[go: up one dir, main page]

WO2003019160A2 - Structure a chemin optique pour detection d'emissions dans un chemin ouvert - Google Patents

Structure a chemin optique pour detection d'emissions dans un chemin ouvert Download PDF

Info

Publication number
WO2003019160A2
WO2003019160A2 PCT/US2002/025173 US0225173W WO03019160A2 WO 2003019160 A2 WO2003019160 A2 WO 2003019160A2 US 0225173 W US0225173 W US 0225173W WO 03019160 A2 WO03019160 A2 WO 03019160A2
Authority
WO
WIPO (PCT)
Prior art keywords
light
emitter
path
emitting
infrared
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2002/025173
Other languages
English (en)
Other versions
WO2003019160A3 (fr
Inventor
Craig S. Rendahl
John Didomenico
Robert A. Gentala
Theresa A. Foley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SPX Technologies Inc
Original Assignee
SPX Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/934,272 external-priority patent/US6744516B2/en
Application filed by SPX Corp filed Critical SPX Corp
Priority to AU2002331016A priority Critical patent/AU2002331016A1/en
Publication of WO2003019160A2 publication Critical patent/WO2003019160A2/fr
Publication of WO2003019160A3 publication Critical patent/WO2003019160A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
    • G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
    • G01N21/534—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke by measuring transmission alone, i.e. determining opacity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M15/00—Testing of engines
    • G01M15/04—Testing internal-combustion engines
    • G01M15/10—Testing internal-combustion engines by monitoring exhaust gases or combustion flame
    • G01M15/102—Testing internal-combustion engines by monitoring exhaust gases or combustion flame by monitoring exhaust gases
    • G01M15/108—Testing internal-combustion engines by monitoring exhaust gases or combustion flame by monitoring exhaust gases using optical methods
    • 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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
    • 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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • 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
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G01N15/075—Investigating concentration of particle suspensions by optical means
    • 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
    • G01N2001/2264—Sampling from a flowing stream of gas with dilution
    • 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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
    • G01N2021/3155—Measuring in two spectral ranges, e.g. UV and visible
    • 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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
    • G01N2021/317—Special constructive features
    • G01N2021/3174—Filter wheel
    • 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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • G01N2021/3513—Open path with an instrumental source
    • 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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • G01N21/3518—Devices using gas filter correlation techniques; Devices using gas pressure modulation techniques
    • G01N2021/3527—Devices using gas filter correlation techniques; Devices using gas pressure modulation techniques and using one filter cell as attenuator

