CN211905087U - Vehicle tail gas remote measuring device based on quantum cascade laser - Google Patents
Vehicle tail gas remote measuring device based on quantum cascade laser Download PDFInfo
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- G—PHYSICS
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- 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
- G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
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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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N2021/1793—Remote sensing
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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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
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- 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
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- G—PHYSICS
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- 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
- G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
- G01N2021/396—Type of laser source
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Abstract
The utility model relates to an automobile exhaust detects technical field, in particular to vehicle exhaust remote measuring device based on quantum cascade laser contains: the quantum cascade laser is arranged in the detected gas area and used for detecting the concentrations of different gas components in the vehicle tail gas through a plurality of sets of laser sources; the quantum cascade laser is connected with the quantum cascade laser and is used for combining the light beams of the multiple sets of laser sources into one common-aperture transmitter which outputs the light beams outwards; the infrared detector array is connected with the common-aperture transmitter and is used for collecting the laser light source of the gas area to be detected; the infrared detector forms a DC signal and a harmonic phase-locked signal from the generated photoelectric signal through a phase-locked amplifier and a signal generator, feeds the DC signal and the harmonic phase-locked signal back to an upper computer, and obtains gas component inversion concentration through the upper computer to realize vehicle tail gas monitoring. The utility model discloses can realize the gas concentration detection effect of high accuracy, have stronger practicality and popularization and application and worth.
Description
Technical Field
The utility model relates to an automobile exhaust detects technical field, in particular to vehicle exhaust remote measuring device based on quantum cascade laser instrument.
Background
Currently, most motor vehicle exhaust remote sensing systems employ infrared methods and ultraviolet methods. The two methods adopt a broad spectrum light source and a filter or a spectrometer, and the difference signal value of absolute light intensity is used as an evaluation factor to reversely deduce to the target gas concentration through the beer-lambert law. In fact, the remote sensing device for the tail gas of the motor vehicle is located beside an outdoor road, and a large number of interference factors exist in the surrounding environment: vibration, rainwater, dust, noise, sunshine, these factors can directly be superimposed on the light intensity testing result, further influence the computational result of gas concentration. The traditional infrared and ultraviolet methods adopt a photo-thermal detection detector and a spectrometer, and the response time to signals is in the second level, so that an automobile to be detected is required to pass through a test area in a low-speed or static state, and the detection of the tail gas of the automobile has higher errors in the actual use process.
Disclosure of Invention
Therefore, the utility model provides a vehicle exhaust remote measuring device based on quantum cascade laser instrument realizes the gas concentration detection effect of high accuracy, can catch the vehicle exhaust pipe emission cigarette group of the in-process of traveling more fast, accurately, realizes the noninductive measurement, and it is minimum to fall to the influence of automobile normal driving safety with tail gas detection.
According to the utility model provides a design, a vehicle exhaust remote measuring device based on quantum cascade laser contains:
the quantum cascade laser is arranged in the detected gas area and used for detecting the concentrations of different gas components in the vehicle tail gas through a plurality of sets of laser sources;
the quantum cascade laser is connected with the quantum cascade laser and is used for combining the light beams of the multiple sets of laser sources into one common-aperture transmitter which outputs the light beams outwards;
the infrared detector array is connected with the common-aperture transmitter and is used for collecting the laser light source of the gas area to be detected; the infrared detector forms a DC signal and a harmonic phase-locked signal from the generated photoelectric signal through a phase-locked amplifier and a signal generator, feeds the DC signal and the harmonic phase-locked signal back to an upper computer, and obtains gas component inversion concentration through the upper computer to realize vehicle tail gas monitoring.
As the utility model discloses vehicle exhaust remote measuring device based on quantum cascade laser instrument, further, many sets of laser sources contain at least and are used for vehicle exhaust NO measuring laser source one for vehicle exhaust CO and CO2 measuring laser source two, be used for vehicle exhaust C-H compound measuring laser source three, and be used for the gaseous measuring laser source three of the opacity of vehicle exhaust.
