DE102020006451A1 - Control device for controlling a hydrogen content of an exhaust gas from an internal combustion engine - Google Patents

Abstract

The invention relates to a control device for a drive train, comprising an internal combustion engine, for controlling the internal combustion engine, so that a hydrogen content of an exhaust gas is adjusted.
The control device (1) according to the invention for a drive train (2), comprising an internal combustion engine (3) and an exhaust gas aftertreatment system (4), the internal combustion engine (3) being designed as a hydrogen engine and the exhaust gas aftertreatment system (4) comprising a first DeNOx system (5) , is trained and equipped to perform the following steps:
- Detecting a content (S10) of a component of an exhaust gas upstream or downstream of the first DeNOx system (5) and
- Controlling (S40) the internal combustion engine (3) so that an H2 content of the exhaust gas is adjusted based on the detected content (S10).

Description

The invention relates to a control device for a drive train, comprising an internal combustion engine, for controlling the internal combustion engine, so that a hydrogen content of an exhaust gas is adjusted.

From the DE 10 2007 021 827 A1 An exhaust gas purification system for a hydrogen engine is known, wherein hydrogen gas is introduced into the exhaust gas based on a detection of an exhaust gas element upstream of a catalyst of the exhaust gas purification system in order to improve a purification of the exhaust gas element.

• - Erfassen eines Gehalts einer Komponente eines Abgases stromauf oder stromab des ersten DeNOx Systems und
• - Steuern des Verbrennungsmotors, so dass ein Gehalt an Wasserstoff (H2) des Abgases basierend auf dem erfassten Gehalt angepasst wird.

The control device according to the invention for a drive train, comprising an internal combustion engine and an exhaust gas aftertreatment system, wherein the internal combustion engine is designed as a hydrogen engine and the exhaust gas aftertreatment system comprises a first DeNOx system, is designed and set up to carry out the following steps:

• - Detecting a content of a component of an exhaust gas upstream or downstream of the first DeNOx system and
• - Controlling the internal combustion engine so that a content of hydrogen ( H2 ) of the exhaust gas is adjusted based on the recorded content.

Because the control unit controls the internal combustion engine in such a way that an H2 content of the exhaust gas is adapted based on the detected content, the invention enables an H2 content required for exhaust gas cleaning by the first DeNOx system to be provided. This has the advantage that the H2 content of the exhaust gas can be adjusted without the need for an additional metering device in order to provide hydrogen upstream of the first DeNOx system.

A DeNOx system is understood to be a system for reducing NOx emissions. This can be an SCR catalytic converter or a NOx storage catalytic converter, for example.

Detection is understood here to mean both a measurement with the aid of a sensor arranged upstream and / or downstream of the first DeNOx system and, alternatively or additionally, a calculation of the content of the component of the exhaust gas with the aid of a model and / or a characteristic map. A NOx or H2 probe, for example, but also a lambda probe can be used as the sensor.

The control device preferably detects a hydrogen content upstream of the first DeNOx system. By comparing with a required hydrogen content stored in a map, for example, the control unit controls the internal combustion engine to adjust the hydrogen content.

As an alternative or in addition, the control unit records a content of nitrogen oxides (NOx) downstream of the first DeNOx system. By comparing with a target value for nitrogen oxide emissions, the control unit causes the internal combustion engine to be controlled so that the hydrogen content of the exhaust gas is adapted.

Controlling is understood here to be a control with an open or temporarily closed action path as well as a regulation with a closed action sequence.

• - Erfassen eines ersten Gehalts einer Komponente eines Abgases stromauf des ersten DeNOx Systems,
• - Erfassen eines zweiten Gehalts der Komponente des Abgases stromab des ersten DeNOx Systems,
• - Vergleichen des ersten und des zweiten erfassten Gehalts der Komponente und
• - Steuern des Verbrennungsmotors, so dass ein H2 Gehalt des Abgases basierend auf dem Ergebnis des Vergleichens angepasst wird.

The control device is preferably designed and set up to carry out the following steps:

• - Detecting a first content of a component of an exhaust gas upstream of the first DeNOx system,
• - Detecting a second content of the component of the exhaust gas downstream of the first DeNOx system,
• - Comparing the first and the second detected content of the component and
• - Controlling the internal combustion engine, so that an H2 content of the exhaust gas is adjusted based on the result of the comparison.