Definitions

  • the present invention relates generally to remote sensing systems. More particularly, the present invention relates to an apparatus for transmitting, reflecting, and detecting light in an open path sensing system such as a vehicle emission sensing system, having use in detecting and/or measuring one or more components of the air through which the light passes.
  • an open path sensing system such as a vehicle emission sensing system
  • Open path vehicle emission systems are often preferable to closed path systems because they can be used in numerous locations and do not require the vehicle to stop for testing.
  • Various open path emission sensing systems have been known.
  • One such device uses a radiation source on one side of a roadway that projects a beam across the roadway to be received by a detector.
  • the radiation source and the detector are located on opposite sides of the roadway.
  • the radiation source emits light spectra that may be used to detect an emission signature by way of absorption of light, or which alternatively may be used to excite emission components so as to cause the components to emit light.
  • the detected emission signature can then be used in various applications, such as the measurement of a vehicle's compliance with emission limits and the determination of the type of fuel that a vehicle is using.
  • a disadvantage of many known arrangements is that the radiation sources and detectors must be placed on opposite sides of the roadway from each other. Since both the detectors and radiation sources require power to operate, this means that a separate power supply must be provided on each side of the roadway.
  • Some known arrangements have tried to overcome this problem by using a radiation source on one side of a roadway and a reflective apparatus on the other side of the roadway.
  • current open path embodiments are unable to measure particulate matter (PM), as they are equipped to only measure the density, referred to as "opacity", of smoke emanating from a vehicle's exhaust.
  • PM particulate matter
  • Opacity the density
  • a device for measuring particulate matter includes a light source that emits light, a receiver positioned to receive light emitted from the light source, and a detection unit in communication with the receiver.
  • the detection unit detects an amount of particulate matter based upon the light received by the receiver.
  • a method for determining a concentration of particulate matter includes the steps of emitting light from a light source, receiving the light emitted from the light source in a receiver, and determining an amount of particulate matter using the light received in the receiver.
  • a system for measuring particulate matter includes a light source means for emitting light and a receiver means for receiving the light emitted from the light source means.
  • the receiver means is positioned to receive the light emitted from the light source means.
  • the system further includes a detection unit means for determining an amount of particulate matter based upon the light received by the receiver.
  • the detection unit means is in communication with the receiver means.
  • FIG. 1 illustrates a preferred embodiment of a source unit of the present invention including housing with window, light sources, filter wheel, beam splitter/combiner, and reflector.
  • FIG. 2 illustrates a preferred embodiment of a reflection unit of the present invention.
  • FIG. 3 illustrates a preferred embodiment of a detection unit of the present invention including housing with window, reflector, beam splitter/combiner, detector and spectrometers.
  • FIG. 4 illustrates an exemplary filter wheel that may be used in accordance with one embodiment of the present invention.
  • FIG. 5 illustrates an alternate embodiment of a detection unit of the present invention including housing with window, reflector, beam splitter/combiners, spectrometers, spinning reflector, monolithic ellipsoidal mirror, filter array with gas cells, focusing reflector, and a single infrared detector.
  • FIG. 6 illustrates several elements of an exemplary computer of a type suitable for carrying out certain functions of the present invention.
  • FIG. 7 illustrates a detection unit using multiple spectrometers and a single detector.
  • FIG. 8 illustrates the properties of an ellipsoidal reflector.
  • FIG. 9 is a conceptual diagram of some basic components of the present invention, including light source, reflection unit, detection unit, and processor.
  • FIG. 10 illustrates the addition of reflectors to the components of FIG. 9.
  • FIG. 11 illustrates the properties of a paraboloidal reflector.
  • FIG. 12 further illustrates the properties of a paraboloidal reflector.
  • FIG. 13 illustrates the addition of multiple light sources with beam splitter/combiners to the components of FIG. 10.
  • FIG. 14 illustrates a modification of the embodiment shown in
  • FIG. 13 illustrating the arrangement of opposed sources.
  • infrared, visible, and ultraviolet radiation is combined into one beam, directed across a path such as a road along which vehicles travel and generate exhaust, reflected back across the path, collected and concentrated, separated again, and received by one or more discrete detectors and/or spectrometers.
  • the infrared light passes through a sequence of filters and/or gas cells either before or after traversing the path of light across the road.
  • the filters are preferably narrow band pass filters and the gas cells contain known concentrations of gases of interest, such that each filter or combination of filters and gas cells is specific to a gas of interest.
  • a spinning wheel holds the filters and passes each filter in front of the infrared light source in sequence, before the light traverses the road.
  • the infrared light after traversing the road, is distributed by a spinning reflector, such as a mirror, into a stationary array of filters and/or gas cells in sequence to an ellipsoidal mirror or an array of ellipsoidal mirrors that focus the light into a single detector.
  • the visible and ultraviolet light is directed to one or more spectrometers that can analyze the desired wavelength ranges directly.
