DE19736967A1 - Method and arrangement for monitoring NOx reservoir in combustion engine esp diesel engine exhaust gas output line - Google Patents

Abstract

Regenerating NOx reservoir in an exhaust line of a diesel or lean mixture engine, producing exhaust gas containing NOx, is monitored by measuring temperature to provide information on the operating capability, operating condition and/or storage capacity of the reservoir. Preferably, temperature is measured at a defined time by a direct measurement of least part of the reservoir or an indirect measurement via the gas flowing through it, before, during and/or after the regeneration phase. Also claimed is an arrangement for carrying out the method, with temperature sensor and electronics, together with a device comprising an oxidisable catalyst.

Description

The present invention relates to a method, an arrangement and a Device for monitoring a regenerable NOx storage in one Exhaust line through which a gas containing NOx flows. The invention is especially when monitoring exhaust gas from an internal combustion engine can be used, especially diesel and lean engines.

The increasing environmental awareness and the accompanying always Stricter exhaust gas legislation requires that it be harmful classified exhaust components are largely reduced. The one today Three-way catalytic converter common in motor vehicles is capable of carbon mon oxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx). Monitoring and control of the catalyst is carried out, for. B. by means of a Oxygen probe. This absorbs the residual oxygen content in the exhaust gas, from which the air-fuel ratio of the Gemi to be fed to the engine is set. By appropriate regulation of the residual oxygen Content is ensured that the catalyst has sufficient exhaust gases Implemented wisely. Furthermore, it is also known that the temperature profile on Determine catalyst and ver this as a warning or control variable turn. A further development of this procedure allows that at to determine the amount of heat released by the catalytic reaction and by means of  an oxygen sensor downstream of the catalytic converter via entropy consideration of the exhaust gas behavior of the engine. The three different ways just described, a three-way Monitoring catalyst is described in EP 0 298 240 B1.

In particular, during the cold start phase, an internal combustion engine falls seem to an increased pollutant emissions. To reduce this, be heated catalysts in the exhaust line of an internal combustion engine scheduled. The operation of such a catalytic converter goes out, for example WO 93/17228 or EP 0 628 134 B1 equivalent thereto. The use of adsorbers for storage during the start phase resulting unburned hydrocarbons and their release hot catalyst is also part of the prior art. Both is described for example in EP 0 485 179. Especially for them Zeolites and others have catalytic conversion of nitrogen oxides Materials proven to be suitable which also serve as hydrocarbon storage can be used. Suitable catalysts are described, for example, in EP 0 459 396 and EP 0 286 967.

The operability of a catalytic converter is therefore, as described above, monitored by its catalytic action during operation is checked. Various methods for this are described in WO 92/03643 or the equivalent EP 0 545 976 B1, WO 94/21902, WO 91/14855 or the equivalent EP 0 521 052 B1, WO 92/03642 or the equivalent EP 0 545 974 B1 and DE 26 43 739 described. The latter discloses, for example, how about a Temperaturver equal measurement with the help of two temperature sensors that ablau at the catalyst reaction is measured. The temperature difference determined in this way gives an indication of whether the catalytic converter is still functional or not.  

This type of temperature monitoring is not only for a main catalytic converter gate, but also applicable to a pre-catalyst.

A temperature sensor for monitoring is, for example, in part structured sheet metal layers built honeycomb bodies between them attachable. This is described in EP 0 603 221 B1.

The operation of catalysts depends on the operation of the Ver internal combustion engine. With stationary internal combustion engines in Germany TA-Luft is the regulation to be followed. Because the stick oxide limitation from the fuel heat output of the internal combustion engine and depending on the type of engine, the legislature carried out a so-called Dynamization clause for compression ignition engines on: According to the State of the art are motor and other measures for the mind exhaust emissions. Background of the dynamic clause was the insufficient maturity of denitrification plants in 1985. For Stationary combustion engines are used to denitrate urea used.

Use fails in internal combustion engines for motor vehicles of urea u. a. on the tank to be carried and its weight. Starting from the three stick that can be distinguished in terms of their formation substance oxides, namely fuel, prompt and thermal nitrogen oxide, other ways are sought, the formation of nitrogen oxides, especially thermi to keep nitrogen oxides low. It is known for commercial vehicles become exhaust gas recirculation with recooled exhaust gases. It is also known that water injection causes NOx emissions can be reduced. However, regarding this possibility, there is Problem of frost protection and carrying water as an operating resource. A another way to reduce nitrogen oxide emissions is to use them  caching. This is possible, for example, by means of a spoke chers containing barium or platinum.

