DE102015200125A1 - Catalytic converter for an internal combustion engine - Google Patents

Abstract

The invention relates to an exhaust gas catalytic converter (28; 30; 32) for an internal combustion engine (12), wherein the exhaust gas catalytic converter (28; 30; 32) is designed to catalytically change an exhaust gas of the internal combustion engine (12). According to the invention, the catalytic converter (28; 30; 32) has at least one first section (46) which can catalytically change the exhaust gas. In addition, the exhaust gas catalytic converter (28; 30; 32) has at least one second section (48) which is designed to store oxygen at least temporarily. Downstream of and adjacent to the second portion (48) is disposed at least one temperature sensor (38, 38a, 38b, 38c).

Description

State of the art

The invention relates to a catalytic converter according to the preamble of claim 1, as well as two methods and a control and / or regulating device according to the independent claims.

From the market, internal combustion engines are known, in particular diesel engines, which can oxidise or reduce hydrocarbons (HC) or nitrogen oxides (NOx) present in an associated exhaust system by means of a catalytic reduction in the exhaust gas.

Disclosure of the invention

The problem underlying the invention is achieved by an exhaust gas catalytic converter according to claim 1, and by two methods and a control and / or regulating device according to the independent claims. Advantageous developments are specified in subclaims. Features which are important for the invention can also be found in the following description and in the drawings, wherein the features, both alone and in different combinations, can be important for the invention, without being explicitly referred to again.

The invention relates to an exhaust gas catalytic converter for an internal combustion engine, wherein the exhaust gas catalytic converter is configured to catalytically change an exhaust gas of the internal combustion engine. According to the invention, the catalytic converter has at least one first section, which can catalytically change the exhaust gas. Furthermore, the catalytic converter has at least one second section, which is designed to store oxygen at least temporarily. Downstream of and adjacent to the second section is arranged at least one temperature sensor.

According to the invention, an oxygen storage capacity (also called "oxygen adsorption capacity") can be determined by means of the temperature sensor, which is arranged downstream of and adjacent to the second section. This is preferably done by means of a method in which a heat release during the storage of oxygen is determined and evaluated. Thereby, the catalytic effect of the first section can be monitored, as will be explained in more detail below. The catalytic converter designed according to the invention makes it possible in particular to carry out this method.

According to the invention, the at least one temperature sensor is arranged downstream of and in the flow path (fluidically) adjacent to the second section. "Adjacent" in the sense of the invention means that the temperature sensor is arranged at most far away from the second section such that the heat release described above can still be determined and evaluated when oxygen is stored by means of the at least one temperature sensor.

A catalytic converter within the meaning of the invention is any device in an exhaust system for the internal combustion engine, which is designed to catalytically change in the exhaust gas present hydrocarbons (HC), or nitrogen oxides (NOx), for example, to oxidize or reduce. In this case, the catalytic converter may in particular be an oxidation catalytic converter, a diesel oxidation catalytic converter (DOC), or a NOx storage catalyst (NSC). Likewise, a diesel particulate filter of the exhaust system may include a catalytic coating that has the ability to oxidize hydrocarbons.

In addition, the catalytic converter according to the invention can also be designed such that the first portion and the second portion are arranged away from each other. In particular, it is possible according to the invention for a section of the exhaust system to be arranged between the first and the second section, which section has neither a catalytic function nor an oxygen-storing effect. For example, the first and the second section are designed as separate modules, which are connected to one another only via a (possibly long) exhaust duct. This will be explained in more detail below.

An advantage of the exhaust gas catalytic converter according to the invention is that the second section used for monitoring the exhaust gas catalytic converter is essentially independent of the first section used for the actual function (ie the emission reduction in the exhaust gas) or can be operated independently thereof. The spatial separation of said functions undesired interactions can be prevented, which could damage a use of the catalytic converter according to the invention or a monitoring method according to the invention.

Another advantage is the comparatively low cost in terms of required sensors. In particular, temperature sensors, for example compared to lambda probes or HC sensors, are comparatively inexpensive and less susceptible to poisoning, sooting or other harmful influences.