  • FIG. 1 illustrates a possible light source component of the present invention.
  • the light source component shown includes an infrared light source 10, a source of visible light 11, and an ultraviolet light source 12.
  • the infrared light 14 emitted by the infrared source 10 passes through a filter wheel 16, more completely described in FIG. 4.
  • the reflector 26 reflects the infrared light along a path 22, through a protective window 25 in the housing 27, leading to a reflection unit illustrated in FIG. 2.
  • the neutral density filter 18 may also optionally be omitted with the infrared light source 10 taking the position of the ultraviolet source 12 in such an alternative arrangement.
  • These windows are preferably made of a material such as calcium fluoride (CaF 2 ), sapphire, or other material that will pass light of all wavelengths of interest with little or no attenuation.
  • the windows may be coated by a particular type of coating such as an anti-reflection coating or other suitable coating to enhance the transmission of light of the wavelengths of interest.
  • the infrared light source 10 may be any source that emits a sufficient intensity of light of the wavelengths of interest.
  • the reflectors and optical path length determine the size of the spot from the infrared source that contributes to the light beam.
  • the source is chosen, such that the light emitting area of the filament is as close to that spot size as possible for minimum power consumption.
  • the filter wheel 16 is a spinning wheel that is powered by a motor 15 that spins the wheel 16 about an axis 19.
  • a synchronization device 58 is provided to track the position and rotational speed of the filter wheel 16.
  • Features of the filter wheel 16 are more completely illustrated in FIG. 4.
  • visible light from source 11 is focused by an optical element 13 to bring diverging light rays back into a focus through the center of ultraviolet source 12 where it is combined with the ultraviolet light from source 12 into a combined beam 24.
  • the combined visible and ultraviolet light 24 passes through the beam splitter/combiner 18 such that it also follows optical path 20 to the reflector 26, where the light is reflected to also follow path 22 out window 25 toward the reflection unit illustrated in FIG. 2.
  • the visible light source 11 may be a light emitting diode (LED), which emits light in a narrow range of wavelengths, or another visible source such as a halogen lamp that emits a broader range of wavelengths.
  • the visible light source 11 is not required for gaseous measurements, however visible light is used to measure particulate matter and potentially opacity and lubricating oil elements.
  • Particulate Matter having a diameter of 2.5 microns and smaller can be measured by an absorption technique at a wavelength of 500 nanometers, using a spectrometer such as in FIG.3, element 42.
  • a PM 2 5 measurement would best be taken at 530 nanometers, however when measuring vehicle exhaust, there are interferences caused by gaseous species such as nitrogen dioxide (NO 2 ) that also absorb at
  • This same PM 5 information can be used to determine whether a gasoline-powered vehicle is in a cold start mode.
  • Cold start is when the engine of the vehicle being tested is not up to its normal operating temperature.
  • a gasoline-powered vehicle in cold start mode will emit a much greater amount of particulates, on par with the amount of particulate emissions from diesel-powered vehicles, than a vehicle up to normal operating temperature.
  • Cold start information is very useful for open-path emissions testing equipment, as it is important when enforcing air pollution laws not to falsely incriminate a tested vehicle for excess emissions when the vehicle is merely not operating in a normal mode.
  • the ultraviolet light source 12 is preferably an ultraviolet lamp such as deuterium lamp, a xenon lamp, or another lamp that has ultraviolet light emission characteristics broad enough to include wavelengths of interest, ideally to emit light for at least all of the ultraviolet wavelengths of interest as listed in Table 1.
  • an ultraviolet lamp such as deuterium lamp, a xenon lamp, or another lamp that has ultraviolet light emission characteristics broad enough to include wavelengths of interest, ideally to emit light for at least all of the ultraviolet wavelengths of interest as listed in Table 1.
  • FIG. 1 illustrates, where multiple light sources such as components 10, 11, and 12 are provided, the emitted beams preferably follow substantially the same optical path 20 toward the reflector 26.
  • the reflector 26 is positioned such that light sources 10, 11, and 12 are near the focal point of the reflector 26 and the reflected light 22 is parallel to its axis of rotation.
  • the angle between the incoming 20 and reflected light 22 and the focal length are determined by the design of the reflector 26 and may be chosen based on considerations of component layout and F-number. (F-number of an off-axis paraboloidal mirror is defined as the diameter of the mirror divided by its effective focal length.)
  • F-number of an off-axis paraboloidal mirror is defined as the diameter of the mirror divided by its effective focal length.
  • beam splitter/combiner 18 is a neutral density filter, it is preferably chosen so that the proportion of visible and ultraviolet light passed and the proportion of infrared light reflected are balanced according to the requirements of the detection unit.
  • a beam splitter/combiner 18 that is sensitive to different wavelengths such as a dichroic beam splitter may be used instead of a neutral density filter for beam splitter/combiner 18.
  • the positions of the infrared 10 and visible/ultraviolet sources 11, 12 may be reversed.
  • the focal point is such that the light reflected away from the reflector 26 and the incoming light form an angle of approximately 30 degrees.
  • the neutral density filter component 18 preferably is designed so that it substantially reflects ultraviolet but substantially passes infrared light, although 100% reflection/detection of such light components is not required.
  • the off-axis reflector is protected by a calcium fluoride (CaF 2 ) window or cover.
