WO2024142622A1 - Gas measurement system and gas measurement method - Google Patents

Gas measurement system and gas measurement method Download PDF

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WO2024142622A1
WO2024142622A1 PCT/JP2023/040601 JP2023040601W WO2024142622A1 WO 2024142622 A1 WO2024142622 A1 WO 2024142622A1 JP 2023040601 W JP2023040601 W JP 2023040601W WO 2024142622 A1 WO2024142622 A1 WO 2024142622A1
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oxygen concentration
gas
oxygen
reference gas
concentration sensor
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PCT/JP2023/040601
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French (fr)
Japanese (ja)
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卓司 生田
健太郎 石田
佳洋 横田
雅彦 藤原
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株式会社堀場製作所
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  • the present invention relates to a gas measurement system and a gas measurement method.
  • Magnetic pressure oxygen meters are excellent in stability and accuracy, and in this respect are suitable for use in fuel efficiency measurement using the above fuel efficiency measurement method.
  • the principle of magnetic pressure oxygen meters is to measure oxygen concentration using the magnetism of oxygen, and they measure oxygen concentration from the pressure difference proportional to the difference in magnetic susceptibility between a sample gas and a reference gas (auxiliary gas) that come into contact within a magnetic field.
  • the pressure difference will be near zero, and the output signal from the magnetic oxygen meter will be near zero.
  • a signal output from the magnetic oxygen meter near zero is hardly affected by disturbances (for example, even if an output of zero is multiplied by a disturbance factor, the output will remain zero).
  • possible disturbances include pressure changes in the sample gas, changes in flow rate, and changes in ambient temperature.
  • the pressure difference i.e. the difference in oxygen concentration between the sample gas and the reference gas
  • the output signal from the magnetic oxygen meter will be more likely to fluctuate due to disturbances.
  • one oxygen analyzer measures the oxygen concentration in each bag, and one cylinder is used to store the reference gas.
  • a pressure difference occurs between the diluted sample gas and the reference gas due to the decrease in oxygen concentration that accompanies oxygen consumption in the fuel cell.
  • the output signal from the oxygen analyzer that measures the oxygen concentration of the diluted sample gas is easily affected by external disturbances.
  • the present invention has been made to solve the above problems, and its purpose is to provide a gas measurement system and a gas measurement method that can reduce the effect of external disturbances on the output of a sensor that measures the oxygen concentration in exhaust gas (emitted from a test specimen such as a fuel cell).
  • a gas measurement system includes a first oxygen concentration sensor that measures the concentration of oxygen in the exhaust gas discharged from a test specimen as a first oxygen concentration based on the pressure difference between the oxygen in the exhaust gas and a first reference gas having an oxygen concentration of a first predetermined concentration, a first reference gas supply unit that supplies the first reference gas to the first oxygen concentration sensor, and a calculation unit that calculates the oxygen consumption of the test specimen based on the flow rate of the exhaust gas and the first oxygen concentration, and the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration.
  • the present invention it is possible to make the output of the first oxygen concentration sensor that measures the oxygen concentration (first oxygen concentration) in exhaust gas less susceptible to disturbances.
  • FIG. 1 is an explanatory diagram showing a schematic configuration of a gas measurement system according to an embodiment of the present invention
  • FIG. 2 is a block diagram showing a main part of the gas measurement system.
  • FIG. 4 is an explanatory diagram showing main parts of another configuration of the gas measurement system.
  • FIG. 4 is an explanatory diagram showing still another configuration of the gas measurement system.
  • the measurement gas flow rate control unit 233 includes a second pump P2, a first flow meter FM1, a measurement gas on-off valve V23 , and an operation control unit (not shown) for controlling the operations of these components.
  • the second pump P2 and the first flow meter FM1 are disposed in a flow path between the dilution tunnel 21 and the measurement gas sampling bag 231.
  • the measurement gas on-off valve V23 is provided on the inlet side and the outlet side of each measurement gas sampling bag 231.
  • the first flow meter FM1 may be a critical flow venturi.
  • the dilution gas flow rate control unit 243 includes a third pump P3, a second flow meter FM2, a dilution gas on-off valve V24 , and an operation control unit (not shown) for controlling the operations of these components.
  • the third pump P3 and the second flow meter FM2 are disposed in a flow path between the dilution gas supply path 22 and the dilution gas sampling bag 241.
  • the dilution gas on-off valve V24 is provided on the inlet side and the outlet side of each dilution gas sampling bag 241.
  • the second flow meter FM2 may be a critical flow venturi.
  • the gas measurement system 1 further includes a first oxygen concentration sensor 3, a first reference gas supply unit 4, a second oxygen concentration sensor 5, and a second reference gas supply unit 6.
  • the first oxygen concentration sensor 3 is composed of a magnetic pressure oxygen meter with excellent stability and accuracy. As described above, the magnetic pressure oxygen meter measures the oxygen concentration from the pressure difference proportional to the difference in magnetic susceptibility between the measurement gas and the reference gas. Therefore, the first oxygen concentration sensor 3 measures the concentration of oxygen in the exhaust gas based on the pressure difference between the oxygen in the exhaust gas discharged from the vehicle 100 and the first reference gas (supplied from the first reference gas supply unit 4). In particular, the first oxygen concentration sensor 3 measures the oxygen concentration in the exhaust gas contained in the measurement gas sampling bag 231 (first bag).
  • the oxygen concentration measured by the first oxygen concentration sensor 3 is also referred to as the first oxygen concentration to distinguish it from the oxygen concentration measured by the second oxygen concentration sensor 5.
  • the first oxygen concentration sensor 3 measures the oxygen concentration in the exhaust gas contained in the measurement gas sampling bag 231, and the average value of the oxygen concentration in the measurement gas sampling bag 231 can be obtained as the first oxygen concentration.
  • the second oxygen concentration sensor 5 measures the oxygen concentration in the air contained in the diluted gas sampling bag 241, and the average oxygen concentration value within the diluted gas sampling bag 241 can be obtained as the second oxygen concentration.
  • the dilution ratio D is calculated as follows.
  • the flow rate of exhaust gas discharged from the vehicle 100 and heading toward the dilution tunnel 21 is Q2 ( m3 /min).
  • the flow rate of the diluted gas (air) supplied to the diluted gas supply passage 22 is Q3 ( m3 /min).
  • the flow rate Q2 of the exhaust gas varies depending on the accelerator opening of the vehicle 100 (the vehicle speed of the vehicle 100 measured on the dynamometer DY).
  • the dilution ratio D is expressed by the following formula:
  • the dilution ratio D is calculated by the calculation unit 7, for example, every 0.1 seconds. Therefore, when calculating the amount of hydrogen consumed ⁇ VH2 in a predetermined time, the average value of the dilution ratio D in the above-mentioned predetermined time can be used.
  • the concentration of oxygen in the exhaust gas discharged from the vehicle 100 (first oxygen concentration) is lower than the concentration of oxygen in the air (diluted gas) supplied to the vehicle 100 (second oxygen concentration).
  • first oxygen concentration the concentration of oxygen in the exhaust gas discharged from the vehicle 100
  • second oxygen concentration the concentration of oxygen in the air supplied to the vehicle 100
  • the specimen is either a fuel cell 101, a vehicle 100 equipped with a fuel cell 101, or a part of a vehicle 100 equipped with a fuel cell 101.
  • the hydrogen consumption of the fuel cell 101, etc. can be calculated.
  • the calculation unit 7 can measure fuel efficiency by using hydrogen consumption and mileage information of the test specimen.
  • mileage information is obtained by mounting the vehicle 100 on a dynamometer DY (see FIG. 1) and simulating driving conditions similar to road driving. If the test specimen is in a form that cannot run, the fuel efficiency may be measured by converting the work amount information of the test specimen into mileage information.
  • the work amount information refers to information on the amount of work done by the test specimen per unit time. For example, if it is known in advance that the test specimen will run N (km) with a work amount of K (W) per unit time, the fuel efficiency of the test specimen can be measured by calculating hydrogen consumption/N/K, that is, the amount of gas consumed per unit work amount of the test specimen can be measured.
  • the calculation unit 7 may also acquire work volume information of the test specimen, and use the work volume information to calculate the work volume per unit of hydrogen consumption. Furthermore, the calculation unit 7 may acquire mileage information of the test specimen from the dynamometer DY, and calculate the mileage per unit of hydrogen consumption based on the acquired mileage information. By determining the work volume per unit of hydrogen consumption or the mileage per unit of hydrogen consumption, the fuel consumption of the test specimen can be analyzed and evaluated.
  • the first predetermined concentration of the first reference gas is set based on a predicted value of the amount of decrease in oxygen concentration due to oxygen consumption in the vehicle 100 (fuel cell 101) as a test specimen. For example, if oxygen is contained in the atmosphere at a concentration of 21 vol%, and the predicted value of the amount of decrease in oxygen concentration due to oxygen consumption by power generation in the fuel cell 101 is 16 vol%, the first predetermined concentration of the first reference gas is set to, for example, 21-16 ⁇ (1/D) using the dilution ratio D.
  • the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration (for example, 19.4 vol%) expected to be output by the first oxygen concentration sensor 3. It is considered that the above-mentioned first predetermined range is desirably within a range of at least 1 vol.% from the above-mentioned first oxygen concentration predicted to be output by the first oxygen concentration sensor 3, is further desirably within a range of 0.5 vol.%, and is even more desirably within a range of 0.2 vol.%.
  • the predicted value of the decrease in the oxygen concentration can be obtained, for example, by referring to the performance specifications of the fuel cell 101 or the vehicle 100 equipped with the fuel cell 101, performance simulation data, oxygen consumption data obtained in advance from preliminary tests, etc.
  • the first oxygen concentration sensor 3 measures the oxygen concentration in the exhaust gas (first oxygen concentration) based on the pressure difference between the oxygen in the exhaust gas and the first reference gas
  • first predetermined concentration the smaller the difference between the first oxygen concentration and the oxygen concentration of the first reference gas (first predetermined concentration)
  • the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration, so that the difference between the first oxygen concentration and the first predetermined concentration can be reduced and the pressure difference can be made closer to zero.
  • the first predetermined concentration can be appropriately set based on the predicted amount of decrease.
  • the first predetermined concentration of the first reference gas be within a first predetermined range of the first oxygen concentration in the exhaust gas averaged in the measurement gas sampling bag 231.
  • the second predetermined concentration of the second reference gas is set within a second predetermined range (for example, within 1 vol%) from the concentration of oxygen contained in the dilution gas, that is, the second oxygen concentration measured by the second oxygen concentration sensor 5.
  • a second predetermined range for example, within 1 vol% from the concentration of oxygen contained in the dilution gas, that is, the second oxygen concentration measured by the second oxygen concentration sensor 5.
  • the second predetermined concentration may be set to, for example, 20.5 vol% as long as it is within the second predetermined range.
  • the second predetermined range is preferably within at least 1 vol% from the second oxygen concentration (for example, 21 vol%) expected to be output by the second oxygen concentration sensor 5, more preferably within 0.5 vol%, and even more preferably within 0.2 vol%.
  • the first or second predetermined concentration can be set based on previous measurement results measured under the same measurement conditions.
  • the “same measurement conditions” may be the same as the measurement conditions when the specimen is the same or another specimen of the same model, or may be the same as the measurement conditions obtained with another gas measurement system having the same or similar performance as the gas measurement system 1 of this embodiment.
  • the "previous measurement results” are past measurement results, and are measurement results previously performed with another specimen and/or gas measurement system 1 of the same model or another individual.
  • the past may be a time point prior to the measurement, even if it is the same day as the actual measurement. Therefore, even if it is the same day as the actual measurement, a measurement result obtained by performing a preliminary test prior to the measurement is also included in the past measurement results.
