WO2013099923A1 - ガス濃度推定装置 - Google Patents
ガス濃度推定装置 Download PDFInfo
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- WO2013099923A1 WO2013099923A1 PCT/JP2012/083607 JP2012083607W WO2013099923A1 WO 2013099923 A1 WO2013099923 A1 WO 2013099923A1 JP 2012083607 W JP2012083607 W JP 2012083607W WO 2013099923 A1 WO2013099923 A1 WO 2013099923A1
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- plasma
- concentration
- emission
- gas
- analysis
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- 238000004458 analytical method Methods 0.000 claims abstract description 88
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 106
- 239000001569 carbon dioxide Substances 0.000 claims description 53
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 53
- 229930195733 hydrocarbon Natural products 0.000 claims description 19
- 150000002430 hydrocarbons Chemical class 0.000 claims description 19
- 238000011088 calibration curve Methods 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 8
- 238000011144 upstream manufacturing Methods 0.000 claims description 7
- 238000002485 combustion reaction Methods 0.000 claims description 2
- 239000007789 gas Substances 0.000 description 86
- 230000003287 optical effect Effects 0.000 description 20
- 238000012986 modification Methods 0.000 description 12
- 239000004215 Carbon black (E152) Substances 0.000 description 11
- 239000013307 optical fiber Substances 0.000 description 9
- 230000004048 modification Effects 0.000 description 8
- 125000004429 atom Chemical group 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 125000004432 carbon atom Chemical group C* 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000284 extract Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000001499 laser induced fluorescence spectroscopy Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 150000001721 carbon Chemical group 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 230000004043 responsiveness Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/66—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light electrically excited, e.g. electroluminescence
- G01N21/68—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light electrically excited, e.g. electroluminescence using high frequency electric fields
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/66—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light electrically excited, e.g. electroluminescence
- G01N21/67—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light electrically excited, e.g. electroluminescence using electric arcs or discharges
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0062—General constructional details of gas analysers, e.g. portable test equipment concerning the measuring method or the display, e.g. intermittent measurement or digital display
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2247—Sampling from a flowing stream of gas
- G01N1/2252—Sampling from a flowing stream of gas in a vehicle exhaust
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/85—Investigating moving fluids or granular solids
- G01N2021/8578—Gaseous flow
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/067—Electro-optic, magneto-optic, acousto-optic elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/004—CO or CO2
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Definitions
- the present invention relates to a gas concentration estimation device and a gas concentration estimation method for estimating the concentration of a target component in an analysis gas by analyzing light emitted from the plasma of the analysis gas.
- Japanese Patent Laid-Open No. 9-304280 discloses this type of gas concentration estimation apparatus.
- Japanese Patent Laid-Open No. 9-304280 describes a method for measuring the concentration of carbon dioxide using a laser-induced fluorescence method.
- this concentration measurement method allows a plurality of photons to be absorbed by carbon dioxide molecules at once. Yes.
- the conventional gas concentration estimation apparatus has a problem that a special light receiver is required to obtain the emission intensity of the wavelength component corresponding to the emission of carbon dioxide, which is the target component, and lacks versatility.
- the present invention has been made in view of the above points, and its purpose is to provide a general-purpose gas concentration estimation apparatus that estimates the concentration of a target component in an analysis gas by analyzing light emitted from plasma of the analysis gas.
- the object is to realize a gas concentration estimating apparatus having a characteristic.
- plasma generation means for bringing an analysis gas into a plasma state, and analysis for estimating a concentration of a target component in the analysis gas by analyzing plasma light emitted from the plasma generated by the plasma generation means
- a gas concentration estimation device The analysis means of the gas concentration estimation apparatus emits light of a wavelength component corresponding to light emission of a predetermined radical including atoms or molecules separated from the target component in the plasma light having an atomic configuration different from that of the target component. Based on the intensity, the concentration of the target component is estimated.
