WO2023276762A1 - Gas analyzer calibration method, gas analyzer pressure correcting method, gas analyzer inspection method, pressure variation method, pressure variation apparatus, and gas analysis system - Google Patents

Abstract

The present invention enables accurate calculation of a pressure correction coefficient while reproducing the pressurized state in a gas analyzer, and involves: connecting, to a sample gas introduction port P1 and a gas discharge port P2 of a gas analyzer 2, a pressure variation apparatus 3 having a pressurizing mechanism 31 and a gas discharge mechanism 32; varying the pressure at the sample gas introduction port P1 and at the gas discharge port P2 by the pressurizing mechanism 31 of the pressure variation apparatus 3; introducing, in the pressure varied state, a calibration gas from a calibration gas introduction port P0 of the gas analyzer 2, and causing the calibration gas flowing out of the sample gas introduction port P1 or the gas discharge port P2 to be discharged by means of the gas discharge mechanism 32 of the pressure variation apparatus 3; and calculating the pressure correction coefficient of the gas analyzer 2 by using measurement results of the gas analyzer 3 on the calibration gas.

Description

Gas analyzer calibration method, gas analyzer pressure correction method, gas analyzer inspection method, pressure fluctuation method, pressure fluctuation device, and gas analysis system

The present invention relates to a gas analyzer calibration method, a gas analyzer pressure correction method, a gas analyzer inspection method, a pressure fluctuation method, a pressure fluctuation device, and a gas analysis system.

2. Description of the Related Art In recent years, vehicle-mounted exhaust gas analyzers have been used for component analysis and vehicle testing of exhaust gases emitted from vehicles running on roads. This exhaust gas analyzer has an analyzer for analyzing components such as nitrogen oxides (NO _x ), carbon monoxide (CO) and carbon dioxide (CO ₂ ).

　In each analyzer installed in this exhaust gas analyzer, the measured values are affected by pressure fluctuations caused by changes in altitude and other factors while driving on the road. Therefore, the exhaust gas analyzer uses a pressure correction coefficient for correcting the pressure influence to perform pressure correction on the measured value of each analyzer and convert it to a reference pressure (for example, the pressure when creating a calibration curve). Each component concentration is calculated.

And, as a method for obtaining the pressure correction coefficient used in this exhaust gas analyzer, there is a method for calibrating a gas analyzer disclosed in Patent Document 1. In this gas analyzer calibration method, a pressure variation device is connected to the sample gas introduction port and the gas discharge port, the sample gas introduction port and the gas discharge port are decompressed by the pressure variation device, and the calibration gas is introduced in the decompressed state. A calibration gas is introduced from the port, and the measurement results of the calibration gas are used to calculate the pressure correction coefficient of the gas analyzer. At this time, the exhaust gas analyzer is operated in the same operating state as when it is mounted on the vehicle, that is, the exhaust pump is operating to keep the calibration gas flowing to each analyzer and various sensors are operating.

JP 2019-86371 A

However, when using the pressure correction factor obtained using the calibration method of the gas analyzer described above, the measurement results at altitudes lower than the calibration point are considered to have the same pressure effect even at altitudes lower than the calibration point. Since the correction is extrapolated based on assumptions, there is a risk that there will be discrepancies between the actual measurement results and those at low altitudes.

In addition, in Patent Document 1, the sample gas introduction port and the gas discharge port are pressurized, and in the pressurized state, the calibration gas is introduced from the calibration gas introduction port, and the measurement result of the calibration gas is used to Calculation of the pressure correction coefficient of the analyzer is also described, but no specific configuration is disclosed.

Therefore, in order to calibrate the gas analyzer in a pressurized state, as described in Prior Document 1, it is necessary to bring the exhaust gas analyzer into the pressurized test room for calibration work.

Therefore, the present invention has been made to solve the above-mentioned problems, and the pressure correction coefficient can be calculated while reproducing the state of pressurization for the gas analyzer without preparing an environmental facility such as a pressurization test chamber. The main task is to find it with high accuracy.

That is, in the method for calibrating a gas analyzer according to the present invention, a pressure fluctuation device having a pressurization mechanism and a gas discharge mechanism is connected to a sample gas introduction port and a gas discharge port of the gas analyzer, A pressure mechanism applies pressure to the sample gas introduction port and the gas discharge port to vary the pressures of the sample gas introduction port and the gas discharge port, and the state in which the pressure is changed (specifically, the pressure In a state where pressure is applied compared to before the pressure mechanism is operated), calibration gas is introduced from the calibration gas introduction port of the gas analyzer and flows out from the sample gas introduction port or the gas discharge port. Gas is discharged by the gas discharge mechanism of the pressure fluctuation device, and the pressure correction coefficient of the gas analysis device is calculated using the measurement result of the calibration gas in the gas analysis device.

According to the present invention, since the pressure fluctuation device is connected to the sample gas introduction port and the gas discharge port of the gas analyzer, the pressurized state of the gas analyzer can be reproduced without using a pressurization test chamber. can do. Therefore, at altitudes lower than the calibration point, the pressure correction coefficient can be obtained with high accuracy without extrapolative correction of the pressure correction coefficient.

In addition, in order to obtain the pressure correction coefficient with high accuracy, the pressure variation device is used to vary a plurality of pressures, and the measurement results of the calibration gas at each of the plurality of pressures match the measurement results of the calibration gas at the reference pressure. It is desirable to calculate the pressure correction factor of the gas analyzer as follows. As the reference pressure, the pressure at the time of preparing the calibration curve of the gas analyzer or the pressure at the time of calibration such as zero calibration or span calibration can be considered.

It is desirable to introduce an excessive amount of the calibration gas from the calibration gas introduction port and measure the calibration gas while allowing the calibration gas to overflow from the sample gas introduction port. With this configuration, the calibration gas can be introduced into the analyzer of the gas analyzer without being diluted.

