Method of monitoring particulate filter regeneration in exhaust system of internal combustion engine

Abstract

The invention relates to a method for monitoring a particle filter (40) in an exhaust gas system (30) of an internal combustion engine (10). The method comprises the steps of: determining a loading of the particulate filter (40) by means of a pressure difference measurement between an inlet of the particulate filter (40) and an outlet of the particulate filter (40), modeling the loading of the particulate filter (40) by means of a soot loading model for the particulate filter (40), initiating regeneration of the particulate filter (40), the particulate removal from the particulate filter (40) determined by the differential pressure measurement is compared with the particulate removal modeled by the soot loading model, and an error report is output when the difference between the calculated particulate removal and the measured particulate removal exceeds a threshold. The invention also relates to an internal combustion engine (10) having a control unit (60) and an exhaust gas system (30) in order to carry out such a method.

Description

Technical Field

[0001] The invention relates to a method for monitoring the regeneration of a particle filter in an exhaust system of an internal combustion engine, and to an internal combustion engine having an exhaust system and a control unit for carrying out this method, according to the preambles of the independent claims. Background Art

[0002] The ever-increasing severity of exhaust gas legislation places high demands on vehicle manufacturers, which are met by appropriate measures to reduce the raw emissions of the engine and by appropriate exhaust gas aftertreatment. With the introduction of EU6 legislation, limit values ​​for the number of particles are set for gasoline engines, which in many cases require the use of gasoline particle filters. Such soot particles are formed in particular after a cold start of the internal combustion engine due to incomplete combustion in combination with a substoichiometric combustion air ratio after a cold start, cold cylinder walls and an inhomogeneous mixture distribution in the combustion chamber of the internal combustion engine. In contrast to the loading of diesel particle filters, the soot loading of gasoline particle filters depends essentially on the combustion chamber temperature and decreases with increasing combustion chamber temperature. The cold start phase is therefore crucial for compliance with the legally prescribed particle limit values ​​for particle mass and particle number. At cold outside temperatures, in particular at ambient temperatures below 0°C, particularly high particle emissions are emitted in gasoline engines due to low mixture homogeneity and fuel evaporation as well as start enrichment. In addition, cold starts with a rich combustion air ratio below the stoichiometric ratio lead to higher emissions of carbon monoxide (CO) and unburned hydrocarbons (HC), since conversion into carbon dioxide and water vapor is still not possible due to the cold catalytic converter. During driving operation of a motor vehicle with a gasoline particle filter, the gasoline particle filter is then further loaded with soot. In order to prevent the exhaust gas back pressure from rising too much, the gasoline particle filter must be regenerated continuously or periodically. The increase in exhaust gas back pressure leads to additional consumption of the internal combustion engine, power loss and adverse effects on running smoothness, and may even lead to ignition failure. In order to thermally oxidize the soot retained in the gasoline particle filter with oxygen, a sufficiently high temperature level and the simultaneous presence of oxygen in the exhaust system of the gasoline engine are required. Since modern gasoline engines usually operate at a stoichiometric combustion air ratio (λ=1) without excess oxygen, additional measures are required. For this purpose, for example, measures to increase the temperature by adjusting the ignition angle, intermittent lean control of the gasoline engine, injection of secondary air into the exhaust system, increase of the idling speed or a combination of these measures are considered. Up to now, the adjustment of the ignition angle in the retarded direction has been combined with a lean control of the gasoline engine, since this method does not require additional components and can provide a sufficient amount of oxygen at most operating points of the gasoline engine. In addition, with the introduction of new, more stringent exhaust gas standards, it may be provided that the correct function of the exhaust gas aftertreatment components is continuously monitored within the framework of on-board monitoring by means of appropriate sensors in the exhaust gas system.