- the concentration of the target component in the analysis gas is estimated by analyzing the plasma light emitted from the plasma of the analysis gas.
- the concentration of the target component is estimated based on the emission intensity of the wavelength component corresponding to the emission of a predetermined radical in the plasma.
- the predetermined radical is a predetermined radical containing an atom or molecule separated from the target component with an atomic configuration different from that of the target component. For example, when carbon dioxide is a target component, a CN radical containing a carbon atom separated from carbon dioxide molecules becomes a predetermined radical.
- the analyzing means estimates the concentration of carbon dioxide as the target component based on the emission intensity of the wavelength component corresponding to the emission of the CN radical in the plasma light. To do.
- the emission intensity of the CN radical contained in the plasma light of the analysis gas correlates with the concentration of carbon dioxide, so the wavelength corresponding to the emission of the CN radical.
- the concentration of carbon dioxide is estimated based on the emission intensity of the component.
- the exhaust gas discharged after combustion of hydrocarbons is used as the analysis gas, and carbon dioxide in the analysis gas is used as the target component, while the analysis means includes the exhaust gas.
- the concentration of unburned hydrocarbon in the gas is estimated, and the estimated result is used to correct the estimated concentration of carbon dioxide based on the emission intensity of the wavelength component corresponding to the emission of the CN radical.
- the concentration of carbon dioxide estimated based on the emission intensity of the wavelength component corresponding to the emission of the CN radical is corrected using the estimation result of the unburned hydrocarbon concentration in the exhaust gas.
- the concentration of carbon dioxide estimated from only the emission intensity of the wavelength component corresponding to the emission of the CN radical may cause an error with respect to the actual value.
- the concentration of carbon dioxide is corrected using the estimation result of the concentration of hydrocarbon.
- the analyzing means estimates the concentration of unburned hydrocarbons based on the emission intensity of the wavelength component corresponding to the emission of the CH radical in the emission of the plasma. .
- the unburned hydrocarbon concentration is estimated based on the emission intensity of the wavelength component corresponding to the emission of the CH radical.
- the analyzing means uses a calibration curve representing the relationship between the emission intensity of the wavelength component corresponding to the emission of the CN radical and the concentration of carbon dioxide.
- concentration of carbon dioxide is estimated from the emission intensity of the wavelength component corresponding to the emission of the CN radical.
- the emission intensity of the wavelength component corresponding to the emission of the CN radical is Concentration is estimated.
- the analyzing means estimates a concentration of water vapor as the target component based on a light emission intensity of a wavelength component corresponding to light emission of OH radicals among light emission of the plasma. To do.
- the emission intensity of OH radicals contained in the plasma light of the analysis gas correlates with the concentration of water vapor, so that the wavelength component corresponding to the emission of OH radicals Based on the emission intensity, the concentration of water vapor is estimated.
- the flow rate detecting means for detecting the flow rate of the analysis gas flowing into the plasma region where the plasma is generated by the plasma generation means, the analysis means Uses the flow rate detected by the flow rate detection means to correct the concentration of the target component estimated based on the emission intensity of the wavelength component corresponding to the emission of the predetermined radical.
- the flow rate of the analysis gas flowing into the plasma region is detected by the flow rate detection means.
- the emission intensity of the plasma changes depending on the flow rate. Therefore, the concentration of the target component estimated based on the emission intensity of the wavelength component corresponding to the emission of a predetermined radical without considering the flow rate may include an error.
- the concentration of the target component estimated based on the emission intensity of the wavelength component corresponding to the emission of a predetermined radical is obtained using the flow rate detected by the flow rate detection means. It has been corrected.
- the plasma gas is provided upstream of a plasma region in which plasma is generated by the plasma generating means in the flow direction of the analysis gas.
- a shielding member for shielding a part is provided.
- a shielding member for shielding a part of the plasma region is provided upstream of the plasma region. Therefore, a change in the emission intensity of the plasma due to the influence of the flow is suppressed.
