WO2015159663A1

WO2015159663A1 - Humidity measurement device

Info

Publication number: WO2015159663A1
Application number: PCT/JP2015/059025
Authority: WO
Inventors: 有毅磯谷; 浩昭星加; 余語　孝之; 崇裕三木; 丈夫細川
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2014-04-16
Filing date: 2015-03-25
Publication date: 2015-10-22
Also published as: JPWO2015159663A1; JP6294960B2

Abstract

The purpose of the present invention is to provide a humidity measurement device that is highly reliable even when contaminants are adhered thereto or a relative humidity measurement device has deteriorated. In order to achieve said purpose, this humidity measurement device calculates absolute moisture volumes by using relative humidity signals and temperature signals and is characterized by comprising: a characteristics diagnostic unit that calculates an estimated relative humidity value in a second state, using an absolute moisture volume calculated in a first state and a temperature measured in the second state, and calculates the amount of deterioration in characteristics in the second state, by comparing this estimated value and an actual measurement value for relative humidity measured in the second state; and a correction unit that corrects relative humidity measurement values by using said amount of deterioration in characteristics.

Description

Humidity measuring device

The present invention relates to a humidity measuring device installed in an intake system of an internal combustion engine of an automobile.

A humidity measuring device is one of sensors that are attached to the intake system of an automobile internal combustion engine to improve fuel efficiency and environmental performance. The humidity measuring device includes a relative humidity measuring element, a temperature measuring element provided in the vicinity of the relative humidity measuring element, and a circuit unit for controlling the relative humidity measuring element and the temperature measuring element. The absolute moisture content is calculated using the output of the measuring element, and a signal corresponding to the absolute moisture content is transmitted to the outside.

Here, the gas to be measured flowing through the main air passage contains contaminants such as dust that could not be trapped by the air cleaner, and the relative humidity is measured by attaching the contaminants to the moisture sensitive film. There is a problem that the accuracy is deteriorated and the calculation accuracy of the absolute water content in the humidity measuring device is deteriorated. Patent document 1 is mentioned as a prior art which suppresses the deterioration of the precision by fouling substance adhesion to a relative humidity measuring element.

In Patent Document 1, the detection unit is heated to a predetermined temperature to perform so-called zero point correction (zero point adjustment), while the detection unit is condensed to form a so-called 100% R.D. H value correction (100 percent R.H value adjustment), zero adjustment and 100% R.H. A technique for calibrating a humidity sensor by correcting the slope of a humidity calculation line with an adjustment value in H value adjustment is disclosed.

According to Patent Literature 1, even if the humidity sensor continues to be used for a certain period of time and the measured value is deviated, the humidity sensor can be calibrated easily and quickly at the measurement site.

JP 2002-156348 A

A humidity measuring device attached to an intake system of an internal combustion engine of an automobile tends to have a higher mounting density in the humidity measuring device with downsizing and multi-functionality. Therefore, when the relative humidity measuring element is heated to a high temperature, a large amount of heat is transmitted to a processing circuit such as an LSI or a microcomputer provided in the humidity measuring device. In particular, since these processing circuits are vulnerable to heat, if the relative humidity measuring element is heated too high, there is a possibility that the processing circuit will fail or malfunction. Therefore, it is not desirable to heat the relative humidity measuring element to a high temperature.

According to Patent Document 1, when zero adjustment is performed, the detection unit is heated to a critical temperature of water of 370.946 ° C.

Therefore, Patent Document 1 leaves room for improvement with respect to the above-described problems.

An object of the present invention is to provide a humidity measuring device with high reliability even in the state of contaminant adhesion and the deterioration state of the relative humidity measuring device.

In order to achieve the above object, the humidity measuring device of the present invention is a humidity measuring device that calculates an absolute moisture amount using a relative humidity signal and a temperature signal, and the absolute moisture amount calculated in the first state and the second state. The estimated value of relative humidity in the second state is calculated using the temperature measured in step 2, and the characteristic deterioration amount in the second state is compared by comparing the estimated value and the actual value of relative humidity measured in the second state. And a correction unit that corrects a measured value of relative humidity using the characteristic deterioration amount.

