Gas analyzer, gas analysis method, and program for gas analyzer

Abstract

The present invention facilitates determination of a replacement timing for a drying agent used in a gas analysis device and reduces the work associated with said determination, and moreover provides a gas analysis device 100 comprising a drying agent 7 that absorbs moisture included in sampled air, the gas analysis device 100 analyzing components in a gas being measured by using air that has passed through the drying agent 7, wherein the gas analysis device 100 comprises a sensor unit 10 that measures the temperature and / or humidity of the air before the air passes through the drying agent 7, and a moisture amount calculation unit 11 that calculates the amount of moisture absorbed by the drying agent 7 using the temperature and / or humidity measured by the sensor unit 10.

Description

[Technical field]

[0001] The present invention relates to a gas analyzer, a gas analysis method, and a program for the gas analyzer. [Background technology]

[0002] For example, NO contained in exhaust gas X As shown in Patent Document 1, there is a gas analyzer that uses a chemiluminescence method (CLD) to measure ozone. This gas analyzer using CLD is equipped with an ozone generator that generates ozone (O3) required for chemiluminescence inside the device. Since this ozone generator generates O3 from the air sampled as an ozone source separately from the exhaust gas sampling, the detection value of the CLD is affected by the reduction in the amount of ozone generated and quenching caused by moisture in the air.

[0003] For this reason, in gas analyzers using conventional CLDs, the air introduced into the ozone generator is passed through a desiccant such as silica gel to reduce the effect of moisture in the air. If the amount of moisture that this desiccant can absorb exceeds the allowable value, it will affect the detection value of the CLD, so maintenance such as replacing the desiccant is required before the amount of moisture that can be absorbed is exceeded. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-72032 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the gas analyzer is mounted on the vehicle, it is difficult to determine when to replace it (when to perform maintenance), because unlike bench tests where the temperature, humidity, and air pressure are controlled, the temperature, humidity, and air pressure in road tests vary greatly depending on the weather conditions at the time of the test, which in turn changes the amount of moisture in the air during the test, making it difficult to estimate the amount of moisture absorbed by the desiccant from the time of use.

[0006] In addition, users may remove the desiccant before and after the test and compare its weight before and after the test to infer whether it can be used for the next test or not. However, this raises the risk that the drying ability will be lost if the weather conditions for the next test change, and also makes the work before and after the test cumbersome.

[0007] Therefore, the present invention has been made to solve the above problems, and its main object is to make it easy to determine when maintenance such as replacement of a desiccant used in a gas analyzer is required, while reducing the work required to make that determination. [Means for solving the problem]

[0008] In other words, the gas analyzer of the present invention is a gas analyzer that has a desiccant that absorbs moisture contained in the air sampled as an ozone source, and analyzes the components in the gas to be measured using the air that has passed through the desiccant, and is characterized in that it has a sensor unit that measures at least one of the temperature and humidity of the air before it passes through the desiccant, and a moisture amount calculation unit that calculates the amount of moisture absorbed by the desiccant using at least one of the temperature and humidity measured by the sensor unit.

[0009] With this gas analyzer, the amount of moisture absorbed by the desiccant is calculated using at least one of the temperature and humidity measured by the sensor unit, making it possible to determine the remaining amount of moisture that the desiccant can absorb (allowable moisture amount), and easily predicting the timing of maintenance such as replacing the desiccant.In addition, since there is no need to measure the weight of the desiccant before and after testing as in the past, the work required to determine the timing of maintenance can be reduced.

[0010] It is preferable that the gas analyzer according to the present invention further comprises an output section that outputs the moisture amount calculated by the moisture amount calculation section and the allowable moisture amount set for the desiccant in a manner that allows comparison between them. With this configuration, it is easy to recognize the remaining amount of moisture that the desiccant can absorb, and it is easy to determine the timing for replacing the desiccant, etc.

