DE102021107306A1 - Motor vehicle and method for operating such a motor vehicle - Google Patents

Abstract

The invention relates to a motor vehicle and a method for operating the motor vehicle. The motor vehicle has an internal combustion engine (1) and an exhaust gas aftertreatment system (2) for the aftertreatment of exhaust gas from the internal combustion engine (1) as well as a first pressure vessel (3) and at least one further pressure vessel (4), in each of which a fuel is used to drive the internal combustion engine ( 1) is stored under an increased storage pressure compared to normal conditions, a control system being provided which, when the internal combustion engine (1) is operating, controls a supply of the internal combustion engine (1) and the exhaust gas aftertreatment system (2) with the fuel in such a way that until it drops the storage pressure in the first pressure vessel (3) is at least predominantly supplied with fuel from the first pressure vessel (3) to a predeterminable first lower limit value of the internal combustion engine (1). After the storage pressure in the first pressure vessel (3) has dropped to or below the first lower limit value, the internal combustion engine (1) is supplied with fuel from the further pressure vessel (4) and the exhaust gas aftertreatment system (2) is at least temporarily supplied with fuel from the first pressure vessel (3 ) if the storage pressure in the first pressure vessel (3) is above a predeterminable second lower limit value, the second lower limit value being smaller than the first lower limit value.

Description

The invention relates to a motor vehicle with an internal combustion engine and an exhaust gas aftertreatment system with the features of the preamble of claim 1 and a method for operating such a motor vehicle with the features of the preamble of claim 6.

the DE 102017213523 A1 discloses a pressure container system for a motor vehicle with a first and a further pressure container in which a fuel used in the motor vehicle can be stored under an increased pressure. A pressure compensation device is provided to compensate for pressure differences in the pressure vessels. In this way, disruptive pressure differences can be compensated for, particularly when the pressure vessel is being refueled.

In contrast, the object of the invention is to provide a motor vehicle and a method for operating a motor vehicle with which an improved utilization of fuel stored in pressure vessels under increased pressure for driving the motor vehicle internal combustion engine can be achieved.

This object is achieved by a motor vehicle with the features of claim 1 and by a method with the features of claim 6.

The motor vehicle according to the invention has an exhaust gas aftertreatment system for aftertreatment of exhaust gas from the internal combustion engine as well as a first pressure vessel and at least one further pressure vessel, in each of which a fuel for driving the internal combustion engine is stored under an increased storage pressure compared to normal conditions. The motor vehicle according to the invention is characterized in particular by a control system which, when the internal combustion engine is operating, controls the supply of the internal combustion engine and the exhaust gas aftertreatment system with fuel in such a way that the internal combustion engine is at least predominantly fuel until the storage pressure in the first pressure vessel drops to a predeterminable first lower limit value is supplied from the first pressure vessel. After the storage pressure in the first pressure vessel has fallen to or below the first lower limit value, the internal combustion engine is supplied with fuel from the further pressure vessel and the exhaust gas aftertreatment system is at least temporarily supplied with fuel from the first pressure vessel if the storage pressure in the first pressure vessel is above a predeterminable second lower limit value is, wherein the second lower limit value is smaller than the first lower limit value.

The method according to the invention is characterized in that, in the motor vehicle, the internal combustion engine is at least predominantly supplied with fuel from the first pressure vessel until the storage pressure in the first pressure vessel drops to a predeterminable first lower limit value, and after the storage pressure in the first pressure vessel falls to or below the first lower limit value of the internal combustion engine is supplied with fuel from the further pressure vessel and the exhaust gas aftertreatment system is at least temporarily supplied with fuel from the first pressure vessel, provided that the storage pressure in the first pressure vessel is above a predeterminable second lower limit value, the second lower limit value being less than the first lower limit is.

The invention is based on the knowledge that in order to supply the internal combustion engine with fuel from one of the pressure vessels, a certain increased supply pressure is required which cannot be fallen below if proper operation of the internal combustion engine is to be guaranteed. If, starting from an initial full filling of the pressure vessel with a predetermined, increased nominal filling pressure, the storage pressure of the fuel in the first pressure vessel, from which the internal combustion engine is initially supplied, falls to or below this specific increased supply pressure, the internal combustion engine can therefore without pressure increasing means such as compressors , no longer be supplied with fuel from the first pressure vessel for its operation. According to the invention, however, the internal combustion engine can still be operated, since in this case, by means of the correspondingly designed control system, its supply of fuel is switched to the further, at least approximately fully filled pressure vessel. The switchover takes place when the storage pressure in the first storage tank has dropped to a predefined or predefinable first lower limit value, this limit value preferably depending on the design of the internal combustion engine or its operating requirements and being greater than 1 bar.

