Method for determining a malfunction of a line for carrying a carrier mass flow

Abstract

Method for determining a malfunction of a line (6) for guiding a carrier mass flow of an exhaust system (4) of an internal combustion engine (18) which can be heated by means of a heating element (12), comprising the steps: - Activating a heating element (12) to heat the exhaust aftertreatment component (8), - Heating the exhaust aftertreatment component (8) via the radiant heat of the heating element (12), - Recording (100) a current actual temperature profile (T Ist ) on the line (6) by means of a temperature sensor (10), - Comparing (200) the recorded actual temperature profile (T Ist ) with a predefined reference temperature profile (T Ref ), - Creating (300) a diagnosis regarding the functionality of the line (6) based on the comparison of the recorded actual temperature profile (T Ist ) with the predefined reference temperature profile (T Ref ), where, based on the diagnosis made regarding the functionality of the line (6) for guiding a carrier mass flow, a risk of overheating of the heating element (12) is assessed, and Further measures will be initiated based on the assessment.

Description

[0001] The present invention relates to a method and a system for detecting a malfunction of a line for guiding a carrier mass flow and to a vehicle comprising such a system.

[0002] To minimize exhaust emissions, the exhaust system of combustion engine vehicles can be heated, for example, by means of an electrically operated heating element. To heat the exhaust system, the heating element is supplied with a carrier mass flow directed towards a catalytic converter downstream of the element, thus heating it. This heating can take place both before starting the engine and while the engine is running. The carrier mass flow can be supplied via various means, such as secondary air pumps or electrically operated exhaust gas turbochargers.

[0003] However, if there is no or insufficient carrier mass flow, the problem arises that the heating disc can overheat and be damaged. Impairment of the carrier mass flow can be caused, for example, by leaks (e.g., through pipe breaks), stuck valves in pipe sections, or coking or blockage of the pipes. Furthermore, a conventional secondary air system diagnostic is usually only performed after a secondary air phase. Depending on the current requirements, a subsequent diagnostic check may already be too late to prevent damage to the heating disc from overheating if the carrier mass flow is impaired.

[0004] Systems and methods for detecting a malfunction in a carrier mass flow line are known from the prior art, e.g., DE 10 2004 053 955 A1, DE 10 2017 115 408 A1, US 5 060 474 A, JP H03 15 619 A, and the publication by van Basshuysen, Schäfer (eds.): Handbuch Prozessionsmotoren [Handbook of Internal Combustion Engines]. 7th edition. Springer Vieweg: Wiesbaden, 2015. pp. 838, 839. However, the systems and methods known from the prior art are generally too imprecise to reliably detect and evaluate a malfunction in a carrier mass flow line. In particular, the known systems and methods lack consideration of the heating of carrier mass flow lines by heating elements used to heat exhaust aftertreatment components. DE 10 2004 001 330 A1 discloses a method for diagnosing a secondary air system of an internal combustion engine.Here, a measure of secondary air is determined and evaluated based on the thermal behavior within the thermoreactor. This measure is derived from the evaluation of the temperature profile over time. Furthermore, the secondary air measure is compared to a temperature threshold, and a diagnostic signal is provided based on the comparison result. US Patent 5,412,943 A discloses a secondary air supply device comprising a pump, a control valve, a heater, and a control unit for these components. The secondary air supply device also includes an air supply pipe through which it is connected to the exhaust pipe to introduce secondary air.

[0005] It is therefore the object of the present invention to at least partially overcome the disadvantages described above. In particular, it is the object of the present invention to propose a method or system that guarantees, in a structurally simple and cost-effective manner, a fast and reliable detection of a malfunction in a line for carrying a mass flow.

[0006] The foregoing problem is solved by a method with the features of claim 1, a system with the features of claim 6, and a vehicle with the features of claim 9. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the system and the vehicle according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes, or can make, reciprocal references.