[0011] Furthermore, it is desirable that the gas analyzer of the present invention further comprises an alarm unit that compares the moisture content calculated by the moisture content calculation unit with the allowable moisture content set for the desiccant and outputs an alarm indicating that the desiccant cannot be used based on the comparison result. With this configuration, the device automatically determines the timing for the desiccant, preventing errors in judgment due to subjective judgment by the user.

[0012] It is preferable that the notification unit outputs a pre-notification based on a result of the comparison as a preliminary step before outputting the alarm. With this configuration, the user can make changes to the test plan, prepare replacement desiccants, etc.

[0013] In order to make the effect of the present invention even more remarkable, it is desirable to use an analytical device that is mounted on a vehicle, where it is usually difficult to constantly monitor the analytical indications during road tests, and where the road tests are performed in an environment where the climatic conditions are likely to change. Since weather conditions are likely to change during road tests when the desiccant is mounted on a vehicle, the amount of moisture can be calculated using at least one of the temperature and humidity measured by the sensor unit, making it possible to accurately determine the amount of moisture remaining that the desiccant can absorb.

[0014] In order to accurately calculate the amount of moisture absorbed by the desiccant, it is preferable that the moisture amount calculation unit calculates the amount of moisture absorbed by the desiccant based on the following formula (1).

[0015]

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[0016] Further, a gas analysis method according to the present invention is a gas analysis method in which moisture contained in sampled air is absorbed and removed by a desiccant, and components in a measurement target gas are analyzed using the air that has passed through the desiccant, wherein at least one of the temperature and humidity of the air before passing through the desiccant is Calculate The method is characterized in that the amount of moisture absorbed by the desiccant is calculated using at least one of the measured temperature and humidity.

[0017] Furthermore, the program for a gas analyzer of the present invention is a program used in a gas analyzer that absorbs and removes moisture contained in sampled air using a desiccant and analyzes the components in a gas to be measured using the air that has passed through the desiccant, and is characterized in that it has a computer equipped with the functions of an acquisition unit that acquires at least one of the temperature and humidity of the air before it passes through the desiccant, and a moisture amount calculation unit that calculates the amount of moisture absorbed by the desiccant using at least one of the temperature and humidity acquired by the acquisition unit. Effect of the Invention

[0018] According to the present invention as described above, it is possible to easily determine the timing for replacing a desiccant used in a gas analyzer and to reduce the work involved in making such a determination. [Brief description of the drawings]

[0019] [Figure 1] 1 is an overall schematic diagram of a gas analyzer according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a functional block diagram of the control device according to the embodiment. [Diagram 3] FIG. 2 is a schematic diagram showing a display screen of the embodiment. [Figure 4] FIG. 13 is a schematic diagram showing a modified example of the display screen. [Explanation of symbols]

[0020] 100 Gas analyzer 7. Desiccant 10. Sensor section 11. Moisture content calculation section 13 Output section 15. Notification Department DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A gas analyzer 100 according to one embodiment of the present invention will now be described with reference to the drawings.

[0022] <Device configuration> The gas analyzer 100 of this embodiment is, for example, an on-board type that is mounted on a vehicle and analyzes components in exhaust gas discharged from the vehicle during a road test. Examples of the vehicle include an engine vehicle, a hybrid vehicle, and a plug-in hybrid vehicle.

[0023] Specifically, the gas analyzer 100 detects nitrogen oxides (NO X The gas analyzer 100 may also include an analyzer using a non-dispersive infrared (NDIR) method, an analyzer using a flame ionization (FID) method, or a condensation particle counter (CPC).

[0024] As shown in FIG. 1, the gas analyzer 100 includes an exhaust gas flow path 2 through which sampled exhaust gas flows, a CLD detector 3 provided in the exhaust gas flow path 2 for detecting NO in the exhaust gas, an ozone gas inlet path 4 for introducing ozone gas (O3) into the CLD detector 3, an ozone generator 5 provided in the ozone gas inlet path 4 for generating ozone gas from the atmosphere, an air inlet path 6 for introducing the atmosphere into the ozone generator 5, and a desiccant 7 such as silica gel provided in the air inlet path 6 for absorbing moisture from the atmosphere.

