JP2007021430A - Manufacturing method of particulate filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a particulate filter enhanced in regeneration treatment capacity by improving the treatment capacity for particulate matter. <P>SOLUTION: The manufacturing method of the particulate filter, which is arranged in the exhaust route of an internal combustion engine and obtained by applying a catalyst layer to a filter carrier, has a process (step S2) for applying a slurry, which is prepared by mixing a catalytic component and organic matter with a liquid medium, to the filter carrier when the catalyst layer is applied to the filter carrier and a process (step S3) for baking the filter carrier coated with the slurry to remove the organic matter and forming recessed parts to the catalyst layer. The treatment capacity of the particulate matter is enhanced by increasing the contact area of the catalyst layer with the particulate matter by the recessed parts formed by removing the organic matter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a particulate filter that collects particulate matter contained in exhaust gas exhausted from an internal combustion engine, particularly a diesel engine.

  An exhaust gas exhausted from an internal combustion engine, particularly a diesel engine, contains particulate matter (PM) mainly composed of soot. Conventionally, an exhaust gas purification device 30 for an internal combustion engine as shown in FIG. 5 has been used to reduce the amount of particulate matter released into the atmosphere. As shown in this figure, an exhaust gas purification device 30 for an internal combustion engine includes a particulate filter 35 disposed in an exhaust passage 34 through which exhaust gas 33 from an exhaust manifold 32 of the internal combustion engine 31 is exhausted, and an upstream of the particulate filter 35. And an oxidation catalyst 36 disposed on the surface. In the exhaust gas purifying apparatus 30, the particulate matter 38 is collected on the surface 37 a of the filter carrier 37 of the particulate filter 35 as shown in FIG. 6. The collected particulate matter 38 is burned by the exhaust gas 33 which has been raised to about 600 ° C. by the engine control and the oxidation catalyst 36. As a result, the collected particulate matter 38 is removed, and the regeneration process of the particulate filter 35 is performed.

  In Patent Document 1, when a catalyst layer is attached to an exhaust gas purification filter carrier of an internal combustion engine, a slurry in which a catalyst component is mixed in a fluid medium that can pass through a porous wall portion is applied to the filter carrier. The catalyst component attached to the wall portion while sequentially flowing from at least one of the inlet side and the outlet side of the plurality of parallel through spaces partitioned by the wall portion and allowing the fluid medium to flow out through the wall portion Is deposited on at least one side of the wall so that the catalyst layer for purifying gaseous pollutant components can be uniformly and easily managed with respect to the exhaust gas purification filter carrier of the internal combustion engine. A method for manufacturing an exhaust gas purifying filter carrier for an internal combustion engine is described.

JP 2002-663338 A

  However, although the exhaust gas purification apparatus 30 for an internal combustion engine described above can remove the exhaust gas 33 by heating it up and burning the particulate matter 38, the fuel consumption deteriorates due to an increase in exhaust loss due to the unburned particulate matter 38. There is a possibility of letting you.

  In the exhaust gas purification filter carrier of the internal combustion engine described in Patent Document 1, the catalyst layer is an oxidation catalyst for purifying unburned components such as HC and CO, and the particulates deposited on the particulate filter by the action of the oxidation catalyst. Although the particulate matter is oxidized and the particulate filter is regenerated, the particulate matter remaining without being oxidized may increase the exhaust loss and deteriorate the fuel consumption. Furthermore, there is a possibility that the performance of the regeneration process of the particulate filter is deteriorated due to the deterioration of the oxidation catalyst.

  Therefore, the present invention has been proposed in view of the above-described problems, and an object of the present invention is to provide a method for manufacturing a particulate filter in which the performance of regeneration processing is improved by improving the processing capacity of the particulate matter. .

  A method for manufacturing a particulate filter according to a first invention that solves the above-described problem is a method for manufacturing a particulate filter that is disposed in an exhaust path of an internal combustion engine and that has a catalyst layer attached to a filter carrier. When attaching a catalyst layer to a carrier, a step of applying a slurry in which a catalyst component and an organic substance are mixed in a fluid medium, and firing the filter carrier on which the slurry is applied to remove the organic substance, thereby removing the catalyst. And a step of forming a recess in the layer.