  • the past measurement results can be used as the first or second predetermined concentration.
  • An example of a past measurement result is the average concentration value in the sampling bag.
  • the gas measurement method in the gas measurement system 1 of this embodiment can be expressed as follows. That is, the method includes a first reference gas supply step in which the first reference gas supply unit 4 supplies a first reference gas having an oxygen concentration of a first predetermined concentration to the first oxygen concentration sensor 3, a first oxygen concentration measurement step in which the first oxygen concentration sensor 3 measures the concentration of oxygen in the exhaust gas discharged from the test specimen as a first oxygen concentration based on the pressure difference between the oxygen in the exhaust gas and the first reference gas, and a calculation step in which the calculation unit 7 calculates the oxygen consumption of the test specimen based on the exhaust gas flow rate and the first oxygen concentration.
  • the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration.
  • the first reference gas supply unit 4 supplies the first reference gas having an oxygen concentration of approximately 19.4 vol% to the first oxygen concentration sensor 3 not only as the first reference gas but also as a gas for zero calibration via the first reference gas supply path 42.
  • the first reference gas supply unit 4 also supplies the first reference gas having an oxygen concentration of approximately 19.4 vol% to the second oxygen concentration sensor 5 as a gas for span calibration via the first span calibration gas supply path 43.

Abstract

A gas measurement system comprising a first oxygen concentration sensor which measures, as a first oxygen concentration, the concentration of oxygen in an exhaust gas exhausted from a test specimen on the basis of a pressure difference between the oxygen in the exhaust gas and a first reference gas in which the concentration of oxygen is a first predetermined concentration, a first reference gas supply unit which supplies the first reference gas to the first oxygen concentration sensor, and a calculation unit which calculates an oxygen consumption amount of the test specimen on the basis of a flow amount of the exhaust gas and the first oxygen concentration. The first predetermined concentration of the first reference gas is set within a first predetermined range with respect to the first oxygen concentration.

Description

ガス測定システムおよびガス測定方法Gas measurement system and gas measurement method
　本発明は、ガス測定システムおよびガス測定方法に関する。 The present invention relates to a gas measurement system and a gas measurement method.
　近年、エンジンなどの内燃機関に代わり、燃料電池を搭載した車両（ＦＣＶ；Fuel　Cell　Vehicle　）の開発が進んでいる。ＦＣＶの燃費計測手法として、ＣＶＳ（Constant　Volume　Sampler　）を用いた酸素バランス法が現在研究されている（例えば非特許文献１参照）。この燃費計測手法では、燃料電池での反応前の、バッグに貯めた希釈空気の酸素濃度と、燃料電池での反応後の、バッグに貯めた希釈サンプルガスの酸素濃度とをそれぞれ酸素分析計で測定し、得られた酸素濃度の差に応じて決まる酸素消費量を、燃料電池での水素消費量に換算する。サンプルガスの希釈により、酸素濃度の差は小さい値となるため、用いる酸素分析計としては、高精度の分析計が要求される。磁気圧式酸素計は、安定性および精度に優れており、この点で、上記燃費計測手法による燃費計測に好適に用いられる。 In recent years, development of vehicles equipped with fuel cells (FCVs; Fuel Cell Vehicles) has progressed in place of internal combustion engines such as internal combustion engines. As a method for measuring fuel efficiency of FCVs, an oxygen balance method using a CVS (Constant Volume Sampler) is currently being researched (see, for example, Non-Patent Document 1). In this fuel efficiency measurement method, the oxygen concentration of the diluted air stored in a bag before the reaction in the fuel cell and the oxygen concentration of the diluted sample gas stored in a bag after the reaction in the fuel cell are measured with an oxygen analyzer, and the oxygen consumption amount determined according to the difference in the obtained oxygen concentrations is converted into the hydrogen consumption amount in the fuel cell. Since the difference in oxygen concentration becomes a small value due to the dilution of the sample gas, a high-precision analyzer is required for the oxygen analyzer used. Magnetic pressure oxygen meters are excellent in stability and accuracy, and in this respect are suitable for use in fuel efficiency measurement using the above fuel efficiency measurement method.
　磁気圧式酸素計は、酸素の磁性を利用して酸素の濃度を測定する原理上、磁界内で接触したサンプルガスとリファレンスガス（補助ガス）との間の磁化率の差に比例した圧力差から酸素濃度を測定する。 The principle of magnetic pressure oxygen meters is to measure oxygen concentration using the magnetism of oxygen, and they measure oxygen concentration from the pressure difference proportional to the difference in magnetic susceptibility between a sample gas and a reference gas (auxiliary gas) that come into contact within a magnetic field.
　ここで、例えば、サンプルガスの酸素濃度がリファレンスガスの酸素濃度と同等であれば、上記圧力差はゼロ付近となり、磁気圧式酸素計からの出力信号はゼロ付近となる。磁気圧式酸素計からの出力がゼロ付近の信号は、外乱の影響をほとんど受けない（例えば出力ゼロに対して外乱因子を乗じても、出力はゼロのままである）。なお、上記の外乱としては、サンプルガスの圧力変化、流量変化、周囲温度の変化等が考えられる。逆に、上記圧力差（つまりサンプルガスとリファレンスガスの酸素濃度の差）が大きいと、磁気圧式酸素計からの出力信号は、外乱の影響を受けて変動しやすくなる。 Here, for example, if the oxygen concentration of the sample gas is equivalent to that of the reference gas, the pressure difference will be near zero, and the output signal from the magnetic oxygen meter will be near zero. A signal output from the magnetic oxygen meter near zero is hardly affected by disturbances (for example, even if an output of zero is multiplied by a disturbance factor, the output will remain zero). Note that possible disturbances include pressure changes in the sample gas, changes in flow rate, and changes in ambient temperature. Conversely, if the pressure difference (i.e. the difference in oxygen concentration between the sample gas and the reference gas) is large, the output signal from the magnetic oxygen meter will be more likely to fluctuate due to disturbances.
　非特許文献１に記載のシステムでは、１つの酸素分析計で、それぞれのバック中の酸素濃度を測定しており、使用するリファレンスガスを収容するボンベも１つである。磁気圧式酸素計による希釈サンプルガスの酸素濃度の測定では、希釈サンプルガスとリファレンスガスとの間に、燃料電池での酸素の消費に伴う酸素濃度の低下分の圧力差が生じる。このため、非特許文献１のシステムでは、希釈サンプルガスの酸素濃度を測定する酸素分析計からの出力信号が外乱の影響を受けやすくなる。 In the system described in Non-Patent Document 1, one oxygen analyzer measures the oxygen concentration in each bag, and one cylinder is used to store the reference gas. When measuring the oxygen concentration of the diluted sample gas using a magnetic pressure oxygen meter, a pressure difference occurs between the diluted sample gas and the reference gas due to the decrease in oxygen concentration that accompanies oxygen consumption in the fuel cell. For this reason, in the system described in Non-Patent Document 1, the output signal from the oxygen analyzer that measures the oxygen concentration of the diluted sample gas is easily affected by external disturbances.
　本発明は、上記の問題点を解決するためになされたものであり、その目的は、（燃料電池などの供試体から排出される）排ガス中の酸素濃度を測定するセンサの出力に対して外乱の影響を受けにくくすることができるガス測定システムおよびガス測定方法を提供することにある。 The present invention has been made to solve the above problems, and its purpose is to provide a gas measurement system and a gas measurement method that can reduce the effect of external disturbances on the output of a sensor that measures the oxygen concentration in exhaust gas (emitted from a test specimen such as a fuel cell).
　本発明の一側面に係るガス測定システム、供試体から排出される排ガス中の酸素と、酸素濃度が第１所定濃度である第１リファレンスガスとの圧力差に基づいて、前記排ガス中の前記酸素の濃度を第１酸素濃度として測定する第１酸素濃度センサと、前記第１リファレンスガスを前記第１酸素濃度センサに供給する第１リファレンスガス供給部と、前記排ガスの流量と前記第１酸素濃度とに基づいて、前記供試体の酸素消費量を算出する演算部と、を備え、前記第１リファレンスガスの前記第１所定濃度は、前記第１酸素濃度から第１所定範囲内に設定される。 A gas measurement system according to one aspect of the present invention includes a first oxygen concentration sensor that measures the concentration of oxygen in the exhaust gas discharged from a test specimen as a first oxygen concentration based on the pressure difference between the oxygen in the exhaust gas and a first reference gas having an oxygen concentration of a first predetermined concentration, a first reference gas supply unit that supplies the first reference gas to the first oxygen concentration sensor, and a calculation unit that calculates the oxygen consumption of the test specimen based on the flow rate of the exhaust gas and the first oxygen concentration, and the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration.
　本発明の他の側面に係るガス測定方法は、酸素濃度が第１所定濃度である第１リファレンスガスを第１酸素濃度センサに供給する第１リファレンスガス供給工程と、供試体から排出される排ガス中の酸素と、前記第１リファレンスガスとの圧力差に基づいて、前記排ガス中の前記酸素の濃度を第１酸素濃度として測定する第１酸素濃度測定工程と、前記排ガスの流量と前記第１酸素濃度とに基づいて、前記供試体の酸素消費量を算出する演算工程と、を備え、前記第１リファレンスガスの前記第１所定濃度は、前記第１酸素濃度から第１所定範囲内に設定される。 A gas measurement method according to another aspect of the present invention includes a first reference gas supplying step of supplying a first reference gas having an oxygen concentration of a first predetermined concentration to a first oxygen concentration sensor, a first oxygen concentration measuring step of measuring the concentration of oxygen in the exhaust gas discharged from a test specimen as a first oxygen concentration based on the pressure difference between the oxygen in the exhaust gas and the first reference gas, and a calculation step of calculating the oxygen consumption of the test specimen based on the flow rate of the exhaust gas and the first oxygen concentration, and the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration.
　本発明によれば、排ガス中の酸素濃度（第１酸素濃度）を測定する第１酸素濃度センサの出力に対して外乱の影響を受けにくくすることができる。 According to the present invention, it is possible to make the output of the first oxygen concentration sensor that measures the oxygen concentration (first oxygen concentration) in exhaust gas less susceptible to disturbances.
本発明の実施の一形態に係るガス測定システムの概略の構成を示す説明図である。1 is an explanatory diagram showing a schematic configuration of a gas measurement system according to an embodiment of the present invention; 上記ガス測定システムの主要部を示すブロック図である。FIG. 2 is a block diagram showing a main part of the gas measurement system. 上記ガス測定システムの他の構成の主要部を示す説明図である。FIG. 4 is an explanatory diagram showing main parts of another configuration of the gas measurement system. 上記ガス測定システムのさらに他の構成を示す説明図である。FIG. 4 is an explanatory diagram showing still another configuration of the gas measurement system.
　以下、本発明の例示的な実施形態について、図面を参照しながら説明する。 Below, an exemplary embodiment of the present invention will be described with reference to the drawings.
