JP3361169B2 - How to install a converter heat-insulating sealing material for automotive exhaust gas purification - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter for purifying exhaust gas and a method for manufacturing the same, and more particularly, to assembling a seal member between a shell around a catalyst holder and a shell. 2. Description of the Related Art Conventionally, as shown in FIG. 4, an exhaust gas purifying converter 9 mounted on a vehicle is mainly
A catalyst holding body 94, a metal shell 92 covering the outside of the catalyst holding body 94, and a buffer sealing material 93 disposed between the two.
And The catalyst holder 94 carries a catalyst such as platinum. As the catalyst holder 94, for example, a cordierite carrier whose cross section is formed into a honeycomb shape is used. In FIG. 4, reference numeral 910 denotes an exhaust pipe 95.
This is a mounting flange. [0005] Next, as shown in FIG. 5, an inorganic sheet 932 whose outer peripheral portion is reinforced by a metal net 931 is used as the cushioning sealing material 93. The inorganic sheet 932 is formed by molding a mixture of vermiculite and ceramic fibers into a sheet. The cushioning sealing material 93 prevents the catalyst holder 94 from being damaged when the catalyst holding member 94 comes into contact with the outer peripheral metal shell while the vehicle is running or the like.
This is used to prevent the exhaust gas from leaking from between the catalyst holder 94 and the catalyst holder 94. In recent years, metal nets 9
A converter using only the inorganic sheet 932 without using the 31 is also used. [0004] However, the vermiculite used for the cushioning sealing material 93 is as follows.
At a high temperature of the exhaust gas, the moisture contained therein gradually evaporates. Therefore, the expansion pressure of the cushioning sealing material decreases during long-term use. Therefore, a gap is formed between the shell 92 and the catalyst holder 94,
The buffering property and the sealing property are reduced. In particular, when the temperature of the vermiculite exceeds 850 ° C., the above-mentioned water evaporation is remarkable. Further, in a lean burn engine which has been widely used in recent years for improving fuel efficiency, an exhaust gas temperature may exceed 950 ° C. For this reason, a further reduction in the expansion pressure of vermiculite becomes a problem. [0005] Therefore, it is conceivable to use a cushioning sealing material made of a ceramic fiber layer which is excellent in heat resistance and does not lower the expansion pressure. In this case, as shown in FIG. 6, the periphery of the catalyst holder 94 is covered with a ceramic fiber layer 96 like a futon, and these are buried between the lower shell 921 and the upper shell 922. is there. However, ceramic fibers are very brittle materials. For this reason, as shown in FIG.
When the ceramic fiber layer 96 is incorporated between the first and lower shells 922 and the catalyst holder 94, if a strong force is applied or rubbed, the powder is easily powdered. In particular, as described above, when the surroundings of the catalyst holder 94 are covered with the ceramic fiber layer 96 and forced to be inserted between the lower shell 922 and the upper shell 921, the corners 920 of both shells and the ceramic fiber layer A significant friction or pressing force acts on the contact portion 961 of the
In this case, the ceramic fiber layer collapses, and does not serve as a cushioning sealing material. Therefore, a conventional sealing material using vermiculite (trade name: Intramat (manufactured by 3M),
In the case of Ibi Wool Flex (made by IBIDEN))
Add a binder such as emulsion latex to ceramic fiber and vermiculite, wet-mold and mold, then take a complicated process such as pressing and drying,
Although the thickness at the time of setting is reduced so that it can be easily attached to the exhaust gas converter, not only the problem of the heat resistance but also a disadvantage that the production cost is high because a complicated process is taken. SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a converter heat-insulating seal material for purifying an exhaust gas, which can be assembled at a low cost without deterioration of the seal layer at a high temperature and without damaging the seal layer. It seeks to provide a way. SUMMARY OF THE INVENTION The present invention is directed to an automobile exhaust gas purifying system comprising a catalyst support, a shell covering the outside of the catalyst support, and a ceramic fiber layer disposed between the two. and have your installation, <br/> adiabatic sealant converter, the alumina fibers in the portion of the catalyst holder side nonwoven
