DE102018006641A1 - Exhaust system for a motor vehicle and method for operating an exhaust system - Google Patents

Abstract

The invention relates to an exhaust system 10 for a motor vehicle, with a first exhaust line (24) in which a first particle filter (28) is arranged, and with a second exhaust line (26) in which a second particle filter (30) is arranged Exhaust system (10) comprises a switching device (32). In a first switching state of the switching device (32), the first particle filter (28) and in a second switching state of the switching device (32) the second particle filter (30) can be supplied with exhaust gas. The exhaust system (10) has means (34) for regenerating the particulate filter (28, 30) that is not exposed to exhaust gas. The invention also relates to a method for operating such an exhaust system (10).

Description

The invention relates to an exhaust system for a motor vehicle with a first exhaust line, in which a first particle filter is arranged, and with a second exhaust line, in which a second particle filter is arranged. Furthermore, the invention relates to a method for operating such an exhaust system.

The DE 10 2011 010 595 A1 describes a dual-flow exhaust system of a vehicle, in which the exhaust gas of an internal combustion engine of the vehicle flows through two exhaust lines of the exhaust system in parallel. A particle filter is arranged in each of the two exhaust lines.

The cleaning of a diesel particle filter of a motor vehicle from soot is based on the chemical oxidation of the soot at high temperatures of more than 550 ° C. to carbon dioxide. In the conventional regeneration or cleaning of the diesel particle filter, the thermal energy and the required oxygen are provided by appropriate operation of the internal combustion engine of the motor vehicle, that is to say, for example, by diesel engine combustion.

To clean or regenerate a particle filter for an internal combustion engine designed as a diesel engine or as a gasoline engine, a considerable fuel input is usually required to bring the particle filter to the temperature required for burning off soot. This leads to increased fuel consumption in the motor vehicle and thus to increased CO ₂ emissions.

Another disadvantage of a conventional method for regenerating a particle filter is an increased fuel input into the engine oil. Such an oil dilution mainly occurs when post-injections are carried out into the respective combustion chambers of the internal combustion engine during the regeneration operation. The fuel which is not completely burned in such late post-injections can run along a wall of the respective cylinder in which the combustion chamber is formed. The fuel that is introduced into the internal combustion engine via post-injections can thus partially get into the engine oil.

If the exhaust system has a high-pressure exhaust gas recirculation device, in which a recirculation of exhaust gas into the supply air compressed by means of a compressor takes place, then the high-pressure exhaust gas recirculation cannot be carried out during the regeneration of the particle filter. Because the temperature of the exhaust gas downstream of the internal combustion engine is too high for such exhaust gas recirculation. However, if high-pressure exhaust gas recirculation is not carried out, this leads to increased nitrogen oxide emissions from the motor vehicle. This is also disadvantageous.

For motor vehicles which are designed as hybrid vehicles are in the DE 10 2015 015 794 A1 or in the DE 10 2016 014 255 A1 Described a method in which a particle filter is regenerated while the internal combustion engine is switched off, that is, while no fuel is being introduced into the internal combustion engine. In the DE 10 2015 015 794 A1 the particle filter is heated electrically and an air flow is applied while the hybrid vehicle is in electric driving mode. And with the DE 10 2016 014 255 A1 The particle filter is regenerated when the internal combustion engine is switched off after a partial combustion of soot in the particle filter.

In such methods, in which the motor vehicle has a partially electrified drive train, the regeneration of the particle filter can therefore be carried out without engine combustion. This eliminates the problems associated with regenerating the particulate filter by introducing additional fuel into the exhaust gas. This is because the thermal energy and the oxygen required to oxidize the soot are provided in particular through the use of electrical components and without (diesel) engine combustion.

However, it is desirable, even in a vehicle with a conventional drive, ie with a purely internal combustion engine drive, to enable the particle filter to be cleaned without engine combustion.

It is therefore an object of the present invention to provide an exhaust system of the type mentioned which has been improved in this regard and a corresponding method for operating such an exhaust system.

This object is achieved by an exhaust system with the features of claim 1 and by a method with the features of claim 8. Advantageous refinements with expedient developments of the invention are specified in the dependent claims.

