Method for diagnosing hydrogen sensor, hydrogen sensor, computer program and computer readable medium

Abstract

The invention relates to a method for diagnosing a hydrogen sensor (4), comprising the following steps: inducing a temperature change (7) in a measurement chamber by means of a heater; determining a diagnostic value (8) in the measurement chamber by means of the temperature sensor; a diagnosis (11, 12) is determined as a function of the diagnostic value. The invention also relates to a hydrogen sensor (4), a computer program (16) and a computer readable medium (5).

Description

Technical Field

[0001] The invention relates to a method for diagnosing a hydrogen sensor, a hydrogen sensor, a computer program and a computer-readable medium. Background Art

[0002] To determine the hydrogen concentration of a gas, a hydrogen sensor usually has a measurement chamber to provide protection from the influence of gas flow. The entrance of the measurement chamber is usually sealed by a gas-permeable but liquid-impermeable diaphragm to prevent liquid or foreign matter from entering the measurement chamber. Unexpected foreign matter deposition or liquid accumulation may occur on the diaphragm, thereby affecting the measurement of the hydrogen concentration in the gas.

[0003] Document US Pat. No. 9,702,836 B2 relates to a sensor with an error detection function. Summary of the invention

[0004] The object of the present invention is to realize an alternative method which is distinguished by its simple implementability.

[0005] The first object is achieved by a method having the features of claim 1 .

[0006] One embodiment of the present invention relates to a method for diagnosing a hydrogen sensor,

[0007] The hydrogen sensor consists of a measuring chamber, a heater and a temperature sensor.

[0008] The measuring chamber is in fluid communication with the environment of the hydrogen sensor via a measuring chamber opening.

[0009] The measuring chamber opening is closed by a diaphragm.

[0010] The membrane is permeable to gases but impermeable to liquids.

[0011] The method comprises the following steps:

[0012] - causing a temperature change in the measuring chamber by means of a heater;

[0013] - Determine diagnostic values ​​in the measuring chamber with the aid of a temperature sensor;

[0014] - Determining a diagnosis based on the diagnostic value.

[0015] In this way, the diagnosis of the hydrogen sensor can be performed without providing an additional sensor element, because the diagnosis is performed using the existing device for determining the hydrogen concentration in the gas using the hydrogen sensor.

[0016] The determination of the diagnosis preferably involves the determination of a diagnosis of the hydrogen sensor, particularly preferably a diagnosis of its membrane and / or its measuring chamber opening.

[0017] It is particularly advantageous if the heater and the temperature sensor are arranged in the measuring chamber. This allows for faster heating and more accurate measurements.

[0018] It is also advantageous if the hydrogen sensor is a sensor for determining the hydrogen concentration in a gas, in particular a thermal conductivity sensor.

[0019] Preferably, the hydrogen sensor is a thermal conductivity sensor / heat capacity sensor, which uses the significantly higher heat capacity of hydrogen compared to other components in the measured gas to measure the hydrogen concentration in the measured gas.

[0020] It is also preferred if the hydrogen sensor comprises a sensor housing which in particular delimits a measuring chamber and / or comprises a measuring chamber opening, preferably a measuring chamber opening which is located on a surface of the sensor housing.

[0021] Furthermore, it is advantageous if the temperature change comprises heating or cooling. Heating, ie, temperature increase, can be performed by operating the heater, whereas cooling can be performed by shutting down the heater if the heater was previously in operation.

[0022] The determination preferably involves a measurement.

[0023] Furthermore, it is preferred if the method is carried out before the hydrogen concentration of the gas is determined, so that the functionality of the sensor can be checked before use.

[0024] Furthermore, it is preferred if the diagnostic value is derived in response to a temperature change in the measuring chamber.

[0025] Furthermore, it is preferred if the diagnosis is determined in response to the derivation of a diagnostic value.

[0026] A preferred embodiment is characterized in that the temperature change comprises operating the heater at a constant heating power, heating by means of the heater by increasing the heating power, causing cooling by reducing the heating power of the heater and / or deactivating the heater.

