Combustible gas concentration detection method and device

Abstract

The present invention discloses a method and device for detecting the concentration of combustible gas. The method for detecting the concentration of combustible gas includes: obtaining the current response signal output by the combustible gas sensor, and obtaining the current reaction temperature inside the combustible gas sensor; when the difference between the current reaction temperature and the initial reaction temperature is greater than a first preset threshold, determining the first combustible gas concentration corresponding to the current reaction temperature according to the corresponding relationship between the reaction temperature and the combustible gas concentration; and determining the second combustible gas concentration corresponding to the current response signal according to the corresponding relationship between the response signal and the combustible gas concentration; performing weighted calculation on the first combustible gas concentration and the second combustible gas concentration to obtain the current combustible gas concentration. The technical solution of the embodiment of the present invention can improve the accuracy of combustible gas concentration detection.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to a method and device for detecting the concentration of combustible gas. Background Art

[0002] When the combustible gas sensor detects the combustible gas concentration, the combustible gas concentration is usually directly obtained according to the output response signal of the combustible gas sensor, resulting in low detection accuracy of the combustible gas concentration. Summary of the invention

[0003] The present invention provides a combustible gas concentration detection method and device to improve the accuracy of combustible gas concentration detection.

[0004] According to one aspect of the present invention, there is provided a method for detecting combustible gas concentration, comprising:

[0005] Obtain the current response signal output by the combustible gas sensor and obtain the current reaction temperature inside the combustible gas sensor;

[0006] When the difference between the current reaction temperature and the initial reaction temperature is greater than a first preset threshold, a first combustible gas concentration corresponding to the current reaction temperature is determined according to a corresponding relationship between the reaction temperature and the combustible gas concentration; and a second combustible gas concentration corresponding to the current response signal is determined according to a corresponding relationship between the response signal and the combustible gas concentration;

[0007] A weighted calculation is performed on the first combustible gas concentration and the second combustible gas concentration to obtain a current combustible gas concentration.

[0008] Optionally, performing weighted calculation on the first combustible gas concentration and the second combustible gas concentration to obtain a current combustible gas concentration includes:

[0009] The current combustible gas concentration is determined according to the product of the first weight and the first combustible gas concentration, and the product of the second weight and the second combustible gas concentration; wherein the sum of the first weight and the second weight is 1.

[0010] Optionally, the greater the difference between the current reaction temperature and the initial reaction temperature, the greater the first weight.

[0011] Optionally, when the difference between the current reaction temperature and the initial reaction temperature is greater than a second preset threshold, the first weight is greater than the second weight; wherein the second preset threshold is greater than the first preset threshold.

[0012] Optionally, after obtaining the current response signal output by the combustible gas sensor and obtaining the current reaction temperature inside the combustible gas sensor, the method further includes:

[0013] When the difference between the current reaction temperature and the initial reaction temperature is less than or equal to the first preset threshold, the current combustible gas concentration is determined according to the corresponding relationship between the response signal and the combustible gas concentration and the current response signal.

[0014] Optionally, the combustible gas concentration detection method further comprises: during the combustible gas concentration detection process, controlling the humidity of the gas entering the combustible gas sensor to be maintained within a preset humidity range;

[0015] and / or,

[0016] During the detection of the combustible gas concentration, the temperature of the gas entering the combustible gas sensor is controlled to be maintained within a preset temperature range.

[0017] Optionally, the combustible gas sensor comprises: a heating circuit and a detection circuit; the heating circuit comprises a heating resistor, and the detection circuit comprises a load resistor and a detection element composed of a gas-sensitive material; the heating resistor and the detection element are arranged on the same substrate; a detection voltage is applied across the detection circuit;

[0018] Get the current response signal output by the combustible gas sensor, including:

[0019] Acquire the current voltage across the load resistor as the current response signal;

[0020] Get the current reaction temperature inside the combustible gas sensor, including:

[0021] The current temperature of the heating resistor is obtained as the current reaction temperature.

[0022] Optionally, a heating voltage is connected to both ends of the heating circuit;

[0023] The combustible gas concentration detection method also includes:

[0024] During the detection process of the combustible gas concentration, the heating voltage is controlled to remain constant, and the detection voltage is controlled to remain constant.

[0025] Optionally, the process of establishing the corresponding relationship between the reaction temperature and the combustible gas concentration includes:

[0026] Introducing combustible gas into the combustible gas sensor multiple times, and recording the concentration of the combustible gas introduced each time and the reaction temperature reached inside the combustible gas sensor respectively; wherein the concentrations of the combustible gas introduced into the combustible gas sensor at least partially are different;

[0027] According to the combustible gas concentration recorded each time and the reaction temperature reached inside the combustible gas sensor, a corresponding relationship between the reaction temperature and the combustible gas concentration is formed;

[0028] and / or,

[0029] The process of establishing the corresponding relationship between the response signal and the combustible gas concentration includes:

[0030] The combustible gas is introduced into the combustible gas sensor for multiple times, and the concentration of the combustible gas introduced each time and the response signal output by the combustible gas sensor are recorded respectively; wherein the concentration of the combustible gas introduced into the combustible gas sensor for at least some times is different.