The exhaust system for a motor vehicle according to the invention comprises a first exhaust line, in which a first particle filter is arranged, and a second exhaust line, in which a second particle filter is arranged. Also includes the exhaust system a switching device. In a first switching state of the switchover device, exhaust gas can be applied to the first particle filter. In a second switching state of the switchover device, exhaust gas can be applied to the second particle filter. The exhaust system has means for regenerating the particulate filter that is not in each case exposed to exhaust gas. In particular, a continuous regeneration of the particulate filter not in each case exposed to exhaust gas can be carried out. Due to this continuous cleaning, the particle filter can be particularly small. This leads to a saving in material costs, in particular in costs for coating the particle filter with precious metals, provided that a surface of the particle filter is coated with precious metals.

Furthermore, the particle filter to be regenerated can be heated up particularly quickly due to the small size. This is also advantageous with regard to the effortless regeneration of the particle filter. If the particle filter that is not exposed to exhaust gas is heated and the air or oxygen is supplied to the particle filter to be regenerated by means of electrically operated devices, a massive reduction in carbon dioxide emissions and nitrogen oxide emissions during cleaning or regeneration can also be achieved of the particle filter. In particular, a ki factor of approximately zero can be achieved. The ki factor describes the ratio of carbon dioxide emissions and fuel consumption over 100 kilometers including regeneration divided by carbon dioxide emissions and fuel consumption over 100 kilometers without regeneration.

Furthermore, it can be achieved that the regeneration of the particle filter does not influence the normal driving event of the motor vehicle having the exhaust system. In addition, a reduction in the oil dilution can be achieved, as takes place due to a conventional particle filter cleaning, in which fuel is introduced into the exhaust gas via late post-injections. Accordingly, an improved exhaust system is created.

The switchover device is preferably arranged downstream of at least one further exhaust gas aftertreatment device. The at least one additional exhaust gas aftertreatment device has exhaust gas flowing through it in every switching state of the switching device during operation of the exhaust gas system.

The at least one further exhaust gas aftertreatment device can comprise an oxidation catalytic converter and / or at least one SCR catalytic converter. In this way, an improved cleaning of the exhaust gas of the internal combustion engine of the motor vehicle can be achieved, and yet the complexity of the exhaust system is kept comparatively low.

In addition, with such an arrangement, the at least one SCR catalytic converter can be arranged particularly close to the internal combustion engine. This means that the time until the SCR catalytic converter starts, ie the so-called "light-off time", can be significantly reduced. The currently existing problem can also be countered that, because engines are becoming more and more efficient, the comparatively low temperatures of the exhaust gas usually involve a longer period of time for reaching the light-off temperature of exhaust gas aftertreatment devices such as SCR catalysts.

The respective particle filter can be designed as a particle filter for an internal combustion engine designed as a diesel engine, ie as a diesel particle filter, or as a particle filter for an internal combustion engine designed as a gasoline engine, ie as a gasoline particle filter. The drive train of a motor vehicle, for which the exhaust system according to the invention can be provided, can also be designed as a hybridized drive train, in which both an electric machine and an internal combustion engine are provided as drive machines. Accordingly, the particle filter can be cleaned by using the two floods or the two exhaust lines without engine combustion, both in a motor vehicle with a diesel engine and in a motor vehicle with a gasoline engine, as well as in a motor vehicle with a hybrid drive train which has an internal combustion engine designed as a gasoline engine or as a diesel engine , applicable.

The means for regenerating the respective particle filter preferably comprise an electrically operable air pump, by means of which air can be introduced into the first exhaust line or into the second exhaust line.

To effect the introduction of air into the first exhaust line or into the second exhaust line by means of the air pump, the exhaust system can comprise a 3-way valve.

Furthermore, the means for regenerating the particulate filter not in each case acted upon with exhaust gas can comprise at least one electric heating element.

That of the electrically operated air pump or secondary air pump and that of the at least one electric heating element The electrical power required can be provided in the motor vehicle by an electrical energy store.

The at least one electrical heating element can be arranged upstream of the particle filter in the respective exhaust line. For example, heating elements designed as glow plugs can be arranged in the exhaust pipe or in the exhaust line. Additionally or alternatively, the at least one electrical heating element can be arranged in an inlet area of the respective particle filter. The at least one heating element can therefore be arranged in front of or in the inlet or inlet area of the respective particle filter.