After switching the supply of the internal combustion engine to the further pressure vessel, there is a certain residual amount of fuel in the first pressure vessel, corresponding to the first lower limit value for the storage pressure, which can no longer be used for combustion in the internal combustion engine. Advantageously, in accordance with the concept of the invention, this residual amount of fuel in the first pressure vessel can nevertheless be used in a useful manner in the motor vehicle, at least for the most part, by using the exhaust gas aftertreatment system at least temporarily as required Fuel is supplied from the already more or less emptied first pressure vessel. Preferably, the exhaust gas aftertreatment system is already supplied with fuel from the first pressure vessel as required when its storage pressure is even higher than or equal to the first lower limit value. The fuel is preferably fed to a catalytic component arranged in the exhaust gas aftertreatment system, where it serves to support the exhaust gas purification due to its reducing effect. This makes use of the fact that a significantly lower pressure is typically required to introduce the fuel into the exhaust gas aftertreatment system than to supply the internal combustion engine. As a result, fuel can still be taken from the first tank and the utilization of its storage capacity is improved. The at least intermittent fuel supply to the exhaust gas aftertreatment system from the partially emptied first pressure vessel is advantageously maintained during operation of the internal combustion engine until the storage pressure there has fallen to or slightly below the predetermined or predeterminable second lower limit value. The second lower limit value depends essentially on requirements determined by the exhaust gas aftertreatment system. Typically, the second lower limit value is significantly lower than the first lower limit value.

If the storage pressure in the first pressure vessel has reached the second lower limit value, the control system switches the at least temporarily supplying the exhaust gas aftertreatment system with fuel to the further pressure vessel. It goes without saying that the described principle of the invention is not limited to the use of exactly two pressure vessels, but can be extended accordingly to three, four or more pressure vessels.

In an embodiment of the motor vehicle according to the invention, the fuel is hydrogen. This can be stored in gaseous form under high storage pressure in the pressure vessels. The nominal pressure of the accumulator is typically in the range between 300 bar and 700 bar. However, the hydrogen can also be stored in a cryogenic tank as a pressure vessel in predominantly liquid form. It is typically present there at a temperature of less than 33 K and a pressure of up to about 10 bar.

In a further embodiment of the invention, however, the fuel can also be a hydrocarbon, which is gaseous under normal conditions, or ammonia. Gaseous natural gas (as compressed natural gas = CNG) or liquefied natural gas (as liquefied natural gas = LNG) or a so-called liquefied petroleum gas (LPG) or biogas can be used as hydrocarbons. Depending on the hydrocarbon, the storage pressures are typically between about 5 bar and 200 bar or more, the storage temperatures between 113 K and the ambient temperature. Ammonia is preferably stored in predominantly liquid form at an increased pressure of up to about 9 bar and at ambient temperature in the pressure vessel.

Depending on the fuel used, which is gaseous under ambient conditions, the internal combustion engine is designed as a so-called gas engine, preferably as a hydrogen engine. An embodiment as a multi-cylinder reciprocating piston engine is generally preferred, it being possible for an external mixture formation to be provided with regard to the fuel-air mixture. In this case, an ignitable fuel-air mixture is formed outside a respective combustion chamber of the internal combustion engine and this is fed to the combustion chamber. However, in a further embodiment of the invention, an advantageous embodiment is an embodiment with internal mixture formation. In this case, the fuel is fed directly to a respective combustion chamber of the internal combustion engine, i.e. injected with a corresponding supply pressure.

In a further embodiment of the invention, the exhaust gas aftertreatment system has a nitrogen oxide reduction catalytic converter and the fuel can be fed to the exhaust gas aftertreatment system upstream of the nitrogen oxide reduction catalytic converter. The nitrogen oxide reduction catalytic converter can be a lean NOx catalytic converter, an SCR catalytic converter or a nitrogen oxide storage catalytic converter. The type of catalyst is preferably selected depending on the type of fuel used. In the case of hydrogen as the fuel, the use of a lean NOx catalyst or a nitrogen oxide storage catalyst is preferred. When using ammonia as fuel, the use of a classic SCR catalytic converter is advantageous. Fuel introduced into the exhaust gas is transported with the exhaust gas flow into the interior of the catalytic converter and reduces nitrogen oxides (NOx) contained in the exhaust gas or stored in the catalytic converter material to harmless nitrogen on its catalytically active surface. In addition, the use of a NOx trap comes into consideration, in which nitrogen oxides stored by the fuel supplied are mainly released.