Because the control unit controls the internal combustion engine in such a way that an H2 content of the exhaust gas is adjusted based on the result of the comparison, the invention enables an H2 content required for exhaust gas cleaning by the first DeNOx system to be set, taking into account a change in the content of the component can be provided via the first DeNOx system.

The control device preferably detects a first and a second NOx content of the exhaust gas. Based on the comparison of the first and the second NOx content, the control unit can determine a NOx conversion rate of the first DeNOx system. If the NOx conversion rate is too low, the internal combustion engine can be controlled in such a way that an H2 content of the exhaust gas is adjusted.

The control device particularly preferably detects the second NOx content by means of a sensor arranged downstream of the first DeNOx system and the first NOx content by means of a model. This saves a sensor and reduces costs. The downstream of the first DeNOx system arranged sensor can be designed, for example, as a NOx probe or lambda probe.

Too low is understood here to be a NOx conversion rate of less than 85%, preferably less than 90%, particularly preferably less than 95%.

The internal combustion engine is preferably designed as a direct-injection hydrogen engine and the control unit is designed and set up to supply hydrogen to the internal combustion engine in an exhaust stroke of the internal combustion engine when controlling the internal combustion engine, so that the H2 content of the exhaust gas is adjusted based on the detected content or based on the result of the comparison can.

Because the control unit causes hydrogen to be supplied in the exhaust stroke of the internal combustion engine, the invention enables the H2 content of the exhaust gas to be adapted based on the detected content or based on the result of the comparison without a significant change in the combustion process.

Supplying hydrogen in the exhaust cycle means that the hydrogen is introduced into the cylinder well after top dead center, but before an exhaust valve of a cylinder of the internal combustion engine is opened. As a result, the hydrogen introduced in this way does not take part in chemical reactions or takes part only very little and is largely unburned in the exhaust gas.

The control unit is preferably designed and set up to control a fuel-air ratio, an ignition point, an injection point, an EGR rate and / or an inlet pressure when controlling the internal combustion engine.

Since the control unit controls a fuel-air ratio, an ignition point, an injection point, an EGR rate and / or an intake pressure during control, the invention enables a combustion sequence to be adapted in such a way that the H2 content is based on the recorded salary or can be adjusted based on the result of the comparison.

The internal combustion engine preferably comprises a spark plug for igniting the hydrogen-air mixture. In this way, reliable ignition can be achieved and, by adapting the ignition point, a combustion center and thus also an H2 emission can be influenced directly.

The control device is preferably designed and set up to take into account a knock limit, a combustion center of gravity, a load requirement and / or a NOx emission of the internal combustion engine when controlling.

Because the control unit takes into account a knock limit, a combustion center of gravity, a load requirement and / or NOx emission of the internal combustion engine when controlling, the invention enables knocking combustion to be avoided or at least reduced the probability of knocking combustion to occur, a desired performance to be provided and fuel consumption and NOx emissions can be limited.

The control device can preferably control a ratio of a content between H2 and NOx, so that sufficient H2 is present in the exhaust gas to reduce NOx emissions in the first DeNOx system that arise in the internal combustion engine. The H2 / NOx ratio in the exhaust gas is particularly preferably greater than or equal to seven.

The first DeNOx system preferably comprises a metering unit, the metering unit being designed and set up to supply a reducing agent containing H2 or NH3 to the exhaust gas aftertreatment system. The control device is designed and set up to cause the reducing agent to be supplied by the metering unit.

By causing the control device to feed the reducing agent through the metering unit, a hydrogen content in the exhaust gas can be adapted without intervention in the control of the internal combustion engine based on the detected content or based on the result of the comparison.

The control device preferably only initiates a supply of the reducing agent if controlling the internal combustion engine is insufficient to adjust the H2 content of the exhaust gas, and / or if supplying the reducing agent is more favorable than controlling the internal combustion engine for energy reasons or with regard to emissions to be considered is.

Furthermore, the metering unit is preferably designed and set up to introduce the reducing agent at at least two positions in relation to the cross-sectional area of the exhaust gas aftertreatment system, so that mixing of reducing agent and exhaust gas can be improved. The exhaust gas aftertreatment system also preferably comprises a mixer downstream of the metering unit, so that mixing of the reducing agent and exhaust gas can be improved.

The first DeNOx system is preferably designed as an H2-SCR system or as an NH3-SCR system.

Because the first DeNOx system is designed as an H2-SCR system or as an NH3-SCR system, NOx emissions can be reduced by the exhaust gas aftertreatment system.

