is determined. This characterizes an oxygen supply which—depending on the sign of the oxygen requirement value mO2 Bedarf—is to be supplied to the catalytic converter or discharged out of the catalytic converter in order to set the target oxygen amount in the catalytic converter, at which the catalytic converter operates at the best possible conversion rate. If the target oxygen amount is thus present in the catalytic converter, it will be operated at a combustion-stoichiometric combustion air ratio (λ=1), the so-called lambda window. In a step S8, the oxygen requirement value mO2 Bedarf is provided, for example, delivered to another control unit and / or output in another way. In particular, the oxygen requirement value mO2 Bedarf is provided or delivered to the engine control unit of the internal combustion engine.
[0016] By way of the method for operating the catalytic device, the efficiency of a catalytic device for an internal combustion engine is improved, so that the internal combustion engine or the motor vehicle comprising the internal combustion engine are operable with particularly low emissions. This is because an amount of an exhaust gas which emerges untreated or only slightly treated from the catalytic device is reduced, wherein particularly little computing power has to be applied by participating computers or control units, etc. Due to the method, determining an oxygen requirement in the catalytic converter is no longer accompanied by measuring a lambda value downstream from the catalytic converter (trim sensor deflection), but rather is determined on the basis of the method described here without a trim sensor deflection occurring frequently due to exhaust gas which is slightly treated flowing out of the catalytic converter.
[0017] In a further possible embodiment of the method, steps S1, S2 are carried out as described above. In step S3.1, a characteristic map weighting factor K is then determined based on the detected lambda value λ. In particular, the characteristic map weighting factor K is determined on the basis of a predetermined weighting characteristic curve, wherein the characteristic map weighting factor K is at least −1 and at most +1 here (−1≤K≥+1). The weighting characteristic curve is then in particular mapped according to the following equation (see FIG. 2—graph 7c of characteristic curve 7):K={-1for λ<0.9(λ-1)·10for 0.9≤λ<1.11for λ>1.1
[0018] The first oxygen supply partial value sa is multiplied in step S3.2 according to this embodiment of the method by a difference, the minuend of which is 1 and the subtrahend of which is the absolute value of the characteristic map weighting factor K, from which the first characteristic map-weighted oxygen supply partial value Sa results:Sa=sa·(1-<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[LeftBracketingBar]"< / annotation>< / semantics>K<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[RightBracketingBar]"< / annotation>< / semantics>)
[0019] Steps S3.3, S3.3.1, and S3.3.2 then follow as described above. After step S3.3.1 or S3.3.2, step S3.4 then takes place, in which according to this design of the method the second oxygen supply partial value sb is multiplied by the absolute value of the characteristic map weighting factor K, from which the second characteristic map-weighted oxygen supply partial value Sb results:Sb=sb·<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[LeftBracketingBar]"< / annotation>< / semantics>K<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[RightBracketingBar]"< / annotation>< / semantics>
[0020] If the lambda value is precisely λ=1 in this case, the characteristic map weighting factor is K=0, due to which the second oxygen supply partial value is sb=0. Above-described steps S4 to S8 follow this.
[0021] According to a possible further design of the method, at least steps S1 to S8 are repeated for a further detection time interval or multiple detection time intervals, wherein in respective step S5, the overall actual oxygen supply value SZist ges is determined in that the actual oxygen supply values SZist of the detection time intervals are integrated over an overall duration of the detection time intervals to form the overall actual oxygen supply value SZist ges. In this way, the information about how much oxygen the catalytic converter is charged with over time or during its operation is provided. Furthermore, in step S6, the actual oxygen amount value mO2 ist is then detected or refined in that the overall actual oxygen supply value SZist ges of the current pass is added to an actual oxygen amount value mO2 ist of a prior pass of method steps S1 to S6. It is thus determined how much oxygen the catalytic converter is charged with in relation to the time. The oxygen requirement value mO2 Bedarf is thus continuously adapted and provided during the operation of the catalytic converter. Further steps of the method, in particular steps of further designs of the method described herein, can be repeated for the further detection time interval or for the further detection time intervals.
