DE102020103894A1 - Method for monitoring the regeneration of a gasoline particle filter - Google Patents

Abstract

A method for monitoring the regeneration of a particle filter which is arranged in an exhaust system of a gasoline engine, comprising at least the following steps: a) determining according to which regeneration stage of a defined number of regeneration stages the particle filter is being regenerated or was last regenerated; b) detecting a measure for at least one first test criterion, which is characteristic of a change in the loading of the particle filter, c) check whether the first test criterion is met, and change to a higher regeneration level if the first test criterion is not met, and change to a lower regeneration level or maintain the current one Regeneration level when the first test criterion is met.

Description

The invention relates to a method for monitoring the regeneration of a (gasoline) particle filter which is arranged in an exhaust system of a gasoline engine, a computer program for carrying out the method, a machine-readable storage medium on which the computer program is stored, and a vehicle with a gasoline engine and a system for carrying out the procedure.

The method described here and the vehicle described here relate to a vehicle with a gasoline particulate filter unit installed in the exhaust system. The background to the use of a gasoline particulate filter (OPF) is the increasingly stringent exhaust gas standards around the world, which are accompanied by a steady reduction in emissions from an internal combustion engine and, in particular, from a gasoline internal combustion engine (Otto engine). These include the number of particles and the particle mass. In addition, new dimensioning cycles (e.g. WLTP) and the introduction of RDE measurements represent an increased requirement for compliance with the limit values for particle number and particle mass. These changes will probably make the use of a particle filter in gasoline engines unavoidable in the medium term.

A gasoline particulate filter cleans the exhaust gas in particular by trapping particles in the exhaust gas, such as fine dust. So that the gasoline particulate filter can preferably continuously fulfill this task, the soot deposited in the gasoline particle filter should be burned free from a certain amount so that the gasoline particle filter does not become clogged. Depending on the positioning of the gasoline particulate filter (proximity to the combustion engine) and the driving style (especially vehicle speed and / or acceleration behavior), the (unaffected) exothermicity of the exhaust gas mass flow may be too low to allow the gasoline particle filter to reach the desired regeneration temperature (approx. 550 ° C). to heat up. In such cases, separate engine and / or extra-engine measures can be initiated that support the heating process and also provide sufficient oxygen for the soot oxidation. Under certain circumstances, this is accompanied by a deterioration in consumption and emissions.

From the EP 1 170 473 A1 it is known to use a particle filter in connection with an Otto engine. There, for the controlled regeneration of the particle filter, the loading state of the particle filter is continuously monitored via the current flow resistance of the particle filter.

From the US 8,966,882 B2 a differential pressure-based activation of a particulate filter diagnosis of a diesel particulate filter is known. One focus of the method there is on detecting a malfunction of the differential pressure sensor in order to avoid unnecessary replacement of the diesel particle filter as far as possible.

From the US 7,536,854 B2 a method for regenerating a diesel particulate filter is known. The regeneration should be controlled in such a way that thermal overloading of the diesel particle filter is avoided as far as possible.

The known methods are thus primarily concerned with the control of the regeneration as such or the regeneration process as such or with the detection of damage to the particle filter or the associated sensor system. With the known methods, however, the efficiency of the regeneration, in particular the regeneration measures or the regeneration strategy of an Otto particle filter, cannot be monitored or at least insufficiently and in particular not independently of the control of the regeneration as such or the regeneration process as such. For example, a so-called permanent regeneration cannot be recognized and / or switched off with the known methods.

Proceeding from this, it is an object of the invention to at least partially solve the problems described in connection with the prior art. In particular, a method for monitoring the regeneration of an Otto particle filter is to be specified, by means of which the efficiency of the regeneration, in particular the regeneration measures or the regeneration strategy of the Otto particle filter, can be monitored. In addition, a permanent regeneration by means of the method should preferably be recognizable and possibly even avoidable.