Some conventional gas analyzers are further equipped with an atmosphere introduction port. Here, it is conceivable that the air introduced from the air introduction port is used to dilute the gas or generate ozone. Ozone generated from the atmosphere is used for the measurement of the analyzer. The analyzer in this case is considered to be a nitrogen oxide analyzer of the chemiluminescence (CLD) method using an oxidation reaction by ozone gas.
Even in this case, there is a risk that the measurement results of the gas analyzer will be affected by pressure fluctuations through the atmosphere introduction port. Therefore, in the calibration method of the gas analyzer of the present invention, the pump is connected to the atmosphere introduction port, pressure is applied to the sample gas introduction port, the gas discharge port and the atmosphere introduction port, and the sample gas is introduced. It is desirable to vary the pressure of the port, the gas exhaust port and the atmospheric inlet port.
At this time, since the calibration gas is discharged by the gas discharge mechanism of the pressure fluctuation device, backflow of the calibration gas at the atmosphere introduction port can be suppressed.

If the gas analyzer is of a vehicle-mounted type, the effects of the present invention can be made remarkable because air pressure fluctuations are likely to occur depending on the travel route in the actual road test.

Further, the pressure correction method for a gas analyzer according to the present invention uses the pressure correction coefficient obtained by the above calibration method to convert the measurement result of the actual measurement of the gas analyzer based on the pressure at the time of the actual measurement. and correcting the measurement result at the reference pressure of the gas analyzer.

Further, a method for inspecting a gas analyzer according to the present invention is a gas analyzer having a pressure correction function using a pressure correction coefficient. The device is connected, and the pressurizing mechanism of the pressure variation device applies pressure to the sample gas introduction port and the gas discharge port to vary the pressures of the sample gas introduction port and the gas discharge port, and the pressure changes. In a changed state (specifically, a state in which pressure is applied compared to before the pressurization mechanism operates), while introducing a calibration gas from a calibration gas introduction port of the gas analyzer, the sample The calibration gas flowing out from the gas introduction port or the gas discharge port is discharged by the gas discharge mechanism of the pressure fluctuation device, and the measured value after correction using the pressure correction coefficient in the gas analysis device and the calibration gas is compared with a known concentration at a reference pressure of

Further, in the pressure fluctuation method according to the present invention, a pressure fluctuation device having a pressurization mechanism and a gas discharge mechanism is connected to a sample gas introduction port and a gas discharge port of a gas analyzer, and the pressure fluctuation device of the pressure fluctuation device is connected to the gas discharge port. applies pressure to the sample gas introduction port and the gas discharge port to vary the pressure of the sample gas introduction port and the gas discharge port to vary the pressure of the gas analyzer, and the sample gas introduction port Alternatively, the gas flowing out from the gas discharge port is discharged by the gas discharge mechanism of the pressure fluctuation device.

Further, a pressure fluctuation device according to the present invention is a pressure fluctuation device for fluctuating the pressure of a gas analyzer, comprising: a first channel connected to a sample gas introduction port of the gas analyzer; A second flow path connected to a gas discharge port, and applying pressure to the sample gas introduction port and the gas discharge port through the first flow path and the second flow path to remove the sample gas introduction port and the gas discharge port. connected to a pressure mechanism for varying the pressure of the gas discharge port, a flow path between the pressure mechanism and the sample gas introduction port, and a flow path between the pressure mechanism and the gas discharge port; and a gas discharge mechanism for discharging gas flowing out from the sample gas introduction port or the gas discharge port.

In order to reproduce the state of pressurization of the gas analyzer through the first flow path and the second flow path by a common pressurization source, the pressurization mechanism should include the first flow path and the second flow path. It is desirable to have a confluence channel to which the flow paths are connected, and a pressurization source that pressurizes the first flow path and the second flow path via the confluence flow path. Here, in order to easily adjust the pressure of each channel, it is desirable that the pressurizing mechanism has a pressure adjusting section that adjusts the pressure of the merged channel.

As a specific embodiment of the pressurization mechanism, the confluence flow path has a buffer tank, the pressurization source is a pump, and the first flow path and the second flow path are buffer tanks. It is desirable to be connected to the pump through a tank. Here, since the first channel and the second channel are connected to the pump through the buffer tank, it is possible to reproduce the pressurized state of the gas analyzer while reducing the pulsation of the pump. .

As an apparatus configuration capable of putting the gas analysis apparatus into a pressure-reduced state as well as a pressurized state, the pressure fluctuation device is configured such that the sample gas is introduced through the first flow path and the second flow path. It is desirable to further include a decompression mechanism for decompressing the port and the gas discharge port, and a switching mechanism for switching between a pressurized state by the pressurization mechanism and a decompressed state by the decompression mechanism.

It is desirable that the pressure fluctuation device of the present invention further include a control section that controls the switching mechanism to automatically switch between the pressurized state and the depressurized state.

In order to simplify the device configuration by sharing the configurations of the gas discharge mechanism and the decompression mechanism, the gas discharge mechanism has a suction pump, and the decompression mechanism is configured using the suction pump. It is desirable to be

As mentioned above, some gas analyzers have an air introduction port. In this case, the pressure fluctuation device further includes a third flow path connected to the atmosphere introduction port of the gas analyzer, and the pressurizing mechanism supplies pressure to the atmosphere introduction port via the third flow path. is added to change the pressure of the atmosphere introduction port.

Furthermore, a gas analysis system according to the present invention is characterized by comprising a gas analysis device for analyzing a component to be measured in a sample gas, and the pressure fluctuation device described above.

According to the present invention described above, it is possible to obtain the pressure correction coefficient with high accuracy while reproducing the state of pressurization for the gas analyzer.

1 is an overall schematic diagram of an exhaust gas analysis system according to an embodiment of the present invention; FIG. FIG. 4 is a schematic diagram showing the flow of air from the air introduction port of the exhaust gas analysis system according to the same embodiment. FIG. 4 is a schematic diagram showing the flow of air from the air introduction port of the exhaust gas analysis system according to the same embodiment. It is a figure which shows the flowchart of the calibration method of the same embodiment. FIG. 4 is a schematic diagram showing the configuration of a pressure variation device according to a modified embodiment; FIG. 4 is a schematic diagram showing the configuration of a pressure variation device according to a modified embodiment; FIG. 4 is a schematic diagram showing the configuration of a pressure variation device according to a modified embodiment; FIG. 3 is an overall schematic diagram of an exhaust gas analysis system of a modified embodiment;

An exhaust gas analysis system 100 according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the exhaust gas analysis system 100 of the present embodiment includes a vehicle-mounted exhaust gas analyzer 2 mounted on a vehicle, and a pressure correction coefficient of the exhaust gas analyzer 2 connected to the exhaust gas analyzer 2. and a pressure fluctuation device 3 used when obtaining the pressure.

