DE102019008967A1 - Method for operating an exhaust gas aftertreatment device of a motor vehicle, in particular a motor vehicle - Google Patents

Abstract

The invention relates to a method for operating an exhaust gas aftertreatment device of a motor vehicle through which exhaust gas from an internal combustion engine can flow and which has at least one nitrogen oxide storage catalytic converter, a future period of time during which a fired operation of the internal combustion engine will not occur depending on at least one route of the motor vehicle ahead of the motor vehicle is, with a regeneration of the nitrogen oxide storage catalytic converter being carried out at least during part of the period of time as a function of the predicted time period.

Description

The invention relates to a method for operating an exhaust gas aftertreatment device of a motor vehicle, in particular a motor vehicle, according to the preamble of claim 1.

Such methods for operating exhaust gas aftertreatment devices of motor vehicles are already sufficiently known from the general prior art. Exhaust gas from an internal combustion engine of the motor vehicle can flow through the exhaust gas aftertreatment device and has at least one nitrogen oxide storage catalytic converter in or by means of which any nitrogen oxides contained in the exhaust gas can be stored. Furthermore, the EP 2 460 994 A2 an exhaust system having an exhaust pipe through which exhaust gas flows.

The object of the present invention is to further develop a method of the type mentioned at the beginning in such a way that particularly low-emission operation can be implemented.

This object is achieved by a method with the features of claim 1. Advantageous configurations with expedient developments of the invention are specified in the remaining claims.

In order to further develop a method of the type specified in the preamble of claim 1 in such a way that particularly low-emission operation can be implemented, it is provided according to the invention that, in particular by means of an electronic computing device, in particular of a motor vehicle, depending on at least one of the vehicle ahead and, for example In the near future the route of the motor vehicle to be traveled by the motor vehicle, a future period of time is predicted, during which period there is no fired operation of the internal combustion engine, in particular continuously or without interruption. This means that no combustion processes take place in the internal combustion engine during the, in particular the entire, period of time, which is also referred to as duration or duration. The feature that the period of time is a future period of time can in particular be understood to mean that, for example, the period of time is determined at a first point in time or during a time interval and is thus predicted, that is, is predicted, the period of time starting at the first point in time or at the time interval follows. Expressed again in other words, the time span with respect to the first point in time or with respect to the time interval lies in the future. For example, the time span is estimated. This means that the time span does not necessarily have to occur, but the time span will occur with a certain probability in the future.

In the method, a regeneration, also referred to as denoxation, of the nitrogen oxide storage catalytic converter, also referred to simply as a storage catalytic converter, is carried out at least during part of the period of time and thus during a fired operation of the internal combustion engine. Regeneration of the storage catalytic converter is to be understood as meaning that nitrogen oxides (NOx) stored in the storage catalytic converter are at least partially removed from the storage catalytic converter, that is to say are stored out. For this purpose, the storage catalytic converter is heated, for example. The method is carried out, for example, while the motor vehicle is traveling, wherein the time span can be at least part of the journey, for example. During the period of time, the motor vehicle, for example designed as a hybrid vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car, is driven purely electrically by means of an electrical machine, while the internal combustion engine is deactivated and, for example, is at a standstill, i.e. no combustion processes in the internal combustion engine occur .

For example, an end time is also forecast, in particular by means of the electronic computing device, the time span ending at the end time. In this case, regeneration of the nitrogen oxide storage catalytic converter is carried out at least during part of the time period, also as a function of the predicted end time. At the end point in time, the internal combustion engine, which was initially deactivated during the period of time, is activated, that is to say switched to its fired operation. The activation of the internal combustion engine is also referred to as starting the engine, starting, restarting or restarting the internal combustion engine. Overall, it can be seen that the period of time ends when the internal combustion engine is restarted. The method can ensure that from the end time, i.e. from the start of the fired operation of the internal combustion engine and thus from the end of the period of time, the nitrogen oxide storage catalytic converter has a sufficiently high storage capacity for storing nitrogen oxides from the exhaust gas, so that a low-emission Operation can be guaranteed. This sufficiently high storage capacity of the storage catalytic converter is set or implemented while the internal combustion engine is deactivated and especially while the motor vehicle is driven purely electrically, for example.