[0031] According to the combustible gas concentration recorded each time and the response signal output by the combustible gas sensor, a corresponding relationship between the response signal and the combustible gas concentration is formed.

[0032] According to another aspect of the present invention, there is provided a combustible gas concentration detection device, comprising:

[0033] An acquisition module is used to acquire a current response signal output by the combustible gas sensor and to acquire a current reaction temperature inside the combustible gas sensor;

[0034] A first calculation module is used to determine a first combustible gas concentration corresponding to the current reaction temperature according to a corresponding relationship between the reaction temperature and the combustible gas concentration when the difference between the current reaction temperature and the initial reaction temperature is greater than a first preset threshold; and determine a second combustible gas concentration corresponding to the current response signal according to a corresponding relationship between the response signal and the combustible gas concentration;

[0035] The second calculation module is used to perform weighted calculation on the first combustible gas concentration and the second combustible gas concentration to obtain a current combustible gas concentration.

[0036] The technical solution of the embodiment of the present invention makes a preliminary qualitative judgment on the concentration of the combustible gas according to the change in the current reaction temperature inside the combustible gas sensor compared to the initial reaction temperature. Since the change in the reaction temperature itself will affect the response signal value output by the combustible gas sensor, when the difference between the current reaction temperature and the initial reaction temperature is greater than the first preset threshold, it can be considered that the degree of quantitative concentration analysis using temperature has been reached. At this time, the first combustible gas concentration determined based on the current reaction temperature and the second combustible gas concentration determined based on the response signal are weightedly calculated to obtain the current combustible gas concentration. Compared with the combustible gas concentration detection only by outputting the response signal, it is equivalent to considering the influence of the reaction temperature change on the detection result, which can effectively reduce the error of the detection result, improve the accuracy of the concentration detection, and thus enhance safety.

[0037] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A flow chart of a combustible gas concentration detection method provided according to an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the structure of a combustible gas sensor provided according to an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of a circuit structure of a combustible gas sensor provided according to an embodiment of the present invention;

[0042] Figure 4 A flow chart of another combustible gas concentration detection method provided according to an embodiment of the present invention;

[0043] Figure 5 The present invention is a schematic structural diagram of a combustible gas concentration detection device provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0046] Figure 1 This is a flow chart of a combustible gas concentration detection method provided according to an embodiment of the present invention. This embodiment is applicable to the case of combustible gas concentration detection. The method can be executed by a combustible gas concentration detection device, and the combustible gas concentration detection device can be implemented in the form of hardware and / or software. Figure 1 , the combustible gas concentration detection methods include:

[0047] S101. Acquire a current response signal output by a combustible gas sensor, and acquire a current reaction temperature inside the combustible gas sensor.

[0048] For ease of explanation, let's first combine Figure 2 and Figure 3 The structure and working process of the combustible gas sensor are briefly described. Figure 2 The combustible gas sensor includes a housing 100 and a detection component 101. The housing 100 is, for example, a metal cap with an air inlet hole on the top, and the detection component 101 is disposed inside the housing 100. The interior of the combustible gas sensor specifically refers to the internal space of the housing 100. The detection component 101 is, for example, a circuit board based on a ceramic substrate. Figure 3 Detailed circuit structure of the detection component 101 is shown. Figure 3 The detection component 101 of the combustible gas sensor includes: a heating circuit 10 and a detection circuit 11; the heating circuit 10 includes a heating resistor R H The detection circuit 11 includes a load resistor R2 connected in series and a detection element R composed of a gas-sensitive material. S .

[0049] A heating voltage VH is applied to both ends of the heating circuit 10, for example, a heating resistor R H A heating voltage VH is applied across the two ends, so that the heating resistor R H The temperature rises, causing the detection element R SThe temperature required to react with the combustible gas is reached. A detection voltage VCC is applied across the detection circuit 11, and the voltage V across the load resistor R2 is used as the response signal output by the combustible gas sensor. When combustible gas is introduced into the combustible gas sensor, the detection element R S The gas-sensitive material in the detector reacts with the combustible gas, causing the detection element R S The resistance value of the load resistor R2 changes, which causes the voltage V at both ends of the load resistor R2 to change. The reaction degree of different concentrations of combustible gas and gas-sensitive materials is different, resulting in the detection element R S The change in resistance value is different, so the change in voltage V across the load resistor R2 is also different. Accordingly, the response signal output by the combustible gas sensor can represent the concentration of the combustible gas. For example, the combustible gas sensor can be a semiconductor sensor.