[0007] According to the invention, a method is provided for determining a malfunction of a line for carrying a carrier mass flow of an exhaust system of an internal combustion engine that is heated by means of a heating element. The method according to the invention comprises the steps of acquiring a current actual temperature profile on the line using a temperature sensor, comparing the acquired actual temperature profile with a predefined reference temperature profile, and generating a diagnosis with regard to the functionality of the line based on the comparison of the acquired actual temperature profile with the predefined reference temperature profile.

[0008] According to the invention, the present method is designed to enable the rapid and reliable detection of a malfunction in a line for carrying a carrier mass flow, thereby effectively and reliably preventing damage caused by overheating of a heating disc, through the sequence of process steps provided according to the invention. The process steps according to the invention can preferably be carried out in the specified sequence. However, it is also possible to deviate from the specified sequence. In particular, when carrying out the method according to the invention, individual or all steps of the method can be repeated, e.g., cyclically one after the other. In contrast to known methods for detecting a malfunction in a line for carrying a carrier mass flow, here the current temperature profile is compared with a predefined reference temperature profile.In this way, random deviations that could lead to misdiagnoses can be reliably eliminated. A carrier mass flow can preferably be understood as the mass flow conveyed through the exhaust system, in particular the secondary air mass flow, which can be supplied via secondary air lines from a secondary air source. Within the scope of the invention, a malfunction of a line for conveying a carrier mass flow can be understood in particular as the presence of a line leak or blockage, or the like, which results in the line no longer being able to function, namely, to convey a carrier mass flow largely unimpeded. In the context of a diagnosis regarding functionality, a distinction can be made, for example, between different degrees of impairment of the functionality of a line for conveying a carrier mass flow.a mild, a moderate, and a severe impairment of functionality. This classification can be based, for example, on a restriction of the transmissible mass flow rate, whereby a mild impairment of functionality could be understood as a restriction of less than 10%, a moderate impairment of functionality as a restriction of less than 20%, and a severe impairment of functionality as a restriction of more than 50%.

[0009] The described method can preferably be used in internal combustion engines of passenger cars or trucks. However, it is also conceivable to use the described method in internal combustion engines of aircraft, ships, or the like.

[0010] With a view to a particularly precise and reliable assessment of the functionality of a line for conveying a carrier mass flow, the invention provides that the current temperature profile along the line for conveying a carrier mass flow is measured in the flow direction of the carrier mass flow upstream of an exhaust aftertreatment component and upstream of a heating element for heating the exhaust aftertreatment component. Temperature measurement in the flow direction of the carrier mass flow upstream of a heating element for heating the exhaust aftertreatment component allows, in particular, the inclusion of a temperature increase caused by the heating element. The heating element can, in particular, be in the form of an electric heating disc, and the exhaust aftertreatment component can, in particular, be designed as a catalyst.

[0011] Furthermore, for a particularly precise and reliable assessment of the functionality of a line for conveying a carrier mass flow, it offers advantages to differentiate between a first case with a deactivated heating element and a second case with an activated heating element, whereby the predefined reference temperature profile in the first case differs from that in the second case. This allows the influence of various heat sources to be taken into account. In the first case, where a heating element for heating an exhaust aftertreatment component is deactivated, heating occurs via a carrier mass flow or the carrier air, specifically through compression of the carrier mass flow or the carrier air.In the second case, where a heating element is activated to heat an exhaust aftertreatment component, the heating occurs via the radiant heat of the heating element. The conveying or compression of the carrier air can be generated by any type of pump, an (electric) exhaust gas turbocharger, a sequential turbocharging system, an electrically driven compressor, a compressor, or the like.

[0012] Within the framework of a particularly flexible and adaptable method, it can be especially advantageous if, based on the diagnosis regarding the functionality of the line for carrying a carrier mass flow, the risk of overheating of the heating element is assessed, and further measures are preferably initiated based on this assessment. For example, a system can continue to operate, at least temporarily, if the risk of overheating of the heating element, which is precisely what should be prevented, is still low.

[0013] For a quick and reliable detection of a malfunction in a pipeline that only occurs during operation and / or increases during operation, it can be particularly advantageous if the comparison of the recorded actual temperature profile with the predefined reference temperature profile is based on a profile of an actual temperature gradient with the profile of a reference temperature gradient.