The object of the present invention is now to create a method with which a NOx storage device at least checks its functionality can be. Furthermore, an arrangement is created that such Checking the NOx storage permits as well as a device that is special can be used in a space-saving manner in an exhaust line.

The present task regarding the method is done with a method with the features of claim 1, with respect to an arrangement with the Features of claim 17 and with respect to a device with the Features of claim 19 solved. Other advantageous features and Refinements are specified in the respective dependent claims.

A method according to the invention for monitoring a regenerable NOx storage in an exhaust line through which NOx-containing gas flows, provides for carrying out a temperature measurement on the exhaust system arm on the operability, the operating state and / or on the memory capacity of the NOx storage is closed. As exhaust line are all to understand those lines that produce a NOx Exhaust gas originating from a source, for example an internal combustion engine lead away. The operability states whether the NOx storage at all is still able to store nitrogen oxides. By monitoring the Operability is by specifying a limit or a band width regarding the measured temperature to one, the exhaust gas regulations appropriate operability of the NOx storage targeting check possible. The operating status gives at least for the time of Temperature measurement valid statement regarding an evaluation of the behavior the memory with respect to, for example, predetermined exhaust gas limit values,  Temperatures, aging or the like and is a qualitative statement. The Storage capacity of the NOx storage, on the other hand, is a quantitative statement which is absolute or related to a normal state.

A further development of the method provides for the temperature to be carried out measurement at a defined point in time, which is advantageous by a control or even regulation for the NOx storage or in Ver binding with further devices additionally arranged in the exhaust line controls can be carried out. The defined point in time is in execution tion of the method according to the mode of operation of the NOx storage adjustable. Is the memory downstream of an internal combustion engine and if this is driven approximately under constant load, the time will be the temperature measurement set so that with a known possible Amount of NOx memory of the memory is certainly not this limit is exceeded. When considering such a limit can, in addition to parameters such as structure, material and mode of operation of the NOx storage time-related factors such as aging. The monitor chung is carried out in an execution of the method by a continuous Temperature measurement, in another version by be spaced, individual temperature measurements. There are also two or more successive temperature measurements can be linked. At successive temperature measurements will be in a further development the distance between these shortens when the NOx Spei has a significant reduction in his skills. This is ensured that its no longer tolerable storage operation early is registered and appropriate measures can be taken.

The temperature measurement in the exhaust system is carried out either as a direct temperature temperature measurement of at least part of the NOx storage or as one indirect temperature measurement by means of the flowing through the NOx storage  Gas flow. The direct temperature measurement takes place in the material of the spoke chers itself. For this purpose, a temperature sensor is on the upper, for example surface, in an upper layer or directly in the material of the NOx storage arranged. The type of current sensor as well as the location of its location depends on how the NOx storage is constructed. The NOx spit cher can be made of ceramic, sintered or extruded, but also made of sheet metal, which are layered, for example, at least partially structured be. Also the sintering or extrusion of metal with ceramic powder turns out to be beneficial to the various properties of materia to be able to link them together. The NOx storage is a honeycomb can be designed monolithically. Other shapes are also possible. The NOx-storing material is in an advantageous embodiment Wall material distributed, especially so that the storage capacity is complete can be exploited. Another favorable embodiment sees one Coating, for example, of a NOx storage device constructed from sheet metal in front. If the material of the NOx storage has poor thermal conductivity on, the temperature sensor is close to that of NOx-containing Attach gas-flooded surface. When storing with good heat Conductivity, for example metal storage, is a temperature sensor can be used as described in EP 0 603 222 B1 already mentioned in the prior art is disclosed and its features to the content of this description belong. To do this, it must be ensured that the coating of a such body does not lead to falsifications of the temperature measurement.

The indirect temperature measurement by means of the NOx storage flowing gas stream is in a further embodiment of the Ver driving through a temperature sensor located in the gas flow guided. For this purpose, all known and suitable in the prior art Temperature sensors such as thermo elements or the like can be used. Of the Temperature sensor is arranged in one of the channels within the memory  net. In a further advantageous embodiment of the method, the Temperature sensor in the gas flow behind the NOx storage, in particular before a possibly three-way catalytic converter. On this arrangement The easiest term is the term indirect temp explain temperature measurement. It is namely from the gas flow to the NOx storage closed.

