Gas analysis device, gas analysis method, and gas analysis system

Abstract

Provided is a portable gas analysis device that analyzes a sample gas, said gas analysis device comprising: an analyzer that analyzes the sample gas; an exhaust line that is connected to the analyzer and that exhausts the sample gas after analysis; a dilution gas introduction line that merges with the exhaust line and that introduces a dilution gas into the exhaust line; and a temperature control mechanism that controls the temperature of the dilution gas flowing through the dilution gas introduction line.

Description

Gas Analyzer, Gas Analysis Method, and Gas Analysis System

[0001] The present invention relates to a portable gas analyzer, a gas analysis method, and a gas analysis system, such as an in-vehicle type.

[0002] Conventionally, in-vehicle gas analyzers have been used to analyze the component concentrations of exhaust gas emitted from vehicles in order to conduct real driving emissions (RDE) tests and the like. Such a gas analyzer includes an analyzer that analyzes the introduced exhaust gas, which is maintained at 100°C or higher to prevent moisture condensation, and an exhaust pump provided downstream of the analyzer. In order to prevent clogging of the exhaust pump by moisture, a drain separator that condenses and removes moisture from the exhaust gas is provided between the analyzer and the exhaust pump.

[0003] International Publication No. WO2023 / 218795

[0004] By the way, in the above-mentioned in-vehicle gas analyzer, further miniaturization and weight reduction are required. However, in the conventional in-vehicle gas analyzer, a drain tank for storing the moisture removed by the drain separator is provided, and the presence of this drain tank has become an obstacle to the miniaturization and weight reduction of the gas analyzer. In addition, in a configuration with such a drain tank, when the drain tank becomes full due to the condensed moisture, it cannot be used any more, so there is another problem that the continuous use time of the gas analyzer is limited. Such problems also apply to portable gas analyzers that can be carried around, regardless of the in-vehicle type.

[0005] The present invention has been made to solve the above-mentioned problems, and in a portable gas analyzer, it is a main object to prevent condensation in the subsequent stage of the analyzer and to achieve a configuration that does not require a drain tank, thereby achieving miniaturization and weight reduction of the entire device.

[0006] In other words, the gas analyzer according to the present invention is a portable device for analyzing a sample gas, and is characterized by comprising: an analyzer for analyzing the sample gas; an exhaust line connected to the analyzer for exhausting the sample gas after analysis; a dilution gas introduction line that joins the exhaust line and introduces a dilution gas into the exhaust line; and a temperature control mechanism for controlling the temperature of the dilution gas flowing through the dilution gas introduction line.

[0007] With this type of system, by introducing a diluent gas into the exhaust line downstream of the analyzer to dilute the sample gas, the moisture concentration in the gas flowing through the exhaust line is reduced, lowering the relative humidity and making condensation less likely. Furthermore, since a temperature-controlled diluent gas is introduced into the exhaust line, introducing a moderately heated diluent gas into the exhaust line increases the amount of saturated water vapor, further lowering the relative humidity and making condensation even less likely. In this way, by introducing a temperature-controlled diluent gas into the exhaust line, the relative humidity of the gas flowing through the exhaust line can be significantly reduced, making condensation less likely. Therefore, a configuration without a drain tank can be used, and the entire device can be made smaller and lighter. Moreover, since condensation is suppressed by diluting the sample gas, it can be suitably used in portable analyzers where it is undesirable to use large pumps and / or large heating elements or other components with high power consumption.

[0008] In a specific embodiment of the gas analyzer, it is preferable that the temperature control mechanism controls the temperature of the diluent gas so that the temperature of the mixed gas, which is a mixture of the sample gas and the diluent gas in the exhaust line, is equal to or above the dew point temperature. This makes it possible to more reliably prevent condensation in the exhaust line.

[0009] One embodiment of the gas analyzer in which the effects of the present invention are particularly evident is one in which an exhaust pump is provided downstream of the point where the exhaust line merges with the dilution gas introduction line.

[0010] Furthermore, it is preferable that the gas analyzer has an insulating material between the analyzer and the dilution gas introduction line. In this way, even if the area around the analyzer is kept at a high temperature using a heater or the like to prevent condensation in the analyzer, the heat will not be transferred to the dilution gas introduction line, making it easier to adjust the dilution gas introduction line to the desired temperature. In addition, by providing an insulating material, heat is prevented from being released from the area around the analyzer, and a heat retention effect is obtained, so power consumption caused by the heater can be reduced.

[0011] Furthermore, it is preferable that the gas analyzer is configured such that the dilution gas introduction line passes through a metal block, and the temperature control mechanism comprises the metal block and a heater for heating the metal block. In this way, the dilution gas introduction line can be temperature-controlled by the metal block, which is heated entirely by the heater, making it easier to control the temperature of the dilution gas to a desired temperature.