Another advantage is made possible by the use of oxygen as a basis for the monitoring of the catalytic properties of the catalytic converter according to the invention. Oxygen is present throughout the exhaust system compared to many of today's measurable exhaust gas constituents (eg, hydrocarbon). Thus, the second portion of the catalytic converter according to the invention may be arranged, for example, at a downstream portion of the particulate filter. In this case, temperature sensors, which may already be present in the exhaust system for other purposes, are used for the invention.

Because the second section of the invention for the reasons described can be arranged at different locations in the exhaust system, this has the further advantage that such a location can be selected, which an optimal correlation between aging or deactivation of oxygen storage ability in the second section and results in a deterioration of the catalytic properties in the first section of the catalytic converter.

Preferably, the second portion may then be located upstream of the first portion of the catalytic converter to be monitored, if poisoning effects dominate in the catalytic converter, or if a thermal load in an upstream region of the catalytic converter is comparatively strong. However, if the aging of the (catalytically active) first portion of the catalytic converter is characterized essentially by an exothermic reaction of hydrocarbons or of soot particles present in the exhaust gas (which may result in a comparatively high temperature in a downstream region of the catalytic converter), then For example, the second section can preferably be arranged downstream of the first section of the catalytic converter to be monitored.

In one embodiment of the invention, the second section at least partially has an oxygen-storing coating, wherein the oxygen-storing coating comprises a cerium oxide material and / or a cerium / zirconium mixed oxide material and / or a praseodymium oxide material and / or a neodymium oxide material. These materials are particularly well suited for storing oxygen and for generating a sufficient thermal response that can be measured and evaluated using the at least one temperature sensor.

Furthermore, it can be provided that the second section additionally comprises a platinum material or a palladium material. This makes it possible for the second section-in addition to the oxygen storage capability according to the invention-to have at least partially a catalytic effect similar to the first section. Thereby, the ability of the exhaust gas catalyst to treat the exhaust gas can be improved.

Preferably, the second portion of the catalytic converter is formed and / or the second portion comprises such a material that an oxygen storage capacity of the second portion is correlated with a catalytic capability of the first portion. As a result, the catalytic properties of the catalytic converter can advantageously be determined in an indirect manner and nevertheless comparatively accurately. In this case, according to the invention, a "partial volume" (ie the second portion) of the exhaust gas catalytic converter is coated with an oxygen-storing material.

For example, an upstream or a downstream "catalyst disk" of the catalytic converter can be coated according to the invention, which therefore optionally corresponds to the second section. The oxygen storage capacity (OSC) is thus designed such that aging processes and deactivation processes, in particular in the second section, are related to the activity of the catalyst property to be monitored (in particular an HC conversion or a NO oxidation capability).

In this case, according to the invention, the fact that the oxygen storage capacity reacts more sensitively with respect to aging or poisoning of the catalytic converter than the actual function of the catalytic pollutant conversion is utilized. The oxygen storage capacity thus serves as a measure of the damage to the catalytic converter. This allows a particularly accurate and efficient monitoring of the catalytic converter or its operation.

As already explained above, according to the invention, the catalytic converter is an oxidation catalytic converter, DOC, a NOx storage catalytic converter, NSC, a selective catalytic reduction catalyst, SCR, or a diesel particulate filter with a catalytic coating. Therefore, if appropriate, the invention can also be used simultaneously for a plurality of exhaust gas components of the exhaust system, whereby monitoring of the exhaust system can be improved and expenditure and costs can be saved.

Preferably, the second portion is fluidly disposed adjacent to the first portion. This results in a particularly fast and accurate evaluation of the catalytic properties of the first section allows, whereby the exhaust gas catalyst according to the invention is improved.

Furthermore, it can be provided that a third section is arranged fluidically between the first section and the second section, which section has neither an oxygen storage capacity nor a catalytic capability. The third section can be, for example, a pipe of an exhaust gas channel of the exhaust system. In general, the invention enables a separation between the first section to be monitored and the second section having the oxygen storage capability. Both sections can therefore be operated independently of each other, in principle.

Thus, for example, the invention may be used for monitoring NO oxidation in an oxidation catalyst (eg, for so-called "feed gas generation" for a downstream SCR catalyst, SCR. In addition, the invention may also be used for monitoring a coated diesel particulate filter in terms of its ability to react hydrocarbons (HC), or even so-called "non-methane hydrocarbons" (NMHC). Likewise, according to the invention, monitoring of the SCR catalytic converter or monitoring of the NOx storage catalytic converter is possible or conceivable.