  • the infrared light source item 10 preferably is a low power consumption (preferably less than about ten watts) integrating sphere comprised of a filament positioned around a central member.
  • the filament and member when energized, emit light, and the sphere, with most or all of its internal surface comprised of reflective material, concentrates the light to exit through an opening in the sphere, thus creating a pure source of infrared light.
  • the light source has little or no cool spots from filament or other material that would interfere with a homogenous transmittance of light.
  • other light sources such as pure bulbs or filaments, may be used.
  • the visible light source 11 is preferably a light emitting diode
  • the ultraviolet light source 12 is preferably an ultraviolet lamp such as deuterium lamp, a xenon lamp, or another lamp that provides ultraviolet light in spectra of interest.
  • the visible light source 11 is focused through an orifice in the ultraviolet lamp, combining the visible and ultraviolet light (UV/NIS).
  • the filter/mirror 18 preferably is a neutral density filter positioned at an angle to the axis of the beam of UN/VIS light.
  • the neutral density filter 18 acts as a beam combiner, reflecting the light from the infrared source 10 and allowing the UV/NIS light to pass through.
  • the off- axis reflector 26 then collimates the combined light and directs it across the path 22.
  • the beam splitter/combiner 18 may also optionally be omitted, with the infrared light source 10, filter wheel 16, and associated components, taking the position of the ultraviolet source 12 in such an alternative arrangement.
  • This option of the preferred embodiment may be desired for more economical utilizations of this embodiment where not all exhaust emissions constituents are desired to be measured, or a preference exists to simplify the production of such an embodiment with the potential compromise of poorer data quality
  • FIG. 2 illustrates an exemplary reflection unit, which in an embodiment used to detect vehicle emissions is preferably placed across the road from the light source and detector components, creating an open-path emissions testing system.
  • the reflection unit includes a retro-reflective system, preferably a vertical system, and preferably comprising three mirrors positioned to form 90° angles with respect to each other. A vertical orientation of the mirror assembly is preferred in order to adequately capture the emissions of vehicles of all profiles and heights.
  • incoming light 22 is reflected by a first mirror 30 and a second mirror 32.
  • the first and second mirrors are adjacent or substantially adjacent to each other to form a 90° angle.
  • the light reflected by the first and second mirrors is transmitted to a third mirror 34.
  • FIG. 1 illustrates an exemplary reflection unit, which in an embodiment used to detect vehicle emissions is preferably placed across the road from the light source and detector components, creating an open-path emissions testing system.
  • the reflection unit includes a retro-reflective system, preferably a vertical system, and preferably comprising three
  • third mirror 34 forms a 90° angle with the flat reflective portions of both first mirror 30 and second mirror 32. It is not important to have mirrors 30,32 on top of mirror 34, as this orientation could be reversed without any change to the quality of reflection of light.
  • Light 36 that is reflected by third mirror 34 is then transmitted to the detection unit and travels in a direction that is parallel to the incoming light 22 in a configuration as illustrated in FIG. 9 to be discussed later in this text.
  • the incoming light 22 and/or the reflected light 36 pass through an air component that is to be measured, such as vehicle emissions.
  • the infrared detector 50 is positioned within the focal volume so that the light will over-bathe the detector's active area so that system vibrations will not adversely affecting measurements by causing a portion of the detector's active surface to temporarily not have light exposure.
  • Focal volume is defined as the three-dimensional volume of light, in which the light is focused to its maximum intensity, in this instance infrared light 48, that travels to the detector 50. Maximum intensity of light occurs when all lights rays are concentrated into the smallest cross-sectional area of the focal volume. This cross-sectional area is not necessarily located at the focal point of the reflector 38, but is located farther away from the reflector 38 than the focal point.
  • spectrometers 42, 43 are commercially available for most ranges of wavelengths of interest in the visible and ultraviolet regions. In the infrared region, however, spectrometers are less practical than individual detectors optimized for particular ranges of wavelengths. These infrared detectors are expensive and require cooling and complicated electronics for support. It is therefore a great advantage to use only a single infrared detector 50 in the detection unit. If separate detectors are used to detect the intensity of each wavelength or band of wavelengths of interest, the calibration problem caused by the different sensitivities of the different detectors must be addressed. This problem is further compounded because sensitivities change with time and temperature and can be different for each detector.
  • the infrared detector 50 is preferably composed of mercury- cadmium-telluride (MCT), preferably utilizing at least three-stage thermal electric cooling.
  • MCT mercury- cadmium-telluride
  • a lead-selenide or other composition detector can be used, and with greater or lesser staged cooling.
  • a liquid cooled detector could also be utilized in this embodiment provided there is supporting equipment to accommodate the liquid cooling.
  • Another possibility for cooling the detector is by Stirling Engine cooling, however this adds cost and complexity.
  • the MCT composition detectors offer a more compatible electronic biasing consistent with reduced noise than other composition detectors.
  • Other factors considered for single detector selection is the detectivity, commonly expressed in terms of "D*", responsivity to light, the timing of the pulses of light to which the detector is exposed, and the saturation level.