These objects are achieved by the features of the independent patent claims. Further advantageous configurations of the solution proposed here are specified in the dependent claims. It should be pointed out that the features listed individually in the dependent claims can be combined with one another in any desired, technologically sensible manner and define further embodiments of the invention. In addition, the features specified in the patent claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

1. a) Ermitteln gemäß welcher Regenerationsstufe einer definierten Anzahl an Regenerationsstufen der Partikelfilter regeneriert wird oder zuletzt regeneriert wurde;
2. b) Erfassen eines Maßes für zumindest ein erstes Prüfkriterium, welches für eine Änderung der Beladung des Partikelfilters charakteristisch ist,
3. c) Prüfen, ob das erste Prüfkriterium erfüllt wird, und Wechseln in eine höhere Regenerationsstufe, wenn das erste Prüfkriterium nicht erfüllt wird, und Wechseln in eine niedrigere Regenerationsstufe oder beibehalten der momentanen Regenerationsstufe, wenn das erste Prüfkriterium erfüllt wird.

To this end, a method for monitoring the regeneration of a particle filter, which is in a Exhaust system of a gasoline engine is arranged at, comprising at least the following steps:

1. a) determining according to which regeneration stage of a defined number of regeneration stages the particle filter is being regenerated or was last regenerated;
2. b) detecting a measure for at least one first test criterion which is characteristic of a change in the loading of the particle filter,
3. c) Check whether the first test criterion is met, and change to a higher regeneration level if the first test criterion is not met, and change to a lower regeneration level or maintain the current regeneration level if the first test criterion is met.

Steps a), b) and c) can, for example, be carried out at least once in the specified order. Furthermore, steps a), b) and c) can be carried out at least partially in parallel or simultaneously. The method can in particular be carried out with a system, also described here, for monitoring the regeneration of the particle filter of a vehicle.

The method is used in particular to monitor the efficiency of the regeneration strategy or the regeneration method by means of which the particle filter is cleaned (continuously or discontinuously) during operation of the exhaust system. The regeneration process controls, for example, the regeneration measures for the particle filter. The regeneration measures can include, for example, heating up the particle filter (by heating up the exhaust gas) and / or providing (more) oxygen (in the exhaust gas). The regeneration method usually runs independently of or at least partially in parallel with the method described here for monitoring the regeneration of the particle filter. The method for monitoring the regeneration of the particle filter can, however, if necessary, in particular if a test criterion is not met, influence the regeneration method or intervene in it from outside. The regeneration process is usually operated as a function of loading levels (or as a function of the current loading state and / or loading wheel) and / or regeneration levels. Loading levels can be understood to mean, in particular, defined loading conditions and / or loading levels. For example, five, six or more loading stages and / or regeneration stages can be provided. Furthermore, the number of loading levels can correspond to the number of regeneration levels. The current loading level of the particle filter can be determined by sensors and / or by computer, for example. The regeneration process can select the regeneration stage, for example, as a function of the loading stage. For example, the regeneration process can increase the regeneration level when the loading level increases. Accordingly, the regeneration method can reduce the regeneration level, for example, when the loading level is reduced. During the operation of the exhaust system with a corresponding regeneration process it can happen that the particle filter is operated over a longer period of time with the same loading level or the same regeneration level. This can result, for example, from the fact that comparatively less intensive regeneration measures are carried out continuously. A corresponding mode of operation can also be referred to as so-called permanent regeneration. However, it has been found that with such a permanent regeneration, a (comparatively higher) deterioration in consumption and emissions can be expected overall (over the entire operating period). The method described here for monitoring the regeneration of the particle filter can advantageously contribute to recognizing or identifying corresponding permanent regenerations and, if necessary, influencing the regeneration method in such a way that permanent regeneration can be ended or avoided as far as possible. For this purpose, the regeneration level can be increased, for example (artificially or externally), in particular to a level which is higher than the current loading level of the particle filter. This can help to accelerate the change in the loading of the particle filter or to increase its (negative) slope, in particular to return to a lower loading level (and regeneration level). As an alternative or cumulative to the detection of a possible permanent regeneration, the method described here can also advantageously (generally) contribute to system errors, in particular to detect a (possible) presence of one or more defective components of the system, which can have a negative effect on the regeneration.