The temperature measurement takes place before, during and / or after a regeneration phase of the NOx storage. At these defined points in time, the following combinations have proven to be particularly advantageous:

• - A temperature measurement during, before or after the regeneration phase: Via a measurement at a specific point in time or also A statement about the NOx storage is possible over a period of time,
• - a temperature measurement immediately before the regeneration phase and during this: From the temperature difference can on the NOx-Spei be closed back,
• - During and after the regeneration phase: This also leaves examples point from the temperature difference to the memory and especially towards the quality of regeneration,
• - immediately before and immediately after the regeneration phase: the The temperature difference between the two measurements also gives a statement Regarding the quality of the regeneration, whereby again on the NOx memory can be closed; for a statement in the In the future it has proven to be advantageous, at least two tempera to link the door measurements after the regeneration phase. The temperature shift that occurs in relation to the time Chen distance between the two measurements leaves a temporal statement regarding the behavior of the NOx storage,  
• - Combinations of the above temperature measurements: These result in a particularly precise information regarding the behavior of the NOx storage chers.

The temperature is measured so that it can be used to draw a conclusion about the temperature Operability, the operating state and / or on the storage capacity of the Allows NOx storage. This is to be understood to mean that with such a Proceed without further conversion steps from the measured temperature based on the memory.

It is for a particularly significant statement of the temperature measurement advantageous if the regeneration phase within seconds, especially re completed within a second or less. The Regenera tion, which causes an exothermic reaction, is by a tempera increase in door detectable. This change in temperature and its type of Change is on the one hand on the storage material itself, on the other hand on the detectable gas flowing through the storage. The shorter the regeneration phase to release the stored nitrogen oxides, the clearer falls the temperature rise out. The aim is therefore particularly sudden temperature arising over the entire cross section of the NOx accumulator rise. This is then inside or downstream of the storage acceptable. This rise in temperature can be further increased by that oxidation is also triggered in the NOx storage. This can are triggered due to the exothermic reaction or by others Means, for example by a catalytic coating or equivalent de Adding a gas to the NOx-containing gas stream, which is the storage flows through.

The regeneration phase itself is carried out in an execution of the process by adding a regenerating agent to the NOx-hal  caused gas flow, the agent is able to save the stored loosened nitrogen oxides. In particular, the agent is able to the nitrogen oxides themselves to participate in a reaction. In a continuation This process is followed by the addition of the one which triggers regeneration By means of the source generating the NOx itself. Especially in this case Method, it is advantageous if the reactions taking place in the memory be carried out catalytically. For this purpose, the NOx storage device, for example in addition to the storage material also a catalytic coating.

For temperature measurement as well as for its evaluation, it is important that it itself and / or the regeneration is controlled. In a rain Otherwise, the ration phase, which runs within tenths of a second, occurs temporal inaccuracies that falsify the measurement result or results would make a statement regarding the behavior of the NOx trap the temperature is not possible. When using a common Electronics for the control of regeneration and temperature measurement there is the further advantage that the selection for a defined time point of measurement or regeneration in connection can become dependent, for example, on overriding considerations like the operation of an internal combustion engine.

For a statement about the operability, the operating condition and / or the storage capacity of the NOx storage, it is also advantageous to the tempe rature measurement so that the observation of the temporal Behavior of the temperature is possible. Catalysts are different most temperature measurement techniques and evaluation methods related to the Activity of the catalyst and its behavior for the future, for example to be able to determine. In particular for a method in which the tempera tur in connection with a regeneration phase of the NOx storage such measurement methods can also be used. Here  is, however, in contrast to a catalyst in a NOx storage a phase in which the NOx storage does not work in storage operation, concluded on its ability to store. From the stand already writings mentioned in the art are various temperature evaluations drive, measuring points and sensors known, which also with corresponding Adaptation to the NOx storage are applicable. It is about the writings in particular around WO 94/21902, EP 0 521 052 B1, EP 0 545 974 B1, EP 0 603 222 B1, EP 0 545 976 and DE 26 43 739, their corresponding features on the content of this description exercise belong.