[0050] Since the detection element R S When the gas-sensitive material in the sensor reacts with the combustible gas, it releases heat, which will cause the reaction temperature inside the combustible gas sensor to rise. The gas-sensitive material has different characteristics at different reaction temperatures, which affects the change of its resistance value, thereby affecting the response signal output by the combustible gas sensor. Therefore, it is necessary to detect the current reaction temperature of the combustible gas sensor.

[0051] Specifically, obtaining the current response signal output by the combustible gas sensor is to obtain the current voltage across the load resistor R2. The current reaction temperature inside the combustible gas sensor can be measured by a temperature detection device in combination with a hardware circuit, and then the current reaction temperature can be obtained according to the output result of the temperature detection device.

[0052] S102. When the difference between the current reaction temperature and the initial reaction temperature is greater than a first preset threshold, the first combustible gas concentration corresponding to the current reaction temperature is determined according to the correspondence between the reaction temperature and the combustible gas concentration; and the second combustible gas concentration corresponding to the current response signal is determined according to the correspondence between the response signal and the combustible gas concentration.

[0053] The initial reaction temperature is the temperature of the heating resistor R when there is no combustible gas inside the combustible gas sensor. H The temperature reached by heating according to the heating voltage VH applied at both ends. The first preset threshold value can be understood as the minimum temperature difference value that can clearly determine the presence of combustible gas based on the change in reaction temperature, that is, the minimum temperature difference value that can characterize that the temperature change is caused by the reaction of combustible gas and gas-sensitive material. The first preset threshold value is greater than the change value caused by the natural fluctuation of the reaction temperature.

[0054] Specifically, the reaction temperature and the combustible gas concentration are in a one-to-one correspondence, that is, when the reaction temperature is different, the corresponding concentration of the combustible gas passing through the combustible gas sensor is different. When the current reaction temperature inside the combustible gas sensor is determined, the combustible gas concentration obtained by substituting the current reaction temperature into the corresponding relationship between the reaction temperature and the combustible gas concentration is the first combustible gas concentration. The response signal and the combustible gas concentration are in a one-to-one correspondence, that is, when the response signal is different, the corresponding concentration of the combustible gas passing through the combustible gas sensor is different. When the current response signal output by the combustible gas sensor is determined, the combustible gas concentration obtained by substituting the current response signal into the corresponding relationship between the response signal and the combustible gas concentration is the second combustible gas concentration.

[0055] Exemplarily, since the response signal output by the combustible gas sensor is different when the concentration of the combustible gas is different, and the change in the response signal relative to the initial response signal is also different, the corresponding relationship between the response signal and the combustible gas concentration here can be the relationship between the response signal output by the combustible gas sensor itself and the combustible gas concentration, or the relationship between the change in the response signal output by the combustible gas sensor compared to the initial response signal and the combustible gas concentration. Among them, the initial response signal can be specifically understood as the response signal of the combustible gas sensor when the concentration of the combustible gas is 0. Similarly, the corresponding relationship between the reaction temperature and the combustible gas concentration can be the relationship between the reaction temperature itself and the combustible gas concentration, or the relationship between the change in the reaction temperature compared to the initial reaction temperature and the combustible gas concentration.

[0056] Exemplarily, the correspondence between the reaction temperature and the combustible gas concentration can be stored in the form of a graph or table, etc.; it can also be stored as the detection sensitivity of the reaction temperature to the combustible gas concentration, and the correspondence between the reaction temperature and the combustible gas concentration can be characterized by a formula. In the actual detection process, the combustible gas concentration can be obtained by looking up a chart or substituting it into a formula. When the current reaction temperature is not recorded in the graph or table, the combustible gas concentration at the reaction temperature closest to the current reaction temperature can be selected as the first combustible gas concentration, or the data recorded in the graph or table can be fitted to obtain the combustible gas concentration at the current reaction temperature from the fitted data as the first combustible gas concentration. Similarly, the storage and use process of the correspondence between the response signal and the combustible gas concentration is similar to the above process, and will not be repeated here.

[0057] S103: Perform weighted calculation on the first combustible gas concentration and the second combustible gas concentration to obtain a current combustible gas concentration.

[0058] Specifically, the weights of the first combustible gas concentration and the second combustible gas concentration can be determined according to the change in reaction temperature, that is, according to the difference between the current reaction temperature and the initial reaction temperature. For example, the greater the change in reaction temperature, the more obvious the temperature effect, and the greater the weight of the first combustible gas concentration, the smaller the weight of the second combustible gas concentration.

[0059] The technical solution of the embodiment of the present invention makes a preliminary qualitative judgment on the concentration of the combustible gas according to the change in the current reaction temperature inside the combustible gas sensor compared to the initial reaction temperature. Since the change in the reaction temperature itself will affect the response signal value output by the combustible gas sensor, when the difference between the current reaction temperature and the initial reaction temperature is greater than the first preset threshold, it can be considered that the degree of quantitative analysis of the concentration using temperature has been reached. At this time, the first combustible gas concentration determined based on the current reaction temperature and the second combustible gas concentration determined based on the response signal are weightedly calculated to obtain the current combustible gas concentration. Compared with the combustible gas concentration detection only by outputting the response signal, it is equivalent to considering the influence of the reaction temperature change on the detection result, which can effectively reduce the error of the detection result, improve the accuracy of the concentration detection, and thus enhance safety.