• – Betreiben der Brennkraftmaschine in einem ersten Betriebszustand, welcher dazu geeignet ist, einen in dem zweiten Abschnitt gespeicherten Sauerstoff freizusetzen;
• – Betreiben der Brennkraftmaschine in einem zweiten Betriebszustand, welcher dazu geeignet ist, in dem zweiten Abschnitt Sauerstoff zu speichern;
• – Auswerten der erfassten Temperatur und/oder des zeitlichen Verlaufs der erfassten Temperatur mindestens in dem zweiten Betriebszustand.

Furthermore, the invention relates to a first method for operating an exhaust gas catalytic converter for an internal combustion engine in which a first portion of the catalytic converter catalytically changes an exhaust gas of the internal combustion engine, a second portion of the catalytic converter stores oxygen at least temporarily, and a temperature downstream of and adjacent to the second portion is detected. The method comprises the following steps:

• - Operating the internal combustion engine in a first operating state, which is adapted to release an oxygen stored in the second section;
• Operating the internal combustion engine in a second operating state, which is suitable for storing oxygen in the second section;
• - Evaluate the detected temperature and / or the time course of the detected temperature at least in the second operating state.

Preferably, a fuel-air mixture of the internal combustion engine in the first operating state has an air shortage (so-called rich operation), and in the second operating state an excess air (so-called lean operation).

By the method according to the invention a particularly simple and at the same time accurate monitoring of the catalytic converter is made possible with respect to the catalytic properties of the first section. Furthermore, the inventive method is particularly "robust", since preferably only an evaluation of the temperature is required.

• – Ausgeben einer Warnmeldung;
• – Durchführen eines Eintrags in einen Fehlerspeicher für die Brennkraftmaschine;
• – Verändern eines Betriebszustands der Brennkraftmaschine.

In one embodiment of the method, the temperature and / or the temporal course of the temperature is compared with at least one threshold value, and at least one of the following steps is carried out, depending on the comparison:

• - issue a warning message;
• - Performing an entry in a fault memory for the internal combustion engine;
• - Changing an operating condition of the internal combustion engine.

As a result, the method according to the invention can give clear indications of an operating state of the exhaust gas catalytic converter identified as faulty. Optionally, the method may even take a countermeasure to keep the harmful emissions generated by the operation of the internal combustion engine relatively low, despite the error.

Furthermore, the accuracy of the method can be improved if the at least one threshold value is predefined using a measurement and / or using a data model. In addition, robustness of the method can be enhanced if the determined temperature profile or a temperature characterizing signal is filtered using a bandpass function. As a result, any possible interference signals can advantageously be reduced or eliminated. The bandpass filter is preferably designed such that it preferably allows passage of frequency ranges which are related to the heat release in the exhaust gas catalytic converter.

• – Betreiben der Brennkraftmaschine in einem ersten Betriebszustand, welcher dazu geeignet ist, einen in dem zweiten Abschnitt gespeicherten Sauerstoff freizusetzen;
• – Betreiben der Brennkraftmaschine in einem zweiten Betriebszustand, welcher dazu geeignet ist, in dem zweiten Abschnitt Sauerstoff zu speichern;
• – Auswerten einer Sauerstoffmenge und/oder eines Zeitverlaufs der Sauerstoffmenge in dem Abgas mindestens in dem zweiten Betriebszustand.

Furthermore, the invention relates to a second method for operating an exhaust gas catalytic converter for an internal combustion engine in which a first portion of the catalytic converter catalytically changes an exhaust gas of the internal combustion engine, a second portion of the catalytic converter stores oxygen at least temporarily, and an amount of oxygen downstream of and adjacent to the second portion is detected, the method comprising the following steps:

• - Operating the internal combustion engine in a first operating state, which is adapted to release an oxygen stored in the second section;
• - Operating the internal combustion engine in a second operating state, which is suitable is to store oxygen in the second section;
• - Evaluating an amount of oxygen and / or a time course of the amount of oxygen in the exhaust gas at least in the second operating state.

Preferably, the amount of oxygen or the time profile of the amount of oxygen is determined by means of a lambda probe. The second method presented here can be carried out in addition or as an alternative to the described first method. As a result, an accuracy can be improved and the method can be carried out comparatively easily and inexpensively.