[0003] A method for determining the state of an exhaust gas treatment element for a motor vehicle is known from document DE 10 2018 217 047 A1. The exhaust gas treatment element has a filter with a catalytic coating. The method comprises the following steps:

[0004] - determine the actual value of the quantity representing the storage capacity of the coating,

[0005] - determining a nominal value for said quantity,

[0006] - determine the difference between the actual value and the nominal value, and

[0007] - determining a state of a filter of the exhaust gas treatment element as a function of the determined difference.

[0008] Document DE 10 2020 103 894 A1 describes a method for monitoring the regeneration of a particle filter arranged in the exhaust system of a gasoline engine. The method comprises the following steps:

[0009] a) determining according to which regeneration stage of a defined number of regeneration stages the particle filter is regenerated or has been regenerated last;

[0010] b) monitoring the extent of at least one first check criterion for characterizing a change in the loading of the particle filter,

[0011] c) Checking whether a first check criterion is met, and if the first check criterion is not met, switching to a higher regeneration level, and if the first check criterion is met, switching to a lower regeneration level or maintaining the current regeneration level.

[0012] Document DE 10 2020 206 042 A1 describes a method for modeling a pressure difference dropping across a particle filter in an exhaust system of an internal combustion engine. The method comprises the following steps: detecting at least two pressure difference values ​​by means of a pressure sensor, detecting respectively associated volume flow values ​​for the at least two pressure difference values; and interpolating a modeled pressure curve from the at least two detected pressure difference values ​​and the associated volume flow values. Summary of the invention

[0013] The object of the present invention is to detect an incomplete regeneration of a particle filter in an exhaust system of a gasoline engine and to prevent too frequent initiation of a new regeneration of the particle filter or a failure of a necessary regeneration of the particle filter.

[0014] This object is achieved by a method for monitoring a particle filter in an exhaust system of an internal combustion engine. The internal combustion engine has at least one combustion chamber, on which a spark plug for igniting a combustible fuel-air mixture is arranged. The internal combustion engine also has a fuel injection valve for injecting fuel into the combustion chamber and / or a fuel injection valve for injecting fuel into an intake duct of the internal combustion engine. Preferably, the internal combustion engine has a plurality of combustion chambers, wherein a fuel injector for injecting fuel into the combustion chamber and a spark plug for igniting the fuel-air mixture are arranged on each combustion chamber. The method comprises at least the following steps:

[0015] - determining the loading of the particle filter by means of a differential pressure measurement between the inlet of the particle filter and the outlet of the particle filter,

[0016] - modelling of the loading of the particle filter by means of a soot loading model for the particle filter,

[0017] - start regeneration of the particle filter,

[0018] - comparing the particle removal from the particle filter determined by differential pressure measurements with the particle removal modeled by a soot loading model,

[0019] - Output an error report when the difference between the calculated particle removal and the measured particle removal exceeds a threshold.

[0020] The method according to the invention, in particular the comparison of the calculated particle removal carried out during the regeneration of the particle filter with the particle removal "measured" by the differential pressure measurement, makes it possible to monitor the regeneration of the particle filter and in particular to detect whether the soot emission based on the model is consistent with the measured soot emission from the particle filter. The regeneration of the particle filter is usually associated with engine-internal measures that lead to limited pollutant emissions and / or increased consumption. The method according to the invention can prevent incomplete regeneration of the particle filter and the resulting increase in emissions during operation of the internal combustion engine due to an incorrect determination of the load state.

[0021] Advantageous refinements and improvements of the method for monitoring a particle filter in an exhaust system of an internal combustion engine described in the independent claim are possible by means of the features described in the dependent claims.

[0022] In a preferred embodiment of the invention, it is provided that a loading model for the particle filter is formed as a function of the pressure difference across the particle filter. This makes it particularly easy to diagnose whether a complete regeneration of the particle filter has been achieved. The soot loading model reflects the expected value for the soot loading.