[0060] Optionally, based on the above embodiment, weighted calculation is performed on the first combustible gas concentration and the second combustible gas concentration to obtain the current combustible gas concentration, including:

[0061] The current combustible gas concentration is determined according to the product of the first weight and the first combustible gas concentration, and the product of the second weight and the second combustible gas concentration, wherein the sum of the first weight and the second weight is 1 to ensure that the weighted calculation result is reliable.

[0062] The first weight is the proportion of the first combustible gas concentration in the calculation of the current combustible gas concentration, which is used to characterize the correction ability of the first combustible gas concentration in determining the current combustible gas concentration. For example, the larger the first weight is, the stronger the correction ability of the first combustible gas concentration is. The first weight is, for example, associated with the size of the difference between the current reaction temperature inside the combustible gas sensor and the initial reaction temperature. The second weight is the proportion of the second combustible gas concentration in the calculation of the current combustible gas concentration.

[0063] Optionally, based on the above embodiments, the greater the difference between the current reaction temperature and the initial reaction temperature, the greater the first weight.

[0064] In the absence of combustible gas, the reaction temperature inside the combustible gas sensor remains relatively stable, for example, stable at the initial reaction temperature. When combustible gas is introduced into the combustible gas sensor, the detection element R SThe gas-sensitive material in the heating resistor R H The temperature also rises accordingly. When the combustible gas concentration is different, the degree of reaction with the gas-sensitive material is different, which makes the current reaction temperature inside the combustible gas sensor different, and the difference with the initial reaction temperature is also different. Accordingly, the concentration of the combustible gas can be characterized by the difference between the current reaction temperature and the initial reaction temperature inside the combustible gas sensor. Specifically, the larger the difference between the current reaction temperature and the initial reaction temperature, the more heat is released by the combustible gas and the gas-sensitive material. Since the gas-sensitive material has different characteristics at different reaction temperatures, the larger the temperature change, the greater the deviation of the concentration result directly obtained based on the response signal. Therefore, the larger the difference between the current reaction temperature and the initial reaction temperature, the larger the first weight is set, which can make the correction ability of the first combustible gas concentration in determining the current combustible gas concentration stronger.

[0065] Then, by setting the first weight to be associated with the difference between the current reaction temperature and the initial reaction temperature, for example, the larger the difference, the larger the first weight. This is equivalent to the embodiment of the present invention measuring the reaction temperature in real time, obtaining the temperature change of the gas-sensitive material, and determining the degree of influence of the temperature change on the characteristics of the gas-sensitive material, thereby using the corresponding weight to assist in correcting the combustible gas concentration detection result and improve the accuracy of combustible gas detection.

[0066] Optionally, based on the above embodiments, when the difference between the current reaction temperature and the initial reaction temperature is greater than a second preset threshold, the first weight is greater than the second weight; wherein the second preset threshold is greater than the first preset threshold.

[0067] Among them, the second preset threshold can be specifically understood as the difference critical value when the change in reaction temperature changes from a non-dominant position to a dominant position when judging the combustible gas concentration. The gas concentration corresponding to the response signal is usually the judgment result at the guidance temperature of the data manual, and the influence of the reaction temperature change is not considered; when the reaction temperature changes drastically, the temperature has a great influence on the characteristics of the gas-sensitive material, so that the gas concentration obtained according to the response signal has a large deviation. At this time, the gas concentration can be determined mainly based on the reaction temperature. Furthermore, when the temperature changes drastically, the small error of temperature detection can be ignored, and the credibility of the gas concentration determined by the temperature is higher than that when the temperature changes slightly, which can ensure the accuracy of the concentration detection result.

[0068] It is understandable that the above-mentioned preset thresholds and weights are only for illustrative purposes and are not intended to limit the present invention. In practical applications, the number and actual values ​​of the preset thresholds of the temperature difference can be determined according to the characteristics of the combustible gas sensor and the actual measurement results, and the value ranges and specific weight values ​​of the first weight and the second weight that meet different preset threshold conditions can be set accordingly.

[0069] Figure 4 This is a flow chart of another combustible gas concentration detection method provided according to an embodiment of the present invention, referring to Figure 4 Based on the above embodiments, the combustible gas concentration detection method includes:

[0070] S201. Obtain a current response signal output by the combustible gas sensor, and obtain a current reaction temperature inside the combustible gas sensor.

[0071] S202, determine whether the difference between the current reaction temperature and the initial reaction temperature is ≤ a first preset threshold; if so, execute S203; if not, execute S204.

