DE102020126717A1 - Method for exhaust aftertreatment of an internal combustion engine and motor vehicle with such an exhaust aftertreatment system - Google Patents

Abstract

The invention relates to a method for after-treating the exhaust gas of a spark-ignited internal combustion engine (10) in a motor vehicle (1). The internal combustion engine (10) is connected on the outlet side to an exhaust gas aftertreatment system (20), in which, in the direction of flow of an exhaust gas stream of the internal combustion engine (10) through the exhaust gas aftertreatment system (20), a first exhaust gas aftertreatment component (30), downstream of the first exhaust gas aftertreatment component (30) an external heating means ( 36) and further downstream a second exhaust gas aftertreatment component (32) are arranged. The component temperatures (TANK1, TANK2) of the exhaust aftertreatment components and their current conversion performance are determined. Depending on the determined component temperatures (TANK1, TANK2) and the current conversion performance as well as a load requirement on the internal combustion engine (10), the external heating means (36) is activated if the determined component temperature (TANK2) of the second exhaust gas aftertreatment component (32) is below a first threshold temperature (TS) and the conversion performance of the first exhaust gas aftertreatment component (30) at the determined load requirement on the internal combustion engine (10) is probably not sufficient to ensure complete conversion of the limited pollutants in the exhaust gas flow of the internal combustion engine (10).

Description

The invention relates to a method for exhaust gas aftertreatment of an internal combustion engine in a motor vehicle and a motor vehicle with an internal combustion engine with an exhaust gas aftertreatment system for carrying out such a method according to the preamble of the independent patent claims.

The current exhaust gas legislation and one that will become increasingly strict in the future place high demands on engine raw emissions and the exhaust gas aftertreatment of combustion engines. In Otto engines, the exhaust gas is cleaned in a known manner via a three-way catalytic converter, as well as further catalytic converters upstream and downstream of the three-way catalytic converter and a particle filter. Every device for catalytic exhaust gas purification requires a minimum temperature, the so-called light-off temperature, to be exceeded in order to be effective. During a cold start of a motor vehicle, the temperature level of the internal combustion engine and the components for exhaust gas aftertreatment is approximately at ambient temperature. Even with a high energy input into the exhaust system, the thermally inertial mass of the exhaust system must first be overcome and the radiation or convection losses compensated in order to achieve at least partial effectiveness of the exhaust gas aftertreatment components. During this time, the raw emissions from the internal combustion engine are emitted largely untreated. Depending on the energy input into the exhaust system, this period can be shortened, but never reduced to zero. The quicker the light-off temperatures of the catalytic converters are reached, the lower emissions the combustion engine can be operated in combination with the exhaust aftertreatment system. In addition, the actively heated catalyst volume has a significant impact on conversion performance. In order to comply with future emission regulations, it may therefore be necessary to support the achievement of the component temperatures of the exhaust gas aftertreatment components with an additional external heating measure.

From the DE 10 2012 021 573 A1 a method for controlling or regulating a burner operated with air and fuel is known, the burner exhaust gas of which is combined with an internal combustion engine exhaust gas of a spark-ignited internal combustion engine and a mixed exhaust gas thus obtained is fed to an exhaust gas catalytic converter having a three-way catalytic function. the DE 10 2012 021 573 A1 also discloses an exhaust system configured to carry out the method. It is provided that an actual oxygen content of the mixed exhaust gas or a variable correlating thereto is measured and a quantity of fuel supplied to the burner is influenced in such a way that the actual oxygen content at least approaches a target oxygen content of the mixed exhaust gas.

the DE 10 2008 032 601 A1 discloses a method for adjusting a condition of an exhaust flow of an internal combustion engine of a motor vehicle. In this case, an exhaust gas burner is arranged in the exhaust system of the internal combustion engine. In order to enable improved adjustment of the state of the exhaust gas flow, the quantity of fuel injected into the burner and the secondary air supplied to the burner are regulated in such a way that the quantity injected and the secondary air mass flow result in a substoichiometric burner exhaust gas. The burner is used in particular to regenerate a diesel particle filter in the exhaust system.

the DE 10 2017 113 366 A1 describes a method for heating exhaust gas aftertreatment components in the exhaust system of an internal combustion engine before starting the internal combustion engine. An electrically heatable three-way catalytic converter and preferably also a four-way catalytic converter arranged downstream of the three-way catalytic converter are heated in order to enable efficient exhaust aftertreatment of the raw emissions from the internal combustion engine right from the start of the internal combustion engine. The exhaust aftertreatment system is also set up to enable efficient conversion of the pollutants even during regeneration of the four-way catalytic converter and thus to ensure particularly low emissions in all operating states of the internal combustion engine.