[0023] In an advantageous embodiment of the invention, it is provided that an error in the regeneration is detected if the differential pressure does not decrease during the regeneration of the particle filter. During the regeneration of the particle filter, the differential pressure should continuously decrease due to the discharge of soot from the particle filter and the associated reduction in the flow resistance in the particle filter. If the differential pressure increases or remains constantly at a high level during the regeneration of the particle filter, an error is present and the particle filter cannot be regenerated as desired. The method makes it possible to detect such an error in an operationally safe manner in order to prevent further damage to the particle filter and / or to avoid an unacceptable increase in emissions.

[0024] In another preferred embodiment of the present invention, it is provided that the regeneration of the particle filter is started only when the pressure difference exceeds a threshold value. Thus, a start signal for starting the regeneration of the particle filter can be given in a simple manner. In addition, it is possible to prevent the consumption and / or emissions of the internal combustion engine from increasing due to too frequent regeneration of the particle filter.

[0025] It is particularly preferred that the soot loading model is initialized when the threshold value is exceeded and the particle filter is subsequently activated. The loading measured by the differential pressure measurement and the loading determined by the soot loading model can thus be compared, so that the loading and, in particular, the removal of particles from the particle filter to the outside during the regeneration process can be determined.

[0026] In an advantageous embodiment of the invention, provision is made for the loading of the particle filter to be divided into a plurality of stages, wherein regeneration of the particle filter is initiated or terminated depending on the level of loading of the particle filter reached. Thus, a plurality of stages can be formed in the model, wherein in the lowest stage, a barely noticeable regeneration of the particle filter takes place, while in other stages, a more intense regeneration of the particle filter is achieved during driving of the motor vehicle, and at higher loadings the driver can be asked to have the particle filter checked in a repair shop.

[0027] Alternatively, regeneration can also take place during normal operation of the motor vehicle. During normal operation of the motor vehicle, driving conditions occur in which both an exhaust gas temperature sufficient to regenerate the particle filter and an excess of oxygen in the exhaust system prevail in order to regenerate the particle filter. A typical example of such a driving condition is a power cut-off during highway driving. This operating condition results in the soot remaining in the particle filter being oxidized without the need for additional heating measures and the loading of the particle filter being reduced.

[0028] In a further development of the invention, it is provided that a warning message is output to the driver when a certain level for loading is exceeded. In this case, the regeneration in the lower level takes place inconspicuously for the driver. The regeneration in the higher level usually lasts longer and is noticeable to the driver by initiating measures in the engine, which are indicated by the warning message so that the driver can associate measures in the engine with the regeneration of the particle filter.

[0029] In a further advantageous embodiment of the method, it is provided that when a certain level of loading is exceeded, the driver is requested to visit a repair shop in order to carry out an external regeneration of the particle filter. If the particle filter reaches a critical loading level at which there is a risk of uncontrolled soot combustion and / or heat input into the particle filter during regeneration, which could lead to permanent thermal damage to the particle filter, the driver is requested to take the motor vehicle to a repair shop and carry out an external regeneration of the particle filter there in order to avoid permanent damage to the particle filter.

[0030] It is particularly preferred that, during a regeneration of the particle filter, the soot loading model is initialized as a function of the level of loading of the particle filter reached and a soot loading corresponding to this level is assigned as a starting value.

[0031] Another sub-aspect of the invention relates to a control unit for executing the method described in the preceding section, wherein the control unit comprises a storage unit and a computing unit and a computer program code stored in the storage unit, wherein the method is executed when the computer program code is executed by the computing unit.

[0032] Another sub-aspect of the invention relates to an internal combustion engine having at least one combustion chamber, wherein a fuel injector for injecting fuel into the combustion chamber is arranged on the combustion chamber and / or a fuel injection valve arrangement is arranged in the intake duct of the internal combustion engine, and a spark plug for igniting a combustible fuel-air mixture is arranged on the combustion chamber. The internal combustion engine is connected via its outlet to an exhaust system, in which a particle filter is arranged. The internal combustion engine is also connected to a control unit described above. In such an internal combustion engine, emissions can be reduced because too frequent or currently unnecessary regeneration of the particle filter and the associated increase in emissions are prevented.