[0022] In one possible refinement, it is provided that before an initial determination of the oxygen requirement value mO2 Bedarf, in particular before an initial determination of the oxygen amount value mO2 ist, a lambda deflection is detected by way of a post-catalytic converter lambda sensor (which can also be referred to as a trim sensor) arranged on the outflow side after the catalytic converter in the exhaust system, which deflection characterizes the presence of a defined oxygen amount in the catalytic converter. The deflection of the post-catalytic converter lambda sensor characterizes that a defined amount of oxygen is present in the catalytic converter. If the post-catalytic converter lambda sensor supplies a deflection in the direction of rich mixture (λ<1), it is assumed that particularly little oxygen is present in the catalytic converter; an oxygen amount starting value m0 is assumed which characterizes an oxygen-poor gas mixture in the catalytic converter. If the post-catalytic converter lambda sensor deflects in the direction of a lean mixture (λ>1), this means that a particularly large amount of oxygen is present in the catalytic converter; an oxygen amount starting value m0 is then assumed which characterizes an oxygen-rich gas mixture in the catalytic converter. In step S6, the actual oxygen amount value mO2 ist of the catalytic converter is then detected in that the overall actual oxygen supply value SZist ges and an oxygen amount starting value m0 characterizing the defined oxygen amount are added. If steps of the method are repeated, it is provided in particular that the oxygen amount starting value m0 is only detected by way of a single initial deflection of the post-catalytic converter lambda sensor. In normal operation, in which the internal combustion engine coupled with the catalytic device is started by way of a cold start, the post-catalytic converter lambda sensor typically deflects for the first time after 1 to 2 seconds. For possible repetitions of steps of the method in a disturbance-free normal operation of the catalytic converter, the use of the post-catalytic converter lambda sensor does not take place; it is then only used as a redundant measuring device, for example, for identifying a disturbance of the operation of the catalytic device. This refinement has the advantage that a defined starting state of the catalytic converter is detected, so that the method runs particularly efficiently. This is because estimating a current oxygen amount in the catalytic converter for the initial determination of the oxygen amount value mO2 ist can be omitted. Furthermore, it can be provided that the initial deflection of the post-catalytic converter lambda sensor is used as a starting signal for the method, wherein the method is not executed until the initial deflection of the post-catalytic converter lambda sensor is detected.
[0023] In a further possible embodiment of the method, one further active operating mode is or two or more active operating modes are detected. It is thus detected that the internal combustion engine is simultaneously operated in one or more of the operating modes “dynamic load buildup”, “reliable combustion”, “consumption optimized”, and / or other / further possible operating modes. Each of the operating modes results in a different composition of the raw exhaust gas. This is because in the case of “dynamic load buildup” the inlet valves are opened in relation to a combustion chamber of the internal combustion engine, while the outlet valves are still open, so that a part of the intake air flows out of the combustion chamber via outlet valves, so that this intake air part therefore does not participate in combustion in the combustion chamber. In “reliable combustion”, the internal combustion engine is controlled such that—in particular during cold start or with (still) cold combustion chamber inner walls—ignition of the fuel-air mixture located in the combustion chamber is reliably ensured. In “consumption optimized”, the internal combustion engine is controlled for the most fuel-efficient operation possible.
[0024] If the internal combustion engine is operated in a mixed operating mode, which comprises two or more active operating modes, in the method, steps S2-S4 are carried out separately and in parallel for each of the detected active operating modes. Moreover, in particular before step S5, it is detected which percentage operating mode proportion B1, B2, . . . , Bn the respective operating mode has in a current overall operation or in the currently active mixed operating mode of the internal combustion engine. The following applies here:∑i=1nBi=1
[0025] The respective actual oxygen supply value SZist is then multiplied by the associated one of the percentage operating mode proportions B1, B2, . . . , Bn, by which operating mode proportion-weighted actual oxygen supply values SZist B1, SZist B2, . . . , SZist Bn are generated:for the first operating mode: SZist B1=B1·SZist,for the second operating mode: SZist B2=B2·SZist,for each further operating mode: SZist B n=Bn·SZist.
[0026] In step S5, the overall actual oxygen supply value SZist ges is detected in that the operating mode proportion-weighted actual oxygen supply values SZist B1, SZist B2, . . . , SZist Bn are added:SZist ges=∑i=1n SZist Bi
[0027] In this way, the oxygen requirement value mO2 Bedarf is determined particularly accurately, since the composition of the raw exhaust gas is taken into consideration particularly accurately depending on the participating operating modes.
[0028] According to one possible refinement, an operating mode characteristic curve, which was deliberately created for the purpose of controlling the catalytic device, is used to detect the respective percentage operating mode proportion B1, B2, . . . , Bn. In particular, the operating mode characteristic curve is not provided by the engine control unit of the internal combustion engine, the motor vehicle, or another catalytic-device-external control unit. This is because it was determined in internal studies that in order to achieve a particularly advantageous result by way of the method described herein, the operating modes which participate in the overall operation are to be weighted for the others differently than a controller of the internal combustion engine does. The operating mode weighting determined or set by way of the controller of the internal combustion engine is therefore usable for the method, however, for particularly efficient and in particular agile setting of the target oxygen amount in the catalytic converter, it has proven to be more expedient to use the operating mode characteristic curve developed separately for the method.