The invention is now based on the object of ensuring the highest possible conversion performance of the exhaust gas aftertreatment components in a spark-ignited internal combustion engine in a motor vehicle in all operating states of the motor vehicle.

• - Ermitteln einer Bauteiltemperatur der ersten Abgasnachbehandlungskomponente und einer Konvertierungsleistung der ersten Abgasnachbehandlungskomponente,
• - Ermitteln einer Bauteiltemperatur der zweiten Abgasnachbehandlungskomponente und/oder einer Konvertierungsleitung der zweiten Abgasnachbehandlungskomponente,
• - Vergleichen der Bauteiltemperatur der zweiten Abgasnachbehandlungskomponente mit einer ersten Schwellentemperatur,
• - Ermitteln einer Lastanforderung an den Verbrennungsmotor, und
• - Aktivieren des externen Heizmittels, wenn die ermittelte Bauteiltemperatur der zweiten Abgasnachbehandlungskomponente unterhalb der ersten Schwellentemperatur liegt und die Konvertierungsleistung der ersten Abgasnachbehandlungskomponente bei der ermittelten Lastanforderung an den Verbrennungsmotor voraussichtlich nicht ausreichend ist, um eine vollständige Konvertierung der limitierten Schadstoffe im Abgasstrom des Verbrennungsmotors sicherzustellen.

This object is achieved by a method for treating the exhaust gas of a spark-ignited internal combustion engine in a motor vehicle. The internal combustion engine is connected at its outlet to an exhaust gas aftertreatment system, which has an exhaust system in which a first exhaust gas aftertreatment component, downstream of the first exhaust gas aftertreatment component, an external heating means and further downstream a second exhaust gas aftertreatment component are arranged in the flow direction of an exhaust gas stream of the internal combustion engine through an exhaust gas duct of the exhaust system. The procedure includes the following steps:

• - Determining a component temperature of the first exhaust gas aftertreatment component and a conversion performance of the first exhaust gas aftertreatment component,
• - Determining a component temperature of the second exhaust gas aftertreatment component and/or a conversion line of the second exhaust gas aftertreatment component,
• - comparing the component temperature of the second exhaust aftertreatment component with a first threshold temperature,
• - determining a load requirement on the internal combustion engine, and
• - Activation of the external heating means if the determined component temperature of the second exhaust gas aftertreatment component is below the first threshold temperature and the conversion performance of the first exhaust gas aftertreatment component is not likely to be sufficient for the load demand determined on the internal combustion engine to ensure complete conversion of the limited pollutants in the exhaust gas flow of the internal combustion engine.

The component temperatures of the exhaust gas aftertreatment components can be determined by measuring the temperature in the exhaust system, in particular by a temperature sensor on one of the exhaust gas aftertreatment components, or by a calculation model that calculates the temperature of the exhaust gas aftertreatment components depending on the load on the internal combustion engine and possibly other parameters, in particular the ambient temperature . Such a method makes it possible to bring the exhaust gas aftertreatment components to their respective operating temperature as required and thus to achieve a particularly efficient conversion of the pollutants in the exhaust gas flow of the internal combustion engine. Furthermore, unnecessary heating measures, which would reduce the efficiency of the internal combustion engine and lead to increased consumption, can be avoided. External heating means are to be understood as meaning engine-external heating measures in the exhaust system, ie an external heat input into the exhaust system. The external heating means comprise in particular an exhaust gas burner or an electric heating element.

The additional features listed in the dependent claims allow advantageous improvements and further developments of the method for exhaust gas aftertreatment of the internal combustion engine listed in the independent claim.

