CN104865227A - Quantitative measurement apparatus for volume fraction of soot produced by combustion in optical engine cylinder - Google Patents

Abstract

The invention discloses a quantitative measurement apparatus for the volume fraction of soot produced by combustion in an optical engine cylinder. According to the invention, a standard light source with known radiation intensity is used for calibrating radiation intensity of an ICCD camera equipped with a double-imaging device so as to obtain the sensitive coefficient of the ICCD camera to radiation intensity of an illuminant; a Nd: YAG laser generates high-energy laser which forms disk laser after being shaped by a battery of lenses, the disk laser enters a combustion chamber of an optical engine, and soot is heated by the disk laser and forms an incandescent light signal; and the incandescent light signal passes through a quartz window at the top of a piston, is reflected by a reflective mirror and is then collected by the ICCD camera, an image acquisition system acquires the image data of the incandescent light signal at two wavelengths, and image processing is carried out so as to obtain two-dimensional quantitative results of the volume fraction of the soot whose tangent plane is penetrated by the disk laser. The measurement apparatus provided by the invention employs the double-imaging device to realize multi-point on-line calibration and quantitative measurement of the volume fraction of soot, has a simple structure, and omits a sensor and a data acquisition device used in a traditional single-point calibration system, thereby reducing cost.

Description

A kind of optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device

Technical field

The present invention relates to quantitatively measuring device field, particularly relate to a kind of optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device.

Background technology

Soot is one of main noxious products in combustion process of the internal-combustion engine, is also one of important sources of urban atmosphere haze pollution.In order to reduce the soot emissions of internal combustion engine, must further investigate the generation oxidation mechanism of soot, effective soot quantivative approach is the basis of further investigation, and therefore realizing the quantitative measurment of soot in combustion process of the internal-combustion engine has important theoretical and practical significance.

Laser induced incandescence method due to have noiseless, resolution is high, two-dimensional measurement and coming into one's own, its ultimate principle utilizes high energy pulse laser (nanosecond) in very short time that the carbon soot particles in flame is heated to carbon soot particles gasification temperature (about 4000K) from flame temperature (about 2000K), the carbon soot particles of high temperature gives off vehement light, according to blackbody radiation law, within the scope of suitable determined wavelength, compared to the carbon soot particles after heating, original Fire Radiation can be left in the basket, and vehement light signal strength can reflect soot concentration.

The soot volume fraction of laser induced incandescence method quantitative measurement combustion process of the internal-combustion engine is utilized to need to demarcate vehement light signal, the vehement smooth method of duochrome method Calibration of Laser induction is the new scaling method proposed in recent years, this scaling method adopted single-point calibration in the past, utilize any soot volume fraction of space in two vehement smooth regions of photomultiplier measurement, utilize an ICCD (Intensified Charge Coupled Device simultaneously, strengthen charge-coupled image sensor) signal in the whole Chi Guang district of cameras record, then the quantitative result of this point is mapped in the vehement smooth region of whole two dimension, thus the two-dimensional quantitative realizing soot is measured, measuring point due to single-point calibration is fixing, therefore the measurement of soot in stable state laminar flame is relatively applicable to, but the combustion process in internal combustion (IC) engine cylinder is subject to the impact of turbulent flow in intake swirl and cylinder, belong to unstable state turbulent flame, the single-point calibration method of this static measuring point is difficult to realize the vehement smooth calibration process of effective soot.

