DE102009060286A1 - Vehicle, particularly motor vehicle, has exhaust system, which has catalyst system operating according to principle of selective catalytic reduction with selective catalytic reduction-catalyst arranged in exhaust channel of exhaust system - Google Patents

Abstract

The vehicle has an exhaust system (14), which has a catalyst system (20) with a selective catalytic reduction-catalyst (22) and has an ammonia storage system (24). The ammonia storage system has a storage, which is formed as a replacement cartridge (26) replaceable by a user of the vehicle. The ammonia-storage material of the replacement cartridge is selected from ammonia-complexed metal salts, particularly alkali, alkaline earth and transition metal salts, and ammonia adsorbing solids, particularly activated carbon and zeolite.

Description

The invention relates to a vehicle with an exhaust system, which has a catalyst system operating on the principle of selective catalytic reduction (SCR).

Internal combustion engines that are operated intermittently or predominantly with a lean air-fuel mixture produce nitrogen oxides NO _x (mainly NO ₂ and NO), which require NO _x -reducing measures. A motor measure for reducing the NO _x raw emission in the exhaust gas is the exhaust gas recirculation, in which part of the exhaust gas of the internal combustion engine is recirculated into the combustion air, whereby the combustion temperatures are lowered and thus the NO _x formation is reduced. However, the exhaust gas recirculation is not always sufficient to comply with legal NO _x limits, so in addition an active exhaust aftertreatment is required, which reduces the NO _x -Edemission. A known NO _x exhaust aftertreatment provides for the use of NO _x storage catalysts that store nitrogen oxides in the form of nitrates during lean operation (at λ> 1) and desorb the stored nitrogen oxides at short intervals with a rich exhaust gas atmosphere (λ <1) and reduce to nitrogen N ₂ in the presence of the reducing agent present in the rich exhaust gas.

As another approach to the conversion of nitrogen oxides in exhaust gases mlauflauffähiger internal combustion engines, the use of catalyst systems is known which operate on the principle of selective catalytic reduction (SCR for selective catalytic reduction). These systems comprise at least one SCR catalyst which, in the presence of a reducing agent continuously fed to the exhaust gas, usually ammonia NH ₃ , converts the nitrogen oxides of the exhaust gas into nitrogen and water. In this case, the ammonia can be added from an aqueous ammonia solution to the exhaust gas stream or be obtained from a precursor compound, for example urea, by way of thermolysis and hydrolysis. A promising new approach to ammonia storage in vehicles is NH ₃ storage materials, which reversibly bind ammonia as a function of temperature. In particular, metal-ammonium stores are known in this connection, for example MgCl ₂ , CaCl ₂ and SrCl ₂ , which store ammonia in the form of a complex compound, in order then to contain, for example, MgCl ₂ (NH ₃ ) _x , CaCl ₂ (NH ₃ ) _x or SrCl ₂ (NH ₃ ) _{x to be} present. From these compounds, by supplying heat, the ammonia can be released again. The advantage of metal-ammonium storage is that these compounds can store at atmospheric pressure a large amount of ammonia in very small volumes. For example, one mole of SrCl ₂ binds eight moles of NH ₃ . In addition, these compounds allow a good controllable release of ammonia and are very safe.

In order to achieve a faster start-up readiness, it is known to provide, in addition to one or two main memories, a comparatively small-volume sized start memory, which usually has an electrical heating device. The main memory can be heated either with an electric heater or with a supplied with engine cooling water heater. In the warm-up phase, the startup tank, which is heated and ready for use due to its low volume, takes over the NH ₃ supply of the SCR catalytic converter. Its heating takes place until the operating pressure is built up in the main memory. Only when the thermally inert main memory has built up its operating temperature and operating pressure, the entire NH ₃ supply is taken from this. The starting memory is then loaded with NH ₃ from the main memory and thus has at virtually every system start a virtually identical NH ₃ level.

DE 10 2006 061 370 A1 describes a similar system in which the main memory has a NH ₃ storage material with relatively high NH ₃ vapor pressure, in particular SrCl ₂ (NH ₃ ) _x , and a small-volume operating memory is provided, which is a NH ₃ storage material with relatively lower NH ₃ Contains vapor pressure, in particular MgCl ₂ (NH ₃ ) _x . Due to the different vapor pressures, the mass transfer from the SrCl ₂ storage to the MgCl ₂ storage is supported, so that the filling of the latter is accelerated. The NH ₃ supply of the SCR catalyst takes place in this system exclusively from the operating memory, which in turn is loaded by the main memory.

