JPH0828255A - Converter for exhaust emission control - Google Patents

Abstract

PURPOSE:To provide a converter for exhaust emission control which is structured in a compact manner to improve emission control performance and have sufficient heat resistance. CONSTITUTION:A converter for exhaust emission control comprises a metallic case 1; a catalyst carrier 4 made of ceramic contained in the metallic case; and a cushioning material 2 arranged therebetween. The cushioning material 2 is formed of a metallic corrugated sheet formed in such a manner to bend a heat resistant alloy sheet in a wave-form state and has a surface on which a catalyst component is carried. The cushioning materials 2 are disposed in such a state that exhaust gas flows therethrough and interjoined between the metallic case 1 and the catalyst carrier 4 in such a manner that the cushioning material is expanded and contracted in the directions of the crest part and the root part of the metallic corrugated sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying converter mounted on an internal combustion engine of an automobile or the like, and more particularly to a cushioning material therefor.

[0002]

2. Description of the Related Art An exhaust gas purifying converter is a device for removing harmful components in exhaust gas of an internal combustion engine. A conventional converter for purifying exhaust gas is disclosed, for example, in Japanese Examined Patent Publication No. 51-4853.
As shown in No. 0, there is one using a ceramic catalyst carrier.

This conventional exhaust gas purifying converter 90
As shown in FIGS. 7 and 8, the metal woven fabric 3 is disposed between the metal case 1 and the catalyst carrier 40 as a cushioning material for protecting the catalyst carrier 40 which is weak against vibration and impact. In addition, a flexible seal material 5 and a supporter 6 for preventing the seal material 5 from scattering are provided on both ends of the metal fabric 3.
Is arranged. Further, as shown in FIG. 8, the catalyst carrier 40 is a ceramic honeycomb structure having a plurality of exhaust gas passages 410, and the surface thereof carries catalyst components.

Next, when the exhaust gas purifying converter purifies the exhaust gas, the exhaust gas generated from the internal combustion engine flows in through the inlet 11 in the direction of the arrow shown in FIG. The gas is purified by the action of the catalyst while passing through the exhaust gas passage 410 and is discharged from the outlet 12. At this time, the exhaust gas does not pass through the metal fabric 3 due to the presence of the sealing material 5. That is, all the exhaust gas generated from the internal combustion engine passes through the catalyst carrier 4 to be purified and then discharged. In addition, the use environment of the exhaust gas purifying converter 90 at this time becomes a high temperature of approximately 800 ° C.

[0005]

However, the conventional exhaust gas purifying converter 90 has the following problems. That is, in the exhaust gas purifying converter 90, a space for accommodating the catalyst carrier 40 for purifying the exhaust gas is required in the metal case 1, and a space for accommodating the metal fabric 3 which is not involved in the exhaust gas purifying action at all. is necessary. Therefore, the exhaust gas purifying converter cannot be made compact. Further, if an attempt is made to increase the purification capacity of the exhaust gas purifying converter, the metal case also becomes large in size, and it is not possible to satisfy both compactness and improvement of the purification capacity at the same time.

The present invention has been made in view of such conventional problems, and provides an exhaust gas purifying converter having a compact structure, capable of improving the purifying ability, and having sufficient heat resistance. Is what you are trying to do.

[0007]

According to the present invention, there is provided an exhaust gas purifying converter comprising a metal case, a ceramic catalyst carrier housed in the metal case, and a buffer material disposed between the metal case and the buffer material. It consists of a corrugated metal plate made of a heat-resistant alloy plate bent in a corrugated form, and carries a catalyst component on the surface thereof, and the buffer material is arranged so that exhaust gas can flow therethrough, and the metal case and An exhaust gas purifying converter is characterized in that it is joined to a catalyst carrier so as to be expandable and contractable in the direction of the peaks and valleys of the metal corrugated plate.

What is most noticeable in the present invention is that the above-mentioned cushioning material is made of the above-mentioned metal corrugated sheet and carries a catalyst component on the surface thereof. Further, the cushioning material is arranged so that exhaust gas can flow, and is joined between the metal case and the catalyst carrier so as to be capable of expanding and contracting in the direction of the peaks and valleys of the metal corrugated plate. There is something to do.

The cushioning material is arranged between the metal case and the catalyst carrier, and the peaks and valleys are located along the flow direction of the exhaust gas. That is, it has a structure in which a part of the exhaust gas flows between the metal corrugated plate and the metal cases on both sides thereof, and the peaks and valleys between the catalyst carrier. Further, the metal corrugated plate is arranged so as to be expandable and contractable in the direction of the crests and troughs, that is, in the thickness direction of the metal corrugated plate, and the crests are joined to the metal case and the troughs to the catalyst carrier. This joining is performed on all or part of the peaks and valleys. In addition, one peak or valley is joined along its entire length or partial length.