[0027] A further preferred embodiment is characterized in that the derived diagnostic value comprises a temperature, a temperature change rate, a temperature change curve and / or a time value. For example, the temperature, in particular the temperature in the measuring chamber, can be derived or measured after a certain period of time. The temperature change rate is the amount of temperature change per unit time. The temperature change curve refers to the process of temperature change within a period of time. If only the temperature is used as a diagnostic value, the speed is particularly fast, and at the same time, the temperature change rate or the temperature change curve can draw particularly accurate conclusions. The time value can be, for example, the time required from the initial temperature to the target temperature. If the diaphragm or the measuring chamber opening is blocked by foreign matter or liquid, the measuring chamber will heat up faster than when the diaphragm and the measuring chamber opening are unobstructed, that is, the required time is shorter.

[0028] The various possible diagnostic values ​​mentioned above are preferably relative values ​​or absolute values.

[0029] Preferably, an initial temperature in the measuring chamber is determined before the method is started or before the temperature change begins and is particularly preferably taken into account when determining the diagnosis or when determining the diagnostic value.

[0030] Another preferred embodiment is characterized in that the method includes the step of comparing the derived diagnostic value with the stored diagnostic value. The stored diagnostic value is, for example, a diagnostic value or a comparative value previously derived by an experiment. Alternatively, it can be a diagnostic value or a comparative value previously derived by the method of the present invention. In other words, it is a diagnostic value or a comparative value historically derived at a previous time, which is used as the stored diagnostic value or comparative value. Preferably, the comparison is performed after (the diagnostic value) is derived and / or before the diagnosis is determined.

[0031] Another preferred embodiment is characterized in that the stored diagnostic value and the derived diagnostic value are of the same type, for example, the derived temperature curve is compared with the stored temperature curve, or the derived time value is compared with the stored time value.

[0032] A further preferred embodiment is characterized in that a diagnostic determination is made when the determined diagnostic value reaches, falls below and / or exceeds a stored diagnostic value. These variants make it possible to handle different application conditions of the sensor.

[0033] Another preferred embodiment is characterized in that the temperature change in the measuring chamber and the determination of the diagnostic value are carried out simultaneously, staggered or immediately one after the other. Thus, the mutual influence between the temperature change and the determination of the (diagnostic value) can be changed.

[0034] Another preferred embodiment is characterized in that the temperature change in the measuring chamber and the derivation of the diagnostic value start and / or end simultaneously, staggered or immediately one after the other. This also allows the mutual influence between the temperature change and the derivation to be varied.

[0035] Another preferred embodiment is characterized in that when the temperature in the measuring chamber is lower than or higher than a specific temperature, the temperature change in the measuring chamber and / or the derivation of the diagnostic value is started, and / or when the temperature in the measuring chamber is lower than or higher than a specific temperature, the temperature change in the measuring chamber and / or the derivation of the diagnostic value is ended.

[0036] A further preferred embodiment is characterized in that the determination of the diagnosis includes the determination of whether the membrane is blocked by foreign bodies or by liquids. These two determinations relate to two typical causes that have an influence on the diagnostic value obtained. Therefore, based on the diagnostic value, in particular when comparing the diagnostic value obtained with the stored diagnostic value, a conclusion can be drawn about one of the two states, wherein the stored diagnostic value corresponds to one of the two states.

[0037] Furthermore, it is advantageous that if it is determined that the diaphragm is blocked by foreign matter or liquid, the hydrogen sensor is rejected or cannot be used for measurement. Preferably, if the method according to the invention determines that the diaphragm is blocked by foreign matter or liquid, no measurement is possible. For this purpose, it is recommended to repeat the method several times, in particular at intervals.

[0038] Alternatively, it is conceivable to mark, indicate or store the measured value of the hydrogen concentration in the measured gas obtained by the hydrogen sensor after the diaphragm is blocked by foreign matter or liquid as unreliable or erroneous. This can prevent the measured value from being used to regulate or control a system, in particular a fuel cell system.

[0039] As an alternative or supplement to one of the two aforementioned embodiments, it is conceivable to increase the heating power of the heater to remove foreign matter or liquid. Alternatively or supplementarily, it is conceivable to temporarily increase the flow rate of the gas to be measured to remove foreign matter or liquid.

[0040] Furthermore, it is particularly preferred that the method is terminated if a diagnosis is made according to which the diaphragm or the measuring chamber opening is free of liquid or foreign matter.

[0041] A further preferred embodiment is characterized in that the method is a computer-implemented method.