[0072] S203: Determine the current combustible gas concentration according to the corresponding relationship between the response signal and the combustible gas concentration and the current response signal.

[0073] Specifically, when the difference between the current reaction temperature and the initial reaction temperature is less than or equal to the first preset threshold, the concentration of the combustible gas may not be accurately detected based on the change in the reaction temperature inside the combustible gas sensor. Therefore, the concentration of the combustible gas is detected directly through the response signal output by the combustible gas sensor. In addition, when the change in the reaction temperature itself is small, since the reaction temperature has little effect on the characteristics of the gas-sensitive material, the effect of the change in the characteristics on the response signal is also relatively weak and can be ignored. At this time, directly determining the concentration of the combustible gas through the response signal output by the combustible gas sensor does not affect the accuracy of the detection result. Exemplarily, when the current response signal output by the combustible gas sensor is determined, the current concentration of the combustible gas can be obtained by substituting the current response signal into the corresponding relationship between the response signal and the combustible gas concentration.

[0074] S204, determining a first combustible gas concentration corresponding to the current reaction temperature according to the corresponding relationship between the reaction temperature and the combustible gas concentration; and determining a second combustible gas concentration corresponding to the current response signal according to the corresponding relationship between the response signal and the combustible gas concentration.

[0075] S205: Perform weighted calculation on the first combustible gas concentration and the second combustible gas concentration to obtain a current combustible gas concentration.

[0076] This embodiment provides a combustible gas concentration detection method through steps S201-S205, which can improve the accuracy of combustible gas concentration detection.

[0077] Based on the above embodiments, optionally, during the detection of the combustible gas concentration, the humidity of the gas entering the combustible gas sensor is controlled to be maintained within a preset humidity range. By controlling the combustible gas sensor to operate in an environment with relatively stable humidity, the influence of humidity changes on the detection results can be reduced or even eliminated, thereby improving the accuracy of the combustible gas concentration measurement.

[0078] Among them, the preset humidity range can be specifically understood as a humidity range set according to the working characteristics of the sensor, the application environment, the impact of humidity on the sensor performance and the industry standards. In this embodiment, exemplarily, the preset humidity range can be to set the humidity to a fixed value (for example, the humidity value recorded in the sensor data manual, or to reduce the humidity to 0) or to fix the humidity range to a smaller range by technical means. Exemplarily, a desiccant or a gas filter device can be used to control the humidity of the gas entering the combustible gas sensor. Among them, the desiccant can include silica gel, molecular sieve, calcium chloride, etc., and the gas filter device can include a membrane filter, a drying tube, etc., which is not specifically limited in this embodiment.

[0079] By setting a desiccant or gas filter to control the humidity of the gas entering the combustible gas sensor, water vapor in the combustible gas can be effectively removed and humidity fluctuations can be reduced. At the same time, by controlling the humidity, corrosion, oxidation, and other chemical reactions inside the sensor caused by moisture can be avoided, thereby extending the service life of the combustible gas sensor and reducing maintenance and replacement costs.

[0080] On the basis of the above embodiments, optionally, in the process of detecting the combustible gas concentration, the temperature of the gas entering the combustible gas sensor is controlled to be maintained within a preset temperature range. Through this setting, the influence of the intake air temperature change on the detection result can be eliminated to ensure that the temperature rise of the heating resistor in the combustible gas sensor comes from the combustion of the combustible gas contained in the intake air, thereby ensuring the accuracy of the combustible gas sensor in detecting the combustible gas concentration.

[0081] On the basis of the above embodiment, optionally, obtaining a current response signal output by the combustible gas sensor includes: obtaining a current voltage across the load resistor as the current response signal.

[0082] Based on the above embodiment, optionally, there are multiple methods for obtaining the current reaction temperature inside the combustible gas sensor, which are described below respectively.

[0083] In one embodiment, optionally, an additional temperature sensor and its peripheral circuits can be integrated inside the combustible gas sensor, the current reaction temperature can be measured by the temperature sensor, and a voltage signal or digital signal proportional to the temperature can be directly output, and the current reaction temperature can be obtained based on the voltage signal or digital signal.

[0084] In another embodiment, optionally, the current reaction temperature can be determined based on the temperature of a heating resistor (such as a thermistor), which is described in detail below.

[0085] Specifically, the heating resistor R H With the detection element R S Set on the same substrate, so the heating resistor R H The temperature and detection element R S The temperature of the heating resistor R H The temperature of the detection element R is increased according to the heating voltage VH. S When combustible gas is introduced into the combustible gas sensor, the detection element R S The gas-sensitive material in the heating resistor R H The temperature of the heating resistor R H The temperature and detection element R S The temperature of the heating resistor R changes synchronously, and the two temperatures remain the same. H The temperature and detection element R S The temperature of the detection element R S The temperature is the reaction temperature. H With the detection element R S It can be set on both the front and back sides of the substrate.