　〔１．ガス測定システムの概要〕
　図１は、本実施形態のガス測定システム１の概略の構成を示す説明図である。ガス測定システム１は、供試体の酸素消費量を測定するシステムである。ガス測定システム１は、測定した酸素消費量から水素消費量をさらに測定してもよい。本実施形態では、供試体として、ＦＣＶ、すなわち、燃料電池１０１を備えた車両１００を考える。なお、供試体は、燃料電池１０１そのものであってもよいし、燃料電池１０１を備えた車両１００の一部であってもよい。燃料電池１０１を備えた車両１００の一部としては、例えば、燃料電池１０１を備えてはいるものの、市場で販売できる状態まで製造が完成していない未完成の車両を考えることができる。 [1. Overview of the gas measurement system]
FIG. 1 is an explanatory diagram showing a schematic configuration of a gas measurement system 1 of the present embodiment. The gas measurement system 1 is a system for measuring the oxygen consumption of a test specimen. The gas measurement system 1 may further measure the hydrogen consumption from the measured oxygen consumption. In this embodiment, the test specimen is an FCV, that is, a vehicle 100 equipped with a fuel cell 101. The test specimen may be the fuel cell 101 itself, or a part of the vehicle 100 equipped with the fuel cell 101. As a part of the vehicle 100 equipped with the fuel cell 101, for example, an incomplete vehicle that is equipped with the fuel cell 101 but has not been manufactured to a state where it can be sold on the market can be considered.
　燃料電池１０１は、アノード側に供給される燃料ガスである水素と、カソード側に供給される酸化剤ガスである酸素との電気化学反応により発電する。燃料電池１０１は、固体高分子形燃料電池、固体酸化物形燃料電池、リン酸形燃料電池などで構成され得る。 The fuel cell 101 generates electricity through an electrochemical reaction between hydrogen, which is a fuel gas supplied to the anode side, and oxygen, which is an oxidant gas supplied to the cathode side. The fuel cell 101 can be composed of a polymer electrolyte fuel cell, a solid oxide fuel cell, a phosphoric acid fuel cell, or the like.
　ガス測定システム１は、例えば、車両１００をダイナモメータＤＹに搭載して路上走行と同様に走行状態を模擬し、ダイナモメータＤＹにより得られる走行距離、走行時の負荷量等と、水素消費量とに基づき、車両１００の燃費を評価する燃費評価装置等に用いられる。なお、図１中のＡｉｒ１は、車両１００が取り込む大気等を表している。上記のダイナモメータＤＹは、供試体を試験動作させる試験装置である。 The gas measurement system 1 is used, for example, in a fuel efficiency evaluation device that mounts the vehicle 100 on a dynamometer DY to simulate driving conditions similar to those of road driving, and evaluates the fuel efficiency of the vehicle 100 based on the driving distance and load amount during driving obtained by the dynamometer DY, as well as the amount of hydrogen consumed. Note that Air1 in FIG. 1 represents the air taken in by the vehicle 100. The dynamometer DY is a test device that performs test operations on a test specimen.
　ガス測定システム１は、サンプリング機構２を備える。サンプリング機構２は、定容量希釈採取装置（ＣＶＳ）とも呼ばれ、ガス排出路１０２を介して燃料電池１０１から排出されるガス（排ガス）を希釈するとともにサンプリングする。サンプリング機構２は、希釈トンネル２１と、希釈ガス供給路２２と、測定ガスサンプリング部２３と、希釈ガスサンプリング部２４と、を備える。 The gas measurement system 1 includes a sampling mechanism 2. The sampling mechanism 2 is also called a constant volume dilution sampling device (CVS), and dilutes and samples the gas (exhaust gas) discharged from the fuel cell 101 via the gas discharge path 102. The sampling mechanism 2 includes a dilution tunnel 21, a diluted gas supply path 22, a measurement gas sampling unit 23, and a diluted gas sampling unit 24.
　希釈トンネル２１は、ガス排出路１０２と接続される。希釈トンネル２１の下流側、つまり、ガス排出路１０２との接続側とは反対側は、クリティカルフローベンチュリー（臨界ノズル）で形成される。クリティカルフローベンチュリーにより、希釈トンネル２１から排出される排ガスの流量は一定に保たれる。なお、クリティカルフローベンチュリーの代わりに、流路中に流量計を配置する構成でもよい。 The dilution tunnel 21 is connected to the gas exhaust line 102. The downstream side of the dilution tunnel 21, i.e., the side opposite to the side connected to the gas exhaust line 102, is formed by a critical flow venturi (critical nozzle). The critical flow venturi keeps the flow rate of the exhaust gas discharged from the dilution tunnel 21 constant. Note that instead of the critical flow venturi, a configuration in which a flow meter is placed in the flow path may also be used.
　希釈ガス供給路２２は、希釈トンネル２１と接続され、希釈トンネル２１内に希釈ガスを供給する。希釈ガスは大気であり、図１ではＡｉｒ２として示す。希釈トンネル２１内を流れる排ガスは、上記希釈ガスによって希釈される。希釈された排ガスを、希釈排ガスとも称する。希釈トンネル２１内を流れる希釈排ガスは、第１ポンプＰ１の駆動によって排出される。排出される上記希釈排ガスの流量Ｑ１は、クリティカルフローベンチュリーによって規定される。 The diluted gas supply path 22 is connected to the dilution tunnel 21 and supplies diluted gas into the dilution tunnel 21. The diluted gas is air, and is shown as Air2 in FIG. 1. The exhaust gas flowing through the dilution tunnel 21 is diluted by the diluted gas. The diluted exhaust gas is also called diluted exhaust gas. The diluted exhaust gas flowing through the dilution tunnel 21 is discharged by driving the first pump P1. The flow rate Q1 of the discharged diluted exhaust gas is determined by the critical flow venturi.
　測定ガスサンプリング部２３は、希釈トンネル２１から希釈排ガスを測定ガスとしてサンプリングする。測定ガスサンプリング部２３は、測定ガス用サンプリングバッグ２３１と、測定ガス流路２３２と、測定ガス流量制御部２３３と、を備える。 The measurement gas sampling unit 23 samples the diluted exhaust gas from the dilution tunnel 21 as the measurement gas. The measurement gas sampling unit 23 includes a measurement gas sampling bag 231, a measurement gas flow path 232, and a measurement gas flow rate control unit 233.
　測定ガス用サンプリングバッグ２３１は、希釈トンネル２１内で希釈された測定ガスを捕集する。言い換えれば、測定ガス用サンプリングバッグ２３１は、車両１００から排出される排ガスを連続的にサンプリングする第１バックである。測定ガス用サンプリングバッグ２３１は、例えば複数設けられるが、その数は特に限定されない。測定ガス流路２３２は、測定ガス用サンプリングバッグ２３１に捕集された測定ガスを、後述する第１酸素濃度センサ３に導く。測定ガス流量制御部２３３は、測定ガス流路２３２を流れる測定ガスの量を制御する。 The measurement gas sampling bag 231 collects the measurement gas diluted in the dilution tunnel 21. In other words, the measurement gas sampling bag 231 is a first bag that continuously samples the exhaust gas discharged from the vehicle 100. For example, a plurality of measurement gas sampling bags 231 are provided, but the number is not particularly limited. The measurement gas flow path 232 guides the measurement gas collected in the measurement gas sampling bag 231 to the first oxygen concentration sensor 3 described below. The measurement gas flow control unit 233 controls the amount of measurement gas flowing through the measurement gas flow path 232.
　測定ガス流量制御部２３３は、第２ポンプＰ２と、第１流量計ＦＭ１と、測定ガス用開閉弁Ｖ２３と、これらの動作を制御する動作制御部（図示せず）等と、を備えて構成される。第２ポンプＰ２および第１流量計ＦＭ１は、希釈トンネル２１と測定ガス用サンプリングバッグ２３１との間の流路に配置される。測定ガス用開閉弁Ｖ２３は、各測定ガス用サンプリングバッグ２３１の入口側および出口側にそれぞれ設けられる。なお、第１流量計ＦＭ１は、クリティカルフローベンチュリーであってもよい。 The measurement gas flow rate control unit 233 includes a second pump P2, a first flow meter FM1, a measurement gas on-off valve V23 , and an operation control unit (not shown) for controlling the operations of these components. The second pump P2 and the first flow meter FM1 are disposed in a flow path between the dilution tunnel 21 and the measurement gas sampling bag 231. The measurement gas on-off valve V23 is provided on the inlet side and the outlet side of each measurement gas sampling bag 231. The first flow meter FM1 may be a critical flow venturi.
　希釈ガスサンプリング部２４は、希釈ガスのみをサンプリングする。希釈ガスサンプリング部２４は、希釈ガス用サンプリングバッグ２４１と、希釈ガス流路２４２と、希釈ガス流量制御部２４３と、を備える。 The diluted gas sampling unit 24 samples only the diluted gas. The diluted gas sampling unit 24 includes a diluted gas sampling bag 241, a diluted gas flow path 242, and a diluted gas flow control unit 243.
　希釈ガス用サンプリングバッグ２４１は、希釈ガス供給路２２から採取される希釈ガスを捕集する。言い換えれば、希釈ガス用サンプリングバッグ２４１は、大気を連続的にサンプリングする第２バックである。希釈ガス用サンプリングバッグ２４１は、例えば複数設けられるが、その数は特に限定されない。希釈ガス流路２４２は、希釈ガス用サンプリングバッグ２４１に捕集された希釈ガスを、後述する第２酸素濃度センサ５に導く。希釈ガス流量制御部２４３は、希釈ガス流路２４２を流れる希釈ガスの量を制御する。 The diluted gas sampling bag 241 collects the diluted gas taken from the diluted gas supply path 22. In other words, the diluted gas sampling bag 241 is a second bag that continuously samples the atmosphere. For example, multiple diluted gas sampling bags 241 are provided, but the number is not particularly limited. The diluted gas flow path 242 guides the diluted gas collected in the diluted gas sampling bag 241 to the second oxygen concentration sensor 5 described later. The diluted gas flow control unit 243 controls the amount of diluted gas flowing through the diluted gas flow path 242.
　希釈ガス流量制御部２４３は、第３ポンプＰ３と、第２流量計ＦＭ２と、希釈ガス用開閉弁Ｖ２４と、これらの動作を制御する動作制御部（図示せず）等と、を備えて構成される。第３ポンプＰ３および第２流量計ＦＭ２は、希釈ガス供給路２２と希釈ガス用サンプリングバッグ２４１との間の流路に配置される。希釈ガス用開閉弁Ｖ２４は、各希釈ガス用サンプリングバッグ２４１の入口側および出口側にそれぞれ設けられる。なお、第２流量計ＦＭ２は、クリティカルフローベンチュリーであってもよい。 The dilution gas flow rate control unit 243 includes a third pump P3, a second flow meter FM2, a dilution gas on-off valve V24 , and an operation control unit (not shown) for controlling the operations of these components. The third pump P3 and the second flow meter FM2 are disposed in a flow path between the dilution gas supply path 22 and the dilution gas sampling bag 241. The dilution gas on-off valve V24 is provided on the inlet side and the outlet side of each dilution gas sampling bag 241. The second flow meter FM2 may be a critical flow venturi.
　ガス測定システム１は、第１酸素濃度センサ３と、第１リファレンスガス供給部４と、第２酸素濃度センサ５と、第２リファレンスガス供給部６と、をさらに備える。 The gas measurement system 1 further includes a first oxygen concentration sensor 3, a first reference gas supply unit 4, a second oxygen concentration sensor 5, and a second reference gas supply unit 6.