In step a) it is determined according to which regeneration stage of a defined or predetermined number of regeneration stages the particle filter is regenerated or was last regenerated. For example, four, five, six or more regeneration stages can be provided or set up as a defined number. The regeneration stages are usually determined by a regeneration process (ie without intervention by the method described here for monitoring the regeneration of the particle filter). It can (thus) be determined in step a), for example, in which regeneration stage the regeneration process is currently or was last. Furthermore, in time before or in step a) and / or between steps a) and b) check one or more prerequisites, such as a sufficient exhaust gas mass flow, a sufficient exhaust gas temperature, a sufficient oxygen mass flow and / or the presence of a predeterminable minimum regeneration stage.

In step b), a measure for at least one first test criterion is measured, which is characteristic of a change in the loading of the particle filter. The detection can take place, for example, by means of sensors and / or computationally. For example, a change in pressure difference and / or a change in the composition of the exhaust gas can be detected via the particle filter as a measure of a change in the loading of the particle filter. As a measure for a change in the loading of the particle filter, a step change (the loading step or regeneration step) within the (unaffected) regeneration process (during a driving cycle) can alternatively or cumulatively be taken into account.

The first test criterion can be used, for example, to test whether the change in the loading of the particle filter is sufficient or corresponds to an expected value (for the regeneration stage under consideration). In this context, it can be checked, for example, whether the increase in the change in the loading of the particle filter is sufficient. In this context, positive and negative slopes can basically be taken into account, since, for example, a sufficient positive increase can also allow a conclusion to be drawn that the loading of the particle filter builds up sufficiently quickly, in particular to prevent permanent regeneration. The first test criterion (however) preferably serves to test whether the loading of the particle filter is decreasing (sufficiently quickly and / or strongly). In this context, the first test criterion can be used, for example, to test whether a loading quotient has fallen (sufficiently quickly and / or strongly).

The first test criterion can also include several sub-criteria, for example. A first sub-criterion can consist, for example, of whether a step change has taken place (within a driving cycle). An alternative or further sub-criterion can consist, for example, of whether a change in load has taken place (within a driving cycle). An alternative or further sub-criterion can consist, for example, in whether one or more of the aforementioned sub-criteria are not met over a predeterminable (minimum) number of driving cycles. An alternative or further sub-criterion can consist, for example, in whether a certain (minimum) loading level or regeneration level and / or the same loading level or regeneration level is present over a predeterminable (minimum) number of driving cycles.

In step c) it is checked whether the first test criterion is met, and a switch is made to a higher regeneration level (with more intensive regeneration measures compared to the previous regeneration level) if the first test criterion is not met, and a change to a lower regeneration level or the current regeneration level is retained, if the first test criterion is met. The higher regeneration stage can be, for example, one with more intensive regeneration measures compared to the previous regeneration stage. The higher regeneration level can (alternatively) also be a level that requires a visit to the workshop. The change can take place, for example, by exactly one regeneration level or to the next higher regeneration level or the next lower regeneration level. A change in the regeneration level can in particular contribute to the fact that the current regeneration level is greater or smaller than the current loading level of the particle filter. The more intensive regeneration measures can include, for example, greater heating and / or an increase in the oxygen concentration in the exhaust gas.

According to an advantageous embodiment, it is proposed that the measure for the first test criterion is a measure for a change in pressure difference across the particle filter. For this purpose, for example, a measured value signal from a pressure difference sensor can be evaluated. In this context, the pressure difference sensor is usually arranged in the area of the particle filter. As an alternative, measured value signals from a pressure sensor upstream of the particle filter and from a pressure sensor downstream of the particle filter can also be evaluated, with the change in pressure difference across the particle filter being determined from the measured value signals.