[0033] In an advantageous design of the internal combustion engine, it is provided that a three-way catalytic converter is arranged as the first exhaust gas aftertreatment component in the exhaust system along the flow direction of the exhaust gas flow of the internal combustion engine through the exhaust system, and the particle filter is arranged downstream of the three-way catalytic converter. This achieves particularly advantageous exhaust gas aftertreatment, because the three-way catalytic converter quickly reaches its operating temperature after a cold start due to its position close to the engine, and thus immediately achieves effective conversion of limited pollutants in the exhaust gas flow of the internal combustion engine after a cold start of the internal combustion engine. In addition, this layout makes it possible to arrange the particle filter close to the engine, thereby simplifying the heating of the particle filter to start regeneration. In this case, the position close to the engine is understood to be the position of the inlet of the exhaust gas aftertreatment component, the exhaust gas running length of which starting from the outlet of the internal combustion engine is less than 80 cm, preferably less than 60 cm.

[0034] It is particularly preferred that the further three-way catalytic converter is arranged downstream of the particle filter. The catalytic converter volume for the three-way catalytic converter can thus be divided into two units, whereby the first three-way catalytic converter close to the engine can be designed to have a smaller volume and therefore reach its light-off temperature faster.

[0035] Alternatively, the particle filter and the additional three-way catalytic converter can also be combined in one component as a so-called four-way catalytic converter. For this purpose, the particle filter has a catalytically active coating, which is preferably applied as a carrier coating to the filter structure of the particle filter and can oxidize limited pollutants such as unburned hydrocarbons and carbon monoxide, as well as reduce nitrogen oxides.

[0036] In an advantageous embodiment, the internal combustion engine is designed as an externally ignited internal combustion engine according to the gasoline engine principle, which is supercharged by an exhaust gas turbocharger. By supercharging the internal combustion engine, the filling in the combustion chamber of the internal combustion engine can be improved. This can be combined in particular with a fuel injector that can provide an injection pressure in the range of up to 350 bar, resulting in a reduction in the original particle emissions and thus a reduction in the frequency with which the particle filter must be regenerated.

[0037] Unless otherwise stated, the different embodiments of the invention described in this application can be combined with one another in an advantageous manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is further described below in the embodiments according to the accompanying drawings.

[0039] Figure 1 A preferred embodiment is shown for an internal combustion engine having an exhaust system and a control unit for carrying out the method according to the invention for monitoring a particle filter in an exhaust system of an internal combustion engine.

[0040] Figure 2 A further preferred exemplary embodiment is shown for an internal combustion engine for carrying out the method according to the invention for monitoring a particle filter in an exhaust system of an internal combustion engine.

[0041] Figure 3 A flow chart for carrying out the method according to the invention for monitoring a particle filter in an exhaust system of an internal combustion engine is shown. DETAILED DESCRIPTION

[0042] Figure 1The schematic diagram of an internal combustion engine 10 is shown. The internal combustion engine 10 is designed as a direct injection gasoline engine. The internal combustion engine 10 has a plurality of combustion chambers 12. A fuel injector is arranged on each combustion chamber 12, and the fuel injector has a fuel injection valve 14 for injecting fuel 58 into the corresponding combustion chamber 12 and a spark plug 16 for igniting the fuel-air mixture in the corresponding combustion chamber 12. The combustion chamber 12 is defined by an axially movable piston 18. The reciprocating motion of the piston 18 is transmitted to the rotational motion of the crankshaft 28 of the internal combustion engine through a connecting rod 27. The internal combustion engine 10 is connected to an air supply system (not shown) through its inlet 20 and to an exhaust system 30 through its outlet 22. An intake valve 24 and an exhaust valve 26 are arranged on the combustion chamber 12, and a fluid connection from the air supply system to the combustion chamber 12 or from the combustion chamber 12 to the exhaust system 30 can be opened or closed by the intake valve and the exhaust valve. Alternatively or additionally, internal combustion engine 10 may also have one or more fuel injection valves 14 which are arranged in an intake tract of internal combustion engine 10 .

