Gas Sensing Device and Gas Concentration Sensing Method

Abstract

The present invention discloses a gas sensing device and a gas concentration sensing method, wherein the gas sensing device is suitable for sensing the concentration of a target gas in a gas to be measured. The gas sensing device includes a dielectric layer, a reference sensing element part, a target sensing element part, and a controller. The dielectric layer is disposed on a surface, the reference sensing element part and the target sensing element part are disposed on the bearing side of the dielectric layer, and the bearing side faces away from this surface. The reference sensing element part includes a first conductive layer and a first sensing layer with low sensitivity to the target gas. The target sensing element part includes a second conductive layer and a second sensing layer with high sensitivity to the target gas. The controller obtains the impedance values of the first and second conductive layers and calculates the concentration value of the target gas according to the impedance values and a relationship function.

Description

Technical Field

[0001] The present invention relates to sensing a target gas, and more particularly to an automatically calibrated gas sensing device and a calibration method thereof. Background Art

[0002] Gas sensing devices are widely used in wearable devices and portable products, and are developing towards miniaturization, low power consumption, high sensitivity, and high stability.

[0003] A metal oxide (MOX) gas sensing device uses a heater to heat a sensing material. When oxygen adsorbs to the sensing material, its resistance increases. When the target gas reacts with the oxygen ions adsorbed on the surface of the sensing material, the oxygen ions desorb and its resistance decreases. Therefore, the concentration value of the target gas can be estimated by detecting the resistance value of the sensing material.

[0004] However, due to variations in temperature or humidity in the environment, an unstable oxygen adsorption phenomenon is likely to occur, and the sensing material is also easily poisoned by siloxane and occupies the oxygen adsorption position. Therefore, the above situation will cause variations in the initial resistance of the sensing material. In addition, the sensitivity of the gas sensing device will also be affected by factors such as the aging of the sensing material itself, incomplete burn-in of the sensor itself, and the aforementioned siloxane poisoning, resulting in abnormal conditions. In short, when using a metal oxide gas sensing device to detect the concentration of a target gas, both the initial resistance and the sensitivity of the gas sensing device will affect the detection accuracy due to environmental factors or time factors. Summary of the Invention

[0005] In view of this, the present invention provides a gas sensing device and a gas concentration sensing method capable of automatic calibration, which can improve the stability of the gas sensing device and extend its service life.

[0006] A gas concentration sensing method according to an embodiment of the present invention is applicable to a gas sensing device capable of sensing the concentration of a target gas in a gas to be measured. The gas sensing device includes a reference sensing material part, a target sensing material part, and a controller. The sensitivity of the reference sensing material part to the target gas is lower than that of the target sensing material part to the target gas. The gas concentration sensing method includes: when the reference sensing material part and the target sensing material part are in contact with the gas to be measured, detecting, by the controller, a measured reference impedance value of the reference sensing material part and a measured target impedance value of the target sensing material part; calculating, by the controller, a reference variation coefficient based on the reference impedance value and an original reference impedance value corresponding to the reference sensing material part; and calculating, by the controller, a target gas concentration value based on the reference variation coefficient, a relationship function, the measured target impedance value, and a target gas concentration conversion function, where the relationship function is the correlation between the reference sensing material part and the target sensing material part.

[0007] A gas concentration sensing method according to an embodiment of the present invention is applicable to a gas sensing device capable of sensing the concentration of a target gas in a gas to be measured. The gas sensing device includes a reference sensing element part, a target sensing element part, and a controller. The sensitivity of the reference sensing element part to the target gas is lower than that of the target sensing element part to the target gas. The gas concentration sensing method includes: an impedance value acquisition stage, when the reference sensing element part and the target sensing element part are in contact with the gas to be measured, the controller acquires a plurality of impedance values from the reference sensing element part and the target sensing element part; a partition calculation stage, the controller calculates a plurality of predicted target impedance values according to a plurality of relationship functions based on these impedance values, where these relationship functions and these predicted target impedance values all correspond to a plurality of specified concentration values; a partition comparison stage, the controller compares these predicted target impedance values with a measurement target value to select one of these specified concentration values, where the measurement target value is one of these impedance values and corresponds to the target sensing element part; and a concentration calculation stage, the controller calculates a target gas concentration value according to one of a plurality of target variation coefficients and the measurement target impedance value, where the one of these target variation coefficients corresponds to the one of these specified concentration values.

[0008] A gas concentration sensing method according to an embodiment of the present invention is applicable to a gas sensing device capable of sensing the concentration of a target gas in a gas to be measured. The gas sensing device includes a first reference sensing element part, a second reference sensing element part, a target sensing element part, and a controller. The sensitivity of the first reference sensing element part to the target gas and the sensitivity of the second reference sensing element part to the target gas are both lower than that of the target sensing element part to the target gas. The gas concentration sensing method includes: an impedance value acquisition stage, when the reference sensing element part and the target sensing element part are in contact with the gas to be measured, the controller acquires a plurality of impedance values from the first reference sensing element part, the second reference sensing element part, and the target sensing element part; a partition calculation stage, the controller calculates a plurality of partition reference values according to at least one of these impedance values related to the first reference sensing element part and the second reference sensing element part and a plurality of relationship functions, where these relationship functions and these partition reference values all correspond to a plurality of specified concentration values; a partition comparison stage, the controller compares these partition reference values with a comparison reference value to select one of these specified concentration values; and a concentration calculation stage, the controller calculates a target gas concentration value according to a target variation coefficient and the measurement target impedance value, where the target variation coefficient corresponds to the one of these specified concentration values.

[0009] A gas sensing device described according to an embodiment of the present invention is applicable to sensing the concentration of a target gas in a gas to be measured. The gas sensing device includes: a dielectric layer disposed on a surface, the dielectric layer having a bearing side facing away from the surface; a reference sensing element portion disposed on the bearing side, the reference sensing element portion including a first sensing layer and a first conductive layer; a target sensing element portion disposed on the bearing side, the reference sensing element portion including a second sensing layer and a second conductive layer; and a controller electrically connected to the first conductive layer and the second conductive layer, the controller detecting a measured reference impedance value of the first conductive layer and a measured target impedance value of the second conductive layer, and calculating a target gas concentration value of the target gas based on an original reference impedance value of the reference sensing element portion, a relationship function associated with the reference sensing element portion and the target sensing element portion, the measured reference impedance value, and the measured target impedance value; wherein the sensitivity of the reference sensing element portion to the target gas is lower than the sensitivity of the target sensing element portion to the target gas.

[0010] In summary, the gas sensing device and gas concentration sensing method capable of automatic calibration proposed by the present invention use the reference sensing element portion to provide self-compensating information to the target sensing element portion, so that the drifted resistance value can be calibrated. In addition, the present invention can dynamically correct the standard curve pre-established by the gas sensing device according to the resistance value and concentration value after each calibration, so as to provide a more accurate gas concentration sensing result for the next sensing.

[0011] The above description of the present disclosure and the following description of the embodiments are used to demonstrate and explain the spirit and principle of the present invention, and provide a further explanation of the claims of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a block diagram of the gas sensing device according to the first embodiment of the present invention;

[0013] Figure 2 is a side view of the heater, dielectric layer, reference sensing element portion, and target sensing element portion;

[0014] Figure 3A is a flowchart of the first embodiment of the gas concentration sensing method of the present invention;

[0015] Figure 3B is a detailed flowchart of step S34;

[0016] Figure 4 is a flowchart of the gas concentration sensing method applicable to the first embodiment of the present invention;

[0017] Figure 5A is a flowchart of the second embodiment of the gas concentration sensing method of the present invention;

[0018] Figure 5B It is a detailed flowchart of step S44;

[0019] Figure 6 It is a structural diagram of the gas sensing device according to the second embodiment of the present invention;

[0020] Figure 7 It is a side view of the heater, dielectric layer, first reference sensing element part, first target sensing element part, second reference sensing element part and second target sensing element part;

[0021] Figure 8 It is a flowchart of the gas concentration sensing method applicable to the second embodiment of the present invention;

[0022] Figure 9A It is a flowchart of the gas concentration sensing method according to the first embodiment of the present invention;

[0023] Figure 9B It is a detailed flowchart of step S74;

[0024] Figure 10A It is a flowchart of the gas concentration sensing method according to the second embodiment of the present invention;

[0025] Figure 10B It is a detailed flowchart of step S84;

[0026] Figure 11A It is a flowchart of the gas concentration sensing method according to the third embodiment of the present invention;

[0027] Figure 11B It is a detailed flowchart of step S94;

[0028] Figure 12A It is a flowchart of the gas concentration sensing method according to the fourth embodiment of the present invention;

[0029] Figure 12B It is a detailed flowchart of step S104; and

[0030] Figure 13 It is a flowchart of establishing a standard curve of the target gas concentration conversion function.

[0031] Symbol Explanation

[0032] 100, 200... Gas sensing device

[0033] 10... Heater

[0034] 101... Surface

[0035] 20... Dielectric layer

[0036] 201... Carrying side

[0037] 30... Reference sensing element part, first reference sensing element part

[0038] 301…First sensing layer

[0039] 303…First conductive layer

[0040] 40…Target sensing material part, first target sensing material part

[0041] 401…Second sensing layer

[0042] 403…Second conductive layer

[0043] 50…Second reference sensing material part

[0044] 501…Third sensing layer

[0045] 503…Third conductive layer

[0046] 60…Second target sensing material part

[0047] 601…Fourth sensing layer

[0048] 603…Fourth conductive layer

[0049] 70, 70’…Controller

[0050] A1, B1…Admittance value acquisition stage

[0051] A3, B3…Partition calculation stage

[0052] A5, B5…Partition comparison stage

[0053] A7, B7…Concentration estimation stage Detailed implementation manners

[0054] The present invention will be described in detail in the following implementation manners. The content is sufficient to enable any person skilled in the relevant art to understand the technical content of the present invention and implement it accordingly. And according to the content disclosed in this specification, claims and drawings, any person skilled in the relevant art can easily understand the present invention. The following embodiments and implementation manners further illustrate the viewpoints of the present invention, but do not limit the scope of the present invention in any way.

[0055] The present invention provides a gas sensing device and a gas concentration sensing method. First, the first embodiment of the gas sensing device will be described below, and then two implementation manners of the gas concentration sensing method applicable to the first embodiment of the gas sensing device will be described; then the second embodiment of the gas sensing device will be described, and then four implementation manners of the gas concentration sensing method applicable to the second embodiment of the gas sensing device will be described.

[0056] Please refer to Figure 1, which shows the architecture diagram of the gas sensing device 100 according to the first embodiment of the present invention. The gas sensing device 100 is applicable to sense the concentration of a target gas in the gas to be measured. The gas sensing device 100 includes a heater 10, a dielectric layer 20, a reference sensing element part 30, a target sensing element part 40, and a controller 70. Please refer to Figure 2 , which shows a side view of elements such as the heater 10, the dielectric layer 20, the reference sensing element part 30, and the target sensing element part 40.