  • This embodiment also prefers the economy of a photoconductive type of single detector as opposed to the more expensive photovoltaic detector. While photovoltaic detectors comparably offer less noise in lower pulse frequencies, this is not an issue for this embodiment as it is desirable to stimulate the detector with as high a frequency that the spinning filter wheel illustrated in FIG. 1 item 16, or spinning reflector illustrated in
  • a dual substrate detector may be used.
  • a commercially available dual substrate detector contains two different semiconductor compounds, each sensitive to slightly different ranges of wavelengths. They are mounted in a single detector package, one in front of the other so that their active areas nearly coincide. Thus the combination performs as if it were a single detector with sensitivity to a broader range of wavelengths than would otherwise be possible.
  • the first is to focus light onto the end of a Y-shaped optical fiber cable 41 that first receives the light in a single open end of the fiber optic cable, then divides the light within the cable sending a portion of the light to each spectrometer.
  • An alternative method of splitting the light to two or more spectrometers is to use separate beam splitter/combiners 44 and 162 to split light beam 40 twice.
  • Beam splitter/combiner 44 first splits beam 40 into beams 170 and 172. Beam 170 is focused directly into the opening of spectrometer 43 while beam 172 continues on to beam splitter/combiner 162.
  • Beam splitter/combiner 162 then splits beam 172 into beams 174 and 176.
  • Each filter 52 is designed to allow light of a specific range of wavelengths to pass through it.
  • the filter wheel preferably will have one or more synchronization marks 56 that may be detected by a synchronization unit 58 to define either the exact filter or the start of a sequence of filters that will be in the optical path.
  • the wheel 16 must have an opaque area 60 between each filter.
  • the opaque areas 60 prohibit source light (FIG. 1 item 10) from getting to a detector when the opaque areas 60 pass in front of the infrared source (FIG.l item 10) transforming the incident light beam into a sequence of pulses (FIG. 1 item 17).
  • the wheel spins about an axis 19 at high speeds, preferably at least 12,000 rotations per minute, to form a sequence of infrared light pulses (FIG. 1 item 17).
  • the single infrared detector sees a sequence of pulses of light 76 that are essentially the same as those illustrated as FIG. 3 item 48.
  • Each filter 52,53,54 of this array substantially limits the passage of light to a predetermined spectral wavelength or range of wavelengths. Some filter center wave specifications are listed in Table 1.
  • Each gas cell 70 of this array substantially limits the passage of light of a particular spectral pattern of wavelengths absorbed by the known concentration of the gas of interest that the cell 70 contains.
  • Another advantage of this embodiment is that there is much less rotating mass in the spinning reflector 62 than in the spinning filter wheel illustrated in FIG. 4. Therefore the spinning reflector 62 can be spun at a much faster rate than the spinning filter wheel illustrated in FIG. 4. Faster spin rate corresponds to a higher sampling rate that can contribute to lower electronic and optical noise levels, and provide better time resolution of a plume of vehicle exhaust constituents.
  • an ellipsoidal mirror is the best choice for this alternative embodiment.
  • An alternative embodiment replaces the monolithic ellipsoidal mirror 80 with individual ellipsoidal mirrors and may place the filters 52,53,54 and gas cell 70 array before the individual ellipsoidal mirrors if layout and construction is simplified.
  • This alternative can provide the advantage of the system suffering less light loss through use of individual mirrors as opposed to the monolithic ellipsoidal mirror 80.
  • the disadvantage is that there may be more adjustments required in order to have the system of FIG. 5 properly aligned such that all light through the system is optimized.
  • the system illustrated in FIG. 6 also includes a memory 104 which may be a memory device such as a hard drive, random access memory, or read only memory. A portion of this memory 104 can contain the instructions for the processor 92 to carry out the tasks associated with the measurement of vehicular emissions.
  • concentrations of gases may be derived using the Beer-Lambert Law, however other tests and formulae may be used in alternate embodiments.
  • Equation 1 Beer-Lambert Law
  • %T is the amount of light transmitted through open air and the emissions sample expressed in percent units
  • e is the absorption coefficient for the gas of interest at a corresponding wavelength of absorption
  • C is the concentration of the gas of interest expressed in parts-per- million (ppm) / is the path length expressed in meters.
  • I p is amount of light left after passing through the gas sample of interest
  • Equation 3 is an algebraic substitution of transmittance "%T" (Equation 2), and subsequent manipulation of Beer- Lambert Law of Equation 1 to solve for a concentration of a gas in an open path, as this is the unknown for which this embodiment measures. Equation 3: Application of Beer-Lambert in this Embodiment
  • Equation 3 The concentrations calculated in Equation 3 are expressed in units of parts per million (ppm) for gaseous measurements, or micromoles/mole for particulate measurements.
  • the correlation coefficient is empirically derived per acceptable methods of empirical establishment of a correlation coefficient for each gas of interest and PM 2 5 absorption.
  • Equation 4 illustrates the conversion needed to go from a measurement in units of micromoles/mole to micrograms per cubic meter ( ⁇ g/M3) at Standard Temperature and Pressure (STP), the standard units for a typical PM 2 . 5 measurement.
  • STP Standard Temperature and Pressure
  • Temperature measurements of the measurement path are read or converted in the preferred embodiment to degrees Kelvin (°K) or other suitable temperature scale which has a lower limit at absolute zero.