• – einem Betriebszustand der Brennkraftmaschine;
• – einem Abgasmassenstrom der Brennkraftmaschine;
• – mindestens einer Temperatur in einer Abgasanlage für die Brennkraftmaschine;
• – einer Temperatur der Brennkraftmaschine;
• – einem Umgebungsluftdruck; und/oder
• – einer Umgebungstemperatur.

In one embodiment of the first or second method, this is started as a function of at least one of the following variables:

• - An operating condition of the internal combustion engine;
• An exhaust gas mass flow of the internal combustion engine;
• - At least one temperature in an exhaust system for the internal combustion engine;
• - a temperature of the internal combustion engine;
• An ambient air pressure; and or
• - an ambient temperature.

With this embodiment, particularly suitable conditions can be specified in particular for a start of the method, whereby its accuracy can be increased.

Furthermore, the invention relates to a control and / or regulating device for the internal combustion engine, wherein the control and / or regulating device is adapted to perform a method according to the embodiments described above.

Further information on the invention:

In order to determine the oxygen storage capacity in the second section, it is necessary to empty the oxygen previously stored in the second section. This is preferably done by providing a rich gas in the exhaust gas. The use of rich gas is essentially known from the regeneration of NOx storage catalysts. Subsequently, when (comparatively suddenly) the internal combustion engine is operated in a lean operation, the oxygen storage sites can be refilled with oxygen. The thereby occurring oxygen binding is an exothermic process, which can be measured very easily via the temperature sensor according to the invention.

Insofar as the oxygen storage capacity falls below a threshold value, which is determined by correlation with an exothermic release, it can be inferred according to the invention from a critical decrease of a catalyst efficiency (that is to say, for example, based on the HC conversion or the NO oxidation capacity). The delivery of a warning message (for example, on the dashboard of a motor vehicle) and / or the implementation of any countermeasures is possible.

To evaluate the heat release described above, the temperature profile behind the second section ("monitoring volume") is determined during the transition from rich operation to lean operation and a specific time thereafter. Herein, the heat release may be evaluated in terms of a difference of the temperature detected by the temperature sensor to a reference temperature (for example, a modeled temperature without heat release by oxygen storage based on the measured or modeled temperature upstream of the monitoring volume). This can be done, for example, by integration of the calculated with the aid of the described temperature difference and an exhaust gas mass flow amount of heat.

Another possibility is to evaluate a gradient of the temperature. The change in the temperature downstream of the monitoring volume is limited by a heat capacity of the catalytic converter. The release of heat in the oxygen storage takes place throughout the catalytic converter, so that the temperature behind the second section (if the second section is essentially functional) changes comparatively quickly. Thus, if a time derivation of the temperature in a monitoring period is greater than the threshold value described above, it can be concluded according to the invention that a functional second section and thus a functional first section and thus an overall functional catalytic converter are functioning.

Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. In the drawing show:

1 a simplified scheme for an internal combustion engine and an exhaust system therefor;

2 a simplified diagram for a first embodiment of an exhaust gas catalyst for the exhaust system of 1 ;

3 a simplified diagram for a second embodiment of the catalytic converter;

4 a simplified diagram for a third embodiment of the catalytic converter;

5 a simplified diagram for a fourth embodiment of the catalytic converter;

6 a time chart with operating variables of the exhaust system; and

7 a flowchart for a method for operating the catalytic converter.

The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments.

1 shows in the lower part of the drawing a simplified scheme of an exhaust system 10 of a motor vehicle. Left above the exhaust system 10 is an internal combustion engine 12 symbolically represented by a pipe connection 14 Exhaust gas in the exhaust system 10 flows.

A control and / or regulating device 16 is about incoming and outgoing electrical wiring 20 and 22 with the internal combustion engine 12 as well as incoming and outgoing electrical lines 24 and 26 with components of the exhaust system 10 connected. The compounds are merely indicated in the drawing. Furthermore, the control and / or regulating device comprises 16 a computer program 18 , In particular, the control and / or regulating device 16 trained to be one below at the 6 and 7 to carry out the described method.

