JP2583377Y2 - Flat metal carrier - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat metal carrier for purifying exhaust gas discharged from an internal combustion engine such as an automobile engine.

[0002]

2. Description of the Related Art Conventionally, ceramic metal carriers have been used in catalytic converters for purifying exhaust gas. However, in recent years, the use of metal carriers has increased due to heat resistance, low pressure loss and mountability. I have.

The metal carrier is formed by laminating a flat foil made of a corrosion-resistant and heat-resistant metal such as stainless steel having a thickness of about 50 μm and a corrugated corrugated flat foil in a spiral shape or alternately. Thus, a honeycomb body is formed and housed in an outer cylinder made of a corrosion-resistant and heat-resistant metal such as stainless steel. In this case, the inside of the honeycomb body and the connection between the honeycomb body and the outer cylinder are joined by known techniques such as brazing, electron beam, laser beam, resistance welding, diffusion bonding, or the like. The metal carrier is loaded with a catalyst for purifying exhaust gas such as platinum, palladium, and rhodium, and then used, for example, in an exhaust gas system of an automobile engine.

[0004] Since the metal carrier is used in a narrow place such as near the engine or under the floor, the cross-sectional shape of the metal carrier is circular, elliptical, or flat type composed of a parallel part and an arc part according to the place of use. There is. Among them, a flat metal carrier composed of an elliptical or parallel portion and an arc portion is used in a place where the height in the vertical direction is restricted, such as under the floor.

[0005] Such a metal carrier used under the floor is also subjected to severe thermal cycling or severe vibration due to high-temperature exhaust gas from the engine, so that a joint inside the honeycomb body or a joint between the honeycomb body and the outer cylinder is formed. Is easily damaged, and it is important to ensure durability. The flat metal carrier composed of an elliptical or parallel part and an arc part used under the floor is connected to a pipe-shaped exhaust pipe as shown in FIG. Is connected. The exhaust gas flows from the direction of arrow A into the flat metal carrier 3 composed of an elliptical or parallel portion and an arc portion through the entrance cone 1 and exits from the exit cone 2. During this time, the exhaust gas is purified by the catalyst carried on the honeycomb body 4.

[0006] In a flat metal carrier composed of an elliptical or parallel portion and an arc portion, the exhaust gas inflow velocity distribution is such that a large amount of exhaust gas passes through the short diameter side to the vicinity of the outer periphery at a high speed, but the long diameter side. Then, the speed decreases toward the outer periphery, and the amount of exhaust gas per unit area decreases. As a result, the temperature of the honeycomb body on the minor diameter side is high and the change is large. On the other hand, on the long diameter side, the temperature of the honeycomb body is relatively low, and the change is mild.

Utilizing this phenomenon, Japanese Patent Laid-Open No. 4-18083
No. 8 proposes a method in which a joining portion of a honeycomb body or a joining portion of a honeycomb body and an outer cylinder is limited to a long diameter side. However, in the case of a flat metal carrier composed of an elliptical or parallel part and an arc part, the outer cylinder swells during use because the radius of curvature is large or linear on the minor diameter side, and the honeycomb body and Separation and gaps occur. as a result,
There is a problem that unpurified raw gas passes through the metal carrier, and it is necessary to restrict the use conditions such as restricting the exhaust gas temperature.

[0008]

SUMMARY OF THE INVENTION According to the present invention, raw gas flows out by preventing the outer cylinder of a flat metal carrier constituted by an elliptical or parallel portion and an arc portion from being deformed and separated from the honeycomb body. It is intended to provide a metal carrier that can prevent the occurrence of the metal carrier.

[0009]

SUMMARY OF THE INVENTION According to the present invention, in a flat metal carrier having an elliptical cross section or a parallel portion and an arc portion, a honeycomb body is joined to a short diameter portion or the whole honeycomb body, and the honeycomb body is joined to the honeycomb body. Joining with outer cylinder at short diameter
At the same time, the joint is determined by the joint width (d) in the axial direction and
D / L = 1/10 to 1/2 in ratio to the length of the honeycomb body (L)
The present invention relates to a flat metal carrier characterized by the following.