In a third switching state of the switching device, both the first particle filter and the second particle filter can preferably be acted upon with exhaust gas. Accordingly, a reduction in the exhaust gas back pressure of the exhaust system can be achieved by opening both floods or both exhaust gas lines. This has an advantage in terms of fuel consumption and leads to an increase in performance, in particular in the full-load range or full-load operation of the internal combustion engine of the motor vehicle.

In the method according to the invention for operating an exhaust system for a motor vehicle, exhaust gas which is introduced into a first exhaust line of the exhaust system flows through a first particle filter arranged in the first exhaust line. If, on the other hand, the exhaust gas is introduced into a second exhaust line in the exhaust system, the exhaust gas flows through a second particle filter arranged in the second exhaust line. A changeover device of the exhaust system is either brought into a first switching state in which exhaust gas is applied to the first particle filter or into a second switching state in which exhaust gas is applied to the second particle filter. The particulate filter, in each case not charged with exhaust gas, is regenerated at least temporarily, while the switchover device is in the first switching state or in the second switching state. As a result, an improved method for operating an exhaust system is created.

The advantages and preferred embodiments described for the exhaust system according to the invention also apply to the method according to the invention and vice versa.

Further advantages, features and details of the invention result from the following description of a preferred exemplary embodiment and from the drawings. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or on their own, without the scope of Leaving invention.

• 1 stark schematisiert eine Abgasanlage eines Kraftfahrzeugs, bei welcher mittels eines stromabwärts eines SCR-Katalysators angeordneten 3-Wege-Ventils wahlweise ein erster Abgasstrang mit einem ersten Partikelfilter oder ein zweiter Abgasstrang mit einem zweiten Partikelfilter mit Abgas beaufschlagt werden kann;
• 2 einen ersten Betriebszustand der Abgasanlage, in welchem das Abgas einer Verbrennungskraftmaschine des Kraftfahrzeugs durch den ersten Abgasstrang strömt und somit Partikel mittels des ersten Partikelfilters zurückgehalten werden, während der zweite, nicht mit Abgas beaufschlagte Partikelfilter regeneriert wird; und
• 3 einen zweiten Betriebszustand der Abgasanlage, in welchem das Abgas der Verbrennungskraftmaschine durch den zweiten Abgasstrang strömt und somit Partikel mittels des zweiten Partikelfilters zurückgehalten werden, während der erste, nicht mit Abgas beaufschlagte Partikelfilter regeneriert wird.

Show:

• 1 highly schematized an exhaust system of a motor vehicle, in which by means of a 3-way valve arranged downstream of an SCR catalytic converter, a first exhaust line with a first particle filter or a second exhaust line with a second particle filter can optionally be supplied with exhaust gas;
• 2 a first operating state of the exhaust system, in which the exhaust gas of an internal combustion engine of the motor vehicle flows through the first exhaust line and thus particles are retained by means of the first particle filter, while the second particle filter which is not exposed to exhaust gas is regenerated; and
• 3 a second operating state of the exhaust system, in which the exhaust gas of the internal combustion engine flows through the second exhaust line and thus particles are retained by means of the second particle filter, while the first particle filter which is not exposed to exhaust gas is regenerated.

In 1 is a highly schematic exhaust system 10 of a motor vehicle shown. That of an internal combustion engine 12 Exhaust gas coming from the motor vehicle is discharged via an exhaust pipe 14 the exhaust system 10 fed to a plurality of exhaust gas aftertreatment devices. In the exhaust system shown here by way of example 10 include these exhaust gas aftertreatment devices, which are in the exhaust pipe 14 are arranged, an oxidation catalyst 16 , a first SCR catalytic converter 18 and a second SCR catalyst 20 , In the respective SCR catalytic converter 18 . 20 are in a selective catalytic reduction reaction (SCR = selective catalytic reduction, selective catalytic reduction) in the exhaust gas of the internal combustion engine 12 contained nitrogen oxides converted with ammonia to nitrogen and water. The ammonia usually comes from urea, which is introduced into the exhaust gas in the form of an aqueous urea solution.