[0043] The exhaust system 30 comprises an exhaust gas channel 32, in which a three-way catalytic converter 38 close to the engine is arranged as a first exhaust gas aftertreatment component in the flow direction of the exhaust gas flow of the internal combustion engine 10, a particle filter 40 is arranged downstream of the three-way catalytic converter close to the engine, and a second three-way catalytic converter 42 is arranged further downstream, wherein the second three-way catalytic converter 42 is preferably arranged in the bottom position of the motor vehicle. In addition, a turbine 36 of an exhaust gas turbocharger 34 can be arranged in the exhaust system 30. A first lambda sensor 44, in particular a broadband sensor, is arranged in the exhaust system downstream of the outlet 22 of the internal combustion engine 10 and upstream of the first three-way catalytic converter 38 for detecting the oxygen concentration in the exhaust gas flow. A second lambda sensor 46, in particular a jump sensor, is arranged downstream of the first three-way catalytic converter 38 and upstream of the second three-way catalytic converter 42, in particular downstream of the first three-way catalytic converter 38 and upstream of the particle filter 40. Furthermore, a first temperature sensor 50 is arranged in the exhaust system 30 downstream of the first three-way catalytic converter 38 and upstream of the particle filter 40, and a second temperature sensor 52 is arranged downstream of the particle filter 40 and upstream of the second three-way catalytic converter. A differential pressure sensor 48 is arranged on the particle filter 40, which determines the pressure difference between the inlet of the particle filter 40 and the outlet of the particle filter 40. The pressure difference on the particle filter 40 is correlated with the particle loading of the particle filter 40, wherein a regeneration of the particle filter 40 is initiated when a defined threshold value for the pressure difference is reached in order to avoid further loading of the particle filter 40 and associated potential damage.

[0044] Internal combustion engine 10 is connected to a control unit 60, which comprises a memory unit 62 and a computing unit 64. Memory unit 62 stores computer program code 66 which, when executed by the computing unit of the control unit, carries out the method according to the invention.

[0045] exist Figure 2 1 shows another preferred embodiment for an internal combustion engine 10. The internal combustion engine 10 is designed as a direct injection gasoline engine. The internal combustion engine 10 has a plurality of combustion chambers 12. A fuel injector is arranged on each combustion chamber 12, and the fuel injector has a fuel injection valve 14 for injecting fuel 58 into the corresponding combustion chamber 12 and a spark plug 16 for igniting the fuel-air mixture in the corresponding combustion chamber 12. The combustion chamber 12 is defined by an axially movable piston 18. The reciprocating motion of the piston 18 is transmitted to the rotational motion of the crankshaft 28 of the internal combustion engine via a connecting rod 27. The internal combustion engine 10 is connected to an air supply system (not shown) via its inlet 20 and to an exhaust system 30 via its outlet 22. An intake valve 24 and an exhaust valve 26 are arranged on the combustion chamber 12, and a fluid connection from the air supply system to the combustion chamber 12 or from the combustion chamber 12 to the exhaust system 30 can be opened or closed by the intake valve and the exhaust valve. Alternatively or additionally, internal combustion engine 10 may also have one or more fuel injection valves 14 which are arranged in an intake tract of internal combustion engine 10 .