[0057] The heater 10 can receive power from an external power source (not shown) through the controller 70, for example. The heater 10 generates heat energy on the surface 101. For example, the heater 10 has a single heating element to heat the reference sensing element part 30 and the target sensing element part 40 together. As another example, the heater 10 has a plurality of heating elements to heat the reference sensing element part 30 and the target sensing element part 40 respectively. The purpose of setting the heater 10 is to heat the reference sensing element part 30 and the target sensing element part 40 to the same temperature simultaneously. As long as this purpose can be achieved, the present invention does not limit the number of heating elements in the heater 10. In addition, when the sensing materials used in the reference sensing element part 30 and the target sensing element part do not need to be heated (in other words, the target gas in the gas to be measured can be sensed at room temperature, or the ambient temperature has reached the working temperature of the sensing material), the setting of the heater 10 can also be omitted. The present invention does not limit whether to set the heater 10.

[0058] The dielectric layer 20 is disposed on the surface 101 of the heater 10. The dielectric layer 20 has a bearing side 201. The bearing side 201 preferably faces away from the surface 101 of the heater 10. Both the reference sensing element part 30 and the target sensing element part 40 are disposed on the bearing side 201.

[0059] The reference sensing element part 30 includes a first sensing layer 301 and a first conductive layer 303. The first sensing layer 301 is a metal oxide and has low sensitivity to the target gas. The first conductive layer 303 is connected to the first sensing layer 301 such that the current conducted by the first conductive layer 303 passes through the first sensing layer 301. Therefore, the controller 70 can detect the immittance value of the first conductive layer 303. Hereinafter, this immittance value is referred to as the measured reference immittance value, such as the resistance value or conductance value of direct current power. However, in each of the embodiments described later, the resistance value is taken as an example for illustration. The purpose of setting the reference sensing element part 30 is to reflect the degree of variation of the current environment (such as humidity in the air) for subsequent correction of the influence of environmental factors on the detected immittance value of the metal oxide.

[0060] The target sensing component 40 includes a second sensing layer 401 and a second conductive layer 403. The second sensing layer 401 is a metal oxide and has a high sensitivity to the target gas. The second conductive layer 403 is connected to the second sensing layer 401 such that the current conducted by the second conductive layer 403 passes through the second sensing layer 401. Therefore, the controller 70 can detect the impedance value of the second conductive layer 403, which is hereinafter referred to as the measured target impedance value. Similarly, in each of the embodiments described hereinafter, the resistance value is taken as an example for illustration. The purpose of providing the target sensing component 40 is to detect its impedance value when the metal oxide of the target sensing component 40 contacts the gas to be measured, so as to sense the concentration of the target gas therein. In addition, this gas sensing device 100 may also include another target sensing component for use as a backup when the target sensing component 40 is damaged. In this setting, the heating operations of the heater 10 for these two target sensing components are not related and can be heated individually at different times.

[0061] The definition of "low sensitivity" described herein is that the sensitivity of the reference sensing component 30 to the target gas is lower than the sensitivity of the target sensing component 40 to the target gas. To make the sensitivity of the sensing material to the target gas high or low, the method of doping with specific metals can be adopted. For example, the sensing materials of tungsten trioxide (WO3) and tin dioxide (SnO2) can be loaded on the bearing side 201 of the dielectric layer 20. The loading method is drop coating or sputtering deposition. The part of the bearing side 201 loaded with tungsten trioxide can be used as the first sensing layer 301 of the reference sensing component 30, where the particle size of the sensing material is 30 nanometers and the thickness is 0.1 micrometer. The part of the bearing side 201 loaded with tin dioxide can be used as the second sensing layer 401 of the target sensing component 40, where the particle size of the sensing material is 7 to 10 nanometers and the thickness is 1 micrometer. The present invention does not limit the areas of the first sensing layer 301 and the second sensing layer 401 and the types of sensing materials loaded, nor does it limit the areas and thicknesses of the first conductive layer 303 and the second conductive layer 403. It should be noted that the greater the difference in the sensitivity to the target gas between the one with low sensitivity and the one with high sensitivity described herein, the better, that is, the lower the sensitivity of the reference sensing component 30 to the target gas, the better, and it is best to be insensitive; on the other hand, the higher the sensitivity of the target sensing component 40 to the target gas, the better.

[0062] Please refer to Figure 1。The controller 70 is electrically connected to the heater 10, the reference sensing element portion 30, and the target sensing element portion 40. For example, the controller 70 includes a heating driver (not shown) for driving one or more heating elements in the heater 10. When the heater 10 heats the reference sensing element portion 30 and the target sensing element portion 40 and introduces the gas to be measured into the gas sensing device 100, the controller 70 detects the measured reference impedance value of the reference sensing element portion 30 and the measured target impedance value of the target sensing element portion 40. In addition, the controller 70 is used to obtain at least one of a plurality of pre-stored data. Therefore, the controller 70 can calculate the target gas concentration value in the gas to be measured based on the measured reference impedance value, the measured target impedance value, and the pre-stored data.

[0063] Regarding the storage of the pre-stored data, for example, the existing storage element of the controller 70 itself can be used. For another example, a storage device located outside the controller 70 can be used. The storage device is communicatively connected to the controller 70 to facilitate the controller 70 to obtain the pre-stored data.

[0064] The pre-stored data includes: a plurality of original reference resistance values (original reference impedance values) associated with the reference sensing element portion 30, a plurality of original target resistance values (original target impedance values) associated with the target sensing element portion 40, a plurality of specified concentration values, a plurality of relationship functions associated with the reference sensing element portion 30 and the target sensing element portion 40, and at least one target gas concentration conversion function. Regarding the specific content of each of the pre-stored data, it will be described together when describing the implementation manner of the gas concentration sensing method of the present invention below.

[0065] Please refer to Figure 3A , which shows a flowchart of the gas concentration sensing method according to the first embodiment of the present invention. The gas concentration sensing method is applicable to the gas sensing device 100 capable of sensing the target gas as described in this embodiment, which includes a heater 10, a reference sensing element portion 30 with low sensitivity to the target gas, a target sensing element portion 40 with high sensitivity to the target gas, and a controller 70. Note that in the following steps, although the electrical values obtained by the reference sensing element portion 30 and the target sensing element portion 40 are only taken as resistance values, they can also be other types of impedance values, and the present case is not limited thereto.

[0066] Please refer to step S31. The heater 10 generates heat energy to raise the temperatures of the reference sensing element portion 30 and the target sensing element portion 40 and bring them into contact with the gas to be measured.

[0067] Please refer to step S32. When the temperatures of the reference sensing element portion 30 and the target sensing element portion 40 rise and the reference sensing element portion 30 and the target sensing element portion 40 are in contact with the gas to be measured, the controller 70 detects the impedance values of the reference sensing element portion 30 and the target sensing element portion 40, that is, the measured reference resistance value R of the reference sensing element portion 30 ref(Measured reference impedance value) and the measured target resistance value R of the target sensing part 40 sen (Measured target impedance value). For example, the controller 70 can detect the measured reference resistance value R of the first sensing layer 301 through the first conductive layer 303 ref , and detect the measured target resistance value R of the second sensing layer 401 through the second conductive layer 403 sen .

[0068] Please refer to step S33. The controller 70 calculates the reference coefficient of variation α based on the measured reference resistance value R ref and the original reference resistance value R ref 0 (original reference impedance value). The original reference resistance value R ref 0 is associated with the reference sensing part 30. For example, before the gas sensing device 100 leaves the factory, a target gas with a specified concentration (such as 0 ppm) is brought into contact with the heated reference sensing part 30. At this time, the controller 70 detects the resistance value (impedance value) of the reference sensing part 30, and uses this resistance value as the original reference resistance value R ref 0, which is stored in the existing storage element or storage device of the controller 70 itself. For example, the reference coefficient of variation α is the ratio (or difference) of the measured reference resistance value R ref and the original reference resistance value R ref 0, as shown in Equation 1. The reference coefficient of variation α is used to reflect the influence degree of the current environmental change (such as unstable oxygen adsorption or changes in temperature, humidity, etc.) on the reference sensing part 30.

[0069] α = R ref / R ref 0 (Equation 1)

[0070] Please refer to step S34. The controller 70 calculates the target gas concentration value based on the reference coefficient of variation α, the relationship function F, the measured target resistance value R sen and the target gas concentration conversion function. The relationship function F is the correlation between the reference sensing part 30 and the target sensing part 40. For example, the relationship function F is the dependence relationship between the measured reference resistance value R ref and the measured target resistance value R sen . For another example, the relationship function F is the dependence relationship between the variation rate of the measured reference resistance value R ref and the variation rate of the measured target resistance value R sen . The target gas concentration conversion function is used to convert a calibrated resistance value (calibrated impedance value) into a target gas concentration value.

[0071] Please refer to Figure 3B , which shows Figure 3AThe detailed process of step S34. Please refer to step S341, where the controller 70 calculates the target coefficient of variation β based on the reference coefficient of variation α and the relationship function F. For example, the controller 70 substitutes the reference coefficient of variation α into the relationship function F to obtain the target coefficient of variation β, as shown in Equation 2.

[0072] β = F(α) (Equation 2)

[0073] Please refer to step S343, where the controller 70 calculates the corrected resistance value R based on the measured target resistance value R sen and the target coefficient of variation β cal . For example, the controller 70 uses the quotient of the measured target resistance value R sen divided by the target coefficient of variation β as the corrected resistance value R cal , as shown in Equation 3.

[0074] R cal = R sen / β (Equation 3)

[0075] Please refer to step S345, where the controller 70 substitutes the corrected resistance value R cal into the target gas concentration conversion function to obtain the target gas concentration value.

[0076] Please refer to Figure 4 , which shows a flowchart of the gas concentration sensing method applicable to the second embodiment of the present invention. The gas concentration sensing method is applicable to the gas sensing device 100 capable of sensing the target gas as described in the first embodiment, which includes a heater 10, a reference sensing element part 30 with low sensitivity to the target gas, a target sensing element part 40 with high sensitivity to the target gas, and a controller 70.

[0077] Please refer to Figure 4 . Basically, this embodiment mainly includes an impedance value acquisition stage A1, a partition calculation stage A3, a partition comparison stage A5, and a concentration estimation stage A7. In the impedance value acquisition stage A1, the controller 70 can detect a measured reference impedance value of the reference sensing element part 30 and a measured target impedance value of the target sensing element part 40. In the partition calculation stage A3, the controller 70 calculates multiple predicted target impedance values based on the measured reference impedance value and multiple relationship functions, where these relationship functions and these predicted target impedance values correspond to multiple specified concentration values. In the partition comparison stage A5, the controller 70 compares the measured target impedance value with these predicted target impedance values to select one of these specified concentration values. In the concentration estimation stage A7, the controller 70 estimates the target gas concentration value based on one of multiple target coefficients of variation and the measured target impedance value.