In a preferred embodiment of the invention, it is provided that the external heating means is activated immediately after the internal combustion engine is started. Since all exhaust gas aftertreatment components have not yet reached their operating temperature immediately after the engine starts, a large catalytically effective volume can be made available promptly by simultaneously heating up the first exhaust gas aftertreatment component using internal engine heating measures and heating up the second exhaust gas aftertreatment component using external heating means.

In a further preferred embodiment of the invention, it is provided that the external heating means is activated when a current or upcoming higher load requirement on the internal combustion engine is detected. This can prevent emissions from breaking through the first exhaust gas aftertreatment component in the event of a sudden load jump, and these emissions being emitted unconverted into the environment.

Alternatively, an advantageous embodiment of the method provides for the external heating means to be activated when the load requirement on the internal combustion engine falls below a threshold value for a defined time interval. In the case of prolonged low-load operation, the second exhaust aftertreatment component in the underbody position can cool down below its light-off temperature. In order to avoid this, the external heating means is activated during a longer low-load phase in order to keep the second exhaust gas aftertreatment component at a temperature at which efficient conversion of pollutants is possible.

In an advantageous embodiment of the method for exhaust gas aftertreatment, it is provided that the external heating means is activated when the temperature of the second exhaust gas aftertreatment component falls below a second threshold temperature. Alternatively, the external heating means can also be controlled directly by the temperature of the second exhaust gas aftertreatment component if this temperature approaches the light-off temperature and there is a risk that the second exhaust gas aftertreatment component will be ineffective.

A further partial aspect of the invention relates to a motor vehicle with a spark-ignited internal combustion engine, the outlet of which is connected to an exhaust system of an exhaust gas aftertreatment system. In the exhaust system, in the direction of flow of an exhaust gas stream of the internal combustion engine, the exhaust gas is routed through an exhaust gas duct layer a first exhaust gas aftertreatment component, downstream of the first exhaust gas aftertreatment component an external heating means and further downstream a second exhaust gas aftertreatment component. The motor vehicle also has a control unit, in particular an engine control unit, which is set up to execute such a method when a machine-readable program code is executed by the control unit. In such a motor vehicle, particularly effective and energy-efficient exhaust gas aftertreatment of the internal combustion engine is possible.

In a preferred embodiment of the motor vehicle, it is provided that the external heating means is an exhaust gas burner. A comparatively high amount of heat can be introduced into the exhaust system in a short time by an exhaust gas burner, as a result of which the second exhaust gas aftertreatment component heats up particularly quickly. As a result, the period of time until the second exhaust aftertreatment component has reached its light-off temperature can be shortened.

Alternatively or additionally, it is advantageously provided that the external heating means comprises an electrical heating element. An electric heating element enables the temperature in the exhaust system to be regulated particularly precisely. Furthermore, an electric heating element is smaller and cheaper compared to an exhaust gas burner.

It is particularly preferred if the heat output of the external heating means has a heat output of at least 5 KW. With a heat output of at least 5 KW, preferably at least 8 KW, particularly preferably at least 10 KW, the second exhaust gas aftertreatment component can be heated to its light-off temperature in a particularly short time interval. This is particularly useful in the event of an (imminent) load jump, in particular full load acceleration, in order to heat the second exhaust gas aftertreatment component to its light-off temperature before emissions break through through the first exhaust gas aftertreatment component.

In an advantageous embodiment of the motor vehicle, it is provided that the first exhaust gas aftertreatment component and the second exhaust gas aftertreatment component each have a catalytic three-way functionality. A particularly large catalytically active volume can be made available in a simple manner by two exhaust gas aftertreatment components with a catalytic three-way function in order to effectively convert the emissions of the internal combustion engine at each operating point.

In a preferred embodiment of the motor vehicle, it is provided that the motor vehicle has at least one detection means, via which an imminent increase in the load requirement on the internal combustion engine can be identified, with the control unit activating the external heating means when the detection means detects an imminent increase in the load requirement on the internal combustion engine Has. The environment around the motor vehicle and/or the position of the motor vehicle can be determined by detection means. In this case, the detection means include in particular a camera and/or a GPS sensor. In this context, an imminent, probable load requirement on the internal combustion engine can be determined on the basis of the route traveled and/or on the basis of the traffic situation. For example, when driving onto a freeway or at the foot of an incline, it can be recognized that a high load requirement is imminent and the second exhaust gas aftertreatment component is heated by the external heating means before the corresponding load requirement is placed on the internal combustion engine. In this way, the emissions from the internal combustion engine can be reduced particularly effectively.