In another method according to the invention, the back conclusion on the operability, the operating state and / or the memory capacity of the NOx storage a functional relationship between the Temperature, a characteristic of the NOx storage and / or a gas Part of the NOx-containing gas used. This can be based on experience about the long-term behavior of the NOx storage as well as relationships, resulting from the processing of various materials for the NOx storage result, be used. Regarding one or more gas inventory In part, their entropies or enthalpies are suitable for closing the NOx store monitor. This can be done, for example, by modifying EP 0 298 240 B1 known method for monitoring the pollutant content of exhaust gases in internal combustion engines possible, which also with its corresponding features belong to the content of this description.

Another advantageous method for monitoring the NOx store provides for the following steps:

• - The NOx stored in the NOx storage depending on the NOx-hal current gas flow is calculated,  
• - If a predefinable limit value for the NOx is exceeded, a Regeneration is triggered
• - Taking from the temperature measured by comparison with a predeterminable temperature value and / or a predeterminable temperature the conclusion about the operability, the operating condition and / or on the storage capacity of the NOx storage.

In a control or regulation, for example, via a Electronics controlling NOx source is carried out in a training of Procedure determined how large the volume flow and the NOx content in the Is gas flow that flows through the storage. The volume flow is over Known measuring methods can be determined, the NOx content, for example, at Internal combustion engine from the calculation of the air-fuel mixture, which of these is fed. Other data are also required for the calculation the internal combustion engine can be used, such as its operating and / or status Data. These can also be recorded in at least one map and such can be saved so that it can use an engine management system. Is comparable also with suitable data in other areas of application of the invention applicable. To avoid nitrogen oxide unsaved the memory flow through, the limit is set so that it can be excluded. This limit value does not have to be fixed constantly. Rather, he is with for example due to aging of the NOx storage over a long period Operating period can also be adapted to the functionality of the same.

The predeterminable temperature value and / or the predeterminable temperature band widths are based on empirical values for the NOx storage used can be crystallized out and stored in suitable electronics. This Empirical values can also take the form of a functional connection be given, with various parameters such as aging, tempera structure, mode of operation and other factors.  

If the process is developed further, a defined its temperature triggered a signal, the signal of a rating the operability, the operating state and / or the storage capacity of the NOx storage depends. In conjunction with available ones Data about a memory and predefinable evaluation criteria is the off evaluation with respect to the measured temperature so that the user any information like the still available storage capacity that is true apparent lifespan or the like is available. That from one defined, d. H. Predeterminable temperature triggered signal is in particular also a warning signal that indicates a malfunction in good time. Farther the signal triggered in this way can be used in such a way that a change in the Ab gas flow is effected. For example, the NOx storage is in a state that only has an extremely low storage capacity or if there is damage to the memory, preferably the operation changed the NOx source. For example, this is then in an emergency pro gram switchable.

A particularly preferred area of application of a method according to the invention is an internal combustion engine, in particular a diesel or lean engine, which preferably works under load changes. Such a method can be used above all in motor vehicles. A further development provides that a HC-enriched and oxygen-rich gas stream is introduced into a NOx storage catalyst as NOx storage for regeneration, the gas stream preferably being enriched with HC to the extent that the entire stored and convertible NOx is converted. This is generally done first by forming H ₂ O and CO from the HC and the oxygen, the CO then reacting with the NOx to form CO ₂ and N ₂ . Another development uses a rich enrichment of the combustion mixture in the engine to generate sufficient hydrocarbons and CO. The formation of H ₂ O and CO from hydrocarbons and oxygen in front of the NOx accumulator in the engine regenerates the NOx accumulator again. Hydrocarbons and / or CO have proven to be suitable for regeneration.

The storage catalytic converter preferably has a coating of Mixture of oxidation and storage materials as well as a catalytic active material. But he can also completely from a Mi research of these materials. Depending on how big the anrei is hydrocarbon in the gas stream, the temperature drops increased during the regeneration phase of the NOx storage. About the reaction of nitrogen oxide with hydrocarbon to nitrogen, water and coal di oxide is released as completely as possible. As special it has been found to be advantageous to react within approximately one Second or less.

In one example of a lean engine, one liter corresponds to a storage volume about 2 g of stored nitrogen oxide. This roughly corresponds to a drive travel between one and two miles, depending on the mode of operation Vehicle. Then the NOx storage must be regenerated again. Wuh The NOx storage catalytic converter has a heat capacity of around 600 J / l / K has an exothermic energy of about 14 to 20 kJ per 2 g NOx free. With a 100% conversion of the stored nitrogen oxides is a Temperature rise of 23 K due to the CO reaction and a tempera increase due to the HC reaction of 48 K was found.