[0029] It is proposed according to a further possible embodiment of the method that-if a lambda value is detected in step S2 which lies outside the lambda value ranges stored in the load-speed characteristic maps—an extrapolation factor E is determined, in particular from an extrapolation characteristic curve developed especially for the method. Moreover, in steps S3.2 and S3.3, the unweighted oxygen supply partial value sa, sb is determined from the respective characteristic map which corresponds to a closest one of the lambda values stored in the characteristic map. The extrapolation factor E and the respective oxygen supply partial value sa, sb are then multiplied by one another before step S4, i.e. before the addition of the oxygen supply partial values Sa, Sb, in particular before the characteristic map weighting of the oxygen supply partial value sa, sb. This means that the oxygen supply partial values sa, sb are calculated with the aid of the extrapolation factor E if a lambda value is detected which is not stored in the characteristic maps. This is the case, for example, if the load-speed characteristic maps do not cover lambda values λ<0.9 and / or λ>1.1 and a lambda value outside these limits is detected. Other characteristic maps which cover a larger lambda range are conceivable, of course. On the basis of the extrapolation factor E, it is possible particularly easily or with little effort to set the target oxygen amount in the catalytic converter even if a lambda value is detected which lies outside the lambda value ranges covered by the characteristic maps.
[0030] Whether or not the catalytic converter can absorb oxygen at a time depends, among other things, on the amount of oxygen which is already present at the same time in the catalytic converter. To regulate the oxygen supply to the catalytic converters such that the target oxygen amount results as quickly and efficiently as possible in the catalytic converter, it is provided according to a further possible embodiment of the method that an absorption correction factor M is determined based on an oxygen absorption capacity of the catalytic converter. The oxygen absorption capacity of the catalytic converter is in particular determined here based on an exhaust gas mass flow and the actual oxygen amount in the catalytic converter on the basis of an absorption capacity characteristic map developed especially for the method. The following applies for the absorption correction factor M,
[0031] if the catalytic converter is fully capable of oxygen absorption: M≥1,
[0032] if the catalytic converter is partially capable of oxygen absorption: 0<M≤1,
[0033] if the catalytic converter is not capable of oxygen absorption at all: M=0.
[0034] The absorption correction factor M is multiplied by the overall actual oxygen supply value SZist ges, so that the overall actual oxygen supply value SZist ges is adapted to the current oxygen absorption capacity of the catalytic converter. In step S8, the oxygen requirement value mO2 Bedarf is then output or provided, in which the adapted overall actual oxygen supply value SZist ges is taken into consideration. In this way, both an oxygen overload and an oxygen under supply of the catalytic converter are avoided particularly efficiently.
[0035] In a further possible embodiment of the method, it is taken into consideration whether the internal combustion engine is entirely or partially operated in overrun operation. For this purpose, an overrun operation combustion chamber number Z and a combustion chamber-individual overrun operation oxygen supply value SZZ are determined. The overrun operation combustion chamber number Z characterizes a number of combustion chambers of the internal combustion engine which are operated in an unfired (ignition-free) overrun operation. The combustion chamber-individual overrun operation oxygen supply value SZZ characterizes an oxygen amount which is applied to the catalytic converter from precisely one unfired combustion chamber of the internal combustion engine. The overrun operation oxygen supply value SZZ is determined on the basis of an air mass flow which is fed through an unfired combustion chamber in overrun operation. It is furthermore evaluated in this embodiment of the method how the overrun operation combustion chamber number Z and a total number ZVKM of the combustion chambers of the internal combustion engine are related to one another. If it is detected here that the overrun operation combustion chamber number Z is less than the total number ZVKM of the combustion chambers, a combustion chamber correction factor ZK is calculated:ZK=ZZVKM
[0036] The combustion chamber correction factor ZK and the actual oxygen supply value SZist are then multiplied together, from which an overrun operation-corrected actual oxygen supply value SZist Z korr results:SZist Z korr=SZist·ZK
[0037] Moreover, the combustion chamber-individual overrun operation oxygen supply value SZZ and the overrun operation combustion chamber number Z are multiplied together, from which an actual combustion chamber oxygen supply value SZZ ist results:SZZ ist=SZZ·Z
[0038] After this, in step S5, the overrun operation-corrected actual oxygen supply value SZist Z korr and the actual combustion chamber oxygen supply value SZist are added to form the overall actual oxygen supply value SZist ges.SZist ges=SZZ ist+SZist Z korr
[0039] In contrast, if it is detected that the overrun operation combustion chamber number Z and the total number ZVKM of the combustion chambers are equal, the overrun operation oxygen supply value SZZ and the overrun operation combustion chamber number Z are multiplied together, from which the overall actual oxygen supply value SZist ges results:SZZ ist=SZZ·Z
[0040] The catalytic converter receives more oxygen from a combustion chamber operated in overrun operation than from a combustion chamber operated in a fired manner. Therefore, the amount of oxygen which is applied to the catalytic converter in operation of the internal combustion engine increases with rising overrun operation combustion chamber number Z. In that it is taken into consideration whether one or more of the combustion chambers is / are operated in overrun operation, the target oxygen amount is set even more efficiently in the catalytic converter.