[0025] The exhaust gas flow path 2 is provided with a NO 2 catalyst that reduces NO2 contained in the sampled exhaust gas to NO. X Converter 8 is provided. This NO X As the exhaust gas passes through the converter 8, NO2 is reduced to NO, and the NO X (NO+NO2) is detected, and NO X It is possible to measure the concentration of

[0026] In addition, the exhaust gas flow path 2 contains NO XA bypass passage 21 that bypasses the converter 8 is provided, and by passing exhaust gas through this bypass passage 21, NO is detected by the CLD detector 3, and the concentration of NO can be measured. X Since the concentration of NO and the concentration of NO can be measured, the concentration of NO2 can also be measured by calculating the difference between them. In addition, an ozone decomposer 9 for decomposing ozone gas is provided downstream of the CLD detector 3 in the exhaust gas flow path 2.

[0027] The CLD detector 3 is equipped with a reactor into which exhaust gas from the exhaust gas flow path 2 and ozone gas from the ozone gas inlet path 4 are introduced, and an oxidation reaction of NO by ozone gas occurs in the reactor. Some of the NO2 produced at this time becomes excited, and the excitation energy when returning from this excited state to the ground state is released as a photon. This phenomenon is called chemiluminescence. The NO concentration in the sample gas can be measured by detecting the emission intensity of this chemiluminescence with a photoelectric element.

[0028] As shown in Figures 1 and 2, the gas analysis device 100 of this embodiment is equipped with a sensor unit 10 that measures the temperature, humidity, and air pressure of the air before it passes through the desiccant 7, and a moisture amount calculation unit 11 that calculates the amount of moisture absorbed by the desiccant 7 using at least one of the temperature and humidity measured by the sensor unit 10.

[0029] The sensor unit 10 has a temperature sensor 10a that measures the temperature of the air before it passes through the desiccant 7, a humidity sensor 10b that measures the relative humidity of the air before it passes through the desiccant 7, and an air pressure sensor 10c that measures the air pressure of the air before it passes through the desiccant 7. These sensors 10a, 10b, and 10c continuously measure the temperature, relative humidity, and air pressure around the gas analyzer 100. Note that a temperature sensor, a humidity sensor, and an air pressure sensor mounted on a vehicle may be used as the sensor unit 10.

[0030] 2, the function of the moisture content calculation unit 11 is fulfilled by a control device COM of the gas analyzer 100. The control device COM is a dedicated or general-purpose computer having a CPU, an internal memory, an input / output interface, an AD converter, etc. The control device COM also includes a data acquisition unit 12 that acquires temperature data, humidity data, and air pressure data from the sensor unit 10.

[0031] Specifically, the moisture amount calculation unit 11 calculates the amount of moisture absorbed by the desiccant 7 based on the following formula (1).

[0032]

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[0033] If the temperature at a certain moment is T1 (℃) and the relative humidity is RH1 (%), the amount of moisture per unit volume contained in the air at that time is w1 (g / cm 3 ) is the amount of saturated water vapor at T1, a(T1) (g / cm 3 ) is expressed by the following formula:

[0034]

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[0035] Sampling flow rate L (cm) of air flowing through the air inlet 6 3 / sec) is a constant value by design. Thus, the weight W1 (g / sec) of water per unit time sucked by gas analyzer 100 at a given moment is expressed by the following formula:

[0036]

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[0037] From the above, the total amount of moisture W(g) absorbed by the desiccant 7 from the atmosphere during the measurement time t(sec) of the gas analyzer 100 can be calculated by the following formula.

[0038]

number

[0039] The amount of moisture that can be absorbed by the desiccant 7 (allowable moisture amount) W silica can be set by the user based on the weight of the desiccant 7 and the manufacturer's specifications.