Unless stated otherwise in the individual case, the various embodiments of the invention mentioned in this application can advantageously be combined with one another.

• 1 eine schematische Darstellung eines Kraftfahrzeuges,
• 2 eine schematische Darstellung eines Verbrennungsmotors mit einem Abgasnachbehandlungssystem;
• 3 eine alternative Ausgestaltung eines Verbrennungsmotors mit einem Abgasnachbehandlungssystem in schematischer Darstellung;
• 4 eine weitere alternative Ausgestaltung eines Verbrennungsmotors mit einem Abgasnachbehandlungssystem in schematischer Darstellung; und
• 5 ein Ablaufschema zur Durchführung eines erfindungsgemäßen Verfahrens zur Abgasnachbehandlung eines Verbrennungsmotors in einem Kraftfahrzeug.

The invention is explained below in exemplary embodiments with reference to the associated drawings. Identical components or components with the same function are identified in the different figures with the same reference numbers. Show it:

• 1 a schematic representation of a motor vehicle,
• 2 a schematic representation of an internal combustion engine with an exhaust gas aftertreatment system;
• 3 an alternative embodiment of an internal combustion engine with an exhaust gas aftertreatment system in a schematic representation;
• 4 a further alternative embodiment of an internal combustion engine with an exhaust gas aftertreatment system in a schematic representation; and
• 5 a flow chart for carrying out a method according to the invention for the exhaust aftertreatment of an internal combustion engine in a motor vehicle.

1 shows a motor vehicle 1 with an internal combustion engine 10. The internal combustion engine 10 is designed as a spark-ignited internal combustion engine 10 according to the Otto principle and has a plurality of combustion chambers 12, on each of which a fuel injector 14 and a spark plug 16 are arranged. The internal combustion engine 10 is connected with its outlet 18 to an exhaust system 22 of an exhaust gas aftertreatment system 20 . The motor vehicle 1 has at least one detection means 76, preferably a plurality of detection means 76, with which the surroundings of the motor vehicle, the position of the motor vehicle, the direction of travel, the speed, the environment and possibly other parameters can be detected. The detection means 76 can in particular include a GPS sensor 66 for detecting the position and change in position of the motor vehicle 1 . The detection means 76 can also include one or more optical detection means 76, in particular one or more camera(s) 68. The detection means 76 are connected to a data transfer unit 70, which processes the information from the detection means and exchanges it with other vehicle-internal or vehicle-external data sources, in particular a driver assistance system of the motor vehicle 1, a navigation system or an external data center. For this purpose, the motor vehicle 1 has a transmitting unit 62 and a receiving unit 64 . The transmission unit 62 and the reception unit 64 can also be integrated in one component.

2 shows a schematic representation of an internal combustion engine 10, which is connected to an exhaust system 22 with its outlet 18. The internal combustion engine 10 is preferably designed as an Otto engine with direct gasoline injection and has a plurality of combustion chambers 12, on each of which a fuel injector 14 for injecting a fuel into the respective combustion chamber 12 is arranged. Furthermore, a spark plug 16 is assigned to each combustion chamber 12 in order to ignite an ignitable fuel-air mixture in the respective combustion chamber 12 of the internal combustion engine 10 .