　第１酸素濃度センサ３は、安定性および精度に優れた磁気圧式酸素計で構成されている。磁気圧式酸素計は、前述のように、測定ガスとリファレンスガスとの間の磁化率の差に比例した圧力差から酸素濃度を測定する。したがって、第１酸素濃度センサ３は、車両１００から排出される排ガス中の酸素と、（第１リファレンスガス供給部４から供給される）第１リファレンスガスとの圧力差に基づいて、排ガス中の酸素の濃度を測定する。特に、第１酸素濃度センサ３は、測定ガス用サンプリングバッグ２３１（第１バッグ）に含まれる排ガス中の酸素濃度を測定する。ここで、第１酸素濃度センサ３が測定した酸素濃度を、第２酸素濃度センサ５が測定した酸素濃度と区別するため、第１酸素濃度とも称する。第１リファレンスガスの酸素濃度は、第１所定濃度に設定されているが、第１酸素濃度と第１所定濃度との関係については後述する。測定ガス流路２３２において、第１酸素濃度センサ３に対して測定ガス用サンプリングバッグ２３１とは反対側には、第４ポンプＰ４が配置される。 The first oxygen concentration sensor 3 is composed of a magnetic pressure oxygen meter with excellent stability and accuracy. As described above, the magnetic pressure oxygen meter measures the oxygen concentration from the pressure difference proportional to the difference in magnetic susceptibility between the measurement gas and the reference gas. Therefore, the first oxygen concentration sensor 3 measures the concentration of oxygen in the exhaust gas based on the pressure difference between the oxygen in the exhaust gas discharged from the vehicle 100 and the first reference gas (supplied from the first reference gas supply unit 4). In particular, the first oxygen concentration sensor 3 measures the oxygen concentration in the exhaust gas contained in the measurement gas sampling bag 231 (first bag). Here, the oxygen concentration measured by the first oxygen concentration sensor 3 is also referred to as the first oxygen concentration to distinguish it from the oxygen concentration measured by the second oxygen concentration sensor 5. The oxygen concentration of the first reference gas is set to a first predetermined concentration, and the relationship between the first oxygen concentration and the first predetermined concentration will be described later. In the measurement gas flow path 232, a fourth pump P4 is arranged on the opposite side of the measurement gas sampling bag 231 with respect to the first oxygen concentration sensor 3.
　第１酸素濃度センサ３が、測定ガス用サンプリングバッグ２３１に含まれる排ガス中の酸素濃度を測定することにより、第１酸素濃度として、測定ガス用サンプリングバッグ２３１内で酸素濃度が平均化された値を得ることができる。 The first oxygen concentration sensor 3 measures the oxygen concentration in the exhaust gas contained in the measurement gas sampling bag 231, and the average value of the oxygen concentration in the measurement gas sampling bag 231 can be obtained as the first oxygen concentration.
　第１リファレンスガス供給部４は、第１リファレンスガス収容部４１と、第１リファレンスガス供給路４２と、を有する。第１リファレンスガス収容部４１は、酸素濃度が第１所定濃度である第１リファレンスガスを収容するボンベである。第１リファレンスガス供給路４２は、第１リファレンスガス収容部４１に収容された第１リファレンスガスを第１酸素濃度センサ３に供給する。すなわち、第１リファレンスガス供給部４は、第１リファレンスガスを第１酸素濃度センサ３に供給する。 The first reference gas supply unit 4 has a first reference gas storage unit 41 and a first reference gas supply path 42. The first reference gas storage unit 41 is a cylinder that stores a first reference gas having a first predetermined oxygen concentration. The first reference gas supply path 42 supplies the first reference gas stored in the first reference gas storage unit 41 to the first oxygen concentration sensor 3. In other words, the first reference gas supply unit 4 supplies the first reference gas to the first oxygen concentration sensor 3.
　第２酸素濃度センサ５も第１酸素濃度センサ３と同様に、磁気圧式酸素計で構成されている。第２酸素濃度センサ５は、大気に含まれる酸素と、第２リファレンスガスとの圧力差に基づいて、大気に含まれる酸素の濃度を第２酸素濃度として測定する。特に、第２酸素濃度センサ５は、希釈ガス用サンプリングバッグ２４１（第２バック）に含まれる大気中の酸素濃度を第２酸素濃度として測定する。第２リファレンスガスの酸素濃度は第２所定濃度に設定されているが、第２酸素濃度と第２所定濃度との関係についても後述する。希釈ガス流路２４２において、第２酸素濃度センサ５に対して希釈ガス用サンプリングバッグ２４１とは反対側には、第５ポンプＰ５が配置される。 The second oxygen concentration sensor 5 is also configured as a magnetic pressure type oxygen meter, like the first oxygen concentration sensor 3. The second oxygen concentration sensor 5 measures the concentration of oxygen contained in the atmosphere as a second oxygen concentration based on the pressure difference between the oxygen contained in the atmosphere and the second reference gas. In particular, the second oxygen concentration sensor 5 measures the oxygen concentration in the atmosphere contained in the diluted gas sampling bag 241 (second bag) as the second oxygen concentration. The oxygen concentration of the second reference gas is set to a second predetermined concentration, and the relationship between the second oxygen concentration and the second predetermined concentration will be described later. In the diluted gas flow path 242, a fifth pump P5 is arranged on the opposite side of the diluted gas sampling bag 241 to the second oxygen concentration sensor 5.
　第２酸素濃度センサ５が、希釈ガス用サンプリングバッグ２４１に含まれる大気中の酸素濃度を測定することにより、第２酸素濃度として、希釈ガス用サンプリングバッグ２４１内で酸素濃度が平均化された値を得ることができる。 The second oxygen concentration sensor 5 measures the oxygen concentration in the air contained in the diluted gas sampling bag 241, and the average oxygen concentration value within the diluted gas sampling bag 241 can be obtained as the second oxygen concentration.
　第２リファレンスガス供給部６は、第２リファレンスガス収容部６１と、第２リファレンスガス供給路６２と、を有する。第２リファレンスガス収容部６１は、酸素濃度が第２所定濃度である第２リファレンスガスを収容する。第２リファレンスガス供給路６２は、第２リファレンスガス収容部６１に収容された第２リファレンスガスを第２酸素濃度センサ５に供給する。すなわち、第２リファレンスガス供給部６は、第２リファレンスガスを第２酸素濃度センサ５に供給する。 The second reference gas supply unit 6 has a second reference gas storage unit 61 and a second reference gas supply path 62. The second reference gas storage unit 61 stores a second reference gas having an oxygen concentration of a second predetermined concentration. The second reference gas supply path 62 supplies the second reference gas stored in the second reference gas storage unit 61 to the second oxygen concentration sensor 5. In other words, the second reference gas supply unit 6 supplies the second reference gas to the second oxygen concentration sensor 5.
　ガス測定システム１は、演算部７をさらに備える。演算部７は、少なくとも、クリティカルフローベンチュリーによって規定される排ガス（希釈排ガス）の流量と、第１酸素濃度センサ３で測定された第１酸素濃度とに基づいて、車両１００の水素消費量を算出する。このような演算部７は、例えばＣＰＵ（Central　Processing　Unit）を備える演算装置で構成されており、所定の動作プログラムに従って動作する。上記動作プログラムは、演算装置内の記憶部（図示せず）に記憶される。 The gas measurement system 1 further includes a calculation unit 7. The calculation unit 7 calculates the hydrogen consumption amount of the vehicle 100 based on at least the flow rate of the exhaust gas (diluted exhaust gas) defined by the critical flow venturi and the first oxygen concentration measured by the first oxygen concentration sensor 3. Such a calculation unit 7 is configured as a calculation device equipped with, for example, a CPU (Central Processing Unit), and operates according to a predetermined operation program. The above-mentioned operation program is stored in a memory unit (not shown) in the calculation device.
　特に、演算部７は、第２酸素濃度センサ５の測定値（第２酸素濃度）と、第１酸素濃度センサ３の測定値（第１酸素濃度）と、希釈排ガスの流量と、に基づいて、車両１００の酸素消費量を算出し、算出した酸素消費量に基づいて水素消費量を算出する。 In particular, the calculation unit 7 calculates the oxygen consumption of the vehicle 100 based on the measurement value (second oxygen concentration) of the second oxygen concentration sensor 5, the measurement value (first oxygen concentration) of the first oxygen concentration sensor 3, and the flow rate of the diluted exhaust gas, and calculates the hydrogen consumption based on the calculated oxygen consumption.
　より具体的に説明すると、水素と酸素の反応式は以下の数式（１）に示す通りである。よって、燃料電池１０１で反応して消費された水素の量、つまり、水素消費量ΔＶＨ２（ｍ３）は、数式（２）～（５）によって算出される。
　　２Ｈ２＋Ｏ２＝２Ｈ２Ｏ　　　（１）
　　ΔＶＨ２＝ΔＶＯ２×２　　　（２）
　　ΔＶＯ２＝ＶＡＯ２－ＶＥＯ２　　　（３）
　　ＶＡＯ２＝ＣＡＯ２×ＶＡ　　　（４）
　　ＶＥＯ２＝ＣＥＯ２×ＶＥ×（１／Ｄ）　　　（５） More specifically, the reaction between hydrogen and oxygen is as shown in the following formula (1): Therefore, the amount of hydrogen consumed through the reaction in the fuel cell 101, that is, the hydrogen consumption amount ΔVH 2 (m 3 ), is calculated by formulas (2) to (5).
2H2 + O2 = 2H2O (1)
ΔVH2 = ΔVO2 ×2 (2)
ΔVO2 = VAO2 - VEO2 (3)
VAO2 = CAO2 × VA (4)
VEO2 = CEO2 × VEX × (1/D) (5)
　なお、各パラメータの内訳は、以下の通りである。
　ΔＶＯ２　：酸素消費量ΔＶＯ２（ｍ３）
　ＶＡＯ２　：車両に供給された大気（＝希釈ガス）に含まれる酸素の量（ｍ３）
　ＶＥＯ２　：車両から排出された排ガスに含まれる酸素の量（ｍ３）
　ＣＡＯ２　：希釈ガス用サンプリングバッグ内の平均酸素濃度（ｖｏｌ％）
　ＣＥＯ２　：測定ガス用サンプリングバッグ内の平均酸素濃度（ｖｏｌ％）
　ＶＡ　　：希釈ガスの体積（ｍ３）
　ＶＥ　　：希釈排ガスの体積（ｍ３）
　Ｄ　　　：希釈比（所定時間内での平均値） The breakdown of each parameter is as follows:
ΔVO2 : Oxygen consumption ΔVO2 ( m3 )
VAO2 : The amount of oxygen contained in the air (=dilution gas) supplied to the vehicle ( m3 )
VEO2 : The amount of oxygen contained in the exhaust gas emitted from the vehicle ( m3 )
CAO2 : Average oxygen concentration in the dilution gas sampling bag (vol%)
CEO2 : Average oxygen concentration in the sampling bag for measuring gas (vol%)
VA: Volume of dilution gas (m 3 )
VE: Volume of diluted exhaust gas ( m3 )
D: Dilution ratio (average value within a given time period)
　なお、平均酸素濃度ＣＡＯ２は、第２酸素濃度センサ５で測定される第２酸素濃度であり、平均酸素濃度ＣＥＯ２は、第１酸素濃度センサ３で測定される第１酸素濃度である。また、希釈ガスの体積ＶＡは、第２流量計ＦＭ２で測定する流量（ｍ３／ｍｉｎ）×時間（ｍｉｎ）に相当する。同様に、希釈排ガスの体積ＶＥは、第１流量計ＦＭ１で測定する流量（ｍ３／ｍｉｎ）×時間（ｍｉｎ）に相当する。 The average oxygen concentration CAO2 is the second oxygen concentration measured by the second oxygen concentration sensor 5, and the average oxygen concentration CEO2 is the first oxygen concentration measured by the first oxygen concentration sensor 3. The volume VA of the diluted gas corresponds to the flow rate ( m3 /min) measured by the second flow meter FM2 x time (min). Similarly, the volume VE of the diluted exhaust gas corresponds to the flow rate ( m3 /min) measured by the first flow meter FM1 x time (min).
　なお、この演算の過程で、分圧補正等、より正確な濃度値を求めるための補正を加えることもある。なお、数式（２）～（５）中の体積は、全て標準状態での体積である。 In addition, during this calculation process, corrections such as partial pressure corrections may be made to obtain more accurate concentration values. Note that the volumes in formulas (2) to (5) are all volumes under standard conditions.