[0012] Furthermore, a specific embodiment of the gas analyzer includes a plurality of analyzers of different types, and the dilution gas introduction line includes a plurality of branch lines, the downstream end of the branch lines merging with the exhaust line.

[0013] A specific embodiment of the gas analyzer further includes a pressure regulating valve provided in the dilution gas introduction line and a pressure control unit that adjusts the opening of the pressure regulating valve, wherein the pressure control unit adjusts the opening of the pressure regulating valve so that the flow rate or pressure of the sample gas flowing to the analyzer is within a predetermined range. The gas analyzer of the present invention is portable, and during use, the pressure or flow rate of the introduced sample gas changes depending on the ambient air environment. However, since the pressure control unit adjusts the opening of the pressure regulating valve so that the flow rate or pressure of the sample gas flowing to the analyzer is within a predetermined range, the analyzer can perform stable analysis of the sample gas. This effect is particularly noticeable when used as a vehicle-mounted type where the ambient air environment (e.g., altitude, temperature, etc.) changes moment by moment.

[0014] Furthermore, when multiple analyzers are provided, it is preferable that each of the multiple branch lines is equipped with a pressure regulating valve, and that the pressure control unit adjusts the opening degree of the multiple pressure regulating valves to individually adjust the pressure applied to the multiple analyzers. In this way, the measurement accuracy of each analyzer can be ensured.

[0015] Furthermore, if the plurality of analyzers include a gas analyzer utilizing infrared absorption and an FID analyzer, it is preferable that the pressure control unit controls the opening of the plurality of pressure regulating valves so that the absolute pressure of the sample gas in the gas analyzer utilizing infrared absorption is within a predetermined range, and the differential pressure of the sample gas between the gas inlet and gas outlet sides of the FID analyzer is within a predetermined range. In this way, the sample gas can be analyzed stably in both the gas analyzer utilizing infrared absorption and the FID analyzer, regardless of changes in the ambient air environment.

[0016] Furthermore, it is preferable that the gas analyzer has a buffer tank in the exhaust line, and that the downstream end of the dilution gas introduction line is connected to the buffer tank. In this way, by introducing the dilution gas into the buffer tank, which has a relatively large heat capacity, rather than into the piping that makes up the exhaust line, rapid temperature changes of the sample gas can be prevented, and condensation can be made even less likely to occur. In addition, since the pulsations caused by the operation of the exhaust pump can be removed by the buffer tank, the pressure applied to the analyzer can be controlled with precision.

[0017] Furthermore, a specific embodiment of the gas analyzer is a laser-based gas analyzer that measures the concentration of at least one of the target components in the sample gas, which is carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, formaldehyde, and methane, and comprises a laser light source that irradiates the sample gas with reference light, a photodetector that detects the intensity of the sample light transmitted through the sample gas by the reference light, and a concentration calculation unit that calculates the concentration of the target component based on the output signal of the photodetector, wherein when measuring the concentration of low-concentration carbon monoxide, the concentration calculation unit calculates the concentration based on the absorption of carbon monoxide between 4.74 and 4.76 μm, and when measuring the concentration of high-concentration carbon monoxide, 4. When measuring the concentration of carbon dioxide, the concentration is calculated based on the absorption of carbon monoxide between 90 and 4.92 μm. When measuring the concentration of nitric oxide, the concentration is calculated based on the absorption of carbon dioxide between 4.38 and 4.40 μm. When measuring the concentration of nitric oxide, the concentration is calculated based on the absorption of nitric oxide between 5.14 and 5.17 μm. When measuring the concentration of nitrogen dioxide, the concentration is calculated based on the absorption of nitrogen dioxide between 6.2740 and 6.275 μm. When measuring the concentration of formaldehyde, the concentration is calculated based on the absorption of formaldehyde between 5.65 and 5.68 μm. When measuring the concentration of high concentrations of methane, the concentration is calculated based on the absorption of methane between 7.27 and 7.29 μm.

[0018] Furthermore, the gas analysis method of the present invention is a gas analysis method using a portable gas analyzer comprising an analyzer for analyzing a sample gas, an exhaust line connected to the analyzer for exhausting the sample gas after analysis, and a dilution gas introduction line that joins the exhaust line and introduces a dilution gas into the exhaust line, characterized in that the dilution gas flowing through the dilution gas introduction line is temperature-controlled, and the temperature-controlled dilution gas is introduced into the exhaust line to dilute the sample gas. Such a gas analysis method can achieve the same effects as the gas analyzer of the present invention.

[0019] Furthermore, the gas analysis system of the present invention is a portable system for analyzing a sample gas, and is characterized by comprising: an analyzer for analyzing the sample gas; an exhaust line connected to the analyzer for exhausting the sample gas after analysis; a dilution gas introduction line that joins the exhaust line and introduces a dilution gas into the exhaust line; a temperature control mechanism for controlling the temperature of the dilution gas flowing through the dilution gas introduction line; a calculation unit for calculating the analysis result of the sample gas based on a signal output from the analyzer; and a display unit for displaying the analysis result calculated by the calculation unit. Such a gas analysis system can achieve the same effects and advantages as the gas analyzer of the present invention.