[0014] Similarly, for a rapid preliminary assessment, it can be advantageous if the comparison of the recorded actual temperature profile with the predefined reference temperature profile, based on the course of the actual temperature gradient with the course of a reference temperature gradient, includes a comparison of an initial actual temperature gradient value with an initial reference temperature gradient value, wherein a preliminary diagnosis is preferably already generated by comparing the initial actual temperature gradient value with the initial reference temperature gradient value. According to a further aspect of the present invention, a computer program is provided. The computer program comprises commands which, when executed by a computer, cause the computer to perform the method described above in detail.The computer program according to the invention thus offers the same advantages as those described in detail with reference to the method according to the invention. The computer program can be implemented as computer-readable instruction code in any suitable programming language, such as Java or C++. The computer program can be stored on a computer-readable storage medium such as a data disk, a removable drive, volatile or non-volatile memory, or built-in memory / processor. The instruction code can program a computer or other programmable devices, such as a control unit, to execute the desired functions. Furthermore, the computer program can be made available on a network, such as the Internet, from which it can be downloaded by a user as needed.The computer program can be implemented in the form of software, or in the form of a computer program product using one or more special electronic circuits (i.e., in hardware), or in any hybrid form (i.e., using both software and hardware components). According to a further aspect of the present invention, a storage medium with a computer program stored thereon is provided, wherein the computer program is configured and designed to carry out a method as described above. Thus, the storage medium according to the invention also offers the advantages described above. The storage medium can be understood to be a data carrier such as a memory stick on which the computer program is stored.

[0015] Furthermore, a control unit with a computer program installed on it, configured and designed to carry out a method as described above, is provided. The control unit according to the invention also offers the advantages described above. The control unit is preferably a component of a vehicle control system or a vehicle control unit.

[0016] The invention also relates to a system according to the invention for detecting a malfunction in a line for guiding a carrier mass flow, in particular for carrying out a method described above.The system according to the invention comprises a line for guiding a carrier mass flow, a secondary air source with a secondary air guide system for supplying secondary air to the line, an exhaust aftertreatment component arranged downstream of the carrier mass flow after the line for exhaust aftertreatment, a heating element arranged between the line and the exhaust aftertreatment component for heating the exhaust aftertreatment component, and a temperature sensor arranged downstream of the carrier mass flow upstream of the heating element on the line for detecting a current actual temperature profile on the line, wherein the system is designed such that a diagnosis regarding the functionality of the line can be made based on a comparison of the detected actual temperature profile with a predefined reference temperature profile.The system described above thus offers the same advantages as those already described in relation to the inventive method, the inventive computer program or the inventive control unit.

[0017] Furthermore, it can be advantageous if at least a second line for guiding a carrier mass flow, at least a second exhaust aftertreatment component arranged downstream of the carrier mass flow after the line, and at least a second heating element arranged between the line and the exhaust aftertreatment component for heating the exhaust aftertreatment component are provided, wherein the at least second line, the at least second The exhaust aftertreatment component and the at least second heating element are preferably arranged parallel to the first line, to the first exhaust aftertreatment component and to the first heating element.

[0018] Furthermore, it can also be advantageous if at least one second temperature sensor is provided downstream of the carrier mass flow in front of the second heating element on the second line to detect a current actual temperature profile on the second line.

[0019] The invention also relates to a vehicle comprising a system as described above.

[0020] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.

[0021] They show schematically: Fig. 1 the individual steps of a method according to the invention for determining a malfunction of a line for guiding a carrier mass flow of an exhaust system that can be heated by means of a heating element, Fig. 2 Details relating to the creation of a diagnosis according to the invention with regard to the functionality of a line based on a comparison of the recorded actual temperature profile with a predefined reference temperature profile in a first case with deactivated heating element, Fig. 3 Details relating to the creation of a diagnosis according to the invention with regard to the functionality of a line based on a comparison of the recorded actual temperature profile with a predefined reference temperature profile in a second case with activated heating element, Fig. 4 a system according to the invention for determining a malfunction of a line for carrying a carrier mass flow.