　上記の希釈比Ｄは、以下のようにして算出される。図１において、車両１００から排出されて希釈トンネル２１に向かう排ガスの流量を、Ｑ２（ｍ３／ｍｉｎ）とする。また、希釈ガス供給路２２に供給される希釈ガス（大気）の流量を、Ｑ３（ｍ３／ｍｉｎ）とする。車両１００の燃費計測試験では、排ガスの流量Ｑ２は、車両１００のアクセル開度（ダイナモメータＤＹ上で計測される車両１００の車速）に応じて変動する。このため、希釈トンネル２１から排出される希釈排ガスの流量Ｑ１（ｍ３／ｍｉｎ）が一定となるように第１ポンプＰ１を駆動させつつ、排ガスの流量Ｑ２の変動に応じて、希釈ガスの流量Ｑ３を不図示のポンプによって調整する。 The dilution ratio D is calculated as follows. In Fig. 1, the flow rate of exhaust gas discharged from the vehicle 100 and heading toward the dilution tunnel 21 is Q2 ( m3 /min). The flow rate of the diluted gas (air) supplied to the diluted gas supply passage 22 is Q3 ( m3 /min). In a fuel consumption measurement test of the vehicle 100, the flow rate Q2 of the exhaust gas varies depending on the accelerator opening of the vehicle 100 (the vehicle speed of the vehicle 100 measured on the dynamometer DY). For this reason, the first pump P1 is driven so that the flow rate Q1 ( m3 /min) of the diluted exhaust gas discharged from the dilution tunnel 21 is constant, while the flow rate Q3 of the diluted gas is adjusted by a pump (not shown) depending on the variation in the flow rate Q2 of the exhaust gas.
　流量Ｑ２の直接測定には流量計が必要であるが、上記流量計を用いなくても、以下の演算によって流量Ｑ２を求めることができる。すなわち、第１流量計ＦＭ１および第２流量計ＦＭ２で測定される各ガスの流量をそれぞれ、Ｑ４（ｍ３／ｍｉｎ）およびＱ５（ｍ３／ｍｉｎ）とすると、第２ポンプＰ２および第３ポンプＰ３の動作時（サンプリング時）での流量Ｑ２は、以下のように表される。
　Ｑ２＝（Ｑ１＋Ｑ４）－（Ｑ３－Ｑ５） Although a flow meter is necessary to directly measure the flow rate Q2, the flow rate Q2 can be calculated without using the above flow meter by the following calculation: That is, if the flow rates of the gases measured by the first flow meter FM1 and the second flow meter FM2 are Q4 (m 3 /min) and Q5 (m 3 /min), respectively, the flow rate Q2 during operation (sampling) of the second pump P2 and the third pump P3 is expressed as follows:
Q2 = (Q1 + Q4) - (Q3 - Q5)
　したがって、希釈比Ｄは、以下の式で表される。なお、希釈比Ｄは、例えば０．１秒ごとに演算部７によって算出される。このため、所定時間における水素消費量ΔＶＨ２を算出する場合は、上記所定時間での希釈比Ｄの平均値を用いればよい。
　Ｄ　＝（Ｑ１＋Ｑ４）／Ｑ２＝（Ｑ１＋Ｑ４）／｛（Ｑ１＋Ｑ４）－（Ｑ３－Ｑ５）｝ Therefore, the dilution ratio D is expressed by the following formula: The dilution ratio D is calculated by the calculation unit 7, for example, every 0.1 seconds. Therefore, when calculating the amount of hydrogen consumed ΔVH2 in a predetermined time, the average value of the dilution ratio D in the above-mentioned predetermined time can be used.
D = (Q1 + Q4) / Q2 = (Q1 + Q4) / {(Q1 + Q4) - (Q3 - Q5)}
　演算部７は、数式（２）～（５）の演算を行うことにより、酸素バランス法を利用して水素消費量を算出することができる。特に、希釈ガス用サンプリングバッグ２４１（第２バッグ）および測定ガス用サンプリングバッグ２３１（バッグ）内に捕集した希釈ガスおよび希釈排ガスに含まれる酸素の濃度をそれぞれ第２酸素濃度および第１酸素濃度として測定することにより、酸素バランス法の中でも、特にＣＶＳ法によって水素消費量を算出することができる。 The calculation unit 7 can calculate the hydrogen consumption amount using the oxygen balance method by performing the calculations of formulas (2) to (5). In particular, by measuring the concentrations of oxygen contained in the diluted gas and diluted exhaust gas collected in the diluted gas sampling bag 241 (second bag) and the measurement gas sampling bag 231 (bag) as the second oxygen concentration and the first oxygen concentration, respectively, the hydrogen consumption amount can be calculated by the oxygen balance method, particularly the CVS method.
　また、車両１００からの排ガスが、希釈ガス（大気）によって希釈される場合において、演算部７は、希釈比Ｄを加味して、水素消費量を算出する。つまり、演算部７は、第２酸素濃度センサ５の測定値（第２酸素濃度）と、第１酸素濃度センサ３の測定値（第１酸素濃度）と、排ガスの希釈比Ｄと、排ガスの流量とに基づいて、供試体の酸素消費量を算出し、算出した酸素消費量に基づいて水素消費量を算出する。排ガスを希釈する場合に、排ガスの希釈比Ｄをさらに考慮することにより、酸素消費量および水素消費量を適切に算出することができる。 Furthermore, when the exhaust gas from the vehicle 100 is diluted with dilution gas (air), the calculation unit 7 calculates the hydrogen consumption amount taking into account the dilution ratio D. That is, the calculation unit 7 calculates the oxygen consumption amount of the test specimen based on the measurement value (second oxygen concentration) of the second oxygen concentration sensor 5, the measurement value (first oxygen concentration) of the first oxygen concentration sensor 3, the dilution ratio D of the exhaust gas, and the flow rate of the exhaust gas, and calculates the hydrogen consumption amount based on the calculated oxygen consumption amount. When the exhaust gas is diluted, the oxygen consumption amount and hydrogen consumption amount can be appropriately calculated by further taking into account the dilution ratio D of the exhaust gas.
　燃料電池１０１では発電により酸素が消費されるため、車両１００から排出される排ガス中の酸素の濃度（第１酸素濃度）は、車両１００に供給される大気（希釈ガス）中の酸素の濃度（第２酸素濃度）よりも低い。このように、第１酸素濃度と第２酸素濃度とに差が生じるため、演算部７は、数式（２）～（５）に基づいて、水素消費量を確実に算出することができる。 Since oxygen is consumed by the fuel cell 101 to generate electricity, the concentration of oxygen in the exhaust gas discharged from the vehicle 100 (first oxygen concentration) is lower than the concentration of oxygen in the air (diluted gas) supplied to the vehicle 100 (second oxygen concentration). As a result, a difference occurs between the first oxygen concentration and the second oxygen concentration, so the calculation unit 7 can reliably calculate the amount of hydrogen consumed based on formulas (2) to (5).
　供試体は、燃料電池１０１、燃料電池１０１を備えた車両１００、燃料電池１０１を備えた車両１００の一部、のいずれかである。この場合、燃料電池１０１等の水素消費量を算出することができる。 The specimen is either a fuel cell 101, a vehicle 100 equipped with a fuel cell 101, or a part of a vehicle 100 equipped with a fuel cell 101. In this case, the hydrogen consumption of the fuel cell 101, etc. can be calculated.
　演算部７は、水素消費量と供試体の走行距離情報を用いることにより、燃費を計測することができる。走行距離情報は、上述のように、車両１００をダイナモメータＤＹ（図１参照）に搭載して路上走行と同様に走行状態を模擬することによって得られる。供試体が走行できない形態の場合は、供試体の仕事量情報を走行距離情報に換算して燃費を計測してもよい。ここで、仕事量情報とは、供試体が行った単位時間あたりの仕事量の情報を指す。例えば、単位時間あたりＫ（Ｗ）の仕事量で供試体がＮ（ｋｍ）走行することが予め分かっている場合、水素消費量／Ｎ／Ｋを演算することにより、供試体の燃費を計測することができる、つまり、供試体の単位仕事量あたりの消費ガス量を計測することができる。 The calculation unit 7 can measure fuel efficiency by using hydrogen consumption and mileage information of the test specimen. As described above, mileage information is obtained by mounting the vehicle 100 on a dynamometer DY (see FIG. 1) and simulating driving conditions similar to road driving. If the test specimen is in a form that cannot run, the fuel efficiency may be measured by converting the work amount information of the test specimen into mileage information. Here, the work amount information refers to information on the amount of work done by the test specimen per unit time. For example, if it is known in advance that the test specimen will run N (km) with a work amount of K (W) per unit time, the fuel efficiency of the test specimen can be measured by calculating hydrogen consumption/N/K, that is, the amount of gas consumed per unit work amount of the test specimen can be measured.
　また、演算部７は、供試体の仕事量情報を取得し、仕事量情報を用いて単位水素消費量あたりの仕事量を算出してもよい。さらに、演算部７は、ダイナモメータＤＹから供試体の走行距離情報を取得し、取得した走行距離情報に基づいて、単位水素消費量あたりの走行距離を算出してもよい。単位水素消費量あたりの仕事量または単位水素消費量あたりの走行距離を求めることにより、供試体の燃料消費についての分析、評価を行うことができる。 The calculation unit 7 may also acquire work volume information of the test specimen, and use the work volume information to calculate the work volume per unit of hydrogen consumption. Furthermore, the calculation unit 7 may acquire mileage information of the test specimen from the dynamometer DY, and calculate the mileage per unit of hydrogen consumption based on the acquired mileage information. By determining the work volume per unit of hydrogen consumption or the mileage per unit of hydrogen consumption, the fuel consumption of the test specimen can be analyzed and evaluated.
　〔２．第１リファレンスガスおよび第２リファレンスガスの酸素濃度について〕
　上記した第１リファレンスガスの第１所定濃度は、供試体である車両１００（燃料電池１０１）での酸素の消費に伴う酸素濃度の低下量の予測値に基づいて設定される。例えば、大気中に酸素が２１ｖｏｌ％の濃度で含まれており、燃料電池１０１での発電による酸素の消費に伴う酸素濃度の低下量の予測値が１６ｖｏｌ％であった場合、第１リファレンスガスの第１所定濃度は、希釈比Ｄを用いて、例えば２１－１６×（１／Ｄ）に設定される。例えば、希釈比Ｄが１０である場合（排ガスを大気で１０倍に希釈する場合）、第１所定濃度は、２１－１６×（１／１０）＝１９．４ｖｏｌ％に設定される。ここで、第１リファレンスガスの第１所定濃度は、第１酸素濃度センサ３が出力すると予想される第１酸素濃度（例えば１９．４ｖｏｌ％）から、第１所定範囲内に設定される。上記第１所定範囲内とは、第１酸素濃度センサ３が出力すると予想される上記第１酸素濃度から少なくとも１ｖｏｌ％の範囲内であることが望ましく、０．５ｖｏｌ％の範囲内であることがさらに望ましく、０．２ｖｏｌ％の範囲内であることがより望ましいと考える。 2. Oxygen Concentrations of the First Reference Gas and the Second Reference Gas
The first predetermined concentration of the first reference gas is set based on a predicted value of the amount of decrease in oxygen concentration due to oxygen consumption in the vehicle 100 (fuel cell 101) as a test specimen. For example, if oxygen is contained in the atmosphere at a concentration of 21 vol%, and the predicted value of the amount of decrease in oxygen concentration due to oxygen consumption by power generation in the fuel cell 101 is 16 vol%, the first predetermined concentration of the first reference gas is set to, for example, 21-16×(1/D) using the dilution ratio D. For example, if the dilution ratio D is 10 (when the exhaust gas is diluted 10 times with the atmosphere), the first predetermined concentration is set to 21-16×(1/10)=19.4 vol%. Here, the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration (for example, 19.4 vol%) expected to be output by the first oxygen concentration sensor 3. It is considered that the above-mentioned first predetermined range is desirably within a range of at least 1 vol.% from the above-mentioned first oxygen concentration predicted to be output by the first oxygen concentration sensor 3, is further desirably within a range of 0.5 vol.%, and is even more desirably within a range of 0.2 vol.%.