[0078] Please refer to Figure 5A and Figure 5B, which shows a detailed flowchart of the gas concentration sensing method according to the second embodiment of the present invention. Figure 5A Steps S41 to S42 belong to the aforementioned impedance value-taking stage A1, steps S43, S441 and S443 belong to the aforementioned partition calculation stage A3, step S445 belongs to the aforementioned partition comparison stage A5, and steps S447 and S449 belong to the aforementioned concentration calculation stage A7.

[0079] Figure 5A Steps S41 to S43 are substantially the same as steps S31 to S33 in FIG. 3. Briefly, the controller 70 detects the measured reference resistance value R ref (measured reference impedance value) and the measured target resistance value R sen (measured target impedance value) of the target sensing element 40. Briefly, it is the impedance value described in the impedance value-taking stage A1, and calculates the reference coefficient of variation α based on the measured reference resistance value R ref and the original reference resistance value R ref 0 (original reference impedance value).

[0080] Please refer to step S44. The controller 70 calculates the target gas concentration value based on the reference coefficient of variation α, a plurality of relationship functions F (k ppm) , a plurality of original target resistance values R sen 0,(k ppm) (original target impedance value), the measured target resistance value R sen and the target gas concentration conversion function. The number of the relationship functions F (k ppm) and the original target resistance values R sen 0,(k ppm) is determined by the number of specified concentration values. For example, if the specified concentration values (in parts per million, ppm) are preset to 4: 0 ppm, 20 ppm, 100 ppm, and 200 ppm, then the corresponding relationship functions F (k ppm) are 4: F (0ppm) , F (20ppm) , F (100ppm) and F (200ppm) ; the corresponding original target resistance values R sen 0,(k ppm) are also 4: R sen 0,(0ppm) , R sen 0,(20ppm) , R sen 0,(100ppm) and R sen0,(200ppm) 。The relationship function F (k ppm) for each of them is the correlation between the reference sensing element part 30 and the target sensing element part 40 under target gases of different concentrations. These relationship functions F (k ppm) each correspond to a preset specified concentration value. For example, the relationship function F (k ppm) is to measure the reference resistance value R ref and the measured target resistance value R sen under target gases of various concentrations. Take another example, the relationship function F (k ppm) is to measure the variation rate of the reference resistance value R ref and the variation rate of the measured target resistance value R sen under target gases of various concentrations. Regarding multiple original target resistance values R sen 0,(k ppm) , for example, before the gas sensing device 100 leaves the factory, target gases of multiple specified concentrations (such as: 0 ppm, 20 ppm, 100 ppm, 200 ppm) are respectively brought into contact with the heated target sensing element part 40, and the controller 70 detects the resistance values (or impedance values, such as: R sen 0,(0ppm) , R sen 0,(20ppm) , R sen 0,(100ppm) and R sen 0,(200ppm) ) of the target sensing element part 40 at these specified concentrations, and uses these resistance values as the multiple original target resistance values R sen 0,(k ppm) , and stores them in the storage element or storage device already existing in the controller 70 itself.

[0081] Please refer to Figure 5B , which shows Figure 5A the detailed process of step S44 in (k ppm) Calculate multiple target variation coefficients β (k ppm) according to the reference variation coefficient α and multiple relationship functions F (k ppm) . The number of the target variation coefficients β (k ppm) is determined by the number of specified concentration values. Continuing with the previous example, the controller 70 substitutes the reference variation coefficient α into 4 relationship functions F (k ppm), which includes β (0ppm) , β (20ppm) , β (100ppm) , and β (200ppm) , as shown in the following formulas 4, 5, 6, and 7.

[0082] β (0ppm) = F (0ppm) (α) (Formula 4)

[0083] β (20ppm) = F (20ppm) (α) (Formula 5)

[0084] β (100ppm) = F (200ppm) (α) (Formula 6)

[0085] β (100ppm) = F (200ppm) (α) (Formula 7)

[0086] Please refer to step S443. The controller 70 calculates multiple predicted target resistance values R sen 0,(k ppm) and multiple target coefficient of variation β (k ppm) to calculate multiple predicted target resistance values R sen,pre,(k ppm) (predicted target impedance value, i.e., multiple partition reference values described in the partition calculation stage A3). Regarding the calculation method of step S443, taking the previous example, for multiple specified concentrations (such as 0 ppm, 20 ppm, 100 ppm, 200 ppm), the product of the original target resistance value R sen 0,(k ppm) corresponding to the same specified concentration and the target coefficient of variation β (k ppm) is used as the predicted target resistance value R sen,pre,(k ppm) , which includes R sen,pre,(0ppm) , R sen,pre,(20ppm) , R sen,pre,(100ppm) , and R sen,pre,(200ppm) , as shown in the following formulas 8, 9, 10, and 11.

[0087] R sen,pre,(0ppm) = R sen 0,(0ppm) ×β (0ppm) (Formula 8)

[0088] R sen,pre,(20ppm) = R sen 0,(20ppm) ×β (20ppm) (Formula 9)

[0089] Rsen,pre,(100ppm) =R sen 0,(100ppm) ×β (100ppm) (Equation 10)

[0090] R sen,pre,(200ppm) =R sen 0,(200ppm) ×β (200ppm) (Equation 11)

[0091] Please refer to step S445. The controller 70 determines one from multiple predicted target resistance values R sen from multiple predicted target resistance values R sen,pre,(k ppm) For example, the controller 70 calculates the difference between the measured target resistance value R sen and multiple predicted target resistance values R sen,pre,(k ppm) and selects the predicted target resistance value R corresponding to the minimum of these differences (or the minimum of the absolute values of these differences) sen,pre,(x ppm ) .

[0092] Please refer to step S447. The controller 70 calculates the corrected resistance value R sen and the target coefficient of variation β (x ppm) where the target coefficient of variation β cal (corrected impedance value), and the target coefficient of variation β (x ppm) is one of the aforementioned target coefficients of variation β (k ppm) and the specified concentration corresponding to the target coefficient of variation β (x ppm) is the same as the specified concentration corresponding to the predicted target resistance value R determined in step S445 sen,pre,(x ppm) Regarding the calculation method of the corrected resistance value R cal For example, the controller 70 uses the measured target resistance value R sen divided by the target coefficient of variation β (x ppm) and takes the quotient as the corrected resistance value R cal , as shown in Equation 12

[0093] R cal = R sen / β (x ppm) (Equation 12)

[0094] Please refer to step S449. The controller 70 substitutes the corrected resistance value R cal into the target gas concentration conversion function to obtain the target gas concentration value

[0095] Please refer to Figure 6 which shows the architecture diagram of the gas sensing device 200 according to the second embodiment of the present invention. The reference sensing element part 30 and the target sensing element part 40 in the gas sensing device 100 of the foregoing first embodiment are respectively referred to as the first reference sensing element part 30 and the first target sensing element part 40 in the second embodiment. The gas sensing device 200 of the second embodiment further includes a second reference sensing element part 50 and a second target sensing element part 60. The controller 70' of the second embodiment is also electrically connected to the second reference sensing element part 50 and the second target sensing element part 60. The second target sensing element part 60 can be used as a backup sensing element for the first target sensing element part 40. Therefore, when describing the gas concentration sensing method of the second embodiment applicable to the gas sensing device 200 hereinafter, the implementation manner of the second target sensing element part 60 will not be repeated.

[0096] Specifically, the gas sensing device 200 is applicable to sensing the concentration of a target gas in a gas to be measured. The gas sensing device 200 includes a heater 10, a dielectric layer 20, a first reference sensing element part 30, a first target sensing element part 40, a second reference sensing element part 50, a second target sensing element part 60, and a controller 70'. Please refer to Figure 7 which shows a side view of elements such as the heater 10, the dielectric layer 20, the first reference sensing element part 30, the first target sensing element part 40, the second reference sensing element part 50, and the second target sensing element part 60.

[0097] The heater 10 can receive power from an external power source (not shown) through the controller 70' for example. The heater 10 generates heat energy on the surface 101. For example, the heater 10 has a single heating element to heat the first reference sensing element part 30, the first target sensing element part 40, and the second reference sensing element part 50, and uses this heating unit or preferably another heating unit to heat the second target sensing element part 60. As another example, the heater 10 has a plurality of heating elements to heat the first reference sensing element part 30, the first target sensing element part 40, the second reference sensing element part 50, and the second target sensing element part 60 respectively. The purpose of providing the heater 10 is to heat the first reference sensing element part 30, the first target sensing element part 40, and the second reference sensing element part 50 to the same temperature simultaneously, and preferably can independently heat the second target sensing element part 60 to this temperature. As long as this purpose can be achieved, the present invention does not limit the number of heating elements in the heater 10.

[0098] The dielectric layer 20 is disposed on the surface 101 of the heater 10. The dielectric layer 20 has a bearing side 201. The bearing side 201 preferably faces away from the surface 101 of the heater 10. The first reference sensing element part 30, the first target sensing element part 40, the second reference sensing element part 50, and the second target sensing element part 60 are all disposed on the bearing side 201.

[0099] In the second embodiment, the first reference sensing element portion 30 is the same as the reference sensing element portion 30 in the first embodiment, and the first target sensing element portion 40 is the same as the target sensing element portion in the first embodiment, and thus will not be described repeatedly herein. The measured reference impedance value and the measured target impedance value described in the first embodiment are respectively referred to as the first measured reference impedance value and the first measured target impedance value in this embodiment.

[0100] The second reference sensing element portion 50 includes a third sensing layer 501 and a third conductive layer 503. The third sensing layer 501 is a metal oxide and is sensitive to the target gas. The third conductive layer 503 is connected to the third sensing layer 501 such that the current conducted by the third conductive layer 503 passes through the third sensing layer 501. Therefore, the controller 70' can detect the impedance value of the third conductive layer 503, which is hereinafter referred to as the second measured reference impedance value. However, the resistance value is taken as an example in each of the embodiments described hereinafter. The second reference sensing element portion 50 can be used to reflect the variation degree of the sensing material (i.e., the first sensing layer 301) of the first target sensing element portion 40.

