JP5526973B2 - Filter evaluation method and evaluation apparatus - Google Patents

Description

The present invention relates to an evaluation method for evaluating the performance of a porous filter that collects carbonaceous particles contained in a gas by pores and the presence or absence of defects by passing the introduced gas , and the evaluation method. It relates to the evaluation device used.

  Since the exhaust gas from the diesel engine includes particulate matter (hereinafter referred to as “PM”), the exhaust gas from the diesel engine has a diesel particulate for removing PM. A filter (hereinafter sometimes referred to as “DPF”) is attached.

  A general DPF is a porous ceramic body. When exhaust gas from a diesel engine passes through the porous body, PM is collected by pores in the porous body. Therefore, when manufacturing the DPF, the pore diameter and pore diameter distribution of the porous body are highly controlled. However, no matter how highly controlled the pore size and pore size distribution, if a defect such as a crack or a crack occurs in the porous body, PM leaks to the outside through this defect. Therefore, the DPF is required to be inspected for defects.

  Conventionally, as a method and apparatus for detecting a defect in a DPF, a method and apparatus for detecting a defect in a DPF by introducing fine particles from one end face of the DPF and irradiating laser light parallel to the end face on the discharge side have been proposed. (For example, see Patent Documents 1 and 2). In any of these technologies, fine particles of water are introduced into the DPF, and the presence and position of the defect are detected by laser light reflected (scattered) by the fine particles discharged from the end face of the DPF through the defect. .

  However, although the laser beam has high directivity, a part of the laser beam is also irradiated to the end surface of the DPF. Therefore, in the above prior art, it is necessary to distinguish between the reflected light from the filter end face and the reflected light from the fine particles. Therefore, in the technique disclosed in Patent Document 1, longitudinal waves are generated near the end face of the filter, and fine particles are moved by vibrating the air. This is because the reflected light from the filter end face and the reflected light from the fine particles are discriminated based on whether or not the bright spot due to the reflected light moves. Therefore, the technique of Patent Document 1 requires a device that generates longitudinal waves and vibrates the air, and the configuration is complicated. In addition, since the reflected light including the movement of the bright spot is analyzed, the processing is complicated. In addition, since the fine particles leaked through the defect are moved, there is a possibility that the position of the defect is specified inaccurately.

  On the other hand, in the technique of Patent Document 2, a lattice-shaped antireflection member is arranged so as to cover the filter end face. This is because the antireflection member prevents the filter end face from being irradiated with laser light, and the reflected light from the fine particles that have passed through the antireflection member is detected. Therefore, in Patent Document 2, an antireflection member is necessary, and the configuration is complicated. In addition, since the antireflection member has a lattice shape, in addition to partially preventing the passage of fine particles, the laser light irradiation to the filter end surface and the reflected light from the filter end surface are completely prevented by the lattice member. It cannot be prevented. Therefore, it has been difficult to detect defects with high accuracy.

  The fine water particles introduced into the DPF by the techniques of Patent Document 1 and Patent Document 2 have a large diameter of 0.3 μm to 200 μm, preferably 1 μm to 10 μm. Therefore, it cannot be detected unless it is a large defect. On the other hand, the particle size of soot, which is the main component of PM, is about 30 to 80 nm, soot is formed by aggregation, or PM formed by adhering other components to soot. The average particle diameter is generally 100 nm or less. Therefore, even fine defects that cannot be detected by the above-mentioned size of water fine particles cause PM to leak out.

  Here, regarding the PM concentration in the exhaust gas from the diesel engine, a regulation value is set by law, but in recent years, this regulation value has become very strict, and DPF has a high PM collection performance. Is required. Therefore, PM leakage due to minute defects must be detected with high accuracy.

  In addition, in the DPF currently being implemented, there is still a problem of collection leakage that causes minute PM to pass through without causing defects, and further improvements are being made as legal regulations increase. Is strongly desired. In particular, the collection leakage of minute PM in the initial use of the DPF is regarded as a problem. Therefore, in order to evaluate the PM collection performance of the DPF with high accuracy, an evaluation method and an evaluation apparatus capable of detecting even a minute PM leakage are required.