[0042] The objects concerning a hydrogen sensor are achieved by providing a hydrogen sensor comprising a measuring chamber, a heater and a temperature sensor, wherein the measuring chamber is in fluid communication with the environment of the hydrogen sensor by means of a measuring chamber opening, wherein the measuring chamber opening is closed by a membrane, wherein the membrane is permeable to gases and impermeable to liquids, and means adapted to perform the steps of the method according to the invention.

[0043] It is also preferred if the hydrogen sensor is also connected to a control unit which in particular comprises stored diagnostic values. It is also advantageous if the control unit comprises an evaluation unit which carries out the determination of the diagnosis and / or compares the derived diagnostic value with stored diagnostic values.

[0044] It is particularly advantageous if the heater and the temperature sensor are arranged in the measuring chamber. This allows for faster heating and more accurate measurements.

[0045] It is also advantageous if the hydrogen sensor is a sensor for determining the hydrogen concentration in a gas. Such a sensor is used in the exhaust gas line of a fuel cell system.

[0046] It is also preferred if the hydrogen sensor comprises a sensor housing which delimits, in particular, a measuring chamber.

[0047] With regard to the computer program, the object is achieved in that the computer program comprises commands which cause the hydrogen sensor according to the invention to carry out the steps of the method according to the invention.

[0048] The object with respect to a computer-readable medium is achieved by providing a computer-readable medium on which a computer program according to the invention is stored.

[0049] It is also preferred if the computer readable medium is part of the controller, for example as a permanent or temporary memory.

[0050] Advantageous developments of the invention are described in the dependent claims and in the following description of the figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0052] Figure 1 A motor vehicle is shown,

[0053] Figure 2 A channel with a hydrogen sensor is shown,

[0054] Figure 3 A method flow chart is shown. DETAILED DESCRIPTION

[0055] Figure 1 The motor vehicle 1 is shown having an electric drive and a fuel cell system 2. The fuel cell system 2 comprises a channel 3 which is designed as an exhaust gas channel of the fuel cell system 2, in which the hydrogen concentration can be determined by means of a hydrogen sensor 4.

[0056] Figure 2 Shows Figure 1The hydrogen sensor 4 is fixed in an opening of the channel wall of the channel 3 and comprises a measuring chamber which is fluidically connected to the channel 3 through a measuring chamber opening. The measuring chamber opening is closed by a diaphragm 5 which is permeable to gas but not to liquid. A heater and a temperature sensor / thermistor are installed in the measuring chamber of the hydrogen sensor 4. Since hydrogen has a higher heat capacity than other components of the measured gas, the concentration of hydrogen in the measured gas can be obtained by using a heater and a temperature sensor. In other words, the hydrogen sensor 4 is a thermal conductivity sensor. The hydrogen sensor 4 is connected to a controller 14, in which a computer-readable medium 15 in the form of a permanent memory is integrated. A computer program 16 is stored on the computer-readable medium 15, which includes commands for causing the hydrogen sensor 4 and / or an evaluation unit integrated in the controller 14 to perform the steps of the method according to the present invention.

[0057] Figure 3 The method according to the present invention is shown in Figure 1 and Figure 2 Flow chart when used in a device of . First, the method 6 is started, and then a temperature change 7 in the measuring chamber of the hydrogen sensor is achieved by a heater in the measuring chamber. The temperature change 7 involves a heating process that increases the temperature in the measuring chamber. Simultaneously with the temperature change 7, a diagnostic value 8 is obtained by the temperature sensor. The obtained diagnostic value is the time required for a certain temperature to be reached in the measuring chamber. The diagnostic value is then compared 10 with the stored diagnostic value 9. If the obtained diagnostic value is lower than the stored diagnostic value 9, it means that the temperature in the measuring chamber rises faster than usual, because the stored diagnostic value 9 corresponds to the time value that can be obtained when the diaphragm of the hydrogen sensor is not blocked by liquid or foreign matter. If the obtained diagnostic value is lower than the stored diagnostic value 9, it is therefore determined 11 that the diaphragm or the measuring chamber opening is blocked by foreign matter or liquid. The method can then be restarted later to determine whether the diagnosis still exists. In addition, it can also be considered to continue to operate the heater and remove liquid or foreign matter. In addition, it can also be considered to start a cleaning program to clean the diaphragm or the measuring chamber opening. It can also be considered that the measured value of the hydrogen concentration in the gas to be measured is stored incorrectly and cannot be used for subsequent methods. If the diagnostic value determined at least corresponds to the stored diagnostic value 9, it is determined 12 that the diaphragm or the measuring chamber opening is free of liquid or foreign matter. The method is then terminated 13 so that a measuring method for determining the hydrogen concentration in the gas to be measured can be started.