[0041] Further features of the disclosure can result from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description and the features and combinations of features hereinafter in the description of the figures and / or solely shown in the figures are usable not only in the respective specified combination, but also in other combinations or alone, without departing from the scope of the disclosure.BRIEF DESCRIPTION OF DRAWINGS
[0042] FIG. 1 shows a flow chart to illustrate a method for operating a catalytic device comprising a catalytic converter for an internal combustion engine, wherein FIG. 1 comprises FIG. 1a and FIG. 1b;
[0043] FIG. 2 shows a weighting characteristic curve used in the method; and,
[0044] FIG. 3 shows a regulation model characterizing the method, which was generated by way of modeling software for modeling physical systems, in the present case Matlab Simulink, wherein FIG. 3 comprises FIGS. 3a, 3b, 3c, and 3d. DETAILED DESCRIPTION OF DRAWINGS
[0045] A method for operating a catalytic device comprising a catalytic converter for an internal combustion engine, a catalytic device configured to carry out the method, an internal combustion engine comprising the catalytic device, a control method for controlling the internal combustion engine, and a motor vehicle comprising the internal combustion engine are explained in a common description hereinafter. Identical and functionally-identical elements are provided with identical reference signs here in the figures. Catalytic device, internal combustion engine, the control methods thereof, and the motor vehicle are not shown in the figures.
[0046] With the aid of the method, an oxygen requirement value mO2 Bedarf is provided which characterizes an oxygen supply to be supplied to the catalytic converter in order to set a target oxygen amount in the catalytic converter particularly efficiently, in order to operate it as close as possible to a combustion-stoichiometric lambda value. The catalytic device forms, in the intended installation location, a component of the internal combustion engine according to the disclosure, to which the catalytic converter is connected on the exhaust gas side. The internal combustion engine, in particular a motor control unit of the internal combustion engine, accepts the oxygen requirement value determined by way of the method as a control signal, so that the internal combustion engine is controlled by way of the control method so that it provides an oxygen supply by way of which the target oxygen amount is set in the catalytic converter. The control unit may comprise a motor control unit, or an engine control unit, and / or a processor configured to execute software, instructions, and / or logic stored on a memory, such as the control method disclosed herein.
[0047] In a step S1 of the method for operating the catalytic device, an active operating mode of the internal combustion engine is detected. In the present case, the internal combustion engine is operated in a mixed operating mode, which means that in step S1, two or more simultaneously active but different operating modes (identified in FIG. 3b by the reference signs 1, 2, 3) of the internal combustion engine are detected, which overlap or are superimposed on one another. In other words, the internal combustion engine is operated in the present example partially in a first operating mode, partially in a second operating mode, and partially in at least one further operating mode at the same time. Moreover, it is detected in the method in the present case which percentage operating mode proportion B1, B2, . . . , Bn the respective operating mode has in a current overall operation or in the currently active mixed operating mode of the internal combustion engine. This can be read, for example, from an engine control unit of the internal combustion engine. However, it is provided here in the example that the respective percentage operating mode proportion B1, B2, . . . , Bn is taken from an operating mode characteristic curve developed especially for the method for operating the catalytic device. Three operating mode-associated load-speed characteristic maps are specified in each case for each operating mode, namely one for λ=1, one for λ<1, and one for λ>1.
[0048] In step S2, a lambda value λ is detected. For example—in particular if it is determined in the method that a measurement signal of a pre-catalytic converter lambda sensor is implausible or unreliable—a target lambda value is used as the lambda value λ, which is provided, for example, by way of the engine control unit of the internal combustion engine. In contrast, if it is established in the method that the measurement signal of the pre-catalytic converter lambda sensor is plausible, the lambda value λ is measured by way of the pre-catalytic converter lambda sensor.
[0049] S3.1 designates a step of the method in which, based on the detected lambda value λ and on the basis of a predetermined weighting characteristic curve 7 (see FIG. 2), a characteristic map weighting factor K is determined, for which the following applies: 0≤K≥+1. The graph 7a of the weighting characteristic curve 7 results in the present case from the equationSZist ges=SZZ ist+SZist Z korr
[0050] FIG. 2 shows further possible weighting characteristic curves 7. A graph of a weighting characteristic curve 7 is designated by 7b, which is formed from uneven or nonlinear characteristic curve components instead of linear characteristic curve components, for example, according to a parabolic function, a logarithmic function, an exponential function, a reciprocal value function, etc. Moreover, weighting characteristic curves are conceivable which comprise both at least one linear characteristic curve component and at least one nonlinear or uneven characteristic curve component.