In addition, although not shown, the exhaust gas analysis system 100 includes an exhaust gas sampling mechanism such as a sampling pipe for sampling all or part of exhaust gas discharged from an exhaust pipe connected to an internal combustion engine (engine) of a vehicle, and the exhaust gas sampling mechanism. It is equipped with a heating tube for introducing the exhaust gas collected by the mechanism into the exhaust gas analyzer 2 while heating or maintaining it at a predetermined temperature, and a power supply for supplying power to the exhaust gas analyzer 2 and the heating tube.

<Exhaust gas analyzer 2>
The exhaust gas analyzer 2 detects components to be measured, such as carbon monoxide (CO), carbon dioxide (CO ₂ ), nitrogen oxides (NO _x ), methane (CH ₄ ), total hydrocarbons (THC), etc., in the exhaust gas. In this embodiment, a CO/CO ₂ analyzer 21 , an NO _X analyzer 22 and an NO analyzer 23 are provided.

The CO/CO ₂ analyzer 21 continuously measures the concentration of carbon monoxide or carbon dioxide contained in the exhaust gas by a non-dispersive infrared absorption (NDIR) method. The NO _X analyzer 22 continuously measures the concentration of NO _X in the exhaust gas by a chemiluminescence (CLD) method (chemiluminescence method). The NO analyzer 23, like the NO _X analyzer 22, continuously measures the NO concentration in the exhaust gas by the CLD method. In addition, the exhaust gas analyzer 2 can be equipped with various analyzers depending on the component to be measured. For example, when measuring methane (CH ₄ ) and total hydrocarbons (THC), an analyzer using a flame ionization (FID) method is provided. A condensation particle counter (CPC) is also provided for measuring the number of solid particles (PN) in the exhaust gas. The analysis data obtained by these analyzers 21 to 23 are output to the information processing section 4, and the analysis data are processed, recorded, or displayed by the information processing section 4. FIG. Also, the plurality of analyzers may be provided separately.

Here, the information processing unit 4 is a dedicated or general-purpose computer having a CPU, an internal memory, an AD converter, an input/output inverter, etc., and not only analyzes data from the analyzers 21 to 23, but also receives data from other sensors. Acquire and process, record or display data. Here, the sensor group includes an air-fuel ratio sensor that measures the air-fuel ratio (A/F) of the vehicle, a flow meter that measures the flow rate of the exhaust gas discharged from the exhaust pipe, a GPS sensor that detects the position of the vehicle, and a sensor outside the vehicle. They include a temperature sensor that measures temperature, a humidity sensor that measures humidity outside the vehicle, and a pressure sensor that measures pressure (atmospheric pressure) outside the vehicle.

Then, in the exhaust gas analyzer 2, a sample gas introduction port P1 for introducing the exhaust gas to the CO/CO ₂ analyzer 21, the NO _X analyzer 22 and the NO analyzer 23, and the analyzers 21 to 23. A gas discharge port P2 for discharging exhaust gas and the like is provided. The exhaust gas analyzer 2 also includes an ozone generator 24 that generates ozone gas used in the NO _X analyzer 22 and the NO analyzer 23, and an air introduction port P3 for introducing air into the ozone generator 24. is provided. That is, in the present embodiment, the ports exposed to the atmosphere and affected by atmospheric pressure fluctuations are the sample gas introduction port P1, the gas discharge port P2, and the atmosphere introduction port P3.

The sample gas introduction port P1 is connected to the upstream end of the main flow path L1 through which the exhaust gas flows, and the main flow path L1 is provided with a CO/CO ₂ analyzer 21, an NO _X analyzer 22 and an NO analyzer 23. ing. A gas discharge port P2 is connected to the downstream end of the main flow path L1.

A suction pump 25 is provided downstream of the CO/CO ₂ analyzer 21, the NO _X analyzer 22, and the NO analyzer 23 in the main flow path L1. The exhaust gas is sampled by the exhaust gas sampling mechanism by the suction pump 25, introduced into the main flow path L1 from the sample gas introduction port P1, and measured by the analyzers 21-23. The suction pump 25 allows the CO/CO ₂ analyzer 21, NO _X analyzer 22 and NO analyzer 23 to perform analysis under reduced pressure conditions.

The main flow path L1 of the present embodiment branches into flow paths L11 to L13 corresponding to the analyzers 21 to 23, and the analyzers 21 to 23 are connected in parallel. merges upstream of Constant flow rate devices CP1-CP3 such as capillaries are provided in the branch paths L11-L13 to keep the flow rate of the exhaust gas flowing into the analyzers 21-23 constant. Here, in the main flow path L1, the flow path from the sample gas introduction port P1 to the CO/CO ₂ analyzer 21 and the CO/CO ₂ analyzer 21 are heated to a predetermined temperature by the heating block 26 so that moisture in the exhaust gas does not condense. (eg 95° C.). A converter catalyst 27 that converts NO _X to NO is provided upstream of the NO _X analyzer 22 in the branch L12 where the NO _X analyzer 22 is provided. is heated to a predetermined temperature (for example, 210° C.).

A calibration gas flow path L2 having a calibration gas introduction port P0 for introducing a calibration gas having a known concentration is connected to the upstream side of each analyzer 21 to 23 in the main flow path L1 (upstream side of the branch point). there is The calibration gas flow path L2 is connected to a calibration gas cylinder (not shown). Further, the calibration gas flow path L2 is provided with an electromagnetic on-off valve V1 for switching supply/stop of the calibration gas to the main flow path L1. The electromagnetic on-off valve V1 is controlled by the valve control section of the information processing section 4. As shown in FIG.

The air introduction port P3 is connected to the upstream end of the air introduction flow path L3, and the downstream end of the air introduction flow path L3 is connected to the ozone generator 24. As shown in FIG. The ozone gas generated by the ozone generator 24 is introduced into the NO _X analyzer 22 and the NO analyzer 23 through the ozone gas flow path L4 connecting the ozone generator 24 and the NO _X analyzer 22 and the NO analyzer 23, respectively. be done.