  • Other memory devices 106 and 108 such as additional hard disk storage, a CD-ROM, CD-RW, DND, floppy drive, ZIP® drive, compact flash compatible device such as that which conforms to IBM MicrodriveTM specification, or other memory device may also be included.
  • An internal memory device 106 can be used to extend the number of emissions tests that can be conducted and retained by this preferred embodiment.
  • a removable memory device 108 can be used to make the emissions data portable to allow for the emissions data to be further processed in a centralized location.
  • the device also optionally and preferably includes a display 110 and/or a transmitter 112 for providing output to a user or another device.
  • the intensity measured by the detector unit 90 at a wavelength of interest is compared by the processor 92 to the intensity of light detected by the detector unit 90 at a reference wavelength where no absorption of gases occurs.
  • This method of detection is commonly known as Differential Optical Absorption Spectroscopy (DOAS).
  • DOAS Differential Optical Absorption Spectroscopy
  • the intensity measured by a detector unit 90 at a desired wavelength for an interval of time, followed by measuring light at the detector unit 90 for an interval of time at the same desired wavelength with additionally a gas cell of known concentration of gas that absorbs light of the same wavelength can also be used as a methodology to determine a concentration of a gas of interest.
  • This method of detection is commonly known as Gas Filter Correlation Radiometry (GFCr), and is documented in other art. GFCr has the potential to provide improved precision & accuracy of measurements due to the fact that the methodology allows for the constant referencing of a measurement to a known concentration of the gas of interest.
  • FIG. 5 shows both DOAS and GFCr methods of determining a concentration of a gas of interest contained within the same embodiment.
  • an optical filter 53 can be optimized for sampling carbon dioxide (CO 2 ).
  • Another filter 54 can be optimized to pass wavelengths of light where no absorption of CO 2 or other gases exist; such a filter is used for reference to assess the amount of light that passes through the sample path without CO 2 influence. As the amount of CO 2 concentration increases, the amount of light that the detector 50 observes through filter 53 will decrease, while the amount of light that the detector 50 observes through the reference filter 54 will remain unchanged.
  • a CO 2 filter 53 can be paired with another similar characteristic CO 2 filter 52 with the difference that the CO 2 filter 52 has a windowed small cell 70 that contains a sample of CO 2 gas.
  • the amount of gas in the cell 70 is chosen based on the amount of optical depth that is desired with which the non-celled optical path is compared.
  • the CO 2 filter 53 must have balancing windows 78 of the same optical characteristics as the gas cell 70 in order to make the amount of light between both light paths roughly equivalent.
  • the memory 104 can contain combustion equations unique to different fuels used to power vehicles that are tested by this preferred embodiment. Determination of the type of fuel used to power a tested vehicle can be done in the processor 92 at the time of measurement of the tailpipe emissions, or after emissions testing activities have concluded at the monitoring site in a centralized data processing facility.
  • a method for determining the type of fuel of a vehicle is disclosed in U.S. Patent application serial number 09/928,720 entitled "METHOD AND SYSTEM FOR DETERMINING THE TYPE OF FUEL USED TO POWER A VEHICLE", filed August 13, 2001, the disclosure of which is hereby incorporated by reference in its entirety.
  • the system also includes a first reflector 130 positioned to receive the beam 128 from the light source 120 and reflect the beam 132 toward the reflection unit 124.
  • the reflection unit 124 is positioned to receive the beam 132 from the first reflector 130 and reflect the beam 134 toward a second reflector 136.
  • the second reflector 136 is positioned to receive the beam 134 reflected by the refection unit 124 and reflect the beam 138 toward the detection unit 90.
  • each reflector 130,136 comprises an off-axis paraboloidal mirror, however a spherical or other similar mirror could be used.
  • a paraboloidal mirror 180 has the property that light rays 182 emitted from and diverging from a small spot of a light source 184 placed near the paraboloidal mirror 180 focus 186 are reflected into a beam of rays 188 nearly parallel to the axis of rotation 190 of the mirror.
  • a beam of light rays 192 traveling nearly parallel to the axis of rotation 190 of a paraboloidal mirror 180 become rays 194 reflected toward and concentrated into a small spot near the paraboloidal mirror focus 186.
  • a beam of light travels along an optical path 128, 132, 134, and 138 from the light source 120, to the first reflector
  • light 212 from an ultraviolet source 12 is traveling in the opposite direction from the light 14 emanating from the infrared source 10, the ultraviolet light 212 is naturally kept away from the infrared detector 50 without the use of additional wavelength dependent filters or beam splitter/combiners.
  • Light sources 12,10 and detectors 43, 50 need to be matched with optical components of corresponding F-numbers for efficient light transmission.
  • An embodiment using opposed sources, and first and second reflectors 130,136 of significantly different F-number allows the sources or detectors requiring a higher F-number to be matched with the reflector with the higher F-number, and the sources and detectors requiring a lower F-number to be matched with the reflector with the lower F-number. This eliminates the need for additional optical components for F-number matching.
  • opposed sources may significantly simplify component layout and reduction of thermal and electrical interference among components.
  • FIG. 13 shows one possible arrangement of three sources 120
  • the ultraviolet source 12 could also be combined with a visible light source in a manner similar to the combination shown in FIG. 1 , either using a pass through ultraviolet source or by providing an additional splitter/combiner to combine the ultraviolet and visible light.