The route ahead of the motor vehicle is determined for example by means of a navigation device, in particular on the basis of a route planned for example by means of a navigation device, in particular a motor vehicle, and for example as a function of a current position of the motor vehicle on the earth, the current position being determined for example by means of a navigation device . For example, forecast data or route information are generated by means of the electronic computing device, which characterize the route ahead. The route information is information about the route ahead, this information being generated, for example, for an engine control device for controlling and / or regulating the internal combustion engine. The engine control unit, which is an electronic computing device, for example, can use the route information to regenerate the storage catalytic converter as a function of the predicted time span and preferably also as a function of the predicted end time, in particular not taking place during combustion processes in the internal combustion engine and preferably during the motor vehicle, in particular pure, electrically powered.

Preferably, in particular by means of the electronic computing device, a power to be provided by the internal combustion engine at the end and thus for example at the end time of the period of time and also referred to as power output is predicted, with the regeneration of the nitrogen oxide storage catalytic converter at least during part of the time period also being dependent is carried out by the forecast performance or output. The power is a power output of the internal combustion engine when it is restarted. By taking into account the time span and preferably also the end time and / or the power output, the storage catalytic converter can be particularly advantageously regenerated so that it can particularly advantageously absorb nitrogen oxides from the exhaust gas of the internal combustion engine and thus store it from the end time and thus from the fired operation of the internal combustion engine. The method according to the invention is an intelligent control or regulation, by means of which the denoxification of the nitrogen oxide storage catalytic converter can be put in a targeted manner in those phases in which the internal combustion engine is deactivated.

To regenerate the nitrogen oxide storage catalytic converter, at least during part of the period, a fuel-air mixture is burned, for example, by means of a burner which is different from the internal combustion engine and which can preferably be operated independently of the internal combustion engine, whereby the nitrogen oxide storage catalytic converter is heated and thereby regenerated . Alternatively or additionally, for example, at least during part of the period of time, the nitrogen oxide storage catalytic converter is heated and thereby regenerated by means of a catalytic burner which is provided in addition to the internal combustion engine and is different from the internal combustion engine. As a result, the nitrogen oxide storage catalytic converter (NOx storage catalytic converter) can be denoxed completely independently of the internal combustion engine and in particular take place when the internal combustion engine is deactivated.

For example, for the regeneration of the nitrogen oxide storage catalytic converter, at least during part of the period of time, a device that is different from the internal combustion engine, is additionally provided and can be operated independently of the internal combustion engine, in particular electrically, generates a gas flow, for example designed as an air flow or at least or exclusively comprising air, which at least flows through the nitrogen oxide storage catalytic converter. For example, the respective burner and / or the device is operated independently of the internal combustion engine, in particular, while the internal combustion engine is deactivated. For example, the gas flow is heated by means of the respective burner, so that the nitrogen oxide storage catalytic converter is heated by means of the gas flow and thus regenerated. As a result, the storage catalytic converter can be completely self-sufficient to be denoxed by the internal combustion engine while the internal combustion engine is deactivated.

