DE102019202305A1 - Method for carrying out a vehicle diagnosis of a motor vehicle with an exhaust gas aftertreatment device - Google Patents

Abstract

The invention relates to a method for carrying out a vehicle diagnosis of a motor vehicle (2) with an exhaust gas aftertreatment device (4), comprising the steps:
(S100) reading in a data record (D1) representative of exhaust-gas emissions of the motor vehicle (2),
(S200) comparing the data set (D1) representative of exhaust-gas emissions of the motor vehicle (2) with a reference data set (RD),
(S300) reading in at least one further data record (D2) representative of operating parameters of the exhaust gas aftertreatment device (4), the at least further data record (D2) having data from a vehicle fleet to which the motor vehicle (2) belongs, representative of operating parameters of the exhaust gas aftertreatment device (4), if the data set (D1) is representative of exhaust-gas emissions from the motor vehicle (2) and violates the reference data set (RD), and
(S400) Evaluation of the data set (D1) representative of exhaust-gas emissions from the motor vehicle (2) and the at least further data set (D2) representative of operating parameters of the exhaust gas aftertreatment device (4).

Description

The invention relates to a method for carrying out a vehicle diagnosis of a motor vehicle with an exhaust gas aftertreatment device.

With exhaust gas aftertreatment devices, combustion gases are cleaned mechanically, catalytically or chemically after they have left the combustion chamber or the combustion chamber of an internal combustion engine driving the motor vehicle, in order to be able to comply with statutory pollutant limits.

To achieve strict emission conditions, exhaust gas aftertreatment devices have several different catalytic converters which can be arranged close to the engine and / or in the vehicle underbody, rather remote from the engine. To remove nitrogen oxides (NOx) from the exhaust gas flow, exhaust gas aftertreatment devices of this type have SCR catalytic converters and NOx storage catalytic converters, the NOx storage catalytic converter being arranged upstream of the SCR catalytic converter.

On-board diagnostic systems that detect a failure of a component of an exhaust gas aftertreatment device are, for example, from the EP 2 466 087 A1 , of the US 2012/210 700 A1 and the U.S. 6,857,262 known. From the EP 0 914 643 B1 it is known to evaluate data from an entire vehicle fleet.

However, such on-board diagnostic systems only record and evaluate the status of individual components of an exhaust gas aftertreatment device. A combined partial failure of several components could lead to the fact that each individual component is still assessed as functional, while the emissions lead to the motor vehicle being viewed as an "outlier" in a review of the emissions of a vehicle fleet to which the motor vehicle belongs. The presence of an "outlier" can mean that the regulations on which the emissions test for a vehicle fleet are based are deemed not to have been met.

There is therefore a need to show ways how this can be remedied.

• Einlesen eines Datensatzes repräsentativ für auspuffseitige Abgasemissionen des Kraftfahrzeugs,
• Vergleichen des Datensatzes repräsentativ für auspuffseitige Abgasemissionen des Kraftfahrzeugs mit einem Referenzdatensatz,
• Einlesen zumindest eines weiteren Datensatzes repräsentativ für Betriebsparameter der Abgasnachbehandlungseinrichtung, wobei der zumindest weitere Datensatz repräsentativ für Betriebsparameter der Abgasnachbehandlungseinrichtung Daten einer Fahrzeugflotte aufweist, zu der das Kraftfahrzeug gehört, wenn der Datensatz repräsentativ für auspuffseitige Abgasemissionen des Kraftfahrzeugs den Referenzdatensatz verletzt, und
• Auswerten des Datensatzes repräsentativ für auspuffseitige Abgasemissionen des Kraftfahrzeugs und des zumindest weiteren Datensatzes repräsentativ für Betriebsparameter der Abgasnachbehand lungseinrichtung.

The object of the invention is achieved by a method for carrying out a vehicle diagnosis of a motor vehicle with an exhaust gas aftertreatment device, with the steps:

• Reading in a data record representative of the exhaust gas emissions of the motor vehicle on the exhaust side,
• Comparing the data set representative of exhaust-gas emissions of the motor vehicle with a reference data set,
• Reading in at least one further data set representative of operating parameters of the exhaust gas aftertreatment device, the at least further data set having data of a vehicle fleet representative of the operating parameters of the exhaust gas aftertreatment device, to which the motor vehicle belongs, if the data set violates the reference data set representative of exhaust gas emissions of the motor vehicle, and
• Evaluation of the data set representative of exhaust-gas emissions of the motor vehicle and the at least further data set representative of operating parameters of the exhaust gas treatment device.