As shown in FIG. 2, the ozone gas flow path L4 is provided with a constant flow device CP4 such as a capillary for making the flow rate of the ozone gas constant. Further, in the atmosphere introduction passage L3, there is a branch flow that introduces the atmosphere to the downstream side of the heating block 26 and the upstream side of the NO _X analyzer 22 and the NO analyzer 23 in the main passage L1 to dilute the exhaust gas. path L5 is connected. A constant flow device CP5 such as a capillary is provided in the branch flow path L5 to keep the air flow constant. The pressure of the ozone generator 24 is adjusted by the pressure regulating valve V2 to a predetermined pressure so as to be the first pressure (eg -20 kPa) with respect to the pressure of the atmosphere introduction port P3, and the pressures of the analyzers 22 and 23 are controlled by electromagnetic proportionality. A second pressure (eg, -40 kPa) is adjusted to a predetermined pressure with respect to the pressure of the atmosphere introduction port P3 by the valve V3 and the constant flow device CP4. Further, the pressure on the downstream side (analyzers 22, 23) of the constant flow device CP2 is set to a second pressure (for example, -40 kPa) with respect to the pressure of the atmosphere introduction port P3 by the electromagnetic proportional valve V3 and the constant flow device CP5. is adjusted to a predetermined pressure. In this manner, a constant flow rate of ozone gas is supplied to the analyzers 22 and 23, and a constant flow rate of dilution air is supplied to the main flow path L1.

In addition, as shown in FIG. 3, the atmosphere introduction passage L3 also has a constant flow rate function for causing a constant flow rate of the exhaust gas to flow to the NO _X analyzer 22 and the NO analyzer 23 . Specifically, a connection flow path L6 connected to the downstream side of the NO _X analyzer 22 and the NO analyzer 23 and the upstream side of the suction pump 25 in the main flow path L1 is connected to the atmosphere introduction flow path L3. It is The connection channel L6 of the present embodiment is a common channel with a part of the branch channel L13. A pressure regulating valve V2 is provided on the upstream side of the connection point of the connection flow path L6 in the atmosphere introduction flow path L3 (upstream of the constant flow device CP1). A solenoid proportional valve V3 is provided in a bypass flow path L7 connecting the . The pressure regulating valve V2 refers to the input pressure on the upstream side of the constant flow device CP2 in the main flow path L1, and adjusts the input pressure to a first pressure (eg, -20 kPa) to a predetermined pressure. is. Further, the proportional solenoid valve V3 refers to the input pressure on the upstream side of the constant flow device CP2 in the main flow path L1 and the output pressure on the downstream side of the proportional solenoid valve V3 in the connection path L6, side output pressure (buffer tank BT pressure) is adjusted to a predetermined pressure so as to be a second pressure (for example, -40 kPa) with respect to the input pressure. That is, the pressure in the buffer tank BT is reduced to a predetermined pressure by the pressure regulating valve V2 and the constant flow device CP1 so as to become a second pressure (eg, -40 kPa) with respect to the pressure in the atmosphere introduction port P3. In this way, the differential pressure between the upstream pressure and the downstream pressure of the constant flow devices CP1 to CP3 provided in each of the branch paths L11 to L13 is kept constant (-20 kPa) by the pressure regulating valve V2 and the electromagnetic proportional valve V3. , the CO/CO ₂ analyzer 21 , the NO _X analyzer 21 and the NO analyzer 22 at a constant flow rate. Any one of the pressure regulating valve V2 and the electromagnetic proportional valve V3 may be provided. Also, the pressure control valve V2 may be replaced with an electromagnetic proportional valve.

<Pressure fluctuation device 3>
The pressure fluctuation device 3 is used when calibrating the exhaust gas analyzer 2 described above, specifically when determining the pressure correction coefficient of the exhaust gas analyzer 2 . Note that the pressure correction coefficients of the present embodiment are the CO concentration obtained by the CO/CO ₂ analyzer 21, a coefficient for correcting pressure fluctuations in the CO ₂ concentration, and pressure fluctuations in the NO _X concentration obtained by the NO _X analyzer 22. A correction coefficient is a coefficient for correcting pressure fluctuations of the NO concentration obtained by the NO analyzer 23 . Specifically, the pressure correction coefficients are coefficients for converting these concentrations into reference pressures (in this embodiment, the pressure at the time of preparing the calibration curve).

This pressure fluctuation device 3 pressurizes a plurality of ports P1 to P3 of the exhaust gas analyzer 2 that are open to the atmosphere.

Specifically, as shown in FIGS. 1 to 3, the pressure fluctuation device 3 has a first flow path 3L1, one end of which is connected to the sample gas introduction port P1, and one end of which is connected to the gas discharge port P2 of the exhaust gas analyzer 2. a second flow path 3L2 connected at one end to the atmosphere introduction port P3 of the exhaust gas analyzer 2, and a sample gas introduction port P1 and a gas discharge port P2 via the flow paths 3L1 to 3L3 and the atmosphere introduction port P3 to change the pressure of the sample gas introduction port P1, the gas discharge port P2 and the atmosphere introduction port P3, and the sample gas introduction port P1 or the gas discharge port P2. and a gas discharge mechanism 32 for discharging gas.

The pressurizing mechanism 31 includes a confluence flow path 311 to which the first to third flow paths 3L1 to 3L3 are connected, and a pressure source that pressurizes the first to third flow paths 3L1 to 3L3 via the confluence flow path 311. 312 and a pressure adjustment unit 313 that adjusts the pressure of the confluence channel 311 .

The confluence flow path 311 has a buffer tank 311a to which the other ends of the first flow path 3L1 and the second flow path 3L2 are connected, and a connection flow path 311b that connects the buffer tank 311a and the pressure source 312. there is The other end of the third flow path 3L3 is connected to the connection flow path 311b.

The pressurization source 312 is a pressurization pump, and the pressurization pump 312 pressurizes the buffer tank 311a via the connection flow path 311b, and the first flow path 3L1 and the second flow path 3L1 connected to the buffer tank 311a. While the channel 3L2 is pressurized, the third channel 3L3 connected to the connection channel 311b is pressurized.