Therefore, in view of the above circumstances, the present invention is an evaluation method and an evaluation device for a porous filter that collects carbonaceous particles contained in a gas by pores by allowing the introduced gas to pass through, even a tiny carbonaceous particles can be detected leak, the presence or absence of capturing current performance and defects filter, method for evaluating the precision and filter that can be evaluated easily, and, the evaluation An object of the present invention is to provide an evaluation apparatus using the method.

To solve the above problems, the evaluation method of the filter that written in the present invention, by passing the "introduced gas, the porous collecting the carbonaceous particles contained in the gas in the pores filter a rating method, prior to introducing the gas containing carbonaceous particles having a particle diameter 10nm~200nm the upstream end face of the notated filter, before notated filter downstream end face parallel to the linear or planar By irradiating with laser light , radiation light having a wavelength different from the wavelength of the laser light by induced red light emission is emitted from the carbonaceous particles contained in the gas exhausted from the downstream end face, and is used as radiation light. The position where the carbonaceous particles leaked in the filter is specified from the position where the emitted induced red-light emission is detected . " In the above configuration, “the laser beam irradiated to the downstream end face of the filter is linear, and the filter is rotated by a predetermined angle around the axial center line of the filter or the laser beam is irradiated and induced. Rotating a device that detects red heat emission by a predetermined angle to rotate the direction in which the laser light is irradiated around the axis of the filter by a predetermined angle, and irradiating the laser light to detect induced red heat emission By repeating, the position where the carbonaceous particles leaked out in the filter can be specified two-dimensionally ”. Or, “the laser light applied to the downstream end face of the filter is planar, and by detecting the induced red heat emission from the direction facing the downstream end face, the position where the carbonaceous particles leaked in the filter is determined. It can be “two-dimensionally specified”. Furthermore, it is possible to “detect a change with time of the intensity of induced red heat emission emitted as radiation light”.

  When the laser beam is irradiated to the carbonaceous particles, the carbonaceous particles are rapidly heated and emit radiation light by induced red heat emission. Therefore, the carbonaceous particles leaked from the DPF can be detected by detecting the radiation light. Moreover, the position where the carbonaceous particles leaked can be specified on the DPF from the position of the radiant light.

  In the above prior art (Patent Document 1 and Patent Document 2), the light reflected by the fine particles, that is, the irradiated laser light itself is detected. Therefore, the light reflected by the fine particles and the light reflected from the filter end face have the same wavelength. Therefore, in addition to requiring a complicated configuration for discriminating both, complete discrimination is difficult as described above. On the other hand, in the present invention, the object to be detected is induced red heat emission by carbonaceous particles, and the wavelength is different from the irradiated laser light. Thereby, even if a part of the laser light hits the end face of the filter and is reflected, the induced red-light emission of the carbonaceous particles and the reflected light of the laser light can be optically distinguished. Therefore, according to the present invention, carbonaceous particles can be easily detected with a simple configuration without requiring a special configuration for distinguishing from the reflected light from the filter end face.

  In addition, since the particle size of the carbonaceous particles is very small, it is possible to detect the presence of minute defects and the collection leakage of minute carbonaceous particles that occur without causing defects with high accuracy. .

  Here, the gas introduced into the upstream end face of the DPF is referred to as “gas containing carbonaceous particles having a particle size of 10 nm to 200 nm” because, as described above, if the introduced particle size is too large, a large defect of the DPF This is because it can only be detected. Moreover, the range of the particle diameter of PM in which trapping leakage is regarded as a problem in an actual DPF is a range as shown in FIG. 5, and this range can be covered if the particle diameter is 10 nm to 200 nm. is there. FIG. 5 shows the result of measuring the particle diameter and number of PM contained in the exhaust gas from the diesel engine with a honeycomb structure DPF of silicon carbide ceramics and measuring the particle size and number of PM contained in the gas discharged from the DPF. is there. Here, particularly, the change with time of the particle size distribution of PM in the initial use of the DPF is shown. In the measurement shown in FIG. 5, a conventional DPF that is desired to improve PM collection leakage in the initial use is used. In addition, the present inventors have confirmed that the induced red heat emission can be sufficiently detected if the particle size of the carbonaceous particles is at least 10 nm.

