JP2003056332A - Exhaust fine particle measuring instrument and exhaust fine particle measuring method with usage of it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust fine particle measuring instrument and an exhaust fine particle measuring method with the usage of it capable of continuously measuring an amount of exhaust fine particles contained in an exhaust gas and capable of accurately measuring the amount of the exhaust fine particles in the exhaust gas by burning and removing the exhaust fine particles accumulated on a part of the measuring device brought into contact with the exhaust gas. SOLUTION: This exhaust fine particle measuring instrument is constituted by a heat resistant metallic case body 1, a treatment chamber 5 provided in the case body 1 and having an inlet port 6 and an exhaust port 7 communicating to an outside, a heat resistant metallic resistance heating type filter element 9 attached on an inside surface through a heat resistant insulating layer 8 at a position between the inlet port 6 and the exhaust port 7 inside the treatment chamber 5, a current supply control means 11 for supplying current to the resistance heating type filter element 9 so that resistance heating may be performed, and a resistance measuring means 13 for measuring electric resistance or electric conductivity between the case body 1 and the resistance heating type filter element 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust fine particle removing device for capturing exhaust fine particles contained in exhaust gas emitted from a diesel engine or the like, and operating the exhaust fine particle removing device for combustion removal. Installed in the exhaust gas flow path before and after, measure the content of exhaust particulates in each exhaust gas, or from the measured value of the content of exhaust particulates in the exhaust gas before passing through the exhaust particulate removal device Exhaust particulate measuring apparatus and exhaust particulate measuring method using the same, which indirectly detect the amount of exhaust particulate captured by the filter element of the exhaust particulate removing apparatus and can be used for timing setting of combustion removal Regarding

[0002]

2. Description of the Related Art As a method for measuring the content of exhaust particulates in exhaust gas, for example, a portion of the exhaust gas collected from an exhaust gas passage is passed through a detection filter and the exhaust particulates collected by the filter are collected. That weighs the weight of the exhaust gas, a part of the exhaust gas separated from the exhaust gas passage through a detection filter and a pressure difference between the upstream side and the downstream side of the filter, and exhaust particulates in the exhaust gas passage. A device for measuring the differential pressure between the upstream side and the downstream side of the filter provided with a removal filter, or a light projecting element and a light receiving element are arranged to face each other across the exhaust gas flow path, and the light projecting element to the light receiving element There are already known devices for measuring the light transmittance of the above.

However, in the above-mentioned prior art,
The measurement method that weighs the weight of the exhaust particulates collected by the filter is a reliable measurement method that is also adopted in the Japanese Industrial Standards, but since it is a batch process, the time delay of the measurement results cannot be avoided. Therefore, it is difficult to use this measuring method for the timing setting of the combustion removal of the filter element in the exhaust particulate removal device. In addition, in the method for measuring the content of exhaust particulates according to the related art other than the above, continuous measurement is possible, but the exhaust particulates are deposited and adhered with time to a part of the measuring device in contact with the exhaust gas. There was a problem that accurate measurement was hindered.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to enable continuous measurement of the content of exhaust particulates in exhaust gas, and to burn and remove exhaust particulates deposited on a part of the measuring device in contact with exhaust gas. An object is to provide an exhaust particulate measuring apparatus and an exhaust particulate measuring method using the same, which enables accurate and accurate measurement.

[0005]

An exhaust particle measuring apparatus according to the present invention comprises a case body made of a heat-resistant metal, and a processing chamber having an intake port and an exhaust port which are provided inside the case body and communicate with the outside. A resistance heating type filter element made of a heat-resistant metal, which is loaded in the processing chamber at a position between the intake port and the exhaust port via a heat-resistant electric insulating layer between the inner surface and the inside, and a resistance heating type. And a resistance measuring means for measuring electric resistance or electric conductivity between the case body and the resistance heating type filter element. .