In the exhaust system 10 from 1 the exhaust gas is passed through substantially from left to right and prepared. In the present case, it is the exhaust system 10 a diesel vehicle. The exhaust system 10 points to this in a flow direction (arrow 27 ) of the exhaust gas an oxidation catalyst 28 (in this case, a diesel oxidation catalyst, DOC), a diesel particulate filter 30 , a NOx storage catalyst 32 , (NSC, "NOx storage-reduction catalyst") and an outlet 34 on.

In particular, the oxidation catalyst 28 and the NOx storage catalyst 32 adapted to an exhaust gas of the internal combustion engine 12 to change catalytically. This relates in particular to an oxidation of hydrocarbons (HC) present in the exhaust gas. Likewise, the diesel particulate filter 30 a catalytic coating which has the ability to oxidize hydrocarbons.

Furthermore, the exhaust system includes 10 a plurality of probes and / or sensors, which operating values of the exhaust system 10 determine and to the control and / or regulating device 16 to transfer. Representing is in the 1 one temperature sensor each 38a respectively. 38b respectively. 38c downstream of the oxidation catalyst, respectively 28 or the diesel particulate filter 30 or the NOx storage catalyst 32 drawn.

Also includes the exhaust system 10 a lambda probe 39 , which in the present case downstream of the diesel particulate filter 30 is arranged. In not shown embodiments of the exhaust system 10 is the lambda sensor 39 upstream of the oxidation catalyst 28 or downstream of the oxidation catalyst 28 or downstream of the NOx storage catalyst 32 arranged.

The aforementioned catalytic converters are in the 1 each shown only in a general embodiment. Inventive embodiments of the oxidation catalyst 28 or the diesel particulate filter 30 or the NOx storage catalyst 32 be in the following 2 to 5 to be shown.

In operation of the internal combustion engine 12 the exhaust gas is through the pipe connection 14 to exhaust system 10 directed. In the oxidation catalyst 28 In particular, hydrocarbons (HC) are oxidized so that hydrocarbon emissions at the outlet 34 do not exceed a predetermined limit value (the so-called OBD limit value or on-board diagnostics). In the NOx storage catalyst 32 In particular, nitrogen oxides (NOx) are catalytically altered so that nitrogen oxide emissions at the outlet 34 do not exceed a given (OBD) limit.

2 shows a highly simplified scheme for a first embodiment of an exhaust gas catalyst, such as the oxidation catalyst 28 from 1 , The oxidation catalyst 28 includes a housing 40 and in the direction of the arrows 27 an upstream exhaust passage 42 and a downstream exhaust passage 44 , The exhaust gas thus flows in the drawing from left to right through the oxidation catalyst 28 ,

In one in the 2 right area of the housing 40 includes the oxidation catalyst 28 a first section 46 , which the exhaust gas of the internal combustion engine 12 can change catalytically, in particular with respect to hydrocarbons (HC). Furthermore, the oxidation catalyst comprises 28 in one in the 2 left area of the housing 40 a second section 48 , which is adapted to store oxygen at least temporarily.

Downstream of and adjacent to the second section 48 is a temperature sensor 38 arranged, so for example the temperature sensor 38a from 1 ,

In the embodiment of 2 is the first section 46 so downstream of the second section 48 arranged. In particular, is the second section 48 fluidic to the first section 46 arranged immediately adjacent.

Furthermore, the second section 48 at least partially an oxygen-storing coating, wherein the oxygen-storing coating comprises a cerium oxide material and / or a cerium / zirconium mixed oxide material and / or a praseodymium oxide material and / or a neodymium oxide material. In the present case, the second section comprises 48 additionally a platinum material. In an alternative embodiment, the second section comprises 48 additionally a palladium material.

The second section 48 is formed such or the second portion comprises such a material that an oxygen storage capacity of the second portion 48 with a catalytic capability of the first section 46 is correlated. The Oxygen Storage Capacity (OSC) of the second section 48 is thus designed such that aging processes and deactivation processes in the oxidation catalyst 28 in a relationship to the activity of the catalyst property to be monitored (in the present case an HC conversion) of the first section 46 stand.

It is understood that the representations of 2 to 5 not just as described on the oxidation catalyst 28 , but also on the NOx storage catalyst 32 (NSC) are applicable. If the diesel particulate filter 30 has a catalytic coating, are the 2 to 5 also on the diesel particulate filter 30 applicable. Also in the 1 not shown catalytic converter for a selective catalytic reduction, SCR, according to the 2 to 5 be executed.