  In the prior art (Patent Document 1 and Patent Document 2), the laser beam to be irradiated must be visible light in order to visualize the reflected light from the fine particles. On the other hand, the induced red-light emission of the carbonaceous particles does not depend on the wavelength of the laser beam to be irradiated. Therefore, in this invention, the laser beam to irradiate is not limited to visible light, but has the advantage that the freedom degree of the laser light source which can be used is high.

  When irradiating a laser beam in a planar shape, the laser light is diffused into a planar shape using a lens to obtain a sheet light. Thereby, the distribution of the carbonaceous particles leaked from the DPF can be detected two-dimensionally.

  On the other hand, when the laser light is irradiated as a linear beam light, it is not necessary to have a high output as compared with the case where the laser light source is irradiated as the sheet light. When the laser light is irradiated linearly, the distribution of the carbonaceous particles leaked from the DPF can be grasped two-dimensionally by rotating the direction of laser light irradiation.

Evaluation device filter that written in the present invention, by passing the "introduced gas, an evaluation device filters porous collecting the carbonaceous particles contained in the gas in the pores, before irradiation and gas introduction device for introducing a gas containing carbonaceous particles having a particle diameter 10nm~200nm the upstream end face of the notated filter, a laser beam to the downstream side end surface parallel to the linear or planar front notated filter And a laser beam irradiation device for emitting radiation light having a wavelength different from the wavelength of the laser beam by induced red heat emission from the carbonaceous particles contained in the gas discharged from the downstream end surface, and emitting as radiation light And a detecting device for identifying a position where the carbonaceous particles leaked in the filter from the position where the induced red-light emission is detected. In the above configuration, “the laser beam irradiation device irradiates the downstream end surface of the filter with a linear laser beam, and rotates the filter around a center line of the filter by a predetermined angle, or A rotation device that rotates the laser light irradiation device and the detection device by a predetermined angle is further provided, and the detection device can two-dimensionally identify the position where the carbonaceous particles leaked in the filter. Or, “the laser beam irradiation device irradiates the downstream end surface of the filter with a planar laser beam, and the detection device detects the induced red-light emission from the direction facing the downstream end surface. The position where carbonaceous particles leak out in the filter is specified two-dimensionally ”. Furthermore, “the detection device can detect a change with time of the intensity of the induced red-hot light emitted as radiant light”.

  According to the evaluation apparatus having the above configuration, the PM collection performance of the DPF and the presence or absence of defects can be increased using the above evaluation method without requiring a special configuration for distinguishing from the reflected light from the filter end face. The accuracy can be evaluated.

  As described above, as an effect of the present invention, it is possible to detect leakage even with a minute PM, and it is possible to accurately and easily evaluate the PM collection performance of the DPF and the presence or absence of defects. An evaluation method and an evaluation apparatus using the evaluation method can be provided.

It is a schematic block diagram of the evaluation apparatus of DPF of one Embodiment of this invention. When the DPF-1 is not used and after being used under condition 1, the average value of the intensity of the excited red light emission at a predetermined time when the discharged gas is irradiated with the laser light is the position where the induced red light emission is detected. It is the graph shown by the relationship. It is the graph which showed the change with time passage of the detected excitation red-light emission intensity | strength regarding the gas discharged | emitted from DPF-1 after use in Condition 1 with the position where induced red-light emission was detected. It is the graph which showed the change with the time passage of the detected induced red heat emission about the gas discharged | emitted from DPF-F and DPF-V. It is a particle size distribution map of PM.

  Hereinafter, a DPF evaluation method according to an embodiment of the present invention (hereinafter simply referred to as “evaluation method”) and a DPF evaluation device 1 that uses the evaluation method (hereinafter simply referred to as “evaluation device 1”). Will be described.

  The evaluation method of the present embodiment introduces a gas containing carbonaceous particles having a particle diameter of 10 nm to 200 nm into the upstream end face of the DPF, and irradiates the laser light in a line parallel to the downstream end face of the DPF. The carbonaceous particles contained in the gas discharged from the downstream side end face are detected by emitting induced red heat at a wavelength different from the wavelength of the laser beam. The evaluation method of this embodiment irradiates linear laser light in a direction perpendicular to the axis of the DPF, and also induces induced red heat emission by rotating the direction of laser light by a predetermined angle around the axis. Is detected.