[0051] In a step S3.2 of the method, a respective first oxygen supply partial value sa is determined for each operating mode participating in the overall operation of the internal combustion engine from the load-speed characteristic map assigned to the corresponding operating mode for λ=1. If three operating modes are thus participating in the overall operation of the internal combustion engine, a first oxygen supply partial value sa is therefore determined in each case from three load-speed characteristic maps for λ=1, overall three first oxygen supply partial values sa. The respective first oxygen supply partial value sa is then offset in step S3.2 with the correction factor K, from which a first characteristic map-weighted oxygen supply partial value Sa results:SZist ges=SZZ ·Z
[0052] If the lambda value λ detected in step S2 is greater than 1, in a step S3.3.1, a second oxygen supply partial value sb is determined from the characteristic map predetermined for the detected operating mode for λ>1. In contrast, if the lambda value λ detected in step S2 is less than 1, instead of step S3.3.1, a step S3.3.2 is carried out, in which the second oxygen supply partial value sb is determined from the characteristic map predetermined for the detected operating mode for λ<1.
[0053] In a step S3.4, the second oxygen supply partial value sb is multiplied by the characteristic map weighting factor K, from which a second characteristic map-weighted oxygen supply partial value Sb results:Sb=sb·(1-K)
[0054] If the detected lambda value is precisely λ=1, the characteristic map weighting factor is K=1, due to which the second oxygen supply partial value is sb=0. In such a case, the first oxygen supply partial value sa is weighted with 1 or 100% and the second oxygen supply partial value sb with 0 or 0%.
[0055] For the case that in step S2 a lambda value λ is detected which lies outside the lambda value ranges stored in the load-speed characteristic maps, furthermore an extrapolation factor E is determined in the method. If in step S2 such a lambda value λ not covered by the lambda value ranges of the load-speed characteristic maps is detected, an oxygen supply partial value sa, sb determined from the corresponding characteristic map, which corresponds to a closest one of the lambda values (λ) stored in the characteristic map, is multiplied by the extrapolation factor and thus used for the further method. The use of the extrapolation factor E is identified in FIG. 3c by the reference sign 4.
[0056] The characteristic map-weighted oxygen supply partial values Sa, Sb are added in a step S4 of the method to an actual oxygen supply value SZist. One example of such a characteristic map weighting procedure, in which the second oxygen supply value sb originates from the characteristic map for λ>1, is shown in FIG. 3a. The steps of the method described up to this point are carried out simultaneously and separately for each of the operating modes participating in the overall operation. Then, for example, in respective step S4, the actual oxygen supply value SZist associated with the corresponding operating mode is multiplied by the associated one of the percentage operating mode proportions B1, B2, . . . , Bn, by which operating mode proportion-weighted actual oxygen supply values SZist B1, SZist B2, . . . , SZist Bn are generated, which are incorporated in a step S5 in an overall actual oxygen supply value SZist ges:for the first operating mode: SZist B1=B1·SZist,for the second operating mode: SZist B2=B2·SZist,for each further operating mode: SZist Bn=Bn·SZist.
[0057] In the design of the method described here by way of example, moreover an overrun operation combustion chamber number Z is determined, which characterizes a number of combustion chambers of the internal combustion engine which are operated in an unfired (ignition-free) overrun operation. If precisely four combustion chambers or cylinders of the internal combustion engine are operated in overrun operation, the overrun operation combustion chamber number is Z=4. Moreover, in the present case a combustion chamber-individual overrun operation oxygen supply value SZZ is determined, which characterizes an oxygen amount fed to the catalytic converter from precisely one unfired combustion chamber of the internal combustion engine. The overrun operation oxygen supply value SZZ is determined in the present case on the basis of an air mass flow which is fed through the corresponding unfired combustion chamber in overrun operation. If it is furthermore detected in the method here in the example that the overrun operation combustion chamber number Z is less than the total number ZVKM of the combustion chambers, a combustion chamber correction factor ZK is calculated:ZK=ZZVKM
[0058] If the internal combustion engine set forth here as an example thus has a total of six combustion chambers / cylinders, the combustion chamber correction factor is ZK=0.6. The combustion chamber correction factor ZK and the actual oxygen supply value SZist are then multiplied together, from which an overrun operation-corrected actual oxygen supply value SZist Z korr results:SZist Z korr=SZist·ZK
[0059] The overrun operation-corrected actual oxygen supply value SZist Z korr is in the present example two thirds of the actual oxygen supply value SZist originating from the completely fired operation of the internal combustion engine. The combustion chamber-individual overrun operation oxygen supply value SZZ and the overrun operation combustion chamber number Z are multiplied together, from which an actual combustion chamber oxygen supply value SZZ ist results:SZZ ist=SZZ·Z
[0060] After this, in step S5, the overrun operation-corrected actual oxygen supply value SZist Z korr and the actual combustion chamber oxygen supply value SZZ ist are added to form the overall actual oxygen supply value SZist ges:SZist ges=SZZ ist+SZist Z korr
[0061] In contrast, if it is detected that the overrun operation combustion chamber number Z and the total number ZVKM of the combustion chambers are equal, the overrun operation oxygen supply value SZZ and the overrun operation combustion chamber number Z are multiplied together, from which in step S5 the overall actual oxygen supply value SZist ges results:SZist ges=SZZ ·Z
[0062] The component of the method in which the overrun shut off is incorporated in the determination of the oxygen requirement value mO2 Bedarf is shown in FIG. 3d in the area of the reference sign 5.