If the first DeNOx system is designed as an NH3-SCR system, it preferably comprises a three-way catalytic converter or a NOx storage catalytic converter. This has the advantage that emissions of unburned hydrocarbons and NOx emissions contained in the exhaust gas can be converted in the three-way catalytic converter or in the NOx storage catalytic converter, if the latter is regenerated, with the formation of NH3. The NH3 can be used in the NH3-SCR system to reduce NOx emissions or stored in the NH3-SCR system for a later reduction of NOx emissions. This enables the NH3-SCR system to be implemented as a passive SCR system, i.e. without a dosing device.

Furthermore, the exhaust gas aftertreatment system preferably comprises a second DeNOx system, the second DeNOx system being arranged downstream of the first DeNOx system. This has the advantage that sufficient NOx conversion can be achieved even at operating points with very high NOx emissions.

The first DeNOx system is particularly preferably designed as an H2-SCR system and the second SCR system as an NH3-SCR system. This has the advantage that NOx conversion can be made possible over a large temperature range, since the NH3-SCR system has sufficient NOx conversion rates in a different temperature range than the H2-SCR system.

The dependent claims describe further advantageous embodiments of the invention.

• 1 ein Ausführungsbeispiel eines Antriebstrangs mit einem Steuergerät,
• 2 ein Ausführungsbeispiel von durch ein Steuergerät ausgeführten Schritten zum Steuern eines H2 Gehalts im Abgas,
• 3 ein Ausführungsbeispiel eines Abgasnachbehandlungssystems eines Antriebsstrangs und
• 4 ein weiteres Ausführungsbeispiel ein Abgasnachbehandlungssystem eines Antriebsstrangs

Preferred exemplary embodiments are explained in more detail with reference to the following figures. It shows

• 1 an embodiment of a drive train with a control unit,
• 2 an embodiment of steps carried out by a control unit for controlling an H2 content in the exhaust gas,
• 3 an embodiment of an exhaust gas aftertreatment system of a powertrain and
• 4th Another exemplary embodiment is an exhaust gas aftertreatment system for a drive train

1 shows a powertrain 2 for a vehicle. The powertrain 2 includes an intake section 9 , an internal combustion engine 3 , an exhaust line 10 as well as a first 11 and a second 12th Exhaust gas recirculation line. Here is the intake section 9 upstream of the internal combustion engine 3 arranged. The exhaust line 10 is downstream of the internal combustion engine 3 arranged and includes an exhaust gas purification system 4th .

The internal combustion engine 3 is a supercharged, direct-injection and spark-ignited hydrogen engine with four cylinders 13th executed. This includes the internal combustion engine 3 an exhaust gas turbocharger 14th . The exhaust gas turbocharger 14th includes one in the intake section 9 arranged compressor 15th and one in the exhaust line 10 arranged turbine 16 . The turbine 16 and the compressor 15th are coupled together so that the through the turbine 16 Energy absorbed by the exhaust gas from the compressor 15th can be used to compress the fresh gas to an increased pressure level.

For introducing the hydrogen into the cylinders 13th includes the internal combustion engine 3 an injector 30th . The injector 30th includes one injector per cylinder 13th , Supply lines and a fuel supply.

The internal combustion engine comprises an ignition device for igniting the hydrogen-air mixture 40 . The ignition device 40 includes one spark plug per cylinder 13th and an ignition system connected to the spark plugs.

The exhaust gas cleaning system 4th includes an H2-SCR catalytic converter 5 , an NH3-SCR system and an ammonia slip catalyst (ASC) 7th . The H2-SCR catalytic converter 5 is trained to reduce nitrogen oxide emissions using H2.

The NH3-SCR system is downstream of the H2-SCR catalytic converter 5 arranged and comprises an NH3-SCR catalyst 6th , a dosing unit 19th and a mixer 20th . The dosing unit 19th is designed and installed ammonia (NH3) upstream of the NH3-SCR catalytic converter 6th into the exhaust line 10 bring in. In the one between the dosing unit 19th and the NH3-SCR catalyst 6th arranged mixer 20th the introduced ammonia and the exhaust gas are mixed. The NH3-SCR catalyst 6th is trained and set up to reduce NOx emissions using ammonia.

A NOx sensor is used to record NOx emissions 22nd downstream of the exhaust aftertreatment system 4th arranged.

