JPH05263630A - Manufacture of catalyst converter and exhaust emission control tool - Google Patents

Abstract

PURPOSE:To provide a product which can be used at a high temperature for a long period with stability, can be comparatively easily installed on an exhaust pipe, bring about a slight thermal loss, and is suitable for an auxiliary catalyst of an internal combustion engine. CONSTITUTION:A catalyst converter 7 is arranged on an exhaust system of an internal combustion engine. An outer peripheral surface of an exhaust gas purification tool is covered with a tubular outer case. The tubular outer case is connected to an exhaust pipe which is not shown in the figure. The exhaust gas purification tool 30 is made of a ceramic pipe 11 whose longitudinal both ends are opened. A catalyst for purifying the exhaust gas is held in an inner peripheral surface 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a catalytic converter and an exhaust gas purifying tool.

[0002]

2. Description of the Related Art Catalytic converters for internal combustion engines that are currently in practical use are mounted at various positions immediately after the engine and between the muffler for various reasons and purposes. For example, in a four-wheeled vehicle having a relatively small engine capacity, there is a catalytic converter immediately after the manifold, on the toe board or under the floor. Also, in vehicles with large engine capacity, there is a catalytic converter under the floor.

Then, a small auxiliary catalyst portion is provided between the manifold and the toe board or the underfloor catalytic converter. That is, a part of hydrocarbons and carbon monoxide in the exhaust gas is oxidized by the auxiliary catalyst close to the manifold, the temperature of the exhaust gas is raised, and the exhaust gas whose temperature has been raised is supplied to the main catalytic converter. As a result, when the engine is still cold, the exhaust gas sent to the main catalytic converter can be preheated and the catalytic converter can be started earlier. Also, if the engine is far away from the main catalytic converter, by preheating the exhaust gas,
It is also possible to compensate for the temperature drop of the exhaust gas before it reaches the main catalytic converter. Particularly, in the exhaust gas regulation test, when the engine is started from a cold state and harmful components in the exhaust gas are measured, it is strongly required to provide an auxiliary catalyst.

Further, in the case of a two-cycle gasoline engine used in a two-wheeled vehicle, the exhaust gas contains a large amount of unburned matter. Therefore, if purified by only the main catalytic converter, a large amount of heat is generated due to the oxidizing action of the catalyst. However, the temperature becomes so high that the catalytic function is lost. Therefore, it is preferable to provide an auxiliary catalyst portion in front of the main catalytic converter to share a part of the unburned portion with the oxidation.

[0005] As such an auxiliary catalyst,
Japanese Patent Publication No. 18 discloses a technique in which a multi-cylinder engine having exhaust pipes of different lengths is lined with a ceramic cloth carrying a catalyst in the exhaust pipe in order to keep the exhaust gas passing through the longer exhaust pipe warm. There is. Actual Kaisho No. 64-51718,
Japanese Utility Model Application Laid-Open No. 63-136217 discloses that the inner peripheral wall of the exhaust manifold or the exhaust pipe downstream thereof is coated with a catalyst material. Further, Japanese Utility Model Application Laid-Open No. 2-87922 describes that the inner peripheral wall of a metal exhaust pipe is coated with ceramics to support the catalyst.

[0006]

In the auxiliary catalyst described in Japanese Utility Model Laid-Open No. 1-136618, since the ceramic cloth is flexible, the cylindrical shape cannot be maintained. Therefore,
Inside the ceramic cloth, a holding material such as a stainless plate having a large number of holes must be installed to hold the ceramic cloth. However, if the holes of the holding material are small, the exhaust gas is difficult to flow through the holes, and the efficiency of the catalyst is low. On the other hand, if the holes of the holding material are large, the catalyst of the ceramic cloth scatters due to the force of the exhaust gas flow. In addition, the material of the ceramic cloth itself, silica cloth does not have heat resistance,
If it is used for a long time, it will be worn out, and alumina cloth or the like is extremely expensive and cannot be used. Moreover, since the ceramic cloth is wound around the holding material and then housed in the exhaust pipe, it takes a lot of time and effort.

In Japanese Utility Model Laid-Open No. 2-87922, a metal exhaust pipe is coated with ceramics. However, when repeatedly exposed to high temperature exhaust gas, the metal exhaust pipe repeats thermal expansion and contraction. Peels off. Further, Japanese Utility Model Application Laid-Open No. 63-136217 discloses that the inner wall of the exhaust pipe is coated with a catalyst, but the method is not specific.