Summary of the invention

The invention provides a kind of optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device, the present invention adopts two imaging device to realize the on-line proving of soot vehement light signal multiple spot, and then utilize measurement mechanism to carry out the high resolving power quantitative measurment of in-cylinder combustion process soot, described below:

A kind of optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device, is made up of Nd:YAG laser instrument, lens combination, optical engine, two imaging device, standard sources, ICCD camera, image capturing system and digit pulse chronotron; Piston top quartz window and reflective mirror is provided with in described optical engine;

The described standard sources utilizing radiation intensity known carries out radiation intensity calibration to the described ICCD camera that described pair of imaging device is housed, and obtains described ICCD camera to the sensitivity coefficient of luminophor radiation intensity;

Described Nd:YAG laser instrument produces superlaser, and after described lens combination shaping, form sheet laser, described sheet laser enters the firing chamber of described optical engine, and soot is formed vehement light signal by described sheet LASER HEATING;

Described vehement light signal is through piston top quartz window, by described ICCD collected by camera after mirror reflection, described image capturing system obtains vehement light signal view data on two wavelengths, obtains the soot volume fraction two-dimensional quantitative result of described sheet laser through soot tangent plane through image procossing.

The engine fuel injection signal of described digit pulse chronotron recording optically engine, and trigger described ICCD camera and described Nd:YAG laser instrument;

Described ICCD camera shooting moment, described Nd:YAG laser instrument trigger instants and described optical engine ignition timing reach synchronous.

Described pair of imaging device comprises: the logical filter of 450nm band, the logical filter of 650nm band and reflective mirror group,

The autoluminescence of luminophor is each passed through described 450nm and is with logical filter and described 650nm to be with logical filter to reflect through described reflective mirror group, and described ICCD camera obtains the image of radiant light on two different wave lengths;

Described image capturing system obtains described ICCD camera to the sensitivity coefficient of luminophor radiation intensity by the ratio of the signal intensity and standard lamp radiation intensity that calculate the acquisition of described ICCD camera.

The beneficial effect of technical scheme provided by the invention is:

(1) multi-point calibration can be realized, avoid the deficiency that in traditional single-point calibration process, spot measurement position is fixing, be suitable for unstable state turbulent flame soot to measure, improve calibration point physical location and the corresponding precision of image in calibration process, reduce calibrated error.

(2) can be implemented in line to demarcate, calibration process and measuring process unite two into one, and avoid the deficiency that traditional calibration process is separated with measuring process, thus reduce the impact of boundary condition variation on calibration coefficient.

(3) compared to traditional caliberating device, this measurement mechanism structure is simple, eliminates sensor and the data collector of traditional calibration system, reduces cost.

(4) proving installation of this invention is simple to operate, requires to reduce to the structure of modification of optical engine.

Accompanying drawing explanation

Fig. 1 is optical engine soot quantitatively measuring device schematic diagram;

Fig. 2 is the calibration schematic diagram of ICCD camera to luminophor radiation intensity sensitivity coefficient;

Fig. 3 is structure and the imaging schematic diagram of two imaging device.

In accompanying drawing, the list of parts representated by each label is as follows:

1-optical engine; 2-lens combination;

3-Nd:YAG laser instrument; 4-sheet laser;

The two imaging device of 5-; 6-ICCD camera;

7-image capturing system; 8-digit pulse chronotron;

9-view data; 10-camera trigger pip;

11-engine fuel injection signal; 12-laser instrument trigger pip;

13-piston top quartz window; 14-reflective mirror;

15-lightray propagation direction; 16-standard sources;

The logical filter of 17-450nm band; The logical filter of 18-650nm band;

19-reflective mirror group.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below embodiment of the present invention is described further in detail.

A kind of optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device, see Fig. 1, Fig. 2 and Fig. 3, be made up of Nd:YAG laser instrument 3, lens combination 2, optical engine 1, two imaging device 5, standard sources 16, ICCD camera 6, image capturing system 7 and digit pulse chronotron 8.Piston top quartz window 13 and reflective mirror 14 is provided with in optical engine 1.