  As shown in FIG. 1, the evaluation device 1 includes a gas introduction device 10 that introduces a gas containing carbonaceous particles having a particle diameter of 10 nm to 200 nm into the upstream end surface 101 of the DPF 100, and a downstream end surface 102 of the DPF 100. The laser beam irradiation apparatus 20 that irradiates the laser beam L in parallel lines and the carbonaceous particles contained in the gas discharged from the downstream end face 102 are irradiated with the laser beam L and emitted from the laser beam L. And a detection device 30 that detects induced red-light emission having a wavelength different from the wavelength. In addition, the laser beam irradiation apparatus 20 irradiates the linear laser beam L in a direction that passes through the axis Z of the DPF 100 and is orthogonal to the axis Z. The evaluation device 1 further includes a rotation device (not shown) that rotates the DPF 100 about the axis Z.

  More specifically, the gas introduction device 10 includes a diesel engine 10a that generates a gas containing PM having a particle diameter of 10 nm to 200 nm, a gas supply pipe 10b that supplies gas from the diesel engine 10a to the DPF 100, and a gas supply pipe 10b. The gas pool part 10c which diffuses gas is comprised so that the gas supplied via may be introduced from the whole upstream end surface 101 of DPF100. A rotary joint portion 10d is provided between the gas pool portion 10c and the gas supply pipe 10b in order to rotate the DPF 100 without displacing the gas supply pipe 10b or the diesel engine 10a.

  Further, the detection device 30 of this embodiment mainly includes a CCD camera 31 and a computer 32. Here, the computer 32 analyzes the image data picked up by the CCD camera 31 and outputs the relationship between the intensity of the excitation red heat emission of PM and the position where the excitation red heat emission is detected, etc. as an output device such as a monitor or a printer. A program that causes the computer 32 to function as image analysis means for output to (not shown) is stored. On the other hand, the CCD camera 31 is installed with the imaging direction facing in a direction perpendicular to the irradiation direction of the laser light L and perpendicular to the axis Z of the DPF 100.

  With the above configuration, the gas discharged from the downstream end face 102 of the DPF 100 is irradiated with the laser light L, imaged by the CCD camera 31, and the obtained image data is analyzed, whereby the PM distribution leaked from the DPF 100 is It can be detected along the diameter in the cross section of the DPF 100. The PM distribution leaked from the DPF 100 is two-dimensionally repeated by repeating the process of rotating the DPF 100 around the axis Z and irradiating the laser beam L again and taking an image with the CCD camera 31. I can grasp it.

A DPF (hereinafter referred to as “DPF-1”) of a honeycomb structure of silicon carbide ceramics was produced using a mixed powder in which silicon carbide, silicon nitride, and carbon powders were blended in the following proportions as a raw material.
SiC (average particle diameter 12 μm) 75% by weight
Si ₃ N ₄ (average particle diameter 10 μm) 20% by weight
C (average particle diameter 15 μm) 5% by weight

  A specific method for producing DPF-1 is shown below. First, the raw material mixed powder was mixed and kneaded with methyl cellulose as an organic binder and water to obtain a kneaded product having a predetermined viscosity. This kneaded product is extruded, formed into a prismatic honeycomb structure with a plurality of cells extending in a single axial direction, dried, and then the ends of the cells are alternately sealed with the same composition. Stopped. The molded body was fired in a non-oxidizing atmosphere at 2300 ° C. The cell density was 300 cells / in 2 and the partition wall thickness was 0.25 mm. A plurality of the fired bodies were joined using an adhesive, and after drying, they were ground into a cylindrical shape having a diameter of 5.66 inches and a length of 6.00 inches. Further, the honeycomb structure obtained by applying the outer peripheral material to the outer peripheral surface and performing heat treatment was press-fitted into the casing in a state where the outer peripheral surface was covered with a protective material made of ceramic fibers to obtain a DPF.

  About DPF-1, when it is unused and after using it under severe conditions (hereinafter referred to as “condition 1”), it is arranged as DPF 100 in the evaluation device 1 described above, and the evaluation method described above Was evaluated. Here, as the laser beam irradiation apparatus 20, an apparatus using a second harmonic (wavelength: 532 nm) of an Nd: YAG laser as a light source was used.