[0101] The second target sensing element portion 60 includes a fourth sensing layer 601 and a fourth conductive layer 603. The fourth sensing layer 601 is a metal oxide and is sensitive to the target gas. The fourth conductive layer 603 is connected to the fourth sensing layer 601 such that the current conducted by the fourth conductive layer 603 passes through the fourth sensing layer 601. Therefore, the controller 70' can detect the impedance value of the fourth conductive layer 603, which is hereinafter referred to as the second measured target impedance value. Similarly, the resistance value is taken as an example in each of the embodiments described hereinafter. The second target sensing element portion 60 is provided as a backup for the first target sensing element portion 40. For example, when the controller 70' determines that the first target sensing element portion 40 is abnormal, the controller 70' can instead detect the impedance value of the second target sensing element portion 60 when it contacts the gas to be measured to calculate the concentration of the target gas in the gas to be measured, or after the heater 10 heats the second target sensing element portion 60 to the same temperature as the first and second reference sensing element portions 30 and 50, then the controller 70' detects the impedance value of the second target sensing element portion 60. In other embodiments, the second target sensing element portion 60 may not be provided or multiple second target sensing element portions may be provided. The present invention does not limit the number of the second target sensing element portions 60 provided.

[0102] The sensitivity of the first reference sensing material part 30 to the target gas is lower than that of the first target sensing material part 40, the second reference sensing material part 50, and the second target sensing material part 60 to the target gas. To make the sensitivity of the sensing material to the target gas high or low, doping with specific metals can be adopted. For example, the sensing materials of tungsten trioxide (WO3) and tin dioxide (SnO2) are loaded onto the bearing side 201 of the dielectric layer 20. The loading method is dropcoating or sputtering deposition. The part of the bearing side 201 loaded with tungsten trioxide can serve as the first sensing layer 301 of the first reference sensing material part 30, where the particle size of the sensing material is 30 nanometers and the thickness is 0.1 micrometer. The part of the bearing side 201 loaded with tin dioxide can serve as the second sensing layer 401 of the first target sensing material part 40, the third sensing layer 501 of the second reference sensing material part 50, and the fourth sensing layer 601 of the second target sensing material part 60. Among them, the particle size of the sensing material in the second sensing layer 401 is 7 to 10 nanometers and the thickness is 1 micrometer; the particle size of the sensing material in the third sensing layer 501 is 7 to 10 nanometers and the thickness is 2.5 micrometers; the particle size of the sensing material in the fourth sensing layer 601 is 7 to 10 nanometers and the thickness is 3 micrometers. The present invention does not limit the areas of the first sensing layer 301, the second sensing layer 401, the third sensing layer 501, and the fourth sensing layer 601, nor the types of sensing materials loaded, nor the areas and thicknesses of the first conductive layer 303, the second conductive layer 403, the third conductive layer 503, and the fourth conductive layer 603. It should be noted that for the first target sensing material part 40, the second reference sensing material part 50, and the second target sensing material part 60, the greater the difference in sensitivity to the target gas from the first reference sensing material part 30, the better. That is, the lower the sensitivity of the first reference sensing material part 30 to the target gas, the better, and being insensitive is the best. On the other hand, for the first target sensing material part 40, the second reference sensing material part 50, and the second target sensing material part 60, the higher the sensitivity to the target gas, the better.

[0103] Please refer to Figure 6。The controller 70’ is electrically connected to the heater 10, the first reference sensing element portion 30, the first target sensing element portion 40, the second reference sensing element portion 50, and the second target sensing element portion 60. For example, the controller 70’ includes a heating driver (not shown) for driving one or more heaters in the heater 10. When the heater 10 heats the first reference sensing element portion 30, the first target sensing element portion 40, and the second reference sensing element portion 50 (and can also heat the second target sensing element portion 60 simultaneously) and introduces the gas to be measured into the gas sensing device 200, the controller 70’ detects the first measured reference impedance value of the first reference sensing element portion 30, the first measured target impedance value of the first target sensing element portion 40, and the second measured reference impedance value of the second reference sensing element portion 50 (or also includes the second measured target impedance value of the second target sensing element portion 60). In addition, the controller 70’ is used to obtain at least one from a plurality of pre-stored data. Therefore, the controller 70’ can calculate the concentration of the target gas in the gas to be measured based on the first measured reference impedance value, the first measured target impedance value, the second measured reference impedance value (and the second measured target impedance value), etc., and the pre-stored data.

[0104] Regarding the storage of the pre-stored data, for example, the existing storage element of the controller 70’ itself can be used. For another example, a storage device located outside the controller 70’ can be used. The storage device is communicatively connected to the controller 70’ so that the controller 70’ can obtain the pre-stored data.

[0105] The pre-stored data includes: a plurality of original reference resistance values (impedance values), a plurality of original target resistance values (impedance values), a plurality of specified concentration values, a plurality of relationship functions, and at least one target gas concentration conversion function. Regarding the specific content of each of the pre-stored data, it will be described together when describing the embodiments of the gas concentration sensing method of the present invention below.

[0106] Please refer to Figure 8 , which shows a flowchart of the gas concentration sensing method applicable to the second embodiment of the present invention. The gas concentration sensing method is applicable to the gas sensing device 200 that can sense the target gas as described in the second embodiment, which includes a heater 10, a first reference sensing element portion 30 with low sensitivity to the target gas, a target sensing element portion 40 with high sensitivity to the target gas (i.e., the first target sensing element portion 40 described above), a second reference sensing element portion 50 with high sensitivity to the target gas, and a controller 70’.

[0107] Please refer to Figure 8 , the following describes four implementation manners of the gas concentration sensing method applicable to the second embodiment of the gas sensing device. Basically, similar to the second implementation manner of the foregoing first embodiment, the four implementation manners described below mainly all include Figure 8The impedance value acquisition stage B1, the partition calculation stage B3, the partition comparison stage B5, and the concentration calculation stage B7 are shown. In the impedance value acquisition stage B1, when the reference sensing element part 30 and the target sensing element part 40 contact the gas to be measured, the controller 70' can detect a first measured reference impedance value of the first reference sensing element part 30, a measured target impedance value of the target sensing element part 40, and a second measured reference impedance value of the second reference sensing element part 50. In the partition calculation stage B3, the controller 70' calculates a plurality of partition reference values based on at least one of the first measured reference impedance value and the second measured reference impedance value and a plurality of relationship functions, where these relationship functions and these partition reference values all correspond to a plurality of specified concentration values. In the partition comparison stage B5, the controller 70 compares the above-mentioned partition reference values with a comparison reference value, and then determines which partition of the specified concentration value the comparison reference value belongs to, that is, selects one of these specified concentration values. In the concentration calculation stage B7, the controller 70' calculates a target gas concentration value based on a target coefficient of variation and the measured target impedance value, that is, calculates the concentration of the target gas in the gas to be measured, where the target coefficient of variation corresponds to the one of the above-mentioned specified concentration values.

[0108] Please refer to Figure 9A and Figure 9B , which shows the detailed flowchart of the gas concentration sensing method according to the first embodiment of the present invention. Figure 9A The steps S71 to S72 belong to the aforementioned impedance value acquisition stage B1, the steps S73, S741 and S743 belong to the aforementioned partition calculation stage B3, the step S745 belongs to the aforementioned partition comparison stage B5, and the steps S747 and S749 belong to the concentration calculation stage B7.

[0109] Please refer to step S71. The heater 10 generates heat energy to raise the temperatures of the first reference sensing element part 30, the target sensing element part 40, and the second reference sensing element part 50 and contact the gas to be measured.

[0110] Please refer to step S72. When the temperatures of the first reference sensing element part 30, the target sensing element part 40, and the second reference sensing element part 50 rise and the first reference sensing element part 30, the target sensing element part 40, and the second reference sensing element part 50 contact the gas to be measured, the controller 70' detects the first measured reference resistance value R ref1 (the first measured reference impedance value) of the first reference sensing element part 30, the measured target resistance value R sen (the measured target impedance value) of the target sensing element part 40, and the second measured reference resistance value R ref2 (the second measured reference impedance value) of the second target sensing element part 50. In short, the first measured reference resistance value R ref1 , the measured target resistance value R sen , and the second measured reference resistance value R ref2That is, the impedance value described in the impedance acquisition stage B1. For example, the controller 70' can detect the first measured reference resistance value R of the first sensing layer 301 through the first conductive layer 303 ref1 , detect the measured target resistance value R of the second sensing layer 401 through the second conductive layer 403 sen , detect the second measured reference resistance value R of the third sensing layer 401 through the third conductive layer 503 sen2 .

[0111] Please refer to step S73. The controller 70' calculates the first reference coefficient of variation α based on the first measured reference resistance value R ref1 and the first original reference resistance value R ref1,0 (the first original reference impedance value). The first original reference resistance value R ref1,0 is associated with the first reference sensing part 30. For example, before the gas sensing device 200 leaves the factory, the target gas with a specified concentration (such as 0 ppm) contacts the heated first reference sensing part 30. At this time, the controller 70' detects the resistance value of the first reference sensing part 30 and uses this resistance value as the first original reference resistance value R ref1,0 , which is stored in the existing storage element or storage device of the controller 70' itself. For example, the first reference coefficient of variation α is the ratio of the first measured reference resistance value R ref1 and the first original reference resistance value R ref1,0 , as shown in Equation 13. The first reference coefficient of variation α is used to reflect the influence degree of the current environmental change (such as unstable oxygen adsorption or changes in temperature and humidity) on the first reference sensing part 30

[0112] α = R ref1 / R ref1,0 (Equation 13)

[0113] Please refer to step S74. The controller 70' calculates the target gas concentration value based on the first reference coefficient of variation α, multiple first relationship functions F 1(k ppm) , multiple second original reference resistance values R ref2,0,(k ppm) (the second original reference impedance value), the measured target resistance value R sen , the second measured reference resistance value R ref2 (the second measured reference impedance value), multiple second relationship functions F 2(k ppm) and the target gas concentration conversion function

[0114] The first relationship function F 1(k ppm) , the second original reference resistance value R ref2,0,(k ppm) and the second relationship function F2(k ppm) The quantity is determined by the quantity of the specified concentration values. For example, if the specified concentration values are preset to 4: 0 ppm, 20 ppm, 100 ppm, and 200 ppm, then the corresponding first relationship functions are 4: F 1(0ppm) 、F 1(20ppm) 、F 1(100ppm) and F 1(200ppm) ; the corresponding second original reference resistance values are 4: R ref2,0,(0ppm) 、R ref2,0,(20ppm) 、R ref2,0,(100ppm) and R ref2,0,(200ppm) ; the corresponding second relationship functions are 4: F 2(0ppm) 、F 2(20ppm) 、F 2(100ppm) and F 2(200ppm) . Based on the conditions of the target gas at each specified concentration value, each of the first relationship functions F 1(k ppm) is the correlation between the first reference sensing part 30 and the second reference sensing part 50. For example, the first relationship function F 1(k ppm) is the dependency relationship between the first measured reference resistance value R ref1 and the second measured reference resistance value R ref2 . To give another example, the first relationship function F 1(k ppm) is the dependency relationship between the variation rate of the first measured reference resistance value R ref1 and the variation rate of the second measured reference resistance value R ref2 . Regarding the multiple second original reference resistance values R ref2,0,(k ppm) , for example, before the gas sensing device 200 leaves the factory, target gases with multiple specified concentrations (such as: 0 ppm, 20 ppm, 100 ppm, 200 ppm) are respectively brought into contact with the heated second reference sensing part 50, and the controller 70'detects the resistance values of the second reference sensing part 50 at these specified concentrations (such as: R ref2,0,(0ppm) 、R ref2,0,(20ppm) 、R ref2,0,(100ppm) and R ref2,0,(200ppm) ), and uses these resistance values as the multiple second original reference resistance values R ref2,0,(k ppm) , which are stored in the existing storage element or storage device of the controller 70'itself. Based on the conditions of the target gas at each specified concentration value, each of the second relationship functions F 2(k ppm) is the correlation between the second reference sensing part 50 and the target sensing part 40. For example, the second relationship function F 2(k ppm) is the second measured reference resistance value Rref2 and the dependency relationship of the measured target resistance value R sen For another example, the second relationship function F 2(k ppm) is the second measured reference resistance value R ref2 variation rate and the dependency relationship of the measured target resistance value R sen variation rate.