And a non-woven silica-alumina fiber on the shell side
After the nonwoven fabric of the plate-like or cylindrical Jose La Mick fibers double structure formed by arranging cloth was placed on the inner side of the shell, its
Luke put shell and said fiber nonwoven fabric in the air-tight sheet, and heat sealed pinched by thermal fusion film
After, by reducing the internal pressure, the bulk density of the ceramic fiber layer with a 0.10 to 0.40 g / cm ^3, assembling the thickness of the ceramic fiber nonwoven fabric of the shell and the catalyst carrier after the was reduced to 1.0 to 2.5 times the thickness of the clearance dense closed,
Then, the non-woven ceramic fiber sealed under reduced pressure
The catalyst holder is applied to the inside of a cloth , and
An attachment method of the heat insulating sealant to vehicle exhaust gas purification converter, which comprises assembling by pressurizing the upper and lower shell located. First, for example, a honeycomb-shaped catalyst holder is used as the catalyst holder. The catalyst support is made of, for example, cordierite, alumina or chromium-based stainless steel. The shell is, for example, an elliptical or circular tube having a cross section. The shell is made of, for example, metal. Further, the airtight sheet covers the ceramic fiber layer at the same time as the shell, and is used for easily burying the ceramic fiber layer between the shell and the catalyst holder as described later. is there. Further, the converter having the above structure is connected to an exhaust gas pipe in an automobile manufacturing plant. And
During the test operation, the airtight sheet is incinerated by high-temperature exhaust gas. Alternatively, the airtight sheet may be incinerated before connecting the converter to the exhaust gas pipe. [0010] Next, the above-mentioned method of attaching the converter heat-insulating sealing material for purifying automobile exhaust gas is as follows. After a plate-shaped or cylindrical-shaped ceramic fiber is placed inside a shell, the ceramic fiber is put into a bag made of an airtight sheet. Depressurize,
The opening of the airtight sheet is stuck with hot melt or an adhesive, etc., and completely sealed. Alternatively, a heat-sealing film is used as the airtight sheet, sandwiched from above and below, and then the inside of the heat-sealing film is bonded by hot melt while depressurizing the inside, and completely sealed to form a fiber seal. This reduces the thickness of the fiber seal. The thickness of the ceramic fiber in the fiber seal must be 1.0 to 2.5 times the clearance between the catalyst support and the shell. If the thickness is less than one time the clearance, that is, thin, the position of the catalyst holder is shifted during handling and transportation after assembling the converter, and in the case of a ceramic catalyst holder, in rare cases, the catalyst holder is damaged. That's because Also, 2.5
If the thickness exceeds twice, as described above, not only the workability of assembling becomes extremely poor, but also the ceramic fiber layer is broken. Also, the bulk density of the ceramic fiber when sealed under reduced pressure must be in the range of 0.10 to 0.40 g / cm ³ . If the bulk density is too low, the restoring force of the ceramic fiber is weak, and the catalyst holder dances due to the engine vibration or running vibration of the automobile, the ceramic fiber layer is not only powdered or worn, but also the exhaust gas is reduced by the ceramic fiber. This is because they penetrate the layer. Conversely, if the bulk density is too large, the ceramic fibers themselves will be crushed by the pressure during the pressure assembly in the subsequent step, or the catalyst holder will be damaged or deformed. Next, a catalyst holding body is set inside the fiber seal body, and pressure is applied from above and below the outside of the shell so that the upper shell and the lower shell are brought into close contact with each other, and the outer peripheral portion of the shell is clinched. , And fix with 211 parts with bolts and nuts. Next, as described above, the airtight sheet can be heated and incinerated after the exhaust gas purifying converter is manufactured. Further, even when the exhaust gas purifying converter is mounted on a vehicle or the like, part or all of the airtight sheet may remain. [0015] The ceramic fiber layer of alumina fibers, silica - a material selected from non-woven fabric of alumina textiles