According to the present invention, it is possible to provide a highly reliable humidity measuring device even in a pollutant attached state or a deteriorated state of the relative humidity measuring device.

1 is a perspective view of a relative humidity measuring device housing including a main air passage according to an embodiment of the present invention. 1 is a perspective view of a relative humidity measuring device housing according to an embodiment of the present invention. 1 is a perspective view of a relative humidity measuring device housing according to an embodiment of the present invention. The side view of the relative humidity measuring device housing | casing by one Example of this invention The block diagram which shows the structure by one Example of this invention. Explanatory drawing explaining the characteristic diagnosis process and relative humidity correction amount by one Example of this invention Explanatory drawing explaining the characteristic diagnosis process and relative humidity correction amount by one Example of this invention Activity diagram showing characteristic diagnosis processing and relative humidity correction amount calculation processing according to an embodiment of the present invention Explanatory drawing explaining the relative humidity correction method by one Example of this invention Activity diagram showing characteristic diagnosis processing and relative humidity correction amount calculation processing according to an embodiment of the present invention Activity diagram showing characteristic diagnosis processing and relative humidity correction amount calculation processing according to an embodiment of the present invention Explanatory drawing explaining the relative humidity correction method by one Example of this invention The front view and sectional drawing of the housing | casing of an intake air flow rate measuring device by one Example of this invention 1 is an inclined view of a chip package according to an embodiment of the present invention. Activity diagram showing characteristic diagnosis processing and relative humidity correction amount calculation processing according to an embodiment of the present invention Activity diagram showing characteristic diagnosis processing and relative humidity correction amount calculation processing according to an embodiment of the present invention

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS.

As shown in FIGS. 1, 2 (a), 2 (b), and 3, the humidity measuring device 22 in the first embodiment includes a housing support 11, a screw hole 12, a connector 13, and a housing 14. A cover 15, a main bypass 16 that takes in a portion of the intake air flowing through the main air passage 1, a sub-bypass 17 formed by the housing 14 and the cover 15, a heating element 25, a temperature measuring element 26A, A humidity measuring element 27A and a control element 23 are provided.

The humidity measuring device 22 is inserted from an insertion hole provided in the main air passage wall 2 so that the main bypass 16 can take in part of the intake air flowing through the main air passage 1. The humidity detection device 22 is fixed to the mounting base 3 with screws inserted into the screw holes 12 via the housing support portion 11. A gap generated when the humidity detecting device 22 is fixed to the mounting base 3 is filled with the O-ring 18.

The relative humidity measuring element 27 </ b> A is provided in the sub-bypass 17 branched from the main bypass 16. Since most of the contaminated matter taken into the main bypass 16 travels straight due to inertial force, the entry of the contaminated matter into the sub bypass 17 can be suppressed. For this reason, by providing the relative humidity measuring element 27A in the sub-bypass 17, it is possible to suppress the deterioration of the relative humidity measuring element 27A due to adhesion of the contaminated material.

As shown in FIG. 4, the control device 21 includes a temperature signal processing unit 26B, a relative humidity signal processing unit 27B, an absolute water content calculating unit 28B, a characteristic diagnosis processing unit 29A, a relative humidity correction amount calculating unit 29B, It has an output unit 26C, a relative humidity output unit 27C, and an absolute water content calculation unit 28C. After the output of the temperature measuring element 26A is received and processed by the temperature signal processing unit 26B, the corresponding temperature 26 is output by the temperature output unit 26C, and the output of the relative humidity measuring element 27A is received and processed by the relative humidity signal processing unit 27B. After that, the relative humidity output unit 27C outputs the corresponding relative humidity 27. Further, the absolute water content calculation unit 28B is executed using the output of the temperature signal processing unit 26B and the output of the relative humidity signal processing unit 27B, and the corresponding absolute water content 28 is output by the absolute water content output unit 28C.