During a first phase of the method with the first two steps, it is determined by evaluating vehicle-specific data (data set representative of exhaust-gas emissions such as NOx) whether the present motor vehicle is an "outlier" of a vehicle fleet or not. If it is an “outlier”, data (data record representative of operating parameters of the exhaust gas aftertreatment device) relating to the vehicle fleet to which the present motor vehicle belongs are used in a second phase of the method. By using and evaluating the additional data, causes can be determined or limited which are the cause of the exhaust emissions. In this way, targeted measures can be initiated to reduce exhaust emissions in advance of a review of the emissions of a vehicle fleet.

According to one embodiment, the at least one further data set is representative of operating parameters of the exhaust gas aftertreatment device in the cold and / or warm and / or hot operating state. The cold operating state (light off) is understood to mean an operating state in which the exhaust gas aftertreatment device and / or its components have not yet reached their minimum operating temperature of, for example, 250 ° C. and thus insufficiently clean exhaust gas. The warm operating state is understood to mean an operating state in which the minimum operating temperature has been reached and the exhaust gas aftertreatment device converts, for example, NOx using SCR. The temperatures can be, for example, in a range from 250 ° C to 400 ° C. In contrast, the hot operating state is understood to mean an operating state in which the exhaust gas aftertreatment device and / or their components have reached a temperature which is above a threshold value which is above the minimum operating temperature, for example above 400 ° C. At these temperatures, for example, ammonia (NH ₃ ) is oxidized. By using the additional data set, the behavior of the exhaust gas aftertreatment device and / or its components can be analyzed at different operating temperatures.

According to a further embodiment, the at least one further data record is representative of operating parameters on the input side of the exhaust gas aftertreatment device. E.g. detects the NOx content of the exhaust gas flowing into the exhaust gas aftertreatment device or its components. This allows e.g. To exclude aging effects from the exhaust gas aftertreatment device and / or its components as causal, because such aging effects cause a shift in the onset characteristics during a warm-up phase.

According to a further embodiment, the data record representative of exhaust-gas emissions of the motor vehicle and / or the at least further data record representative of operating parameters of the exhaust gas aftertreatment device are a histogram. The respective data sets thus not only include data for a single operating point of the exhaust gas aftertreatment device and / or its components, but for a plurality of different operating points, and therefore allow exhaust emissions to be assigned to the respective operating points. It should be noted that the operating points can also be predetermined operating parameter ranges, e.g. Temperature ranges. An analysis of the behavior of the exhaust gas aftertreatment device and / or its components at different operating temperatures can thus be analyzed even more precisely.

The invention also includes a computer program product for a motor vehicle and a further computer program product, e.g. for a diagnostic device, such a diagnostic device and an onboard diagnostic device and a motor vehicle with such an onboard diagnostic device.

• 1 in schematischer Darstellung ein Szenario, bei dem eine Fahrzeugdiagnose eines Kraftfahrzeugs mit einer Abgasnachbehandlungseinrichtung durchgeführt wird.
• 2 in schematischer Darstellung einen Verfahrensablauf zum Durchführen der Fahrzeugdiagnose.
• 3 in schematischer Darstellung weitere Details des in 2 dargestellten Verfahrens.

The invention will now be explained with reference to a drawing. Show it:

• 1 a schematic representation of a scenario in which a vehicle diagnosis of a motor vehicle with an exhaust gas aftertreatment device is carried out.
• 2 a schematic representation of a method sequence for performing the vehicle diagnosis.
• 3 a schematic representation of further details of the in 2 presented procedure.

It gets on first 1 Referenced.

An internal combustion engine is shown 8th and an exhaust aftertreatment device 4th of a motor vehicle 2 , such as a car.

The internal combustion engine 8th is in the present embodiment a diesel engine. The diesel engine is operated in normal operation with an excess of oxygen (λ> 1) in lean operation. The internal combustion engine can deviate from this 8th can also be designed as a gasoline engine in lean operation to increase the engine efficiency.

The internal combustion engine 8th is turbo-charged in the present embodiment, so that in the exhaust gas flow of the internal combustion engine 8th a turbine 22nd an exhaust gas turbocharger is connected downstream, which drives a compressor (not shown).