The first exhaust gas recirculation section 11 is upstream of the emission control system 4th arranged and formed, exhaust gas upstream of the turbine 16 of the exhaust gas turbocharger 14th from the exhaust line 10 discharge and the intake section 9 downstream of the compressor 15th of the exhaust gas turbocharger 14th to feed. The second exhaust gas recirculation line 12th is designed, exhaust gas downstream of the H2-SCR system 5 from the exhaust line 10 discharge and upstream of the compressor 15th of the exhaust gas turbocharger 14th the intake section 9 to feed. With the first 11 and the second 12th Exhaust gas recirculation can be used for the operation of the internal combustion engine 3 preferred exhaust gas recirculation rates provided and the most efficient possible operation of the internal combustion engine 3 can be achieved.

• - Erfassen eines ersten NOx Gehalts S10 des Abgases stromauf des Abgasnachbehandlungssystems 4 mittels eines Modells,
• - Erfassen eines zweiten NOx Gehalts S20 des Abgases stromab des Abgasnachbehandlungssystems 4 mittels des NOx Sensors 22,
• - Vergleichen des ersten und des zweiten erfassten S10,S20 NOx Gehalts und
• - Steuern S40 des Verbrennungsmotors 3, so dass ein H2 Gehalt des Abgases basierend auf dem Ergebnis des Vergleichens S30 angepasst wird.

The powertrain 2 includes a control unit 1 . The control unit 1 is designed and set up to execute a control program. The control program includes commands to perform the following steps:

• - Detecting a first NOx content S10 of the exhaust gas upstream of the exhaust aftertreatment system 4th by means of a model,
• - Detecting a second NOx content S20 of the exhaust gas downstream of the exhaust aftertreatment system 4th by means of the NOx sensor 22nd ,
• - Compare the first and the second detected S10 , S20 NOx content and
• - Taxes S40 of the internal combustion engine 3 so that an H2 content of the exhaust gas based on the result of the comparison S30 is adjusted.

For recording the first NOx content S10 the control program includes commands to execute the model. The model is designed to determine a NOx content of the exhaust gas at an outlet of the internal combustion engine 3 (engine-out NOx).

For recording the second NOx content S20 the control program includes commands, measurement data from the NOx sensor 22nd read in and process.

To compare S30 the control program comprises commands based on the detected first NOx content S10 and the detected second NOx content S20 a NOx conversion rate for the NH3-SCR system 6th and the H2-SCR catalytic converter 5 to determine.

To steer S40 of the internal combustion engine 3 The control program includes commands to adjust a fuel-air ratio, an ignition point and an intake pressure, or to adjust hydrogen in an exhaust stroke of the internal combustion engine 3 the cylinders 13th so that the H2 content of the exhaust gas based on the result of the comparison S30 is adjusted. The H2 contained in the exhaust gas is then used in the H2-SCR catalytic converter to reduce NOx emissions.

If the comparison shows, for example, that the H2 content needs to be increased, the control program adjusts the fuel / air ratio, the ignition point and / or the inlet pressure accordingly. Characteristic maps are stored in the control program for adjustment. In alternative exemplary embodiments, measurement data and / or a model are used additionally or alternatively for the adaptation.

The control program includes commands, when adjusting a knock limit, a combustion center of gravity and a load requirement of the internal combustion engine 3 as well as the resulting NOx emissions, so that knocking combustion is avoided as far as possible, the necessary power is provided with the lowest possible fuel consumption and NOx emissions are limited.

If controlling the fuel-air ratio, the ignition point and the inlet pressure is not sufficient to provide a desired H2 content in the exhaust gas and / or cannot be sensibly implemented for energy reasons or emission requirements, the control program initiates an injection of hydrogen in an exhaust cycle cylinder 13th so that the injected hydrogen is largely present in the exhaust gas without participating in chemical reactions.

When operating the internal combustion engine 3 with a high load, the control program includes commands, ammonia via the dosing unit 19th into the exhaust line 10 upstream of the NH3-SCR catalyst 6th bring in. Using the NH3, the NH3-SCR catalytic converter reduces 6th NOx emissions in the exhaust gas. In this way, NOx emissions can occur over a large operating range of the internal combustion engine 3 can be effectively reduced.

3 Figure 3 shows an alternative embodiment of the exhaust aftertreatment system 4th . Here the NH3-SCR system is designed as a passive system and only includes the NH3 catalytic converter 6. However, there is a NOx storage catalytic converter (NSK) upstream of the NH3 catalytic converter. 8th arranged.