The present inventor has also examined the use of a so-called honeycomb type catalyst, which uses a cylindrical substrate having a large number of communicating holes, as an auxiliary catalyst. However, such a honeycomb type carrier has a large pressure loss, and in order to reduce the pressure loss to the same extent as that of the exhaust pipe, the diameter of the honeycomb type carrier must be twice or more the diameter of the exhaust pipe. But,
In a four-wheeled vehicle, an auxiliary catalyst must be installed in the engine room, but the auxiliary catalyst is large as described above, and moreover, a space for shutting off the heat generation of the auxiliary catalyst is also necessary. The reality is that there is none.
Also in a two-wheeled vehicle, the exhaust pipe is an important design element, and there is no room for providing a honeycomb type carrier having such a large diameter.

An object of the present invention is to provide a product which can be stably used at high temperature for a long time, is relatively easy to mount on an exhaust pipe, has a small pressure loss, and is suitable as an auxiliary catalyst for an internal combustion engine. That is.

[0010]

SUMMARY OF THE INVENTION The present invention is a catalytic converter installed in an exhaust system of an internal combustion engine, comprising a ceramics tube having both ends in the longitudinal direction opened, and a catalyst for purifying exhaust gas. The present invention relates to a catalytic converter including an exhaust gas purifying tool carried on the inner peripheral surface side and a tubular outer shell that covers the outer peripheral surface of the exhaust gas purifying tool and is connected to an exhaust pipe.

Further, according to the present invention, a catalyst for purifying exhaust gas is provided on the inner peripheral surface side of the ceramics tube which is open at both ends in the lengthwise direction and has a large number of projections on the inner peripheral surface. A method of manufacturing a supported exhaust gas purifying tool, comprising forming a ceramic tube molded body, and forming a slurry containing particles forming the protrusions after firing, ceramic raw material powder, water and a binder in the molded body. A method for manufacturing an exhaust gas purifying tool, characterized in that the molded body is adhered to the peripheral surface, then the molded body is dried and fired to obtain a ceramics tube, and then the catalyst is supported on the inner peripheral surface side of the ceramics tube. It is related.

Further, according to the present invention, a catalyst for purifying exhaust gas is provided on the inner peripheral surface side, which is composed of a ceramics tube having both ends in the lengthwise direction opened and a large number of projections provided on the inner peripheral surface. A method of manufacturing a supported exhaust gas purifying tool, comprising forming a molded body of the ceramic tube, and adhering a slurry containing a foaming material, ceramic raw material powder, water, and a binder to the inner peripheral surface, To form a projection on the inner peripheral surface, then fire the molded body to obtain a ceramic tube, and then carry the catalyst on the inner peripheral surface side of the ceramic tube. The present invention relates to a method for manufacturing a purification tool.

[0013]

1 and 2 are perspective views schematically showing exhaust gas purifying tools 20 and 30 according to an embodiment of the present invention, respectively. The exhaust gas purification tool 20 is composed of an elongated cylindrical ceramics tube 1 having open ends. Ceramic tube 1
A catalyst for purifying exhaust gas is carried on the inner peripheral surface 1a of the. The exhaust gas purifying tool 30 is composed of an elongated cylindrical ceramics tube 11 having both ends opened, and the ceramics tube 11 is curved in an arc shape when seen in a plan view. A catalyst for purifying exhaust gas is carried on the inner peripheral surface 11a of the ceramic tube 11.

FIGS. 3 (a), 3 (b) and 3 (c) are sectional views schematically showing an enlarged part of the ceramic tube 1 or 11, respectively. To manufacture the ceramic tube 1 (or 11), proceed as follows. The ceramic tube 1 is manufactured by extrusion molding, and the ceramic tube 11 is cast molding to manufacture a molded body, and the molded body is dried and fired. This compact is molded from a ceramic raw material slurry obtained by mixing ceramic raw material powder, water and a binder. When the ceramic tube 1 (11) is manufactured in this manner, the inner peripheral surface 1a (11a) becomes substantially flat as shown in FIG. 3 (a).