The hydrocarbon enrichment is advantageously carried out so that the completely stored nitrogen oxide is implemented. Provided A sufficient HC content in the exhaust gas is the temperature increase proportional to the amount of nitrogen oxide stored. The HC addition is still so controllable that the storage by adding in smaller doses  is gradually regenerated. When using appropriate measuring sensors ren is again a statement about the ability of sections of the Memory possible. Is the added hydrocarbon for regeneration larger than necessary, the nitrogen oxides are fully implemented before exposed that they are also completely detachable from memory. They don't converted hydrocarbons are advantageously in a succession three-way catalyst implemented. By using an electroni engine management for temperature measurement, regeneration and the conclusion on the operability, the operating state and / or on the storage capacity is always accessible to the nitrogen oxide causal source, the internal combustion engine. Regenerating can for example, a misfire is caused, causing unburned Hydrocarbons get to the NOx storage.

Further advantageous refinements and features of the invention are described in shown in the following drawing. Show it:

Fig. 1 is an internal combustion engine with a downstream NOx storage catalyst and three-way catalyst,

Fig. 2 shows a time course of a regeneration phase of a NOx SpeI Chers,

Fig. 3 different behaviors of different NOx stores over time and

Fig. 4 shows an arrangement of a NOx source with an upstream oxidation catalyst.

Fig. 1 shows an arrangement 1 for monitoring a regenerable NOx memory 2 . The arrangement 1 has, at least in addition to the regenerable NOx store 2, means for regenerating the NOx store 2 , in this case the upstream internal combustion engine 3 , a temperature sensor 4 in the NOx store or in the exhaust gas stream 5 for monitoring the store 2 and an electronic component 6 , which has a connection 7 to the Temperatursen sensor 4 . The electronic component 6 is preferably a motor controller. This motor control is programmable, inputs being made via an input unit 8 . A three-way catalytic converter 9 is connected downstream of the NOx store 2 . Is to be regenerated, the NOx storage 2, since the elec tronic component 6 from which the internal combustion engine 3 inflowing fuel 10 and air flow 11 has in connection with the operation of a threshold value for the nitrogen oxide storage capacity of the NOx store calculation net, the internal combustion engine 3 is so controlled that this has a squib and thereby the exhaust gas stream 5 is enriched with unburned hydrocarbons. Other measures, such as a corresponding fuel injection into the exhaust gas stream 5 , can also be carried out. If the added and unburned hydrocarbon content is higher than required for the regeneration, the excess is converted in the catalyst 9 . The arrangement 1 furthermore has a first lambda probe 12 . 1 in front of the NOx accumulator 2 , a second lambda probe 12.2 between the accumulator 2 and the catalytic converter 9 and a third lambda probe 12.3 behind the catalytic converter 9 . They are used to check the hydrocarbon content of the exhaust gas stream 5 and can also be used to control or regulate the internal combustion engine 3 . Instead of the lambda probes 12.1 , 12.2 and 12.3 , however, temperature sensors can also be attached. The three-way catalytic converter 9 itself also has a temperature sensor 4 for monitoring. The dashed connecting line from this temperature sensor 4 to the electronic component 6 indicates the optionality of this monitoring. In another arrangement, the NOx accumulator 2 has two or more temperature sensors 4 , which is indicated by dashed lines. According to the arrangement 1 shown , a device can thus be configured for monitoring the regenerable NOx store 2 in the exhaust line 13 , through which the NOx-containing gas 5 flows, the store 2 being a catalyst. The catalyst has an oxidation ability that affects at least carbon monoxide and hydrocarbon. In the case of such a device, it has proven to be advantageous for the temperature measurement if the temperature sensor is arranged approximately behind a quarter of the length of the catalytic converter, viewed from an upstream side. This is preferably arranged about half the length of the catalyst.

Fig. 2 shows a possible behavior of the temperature in a NOx storage catalyst over time. When a nitrogen oxide limit is reached at time 71, the exhaust gas stream is enriched with unburned hydrocarbons until time 72 . An exothermic reaction then takes place in the NOx storage catalytic converter, which has the effect of an increase in temperature. This can be measured and evaluated, which is indicated by the slope Δδ / Δτ and the integration.