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a three-dimensional cross-sectional view showing a joint portion of a flat metal carrier having an elliptical or parallel portion and an arc portion according to the present invention. The metal carrier 3 is formed by winding or laminating a flat foil 5 of an alloy foil having a thickness of about 50 μm, which is resistant to oxidation and heat, and a corrugated corrugated foil 6. It is composed of an outer cylinder 7 to be stored. This external shape is an ellipse having a different outer diameter in the minor axis direction of the cross section and the major axis direction perpendicular thereto, or a flat type constituted by a parallel portion and an arc portion.

The hatched portion of the honeycomb body 4 indicates the joining portion 8 inside the honeycomb body, but the entire short diameter portion is joined. The joint 9 indicates a joint between the honeycomb body 4 and the outer cylinder 7. That is, the joining portion 8 of the honeycomb body is
The outer cylinder 7 is joined to the outer cylinder 7 at a short diameter joint 9 between the outer cylinder 7 and the outer cylinder 7.

FIG. 2 shows the appearance of the honeycomb body 4 from which the outer cylinder 7 has been removed, and shows a joining portion 9 to be joined to the outer cylinder 7. Therefore, the honeycomb body 4 and the outer cylinder 7
By joining, even if the short diameter side of the outer cylinder 7 is deformed during use and swells outward, the outer cylinder 7 is retained by the joint 9 and the joint 8 of the honeycomb body 4 to prevent deformation and to generate a gap. Is prevented.

In the present invention, the connection between the honeycomb body 4 and the outer cylinder 7 is performed on the short diameter side as described above . The joint 9 between the honeycomb body 4 and the outer tube 7 according bonding width in the axial direction (d) is a carrier size, the mounting state and the use state, the ratio of the length of the honeycomb body 4 (L) d / 1/10 in L
As a ~ 1/2 and by selecting the bonding position central responsible body, the exit side or entry side, 850 ° C.
Can withstand even the endurance test . On the other hand, the honeycomb body 4
It is more effective to join not only the short diameter side but also the entire honeycomb body.

[0014]

[ Example 1] In the cross section, the major axis is 150 mm, the minor axis is 100 mm, and the length is 1 mm.
The conventional flat metal carrier having a thickness of 00 mm and the metal carrier according to the present invention were compared. The configurations and specifications of the honeycomb body and the outer cylinder are as follows.

Flat foil: Ferritic stainless steel foil, thickness 50 μm Wave foil: Ferrite stainless steel foil, thickness 50 μm, wave height 1.25 mm, pitch 2.54 mm Outer cylinder: ferrite stainless steel, plate thickness 2 mm, major axis 150 mm, Honeycomb 100 mm, length 100 mm Honeycomb dimensions: major 146 mm, minor 96 mm, length 10
0 mm Joining method: The honeycomb body was diffusion-bonded, and the honeycomb body and the outer cylinder were brazed. Conventional carrier bonding position: As shown in the schematic diagram of FIG. 4 , the honeycomb body is formed by diffusion bonding only the hatched portion 10 of the circular arc portion in the axial direction, and the central portion of the circular arc portion 1 between the honeycomb body and the outer cylinder.
1 is brazed in the axial direction in a range of 50 mm in width. Bonding position of the carrier of the present invention: As shown in the schematic view of FIG. 3 , the honeycomb body is formed by diffusion bonding only the hatched portion 12 of the parallel portion along the entire length in the axial direction, and the central portion 13 of the parallel portion between the honeycomb body and the outer cylinder. Is brazed in a range of 50 mm in width in the axial direction .