According to a further advantageous refinement, it is proposed that the method further include a detection of a (thermal) measure for a second test criterion, which is characteristic of sufficient heating of the particle filter. The detection can take place, for example, by means of sensors and / or computationally. A temperature in the area of the particle filter, such as a particle filter temperature and / or an exhaust gas temperature, for example, can be recorded as a measure of sufficient heating of the particle filter. Alternatively or cumulatively, a (sufficient and / or positive) change in temperature can also be taken into account as a measure of sufficient heating of the particle filter.

According to a further advantageous embodiment, it is proposed that the measure for the second test criterion is a measure for a temperature (change) of the particle filter. A temperature (change) in the area of the particle filter, such as a particle filter temperature (change) and / or an exhaust gas temperature (change), for example, can serve as a measure of the temperature of the particle filter.

According to a further advantageous embodiment, it is proposed that the method further comprises checking whether the second test criterion is met, and changing to a higher regeneration stage (with more intensive heating measures compared to the previous regeneration stage) if the second test criterion is not met, and changing to a lower regeneration level or maintaining the current regeneration level if the second test criterion is met. The higher regeneration stage can be, for example, one with more intensive heating measures compared to the previous regeneration stage. The higher regeneration level can (alternatively) also be a level that requires a visit to the workshop. The second test criterion can for example be tested (in terms of time) at least partially in parallel or at the same time as the first test criterion. Alternatively or cumulatively, the second test criterion can be tested independently of or separately from the first test criterion. If the second test criterion is to be or will be tested, it can be tested (in terms of time) before the first test criterion, for example. The terms “first” and “second” test criteria therefore do not describe a temporal relationship, but rather serve to distinguish between test criteria that differ from one another. In particular, it can be sufficient if one of the two test criteria is not met in order to cause the regeneration level to be raised.

The second test criterion can be used, for example, to test whether the measure for the temperature of the particle filter corresponds to an expected value (for the regeneration stage under consideration). For example, it can be checked whether the particle filter temperature (change) has reached or exceeded a predeterminable threshold value. The second test criterion can in particular contribute to checking whether sufficient conditions exist for a regeneration of the particle filter, such as for example a burning off of soot.

The second test criterion can also include several sub-criteria, for example. A first sub-criterion can consist, for example, in whether or not a predeterminable minimum temperature (change) (within a driving cycle) was reached and / or was reached or not reached within a predeterminable (minimum) number of heating attempts. An alternative or further sub-criterion can consist, for example, in whether the aforementioned sub-criterion was met or not met within a predeterminable (minimum) number of driving cycles.

According to a further advantageous embodiment, it is proposed that at least if a partial criterion of the test criterion is not met (repeated and / or successive) within a regeneration stage or if there is a change to a higher regeneration stage, an error is suspected. The suspicion of a fault can be displayed to a driver of the vehicle, for example visually and / or acoustically. Alternatively or cumulatively, the suspected error can be read out during an analysis in a workshop. A repeated occurrence of the suspected fault over a predeterminable (minimum) number of driving cycles and / or in the same regeneration stage can represent a further sub-criterion of the test criterion.

According to a further advantageous embodiment, it is proposed that the suspicion of an error be confirmed and an error is set if a further sub-criterion of the test criterion is not met within a regeneration level or if the higher regeneration level is retained or a change is made to an even higher regeneration level in a subsequent test. The error can be displayed to a driver of the vehicle, for example visually and / or acoustically. The output of the error can cause a driver of the vehicle to visit a workshop, for example.

The consequence of a suspected error can thus be escalating into a higher regeneration level with more intensive measures. A regeneration can be carried out and assessed again at this stage. If the evaluation criteria are positive, you can switch back to a lower level. If an error is detected again, the suspected error can be confirmed and the error output. At the same time, it is possible to escalate again to a higher level. For example, when the vehicle has reached the highest regeneration level (for example, regeneration level five or six), it can be sent to a workshop for maintenance purposes.