All known ammonia storage systems of the prior art are designed so that when exhausted the NH ₃ storage material in one of the memory this must be replaced by qualified personnel. The storage facilities are installed in such a way that their replacement must take place during an inspection in the workshop. This is relatively inflexible for a driver. This concept also leads to a shortening of the service intervals or to an accumulation of the required inspections.

The invention is based on the object to propose a motor vehicle with an SCR catalyst system, in which the ammonia supply of the ammonia storage system is made possible substantially independent of workshop visits or inspections.

This object is achieved by a vehicle having the features of claim 1.

The vehicle according to the invention has an exhaust gas system which has a catalytic system operating on the principle of selective catalytic reduction (SCR), which comprises at least one SCR catalytic converter arranged in an exhaust gas channel of the exhaust gas system and an ammonia storage system. The ammonia storage system contains at least one storage that contains an NH ₃ storage material that is capable of releasing ammonia NH ₃ depending on the temperature. According to the invention, it is provided that at least one of the accumulators of the ammonia storage system is designed as an interchangeable cartridge exchangeable by a user of the vehicle, which is arranged on a position of the vehicle accessible to the user without construction measures. The term "accessible without construction measures" means a position in or on the vehicle which is readily accessible to the vehicle user, in particular does not require the use of a tool. If necessary, the vehicle user must open a flap and / or use a vehicle key to get to the removable cartridge. The exchangeable replaceable cartridge, which can be accessed, ensures that replacement of this ammonia storage tank is possible without a visit to the workshop and can be changed independently of a service interval. Thus, a simple exchange by the user when needed is possible.

According to an advantageous embodiment of the method, the at least one interchangeable cartridge is housed in an engine compartment of the vehicle below a hood. Thus, the vehicle user only has to open the hood, to what he is used by other measures, such as the refilling of mop water, engine oil or cooling water. Alternatively, the at least one interchangeable cartridge can be arranged to be accessible within a trunk of the vehicle. Thus, according to this embodiment, only the opening of the tailgate is required to get to the interchangeable cartridge. In a further alternative arrangement, the interchangeable cartridge is located below an outer body of the vehicle, in particular under an outer panel, from where it can be arranged accessible below a flap, which may be configured similar to a fuel filler flap.

According to a further advantageous embodiment, the at least one removable cartridge is interchangeable without tools, that is, the vehicle user can perform by hand without the use of tools necessary for replacement handles, in particular remove a deflated cartridge and insert a new one. Alternatively, the vehicle may be equipped with an on-board tool, with the help of the removable cartridge can be replaced. In any case, it is thus ensured that a layperson without technical training is capable of exchange.

In an advantageous embodiment of the invention, the at least one interchangeable cartridge on a quick coupling, which is designed so that the interchangeable cartridge with a vehicle-mounted cartridge holder, which serves to accommodate the interchangeable cartridge, is connected in a gastight manner. For example, the quick coupling can be operated as a locking connection, screw or a tensioning lever mechanism. Such, well-known types of connection can be operated intuitively and safely by the laity without much effort.

In a further advantageous embodiment of the invention, the ammonia storage system has at least one vehicle-mounted cartridge holder for receiving the interchangeable cartridge, which may have an integrated heating device and optionally at least one temperature measuring point and / or a pressure measuring point. By the peripheral connections heating device, temperature and pressure measuring points are provided integrated on the vehicle side, makes it possible to make the removable cartridge robust and inexpensive. In particular, the interchangeable cartridge comprises only one, for example made of a plastic or metal sheet vessel for receiving the NH ₃ storage material and a suitable connection mechanism, in particular the quick coupling for connection to the cartridge holder.

It may further be provided that the at least one interchangeable cartridge has a safety closure which is designed to automatically close the interchangeable cartridge when not installed. In this way, it is impossible that when disassembling the removable cartridge ammonia can escape into the environment. Also, it can not happen in this way that the vehicle user forgets to close the cartridge after its removal.

According to a further advantageous embodiment, the interchangeable cartridge is equipped with an insertion aid to support a tilt-free and correct use and / or it has a shape that supports the tilt-free and correct use. By way of example, the cartridge may have a conically tapered shape in the direction of a connection point to the cartridge holder. Also, the design can be designed such that the interchangeable cartridge can be used only in a specific orientation. These measures increase system security by preventing improper cartridge deployment and potentially leaking connections.

In addition, it can be provided with particular advantage that the ammonia storage system comprises at least two exchangeable cartridges. In this way, the NH ₃ supply of the system can first be operated from one of the exchangeable cartridges and, when depleted, be converted to a second cartridge without interruption. This makes it possible to use up the replaceable cartridge completely and not have to hold NH ₃ reserve buffer. Thus, the system can operate virtually uninterrupted and the vehicle user to carry out the exchange at a convenient time for him.