[0063] In a step S6, an actual oxygen amount value mO2 ist is detected, which characterizes an actual oxygen amount, here an actual oxygen mass, that is currently stored in the catalytic converter. For this purpose, the overall actual oxygen supply value SZist ges is added, for example, to an oxygen amount starting value m0 of the catalytic converter. In the present case, it is provided that before an initial determination of the oxygen requirement value mO2 Bedarf, in particular before an initial determination of the oxygen amount value mO2 ist, a lambda deflection which characterizes the presence of a defined oxygen amount in the catalytic converter, is detected by way of a post-catalytic converter lambda sensor (which can also be referred to as a trim sensor) arranged on the outflow side after the catalytic converter in the exhaust system. In step S6, the actual oxygen amount value mO2 ist of the catalytic converter is then detected in that the overall actual oxygen supply value SZist ges and an oxygen amount starting value m0 characterizing the defined oxygen amount are added.
[0064] In a step S7, based on the overall actual oxygen supply value SZist ges, the actual oxygen amount value mO2 ist, and a target oxygen amount value mO2 soll, which characterizes the target oxygen amount, for example, a target oxygen mass, in the catalytic converter, at which the catalytic converter operates at the best possible conversion rate, the oxygen requirement value mO2 Bedarf is determined. This characterizes an oxygen supply which—depending on the sign of the oxygen requirement value mO2 Bedarf—is to be supplied to the catalytic converter or discharged out of the catalytic converter in order to set the target oxygen amount in the catalytic converter, at which the catalytic converter operates at the best possible conversion rate.
[0065] It is moreover provided in the present example that an absorption correction factor M is determined based on an oxygen absorption capacity of the catalytic converter. The oxygen absorption capacity of the catalytic converter is determined here based on an exhaust gas mass flow and the actual oxygen amount in the catalytic converter on the basis of an absorption capacity characteristic map developed especially for the method. The following applies for the absorption correction factor M,
[0066] if the catalytic converter is fully capable of oxygen absorption: M≥1,
[0067] if the catalytic converter is partially capable of oxygen absorption: 0<M≤1,
[0068] if the catalytic converter is not capable of oxygen absorption at all: M=0.
[0069] The absorption correction factor M is multiplied by the overall actual oxygen supply value SZist ges, so that the overall actual oxygen supply value SZist ges is scaled according to the current oxygen absorption capacity of the catalytic converter. A possible regulation implementation for the determination of the absorption correction factor M is shown in the area of the reference sign 6 in FIG. 3c.
[0070] In a step S8, the oxygen requirement value mO2 Bedarf is provided, delivered here to another control unit, in the present case the engine control unit of the internal combustion engine.
[0071] Up to this point, steps of the method have been described by way of example for one detection time interval in order to arrive at the oxygen requirement value mO2 Bedarf of that detection time interval. Steps S1 to S8—in particular including one or more of the described substeps or secondary steps—are repeated at least once in the present case, in particular as long as the catalytic device is operated in an activated operating state. In this case, in respective step S5, the overall actual oxygen supply value SZist ges is determined recursively in that the actual oxygen supply values SZist of the detection time intervals are integrated or added up over an overall duration of the detection time intervals to form the overall actual oxygen supply value SZist ges. Moreover, in step S6, the actual oxygen amount value mO2 ist is recursively refined in that the overall actual oxygen supply value SZist ges of the current pass is added to an actual oxygen amount value mO2 ist of a prior pass of the method steps. The oxygen requirement value mO2 Bedarf is continuously adapted and provided as a result during the operation of the catalytic converter.
[0072] If steps of the method are repeated, it is provided in particular that the oxygen amount starting value m0 is only detected by way of a single, initial deflection of the post-catalytic converter lambda sensor. It can furthermore be provided that the initial deflection of the post-catalytic converter lambda sensor is used as a starting signal for the method, wherein the method is not executed until the first deflection of the post-catalytic converter lambda sensor is detected.
[0073] For the description of an alternative exemplary embodiment of the method, only differences from the possible exemplary embodiment of the method described up to this point are discussed hereinafter. If not explicitly indicated otherwise, the description of the possible exemplary embodiment described up to this point applies to the alternative exemplary embodiment. In step S3.1, a characteristic map weighting factor (K) is determined based on the detected lambda value λ on the basis of the predetermined weighting characteristic curve 7, for which the following applies: −1≤K>+1. The graph 7c of the weighting characteristic curve 7 then results, for example, from the equation:K={-1for λ<0.9(λ-1)·10for 0.9≤λ≤1.11for λ>1.1
[0074] In step S3.2, the determined first oxygen supply partial value sa is multiplied by a difference, the minuend of which is 1 and the subtrahend of which is the absolute value of the characteristic map weighting factor K, from which the first characteristic map-weighted oxygen supply partial value Sa results:Sa=sa·(1-<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[LeftBracketingBar]"< / annotation>< / semantics>K<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[RightBracketingBar]"< / annotation>< / semantics>)
[0075] In step S3.4, the second oxygen supply partial value sb is multiplied by the absolute value of the characteristic map weighting factor K, from which the second characteristic map-weighted oxygen supply partial value Sb results:Sb=sb·<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[LeftBracketingBar]"< / annotation>< / semantics>K<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[RightBracketingBar]"< / annotation>< / semantics>
[0076] Steps S1, S2, S3.3, S3.3.1, S3.3.2, and S4-S8 and possible secondary steps or substeps are carried out in the alternative exemplary embodiment as described above.