The standard sources 16 utilizing radiation intensity known carries out radiation intensity calibration to the ICCD camera 6 that two imaging device 5 is housed, and obtains the sensitivity coefficient coefficient of ICCD camera 6 pairs of luminophor radiation intensity.Nd:YAG laser instrument 3 produces superlaser, sheet laser 4 is formed after lens combination 2 shaping, sheet laser 4 enters the firing chamber of optical engine 1 also through the soot Production Regional in fuel combustion process, soot is added the vehement light signal of thermosetting by sheet laser 4, vehement light signal is through piston top quartz window 13 (propagating along the lightray propagation direction 15 in Fig. 1), gathered by the ICCD camera 6 that two imaging device 5 is housed after reflective mirror 14 reflects, image capturing system 7 obtains vehement light signal view data 9 on two wavelengths, through image procossing obtain sheet laser 4 pass the soot volume fraction two-dimensional quantitative result of soot tangent plane.

Wherein, the engine fuel injection signal 11 of digit pulse chronotron 8 recording optically engine 1, and trigger ICCD camera 6 and Nd:YAG laser instrument 3 (namely triggering ICCD camera 6 and Nd:YAG laser instrument 3 respectively by camera trigger pip 10, laser instrument trigger pip 12), make ICCD camera 6 take moment, Nd:YAG laser instrument 3 trigger instants and optical engine 1 ignition timing and reach synchronous.

Wherein, needed to calibrate ICCD camera 6 before the soot carrying out reality is quantitative, obtain ICCD camera 6 pairs of luminophor radiation intensity sensitivity coefficient η (λ) on two wavelengths, detailed process is as follows:

The standard sources 16 utilizing radiation intensity known produces radiant light, radiant light through piston top quartz window 13, through reflective mirror 14 reflect after the accordance with optical signal direction of propagation 15 propagate, gathered by the ICCD camera 6 that two imaging device 5 is housed, as shown in Figure 3, this pair of imaging device 5 comprises the image-forming principle of two imaging device 5: the logical filter 17 of 450nm band, the logical filter 18 of 650nm band and reflective mirror group 19.The autoluminescence of luminophor is each passed through the logical filter 17 of 450nm band and the logical filter 18 of 650nm band reflects through reflective mirror group 19, finally in ICCD camera 6, form two width images, thus achieve ICCD camera 6 single shot and obtain the object of radiant light at two different wave length epigraphs simultaneously, image capturing system 7 obtains view data 9.The sensitivity coefficient η (λ) of ICCD camera 6 pairs of luminophor radiation intensity can be obtained by the ratio of the signal intensity and standard lamp radiation intensity that calculate the acquisition of ICCD camera 6.

During practical application, optical engine 1 is in the rotating speed of 1200 revs/min by dynamometer machine towing astern, produce the engine fuel injection signal 11 of 10Hz, triggered digital pulse delay unit 8, digit pulse chronotron 8 at the enterprising line delay in the basis of engine fuel injection signal 11 to determine that corresponding engine crankshaft corner carries out the quantitative measurment of laser induced incandescence method, digit pulse chronotron 8 produces laser instrument trigger pip 12 and triggers Nd:YAG laser instrument 3, it is 532nm that Nd:YAG laser instrument 3 produces wavelength, single pulse energy is the pulse laser of 60mJ, laser scioptics group 2 carries out shaping, formation width is 40mm, thickness is the sheet laser 4 of 1mm, the soot Production Regional that sheet laser 4 enters into optical engine 1 firing chamber forms vehement light signal, vehement light signal reflects through reflective mirror 14, the accordance with optical signal direction of propagation 15 is propagated, now, the camera trigger pip 10 that produces digit pulse chronotron 8 triggers the ICCD camera 6 that two imaging device 5 is housed and completes image acquisition process, view data 9 is obtained by image capturing system 7.

Utilize two the vehement light images obtained, obtain two vehement light signal matrixes through image cropping, background elimination, pixel correspondence, utilize matrix computations to obtain temperature T and the soot volume fraction f of corresponding point soot respectively according to formula (1), (2) _v, suppose that soot particle is ball-type here, and in laser region, soot particle is heated properly.