Furthermore, there is the internal combustion engine 8th In the present exemplary embodiment designed for exhaust gas recirculation (EGR) and therefore has components of an exhaust gas recirculation 10 on, with an extraction of exhaust gas in front of the turbine 22nd the turbocharger and the exhaust aftertreatment 4th he follows.

The exhaust aftertreatment device 4th has in the present embodiment a DOC / NOx storage catalytic converter 12 and an SCR catalyst 14th on. In a departure from the present exemplary embodiment, the exhaust gas aftertreatment device 4th also have other catalysts with the same and / or different functions.

The DOC / NOx storage catalytic converter 12 is a combination of a diesel oxidation catalytic converter (DOC) and a NOx storage catalytic converter.

The diesel oxidation catalyst removes carbon monoxide (CO) and hydrocarbons (CmHn) from the exhaust gas of e.g. Diesel engines through oxidation with the residual oxygen.

The NOx storage catalytic converter is designed to store NOx (nitrogen oxides). It has a structure with a suitable carrier with a noble metal catalyst, such as platinum, and a NOx storage component, such as an alkaline earth metal such as barium. In normal operation when the internal combustion engine 8th is operated with a lean mixture, the DOC / NOx- Storage catalytic converter 12 NOx, while the stored NOx during regeneration phases of operation of the internal combustion engine 8th is released with a rich mixture and converted in the rich atmosphere. The change from the lean to the rich mixture and vice versa or the change between normal operation and regeneration operation is controlled by a control unit (not shown), which can have hardware and / or software components for this and the tasks and functions described below .

The SCR catalytic converter 14th is designed for the selective catalytic reduction of NOx with the addition of a urea-containing solution, such as AdBlue, which is injected into the exhaust gas flow at a urea injection point.

The car 2 furthermore has an onboard diagnostic device in the present exemplary embodiment 20th on. The onboard diagnostic device 20th is for on-board diagnosis (OBD) of the motor vehicle 2 educated. For this purpose, the onboard diagnostic device 20th While driving, all exhaust-influencing systems are monitored, as well as other important control units whose data are accessible. Any errors that occur are displayed to the driver via a control lamp and saved permanently. Error messages can then be reported later by a specialist workshop via standardized interfaces of the on-board diagnostic device 20th be queried. For this purpose and for the tasks and / or functions described below, the onboard diagnostic device 20th Have hardware and / or software components.

In the present exemplary embodiment, the onboard diagnostic device reads 20th Measured values obtained with a first NOx sensor 16a input side of the SCR catalytic converter 14th and a second NOx sensor 16b on the output side of the SCR catalytic converter 14th are recorded.

The one with the first NOx sensor 16a The measured values recorded are therefore representative of the exhaust gas emissions of the motor vehicle 2 , while the one with the second NOx sensor 16b recorded measured values representative of the operating parameters of the exhaust gas aftertreatment device 4th , so here the composition of the exhaust gas that the SCR catalytic converter 14th is fed.

The onboard diagnostic device 20th is designed in the present exemplary embodiment to that with the first NOx sensor 16a recorded measured values for further data, such as temperature values of the exhaust gas aftertreatment device 4th and / or its components, assign to the first record D1 in the form of a histogram. There is also the onboard diagnostic device 20th in the present exemplary embodiment designed to do so, analogously to that with the second NOx sensor 16b recorded measured values for further data, such as temperature values of the exhaust gas aftertreatment device 4th and / or its components, assign to the second data set D2 in the form of a histogram.

Both the first record D1 as well as the second record D2 are in the present embodiment in a cloud 18th other, corresponding data records from other motor vehicles of the vehicle fleet to which the motor vehicle 2 heard.

It will now be made with additional reference to FIG 2 a method for carrying out a vehicle diagnosis of the motor vehicle 2 with the help of a diagnostic device 6th explained. The diagnostic device differs here 6th from the onboard diagnostic device 20th by having the onboard diagnostic device 20th an integral part of the motor vehicle 2 is while the diagnostic device 6th only temporarily - and then only transferring data - with the motor vehicle 2 connected is. It should be noted that the diagnostic device 6th can also be designed as an online tool, i.e. as a software application.

In a first step S100 reads the diagnostic device 6th the first record D1 representative of the exhaust gas emissions of the motor vehicle on the exhaust side 2 a.