[0077] A respective possibility is shown by the method for operating the catalytic device, by the catalytic device, by the internal combustion engine, by the control method, and by the motor vehicle for how an efficiency of a catalytic device can be improved. An amount of an exhaust gas which emerges untreated or only slightly treated from the catalytic device is significantly reduced in comparison to the prior art.LIST OF REFERENCE SIGNSB1, B2, . . . , Bn operating mode proportion
[0079] E extrapolation factor
[0080] K characteristic map weighting factor
[0081] M absorption correction factor
[0082] m0 oxygen amount starting value
[0083] mO2 Bedarf oxygen requirement value
[0084] mO2 ist actual oxygen amount value
[0085] mO2 soll target oxygen amount value
[0086] Sa first characteristic map-weighted oxygen supply partial value
[0087] sa first oxygen supply partial value (unweighted)
[0088] Sb second characteristic map-weighted oxygen supply partial value
[0089] sb second oxygen supply partial value (unweighted)
[0090] SZist B1, . . . , SZist Bn operating mode-weighted actual oxygen supply value
[0091] SZist ges overall actual oxygen supply value
[0092] SZist Z korr overrun operation-corrected actual oxygen supply value
[0093] SZist actual oxygen supply value
[0094] SZZ ist actual combustion chamber oxygen supply value
[0095] SZZ combustion chamber-individual overrun operation oxygen supply value to load change time
[0096] Z overrun operation combustion chamber number
[0097] ZK combustion chamber correction factor
[0098] ZVKM total number of the combustion chambers of the internal combustion engine
[0099] Δt0-1 gas runtime
[0100] Δt1-2 sensor reaction time
[0101] λ detected lambda value
[0102] 1, 2, 3 operating mode
[0103] 4 use of the extrapolation factor
[0104] 5 determination of the overrun shut off
Claims
1. -15. (canceled)16. A method for operating a catalytic device comprising a catalytic converter for an internal combustion engine, wherein in a detection time interval, the method comprises the steps(S) of:S1 an active operating mode of the internal combustion engine is detected,S2 a lambda value (λ) is detected, and based thereon:S3.1 a characteristic map weighting factor is determined,S3.2 a first oxygen supply partial value is determined from a characteristic map predetermined for the detected operating mode for λ=1 and offset with the characteristic map weighting factor, from which a first characteristic map-weighted oxygen supply partial value results,S3.3 a second oxygen supply partial value (sb) is determined, specifically:S3.3.1 if the lambda value (λ) is greater than 1, from a characteristic map predetermined for the detected operating mode for λ>1, or,S3.3.2 if the lambda value (λ) is less than 1, from a characteristic map predetermined for the detected operating mode for λ<1,S3.4 the second oxygen supply partial value (sb) is offset with the characteristic map weighting factor, from which a second characteristic map-weighted oxygen supply partial value results,S4 the characteristic map-weighted oxygen supply partial values are added to an actual oxygen supply value characterizing an actual oxygen supply of the catalytic converter,S5 an overall actual oxygen supply value comprising the actual oxygen supply value is detected,S6 an actual oxygen amount value is detected, which characterizes an actual oxygen amount currently stored in the catalytic converter,S7 based on the overall actual oxygen supply value, the actual oxygen amount value, and a target oxygen amount value, which characterizes a target oxygen amount in the catalytic converter at which the catalytic converter operates at the best possible conversion rate, an oxygen requirement value is determined, which characterizes an oxygen supply to be supplied to the catalytic converter in order to set the target oxygen amount in the catalytic converter, andS8 the oxygen requirement value of the detection time interval is provided.
17. The method according to claim 16, wherein:in step S3.1, the characteristic map weighting factor is determined, which is at least 0 and at most +1,in step S3.2, the determined first oxygen supply partial value is multiplied by the characteristic map weighting factor, from which the first characteristic map-weighted oxygen supply partial value results, andin step S3.4, the second oxygen supply partial value is multiplied by a difference, the minuend of which is 1 and the subtrahend of which is the characteristic map weighting factor, from which the second characteristic map-weighted oxygen supply partial value results.