  Condition 1 is a use condition as follows. DPF-1 is installed in the exhaust gas distribution route from the diesel engine (Nissan QD32 type, displacement 3163L), the diesel engine is operated under the operating conditions of engine speed 1400 rpm and torque 200 Nm, and 14 g / L of PM is obtained. Deposited in DPF-1. Next, a regeneration process for burning PM was performed by raising the engine speed to 3000 rpm and immediately setting the idling state when the temperature reached 680 ° C. The internal temperature during the regeneration process reached a high temperature of 1300 ° C.

  With respect to the unused DPF-1 and the DPF-1 after use in Condition 1, the laser light L is irradiated to the gas discharged from the respective downstream side end faces, and the CCD camera 31 emits one sheet every 0.5 seconds. Images were taken at a rate. The intensity of induced red-light emission was acquired from each imaged image data. FIG. 2 is a graph showing the average value of the induced red heat emission intensity for the first 50 seconds after the start of imaging in relation to the position (distance from the center of the DPF) where the induced red heat emission is detected.

  As apparent from FIG. 2, almost no induced red heat emission was detected in the exhaust from the unused DPF-1. From this result, it can be evaluated that PM in the exhaust gas from the diesel engine is collected in the DPF-1 and hardly leaked out. On the other hand, with respect to the exhaust from DPF-1 after use under condition 1, induced red-light emission was detected, and it was evaluated that a defect of a size that caused PM to leak due to use under severe conditions occurred inside the DPF. can do.

  Further, the intensity of the induced red-light emission is proportional to the volume fraction of PM. That is, the greater the PM particle size and the higher the PM particle concentration, the greater the intensity of the induced red light emission, so the intensity distribution of the induced red heat light emission can be considered as the volume distribution of the leaked PM. it can. Then, by rotating the DPF-1 around the axis Z and performing the above processing a plurality of times, and obtaining the distribution as shown in FIG. 2 for each, it is possible to obtain a two-dimensional distribution by combining them. it can.

  Next, FIG. 3 shows a relationship between the detected change in the induced red light emission over time and the position where the induced red heat emission is detected for the gas discharged from the DPF-1 after use in Condition 1. Here, the average value of the first 50 seconds (0 to 50 seconds) after the start of imaging, 100 seconds, from the intensity of the induced red heat emission obtained from the image data captured at a rate of one image per 0.5 seconds. The average value of ˜150 seconds and the average value of 200 seconds to 250 seconds are calculated and the results are shown.

  From FIG. 3, it can be seen that the PM leaking from the DPF decreases with time, that is, a defect once generated in the DPF is blocked by the PM introduced and collected in the DPF. You can see that it is coming off. In other words, according to the evaluation method and the evaluation apparatus of the present embodiment, it can be seen that even the minute defect that is blocked by the collection of PM can be detected.

Next, according to the evaluation method and the evaluation apparatus of the present embodiment, in order to show that it is possible to evaluate the collection leakage of a minute PM that is not caused by a defect, two types of DPFs (hereinafter referred to as "different apparent porosity") The result examined using "DPF-F" and "DPF-V") is shown. The apparent porosity and average pore diameter of each of DPF-F and DPF-V are shown below.
DPF-F: apparent porosity 42%, average pore diameter 12 μm
DPF-V: apparent porosity 58%, average pore diameter 20 μm

  Here, the average pore diameter was determined as a re-frequency diameter (diameter) from a pore diameter distribution measured by a mercury intrusion method using a mercury porosimeter (manufactured by Micromeritics, Autopore IV9500). The apparent porosity was calculated from the volume of mercury pressed into the sample and the sample volume when measuring the average pore diameter by the mercury intrusion method.

  Here, DPF-F was manufactured by the same manufacturing method as DPF-1 described above except that the cell density was 100 cells / in 2 and the partition wall thickness was 0.4 mm.