　ここで、上記酸素濃度の低下量の予測値は、例えば、燃料電池１０１または燃料電池１０１を備えた車両１００の性能諸元、性能シミュレーションデータ、事前に予備の試験にて得られた酸素消費量データ等を参照することによって取得することができる。 Here, the predicted value of the decrease in the oxygen concentration can be obtained, for example, by referring to the performance specifications of the fuel cell 101 or the vehicle 100 equipped with the fuel cell 101, performance simulation data, oxygen consumption data obtained in advance from preliminary tests, etc.
　第１酸素濃度センサ３が、排ガス中の酸素と第１リファレンスガスとの圧力差に基づいて、排ガス中の酸素濃度（第１酸素濃度）を測定する構成では、第１酸素濃度と第１リファレンスガスの酸素濃度（第１所定濃度）との差が小さいほど、上記圧力差が小さくなり、第１酸素濃度センサ３の出力信号がゼロに近づく。本実施形態のように。第１リファレンスガスの第１所定濃度が、第１酸素濃度から第１所定範囲内に設定されていることにより、第１酸素濃度と第１所定濃度との差を小さくして上記圧力差をゼロに近づけることができる。これにより、第１酸素濃度センサ３の出力に対して、外乱の影響（例えば圧力、流量、周囲温度の影響）を受けにくくすることができる。したがって、外乱に関係なく、第１酸素濃度センサ３の出力を安定して得ることができる。 In a configuration in which the first oxygen concentration sensor 3 measures the oxygen concentration in the exhaust gas (first oxygen concentration) based on the pressure difference between the oxygen in the exhaust gas and the first reference gas, the smaller the difference between the first oxygen concentration and the oxygen concentration of the first reference gas (first predetermined concentration), the smaller the pressure difference and the closer the output signal of the first oxygen concentration sensor 3 is to zero. As in this embodiment. The first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration, so that the difference between the first oxygen concentration and the first predetermined concentration can be reduced and the pressure difference can be made closer to zero. This makes it possible to make the output of the first oxygen concentration sensor 3 less susceptible to the effects of disturbances (e.g., pressure, flow rate, and ambient temperature). Therefore, the output of the first oxygen concentration sensor 3 can be obtained stably regardless of disturbances.
　特に、車両１００での上記酸素濃度の低下量（上記の例では１６ｖｏｌ％）を前もって予測しておくことにより、上記低下量の予測値に基づいて、上記第１所定濃度を適切に設定することができる。 In particular, by predicting in advance the amount of decrease in the oxygen concentration in the vehicle 100 (16 vol.% in the above example), the first predetermined concentration can be appropriately set based on the predicted amount of decrease.
　また、本実施形態のように、測定ガス用サンプリングバッグ２３１内に希釈排ガス（排ガス）を捕集して第１酸素濃度を測定する構成において、第１酸素濃度センサ３の出力に対する外乱の影響を低減する観点では、第１リファレンスガスの第１所定濃度は、測定ガス用サンプリングバッグ２３１内で平均化された排ガス中の第１酸素濃度と、第１所定範囲内にあることが望ましい。 Furthermore, in a configuration in which diluted exhaust gas (exhaust gas) is collected in the measurement gas sampling bag 231 to measure the first oxygen concentration, as in this embodiment, from the viewpoint of reducing the influence of disturbances on the output of the first oxygen concentration sensor 3, it is desirable that the first predetermined concentration of the first reference gas be within a first predetermined range of the first oxygen concentration in the exhaust gas averaged in the measurement gas sampling bag 231.
　一方、第２リファレンスガスの第２所定濃度は、希釈ガスに含まれる酸素の濃度、つまり、第２酸素濃度センサ５によって測定される第２酸素濃度から第２所定範囲内（例えば１ｖｏｌ％の範囲内）に設定される。例えば、大気中に酸素が２１ｖｏｌ％の濃度で含まれている場合、第２所定濃度は２１ｖｏｌ％に設定される。なお、第２所定濃度は、第２所定範囲内であればよく、例えば２０．５ｖｏｌ％に設定されてもよい。つまり、上記第２所定範囲内は、第２酸素濃度センサ５が出力すると予想される第２酸素濃度（例えば２１ｖｏｌ％）から少なくとも１ｖｏｌ％の範囲内であることが望ましく、０．５ｖｏｌ％の範囲内であることがさらに望ましく、０．２ｖｏｌ％の範囲内であることがより望ましいと考える。 On the other hand, the second predetermined concentration of the second reference gas is set within a second predetermined range (for example, within 1 vol%) from the concentration of oxygen contained in the dilution gas, that is, the second oxygen concentration measured by the second oxygen concentration sensor 5. For example, when oxygen is contained in the atmosphere at a concentration of 21 vol%, the second predetermined concentration is set to 21 vol%. The second predetermined concentration may be set to, for example, 20.5 vol% as long as it is within the second predetermined range. In other words, it is considered that the second predetermined range is preferably within at least 1 vol% from the second oxygen concentration (for example, 21 vol%) expected to be output by the second oxygen concentration sensor 5, more preferably within 0.5 vol%, and even more preferably within 0.2 vol%.
　このような第２所定濃度の設定により、第２酸素濃度と第２所定濃度との差をゼロに近づけて、希釈ガス中の酸素と第２リファレンスガスとの圧力差をゼロに近づけることができる。これにより、第２酸素濃度センサ５の出力に対する外乱の影響を低減することができる。したがって、外乱に関係なく、第２酸素濃度センサ５の出力を安定して得ることができる。特に、第２所定濃度を大気中の酸素の濃度（第２酸素濃度）と等しい値に設定することにより、第２酸素濃度と第２所定濃度との差をゼロにして、第２酸素濃度センサ５の出力に対する外乱の影響を確実に低減することができる。 By setting the second predetermined concentration in this manner, the difference between the second oxygen concentration and the second predetermined concentration can be brought close to zero, and the pressure difference between the oxygen in the diluted gas and the second reference gas can be brought close to zero. This makes it possible to reduce the effects of disturbances on the output of the second oxygen concentration sensor 5. Therefore, a stable output of the second oxygen concentration sensor 5 can be obtained regardless of disturbances. In particular, by setting the second predetermined concentration to a value equal to the concentration of oxygen in the atmosphere (second oxygen concentration), the difference between the second oxygen concentration and the second predetermined concentration can be brought close to zero, and the effects of disturbances on the output of the second oxygen concentration sensor 5 can be reliably reduced.
　第１所定濃度または第２所定濃度は、同じ測定条件で計測したこれまでの測定結果に基づいて設定することもできる。「同じ測定条件」とは、供試体が同一または同型式の別の供試体のあるときの測定条件と同じ条件であってもよいし、本実施形態のガス測定システム１と同一または同様の性能を持つ別のガス測定システムで得られた測定条件と同じ条件であってもよい。「これまでの測定結果」とは、過去の測定結果であり、供試体および／またはガス測定システム１が同一または同型式である別の個体で過去に行われた測定結果である。また、過去とは、実際の測定時と同じ日であっても、測定時よりも前の時点であればよい。したがって、実際の測定時と同じ日であっても、測定時よりも前に予備試験を行って取得した測定結果も、過去の測定結果に含まれる。そうすれば、これから行う測定結果は、過去に行った測定結果と近しい結果値が予期される。このため、過去の測定結果を第１所定濃度または第２所定濃度として利用することができる。なお、過去の測定結果の一例としては、サンプリングバッグ内の濃度値の平均値が挙げられる。 The first or second predetermined concentration can be set based on previous measurement results measured under the same measurement conditions. The "same measurement conditions" may be the same as the measurement conditions when the specimen is the same or another specimen of the same model, or may be the same as the measurement conditions obtained with another gas measurement system having the same or similar performance as the gas measurement system 1 of this embodiment. The "previous measurement results" are past measurement results, and are measurement results previously performed with another specimen and/or gas measurement system 1 of the same model or another individual. In addition, the past may be a time point prior to the measurement, even if it is the same day as the actual measurement. Therefore, even if it is the same day as the actual measurement, a measurement result obtained by performing a preliminary test prior to the measurement is also included in the past measurement results. In this way, the measurement results to be performed in the future are expected to have result values close to the past measurement results. For this reason, the past measurement results can be used as the first or second predetermined concentration. An example of a past measurement result is the average concentration value in the sampling bag.
　以上のことから、本実施形態のガス測定システム１におけるガス測定方法は、以下のように表現することができる。すなわち、第１リファレンスガス供給部４が、酸素濃度が第１所定濃度である第１リファレンスガスを第１酸素濃度センサ３に供給する第１リファレンスガス供給工程と、第１酸素濃度センサ３が、供試体から排出される排ガス中の酸素と、第１リファレンスガスとの圧力差に基づいて、排ガス中の酸素の濃度を第１酸素濃度として測定する第１酸素濃度測定工程と、演算部７が、排ガスの流量と第１酸素濃度とに基づいて、供試体の酸素消費量を算出する演算工程と、を備える。第１リファレンスガスの第１所定濃度は、第１酸素濃度から第１所定範囲内に設定される。 From the above, the gas measurement method in the gas measurement system 1 of this embodiment can be expressed as follows. That is, the method includes a first reference gas supply step in which the first reference gas supply unit 4 supplies a first reference gas having an oxygen concentration of a first predetermined concentration to the first oxygen concentration sensor 3, a first oxygen concentration measurement step in which the first oxygen concentration sensor 3 measures the concentration of oxygen in the exhaust gas discharged from the test specimen as a first oxygen concentration based on the pressure difference between the oxygen in the exhaust gas and the first reference gas, and a calculation step in which the calculation unit 7 calculates the oxygen consumption of the test specimen based on the exhaust gas flow rate and the first oxygen concentration. The first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration.
　〔３．第１酸素濃度センサおよび第２酸素濃度センサの校正について〕
　図２は、図１のガス測定システム１の主要部を示すブロック図である。第１リファレンスガス供給部４は、第１スパン校正用ガス供給路４３をさらに備える。第１スパン校正用ガス供給路４３は、第１リファレンスガス収容部４１に収容された第１リファレンスガスを、第２酸素濃度センサ５に対して、スパン校正用のガスとして供給する流路である。一方、第２リファレンスガス供給部６は、第２スパン校正用ガス供給路６３をさらに備える。第２スパン校正用ガス供給路６３は、第２リファレンスガス収容部６１に収容された第２リファレンスガスを、第１酸素濃度センサ３に対して、スパン校正用のガスとして供給する流路である。 [3. Calibration of the first oxygen concentration sensor and the second oxygen concentration sensor]
Fig. 2 is a block diagram showing main parts of the gas measurement system 1 of Fig. 1. The first reference gas supply unit 4 further includes a first span calibration gas supply path 43. The first span calibration gas supply path 43 is a flow path that supplies the first reference gas accommodated in the first reference gas storage unit 41 to the second oxygen concentration sensor 5 as a gas for span calibration. On the other hand, the second reference gas supply unit 6 further includes a second span calibration gas supply path 63. The second span calibration gas supply path 63 is a flow path that supplies the second reference gas accommodated in the second reference gas storage unit 61 to the first oxygen concentration sensor 3 as a gas for span calibration.