According to a particularly advantageous embodiment, the ammonia storage system comprises, in addition to the at least one interchangeable cartridge, at least one operating store which contains an NH ₃ storage material which reversibly binds ammonia in a temperature-dependent manner. In this case, the system is set up so that an NH ₃ supply of the SCR catalytic converter takes place from the at least one operating store and this is loaded continuously or discontinuously by the interchangeable cartridge.

In addition, it can be provided that, alternatively or in addition to the at least one operating memory, a comparatively large-volume main memory is provided, which likewise contains an NH ₃ storage material, which reversibly binds ammonia in a temperature-dependent manner. In this case, the system is set up such that an NH ₃ charge of the operating memory takes place from the at least one main storage, which in turn is loaded from the at least one interchangeable cartridge. In this way it is possible that the relatively large-volume main memory, a relatively large amount of NH ₃ is kept in the ammonia storage system, which can be reloaded from one or more removable cartridges, if the capacity of the main memory is insufficient to the NH ₃ need a service interval cover up.

In connection with a plurality of exchangeable cartridges, a control device of the SCR catalyst system can be present, which is configured to supply the NH ₃ supply of the SCR catalytic converter or its NH ₃ charge initially in the presence of at least one operating store and / or at least one main store control the first interchangeable cartridge and, if the NH ₃ level of the first interchangeable cartridge is below a lower limit or equal to zero, the NH ₃ supply of the SCR catalyst or the NH ₃ loading of the operating and / or main memory on a second removable cartridge convert. This ensures uninterrupted operation. In this regard, the controller may be further configured to output a cartridge replacement signal to a driver and / or to an onboard diagnostic (OBD) system when the NH ₃ supply or load from the first interchangeable cartridge is terminated and converted to the second interchangeable cartridge has been. In this case, the signal can be supplemented with an indication of an anticipated driving distance, which can be covered with the second interchangeable cartridge. Preferably, the cartridge replacement signal is output only when the removable cartridge to be replaced falls below a lower temperature threshold and / or a lower pressure threshold, so that their replacement is safely possible. In this way, the vehicle user does not have to be expected to wait until a sufficient cooling of the interchangeable cartridge is done.

According to a further advantageous embodiment of the invention, the NH ₃ storage material of the at least one replaceable cartridge is selected such that it has a higher NH ₃ vapor pressure than the NH ₃ storage material of the at least one operating store and / or the at least one main store. In this way loading of the operating or main storage due to the difference of the NH ₃ vapor pressures is facilitated. In this context, it is possible to dispense with a heating device of the at least one replaceable cartridge, since the NH ₃ reuse proceeds spontaneously.

In an alternative embodiment, however, the NH ₃ storage material of the at least one interchangeable cartridge can also be selected with a particularly low NH ₃ vapor pressure, as a result of which the interchangeable cartridge must satisfy lower stability requirements. In particular, the interchangeable cartridge, if it is transported for example in the trunk as a reserve and is also exposed to heating due to sunlight, can withstand only lower pressures.

The NH ₃ storage material of the at least one interchangeable cartridge is preferably selected from the group of NH ₃ -complexing metal salts, in particular from the alkali metal and alkaline earth metal salts and transition metal salts. In particular, MgCl ₂ (NH ₃ ) _x , CaCl ₂ (NH ₃ ) _x and SrCl ₂ (NH ₃ ) _x should be mentioned here. However, it is also possible to use NH ₃ -adsorbing solids, in particular acid-activated activated carbon and zeolites, ammonia or ammonia solutions. If a material with a relatively low NH ₃ vapor pressure is to be used for safety reasons, in particular MgCl ₂ (NH ₃ ) _{x is} to be preferred.

Further advantageous embodiments are the subject of the remaining dependent claims.

The invention will be explained in more detail in embodiments with reference to the accompanying drawings. Show it:

1 a motor vehicle according to the invention;

2 an exhaust system of a motor vehicle in a first embodiment of the invention;

3 an exhaust system of a motor vehicle in a second embodiment of the invention;

4 an exhaust system of a motor vehicle in a third embodiment of the invention;

5 an exhaust system of a motor vehicle in a fourth embodiment of the invention;

6 an exhaust system of a motor vehicle in a fifth embodiment of the invention; and

7 an exhaust system of a motor vehicle in a sixth embodiment of the invention.

1 shows a total of 10 designated motor vehicle having an inventive SCR catalyst system, of which various preferred embodiments in the 2 to 7 are shown schematically.