[0115] Please refer to Figure 9B which shows Figure 9A the detailed process of step S74 in Figure 8 where step S741 and step S743 belong to Figure 8 the partition calculation stage B3 of Figure 8 and step S744 belongs to

[0116] Please refer to step S741. The controller 70' calculates multiple second reference variation coefficients γ 1(k ppm) based on the first reference variation coefficient α and multiple first relationship functions F (k ppm) . The number of the second reference variation coefficients γ (k ppm) is determined by the number of the first relationship functions F 1(k ppm) . Continuing with the previous example, the controller 70' substitutes the reference variation coefficient α into 4 first relationship functions F 1(k ppm) to obtain 4 second reference variation coefficients γ (k ppm) which include γ (0ppm) 、γ (20ppm) 、γ (100ppm) and γ (200ppm) as shown in the following equations 14, 15, 16 and 17.

[0117] γ (0ppm) =F 1(0ppm) (α) (Equation 14)

[0118] γ (20ppm) =F 1(20ppm) (α) (Equation 15)

[0119] γ (100ppm) =F 1(200ppm) (α) (Equation 16)

[0120] γ (100ppm) =F 1(200ppm) (α) (Equation 17)

[0121] Please refer to step S743, where the controller 70' calculates multiple second predicted reference resistance values R ref2,0,(k ppm) and multiple second reference coefficient of variation γ (k ppm) to calculate multiple second predicted reference resistance values R ref2,pre,(k ppm) (the second predicted reference impedance value, i.e., the multiple partition reference values described in partition calculation stage B3). Regarding the calculation method of step S743, taking the previous example, for multiple specified concentrations (e.g., 0 ppm, 20 ppm, 100 ppm, 200 ppm), the product of the second original reference resistance value R ref2,0,(k ppm) corresponding to the same specified concentration and the second reference coefficient of variation γ (k ppm) is used as the second predicted reference resistance value R ref2,pre,(kppm) (e.g., R ref2,pre,(0ppm) , R ref2,pre,(20ppm) , R ref2,pre,(100ppm) , and R ref2,pre,(200ppm) ), as shown in the following equations 18, 19, 20 and 21.

[0122] R ref2,pre,(0ppm) = R ref2 0,(0ppm) ×γ (0ppm) (Equation 18)

[0123] R ref2,pre,(20ppm) = R ref2 0,(20ppm) ×γ (20ppm) (Equation 19)

[0124] R ref2,pre,(100ppm) = R ref2 0,(100ppm) ×γ (100ppm) (Equation 20)

[0125] R ref2,pre,(200ppm) = R ref2 0,(200ppm) ×γ (200ppm) (Equation 21)

[0126] Please refer to step S745, where the controller 70' selects one from multiple second predicted reference resistance values R ref2 (i.e., the comparison reference value described in partition comparison stage B5) according to the second measured reference resistance value R ref2,pre,(k ppm) . For example, the controller 70' calculates the second measured target resistance value R ref2 and multiple second predicted reference resistance values R ref2,pre,(k ppm)multiple differences, and select the second predicted reference resistance value R corresponding to the minimum of these differences (or the minimum of the absolute values of these differences) ref2,pre,(x ppm) .

[0127] Please refer to step S746. The controller 70' calculates the target coefficient of variation β based on the second measured reference resistance value R ref2 , the second original reference resistance value R ref2,0,(x ppm) and the second relationship function F 2(x ppm) . (x ppm) . The second original reference resistance value R ref2,0,(x ppm) , the second predicted reference resistance value R selected in step S745 ref2,pre,(x ppm) and the second relationship function F 2(x ppm) all correspond to the same concentration x. In other words, this target coefficient of variation β (x ppm) is used as a parameter in stage B7 of the concentration calculation. Regarding the calculation method of the target coefficient of variation β (xppm) , for example, the controller 70' substitutes the quotient of the second measured reference resistance value R ref2 divided by the second original reference resistance value R ref2,0,(x ppm) into the second relationship function to obtain the value of the target coefficient of variation β (x ppm) , as shown in Equation 22.

[0128] β (x ppm) = F 2(x ppm) (R ref2 / R ref2,0,(x ppm) ) (Equation 22)

[0129] Please refer to step S747. The controller 70' calculates the corrected resistance value R sen (corrected impedance value) based on the measured target resistance value R (x ppm) and the target coefficient of variation β cal . Regarding the calculation method of the corrected resistance value R cal , for example, the controller 70' takes the quotient of the measured target resistance value R sen divided by the target coefficient of variation β (x ppm) as the corrected resistance value R cal , as shown in Equation 23.

[0130] R cal = R sen / β (x ppm) (Equation 23)

[0131] Please refer to step S749, the controller 70' corrects the resistance value R cal Substitute it into the target gas concentration conversion function to obtain the target gas concentration value.

[0132] Please refer to Figure 10A and Figure 10B , which shows the detailed flowchart of the gas concentration sensing method according to the second embodiment of the present invention. Figure 10A Steps S81 - S82 of[]] belong to the aforementioned impedance value taking stage B1, steps S841 - S843 belong to the aforementioned partition calculation stage B3, step S845 belongs to the aforementioned partition comparison stage B5, and step S847 belongs to the aforementioned concentration estimation stage B7.

[0133] Figure 10A Steps S81 - S82 of[]] are basically the same as steps S71 - S72 in Figure 9. Briefly, the controller 70' detects the first measurement reference resistance value R ref1 (the first measurement reference impedance value), the measurement target resistance value R sen (the target measurement impedance value) of the target sensing part 40, and the second measurement reference resistance value R ref2 (the second measurement reference impedance value) of the second target sensing part 50.

[0134] Please refer to step S84, the controller 70' calculates the target gas concentration value based on the first measurement reference resistance value R ref1 , multiple first relationship functions F 1(k ppm) , multiple second original reference resistance values R ref2,0,(k ppm) (the second original reference impedance value), the measurement target resistance value R sen , the second measurement reference resistance value R ref2 , multiple second relationship functions F 2(kppm) and the target gas concentration conversion function.

[0135] Please refer to Figure 10B , which shows Figure 10A the detailed process of step S84 in[]. Please refer to step S841, the controller 70' calculates multiple second predicted reference resistance values R ref1 and multiple first relationship functions F 1(k ppm) based on the first measurement reference resistance value R ref2,pre,(k ppm)(The second predicted reference impedance value, i.e., the multiple partition reference values described in the partition calculation stage B3). The first relationship function F 1(k ppm) The number is determined by the number of specified concentration values. For example, if the specified concentration values are preset to 4: 0 ppm, 20 ppm, 100 ppm, and 200 ppm, then the corresponding first relationship functions are 4: F 1(0ppm) 、F 1(20ppm) 、F 1(100ppm) 、and F 1(200ppm) . Each of the first relationship functions F 1(k ppm) is the correlation between the first reference sensing part 30 and the second reference sensing part 50. For example, the first relationship function F 1(k ppm) is the dependency relationship between the first measured reference resistance value R ref1 and the second measured reference resistance value R ref2 . Regarding the calculation method of step S841, continuing with the previous example, the controller 70' substitutes the first measured reference resistance value R ref1 into the 4 first relationship functions F 1(k ppm) respectively to obtain 4 second predicted reference resistance values R ref2,pre,(k ppm) , which include R ref2,pre,(0ppm) 、R ref2,pre,(20ppm) 、R ref2,pre,(100ppm) 、and R ref2,pre,(200ppm) , as shown in the following formulas 24, 25, 26, and 27.

[0136] R ref2,pre,(0ppm) =F 1(0ppm) (R ref1 )(Formula 24)

[0137] R ref2,pre,(20ppm) =F 1(20ppm) (R ref1 )(Formula 25)

[0138] R ref2,pre,(100ppm) =F 1(100ppm) (R ref1 )(Formula 26)

[0139] R ref2,pre,(200ppm) =F 1(200ppm) (R ref1 )(Formula 27)

[0140] Please refer to step S843. The controller 70' selects from the multiple second predicted reference resistance values R ref2 (i.e., the comparison reference value described in the partition comparison stage B5) according to the second measured reference resistance value R ref2,pre,(k ppm)Select one from (the second predicted reference impedance value). For example, the controller 70' calculates the second measured target resistance value R ref2 and multiple second predicted reference resistance values R ref2,pre,(k ppm) to obtain multiple differences, and select the second predicted reference resistance value R ref2 ,pre,(x ppm) .

[0141] Please refer to step S845. The controller 70' calculates the target coefficient of variation β ref2 based on the second measured reference resistance value R ref2 ,0,(x ppm) , the second original reference resistance value R 2(x ppm) and the second relationship function F (x ppm) . The second original reference resistance value R ref2 ,0,(x ppm) , the second predicted reference resistance value R ref2 ,pre,(x ppm) selected in step S843, and the second relationship function F 2(x ppm) correspond to the same concentration x. In other words, this target coefficient of variation β (x ppm) is used as the parameter in the concentration calculation stage B7. Regarding the calculation method of the target coefficient of variation β (xppm) , for example, the controller 70' substitutes the quotient of the second measured reference resistance value R ref2 divided by the second original reference resistance value R ref2 ,0,(k ppm) into the second relationship function to obtain the value of the target coefficient of variation β (k ppm) , as shown in Equation 28.

[0142] β (x ppm) = F2 (x ppm) (R ref2 / R ref2 ,0, (x ppm) ) (Equation 28)

[0143] Please refer to step S847. The controller 70' calculates the corrected resistance value R sen based on the measured target resistance value R (x ppm) and the target coefficient of variation β cal(Calibrated impedance value). Regarding the calculation method of the calibrated resistance value R cal For example, the controller 70' measures the target resistance value R sen divided by the target coefficient of variation β (x ppm) and uses the quotient as the calibrated resistance value R cal , as shown in Equation 29.