[0058] The different features of the individual embodiments may also be combined with one another.

[0059] Figures 1 to 3 The features of the exemplary embodiments are in particular not intended to be limiting but rather serve to illustrate the concept of the invention.

[0060] Reference numerals list

[0061] 1 Motor Vehicle

[0062] 2 Fuel Cell System

[0063] 3 channels

[0064] 4 Hydrogen sensor

[0065] 5 Diaphragm

[0066] 6. Getting Started

[0067] 7 Temperature changes

[0068] 8 Conclusion

[0069] 9 Stored diagnostic values

[0070] 10. Comparison

[0071] 11 OK

[0072] 12 OK

[0073] 13 End

[0074] 14 Controller

[0075] 15 Computer readable medium

[0076] 16 Computer Programs

Claims

1. A method for diagnosing a hydrogen sensor (4), The hydrogen sensor (4) comprises a measuring chamber, a heater and a temperature sensor, The measuring chamber is in fluid communication with the environment of the hydrogen sensor via a measuring chamber opening. The measuring chamber opening is closed by a diaphragm (5). The membrane (5) is permeable to gases but impermeable to liquids. The method comprises the following steps: - causing a temperature change in the measuring chamber by means of a heater (7); - determining a diagnostic value (8) in the measuring chamber by means of a temperature sensor; - determining a diagnosis (11, 12) based on the diagnostic value.

2. The method according to claim 1, characterized in that The temperature change (7) includes: operating the heater at a constant heating power, heating with the aid of the heater by increasing the heating power, causing cooling by reducing the heating power of the heater and / or deactivating the heater.

3. The method according to claim 1 or 2, characterized in that The obtained diagnostic value includes temperature, temperature change rate, temperature change curve and / or time value.

4. The method according to any one of the preceding claims, characterized in that The method comprises the step of comparing (10) the derived diagnostic value with a stored diagnostic value (9).

5. The method according to claim 4, characterized in that The stored diagnostic value (9) is of the same type as the derived diagnostic value.

6. The method according to any one of the preceding claims, characterized in that If the determined diagnostic value reaches, falls below and / or exceeds a stored diagnostic value (9), a corresponding diagnosis is determined.

7. The method according to any one of the preceding claims, characterized in that The temperature change (7) in the measuring chamber and the determination of the diagnostic value (8) are carried out simultaneously, at an offset time or immediately one after the other.

8. The method according to any one of the preceding claims, characterized in that The temperature change (7) in the measuring chamber and the determination of the diagnostic value (8) start and / or end simultaneously, at a different time or immediately afterwards.

9. The method according to any one of the preceding claims, characterized in that When the temperature in the measuring chamber is lower than or higher than a specific temperature, the temperature change (7) in the measuring chamber is started and / or the derivation of the diagnostic value (8) is started, and / or when the temperature in the measuring chamber is lower than or higher than a specific temperature, the temperature change (7) in the measuring chamber is ended and / or the derivation of the diagnostic value (8) is ended.

10. The method according to any one of the preceding claims, characterized in that The diagnostic determination (11, 12) includes determining whether the diaphragm is blocked by foreign matter or fluid.

11. The method according to any one of the preceding claims, characterized in that The method is a computer-implemented method.

12. A hydrogen sensor (4) comprising a measuring chamber, a heater and a temperature sensor, The measuring chamber is in fluid communication with the environment of the hydrogen sensor (4) via a measuring chamber opening. The measuring chamber opening is closed by a diaphragm (5). The membrane (5) is permeable to gases but impermeable to liquids. The hydrogen sensor further comprises means adapted to perform the steps (7, 8, 10, 11, 12) of the method according to any of the preceding claims.

13. A computer program (16) comprising instructions for causing an apparatus according to claim 12 to perform the steps (7, 8, 10, 11, 12) of the method according to any one of claims 1 to 11.

14. A computer-readable medium (15) on which a computer program (16) according to claim 13 is stored.

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