Deterioration of the output characteristics of the relative humidity measuring element due to the adhesion and deterioration of soiling substances will be described with reference to FIG. In FIG. 5A, the vertical axis represents the characteristic deterioration amount, and the horizontal axis represents the relative humidity (hereinafter referred to as reference relative humidity) of the measured environment atmosphere. When the contaminant is attached to the relative humidity measuring element 27A or the relative humidity measuring element 27A deteriorates with time, the relative humidity measuring element 27A measures lower than the reference relative humidity. Measurement errors occur when measuring higher than the reference relative humidity. Therefore, when the relative humidity measuring element 27A is soiled or deteriorates with time, for example, the first measurement point 31 having a negative characteristic deterioration amount or the second measurement point 32 having a positive characteristic deterioration amount is taken. The output characteristic 30 is changed. Hereinafter, a description will be given of a case where correction is performed by taking the output characteristic 30 of the relative humidity at the time of characteristic deterioration as an example. In this correction, the state of characteristic deterioration is not limited to the output characteristic 30, but a positive characteristic deterioration amount in all relative humidity regions. It is also possible to correct various output characteristics such as an output characteristic having, an output characteristic that rises to the right, and a non-linear characteristic.

The characteristic diagnosis and output correction in the first embodiment will be described with reference to FIGS.

Characterization is achieved by executing an absolute water content calculation process, a relative humidity estimation process during temperature control, and a characteristics diagnosis process.

First, it is determined whether or not the gas in the measured environment atmosphere is exchanged in the measured environment atmosphere state grasping step ST1 during the absolute moisture amount calculation process. Here, in general, the relationship between the absolute water content, the relative humidity, and the temperature is obtained by the following mathematical formula 1. The present invention focuses on the fact that the absolute moisture content does not change when the gas in the ambient atmosphere to be measured is not exchanged.

In Equation 1, SH is the absolute moisture content [g / kg] of the measured environment atmosphere, RH is the relative humidity [% RH] of the measured environment atmosphere, Temp is the temperature [° C.] of the measured environment atmosphere, and Press is the measured value. The atmospheric pressure is atmospheric pressure [Pa].

In the measurement environment atmosphere exchange state determination step ST2, it is determined whether or not the gas in the measurement environment atmosphere is exchanged based on the result of the measurement environment atmosphere state grasping step ST1. If it is determined in the measurement environment atmosphere exchange state determination step ST2 that the gas in the measurement environment atmosphere has been exchanged, the process ends without performing the subsequent processing. On the other hand, if it is determined that the gas in the measured environment atmosphere is not replaced in the measured environment atmosphere exchange state determination step ST2, the process proceeds to the temperature measurement and relative humidity measurement step ST3.

The case where it is determined that the gas in the ambient atmosphere to be measured has not been exchanged is, for example, when the engine is stopped, such as during idling stop, keyless entry, or smart entry. It is also possible to determine whether or not the gas in the ambient atmosphere to be measured has been exchanged by measuring the flow rate of the fluid flowing through the main air passage 1 with an air flow sensor or the like.

Measurement step ST3 performs temperature measurement step ST3A and relative humidity measurement step ST3B in parallel.

Absolute water content calculation step ST4 calculates the absolute water content by applying the temperature obtained in temperature measurement step ST3A and the relative humidity obtained in relative humidity measurement step ST3B to Equation 1. At this time, the pressure is 1 atm (101325 [Pa]).

Next, the data acquisition step ST5 is started in the relative humidity estimation process. In the data acquisition step ST5, the temperature control step ST6 for controlling the gas temperature of the ambient atmosphere to be measured by controlling the heating temperature of the heating element 25, and the measurement step ST7 are performed in parallel with the temperature control step ST6. In the measurement step ST7, a temperature measurement step ST7A for measuring the gas temperature in the measurement environment atmosphere with the temperature measurement element 26A, and a relative humidity measurement step ST7B for measuring the relative humidity of the gas in the measurement environment atmosphere with the relative humidity measurement element 27A. Do it in parallel. Note that the temperature control step ST6 is not limited to heating the heat generating element 25, and may be cooling by stopping the heating of the heat generating element 25. Then, the temperature control by the heating element 25 may be performed with a target temperature of the gas in the atmosphere to be measured that can be realized.