Further, an exhaust particulate measuring method according to the present invention is a measuring method using the above exhaust particulate measuring apparatus, in which the case body has an exhaust port of the exhaust gas flow passage which is closer to the exhaust gas passage than the intake port. Arranged in the exhaust gas flow path so as to communicate with the high flow rate side, the exhaust port side is decompressed from the intake port side,
As a result, part of the exhaust gas is taken in from the intake port of the processing chamber and discharged from the exhaust port through the resistance heating type filter element, and the case body and the resistance heating type filter element are measured by the resistance measuring means. The electrical resistance or electrical conductivity between and is measured over time, thereby indirectly measuring the amount of exhaust particulates deposited so as to bridge the electrical insulating layer between the inner surface of the processing chamber and the resistance heating filter element. In the state of detecting and passing a part of the exhaust gas through the resistance heating type filter element, the energization control means energizes the resistance heating type filter element to resistance heat it and capture it in the resistance heating type filter element. The exhaust particulates are burned, and the exhaust particulates accumulated between the side surface of the processing chamber and the resistance heating type filter element and other parts inside the processing chamber are also burned. It is made of regenerating a resistive heating type filter element by burnt.

In the above structure, the exhaust port of the processing chamber communicating with the higher flow velocity side of the exhaust gas flow passage, usually with respect to the central side of the exhaust gas flow passage, has a lower flow velocity side, usually with respect to the exhaust gas flow passage. The pressure is lower than that of the intake port of the processing chamber communicating with the end side, so that part of the exhaust gas in the exhaust gas flow path flows from the intake port toward the exhaust port.

As described above, the exhaust gas taken in from the intake port of the processing chamber is exhausted from the exhaust port through the resistance heating type filter element, while exhaust particulates in the exhaust gas are resistively heated. Type filter element and also trapped between the side surface of the processing chamber and the resistance heating type filter element and at other places inside the processing chamber, and are sequentially deposited.

Since the electric insulating layer is interposed between the side surface of the processing chamber and the resistance heating type filter element, before the operation of the exhaust particulate measuring apparatus, the case body and the resistance heating can be measured even if the measurement is made by the resistance measuring means. No conductivity is detected with the mold filter element. For the electrically insulating layer, for example, a breathable porous inorganic fiber or a heat resistant filter such as a ceramic particle layer, as well as a breathable or non-breathable ceramic ring or ceramic tube may be used.

Since the exhaust fine particles contain a large amount of conductive material composed of carbon particles, the exhaust fine particles are trapped between the inside surface of the processing chamber and the resistance heating type filter element, and as they are deposited, the case body and the resistance heating type At the same time as the electrical resistance with the filter element decreases, the electrical conductivity also increases, which is detected by a measuring means such as resistance. That is, in the exhaust particulate matter measuring apparatus and method according to the present invention, since the exhaust particulates contain a large amount of conductive material such as carbon particles, the exhaust particulates trapped between the case body and the resistance heating type filter element are accumulated. It utilizes the fact that the electrical resistance between them decreases as the amount increases. As described above, the exhaust particulates that reduce the electric resistance between the case body and the resistance heating type filter element are compared to the entrance side of the resistance heating type filter element, and the surface of the electric insulating layer adjacent to the entrance side and the side surface inside the processing chamber. When the electrically insulating layer is made of, for example, a breathable heat resistant filter, it is also deposited inside the heat resistant filter.

Therefore, for example, the time-dependent pattern of the measured value of the electric resistance or the electric conductivity measured by the resistance measuring means for each exhaust gas discharge condition, that is, the operating condition of the engine and the exhaust particulate matter in the exhaust gas at that time. By recording a large number of actual content data in advance, the content of exhaust particulates in the exhaust gas at that time can be determined from the temporal pattern of measured values of electrical resistance or electrical conductivity measured under the same operating conditions. It becomes possible to know.

After the time-dependent pattern of the measured value of the electric resistance or the electric conductivity by the measuring means such as the resistance is measured as described above, the resistance heating type filter element is energized in a state in which a certain amount or more of exhaust particulates are trapped. When the resistance heating type filter element is energized by the control means, the resistance heating type filter element is resistance heated and at the same time, the exhaust particulates mainly composed of carbon particles and high molecular hydrocarbon substances are oxygen in the exhaust gas. Burned away by the heat of combustion,
Furthermore, exhaust particulate matter accumulated between the side surface of the processing chamber and the resistance heating type filter element and other portions inside the processing chamber are also burned and removed in a chained manner, whereby the resistance heating type filter element is completely reusable and regenerated. Will be done.
In the above case, the oxygen required for combustion of the exhaust particulates is supplied from the exhaust gas itself passing through the resistance heating type filter element, so that a pipe or valve for supplying oxygen is not particularly required. Whether or not the regeneration operation of the resistance heating type filter element is normally completed can be easily known from the measured value of the electric resistance or the electric conductivity by the measuring means such as the resistance.