• - Gewährleistung eines vorteilhaften Betriebs der auch als Abgasreinigungssystem bezeichneten Abgasnachbehandlungseinrichtung
• - Reduzierung des Kraftstoffverbrauchs und der Emissionen gegenüber herkömmlichen Lösungen
• - brennverfahrensunabhängige Nutzung, so dass das Verfahren auch bei einem Ottomotor genutzt werden kann
• - Regeneration beziehungsweise Reinigung des auch als NSK oder NOx-Speicherkat bezeichneten Stickoxid-Speicherkatalysators
• - Entfall von verbrennungsmotorischen Brennverfahren zur Denoxierung des Speicherkatalysators

In particular, the invention can achieve the following advantages:

• - Ensuring an advantageous operation of the exhaust gas aftertreatment device, also referred to as an exhaust gas cleaning system
• - Reduction of fuel consumption and emissions compared to conventional solutions
• - Use independent of the combustion process, so that the process can also be used with a gasoline engine
• - Regeneration or cleaning of the nitrogen oxide storage catalytic converter, also known as NSK or NOx storage catalytic converter
• - No need for internal combustion engine combustion processes for denoxing the storage catalytic converter

Further advantages, features and details of the invention emerge from the following description of preferred exemplary embodiments and on the basis of the drawing. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination, but also in other combinations or alone, without the scope of the Invention to leave.

• 1 ein Flussdiagramm zum Veranschaulichen eines erfindungsgemäßen Verfahrens zum Betreiben einer Abgasnachbehandlungseinrichtung eines Kraftfahrzeugs;
• 2 ein weiteres Flussdiagramm zum weiteren Veranschaulichen des Verfahrens; und
• 3 ein weiteres Flussdiagramm zum weiteren Veranschaulichen des Verfahrens.

The drawing shows in:

• 1 a flowchart to illustrate a method according to the invention for operating an exhaust gas aftertreatment device of a motor vehicle;
• 2 a further flow chart to further illustrate the method; and
• 3 a further flow chart to further illustrate the method.

In the following, using 1 to 3 a method for operating an exhaust gas aftertreatment device of a motor vehicle is described. The motor vehicle, which is preferably designed as a motor vehicle, in particular as a passenger vehicle, has, in its fully manufactured state, the exhaust gas aftertreatment device and an internal combustion engine by means of which the motor vehicle can be driven. The internal combustion engine can, in particular in its fired operation, provide an exhaust gas which can flow through the exhaust gas aftertreatment device. The exhaust gas aftertreatment device is designed to aftertreat the exhaust gas. For this purpose, the exhaust gas aftertreatment device comprises at least one nitrogen oxide storage catalyst, also referred to simply as a storage catalyst, in or by means of which nitrogen oxides can be absorbed from the exhaust gas and at least temporarily stored. As the amount of nitrogen oxides stored in the nitrogen oxide storage catalytic converter increases, so-called loading of the nitrogen oxide storage catalytic converter increases. In other words, the amount of nitrogen oxides stored in the nitrogen oxide storage catalytic converter is also referred to as the loading or nitrogen oxide loading of the storage catalytic converter.

In the method, an electronic computing device, in particular a motor vehicle, is used to determine a route of the motor vehicle which is ahead of the motor vehicle and thus which the motor vehicle will travel on with a certain probability in the near future. Depending on the determined route of the motor vehicle ahead of the motor vehicle, the electronic computing device is used to forecast, that is, predict a future period of time, with the internal combustion engine not operating during the period of time. The period of time is, for example, at least part of an electric trip of the motor vehicle, which is driven purely electrically during the electric trip. The motor vehicle is, for example, a hybrid vehicle which has at least one electrical machine by means of which the motor vehicle can be driven electrically, in particular purely. While the motor vehicle is driven purely electrically by means of the electric machine, the internal combustion engine is deactivated, so that the internal combustion engine does not operate in a fired manner. Depending on the predicted time span, the nitrogen oxide storage catalytic converter is regenerated at least during part of the time span and thus at least during part of the electric drive of the motor vehicle. The regeneration of the nitrogen oxide storage catalytic converter is to be understood as meaning that at least some of the nitrogen oxides initially stored in the storage catalytic converter are removed from the storage catalytic converter, that is to say stored out. For this purpose, the storage catalytic converter is heated, for example.