[0020] According to the present invention described above, in a portable gas analyzer, condensation can be prevented downstream of the analyzer, eliminating the need for a drain tank, thereby enabling miniaturization and weight reduction of the entire device.

[0021] A schematic diagram showing the configuration of a gas analyzer according to one embodiment of the present invention. A diagram showing an example of mounting the gas analyzer according to one embodiment of the present invention. A diagram showing an example of mounting the gas analyzer according to one embodiment of the present invention. A schematic diagram showing the configuration of a gas analyzer according to another embodiment. A schematic diagram showing the configuration of a gas analyzer according to another embodiment. A schematic diagram showing the configuration of a gas analysis system according to one embodiment of the present invention. A diagram showing an example of mounting the gas analyzer according to another embodiment.

[0022] A gas analyzer 100 according to one embodiment of the present invention will be described below with reference to the drawings.

[0023] The gas analyzer 100 of this embodiment is a vehicle-mounted type that analyzes the components contained in the exhaust gas emitted from the internal combustion engine of the vehicle, which is the sample gas. Specifically, as shown in Figure 1, the gas analyzer 100 comprises an analyzer 1 for analyzing the sample gas, a sample gas introduction line 2 for introducing the sample gas into the analyzer 1, an exhaust line 3 for exhausting the analyzed sample gas from the analyzer 1, and a dilution gas introduction line 4 for introducing dilution gas into the exhaust line 3. The following describes each part.

[0024] The gas analyzer 100 of this embodiment is equipped with multiple (in this case, two) gas analyzers 1a and 1b of different types, for example, a laser analyzer 1a (also called the first analyzer) using infrared absorption spectroscopy and an FID analyzer 1b (also called the second analyzer) using flame ionization spectroscopy. The first analyzer 1a is equipped with a pressure sensor P1 for measuring the absolute pressure applied to the analyzer. Upstream and downstream of the second analyzer 1b, pressure sensors P2 and P3 are provided for measuring the differential pressure between the gas inlet side and the gas outlet side of the second analyzer 1b. The laser analyzer is temperature-controlled to a predetermined temperature as defined by standards using a temperature control device (not shown). An example of a predetermined temperature is 191°C or 113°C, but other temperatures may also be used.

[0025] Herein, we describe an example of an analysis method using a laser analyzer 1a employing infrared absorption spectroscopy, but this is not an exhaustive example.

[0026] This laser analyzer 1a measures the concentration of a target component in a sample gas, which is at least one of the following: carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, formaldehyde, or methane. The laser analyzer 1a comprises a laser light source (not shown), such as a semiconductor laser, which irradiates the sample gas with reference light; a photodetector (not shown) which detects the intensity of the sample light transmitted through the sample gas; and a concentration calculation unit (not shown) which calculates the concentration of the target component based on the output signal of the photodetector.

[0027] When the laser analyzer 1a measures the concentration of each target component, the laser light source uses infrared light within the following wavelength range as its oscillation wavelength.

[0028] When the component to be measured is carbon monoxide at a low concentration of 100 ppm or less, the laser light source oscillates so that the oscillation wavelength of the laser light includes wavelengths between 4.74 and 4.76 μm. Preferably, it may oscillate so that wavelengths include wavelengths between 4.750 and 4.759 μm. The concentration calculation unit calculates the concentration of carbon monoxide based on the absorption of carbon monoxide in the said wavelength range.

[0029] When the component to be measured is carbon monoxide at a high concentration of 1% or more, the laser light source oscillates so that the oscillation wavelength of the laser light includes wavelengths between 4.90 and 4.92 μm. Preferably, it may oscillate so that wavelengths include wavelengths between 4.905 and 4.915 μm. The concentration calculation unit calculates the concentration of carbon monoxide based on the absorption of carbon monoxide in the said wavelength range.

[0030] When the component to be measured is carbon dioxide, the laser light source oscillates so that the oscillation wavelength of the laser light includes wavelengths between 4.38 and 4.40 μm. Preferably, it may oscillate so that wavelengths include wavelengths between 4.385 and 4.395 μm. The concentration calculation unit calculates the concentration of carbon dioxide based on the absorption of carbon dioxide in the said wavelength range.

[0031] When the component to be measured is nitric oxide, the laser light source oscillates so that the oscillation wavelength of the laser light includes wavelengths between 5.14 and 5.17 μm. Preferably, it may oscillate so that wavelengths include wavelengths between 5.150 and 5.160 μm. The concentration calculation unit calculates the concentration of nitric oxide based on the absorption of nitric oxide in the said wavelength range.