Internal combustion engine 10 has an exhaust aftertreatment system 20 with an exhaust system 22 . Exhaust system 22 includes an exhaust gas duct 24, in which, in the direction of flow of an exhaust gas flow from internal combustion engine 10 through exhaust gas duct 24, is a turbine 28 of an exhaust gas turbocharger 26, downstream of turbine 28 a first exhaust gas aftertreatment component 30, in particular a first three-way catalytic converter 44, downstream of the first Exhaust gas aftertreatment component 30, an external heating means 36, in particular an exhaust gas burner 38, and further downstream a second exhaust gas aftertreatment component 32, in particular a second three-way catalytic converter 46, are arranged. The first exhaust gas aftertreatment component 30 is arranged as an exhaust gas aftertreatment component 72 close to the engine and the second exhaust gas aftertreatment component 32 as an exhaust gas aftertreatment component in an underbody position 74 of the motor vehicle 1 . A first temperature sensor 52 is arranged on first exhaust gas aftertreatment component 30 . The second exhaust aftertreatment component 32 has a second temperature sensor 54 . An exhaust gas sensor 58 , in particular a sensor for detecting a pollutant concentration in the exhaust gas duct 24 , is arranged downstream of the second exhaust gas aftertreatment component 32 . Alternatively, the internal combustion engine 10 can also be designed as a naturally aspirated engine, in which case the exhaust gas turbocharger 26 with the turbine 28 is omitted. Alternatively, one of the two exhaust gas aftertreatment components 30, 32 can be designed as a four-way catalytic converter 50 in order to filter particles from the exhaust gas flow of the internal combustion engine 10 in addition to the catalytic function. An introduction point 40 is formed on the exhaust gas duct 24 , at which the exhaust gas from the exhaust gas burner 38 can be introduced into the exhaust gas duct 24 of the internal combustion engine 10 . As an alternative to an exhaust gas burner 38, the external heating means 36 can also be used as in 4 shown as an electric heating element 42 .

In 3 An alternative exemplary embodiment of an internal combustion engine 10 with an exhaust gas aftertreatment system 20 is illustrated. With essentially the same structure as 2 executed, downstream of the first exhaust gas aftertreatment component 30 is another exhaust gas aftertreatment component close to the engine 34 , 72 . This additional exhaust gas aftertreatment component can be a gasoline particle filter 48 in particular. In this case, the external heating means 36 or the introduction point 40 of the exhaust gas burner 38 is located downstream of the further exhaust gas aftertreatment component 34 and upstream of the second exhaust gas aftertreatment component 32, which is arranged in an underbody position of the motor vehicle 1. As an alternative to an Otto particle filter 48, the additional exhaust gas aftertreatment component 34 can also be designed as an additional catalytic converter.

In 4 Another alternative exemplary embodiment of an internal combustion engine 10 with an exhaust gas aftertreatment system 20 is illustrated. With essentially the same structure as 2 and 3 described, the in 4 Exhaust gas aftertreatment system 20 shown has a close-coupled exhaust gas aftertreatment component 72 and two exhaust gas aftertreatment components 32, 34, 74 in the underbody position. The first exhaust gas aftertreatment component 30 , 72 close to the engine is preferably designed as a three-way catalytic converter 44 guided. The two exhaust gas aftertreatment components 32, 34, 74 in the underbody position are preferably designed as a second three-way catalytic converter 46 and as a gasoline particulate filter 48, with the order in which the second three-way catalytic converter 46 and the gasoline particulate filter 48 flow through being arbitrary. The external heating means 36 is in 4 designed as an electric heating element 42, but alternatively, as in 2 or 3 shown at the same place an exhaust gas burner 38 can be provided.

The aim of the method for exhaust gas aftertreatment according to the invention is to provide the highest possible conversion performance as required under all driving conditions of the motor vehicle 1 in the entire driving cycle. By heating an exhaust gas aftertreatment component 32, 74 remote from the engine in the underbody position, a larger catalytically active volume is provided for converting the emissions than if the exhaust gas aftertreatment components were only heated by internal engine heating measures.

Depending on the state of the two exhaust gas aftertreatment components 30, 32 and other conditions, the method decides whether heating the second exhaust gas aftertreatment component 32, preferably the exhaust gas aftertreatment component in the underbody layer 74, makes sense. In this way, an energetically unnecessary overheating of the second exhaust gas aftertreatment component 32 can be prevented at the same time and a constantly high conversion performance of the exhaust gas aftertreatment system 20 can be ensured.