With an in 1 shown block 10 For example, the current loading of the storage catalytic converter is determined, in particular via a storage model and / or via evaluation of at least one or more nitrogen oxide sensors, by means of which nitrogen oxides, in particular contained in the exhaust gas, can be measured. In a block 12, information about the future route or several future routes is evaluated. The information thus characterizes the route ahead of the motor vehicle. With a block 14th it is determined how long the next, predicted electric journey of the motor vehicle will last. Thus, the block 14th predicts the aforementioned period of time during which the internal combustion engine, in particular continuously or without interruption, is deactivated and, for example, the motor vehicle is driven purely electrically and is thus driven.

With a block 16 it is checked whether the time span is sufficient to carry out a sufficient regeneration, also referred to as denoxification, of the nitrogen oxide storage catalytic converter within the time span, that is to say at least during part of the time span. If the time span is too short, for example, to be able to regenerate the storage catalytic converter sufficiently, the method ends, for example, at the block 18th where nothing is done. However, if the period of time is long enough for the storage catalytic converter To be able to adequately denoxify is the case with a block 20th the regeneration of the storage catalyst carried out, in particular at least during part of the electric trip.

For example, to regenerate the storage catalytic converter, the storage catalytic converter is heated by means of a heating element, in particular by means of a catalytic burner, at least during part of the period of time. Alternatively or additionally, a burner is used to regenerate the storage catalytic converter, which burns a fuel-air mixture, whereby the storage catalytic converter is heated. By means of a device which is different from the internal combustion engine, is additionally provided and can be operated independently of the internal combustion engine, a gas flow is generated, for example, in particular by operating the device independently of the internal combustion engine while the internal combustion engine is deactivated. Thus, for example, the device is operated at least during part of the time period. The gas stream flows at least through the storage catalytic converter and is heated, for example, by means of the aforementioned burner, so that the storage catalytic converter is heated by means of the gas flow and subsequently regenerated. As a result, the storage catalytic converter can be regenerated during the electric journey and independently or completely self-sufficient from the internal combustion engine.

If the time span then ends at an end time at which the internal combustion engine is activated, the storage catalytic converter can particularly advantageously store nitrogen oxides from the exhaust gas from the end time, so that particularly low-emission operation can be implemented. It is preferably provided that the end time is also predicted by means of the electronic computing device as a function of the driving route ahead. Furthermore, a power to be provided by the internal combustion engine at the end time and also referred to as power output is predicted, for example, by means of the electronic computing device, the regeneration of the storage catalytic converter preferably also being carried out as a function of the predicted power output.

2 shows a further flowchart, on the basis of which a generation of forecast data for the use of information about the route is described below. In 2 illustrates a block 22nd Navi data, that is to say navigation data, which are provided, for example, by a navigation device. The navigation data includes, for example, GPS data (GPS - Global Positioning System) and / or ADAS data. The navigation data includes, for example, information about a possible city, a terrain topology, a speed and / or a destination. A block 24 illustrates, for example, a central drive train control unit for operating, in particular regulating or controlling, a drive train of the motor vehicle, the central drive train control unit also being referred to as a central powertrain controller (CPC). By the block 24 For example, signal processing takes place, in the context of which the navigation data is converted into performance data. A block 26th illustrates, for example, the aforementioned engine control unit, which uses the predictive performance data. A block 28 illustrates a use of the performance data. For example, in the case of the block 28 an estimate of how long the internal combustion engine can remain deactivated in its unfired operation or when the internal combustion engine must be reactivated, for example in order to drive the motor vehicle or to support the electrical machine in driving the motor vehicle. Also takes place at the block 28 for example, a time forecast as to when the internal combustion engine must be reactivated. In addition, for example, occurs at the block 28 a prediction of the power output with which the internal combustion engine must start again.