As shown in FIGS. 3 (b) and 3 (c), the inner peripheral surface
A protrusion can be formed on 1a (11a). As this method, for example, a slurry containing particles that form protrusions after firing, ceramic raw material powder, water, and a binder is poured into the inside of the molded body of the ceramic tube 1 (11),
It is attached to the inner peripheral surface of the molded body. Next, this molded body is dried and fired to obtain a ceramic tube 1 (11), and the inner peripheral surface 1a
A catalyst is supported on (11a). Here, as shown in FIG. 3 (b), the slurry forms the ceramic coating 2 after firing, and the particles remain as particles 3 after firing to form protrusions.

In another method, a molded body of the ceramic tube 1 (11) is produced, and a slurry containing a foam material, a ceramic raw material powder, water and a binder is attached to the inner peripheral surface to foam the foam material to form a slurry. Protrusions are formed on the coating, and then the molded body is fired to obtain a ceramics tube 1 (11). Here, as shown in FIG. 3 (c), the above-mentioned slurry forms a ceramic coating 4 after firing, where the foam material is a depression 6 and the periphery of the foam material is a protrusion 5. Become.

It is also possible to use a ceramics tube 21, a part of which is shown in FIG. 3 (d). On the inner peripheral surface 21a of the ceramic tube 21, protrusions having a trapezoidal cross section at regular intervals are formed.
22 are formed. The protrusions 22 are elongated in parallel with each other. In order to manufacture such a ceramic tube 21, a die provided with irregularities having a shape as shown in FIG. 3 (d) is prepared, and a ceramic raw material is extruded using this die. The shape of the cross section of the protrusion 22 in the width direction may be triangular, quadrangular, arc-shaped, or the like.

Next, an example of the catalytic converter will be described. FIG. 4 is a plan view schematically showing the catalytic converter 7, and FIG. 5 is a sectional view taken along the line VV of FIG. In the catalytic converter 7 of this example, the exhaust gas purification tool 30 is shown as canned.

A pair of halves 8 constituting a tubular outer shell is prepared. The body of this half is curved in an arc shape when seen in a plan view, and has a semicircular cross section. Flange 8a on the outer peripheral side of the body
Is provided, and the flange 8b is provided on the inner peripheral side of the main body. Flange 9 for fixing bolts is provided at both ends in the length direction of the main body. The outer periphery of the exhaust gas purification tool 30 is surrounded by the cushioning material 10, and in this state, the exhaust gas purification tool 30 is fixed inside the pair of halves 8 and canned. In FIG. 5, 13 is a seam of a pair of halves 8. The stoppers 12 are fixed to both end surfaces of the exhaust gas purification tool 30. The structure of the converter is not limited to that of this example, and a structure normally used in the honeycomb type carrier can be used. For example, in the case of a motorcycle for which the exterior design is important, the flanges 8a, 8b,
It is preferable to use a cylindrical outer shell in which 9 is omitted. In this case, the outer shell is welded to the exhaust pipe.

According to the above exhaust gas purifying tool, since the exhaust gas flows through the inner space of the ceramic pipe, the pressure loss is extremely small, which is almost the same level as the pressure loss of a normal metal exhaust pipe. Further, since the catalyst is supported on the inner peripheral surface of the ceramics tube, the problems such as the scattering of the catalyst particles from the ceramic cloth and the peeling or cracking of the ceramic coating from the metal exhaust tube as described in the section of the prior art do not occur. Therefore, it can be used stably for a long time.

Further, since the exhaust gas purifying tool is composed of an integrally molded ceramics tube, for example, FIGS.
As shown in FIG. 5, the exhaust gas purifying tool can be housed between the pair of halves. Needless to say, such a tubular exhaust gas purifying tool can also be fixed by being pushed into the inside of the tubular outer shell of one piece. Then, by connecting the tubular outer shell to the exhaust pipe, the exhaust gas purification tool can be installed in the exhaust system.
Therefore, installation of the exhaust gas purification tool is relatively easy.

Further, as shown in FIGS. 3 (b), 3 (c) and 3 (d), if the inner peripheral surface of the ceramic tube is made uneven, the surface area is increased by that much, and the amount of catalyst carried is large. At the same time, a turbulent flow easily occurs in the exhaust gas flow, and the contact between the catalyst and the exhaust gas increases. Therefore, the purification efficiency of the exhaust gas can be increased. 3 (b) and 3 (c), the coefficient of thermal expansion of the ceramic tube 1 (11) and the ceramic coatings 2, 4
The coefficient of thermal expansion is preferably close to each other, and it is more preferable that both are made of the same material. Also, the ceramic coating 2
It is more preferable to use the same material as in (3) and the material of particles 3.