$T=\frac{\mathrm{hc}}{k}(\frac{1}{{\mathrm{\λ}}_2}-\frac{1}{{\mathrm{\λ}}_1})/\ln \left(\frac{I_{\mathrm{LII}}\left({\mathrm{\λ}}_1\right)}{I_{\mathrm{LII}}\left({\mathrm{\λ}}_2\right)}\frac{\mathrm{\η}\left({\mathrm{\λ}}_2\right)}{\mathrm{\η}\left({\mathrm{\λ}}_1\right)}\frac{{{\mathrm{\λ}}_1}^6}{{{\mathrm{\λ}}_2}^6}\frac{E{\left(m\right)}_2}{E{\left(m\right)}_1}\right)---\left(1\right)$

$f_v=\frac{I_{\mathrm{LII}}\left({\mathrm{\λ}}_1\right)}{\mathrm{\η}\left({\mathrm{\λ}}_1\right){\mathrm{\ω}}_b\frac{12{\mathrm{\πc}}^{2}h}{{{\mathrm{\λ}}_1}^6}E\left(m\right){\left[\exp (\frac{\mathrm{hc}}{k{\mathrm{\λ}}_{1}T}-1)\right]}^{-1}}---\left(2\right)$

Wherein, h is Planck's constant; C is the light velocity; K is Boltzmann constant; λ ₁and λ ₂for determined wavelength, wherein λ ₁and λ ₂be respectively 450nm and 650nm; I _lII(λ ₁) and I _lII(λ ₂) be respectively vehement light signal in wavelength X ₁and λ ₂on signal value; η (λ ₁) and η (λ ₂) be respectively ICCD in wavelength X ₁and λ ₂on calibration factor; ω _bfor the thickness of sheet laser 4; E (m) is soot absorption function, gets E (m) here ₁=E (m) ₂=0.26.

The embodiment of the present invention is to the model of each device except doing specified otherwise, and the model of other devices does not limit, as long as can complete the device of above-mentioned functions.

It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (3)

1. an optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device, is made up of Nd:YAG laser instrument, lens combination, optical engine, two imaging device, standard sources, ICCD camera, image capturing system and digit pulse chronotron; It is characterized in that, utilize described pair of imaging device to realize the multiple spot on-line proving of soot volume fraction and quantitative measurment in engine cylinder;

The described standard sources utilizing radiation intensity known carries out radiation intensity calibration to the described ICCD camera that described pair of imaging device is housed, and obtains described ICCD camera to the sensitivity coefficient of luminophor radiation intensity;

Described Nd:YAG laser instrument produces superlaser, and after described lens combination shaping, form sheet laser, described sheet laser enters the firing chamber of described optical engine, and soot is formed vehement light signal by described sheet LASER HEATING;

Described vehement light signal is through piston top quartz window, by described ICCD collected by camera after mirror reflection, described image capturing system obtains vehement light signal view data on two wavelengths, obtains the soot volume fraction two-dimensional quantitative result of described sheet laser through soot tangent plane through image procossing.

2. a kind of optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device according to claim 1, is characterized in that,

The engine fuel injection signal of described digit pulse chronotron recording optically engine, and trigger described ICCD camera and described Nd:YAG laser instrument;

Described ICCD camera shooting moment, described Nd:YAG laser instrument trigger instants and described optical engine ignition timing reach synchronous.

3. a kind of optical engine in-cylinder combustion process soot volume fraction quantitatively measuring device according to claim 1, it is characterized in that, described pair of imaging device comprises: the logical filter of 450nm band, the logical filter of 650nm band and reflective mirror group,

The autoluminescence of luminophor is each passed through described 450nm and is with logical filter and described 650nm to be with logical filter to reflect through described reflective mirror group, and described ICCD camera obtains the image of radiant light on two different wave lengths;

Described image capturing system obtains described ICCD camera to the sensitivity coefficient of luminophor radiation intensity by the ratio of the signal intensity and standard lamp radiation intensity that calculate the acquisition of described ICCD camera.