Method for diagnosing gas concentration sensor, gas concentration sensor, computer program and computer readable medium

Abstract

The invention relates to a method for diagnosing a gas concentration sensor on the basis of a determined temperature profile. The invention further relates to a gas concentration sensor, a computer program and a computer readable medium.

Description

Field of the Invention

[0001] The present invention relates to a method for diagnosing a gas concentration sensor, a gas concentration sensor, a computer program, and a computer-readable medium. The gas concentration sensor is in particular a gas concentration sensor configured to determine the gas concentration of a gas based on the thermal conductivity and / or heat capacity of the gas. Background Art

[0002] Publications US10 112 486 B2, DE 10 2019 204 284 A1, JP 2019 128182A, US 9 027386 B2, and US2009 00 61 261A1 disclose gas sensors.

[0003] In particular, it is disadvantageous for the devices in the prior art that the diagnosis of such gas sensors is only possible with a correspondingly high additional technical effort for the diagnostic means. Summary of the Invention

[0004] Accordingly, the object of the present invention is to provide a method which is characterized in particular by its simple and / or cost-effective implementation. Alternatively or additionally, the object of the present invention is to provide an alternative method.

[0005] A further object of the present invention is to provide a gas concentration sensor, a computer program, and a computer-readable medium.

[0006] The object with respect to the method is solved by a method having the features of claim 1.

[0007] An embodiment of the present invention relates to a method for diagnosing a gas concentration sensor. The gas concentration sensor is configured to determine the gas concentration of a gas based on the thermal conductivity and / or heat capacity of the gas, wherein the gas concentration sensor includes a heater and a temperature probe field, and the temperature probe field has a plurality of regions, each region having at least one temperature probe. The method includes the steps of generating a heat flow by means of the heater, determining the temperature distribution on the temperature probe field by means of the temperature probes in the respective regions, and diagnosing the gas concentration sensor based on the determined temperature distribution. For this purpose, it is preferred if the heater influences or can influence the temperature or the temperature distribution by means of the heat flow generated thereby.

[0008] It is thus possible to perform a low-cost and simple diagnosis of the gas concentration sensor. In other words, in the case of a uniform temperature distribution, the gas concentration sensor is considered to be functioning correctly, while in the case of a non-uniform temperature distribution, the gas concentration sensor is considered to be defective. Instead of considering the defective gas concentration sensor, alternatively, it is conceivable to consider a source of interference. Such a source of interference may be formed, for example, by water droplets or dirt particles on the temperature probe field or in the immediate vicinity of the temperature probe. For example, the water droplets may be formed due to condensation.

[0009] Such a gas concentration sensor is based, in particular, on the fact that the gas concentration sensor utilizes the thermal conductivity and / or heat capacity of the gas or gas mixture to be measured in order to determine the concentration of, for example, hydrogen or nitrogen in the gas or gas mixture. For this purpose, for example, the heater is activated and its surroundings are gradually heated. The time elapsed until a specific temperature can be determined by means of the temperature probe is a characteristic value for the gas concentration of, for example, hydrogen or nitrogen in the gas or gas mixture to be measured. Alternatively, it is conceivable to use the temperature determined by means of the temperature probe as a characteristic value for the gas concentration. The two characteristic values are related to the thermal conductivity and / or heat capacity of the gas or gas mixture. The thermal conductivity and / or heat capacity of the gas or gas mixture is in turn related to the gas concentration, for example, the gas concentration of hydrogen or nitrogen in the gas or gas mixture. In other words, the gas concentration can be determined in this way.

[0010] It is particularly advantageous if the gas concentration sensor is configured to determine the gas concentration of hydrogen and / or nitrogen in a gas or gas mixture or the corresponding gas flow or gas mixture flow.

[0011] The gas is preferably a gas mixture or the corresponding flow, which in particular comprises hydrogen and / or nitrogen.

[0012] The determination is preferably carried out by measuring with the gas concentration sensor.