The pressure adjustment unit 313 is connected to the connection channel 311b, and is configured using, for example, a pressure adjustment valve or a needle valve. The pressure adjusting section 313 adjusts the pressure by exhausting part of the air flowing through the connection channel 311b. The pressurizing mechanism 31 also has a pressure sensor (for example, a gauge pressure sensor 314) that detects the pressure in the flow path of the exhaust gas analyzer 2 or the pressure in the buffer tank 311a.

The gas discharge mechanism 32 includes a flow path between the pressure mechanism 31 and the sample gas introduction port P1, a flow path between the pressure mechanism 31 and the gas discharge port P2, and a flow path between the pressure mechanism 31 and the atmosphere introduction port P3. and discharges the gas flowing out from the sample gas introduction port P1 or the gas discharge port P2.

Specifically, the gas discharge mechanism 32 has an exhaust flow path 321 connected to the confluence flow path 311 and a suction pump 322 provided in the exhaust flow path 321 . The exhaust flow path 321 of this embodiment is connected to the buffer tank 311a. Further, the exhaust flow path 321 is provided with a flow rate adjusting section 323 such as a needle valve. The exhaust flow rate by the suction pump 322 is adjusted by the flow rate adjusting section 323 .

Further, the pressure fluctuation device 3 of the present embodiment includes a decompression mechanism 33 for decompressing the sample gas introduction port P1, the gas discharge port P2 and the atmosphere introduction port P3 via the first to third flow paths 3L1 to 3L3, A switching mechanism 34 for switching between a pressurized state by the mechanism 31 and a depressurized state by the depressurizing mechanism 33 is provided.

The decompression mechanism 33 is configured using a part of the configurations of the pressurization mechanism 31 and the gas discharge mechanism 32 described above. Specifically, the decompression mechanism 33 is configured using the suction pump 322 of the gas discharge mechanism 32 . Further, the decompression mechanism 33 is connected to the connection flow path 311b and has an atmosphere introduction path 331 for introducing the atmosphere. A pressure regulating portion 332 such as a pressure regulating valve is provided in the atmosphere introduction passage 331 . The pressure adjustment unit 332 adjusts the pressures of the first flow path L31, the second flow path 3L2, and the third flow path 3L3 to be constant during pressure reduction.

The switching mechanism 34 connects the pressurizing pump 312 to the buffer tank 311a when the pressurizing mechanism 31 operates, and connects the atmosphere introduction passage 331 to the buffer tank 311a when the depressurizing mechanism 33 operates. is. The switching mechanism 34 of the present embodiment is composed of a three-way valve provided at the connection point between the connection channel 311b and the atmosphere introduction channel 331 . The switching mechanism 34 is provided with an opening/closing valve on the pressurizing pump 312 side of the connection point of the atmosphere introduction passage 331 at 311b in the connection flow path, and the opening/closing valve is provided in the atmosphere introduction passage 331. It may be configured by controlling opening and closing.

In addition, in the pressure fluctuation device 3 of the present embodiment, fluid devices including the pressurizing mechanism 31, the gas exhausting mechanism 32, the depressurizing mechanism 33, and the switching mechanism 34 are housed in the housing 35. The connection ports P4 to P6 provided in the housing 35 are connected to connection pipes that form part of the first flow path 3L1, the second flow path 3L2, and the third flow path 3L3. By connecting the housing 35 and the exhaust gas analyzer 2 via the connection pipe in this way, the connection between the exhaust gas analyzer 2 and the pressure fluctuation device 3 can be facilitated.

<Pressure operation>
The switching mechanism 34 connects the pressurizing pump 312 to the buffer tank 311a. In this state, when the suction pump 25 of the exhaust gas analyzer 2 and the pressure pump 312 and suction pump 322 of the pressure fluctuation device 3 are operated to supply the calibration gas from the calibration gas flow path L2, the gas flow is as follows. Become.

That is, the suction pump 25 of the exhaust gas analyzer 2 supplies the calibration gas from the calibration gas flow path L2 to each of the analyzers 21-23. Here, a part of the calibration gas flows out from the sample gas introduction port P1, and the calibration gas that has passed through the analyzers 21 to 23 flows out from the gas discharge port P2. Also, the sample gas introduction port P1 and the gas discharge port P2 are in a state of being pressurized by the pressurizing mechanism 31 (a state in which pressure is applied compared to before the pressurizing mechanism 31 operates). Further, air is introduced into the air introduction port P3 of the exhaust gas analyzer 2 from the third flow path 3L3 via the pressurizing pump 312 . Here, since the calibration gas flowing into the buffer tank 311a is discharged to the outside by the gas discharge mechanism 32, the calibration gas flows backward into the sample gas introduction port P1 and the gas discharge port. It is possible to prevent the liquid from flowing into the third flow path 3L3. As a result, with the sample gas introduction port P1, the gas discharge port P2, and the atmosphere introduction port P3 pressurized (a state in which pressure is applied compared to before the pressurization mechanism 31 operates), each analyzer 21 .about.23 are supplied with calibration gas.

<Decompression operation>
The switching mechanism 34 connects the atmosphere introduction passage 331 to the buffer tank 311a. In this state, when the suction pump 25 of the exhaust gas analyzer 2 and the suction pump 322 of the pressure fluctuation device 3 are operated to supply the calibration gas from the calibration gas flow path L2, the gas flows as follows.

That is, the suction pump 25 of the exhaust gas analyzer 2 supplies the calibration gas from the calibration gas flow path L2 to each of the analyzers 21-23. Here, the calibration gas is sucked from the sample gas introduction port P1 through the first flow path 3L1. Also, air is introduced into the air introduction port P3 of the exhaust gas analyzer 2 from the third flow path 3L3 via the suction pump 322 . Here, since the third flow path 3L3 is connected to the atmosphere introduction path 331, the calibration gas flowing into the buffer tank 311a through the first flow path 3L1 and the second flow path 3L2 flows into the third flow path 3L3. Don't worry about it leaking. As a result, the calibration gas is supplied to each of the analyzers 21 to 23 while the sample gas introduction port P1, the gas discharge port P2 and the air introduction port P3 are decompressed.