When the resistance heating type filter element is resistance-heated during the regeneration of the resistance heating type filter element, the volume expansion and the viscosity increase of the exhaust gas passing through the resistance heating type filter element occur, and the resistance increases in combination with the accumulation of exhaust particulates. As the ventilation resistance of the heating type filter element increases, the ventilation volume of the exhaust gas automatically decreases, thereby resistance heating under the condition that oxygen supply from exhaust gas required for combustion of exhaust particulate is reserved. The heating and ignition of exhaust particulates by the mold filter element are promoted. A small capacity battery is sufficient for the energization by the energization control means.

In order to attach the exhaust particulate matter measuring device to the measurement site, the outer surface of the case body may be threaded so as to be screwed into the wall body of the measurement site. Examples of the resistance heating type filter element include, for example, Japanese Patent Laid-Open No. 9-245938.
As disclosed in Japanese Patent Application Laid-Open No. 11-257048 and Japanese Patent Application Laid-Open No. 11-257048, porous metal sheets are laminated in multiple layers, and a porous electrical insulating film is interposed between opposed surfaces of the laminated porous metal sheets, In addition, the porous metal sheet is formed by corrugating or corrugating the metal sheet material at the same time, and at the same time, forming a large number of through-holes having break-like protrusions on the periphery of the corrugated or corrugated peaks and / or valleys. It is possible to preferably employ the one formed by drilling in.

According to the constitution of the resistance heating type filter element, the corrugated or concavo-convex peaks and troughs are formed between the facing surfaces of the laminated porous metal sheets, and the peripheral edges of the corrugated perforations are formed. Since a complicatedly bent flow path space is formed by a through hole having a fracture-like projection, the exhaust gas flowing between the facing surfaces is complicatedly diffused and collided inside the flow path space, and exhaust gas is exhausted in the meantime. Exhaust particulates in the gas are effectively trapped on the porous metal sheet. In the case where the porous electric insulating film interposed between the facing surfaces of the laminated porous metal sheets has a filter function, exhaust particulates are also captured in the porous electric insulating film.

In the resistance heating type filter element, the ventilation resistance and the trapping ability of exhaust particulates are selected by selecting the laminating mode of the porous metal sheets constituting the filter element, the size of the through holes having the broken projections, the formation density and the like. It can be changed individually,
For example, the trapping ability of the resistance heating type filter element near the exhaust gas discharge side may be strengthened than that of the resistance heating type filter element near the exhaust gas introduction side.

The resistance heating type filter element is, for example,
A porous metal sheet may be laminated in a spiral shape with a porous electric insulating film interposed therebetween so that it can be easily loaded into the columnar processing chamber. Also, it can be easily loaded into the rectangular column processing chamber. Alternatively, it may be formed by stacking porous metal sheets in a zigzag shape with a porous electric insulating film interposed therebetween. Heat resistant stainless steel can be preferably used for the porous metal sheet. Further, the porous electrical insulating film is for preventing electrical contact between the facing surfaces of the laminated porous metal sheets during electric heating, and even an insulating coating formed on the surface of the porous metal sheet. It is good, but it is preferable to use a material having a function of filtering exhaust particulates, such as heat-resistant inorganic fiber. Further, the porous metal sheet and / or the porous electric insulating film in each of the resistance heating type filter elements may be caused to carry an oxidation catalyst through a necessary carrying layer, if necessary. The exhaust particulates captured by each resistance heating type filter element can be burned more effectively and at a relatively low temperature.

[0018]

1 is a sectional view of an essential part of an exhaust particle measuring apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view of a resistance heating type filter element used in the exhaust particle measuring apparatus shown in FIG. It is a figure. FIG. 3 is a block diagram illustrating a circuit configuration of an exhaust particulate matter measuring apparatus according to an embodiment of the present invention.