[0013] It is preferred if multiple temperature probes or a large number of temperature probes are provided per area. Thereby, a higher resolution of the temperature distribution can be determined by means of the temperature probes. Furthermore, it is preferred if the same number of temperature probes is provided for each area. Thereby, the temperature distribution on the temperature probe field can be determined uniformly.

[0014] Furthermore, it is preferred if the heater is an electric heater or an electric heating element. Preferably, it is a resistive heating element or a PTC heating element. The temperature measurement values preferably exist as electronic signals, for example as analog or digital signals. Such signals preferably correspond to temperature values in Kelvin or degrees Celsius.

[0015] Another embodiment is characterized in that the method includes: determining a first temperature measurement value by means of a temperature probe in a first region, determining a second temperature measurement value by means of a temperature probe in a second region, determining a temperature measurement value difference from the determined temperature measurement values, and determining the temperature distribution based on the temperature measurement value difference. In other words, the basic concept on which the method is based is to compare the existing temperature distribution with the determined temperature distribution.

[0016] It may also be preferred that the temperature measurement values exist as absolute values or differences. The difference is in particular understood in this case as the difference from a reference value. The reference value can preferably be understood as the temperature of the heater or the ambient temperature of the gas concentration sensor.

[0017] Furthermore, it is advantageous if the temperature measurement value difference is the difference between the determined temperature measurement values from each other.

[0018] Another embodiment is characterized in that the method includes: if the determined temperature measurement value difference exceeds a pre-given threshold, identifying a fault or interference source of the gas concentration sensor. Alternatively or additionally, not exceeding this temperature measurement value difference or another temperature measurement value difference may lead to identifying a malfunction. The temperature measurement value difference is preferably a numerical value.

[0019] It may also be preferred that if the determined temperature measurement value difference corresponds to the threshold or is below the threshold, identifying the correct functional mode of the gas concentration sensor. Alternatively or additionally, in this case, it can be identified that there is no interference source at all.

[0020] Preferably, the threshold for the temperature measurement value difference is at most 15%, 10%, 5%, 3%, 1%, 0.05% or 0.01% of the lowest or highest temperature measurement value in units of the temperature unit Kelvin, and the temperature measurement values are used as the basis for determining the temperature measurement value difference.

[0021] Another embodiment is characterized in that the threshold is related to the position of the temperature probes relative to each other and / or the position of the temperature probes relative to the heater and / or the distance of the temperature probes relative to the heater and / or the distance of the temperature probes relative to each other. This correlation is particularly necessary if the temperature probes by means of which the temperature measurement values are determined and thus the temperature measurement value difference is determined are unevenly positioned or spaced relative to the heater.

[0022] Preferably, the region and / or the temperature probes of the region are arranged such that the region and / or the temperature probes of the region determine the same temperature measurement value in the case of a uniform temperature distribution, and thus determine a uniform temperature distribution.

[0023] Another embodiment is characterized in that a diagnostic signal is generated based on the determined temperature distribution. Such a diagnostic signal preferably exists as an electrical signal, for example as an analog or digital signal. The diagnostic signal is preferably forwarded via a signal line to a control device or an evaluation unit, which can be part of the control device. Such a control device or such an evaluation unit can generate an error report (Fehlermeldung) with the received diagnostic signal. Such an error report can be stored, for example, on the control device or stored on the control device and read at a later point in time, for example during an inspection or within the scope of a repair measure.

[0024] It can also be preferred that the diagnostic signal includes information about a fault of the gas concentration sensor.

[0025] Furthermore, it is advantageous if the diagnostic signal is generated only when the determined difference in temperature measurements exceeds a predefined threshold. In other words, in this case, the diagnostic signal is generated only when a fault or interference source of the gas concentration sensor is detected. This is particularly beneficial because it is generally assumed that the gas concentration sensor functions error - free.