2 shows an internal combustion engine 12 with a connected exhaust system 14 , In the internal combustion engine 12 it is an at least temporarily or permanently lean running engine, such as a diesel engine.

An exhaust gas of the internal combustion engine 12 gets into an exhaust duct 16 the exhaust system 14 initiated, where at a near-engine position, a first catalyst 18 may be arranged, for example, an oxidation or 3-way catalyst.

The exhaust system 14 further comprises an SCR catalyst system operating on the selective catalytic reduction principle 20 that is an SCR catalyst 22 , in particular a NO _x -reduction catalyst, and a total with 24 has designated ammonia storage system. The ammonia storage system 24 comprises at least one NH ₃ memory for receiving a NH ₃ storage material, wherein of the intended storage according to the invention at least one as an exchangeable removable cartridge 26 is trained. In the in 2 Example shown are all NH ₃ storage as removable cartridges 26 designed. The removable cartridges 26 each comprise an unillustrated NH ₃ storage material which is capable of releasing ammonia NH _{3 as a} function of the temperature. The exchangeable cartridges are via a coupling system, in a cartridge holder 28 used, from which they preferably without the use of a tool, but at most with one as an accessory in the vehicle 10 existing on-board tool, can be removed and used in this.

To the removable cartridges 26 or to bring the contained therein NH ₃ storage material to its required operating pressure is for each cartridge 26 one heating device each 30 intended. This can be an electrical heating device or a heating device operated with a liquid medium, which is heated, for example, by an engine cooling water or a thermal oil. The heater 30 can be done on the removable removable cartridge 26 be provided or - preferably - in the vehicle-mounted, permanently installed cartridge holder 28 be integrated; both alternative arrangement possibilities are in 2 shown. In addition, in the illustrated embodiment, the cartridge holder 28 a temperature sensor 32 on, in the alternative, but less preferred version also on the part of the removable cartridges 26 can be arranged. Alternatively or in addition to the temperature sensor 32 may be a pressure measuring point (not shown) on the cartridge side or by the cartridge holder 28 be provided. The integrated arrangement of the heater 30 and the temperature measuring point and / or pressure measuring point in the cartridge holder 28 has the advantage that the replaceable removable cartridge 26 can be easily and inexpensively designed. Furthermore, the risk of damaging sensitive elements of the interchangeable cartridge 26 minimized. Also, the connection of the removable cartridge 26 with the cartridge holder 28 be simplified because no electrical contacts or fluid connections must be made.

In the case of the cartridges 26 The NH ₃ storage material present is preferably an NH ₃ -complexing metal salt, which is also referred to as metal ammine. For example, the compounds MgCl ₂ (NH ₃ ) _x , CaCl ₂ (NH ₃ ) _x and SrCl ₂ (NH ₃ ) _x are suitable here, which release the bound NH ₃ partly in stages. For example, the strontium chloride ammine complex, which can store up to 8 moles of NH ₃ per mole of SrCl _2, releases seven moles of NH ₃ upon reaching a temperature of about 60-80 ° C and the eighth mole of NH ₃ at about 150 ° C. In a preferred embodiment, an NH ₃ storage material is selected which has a relatively low NH ₃ vapor pressure. In particular, here MgCl ₂ (NH ₃ ) _{6 can be used} with advantage, which liberates ammonia to a significant extent only at temperatures above 140 ° C and thus generates an overpressure. This embodiment has the advantage that the safety of the vehicle 10 entrained, not yet used reserve cartridges 26 is increased, for example, if a passive heating is done by sunlight, or that the removable cartridges 26 can be designed with a lower pressure stability. Also in case of damage to the removable cartridge 26 , ammonia would be released only when the desorption temperature is reached.

The removable cartridges 26 are designed so that they can be easily replaced by a vehicle user without technical training - and not only by specialist personnel during a workshop visit - without any construction measures. For this it is advantageous that they are at a readily accessible position of the vehicle 10 are arranged. Possible arrangements are in 1 indicated. A first option is at least one of the removable cartridges 26 in a motor room 34 (in 1 indicated by a broken arrow) below a hood 36 of the vehicle 10 arranged. In this way, the vehicle user can change the cartridge / n 26 by simply opening the bonnet 36 reach and exchange. Alternatively, at least one of the removable cartridges 26 inside a trunk 38 (in 1 again indicated by a broken arrow) and by opening a tailgate 40 be accessible. Finally, at least one of the removable cartridges 26 in the area of an exterior body 42 of the vehicle 42 , in particular below a flap 44 , be positioned in an accessible way. This may be the flap 44 a conventional tank flap, which is next to the removable cartridge 26 also a tank neck covered, or your own, only the removable cartridge 26 covering flap.