In FIG. 1, a case body 1 made of a heat-resistant metal in the form of a bolt is screwed in a hermetically sealed manner by its screw portion 2 so as to project from an outer surface of a wall of an exhaust gas pipe 3 into an internal exhaust gas passage 4. Has been done. A cylindrical processing chamber 5 is formed inside the case body 1 in the axial direction from the end of the case body 1.
The exhaust gas passage 4 is provided with a plurality of intake ports 6 that communicate with each other in the radial direction, and an exhaust port 7 that communicates with the center of the exhaust gas passage 4 in the axial direction.

A resistance heating type filter element 9 made of a heat-resistant metal is loaded inside the processing chamber 5 at a position between the intake port 6 and the exhaust port 7 via an electric insulating layer 8 between the inner surface and the inside. Has been done.

In the resistance heating type filter element 9, from the energization control means 11 installed outside the exhaust gas pipe 3 to the case body 1.
Is electrically insulated and an electric wiring 12 is provided so that the resistance heating type filter element 9 can be resistance heated by the energization from the energization control means 11. Further, one of the case body 1 and the electric wiring 12 is provided with another electric wiring 14 from a resistance measuring means 13 installed outside the exhaust gas pipe 3, and the case body 1 and the resistance heating type filter element 9 are provided. The electrical resistance or the electrical conductivity between the two can be measured by the operation of the resistance measuring means 13. As the electric insulating layer 8, for example, a breathable heat-resistant filter which is filled with ceramic particles and capable of capturing exhaust particulates is used.

Further, the resistance heating type filter element 9 is
As shown in FIG. 2, the porous metal sheets 21 are spirally stacked in multiple layers and the porous metal sheets 21 are stacked.
A porous electric insulating film 22 is interposed between the opposing surfaces of
In addition, the porous metal sheet 21 is formed by corrugating or corrugating the metal sheet material at the same time as forming a large number of through holes 24 each having a broken protrusion 23 on the periphery thereof and / or the corrugated or corrugated peaks and / or Or while drilling in the valley,
The electric wiring 12 is provided on the porous metal sheet 21 so as to be capable of resistance heating by energization. The resistance heating type filter element 9 is oriented so that the exhaust gas passes in the spiral axis direction from one end side to the other end side between the facing surfaces of the laminated porous metal sheets 21 inside the case body 1. Has been.

In the above structure, the exhaust gas taken into the processing chamber 5 through the intake port 6 due to the pressure difference between the intake port 6 and the exhaust port 7 of the processing chamber 5 is the resistance heating type filter element 9
And is discharged from the exhaust port 7 through the exhaust gas, and during that time, exhaust particulates in the exhaust gas are captured by the resistance heating type filter element 9 and an electrical insulating layer between the inner surface of the processing chamber 5 and the resistance heating type filter element 9. 8 is also captured on the surface and inside and other places inside the processing chamber 5, and is sequentially deposited. As the exhaust particulates are deposited between the inner surface of the processing chamber 5 and the resistance heating filter element 9 so as to bridge them, the electrical resistance between the case body 1 and the resistance heating filter element 9 decreases. At the same time, the electrical conductivity increases.

The time-dependent measured value of the electric resistance measured by the resistance measuring means 13 is input to the difference circuit 31 as an example, as shown in FIG. In the difference circuit 31, according to the clock signal from the sample clock generator 32, the resistance measurement value R1 at the time T1 is sampled by the sample hold amplifier S / H ¹ 33, while the sample hold amplifier S / H ² 34 collects the resistance measurement value R1. A certain time ΔT from T1,
For example, the resistance measurement value R2 at the time T2 after only one second has elapsed is collected, and the difference ΔR between the two measurement values is calculated by the operational amplifier 35.
Is calculated and output. The difference circuit 3
It is also possible to use a differentiating circuit instead of 1.

The decrease amount ΔR / ΔT of the electric resistance output from the operational amplifier 35 is the exhaust particulate matter accumulated between the inner surface of the processing chamber 5 and the resistance heating type filter element 9 from the time T1 to the time T2. Of the exhaust gas particulate matter captured by the resistance heating type filter element 9 within the time period and the passage of the exhaust gas particulate matter passing through the exhaust gas passage 4 within the time period. It also correlates with quantity. The correlation coefficient in each of the above cases can be obtained in advance from the ratio of the reduction amount ΔR / ΔT of the electric resistance to the actual measurement value of the increase amount of the exhaust particulates and the passage amount of the exhaust particulates within that time. Is. The integral of the increase amount of the exhaust particulates and the passage amount of the exhaust particulates over a predetermined time represents the sum of the increase amount and the passing amount within the time.