According to a further aspect, a computer program for carrying out a method described here is proposed. In other words, this relates in particular to a computer program (product), comprising instructions which, when the program is executed by a computer, cause the computer to carry out a method described here.

According to a further aspect, a machine-readable storage medium is also proposed on which the computer program is stored. The machine-readable storage medium is usually a computer-readable data carrier.

According to a further aspect, a vehicle with an Otto engine, an exhaust system assigned to the Otto engine and a system for monitoring the regeneration of a particle filter which is arranged in the exhaust system is proposed. The system for monitoring the regeneration of the particle filter is set up to carry out a method described here. The system for monitoring the regeneration can, for example, access sensors of the exhaust system, such as a differential pressure sensor in the area of the particle filter and / or a temperature sensor in the area of the particle filter, and read in measured values therefrom. Furthermore, the system can include, for example, the machine-readable storage medium on which the computer program for carrying out the method is stored. To carry out the method, the system can furthermore comprise, for example, a processor (controller) and / or control device.

The exhaust system can further comprise a catalytic converter, such as a three-way catalytic converter. The catalyst can be arranged upstream or downstream of the particle filter. The particle filter can be coated or uncoated. Upstream of the catalytic converter and particle filter, an (exhaust gas) turbocharger can act on the exhaust gas flowing in the direction of the catalytic converter or the particle filter. A pressure difference sensor can be used in the area of the particle filter to detect a measure for the change in the loading of the particle filter. A pressure sensor upstream of the particle filter and a further pressure sensor downstream of the particle filter can also be used, a pressure difference change being determined from their measurement signals. Alternatively or cumulatively, lambda probes can be used upstream of the particle filter and downstream of the particle filter.

The details, features and advantageous configurations discussed in connection with the method can correspondingly also occur in the computer program, the storage medium and / or the vehicle presented here, and vice versa. In this respect, reference is made in full to the statements made there for a more detailed characterization of the features.

• 1: ein Ablaufdiagramm zur Veranschaulichung eines Ausführungsbeispiels des hier beschriebenen Verfahrens,
• 2: ein Ablaufdiagramm zur Veranschaulichung eines weiteren Ausführungsbeispiels des hier beschriebenen Verfahrens, und
• 3: ein hier beschriebenes Kraftfahrzeug.

The solution presented here and its technical environment are explained in more detail below with reference to the figures. It should be pointed out that the invention is not intended to be restricted by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in or in connection with the figures and to combine them with other components and / or findings from other figures and / or the present description. They show schematically:

• 1 : a flow chart to illustrate an embodiment of the method described here,
• 2 FIG. 3 shows a flow chart to illustrate a further exemplary embodiment of the method described here, and FIG
• 3 : a motor vehicle described here.

1 shows schematically a flowchart to illustrate an exemplary embodiment of the method described here for monitoring the regeneration of a particle filter which is arranged in an exhaust system of a gasoline engine.

The method starts here by way of example with block 101. In this, for example (according to step a)) it can be determined according to which regeneration stage of a defined number of regeneration stages the particle filter is being regenerated or was last regenerated. It can be provided, for example, that the process continues to block 102 only when a certain minimum regeneration level, such as from regeneration level two or regeneration level three (of a total of six regeneration levels, for example) has been reached.

In block 102, for example, a first sub-criterion of an exemplary first test criterion is checked Engine, so-called "start-stop" function (s) can be disregarded) a level change from one regeneration level to another regeneration level (up or down) has taken place. Such a step change can be characteristic of a change in the loading of the particle filter and consequently represent a measure for the first test criterion. This is because a step change is usually triggered by the regular regeneration process, which is monitored by the process described here, when the load has increased (significantly) or decreased (significantly). Thus, a step change can provide a conclusion about a proper, in particular efficient, functionality of the regular regeneration process. If there was no step change in a driving cycle, this can be, for example be a sign that the load has not increased (significantly) or decreased (significantly) and the particle filter is in a kind of permanent regeneration in which regeneration measures are active that (although) prevent a significant increase in the load, but also do not are sufficiently intense to cause a significant decrease in loading. However, it has been shown that with such a permanent regeneration, the permanent energy input consumes more energy overall than with other regeneration processes, which are desired here as examples (and referred to as "regular"), in which the load can first (significantly) increase and then with a time-limited energy input is again (significantly) reduced.