Here, when Equation 1 is transformed, the following Equation 2 for calculating the relative humidity is obtained. Assuming that the state before the temperature control step ST6 is the state A and the state during the temperature control step ST6 is the state B, the following Equation 3 for estimating the relative humidity in the state B is obtained.

In Equation 3, RH _Bestimate is the relative humidity [% RH] of the measured ambient atmosphere in state B.
, Temp _A is a temperature [° C.] of the measured environment atmosphere in the state A, and ΔTemp is a temperature difference [° C.] between the temperature of the measured environment atmosphere and the Temp _{A in} the state B.

Relative humidity estimation value calculation step ST8 applies the absolute water content in state A obtained in absolute water content calculation step ST4 and the temperature in state B obtained in temperature measurement step ST7A to Equation 3 so that An estimated value 31B of relative humidity is calculated. This is based on the fact that the absolute moisture content does not change between the state A and the state B when the gas in the atmosphere to be measured is not in the exchange state, so that the ideal relative humidity output characteristic 33 is obeyed. At this time, as in the absolute water content calculation step ST4, Press is set to 1 atm (101325 [Pa]). That is, the estimated relative humidity value calculating step ST8 calculates the estimated relative humidity value 31B in the state B from the measured actual humidity value 31A in the state A. In FIG. 5B, it is assumed that the state A is a temperature of 25 ° C., but this is not the case.

Next, a relative humidity difference calculating step ST9 is performed in the characteristic diagnosis process. The relative humidity difference calculation step ST9 includes an estimated value 31B of the relative humidity in the state B calculated in the estimated relative humidity value calculation step ST8 and an actual measured value 32A of the relative humidity in the state B actually measured in the relative humidity measurement step ST7B. And the characteristic deterioration amount 34 in the state B is calculated from the difference between the actually measured value and the estimated value.

In the characteristic diagnosis process, for example, when the characteristic deterioration amount 34 is equal to or greater than a certain threshold value, it is determined whether or not the detection accuracy of the relative humidity detection element has deteriorated to the extent that correction is necessary, and the process proceeds to relative humidity correction.

The relative humidity correction will be described with reference to FIG. Relative humidity correction is achieved by executing a relative humidity output correction process based on the result of the characteristic diagnosis. Here, the reference point 40A corresponds to the measurement point in the state A, and the first diagnosis point 40B corresponds to the measurement point in the state B.

The relative humidity output correction process has a difference correction step ST10. In the difference correction step ST10, the measurement error in the state B can be reduced by correcting the characteristic deterioration amount 34 in the state B with respect to the relative humidity in the state B. Alternatively, the difference correction step ST10 corrects the entire relative humidity and obtains the relative humidity output characteristic 42 in which the first diagnostic point is combined, thereby reducing the measurement error in the state B. .

In the first embodiment of the present invention, the characteristic deterioration amount is calculated using the estimated value and the actual measurement value after the temperature control, and the memory in the relative humidity measuring device has reference data for the specific relative humidity value. Instead, the amount of error can be reduced by correcting the characteristic deterioration amount in the entire relative humidity at an arbitrary relative humidity.

In addition, it is difficult to control the relative humidity value to an arbitrary value. For example, when the control is performed so that the relative humidity is 0% which is relatively easy to control, it is necessary to heat the measurement environment atmosphere to a high temperature. In the first embodiment, the temperature of the gas in the ambient atmosphere to be measured is controlled, and the characteristic deterioration amount is calculated from the estimated value and the measured value of the relative humidity after the temperature control. It is possible to calculate the characteristic deterioration amount.

Furthermore, since it is difficult to control the relative humidity value to an arbitrary value, when the relative humidity output in a certain state is compared with the reference value, the point at which the characteristic deterioration amount is obtained is limited. In the first embodiment, the estimated relative humidity value after actual temperature control and the actual measurement value are used. Therefore, it is possible to obtain the characteristic deterioration amount at various relative humidity.

Therefore, according to the first embodiment of the present invention, it is possible to provide a humidity measuring apparatus with high accuracy and reliability without heating to a high temperature.

A second embodiment of the present invention will be described with reference to FIGS. The description of the same configuration as that of the first embodiment is omitted.