[0040] The control device COM of this embodiment calculates the moisture amount W calculated by the moisture amount calculation unit 11 and the allowable moisture amount W set in the desiccant 7. silica The gas analyzer 100 further includes an output section 13 that outputs the above-mentioned values ​​in a manner that allows comparison between the above-mentioned values. The function of the output section 13 is exerted by a control device COM of the gas analyzer 100.

[0041] As shown in FIG. 3, the output unit 13 of this embodiment outputs the calculated moisture amount W and the allowable moisture amount W silica The vertical axis of the graph G1 represents the amount of moisture (g) and the horizontal axis represents the elapsed time. In addition, the output unit 13 also displays the allowable moisture amount W silica The ratio (%) of the calculated water content W to the total water content W may be displayed on the display 13.

[0042] Alternatively, the output unit 13 may display a graph G2 in which the vertical axis represents the remaining water retaining capacity (g) of the desiccant 7 and the horizontal axis represents the elapsed time, as shown in FIG. 4, or a graph G3 in which the vertical axis represents the allowable water retaining capacity W silica It is also possible to display the graph as a percentage normalized by (W / W silica ) × 100(%).

[0043] In addition, the gas analyzer 100 calculates the moisture amount W calculated by the moisture amount calculation unit 11 and the allowable moisture amount W set in the desiccant 7. silica The gas analyzer 100 may further include an alarm unit 15 that compares the moisture content W with the allowable moisture content W and outputs an alarm indicating that the desiccant 7 cannot be used based on the comparison result. The function of this alarm unit 15 is exercised by the control device COM of the gas analyzer 100. silica In other words, the notification unit 15 notifies the user that the calculated moisture content W is equal to or exceeds the allowable moisture content W. silica reaches, an alarm is output to indicate that the desiccant 7 cannot be used. Possible modes for outputting the alarm include displaying alarm information (e.g., a warning message) on the display 14, or changing the display mode of an icon for starting an application that displays the graph G.

[0044] Furthermore, the notification unit 15 notifies the calculated moisture amount W and the allowable moisture amount W silica Based on the result of the comparison with the water content W, a pre-caution notice may be output as a step before an alarm is output. For example, if the calculated water content W is less than the allowable water content W silica When the graph G reaches X% (e.g., 80%) of the graph G, a pre-notification may be output. Here, the pre-notification may be output by displaying pre-notification information (e.g., a pre-notification message) on the display 14 or by changing the display mode of an icon for starting an application for displaying the graph G.

[0045] In addition, the notification unit 15 notifies the calculated moisture content W and the allowable moisture content W silicaBased on the result of the comparison with the remaining amount of moisture that the desiccant 7 can absorb, the remaining usable time of the desiccant 7 may be estimated and the usable time may be notified to the user. silica It is possible to determine the moisture content W from the temperature and humidity measured by the sensor, the atmospheric pressure, other usage patterns, and past usage records (the slope of the graph of the calculated moisture content W), etc.

[0046] <Effects of this embodiment> According to the gas analyzer 100 of the present embodiment configured as described above, the amount of moisture W absorbed by the desiccant 7 is calculated using at least one of the temperature and humidity measured by the sensor unit 10. Therefore, the remaining amount of moisture that the desiccant 7 can absorb (W silica -W), it becomes possible to easily determine the timing of maintenance such as replacing the desiccant 7. In addition, since it is no longer necessary to measure the weight of the desiccant 7 before and after the test as in the conventional method, the work required to determine the timing of maintenance can be reduced.

[0047] <Other embodiments> The present invention is not limited to the above-described embodiment.

[0048] For example, in the above embodiment, the sensor unit measures the temperature, humidity, and air pressure, and calculates the amount of moisture absorbed by the desiccant using the measured temperature, humidity, and air pressure. However, the sensor unit may measure one of the temperature, humidity, or air pressure, and set the other of the temperature, humidity, or air pressure as a set value, from which the amount of moisture absorbed by the desiccant may be calculated.