  The method for producing a particulate filter according to the second invention for solving the above-described problem is a method for producing a particulate filter according to the first invention, wherein the organic substance is polyethylene glycol. To do.

  The method for producing a particulate filter according to the third invention for solving the above-described problem is the method for producing a particulate filter described in the first or second invention, wherein the organic substance is a solid weight of the slurry. It is characterized by being 5 wt% to 50 wt%.

  A method for manufacturing a particulate filter according to a fourth invention for solving the above-described problem is a method for manufacturing a particulate filter according to any one of the first to third inventions, wherein the particle size of the organic substance is set. The average particle diameter of the particulate matter adhering to the catalyst layer is larger.

  A method for manufacturing a particulate filter according to a fifth invention for solving the above-described problem is the method for manufacturing a particulate filter according to any one of the first to fourth inventions, wherein the particle size of the organic substance is set. 1 μm to 50 μm.

  According to the method for producing a particulate filter according to the first aspect of the present invention, the surface area of the catalyst layer is increased, that is, the contact area between the particulate matter and the catalyst layer is increased by the recess formed when the organic matter is removed. Improve the processing capacity of particulate matter. As a result, the unit area of the particulate filter and the removal rate of particulate matter per unit time increase, so the remaining particulate matter decreases and exhaust pressure loss can be reduced, and the output of the internal combustion engine is increased. Moreover, it is possible to contribute to improvement of reliability and improvement of fuel consumption by low temperature regeneration combustion.

  According to the method for manufacturing a particulate filter according to the second invention, the same effect as the method for manufacturing the particulate filter described in the first invention can be obtained, and the same particle size can be used, or a predetermined particle size can be obtained. It becomes easy to control the particle size such as distribution, and the surface roughness of the catalyst layer can be adjusted appropriately.

  According to the method for manufacturing a particulate filter according to the third invention, the same effect as the method for manufacturing the particulate filter described in the first and second inventions can be obtained, and the surface roughness of the catalyst layer can be further increased. It can be adjusted appropriately.

  According to the method for manufacturing a particulate filter according to the fourth invention, the same effect as the method for manufacturing the particulate filter described in the first to third inventions can be obtained. Since it is larger than the average particle size of the matter, the ratio of the recesses formed in the catalyst layer can be adjusted appropriately, the particulate matter can be collected efficiently, and the collected particulate matter and catalyst Since the layer can be efficiently contacted, more particulate matter can be processed as compared with the conventional particulate filter.

  According to the method for manufacturing a particulate filter according to the fifth invention, the same effect as the method for manufacturing the particulate filter described in the first to fourth inventions can be obtained, and the particle size of the organic substance is made more specific. By doing so, more particulate matter can be processed more reliably.

  Hereinafter, the best mode for carrying out the method for producing a particulate filter according to the present invention will be specifically described based on examples.

Hereinafter, a method for manufacturing a particulate filter according to the first embodiment will be described with reference to the drawings.
FIG. 1 is a schematic view of an exhaust gas treatment apparatus for an internal combustion engine having a particulate filter manufactured by a particulate manufacturing method according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the encircling line (II) in FIG. FIG. 3 is a diagram showing a flow of a method for manufacturing a particulate filter according to the first embodiment of the present invention.

  A particulate filter 20 manufactured by the method for manufacturing a particulate filter according to the first embodiment of the present invention is connected to an exhaust manifold 2 from which an exhaust gas 24 is exhausted from an internal combustion engine 1 as shown in FIG. The exhaust passage (exhaust passage) 3 is disposed. The intake side of the internal combustion engine 1 includes an intake valve 5 that opens and closes the intake port 4, an intake branch pipe 6 that communicates with the intake port 4, and an air cleaner 8 that is disposed upstream of the intake branch pipe 6. An exhaust valve 10 for opening and closing the exhaust port 9 is provided on the exhaust side of the internal combustion engine 1, and the exhaust port 9 communicates with the exhaust manifold 2. The exhaust manifold 2 and the surge tank 11 provided in the intake branch pipe 6 are connected to each other via an exhaust gas recirculation passage 12, and an electric control type EGR control valve (not shown) is provided in the exhaust gas recirculation passage 12. Be placed. The internal combustion engine 1 includes a cylinder head 13, a cylinder block 14 disposed below the cylinder head 13, a piston 15 disposed in the cylinder block 14, and a combustion chamber 16 defined by the piston 15 and the cylinder head 13. Have