Fig. 3 shows various curves of the storage of nitrogen oxides in a NOx trap. The course a1 follows a monotonically increasing hyperbolic function, a2 corresponds to a monotonically decreasing hyperbolic function, the course b linear and the course c corresponding to a root function. In addition to these profiles, sinusoidal functions or others are also possible. Since the storage of nitrogen oxides triggers an endothermic reaction, this means a decrease in the temperature of the storage. If the course of the storage is now known for a memory, a temperature can be created from this as a comparison value for a temperature measurement. In connection with the measurement of a temperature immediately before, during or immediately after the regeneration, this basis then allows a statement about the NOx storage. To achieve this basis, it is possible, for example, to obtain a base temperature via the electrical resistance of the memory or based on experience.

FIG. 4 shows a second arrangement 14 with an oxidation catalytic converter 15 in the flow direction in front of the NOx store 2 , which is arranged closer to the NOx source 3 than to the NOx store 2 . When directly connected to the NOx source 2, the exhaust gas stream 5 quickly heats up the oxidation catalytic converter 15 . For the regeneration, it has proven to be expedient for improved absorption and formation of a characteristic temperature profile on the NOx store 2 if the exhaust gas for regeneration has a lower oxygen content than in normal operation. This is possible for example by enriching a combustion mixture of an internal combustion engine. An oxygen storage capacity of the NOx storage 2 is advantageously less than that of the following three-way catalytic converter 9 , preferably only about a third, in particular less than a tenth or even less. The exhaust gas stream 5 can then be as rich as it is, in any case it is converted, while the NOx store 2 in turn does not heat up too much due to an exothermic reaction. The oxidation catalyst 15 therefore also has a greater oxygen storage capacity than the NOx storage 2 but a smaller oxygen storage capacity than the three-way catalyst 9 . The NOx storage 2 has in particular at most a negligible ability to store oxygen or no ability to do so.

The present invention manages to safely monitor the Nitrogen oxide emissions from NOx sources through use and verification of a storage facility and thereby future emission limits  for example with diesel or lean engines for motor vehicles can.  

Reference list

1

arrangement

2nd

NOx storage

3rd

Internal combustion engine

4th

Temperature sensor

5

Exhaust gas flow

6

electronic component

7

connection

8th

Input unit

9

Three-way catalyst

10th

Fuel flow

11

Airflow

12.1

,

12.2

.,

12.3

Lambda probe

13

Exhaust line

14

second arrangement

15

Oxidation catalyst

Claims (25)

1. Procedure; For monitoring a regenerable NOx storage device ( 2 ) in an exhaust line ( 13 ) through which a NOx-containing gas ( 5 ) flows, in which a temperature measurement is carried out in the exhaust line ( 13 ), from which the operability, the operating state and / or the storage capacity of the NOx store ( 2 ) is concluded. 2. The method according to claim 1, characterized in that the tempera door measurement is carried out at a defined point in time. 3. The method according to claim 1 or 2, characterized in that

• - A direct temperature measurement of at least part of the NOx storage ( 2 ) or
• - An indirect temperature measurement by means of the gas flow flowing through the NOx store ( 2 )
• - Before, during and / or after a regeneration phase of the NOx storage ( 2 ) is carried out.

4. The method according to any one of the preceding claims, characterized in that the temperature is measured so that it directly allows a conclusion on the operability, the operating state and / or on the storage capacity of the NOx memory ( 2 ). 5. The method according to any one of claims 1 to 3, characterized in that in order to draw conclusions about the operability, the operating state and / or the storage capacity of the NOx storage ( 2 ), a functional relationship between the temperature, a characteristic of the NOx storage ( 2 ) and / or a gas component of the NOx-containing gas ( 5 ) is used. 6. The method according to any one of claims 3 to 5, wherein the regeneration phase within seconds, especially within one second or less is completed. 7. The method according to any one of the preceding claims, characterized records that the temporal behavior of the temperature is observed. 8. The method according to any one of claims 3 to 7, characterized in that the regeneration phase by adding a the regeneration triggering agent in the NOx-containing gas stream. 9. The method according to any one of the preceding claims, characterized in that a reaction in the NOx store ( 2 ) is carried out catalytically. 10. The method according to any one of the preceding claims, wherein the Ver drive for an internal combustion engine ( 3 ), in particular a diesel or lean engine for monitoring a combustion engine downstream NOx memory ( 2 ) is used. 11. The method for an internal combustion engine according to claim 10, characterized in that in a NOx storage catalyst as NOx-Spei cher ( 2 ) for regeneration a hydrocarbon and / or CO-enriched gas stream is introduced, preferably by a rich combustion mixture, the gas stream preferably as far as enriched with hydrocarbons and / or CO that the entire stored and convertible NOx is implemented. 12. The method for an internal combustion engine according to claim 10 or 11, characterized in that by forming H ₂ O and CO from hydrocarbons and oxygen in front of the NOx storage, in particular in the engine; subsequently the NOx storage is regenerated, the CO reacting further with the NOx to form N ₂ and CO ₂ . 13. A method for an internal combustion engine according to one of the claims che 10 to 12, characterized in that the temperature measurement, the Regeneration and the conclusion on the operability, the loading operating state and / or on the storage capacity via an electronic Engine management is done. 14. The method according to any one of the preceding claims, characterized in that