[0026] Another embodiment is characterized in that when the determined difference in temperature measurements exceeds a predefined threshold, the predefined threshold or another predefined threshold, a cleaning method for cleaning the gas concentration sensor is initialized. In other words, when a fault or interference source of the gas concentration sensor is detected, the cleaning method for cleaning the gas concentration sensor is started. Such a cleaning method is preferably a method that includes preferably operating the heater with maximum heating power and / or over a predefined time interval. Thereby, water droplets on the temperature probe field can be evaporated or dirt particles can be burned off, which may be the cause of the fault of the gas concentration sensor.

[0027] Such a cleaning method is preferably initialized by the control device. For this purpose, it is particularly advantageous if the control device initializes the cleaning method in response to the diagnostic signal.

[0028] Another embodiment is characterized in that the temperature probe is configured as a thermoelectric temperature sensor. Thus, the temperature probe can output an electrical signal, for example an analog or digital signal, based on the temperature at the temperature probe. In this case, for example, a temperature sensor including a resistance thermometer or a thermal element.

[0029] Another embodiment is characterized in that the temperature probe field is arranged in a temperature probe field plane, where the heater is intersected by a dividing plane extending perpendicular to the temperature probe field plane, and areas of the temperature probe field plane are arranged on one side and the other side of the dividing plane.

[0030] Preferably, the heater and / or the zone and / or the temperature probe are arranged such that during the generation of a heat flow by means of the heater, a uniform temperature distribution and / or a uniform temperature distribution can be determined on one side and on the other side of the dividing plane. For this purpose, it is particularly advantageous if the heater is constructed symmetrically with respect to the dividing plane.

[0031] In the case where a further dividing plane is provided, this dividing plane is the first dividing plane.

[0032] Another embodiment is characterized in that the heater is intersected by a further dividing plane which extends perpendicular to the temperature probe field plane and perpendicular to the first dividing plane, wherein regions of the temperature probe field plane are arranged on one side and on the other side of the further dividing plane.

[0033] Preferably, the heater and / or the zone and / or the temperature probe are arranged such that during the generation of a heat flow by means of the heater, a uniform temperature distribution and / or a uniform temperature distribution can be determined on one side and on the other side of the further dividing plane. For this purpose, it is particularly advantageous if the heater is constructed symmetrically with respect to the further dividing plane.

[0034] Another embodiment is characterized in that a gas or a gas mixture flows along the heater and / or the temperature probe field in the direction of extension of the dividing plane or in the direction of extension of the first dividing plane.

[0035] Advantageously, the dividing plane or the first dividing plane forms a symmetry plane of the flow profile of the gas flow or the gas mixture flow of the gas mixture. This ensures a uniform temperature distribution on both sides of the dividing plane.

[0036] Another embodiment is characterized in that a first region is arranged on one side of the dividing plane or the first dividing plane, wherein a second region is arranged on the other side of the dividing plane or the first dividing plane.

[0037] Another embodiment is characterized in that the first and second regions are arranged on the same side of the second dividing plane. The first and second regions are preferably arranged on the side of the dividing plane facing away from the direction of flow of the gas or the gas mixture. This ensures that the diagnosis of the gas concentration sensor is possible even in the case of strong flow.

[0038] Another embodiment is characterized in that the first region and the second region are two regions separated from each other by at least one dividing plane. In other words, in the case of this embodiment, it is possible that the first region and the second region are separated from each other by the dividing plane, by the first dividing plane, by the second dividing plane, or by both the first dividing plane and the second dividing plane.

[0039] In the case of this embodiment, preferably the gas concentration sensor is arranged such that the gas concentration of the gas or gas mixture is determined as statically as possible, i.e. without a significant relative movement of the gas or gas mixture relative to the heater and / or the plane of the temperature probe field for the measurement. This is possible, for example, when the gas concentration sensor is arranged outside the gas channel through which the gas or gas mixture flows and / or is fluidly connected to the gas channel by means of a stationary chamber (Ruheraum).

[0040] The task associated with the gas concentration sensor is solved by providing a gas concentration sensor having a heater, a temperature probe field, and means, the temperature probe field having a plurality of regions, each region including at least one temperature probe, the means being adapted such that the means performs the steps of the method. The method is preferably a method according to the present invention.