In an embodiment of the method according to the invention, after the storage pressure in the first pressure vessel has dropped below the second lower limit value, the exhaust gas aftertreatment system is at least temporarily supplied with fuel from the further pressure vessel. As already mentioned, the second lower limit value is based on the requirements relating to the addition or injection of fuel into the exhaust gas aftertreatment system. For this However, only comparatively low pressures of typically less than 2 bar to 5 bar are required. In contrast, the supply pressures required to supply the internal combustion engine with fuel are significantly higher, for example 10 bar up to 50 bar. The first lower limit value and the remaining fuel quantity remaining in the pressure vessel when the first lower limit value is reached are correspondingly higher. By supplying the exhaust gas aftertreatment system with this residual amount of emerging fuel up to a maximum of the accumulator pressure dropping to the second lower limit value, the residual amount ultimately remaining at least in the first pressure vessel can be significantly reduced. This results in a significantly improved utilization of the fuel stored overall in the pressure vessels.

If there is a third pressure vessel in addition to the first and the further pressure vessel, after switching the fuel supply of the internal combustion engine from the first to the further pressure vessel, it is possible to switch over again - to the third pressure vessel - when the first lower limit value is reached in the further pressure vessel. Correspondingly, the exhaust gas aftertreatment system can be supplied with fuel from the first or the further pressure vessel until the second lower limit value for the accumulator pressure is reached in the further pressure vessel. The third pressure vessel is then available as a fuel source to support the exhaust gas cleaning.

In a further embodiment of the method, the fuel is fed to a component with an oxidation-catalytic effect arranged in the exhaust gas aftertreatment system and is at least partially oxidized in this component, releasing heat. In this way, heating of the exhaust gas flow or of the component which has an oxidation-catalytic effect is made possible. The same also applies to downstream components arranged in the exhaust gas aftertreatment system. With the introduction of heat into the exhaust gas, the corresponding components can be brought to operating temperature or kept at operating temperature more quickly. Accordingly, it is possible to shorten the warm-up time and expand the operating range of the exhaust gas aftertreatment system. The fuel combustion in the internal combustion engine is preferably set so that an oxygen-containing exhaust gas is emitted.

In this context, it is particularly advantageous if, in a further embodiment of the method, the fuel is fed to the exhaust gas aftertreatment system when a temperature in the exhaust gas aftertreatment system is below a predeterminable lower temperature limit value. A further temperature in the exhaust gas aftertreatment system is preferably monitored and the fuel is only fed to the exhaust gas aftertreatment system if the further temperature exceeds an upper temperature limit value. With the appropriate selection of the upper temperature limit value, it can be ensured that fuel supplied to the exhaust gas aftertreatment system can actually be oxidized in a corresponding component with an oxidation-catalytic effect, releasing heat.

• 1 eine schematische Systemskizze von Verbrennungsmotor, Abgasnachbehandlungssystem und Druckbehältern des erfindungsgemäßen Kraftfahrzeugs gemäß einer ersten vorteilhaften Ausführungsform, und
• 2 eine schematische Systemskizze von Verbrennungsmotor, Abgasnachbehandlungssystem und Druckbehältern des erfindungsgemäßen Kraftfahrzeugs gemäß einer zweiten vorteilhaften Ausführungsform.

The above and further features and advantages of the invention emerge from the following description of preferred, non-limiting exemplary embodiments of the invention with reference to the accompanying drawings. Show in it:

• 1 a schematic system sketch of the internal combustion engine, exhaust gas aftertreatment system and pressure vessels of the motor vehicle according to the invention according to a first advantageous embodiment, and
• 2 a schematic system sketch of the internal combustion engine, exhaust gas aftertreatment system and pressure vessels of the motor vehicle according to the invention according to a second advantageous embodiment.