Used. In particular , in consideration of the material cost, the ceramic fiber is provided with an alumina fiber that is more expensive but has higher heat resistance on the catalyst holder side where the temperature is high, and is slightly inferior in heat resistance on the low temperature side on the outer side, but is inexpensive. silica - a two-layer structure in which distribution of the alumina fibers. The airtight sheet is made of silicone resin,
An organic synthetic sheet made of polyvinyl chloride, polyethylene, ionomer resin or the like is used. In particular, it is preferable that the surface of the airtight sheet has good lubricity in order to easily assemble the fiber seal body into the shell. That is, it is preferable to use a material having a low surface friction coefficient for the airtight sheet. From this point, polyvinyl chloride, polyethylene, and ionomer resin are most preferable among the materials of the above-mentioned hermetic sheet. It is also effective to coat the outer surface of the airtight sheet with a lubricating oil or the like to increase lubricity. In the converter for purifying exhaust gas according to the production method of the present invention, a ceramic fiber layer is provided as a seal layer between the catalyst holder and the shell. The ceramic fiber layer is excellent in heat resistance. For this reason, even if this ceramic fiber layer is exposed to exhaust gas, particularly high-temperature lean burn exhaust gas, it can be deformed and deteriorated in quality due to a decrease in expansion pressure like a conventional vermiculite buffer sealing material. Absent. In the manufacturing method of the present invention, the ceramic fiber layer in the converter for purifying exhaust gas is covered with an airtight sheet, and the inside of the airtight sheet is in a reduced pressure state. Therefore, the thickness of the ceramic fiber is reduced, and the thickness becomes equal to or larger than the distance between the shell and the catalyst holder by 150%. Therefore, the ceramic fiber layer can be easily and reliably assembled between the shell and the catalyst holder without requiring a complicated process, and can be used during handling and transportation after assembling the exhaust gas purification converter. Even if
The catalyst holder does not move or break in the shell. In this way, the brittle ceramic fiber layer can be easily assembled in the shell without damaging it. As described above, according to the present invention, a converter for purifying exhaust gas in which the seal layer does not deteriorate at high temperatures can be easily assembled at low cost without damaging the seal layer. (Embodiment 1) First, an exhaust gas purifying converter manufactured according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the exhaust gas purifying converter 1 of the present embodiment includes a catalyst holder 4, a shell 2 covering the outside of the catalyst holder 4, and a ceramic fiber layer 31 disposed therebetween. , The ceramic fiber layer 31
And the shell 2 are covered with an airtight sheet 32.
The ceramic fiber layer 31 has a two-layer structure of alumina fibers on the catalyst holder 4 side and silica-alumina ceramic fibers on the shell side. The airtight sheet 32 is made of polyethylene, and the catalyst holder 4 is made of cordierite. Reference numeral 39 denotes a seam generated when the ceramic fiber layer 31 is arranged. The shell 2 includes an upper shell 21 and a lower shell 22. Each of the upper shell 21 and the lower shell 22 is a half-oval shell. At both ends, flanges 210 and 220 having bolt holes 211 are provided. The catalyst holder 4 is a honeycomb body having a lattice cross section. The cross section is an ellipse, and its size is 150 mm in major axis and 100 mm in minor axis. In the converter 1 for purifying exhaust gas of the present embodiment, a ceramic fiber layer 31 is provided between the catalyst holder 4 and the shell 2 as a seal layer. The ceramic fiber layer 31 and the shell 2
Are covered with an airtight sheet 32. Thus, the ceramic fiber layer 31 is excellent in heat resistance, but is brittle, weak in friction and the like, and can be assembled in the shell 2 without damaging the ceramic fiber layer 31. For this reason, even if the ceramic fiber layer 31 of this example is exposed to exhaust gas, particularly high-temperature lean burn exhaust gas, the ceramic fiber layer 31 does not deform and deteriorate in quality due to a decrease in expansion pressure like a conventional vermiculite buffer seal material. Never wake up. Next, a method of manufacturing the converter for purifying exhaust gas according to the present invention will be described. As shown in FIG. 2A, a plate-like ceramic fiber 31 having a short side of 100 mm, a long side of 200 mm, a thickness of 25 mm, and a bulk density of 0.10 g / cm ^3.