Starting from an engine start of the internal combustion engine 10, the exhaust gas aftertreatment system 20 can be heated to its operating temperature by the external heating means 36 in parallel to internal engine heating measures, which predominantly cause rapid heating of the first exhaust gas aftertreatment component. This leads to a reduction in emissions. If the second exhaust gas aftertreatment component 32, in particular a second three-way catalytic converter 46, is at operating temperature, the external heating means 36 can be deactivated. If the second exhaust gas aftertreatment component 32 cools down again during the further operation of the motor vehicle 1 and it is foreseeable, depending on various operating parameters of the internal combustion engine 10 or by a signal from a detection means 76, that a high conversion output is required, the external heating means 36 can be activated again in order to second exhaust gas aftertreatment component 32 to at least heat up again to its light-off temperature. Influencing variables in this context can be, in particular, the temperatures of the exhaust gas aftertreatment components 30, 32, the exhaust gas mass flow of the internal combustion engine 10, the aging condition of the exhaust gas aftertreatment components 30, 32, the exhaust gas temperature, the ambient temperature and the power or torque demand on the internal combustion engine 10.

The heating measure by the external heating means 36 is particularly suitable for starting the engine of the internal combustion engine 10 in which all exhaust gas aftertreatment components 30, 32, 34 are not yet at operating temperature. In this context, a temperature of at least 350° C. is regarded as the operating temperature for catalytic converters. The heating measure by the external heating means 36 is also suitable for bringing an exhaust gas aftertreatment component in the underbody layer 74, in particular a three-way catalytic converter 46, back to its operating temperature after prolonged low-load operation. The relevant component temperatures can be determined by temperature sensors 52, 54, 56 or calculated in control unit 60 on the basis of a temperature model.

In 5 a flowchart of a method according to the invention for exhaust gas aftertreatment is shown. In a method step <100> it is checked whether internal combustion engine 10 is active. If the internal combustion engine 10 is not active, the method is aborted in a method step <105> and the external heating means 36 is not activated. If internal combustion engine 10 is active, a method step <110> checks whether temperature T _ANK2 of second exhaust gas aftertreatment components 32, 74 in the underbody position is lower than a first threshold temperature T _S1 . If the temperature of the second exhaust gas aftertreatment component T _ANK2 is higher than this first threshold temperature T _S1 , the method is ended in a method step <115> and the external heating means 36 is not activated or switched off. If the temperature of the second exhaust gas aftertreatment component T _{ANK2 is} lower than this first threshold temperature T _S1 , a method step <120> checks whether the temperature T _ANK1 of the first exhaust gas aftertreatment component 30, 72 close to the engine is lower than its light-off temperature. If the temperature T _ANK1 is higher than its light-off temperature, in a method step <125> it is checked whether the load requirement on the internal combustion engine 10 is higher than a threshold load at which sufficient conversion of the pollutants by the first exhaust gas aftertreatment component 30 is possible. If this is not the case, the method is aborted again in method step <115>. Is the load request higher than this threshold load or is the temperature T _ANK1 of the first exhaust aftertreatment component If the temperature is lower than its light-off temperature, the external heating means 36 is activated in a method step <130> in order to heat the second exhaust gas aftertreatment component 32 at least up to its light-off temperature, preferably up to its operating temperature.

If the detection means recognizes that a high power demand on the internal combustion engine 10, in particular a full load acceleration, is imminent, then the external heating means 36 is also activated if the conversion capacity of the first exhaust gas aftertreatment component 30 is currently still sufficient to completely reduce the emissions of the internal combustion engine 10 convert. It can thus be prevented that the first exhaust gas aftertreatment component 30 is “run over” during a full-load acceleration and then insufficient catalytic volume is available to convert the additional pollutants. A typical forthcoming full-load acceleration can be assumed, for example, when driving onto a freeway. This can be detected by the detection means 76 described, in particular by the GPS sensor 66 and/or the camera 68 .