If a level change from one regeneration level to another regeneration level (upwards or downwards) has taken place in the current or most recently completed driving cycle, the first sub-criterion can be regarded as fulfilled and the method in block 104 can be ended or interrupted, for example at the beginning a new driving cycle can be restarted at block 101. Before ending in block 104, any counters that have already been set or changed (which will be discussed in more detail below) can be reset in block 103.

If, however, there has been no change in level from one regeneration level to another regeneration level in the current or most recently completed driving cycle, the first subcriterion cannot be regarded as fulfilled and the method can be continued with block 105.

In block 105, for example, a second sub-criterion of an exemplary first test criterion is checked. In this context, the second sub-criterion of the first test criterion is checked, for example, as to whether a significant change in the loading of the particle filter (up or down) has taken place in the current or most recently completed driving cycle. A change in pressure difference in the pressure difference across the particle filter, for example, can serve as a measure for the change in load, which can consequently also represent a measure for the first test criterion. A significant change in loading generally allows a conclusion to be drawn about the proper, in particular efficient, functionality of the regular regeneration process.

If there has been a significant change in load (upwards or downwards) in the current or most recently completed driving cycle, the second sub-criterion can be regarded as fulfilled and the method can be ended or interrupted in block 106, and for example with the start of a new driving cycle in block 101 started again.

However, if no significant change in load has taken place in the current or most recently completed driving cycle, the second sub-criterion cannot be regarded as being met. The lack of a significant change in load can rather be viewed as an indication of an undesired long-term regeneration. The method continues with blocks 107 and 112.

In blocks 107 and 112 it is checked, for example, whether certain regeneration stages are present. For example, in block 107 it is checked whether the (regeneration) method is currently in the third regeneration stage. In block 112 it is checked, for example, whether the (regeneration) method is currently in the fourth regeneration stage. In principle, however, regeneration stages other than the third and fourth or a total of more regeneration stages than the two examples given could also be tested here.

In block 108 or block 113 (depending on which of the two regeneration stages is present) a counter (belonging to the regeneration stage) is subsequently increased by a value. The counter usually counts driving cycles. In block 109 or block 114 it is checked whether the counter has reached or exceeded a predefined threshold value, such as at least three driving cycles. If the threshold value has not been reached, the method begins again, for example, with the next driving cycle at block 101. For example, it can be ensured that the missing significant load change determined in block 105 was not just a short-term condition, but with a high degree of probability a permanent one State is what can in particular allow a further conclusion about the presence of a permanent regeneration to be identified by means of the monitoring of the regeneration strategy.

If the counter in question has reached or exceeded the threshold value, an error can be suspected in block 110. This represents an example of the fact that and, if necessary, as in the case of a (repeated and / or successive) non-fulfillment of a sub-criterion of the test criterion within a regeneration stage, a suspicion of an error can be set. The relevant sub-criterion includes in particular the absence of a significant change in load (in regeneration stage three) over a certain minimum number of driving cycles.

Furthermore, an additional or more intensive regeneration measure can be triggered in block 110. Can do this For example, the method for monitoring specified here can cause a change to a higher regeneration level. In particular, this represents an external intervention in the (otherwise running independently) regeneration strategy or the (main) regeneration process by means of which the particle filter is regenerated.

This also gives an example that and, if necessary, as when changing to a higher regeneration level, an error is suspected. The in 1 For example, in block 110, a change (forced) would be made from regeneration level three to regeneration level four in block 110, although the loading level of the particle filter has not changed. For example, the regeneration level is (artificially) increased from three to four, although the loading level remains at three. Usually it can be provided that the regeneration stages according to the regeneration strategy or the (main) regeneration method are (directly) coupled to the current loading stage of the particle filter.