- the analyzing means analyzes plasma light extracted from a region of the plasma region that is not shielded by the shielding member, and the target component in the analysis gas is analyzed. Estimate the concentration.
- the concentration of the target component in the analysis gas is estimated by analyzing the plasma light extracted from the plasma region that is not shielded by the shielding member (hereinafter referred to as “non-shielding region”).
- non-shielding region the concentration change in the area shielded by the shielding member does not sufficiently follow the change in the bulk concentration of the flow.
- the influence of the flow is suppressed to some extent by the shielding member, and the plasma light in the non-shielding region in which the concentration change follows the change in the flow bulk concentration to some extent is used to estimate the concentration of the target component.
- a plasma generation step for bringing an analysis gas into a plasma state, and an analysis for estimating a concentration of a target component in the analysis gas by analyzing plasma light emitted from the plasma generated in the plasma generation step
- a gas concentration estimation method comprising steps.
- the analysis step of the gas concentration estimation method light emission of a wavelength component corresponding to light emission of a predetermined radical including atoms or molecules separated from the target component in the plasma light having an atomic configuration different from that of the target component. Based on the intensity, the concentration of the target component is estimated.
- the concentration of the target component of the plasma light is an atomic configuration different from that of the target component and includes a predetermined radical containing atoms or molecules separated from the target component. It is estimated based on the emission intensity of the wavelength component corresponding to the emission.
- the emission intensity of the wavelength component corresponding to the light emission of a predetermined radical containing atoms or molecules separated from the target component in an atomic configuration different from the target component is estimated. Therefore, for example, when carbon dioxide is the target component, a versatile light receiver can be used to obtain the emission intensity of the wavelength component corresponding to the emission of the CN radical, so that the versatile gas concentration estimation can be performed. Realize the device
- estimation is performed based on the emission intensity of the wavelength component corresponding to the emission of the CN radical, using the estimation result of the hydrocarbon concentration.
- the concentration of carbon dioxide is corrected. Therefore, the estimation accuracy of the concentration of carbon dioxide in the exhaust gas containing hydrocarbons can be improved.
- the object estimated based on the emission intensity of the wavelength component corresponding to the emission of the predetermined radical using the detected flow rate of the analysis gas.
- the concentration of the component is corrected. Therefore, the estimation accuracy of the concentration of the target component can be improved in a place where a flow exists.
- the shielding member for shielding a part of the plasma region is provided upstream of the plasma region, the change in the plasma emission intensity due to the influence of the flow is suppressed. Therefore, the estimation accuracy of the concentration of the target component can be improved in a place where a flow exists.
- FIG. 1 is a schematic configuration diagram of a gas concentration estimation apparatus according to an embodiment.
- Drawing 2 is a schematic structure figure of the principal part of the gas concentration estimating device of an embodiment.
- FIG. 3 is a time chart of the discharge signal and the microwave drive signal in the embodiment.
- FIG. 4 is a graph of a calibration curve representing the relationship between the emission intensity of the wavelength component corresponding to the CN radical emission and the concentration of carbon dioxide.
- FIG. 5 is a schematic configuration diagram of an optical measuring instrument (spectrometer) according to Modification 1 of the embodiment.
- FIG. 6 is a schematic configuration diagram of a main part of a gas concentration estimation apparatus according to Modification 3 of the embodiment.
- the present embodiment is a gas concentration estimation apparatus 10 that estimates the concentration of carbon dioxide using the exhaust gas of the engine 11 as an analysis gas and carbon dioxide in the analysis gas as a target component. As shown in FIGS. 1 and 2, the gas concentration estimation device 10 is attached to the exhaust pipe 12 of the engine 11. The gas concentration estimation device 10 measures the concentration of carbon dioxide in the exhaust gas flowing through the exhaust pipe 12.
- the gas concentration estimation device 10 includes a plasma generation device 15 and an analysis device 16.