The second SCR catalytic converter 20 which is downstream one in the exhaust pipe 14 arranged exhaust flap 22 is located in the area of an underbody of the motor vehicle. Downstream of this second SCR catalytic converter 20 the exhaust pipe divides 14 into a first exhaust line 24 and a second exhaust line 26 on. There is a first particle filter in the first exhaust line 28 arranged, and in the second exhaust line 26 is a second particle filter 30 arranged. At that point of the exhaust system 10 , on which the common exhaust pipe 14 in the first exhaust line 24 on the one hand and the second exhaust line 26 on the other hand, the exhaust system points 10 a switching device, which in the present case is designed as a 3-way valve 32. Switching the 3-way valve 32 can achieve that of the second SCR catalytic converter 20 Coming exhaust gas optionally in the first exhaust line 24 is introduced or in the second exhaust line 26 is introduced. Accordingly, this switching device can ensure that only the first particle filter is selected 28 or just the second particle filter 30 is traversed by exhaust gas.

The exhaust system 10 allows one of the two particle filters 28 . 30 to regenerate without the required thermal energy and the required oxygen by operating the internal combustion engine accordingly 12 to be provided. The exhaust system 10 namely includes means 34 to regenerate the respective particle filter 28 . 30 , and the means 34 are operated electrically in the present case. For introducing air into the particle filter to be regenerated 28 . 30 is accordingly an electrically operated or electrically controlled air pump 36 intended. In an outlet 38 this air pump 36 or secondary air pump, which acts as an air supplier for the particle filter to be regenerated 28 . 30 is used, a further 3-way valve 40 is arranged. From the 3-way valve 40 leads a first air duct 42 towards the first exhaust line 24 and a second air duct 44 towards the second exhaust line 26 , Depending on the switching position of the 3-way valve 40 can be caused by the air pump 36 conveyed air or secondary air via the first air duct 42 in the first exhaust line 24 reaches or via the second air duct 44 in the second exhaust line 26 ,

The means 34 further comprise a first electric heating element 46 which is in the first exhaust line 24 is arranged, and a second electric heating element 48 , which is in the second exhaust line 26 is arranged. By means of these electrical heating elements 46 . 48 the respective particle filter 28 . 30 one for regeneration, i.e. for burning off that in the particle filter 28 . 30 retained soot, required temperature. The respective heating element 46 . 48 can be in front of or in an inlet or inlet of the respective particle filter 28 . 30 be arranged. Additionally or alternatively, the electrical heating elements 46 . 48 be designed as glow plugs or the like, which in the respective exhaust pipe or exhaust line 24 . 26 are arranged.

That the two floods or the two exhaust lines 24 . 26 comprehensive system with the two particle filters 28 . 30 is thus present downstream of the exhaust gas aftertreatment devices in the form of the oxidation catalytic converter 16 and the SCR catalysts 18 . 20 arranged. The exhaust system is downstream of the SCR system 10 thus in the two floods or exhaust lines 24 . 26 divided up. Each of these floods or each of these exhaust lines 24 . 26 is with the respective particle filter 28 . 30 and the respective electrical heating element 46 . 48 provided while the oxygen supply by means of the air pump 36 is ensured to the regeneration of the respective particle filter 28 . 30 to effect. The two particle filters 28 . 30 each can be loaded with precious metals in the order of about 1 gram per liter volume of the respective particle filter 28 . 30 exhibit.

Switching between the two floods or exhaust lines 24 . 26 is in the present case via the 3-way valve 32 ensured. Regarding 2 and 3 should switch between the two exhaust lines 24 . 26 and the regeneration of the particulate filter that is not exposed to exhaust gas 28 . 30 are illustrated.

Accordingly, the exhaust system is shown in the illustration 10 according to 2 the 3-way valve 32 is brought into a first switching position, in which the entire through the exhaust pipe 14 flowing exhaust continues through the first exhaust line 24 and thus through the first particle filter 28 is directed. The corresponding exhaust gas mass flow is in 2 by a plurality of arrows 50 illustrated. Accordingly, using the 3-way valve 32 in the in 2 illustrated situation, i.e. when the 3-way valve is in the first switching state 32 the second exhaust line 26 separated from the exhaust gas mass flow, which is from the internal combustion engine 12 or comes from the engine. The soot contained in the exhaust gas mass flow is therefore filtered exclusively by means of the first particle filter 28 instead of. In this first switching state, the roughly in the form of the 3-way valve 32 The switching device provided is thus the second exhaust line 26 closed or not exposed to exhaust gas.