3 shows a further flow chart to further illustrate the method. A block 30th illustrates, for example, ADAS or GPS and / or a navigation device, which - as by a case 32 is illustrated - provides predictive route data in an electronic horizon. With a block 34 a signal processing takes place, which - as indicated by an arrow 36 illustrates - provides input attributes. In the case of a slope detection, the input attributes characterize at least one or more slopes, for example. In the case of city recognition, the input attributes characterize, for example, a city and / or at least one or more speed limits. In the case of target recognition, the input attributes characterize, for example, at least part of a calculated route which the motor vehicle is to travel on or is being traveled on. A block 38 illustrates a recognition algorithm which, for example, carries out an incline recognition, a city recognition and / or a target recognition. The block 28 provides output attributes, which are indicated by an arrow 40 are illustrated. The output attributes characterize at least one slope attribute, at least one city attribute and / or at least one destination attribute, for example. Finally, a block illustrates 42 an activation, in particular a regulation or control, whereby the drive train and thus the Internal combustion engine and / or the regeneration operated, in particular controlled or regulated, is. An algorithm for slope detection receives as input variables, for example, a minimum for a positive gradient, a maximum for a negative gradient and the at least one slope. Outputs of the algorithm are, for example, a start of the slope, an end of the slope, a vector length as a control, a distance to the slope and a slope length. The algorithm for city recognition receives as input variables, for example, at least one speed limit, at least one value that characterizes a built-up area and / or navigation data that can characterize a current position of the motor vehicle. As outputs, the algorithm for city recognition provides, for example, a beginning of a city, an end of a city, a vector length as a control, a distance to the beginning of the city and / or a city length. The algorithm for target recognition receives, for example, a position of the motor vehicle along the calculated route and the current position of the motor vehicle as input variables. The target detection algorithm provides, for example, a vector length as a control and a distance to the target as the output variable. As a result, the route ahead can be determined particularly precisely, so that the time span can be predicted particularly precisely. As a result, the regeneration of the nitrogen oxide storage catalytic converter can advantageously be carried out at least during part of the period of time, so that when the internal combustion engine is restarted, nitrogen oxides can be particularly advantageously stored from the exhaust gas again by means of the nitrogen oxide storage catalytic converter. In this way, a particularly low-emission and energy-efficient operation of the motor vehicle can be guaranteed.

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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 2460994 A2 [0002]

Claims (7)

Method for operating an exhaust gas aftertreatment device of a motor vehicle through which exhaust gas from an internal combustion engine can flow and which has at least one nitrogen oxide storage catalyst, characterized in that, depending on at least one route of the motor vehicle ahead of the motor vehicle, a future period of time during which fired operation of the internal combustion engine will not take place is forecast , wherein a regeneration of the nitrogen oxide storage catalytic converter is carried out at least during part of the time period as a function of the predicted time period. Procedure according to Claim 1 , characterized in that an end time at which the time span ends is also forecast, the regeneration of the nitrogen oxide storage catalytic converter being carried out at least during part of the time span as a function of the predicted end time. Procedure according to Claim 1 or 2 , characterized in that a power to be provided by the internal combustion engine at one end of the time period is also predicted, the regeneration of the nitrogen oxide storage catalytic converter being carried out at least during part of the time period as a function of the predicted power. Method according to one of the preceding claims, characterized in that for the regeneration of the nitrogen oxide storage catalytic converter, at least during part of the period of time, a fuel-air mixture is burned by means of a burner that is different from the internal combustion engine and additionally provided, whereby the nitrogen oxide storage catalytic converter is heated and is thereby regenerated. Method according to one of the preceding claims, characterized in that at least during part of the period of time the nitrogen oxide storage catalytic converter is heated by means of a catalytic burner and thereby regenerated. Method according to one of the preceding claims, characterized in that for the regeneration of the nitrogen oxide storage catalytic converter, at least during part of the period of time, a gas flow is generated by means of a device which is different from the internal combustion engine, is additionally provided and can be operated independently of the internal combustion engine, in particular electrically flows through at least the nitrogen oxide storage catalytic converter. Procedure according to Claim 6 in its reference to Claim 4 or 5 , characterized in that the gas stream is heated by means of the burner.

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