[0046] The exhaust system 30 comprises an exhaust gas channel 32, in which a three-way catalytic converter 38 close to the engine is arranged as a first exhaust gas aftertreatment component in the flow direction of the exhaust gas flow of the internal combustion engine 10, and a particle filter 40 with a catalytic coating 54 is arranged downstream of the three-way catalytic converter 38 close to the engine. The particle filter 40 can be designed in particular as a so-called four-way catalytic converter 56, wherein such a four-way catalytic converter combines the functions of the three-way catalytic converter 42 and the particle filter 40 in one component. Here, the filter substrate of the particle filter 40 is applied with a carrier coating having the function of the three-way catalytic converter 42. In addition, the turbine 36 of the exhaust gas turbocharger 34 can be arranged in the exhaust system 30. Downstream of the outlet 22 of the internal combustion engine 10 and upstream of the first three-way catalytic converter 38, a first lambda sensor 44, in particular a broadband sensor, is arranged in the exhaust system for detecting the oxygen concentration in the exhaust gas flow. Downstream of the first three-way catalytic converter 38 and upstream of the particle filter 40, a second lambda sensor 46, in particular a jump sensor, is arranged.

[0047] Furthermore, a first temperature sensor 50 is arranged in the exhaust system 30 downstream of the first three-way catalytic converter 38 and upstream of the particle filter 40. A differential pressure sensor 48 is provided on the particle filter 40, which determines a differential pressure between an inlet of the particle filter 40 and an outlet of the particle filter 40. The differential pressure across the particle filter 40 is correlated with the particle loading of the particle filter 40, wherein a regeneration of the particle filter 40 is initiated when a defined threshold value for the differential pressure is reached in order to avoid further loading of the particle filter 40 and associated potential damage.

[0048] Internal combustion engine 10 is connected to a control unit 60, which comprises a memory unit 62 and a computing unit 64. Memory unit 62 stores computer program code 66 which, when executed by the computing unit of the control unit, carries out the method according to the invention.

[0049] Figure 3 A flow chart for carrying out the method according to the invention for monitoring a particle filter in an exhaust system of an internal combustion engine is shown in FIG. <100> In the process, a pressure difference across the particle filter 40 between an inlet of the particle filter 40 and an outlet of the particle filter 40 is determined, which pressure difference is correlated with the loading of the particle filter.

[0050] In the method steps <110> In the embodiment of the present invention, the loading of the particle filter 40 is additionally modeled by a soot loading model for the particle filter 40 .

[0051] In the method steps <120> In the embodiment of the present invention, when the pressure difference exceeds a predefined threshold value, which signals the need to regenerate the particle filter 40, the regeneration of the particle filter 40 is initiated. This initiation of regeneration is carried out by increasing the exhaust gas temperature to the regeneration temperature of the particle filter. The increase in the exhaust gas temperature can be carried out by internal heating measures of the engine, such as adjusting the ignition angle in the retarded direction, and / or by external heating measures, such as by an electric heating element or an exhaust gas burner in the exhaust system, wherein the external heating device is arranged upstream of the particle filter 40.

[0052] In the method steps <130> In the method step 40 , the particle removal from the particle filter determined by the pressure difference measurement during the regeneration of the particle filter 40 is compared with the particle removal modeled by the soot loading model. <125> In the embodiment of the present invention, at the beginning of the regeneration of the particulate filter 40 , the soot loading model may be initialized in order to improve the accuracy of the method.

[0053] In the method steps <140> In the example, an error report is output when the difference between the calculated particle removal and the measured particle removal exceeds a threshold.