This in 1 Exemplary system outlined only schematically comprises an internal combustion engine 1 , an exhaust aftertreatment system 2 and a first pressure vessel 3 and another pressure vessel 4th , in each of which a fuel is used to drive the internal combustion engine 1 is stored under an increased storage pressure compared to normal conditions. The fuel is a fuel that is gaseous under normal conditions, such as hydrogen, ammonia, methane or another hydrocarbon. The internal combustion engine is accordingly 1 designed as a gas engine. An embodiment as a multi-cylinder reciprocating piston engine is preferred. There can be an internal or external mixture formation of fuel with the internal combustion engine 1 supplied combustion air be provided. If a fuel stored in predominantly liquid form, such as ammonia or autogas, is used, an external mixture formation is preferred in which the fuel is outside of the combustion chambers of the internal combustion engine 1 is mixed with combustion air. If a fuel stored in gaseous form, such as hydrogen, natural gas (CNG) or biogas, is used, an internal mixture formation is preferred, in which the internal combustion engine 1 Fuel can be fed directly into the combustion chambers via injection valves. Combustion chambers and injection valves, as well as a corresponding air supply system, are preferably provided Pressure regulator for setting a relative to the storage pressure of fuel in the first pressure vessel 3 or in the second pressure vessel 4th reduced injection pressure not shown separately.

From the internal combustion engine 1 Exhaust gas generated and emitted during fuel combustion is fed to the exhaust aftertreatment system 2 supplied and released into the environment cleaned by this, which is indicated by the open arrows 5 , 6th is illustrated. The exhaust aftertreatment system 2 has a catalytic converter, not shown, which removes pollutants such as hydrocarbons (HC), carbon monoxide (CO) and NOx contained in the exhaust gas, in particular with the aid of in the pressure vessels 3 , 4th contained, effective as a reducing agent fuel can convert into harmless components. For this purpose, fuel is drawn from the first pressure vessel 3 upstream or on the input side via a first supply line 7th fed to the catalyst. Valves, pressure regulators and possibly further supply means which are expediently to be provided for this purpose are likewise not shown in greater detail for the sake of simplicity, as in the exhaust gas aftertreatment system 2 arranged sensors for temperatures and pollutant components such as NOx in particular.

A supply of fuel to drive the internal combustion engine 1 takes place via an to a switching valve 8th connected second supply line 9 . The switching valve, which is preferably designed as a three-way valve 8th is still via a first outlet line 10 to the first pressure vessel 3 and via a second outlet line 11 to the further, second pressure vessel 4th connected. A control unit 12th is via a control line 13th to the switching valve 8th connected and can use the switching valve 8th so control that fuel either from the first pressure vessel 3 or the further pressure vessel 4th via the first outlet line 10 or the second outlet line 11 and the second supply line 9 the internal combustion engine 1 is fed. Alternatively, continuously separate and separately controllable outlet lines from the first pressure vessel can also be used 3 and from the further pressure vessel 4th to the combustion engine 1 be led.

A selection of the pressure vessel from which the internal combustion engine 1 Fuel is supplied, takes place as a function of by pressure sensors 14th , 15th recorded accumulator pressures in the pressure vessels 3 , 4th , the corresponding pressure signals via signal lines 16 , 17th to the control unit 12th and are evaluated by it. The control unit 12th controls via the control line 13th the switching valve 8th so that the internal combustion engine 1 is supplied with fuel from the selected pressure vessel.

In the following, with further reference to 1 dealt with the operation of the motor vehicle or the system shown.

Starting from pressure vessels fully filled with a nominal pressure 3 , 4th is used to operate the internal combustion engine 1 this by appropriate actuation of the switching valve 8th Fuel from the first pressure vessel 3 fed. In this case, the fuel is preferably reduced from the nominal pressure or from the current storage pressure to an intended, in contrast, reduced supply pressure. The fuel is preferably burned in the internal combustion engine 1 predominantly or at least temporarily with excess air. Exhaust gas produced during fuel combustion is sent to the exhaust gas aftertreatment system 2 fed.

Through one in the exhaust aftertreatment system 2 arranged catalytic converter through which exhaust gas flows, pollutants contained in the exhaust gas are at least partially removed and the exhaust gas is thus cleaned. The exhaust gas aftertreatment system is used to carry out or support exhaust gas cleaning 2 or the catalyst, at least temporarily, fuel from the first pressure vessel 3 metered in. Here, too, there is preferably a pressure reduction of the fuel from the nominal pressure or from the current storage pressure in the first pressure vessel 3 to a specified metering pressure.