　ここで、燃料電池１０１（図１参照）での発電に伴い、排ガス中の酸素濃度が、大気中の酸素濃度２１ｖｏｌ％から１６ｖｏｌ％低下すると予測し、その後、排ガスを１０倍に希釈することから、第１リファレンスガス収容部４１には、酸素濃度が１９．４ｖｏｌ％付近の第１リファレンスガスが収容されているとする。また、第２リファレンスガス収容部６１には、酸素濃度が２１ｖｏｌ％付近の第２リファレンスガスが収容されているとする。 Here, it is predicted that the oxygen concentration in the exhaust gas will decrease by 16 vol% from the atmospheric oxygen concentration of 21 vol% due to power generation in the fuel cell 101 (see FIG. 1). Since the exhaust gas is then diluted 10 times, the first reference gas storage unit 41 stores a first reference gas with an oxygen concentration of approximately 19.4 vol%. Also, the second reference gas storage unit 61 stores a second reference gas with an oxygen concentration of approximately 21 vol%.
　第１リファレンスガス供給部４は、第１リファレンスガス供給路４２を介して、酸素濃度が１９．４ｖｏｌ％付近の第１リファレンスガスを、第１酸素濃度センサ３に第１リファレンスガスとしてのみならず、ゼロ校正用のガスとしても供給する。また、第１リファレンスガス供給部４は、第１スパン校正用ガス供給路４３を介して、酸素濃度が１９．４ｖｏｌ％付近の第１リファレンスガスを、第２酸素濃度センサ５にスパン校正用のガスとして供給する。 The first reference gas supply unit 4 supplies the first reference gas having an oxygen concentration of approximately 19.4 vol% to the first oxygen concentration sensor 3 not only as the first reference gas but also as a gas for zero calibration via the first reference gas supply path 42. The first reference gas supply unit 4 also supplies the first reference gas having an oxygen concentration of approximately 19.4 vol% to the second oxygen concentration sensor 5 as a gas for span calibration via the first span calibration gas supply path 43.
　一方、第２リファレンスガス供給部６は、第２リファレンスガス供給路６２を介して、酸素濃度が２１ｖｏｌ％付近の第２リファレンスガスを、第２酸素濃度センサ５に第２リファレンスガスとしてのみならず、ゼロ校正用のガスとしても供給する。また、第２リファレンスガス供給部６は、第２スパン校正用ガス供給路６３を介して、酸素濃度が２１ｖｏｌ％付近の第２リファレンスガスを、第１酸素濃度センサ３にスパン校正用のガスとして供給する。 Meanwhile, the second reference gas supply unit 6 supplies the second reference gas having an oxygen concentration of approximately 21 vol% to the second oxygen concentration sensor 5 not only as the second reference gas but also as a gas for zero calibration via the second reference gas supply path 62. In addition, the second reference gas supply unit 6 supplies the second reference gas having an oxygen concentration of approximately 21 vol% to the first oxygen concentration sensor 3 as a gas for span calibration via the second span calibration gas supply path 63.
　つまり、ゼロ校正時に、第１リファレンスガス供給部４は、第１酸素濃度センサ３に第１リファレンスガスを供給し、第２リファレンスガス供給部６は、第２酸素濃度センサ５に第２リファレンスガスを供給する。また、スパン校正時に、第１リファレンスガス供給部４は、第２酸素濃度センサ５に第１リファレンスガスを供給し、第２リファレンスガス供給部６は、第１酸素濃度センサ３に第２リファレンスガスを供給する。 In other words, during zero calibration, the first reference gas supply unit 4 supplies the first reference gas to the first oxygen concentration sensor 3, and the second reference gas supply unit 6 supplies the second reference gas to the second oxygen concentration sensor 5. Also, during span calibration, the first reference gas supply unit 4 supplies the first reference gas to the second oxygen concentration sensor 5, and the second reference gas supply unit 6 supplies the second reference gas to the first oxygen concentration sensor 3.
　これにより、第１リファレンスガスを、第１酸素濃度センサ３のゼロ校正用ガスとしてのみならず、第２酸素濃度センサ５のスパン較正用ガスとして有効利用することができる。また、第２リファレンスガスを、第２酸素濃度センサ５のゼロ校正用ガスとしてのみならず、第１酸素濃度センサ３のスパン較正用ガスとして有効利用することができる。 As a result, the first reference gas can be effectively used not only as a zero calibration gas for the first oxygen concentration sensor 3, but also as a span calibration gas for the second oxygen concentration sensor 5. Also, the second reference gas can be effectively used not only as a zero calibration gas for the second oxygen concentration sensor 5, but also as a span calibration gas for the first oxygen concentration sensor 3.
　〔４．ガス測定システムの他の構成〕
　図３は、ガス測定システム１の他の構成の主要部を示す説明図である。ガス測定システム１は、第１スパン校正用ガス供給路４３および第２スパン校正用ガス供給路６３を設ける代わりに、校正ガス供給部８を設けた以外は、図２の構成と同じである。校正ガス供給部８は、校正ガス収容部８１と、第１校正ガス供給路８２と、第２校正ガス供給路８３と、を有する。校正ガス収容部８１は、酸素濃度が２１ｖｏｌ％付近の第１校正ガスと、酸素濃度が１９．４ｖｏｌ％付近の第２校正ガスと、を別々に収容する。 4. Other configurations of the gas measurement system
Fig. 3 is an explanatory diagram showing main parts of another configuration of the gas measurement system 1. The gas measurement system 1 has the same configuration as that of Fig. 2 except that a calibration gas supply unit 8 is provided instead of the first span calibration gas supply path 43 and the second span calibration gas supply path 63. The calibration gas supply unit 8 has a calibration gas storage unit 81, a first calibration gas supply path 82, and a second calibration gas supply path 83. The calibration gas storage unit 81 separately stores a first calibration gas having an oxygen concentration of about 21 vol% and a second calibration gas having an oxygen concentration of about 19.4 vol%.
　第１校正ガス供給路８２は、第１酸素濃度センサ３に対して、ゼロ校正用ガスとして、酸素濃度が１９．４ｖｏｌ％付近の第２校正ガスを供給し、スパン校正用ガスとして、酸素濃度が２１ｖｏｌ％付近の第１校正ガスを供給する。 The first calibration gas supply path 82 supplies the first oxygen concentration sensor 3 with a second calibration gas having an oxygen concentration of approximately 19.4 vol% as a zero calibration gas, and with a first calibration gas having an oxygen concentration of approximately 21 vol% as a span calibration gas.
　第２校正ガス供給路８３は、第２酸素濃度センサ５に対して、ゼロ校正用ガスとして、酸素濃度が２１ｖｏｌ％付近の第１校正ガスを供給し、スパン校正用ガスとして、酸素濃度が１９．４ｖｏｌ％付近の第２校正ガスを供給する。 The second calibration gas supply path 83 supplies the second oxygen concentration sensor 5 with a first calibration gas having an oxygen concentration of approximately 21 vol% as a zero calibration gas, and with a second calibration gas having an oxygen concentration of approximately 19.4 vol% as a span calibration gas.
　この構成では、校正ガス収容部８１から供給される第２校正ガスによって、第１酸素濃度センサ３のゼロ校正を行うことができるとともに、校正ガス収容部８１から供給される第１校正ガスによって、第１酸素濃度センサ３のスパン校正を行うことができる。また、校正ガス収容部８１から供給される第１校正ガスによって、第２酸素濃度センサ５のゼロ校正を行うことができるとともに、校正ガス収容部８１から供給される第２校正ガスによって、第２酸素濃度センサ５のスパン校正を行うことができる。 In this configuration, the second calibration gas supplied from the calibration gas storage unit 81 can be used to perform zero calibration of the first oxygen concentration sensor 3, and the first calibration gas supplied from the calibration gas storage unit 81 can be used to perform span calibration of the first oxygen concentration sensor 3. In addition, the first calibration gas supplied from the calibration gas storage unit 81 can be used to perform zero calibration of the second oxygen concentration sensor 5, and the second calibration gas supplied from the calibration gas storage unit 81 can be used to perform span calibration of the second oxygen concentration sensor 5.
　図４は、ガス測定システム１のさらに他の構成を示す説明図である。ガス測定システム１は、酸素濃度センサとして、第１酸素濃度センサ３のみを備える。そして、希釈ガス流路２４２が、第１切替バルブＶ１を介して測定ガス流路２３２と接続される。また、第２リファレンスガス供給路６２が、第２切替バルブＶ２を介して第１リファレンスガス供給路４２と接続される。その他の構成は、図１と同じである。 FIG. 4 is an explanatory diagram showing yet another configuration of the gas measurement system 1. The gas measurement system 1 has only a first oxygen concentration sensor 3 as an oxygen concentration sensor. The dilution gas flow path 242 is connected to the measurement gas flow path 232 via a first switching valve V1. The second reference gas supply path 62 is connected to the first reference gas supply path 42 via a second switching valve V2. The other configurations are the same as those in FIG. 1.
　図４の構成では、第１切替バルブＶ１および第２切替バルブＶ２を適切に制御することにより、希釈排ガス中の酸素濃度（第１酸素濃度）の測定と、希釈ガス中の酸素濃度（第２酸素濃度）の測定とを、１つの第１酸素濃度センサ３によって行うことができる。 In the configuration of FIG. 4, by appropriately controlling the first switching valve V1 and the second switching valve V2, it is possible to measure the oxygen concentration in the diluted exhaust gas (first oxygen concentration) and the oxygen concentration in the diluted gas (second oxygen concentration) using a single first oxygen concentration sensor 3.
　〔５．補足〕
　本実施形態では、燃料電池車において、酸素バランス法の中でもＣＶＳ法によって水素消費量を算出するシステムについて説明したが、燃料電池の出力が一定した発電出力の条件下であれば、排ガス流量も概ね一定となる。この場合、第１リファレンスガスの第１所定濃度の設定は、酸素バランス法と直接法とを組み合わせて水素消費量を算出するシステムにも適用することが可能である。例えば、大気中に酸素が２１ｖｏｌ％の濃度で含まれており、燃料電池１０１での発電による酸素の消費に伴う酸素濃度の低下量の予測値が概ね一定であるとして１６ｖｏｌ％であった場合、第１リファレンスガスの第１所定濃度は、例えば２１－１６＝５ｖｏｌ％に設定される。すなわち、この場合でも、第１リファレンスガスの第１所定濃度は、第１酸素濃度センサ３が出力する第１酸素濃度から、第１所定範囲内に設定される。また、この場合でも、上記第１所定範囲内は、第１酸素濃度センサ３が出力すると予想される上記第１酸素濃度から少なくとも１ｖｏｌ％の範囲内であることが望ましく、０．５ｖｏｌ％の範囲内であることがさらに望ましく、０．２ｖｏｌ％の範囲内であることがより望ましいと考える。 [5. Supplementary Information]
In this embodiment, a system for calculating hydrogen consumption by the CVS method among oxygen balance methods in a fuel cell vehicle has been described, but under the condition of a constant power generation output of the fuel cell, the exhaust gas flow rate is also approximately constant. In this case, the setting of the first predetermined concentration of the first reference gas can also be applied to a system for calculating hydrogen consumption by combining the oxygen balance method and the direct method. For example, if oxygen is contained in the atmosphere at a concentration of 21 vol%, and the predicted value of the decrease in oxygen concentration due to the consumption of oxygen by power generation in the fuel cell 101 is approximately constant and is 16 vol%, the first predetermined concentration of the first reference gas is set to, for example, 21-16=5 vol%. That is, even in this case, the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration output by the first oxygen concentration sensor 3. Also, even in this case, it is considered that the first predetermined range is preferably at least within a range of 1 vol% from the first oxygen concentration predicted to be output by the first oxygen concentration sensor 3, more preferably within a range of 0.5 vol%, and even more preferably within a range of 0.2 vol%.