[0032] When the component to be measured is nitrogen dioxide, the laser light source oscillates so that the oscillation wavelength of the laser light includes wavelengths between 6.274 and 6.275 μm. The concentration calculation unit calculates the concentration of nitrogen dioxide based on the absorption of nitrogen dioxide in that wavelength range.

[0033] When the component to be measured is formaldehyde, the laser light source oscillates so that the oscillation wavelength of the laser light includes wavelengths between 5.65 and 5.68 μm. Preferably, it may oscillate so that wavelengths include wavelengths between 5.660 and 5.675 μm. The concentration calculation unit calculates the concentration of formaldehyde based on the absorption of formaldehyde in the said wavelength range.

[0034] When the component to be measured is methane at a high concentration of 1% or more, the laser light source oscillates so that the oscillation wavelength of the laser light includes wavelengths between 7.27 and 7.29 μm. Preferably, it may oscillate so that wavelengths include wavelengths between 7.280 and 7.289 μm. The concentration calculation unit calculates the concentration of methane based on the absorption of methane in the said wavelength range.

[0035] Furthermore, the first analyzer 1a may also utilize the principle of infrared laser absorption modulation (for example, IRLAM), which includes a light source control unit that controls the oscillation and modulation width of the laser light source, and modulates the laser light source so that it falls within the above-mentioned wavelength ranges to measure the concentration of each target component.

[0036] The sample gas introduction line 2 has one end (upstream end) connected to a gas introduction port such as an exhaust pipe that discharges exhaust gas from the vehicle's engine, and the other end (downstream end) connected to the gas introduction section of the analyzer 1. The sample gas introduction line 2 is heated by a heating mechanism (not shown) so that the temperature of the sample gas introduced into the analyzer 1 is above the dew point temperature. The multiple analyzers 1a and 1b may be temperature-controlled to the same temperature or to different temperatures.

[0037] The sample gas introduction line 2 of this embodiment includes a main sampling line 21 connected to the vehicle's exhaust pipe, and a plurality of (in this case, two) branch lines 22a and 22b branching from the downstream end of the main sampling line 21. The downstream ends of each of these branch lines 22a and 22b are connected to the respective analyzers 1a and 1b.

[0038] The exhaust line 3 has one end (upstream end) connected to the gas outlet of the analyzer 1, and the other end (downstream end) is open to the outside. A suction-type exhaust pump 35 is provided in the exhaust line 3. In this embodiment, the exhaust line 3 comprises a plurality of branch lines 31a, 31b, each with its upstream end connected to the gas outlet of the analyzers 1a, 1b, and a combined line 32 formed by the confluence of the branch lines 31a, 31b. The exhaust pump 35 is provided in the combined line 32.

[0039] The dilution gas introduction line 4 has one end (upstream end) open to the outside and the other end (downstream end) connected to the exhaust line 3. The dilution gas introduction line 4 introduces the dilution gas into the exhaust line 3, thereby reducing the relative humidity of the gas flowing through the exhaust line 3 (a mixture of sample gas and dilution gas). As the dilution gas, outside air taken in from the outside may be used, or N2 stored in a gas cylinder may be used. ２ Gas may be used. In the exhaust line 3, the confluence point MP where the dilution gas introduction line 4 joins (which is also the connection point at the downstream end of the dilution gas introduction line 4) is set upstream of the exhaust pump 35. In other words, the exhaust pump 35 is located downstream of the confluence point MP in the exhaust line 3.

[0040] The dilution gas introduction line 4 of this embodiment includes a main intake line 41 whose upstream end is open to the outside, and a plurality of (in this case, two) branch lines 42a and 42b that branch off from the downstream end of the main intake line 41. The downstream ends of each of these branch lines 42a and 42b are connected to locations in the exhaust line 3 corresponding to the plurality of analyzers 1a and 1b. Specifically, one branch line 42a is connected to the merging line 32 downstream of the first analyzer 1a, and the other branch line 42b is connected to a tributary line 31b whose upstream end is connected to the second analyzer 1b. Alternatively, one branch line 42a may be connected to a tributary line 31a whose upstream end is connected to the first analyzer 1a. Furthermore, branch line 42b may be connected to a buffer tank provided in the tributary line 31b.

[0041] Furthermore, each branch line 42a and 42b of the dilution gas introduction line 4 is provided with pressure regulating valves 44a and 44b for adjusting the pressure of the dilution gas.