• the NOx stored in the NOx store ( 2 ) is calculated as a function of the NOx-containing gas stream ( 5 ), in particular in the case of the internal combustion engine, from its operating data and / or its operating state,
• - If a predefinable limit value for the NOx is exceeded, a regeneration is triggered,
• - Wherein from the temperature measured by comparison with a predeterminable temperature value and / or a predeterminable temperature range, the conclusion regarding the operability, the operating state and / or the storage capacity of the NOx-Spei chers ( 2 ).

15. The method according to any one of the preceding claims, characterized in that a signal is triggered from a defined, measured temperature, the signal from a rating of the operability, the operating state and / or the storage capacity of the NOx storage ( 2 ) depends. 16. The method according to any one of the preceding claims, characterized in that a signal is triggered from a defined measured temperature, which causes a change in the NOx-containing gas stream ( 5 ). 17. Arrangement for monitoring a regenerable NOx store ( 2 ), the at least

• - a regenerable NOx store ( 2 ),
• - Means for regeneration of the NOx storage ( 2 ),
• - A temperature sensor ( 4 ) for NOx storage monitoring in the NOx storage ( 2 ) or in the exhaust gas stream ( 5 ) and
• - An electronic component ( 6 ), which has a connection to the temperature sensor ( 4 ).

18. The arrangement according to claim 17, which at least further

• - A three-way catalyst ( 9 ), seen in a direction of flow through the NOx accumulator ( 2 ), lies behind it,
• - a lambda probe ( 12.1 ) for checking the hydrocarbon C content in front of the NOx store ( 2 ),
• - a lambda probe ( 12.2 ) for checking the hydrocarbon C content after the NOx store ( 2 ),
• - A NOx source ( 3 ), in particular an internal combustion engine, in the flow direction in front of the NOx accumulator ( 2 ) and / or
• - A management for controlling and / or regulating at least one of the components mentioned in claim 17.

19. The arrangement ( 1 ) according to claim 17 or 18 with an oxidation catalyst ( 15 ) in the flow direction in front of the NOx accumulator ( 2 ), which is preferably arranged closer to the NOx source ( 3 ) than to the NOx accumulator ( 2 ) , in particular directly adjoins the NOx source ( 3 ). 20. Arrangement according to one of claims 17, 18 or 19, characterized in that an oxygen storage capacity of the NOx storage ( 2 ) is less than that of the subsequent three-way catalyst ( 9 ), preferably about a third, in particular about one Tenths or less. 21. Arrangement according to one of the preceding claims 17 to 20, characterized in that the oxidation catalyst ( 15 ) has a greater oxygen storage capacity than the NOx storage ( 2 ) but a smaller oxygen storage capacity than the three-way catalyst ( 9 ). 22. Arrangement according to one of claims 17 to 21, characterized in that the NOx storage ( 2 ) has at most a negligible ability to store oxygen. 23. Device for monitoring a regenerable NOx store ( 2 ) in an exhaust line ( 13 ) through which a NOx-containing gas ( 5 ) flows, the regenerable NOx store ( 2 ) being a catalyst which has an oxidizing ability and has a storage capacity for NOx, with a temperature sensor ( 4 ) for carrying out a method according to claims 1 to 17. 24. The device according to claim 23, characterized in that the oxides ability at least the oxidation of carbon monoxide and carbon affects hydrogen. 25. Device according to one of the preceding claims, characterized in that the temperature sensor ( 4 ) behind about a quarter of a length of the catalyst, viewed from an upstream side, is arranged in the catalyst, preferably about half the length of the catalyst.