The particulate filter 20 described above has a catalyst layer attached to the filter carrier, and is manufactured by the following procedure when the catalyst layer is attached to the filter carrier.
As shown in FIG. 3, first, a slurry is prepared by mixing a catalyst component that promotes oxidation of particulate matter and an organic substance in silica sol and water that are fluid media (step S1). However, the organic substance is 5 wt% to 50 wt% with respect to the solid weight of the slurry.
In addition, solid weight is the weight of the solid substance contained in a slurry.

  Examples of the catalyst component include alkali metals, alkaline earth metals, noble metals such as Pt, Pd, and Rh, Ni, Co, and Ce.

  Examples of the organic substance include carbon that can be burned and removed at about 500 ° C. to about 600 ° C., polyethylene glycol, and the like. In addition, polyethylene glycol that allows easy control of the particle size such as the same particle size or a predetermined particle size distribution is preferred. However, the particle size of the organic substance is in the range of 1 μm to 50 μm, and preferably in the range of 20 μm to 30 μm. By setting the particle size of the organic material to 50 μm or less, the strength of the catalyst layer of the particulate filter can be maintained.

Subsequently, the slurry is applied to the filter carrier (step S2).
Further, the filter carrier on which the slurry is applied is baked at the combustion temperature of the organic matter, and the organic matter is burned and removed. At this time, the recess 40 is formed in the catalyst layer 22 (step S3). Therefore, as described above, by setting the particle size of the organic material to be equal to or greater than the average particle size of the particulate matter, the particulate matter is efficiently collected in the catalyst layer of the particulate filter.

  As shown in FIG. 2, the particulate filter 20 manufactured by such a procedure has a filter carrier 21 and a catalyst layer 22 applied to the surface of the filter carrier. However, since the portion from which the organic substance has been removed becomes the recess 40 as described above, the unevenness of the catalyst layer 22 is more complicated than the conventional particulate filter in which the catalyst layer is simply applied to the surface of the filter carrier. Is formed. Therefore, the contact area between the catalyst layer 22 of the particulate filter 20 and the particulate matter 23 in the exhaust gas increases.

[Comparative example]
First, a catalyst component that promotes oxidation of particulate matter and reduces its combustion temperature is mixed into a fluid medium to produce a slurry. Examples of the catalyst component include alkali metals, alkaline earth metals, noble metals such as Pt, Pd, and Rh, Ni, Co, and Ce.
Subsequently, the slurry is applied to a filter carrier and dried to prepare a particulate filter (comparison).

[Evaluation]
Here, in the particulate filter (No. 1) manufactured by the above-described method for manufacturing a particulate filter according to the first embodiment of the present invention and the above-described particulate filter (comparison), the particulate filter is raised. The relationship of the CO ₂ generation amount when the temperature is raised will be described with reference to FIG. Here, the CO ₂ generation start temperature is set as the combustion start temperature of the particulate matter.
FIG. 4 is a diagram showing the combustion start temperature of the particulate filter produced by the particulate filter production method according to the first embodiment of the present invention and the particulate matter collected by the conventional particulate filter. is there. In FIG. 4, a solid line indicates the case of the particulate filter (No. 1) manufactured by the method for manufacturing a particulate filter according to the first embodiment of the present invention, and a broken line indicates a conventional particulate filter (No. 1). The conventional case is shown.

As shown in this figure, it was found that the particulate filter (No. 1) was lower than the particulate filter (comparison) at the combustion start temperature of the particulate matter. That is, the particulate filter (No. 1) is obtained by increasing the surface area of the catalyst layer as compared with the particulate filter (conventional), and further increasing the irregularities of the catalyst layer to be larger than the particulate matter. It turned out that the processing capacity of the collected particulate matter has improved.
Further, there is a case where it is not necessary to arrange an oxidation catalyst for raising the temperature of the exhaust gas in front of the particulate filter due to the improvement of the processing capacity.