In this switching state of the switching device, the means are also 34 operated such that cleaning of the second particle filter 30 takes place. Accordingly, the thermal energy required for regeneration is in the second particle filter 30 by energizing the second heating element 48 brought in. The oxygen required for regeneration is supplied by the electrically operated air pump 36 respectively Secondary air pump. Accordingly, the 3-way valve 40 is brought into a switching position in which the air pump 36 conveyed air only via the second air duct 44 into the exhaust system 10 is introduced, namely in the second exhaust line 26 the exhaust system 10 ,

In the time in which the second flood or the second exhaust line 26 thus separated from the exhaust gas mass flow, it can be found in this second flood or in this second exhaust line 26 second particle filter 30 be regenerated. In the other flood or in the other exhaust line 24 the soot formed by the internal combustion engine is filtered out of the exhaust gas mass flow. While the introduction of thermal energy in the 2 shown state of the exhaust system 10 via the second heating element 48 takes place and the supply of oxygen to the second particulate filter 30 by means of the air pump 36 is accomplished, this is at least one electrical first heating element 46 , which is in the first exhaust line 24 is not supplied with electrical current.

If the in the first exhaust line 24 arranged first particle filter 28 its loading limit, i.e. a corresponding loading with particles or soot from that of the internal combustion engine 12 coming exhaust gas is reached by means of the 3-way valve 32 this first flood or this first exhaust line 24 separated from the exhaust gas mass flow. This state of the exhaust system 10 is in 3 illustrated. That of the internal combustion engine or the internal combustion engine 12 Soot generated is therefore only from the second exhaust line 26 or directed over the second flood. Accordingly, the soot is filtered in the exhaust gas mass flow via the second exhaust line 26 or by means of the second particle filter 30 , The corresponding exhaust gas mass flow is in 3 by further arrows 52 illustrated. Accordingly, when the 3-way valve flows 32 is brought into the second switching state, no exhaust gas through the first exhaust line 24 , In contrast, the at least one first electrical heating element 46 which is in the first exhaust line 24 is arranged, supplied with electrical energy to the first particle filter 28 heat. At the same time, the 3-way valve 40 made sure that from the air pump 36 Pumped air or secondary air only via the first air duct 42 in the first exhaust line 24 is introduced.

After this cleaning of the first flood or that in the first exhaust line 24 located first particle filter 28 becomes the 3-way valve 32 switched so that the second exhaust line 26 is separated from the exhaust gas mass flow and that in the second exhaust line 26 arranged second particle filter 30 is regenerated. It will then become the exhaust system 10 again operated as above with reference to 2 has been explained. Accordingly, that of the internal combustion engine or the internal combustion engine 12 soot then generated again in the first exhaust line 24 the first particle filter 28 filtered.

In the following, further components of the exhaust system, shown here by way of example, are intended 10 or the motor vehicle are described. This is how the internal combustion engine works 12 Air or supply air supplied in internal combustion engine operation, which in 2 and in 3 by a respective arrow 54 is illustrated after flowing through an air filter 56 which is in a supply air duct 58 is arranged, a compressor 60 of an exhaust gas turbocharger 62 fed.

The exhaust gas turbocharger 62 comprises a turbine in a manner known per se 64 which in the exhaust pipe 14 is arranged. It can be an adjuster 66 for setting a variable turbine geometry of the turbine 64 be provided. On a high pressure side of the compressor 60 is in the supply air line 58 a charge air cooler 68 , which has a throttle valve 70 is connected downstream. A swirl flap can also be used to switch off the inlet duct 72 be provided.

Upstream of that in the exhaust pipe 14 arranged turbine 64 can be an exhaust gas recirculation line 74 in which a valve 76 is arranged, the exhaust pipe 14 with a high pressure side of the supply air line 58 connect, i.e. with a downstream of the compressor 60 arranged section of the supply air line 58 , In the exhaust gas recirculation line designed for a corresponding high pressure exhaust gas recirculation 74 is an exhaust gas recirculation cooler 78 arranged. The exhaust gas recirculation cooler 78 can bypass 80 in which another valve 82 is arranged to be bypassed.

Another exhaust gas recirculation line 84 for low-pressure exhaust gas recirculation branches between the first SCR catalytic converter 18 and the exhaust flap 22 from the exhaust pipe 14 and flows downstream of the air filter 56 and upstream of the compressor 60 in the supply air line 58 on. Also in this exhaust gas recirculation line 84 are an exhaust gas recirculation cooler 86 and a valve 88 arranged.