<Calibration method (calculation method of pressure correction coefficient)>
Next, a method of calculating the pressure correction coefficient using the pressure fluctuation device 3 configured as described above will be described with reference to FIG. The calibration method of the present embodiment includes reproducing the pressurized state of the exhaust gas analyzer 2, and calculating the pressure correction coefficient of the exhaust gas analyzer 2 in addition to the zero-span calibration of the exhaust gas analyzer 2. . Note that the calibration method may include preparation of a calibration curve.

First, prepare the exhaust gas analyzer 2 to be calibrated. At this time, when the exhaust gas analyzer 2 is mounted on the vehicle, it may be mounted or removed from the vehicle.

Then, the exhaust gas analyzer 2 is warmed up (step S1). At this time, the suction pump 25 of the exhaust gas analyzer 2 is activated. If the exhaust gas analyzer 2 has a pressure correction function, the pressure correction function is turned off.

After the warm-up operation, the zero calibration is performed by flowing the calibration gas for zero calibration to the exhaust gas analyzer 2 under the atmospheric pressure environment. Also, span calibration is performed by flowing a calibration gas for span calibration into the exhaust gas analyzer 2 (step S2). These calibration gases are supplied from the calibration gas flow path L2. At this time, the pressure fluctuation device 3 is in a stopped state.

After that, the channels 3L1 to 3L3 of the pressure fluctuation device 3 are connected to the ports P1 to P3 of the exhaust gas analyzer 2, respectively. In this state, the pressurization mechanism (pressurization pump) and the gas discharge mechanism (suction pump) of the pressure fluctuation device 3 are started (step S3).

Here, the pressure in the buffer tank 311a (the pressure of the gauge pressure sensor 314) is kept constant (for example, at atmospheric pressure conditions of 0 m to 1500 m) by the pressure adjustment unit 313 of the pressurization mechanism 31 or the flow rate adjustment unit 323 of the gas discharge mechanism 32. Adjust (step S4). As for the order of changing the atmospheric pressure conditions, for example, when the exhaust gas analyzer 2 is set at an altitude of 1500 m, the atmospheric pressure conditions are gradually increased to lower altitudes such as 1500 m, 1000 m, 500 m, 0 m, 500 m, 1000 m, and 1500 m. It is conceivable to gradually increase the altitude again after the air pressure condition reaches the predetermined minimum altitude. Here, the measured value of the gauge pressure sensor 314 of the pressure fluctuation device 3 is referred to, and the pressure adjusting section 313 or the flow rate adjusting section 323 is operated to control the desired pressure. This operation may be automatically controlled using a computer, or may be manually performed by an operator.

Under each pressure condition, the calibration gas for zero calibration and the calibration gas for span calibration are respectively flowed, and measurements are performed by each analyzer 21 to 23 (step S5). These calibration gases flow into the main flow path L1 from the calibration gas flow path L2. At this time, an excess amount of the calibration gas is supplied so that it flows not only to the downstream side (gas discharge port P2) from the connection point but also to the upstream side (sample gas introduction port P1). That is, the calibration gas flows out from the sample gas introduction port P1 to the first flow path 3L1. This allows pure calibration gas to flow into each analyzer 21-23. This is because if the calibration gas does not flow backward from the sample gas introduction port P1, the atmosphere will be introduced from the sample gas introduction port P1, which will dilute the calibration gas and prevent accurate calibration. The excess amount means that the supply flow rate of the calibration gas is larger than the flow rate obtained by subtracting the introduction amount from the atmosphere introduction port P3 from the discharge amount from the gas discharge port P2.

After each measurement is completed (step S6), the pressure fluctuation device 3 and the exhaust gas analyzer 2 are stopped (step S7). Then, a pressure correction coefficient (step S8) is calculated from the measurement results obtained by each measurement. Specifically, a pressure correction coefficient is created so that the measurement result obtained from each measurement matches the measurement value of the calibration gas at the reference pressure.

By varying the pressure to a plurality of pressures and acquiring the measurement values of each analyzer 21-23 at each pressure, the pressure correction coefficient of each analyzer 21-23 can be obtained.
Here, this pressure correction coefficient may be configured to be calculated by the information processing section 4, or may be manually calculated by the operator. Note that the pressure correction coefficient may be in a tabular format or in a functional format. Data of the pressure correction coefficient obtained in this manner is stored in the internal memory of the information processing section 4 .

By performing the above process for each calibration gas with different concentrations, the pressure correction coefficient at each concentration can be obtained. When using a plurality of calibration gases of different gas types, the same operation may be performed for each calibration gas, or a mixed gas of a plurality of calibration gases may be used for calibration.

By using this pressure correction coefficient, the information processing unit 4 calculates the reference pressure ( The pressure at the time of preparing the calibration curve is corrected to calculate the concentration converted to the pressure at the time of preparation of the calibration curve.

In the above, the procedure for obtaining the pressure correction coefficient with the flue gas analyzer in a pressurized state was shown. , the pressure correction coefficient can be obtained by reproducing not only the state of altitude lower than the calibration point, but also the state of altitude higher than the calibration point.

<Effects of this embodiment>
According to the gas analysis system 100 of the present embodiment, since the pressure fluctuation device 3 is connected to the sample gas introduction port P1 and the gas discharge port P2 of the exhaust gas analyzer 2, the exhaust gas can be analyzed without using a pressurization test chamber. The state of pressurization for the device 2 can be reproduced. Therefore, at altitudes lower than the calibration point, the pressure correction coefficient can be obtained with high accuracy without extrapolative correction of the pressure correction coefficient. As a result, the measurement result of the exhaust gas analyzer 2 can be accurately measured without extrapolation.

In particular, in this embodiment, the calibration gas flowing out of the sample gas introduction port P1 or the gas discharge port P2 is applied to the pressure fluctuation device 3 while the sample gas introduction port P1, the gas discharge port P2, and the atmosphere introduction port P3 are pressurized. Since the calibration gas is discharged by the gas discharge mechanism 32, the backflow of the calibration gas due to pressurization is suppressed, and the pressure correction coefficient can be obtained with high accuracy.

<Modified embodiment>
It should be noted that the present invention is not limited to the above embodiments.