[0042] The gas analyzer 100 also includes a pressure control unit C that adjusts the flow rate of the dilution gas by adjusting the opening degrees of the pressure regulating valves 44a and 44b, and controls the pressure applied to the plurality of analyzers 1a and 1b. This pressure control unit C is a general-purpose or dedicated computer equipped with a CPU, a memory, an input / output interface, and the like. The pressure control unit C acquires the measured values of the plurality of pressure sensors P1 - P3, and adjusts the opening degree of each of the pressure regulating valves 44a and 44b based on the plurality of measured values. Specifically, the pressure control unit C adjusts so that the absolute pressure (the measured value of the pressure sensor P1) applied to the first analyzer 1a, which is a laser analyzer, is within a predetermined range, preferably substantially constant, and the differential pressure between the upstream and downstream of the second analyzer 1b, which is an FID analyzer (the difference between the measured values of the pressure sensors P2 and P3), is within a predetermined range, preferably substantially constant, and adjusts the opening degrees of the pressure regulating valves 44a and 44b.

[0043] Specifically, when the outside air pressure of the gas analyzer 100 fluctuates, the pressure applied to the analyzer 1 fluctuates, and it becomes impossible to introduce a constant flow rate of exhaust gas into the analyzer 1. Therefore, for example, when making the differential pressure applied to the analyzer 1 constant, the introduction amount of the dilution gas is adjusted according to the pressure in the front stage of the analyzer 1 (for example, when the pressure increases, the introduction amount of the dilution gas is increased to raise the pressure in the rear stage of the analyzer 1), so that the absolute pressure and / or differential pressure applied to the analyzer is made constant.

[0044] As described above, in the gas analyzer 100 of this embodiment, the sample gas collected in the main sampling line 21 branches into a plurality (here, two) of flow paths 22a and 22b and is introduced into the analyzers 1a and 1b. The sample gas analyzed by the analyzers 1a and 1b is discharged from the gas outlet portions of the analyzers 1a and 1b to the exhaust line 3.

[0045] On the other hand, the dilution gas is introduced from the dilution gas introduction line 4 and branched according to the number of analyzers 1. The pressure applied to the analyzer 1 or the differential pressure before and after the analyzer 1 is adjusted according to the type of the analyzer 1 by the pressure regulating valve 44 arranged in the branch line 42. At this time, the flow rate of the dilution gas fluctuates due to the pressure regulating valve 44 arranged in the branch line 42. In other words, the flow rate of the dilution gas and the pressure applied to the analyzer or the differential pressure before and after the analyzer are adjusted simultaneously by the pressure regulating valve. The sample gas discharged into the exhaust line 3 is diluted with the dilution gas at the confluence point MP placed downstream of the analyzers 1a and 1b to become a mixed gas. The mixed gas is sucked by the exhaust pump 35, exits the exhaust port, and is exhausted into the atmosphere. At this time, the moisture contained in the mixed gas is also released into the atmosphere. Depending on the environment outside the analyzer 100, moisture may condense when the mixed gas is released into the atmosphere, but it does not affect the inside of the analyzer 100.

[0046] Thus, the gas analyzer 100 of the present embodiment further includes a temperature control mechanism 5 for temperature-controlling the dilution gas flowing through the dilution gas introduction line 4.

[0047] This temperature control mechanism 5 temperature-controls the dilution gas flowing through the dilution gas introduction line 4 so that the temperature of the mixed gas in which the sample gas and the dilution gas are mixed in the exhaust line 3 is above the dew point. More specifically, the temperature control mechanism 5 temperature-controls the dilution gas so that the temperature of the mixed gas flowing between the confluence point MP with the dilution gas line and the exhaust pump 35 in the exhaust line 3 is above the dew point temperature.

[0048] In this embodiment, at least a portion of the dilution gas introduction line 4 passes through the inside of a metal block 51 made of a predetermined metal (for example, a metal material such as stainless steel or aluminum). Specifically, the flow path of the dilution gas introduction line 4 is formed by tunnel-shaped holes formed inside the metal block 51. The temperature control mechanism 5 includes the metal block 51, a heater for heating the metal block 51, and a temperature control unit (not shown) for controlling the temperature of the heater, and is adjusted so that the entire metal block 51 is at approximately the same temperature. Specifically, the temperature of the entire metal block 51 is adjusted so that the temperature of the mixed gas when the dilution gas and sample gas are mixed is at or above the dew point temperature of the mixed gas. In this embodiment, the heater is a cartridge heater inserted into the metal block 51, but is not limited to this.

[0049] The temperature control mechanism 5 of this embodiment is configured to control the temperature of a portion of the main intake line 41 in the gas introduction line 4, the entirety of the multiple branch lines 42a and 42b, and a portion of the confluence line of the exhaust line 3, at least the portion including the confluence point MP. In this embodiment, the temperature control mechanism 5 adjusts each line to approximately the same temperature, but it may also be configured to adjust each line to a different temperature.

[0050] In this embodiment, an insulating material 6 is provided between the analyzer 1 and the dilution gas line. Specifically, in this embodiment, the analyzer 1 is housed in a casing having a wall containing the insulating material 6, and the analyzer 1 and the dilution gas line are spatially separated by this wall.