By dividing the exhaust pipe 14 into the two floods or two exhaust lines 24 . 26 with the respective particle filter 28 . 30 and the provision of the means 34 to regenerate the particulate filter that is not exposed to exhaust gas 28 . 30 can also clean or regenerate the respective particle filter for a motor vehicle such as a passenger car with a conventional drive 28 . 30 can be achieved without having to burn fuel for this regeneration.

It can also be used for conventional passenger cars with an internal combustion engine designed as a diesel engine or as a gasoline engine 12 cleaning the particle filter 28 . 30 can be achieved without engine combustion.

LIST OF REFERENCE NUMBERS

10

exhaust system

12

Internal combustion engine

14

exhaust pipe

16

oxidation catalyst

18

SCR catalyst

20

SCR catalyst

22

exhaust flap

24

first exhaust line

26

second exhaust line

28

first particle filter

30

second particle filter

32

3-way valve

34

medium

36

air pump

38

outlet

40

3-way valve

42

air duct

44

air duct

46

heating element

48

heating element

50

arrow

52

arrow

54

arrow

56

air filter

58

Zuluftstrang

60

compressor

62

turbocharger

64

turbine

66

Steller

68

Intercooler

70

throttle

72

swirl flap

74

Exhaust gas recirculation line

76

Valve

78

Exhaust gas recirculation cooler

80

bypass

82

Valve

84

Exhaust gas recirculation line

86

Exhaust gas recirculation cooler

88

Valve

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011010595 A1 [0002]
• DE 102015015794 A1 [0007]
• DE 102016014255 A1 [0007]

Claims (9)

Exhaust system for a motor vehicle, with a first exhaust line (24), in which a first particle filter (28) is arranged, and with a second exhaust line (26), in which a second particle filter (30) is arranged, characterized in that the exhaust system (10) comprises a switchover device (32), the first particle filter (28) in a first switching state of the switchover device (32) and the second particle filter (30) in a second switching state of the switchover device (32), and wherein the Exhaust system (10) has means (34) for regenerating the particulate filter (28, 30) that is not exposed to exhaust gas. Exhaust system after Claim 1 , characterized in that the switchover device (32) is arranged downstream of at least one further exhaust gas aftertreatment device, through which exhaust gas flows in every switching state of the switchover device (32) during operation of the exhaust gas system (10). Exhaust system after Claim 2 , characterized in that the at least one further exhaust gas aftertreatment device comprises an oxidation catalytic converter (16) and / or at least one SCR catalytic converter (18, 20). Exhaust system according to one of the Claims 1 to 3 , characterized in that the means (34) for regenerating the respective particle filter (28, 30) comprise an electrically operated air pump (36) by means of which air can be introduced into the first exhaust line (24) or into the second exhaust line (26). Exhaust system after Claim 4 , characterized by a 3-way valve (40) for effecting the introduction of the air optionally into the first exhaust line (24) or into the second exhaust line (26) by means of the air pump (36). Exhaust system according to one of the Claims 1 to 5 , characterized in that the means (34) for regenerating the particulate filter (28, 30) which is in each case not exposed to exhaust gas comprise at least one electrical heating element (46, 48) which is located upstream of the particulate filter (28, 30) in the respective exhaust gas line (24 , 26) and / or in an inlet area of the respective particle filter (28, 30). Exhaust system according to one of the Claims 1 to 6 , characterized in that in a third switching state of the switching device (32) both the first particle filter (28) and the second particle filter (30) can be acted upon with exhaust gas. Exhaust system according to one of the preceding claims, characterized in that the motor vehicle is designed as a hybrid vehicle and, in addition to an internal combustion engine (12), has an electric machine as the drive machine. Method for operating an exhaust system (10) for a motor vehicle, in which exhaust gas which is introduced into a first exhaust line (24) of the exhaust system (10) flows through a first particle filter (28) arranged in the first exhaust line (24), and at Which exhaust gas, which is introduced into a second exhaust line (26) of the exhaust system (10), flows through a second particle filter (30) arranged in the second exhaust line (26), characterized in that a switching device (32) of the exhaust system (10) is optional is brought into a first switching state in which exhaust gas is applied to the first particle filter (28) or to a second switching state in which exhaust gas is applied to the second particle filter (30), the particle filter (28, 30) is regenerated at least temporarily while the switching device (32) is in the first switching state or in the second switching state.

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