As shown in FIG. 8A, after the relative humidity difference calculation step ST9 is executed, the difference calculation frequency diagnosis step ST11 is executed. The difference calculation frequency diagnosis step ST11 determines whether or not the immediately preceding characteristic deterioration amount calculation process is the first time, and if it is determined to be the first time, the characteristic deterioration amount calculation process is performed to calculate the characteristic deterioration amount at the next point. The process proceeds to the measurement environment atmosphere exchange state determination step ST17 via the first time confluence point P2.

In the measurement environment atmosphere exchange state determination step ST17, it is determined whether or not the gas in the measurement environment atmosphere is exchanged based on the result of the measurement atmosphere state grasping step 16. If it is determined in the measurement environment atmosphere exchange state determination step ST17 that the gas in the measurement environment atmosphere has been exchanged, the process proceeds to the confluence point P3 at the end of the correction process and ends. On the other hand, when it is determined in the measurement environment atmosphere exchange state determination step ST17 that the gas in the measurement environment atmosphere has not been exchanged, the process proceeds to the process merging point P1 when the correction process is continued. After the transition to P1, in order to make the relative humidity different from the first time, the heating temperature control of the heating element 25 is performed in ST6 so that the temperature is different from the first time, and in parallel with ST6, ST7, ST8, ST9 Execute. Thereby, the characteristic deterioration amount in relative humidity different from the first time is calculated.

Here, when it is determined in the difference calculation number diagnosis step ST11 that the characteristic deterioration amount is calculated after the first time, the process proceeds to the characteristic deterioration amount calculation step ST12 of the measured environment relative humidity 0%. The characteristic deterioration amount calculation step ST12 of the measured environment relative humidity of 0% is performed by applying two points of the first diagnosis point 40B and the second diagnosis point 40C to Equation 4 to thereby calculate the relative humidity output characteristic 40 at the time of characteristic deterioration. Ask for.

Here, y is the characteristic deterioration amount [% RH], RH is the relative humidity [% RH] of the measured environment, RH ₁ is the relative humidity [% RH] at the first diagnostic point 40B, and RH ₂ is the second diagnosis. Relative humidity [% RH] at point 40C, _Er1 is the characteristic deterioration amount [% RH] at the first diagnosis point 40B, and _Er2 is the characteristic deterioration amount [% RH] at the second diagnosis point 40C. By substituting 0 for RH in Equation 4, the characteristic deterioration amount 41 when the relative humidity of the ambient atmosphere to be measured is 0% is calculated.

After the characteristic deterioration amount calculation step ST12, the process proceeds to the characteristic deterioration amount correction steps 13 and 14.

Characteristic deterioration amount correction step 13 performs zero point adjustment by correcting the characteristic deterioration amount 41 when the relative humidity of the measurement environment atmosphere is 0% over the entire relative humidity, and obtains the relative humidity output characteristic 43 after the zero point adjustment.

In the characteristic deterioration amount correction step 14, correction other than the zero point (relative humidity 0%) is also performed. Therefore, the correction amount at an arbitrary relative humidity is calculated using the correction amount calculation formula shown in Equation 5 using the slope of Equation 4. calculate.

In Equation 5, u is the correction amount [% RH], and RH ₁ is the relative humidity at the first diagnostic point 40B [
% RH], RH ₂ is the relative humidity [% RH in the second diagnostic point 40C], E _r1 is characteristic deterioration amount in the first diagnostic point 40B [% RH], the E _r2 characteristic in said second diagnostic point 40C Deterioration amount [% RH].

The characteristic deterioration amount correction step 14 uses Equation 5 to set the relative humidity output characteristic 43 after the zero adjustment as a base point relative to 0% relative humidity, and uses the slope of the relative humidity output characteristic 43 to cover the entire relative humidity. A correction amount can be calculated. Thereby, the relative humidity output characteristic 44 is obtained.

Next, the process proceeds to the correction process continuation determination step ST15 to determine whether or not to continue the correction process. If it is determined in the correction process continuation determination step ST15 that the correction process is to end, the process proceeds to the confluence point P3 at the end of the correction process, and the characteristic diagnosis and the relative humidity correction are ended.