It is provided in particular that NOx contained in the exhaust gas during exhaust gas cleaning is reduced to nitrogen with the aid of the fuel that acts as a reducing agent. For this purpose, the catalytic converter is preferably designed as a nitrogen oxide reduction catalytic converter. This can be a selective NOx reduction catalytic converter such as a lean NOx catalytic converter, which can catalyze NOx even when there is an excess of oxygen by means of a selective NOx reduction. However, a NOx storage catalytic converter can also be provided which can store NOx under lean conditions. In this case, fuel is preferably supplied when regeneration of the NOx storage catalytic converter is provided, during which stored NOx is released and reduced. It can also be provided for heating or for maintaining an operating temperature of a component of the exhaust gas aftertreatment system 2 to feed this fuel in particular on the input side of a component which is effective in terms of oxidation catalysis. A demand-based supply of fuel to the exhaust gas aftertreatment system 2 is in any case expediently sensor-controlled by evaluating the signals from sensors for exhaust gas components and temperatures in the exhaust gas aftertreatment system 2 .

By removing fuel for combustion in the internal combustion engine 1 and / or to support exhaust gas cleaning in the exhaust gas aftertreatment system 2 the storage pressure in the first pressure vessel decreases 3 over time. Is it on or under one for the supply to the internal combustion engine 1 required minimum pressure has fallen, the internal combustion engine can 1 can no longer be operated properly with fuel drawn from the first pressure vessel. It is therefore provided that the storage pressure in the first pressure vessel 3 by evaluating the from the pressure sensor 14th provided signal by the control unit 12th is continuously monitored. It is found that a for proper operation of the internal combustion engine 1 the relevant first lower limit value is reached or undershot, the control unit is actuated 12th the switching valve 8th such that the internal combustion engine 1 Fuel from the further pressure vessel, which is at least approximately fully filled at this point in time 4th is fed. The need-based supply of fuel from the first pressure vessel 3 to the exhaust aftertreatment system 2 can remain unchanged because the first lower limit value for the accumulator pressure is typically significantly higher than the required metering pressure for introducing the fuel into the exhaust gas aftertreatment system 2 is. The required metering pressure is preferably a second lower limit value in the control unit 12th saved. Provided that the storage pressure in the first pressure vessel 3 the exhaust gas aftertreatment system does not fall below the second lower limit value 2 with fuel from the first pressure vessel 3 provided.

The sizes and thus the fuel storage capacities of the first pressure vessel are preferred 3 and the further pressure vessel 4th chosen so that when switching over the fuel supply of the internal combustion engine 1 from the first pressure vessel 3 on the further pressure vessel 4th in the first pressure vessel 3 The remaining fuel quantity enables at least as long a useful life for needs-based exhaust gas cleaning as the useful life, which is derived from the usable filling amount in the further pressure vessel 4th and the assumed fuel consumption of the internal combustion engine 1 results. In this case, as in 1 shown, it is not necessary to provide switching means with which the supply of the exhaust gas aftertreatment system 2 with fuel from the first pressure vessel 3 on the further pressure vessel 4th can be switched. However, this is also possible. In a corresponding embodiment, the exhaust gas aftertreatment system 2 until the storage pressure in the first pressure vessel drops 3 is supplied with fuel from this as required to the second lower limit value. Becomes the second lower limit value in the first pressure vessel 3 is then reached on the supply of the exhaust aftertreatment system 2 with fuel from the further pressure vessel 4th switched.

It should also be noted that the pressure vessel 3 , 4th also with respective separate outlet lines directly to the combustion engine 1 and the exhaust aftertreatment system 2 can be connected. Switching the supply to the internal combustion engine 1 and the exhaust aftertreatment system 2 from the first pressure vessel 3 on the further pressure vessel 4th can then be done by appropriately actuated valves in the outlet lines.

In general, it is in any case preferred if, for a given total fuel storage capacity of the first and further pressure vessels, the ratio of the individual fuel storage capacity of the first pressure vessel 3 to the individual fuel storage capacity of the additional pressure tank 4th is selected depending on the values of the first lower limit value and the second lower limit value for the accumulator pressure. The ratio of the pressure vessel sizes is thus preferably dependent on the first and second lower limit values for the storage pressure. First pressure vessel 3 and further pressure vessels 4th can thus have different sizes or individual fuel storage capacities. This enables a particularly high utilization of the total fuel storage capacity.