If the counter in question has reached or exceeded the threshold value, an error can be set in block 115 and output, for example. The error output can be made visible to the driver and, for example, prompt him to go to a workshop as quickly as possible. This also represents an example of how the suspected error set in block 110 can be confirmed and an error can be set if a further sub-criterion of the test criterion is not met within a regeneration stage (here, for example, regeneration stage four). The relevant further sub-criterion includes in particular the absence of a significant change in load (in regeneration stage four) over a certain minimum number of driving cycles (cf. block 114). In addition, a further change to a higher regeneration level (for example: regeneration level five or six) can take place in block 115. This usually requires maintenance of the particle filter in a workshop. The method can be ended or interrupted in each case with blocks 111 and 116 and, for example, restarted with the start of a new driving cycle at block 101.

2 shows schematically a flow chart to illustrate a further exemplary embodiment of the method described here. The method starts with block 200. In this exemplary embodiment, a first test criterion (right side of the flowchart) and a second test criterion (left side of the flowchart) can be tested at least partially in parallel. Alternatively, the second test criterion can also be tested here (in terms of time) before the first test criterion.

In block 201 it is checked whether certain prerequisites, such as sufficient activation energy and / or a sufficiently converted oxygen mass, are present. In block 202 it is checked with regard to the first test criterion whether a loading quotient of the loading of the particle filter has fallen or not. In this context, it can be checked, for example, whether the loading quotient has a sufficient, negative slope. For example, a measure for a change in pressure difference across the particle filter can be recorded as a measure for the loading quotient. A pressure difference sensor, for example, can be used for this purpose. If the loading quotient has fallen (sufficiently), there is no need to intervene in the regeneration strategy or an (artificially forced) change in the regeneration level is not necessary. In this context, the first test criterion can be run through again; a driving cycle counter assigned to the first test criterion can be reset in block 203.

If the loading quotient has not fallen, the method continues with block 204. In block 204, the driving cycle counter assigned to the first test criterion is increased. In block 205 it is then checked whether the counter in question has reached or exceeded a threshold value. If the counter in question has reached or exceeded the threshold value, it can be checked in block 206 whether regeneration stage four is already present. If regeneration level four is already present, a system error for the regeneration is set and output in block 207. If regeneration stage four is not present in block 206, a change is made in block 208 to a higher regeneration stage with more intensive regeneration measures compared to the previous regeneration stage. The counters assigned to the test criteria can then be reset and the method can be carried out again from block 200.

In block 209 it is checked whether certain prerequisites, such as an adequate exhaust gas mass flow and / or an adequate oxygen mass, have been implemented. In block 210, it is checked with regard to the second test criterion whether there is sufficient heating of the particle filter. In this context, for example, a measure for a temperature of the particle filter can be detected, in particular by sensors in the area of the particle filter. If the temperature (change) of the particulate filter is above a predetermined threshold value (for temperature rise evaluation), the process can continue with block 211. In block 211, a driving cycle counter assigned to the second test criterion is reset. The second test criterion can then be run through again.

If the heating of the particle filter is not sufficient, the process continues with block 212. In block 212, a heating cycle counter assigned to the second test criterion is increased, which in particular counts the heating attempts within a driving cycle. In block 213 it is then checked whether the counter in question has reached or exceeded a threshold value. If the counter in question has not yet reached or exceeded the threshold value, the second test criterion can be run through again. If the counter in question has reached or exceeded the threshold value, an error suspicion can be set in block 214. This also represents an example of the fact that and, if necessary, as if a partial criterion of the second test criterion is not met within a regeneration stage, an error can be suspected. A further driving cycle counter assigned to the second test criterion can then be increased in block 214. In block 215 it is then checked whether the relevant driving cycle counter has reached or exceeded a threshold value. If the driving cycle counter in question has not yet reached or exceeded the threshold value, the second test criterion can be run through again.