If the material of the ceramic tubes 1, 11, 21 is cordierite, the durability against the temperature change of the exhaust gas becomes the highest, which is practical. This is because cordierite has the smallest thermal expansion amount in ceramics. Further, in this case, it is preferable that the ceramic coatings 2 and 4 and the particles 3 are also made of cordierite. There are two methods for forming the particles 3 with cordierite. In the first method, particles 3 of cordierite that have already been fired are dispersed in the slurry for the coating 2. In the second method, a predetermined amount of talc powder, kaolin powder, and alumina powder, which become cordierite by firing, are mixed with water and a binder, the mixture is granulated, and the granulated particles are coated with a film. Disperse in slurry for 2.

Hereinafter, more specific experimental results will be described. First, the following samples were manufactured. (Sample 1) The ceramic tube 1 made of cordierite shown in FIGS. 1 and 3A was manufactured by the method as described above. The dimensions were 40 mm outer diameter, 3.5 mm wall thickness, and 150 mm total length.

(Sample 2) Water and a binder were added to a powder of talc, kaolin and alumina in a ratio to become cordierite after firing to prepare a slurry. Further, a pair of gypsum molds having a molding space having a shape as shown in FIG. 2 was prepared. The pair of gypsum-shaped pieces has a shape obtained by dividing the ceramic tube 11 into two parts on a plane parallel to the bending direction. Therefore, each gypsum mold is provided with a molding space having a semicircular cross section and an arcuate plane. A pair of such gypsum molds are combined and molded by a so-called sludge casting method, the molded body is dried and fired, both ends of the fired body are cut, and a ceramic tube as shown in FIGS. 2 and 3 (a). Got 11. The dimensions of the ceramic tube 11 were an outer diameter of 40 mm, a wall thickness of 3.5 mm, a central axis length of 150 mm, a central axis angle of 120 °, and a central axis radius of curvature of about 70 mm.

(Sample 3) In the same manner as in “Sample 2”, FIG.
And a ceramic tube 11 as shown in FIG. 3 (b) was manufactured. However, the slurry for forming the coating film 2 was made of the same material as the slurry for the ceramic tube 11. In addition, a mixed slurry consisting of talc powder, kaolin powder, alumina powder, water and binder was extruded from a hole with a diameter of 1 mm and fired to obtain cordierite. The product was passed through and passed through a sieve having a sieve size of 600 μm to disperse the cordierite particles remaining in the sieve into the slurry for the coating film 2. Then, this slurry was poured over the inner peripheral surface of the ceramic molded body so as to evenly spread to a constant thickness, so that the cordierite particles were uniformly dispersed on the inner peripheral surface of the ceramic molded body. As a result, projections having a diameter of about 0.9 mm and a height of about 0.7 mm were formed on the inner peripheral surface 11a of the ceramic tube 11 at an average density of 25 pieces / cm ² .

(Sample 4) The sample shown in FIGS. 2 and 3B was manufactured in exactly the same manner as the sample 3 described above. However,
In the above, when producing the synthetic cordierite particles, the mixed slurry was extruded through a hole having a diameter of 3 mm. Also, after crushing synthetic cordierite, 2.5m
The pulverized material was passed through a m 2 screen, and the passed product was passed through a screen with a screen size of 1.6 mm to disperse the cordierite particles remaining in the screen into a slurry for coating 2. Thus, the density of the protrusions was 6 pieces / cm ² , the diameter was about 2.4 mm, and the height was about 2.2 mm.