The cushioning material has at least one joining point on the contact line between the inner circumferential surface of the cushioning material and the outer circumferential surface of the catalyst carrier, and the outer circumferential surface of the cushioning material and the inner circumference of the metal case. It is preferable to have at least one junction on the contact line with the surface. This allows the bumps to be easily joined to the metal case at their peaks, and
The valley can be easily joined to the catalyst carrier. The joining is performed by a method such as YAG laser irradiation or Ni brazing.

The buffer material is Fe (iron) -Cr.
A heat-resistant material such as (chrome) -Al (aluminum) alloy or Ni (nickel) -Cr-Al is used. Among them, especially Fe-Cr-Al alloy can obtain heat resistance equivalent to that of the catalyst carrier made of ceramic, and can sufficiently withstand use under high temperature.

An example of the catalyst carrier is a monolithic carrier having a honeycomb structure. In addition, as the catalyst component supported on the catalyst carrier and the buffer material, Pt, P
d, Rh, etc.

[0013]

In the exhaust gas purifying converter of the present invention, when the exhaust gas generated from the internal combustion engine flows into the metal case, it passes through not only the catalyst carrier but also the buffer material. At this time, since the catalyst component is carried on the surface of the cushioning material, the exhaust gas passing through the cushioning material is purified and discharged as in the case of passing through the catalyst carrier.

That is, the effective cross-sectional area for purifying the exhaust gas is almost the entire surface of the metal case. Therefore, in order to obtain an exhaust gas purification effect equivalent to that of the conventional exhaust gas purification converter, a metal case having a cross-sectional area equivalent to that of the conventional catalyst carrier can be used, and the exhaust gas purification converter as a whole can be made compact. Can be planned.

Further, in the case of an exhaust gas purifying converter of the same size as before, purification by a cushioning material is added in addition to purification by the catalyst carrier, and excellent purifying ability is exhibited.

The exhaust gas purifying converter has a high temperature of about 800 ° C. during its use. At this time, the gap between the catalyst carrier and the metal case changes due to the influence of the difference in the coefficient of thermal expansion of each part. However, since the cushioning material is stretchably joined between the catalyst carrier and the metal case, the cushioning material can be stretched while maintaining each joined state. Further, since the above-mentioned cushioning material has sufficient heat resistance, it has elasticity equal to that at room temperature even at high temperature. That is, the above-mentioned cushioning material can sufficiently exert its function as a cushioning material that protects the catalyst carrier even in a high temperature state.

Therefore, according to the present invention, it is possible to provide an exhaust gas purifying converter having a compact structure, capable of improving the purifying ability, and having sufficient heat resistance.

[0018]

EXAMPLE An exhaust gas purifying converter according to an example of the present invention will be described with reference to FIGS. As shown in FIG. 1, the exhaust gas purifying converter 10 of this example includes a metal case 1, a ceramic catalyst carrier 4 housed in the metal case 1, and a cushioning material 2 disposed between the metal case 1 and the metal case 1.

The cushioning material 2 is made of Fe with a thickness of 0.05 mm.
As shown in FIGS. 2 to 6, a -20% Cr-5% Al alloy plate is used to form a corrugated metal corrugated plate. The pitch between the peaks 21 and 22 of the cushioning material 2 is 1.25 mm,
The length is 95 mm. Further, the surface of the cushioning material 2 carries a catalyst component. Further, as shown in FIG. 6, the cushioning material 2 is arranged so that exhaust gas can flow therethrough. As shown in FIGS. 4 and 5, the metal case 1 and the catalyst carrier 4 are joined so as to be capable of expanding and contracting in the direction of the peaks 21 and the valleys 22 of the metal corrugated plate.

These will be described in detail below. That is, as shown in FIG. 3, the cushioning material 2 has a valley portion 22 on its inner peripheral surface that is in contact with the outer peripheral surface of the catalyst carrier 4.
Then, on each contact line of each valley portion 22, there is one joint point 220 at which the catalyst carrier 4 and the valley portion 22 are joined at the center of the line segment. Further, the cushioning material 2 has a mountain portion 21 on its outer peripheral surface that contacts the inner peripheral surface of the metal case 1. Further, also on each contact line of each mountain portion 21, there is a single junction point 210 (FIG. 1) that joins the metal case 1 and the mountain portion 21 in the center of the line segment.

At room temperature, the cushioning material 2 is arranged between the metal case 1 and the catalyst carrier 4 in such a shape that the peaks and valleys are crushed as shown in FIG. Further, the buffer material 2, the catalyst carrier 4 and the metal case 1 are joined by YAG laser irradiation.

As the catalyst carrier, as shown in FIG. 6, a ceramic monolith having a plurality of honeycomb-shaped exhaust gas passages 41 is used. The outer diameter is a column having a diameter of 80 mm and a length of 95 mm. The plurality of exhaust gas passages 41 are provided with a cell wall thickness of 0.17 mm and a cell pitch of 1.27 mm. Further, as the catalyst component supported on the catalyst carrier 4 and the buffer material 2, R
t, Pd and Rh are used.