[0041] It may also be preferred that the gas concentration sensor includes additional features already mentioned with respect to the previously described method.

[0042] Furthermore, it is advantageous if the gas concentration sensor is fluidly coupled to the gas channel.

[0043] Furthermore, it is advantageous if the gas concentration sensor or the gas concentration sensor together with the gas channel is provided as part of a fuel cell system. It is also conceivable to provide a vehicle or a stationary energy generation device having such a fuel cell system.

[0044] The task associated with the computer program is solved by providing a computer program including instructions that cause the gas concentration sensor to perform the method steps. The gas concentration sensor is preferably a gas concentration sensor according to the present invention.

[0045] The task associated with the computer-readable medium is solved by providing a computer-readable medium on which the computer program is stored. The computer-readable medium can be a volatile memory or a permanent memory. The computer program is preferably a computer program according to the present invention.

[0046] Advantageous refinements of the invention are described in the dependent claims and in the following description of the figures. Description of the Drawings

[0047] The present invention will be explained in detail below with reference to embodiments with reference to the drawings. In the drawings:

[0048] Figure 1 A motor vehicle is shown,

[0049] Figure 2Shows an embodiment of the method according to the invention,

[0050] Figure 3 A diagram showing three planes, and

[0051] Figure 4 A gas concentration sensor according to the invention is shown. Detailed implementation

[0052] Figure 1 A motor vehicle 1 is shown, which has a fuel cell system 2, a gas concentration sensor 3 according to the invention which is part of the fuel cell system 2, and a control device 4 coupled to the gas concentration sensor 3. Alternatively, it is conceivable to use such a fuel cell system 2 with the associated gas concentration sensor 3 and control device 4 in a stationary energy generation device.

[0053] Figure 2 An embodiment of the method according to the invention is shown. First, the method is started at A. Then a heat flow is generated by means of a heater at B. In response thereto, the temperature distribution is determined on a temperature probe field at C. This determination includes determining the temperature measurement values of different regions of the temperature probe field. Then, if the temperature measurement value difference already determined from the temperature measurement values exceeds a pre-given threshold, a diagnosis is performed at D, which includes ascertaining a fault or interference source of the gas concentration sensor at which the method is carried out. If no fault or interference source is ascertained, the method is preferably restarted with a regular time delay. Alternatively, it is conceivable to carry out the method when starting the fuel cell system, and the gas concentration sensor used for carrying out the method belongs to this fuel cell system. If a fault or interference source is ascertained, the information can be stored on a storage medium at E, which can belong to the control device, for example. Additionally or alternatively, a cleaning method is initialized at F. The cleaning method can be, for example, targeted heating of the gas concentration sensor by means of a heater. In this way, dirt particles or water droplets on the temperature probe field can be removed. After this cleaning method, the method according to the invention is restarted and repeated until the interference source or fault is eliminated.

[0054] Figure 3 Three planes TFE, UE1, UE2 extending perpendicular to each other are shown. The temperature probe field plane TFE extends in the X-Y plane, while the first dividing plane UE1 extends in the X-Z plane, and the other dividing plane UE2 extends in the Y-Z plane. These planes TFE, UE1, UE2 are used for better understanding Figure 4 .

[0055] Figure 4 An embodiment of the gas concentration sensor 3 according to the invention is shown. Shown is perpendicular to from Figure 3View of the temperature probe field plane. It can be seen the temperature probe field 7, which extends in the temperature probe field plane. From Figure 3 Two dividing planes from Figure 4 intersect the heater 5 of the gas concentration sensor 3 and divide the temperature probe field 7 of the gas concentration sensor 3 into four regions 6a to 6d. The extension of the dividing planes is indicated by the X-axis and the Y-axis in Figure 3 , where one of the regions respectively has temperature probes 8a to 8d. The heater 5 is arranged symmetrically with respect to the two dividing planes from

[0056] The different features of the respective embodiments can also be combined with each other