[0086] Then, obtaining the current reaction temperature inside the combustible gas sensor includes: obtaining the current temperature of the heating resistor as the current reaction temperature.

[0087] Continue to refer Figure 3 Specifically, the heating circuit 10 further includes: a current detection component for detecting current flowing through the heating resistor R H There are many structures of current detection components and detection processes, several of which are described below, but they are not intended to limit the present invention.

[0088] See also Figure 3 In one embodiment, the current detection component may optionally include a voltage divider resistor R1, and the resistance of the voltage divider resistor R1 is known. H The heating circuit 10 is formed in series, and the heating voltage VH can be applied to the voltage divider resistor R1 and the heating resistor R H Correspondingly, obtaining the current temperature of the heating resistor includes: detecting the current voltage across the voltage divider resistor R1, and determining the current flowing through the heating resistor R according to the current voltage and the resistance value of the voltage divider resistor R1. HThe current current of the heating resistor R is determined according to the current voltage across the voltage divider resistor R1 and the heating voltage VH. H The current voltage is based on the heating resistor R H The current voltage and current determine the heating resistance R H The current resistance value of the heating resistor R H With a fixed temperature-resistance curve, when the heating resistor R H When the resistance value is known, the heating resistance R can be determined by the temperature-resistance curve H The current temperature. For example, the heating resistor R H It can be a metal resistor, whose resistance increases with increasing temperature.

[0089] In another optional embodiment of the present invention, the current detection component may include a current transformer, and the detection component of the current transformer may be sleeved on the heating resistor R H The power supply line is used to detect the current flowing through the heating resistor R H In this case, the heating voltage VH is directly applied to the heating resistor R H Correspondingly, the current temperature of the heating resistor is obtained, including: directly measuring the current flowing through the heating resistor R through the current transformer H The current of the heating resistor R H The current and heating voltage VH determine the heating resistance R H The current resistance value of the heating resistor R H The corresponding relationship between the resistance value and temperature and the heating resistance R H The current resistance value of the heating resistor R H The current temperature.

[0090] On the basis of the above embodiments, optionally, during the detection of the combustible gas concentration, the combustible gas sensor controls the heating voltage VH to be constant so that the heating resistor R H The current and heating resistance R H The resistance values ​​of the load resistor R2 are uniquely corresponding, which is beneficial to improving the detection accuracy of the reaction temperature. In addition, the detection voltage VCC is controlled to be constant, so that the voltage V at both ends of the load resistor R2 is only affected by the detection element R S The influence of resistance value change can avoid the influence of detection voltage VCC change on the detection result.

[0091] Alternatively, the detection voltage VCC and the heating voltage VH may be the same.

[0092] Based on the above embodiments, optionally, the process of establishing the corresponding relationship between the reaction temperature and the combustible gas concentration includes:

[0093] 1) The combustible gas is introduced into the combustible gas sensor for multiple times, and the concentration of the combustible gas introduced each time and the reaction temperature reached inside the combustible gas sensor are recorded respectively; wherein the concentrations of the combustible gas introduced into the combustible gas sensor for at least some times are different.

[0094] The concentration of the combustible gas introduced into the combustible gas sensor can be precisely controlled by a mixed gas generator. The concentration of the combustible gas introduced into the combustible gas sensor at least partially can be different: the concentration of the combustible gas introduced into the combustible gas sensor is different each time. At this time, the reaction temperature reached in the combustible gas sensor corresponding to the combustible gas of different concentrations is recorded. Alternatively, for each of the multiple different concentrations, the same concentration of combustible gas can be introduced into the combustible gas sensor multiple times. At this time, the reaction temperature reached in the combustible gas sensor corresponding to the multiple times of the same concentration of combustible gas is recorded, and the average of the reaction temperatures obtained multiple times is taken as the reaction temperature at the combustible gas concentration, which is conducive to avoiding the influence of accidental factors.

[0095] 2) Based on the combustible gas concentration recorded each time and the reaction temperature reached inside the combustible gas sensor, a corresponding relationship between the reaction temperature and the combustible gas concentration is formed.

[0096] In one embodiment, optionally, the corresponding relationship between the response signal and the combustible gas concentration can be directly extracted from the data sheet of the combustible gas sensor.

[0097] In another embodiment, optionally, the corresponding relationship between the response signal and the combustible gas concentration can also be established by self-test, which can avoid the error problem caused by the deviation of the corresponding relationship between the response signal and the combustible gas concentration of the combustible gas sensor from the calibration relationship due to the influence of the preparation process or working conditions. Specifically, the process of establishing the corresponding relationship between the response signal and the combustible gas concentration includes:

[0098] 1) The combustible gas is introduced into the combustible gas sensor for multiple times, and the concentration of the combustible gas introduced each time and the response signal output by the combustible gas sensor are respectively recorded; wherein the concentrations of the combustible gas introduced into the combustible gas sensor at least partially are different.