When the resistance measurement value 13 indicating the state in which the set amount of exhaust particulate matter is trapped in the resistance heating type filter element 9 is detected by the resistance measuring means 13, the energization control means 11
When the resistance heating type filter element 9 is energized by, the resistance heating type filter element 9 is resistance-heated and the exhaust particulates trapped therein are burned and removed by the oxygen in the exhaust gas, and further processed by the combustion heat. Exhaust particulates accumulated between the inner surface of the chamber 5 and the resistance heating filter element 9 and at other locations inside the processing chamber 5 are also burned off in a chain manner, thereby making the resistance heating filter element 9 reusable. It will be completely reproduced.

[0027]

The exhaust particulate matter measuring apparatus and the exhaust particulate matter measuring method using the same according to the present invention are configured as described above, so that the content of exhaust particulate matter in exhaust gas can be continuously measured. Exhaust particulates deposited on a part of the measuring device in contact with the exhaust gas can be burned and removed for accurate measurement.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of an exhaust particulate matter measurement device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a resistance heating type filter element used in the exhaust particulate matter measurement device shown in FIG.

FIG. 3 is a block diagram illustrating a circuit configuration of an exhaust particulate matter measurement device according to an embodiment of the present invention.

[Explanation of symbols]

1 case body 5 processing room 6 intake 7 exhaust port 8 Electrical insulation layer 9 Resistance heating type filter element 11 energization control means 13 Resistance measuring means

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3G090 AA01 AA02 BA04 CA01 CB11                       DA07                 3G091 AA18 AB13 BA31 CA03 EA29                 4D019 AA01 BA02 BB09 BD03 CA03                       CB04 CB09

Claims (3)

[Claims] 1. A case body made of heat-resistant metal, a processing chamber having an intake port and an exhaust port which are provided inside the case body and communicate with the outside, and inside the processing chamber, between the intake port and the exhaust port. At the position of, the resistance heating type filter element made of a heat resistant metal is inserted between the inner side surface of the resistance heating type filter element and the inner side surface of the resistance heating type filter, and energization control for energizing the resistance heating type filter element to enable resistance heating. An exhaust particulate matter measuring device comprising: means and a resistance measuring means for measuring electric resistance or electric conductivity between the case body and the resistance heating type filter element. 2. A resistance heating type filter element is obtained by stacking porous metal sheets in multiple layers and interposing a porous electrical insulating film between the facing surfaces of the stacked porous metal sheets.
In addition, the porous metal sheet is formed by corrugating or corrugating the metal sheet material at the same time, and at the same time, forming a large number of through-holes having break-like protrusions on the periphery of the corrugated or corrugated peaks and / or valleys. The exhaust particulate matter measurement device according to claim 1, wherein the exhaust particulate matter measurement device is formed by drilling. 3. A measurement method using the exhaust particle measuring apparatus according to claim 1, wherein the exhaust gas of the processing chamber of the case body is located at a higher flow velocity side of the exhaust gas passage than the intake port. It is placed in the exhaust gas flow path so as to communicate with each other, and the exhaust port side is depressurized more than the intake port side, so that a part of the exhaust gas is taken in from the intake port of the processing chamber to the inside and through the resistance heating type filter element. The resistance of the case body and the resistance heating filter element with a resistance measuring means over time to measure the electric resistance or electric conductivity between the case body and the resistance heating type filter element. Control of energization while indirectly detecting the amount of exhaust particulates deposited so as to bridge the electric insulating layer between the filter element and the resistance heating type filter element To the means The resistance heating type filter element is energized to resistance-heat the resistance heating type filter element to burn the exhaust particulates trapped in the resistance heating type filter element, and thereby the space between the side surface of the processing chamber and the resistance heating type filter element and the inside of the processing chamber. A method for measuring exhaust particulate matter, which comprises regenerating the resistance heating type filter element by burning the exhaust particulate matter that has accumulated in other places as well.