- the plasma generating device 15 constitutes a plasma generating means for bringing the analysis gas into a plasma state.
- the analysis device 16 constitutes analysis means for analyzing the plasma light emitted from the plasma generated by the plasma generation device 15 and estimating the concentration of carbon dioxide in the analysis gas.
- the plasma generator 15 includes a high-pressure pulse generator 21, a microwave generator 22, a mixer 23, a discharger 24, and a control device 25.
- the control device 25 controls the high voltage pulse generator 21 and the microwave generator 22.
- the high-voltage pulse generator 21 When the high-voltage pulse generator 21 receives the discharge signal from the control device 25, the high-voltage pulse generator 21 boosts the voltage applied from a DC power supply (not shown) and generates a boosted high-voltage pulse.
- the high voltage pulse generator 21 outputs a high voltage pulse to the mixer 23.
- the high voltage pulse is an impulse voltage signal having a peak voltage of about 6 kV to 40 kV, for example.
- the microwave generator 22 When the microwave generator 22 receives a microwave drive signal from the control device 25, the microwave generator 22 generates a microwave pulse by using electric power supplied from a DC power supply (not shown). As shown in FIG. 3, the microwave generator 22 generates a microwave pulse at a predetermined duty ratio over a period from the rising edge to the falling edge of the microwave driving signal (period of the pulse width of the microwave driving signal). Output repeatedly. The microwave generator 22 repeatedly outputs the microwave pulse to the mixer 23.
- the semiconductor oscillator generates a microwave pulse, but another oscillator such as a magnetron may be used instead of the semiconductor oscillator.
- the mixer 23 receives the high voltage pulse and the microwave pulse at separate input terminals, and outputs the high voltage pulse and the microwave pulse to the discharger 24 from the same output terminal.
- the mixer 23 is configured to be able to mix a high voltage pulse and a microwave pulse.
- the discharger 24 is, for example, a spark plug 24.
- the spark plug 24 is integrated with the mixer 23.
- the spark plug 24 is attached to the exhaust pipe 12 such that a discharge gap between the center electrode 24 a and the ground electrode 24 b is located in the exhaust pipe 12.
- an input terminal electrically connected to the center electrode 24a is connected to an output terminal of the mixer 23 (not shown).
- the plasma generation device 15 performs a plasma generation operation for generating microwave plasma.
- the plasma generation operation is started when the control device 25 outputs a discharge signal and a microwave drive signal.
- the high voltage pulse generator 21 outputs a high voltage pulse when receiving a discharge signal
- the microwave generator 22 outputs a microwave pulse when receiving a microwave drive signal.
- the high voltage pulse and the microwave pulse are supplied to the center electrode 24 a of the spark plug 24 through the mixer 23.
- a spark discharge is generated in the discharge gap by the high voltage pulse. Furthermore, the microwave pulse is irradiated from the center electrode 24a to the discharge plasma generated by the spark discharge. Then, the discharge plasma expands by absorbing microwave energy, and a relatively large microwave plasma is generated. In the plasma region where the microwave plasma is formed, the exhaust gas flowing through the exhaust pipe 12 is in a plasma state.
- the center electrode 24a functions as a radiation antenna.
- the radiation antenna may be provided adjacent to the center electrode 24a. In that case, the microwave pulse is supplied to the radiating antenna by a different path from the high voltage pulse.
- the microwave drive signal is a pulse signal having a pulse width of, for example, several milliseconds.
- the microwave pulse rest period Y is too long, the microwave plasma is extinguished. Therefore, the length of the pause period Y is set so that the microwave plasma is not extinguished before the next microwave pulse is emitted.
- the microwave plasma is maintained for the time of the pulse width of the microwave drive signal (period in which the microwave pulse is repeatedly output). This period is a plasma formation period.