To the safety and practicability of the inventive concept of removable cartridges 26 To further improve, they preferably have an automatic safety lock, which after removal of the removable cartridge 26 from the cartridge holder 28 the cartouche 26 automatically closes. Thus, on the one hand leakage of possibly remaining in the cartridge remaining ammonia is prevented and on the other hand, an unintentional opening of the cartridge before its insertion into the holder 28 , For example, a flap or panel may be the cartridge 26 in the uninstalled state and by a mechanism on the part of the cartridge holder 28 when inserting the cartridge 26 be pressed into the holder and opened. When removing the cartridge 26 from the holder, however, can provide a cartridge-side spring mechanism or the like for the automatic closing of the flap or aperture. Such safety closures are known in a variety of constructions from a wide variety of applications and require no further detail.

In addition, the at least one removable cartridge 26 have a quick coupling, with the help of the interchangeable cartridge 26 with the vehicle-mounted cartridge holder 28 or a gas line system of the ammonia storage system 24 is gas-tight connectable. Such quick couplings are known in the art from various applications. Also known and can be used with advantage within the scope of the invention are connection systems which combine the properties of a quick coupling and a safety closure. Preferably, the insertion of the interchangeable cartridge 26 in the cartridge holder 28 without the use of tools possible. At most, an on-board tool on the vehicle 10 be provided as an accessory, with the help of the insertion is to accomplish. Additionally, the correct fit of the cartridge 26 and / or the locking of the clutch are detected, for example, by sensors and commissioning of the vehicle 10 only permitted with positive detection of seat and locking.

Furthermore, the at least one removable cartridge 26 a size, a shape and a weight that allow easy handling by an average user. In addition, it should also be ensured that the removable cartridge 26 simple, safe and preferably only in a correct position in the cartridge holder 28 can be used. To ensure this, the at least one removable cartridge 26 have an insertion aid. For example, it may have a tapered conically in the direction of the coupling, whereby tilting of the cartridge 26 in the holder 28 is prevented. In addition, it may have an asymmetrical shape, which is insertion of the cartridge 26 only allowed in the correct orientation.

According to 2 stand the removable cartridges 26 each with a gas supply line 46 in conjunction, upstream of the SCR catalyst 22 in the exhaust duct 16 empties. It is at a suitable point of the line 46 a controllable metering device 48 arranged for variable adjustment of the NH ₃ stream, which may be configured as a throttle valve (mass flow regulator) or gas metering valve. The fluid connection between the removable cartridges 26 and the gas supply line 46 can via valves 50 be prepared or interrupted. Optionally, further temperature and / or pressure measuring points can be arranged in the line system (not shown). in 2 is with 45 a coupling or quick coupling indicated which the cartridge holder 28 with the line 46 combines. As stated above In contrast, it is preferably provided, such a coupling for producing a connection between the removable cartridge 26 and cartridge holder 28 additionally or alternatively provided.

The signals of the temperature sensors 32 and optionally pressure sensors are input to a controller 52 for controlling the operation of the ammonia storage system 24 , The control device 52 controls in response to these and other signals, the heating power of the heaters 30 , the position of the valves 50 as well as the position of the metering device 48 , The latter takes place in particular depending on an ammonia requirement of the SCR catalyst 22 which is detected either via an NO _x sensor (not shown) installed in the exhaust duct or in dependence on an operating point of the engine 12 , in particular from an engine speed, an engine load, an engine temperature, etc., can be determined by calculation or by means of NO _x maps. The control device 52 may be installed as a standalone device or integrated into an engine control unit (not shown).

The control device 52 is preferably set up so that the ammonia supply of the SCR catalyst 22 initially from a first of the existing removable cartridges 26 he follows. Once an NH ₃ level of the first removable cartridge 26 a lower limit or equal to zero, the valves are 50 controlled so that the NH ₃ supply to a second removable cartridge 26 is converted. If this is done, the controller gives 52 a cartridge replacement signal, which is displayed to the driver and which can additionally be stored in an OBD system. Preferably, the cartridge replacement signal is not output to the driver until the replacement cartridge to be replaced 26 a lower temperature threshold and / or a lower pressure threshold below, which are selected so that a safe removal is possible. This prevents the vehicle user, after he has been asked to change the cartridge, first cooling the cartridge 26 has to wait.