Reference List

1

motor vehicle

10

combustion engine

12

combustion chamber

14

fuel injector

16

spark plug

18

outlet

20

exhaust aftertreatment system

22

exhaust system

24

exhaust duct

26

exhaust gas turbocharger

28

turbine

30

first exhaust aftertreatment component

32

second exhaust aftertreatment component

34

third exhaust aftertreatment component

36

external heating medium

38

exhaust burner

40

discharge point

42

electric heating element

44

first three-way catalytic converter

46

second three-way catalytic converter

48

gasoline particulate filter

50

Four-way catalytic converter

52

first temperature sensor

54

second temperature sensor

56

third temperature sensor

58

exhaust gas sensor

60

engine control unit

62

transmitter unit

64

receiving unit

66

GPS sensor

68

camera

70

data transfer unit

72

close-coupled exhaust aftertreatment component

74

Exhaust aftertreatment component in underbody position

76

detection means

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely 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 102012021573 A1 [0003]
• DE 102008032601 A1 [0004]
• DE 102017113366 A1 [0005]

Claims (10)

Method for exhaust gas aftertreatment of a spark-ignited internal combustion engine (10) of a motor vehicle (1) with an exhaust gas aftertreatment system (20) which has an exhaust system (22) in which, in the flow direction of an exhaust gas flow from the internal combustion engine (10), through an exhaust gas duct (24) of the exhaust system (22 ) a first exhaust gas aftertreatment component (30), downstream of the first exhaust gas aftertreatment component (30) an external heating means (36) and further downstream a second exhaust gas aftertreatment component (32) is arranged, comprising the following steps: - determining a component temperature (T _ANK1 ) of the first exhaust gas aftertreatment component (30 ) and a conversion performance of the first exhaust gas aftertreatment component (30), - determining a component temperature (T _ANK2 ) of the second exhaust gas aftertreatment component (32) and/or a conversion line of the second exhaust gas aftertreatment component (32), - comparing the component temperature (T _ANK2 ) of the second exhaust gas aftertreatment s component (32) with a first threshold temperature (T _S1 ), - determining a load requirement on the internal combustion engine (10), and - activating the external heating means (36) if the determined component temperature (T _ANK2 ) of the second exhaust gas aftertreatment component (32) below the first threshold temperature (T _S ) and the conversion performance of the first exhaust gas aftertreatment component (30) is probably not sufficient for the determined load requirement on the internal combustion engine (10) to ensure complete conversion of the limited pollutants in the exhaust gas flow of the internal combustion engine (10). Process for exhaust aftertreatment claim 1 , characterized in that the external heating means (36) is activated immediately after an engine start of the internal combustion engine (10). Process for exhaust aftertreatment claim 1 or 2 , characterized in that the external heating means (36) is activated when a current or upcoming higher load requirement on the internal combustion engine (10) is detected. Process for exhaust gas aftertreatment according to one of Claims 1 until 3 , characterized in that the external heating means (36) is activated when the load requirement on the internal combustion engine (10) for a defined time interval (Δt) falls below a threshold value (P _S ). Process for exhaust gas aftertreatment according to one of Claims 1 until 4 , characterized in that the external heating means (36) is activated when the temperature of the second exhaust gas aftertreatment component (T _ANK2 ) falls below a second threshold value (T _S2 ). Motor vehicle (1) with a spark-ignited internal combustion engine (10), the internal combustion engine (10) being connected by its outlet (18) to an exhaust system (22) of an exhaust gas aftertreatment system (20), in which in the flow direction of an exhaust gas stream of the internal combustion engine (10) through an exhaust gas duct (24) of the exhaust system (22), a first exhaust gas aftertreatment component (30), downstream of the first exhaust gas aftertreatment component (30) an external heating means (36) and further downstream a second exhaust gas aftertreatment component (32) are arranged, and with a control unit (60), which is set up to use a method according to one of Claims 1 until 5 to be carried out when a machine-readable program code is executed by the control unit (60). Motor vehicle (1) after claim 6 , characterized in that the external heating means (36) is an exhaust gas burner (38) or an electric heating element (42). Motor vehicle (1) after claim 7 , characterized in that the external heating means (36) has a heating capacity of at least 5 kW. Motor vehicle (1) according to one of Claims 6 until 8th , characterized in that the first exhaust gas aftertreatment component (30) and the second exhaust gas aftertreatment component (32) each have a catalytic three-way functionality. Motor vehicle (1) according to one of Claims 6 until 9 , characterized in that the motor vehicle (1) has at least detection means (76) via which an imminent increase in the load requirement on the internal combustion engine (10) can be identified, the control unit (60) activating the external heating means when the detection means (76) has detected an impending increase in the load requirement on the internal combustion engine (10).

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