- the plasma generator 15 repeatedly performs a plasma generation operation with a plasma generation pause period of several milliseconds. In the discharge gap, a plasma formation state where the microwave plasma is formed and a plasma extinction state where the microwave plasma is extinguished are repeated. The plasma formation period and the plasma formation pause period are repeated in a short cycle. -Analysis equipment-
- the analyzer 16 performs an analysis operation for analyzing the plasma light of the microwave plasma generated by the plasma generation operation.
- the analyzer 16 performs an analysis operation in synchronization with a plasma generation operation that is repeated in a short cycle.
- the analyzer 16 includes an optical fiber 32, an optical measuring instrument 33, and a signal processor 34 as shown in FIGS.
- the analyzer 16 takes the plasma light of the microwave plasma into the optical measuring instrument 33 through the optical fiber 32.
- the optical measuring instrument 33 extracts a wavelength component (388 nm) corresponding to light emission of the CN radical from the plasma light, and outputs an electrical signal obtained by photoelectrically converting the extracted wavelength component.
- the signal processor 34 estimates the concentration of carbon dioxide using the electrical signal output from the optical measuring instrument 33. As shown in FIG. 2, the signal processor 34 is provided with a monitor 35 that displays the carbon dioxide concentration estimated by the signal processor 34.
- the optical fiber 32 is attached to the exhaust pipe 12 via the attachment member 31.
- the optical fiber 32 is attached so that one end surface (hereinafter referred to as “incident surface”) faces a discharge gap that becomes a plasma region.
- the other end of the optical fiber 32 is connected to the optical measuring instrument 33.
- the optical measuring instrument 33 includes an optical filter 37 and a light receiver 38.
- the optical filter 37 is disposed at a position where plasma light emitted from the emission surface of the optical fiber 32 passes.
- the optical filter 37 passes the wavelength component corresponding to the emission of the CN radical from the plasma light passing therethrough.
- the light receiver 38 is, for example, a photomultiplier tube (PMT).
- the light receiver 38 receives the light passing through the optical filter 37.
- the light receiver 38 receives a wavelength component corresponding to light emission of the CN radical.
- the light receiver 38 outputs an electric signal having a voltage value corresponding to the intensity of the received wavelength component, that is, the emission intensity of the wavelength component corresponding to the emission of the CN radical, to the signal processor 34.
- the light receiver 38 has a high time responsiveness, you may use things other than a photomultiplier tube.
- the signal processor 34 stores calibration curve data (FIG. 4) indicating the relationship between the emission intensity of the wavelength component corresponding to the emission of the CN radical and the concentration of carbon dioxide.
- the calibration curve data is a wavelength component corresponding to light emission of a CN radical while gradually changing the concentration of carbon dioxide in a gas not containing a gas component having carbon atoms other than carbon dioxide in a predetermined experimental apparatus. Is generated based on the measurement result (specifically, the voltage value of the electric signal indicating the emission intensity of the wavelength component corresponding to the emission of the CN radical).
- the concentration of carbon dioxide is associated one-to-one with the voltage value of the electric signal representing the emission intensity of the wavelength component corresponding to the emission of the CN radical.
- the signal processor 34 reads the concentration of carbon dioxide corresponding to the voltage value of the electrical signal output from the light receiver 38 in the calibration curve data.
- the signal processor 34 outputs a carbon dioxide concentration reading to the monitor 35.
- the gas concentration estimation device 10 repeatedly performs a plasma generation step and an analysis step while the engine 11 is in operation.
- the plasma generation device 15 In the plasma generation step, the plasma generation device 15 generates microwave plasma in the discharge gap and maintains it for several milliseconds.
- the exhaust gas that is the analysis gas is in a plasma state.
- the analysis device 16 analyzes the plasma light emitted from the microwave plasma generated in the plasma generation step, and estimates the concentration of carbon dioxide in the exhaust gas.
- the analysis step is performed for each plasma generation step that is repeatedly performed.