[0057] In particular, Figures 1 to 4 the embodiments of

[0058] List of reference numerals

[0059] 1 Motor vehicle

[0060] 2 Hydrogen system

[0061] 3 Gas concentration sensor

[0062] 4 Control device

[0063] 5 Heater

[0064] 6a - 6d Regions

[0065] 7 Temperature probe field

[0066] 8a - 8d Temperature probes

[0067] 9 Flow profile

[0068] UE1 First dividing plane

[0069] UE2 Another dividing plane

[0070] TFE Temperature probe field plane

[0071] A Start

[0072] B Generate heat flow

[0073] C Determine temperature distribution

[0074] D Diagnosis

[0075] E Storage

[0076] F Initialize the cleaning method.

Claims

1. A method for diagnosing a gas concentration sensor, wherein the gas concentration sensor is configured to determine the gas concentration of the gas based on the thermal conductivity and / or heat capacity of the gas, wherein the gas concentration sensor includes a heater and a temperature probe field, wherein the temperature probe field has a plurality of regions, and each region has at least one temperature probe, The method includes the steps of: - generating a heat flow by means of the heater, - determining the temperature distribution on the temperature probe field by means of the temperature probes in the corresponding regions, and - diagnosing the gas concentration sensor based on the determined temperature distribution.

2. The method according to claim 1, wherein the method includes the following additional method steps: - determining a first temperature measurement value by means of the temperature probe in the first region, - determining a second temperature measurement value by means of the temperature probe in the second region, - determining a temperature measurement value difference from the determined temperature measurement values, and - determining the temperature distribution based on the temperature measurement value difference.

3. The method according to claim 2, wherein the method includes the following additional method steps: - if the determined temperature measurement value difference exceeds a pre-given threshold, identifying a fault or interference source of the gas concentration sensor.

4. The method according to claim 3, wherein the threshold is related to the relative positions of the temperature probes to each other and / or the position of the temperature probes relative to the heater and / or the distance of the temperature probes relative to the heater and / or the distance of the temperature probes relative to each other.

5. The method according to any one of the preceding claims, wherein a diagnostic signal is generated based on the determined temperature distribution.

6. The method according to any one of claims 3 to 5, wherein when the determined temperature measurement value difference exceeds a pre-given threshold, the pre-given threshold or another pre-given threshold, a cleaning method for cleaning the gas concentration sensor is initialized.

7. The method according to any one of the preceding claims, wherein the temperature probes are configured as thermoelectric temperature sensors.

8. The method according to any one of the preceding claims, wherein the temperature probe field is arranged in a temperature probe field plane, wherein the heater is intersected by a dividing plane extending perpendicular to the temperature probe field plane, wherein the regions of the temperature probe field plane are arranged on one side and the other side of the dividing plane.

9. The method according to claim 8, wherein the heater is intersected by another dividing plane, and the other dividing plane extends perpendicular to the temperature probe field plane and perpendicular to the first dividing plane, wherein the regions of the temperature probe field plane are arranged on one side and the other side of the other dividing plane.

10. The method according to claim 8 or 9, wherein the gas flows along the heater and / or the temperature probe field in the extending direction of the dividing plane or in the extending direction of the first dividing plane.

11. The method according to claim 10, wherein the first region is arranged on one side of the dividing plane or the first dividing plane, wherein the second region is arranged on the other side of the dividing plane or the first dividing plane.

12. The method according to claim 11, wherein the first region and the second region are arranged on the same side of the second dividing plane.

13. The method according to any one of claims 8 to 11, wherein the first region and the second region are two regions separated from each other by at least one dividing plane.

14. A gas concentration sensor having a heater, a temperature probe field and means, the temperature probe field having a plurality of regions, each region including at least one temperature probe, the means being adapted such that the means performs the steps of the method according to any one of the preceding claims.

15. A computer program comprising instructions that cause the device of claim 14 to perform the method steps according to any one of claims 1 to 14.

16. A computer-readable medium having stored thereon the computer program according to claim 15.

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