3 shows a second embodiment of the oxidation catalyst 28 , This is the second section 48 of the oxidation catalyst 28 downstream of the first section 46 arranged.

4 shows a third embodiment of the oxidation catalyst 28 , The present is fluidly between the first section 46 and the second section 48 a third section 50 which has neither an oxygen storage ability nor a catalytic ability.

The third section 50 of the oxidation catalyst 28 from 4 is designed as a tubular exhaust passage, whereby the oxidation catalyst 28 comprises two, in principle, separate components. A first component (upstream) comprises a housing 40a and the second section 48 , A second component (downstream) comprises a housing 40b and the first section 46 , The temperature sensor 38 is at the third section 50 downstream of the second section 48 arranged.

5 shows a fourth embodiment of the oxidation catalyst 28 , where, similar to the 4 , in the direction of the flowing exhaust gas first, the second section 48 , then the third section 50 , and then the first section 46 flows through the exhaust gas. Unlike the 4 is the third section 50 but not carried out by means of a separate pipe, but is in an axially approximately central region of the housing 40 of the oxidation catalyst 28 arranged.

6 shows a timing diagram with three in the drawing vertically stacked coordinate systems. All three coordinate systems have an equal time scale t. The upper coordinate system is characterized by a curve 52 an operating condition of the internal combustion engine 12 , A value "F" characterizes a rich operation, and a value "M" respectively characterizes a lean operation of the internal combustion engine 12 ,

The middle coordinate system shows according to the through the curve 52 characterized operating state an associated curve 54 for a time course of a lambda value λ upstream of the second section 48 , A horizontal dashed line corresponds to a lambda value of 1.

The lower coordinate system shows two time histories for one temperature 55 which is downstream of the second section 46 by means of the temperature sensor 38 respectively. 38a respectively. 38b respectively. 38c is recorded or can be detected. An upper first bend 56 shows the time course of the temperature 55 if the second section 48 has a comparatively large oxygen storage capacity. A lower second curve 58 shows the time course of the temperature 55 if the second section 48 has a comparatively small oxygen storage capacity.

A vertical dashed line 60 characterized jointly for all three coordinate systems of 6 a time t0, to which the rich operation of the internal combustion engine 12 is ended. Thereafter, an evaluation of the time course of the temperature 55 begin according to the lower third coordinate system.

In a first embodiment, the detected temperature 55 , starting from the time t0 to a subsequent time t1, integrated. A result of the integration can then be compared with a first predefinable threshold, whereby an evaluation of the state of the second section 46 is possible.

In a second embodiment, the detected temperature 55 , starting from the time t0, continuously integrated. If a result of the integration reaches a second predefinable threshold, an associated time t2 is determined. A time difference t2-t0 is then compared with a third predefinable threshold, whereby an evaluation of the state of the second section 46 is possible.

In a third embodiment, an amount of oxygen in the exhaust gas by means of the lambda probe 39 determined and continuously integrated starting from the time t0. The amount of oxygen integrated in this way can be comparable to the integrated temperature 55 of the first or the second embodiment are evaluated.

Because according to the invention, the oxygen storage capacity of the second section 48 with the catalytic capability of the first section 46 Thereafter, for each of the three embodiments, the state of the first section may be correlated 46 and thus to the state of the oxidation catalyst 28 to be closed altogether.

7 shows a flowchart for a method for operating the internal combustion engine 12 , In a starting block 62 starts in the 7 presented procedure.

In a following block 64 becomes the internal combustion engine 12 operated in a first operating state, which is suitable, one in the second section 48 release stored oxygen; Preferably, the internal combustion engine 12 operated for a first period of time in a rich operation. In a following block 66 becomes the internal combustion engine 12 operated in a second operating state, which is suitable in the second section 48 To store oxygen; Preferably, the internal combustion engine 12 while operating in a lean operation, compare the value "M" in the upper coordinate system of 6 , A transition from the first operating state to the second operating state is in the 6 through the dashed line 60 characterized.