On the other hand, if it is determined that the correction process is to be continued in the correction process continuation determination step ST15, the process proceeds to the measured environment atmosphere exchange state determination step ST17 via the merging point P2 during the characteristic deterioration amount calculation process. Thereafter, the same steps as those for obtaining the second diagnostic point 40C are executed, and the third and subsequent diagnostic points are obtained.

Here, when three or more characteristic diagnosis points are obtained, a linear function equation is derived using the least square method, the relative humidity 0% using Equation 4, and the entire relative humidity region using Equation 5. Correct for. Note that when three or more characteristic diagnostic points are obtained, the method for correcting the entire relative humidity is not limited to the derivation of the linear function expression by the least square method, but multidimensional function approximation and the slope between the characteristic diagnostic points are respectively used. Even if various methods are employed, such as the estimation of the characteristic deterioration amount 41 when the relative humidity of the measured environment atmosphere is 0% is calculated using two characteristic diagnosis points closest to the relative humidity of the measured environment atmosphere Good.

Note that the third and subsequent diagnostic points are obtained after the characteristic deterioration amount calculation step ST12 and the characteristic deterioration amount correction steps ST13 and ST14. However, the present invention is not necessarily limited to this. Then, the characteristic deterioration amount calculation step ST12 and the characteristic deterioration amount correction steps ST13 and ST14 may be performed to correct the entire relative humidity.

In the second embodiment of the present invention, the characteristic deterioration characteristic is calculated using the characteristic deterioration amount at a plurality of relative humidity, and the relative humidity correction amount is calculated based on the characteristic deterioration characteristic at the plurality of relative humidity. The correction can be performed in the relative humidity of the entire region, and the relative humidity can be detected with high accuracy.

Further, it is difficult to control the relative humidity value to an arbitrary value. For example, when the control is performed so that the relative humidity is 100% which is relatively easy to control, it is necessary to cool the measured environment atmosphere to a low temperature. In the first embodiment, the temperature of the gas in the ambient atmosphere to be measured is controlled, and the characteristic deterioration amount is calculated from the estimated value and the measured value of the relative humidity after the temperature control. It is possible to calculate the characteristic deterioration amount.

Furthermore, since it is difficult to control the relative humidity value to an arbitrary value, when the relative humidity output is compared with a predetermined reference relative humidity value, the point where the characteristic deterioration amount is obtained is limited. In the first embodiment of the present invention, the estimated value and the actual measurement value of the relative humidity after temperature control are used, so that it is possible to obtain the characteristic deterioration amount at various relative humidity. Therefore, the characteristic deterioration amounts at a plurality of points can be obtained without changing the relative humidity value widely, and the diagnosis time can be shortened.

In the second embodiment, the characteristic deterioration amount calculation step ST12 and the characteristic deterioration amount correction steps ST13 and ST14 are performed in parallel with the temperature control step ST6. However, the present invention is not limited to this. As a configuration in which differential values of relative humidity at a plurality of diagnostic points measured during the control step ST6 are stored in a microcomputer or the like, and the characteristic deterioration amount is corrected using the differential values stored after the temperature control step 6 is completed. Also good.

A third embodiment of the present invention will be described with reference to FIG. In addition, while omitting the description of the same configuration as the first embodiment and the second embodiment, the control executor is different but the same processing is indicated by adding 'at the end and omitting the description similarly. .

In the third embodiment, a part or all of the calculation and correction performed by the relative humidity measuring device are executed by the control device.

As shown in FIG. 8 (b), each process except for the measured atmosphere state grasping step ST1 and the measured atmosphere state grasping step ST16 may be performed in the control device, and the share of the processing is lost. Any assignment can be made if it is done without any problem. Thereby, processing can be performed without concentrating on a certain control execution person, and the load of both a relative humidity measuring device control apparatus and a control apparatus can be reduced.

A fourth embodiment of the present invention will be described with reference to FIGS. Note that a description of the same configurations as in the first to third embodiments will be omitted.