For example, the exhaust gas analyzer 2 has the function of diluting the exhaust gas and the ozone generator, so it has the atmosphere introduction passage L3. It may be something that does not have.

In addition, the air does not necessarily need to be introduced into the air introduction port P3 and the air introduction path 3L3. For example, oxygen or ozone may be supplied from a cylinder, or other gas may be supplied.

Furthermore, as shown in FIG. 5, the pressure fluctuation device 3 may be configured to have only the function of pressurizing the gas analysis device 2 without having the decompression mechanism 33 and the switching mechanism 34 .

As a modification of the pressure adjusting unit 313 of the pressurizing mechanism 31 of the above-described embodiment, as shown in FIG. The desired pressure may be obtained by adjusting the pressure. Here, the on-off valve 315 is on/off-controlled so that the pressure detected by the gauge pressure sensor 314, for example, becomes the target pressure.

As the pressurization source 312, in addition to the pressurization pump, as shown in FIG. 7, a pressurization container 316 such as a buffer tank storing gas pressurized above the ambient pressure may be used. Also, a compressor 317 may be connected to the pressurized container 316 . 7 has the same configuration as that of the above-described embodiment, it may have a configuration using the on-off valve 315 shown in FIG.

In the above embodiment, the data of the pressure correction coefficients are stored in the internal memory of the exhaust gas analyzer 2, but the data of the pressure correction coefficients are stored in the internal memory of the information processing device which is separate from the exhaust gas analyzer 2. Alternatively, the information processing device may acquire analysis data from the analyzers 21 to 23 of the exhaust gas analyzer 2 and correct the pressure.

Furthermore, the pressure fluctuation device of the above embodiment may be configured to automatically switch between the pressurized state and the depressurized state. Specifically, the pressure variation device may further include a control unit that controls the switching mechanism to automatically switch between the pressurized state and the depressurized state. In this case, the control unit may compare the pressure of the gauge pressure sensor 314 and a preset target pressure, for example, and automatically switch between the pressurized state and the depressurized state.

Further, as shown in FIG. 8, the pressure correction coefficient of the gas analyzer 2 can be calculated by cooperatively controlling the gas analyzer 2 and the pressure fluctuation device 3 using an external operating device 6 such as a computer. . Specifically, the operation of the gas analyzer 2 is performed using an external operation device 6 . The external operation device 6 performs operations for starting and stopping measurement of the gas analyzer 2 via a communication cable or the like. A control unit 51 (which may be the information processing unit 4 ) of the gas analyzer 2 controls the suction pump 25 and various valves according to signals from the external operation device 6 . Moreover, the operation of the pressure fluctuation device 3 is performed using an external operation device 6 . The external operation device 6 performs operations for starting and stopping the pressure variation device 3 via a communication cable or the like. The control unit 52 of the pressure fluctuation device 3 controls the pressure pump 313, the suction pump 322, various valves 323, etc. according to the signal from the external operation device 6. FIG. The external operating device 6 has a judgment section 61 for judging whether the pressure inside the gas analyzer 2 and the pressure fluctuation device 3 is positive pressure or negative pressure with respect to a preset target pressure. As the pressure gauge referred to by the determination unit 61, for example, the gauge pressure sensor 314 is used. Then, based on the determination result of the determination unit 61, the external operation device 6 outputs control command signals for the pumps and the like of each device to the gas analysis device 2 and the pressure fluctuation device 3 so as to achieve a preset target pressure. do. Note that the function of the determination unit 61 may be provided in the control unit 51 or the control unit 52 .

In the calibration method of the above embodiment, zero/span calibration (step S2) is performed, but zero/span calibration may not be performed.

Furthermore, the pressure correction coefficient may be created using the pressure at the time of zero/span calibration in addition to the pressure at the time of calibration curve creation as the reference pressure.

Also, a pressure variation device different from the above embodiment may be connected to any of the sample gas introduction port, gas discharge port, and atmosphere introduction port of the gas analyzer. Then, by controlling these pressure variation devices, each port may be adjusted to the same pressure.

Also, the sample gas introduction port, the gas discharge port, and the air introduction port of the gas analyzer may be independently provided with a pressurization mechanism and a gas discharge mechanism. In addition, gas exhaust mechanisms may be provided between the pressurizing mechanism and the sample gas introduction port, between the pressurizing mechanism 31 and the gas exhaust port, and between the pressurizing mechanism and the atmosphere introducing port.

The technical idea of the pressure fluctuation device of the embodiment can also be said as follows.
In other words, the pressure fluctuation device is a pressure fluctuation device that fluctuates the pressure of the gas analysis device, and the first channel connected to the sample gas introduction port of the gas analysis device and the gas discharge port of the gas analysis device. a connected second flow path, a gas discharge mechanism for discharging gas from the sample gas introduction port and the gas discharge port via the first flow path and the second flow path, and the gas discharge mechanism Pressure is applied to the flow path between the sample gas introduction port and the flow path between the gas discharge mechanism and the gas discharge port to vary the pressures of the sample gas introduction port and the gas discharge port. and a pressurizing mechanism. Even with this configuration, a gas analysis system similar to that of the above embodiment can be configured.

Also, in the above embodiment, a vehicle-mounted type exhaust gas analyzer has been described, but a stationary type exhaust gas analyzer may be used instead of a vehicle-mounted type. Further, the measurement target of the exhaust gas analyzer is not limited to exhaust gas from vehicles, but may be exhaust gas from other moving bodies such as engines or ships, or the atmosphere may be directly measured.

In the above embodiments, an exhaust gas analyzer that analyzes exhaust gas from a vehicle equipped with a gasoline engine or a diesel engine has been described. can also be applied. By using an analyzer equipped with a fisherman's cascade laser (QCL) in the analysis part, leaked hydrogen from the fuel cell was measured in the exhaust gas of the fuel cell, and the exhaust gas of the hydrogen engine did not react in the combustion tower. Unburned hydrogen may be measured.

In addition, various modifications and combinations of the embodiments may be made as long as they do not contradict the spirit of the present invention.

According to the present invention, it is possible to obtain the pressure correction coefficient with high accuracy while reproducing the state of pressurization for the gas analyzer.