3 shows a modification of the ammonia storage system 24 out 2 , The same elements are provided with the same reference numerals and will not be explained again in detail. In addition, attention was paid to the presentation of the control device 52 omitted in this and the following figures for reasons of clarity. This in 3 shown system differs from that of the 2 in that in addition to the two removable cartridges 26 another NH ₃ memory is provided, in particular an operating memory 54 , The operating memory 54 can one, compared with the removable cartridges 26 , relatively small volume and is surrounded by a built-in system and only interchangeable by qualified personnel insulating jacket. Just like the removable cartridges 26 is also the operating memory 54 with an electric or fluid powered heater 56 equipped and with a valve 58 with the gas supply line 46 connected. Unlike in the 2 As shown in the execution of the system 3 the ammonia supply of the SCR catalyst 22 not directly from the removable cartridges 26 but from the operating memory 54 , which is heated continuously for this purpose at its operating temperature or at its operating pressure. On the other side is the in 3 not shown control device 52 set up the NH ₃ charge of the storage 54 initially from a first removable cartridge 26 to control and, if the NH ₃ level of the first interchangeable cartridge 26 a lower limit or zero, the NH ₃ loading of the memory 54 on a second removable cartridge 26 convert. In this case, the NH ₃ loading of the operating memory 54 during operation of the SCR catalyst system 20 or after the system has been shut down. Also in this embodiment, the output of the cartridge replacement signal is performed by the controller 52 preferably after cooling the replaceable cartridge 26 below a suitable temperature or pressure threshold.

The operating memory 54 contains an NH ₃ storage material that is able to reversibly bind NH _{3 in a} temperature-dependent manner. Preferably, this is selected from one of the abovementioned metallammine compounds. In the in 3 shown embodiment, the NH ₃ storage material of the operating memory 54 on the one hand and the removable cartridges on the other 26 on the other hand be chosen so that the NH ₃ storage material of the removable cartridges 26 has a higher NH ₃ vapor pressure than that of the operating memory 54 , This configuration makes it possible to the heaters 30 the removable cartridges 26 to renounce, as a result of the vapor pressure difference, a spontaneous reloading of the memory 54 he follows.

4 shows a further alternative embodiment of the ammonia storage system 24 , This includes a removable cartridge 26 and a working memory 54 one compared to the operating memory 54 or the interchangeable cartridge 26 relatively large-volume main memory 60 , The main memory 60 contains an NH ₃ storage material that reversibly binds or releases ammonia depending on the temperature. This may be from the in connection with the storage material of the interchangeable cartridge 26 be selected materials mentioned. Again, the NH ₃ storage material of the interchangeable cartridge 26 with a higher vapor pressure than the main memory 60 chosen be so on the heater 30 the interchangeable cartridge 26 can be waived. At the in 4 The system shown, the ammonia supply of the SCR catalyst 22 exclusively from the continuously heated operating storage 54 , The operating memory 54 is during operation of the SCR catalyst system 20 or after being turned off by the main memory 60 loaded for this purpose via a heating device 62 Has ammonia from the NH ₃ storage material of the main memory 60 release. The main memory 60 turn over the removable cartridge 26 loaded continuously or discontinuously with NH ₃ . If this is exhausted or their NH ₃ level falls below a predetermined lower limit, their fluid connection by closing the valve 50 interrupted and ended their heating. After cooling the replaceable cartridge 26 gives the controller 52 turn a cartridge replacement signal to the vehicle user.

5 shows a variant of in 4 shown ammonia storage system 24 , which differs from this in that two or more removable cartridges 26 are provided to the main memory 60 wiederzubeladen. In particular, here the system is set up so that the removable cartridges 26 alternately to the loading of the main memory 60 be operated, so if one of the removable cartridges 26 is emptied, the NH ₃ loading of the main memory 60 on another removable cartridge 26 is converted. After cooling the emptied exchangeable cartridge 26 This can be changed at any time without interruption of the system.

The ammonia storage system 24 , this in 6 is shown, also includes an interchangeable cartridge 26 , an operating memory 54 and a large-volume main memory 60 , This system is designed so that in turn the ammonia supply of the SCR catalyst 22 through the continuously heated operating memory 54 he follows. The NH ₃ charge of the operating memory 54 is done by the main memory 60 that has a valve or check valve 64 with the gas supply line 46 is connectable. In this embodiment, the volume or the capacity of the main memory 60 so that its NH ₃ storage is designed for the length of an average service interval. However, in modern vehicles, variable inspection intervals are sought, which are dependent, for example, on oil aging and customer use behavior. In the event that the capacity of the main memory 60 due to an above-average service interval or deviating customer use behavior is not sufficient until the next inspection date, the vehicle user is promptly depleted of the main memory 60 prompted the system by inserting an interchangeable cartridge 26 to expand. After emptying the main memory 60 Then there is a switchover of the NH ₃ loading of the operating memory 54 from the main memory 60 on the removable cartridge 26 , Alternatively, here also a direct operation on the removable cartridge 26 This is done by adding the NH ₃ supply to the SCR catalyst 22 takes over. In the in 6 system shown is a cartridge change by the vehicle user therefore only required if that in the main memory 60 entrained NH ₃ amount is not sufficient for the service interval.