[0144] R cal = R sen / β (x ppm) (Equation 29)

[0145] Please refer to step S849. The controller 70' substitutes the calibrated resistance value R cal into the target gas concentration conversion function to obtain the target gas concentration value.

[0146] Please refer to Figure 11A and Figure 11B , which shows the detailed flowchart of the gas concentration sensing method according to the third embodiment of the present invention. Figure 11A Steps S91 - S92 of Figure 8 belong to the aforementioned impedance value acquisition stage B1, steps S93, S941 belong to the aforementioned partition calculation stage B3, step S943 belongs to Figure 8 the partition comparison stage B5 of

[0147] Figure 11A Steps S91 - S93 of Figure 9A are basically the same as steps S71 - S73 of ref1 . Briefly, the controller 70' detects the first measured reference resistance value R sen (first measured reference impedance value), the measured target resistance value R ref2 (measured target impedance value) of the target sensing part 40, and the second measured reference resistance value R ref1 and the first original reference resistance value R ref1,0 to calculate the first reference coefficient of variation α.

[0148] Please refer to step S94. The controller 70' calculates based on the first reference coefficient of variation α, multiple first relationship functions F 1(k ppm) , multiple second original reference resistance values R ref2 ,0,(k ppm) (second original reference impedance value), the measured target resistance value R sen , the second measured reference resistance value Rref2 , multiple second relationship functions F 2(k ppm) and the target gas concentration conversion function to calculate the target gas concentration value.

[0149] Please refer to Figure 11B , which shows Figure 11A the detailed process of step S94 in ref2 , multiple second original reference resistances R ref2,0,(k ppm) and multiple first relationship functions F 1(k ppm) to calculate multiple first predicted coefficient of variations α (k ppm) (i.e., the multiple partition reference values described in the partition calculation stage B3). For example, if the specified concentration values are preset to 4: 0 ppm, 20 ppm, 100 ppm, and 200 ppm, based on these specified concentration values, the controller 70' divides the second measured reference resistance value R ref2 by the quotient of each second original reference resistance value R ref2,0,(k ppm) and substitutes the quotient values into each first relationship function F 1(k ppm) to obtain 4 first predicted coefficient of variations α (kppm) , which includes α (0ppm) , α (20ppm) , α (100ppm) and α (200ppm) , as shown in the following equations 30, 31, 32, and 33.

[0150] α (0ppm) = F 1(0ppm) (R ref2 / R ref2,0,(0ppm) ) (Equation 30)

[0151] α (20ppm) = F 1(20ppm) (R ref2 / R ref2,20,(20ppm) ) (Equation 31)

[0152] α (100ppm) = F 1(100ppm) (R ref2 / R ref2,100,(100ppm) ) (Equation 32)

[0153] α (200ppm) = F 1(200ppm) (R ref2 / R ref2,200,(200ppm) ) (Equation 33)

[0154] Please refer to step S943. The controller 70' selects one from multiple first predicted variation coefficients α based on the first reference variation coefficient α (i.e., the comparison reference value described in the partition comparison stage B5). (k ppm) For example, the controller 70' calculates multiple differences between the first reference variation coefficient α and the multiple first predicted variation coefficients α (k ppm) and selects the first predicted variation coefficient α corresponding to the minimum value among these differences (or the minimum value among the absolute values of these differences). (x ppm) And the designated concentration value x corresponding to this first predicted variation coefficient α (x ppm)

[0155] Please refer to step S945. The controller 70' calculates the target variation coefficient β (x ppm) based on the first predicted variation coefficient α 2(x ppm) and the second relationship function F (x ppm) . The first predicted variation coefficient α selected in step S943 (x ppm) and the second relationship function F 2(x ppm) correspond to the same concentration x. Regarding the calculation method of the target variation coefficient β (k ppm) , for example, based on the designated concentration x corresponding to the first predicted variation coefficient α selected in step S943 (k ppm) , the controller 70' selects one from the multiple quotient values calculated in step S941 and substitutes it into the second relationship function F with the corresponding designated concentration 2(k ppm) to obtain the target variation coefficient β (k ppm) as shown in Equation 34 below.

[0156] β (k ppm) = F 2(k ppm) (R ref2 / R ref2,0,(k ppm) )(Equation 34)

[0157] Please refer to step S947. The controller 70' calculates the corrected resistance value R sen based on the measured target resistance value R (k ppm) and the target variation coefficient β cal (corrected impedance value). Regarding the corrected resistance value R​cal The calculation method, for example, the controller 70' measures the target resistance value R sen and divides it by the target coefficient of variation β (k ppm) and takes the quotient value as the calibrated resistance value R cal , as shown in Equation 35.

[0158] R cal = R sen / β (k ppm) (Equation 35)

[0159] Please refer to step S949. The controller 70' substitutes the calibrated resistance value R cal into the target gas concentration conversion function to obtain the target gas concentration value.

[0160] Please refer to Figure 12A and 12B , which shows the detailed flowchart of the gas concentration sensing method according to the fourth embodiment of the present invention for sensing the concentration of the target gas in the gas to be measured. Figure 12A Steps S101 - S102 belong to the aforementioned impedance value acquisition stage B1, steps S103, S1041, and S1043 belong to the aforementioned partition calculation stage B3, step S1044 belongs to the aforementioned partition comparison stage B5, and step S1047 belongs to the aforementioned concentration estimation stage B7.

[0161] Please refer to step S101. The heater 10 generates heat energy to raise the temperatures of the first reference sensing part 30, the target sensing part 40, and the second reference sensing part 50 and bring them into contact with the gas to be measured.

[0162] Please refer to step S102. When the temperatures of the first reference sensing part 30, the target sensing part 40, and the second reference sensing part 50 rise and the first reference sensing part 30, the target sensing part 40, and the second reference sensing part 50 are in contact with the gas to be measured, the controller 70' detects the first measured reference resistance value R ref1 (the first measured reference impedance value) of the first reference sensing part 30, the measured target resistance value R sen (the measured target impedance value) of the target sensing part 40, and the second measured reference resistance value R ref2 (the second measured reference impedance value) of the second target sensing part 50. For example, the controller 70' can detect the first measured reference resistance value R ref1 of the first sensing layer 301 through the first conductive layer 303, detect the measured target resistance value R sen of the second sensing layer 401 through the second conductive layer 403, and detect the second measured reference resistance value R sen2 of the third sensing layer 401 through the third conductive layer 503.

[0163] Please refer to step S103, the controller 70' calculates the first reference coefficient of variation α based on the first measured reference resistance value R ref1 and the first original reference resistance value R ref1,0 (the first original reference impedance value). The first original reference resistance value R ref1,0 is associated with the first reference sensing part 30. For example, before the gas sensing device 200 leaves the factory, a target gas with a specified concentration (such as 0 ppm) is brought into contact with the heated first reference sensing part 30. At this time, the controller 70' detects the resistance value of the first reference sensing part 30, and uses this resistance value as the first original reference resistance value R ref1,0 , which is stored in the existing storage element or storage device of the controller 70' itself. For example, the first reference coefficient of variation α is the ratio of the first measured reference resistance value R ref1 and the first original reference resistance value R ref1,0 , as shown in Equation 36. The first reference coefficient of variation α is used to reflect the degree of influence of the current environmental changes (such as unstable oxygen adsorption or changes in temperature and humidity) on the first reference sensing part 30.

[0164] α = R ref1 / R ref1, 0 (Equation 36)

[0165] Please refer to step S104, the controller 70' calculates the target gas concentration value based on the first reference coefficient of variation α, multiple first relationship functions F 1(k ppm) , multiple second original reference resistance values R ref2,0,(k ppm) (the first original reference impedance value), the measured target resistance value R sen , the second measured reference resistance value R ref2 , multiple second relationship functions F 2(kppm) and the target gas concentration conversion function.

[0166] The number of the first relationship functions F 1(k ppm) , the second original reference resistance value R ref2,0,(k ppm) and the second relationship functions F 2(k ppm) is determined by the number of specified concentration values. For example, if the specified concentration values are preset to 4: 0 ppm, 20 ppm, 100 ppm, and 200 ppm, then the corresponding first relationship functions are 4: F 1(0ppm) , F 1(20ppm) , F 1(100ppm) and F 1(200ppm) ; the corresponding second original reference resistance values are 4: R ref2,0,(0ppm) , R ref2,0,(20ppm), R ref2,0,(100ppm) and R ref2,0,(200ppm) ; there are 4 corresponding second relationship functions: F 2(0ppm) , F 2(20ppm) , F 2(100ppm) and F 2(200ppm) . Based on the conditions of the target gas at each specified concentration value, each of the first relationship functions F 1(k ppm) is the correlation between the first reference sensing part 30 and the second reference sensing part 50. For example, the first relationship function F 1(k ppm) is the dependence relationship between the first measured reference resistance value R ref1 and the second measured reference resistance value R ref2 . Take another example, the first relationship function F 1(k ppm) is the dependence relationship between the variation rate of the first measured reference resistance value R ref1 and the variation rate of the second measured reference resistance value R ref2 . Regarding multiple second original reference resistance values R ref2,0,(k ppm) , for example, before the gas sensing device 200 leaves the factory, target gases with multiple specified concentrations (e.g., 0 ppm, 20 ppm, 100 ppm, 200 ppm) are respectively brought into contact with the heated second reference sensing part 50, and the controller 70’ detects the resistance values of the second reference sensing part 50 at these specified concentrations (e.g., R ref2,0,(0ppm) , R ref2,0,(20ppm) , R ref2,0,(100ppm) and R ref2,0,(200ppm) ), and uses these resistance values as the multiple second original reference resistance values R ref2,0,(k ppm) , storing them in the existing storage element or storage device of the controller 70’ itself. Based on the conditions of the target gas at each specified concentration value, each of the second relationship functions F 2(k ppm) is the correlation between the second reference sensing part 50 and the target sensing part 40. For example, the second relationship function F 2(k ppm) is the dependence relationship between the second measured reference resistance value R ref2 and the measured target resistance value R sen . Take another example, the second relationship function F 2(k ppm) is the dependence relationship between the variation rate of the second measured reference resistance value R ref2 and the variation rate of the measured target resistance value R sen .