- the optical filter 37 extracts the wavelength component corresponding to the emission of the CN radical from the plasma light of the microwave plasma taken into the optical measuring instrument 33, and the light receiver 38 corresponds to the emission of the CN radical.
- An electric signal representing the emission intensity of the wavelength component is generated.
- the signal processor 34 receives an electric signal representing the emission intensity of the wavelength component corresponding to the emission of the CN radical.
- the concentration of carbon dioxide corresponding to the voltage value of the electrical signal is read from the calibration curve data.
- an analysis step is performed for each plasma generation step, and the concentration of carbon dioxide is estimated in a short cycle. As a result, time series data with high temporal resolution of the concentration of carbon dioxide is created.
- the analyzer 16 estimates the concentration of unburned hydrocarbons in the exhaust gas, and uses the estimation result to estimate the carbon dioxide estimated based on the emission intensity of the wavelength component corresponding to the emission of the CN radical. Is corrected (concentration of carbon dioxide read from the calibration curve data in FIG. 4).
- the optical measuring instrument 33 is configured by a spectroscope 33 that splits plasma light taken in via an optical fiber 32, as shown in FIG.
- the optical measuring instrument 33 photoelectrically converts a wavelength component corresponding to light emission of CH radicals, and a first measurement unit 33a that outputs a first electric signal obtained by photoelectrically converting wavelength components corresponding to light emission of CN radicals in plasma light.
- a second measuring unit 33b for outputting the second electric signal.
- Each measurement unit 33a, 33b includes dichroic mirrors 39a, 39b, optical filters 37a, 37b, and light receivers 38a, 38b.
- the dichroic mirrors 39a and 39b separate plasma light.
- the optical filters 37a and 37b function as interference filters.
- Each of the light receivers 38a and 38b is a photomultiplier tube as in the embodiment.
- the signal processor 34 includes calibration curve data (hereinafter referred to as “second data”) for estimating the concentration of carbon hydrogen.
- the second data shows the relationship between the emission intensity of the wavelength component corresponding to the emission of the CH radical and the concentration of carbon hydrogen.
- the second data is the emission of the wavelength component corresponding to the emission of the CH radical while the concentration of carbon hydrogen is changed little by little in a gas not containing gas molecules having carbon atoms other than carbon hydrogen in a predetermined experimental apparatus. It is created based on the result of estimating the intensity.
- the hydrocarbon concentration is associated one-to-one with the voltage value of the electrical signal representing the emission intensity of the wavelength component corresponding to the CH radical emission.
- the signal processor 34 reads the concentration of carbon dioxide corresponding to the voltage value of the first electric signal (hereinafter referred to as “first reading concentration”) from the first data. Further, the signal processor 34 reads a hydrocarbon concentration corresponding to the voltage value of the second electric signal (hereinafter referred to as “second reading concentration”) from the second data. The signal processor 34 does not set the first reading density as the final estimated value of the carbon dioxide concentration, but, for example, obtains a value obtained by subtracting the second reading density from the first reading density as the final estimated value of the carbon dioxide density. Output as.
- the gas concentration estimation device 10 estimates the concentration of water vapor using the water vapor in the analysis gas as a target component.
- the optical measuring instrument 33 extracts a wavelength component corresponding to OH radical emission from the plasma light of the microwave plasma, and outputs an electrical signal obtained by photoelectrically converting the extracted wavelength component.
- the voltage value of this electric signal represents the emission intensity of the wavelength component corresponding to the emission of the OH radical.
- the signal processor 34 estimates the water vapor concentration using the electrical signal output from the optical measuring device 33. At this time, the concentration of water vapor is estimated using calibration curve data indicating the relationship between the emission intensity of the wavelength component corresponding to the emission of OH radicals and the concentration of water vapor. The signal processor 34 estimates the water vapor concentration based on the emission intensity of the wavelength component corresponding to the emission of the OH radical.
- a shielding member 50 that shields a part of the plasma region 51 is provided upstream of the plasma region 51 where the microwave plasma 51 is generated by the plasma generator 15.