In the 7 illustrated embodiment differs from the embodiment according to 6 in that two or more removable cartridges 26 can be provided. The removable cartridges 26 can be operated so that the working memory 54 from these is filled or the removable cartridges 26 be used as operating cartridges by directly make the NH ₃ dosage in the exhaust gas. Here, the removable cartridges 26 be operated alternately, so that an unused (not heated) cartridge can be replaced.

The above-described embodiments allow an increase in customer convenience, since longer time intervals can be defined, within which a refill or a change of the main memory 60 can be done in the workshop. If the main memory is exhausted before the expiration of a service interval, the customer can change the replacement interval of the main cartridge 60 by using an exchangeable cartridge 26 extend. Because the interchangeable cartridge 26 can not be heated in normal operation in most embodiments, it can be ensured that the cartridge is not hot when changing cartridges and therefore is not under pressure in the clutch. This simplifies the security measures to be taken and reduces the potential danger to the user.

If the removable cartridge 26 with another memory (operating memory 54 and / or main memory 60 ), which is firmly installed in the vehicle (possibly replaced by service personnel), the ammonia from the removable cartridge 26 in the permanently installed memory 54 respectively 60 be relocated. This is the easy accessibility of the vehicle 10 firmly connected memory 54 . 60 not mandatory. The possibilities of its placement in the vehicle 10 are therefore very variable and it can be positioned in a location that is particularly protected in terms of a possible accident. The one with the vehicle 10 hard-wired storage 54 . 60 furthermore, it does not have to be standardized. It can be adapted in shape and size to the vehicle concept and therefore optimally use the space. In contrast, the removable cartridges 26 be available nationwide, for example at petrol stations. To ensure this is the use of a standardized type of removable cartridges 26 desirable because the provision of various designs for different vehicles and manufacturers is complex.

If more than one removable cartridge 26 can be used by each one of them. If a cartouche 26 is empty, the controller turns off 52 automatically to another removable cartridge 26 around. Only then the user is asked to change the exhausted cartridge. This has the advantage that by the control device 52 On the one hand, it can be ensured that the system can work without interruption. On the other hand, it can thus be ensured that the cartridge to be replaced 26 is cold and depressurized when the user is asked to change. This system also allows only exhausted cartridges to be replaced, for example as part of an inspection or workshop visit. In this way, the NH ₃ supply is used in the best possible way, with the simultaneous possibility of the memory 54 . 60 also to fill up between the service intervals, for example in preparation for a longer independent operation. In case of using multiple removable cartridges 26 can also work on a permanently installed main memory 60 be waived. As a result, smaller, rugged and / or non-contiguous space in the vehicle better used.

Overall, all the embodiments presented above, in which according to the invention the conventionally provided, permanently installed ammonia storage units are replaced or supplemented by interchangeable exchangeable cartridges lead to an increase in user comfort and to a flexibilization of inspection intervals.

LIST OF REFERENCE NUMBERS

10

vehicle

12

internal combustion engine

14

exhaust system

16

exhaust duct

18

first catalyst

20

SCR-catalyst system

22

SCR catalyst

24

Ammonia storage system

26

replaceable cartridge

28

cartridge holder

30

heater

32

Temperature measuring point / temperature sensor

34

engine compartment

36

Engine Hood

38

trunk

40

tailgate

42

vehicle body

44

flap

45

Coupling / quick coupling

46

Gas supply line

48

metering

50

Valve

52

control device

54

operating memory

56

heater

58

Valve

60

main memory

62

heater

64

Valve

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102006061370 A1 [0005]

Claims (15)