　大気中の酸素濃度は、室内の酸素濃度計測値の平均値情報等であってもよい。 The oxygen concentration in the atmosphere may be information such as the average value of the oxygen concentration measured indoors.
　以上、本発明の実施形態について説明したが、本発明の範囲はこれに限定されるものではなく、発明の主旨を逸脱しない範囲で拡張または変更して実施することができる。 The above describes an embodiment of the present invention, but the scope of the present invention is not limited to this, and can be expanded or modified without departing from the spirit of the invention.
　本発明は、例えばＦＣＶの水素消費量を求めるシステムに利用可能である。 The present invention can be used, for example, in a system that calculates the hydrogen consumption of an FCV.
　　　１　　　ガス測定システム
　　　３　　　第１酸素濃度センサ
　　　４　　　第１リファレンスガス供給部
　　　５　　　第２酸素濃度センサ
　　　６　　　第２リファレンスガス供給部
　　　７　　　演算部
　１００　　　車両（供試体）
　１０１　　　燃料電池（供試体）
　２３１　　　測定ガス用サンプリングバッグ（第１バッグ）
　２４１　　　希釈ガス用サンプリングバッグ（第２バッグ） Reference Signs List 1 Gas measurement system 3 First oxygen concentration sensor 4 First reference gas supply unit 5 Second oxygen concentration sensor 6 Second reference gas supply unit 7 Calculation unit 100 Vehicle (test specimen)
101 Fuel cell (test specimen)
231 Sampling bag for measuring gas (first bag)
241 Sampling bag for dilution gas (second bag)

Claims (16)

  1. 　供試体から排出される排ガス中の酸素と、酸素濃度が第１所定濃度である第１リファレンスガスとの圧力差に基づいて、前記排ガス中の前記酸素の濃度を第１酸素濃度として測定する第１酸素濃度センサと、
    　前記第１リファレンスガスを前記第１酸素濃度センサに供給する第１リファレンスガス供給部と、
    　前記排ガスの流量と前記第１酸素濃度とに基づいて、前記供試体の酸素消費量を算出する演算部と、を備え、
    　前記第１リファレンスガスの前記第１所定濃度は、前記第１酸素濃度から第１所定範囲内に設定される、ガス測定システム。     a first oxygen concentration sensor that measures a concentration of oxygen in the exhaust gas discharged from a test specimen as a first oxygen concentration based on a pressure difference between oxygen in the exhaust gas and a first reference gas having an oxygen concentration of a first predetermined concentration;
    a first reference gas supply unit that supplies the first reference gas to the first oxygen concentration sensor;
    A calculation unit that calculates an oxygen consumption amount of the specimen based on the flow rate of the exhaust gas and the first oxygen concentration,
    The first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration.
  2. 　前記第１所定濃度は、前記供試体での酸素の消費に伴う酸素濃度の低下量の予測値に基づいて設定される、請求項１に記載のガス測定システム。 The gas measurement system of claim 1, wherein the first predetermined concentration is set based on a predicted value of the amount of decrease in oxygen concentration due to oxygen consumption in the test specimen.
  3. 　前記第１所定濃度は、同じ測定条件で計測したこれまでの測定結果に基づいて設定される、請求項１に記載のガス測定システム。 The gas measurement system of claim 1, wherein the first predetermined concentration is set based on previous measurement results measured under the same measurement conditions.
  4. 　前記供試体から排出される前記排ガスを連続的にサンプリングする第１バックをさらに備え、
    　前記第１酸素濃度センサは、前記第１バックに含まれる前記排ガス中の酸素濃度を前記第１酸素濃度として測定する、請求項１から３のいずれかに記載のガス測定システム。     Further comprising a first bag for continuously sampling the exhaust gas discharged from the test specimen;
    4. The gas measurement system according to claim 1, wherein the first oxygen concentration sensor measures an oxygen concentration in the exhaust gas contained in the first bag as the first oxygen concentration.
  5. 　前記第１所定濃度は、前記第１バック内で平均化された前記排ガス中の前記第１酸素濃度と、前記第１所定範囲内にある、請求項３に記載のガス測定システム。 The gas measurement system of claim 3, wherein the first predetermined concentration is within the first predetermined range of the first oxygen concentration in the exhaust gas averaged in the first bag.
  6. 　大気に含まれる酸素と、酸素濃度が第２所定濃度である第２リファレンスガスとの圧力差に基づいて、前記大気に含まれる前記酸素の濃度を第２酸素濃度として測定する第２酸素濃度センサと、
    　前記第２リファレンスガスを前記第２酸素濃度センサに供給する第２リファレンスガス供給部と、をさらに備え、
    　前記第２リファレンスガスの前記第２所定濃度は、前記第２酸素濃度から第２所定範囲内に設定され、
    　前記演算部は、前記第２酸素濃度センサの測定値と、前記第１酸素濃度センサの測定値と、前記流量とに基づいて、前記供試体の水素消費量を算出する、請求項１から５のいずれかに記載のガス測定システム。     a second oxygen concentration sensor that measures the concentration of oxygen contained in the air as a second oxygen concentration based on a pressure difference between oxygen contained in the air and a second reference gas having an oxygen concentration of a second predetermined concentration;
    A second reference gas supply unit that supplies the second reference gas to the second oxygen concentration sensor,
    the second predetermined concentration of the second reference gas is set within a second predetermined range from the second oxygen concentration;
    6. The gas measurement system according to claim 1, wherein the calculation unit calculates the hydrogen consumption amount of the specimen based on the measurement value of the second oxygen concentration sensor, the measurement value of the first oxygen concentration sensor, and the flow rate.
  7. 　前記第２所定濃度は、同じ測定条件で計測したこれまでの測定結果に基づいて設定される、請求項６に記載のガス測定システム。 The gas measurement system of claim 6, wherein the second predetermined concentration is set based on previous measurement results measured under the same measurement conditions.
  8. 　前記大気を連続的にサンプリングする第２バックをさらに備え、
    　前記第２酸素濃度センサは、前記第２バックに含まれる前記大気中の酸素濃度を前記第２酸素濃度として測定する、請求項６または７に記載のガス測定システム。     a second bag for continuously sampling the atmosphere;
    8. The gas measurement system according to claim 6, wherein the second oxygen concentration sensor measures an oxygen concentration in the atmosphere contained in the second bag as the second oxygen concentration.
  9. 　前記演算部は、前記第２酸素濃度センサの測定値と、前記第１酸素濃度センサの測定値と、前記流量とに基づいて、前記供試体の前記酸素消費量を算出し、算出した前記酸素消費量に基づいて前記水素消費量を算出する、請求項８に記載のガス測定システム。 The gas measurement system of claim 8, wherein the calculation unit calculates the oxygen consumption of the specimen based on the measurement value of the second oxygen concentration sensor, the measurement value of the first oxygen concentration sensor, and the flow rate, and calculates the hydrogen consumption based on the calculated oxygen consumption.
  10. 　前記排ガスは、希釈されており、
    　前記演算部は、前記第２酸素濃度センサの測定値と、前記第１酸素濃度センサの測定値と、前記排ガスの希釈比と、前記流量とに基づいて、前記供試体の前記酸素消費量を算出し、算出した前記酸素消費量に基づいて前記水素消費量を算出する、請求項９に記載のガス測定システム。     The exhaust gas is diluted,
    10. The gas measurement system according to claim 9, wherein the calculation unit calculates the oxygen consumption of the specimen based on the measurement value of the second oxygen concentration sensor, the measurement value of the first oxygen concentration sensor, a dilution ratio of the exhaust gas, and the flow rate, and calculates the hydrogen consumption based on the calculated oxygen consumption.
  11. 　前記第１酸素濃度は、前記第２酸素濃度よりも低い、請求項６から１０のいずれかに記載のガス測定システム。 The gas measurement system according to any one of claims 6 to 10, wherein the first oxygen concentration is lower than the second oxygen concentration.
  12. 　ゼロ校正時に、
    　前記第１リファレンスガス供給部は、前記第１酸素濃度センサに前記第１リファレンスガスを供給し、
    　前記第２リファレンスガス供給部は、前記第２酸素濃度センサに前記第２リファレンスガスを供給し、
    　スパン校正時に、
    　前記第１リファレンスガス供給部は、前記第２酸素濃度センサに前記第１リファレンスガスを供給し、
    　前記第２リファレンスガス供給部は、前記第１酸素濃度センサに前記第２リファレンスガスを供給する、請求項６から１１のいずれかに記載のガス測定システム。     During zero calibration,
    the first reference gas supply unit supplies the first reference gas to the first oxygen concentration sensor;
    the second reference gas supply unit supplies the second reference gas to the second oxygen concentration sensor;
    During span calibration,
    the first reference gas supply unit supplies the first reference gas to the second oxygen concentration sensor;
    12. The gas measurement system according to claim 6, wherein the second reference gas supply unit supplies the second reference gas to the first oxygen concentration sensor.
  13. 　前記供試体を試験動作させる試験装置をさらに備え、
    　前記供試体は、燃料電池、前記燃料電池を備えた車両、前記燃料電池を備えた車両の一部、のいずれかである、請求項１から１２のいずれかに記載のガス測定システム。     A test device for performing a test operation on the specimen is further provided,
    13. The gas measurement system according to claim 1, wherein the specimen is any one of a fuel cell, a vehicle equipped with the fuel cell, and a part of a vehicle equipped with the fuel cell.
  14. 　前記演算部は、前記供試体の仕事量情報を取得し、前記仕事量情報を用いて単位水素消費量あたりの仕事量を算出する、請求項１３に記載のガス測定システム。 The gas measurement system of claim 13, wherein the calculation unit acquires workload information of the test specimen and calculates the workload per unit hydrogen consumption using the workload information.
  15. 　前記演算部は、前記供試体の走行距離情報を取得し、前記走行距離情報に基づいて、単位水素消費量あたりの走行距離を算出する、請求項１３または１４に記載のガス測定システム。 The gas measurement system according to claim 13 or 14, wherein the calculation unit acquires mileage information of the test specimen and calculates the mileage per unit hydrogen consumption based on the mileage information.
  16. 　酸素濃度が第１所定濃度である第１リファレンスガスを第１酸素濃度センサに供給する第１リファレンスガス供給工程と、
    　供試体から排出される排ガス中の酸素と、前記第１リファレンスガスとの圧力差に基づいて、前記排ガス中の前記酸素の濃度を第１酸素濃度として測定する第１酸素濃度測定工程と、
    　前記排ガスの流量と前記第１酸素濃度とに基づいて、前記供試体の酸素消費量を算出する演算工程と、を備え、
    　前記第１リファレンスガスの前記第１所定濃度は、前記第１酸素濃度から第１所定範囲内に設定される、ガス測定方法。     a first reference gas supplying step of supplying a first reference gas having an oxygen concentration equal to a first predetermined concentration to a first oxygen concentration sensor;
    a first oxygen concentration measurement step of measuring a concentration of oxygen in the exhaust gas as a first oxygen concentration based on a pressure difference between oxygen in the exhaust gas discharged from a test specimen and the first reference gas;
    A calculation step of calculating an oxygen consumption amount of the specimen based on the flow rate of the exhaust gas and the first oxygen concentration,
    The gas measurement method, wherein the first predetermined concentration of the first reference gas is set within a first predetermined range from the first oxygen concentration.
PCT/JP2023/040601 2022-12-27 2023-11-10 Gas measurement system and gas measurement method WO2024142622A1 (en)

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