[0022] Fig. Figure 1 shows the individual steps of a method according to the invention for determining a malfunction of a line 6 for guiding a carrier mass flow of an exhaust system 4 which can be heated by means of a heating element 12.

[0023] The procedure includes the steps of recording 100 of a current actual temperature profile T Ist on line 6 by means of a temperature sensor 10, a comparison 200 of the recorded actual temperature profile T Ist with a predefined reference temperature profile T Ref as well as creating a diagnosis regarding the functionality of line 6 based on a comparison of the recorded actual temperature profile T Ist with the predefined reference temperature profile T Ref .

[0024] Fig. Figure 2 shows details relating to the creation according to the invention of a diagnosis 300 with regard to the functionality of a line 6 based on a comparison of the recorded actual temperature profile T Ist with a predefined reference temperature profile T Ref in a first case with heating element 12 deactivated (see P=0).

[0025] The course of three curves shown on the left, with varying degrees of restriction of functionality (temperature profile T or secondary air mass flow mSL), is plotted on the right as the course of the change in temperature compared to the starting temperature against time (see graph top right).

[0026] Here, a diagnosis can be made, for example, by comparing the temperature increase ΔT at time x with the setpoint T. Ref this is done by T Ref with T Ist is compared.

[0027] Similarly, a diagnosis (see graph bottom right) can be made by comparing the course of the actual temperature gradient T' Ist with the course of the reference temperature gradient T' Ref or via a comparison of the initial temperature actual gradient value T' Ist-Initial with the initial temperature reference gradient value T' Ref-Initial take place.

[0028] Fig. Figure 3 shows details relating to the creation according to the invention of a diagnosis 300 with regard to the functionality of a line 6 based on a comparison of the recorded actual temperature profile T Ist with a predefined reference temperature profile T Ref in a second case with activated heating element 12 (see P≠0).

[0029] Here too, the course of three curves shown on the left, with varying degrees of functional impairment (temperature profile T and secondary air mass flow mSL), is plotted on the right as the change in temperature compared to the starting temperature against time (see graph top right), whereby a diagnosis here is made by comparing the temperature increase ΔT at time x with the setpoint T. Ref can be done by T Ref with T Ist is compared.

[0030] Likewise, a diagnosis (see graph bottom right) can also be made here by comparing the course of the actual temperature gradient T'. Ist with the course of the reference temperature gradient T' Ref or via a comparison of the initial temperature actual gradient value T' Ist-Initial with the initial temperature reference gradient value T' Ref-Initial take place.

[0031] Fig. Figure 4 shows a system 2 according to the invention for determining a malfunction of a line 6 for guiding a carrier mass flow of an exhaust system 4 of an internal combustion engine 18 which can be heated by means of a heating element 12.

[0032] As per Fig. As can be seen in Figure 4, the system 2 according to the invention comprises two lines 6 for guiding a carrier mass flow, a secondary air source 14 with a secondary air guide system 16 for supplying secondary air to the lines 6, an exhaust aftertreatment component 8 arranged downstream of the carrier mass flow after the line 6 for exhaust aftertreatment, a heating element 12 arranged between the line 6 and the exhaust aftertreatment component 8 for heating the exhaust aftertreatment component 8, and a temperature sensor 10 arranged downstream of the carrier mass flow upstream of the heating element 12 on the lines for detecting a current actual temperature profile T. Iston line 6, wherein system 2 is designed such that, based on a comparison of the recorded actual temperature profile T Ist with a predefined reference temperature profile T Ref a diagnosis regarding the functionality of line 6 can be made.

[0033] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention.