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • Analytical Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

L'invention concerne un dispositif destiné à mesurer une matière particulaire et comprenant une source lumineuse émettant une lumière, un récepteur disposé de façon à recevoir la lumière émise à partir de cette source lumineuse, ainsi qu'une unité de détection en communication avec ce récepteur. L'unité de détection permet de détecter une quantité de matière particulaire sur la base de la lumière reçue par le récepteur.
PCT/US2002/025173 2001-08-21 2002-08-09 Structure a chemin optique pour detection d'emissions dans un chemin ouvert Ceased WO2003019160A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002331016A AU2002331016A1 (en) 2001-08-21 2002-08-09 Open path emission sensing system

Applications Claiming Priority (10)

Application Number Priority Date Filing Date Title
US09/934,272 2001-08-21
US09/934,272 US6744516B2 (en) 2001-08-21 2001-08-21 Optical path structure for open path emissions sensing
US10/028,725 2001-12-28
US10/028,724 2001-12-28
US10/028,723 US6833922B2 (en) 2001-08-21 2001-12-28 Optical path structure for open path emissions sensing with opposed sources
US10/028,725 US6744059B2 (en) 2001-08-21 2001-12-28 Optical path structure for open path emissions sensing with spinning mirror
US10/028,723 2001-12-28
US10/028,724 US6723990B2 (en) 2001-08-21 2001-12-28 Optical path structure for open path emissions sensing with spinning filter wheel
US10/142,061 2002-05-10
US10/142,061 US6900893B2 (en) 2001-08-21 2002-05-10 Optical path structure for open path emissions sensing with particulate matter and lubricating oil consumption absorption methodology

Publications (2)

Publication Number Publication Date
WO2003019160A2 true WO2003019160A2 (fr) 2003-03-06
WO2003019160A3 WO2003019160A3 (fr) 2003-08-14

Family

ID=27739434

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2002/025173 Ceased WO2003019160A2 (fr) 2001-08-21 2002-08-09 Structure a chemin optique pour detection d'emissions dans un chemin ouvert

Country Status (1)

Country Link
WO (1) WO2003019160A2 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010145809A1 (fr) * 2009-06-17 2010-12-23 Abb Ag Procédé permettant de faire fonctionner un spectromètre pour l'analyse des gaz, et spectromètre correspondant
CN103868833A (zh) * 2012-12-13 2014-06-18 张艳丽 含颗粒物空气拍摄量化评定法和装置
WO2018108650A1 (fr) * 2016-12-12 2018-06-21 HELLA GmbH & Co. KGaA Dispositif de mesure et procédé de mesure des particules fines pour véhicule automobile
CN109975224A (zh) * 2019-04-17 2019-07-05 西南交通大学 气体拍摄检测系统
WO2020260448A1 (fr) * 2019-06-28 2020-12-30 Protea Ltd Photomètre infrarouge et ultra-violet in situ
CN113588585A (zh) * 2021-06-25 2021-11-02 张玉芝 一种用于复合气体组分的快速检测方法
CN113670889A (zh) * 2021-06-25 2021-11-19 张玉芝 一种气体综合检测装置
GB2595617A (en) * 2019-06-28 2021-12-01 Protea Ltd In-situ infra-red & ultra-violet photometer
CN115753608A (zh) * 2022-11-15 2023-03-07 深圳市美思先端电子有限公司 一种单光源复合传感器
JPWO2023195066A1 (fr) * 2022-04-05 2023-10-12
CN119043662A (zh) * 2024-10-30 2024-11-29 山东中科际联光电集成技术研究院有限公司 热真空合束器测试系统及测试方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3839348A1 (de) * 1987-11-23 1989-06-01 Bosch Gmbh Robert Vorrichtung zur messung der partikelbelastung im rauch- und abgas eines verbrennungsprozesses
AT2037U1 (de) * 1997-04-03 1998-03-25 Avl List Gmbh Vorrichtung zur trübungsmessung