[0051] With the gas analyzer 100 of this embodiment configured in this way, by introducing a diluent gas into the exhaust line 3 downstream of the analyzer 1, the relative humidity can be lowered by reducing the water vapor concentration in the gas flowing through the exhaust line 3, making condensation less likely to occur. Furthermore, since a temperature-controlled diluent gas is introduced into the exhaust line 3, introducing a moderately heated diluent gas into the exhaust line 3 increases the saturated water vapor content, further lowering the relative humidity and making condensation even less likely to occur. Moreover, the temperature control mechanism 5 controls the temperature of the diluent gas so that the temperature of the mixed gas, which is a mixture of the sample gas and the diluent gas in the exhaust line 3, is above the dew point temperature, thus reliably preventing condensation in the exhaust line 3. As a result, a configuration without a drain tank in the exhaust line 3 can be adopted, making the entire device smaller and lighter.

[0052] Furthermore, since an insulating material 6 is provided between the analyzer 1 and the dilution gas introduction line 4, heat near the analyzer 1 is prevented from being transferred to the dilution gas introduction line 4, making it easier to adjust the dilution gas introduction line 4 to the desired temperature. In addition, by providing the insulating material 6, heat is prevented from being released from near the analyzer 1, and a heat retention effect is obtained, thus reducing power consumption caused by the heater.

[0053] Furthermore, the dilution gas introduction line 4 is provided to pass through the metal block 51, and the temperature control mechanism 5 includes the metal block 51 and a heater for heating the metal block 51. Therefore, the dilution gas introduction line 4 can be temperature-controlled by the metal block 51, which is heated entirely by the heater, making it easier to temperature-control the dilution gas to a desired temperature.

[0054] Furthermore, by using the exhaust pump 35 installed in the exhaust line 3 to draw in the mixed gas, the pressure inside the exhaust line 3 can be reduced, thereby making it even less likely for condensation to occur.

[0055] It should be noted that the present invention is not limited to the embodiments described above. For example, the gas analyzer 100 in the above embodiment was a vehicle-mounted type, but it is not limited to this. The gas analyzer 100 in other embodiments does not have to be a stationary type, but can be portable. For example, it may be something that a person can carry. In this case, the sample gas to be analyzed is not limited to exhaust gas from a vehicle, but may be combustion exhaust gas, exhaust gas from a plant, atmospheric air and / or air in a laboratory, etc.

[0056] If the gas analyzer 100 is a vehicle-mounted type, it may be installed inside the vehicle V as shown in Figure 2, or it may be fixedly attached to the outside of the vehicle V using a carrier member such as a hitch carrier, as shown in Figure 3.

[0057] Furthermore, in the above embodiment, the dilution gas introduction line 4 was branched and the dilution gas was introduced from a point corresponding to each analyzer 1 in the exhaust line 3, but it is not limited to this. That is, the dilution gas introduction line 4 was equipped with branch lines 42 corresponding to the number of analyzers 1, but it is not limited to this. In other embodiments, the number of branch lines 42 may be less than the number of analyzers 1. For example, it is not necessary to merge the branch lines 42 with each tributary line 31.

[0058] In another embodiment of the gas analyzer 100, as shown in Figure 4, a buffer tank 33 may be provided upstream of the exhaust pump 35 in the exhaust line 3. In this case, the downstream ends of each of the multiple branch lines 31a and 31b are connected to the buffer tank 33, and the sample gas that has passed through each analyzer 1a and 1b may merge in the buffer tank 33. In this case, one of the branch lines 42a of the dilution gas introduction line 4 may be connected to the buffer tank 33 provided in the exhaust line 3. That is, in this case, the buffer tank 33 functions as a confluence point MP of the dilution gas and the sample gas. Note that the branch line 42b may be connected to a buffer tank separately provided in the branch line 31b.

[0059] Furthermore, in the above embodiment, exhaust gas discharged from an internal combustion engine such as a vehicle engine was used as the sample gas, but it is not limited to this. The sample gas may be exhaust gas discharged from an internal combustion engine other than a vehicle, for example, exhaust gas discharged from an internal combustion engine of a mobile body such as a ship or aircraft, or exhaust gas discharged from an internal combustion engine of various factories or industrial facilities. The sample gas may also be gas discharged from sources other than internal combustion engines in research facilities, industrial facilities, experimental facilities, or factories. Examples of industrial facilities include, but are not limited to, sewage treatment plants, incineration plants, industrial waste treatment plants, power plants, chemical plants, gas refineries, petroleum refineries, semiconductor factories, or various gas manufacturing facilities. When analyzing exhaust gas from sources other than vehicles, a drain tank may be provided at the exhaust port (not shown) at the lower end of the exhaust line 3. Depending on the operating environment of the analyzer 100, such as when used in a low-temperature location, condensation may occur in the mixed gas when it is exhausted from the analyzer 100. In this case, a drain tank and / or a drain separator may be connected to the exhaust port of the analyzer 1 to temporarily store the condensed water, or the exhaust port may be connected to a drain or the like to directly drain the condensed water. In another embodiment, the sample gas may be measured as is without dilution, or the sample gas may be diluted before being introduced into the analyzer 100.

[0060] Furthermore, although the gas analyzer 100 in the above embodiment was equipped with multiple analyzers 1, in other embodiments, for example as shown in Figure 5, the gas analyzer 100 may be equipped with only one analyzer 1. In this case, the downstream end of the main sampling line 21 is connected to the gas inlet of the analyzer 1, and a dilution gas introduction line 4 may be connected to the exhaust line 3 which is connected to the gas outlet of the analyzer 1, and a dilution gas may be introduced. In addition, a buffer tank may be placed at the confluence point MP of the exhaust line 3 and the dilution gas introduction line 4, or between the confluence point MP and the pump 35.

[0061] In other embodiments, at least one of the first analyzer 1a and the second gas analyzer may be another analyzer that utilizes light absorption, such as FTIR, NDIR, or NDUV.

[0062] In other embodiments, the temperature control mechanism 5 for controlling the temperature of the dilution gas introduction line 4 does not necessarily have to use a metal block 51. For example, it may be directly heated by a heater.

[0063] In another embodiment, the insulating material 6 may not be provided between the analyzer 1 and the dilution gas line.

[0064] Furthermore, as shown in Figure 6, the disclosure of this specification may also include a gas analysis system S comprising the analyzer 1 described above, a calculation unit A that calculates the analysis result of the sample gas based on the signal output from the analyzer 1, and a display unit D that displays the analysis result calculated by the calculation unit. The gas analysis system S may also include a central control unit G that controls the analyzer 1, the pressure control valve 44, and each pump 35. The calculation unit A and the display unit D may be included in the gas analysis apparatus 100 described above, or they may be separate from the gas analysis apparatus 100. The gas analysis system S may also include a flow meter (not shown) that measures the flow rate of the sample gas discharged from the vehicle. In this case, the calculation unit A may calculate the total amount of the target component contained in the sample gas discharged from the vehicle from the sample gas flow rate calculated by the flow meter and the concentration of the target component measured by the analyzer.

[0065] In another embodiment, as shown in Figure 7, the gas analyzer 100 may be mounted on a vehicle V placed on a chassis dynamometer 200 and used in bench testing. The chassis dynamometer 200 includes a front wheel roller 210 on which the front wheels of the vehicle V are placed, a rear wheel roller 220 on which the rear wheels of the vehicle V are placed, and dynamometers 230 and 240 that input loads to the front wheel roller 210 and the rear wheel roller 220, respectively. The dynamometers 230 and 240 are feedback controlled by a dynamometer control unit 250 that inputs a predetermined load command value, for example, based on a predetermined driving pattern. In the case of a front-wheel-drive vehicle under test, the rear wheel roller 220 and dynamometer 240 may be omitted. In this embodiment, the sample gas introduced into the gas analyzer 100 may be not only gas emitted from the vehicle V, but also gas directly sampled from the engine.

[0066] Furthermore, while the exhaust gas analysis system S of the above embodiment tested the vehicle V using a chassis dynamometer 200, it may also be used to test the performance of the engine using an engine dynamometer, or to test the performance of the powertrain using a dynamometer. In this case, the generated sample gas may be introduced directly or diluted into the gas analyzer 100 for analysis of the sample gas.

[0067] In another embodiment of the exhaust gas analysis system S, the exhaust gas discharged from the test specimen may be introduced into an exhaust gas sampling device, uniformly mixed with diluted air to dilute it, and then introduced into the gas analyzer 100.

[0068] Alternatively, a pressure control valve may be provided upstream of the analyzer 1 to adjust the pressure upstream of the analyzer 1 to be within a predetermined range. In this case as well, the differential pressure and / or absolute pressure applied to the analyzer 1 may be adjusted by introducing a dilution gas downstream of the analyzer 1 from the dilution gas introduction line 4. Any type of pressure control valve may be used.

[0069] Furthermore, various modifications and combinations of the embodiments are permitted, as long as they do not contradict the spirit of the present invention.

[0070] According to the present invention, in a portable gas analyzer, condensation can be prevented downstream of the analyzer, eliminating the need for a drain tank, thereby enabling miniaturization and weight reduction of the entire device.

[0071] 100...Gas analyzer 1...Analyzer 2...Sample gas introduction line 21...Main sampling line 22a, b...Branch line 3...Exhaust line 31a, b...Tributary line 32...Confluence line 33...Buffer tank 35...Exhaust pump 4...Dilution gas introduction line 41...Main intake line 42...Branch line 44a, b...Pressure control valve 5...Temperature control mechanism 51...Metal block 6...Insulation material

Claims

1. A portable gas analyzer for analyzing a sample gas, comprising: an analyzer for analyzing the sample gas; an exhaust line connected to the analyzer for exhausting the sample gas after analysis; a dilution gas introduction line that joins the exhaust line and introduces a dilution gas into the exhaust line; and a temperature control mechanism for controlling the temperature of the dilution gas flowing through the dilution gas introduction line.