[0167] Please refer to Figure 12B , which shows Figure 12AThe detailed process of step S104. Please refer to step S1041, the controller 70' calculates a plurality of second reference variation coefficients γ according to the first reference variation coefficient α and a plurality of first relationship functions F 1(k ppm) Calculate a plurality of second reference variation coefficients γ (k ppm) . The second reference variation coefficient γ (k ppm) The quantity of is determined by the quantity of the first relationship function F 1(k ppm) . Continuing with the previous example, the controller 70' substitutes the reference variation coefficient α into 4 first relationship functions F 1(k ppm) respectively to obtain 4 second reference variation coefficients γ (k ppm) , which includes γ (0ppm) , γ (20ppm) , γ (100ppm) and γ (200ppm) , as shown in the following equations 37, 38, 39 and 40.

[0168] γ (0ppm) =F 1(0ppm) (α) (Equation 37)

[0169] γ (20ppm) =F 1(20ppm) (α) (Equation 38)

[0170] γ (100ppm) =F 1(200ppm) (α) (Equation 39)

[0171] γ (100ppm) =F 1(200ppm) (α) (Equation 40)

[0172] Please refer to step S1043, the controller 70' calculates a plurality of second predicted reference resistance values R ref2,0,(kppm) and a plurality of second reference variation coefficients γ (k ppm) to calculate a plurality of second predicted reference resistance values R ref2,pre,(k ppm) (the second predicted reference impedance value, that is, the plurality of partition reference values described in the partition calculation stage B3). Regarding the calculation method of step S1043, continuing with the previous example, for a plurality of specified concentrations (for example: 0 ppm, 20 ppm, 100 ppm, 200 ppm), the product of the second original reference resistance value R ref2,0,(k ppm) corresponding to the same specified concentration and the second reference variation coefficient γ (k ppm) is used as the second predicted reference resistance value R ref2,pre,(kppm) (for example: R ref2,pre,(0ppm) , Rref2,pre,(20ppm) , R ref2,pre,(100ppm) , and R ref2,pre,(200ppm) ), as shown in Equations 41, 42, 43, and 44 below.

[0173] R ref2,pre,(0ppm) = R ref2 0,(0ppm) ×γ (0ppm) (Equation 41)

[0174] R ref2,pre,(20ppm) = R ref2 0,(20ppm) ×γ (20ppm) (Equation 42)

[0175] R ref2,pre,(100ppm) = R ref2 0,(100ppm) ×γ (100ppm) (Equation 43)

[0176] R ref2,pre,(200ppm) = R ref2 0,(200ppm) ×γ (200ppm) (Equation 44)

[0177] Please refer to Step S1044. The controller 70' selects one from multiple second predicted reference resistance values R ref2 (i.e., the comparison reference value described in the partition comparison stage B5). For example, the controller 70' calculates the multiple differences between the second measured target resistance value R ref2,pre,(k ppm) and the multiple second predicted reference resistance values R ref2 and selects the second predicted reference resistance value R ref2,pre,(k ppm) corresponding to the minimum of these differences (or the minimum of the absolute values of these differences). ref2,pre,(x ppm) .

[0178] Please refer to Step S1045. The controller 70' determines whether it meets the resistance variation correlation (admittance variation correlation) based on the second measured reference admittance value R ref2 , the second original reference resistance value R ref2,0,(x ppm) , the measured target resistance value R sen and one of the multiple original target resistance values R sen 0,(k ppm) (original target admittance value) R sen 0,(x ppm) , where the second original reference resistance value R ref2,0,(x ppm) and the multiple original target resistance values Rsen 0,(k ppm) wherein the said R sen 0,(x ppm) The specified concentration x corresponding to the two of them and the second predicted reference resistance value R ref2,pre,(x ppm) correspond to the same specified concentration x. For example, the resistance variation correlation is the dependency relationship between the resistance value variation of the second reference sensing part 50 and the resistance value variation of the target sensing part 40. Take another example, the resistance variation correlation is the dependency relationship between the resistance value variation rate of the second reference sensing part 50 and the resistance value variation rate of the target sensing part 40. The said resistance value variation is the difference between the measured resistance value and the original resistance value. The said resistance value variation rate is the quotient of the measured resistance value divided by the original resistance value. Taking the resistance value variation rate as an example, the controller 70’ determines whether the values on both sides of Equation 45 are within a tolerance range e, as shown in Equation 45.

[0179] (R sen / R sen 0, (k ppm) ) – (R ref2 / R ref2 ,0, (k ppm) ) < e (Equation 45)

[0180] wherein, the first ratio is R sen / R sen 0,(k ppm) , and the second ratio is R ref2 / R ref2 ,0,(k ppm)

[0181] If the judgment result of step S1045 is "No" (non-compliance with the impedance variation correlation), it means that one of the target sensing part 40 and the second reference sensing part 50 is not operating properly. Therefore, step S1046 is executed to replace the other target sensing part or the other second reference sensing part. After step S1046 is executed, return to step S101 to re-execute the gas concentration sensing method of the fourth embodiment. If the judgment result of step S1045 is "Yes" (compliance with the impedance variation correlation), then step S1047 is executed.

[0182] Please refer to step S1047. The controller 70’ calculates the target coefficient of variation β based on the second measured reference resistance value R ref2 , the second original reference resistance value R ref2 ,0,(k ppm) and the second relationship function F 2(k ppm) ​(k ppm) The target coefficient of variation β (x ppm) That is, it is used as a parameter in stage B7 of the concentration calculation. The second original reference resistance value R ref2 , 0, (x ppm) and the second predicted reference resistance value R selected in step S1045 ref2 , pre, (x ppm) and the second relationship function F 2(x ppm) All three correspond to the same concentration x. Regarding the target coefficient of variation β (k ppm) For its calculation method, for example, the controller 70' uses the second measured reference resistance value R ref2 divided by the second original reference resistance value R ref2 , 0, (k ppm) The value obtained by substituting the quotient into the second relationship function is used as the target coefficient of variation β (k ppm) , as shown in Equation 46.

[0183] β (k ppm) = F2 (k ppm) (R ref2 / R ref2 , 0, (k ppm) ) (Equation 46)

[0184] Please refer to step S1048. The controller 70' calculates the corrected resistance value R sen based on the measured target resistance value R (k ppm) and the target coefficient of variation β cal (corrected impedance value). Regarding the calculation method of the corrected resistance value R cal For example, the controller 70' uses the measured target resistance value R sen divided by the target coefficient of variation β (k ppm) The quotient value is used as the corrected resistance value R cal , as shown in Equation 47.

[0185] R cal = R sen / β (k ppm) (Equation 47)

[0186] Please refer to step S1049. The controller 70' substitutes the corrected resistance value R cal into the target gas concentration conversion function to obtain the target gas concentration value.

[0187] The above description applies to two embodiments of the gas concentration sensing method of the first embodiment of the gas sensing device 100 and four embodiments of the gas concentration sensing method of the second embodiment of the gas sensing device 200. In the above six embodiments, after obtaining the target gas concentration value, the controller 70' may further include, according to the target gas concentration value and the calibration resistance value R cal to update the standard curve. The standard curve is the function curve of the "target gas concentration conversion function".

[0188] In practice, before the gas sensing devices 100 and 200 leave the factory, the built-in resistance values (built-in impedance values) of the target sensing part 40 when contacting various specified concentrations of the target gas are pre-detected. In other words, each built-in impedance value is associated with the target sensing part 40 and each specified concentration value corresponds to one of these built-in impedance values, and the target gas concentration conversion function is associated with these specified concentration values and these built-in impedance values. Record the above specified concentration values and the detected built-in resistance values in Table 1 below. After the gas sensing devices 100 and 200 are actually applied and the target gas concentration value is obtained, the controllers 70 and 70' judge whether the calibration concentration value falls within the update interval corresponding to a certain specified concentration value in Table 1. If the judgment result is "yes", the controllers 70 and 70' use the calibration resistance value R cal to replace the built-in resistance value corresponding to the specified concentration value in Table 1. If the judgment result is "no", the controllers 70 and 70 add a new column of the calibration resistance value R cal and the target gas concentration value to Table 1.

[0189] Table 1

[0190] Internal resistance value (KΩ) Specified concentration (ppm) 4805 1.28 3576 25.1 2107 107.1 1407 215.8

[0191] For example, assuming that the update interval is 5 ppm, in the nth measurement, the calibration resistance value (calibration impedance value) R cal is 3749 KΩ and the target gas concentration value is 22.5 ppm. In this example, the controllers 70 and 70' find that the field with the specified concentration value of 25.1 ppm meets the update requirement (25.1 - 5 < 22.5 < 25.1 + 5). Therefore, the controllers 70 and 70' update the field in Table 1 with the built-in resistance value of 3576 KΩ.

[0192] Continuing from the previous example, assuming that in the (n + 1)th measurement, the calibration resistance value R calis 2013 KΩ, and the target gas concentration value is 124.0 ppm. In this example, the controllers 70, 70' did not find that the update interval of a specified concentration value contains this calibrated concentration value (107.1 - 5 < 124.5, but 107.1 + 5 < 124.5). Therefore, the controllers 70, 70' added the measured data of "resistance - concentration" (2013, 124.0) to Table 1. According to the above two examples, Table 1 was updated to Table 2 below.

[0193] Table 2

[0194]

[0195]

[0196] Based on the above update strategy (the controllers 70, 70' update these built - in impedance values and selectively update the specified concentration value according to the calibrated impedance value, the target gas concentration value, multiple built - in impedance values, and the update interval), the calibrated resistance value and the calibrated concentration value of the gas sensing device 100 each time will be fed back to the standard curve or the table corresponding to the standard curve. For the gas concentration sensing method proposed in the present invention, the above update strategy has the effect of dynamic calibration. And when the sensitivity of the sensing material to the target gas changes, it can still ensure that the gas sensing device 100 outputs an accurate target gas concentration value.

[0197] Please refer to Figure 13 , which shows the flowchart of establishing the standard curve of the target gas concentration conversion function.

[0198] Please refer to step S111, introduce a target gas with a specified concentration. For example, first introduce a target gas with a specified concentration of 25 ppm into the gas sensing devices 100, 200, and the heater 10 generates heat energy to raise the temperature of the sensing material parts 30 - 60, and introduce the target gas into the gas sensing devices 100, 200.

[0199] Please refer to step S113, measure the resistance value of the target sensing material part 40. Specifically, the controllers 70, 70' detect the measured target resistance value R of the target sensing material part 40 sen , for example, is 3576 KΩ.

[0200] Please refer to step S115, write the specified concentration and the resistance value. Specifically, the controllers 70, 70' store the data (25 ppm, 3576 KΩ) in the existing storage element or storage device of the controller 70' itself. This step is equivalent to adding a coordinate point.

[0201] Please refer to step S117 to determine whether the number of data is sufficient. Specifically, the controllers 70, 70' first determine whether the number of added coordinate points is sufficient to establish a standard curve. If the judgment result is yes, move to step S118 to establish the standard curve. If the judgment result is no, move to step S119.