The NSK is designed to adsorb emissions of nitrogen oxides (NOx) and to reduce them in a regeneration mode with the formation of NH3. The NH3-SCR catalyst 6th can do that from NSK 8th Store formed NH3 and direct or to at a later date to reduce nitrogen oxide emissions.

Upstream of the NSK 8th includes the exhaust aftertreatment system 4th a dosing unit 19th and a mixer. The dosing unit 19th is designed and set up here, H2 in the exhaust system 10 bring in. The control program initiates this at operating points of the internal combustion engine 3 , in which the H2 content in the exhaust gas upstream of the NSK 8th is not high enough to have sufficient quantities of NH3 in the NSK 8th to form H2 to be added to NOx emissions in the NH3-SCR catalytic converter 6th to reduce.

4th shows a further, alternative embodiment of the exhaust gas aftertreatment system 4th . In this exemplary embodiment, the exhaust aftertreatment system is 4th between the H2-SCR catalytic converter 5 and the double-flow NH3-SCR system with a first one 51 and a second 52 Exhaust gas flood executed. This includes the exhaust aftertreatment system 4th a locking device 53 so that one the first 51 and the second exhaust gas flow 52 exhaust gas flow flowing through is controllable.

The first 51 and the second 52 Exhaust gas floods each include a NOx storage catalytic converter 8th . The dosing unit 19th is designed and set up here, the first and / or the second exhaust gas flow H2 to be supplied as a reducing agent.

The locking device 53 is trained and established, the first 51 and the second 52 To close the exhaust gas flow at least partially by a slide. At least one of the two exhaust gas flows 51 , 52 remains fully open.

In 4th is the second exhaust gas flow 52 fully open. The NSK 8th in the second exhaust gas flow 52 stores NOx emissions in a temperature range of approximately 200 - 500 ° C. As the level of the NSK rises 8th its efficiency is reduced and it has to be regenerated by reducing the NOx.

For the regeneration of a NOx storage catalytic converter 8th causes the control program to close the corresponding exhaust gas flow 51 , 52 through the locking device 53 . In 4th is this for the first flood of exhaust gases 51 shown. In addition, the control program causes the metering unit to introduce hydrogen 19th . The hydrogen is in the NSK 8th implemented during regeneration with the formation of NH3.

The exhaust aftertreatment system 4th includes a metering line 54 , which is designed, the introduced hydrogen from the metering unit 19th to the first 51 and / or second 52 To lead exhaust gas flood. The H2 dosing line 54 is designed for this in such a way that a pressure drop from a pressure at a first point P1 to a print at a second point P2 is sufficient, a light flush flow of exhaust gas with the metered H2 in the direction of the NSK to be regenerated 8th to lead so that part of the hydrogen can be oxidized with the oxygen in the exhaust gas. The oxidation of the hydrogen releases heat, which causes the NSK to be regenerated to cool down 8th can be avoided or at least reduced.

That with the regeneration in the NSK 8th NH3 formed is in the downstream NH3-SCR catalytic converter 6th used for NOx reduction. This in 4th The exemplary embodiment shown of the exhaust gas aftertreatment system enables an amount of NH3 to be set by means of the hydrogen metering.

The control program can control the closing device 53 position so that the first 51 and the second 52 Exhaust gas flow are fully open. By introducing hydrogen through the dosing unit 19th over the dosing line 54 can both NSK's 8th be regenerated. This operation is particularly advantageous when operating the internal combustion engine at medium loads.

In a further, alternative embodiment, the NH3-SCR system 6th a three-way catalytic converter. In the three-way catalytic converter, emissions of CO, HC and NOx are reduced, with NH3 also being reduced, in particular in the event of deviations from stoichiometric operation of the internal combustion engine 3 is formed. The NH3 is in the NH3-SCR system 6th stored and used directly or at a later point in time to reduce nitrogen oxide emissions.

In further, alternative exemplary embodiments, the exhaust gas aftertreatment system comprises a particle filter and / or an oxidation catalytic converter. The particulate filter enables the reduction of soot emissions, the oxidation catalytic converter enables the reduction of unburned hydrocarbons and carbon monoxide in the exhaust gas. In one embodiment, the particle filter is designed with an oxidation coating.