[0099] The different concentrations of the combustible gas introduced into the combustible gas sensor at least partially may be: the concentrations of the combustible gas introduced into the combustible gas sensor are different each time, and in this case, the response signals output by the combustible gas sensor corresponding to the combustible gas of different concentrations are recorded. Alternatively, for each of the multiple different concentrations, the same concentration of combustible gas may be introduced into the combustible gas sensor multiple times, and in this case, the response signals output by the combustible gas sensor corresponding to the multiple times of the same concentration of combustible gas are recorded, and the average of the response signals obtained multiple times is taken as the response signal at the combustible gas concentration, which is conducive to avoiding the influence of accidental factors.

[0100] Specifically, in the process of establishing the corresponding relationship between the response signal and the combustible gas concentration, the reaction temperature of the combustible gas sensor can be fixed or adjusted by a heating device, so that the change in the response signal is only related to the influencing factor of the combustible gas concentration.

[0101] 2) Based on the combustible gas concentration recorded each time and the response signal output by the combustible gas sensor, a corresponding relationship between the response signal and the combustible gas concentration is formed.

[0102] It can be understood that the process of establishing the correspondence between the reaction temperature and the combustible gas concentration and the correspondence between the response signal and the combustible gas concentration can be established only once; or, considering the aging problem of the combustible gas sensor due to long-term use, the relevant correspondence can be updated once every preset time period to improve the accuracy of combustible gas concentration detection.

[0103] An embodiment of the present invention further provides a combustible gas concentration detection device. The combustible gas concentration detection device provided by the embodiment of the present invention can execute the combustible gas concentration detection method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0104] Figure 5 FIG. 1 is a schematic diagram of a combustible gas concentration detection device according to an embodiment of the present invention. Figure 5 The device includes: an acquisition module 20, a first calculation module 30 and a second calculation module 40.

[0105] The acquisition module 20 is used to acquire the current response signal output by the combustible gas sensor and to acquire the current reaction temperature inside the combustible gas sensor. The first calculation module 30 is used to determine the first combustible gas concentration corresponding to the current reaction temperature according to the corresponding relationship between the reaction temperature and the combustible gas concentration when the difference between the current reaction temperature and the initial reaction temperature is greater than the first preset threshold value; and to determine the second combustible gas concentration corresponding to the current response signal according to the corresponding relationship between the response signal and the combustible gas concentration. The second calculation module 40 is used to perform weighted calculation on the first combustible gas concentration and the second combustible gas concentration to obtain the current combustible gas concentration.

[0106] Based on the above embodiment, optionally, the second calculation module 40 is specifically used to determine the current combustible gas concentration based on the product of the first weight and the first combustible gas concentration, and the product of the second weight and the second combustible gas concentration; wherein the sum of the first weight and the second weight is 1.

[0107] Based on the above embodiment, optionally, the combustible gas concentration detection device also includes: a third calculation module, which is used to determine the current combustible gas concentration according to the correspondence between the response signal and the combustible gas concentration, and the current response signal when the difference between the current reaction temperature and the initial reaction temperature is less than or equal to the first preset threshold.

[0108] On the basis of the above embodiment, optionally, the combustible gas concentration detection device further includes: a first control module, which is used to control the humidity of the gas entering the combustible gas sensor to be within a preset humidity range during the detection of the combustible gas concentration.

[0109] On the basis of the above embodiment, optionally, the acquisition module 20 is specifically used to acquire the current voltage across the load resistor as the current response signal, and to acquire the current temperature of the heating resistor as the current reaction temperature.

[0110] On the basis of the above embodiment, optionally, the combustible gas concentration detection device further includes: a second control module, which is used to control the heating voltage to be constant and the detection voltage to be constant during the detection process of the combustible gas concentration.

[0111] On the basis of the above embodiment, optionally, the combustible gas concentration detection device further includes: a relationship establishment module, specifically including a first relationship establishment unit and / or a second relationship establishment unit.

[0112] The first relationship establishing unit is used to record the concentration of the combustible gas introduced each time and the reaction temperature reached inside the combustible gas sensor when the combustible gas is introduced into the combustible gas sensor for multiple times; wherein the concentration of the combustible gas introduced into the combustible gas sensor for at least some times is different. And according to the combustible gas concentration recorded each time and the reaction temperature reached inside the combustible gas sensor, a corresponding relationship between the reaction temperature and the combustible gas concentration is formed.

[0113] The second relationship establishing unit is used to record the concentration of the combustible gas introduced each time and the response signal output by the combustible gas sensor when the combustible gas is introduced into the combustible gas sensor multiple times; wherein the concentration of the combustible gas introduced into the combustible gas sensor at least some times is different; and based on the combustible gas concentration recorded each time and the response signal output by the combustible gas sensor, a corresponding relationship between the response signal and the combustible gas concentration is formed.