In the fourth embodiment of the present invention, an intake air flow rate measuring device and a relative humidity detecting device are integrated into a single housing in the same housing. As shown in FIG. 11, an intake air flow rate detection element 115, a humidity detection element 27A, a temperature detection element 26B, an intake air temperature measurement element 109, a chip package connector 113, and a large-scale integrated circuit 116 are integrally resin-molded to form a chip package 114. Is forming. The chip package 114 is supported by the housing 101 by insert molding in the housing 101.

As shown in FIG. 10, the multifunctional intake air flow rate measuring device includes a connector 100, a housing 101, a housing support 102, a top cover 103, a front cover 105A, a back cover 105B, and a main air passage. A first bypass 106 that takes in a portion of the intake air flowing through 1, a second bypass 107 in which a relative humidity measuring element 27A and a temperature measuring element 26A are arranged, a chip package 114 that is insert-molded in the housing 101, And a lead frame 112 for electrical connection. The front cover 105A has an air intake port 107B for the second bypass 107, and detects the moisture content of the air taken in from the intake port 107B using the relative humidity measuring element 27A and the temperature measuring element 26A.

In the fourth embodiment of the present invention, the air flow measuring device and the relative humidity measuring device are integrated in the same housing, so that the environment to be measured is determined by the signal of the intake air flow measuring device 115 in the relative humidity measuring device. It is possible to know whether the gas in the atmosphere is exchanged. Therefore, as shown in FIG. 12, all the correction processes can be performed only in the relative humidity measuring device 22 without performing the measured atmosphere state grasping step 16 by the control device 21, and the control device 21 is conscious of the correction processing. The output value of the relative humidity measuring device 22 can be used without doing so.

A fifth embodiment of the present invention will be described with reference to FIGS. The description of the same configuration as that of the fourth embodiment is omitted.

The fifth embodiment of the present invention has a multi-functional configuration in which a pressure measuring device is integrally provided in the same housing in addition to an intake air flow rate measuring device and a relative humidity detecting device. As shown in FIG. 10, the pressure detection element 110 mounted on the control circuit board 111 is mounted at a location located outside the main air passage 1 of the housing 101. The housing 101 has a third bypass 108 communicating with the main air passage, and the pressure detecting element 101 measures the pressure of the air taken into the third bypass.

According to the fifth embodiment of the present invention, it is possible to appropriately set the pressures of the

mathematical formulas

1, 2 and 3 each time, and the pressure is set to 1 atm 101325 [Pa], which is more accurate than the case where a fixed value is used. Can be improved. The present technique is also effective when the atmospheric pressure changes during the execution of the correction process.

A sixth embodiment of the present invention will be described. Note that the description of the same configuration as in the second embodiment or the third embodiment is omitted.

In the sixth embodiment of the present invention, the absolute moisture amount used in the relative humidity estimated value calculation step ST8 is not the absolute moisture amount obtained in the absolute moisture amount calculation step ST4, but the temperature and relative humidity obtained in the measurement step ST7. It is set as the structure calculated every time using. As a result, the difference from the absolute water content when the previous characteristic diagnosis was performed can be made small, and the accuracy can be further improved.