[0202] Please refer to step S119 to introduce a target gas with another specified concentration. For example, the controllers 70, 70' introduce a target gas with a specified concentration of 100 ppm into the gas sensing devices 100, 200, and then repeat the processes of steps S113 to S117. Until it is determined in step S117 that the number of data is sufficient, the establishment of the standard curve for another specified concentration can be completed.

[0203] In summary, the gas sensing device and the gas concentration sensing method capable of automatic calibration proposed by the present invention use the reference sensing part to provide self-compensating information to the target sensing part, so the drifted resistance value can be calibrated. In addition, the present invention can dynamically correct the standard curve pre-established by the gas sensing device according to the resistance value and the concentration value after each calibration, so as to provide a more accurate gas concentration sensing result for the next sensing. Overall, the present invention can effectively calibrate the sensing result, and the data output by the gas sensing element itself can provide information for data update, that is, when the sensing material of the gas sensing device varies in sensitivity due to factors such as the environment, its own aging, or incomplete burn-in, this variation can be detected and dynamically calibrated; in addition, even if the sensing material itself ages or is poisoned, the variation in its sensitivity can still be tracked by modifying the standard curve, thereby extending the service life of the gas sensing device.

Claims

1. A gas concentration sensing method, applicable to a gas sensing device capable of sensing the concentration of a target gas in a gas to be measured, wherein the gas sensing device includes a heater, a reference sensing element part, a target sensing element part, and a controller, and the sensitivity of the reference sensing element part to the target gas is lower than that of the target sensing element part to the target gas. The gas concentration sensing method includes: An impedance value acquisition stage, using the heater to generate heat energy to raise the temperatures of the reference sensing element part and the target sensing element part to the same temperature. When the reference sensing element part and the target sensing element part contact the gas to be measured, using the controller to detect the measured reference impedance value of the reference sensing element part and the measured target impedance value of the target sensing element part; A partition calculation stage, using the controller to calculate multiple predicted target impedance values based on the measured reference impedance value and multiple relationship functions, where the relationship functions and the predicted target impedance values all correspond to multiple specified concentration values; A partition comparison stage, using the controller to compare the measured target impedance value with the predicted target impedance values to select one of the specified concentration values; and A concentration calculation stage, using the controller to calculate the target gas concentration value based on one of multiple target variation coefficients and the measured target impedance value, where one of the target variation coefficients corresponds to one of the specified concentration values; Wherein the concentration calculation stage further includes: Using the controller to calculate a corrected impedance value based on the measured target impedance value and one of the target variation coefficients; and Using the controller to substitute the corrected impedance value into the target gas concentration conversion function to obtain the target gas concentration value; Wherein the target gas concentration conversion function is associated with the specified concentration values and multiple built-in impedance values, each of the built-in impedance values is associated with the target sensing element part, and each of the specified concentration values corresponds to one of the built-in impedance values; The method further includes: using the controller to update the built-in impedance values and selectively update the specified concentration values based on the corrected impedance value, the target gas concentration value, the built-in impedance values, and an update range, and the update range is the positive and negative error range of the specified concentration.

2. The gas concentration sensing method according to claim 1, wherein the partition calculation stage further includes: Using the controller to calculate a reference variation coefficient based on the measured reference impedance value and the original reference impedance value; Using the controller to calculate the target variation coefficients based on the reference variation coefficient and the relationship functions; and Using the controller to calculate the predicted target impedance values based on multiple original target impedance values and the target variation coefficients; wherein The original reference impedance value is associated with the reference sensing element part; The original target impedance values are associated with the target sensing element part and the target gas of the specified concentration values; and Each of the relationship functions is the correlation when the reference sensing element part and the target sensing element part contact the target gas of the specified concentration.

3. A gas concentration sensing method, applicable to a gas sensing device capable of sensing the concentration of a target gas in a gas to be measured, wherein the gas sensing device includes a heater, a first reference sensing element part, a second reference sensing element part, a target sensing element part, and a controller, and the sensitivity of the first reference sensing element part to the target gas and the sensitivity of the second reference sensing element part to the target gas are both lower than the sensitivity of the target sensing element part to the target gas. The gas concentration sensing method includes: An impedance value obtaining stage, using the heater to generate heat energy to raise the temperatures of the reference sensing element part and the target sensing element part to the same temperature. When the first reference sensing element part, the second reference sensing element part, and the target sensing element part are in contact with the gas to be measured, using the controller to detect a first measured reference impedance value of the first reference sensing element part, a second measured reference impedance value of the second reference sensing element part, and a measured target impedance value of the target sensing element part; A partition calculation stage, using the controller to calculate a plurality of partition reference values according to at least one of the first measured reference impedance value and the second measured reference impedance value and a plurality of relationship functions, wherein the relationship functions and the partition reference values all correspond to a plurality of specified concentration values; A partition comparison stage, using the controller to compare the partition reference values with a comparison reference value to select one of the specified concentration values; and A concentration estimation stage, using the controller to estimate the target gas concentration value according to a target coefficient of variation and the measured target impedance value, wherein the target coefficient of variation corresponds to one of the specified concentration values; wherein the partition calculation stage includes: Using the controller to calculate a plurality of second predicted reference impedance values according to the first measured reference impedance value and a plurality of first relationship functions; wherein the first relationship functions are the relationship functions, and each of the first relationship functions is the correlation when the first reference sensing element part and the second reference sensing element part are in contact with the target gas of the specified concentration values.

4. The gas concentration sensing method according to claim 3, wherein the partition calculation stage further includes: Using the controller to calculate a first reference coefficient of variation according to the first measured reference impedance value and a first original reference impedance value; Using the controller to calculate a plurality of second reference coefficients of variation according to the first reference coefficient of variation and a plurality of first relationship functions; and Using the controller to calculate a plurality of second predicted reference impedance values according to a plurality of second original reference impedance values and the second reference coefficients of variation; wherein the first original reference impedance value is associated with the first reference sensing element part; the second original reference impedance values are associated with the second reference sensing element part and the target gas of the specified concentration values; and the first relationship functions are the relationship functions, and each of the first relationship functions is the correlation when the first reference sensing element part and the second reference sensing element part are in contact with the target gas of the specified concentration values.

5. The gas concentration sensing method according to claim 4, wherein the comparison reference value is the second measured reference impedance value, and the partition reference values are the second predicted reference impedance values.

6. The gas concentration sensing method according to claim 5, wherein the concentration estimation stage includes: The controller calculates the target coefficient of variation based on one of the second measured reference impedance values, one of the second original reference impedance values, and one of the multiple second relationship functions; The controller calculates a corrected impedance value based on the measured target impedance value and the target coefficient of variation; and The controller substitutes the corrected impedance value into a target gas concentration conversion function to obtain the target gas concentration value; wherein The second original reference impedance values are associated with the second reference sensing part and the target gas of the specified concentration values; The second relationship functions are the correlations when the second reference sensing part and the target sensing part contact the target gas of the specified concentration values; and The specified concentration value corresponding to one of the second original reference impedance values and one of the second relationship functions is the same as the one of the specified concentration values selected by the controller in the partition comparison stage.

7. The gas concentration sensing method according to claim 6, wherein the concentration calculation stage further includes: The controller determines whether the impedance variation correlation is met based on one of the second measured reference impedance values, one of the second original reference impedance values, the measured target impedance value, and one of the multiple original target impedance values; wherein When the controller determines that the impedance variation correlation is not met, the controller selectively replaces the target sensing part with another target sensing part or replaces the second reference sensing part with another second reference sensing part; When the controller determines that the impedance variation correlation is met, the controller calculates the target coefficient of variation based on one of the second measured reference impedance values, one of the second original reference impedance values, and one of the second relationship functions; wherein The original target impedance values are associated with the target sensing part and the target gas of the specified concentration values; and The specified concentration value corresponding to one of the original target impedance values is the same as the one of the specified concentration values selected by the controller in the partition comparison stage.

8. The gas concentration sensing method according to claim 7, wherein the controller determines whether the impedance variation correlation is met based on one of the second measured reference impedance values, one of the second original reference impedance values, the measured target impedance value, and one of the original target impedance values includes: The controller calculates a first ratio of the measured target impedance value and one of the original target impedance values; The controller calculates a second ratio of one of the second measured reference impedance values and one of the second original reference impedance values; and The controller calculates the difference between the first ratio and the second ratio, and determines whether the impedance variation correlation is met based on whether the difference is within the allowable error range.

9. The gas concentration sensing method according to claim 3, wherein the comparison reference value is the second measured reference impedance value, and the partition reference values are the second predicted reference impedance values.

10. The gas concentration sensing method according to claim 9, wherein the concentration calculation stage includes: The controller calculates the target coefficient of variation based on the second measured reference impedance value, one of the multiple second original reference impedance values, and one of the multiple second relationship functions; The controller calculates a corrected impedance value based on the measured target impedance value and the target coefficient of variation; and The controller substitutes the corrected impedance value into the target gas concentration conversion function to obtain the target gas concentration value; where The second original reference impedance values are associated with the second reference sensing part and the target gas of the specified concentration values; The second relationship functions are the correlations when the second reference sensing part and the target sensing part contact the target gas of the specified concentration values; and The specified concentration value corresponding to one of the second original reference impedance values and one of the second relationship functions is the same as the one selected by the controller from the specified concentration values in the partition comparison stage.

11. The gas concentration sensing method according to claim 3, wherein the partition calculation stage further includes: The controller calculates multiple first predicted coefficients of variation based on the second measured reference impedance value, the multiple second original reference impedance values, and the multiple first relationship functions, where the second original reference impedance values are associated with the second reference sensing part and the target gas of the specified concentration values; and The first relationship functions are the relationship functions, and each of the first relationship functions is the correlation when the first reference sensing part and the second reference sensing part contact the target gas of the specified concentration values.

12. The gas concentration sensing method according to claim 11, wherein the partition comparison stage further includes: The controller calculates a first reference coefficient of variation based on the first measured reference impedance value and the first original reference impedance value; And The controller selects one from the first predicted coefficients of variation based on the first reference coefficient of variation; Where The first original reference impedance value is associated with the first reference sensing part; The first reference coefficient of variation is the comparison reference value; and The first predicted coefficients of variation are the partition reference values.

13. The gas concentration sensing method according to claim 12, wherein the concentration calculation stage further includes: The controller calculates the target coefficient of variation based on the one selected from the first predicted coefficients of variation and one of the multiple second relationship functions; The controller calculates a corrected impedance value based on the measured target impedance value and the target coefficient of variation; and The controller substitutes the corrected impedance value into the target gas concentration conversion function to obtain the target gas concentration value; where The second relationship functions are the correlations when the second reference sensing part and the target sensing part contact the target gas of the specified concentration values; and The specified concentration value corresponding to one of the second relationship functions is the same as the one selected by the controller from the specified concentration values in the partition comparison stage.

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