These different counters can help to split the second test criterion into two sub-criteria. In the first sub-criterion, it is consequently checked whether the heating of the particle filter (during a predeterminable number of (successive) heating cycles) within a driving cycle is not sufficient, which can lead to a suspicion of an error. In the second sub-criterion, it is checked whether the suspected fault is maintained during a predeterminable number of successive driving cycles, which can lead to a confirmation of the suspected fault and thus possibly to the setting of an error).

If the (second) counter in question has reached or exceeded the threshold value, a check can be made in block 216 to determine whether regeneration stage four is already present. If regeneration stage four is already present, a system error for the heating is set and output in block 217. If regeneration level four is not present in block 216, a change is made in block 208 to a higher regeneration level with regeneration measures that are more intensive than the previous regeneration level. The counters assigned to the test criteria can then be reset and the method can be carried out again from block 200. This also represents an example of how a suspected error is confirmed and an error is set if a further (second) sub-criterion of the second test criterion is not met within a regeneration stage.

3 shows schematically a (motor) vehicle 1 described here. The vehicle 1 has a gasoline engine 2 , on the gasoline engine 2 assigned exhaust system 3 and a system 4th for monitoring the regeneration of a particle filter 5 that is in the exhaust system 3 is arranged. The system 4th is set up to carry out a method described here for monitoring (the efficiency) of the regeneration of the particle filter.

Thus, a method for monitoring the regeneration of an Otto particle filter is specified which can at least partially solve the problems described in connection with the prior art. In particular, a method for monitoring the regeneration of an Otto particle filter can be specified, by means of which the efficiency of the regeneration, in particular the regeneration measures or the regeneration strategy of the Otto particle filter, can be monitored. In addition, a permanent regeneration by means of the method can advantageously be recognized and possibly even avoided.

List of reference symbols

1

vehicle

2

Gasoline engine

3

Exhaust system

4th

system

5

Particle filter

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 1170473 A1 [0004]
• US 8966882 B2 [0005]
• US 7536854 B2 [0006]

Claims (10)

A method for monitoring the regeneration of a particle filter which is arranged in an exhaust system of a gasoline engine, comprising at least the following steps: a) determining according to which regeneration stage of a defined number of regeneration stages the particle filter is being regenerated or was last regenerated; b) detecting a measure for at least one first test criterion which is characteristic of a change in the loading of the particle filter, c) Check whether the first test criterion is met, and change to a higher regeneration level if the first test criterion is not met, and change to a lower regeneration level or maintain the current regeneration level if the first test criterion is met. Procedure according to Claim 1 , the measure for the first test criterion being a measure of a change in pressure difference across the particle filter. Procedure according to Claim 1 or 2 , further comprising detecting a measure for a second test criterion which is characteristic of sufficient heating of the particle filter. Procedure according to Claim 3 , wherein the measure for the second test criterion is a measure for a temperature or a temperature change of the particle filter. Procedure according to Claim 3 or 4th , further comprising checking whether the second test criterion is met, and changing to a higher regeneration level if the second test criterion is not met, and changing to a lower regeneration level or maintaining the current regeneration level if the second test criterion is met. Method according to one of the preceding claims, wherein at least if a partial criterion of the test criterion is not fulfilled within a regeneration stage or if a change to a higher regeneration stage occurs, an error is suspected. Procedure according to Claim 6 , whereby the suspected error is confirmed and an error is set if a further sub-criterion of the test criterion is not met within a regeneration level or if the higher regeneration level is retained or switched to an even higher regeneration level in a subsequent test. Computer program for carrying out a method according to one of the preceding claims. Machine-readable storage medium on which the computer program is based Claim 8 is stored. Vehicle (1) with a gasoline engine (2), an exhaust system (3) assigned to the gasoline engine (2) and a system (4) for monitoring the regeneration of a particle filter (5) which is arranged in the exhaust system (3), according to a Method according to one of the Claims 1 until 7th .

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