In 2 is one of the in 1 Similar system shown, with the corresponding components, as far as they are with the parts of 1 match, are identified by the same reference numerals. Due to the similarity to the in 1 The system shown below will only deal with differences in this regard.

This in 2 The system shown has in addition to the first and the further pressure vessel 3 , 4th yet another, third pressure vessel 20th for fuel stored under increased pressure. By means of control lines 27 , 28 , 29 to the control unit 12th connected switching valves 24 , 25th , 26th can fuel from a respective pressure vessel 3 , 4th , 20th the internal combustion engine 1 or the exhaust aftertreatment system 2 are fed. The pressure vessels are used for this 3 , 4th , 20th via respective outlet lines 21 , 22nd , 23 fluidly with one of the switching valves 24 , 25th , 26th tied together. The switching valves 24 , 25th , 26th the fuel obtained from a pressure vessel can be fed into a first collecting line 32 and a second manifold 33 hand over. The exhaust gas aftertreatment system is used here 2 via the to the first collecting line 32 connected first supply line 7th supplied with fuel. The internal combustion engine 1 is via the to the second collecting line 33 connected second supply line 9 supplied with fuel.

A selection of the pressure vessel from which the internal combustion engine 1 or the exhaust aftertreatment system 2 Fuel is supplied, takes place as a function of by pressure sensors 14th , 15th , 30th recorded accumulator pressures in the pressure vessels 3 , 4th , 20th , the corresponding pressure signals via signal lines 16 , 17th , 31 to the control unit 12th and are evaluated by it. The control unit 12th controls via the control lines 27 , 28 , 29 the switching valves 24 , 25th , 26th depending on the accumulator pressures recorded.

A preferred mode of operation of the in 2 system shown.

Starting from pressure vessels that are fully filled with a nominal pressure or at least filled with a storage pressure above the first lower limit value 3 , 4th , 20th become the internal combustion engine 1 and the exhaust aftertreatment system 2 as required by actuating the switching valve 24 with fuel from the first pressure vessel 3 provided. In this case, the fuel is preferably reduced from the nominal pressure or from the current storage pressure to an intended, in contrast reduced, respective supply pressure. The other pressure vessel 4th and the third pressure vessel 20th assigned switching valves 25th , 26th remain closed. Used by the control unit 12th a drop in the storage pressure in the first pressure vessel 3 is determined to be at or below the first lower limit value, the fuel supply to the internal combustion engine is then set 1 from the first pressure vessel 3 on the further pressure vessel 4th rearranged. The switching valves are used for this 24 , 25th operated accordingly. The third pressure vessel 20th assigned switching valve 26th remains closed.

Also falls in the further pressure vessel 4th If the accumulator pressure drops to or below the first lower limit value, then the fuel supply of the internal combustion engine is reduced 1 from the further pressure vessel 4th on the third pressure vessel 20th rearranged. The switching valves are used for this 25th , 26th operated accordingly.

The fuel supply of the exhaust gas aftertreatment system as required 2 from the first pressure vessel 3 remains maintained until the storage pressure in the first pressure vessel 3 falls to or below the second lower limit value. If this is determined by the control unit, then by appropriate actuation of the switching valves 24 , 25th the fuel supply to the exhaust aftertreatment system 2 from the first pressure vessel 3 on the further pressure vessel 4th switched.

Should also in the further pressure vessel during further operation of the motor vehicle 4th If the accumulator pressure drops to or below the second lower limit value, the fuel supply of the exhaust gas aftertreatment system will 2 by actuating the switching valves 25th , 26th from the further pressure vessel 4th on the third pressure vessel 20th rearranged.

The above-explained design of the motor vehicle according to the invention and the described mode of operation enable improved utilization of the existing fuel storage capacity and thus an increased range of the motor vehicle.

It should also be noted that for the in 2 illustrated embodiment with three pressure vessels the line routing for the fuel supply of the internal combustion engine 1 and the exhaust aftertreatment system 2 and the switching means provided for this purpose can be designed differently without departing from the scope of the invention. For example, internal combustion engine 1 and exhaust aftertreatment system 2 each directly with separate fuel lines with the pressure vessels 3 , 4th , 20th get connected. A line junction can also be used in the internal combustion engine 1 or be provided in the exhaust gas aftertreatment system.

List of reference symbols

1

Internal combustion engine

2

Exhaust aftertreatment system

3rd

First pressure vessel

4th

Another pressure vessel

5, 6

Open arrow

7th

First supply line

8th

Changeover valve

9

Second supply line

10

First outlet line

11

Second outlet line

12th

Control unit

13th

Control line

14, 15, 30

Pressure sensors

16, 17, 31

Signal lines

20th

Third pressure vessel

21, 22, 23

Outlet lines

24, 25, 26

Switching valves

27, 28, 29

Control lines

32

First collecting line

33

Second collecting line

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed 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 102017213523 A1 [0002]

Claims (10)

Motor vehicle with an internal combustion engine (1) and an exhaust gas aftertreatment system (2) for the aftertreatment of exhaust gas from the internal combustion engine (1) and with a first pressure vessel (3) and at least one further pressure vessel (4) in each of which a fuel is used to drive the internal combustion engine (1) is stored under an increased storage pressure compared to normal conditions, characterized in that a control system is provided which, when the internal combustion engine (1) is operating, controls a supply of the internal combustion engine (1) and the exhaust gas aftertreatment system (2) with the fuel in such a way that - to to lower the storage pressure in the first pressure vessel (3) to a predeterminable first lower limit value, the internal combustion engine (1) is at least predominantly supplied with fuel from the first pressure vessel (3), and - after the storage pressure in the first pressure vessel (3) has fallen to or below the first lower limit value of the internal combustion engine (1) with fuel au s is supplied to the further pressure vessel (4) and the exhaust gas aftertreatment system (2) is at least temporarily supplied with fuel from the first pressure vessel (3), provided that the storage pressure in the first pressure vessel (3) is above a predeterminable second lower limit value, the second lower limit value Limit value is smaller than the first lower limit value. Motor vehicle after Claim 1 , characterized in that the fuel is hydrogen. Motor vehicle after Claim 1 , characterized in that the fuel is a hydrocarbon or ammonia which is gaseous under normal conditions. Motor vehicle according to one of the Claims 1 until 3 , characterized in that the internal combustion engine (1) is designed as an internal combustion engine with internal mixture formation. Motor vehicle according to one of the Claims 1 until 4th , characterized in that the exhaust gas aftertreatment system (2) has a nitrogen oxide reduction catalytic converter and the fuel can be fed to the exhaust gas aftertreatment system (2) upstream of the nitrogen oxide reduction catalytic converter. A method for operating a motor vehicle with an internal combustion engine (1) and an exhaust gas aftertreatment system (2) for the aftertreatment of exhaust gas from the internal combustion engine (1) and with a first pressure vessel (3) and at least one further pressure vessel (4) in each of which a fuel is used to drive the Combustion engine (1) is stored under an increased storage pressure compared to normal conditions, characterized in that - until the storage pressure in the first pressure vessel (3) falls to a predeterminable first lower limit value, the internal combustion engine (1) at least predominantly with fuel from the first pressure vessel (3) is supplied, and - after the storage pressure in the first pressure vessel (3) has dropped to or below the first lower limit value, the internal combustion engine (1) is supplied with fuel from the further pressure vessel (4) and the exhaust gas aftertreatment system (2) at least temporarily Fuel is supplied from the first pressure vessel (3), so far the storage pressure in the first pressure vessel (3) is above a predeterminable second lower limit value, the second lower limit value being smaller than the first lower limit value. Procedure according to Claim 6 , characterized in that after the storage pressure in the first pressure vessel (3) has dropped below the second lower limit value, the exhaust gas aftertreatment system (2) is at least temporarily supplied with fuel from the further pressure vessel (4). Procedure according to Claim 6 or 7th , characterized in that nitrogen oxides contained in the exhaust gas are reduced by feeding the fuel to a nitrogen oxide reduction catalytic converter arranged in the exhaust gas aftertreatment system (2). Method according to one of the Claims 6 until 8th , characterized in that the fuel is fed to a component with an oxidation-catalytic effect arranged in the exhaust gas aftertreatment system (2) and is at least partially oxidized in this component, releasing heat. Procedure according to Claim 9 , characterized in that the fuel is fed to the exhaust gas aftertreatment system (2) when a temperature in the exhaust gas aftertreatment system (2) is below a predeterminable lower temperature limit value.

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