2. The gas analyzer according to claim 1, wherein the temperature control mechanism controls the temperature of the dilution gas so that the temperature of the mixed gas, which is obtained by mixing the sample gas and the dilution gas in the exhaust line, is equal to or above the dew point temperature.

3. The gas analyzer according to claim 1 or 2, wherein the exhaust pump is provided downstream of the point where the exhaust line merges with the dilution gas introduction line.

4. The gas analyzer according to any one of claims 1 to 3, wherein an insulating material is provided between the analyzer and the dilution gas introduction line.

5. The gas analyzer according to any one of claims 1 to 4, wherein the dilution gas introduction line is provided to pass through a metal block, and the temperature control mechanism comprises the metal block and a heater for heating the metal block.

6. The gas analyzer according to any one of claims 1 to 5, comprising a plurality of analyzers of different types, wherein the dilution gas introduction line comprises a plurality of branch lines, and the downstream end of the branch line merges with the exhaust line.

7. The gas analyzer according to any one of claims 1 to 6, further comprising: a pressure regulating valve provided in the dilution gas introduction line; and a pressure control unit that adjusts the opening degree of the pressure regulating valve, wherein the pressure control unit adjusts the opening degree of the pressure regulating valve so that the flow rate or pressure of the sample gas flowing to the analyzer is within a predetermined range.

8. The gas analyzer according to claim 7, which references claim 6, wherein each of the plurality of branch lines is provided with the pressure regulating valve, and the pressure control unit adjusts the opening degree of the plurality of pressure regulating valves to individually adjust the pressure applied to the plurality of analyzers.

9. The gas analyzer according to claim 8, wherein the plurality of analyzers include a gas analyzer utilizing infrared absorption and an FID analyzer, and the pressure control unit controls the opening of the plurality of pressure regulating valves so that the absolute pressure of the sample gas in the gas analyzer utilizing infrared absorption is within a predetermined range and the differential pressure of the sample gas between the gas inlet side and the gas outlet side of the FID analyzer is within a predetermined range.

10. A gas analyzer according to any one of claims 1 to 9, wherein a buffer tank is provided in the exhaust line, and the downstream end of the dilution gas introduction line is connected to the buffer tank.

11. The analyzer is an infrared light source gas analyzer that measures the concentration of a target component in the sample gas, which is at least one of carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, formaldehyde, and methane, comprising: an infrared light source that irradiates the sample gas with reference light; a photodetector that detects the intensity of the sample light transmitted through the sample gas by the reference light; and a concentration calculation unit that calculates the concentration of the target component based on the output signal of the photodetector, wherein the concentration calculation unit calculates the concentration based on the absorption of carbon monoxide between 4.74 and 4.76 μm when measuring a low concentration of carbon monoxide; calculates the concentration based on the absorption of carbon monoxide between 4.90 and 4.92 μm when measuring a high concentration of carbon monoxide; calculates the concentration based on the absorption of carbon dioxide between 4.38 and 4.40 μm when measuring a carbon dioxide concentration; and calculates the concentration based on the absorption of nitric oxide between 5.14 and 5.17 μm when measuring a nitric oxide concentration. A gas analyzer according to any one of claims 1 to 10, wherein when measuring the concentration of nitrogen dioxide, the concentration is calculated based on the absorption of nitrogen dioxide between 6.274 and 6.275 μm; when measuring the concentration of formaldehyde, the concentration is calculated based on the absorption of formaldehyde between 5.65 and 5.68 μm; and when measuring the concentration of high concentrations of methane, the concentration is calculated based on the absorption of methane between 7.27 and 7.29 μm.

12. A gas analysis method using a portable gas analyzer comprising an analyzer for analyzing a sample gas, an exhaust line connected to the analyzer for exhausting the sample gas after analysis, and a dilution gas introduction line that joins the exhaust line for introducing a dilution gas into the exhaust line, wherein the dilution gas flowing through the dilution gas introduction line is temperature-controlled, and the temperature-controlled dilution gas is introduced into the exhaust line to dilute the sample gas.

13. A portable gas analysis system for analyzing a sample gas, comprising: an analyzer for analyzing the sample gas; an exhaust line connected to the analyzer for exhausting the sample gas after analysis; a dilution gas introduction line that joins the exhaust line and introduces a dilution gas into the exhaust line; a temperature control mechanism for controlling the temperature of the dilution gas flowing through the dilution gas introduction line; a calculation unit for calculating the analysis result of the sample gas based on a signal output from the analyzer; and a display unit for displaying the analysis result calculated by the calculation unit.

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