- the shielding member 50 is a plate-like conductive member protruding from the inner surface of the exhaust pipe 12.
- the shielding member 50 is provided adjacent to the tip of the spark plug 24.
- the shielding member 50 is provided with a ground electrode 24 b of the spark plug 24. The ground electrode 24 b is grounded via the shielding member 50.
- a plate-like member 52 having the same shape as the shielding member 50 is also provided downstream of the spark plug. By providing the plate-like member 52, the flow between the shielding member 50 and the plate-like member 52 is stabilized.
- the microwave plasma 51 is generated in a region between the center electrode 24a on the side of the center electrode 24a and the ground electrode 24b. A part of the microwave plasma 51 protrudes from the tip of the shielding member 50 toward the central axis of the exhaust pipe 12.
- the analysis device 16 analyzes the plasma light extracted from the non-shielding region that is not shielded by the shielding member 50 in the plasma region 51, and estimates the concentration of the target component in the analysis gas.
- a condensing optical system having a focal point in the non-shielding region is provided on the exhaust pipe 12 side of the optical fiber 32 to extract plasma light in the non-shielding region.
- the influence of the flow is suppressed to some extent by the shielding member 50, and the plasma light in the non-shielding region in which the concentration change follows the change in the bulk concentration of the flow to some extent is used to estimate the concentration of the target component.
- the shielding member 50 may have an inclined surface on the upstream side. In this case, the shielding member 50 becomes thicker as the width approaches the exhaust pipe 12.
- the analysis device 16 uses the flow rate of the analysis gas flowing into the plasma region where the plasma is generated by the plasma generation device 15, and estimates it based on the emission intensity of the wavelength component corresponding to the emission of the CN radical. Correct the carbon concentration.
- the flow rate of the analysis gas is detected by a flow rate detection device (flow rate detection means) disposed upstream of the ignition plug 24 in the exhaust pipe 12.
- a plurality of calibration curve data is created according to the flow rate of the analysis gas flowing into the plasma region, and the calibration curve data to be used is selected according to the detection result of the flow rate detection device. Good. ⁇ Other Embodiments >>
- the embodiment may be configured as follows.
- the plasma generation device 15 may generate plasma by condensing laser light. Further, the plasma generator 15 may generate microwave plasma by supplying microwave energy to plasma generated by condensing laser light. In these cases, the concentration of carbon dioxide is estimated based on the emission intensity of the wavelength component corresponding to the emission of the CN radical by the laser-induced fluorescence method.
- the plasma generator 15 may generate microwave plasma by supplying microwave energy to the thermoelectrons emitted from a thermionic emitter such as a glow plug.
- the analysis gas may be in a plasma state using plasma that does not use microwaves.
- the exhaust gas is used as the analysis gas, but other gases (for example, human exhalation) may be used as the analysis gas.
- the present invention is useful for a gas concentration estimation apparatus and a gas concentration estimation method for estimating the concentration of a target component in an analysis gas by analyzing light emitted from the plasma of the analysis gas.