Prepare The ceramic fiber 31 is provided at its end with a concave engaging portion 310 and a convex engaging portion 311 meshed with the concave engaging portion 310. On the other hand, as shown in FIG. 2B, a heat sealing film 32 made of polyethylene is prepared. Next, as shown in FIG. 3A, the shell 2 is placed outside the ceramic fiber 31. Next, as shown in FIG. 3B, the heat-sealing film 32 is sandwiched between the ceramic fiber 31 and the shell 2 from the outside, and the inside is decompressed. Thereby, the ceramic fiber 31 has a thickness of 10 mm and a bulk density of 0.25 g /
cm ³ . Thereafter, the outside of the fiber seal 3 was coated with lubricating oil. Next, as shown in FIG. 3C, the catalyst holder 4 is placed on the upper part of the fiber seal 3 composed of the lower shell 22. At this time, the concave engaging portions 310 and the convex engaging portions 311 at both ends of the ceramic fiber layer 31 are engaged with each other. Further, the fiber seal 3 composed of the upper shell 21 is placed on the catalyst holder 4.
Next, the upper shell and the lower shell 22 are pressurized, and then a bolt is inserted into a bolt hole of the flange to fix the upper shell 21 and the lower shell 22 (FIG. 1). As described above, according to the present embodiment, the ceramic fiber layer 31 can be easily mounted between the shell 2 and the catalyst holder 4 without damaging the ceramic fiber layer 31. Can be easily manufactured. At this time, the clearance between the catalyst holder 4 and the shell 2 is 6 mm.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional perspective view of an exhaust gas purification converter manufactured according to the present invention. FIG. 2 is an explanatory diagram of a manufacturing method according to the first embodiment. FIG. 3 is an explanatory view of the manufacturing method following FIG. 2; FIG. 4 is a longitudinal sectional view of a conventional converter for purifying exhaust gas. FIG. 5 is a configuration diagram of a conventional buffer sealing material of an exhaust gas purification converter. FIG. 6 is an explanatory view relating to mounting of a conventional cushioning sealing material. FIG. 7 is an explanatory view of a problem following the mounting of the cushioning seal material, following FIG. 6; [Description of Signs] 1: Exhaust gas purification converter 2: Shell 21:
Upper shell 22: Lower shell 3: Fiber seal
31: Ceramic fiber layer 32: Airtight sheet
4: Catalyst holder 33: Hot melt portion of airtight sheet

Claims (1)

(57) [Claim 1] To a converter for purifying exhaust gas for automobiles, comprising a catalyst holder, a shell covering the outside of the catalyst holder, and a ceramic fiber layer disposed therebetween . of <br/> to have you to the mounting method of the insulating sealing member, arranged alumina fibers of the nonwoven fabric in a portion of the catalyst holder side, shea
Placing a non-woven fabric of silica-alumina fiber on the side of the well
The double structure of the plate-shaped or cylindrical Jose La Mick fiber nonwoven fabric comprising, after placement on the inner side of the shell, thereof shell
And place in in the airtight sheet the fiber non-woven fabric to Rabbi
Or, after the heat sealed pinched by thermal fusion film, by reducing the internal pressure, the bulk density of the ceramic fiber layer with a 0.10 to 0.40 g / cm ^3, of the ceramic fiber nonwoven fabric The thickness is set to 1.0 of the clearance after assembling the catalyst holder and the shell.
Until 2.5 times the thickness of the reduced dense closed, then vacuum sealed the ceramic fiber nonwoven
The catalyst holder is applied to the inside of a cloth , and
Mounting method insulation seal material to automobile exhaust gas purifying converter characterized by assembling by pressurizing the upper and lower shell located.