Claims

[1] Method for determining a malfunction of a line (6) for guiding a carrier mass flow of an exhaust system (4) of an internal combustion engine (18) which can be heated by means of a heating element (12), comprising the steps: - Activating a heating element (12) to heat the exhaust aftertreatment component (8), - Heating the exhaust aftertreatment component (8) via the radiant heat of the heating element (12), - Recording (100) a current actual temperature profile (T Ist ) on the line (6) by means of a temperature sensor (10), - Comparing (200) the recorded actual temperature profile (T Ist ) with a predefined reference temperature profile (T Ref ), - Creating (300) a diagnosis regarding the functionality of the line (6) based on the comparison of the recorded actual temperature profile (T Ist ) with the predefined reference temperature profile (T Ref ), where, based on the diagnosis made regarding the functionality of the line (6) for guiding a carrier mass flow, a risk of overheating of the heating element (12) is assessed, and Further measures will be initiated based on the assessment. [2] Method according to claim 1, characterized by , that the recording (100) of a current actual temperature profile (T Ist ) on the line (6) for guiding a carrier mass flow in the direction of flow of the carrier mass flow in front of an exhaust aftertreatment component (8), preferably in the direction of flow of the carrier mass flow in front of a heating element (12) for heating the exhaust aftertreatment component (8). [3] Method according to claim 1 or 2, characterized by, that with regard to the execution of the procedure a distinction is made between a first case with deactivated heating element (12) and a second case with activated heating element (12), in particular the predefined reference temperature profile (T) Ref ) in the first case from the predefined reference temperature profile (T Ref ) differs in the second case. [4] Method according to any of the preceding claims, characterized by , that comparing (200) the recorded actual temperature profile (T Ist ) with the predefined reference temperature profile (T Ref ) based on the course of an actual temperature gradient (T' Ist ) with the course of a reference temperature gradient (T' Ref ). [5] Method according to claim 4, characterized by , that comparing (200) the recorded actual temperature profile (T Ist ) with the predefined reference temperature profile (T Ref) based on the course of the actual temperature gradient (T' Ist ) with the course of a reference temperature gradient (T' Ref ) a comparison of an initial temperature actual gradient value (T' Ist-lnitial ) with an initial temperature reference gradient value (T' Ref-Initial ) includes, preferably already via the comparison of the initial temperature actual gradient value (T' lst-lnitial ) with the initial temperature reference gradient value (T' Ref-lnitial ) a preliminary diagnosis is made. [6] System (2) for detecting a malfunction in a line (6) for carrying a carrier mass flow, wherein the system (2) is configured to perform the method according to any one of claims 1 to 5, comprising: - a conduit (6) for guiding a carrier mass flow, - a secondary air source (14) with a secondary air duct system (16) for supplying secondary air to the duct (6), - an exhaust aftertreatment component (8) arranged downstream of the carrier mass flow after the line (6) for exhaust aftertreatment, - a heating element (12) arranged between the line (6) and the exhaust aftertreatment component (8) for heating the exhaust aftertreatment component (8), - a temperature sensor (10) arranged downstream of the carrier mass flow in front of the heating element (12) on the line (6) for detecting (100) a current actual temperature profile (T Ist ) on the line (6), characterized by , that the system (2) is designed such that, based on a comparison of the recorded actual temperature profile (T Ist ) with a predefined reference temperature profile (T Ref ) a diagnosis regarding the functionality of the line (6) can be made. [7] System (2) according to claim 6, characterized by, that at least a second line (6) for guiding a carrier mass flow, at least a second exhaust aftertreatment component (8) arranged downstream of the carrier mass flow after the line (6) and at least a second heating element (12) arranged between the line (6) and the exhaust aftertreatment component (8) for heating the exhaust aftertreatment component (8) is provided, wherein the at least second line (6), the at least second exhaust aftertreatment component (8) and the at least second heating element (12) are preferably arranged parallel to the first line (6), to the first exhaust aftertreatment component (8) and to the first heating element (12). [8] System (2) according to claim 7, characterized by , that at least a second temperature sensor (10) arranged downstream of the carrier mass flow upstream of the second heating element (12) on the second line (6) for recording (100) a current actual temperature profile (T Ist) is provided on the second line (6). [9] Vehicle comprising a system (2) according to any one of claims 6 to 8.

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