(Sample 5) In the same manner as in “Sample 2”, FIG.
And a ceramic tube 11 as shown in FIG. 3 (c) was manufactured. However, the slurry for forming the coating 4 was made of the same material as the slurry for the ceramic tube 11. Also, the film 4
The foaming material was uniformly mixed in the slurry for use at 10% by volume. As the foaming material, particles having a diameter of 0.5 mm in which butane gas was encapsulated in a resin, which foamed at a temperature not higher than the boiling point of water, were used so that the foamed material was foamed in a soft state before being dried. Then, the slurry for the coating film 4 was poured into the inner peripheral surface of the ceramic molded body so as to evenly spread to a uniform thickness, and the foam material was uniformly dispersed on the inner peripheral surface of the ceramic molded body. The ceramic tube 11 thus obtained
On average, 16 crater-shaped projections 5 were formed per square centimeter on the inner peripheral surface 11a. The outer diameter of the protrusion 5 was about 1.2 mm, and the diameter of the recess 6 was about 0.6 mm.

(Sample 6) The ceramic tube 11 shown in FIGS. 2 and 3B was manufactured in the same manner as described in the section of “Sample 3”. However, in this example, first, a tubular molded body is manufactured by a sludge casting method, then the molded body is removed from the gypsum mold, the molded body is dried, and then an opening at one end surface of the molded body is covered with a rubber film. Sealed. Then, the above-mentioned slurry was poured from the opening on the other end surface of the molded body to disperse the cordierite particles on the inner peripheral surface of the molded body. As a result,
The average density of 2 on the inner surface 11a of the ceramic tube 11 after firing.
A protrusion with 3.5 pieces / cm ² , a diameter of about 0.9 mm and a height of about 0.7 mm was formed.

(Sample 7) The ceramic tube 21 shown in FIG. 3 (d) was manufactured by the method described above. However, ceramic tube
The dimensions of 21 were 40 mm in outer diameter, 3.5 mm in wall thickness, and 150 mm in total length. In addition, the inner peripheral surface 21a of the ceramic tube 21 has a bottom width.
Thirty rows of projections 22 having a cross-sectional dimension of 1.5 mm, upper end width 0.6 mm, and height 1 mm were formed, and the projections 22 in each row were equally spaced. (Sample 8) A ceramic tube 21 was manufactured in the same manner as in Sample 7. However, the cross-sectional dimensions of the projections 22 were 3 mm in bottom width, 2 mm in top width, and 2 mm in height, and the projections 22 were formed at equal intervals in 15 rows.

(Comparative Sample 1) γ-alumina was supported on silica cloth and baked. The silica cloth was wound around a stainless pipe having a large number of through holes each having a diameter of about 7 mm and a pitch of 10 mm, and the stainless pipe was inserted into the exhaust pipe and fixed to the exhaust pipe with bolts.

(Comparative sample 2) 50% Al containing 50% thickness
A corrugated stainless steel foil having a pitch of about 2 mm and a height of about 1.5 mm was corrugated to a length of 150 mm and heat-treated at 850 ° C. to deposit aluminum oxide on the surface of the stainless steel foil. Then, γ-alumina was supported and baked. Since this stainless steel foil has no water absorption,
With this method, γ-alumina could be deposited only to a thickness of about 20 μm. This stainless foil was inserted into the gas passage.

(Evaluation of Thermal Durability) The thermal durability of Samples 1 to 8 and Comparative Samples 1 and 2 was evaluated. However, regarding the ceramic tubes of Samples 1 to 8, γ-alumina was coated on the inner peripheral surface to a thickness of about 50 μm and baked,
It was canned as shown in FIG. Then, for each example, a thermal cycle test was performed using combustion gas from a gas burner.

Specifically, hot gas having an inlet gas temperature of 950 ° C. is flown into each sample at a rate of 1 Nm ³ / min for 5 minutes,
Next, air at room temperature was immediately flowed, and this was set as one cycle, and 200 cycles were carried out. During this period, vibration of 200 Hz and 20 G was continuously applied. As a result, in Samples 1 to 8, abnormalities such as cracks did not occur in the ceramic tube, and the γ-alumina coating did not peel off. In comparative sample 1, silica cloth was partly scattered and holes were formed in the holes of the stainless steel pipe. In comparative sample 2, γ-alumina was peeled off and scattered in about 2/3 of the total area of the stainless steel foil.

(Surface Area of Inner Surface and Amount of γ-Alumina Supported) In order to support a large amount of catalyst and improve exhaust gas purification efficiency, it is necessary to increase the surface area of the inner surface of the ceramic tube. Therefore, Table 1 shows the surface areas of the inner peripheral surfaces of the samples 1 to 8 described above. Here, since the inner peripheral surfaces of Samples 1 and 2 are almost flat, they were calculated from the measured dimensions. In addition, regarding Samples 3 to 8, the cross section of the unevenness was magnified 40 times and photographed, the shape of the unevenness was measured, and the surface area was calculated from this measured shape. Further, Table 1 also shows the ratio (%) of the surface area of the inner peripheral surface of each sample when the surface area of the inner peripheral surface of sample 2 was 100 (%).