On the other hand, DPF-V was produced using a mixed powder in which silicon carbide, silicon nitride, and carbon powders were blended at the following ratio as a raw material.
SiC (average particle diameter 9.5 μm) 50% by weight
Si ₃ N ₄ (average particle diameter 10 μm) 40% by weight
C (average particle diameter 15 μm) 10% by weight

  The manufacturing method of DPF-V is shown below. First, the raw material mixed powder was mixed and kneaded with methyl cellulose as an organic binder, water, and starch as a pore-forming agent to obtain a kneaded product having a predetermined viscosity. This kneaded product was formed into a prismatic honeycomb structure by extrusion and dried, and then the cell ends were alternately sealed with the kneaded product having the same composition. The molded body was fired in a non-oxidizing atmosphere at 2300 ° C. The cell density was 225 cells / in 2 and the partition wall thickness was 0.4 mm. A plurality of the fired bodies were joined using an adhesive, and after drying, they were ground into a cylindrical shape having a diameter of 5.66 inches and a length of 6.00 inches. Further, the honeycomb structure obtained by applying the outer peripheral material to the outer peripheral surface and performing heat treatment was press-fitted into the casing in a state where the outer peripheral surface was covered with a protective material made of ceramic fibers to obtain a DPF.

  FIG. 4 shows changes with time of the detected induced red heat emission for the gases discharged from the DPF-F and DPF-V. Here, the results of integrating the intensity of the induced red heat emission over the entire length of the linear laser light from the image data captured at a rate of one image per 0.5 second are plotted with the passage of time. In the figure, the alternate long and short dash line T1 is when the engine is started, and T2 is when the engine is stopped.

  As apparent from FIG. 4, when comparing DPF-F and DPF-V, the intensity of the induced red-light emission in the initial stage of use for about 3 minutes after the start of the engine is lower in DPF-F. That is, PM collection leakage in the initial stage of use is less in DPF-F having a low apparent porosity and a smaller average pore diameter than DPF-V having a high apparent porosity and a large average pore diameter. In the DPF-F, the PM collection leakage is rapidly reduced within about 60 seconds after the engine is started, and there is almost no collection leakage. For this reason, in the DPF-F, although a slight PM collection leakage is observed in the initial stage of use, a PM layer is formed very early by the PM collected immediately after the start of use. It is thought that PM to be collected is collected effectively.

  On the other hand, in the DPF-V having a high apparent porosity and a large average pore diameter, there are many PM collection leaks in the initial stage of use. And the PM collection leakage gradually decreases with the passage of time, but even after 3 minutes from the start of the engine, the intensity of the induced red light emission has not decreased to the value at the start of the engine, There is a slight PM leakage. From this, it can be seen that the time until the PM layer is formed by the PM collected earlier and the filtering action is performed on the PM flowing later varies depending on the apparent porosity and average pore diameter of the DPF. That is, according to the evaluation method and the evaluation apparatus of the present embodiment, fine PM collection leakage not caused by defects, in particular, PM collection leakage in the initial stage of use and the formation rate of the PM layer are evaluated with high accuracy. It is possible.

  As described above, according to the present embodiment, a simple evaluation method and an evaluation apparatus that irradiates the gas discharged from the DPF with laser light and detects the induced red heat emission emitted from the PM via the CCD camera. The presence or absence of a defect in the DPF, the position of the defect, and the minute PM leakage that is not caused by the defect can be detected with high accuracy.

  Further, since the laser beam is irradiated as a linear beam, it is not necessary to increase the output of the laser beam, and the evaluation apparatus can be configured with a simple laser beam irradiation device. Further, since the laser beam is linear, it is possible to take an image from a direction orthogonal to both the irradiation direction of the laser beam and the axis of the DPF. Thereby, there is an advantage that the lens of the CCD camera does not face the downstream end surface of the DPF, that is, the surface from which the gas containing PM is discharged and is not easily contaminated.

  In addition, since the evaluation apparatus of the present embodiment includes means for rotating the DPF, even if the laser beam is linear, by rotating the DPF, the leaked PM distribution can be two-dimensionally distributed. It is possible to grasp.

  The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention as described below. And design changes are possible.

  For example, in the evaluation apparatus described above, the configuration in which the DPF is rotated around the axis line in order to change the angle at which the linear laser beam is applied to the DPF is illustrated. The laser beam irradiation device and the CCD camera may be rotated around the axis of the DPF without rotating.