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Abstract
Description
-プラズマ生成装置-
-分析装置-
-ガス濃度推定装置の動作-
-実施形態の効果-
-実施形態の変形例1-
-実施形態の変形例2-
-実施形態の変形例3-
-実施形態の変形例4-
《その他の実施形態》
11 エンジン
12 排気管
15 プラズマ生成装置(プラズマ生成手段)
16 分析装置(分析手段)
23 混合器
24 放電器
32 光ファイバー
Claims (10)
- 分析ガスをプラズマ状態にするプラズマ生成手段と、
前記プラズマ生成手段により生成されたプラズマから発せられるプラズマ光を分析して、前記分析ガス中の対象成分の濃度を推定する分析手段とを備えたガス濃度推定装置であって、
前記分析手段は、前記プラズマ光のうち、前記対象成分とは異なる原子構成で、該対象成分から分離した原子又は分子を含む所定のラジカルの発光に対応する波長成分の発光強度に基づいて、前記対象成分の濃度を推定する
ことを特徴とするガス濃度推定装置。 - 請求項1において、
前記分析手段は、前記プラズマ光のうち、CNラジカルの発光に対応する波長成分の発光強度に基づいて、前記対象成分としての二酸化炭素の濃度を推定する
ことを特徴とするガス濃度推定装置。 - 請求項2において、
炭化水素の燃焼後に排出される排気ガスを前記分析ガスとして、該分析ガス中の二酸化炭素を前記対象成分とする一方、
前記分析手段は、前記排気ガス中の未燃の炭化水素の濃度を推定し、その推定結果を用いて、CNラジカルの発光に対応する波長成分の発光強度に基づき推定した二酸化炭素の濃度を補正する
ことを特徴とするガス濃度推定装置。 - 請求項3において、
前記分析手段は、前記プラズマの発光のうち、CHラジカルの発光に対応する波長成分の発光強度に基づいて、未燃の炭化水素の濃度を推定する
ことを特徴とするガス濃度推定装置。 - 請求項2乃至4の何れか1つにおいて、
前記分析手段は、CNラジカルの発光に対応する波長成分の発光強度と二酸化炭素の濃度との関係を表す検量線を用いて、前記CNラジカルの発光に対応する波長成分の発光強度から二酸化炭素の濃度を推定する
ことを特徴とするガス濃度推定装置。 - 請求項1において、
前記分析手段は、前記プラズマの発光のうち、OHラジカルの発光に対応する波長成分の発光強度に基づいて、前記対象成分としての水蒸気の濃度を推定する
ことを特徴とするガス濃度推定装置。 - 請求項1乃至6の何れか1つにおいて、
前記プラズマ生成手段によりプラズマが生成されるプラズマ領域に流入する分析ガスの流量を検出する流量検出手段を備え、
前記分析手段は、前記流量検出手段により検出された流量を用いて、前記所定のラジカルの発光に対応する波長成分の発光強度に基づき推定した前記対象成分の濃度を補正する
ことを特徴とするガス濃度推定装置。 - 請求項1乃至7の何れか1つにおいて、
前記分析ガスの流通方向において、前記プラズマ生成手段によりプラズマが生成されるプラズマ領域の上流に設けられ、該プラズマ領域の一部を遮蔽する遮蔽部材を備えている
ことを特徴とするガス濃度推定装置。 - 請求項8において、
前記分析手段は、前記プラズマ領域のうち、前記遮蔽部材により遮蔽されていない領域から抽出したプラズマ光を分析して、前記分析ガス中の対象成分の濃度を推定する
ことを特徴とするガス濃度推定装置。 - 分析ガスをプラズマ状態にするプラズマ生成ステップと、
前記プラズマ生成ステップにおいて生成されたプラズマから発せられるプラズマ光を分析して、前記分析ガス中の対象成分の濃度を推定する分析ステップとを備えたガス濃度推定方法であって、
前記分析ステップでは、前記プラズマ光のうち、前記対象成分とは異なる原子構成で、該対象成分から分離した原子又は分子を含む所定のラジカルの発光に対応する波長成分の発光強度に基づいて、前記対象成分の濃度が推定される
ことを特徴とするガス濃度推定方法。
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EP12863370.8A EP2799846A4 (en) | 2011-12-28 | 2012-12-26 | DEVICE FOR ESTIMATING A GAS CONCENTRATION |
JP2013551726A JP6233639B2 (ja) | 2011-12-28 | 2012-12-26 | ガス濃度推定装置 |
US14/369,020 US10078053B2 (en) | 2011-12-28 | 2012-12-26 | Gas concentration estimation device |
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GB2583897A (en) | 2019-04-05 | 2020-11-18 | Servomex Group Ltd | Glow plasma stabilisation |
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