[0114] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0115] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting combustible gas concentration, characterized in that: include: Obtain the current response signal output by the combustible gas sensor and obtain the current reaction temperature inside the combustible gas sensor; When the difference between the current reaction temperature and the initial reaction temperature is greater than a first preset threshold, a first combustible gas concentration corresponding to the current reaction temperature is determined according to a corresponding relationship between the reaction temperature and the combustible gas concentration; and a second combustible gas concentration corresponding to the current response signal is determined according to a corresponding relationship between the response signal and the combustible gas concentration; A weighted calculation is performed on the first combustible gas concentration and the second combustible gas concentration to obtain a current combustible gas concentration.

2. The combustible gas concentration detection method according to claim 1, characterized in that: The first combustible gas concentration and the second combustible gas concentration are weightedly calculated to obtain a current combustible gas concentration, including: The current combustible gas concentration is determined according to the product of the first weight and the first combustible gas concentration, and the product of the second weight and the second combustible gas concentration; wherein the sum of the first weight and the second weight is 1.

3. The combustible gas concentration detection method according to claim 2, characterized in that: The greater the difference between the current reaction temperature and the initial reaction temperature, the greater the first weight.

4. The combustible gas concentration detection method according to claim 2, characterized in that: When the difference between the current reaction temperature and the initial reaction temperature is greater than a second preset threshold, the first weight is greater than the second weight; wherein the second preset threshold is greater than the first preset threshold.

5. The combustible gas concentration detection method according to claim 1, characterized in that: After obtaining the current response signal output by the combustible gas sensor and obtaining the current reaction temperature inside the combustible gas sensor, it also includes: When the difference between the current reaction temperature and the initial reaction temperature is less than or equal to the first preset threshold, the current combustible gas concentration is determined according to the corresponding relationship between the response signal and the combustible gas concentration and the current response signal.

6. The combustible gas concentration detection method according to any one of claims 1 to 5, characterized in that: Also includes: During the detection of the combustible gas concentration, the humidity of the gas entering the combustible gas sensor is controlled to be within a preset humidity range; and / or, During the detection of the combustible gas concentration, the temperature of the gas entering the combustible gas sensor is controlled to be maintained within a preset temperature range.

7. The combustible gas concentration detection method according to claim 1, characterized in that: The combustible gas sensor comprises: a heating circuit and a detection circuit; the heating circuit comprises a heating resistor, and the detection circuit comprises a load resistor and a detection element composed of a gas-sensitive material; the heating resistor and the detection element are arranged on the same substrate; a detection voltage is applied to both ends of the detection circuit; Get the current response signal output by the combustible gas sensor, including: Acquire the current voltage across the load resistor as the current response signal; Get the current reaction temperature inside the combustible gas sensor, including: The current temperature of the heating resistor is obtained as the current reaction temperature.

8. The combustible gas concentration detection method according to claim 7, characterized in that: Both ends of the heating circuit are connected to a heating voltage; The combustible gas concentration detection method also includes: During the detection process of the combustible gas concentration, the heating voltage is controlled to be constant, and the detection voltage is controlled to be constant.

9. The combustible gas concentration detection method according to claim 1, characterized in that: The process of establishing the corresponding relationship between the reaction temperature and the combustible gas concentration includes: Introducing combustible gas into the combustible gas sensor multiple times, and recording the concentration of the combustible gas introduced each time and the reaction temperature reached inside the combustible gas sensor respectively; wherein the concentrations of the combustible gas introduced into the combustible gas sensor at least partially are different; According to the combustible gas concentration recorded each time and the reaction temperature reached inside the combustible gas sensor, a corresponding relationship between the reaction temperature and the combustible gas concentration is formed; and / or, The process of establishing the corresponding relationship between the response signal and the combustible gas concentration includes: Introducing combustible gas into the combustible gas sensor for multiple times, and recording the concentration of the combustible gas introduced each time and the response signal output by the combustible gas sensor respectively; wherein the concentrations of the combustible gas introduced into the combustible gas sensor for at least some times are different; According to the combustible gas concentration recorded each time and the response signal output by the combustible gas sensor, a corresponding relationship between the response signal and the combustible gas concentration is formed.

10. A combustible gas concentration detection device, characterized in that: include: An acquisition module is used to acquire a current response signal output by the combustible gas sensor and to acquire a current reaction temperature inside the combustible gas sensor; A first calculation module is used to determine a first combustible gas concentration corresponding to the current reaction temperature according to a corresponding relationship between the reaction temperature and the combustible gas concentration when the difference between the current reaction temperature and the initial reaction temperature is greater than a first preset threshold; and determine a second combustible gas concentration corresponding to the current response signal according to a corresponding relationship between the response signal and the combustible gas concentration; The second calculation module is used to perform weighted calculation on the first combustible gas concentration and the second combustible gas concentration to obtain a current combustible gas concentration.

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