[0049] In the above embodiment, ozone generated from the air that has passed through the desiccant 7 is used to measure nitrogen oxides (NO X ) concentration, but the present invention may be applied to other gas analyzers that analyze the components in the measurement target gas (e.g., any component such as CO, CO2, or NO) using air that has passed through the desiccant 7.

[0050] Also, air that has passed through the desiccant 7 may be used as the dilution gas. In this case, components in the measurement target gas include, for example, particulate matter (PM) and solid particle number (PN). When using to measure the solid particle number, a part of the sampled exhaust gas may be filtered through a particle collection filter, and the gas from which floating solid particles have been removed may be further passed through a desiccant to be used as the dilution gas.

[0051] In addition, various modifications and combinations of the embodiments may be made without departing from the spirit of the present invention. [Industrial Applicability]

[0052] According to the present invention, it is possible to easily determine the timing for replacing a desiccant used in a gas analyzer and to reduce the work involved in making such a determination.

Claims

1. A gas analyzer that includes a desiccant that absorbs moisture contained in sampled air, and analyzes components in a measurement target gas using the air that has passed through the desiccant, a sensor unit that measures at least one of a temperature and a humidity of the air before the air passes through the desiccant; a moisture amount calculation unit that calculates an amount of moisture absorbed by the desiccant using at least one of the temperature and the humidity measured by the sensor unit; an output section that outputs the moisture amount calculated by the moisture amount calculation section and an allowable moisture amount set for the desiccant in a manner that allows comparison thereof.

2. A gas analyzer comprising a desiccant that absorbs moisture contained in sampled air, and that analyzes components in a gas to be measured using the air that has passed through the desiccant, a sensor unit that measures at least one of a temperature and a humidity of the air before the air passes through the desiccant; a moisture amount calculation unit that calculates an amount of moisture absorbed by the desiccant using at least one of the temperature and the humidity measured by the sensor unit; and an alarm unit that compares the moisture amount calculated by the moisture amount calculation unit with an allowable moisture amount set for the desiccant, and outputs an alarm indicating that the desiccant cannot be used based on a result of the comparison.

3. The gas analyzer according to claim 2 , wherein the notification unit outputs a pre-notification based on the result of the comparison as a preliminary step before outputting the alarm.

4. 4. The gas analyzer according to claim 1, which is mounted on a vehicle and analyzes components in exhaust gas discharged from the vehicle.

5. 5. The gas analyzer according to claim 1, wherein the moisture amount calculation unit calculates the amount of moisture absorbed by the desiccant based on the following formula (1): [0010] where W is the amount of water absorbed by the desiccant (g) and L is the air sampling flow rate (cm ３ / sec), and a(T ｘ ) is the amount of saturated water vapor (g / cm) at the temperature Tx measured by the sensor unit. ３ ) and RH ｘ is the relative humidity (%) measured by the sensor unit.

6. A gas analysis method for analyzing components in a measurement target gas by using a desiccant to absorb moisture contained in sampled air and the air that has passed through the desiccant, comprising: measuring at least one of a temperature and a humidity of the air before passing through the desiccant; Calculating the amount of moisture absorbed by the desiccant using at least one of the measured temperature and humidity; A gas analysis method that enables a comparison of the calculated moisture content with an allowable moisture content set for the desiccant.

7. A program used in a gas analyzer that absorbs moisture contained in sampled air using a desiccant and analyzes components in a measurement target gas using the air that has passed through the desiccant, an acquisition unit that acquires at least one of a temperature and a humidity of the air before the air passes through the desiccant; a moisture amount calculation unit that calculates an amount of moisture absorbed by the desiccant using at least one of the temperature and the humidity acquired by the acquisition unit; an output unit that outputs the moisture amount calculated by the moisture amount calculation unit and the allowable moisture amount set for the desiccant in a manner that allows comparison; A program for a gas analyzer, comprising: a program for causing a computer to function as a gas analyzer;

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