100 Gas analysis system 2 Exhaust gas analyzer (gas analyzer)
P0...Calibration gas introduction port P1...Sample gas introduction port P2...Gas discharge port P3...Atmosphere introduction port 3...Pressure fluctuation device 31...Pressurization mechanism 32...Gas discharge Mechanism 322 Suction pump 311 Merging channel 312 Pressurization source (pressurization pump)
313... Pressure adjustment part 311a... Buffer tank 33... Decompression mechanism 34... Switching mechanism

Claims (16)

1. connecting a pressure fluctuation device having a pressurization mechanism and a gas discharge mechanism to the sample gas introduction port and the gas discharge port of the gas analyzer;
   applying pressure to the sample gas introduction port and the gas discharge port by the pressurizing mechanism of the pressure fluctuation device to vary the pressures of the sample gas introduction port and the gas discharge port;
   While the calibration gas is being introduced from the calibration gas introduction port of the gas analyzer in a state where the pressure is fluctuated, the calibration gas flowing out from the sample gas introduction port or the gas discharge port is discharged from the pressure fluctuation device. discharged by the mechanism,
   A method of calibrating a gas analyzer, comprising calculating a pressure correction coefficient of the gas analyzer using a measurement result of the calibration gas in the gas analyzer.
2. A plurality of pressures are varied by the pressure variation device, and the pressure correction coefficient of the gas analyzer is calculated so that the measurement results of the calibration gas at each of the plurality of pressures match the measurement results of the calibration gas at the reference pressure. The method for calibrating a gas analyzer according to claim 1, wherein
3. 3. The method of calibrating a gas analyzer according to claim 1 or 2, wherein an excessive amount of calibration gas is introduced from the calibration gas introduction port, and the calibration gas is measured while overflowing the calibration gas from the sample gas introduction port.
4. The gas analyzer further comprises an atmosphere introduction port,
   The pressure variation device is connected to the atmosphere introduction port to apply pressure to the sample gas introduction port, the gas discharge port and the atmosphere introduction port to apply pressure to the sample gas introduction port, the gas discharge port and the atmosphere introduction port. 4. The method for calibrating a gas analyzer according to any one of claims 1 to 3, wherein the pressure of is varied.
5. The gas analyzer calibration method according to any one of claims 1 to 4, wherein the gas analyzer is of a vehicle-mounted type.
6. Using the pressure correction coefficient obtained by the calibration method according to any one of claims 1 to 5, the measurement result of the actual measurement of the gas analysis device is converted to the gas analysis method based on the pressure at the time of the actual measurement. A pressure correction method for a gas analyzer for correcting measurement results at the reference pressure of the device.
7. A pressure fluctuation device having a pressurization mechanism and a gas discharge mechanism is connected to a sample gas introduction port and a gas discharge port of a gas analyzer having a pressure correction function using a pressure correction coefficient,
   applying pressure to the sample gas introduction port and the gas discharge port by the pressurizing mechanism of the pressure fluctuation device to vary the pressures of the sample gas introduction port and the gas discharge port;
   While the calibration gas is being introduced from the calibration gas introduction port of the gas analyzer in a state where the pressure is fluctuated, the calibration gas flowing out from the sample gas introduction port or the gas discharge port is discharged from the pressure fluctuation device. discharged by the mechanism,
   A method of inspecting a gas analyzer, comprising comparing a measured value after correction using the pressure correction factor in the gas analyzer with a known concentration of the calibration gas at a reference pressure.
8. connecting a pressure fluctuation device having a pressurization mechanism and a gas discharge mechanism to the sample gas introduction port and the gas discharge port of the gas analyzer;
   The pressurizing mechanism of the pressure variation device applies pressure to the sample gas introduction port and the gas discharge port to vary the pressure of the sample gas introduction port and the gas discharge port, thereby increasing the pressure of the gas analyzer. A pressure fluctuation method, wherein the gas flowing out from the sample gas introduction port or the gas discharge port is discharged by the gas discharge mechanism of the pressure fluctuation device while being varied.
9. A pressure fluctuation device for fluctuating the pressure of a gas analyzer,
   a first channel connected to the sample gas introduction port of the gas analyzer;
   a second flow path connected to a gas discharge port of the gas analyzer;
   a pressure mechanism that applies pressure to the sample gas introduction port and the gas discharge port via the first flow path and the second flow path to vary the pressures of the sample gas introduction port and the gas discharge port;
   It is connected to a flow path between the pressurization mechanism and the sample gas introduction port and a flow path between the pressurization mechanism and the gas discharge port, and flows out from the sample gas introduction port or the gas discharge port. and a gas discharge mechanism for discharging gas.
10. The pressure mechanism is
    a confluence channel where the first channel and the second channel are connected;
    a pressurization source that pressurizes the first channel and the second channel through the merged channel;
    10. The pressure fluctuation device according to claim 9, further comprising a pressure adjustment section that adjusts the pressure of said confluence flow path.
11. The confluence channel has a buffer tank,
    The pressurization source is a pump,
    11. The pressure fluctuation device according to claim 10, wherein said first channel and said second channel are connected to said pump via a buffer tank.
12. a decompression mechanism for decompressing the sample gas introduction port and the gas discharge port through the first flow path and the second flow path;
    12. The pressure fluctuation device according to any one of claims 9 to 11, further comprising a switching mechanism for switching between a pressurized state by said pressurizing mechanism and a depressurized state by said depressurizing mechanism.
13. The pressure fluctuation device according to claim 12, further comprising a control unit that controls the switching mechanism to automatically switch between the pressurized state and the depressurized state.
14. The gas discharge mechanism has a suction pump,
    14. The pressure fluctuation device according to claim 12, wherein said decompression mechanism is constructed using said suction pump.
15. further comprising a third flow path connected to the atmosphere introduction port of the gas analyzer,
    15. The pressurizing mechanism according to any one of claims 9 to 14, wherein the pressurizing mechanism applies pressure to the atmosphere introduction port via the third flow path to vary the pressure of the atmosphere introduction port. Pressure fluctuation device.
16. a gas analyzer for analyzing a component to be measured in a sample gas;
    A gas analysis system comprising the pressure fluctuation device according to any one of claims 9 to 15.

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