In a further step S200 compares the diagnostic device 6th the first record D1 representative of the exhaust gas emissions of the motor vehicle on the exhaust side 2 with a reference data record RD. In the present exemplary embodiment, the reference data record RD contains a plurality of limit values for permissible exhaust gas emissions for various operating points.

It should be noted that to perform the two steps S100 and S200 only data relating to the present motor vehicle are used during a first phase of the method 2 affect.

The procedure only involves one more step S300 continued when the diagnostic tool 6th finds that the record D1 representative of the exhaust gas emissions of the motor vehicle on the exhaust side 2 violates the reference data record RD.

Notwithstanding the present exemplary embodiment, it can also be provided that the two steps S100 and S200 not in the diagnostic device, but in the onboard diagnostic device 20th are executed. In this case, for example, the onboard diagnostic device 20th a logical variable the value assigned to logical one if the record D1 representative of the exhaust gas emissions of the motor vehicle on the exhaust side 2 violates the reference data record RD. Otherwise the logical variable has the value logical zero.

If the logical variable with the value logical one is present, the diagnostic device then sets the procedure with the step S300 away.

The comparison with the reference data set RD was used to determine whether the motor vehicle 2 is an "outlier" or not. The procedure continues with the next step S300 continued when the present motor vehicle 2 is an "outlier".

With the next step S300 A second phase of the method now begins, in which data from a vehicle fleet for which the motor vehicle is used is also used 2 heard.

In the next step S300 reads the diagnostic device 6th at least one more, e.g. in the cloud 18th saved data set D2 representative of the operating parameters of the exhaust gas aftertreatment device 4th one, the at least further data set D2 representative of the operating parameters of the exhaust gas aftertreatment device 4th Has data of a vehicle fleet to which the motor vehicle 2 heard.

In the present exemplary embodiment, the diagnostic device reads 6th a plurality of records D2 representative of the operating parameters of the exhaust gas aftertreatment device 4th a.

For example, there are further data records D2 read in, which is representative of the operating parameters of the exhaust gas aftertreatment device 4th are in cold, warm and hot operating status.

There are also other records D2 read in, which is representative of operating parameters on the input side of the exhaust gas aftertreatment device 4th , in the present exemplary embodiment on the input side of the SCR catalytic converter 14th , are.

In a further step S400 evaluates the diagnostic device 6th the first record D1 representative of the exhaust gas emissions of the motor vehicle on the exhaust side 2 and at least one more data set D2 representative of the operating parameters of the exhaust gas aftertreatment device 4th out. For this purpose is additionally on 3 Referenced.

In 3 are exemplary data sets D2 shown in histogram form. If the readings of the motor vehicle 2 left of the border G located meets the motor vehicle 2 the predetermined emission limits. If, however, the values of the motor vehicle 2 right of the border G located meets the motor vehicle 2 the predetermined emission limits do not.

The border G can be based on predetermined limit values, or a value for the limit G is made by evaluating one of the data sets D1 or D2 determined, for example in the sense that for the worst 5% of a vehicle fleet a malfunction of the exhaust gas aftertreatment device 4th Is accepted.

If, for example, the input side with the first NOx sensor 16a detected NOx values the respective limit G violate the output side with the second NOx sensor 16b detected NOx values the respective limit G but not, it can be concluded that either the SCR catalytic converter 14th or that of the SCR catalytic converter 14th associated urea injection system 24 needs to be serviced.

Another distinction between SCR catalytic converters 14th the or that the SCR catalytic converter 14th associated urea injection system 24 can now be carried out at the vehicle level by means of a controlled urea overdosage test, which takes advantage of the fact that NOx sensors such as the second NOx sensor on the exhaust side 16b is sensitive to both NOx and NH ₃ . Thus, for example, a sudden increase in the urea fed in should occur with the second NOx sensor 16b be detected, so that a malfunction of the urea injection system 24 can be excluded.

In a departure from the present exemplary embodiment, the sequence of the steps can also be different. Furthermore, several steps can also be carried out at the same time or simultaneously.

In the present exemplary embodiment, a vehicle diagnosis of a motor vehicle is carried out 2 with an exhaust aftertreatment device 4th with a DOC / NOx storage catalytic converter 12 and an SCR catalytic converter 14th explained. However, the method can also be used in the context of a vehicle diagnosis for other components of the exhaust gas aftertreatment device 4th and / or the motor vehicle 2 can be used analogously, such as the DOC / NOx storage catalytic converter 12 and / or exhaust gas recirculation ( 10 ).