[0054] Reference numerals list

[0055] 10 Internal combustion engine

[0056] 12 Combustion Chamber

[0057] 14 Fuel injection valve

[0058] 16 Spark plug

[0059] 18 Piston

[0060] 20 Entrance

[0061] 22 Exit

[0062] 24 Inlet valve

[0063] 26 Exhaust valve

[0064] 27 Connecting rod

[0065] 28 Crankshaft

[0066] 30 Exhaust system

[0067] 32 Exhaust channel

[0068] 34 Turbocharger

[0069] 36 Turbine

[0070] 38 First three-way catalytic converter

[0071] 40 Particle filter

[0072] 42 Second three-way catalytic converter

[0073] 44 First lambda sensor

[0074] 46 Second lambda sensor

[0075] 48 Differential pressure sensor

[0076] 50 First temperature sensor

[0077] 52 Second temperature sensor

[0078] 54 Catalytic coating

[0079] 56 Four-way catalytic converter

[0080] 58 Fuel

[0081] 60 Control Unit

[0082] 62 storage units

[0083] 64 computing units

[0084] 66 Computer program code

Claims

1. A method for monitoring the regeneration of a particle filter (40) in an exhaust system (30) of an internal combustion engine (10), wherein: An internal combustion engine (10) has at least one combustion chamber (12), on which a spark plug (16) is arranged for igniting a combustible fuel-air mixture, wherein the internal combustion engine (10) has a fuel injection valve (14) for introducing fuel into an intake duct of the internal combustion engine (10) and / or into the combustion chamber (12) of the internal combustion engine (10), the method comprising the following steps: - determining the loading of the particle filter (40) by measuring the pressure difference between the inlet of the particle filter (40) and the outlet of the particle filter (40), - modeling the loading of the particle filter (40) by means of a soot loading model for the particle filter (40), - starting the regeneration of the particle filter (40), - comparing the particle removal from the particle filter (40) determined by differential pressure measurement with the particle removal modeled by a soot loading model, and - Output an error report when the difference between the calculated particle removal and the measured particle removal exceeds a threshold.

2. The method according to claim 1, wherein: A loading model for the particle filter (40) is formed based on the determined pressure difference across the particle filter (40).

3. The method according to claim 1 or 2, wherein: If the differential pressure does not decrease during the regeneration of the particle filter, an error in the regeneration is detected.

4. The method according to any one of claims 1 to 3, wherein: Regeneration of the particle filter (40) is initiated only when the pressure difference exceeds a threshold value.

5. The method according to claim 4, wherein: When a threshold value is exceeded and the particle filter is subsequently activated, the soot loading model is initialized.

6. The method according to any one of claims 1 to 5, wherein: The loading of the particle filter (40) is divided into a plurality of stages, wherein regeneration of the particle filter is initiated or interrupted depending on the level of loading of the particle filter (40) reached.

7. The method according to claim 6, wherein: When a certain level is exceeded, a warning message is output to the driver.

8. The method according to claim 6 or 7, wherein: When a certain level of loading is exceeded, the driver is required to visit a repair shop in order to carry out an external regeneration of the particle filter. 9 . The method according to claim 4 and claim 6 , wherein the soot loading model is initialized as a function of the level of loading reached and the soot loading corresponding to this level is assigned as a starting value.

10. A control unit (60) for executing the method according to one of claims 1 to 9, wherein the control unit (60) comprises a storage unit (62) and a computing unit (64) and a computer program code (66) stored in the storage unit (62), wherein the method is executed when the computer program code (66) is executed by the computing unit (64).

11. An internal combustion engine (10) having at least one combustion chamber (12), wherein: A fuel injection valve (14) for injecting fuel (58) into the combustion chamber (12) and / or into the intake duct and a spark plug (16) for igniting a combustible fuel-air mixture are arranged on the combustion chamber (12) and / or on the intake duct of the internal combustion engine (10), wherein the internal combustion engine (10) is connected to an exhaust system (30) via its outlet (22), a particle filter (40) is arranged in the exhaust system, and the internal combustion engine also has a control unit (60) according to claim 10.

12. The internal combustion engine (10) according to claim 11, wherein: A three-way catalytic converter (38) is arranged in the exhaust system (30) as a first exhaust gas aftertreatment component along the flow direction of the exhaust gas flow of the internal combustion engine (10) through the exhaust system (30), and a particle filter (40) is arranged downstream of the three-way catalytic converter (38).

13. The internal combustion engine (10) according to claim 12, wherein: A further three-way catalytic converter (42) is arranged downstream of the particle filter (40).

14. The internal combustion engine (10) according to any one of claims 11 to 13, wherein: The particle filter (40) has a catalytically active coating (54).

15. The internal combustion engine (10) according to claim 11, wherein the internal combustion engine (10) is designed as a direct-injection gasoline engine supercharged by an exhaust gas turbocharger (30).

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