In further, alternative exemplary embodiments, the H2-SCR is a catalytic converter 5 , the NH3-SCR catalyst 6th or the ASC 7th designed as a particle filter with a corresponding coating.

QUOTES INCLUDED IN THE DESCRIPTION

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Patent literature cited

• DE 102007021827 A1 [0002]

Claims (12)

Control unit (1) for a drive train (2), comprising an internal combustion engine (3) and an exhaust gas aftertreatment system (4), the internal combustion engine (3) being designed as a hydrogen engine, the exhaust gas aftertreatment system (4) comprising a first DeNOx system (5) and wherein the control device (1) is designed and set up to carry out the following steps: - Detecting a content (S10) of a component of an exhaust gas upstream or downstream of the first DeNOx system (5) and - Controlling (S40) the internal combustion engine (3) so that an H2 content of the exhaust gas is adjusted based on the detected content (S10). Control unit (1) for a drive train (2), comprising an internal combustion engine (3) and an exhaust gas aftertreatment system (4), the internal combustion engine (3) being designed as a hydrogen engine, the exhaust gas aftertreatment system (4) comprising a first DeNOx system (5) and wherein the control device (1) is designed and set up to carry out the following steps: - Detecting a first content (S10) of a component of an exhaust gas upstream of the first DeNOx system (5), - Detecting a second content (S20) of the component of the exhaust gas downstream of the first DeNOx system (5), - comparing (S30) the first and the second detected (S10, S20) content of the component and - Controlling (S40) the internal combustion engine (3) so that an H2 content of the exhaust gas is adjusted based on the result of the comparison (S30). Control unit (1) Claim 1 or 2 , wherein the internal combustion engine (3) is designed as a direct injection hydrogen engine and wherein the control unit (1) is designed and set up to supply hydrogen to the internal combustion engine (3) during control (S40) of the internal combustion engine (3) in an exhaust stroke of the internal combustion engine (3), so that the H2 content of the exhaust gas is adjusted based on the detected content (S10) or based on the result of the comparison (S30). Control device (1) according to one of the preceding claims, wherein the control device (1) is designed and set up, when controlling (S40) the internal combustion engine (3), a fuel-air ratio, an ignition time, an injection time, an EGR rate and / or to control an inlet pressure. Control device (1) according to one of the preceding claims, wherein the control device (1) is designed and set up to take into account a knock limit, a combustion center of gravity, a load requirement and / or a NOx emission of the internal combustion engine (3) during control (S40). Control device (1) according to one of the preceding claims, wherein the exhaust gas aftertreatment system (4) comprises a metering unit (19), wherein the metering unit (19) is designed and set up to supply a reducing agent containing H2 or NH3 to the exhaust gas aftertreatment system (4) and wherein the control device (1) is designed and set up to cause the reducing agent to be supplied by the metering unit (19). Control device (1) according to one of the preceding claims, wherein the first DeNOx system (5) is designed as an H2-SCR system or as an NH3-SCR system. Control unit (1) after one of the Claims 1 to 6th , the exhaust gas aftertreatment system (4) comprising a second DeNOx system (6), the second DeNOx system (6) being arranged downstream of the first DeNOx system (5), the first DeNOx system (5) being designed as an H2-SCR system and wherein the second DeNOx system (6) is designed as an NH3-SCR system. Control unit (1) Claim 7 or 8th , wherein the NH3-SCR system comprises a three-way catalytic converter or a NOx storage catalytic converter. Control unit (1) Claim 8 or 9 combined with Claim 6 , wherein the control device (1) is designed and set up to detect a loading state of the NH3-SCR system (6) and to take into account the detected loading state when supplying reducing agent by the metering unit (19). Control unit according to one of the Claims 8 to 10 combined with Claim 6 , wherein the exhaust gas aftertreatment system (4) between the H2-SCR system (5) and the NH3-SCR system (6) is designed with a first (51) and a second (52) exhaust gas flow, wherein - the exhaust gas aftertreatment system (4) a Closing device (53) so that an exhaust gas flow flowing through the first (51) and second (52) exhaust gas flow can be controlled, - the first (51) and second (52) exhaust gas flow each include a NOx storage catalytic converter (8) and - the Dosing unit (19) is designed and set up to supply a reducing agent to the first (51) and / or second (52) exhaust gas flow. Control device according to one of the preceding claims, wherein the exhaust gas aftertreatment system (4) comprises a particle filter and / or an oxidation catalyst.

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