As the utility model discloses vehicle tail gas remote measuring device based on quantum cascade laser instrument further, still contain and be used for through the appearance of making a video recording of taking a candid photograph vehicle afterbody license plate picture in order to carry out vehicle authentication, this appearance and the host computer connection of making a video recording.
As the utility model discloses vehicle exhaust telemetering device based on quantum cascade laser, further, quantum cascade laser contains integration multispectral light source transmission and receiving host computer, and reflection end; the host and the reflection end are respectively and horizontally arranged and fixed at two sides of the road of the detected gas area.
As the utility model discloses vehicle exhaust remote measuring device based on quantum cascade laser instrument, furtherly, the host computer includes the box, and locates the cascaded laser source of the content value in the box, protection window, light detector, mark gas air inlet, nitrogen gas air inlet and gas vent.
As the utility model discloses vehicle exhaust remote measuring device based on quantum cascade laser instrument, further, still contain the plate radar that tests the speed that is used for vehicle speed/acceleration to detect, this plate radar that tests the speed and upper computer connection.
As the utility model discloses vehicle exhaust remote measuring device based on quantum cascade laser instrument further, still contains the environmental monitoring equipment who is used for environmental meteorological measurement with the host computer connection.
As the utility model discloses vehicle exhaust remote measuring device based on quantum cascade laser instrument, furtherly, environmental monitoring equipment contains air velocity transducer, wind direction sensor, air humidity transducer, air temperature sensor, baroceptor and slope angle sensor.
As the utility model discloses vehicle tail gas remote measuring device based on quantum cascade laser instrument, furtherly, infrared detector adopts the infrared detector based on indium arsenic antimony InAsSb material is in order to realize quantum formula photoelectric conversion and four wavelength laser sharing.
The utility model has the advantages that:
the device of the utility model has scientific and reasonable design, and adopts the quantum cascade laser to ensure the one-to-one correspondence between the tail gas measurement result and the target gas, and eliminate the cross interference generated by air backgrounds such as nitrogen, oxygen, water vapor, carbon dioxide and the like; through the laser detector and the lock-in amplifier, under the condition that the automobile moves at a high speed, the smoke discharged by the exhaust pipe in the running process can be captured more quickly and accurately, so that non-inductive measurement is realized, and the influence of exhaust detection on the normal running safety of the automobile is reduced to the minimum; the method can realize that the frequency modulation of the laser wavelength of the quantum cascade laser and the demodulation of a specific frequency point are utilized to obtain a harmonic signal which is used as an evaluation factor, completely eliminate the influence of environmental disturbance factors, and really establish the unique correlation from the gas concentration to the evaluation factor, thereby realizing the high-precision gas concentration detection effect, avoiding the misinformation caused by error data, and having strong practicability and popularization and application values.
Description of the drawings:
FIG. 1 is a schematic diagram of the structure of the apparatus in the example;
FIG. 2 is a schematic diagram of the operation of the apparatus according to the embodiment;
FIG. 3 is a schematic diagram illustrating a state of use of the apparatus according to one embodiment;
FIG. 4 is a diagram illustrating the working principle of a quantum cascade laser in an embodiment;
FIG. 5 is a schematic diagram of a quantum cascade laser host structure in an embodiment;
FIG. 6 is a schematic diagram of a reflection end structure of a quantum cascade laser in an embodiment;
FIG. 7 is a second schematic diagram illustrating the operation state of the apparatus in the embodiment;
FIG. 8 is a diagram of an exemplary application platform.
The specific implementation mode is as follows:
the present invention will be described in further detail with reference to the accompanying drawings and technical solutions, and embodiments of the present invention will be described in detail by way of preferred examples, but the embodiments of the present invention are not limited thereto.
Automobile exhaust emission is one of the main causes of atmospheric pollution. In order to detect whether the exhaust emission of the automobile reaches the standard, a parking detection mode in a fixed place is usually adopted, so that the mode is low in efficiency, and along with the continuous improvement of the automobile holding capacity in China, the traditional detection mode brings inconvenience to supervision departments and automobile owners. A novel tail gas detection technology is researched and developed, so that the tail gas detection technology has the working characteristics of road field and no-parking mobile mode, and meanwhile, the detection precision can meet the industrial standard, and the tail gas detection technology has important application value. As gas molecules have spectral absorption characteristics in an infrared band and different components have different absorption central peaks, the gas is detected by an infrared spectrum absorption method, so that not only can the concentration of the gas be measured, but also the components of the gas can be judged by unique absorption spectrum fingerprints of the gas. The traditional spectrum absorption methods include NDIR (non-dispersive infrared) and DOAS (differential absorption spectroscopy) technologies, but are limited by the types of light sources (usually tungsten lamps, mercury lamps and other incoherent light sources), so that the effective operating distances of the measurements cannot be prolonged, Open-path measurement configurations cannot be realized, and the interference resistance is poor, so that the method is not suitable for road field flow detection. The embodiment of the utility model provides a, it is shown with reference to fig. 1, provide a vehicle exhaust remote measuring device based on quantum cascade laser instrument, contain: the quantum cascade laser is arranged in the detected gas area and used for detecting the concentrations of different gas components in the vehicle tail gas through a plurality of sets of laser sources; the quantum cascade laser is connected with the quantum cascade laser and is used for combining the light beams of the multiple sets of laser sources into one common-aperture transmitter which outputs the light beams outwards; the infrared detector array is connected with the common-aperture transmitter and is used for collecting the laser light source of the gas area to be detected; the infrared detector forms a DC signal and a harmonic phase-locked signal from the generated photoelectric signal through a phase-locked amplifier and a signal generator, feeds the DC signal and the harmonic phase-locked signal back to an upper computer, and obtains gas component inversion concentration through the upper computer to realize vehicle tail gas monitoring.
The quantum cascade laser can ensure that the tail gas measurement result corresponds to the target gas one by one, and eliminate the cross interference generated by air backgrounds such as nitrogen, oxygen, water vapor, carbon dioxide and the like; through the laser detector and the lock-in amplifier, under the condition that the automobile moves at a high speed, the smoke discharged by the exhaust pipe in the running process can be captured more quickly and accurately, so that non-inductive measurement is realized, and the influence of exhaust detection on the normal running safety of the automobile is reduced to the minimum; the method can realize that the frequency modulation of the laser wavelength of the quantum cascade laser and the demodulation of a specific frequency point are utilized to obtain a harmonic signal which is used as an evaluation factor, completely eliminate the influence of environmental disturbance factors, and really establish the unique correlation from the gas concentration to the evaluation factor, thereby realizing the high-precision gas concentration detection effect, avoiding the misinformation caused by error data, and having strong practicability and popularization and application values.
As the embodiment of the utility model provides a vehicle exhaust remote measuring device based on quantum cascade laser instrument, further, many sets of laser sources contain at least and are used for vehicle exhaust NO measuring laser source one for vehicle exhaust CO and CO2 measuring laser source two, are used for vehicle exhaust C-H compound measuring laser source three, and are used for vehicle exhaust opacity gas measuring laser source three.
Referring to fig. 2, concentration measurement of four types of gas components is realized by using three sets of QCL laser sources, wherein CO and CO2 can share one set of laser, QCL1 is 5.26 μm, and NO measurement is performed; QCL2 is 4.48 μm, measured with CO and CO 2; QCL3 is 3.37 μm, C-H compound measurement; DPSS was 0.53 μm, measured by opacity. QCL laser carries out collimation and transmission through infrared optical element, synthesizes into a bundle through the common aperture transmitter and exports outward, and after waiting to examine the gas area, laser is collected by infrared detector array. The first method is to adopt a corner reflector to reflect the light beam back to the emitting position, so as to realize that the laser emission and the detection are positioned at the same side; the second is a correlation structure. The laser emission and detection are positioned at two sides. Three sets of lasers are independently and parallelly equipped with a gas detection schematic diagram as shown in fig. 4, namely: and converting the light intensity signal into an absorption numerical value through DC analysis or harmonic analysis, and displaying the absorption numerical value in real time in monitoring software. The three systems are completely independent and do not influence each other. Through sample gas calibration, the conversion from the absorption value to the concentration of the gas to be measured can be realized, and thus, the concentration measurement is realized. In addition, a DPSS laser is adopted for carrying out opacity measurement, and the DPSS laser intensity after passing through an exhaust region is measured through a photoelectric detector, so that the opacity value is measured and calculated, and is synchronously displayed and recorded in the software of an upper computer, and the device has the characteristics of no adjustment of an optical path, simplicity in installation and erection, convenience in operation and the like. For four main components in motor vehicle exhaust: CO, CO2, CH and NO are all measured by adopting a distributed feedback quantum cascade laser (DFBQCL) tuned spectrum technology, the DFBQCL has extremely narrow line width, and gas corresponding to absorption spectrum can be selectively measured by wavelength scanning and harmonic extraction technology, so that cross interference of adjacent spectral lines of the same gas and other gases is avoided, and the concentration measurement result is more accurate. This is an effect that is not achievable with infrared, ultraviolet or broad spectrum QCLs.
In fig. 4, the signal generator generates a modulation signal having a specific pattern, which includes both low frequency sweep and high frequency oscillation components, which is applied to the current tuning driver and applied to the QCL to generate an equivalent wavelength tuning waveform. The QCL light beam generates infrared spectrum absorption through a light path of a tail gas region to be detected, and then the infrared spectrum absorption is irradiated onto an infrared detector through a light collection system. The detector generates a photoelectric signal, the photoelectric signal enters the phase-locked amplifier and is referenced by the signal generator to form a DC signal and a harmonic phase-locked signal; in the upper computer data acquisition platform, the inversion concentration of the gas component to be detected is obtained by adopting a harmonic extraction algorithm, and is visually displayed and stored in a concentration-time curve form, so that the monitoring of the automobile exhaust is realized.
The basic principle of QCLAS harmonic detection is to "scan" a characteristic signal to be detected by frequency modulation (e.g., sinusoidal modulation), and to generate a harmonic signal whose intensity is proportional to the concentration of a gas to be detected by using a frequency-locked amplification technique using a frequency-doubled signal of modulation frequency or modulation frequency as a reference signal, thereby realizing concentration detection. The theoretical basis of harmonic detection is fourier transform, and the absorption characteristics of the gas to be detected can be described by certain mathematical models, such as Lorentz, Guassian and Voigt line types. When the absorption coefficient of the gas is known, the gas concentration can be obtained.
The QCL driving current is sinusoidally modulated, and the light intensity and wavelength thereof produce corresponding modulation effects, and are proportional to the modulation injection current:
I′0(v,t)＝I0(v,t)[1+nsin(ωt)] (2)
v＝v0+vfsin(ωt) (3)
wherein: n is the light intensity modulation factor, v0Is the central wavelength, v, of the light source without modulationfFor wavelength modulation amplitude, ω is the sinusoidal modulation frequency coefficient.
Substituting the above formulas (2) and (3) into the Belronbo law formula, and simultaneously adopting a tiny approximation (in the near infrared band, the light intensity modulation coefficient and the gas absorption coefficient are both very small, and satisfy-a (v) LC < 1 and n < 1), the method can obtain:
at one standard atmosphere, the collisional broadening of infrared spectrum particles plays a major role, and normalized Lorentz linearity can be used to describe the absorption coefficient of a (v) for gases as follows:
wherein a is0Is the absorption cross section of the pure gas at the center of the absorption line, vcIs the central absorption peak and Δ v is the absorption line full width at half maximum. The Lorentz absorption coefficient line type is substituted into the tuning strength expression, and the following can be obtained:
when the output center wavelength of the light source is precisely locked at the absorption peak of the gas, v0＝vcThen, then
Wherein
The coefficients of the first harmonic (f) and second harmonic terms (2f) can be obtained by expanding equation (7) in a fourier series as follows:
If＝nI0 (9)
I2f＝-ka0LCI0 (10)
wherein
Due to the fact that
Is a constant and therefore k is also a constant associated with the absorption center peak.
It can be concluded that: the first harmonic signal is mainly caused by light intensity modulation, and the magnitude of the first harmonic signal is in direct proportion to the average power of a light source; the size of the second harmonic signal is related to the initial light intensity and the concentration of the gas, and the concentration information of the gas can be deduced by lifting the second harmonic signal. In addition, as the harmonic order is increased, the harmonic amplitude is reduced rapidly, which is not beneficial to improving the signal-to-noise ratio of detection, therefore, the second harmonic extraction technology can be used as a main means for detecting the gas concentration of QCLAS, and the adopted method can utilize the 2f harmonic detection principle of the lock-in amplifier. By modulating the wavelength of the quantum cascade laser and demodulating a specific frequency point, a harmonic signal is obtained and used as an evaluation factor, the influence of environmental disturbance factors can be completely eliminated, and the unique correlation from the gas concentration to the evaluation factor is really established, so that the high-precision gas concentration detection effect is realized, and the false alarm caused by wrong data is avoided.
As the embodiment of the utility model provides an in vehicle tail gas remote measuring device based on quantum cascade laser instrument, further, still contain and be used for through the appearance of making a video recording of taking a candid photograph vehicle afterbody license plate picture in order to carry out vehicle authentication, this appearance and the host computer connection of making a video recording. Referring to fig. 3, a light source emitter directly emits a light source to a reflector opposite to a road, and then an absorbed light source is directly emitted to the opposite reflector by a quantum cascade laser by using a long-optical-path absorption spectrum and is reflected to a detector, so that the detection of the instantaneous emission concentration of the tail gas of the vehicle is realized; the camera shoots the images of the license plate at the tail part of the vehicle so as to be used for further realizing the vehicle identity confirmation through the upper computer.
As the vehicle tail gas remote measuring device based on the quantum cascade laser in the embodiment of the utility model, further, the quantum cascade laser comprises an integrated multispectral light source transmitting and receiving host and a reflecting end; the host and the reflection end are respectively and horizontally arranged and fixed at two sides of the road of the detected gas area.
Referring to fig. 5 and 6, the remote measurement optical path system measurement is realized by using a remote measurement device composed of an integrated multispectral light source transmitting end and receiving end and a reflecting end, and the integrated multispectral light source transmitting end and receiving end, which are used as a host, comprise a box body, and a content value cascade laser light source, a protective window, a light detector, a standard gas inlet, a nitrogen/air inlet and an exhaust port which are arranged in the box body. The host can adopt high-precision laser light path integration, and can detect the exhaust emission of gasoline vehicles, diesel vehicles and CNG vehicles simultaneously. The reflection end adopts a sapphire mirror window, and a light source is reflected and collected in two ways, so that the data precision is greatly improved, and the capture probability is enhanced. The road condition of the installation point can be a one-way lane, the transmitting end and the reflecting end of the remote measuring equipment are respectively and horizontally installed and fixed on two sides of the road, the horizontal optical path can be far more than 5 meters, the measurement triggering mode can adopt smoke mass triggering and light blocking triggering (the data capture rate of a long vehicle is improved), and the effective data recognition rate can reach more than 85% through actual testing.
As the embodiment of the utility model provides an in vehicle exhaust remote measuring device based on quantum cascade laser instrument, further, still contain the flat radar that tests the speed that is used for vehicle speed/acceleration to detect, this flat radar that tests the speed and upper computer connection. In order to ensure the measuring accuracy, the device is erected on the door-shaped rod in a single-lane corresponding mode.
As the embodiment of the utility model provides an in vehicle exhaust remote measuring device based on quantum cascade laser instrument, further, still contain and be used for the environmental monitoring equipment of environmental meteorological measurement with the host computer connection. Furthermore, according to the actual environment monitoring parameter requirement, the environment monitoring device can be set to at least comprise a wind speed sensor, a wind direction sensor, an air humidity sensor, an air temperature sensor, an air pressure sensor and a gradient angle sensor so as to measure the data of wind speed, wind direction, air temperature and humidity, air pressure, gradient and the like in the tested area.
As the embodiment of the utility model provides an in vehicle tail gas remote measuring device based on quantum cascade laser instrument, further, infrared detector adopts the infrared detector based on indium arsenic antimony InAsSb material is in order to realize quantum formula photoelectric conversion and four wavelength laser sharing. Quantum type photoelectric conversion is realized through InAsSb materials. Compared with a common pyroelectric detector or MCT detector, the pyroelectric detector has the advantages that: the response speed is high: the photoelectric conversion speed reaches the nano-second order, and the requirement of detection on response time in the motion process of the motor vehicle is met; the spectrum range is wide: the InAsSb covers a super-wide infrared spectrum area of 2-8 um, so that a four-in-one structure of a detector for common use of four-wavelength laser becomes possible; the response is sensitive; the InAsSb has ultrahigh photoelectric conversion efficiency, and can be suitable for application scenes with high laser loss and weak return light in outdoor sites.
Referring to fig. 7, an exhaust gas detection device, a speed and acceleration measurement device, a license plate camera, an exhaust gas analyzer, a data processing device, a monitor and the like are installed at a proper monitoring place, so that the vehicle is detected in an acceleration state of a normal load, and the detected vehicle is prevented from running in a neutral gear state, a deceleration state or an excessive horsepower state. The optimal conditions of traffic conditions and the installation place of the instrument are that the traffic flow is 200-3600 vehicles per hour. The average speed is between (10-110) km/h. The vehicle is preferably under slight acceleration (small fueling of the engine) to produce a strong emission plume. Proper distance is required between two following vehicles to avoid the influence of overlapping of smoke plumes discharged by the two vehicles on the test. And selecting a single-way lane or a bridge approach entrance with a slight upward slope to set a measuring point. And arranging a measuring point in a one-way lane for accelerating and driving away of the vehicle after the toll is paid at the highway toll station. The proper monitoring place needs to be determined through investigation and analysis and field tests, and after the monitoring place is determined, the specific position of the instrument needs to be adjusted through tests so as to find the optimal setting point position.
As shown in fig. 8, the system platform integrating multiple functions of remote sensing monitoring of tail gas of motor vehicles, video capture of vehicles exceeding standards, real-time data matching, remote online monitoring and the like can supervise dust emission, yellow-brand banning and other behaviors when vehicles exceeding the standards, such as yellow-brand trucks, muck vehicles and the like are found. The system is reasonably arranged in each typical region of the urban area to form an online monitoring network, combines a network transmission technology with an environment monitoring center and a vehicle management center to carry out data sharing and result display, and provides scientific basis for decision researchers and the specification of regional motor vehicle tail gas pollution control measures, thereby achieving the purpose of online monitoring of the pollutants of the motor vehicles in the whole city.
The gas of spectrum is selectively absorbed by a quantum cascade laser, so that the cross interference of adjacent spectral lines of the same gas and other gases is avoided, a plurality of paths of laser light sources are combined into a beam through an aperture-providing optical emission system to be output outwards, the signal is measured by an infrared detector, and the concentration of various gases in the tail gas of the vehicle is respectively detected by frequency division phase-locked amplification.
The embodiment of the utility model provides an in, can obtain harmonic signal and as the evaluation factor through the frequency modulation to the wavelength of quantum cascade laser and the demodulation of specific frequency point, can get rid of the influence of environmental disturbance factor completely, really establish from "gas concentration" to the only correlation between the "evaluation factor" to realize the gas concentration detection effect of high accuracy, stop the false positive that the wrong data leads to. The quantum cascade laser is adopted, the emission wavelength of the quantum cascade laser is positioned in a middle and far infrared region, and the target gas has the strongest absorption peak in the spectral range, so that the lower limit concentration of gas detection can be obviously improved; furthermore, quantum cascade lasers have extremely narrow spectral lines, and therefore can ensure that only valid signals are generated for the target gas, and cross interference between unrelated gases is not present. Through the laser detector and the phase-locked amplifier, the response time is millisecond level, and the smoke discharged by the tail gas pipe in the driving process can be captured more quickly and accurately under the condition of high-speed movement of the automobile, so that non-inductive measurement is realized, and the influence of tail gas detection on the normal driving safety of the automobile is reduced to the minimum.
It is to be understood that the foregoing description of specific exemplary embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
The term "and/or" herein means that three relationships may exist. For example, a and/or B may represent: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter associated objects are in an "or" relationship.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the description and claims of this application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not necessarily denote a limitation of quantity. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
Exemplary embodiments of the present invention have been described in detail with reference to the preferred embodiments, however, it will be understood by those skilled in the art that various modifications and changes may be made to the above specific embodiments without departing from the scope of the present invention, and various combinations of the technical features and structures of the present invention may be implemented without departing from the scope of the present invention, which is defined by the appended claims.
Claims (9)
1. A vehicle exhaust telemetering device based on a quantum cascade laser is characterized by comprising:
the quantum cascade laser is arranged in the detected gas area and used for detecting the concentrations of different gas components in the vehicle tail gas through a plurality of sets of laser sources;
the quantum cascade laser is connected with the quantum cascade laser and is used for combining the light beams of the multiple sets of laser sources into one common-aperture transmitter which outputs the light beams outwards;
the infrared detector array is connected with the common-aperture transmitter and is used for collecting the laser light source of the gas area to be detected;
the infrared detector forms a DC signal and a harmonic phase-locked signal from the generated photoelectric signal through a phase-locked amplifier and a signal generator, feeds the DC signal and the harmonic phase-locked signal back to an upper computer, and obtains gas component inversion concentration through the upper computer to realize vehicle tail gas monitoring.
2. The vehicle exhaust telemetry device based on quantum cascade laser as claimed in claim 1, wherein the multiple sets of laser sources at least comprise a first laser source for vehicle exhaust NO measurement, a second laser source for vehicle exhaust CO and CO2 measurement, a third laser source for vehicle exhaust C-H compound measurement, and a third laser source for vehicle exhaust opacity gas measurement.
3. The vehicle tail gas telemetering device based on the quantum cascade laser as claimed in claim 1, further comprising a camera for vehicle identity verification by capturing a picture of a license plate at the tail of the vehicle, wherein the camera is connected with an upper computer.
4. The vehicle exhaust telemetering device based on a quantum cascade laser as claimed in claim 1, wherein the quantum cascade laser comprises an integrated multispectral light source transmitting and receiving host and a reflecting end; the host and the reflection end are respectively and horizontally arranged and fixed at two sides of the road of the detected gas area.
5. The vehicle exhaust telemetering device based on a quantum cascade laser as claimed in claim 4, wherein the host comprises a box, and a laser light source, a protection window, a light detector, a marker gas inlet, a nitrogen/air inlet and an exhaust port which are arranged in the box and have cascaded content values.
6. The device of claim 1, further comprising a flat plate type speed radar for detecting vehicle speed/acceleration, wherein the flat plate type speed radar is connected to the host computer.
7. The quantum cascade laser-based vehicle exhaust telemetry device of claim 1, further comprising an environmental monitoring device connected to the upper computer for environmental weather measurement.
8. The quantum cascade laser-based vehicle exhaust telemetry device of claim 7, wherein the environmental monitoring equipment comprises an air speed sensor, a wind direction sensor, an air humidity sensor, an air temperature sensor, an air pressure sensor, and a grade angle sensor.
9. The quantum cascade laser-based vehicle exhaust telemetry device of claim 1, wherein the infrared detector is made of InAsSb material to realize quantum photoelectric conversion and common use of four-wavelength laser.
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| EP4290218A1 (en) * | 2022-06-07 | 2023-12-13 | Josefina de la Fuente Egido | Equipment for measuring pollutant emissions on multi-lane roads emitted by motor vehicles by means of laser spectroscopy using light intensity absorption devices |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| EP4290218A1 (en) * | 2022-06-07 | 2023-12-13 | Josefina de la Fuente Egido | Equipment for measuring pollutant emissions on multi-lane roads emitted by motor vehicles by means of laser spectroscopy using light intensity absorption devices |
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