In a following block 68 there is a detection of the temperature 55 according to the at 6 described first or second embodiment. Additionally or alternatively, in the block 68 a determination of the amount of oxygen corresponding to that in the 6 described third embodiment.

In a following block 70 an evaluation of the detected temperature takes place 55 and / or the time course of the detected temperature 55 at least in the second operating state. In addition or alternatively, in block 70 also evaluating the in the block 68 determined amount of oxygen (or a time course of the amount of oxygen) take place, as described above.

In addition, the determined course of the temperature 55 or the temperature 55 characterizing signal are filtered using a bandpass function. Comparable filtering is also possible in relation to the (alternative or supplementary) determined amount of oxygen.

This is the temperature 55 or the time course of the temperature 55 or the amount of oxygen or the time course of the amount of oxygen compared with at least one threshold, as described above in the three embodiments of 6 also already described. Preferably, the at least one threshold is predetermined using a measurement and / or using a data model. Thus, the state of, for example, the oxidation catalyst 28 getting closed.

• – Ausgeben einer Warnmeldung;
• – Durchführen eines Eintrags in einen Fehlerspeicher für die Brennkraftmaschine 12;
• – Verändern eines Betriebszustands der Brennkraftmaschine 12.

In a following block 72 will depend on the one in the block 70 if appropriate, at least one of the following steps:

• - issue a warning message;
• - Performing an entry in a fault memory for the internal combustion engine 12 ;
• - Changing an operating condition of the internal combustion engine 12 ,

In an endblock 74 ends the means of 7 described procedure. It is understood that the method described occasionally or periodically during operation of the internal combustion engine 12 can be repeated.

In addition, this can be done by means of 6 and or 7 described method depending on so-called "release conditions" are performed:
For example, the evaluation of the temperature 55 and the time-going rich operation of the internal combustion engine 12 only started when a present operating state of the internal combustion engine 12 (or other conditions necessary for the procedure) are suitable for a meaningful monitoring result. In addition to predetermined minimum / maximum thresholds for environmental conditions (such as an ambient pressure, an ambient temperature and / or a temperature of the internal combustion engine 12 , etc.) can be conditions for the temperature 55 the catalytic converter (for example, a temperature 55 upstream and / or downstream of the catalytic converter and / or within the housing 40 , in each case measured or determined by means of a data model). Other possible release conditions for the method may be with respect to one through the exhaust system 10 be given flowing exhaust gas mass flow.

It may be another objective of the described release conditions, the emission of the emptying of the oxygen storage in the second section 48 to minimize the required rich operation or to perform the emptying (only) when an operation of the internal combustion engine 12 is unlikely to be adversely affected or only marginally affected.

Other embodiments of the method may be, for example:
The emptying (regeneration) of the oxygen storage can be started specifically as described above. Should be operational anyway an operating condition of the internal combustion engine 12 with rich exhaust gas composition, then the process can also be carried out following the operational fat operation. Examples of this are load surges or an already required temporary rich operation for a regeneration of the NOx storage catalytic converter 32 , The above monitoring options can also be combined. During regeneration (rich operation) can in this case all the oxygen storage of the exhaust system 10 simultaneously emptied and then the evaluation of the invention are started.

Claims (14)

Catalytic converter ( 28 ; 30 ; 32 ) for an internal combustion engine ( 12 ), wherein the catalytic converter ( 28 ; 30 ; 32 ) is adapted to an exhaust gas of the internal combustion engine ( 12 ) catalytically, characterized in that the exhaust gas catalyst ( 28 ; 30 ; 32 ) at least a first section ( 46 ), which can catalytically change the exhaust gas, and that the catalytic converter ( 28 ; 30 ; 32 ) at least a second section ( 48 ), which is adapted to store oxygen at least temporarily, and that downstream of and adjacent to the second section (FIG. 48 ) at least one temperature sensor ( 38 . 38a . 38b . 38c ) is arranged. Catalytic converter ( 28 ; 30 ; 32 ) according to claim 1, characterized in that the second section ( 48 ) at least partially comprises an oxygen-storing coating, wherein the oxygen-storing coating comprises a cerium oxide material and / or a cerium / zirconium mixed oxide material and / or a praseodymium oxide material and / or a neodymium oxide material. Catalytic converter ( 28 ; 30 ; 32 ) according to at least one of the preceding claims, characterized in that the second section ( 48 ) additionally comprises a platinum material or a palladium material. Catalytic converter ( 28 ; 30 ; 32 ) according to at least one of the preceding claims, characterized in that the second section ( 48 ) is formed and / or that the second section ( 48 ) comprises a material such that an oxygen storage capacity of the second section ( 48 ) with a catalytic capability of the first section ( 46 ) is correlated. Catalytic converter ( 28 ; 30 ; 32 ) according to at least one of the preceding claims, characterized in that the catalytic converter ( 28 ; 30 ; 32 ) an oxidation catalyst ( 28 ), DOC, a NOx storage catalyst ( 32 ), NSC, a selective catalytic reduction catalyst, SCR, or a diesel particulate filter ( 30 ) with a catalytically active coating. Catalytic converter ( 28 ; 30 ; 32 ) according to at least one of the preceding claims, characterized in that the second section ( 48 ) fluidly to the first section ( 46 ) is arranged immediately adjacent. Catalytic converter ( 28 ; 30 ; 32 ) according to at least one of claims 1 to 5, characterized in that fluidically between the first section ( 46 ) and the second section ( 48 ) a third section ( 50 ) having neither an oxygen storage ability nor a catalytic ability. Method for operating an exhaust gas catalytic converter ( 28 ; 30 ; 32 ) for an internal combustion engine ( 12 ), in which a first section ( 46 ) of the catalytic converter ( 28 ; 30 ; 32 ) an exhaust gas of the internal combustion engine ( 12 ) catalytically altered, a second section ( 48 ) of the catalytic converter ( 28 ; 30 ; 32 ) Stores oxygen at least temporarily, and downstream of and adjacent to the second section (FIG. 48 ) a temperature ( 55 ), characterized in that the method comprises the following steps: - operating the internal combustion engine ( 12 ) in a first operating state, which is suitable, one in the second section ( 48 release released oxygen; - Operating the internal combustion engine ( 12 ) in a second operating state, which is suitable in the second section ( 48 ) To store oxygen; - Evaluation of the detected temperature ( 55 ) and / or the time course of the detected temperature ( 55 ) at least in the second operating state. Method according to claim 8, characterized in that the temperature ( 55 ) and / or the time course of the temperature ( 55 ) is compared with at least one threshold value, and that, depending on the comparison, at least one of the following steps is performed: issuing a warning message; - Performing an entry in a fault memory for the internal combustion engine ( 12 ); - changing an operating state of the internal combustion engine ( 12 ). A method according to claim 9, characterized in that the at least one threshold value is predetermined by using a measurement and / or using a data model. Method according to at least one of claims 8 to 10, characterized in that the determined course of the temperature ( 55 ) or the temperature ( 55 ) is filtered using a bandpass function. Method for operating an exhaust gas catalytic converter ( 28 ; 30 ; 32 ) for an internal combustion engine ( 12 ), in which a first section ( 46 ) of the catalytic converter ( 28 ; 30 ; 32 ) an exhaust gas of the internal combustion engine ( 12 ) catalytically altered, a second section ( 48 ) of the catalytic converter ( 28 ; 30 ; 32 ) Stores oxygen at least temporarily, and downstream of the second section (FIG. 48 ) an amount of oxygen is detected, characterized in that the method comprises the following steps: - operating the internal combustion engine ( 12 ) in a first operating state, which is suitable, one in the second section ( 48 release released oxygen; - Operating the internal combustion engine ( 12 ) in a second operating state, which is suitable in the second section ( 48 ) To store oxygen; - Evaluating the amount of oxygen and / or a time course of the amount of oxygen in the exhaust gas at least in the second operating state. Method according to at least one of claims 8 to 12, characterized in that it is started as a function of at least one of the following variables: - an operating state of the internal combustion engine ( 12 ); An exhaust gas mass flow of the internal combustion engine ( 12 ); - at least one temperature ( 55 ) in an exhaust system ( 10 ) for the internal combustion engine ( 12 ); A temperature of the internal combustion engine ( 12 ); An ambient air pressure; and / or - an ambient temperature. Control and / or regulating device ( 16 ) for an internal combustion engine ( 12 ), characterized in that the control and / or regulating device ( 16 ) is adapted to perform a method according to at least one of claims 8 to 13.

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