18. The method according to claim 17, wherein:the characteristic map weighting factor is determined on the basis of a predetermined weighting characteristic curve, wherein at least one characteristic curve component of the weighting characteristic curve is formed according to the following equation:K={0for λ<0.9(λ-0.9)·10for 0.9≤λ≤1(1.1-λ)·10for 1≤λ≤1.10for λ>1.
119. The method according to claim 16, wherein:in step S3.1, the characteristic map weighting factor is determined, which is at least −1 and at most +1,in step S3.2, the determined first oxygen supply partial value is multiplied by a difference, the minuend of which is 1 and the subtrahend of which is the absolute value of the characteristic map weighting factor, from which the first characteristic map-weighted oxygen supply partial value results, andin step S3.4, the second oxygen supply partial value is multiplied by the absolute value of the characteristic map weighting factor, from which the second characteristic map-weighted oxygen supply partial value results.
20. The method according to claim 19, wherein:the characteristic map weighting factor is determined on the basis of a predetermined weighting characteristic curve, wherein at least one characteristic curve component of the weighting characteristic curve is formed according to the following equation:K={-1for λ<0.9(λ-1)·10for 0.9≤λ≤1.11for λ>1.
121. The method according to claim 16, wherein:steps S1-S8 are repeated for a further detection time interval, wherein in respective step S5, the actual oxygen supply values are integrated over a total duration of the detection time intervals to form the overall actual oxygen supply value, and in respective step, a current actual oxygen amount value is detected in that the actual oxygen amount values are added up over the total duration.
22. The method according to claim 20, wherein:before an initial determination of the oxygen requirement value, a lambda deflection is detected by way of a post-catalytic converter lambda sensor arranged on the outflow side after the catalytic converter in the exhaust system, which deflection characterizes the presence of a defined oxygen amount in the catalytic converter, and the actual oxygen amount value of the catalytic converter is detected in that the total actual oxygen supply value and an oxygen amount starting value, which characterizes the defined oxygen amount, are added up.
23. The method according to claim 16, wherein:a further active operating mode is detected, wherein steps S2-S4 are carried out separately and in parallel for each of the detected active operating modes, and wherein:it is detected which percentage operating mode proportion the respective operating mode has in a current overall operation of the internal combustion engine,the respective actual oxygen supply value is multiplied by the associated one of the percentage operating mode proportions, andin step S5, the overall actual oxygen supply value is detected in that the operating mode proportion-weighted actual oxygen supply values are added.
24. The method according claim 16, wherein:if a lambda value (λ) is detected in step S2 which lies outside the lambda value ranges stored in the characteristic maps, an extrapolation factor is determined, and an oxygen supply partial value determined from the corresponding characteristic map, which corresponds to a closest one of the lambda values (λ) stored in the characteristic map, is multiplied by the extrapolation factor before step S5.
25. The method according to claim 16, wherein:based on an oxygen absorption capacity of the catalytic converter, an absorption correction factor is determined which, if the catalytic converteris fully capable of absorbing oxygen, is at least 1 or greater,is partially capable of absorbing oxygen, is less than 1 and greater than 0, oris not capable of absorbing oxygen at all, is 0,wherein the absorption correction factor is multiplied by the overall actual oxygen supply value.
26. The method according to claim 16, wherein:an overrun operation combustion chamber number is detected, which characterizes a number of combustion chambers of the internal combustion engine which are operated in an unfired overrun operation, and a combustion chamber-individual overrun operation oxygen supply value is determined on the basis of an air mass flow fed through an unfired combustion chamber in overrun operation, andif the overrun operation combustion chamber number is less than a total number of the combustion chambers of the internal combustion engine,a combustion chamber correction factor is calculated, which specifies a ratio of the overrun operation combustion chamber number to the total number of the combustion chambers,the combustion chamber correction factor and the actual oxygen supply value are multiplied, from which an overrun operation-corrected actual oxygen supply value results,the overrun operation oxygen supply value and the overrun operation combustion chamber number are multiplied, from which an actual combustion chamber oxygen supply value results,the overrun operation-corrected actual oxygen supply value and the actual combustion chamber oxygen supply value are added to form the overall actual oxygen supply value, orif the overrun operation combustion chamber number and the total number of the combustion chambers are equal, the overrun operation oxygen supply value and the overrun operation combustion chamber number are multiplied, from which the overall actual oxygen supply value results.
27. A catalytic device for an internal combustion engine, wherein the catalytic device is configured to carry out the method according to claim 16.
28. An internal combustion engine, on the exhaust gas side of which the catalytic converter of a catalytic device configured according to claim 27 is connected, wherein the internal combustion engine accepts the oxygen requirement value as a control signal, and as a result is controllable such that it provides an oxygen supply by way of which the target oxygen amount is set in the catalytic converter.
29. A control method for controlling an internal combustion engine configured according to claim 28, wherein it is controlled so that it provides an oxygen supply, by way of which the target oxygen amount is set in the catalytic converter.
30. A motor vehicle having an internal combustion engine configured according to claim 29.