  In the evaluation method and the evaluation apparatus described above, the case where the laser beam is irradiated linearly is exemplified, but the laser beam can also be irradiated in a planar shape. For example, by using two cylindrical lenses, or a combination of a cylindrical lens and a convex lens, linear laser light can be expanded in a planar shape. By making the laser beam planar, it is possible to two-dimensionally detect the PM distribution leaked from the DPF without rotating the DPF or displacing the laser beam irradiation device and the detection device. it can. In this case, it is desirable that the imaging direction by the CCD camera is a direction facing the surface irradiated with the laser light. Therefore, it is desirable to cover the front of the camera lens with a highly transparent protective material such as quartz glass in order to prevent contamination of the camera lens with gas containing PM.

  Furthermore, the detection accuracy of excitation red heat emission can be further improved by a simple means for attaching a filter for selectively detecting the wavelength of excitation red heat emission to the lens of the CCD camera. For example, a bandpass filter having a transmission center wavelength of 450 nm and a half width of 50 nm can be attached to the lens of the CCD camera.

1 evaluation device (evaluation apparatus of the filter)
10 Gas introduction device 10a Diesel engine (gas introduction device)
10b Gas supply pipe (gas introduction device)
10c Gas pool section (gas introduction device)
10d Rotary joint (gas introduction device)
20 Laser beam irradiation device 30 Detection device 31 CCD camera (detection device)
32 Computer (detection device)

JP 2009-115655 A JP 2009-92480 A

Claims (8)

An evaluation method of a porous filter that collects carbonaceous particles contained in a gas by pores by passing an introduced gas,
Introducing a gas containing carbonaceous particles having a particle diameter 10nm~200nm the upstream end face of the front notated filter,
By applying a laser beam to the downstream side end surface parallel to the linear or planar front notated filter, from the carbonaceous particles contained in the gas discharged from the downstream end face, the laser according to the induced glow emission Emitting radiation light having a wavelength different from the wavelength of light, and identifying a position where carbonaceous particles have leaked in the filter from a position where induced red light emission emitted as radiation light is detected. evaluation method of be that filter with. Laser light applied to the downstream end face of the filter is linear, and the filter is rotated by a predetermined angle around the axial center line of the filter, or an apparatus that irradiates the laser light and induced red-light emission is detected. By rotating the device by a predetermined angle, the direction in which the laser beam is irradiated is rotated by a predetermined angle around the axis of the filter, and the process of detecting the induced red heat emission by irradiating the laser beam is repeated. The method for evaluating a filter according to claim 1 , characterized in that a position where carbonaceous particles leak in the filter is specified two-dimensionally . The laser beam applied to the downstream end face of the filter is planar, and the position where the carbonaceous particles leaked in the filter is two-dimensionally detected by detecting induced red light emission from the direction facing the downstream end face. Specific to
The filter evaluation method according to claim 1. Detects changes in the intensity of the induced red-light emission emitted as radiant light over time
The method for evaluating a filter according to any one of claims 1 to 3, wherein: An evaluation device for a porous filter that collects carbonaceous particles contained in a gas by pores by passing an introduced gas,
A gas introduction device for introducing a gas containing carbonaceous particles having a particle diameter of 10 nm to 200 nm on the upstream end face of the filter;
The laser beam is irradiated in a linear or planar manner parallel to the downstream end face of the filter, and the wavelength of the laser light by induced red heat emission from the carbonaceous particles contained in the gas discharged from the downstream end face Is a laser beam irradiation device that emits radiation light of different wavelengths;
A detection device for identifying a position where carbonaceous particles leaked in the filter from a position where induced red-light emission emitted as radiant light is detected;
An apparatus for evaluating a filter, comprising: The laser beam irradiation device irradiates the downstream end surface of the filter with a linear laser beam,
A rotation device that rotates the filter by a predetermined angle around the axis of the filter, or rotates the laser light irradiation device and the detection device by a predetermined angle;
The detection device two-dimensionally identifies a position where carbonaceous particles leak out in the filter.
The filter evaluation apparatus according to claim 5. The laser beam irradiation device irradiates the downstream end surface of the filter with a planar laser beam,
The detection device two-dimensionally identifies the position where the carbonaceous particles have leaked in the filter by detecting the induced red heat emission from the direction facing the downstream end surface.
The filter evaluation apparatus according to claim 5. The detection device detects a change with time of the intensity of the induced red heat emission emitted as radiation light.
The filter evaluation apparatus according to claim 5, wherein the filter evaluation apparatus is a filter.

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