DESCRIPTION OF SYMBOLS 1 Main air passage 2 Main air passage wall 3 Relative humidity measuring device mounting base 11 Housing support part 12 Screw hole 13 Connector 14 Housing 15 Cover 16 Main bypass 16A Main bypass A port 16B Main bypass B port 17 Sub bypass 17A Sub bypass A port 17B Sub-bypass B port 18 O-ring 21 Controller 22 Relative humidity measuring device 23 Relative humidity measuring device controller 24 Heating element drive unit 25 Heating element 26 Temperature 26A Temperature measuring element 26B Temperature signal processing unit 26C Temperature output unit 27 Relative humidity 27A Relative humidity measuring element 27B Relative humidity signal processing unit 27C Relative humidity output unit 28 Absolute moisture Amount 28B Absolute moisture amount calculation unit 28C Absolute moisture amount output unit 29A Characteristic diagnosis processing unit 29B Relative humidity correction amount calculation unit 30 Output characteristic 31 First measurement point 31A Measured value of relative humidity in state A 31B Relative humidity in state B Estimated value 32 Second measurement point 32A Measured value of relative humidity in state B 33 Ideal relative humidity output value 34 Characteristic deterioration amount 40 Relative humidity output characteristic 40A when characteristic deteriorates Reference point 40B when executing characteristic diagnosis step First diagnostic point 40C Second diagnostic point 41 Characteristic deterioration amount 42 when relative humidity of measured environment atmosphere is 0% Relative humidity output characteristic 43 incorporating first diagnostic point Relative humidity output after zero adjustment Characteristic 44 Output characteristic slope is 0, relative humidity Relative humidity output characteristics corrected for the entire area 100 Connector 101 Housing 102 Housing support 103 Top cover 104 O-ring 105A Front cover 105B Rear cover 106 First bypass 107 Second bypass 107B Inlet 108 Third bypass 109 Measurement of intake air temperature Element 110 Pressure measurement element 111 Control circuit board 112 Lead frame 113 Chip package connector 114 Chip package 115 Intake air flow rate measurement element 116 Large scale integrated circuit ST1 Measurement atmosphere state grasping step ST1 'Measurement atmosphere state grasping step ST2 Measurement environment atmosphere Replacement State Judgment Step ST2 'Measurement Environment Atmosphere Exchange State Determination Step ST3 Measurement step ST3A Temperature measurement step ST3B Relative humidity measurement step ST4 Absolute moisture content calculation step ST4 ′ Absolute moisture content calculation step ST5 Data acquisition step ST5 ′ Temperature control data acquisition step ST6 Temperature control step ST6 ′ Temperature control step ST7 Measurement Step ST7A Temperature measurement step ST7B Relative humidity measurement step ST8 Relative humidity estimation value calculation step ST8 ′ Relative humidity estimation value calculation step ST9 Relative humidity difference calculation step ST9 ′ Relative humidity difference calculation step ST10 Difference correction step ST11 Difference calculation frequency diagnosis step ST11 ′ Difference calculation frequency diagnosis step ST12 Characteristic deterioration amount calculation step ST12 ′ to be measured environment relative humidity 0% Characteristic deterioration amount calculation step ST13 of constant environment relative humidity 0% Characteristic deterioration amount correction step ST13 ′ Characteristic deterioration amount correction step ST14 Characteristic deterioration amount correction step ST14 ′ Characteristic deterioration amount correction step ST15 Correction processing continuation determination step ST15 ′ Correction processing continuation determination Step ST16 Measured atmosphere state grasping step ST17 Measured environment atmosphere exchange state determination step ST17 ′ Measured environment atmosphere exchange state determination step P1 Convergence point P1 ′ when correction processing is continued Processing point P2 when continuation of correction process Characteristic deterioration calculation process Time merging point P2 'Relative humidity difference calculation first time merging point P3 Completion processing end merging point P3' Compensation processing end merging point

Claims

In a humidity measuring device that calculates the absolute moisture content using a relative humidity signal and a temperature signal,
Using the absolute moisture content calculated in the first state and the temperature measured in the second state, an estimated value of the relative humidity in the second state is calculated, and the estimated value and the relative humidity measured in the second state are calculated. A characteristic diagnosis unit that calculates a characteristic deterioration amount in the second state by comparing the measured values;
A humidity measuring device comprising: a correction unit that corrects a measured value of relative humidity using the characteristic deterioration amount.
The characteristic diagnosis unit calculates characteristic deterioration amounts in a plurality of states,
The humidity measuring apparatus according to claim 1, wherein the correction unit corrects a measured value of relative humidity using the characteristic deterioration amounts in the plurality of states.
3. The humidity measuring apparatus according to claim 1, wherein the second state is changed from the first state by controlling a heat generation temperature of the heat generating portion.
The humidity measuring apparatus according to claim 2, wherein the correction unit corrects the output using an error characteristic obtained by a least square method.
The humidity measuring device according to any one of claims 1 to 4, wherein the characteristic diagnosis unit calculates the characteristic deterioration amount when it is determined that the gas in the ambient atmosphere to be measured is not in an exchanged state.
6. The humidity measuring apparatus according to claim 1, wherein the correction unit performs correction when the characteristic deterioration amount is a certain value or more.