[0016] The above two flat metal carriers are displaced by a displacement of 200
Mounted on a 0cc engine, one cycle heats 850 ° C x
A thermal cycle test in which cooling was performed at 150 ° C. for 10 minutes for 10 minutes was performed at 500 cycles. As a result, in the conventional metal carrier, the outer cylinder on the shorter diameter side swelled by 4 mm, and a gap having an average of 2 mm on one side was generated between the outer surface of the honeycomb body and the inner surface of the outer cylinder, and unpurified raw gas passed. On the other hand , the maximum outer cylinder swelling of the carrier of the present invention is on the short diameter side, the amount is as small as 0.8 mm, there is no generation of a gap between the outer cylinder and the honeycomb body, and it is possible to purify the entire amount without outflow of raw gas. As a result, the function as a catalytic converter could be achieved. 3 and 4 show the case where the outer cylinder is removed .
Shows the appearance of the honeycomb body (not shown in the flat foil and corrugated foil)
You .

[Embodiment 2] A method using a honeycomb body having the dimensions described in Embodiment 1 and an outer cylinder is used.
For the tall carrier, as shown in the upper part of FIG.
The body joint is diffusion-bonded over the entire length of the parallel part (Hatchin
Part), the honeycomb body-outer cylinder joint is at the center of the parallel part
As indicated by hatching, the joint width (d) in the axial direction
The joining was performed while changing the ratio d / L to the length (L) of the honeycomb body.
The various metal carriers manufactured in this manner were subjected to a displacement of 200
Heating mounted on a 0cc engine and changing the heating temperature (× 1
0 minutes)-Thermal cycle that repeats cooling (150 ° C x 10 minutes)
900 cycles, and observe the blister of the outer cylinder.
Was. The swelling became 1 mm or more and the unpurified exhaust gas leaked
The temperature at that point was taken as the endurance temperature. FIG. 6 shows the results. FIG.
As is clear from the above, d / L is in the range of 0.1 to 0.5,
In other words, the conventional reference temperature (8
High temperature endurance temperature exceeding 850 ℃
Above), indicating that excellent durability was obtained.

[0018]

As described above, according to the present invention, the deformation of the outer cylinder of the flat metal carrier composed of the elliptical or parallel portion and the arc portion is reduced, and the gap between the outer surface of the honeycomb body and the inner surface of the outer cylinder is reduced. Therefore, the outflow of unpurified raw gas can be prevented, and the effect is great.

[Brief description of the drawings]

FIG. 1 is an external view of a cross section of a part of the metal carrier of the present invention.

FIG. 2 is an external view showing an example of the honeycomb body of the present invention.

FIG. 3 is a schematic view showing a joining position of the honeycomb body of the present invention.

FIG. 4 is a schematic view showing a joining position of a conventional honeycomb body.

FIG. 5 is an explanatory view of mounting a metal carrier.

FIG. 6 is a diagram showing a relationship between a ratio d / L of an axial joint width (d) of a honeycomb body-outer cylinder joint and a honeycomb body length (L) and an endurance temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inlet cone 2 Outlet cone 3 Metal carrier 4 Honeycomb body 5 Flat foil 6 Corrugated foil 7 Outer cylinder 8 Honeycomb joint part 9 Short diameter joint part between honeycomb body and outer cylinder 10 Arc joint part of honeycomb body 11 Arc junction between honeycomb body and outer cylinder 12 Parallel junction of honeycomb body 13 Parallel junction between honeycomb body and outer cylinder A Exhaust gas inflow direction

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-180838 (JP, A) JP-A-3-165842 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01N 3/28 301-311 B01J 35/04 B01D 53/00-53/96

Claims (1)

(57) [Scope of request for utility model registration] In a flat metal carrier having a cross section composed of an elliptical or parallel portion and an arc portion, a honeycomb body is joined at a short diameter portion or the whole honeycomb body, and a honeycomb body and an outer cylinder are joined at a short diameter. And the joint is
Of the joint width (d) and the honeycomb body length (L) in the direction
Wherein d / L = 1/10 to 1/2 .