  Therefore, according to the particulate filter manufactured by the particulate filter manufacturing method according to the first embodiment of the present invention, the surface area of the catalyst layer is increased by the recess formed when the organic matter is removed, that is, The contact area between the particulate matter and the catalyst layer is increased to improve the processing capacity of the particulate matter. As a result, the unit area of the particulate filter and the removal rate of particulate matter per unit time increase, so the remaining particulate matter decreases and the exhaust pressure loss can be reduced, increasing the output of the internal combustion engine. Moreover, it is possible to contribute to improvement of reliability and improvement of fuel consumption by low temperature regeneration combustion.

  In addition, by using polyethylene glycol as the organic substance, it is easy to control the particle size, for example, by aligning to the same particle size or setting a predetermined particle size distribution, and the surface roughness of the catalyst layer can be adjusted appropriately. it can. Furthermore, the surface roughness of a catalyst layer can be adjusted more appropriately by making the said organic substance into 5 wt%-50 wt% with respect to the solid weight of a slurry. In addition, by setting the particle size of the organic substance to 1 μm to 50 μm, which is larger than the average particle size of the particulate matter, the concave portion ratio formed in the catalyst layer can be appropriately adjusted, and the particulate matter can be efficiently Since the collected particulate matter can be efficiently brought into contact with the catalyst layer, more particulate matter can be treated as compared with the conventional particulate filter.

  The present invention can be used in a method for manufacturing a particulate filter that collects particulate matter contained in exhaust gas exhausted from an internal combustion engine, particularly a diesel engine.

1 is a schematic view of an exhaust gas treatment apparatus for an internal combustion engine having a particulate filter manufactured by a particulate manufacturing method according to a first embodiment of the present invention. It is an expanded sectional view of the surrounding line II in FIG. It is a figure which shows the flow of the manufacturing method of the particulate filter which concerns on 1st Example of this invention. It is a figure which shows the combustion start temperature of the particulate filter manufactured with the particulate filter manufactured with the manufacturing method of the particulate filter which concerns on 1st Example of this invention, and the conventional particulate filter. It is the schematic of the exhaust gas processing apparatus of the internal combustion engine which has the particulate filter manufactured by the manufacturing method of the conventional particulate filter. FIG. 6 is an enlarged sectional view of a surrounding line (VI) in FIG. 5.

Explanation of symbols

1 Internal combustion engine 2 Exhaust manifold 3 Exhaust passage 4 Intake port 5 Intake valve 6 Intake branch pipe 8 Air cleaner 9 Exhaust port 10 Exhaust valve 11 Surge tank 12 Exhaust gas recirculation passage 13 Cylinder head 14 Cylinder block 15 Piston 16 Combustion chamber 20 Particulate Filter 21 Filter carrier 22 Catalyst layer 23 Particulate matter 24 Exhaust gas 30 Exhaust gas purification device 31 for internal combustion engine Internal combustion engine 32 Exhaust manifold 33 Exhaust gas 34 Exhaust passage 35 Particulate filter 36 Oxidation catalyst 37 Filter carrier 38 Particulate matter 40 Recess

Claims (5)

A method for manufacturing a particulate filter, which is disposed in an exhaust path of an internal combustion engine and has a catalyst layer attached to a filter carrier,
When attaching a catalyst layer to the filter carrier,
Applying a slurry in which a catalyst component and an organic substance are mixed in a fluid medium;
And a step of forming a recess in the catalyst layer by baking the filter carrier coated with the slurry to remove the organic matter. A method for manufacturing a particulate filter according to claim 1,
The method for producing a particulate filter, wherein the organic substance is polyethylene glycol. A method for manufacturing a particulate filter according to claim 1 or claim 2,
The organic material is 5 wt% to 50 wt% with respect to the solid weight of the slurry. A method for manufacturing a particulate filter according to any one of claims 1 to 3,
The method for producing a particulate filter, wherein the particle size of the organic substance is larger than the particle size of the particulate matter adhering to the catalyst layer. A method for manufacturing a particulate filter according to any one of claims 1 to 4,
The method for producing a particulate filter, wherein the organic substance has a particle size of 1 μm to 50 μm.

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