The metal case 1 is made of SUS430.
The cylinder is used. The cylinder has dimensions of 82 mm inside diameter, 85 mm outside diameter, and 95 mm length. Therefore, at room temperature, the distance D1 (FIG. 4) between the metal case 1 and the cushioning material 4 is about 1 mm. An inflow port 11 and an outflow port 12 are provided in front of and behind the metal case 1, as shown in FIG.

Next, the function and effect of this example will be described. In the exhaust gas purifying converter 10 of this example, when the exhaust gas generated from the internal combustion engine flows into the metal case 1 through the inflow port 11, the exhaust gas passes through not only the catalyst carrier 4 but also the buffer material 2. At this time, since the catalyst component is carried on the surface of the buffer material 2, the exhaust gas passing through the buffer material 2 is purified and discharged in the same manner as when passing through the catalyst carrier 4.

That is, the cross-sectional area effective for purifying the exhaust gas is almost the entire surface of the metal case 1. Therefore, in order to obtain an exhaust gas purification effect equivalent to that of a conventional exhaust gas purification converter,
It is possible to use a small-diameter metal case 1 having a cross-sectional area equivalent to that of a conventional catalyst carrier, and it is possible to make the exhaust gas purifying converter 10 compact as a whole.

Further, in the case of an exhaust gas purifying converter of the same size as before, purification by the cushioning material 2 is added in addition to purification by the catalyst carrier 4, and excellent purifying ability is exhibited.

Further, the exhaust gas purifying converter 10 has a high temperature of about 800 ° C. during its use. At this time, the gap D2 between the catalyst carrier 4 and the metal case 1 is widened due to the influence of the difference in the coefficient of thermal expansion between the respective parts, as shown in FIG.

However, since the cushioning material 2 is stretchably joined between the catalyst carrier 4 and the metal case 1, as shown in FIG. 5, it is possible to stretch the cushioning material while maintaining each joined state. Further, since the buffer material 2 has sufficient heat resistance, it has elasticity equivalent to that at room temperature even at high temperature. That is, the cushioning material 2 can sufficiently exert its function as a cushioning material that protects the catalyst carrier 4 even in a high temperature state.

Next, the exhaust gas purifying converter 10 of the present example.
Was left for 100 hours in an electric furnace maintained at 800 ° C., which is the operating environment condition, and a durability test was performed. As a result, the surface of the metal case 1 and the surface of the cushioning material 2 were only slightly oxidized, and other parts were not changed at all. Therefore, it can be said that the cushioning material 2 relaxes the influence of the difference in thermal expansion due to high temperature by stretching and sufficiently fulfills the function as the cushioning material. In addition, a vibration test similar to that when the automobile was running was also performed during the above durability test. As a result, it did not cause any trouble and had a sufficient function as a cushioning material.

Therefore, according to this example, it is possible to obtain an exhaust gas purifying converter which has sufficient heat resistance, is compact, and has excellent purifying ability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an exhaust gas purifying converter according to an embodiment.

FIG. 2 is a cross-sectional perspective view taken along the line AA of FIG.

FIG. 3 is an explanatory diagram of a joint point between a buffer material and a catalyst carrier in the exhaust gas purifying converter according to the embodiment.

FIG. 4 is an explanatory view of the action of the cushioning material in the exhaust gas purifying converter according to the embodiment (at room temperature).

FIG. 5 is an explanatory view of the action of the cushioning material in the exhaust gas purifying converter according to the embodiment (at high temperature).

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a vertical cross-sectional view of an exhaust gas purifying converter according to a conventional example.

8 is a sectional view taken along the line BB of FIG.

[Explanation of symbols]

 1. ． ． Metal case, 2. ． ． Cushioning material, 21. ． ． Yamabe, 22. ． ． Tanibe, 210, 220. ． ． Junction point, 4. ． ． Catalyst carrier, 41. ． ． Exhaust gas passage,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nishimura 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihondenso Co., Ltd.

Claims (3)

[Claims] 1. An exhaust gas purifying converter comprising a metal case, a ceramic catalyst carrier housed in the metal case, and a cushioning material disposed between the two, wherein the cushioning material is a corrugated heat-resistant alloy plate. It is composed of a metal corrugated sheet that is bent at the same time and has a catalyst component supported on its surface, and the cushioning material is arranged so that exhaust gas can flow, and
An exhaust gas purifying converter, wherein the metal case and the catalyst carrier are joined so as to be capable of expanding and contracting in the direction of the peaks and valleys of the corrugated metal plate. 2. The cushioning material according to claim 1, wherein the cushioning material has at least one joining point on a contact line between the inner circumferential surface of the cushioning material and the outer circumferential surface of the catalyst carrier, and the outer circumferential surface of the cushioning material. An exhaust gas purifying converter having at least one junction on the contact line with the inner peripheral surface of the metal case. 3. The exhaust gas purifying converter according to claim 1, wherein the buffer material is a Fe—Cr—Al alloy.