After the weight of each sample was measured, the sample was immersed in a suspension of γ-alumina, and the amount of γ-alumina adhered (supported amount)
Was measured and is shown in Table 1. In addition, load the amount of sample 2 to 100
Table 1 also shows the ratio of the carried amount of each sample when it is defined as%.

[0037]

[Table 1]

As can be seen from Table 1, in Samples 3 to 8, the surface area of the inner peripheral surface and the amount of γ-alumina supported were Sample 1,
It has increased considerably compared to 2. Further, the surface areas of the inner peripheral surface of Samples 4, 7, and 8 are particularly large, and the amounts of γ-alumina supported are particularly large in Samples 4 and 5.

[0039]

According to the catalytic converter of the present invention, since the exhaust gas flows through the inner space of the ceramic pipe, the pressure loss is extremely small, which is almost the same level as the pressure loss of a normal metal exhaust pipe. Further, since the catalyst is supported on the inner peripheral surface of the ceramics tube, the problems such as the scattering of the catalyst particles from the ceramic cloth and the peeling or cracking of the ceramic coating from the metal exhaust tube as described in the section of the prior art do not occur. Therefore, it can be used stably for a long time.
Further, since the outer peripheral surface of the exhaust gas purifying tool is covered with the tubular outer shell and the outer shell is connected to the exhaust pipe, the exhaust gas purifying tool can be installed relatively easily in the exhaust system of the internal combustion engine.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing an exhaust gas purification tool 20.

FIG. 2 is a perspective view schematically showing an exhaust gas purification tool 30.

3 (a), (b), (c), and (d) are cross-sectional views schematically showing a part of the inner peripheral surface of the ceramic tube of each example.

FIG. 4 is a plan view schematically showing a catalytic converter 7.

5 is a sectional view taken along line VV of FIG.

[Explanation of symbols]

 1,11,21 Ceramics tube 1a, 11a, 21a Inner peripheral surface 2,4 Ceramics coating 7 Catalytic converter 8 A pair of halves constituting outer shell 10 Buffer material 20, 30 Exhaust gas purification tool

Claims (5)

[Claims] 1. A catalytic converter installed in an exhaust system of an internal combustion engine, comprising a ceramics tube having both lengthwise ends open, and carrying a catalyst for purifying exhaust gas on an inner peripheral surface side. A catalytic converter comprising: a gas purification tool; and a tubular outer shell that covers an outer peripheral surface of the exhaust gas purification tool and is connected to an exhaust pipe. 2. The catalytic converter according to claim 1, wherein a large number of protrusions are provided on the inner peripheral surface of the ceramic tube. 3. The catalytic converter according to claim 1, wherein the ceramic tube is made of cordierite. 4. A ceramics tube which is open at both ends in the length direction and has a large number of protrusions on its inner peripheral surface,
A method for manufacturing an exhaust gas purifying tool carrying a catalyst for purifying exhaust gas on the inner peripheral surface side, comprising: forming a molded body of the ceramics tube; A slurry containing water, water and a binder is adhered to the inner peripheral surface of the molded body, the molded body is then dried and fired to obtain a ceramic tube, and the catalyst is supported on the inner peripheral surface side of the ceramic tube. A method for manufacturing an exhaust gas purification tool, comprising: 5. A ceramics tube which is open at both ends in the length direction and has a large number of protrusions on its inner peripheral surface,
A method for manufacturing an exhaust gas purifying tool carrying a catalyst for purifying exhaust gas on the inner peripheral surface side, wherein a molded body of the ceramic tube is produced, and a foam material, a ceramic raw material powder, water and a binder are prepared. The slurry containing is adhered to the inner peripheral surface, the foamed material is foamed to form protrusions on the inner peripheral surface, the molded body is then fired to obtain a ceramics tube, and then the inner peripheral surface side of the ceramics tube. A method for manufacturing an exhaust gas purifying tool, characterized in that the catalyst is supported on a substrate.