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010145809A1 (fr) * 2009-06-17 2010-12-23 Abb Ag Procédé permettant de faire fonctionner un spectromètre pour l'analyse des gaz, et spectromètre correspondant
CN103868833A (zh) * 2012-12-13 2014-06-18 张艳丽 含颗粒物空气拍摄量化评定法和装置
WO2018108650A1 (fr) * 2016-12-12 2018-06-21 HELLA GmbH & Co. KGaA Dispositif de mesure et procédé de mesure des particules fines pour véhicule automobile
CN110036278A (zh) * 2016-12-12 2019-07-19 黑拉有限责任两合公司 用于机动车的用于微尘测量的测量装置和方法
CN109975224B (zh) * 2019-04-17 2024-04-05 西南交通大学 气体拍摄检测系统
CN109975224A (zh) * 2019-04-17 2019-07-05 西南交通大学 气体拍摄检测系统
WO2020260448A1 (fr) * 2019-06-28 2020-12-30 Protea Ltd Photomètre infrarouge et ultra-violet in situ
GB2587780A (en) * 2019-06-28 2021-04-14 Protea Ltd In-situ infra-red & ultra-violet photometer
GB2587780B (en) * 2019-06-28 2021-10-20 Protea Ltd In-situ infra-red & ultra-violet photometer
US12104957B2 (en) 2019-06-28 2024-10-01 Protea Ltd In-situ infra-red and ultra-violet photometer
GB2595617A (en) * 2019-06-28 2021-12-01 Protea Ltd In-situ infra-red & ultra-violet photometer
GB2595617B (en) * 2019-06-28 2022-05-25 Protea Ltd In-situ infra-red & ultra-violet photometer
CN113588585A (zh) * 2021-06-25 2021-11-02 张玉芝 一种用于复合气体组分的快速检测方法
CN113670889A (zh) * 2021-06-25 2021-11-19 张玉芝 一种气体综合检测装置
JPWO2023195066A1 (fr) * 2022-04-05 2023-10-12
JP7544295B2 (ja) 2022-04-05 2024-09-03 富士電機株式会社 ガス分析計
CN115753608A (zh) * 2022-11-15 2023-03-07 深圳市美思先端电子有限公司 一种单光源复合传感器
CN119043662A (zh) * 2024-10-30 2024-11-29 山东中科际联光电集成技术研究院有限公司 热真空合束器测试系统及测试方法

Also Published As

Publication number Publication date
WO2003019160A3 (fr) 2003-08-14

Similar Documents

Publication Publication Date Title
US6900893B2 (en) Optical path structure for open path emissions sensing with particulate matter and lubricating oil consumption absorption methodology
CA1323205C (fr) Analyse multicanal d'un gaz moleculaire pour diffusion raman de lumiere activee par laser
KR100731864B1 (ko) 레이저 분광 분석 장치
US6818895B2 (en) Respiratory gas analyzer
US7274994B2 (en) Exhaust opacity measuring device
FI107194B (fi) Kaasuseosten analysointi infrapunamenetelmällä
CN106018314A (zh) 多波段多气体检测装置及方法
US9001331B2 (en) Arrangement adapted for spectral analysis of high concentrations of gas
JP4446195B2 (ja) レーザ光出力部、レーザ光入力部およびレーザ式ガス分析計
US6762410B1 (en) Analysis apparatus
WO2003019160A2 (fr) Structure a chemin optique pour detection d'emissions dans un chemin ouvert
CN205786294U (zh) 多波段多气体检测装置
US6903329B2 (en) Cooled mounting for light detector
ES2360084T3 (es) Dispositivo de medición de la opacidad de los gases de escape.
RU9311U1 (ru) Трассовый газоанализатор
Bondarchuk et al. Optic-absorption method of concentration measurements for gas-analyzer development
UA128068U (uk) Оптоелектронний датчик
UA127144C2 (uk) Сферичний оптоелектронний сенсор
HK1066058B (en) Exhaust opacity measuring device
HK1155807A (en) Exhaust opacity measuring device

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BY BZ CA CH CN CO CR CU CZ DE DM DZ EC EE ES FI GB GD GE GH HR HU ID IL IN IS JP KE KG KP KR LC LK LR LS LT LU LV MA MD MG MN MW MX MZ NO NZ OM PH PL PT RU SD SE SG SI SK SL TJ TM TN TR TZ UA UG US UZ VC VN YU ZA ZM

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ UG ZM ZW AM AZ BY KG KZ RU TJ TM AT BE BG CH CY CZ DK EE ES FI FR GB GR IE IT LU MC PT SE SK TR BF BJ CF CG CI GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP