CN102798609B - Automobile exhaust remote sensing detection system and method based on quantum cascade laser - Google Patents
Automobile exhaust remote sensing detection system and method based on quantum cascade laser Download PDFInfo
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- 230000008569 process Effects 0.000 claims description 20
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 19
- 238000013528 artificial neural network Methods 0.000 claims description 18
- 238000012886 linear function Methods 0.000 claims description 18
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- HGAZMNJKRQFZKS-UHFFFAOYSA-N chloroethene;ethenyl acetate Chemical compound ClC=C.CC(=O)OC=C HGAZMNJKRQFZKS-UHFFFAOYSA-N 0.000 description 12
- 239000003570 air Substances 0.000 description 7
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- 231100000719 pollutant Toxicity 0.000 description 2
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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
- 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
-
- 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
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/03—Cuvette constructions
- G01N21/031—Multipass arrangements
- G01N2021/0314—Double pass, autocollimated path
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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
- 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
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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
- 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
- G01N2021/399—Diode laser
Abstract
The invention discloses an automobile exhaust remote sensing detection system and a method based on a quantum cascade laser. According to the invention, a signal generated by any function generator is input into a laser current pulse driving module; the quantum cascade laser is driven by the laser current pulse driving module to generate intermediate-infrared or far-infrared laser; a modulation signal is obtained through a chopper after the intermediate-infrared or far-infrared laser passes through an automobile exhaust emission area; a pyroelectric sensor module detects the modulated intermediate-infrared or far-infrared laser signal, and then inputs the detected signal into a lock-in amplifier for operation; the lock-in amplifier outputs the data into a computer; and the computer calculates the contents of different emission products in the automobile exhaust through a data processing method analysis method.
Description
Technical field
The invention belongs to motor vehicle exhaust emission detection technique field, particularly relate to a kind of remote vehicle emissions measurement system based on quantum cascade laser and method.
Background technology
Along with the fast development of China's economy, automobile pollution sustainable growth, the pollution of harmful waste gas of motor vehicle emission has become one of main source of China's urban atmospheric pollution.According to the statistics of environmental administration, in urban air pollution 20% CO
2, the CO of 60 ~ 70%, the NO of 40%
xvehicle exhaust is come from the HC of 70%.Such as, Beijing and the ratio of Guangzhou automotive emissions in surrounding air, carbon monoxide (CO) accounts for more than 80%, oxides of nitrogen (NO
x) account for more than 40%.For controlling the discharge of automobile exhaust pollution thing, the laws and regulations of restricting vehicle toxic emission have all successively been formulated in countries in the world and area.China comes into effect " light-duty vehicle pollutant emission limit and measuring method (Chinese III, IV the stage) " emission standard being equivalent to European III regulation from July, 2007.But compared with developed countries, the discharge present situation of China's vehicle exhaust still allows of no optimist: vehicle emission pollution management is started late; The pollution situation that the vehicle exhaust of key cities causes is very serious; Assembly relevant to discharge on vehicle is short of very much.In order to improve Area Ambient Air Quality, the exhaust emission of reduction and control vehicle exhaust is own through very urgent.
The monitoring method of the vehicle exhaust that China is existing mainly contains operating condition method and slack speed method.At present, these two kinds of methods are all main just can complete test on the experiment test platform of auto producer or in vehicle annual test place, and cannot realize Real-Time Monitoring for the exhaust emissions process of automobile in the process of moving.In actual travel process, the exhaust emissions of automobile not only depends on the structure of automobile itself, also depends on the factors such as the degree of crowding of fuel composition that automobile uses, load, drive manner and traffic.Remote vehicle emissions monitoring technology is the vehicle exhaust monitoring technology of a kind of advanced person, it can realize monitoring to the instantaneous discharge of vehicle exhaust in automobile normal running situation, identify the pollution vehicle that discharge is not up to standard, for the monitor and forecast of city automobile tail gas pollution provides effective means, huge social demand is thus had to be studied widely and pay close attention to.
The remote-sensing monitoring method of traditional vehicle exhaust is mainly for CO
2, the Non-Dispersive Infra-red (NDIR) method that CO and HC detects.Mostly the testing conditions that discharges pollutants is under idling condition, cannot reflect the photochemical reaction that the characteristic of the harmful tailpipe emissions of automobile under driving conditions and tail gas may be formed in atmosphere." a kind of many idling Design of Vehicle Tail Gas Analyzer " of the automobile exhaust gas checking apparatus if the patent No. is CN2440208Y of prior art needs flexible pipe to be connected to the detection analysis vehicle exhaust mouth of pipe just carrying out CO and HC in tail gas." infrared laser detection system detect in real time vehicle exhaust and method " that the patent No. is CN1412541A is used a kind of Non-Dispersive Infra-red (NDIR) analyser, it does not have spectral resolution, and the tail gas kind detected is comparatively single, can only detect the concentration of CO and HC.CO, CO is developed into from the detection of single CO and HC concentration
2, HC, NO
x, NH
3and SO
xdetection Deng Multiple components is the direction that current remote vehicle emissions detects.At present, remote vehicle emissions detection technique in many countries such as the U.S., Canada, Australia, Sweden, Brazil, Singapore and India all in positive development process.
Quantum cascade laser, having started the beginning utilizing wide bandgap material to develop mid and far infrared semiconductor laser, is the milestone of semiconductor laser theory, is just becoming the cutting edge technology that countries in the world fall over each other to follow the trail of.Quantum cascade laser has the advantages such as monochromaticity is good, quantum efficiency is high, temperature stability is good, Wavelength design is flexible, intrinsic fast response time.Quantum cascade laser has broad application prospects in gas detect, especially in light concentration gas, atmospheric trace gas detection, quantum cascade laser has the unrivaled advantage of conventional semiconductor laser, can be widely used in coal mine mash gas height sensitivity technique, vehicle exhaust and industrial gaseous waste and detect.
Summary of the invention
The object of the invention is for the deficiencies in the prior art, a kind of remote vehicle emissions measurement system based on quantum cascade laser and method being provided, realizing the remote sensing detection to road travelling car exhaust gas.
The technical solution adopted for the present invention to solve the technical problems is as follows:
Based on the remote vehicle emissions measurement system of quantum cascade laser, comprise arbitrary-function generator, current impulse driver module, quantum cascade laser, tygon collimation focusing lens, spectroscope, chopper, pyroelectric sensor module, gold-plated corner cube mirror, lock-in amplifier, computing machine;
The voltage signal that arbitrary-function generator produces is input to current impulse driver module, again by current impulse driver module generation current pulsed drive quantum cascade laser, quantum cascade laser launches the mid and far infrared laser of which amplitude modulation under the driving of current impulse, mid and far infrared laser is by tygon collimation focusing collimated exiting parallel, parallel mid and far infrared laser is divided into reference path and detection light path through spectroscope, the mid and far infrared laser of reference path is detected by the pyroelectric sensor module of reference path after chopper modulation, the mid and far infrared laser of detection light path is reflected by gold-plated corner cube mirror through the motor vehicle exhaust emission region in traveling, mid and far infrared laser after reflection is through chopper, detected by the pyroelectric sensor module of detection light path after tygon collimation focusing lens, the sine-wave signal components of detection the pyroelectric sensor module of light path, the pyroelectric sensor module of reference path and arbitrary-function generator inputs in lock-in amplifier respectively and carries out related calculation, and result is outputted to computing machine by lock-in amplifier, computing machine does additive operation with reference to the related operation output valve of the related operation output valve of the pyroelectric sensor module of light path and the pyroelectric sensor module of detection light path, and the process of data and the analysis of spectrum are carried out to result of calculation, finally obtain the measurement result of vehicle exhaust.
Described spectroscope is arranged on tygon collimation focusing lens dead ahead, and at 45 ° with the light of tygon collimation focusing collimated exiting parallel;
Described arbitrary-function generator produces three kinds of signals respectively: rectangular pulse signal, sawtooth signal and sine wave signal, inner by these three kinds of rear input current pulsed drive modules of voltage signal superposition at arbitrary-function generator, current impulse driver module carrys out drive volume qc laser by the current signal exported after Voltage to current transducer through ovennodulation, sine-wave signal components in superposed signal is input to the related operation that lock-in amplifier carries out signal by arbitrary-function generator while output superposed signal to current impulse driver module, lock-in amplifier is connected to computing machine.
Described pyroelectric sensor module comprises pyroelectric sensor, resistance, filter capacitor; 1 pin of pyroelectric sensor connects one end of DC voltage VCC and filter capacitor simultaneously, one end of 2 pin connecting resistances, the other end ground connection simultaneously of 3 pin and resistance, and the other end of filter capacitor is connected with lock-in amplifier; AC signal input lock-in amplifier after filtering after electric capacity, the sinusoidal ac signal that lock-in amplifier exports simultaneously drives chopper to rotate with certain frequency, and lock-in amplifier is connected to computing machine; Tygon collimation focusing lens and chopper are placed on pyroelectric sensor module dead ahead.
Based on the remote vehicle emissions detection method of quantum cascade laser, comprise the steps:
Step (1). the original spectral data that lock-in amplifier output measurement obtains is to computing machine;
Step (2). the random noise in original spectral data is removed according to the method for the frequency usage mean filter function of sawtooth wave in arbitrary-function generator, in concrete employing composite signal, the cycle of sawtooth signal realizes mean filter, obtains the spectroscopic data of the different wave length under frequency sweep after filtering;
Step (3). first filtered spectroscopic data uses the matching of Fu Yite (Voigt) linear function, and Fu Yite (Voigt) linear function that fitting function adopts is described by formula (1).
Wherein,
γ
d--Gaussian linear function spectral width;
γ
c-Lorentz linear function spectral width;
Fu Yite linear function spectral width Δ v can be obtained simultaneously
v:
Wherein: Δ v
cit is the collision live width of spectral line; Δ v
dit is the doppler linewidth of spectral line;
Step (4). use Fu Yite (Voigt) linear function to repeat n matching, the spectral distribution data Φ of the different spectral line of n bar can be obtained
v, according to ambiguity function degree of membership determination methods, most probable absorption line is shown to any spectrum line data that matching obtains, if the set of measuring the spectroscopic data of i-th spectral line obtained is U={u
i1, u
i2, u
i3... u
im, the set of the standard spectral data of i-th spectral line is V={v simultaneously
i1, v
i2, v
i3... v
im, wherein i is natural number, and i is less than or equal to m; M is natural number; Then the coefficient of similarity r of set U and set V is calculated
uv(i):
If coefficient of similarity r
uv(i)>=λ
uvi () then corresponding spectral line is judged as absorption line, thus to obtain i-th spectral line be effective absorption line, wherein λ
uvi () is the level value demarcated in advance;
Step (5). finally the artificial neural network of the spectroscopic data of effective absorption line input precondition and demarcation is processed, drawn the concentration Y of gas with various in vehicle exhaust by artificial neural networks
j(X), wherein X={X
1, X
2..., X
iit is the spectroscopic data of effective absorption line.
Level value λ in ambiguity function degree of membership determination methods in described step (4), step (5)
uvi the parameter calibration flow process of () and artificial neural network is specific as follows:
The angle of (a) fixing gold-plated plane mirror, quantum cascade laser and pyroelectric detector and position; The position of fixing long path cell and heating arrangement; Under collection room temperature condition, the spectrum of pure air exports numerical value;
B the vehicle exhaust of simulation, by being mixed in varing proportions by clean gas thus vehicle exhaust under simulating different operating mode, is filled with long path cell as gas to be calibrated in calibration process by ();
The kind of described clean gas comprises CO, CO
2, NO, NO
2, NH
3and SO
2;
(c) around long path cell around on heater coil to the air homogeneous heating in long path cell, the air themperature in long path cell is changed along with the change of setting model, gathers the spectroscopic data output valve under different temperatures;
One end of described long path cell arranges gold-plated corner cube mirror, the pyroelectric sensor module of other end set amount qc laser and detection light path.
D (), according to the actual mixture ratio example of the vehicle exhaust of spectroscopic data output valve and simulation, training obtains ambiguity function degree of membership level value λ
uvi () and artificial neural network parameter, obtain ambiguity function degree of membership level value λ according to the mean value of N different measuring result
uvi (), utilizes this data sample training of human artificial neural networks simultaneously; If the resultant error of demarcating is greater than 20%, then need again to demarcate; Otherwise end calibration process.
Beneficial effect of the present invention is as follows:
The first, the voltage signal drive volume qc laser that the remote vehicle emissions measurement system based on quantum cascade laser uses arbitrary-function generator to produce, quantum cascade laser launches the mid and far infrared laser of different wave length.The very fast spectrum swept-frequency signal of sweep velocity can be obtained by the repetition frequency and amplitude that change sawtooth signal in voltage signal, thus obtain results of spectral measurements fast.Due to the speed of one-shot measurement, therefore based on quantum cascade laser remote vehicle emissions measurement system can in the car speed and low speed driving process in, under the condition not disturbing automobile normal running, adopt non-contacting mode measurement to obtain vehicle exhaust concentration data.
The second, quantum cascade laser can launch the mid and far infrared laser that wavelength can regulate on a large scale, and due to the laser frequency spectrum wide coverage of launching, the gaseous species therefore can measured is more, can complete CO, CO in one-shot measurement process
2, NO, NO
2, NH
3and SO
2deng the concentration monitor of gas.Owing to only needing a quantum cascade laser as spectral radiation source, the remote vehicle emissions measurement system structure therefore based on quantum cascade laser is very simply compact.Simultaneously because mid and far infrared laser is for the very high sensitivity of vehicle emission component, therefore, it is possible to realize the sensitive detection of vehicle emission component.
3rd, the remote vehicle emissions measurement system based on quantum cascade laser can be arranged on the different road of width on both sides of the road flexibly according to road actual conditions.Adjustment is placed on the angle of road gold-plated corner cube mirror on one side, and the mid and far infrared laser reflected in parallel that quantum cascade laser is sent returns to be received by the detection of pyroelectric sensor module.The spectral data disposal route adopted, can be realized the data processing under complex road condition and emission from vehicles situation and analysis by intelligent algorithms such as the judgement of ambiguity function degree of membership and artificial neural networks.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention;
Fig. 2 is quantum cascade laser driving circuit structure schematic diagram;
Fig. 3 is pyroelectric sensor module testing circuit structural representation;
Fig. 4 is spectroscopic data handling procedure process flow diagram;
Fig. 5 is level value λ in ambiguity function degree of membership discriminant function
uvthe parameter calibration process flow diagram of (i) and artificial neural network.
Embodiment
Below in conjunction with accompanying drawing, the present invention is described in further detail.
As shown in Figure 1, based on the remote vehicle emissions measurement system of quantum cascade laser, comprise arbitrary-function generator 1, current impulse driver module 2, quantum cascade laser 3, tygon collimation focusing lens 4, spectroscope 5, chopper 6, pyroelectric sensor module 7, gold-plated corner cube mirror 8, lock-in amplifier 9, computing machine 10;
The voltage signal that arbitrary-function generator 1 produces is input to current impulse driver module 2, again by current impulse driver module 2 generation current pulsed drive quantum cascade laser 3, quantum cascade laser 3 launches the mid and far infrared laser of which amplitude modulation under the driving of current impulse, mid and far infrared laser collimates exiting parallel by tygon collimation focusing lens 4, parallel mid and far infrared laser is divided into reference path and detection light path through spectroscope 5, the mid and far infrared laser of reference path is detected by the pyroelectric sensor module 7 of reference path after chopper 6 is modulated, the mid and far infrared laser of detection light path is reflected by gold-plated corner cube mirror 8 through the motor vehicle exhaust emission region in traveling, mid and far infrared laser after reflection is through chopper 6, detected by the pyroelectric sensor module 7 of detection light path after tygon collimation focusing lens 4.The sine-wave signal components of detection the pyroelectric sensor module 7 of light path, the pyroelectric sensor module 7 of reference path and arbitrary-function generator 1 inputs respectively in lock-in amplifier 9 and carries out related calculation, and result is outputted to computing machine 10 by lock-in amplifier 9.Computing machine 10 does additive operation with reference to the related operation output valve of the related operation output valve of the pyroelectric sensor module 7 of light path and the pyroelectric sensor module 7 of detection light path, and the process of data and the analysis of spectrum are carried out to result of calculation, finally obtain the measurement result of vehicle exhaust.
Described spectroscope 5 is arranged on tygon collimation focusing lens 4 dead ahead, and to collimate the light of exiting parallel at 45 ° with tygon collimation focusing lens 4;
As shown in Figure 2, the voltage signal that arbitrary-function generator 1 produces is controlled by computing machine, and produces three kinds of signals respectively: rectangular pulse signal, sawtooth signal and sine wave signal; First, under rect.p. makes quantum cascade laser be operated in pulse condition, can ensure that the working temperature of laser instrument can not be too high like this; Secondly, sawtooth wave makes the output wavelength of quantum cascade laser be modulated, and the wavelength variation range of mid and far infrared that quantum cascade laser exports and the amplitude of square wave are directly proportional; Finally, the sinusoidal wave mid and far infrared laser to exporting carries out Sine Modulated, makes laser can detect its light intensity by the method for correlation detection, thus improves signal to noise ratio (S/N ratio) and the sensitivity of detection; Input current pulsed drive module 2 after arbitrary-function generator 1 inside is by these three kinds of Signal averaging, current impulse driver module 2 carrys out drive volume qc laser 3 by the current signal exported after Voltage to current transducer through ovennodulation, sine-wave signal components in superposed signal is input to the related operation that lock-in amplifier 9 carries out signal by arbitrary-function generator 1 while output superposed signal to current impulse driver module 2, and lock-in amplifier is connected to computing machine 10.
As shown in Figure 3, pyroelectric sensor module 7 comprises pyroelectric sensor 13, resistance 12, filter capacitor 11; 1 pin of pyroelectric sensor 13 connects one end of DC voltage VCC and filter capacitor 11 simultaneously, one end of 2 pin connecting resistances 12, the other end ground connection simultaneously of 3 pin and resistance 12, and the other end of filter capacitor 11 is connected with lock-in amplifier 9; AC signal input lock-in amplifier 9 after filtering after electric capacity 11, the sinusoidal ac signal that lock-in amplifier 9 exports simultaneously drives chopper 6 to rotate with certain frequency, and lock-in amplifier 9 is connected to computing machine 10; Tygon collimation focusing lens 4 and chopper 6 are placed on pyroelectric sensor module 7 dead ahead.
As shown in Figure 4, based on the remote vehicle emissions detection method of quantum cascade laser, comprise step 410 ~ 460, and step 410 ~ 460 are steps that spectroscopic data process is realized by mean filter, spectral line linear fitting, fuzzy algorithm and neural network algorithm etc.What lock-in amplifier exported is measure the original spectral data (step 410) obtained, the random noise (step 420) in original spectral data is removed according to the method for the frequency usage mean filter function of sawtooth wave in arbitrary-function generator, obtain the spectroscopic data of the different wave length under frequency sweep after filtering, this mean filter function adopts the cycle of sawtooth signal in composite signal to realize mean filter; First filtered spectroscopic data uses Fu Yite (Voigt) linear function matching (step 430), and fitting function adopts Fu Yite (Voigt) linear function to be described by formula 1.
Wherein,
Wherein:
γ
d--Gaussian linear function spectral width;
γ
c-Lorentz linear function spectral width;
Fu Yite linear function spectral width Δ v can be obtained simultaneously
v:
Wherein: Δ v
cit is the collision live width of spectral line; Δ v
dit is the doppler linewidth of spectral line;
Repeat to use for n time Fu Yite (Voigt) linear function to carry out matching, the spectral distribution data Φ of the different spectral line of n bar can be obtained
v(step 440).Most probable absorption line (step 450) can be drawn according to ambiguity function degree of membership determination methods, if the set that hypothesis measures the spectroscopic data of i-th spectral line obtained is U={u to any spectrum line data that matching obtains
i1, u
i2, u
i3... u
im, then the data acquisition in the standard spectral data storehouse of i-th spectral line is V={v
i1, v
i2, v
i3... v
im, wherein i is natural number, and i is less than or equal to m; M is natural number; Then calculate the coefficient of similarity of set U and set V:
If coefficient of similarity r
uv(i)>=λ
uvi () then corresponding spectral line is judged as absorption line, thus to obtain i-th spectral line be effective absorption line, wherein λ
uvi () is the level value demarcated in advance.Finally the artificial neural network of the spectroscopic data of effective absorption line input precondition and demarcation is processed, drawn the concentration Y of gas with various in vehicle exhaust by artificial neural networks
j(X) (step 460), wherein X={X
1, X
2..., X
iit is the spectroscopic data of effective absorption line.
As shown in Figure 5, level value λ in ambiguity function degree of membership determination methods
uvi the parameter calibration flow process of () and artificial neural network is as follows:
Start (step 510); Fixing gold-plated plane mirror, the angle of quantum cascade laser and pyroelectric detector and position (step 520); The position of fixing long path cell and heating arrangement (step 530); Under collection room temperature condition, the spectrum of pure air exports numerical value (step 540); By being mixed in varing proportions by clean gas thus simulating the vehicle exhaust under different operating mode, the kind of clean gas comprises CO, CO
2, NO, NO
2, NH
3and SO
2deng, in calibration process, the vehicle exhaust that different proportion is mixed into is filled with long path cell as gas (step 550) to be calibrated; Around long path cell around on heater coil to the air homogeneous heating in long path cell, air themperature in long path cell is changed along with the change of setting model, gathers the spectroscopic data output valve (step 560) under different temperatures; Can train according to spectroscopic data output valve and the actual melting concn of vehicle exhaust and obtain ambiguity function degree of membership level value λ
uvi () and artificial neural network parameter (step 570), obtain ambiguity function degree of membership level value λ according to the mean value of N different measuring result
uvi (), utilizes this data sample training of human artificial neural networks simultaneously; If the resultant error of demarcating is greater than 20%, then need again to demarcate, continue circulation and perform step 540 to step 570; Otherwise terminate calibration process (step 590).
Claims (1)
1., based on the remote vehicle emissions detection method of quantum cascade laser, it is characterized in that comprising the steps:
Step (1). the original spectral data that lock-in amplifier output measurement obtains is to computing machine (10);
Step (2). the random noise in original spectral data is removed according to the method for the frequency usage mean filter function of sawtooth wave in arbitrary-function generator, in concrete employing composite signal, the cycle of sawtooth signal realizes mean filter, obtains the spectroscopic data of the different wave length under frequency sweep after filtering;
Step (3). first filtered spectroscopic data uses the matching of Fu Yite (Voigt) linear function, and Fu Yite (Voigt) linear function that fitting function adopts is described by formula (1);
Wherein,
γ
d--Gaussian linear function spectral width;
γ
c-Lorentz linear function spectral width;
Fu Yite linear function spectral width Δ v can be obtained simultaneously
v:
Wherein: Δ
v cit is the collision live width of spectral line; Δ
v dit is the doppler linewidth of spectral line;
Step (4). use Fu Yite (Voigt) linear function to repeat n matching, the spectral distribution data Φ of the different spectral line of n bar can be obtained
v, according to ambiguity function degree of membership determination methods, most probable absorption line is shown to any spectrum line data that matching obtains, if the set of measuring the spectroscopic data of i-th spectral line obtained is U={
u i1,
u i2,
u i3,
u im, the set of the standard spectral data of i-th spectral line is V={ simultaneously
v i1,
v i2,
v i3,
v im, wherein i is natural number, and i is less than or equal to m; M is natural number; Then the coefficient of similarity r of set U and set V is calculated
uv (i):
If coefficient of similarity r
uv (i)>=λ
uv i () then corresponding spectral line is judged as absorption line, thus to obtain i-th spectral line be effective absorption line, wherein λ
uv i () is the level value demarcated in advance;
Step (5). finally the artificial neural network of the spectroscopic data of effective absorption line input precondition and demarcation is processed, drawn the concentration Y of gas with various in vehicle exhaust by artificial neural networks
j(X), wherein X={X
1, X
2..., X
iit is the spectroscopic data of effective absorption line;
Level value λ in ambiguity function degree of membership determination methods in described step (4), step (5)
uv i the parameter calibration flow process of () and artificial neural network is specific as follows:
The angle of (a) fixing gold-plated plane mirror, quantum cascade laser and pyroelectric detector and position; The position of fixing long path cell and heating arrangement; Under collection room temperature condition, the spectrum of pure air exports numerical value;
B the vehicle exhaust of simulation, by being mixed in varing proportions by clean gas thus vehicle exhaust under simulating different operating mode, is filled with long path cell as gas to be calibrated in calibration process by ();
The kind of described clean gas comprises CO, CO
2, NO, NO
2, NH
3and SO
2;
(c) around long path cell around on heater coil to the air homogeneous heating in long path cell, the air themperature in long path cell is changed along with the change of setting model, gathers the spectroscopic data output valve under different temperatures;
One end of described long path cell arranges gold-plated corner cube mirror, the pyroelectric sensor module of other end set amount qc laser and detection light path;
D (), according to the actual mixture ratio example of the vehicle exhaust of spectroscopic data output valve and simulation, training obtains ambiguity function degree of membership level value λ
uv i () and artificial neural network parameter, wherein obtain ambiguity function degree of membership level value λ according to the mean value of N different measuring result
uv i (), utilizes the actual mixture ratio example training of human artificial neural networks of the vehicle exhaust of spectroscopic data output valve and simulation simultaneously; If the resultant error of demarcating is greater than 20%, then need again to demarcate; Otherwise end calibration process.
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| DE102016209360A1 (en) | 2016-05-31 | 2017-11-30 | Continental Automotive Gmbh | Method, apparatus for operating a nitrogen oxide sensor, computer program and computer program product |
| CN106383097B (en) * | 2016-11-16 | 2024-01-19 | 大连中汇达科学仪器有限公司 | Remote sensing detection system and method for motor vehicle tail gas based on tunable laser |
| CN106769899A (en) * | 2016-12-30 | 2017-05-31 | 武汉六九传感科技有限公司 | A kind of NH3 laser analysis module |
| CN107085074B (en) * | 2017-04-19 | 2019-07-23 | 中国科学技术大学 | A method of classification monitoring motor-vehicle tail-gas |
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| CN110501305A (en) * | 2019-09-09 | 2019-11-26 | 安徽岩芯光电技术有限公司 | A kind of detection device and method of vehicle exhaust |
| CN110618102A (en) * | 2019-09-25 | 2019-12-27 | 成都太阳神鸟智能控制有限公司 | Gas detection method and device based on dispersion spectrum analysis and artificial intelligence |
| CN111220570A (en) * | 2020-01-19 | 2020-06-02 | 电子科技大学 | Infrared multi-gas detection system and gas detection method |
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| CN114414517B (en) * | 2021-12-17 | 2024-02-20 | 山东微感光电子有限公司 | Low-power-consumption intrinsic safety type laser carbon monoxide sensing control method and system |
| CN116972780B (en) * | 2023-09-25 | 2024-01-26 | 北京锐达仪表有限公司 | Three-dimensional scanning device with object table gas distribution measurement or object table temperature and gas distribution measurement function |
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