Vehicle ( 10 ) with an exhaust system ( 14 ), which uses a selective catalytic reduction (SCR) catalyst system ( 20 ) with at least one in an exhaust passage ( 16 ) of the exhaust system ( 14 ) arranged SCR catalyst ( 22 ) and with an ammonia storage system ( 24 ), wherein the ammonia storage system ( 24 ) at least one memory ( 26 . 54 . 60 ), which contains an NH ₃ storage material which is capable of releasing ammonia (NH ₃ ) as a function of temperature, characterized in that at least one of the storages ( 26 . 54 . 60 ) as one, by a user of the vehicle ( 10 ) interchangeable cartridge ( 26 ), which is located on a position of the vehicle accessible to the user without construction measures ( 10 ) is arranged. Vehicle ( 10 ) according to claim 1, characterized in that the at least one removable cartridge ( 26 ) in an engine compartment ( 34 ) of the vehicle ( 10 ) below a hood ( 36 ), inside a trunk ( 38 ), and / or below an exterior body ( 42 ), in particular below a flap ( 44 ), is arranged accessible. Vehicle ( 10 ) according to claim 1 or 2, characterized in that the at least one interchangeable cartridge ( 26 ) tool-free or by means of an on-board tool of the motor vehicle ( 10 ) is interchangeable. Vehicle ( 10 ) according to one of the preceding claims, characterized in that the at least one interchangeable cartridge ( 26 ) has a quick coupling, which is designed, the removable cartridge ( 26 ) with a vehicle-mounted cartridge holder ( 28 ) for receiving the replaceable cartridge ( 26 ) gas-tight. Vehicle ( 10 ) according to one of the preceding claims, characterized in that the ammonia storage system ( 24 ) at least one vehicle-mounted cartridge holder ( 28 ) for receiving the replaceable cartridge ( 26 ) having an integrated heating device ( 30 ) and optionally at least one temperature and / or pressure measuring point ( 32 ) having. Vehicle ( 10 ) according to one of the preceding claims, characterized in that the at least one interchangeable cartridge ( 26 ) has a safety closure which is configured, the removable cartridge ( 26 ) to close automatically when not installed. Vehicle ( 10 ) according to one of the preceding claims, characterized in that the at least one interchangeable cartridge ( 26 ) identifies an insertion aid for supporting a tilt-free and correct use and / or a shape supporting the tilt-free and correct use. Vehicle ( 10 ) according to one of the preceding claims, characterized in that the ammonia storage system at least two removable cartridges ( 26 ). Vehicle ( 10 ) according to one of the preceding claims, characterized in that the ammonia storage system ( 24 ) at least one operating memory ( 54 ) which contains an NH ₃ storage material which is capable of reversibly binding ammonia (NH ₃ ) as a function of temperature, and the system is set up such that an NH ₃ supply of the SCR catalyst ( 22 ) from the at least one operating memory ( 54 ) he follows. Vehicle ( 10 ) according to claim 9, characterized in that the ammonia storage system ( 24 ) in addition to the at least one operating memory ( 54 ) at least one relative to the operating memory ( 54 ) large-volume main memory ( 60 ) which contains an NH ₃ storage material which is capable of reversibly binding ammonia (NH ₃ ) as a function of temperature, and the system is set up such that an NH ₃ charge of the at least one operating store ( 56 ) from the at least one main memory ( 60 ) and an NH ₃ charge of the at least one main memory ( 60 ) from the at least one removable cartridge ( 26 ). Vehicle ( 10 ) according to one of claims 8 to 10, characterized in that the SCR catalyst system ( 20 ) a control device ( 52 ) which is arranged to supply the NH ₃ supply of the SCR catalyst ( 22 ) or the NH ₃ charge of the at least one operating memory ( 54 ) or the at least one main memory ( 60 ) first from a first removable cartridge ( 26 ) and, if an NH ₃ level of the first interchangeable cartridge ( 26 ) is below the lower limit or zero, the NH ₃ supply or the NH ₃ charge on a second interchangeable cartridge ( 26 ) change. Vehicle ( 10 ) according to claim 11, characterized in that the control device ( 52 ) is adapted to output a cartridge replacement signal if the NH ₃ supply or the NH ₃ charge from an interchangeable cartridge ( 26 ) and transferred to another removable cartridge ( 26 ) was converted. Vehicle ( 10 ) according to claim 12, characterized in that the control device ( 52 ) is set up to output the cartridge replacement signal only when the exchangeable cartridge ( 26 ) falls below a lower temperature threshold and / or a lower pressure threshold. Vehicle ( 10 ) according to claim 9 or 10, characterized in that the NH ₃ storage material of the at least one operating memory ( 54 ) and / or the at least one main memory ( 60 ) has a lower NH ₃ vapor pressure than the NH ₃ storage material of the at least one interchangeable cartridge ( 26 ). Vehicle ( 10 ) according to one of the preceding claims, characterized in that the NH ₃ storage material of the at least one interchangeable cartridge ( 26 ) from the group of NH ₃ -complexing metal salts, in particular the alkali, alkaline earth and transition metal salts; the NH ₃ -adsorbiernden solids, especially activated carbon and zeolites; Ammonia and its solutions is chosen.

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