In this way, targeted, statistically supported measures can be initiated in order to reduce the exhaust emissions in advance of a review of the emissions of a vehicle fleet.

List of reference symbols

2

Motor vehicle

4th

Exhaust aftertreatment device

6th

Diagnostic device

8th

Internal combustion engine

10

Exhaust gas recirculation

12

DOC / NOx storage catalytic converter

14th

SCR catalytic converter

16a

NOx sensor

16b

NOx sensor

18th

Cloud

20th

Onboard diagnostic device

22nd

turbine

24

Urea injection system

D1

record

D2

record

G

border

RD

Reference data set

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 2466087 A1 [0004]
• US 2012/210700 A1 [0004]
• US 6857262 [0004]
• EP 0914643 B1 [0004]

Claims (13)

Method for performing a vehicle diagnosis of a motor vehicle (2) with an exhaust gas aftertreatment device (4), comprising the steps: (S100) reading in a data record (D1) representative of exhaust-gas emissions of the motor vehicle (2), (S200) comparing the data set (D1) representative of exhaust-gas emissions of the motor vehicle (2) with a reference data set (RD), (S300) reading in at least one further data record (D2) representative of operating parameters of the exhaust gas aftertreatment device (4), the at least further data record (D2) having data from a vehicle fleet to which the motor vehicle (2) belongs, representative of operating parameters of the exhaust gas aftertreatment device (4), if the data set (D1) is representative of exhaust-gas emissions from the motor vehicle (2) and violates the reference data set (RD), and (S400) Evaluation of the data record (D1) representative of exhaust-gas emissions of the motor vehicle (2) on the exhaust side and the at least further data record (D2) representative of operating parameters of the exhaust gas aftertreatment device (4). Procedure according to Claim 1 , wherein the at least one further data record (D2) is representative of operating parameters of the exhaust gas aftertreatment device (4) in the cold and / or warm and / or hot operating state. Procedure according to Claim 1 or 2 , wherein the at least one further data set (D2) is representative of operating parameters on the input side of the exhaust gas aftertreatment device (4). Procedure according to Claim 1 , 2 or 3 , the data set (D1) being representative of exhaust-gas emissions of the motor vehicle (2) and / or the at least further data set (D2) being a histogram representative of operating parameters of the exhaust gas aftertreatment device (4). Computer program product for a motor vehicle (2), designed to carry out a method at least according to Claim 1 . Computer program product designed to carry out a method according to one of the Claims 1 to 4th . Diagnostic device (6) for carrying out a vehicle diagnosis of a motor vehicle (2) with an exhaust gas aftertreatment device (4), the diagnostic device (6) being designed to read in at least one further data set (D2) representative of operating parameters of the exhaust gas aftertreatment device (4), the at least further data set (D2) representative of operating parameters of the exhaust gas aftertreatment device (4) has data of a vehicle fleet to which the motor vehicle (2) belongs when a data set (D1) representative of the exhaust gas emissions of the motor vehicle (2) violates a reference data set (RD) and the To evaluate data set (D1) representative of exhaust-gas emissions of the motor vehicle (2) and the at least further data set (D2) representative of operating parameters of the exhaust gas aftertreatment device (4). Diagnostic device (6) Claim 7 , the diagnostic device (6) being designed to read in the data set (D1) representative of exhaust-gas emissions of the motor vehicle (2) and to compare it with the reference data set (RD). Diagnostic device (6) Claim 7 or 8th , wherein the at least one further data record (D2) is representative of operating parameters of the exhaust gas aftertreatment device (4) in the cold and / or warm and / or hot operating state. Diagnostic device (6) Claim 7 , 8th or 9 , wherein the at least one further data set (d2) is representative of operating parameters on the input side of the exhaust gas aftertreatment device (4). Diagnostic device (6) after one of the Claims 7 to 10 , the data set (D1) being a histogram representative of the exhaust gas emissions of the motor vehicle (2) and / or the at least further data set (D2) being representative of the operating parameters of the exhaust gas aftertreatment device (4). Onboard diagnostic device (20) for a motor vehicle (2), the onboard diagnostic device (20) being designed to read in a data record (D1) representative of exhaust-gas emissions of the motor vehicle (2) and to read the data record (D1) representative of exhaust-gas emissions of the Compare motor vehicle (2) with a reference data set (RD). Motor vehicle (2) with an onboard diagnostic device (10) Claim 12 .

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