JP3459937B2 - Metal carrier for exhaust gas purification catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
Metal catalyst carrier for exhaust gas purification catalyst that purifies exhaust gas
In particular, it is concerned with improving the structure of metal carriers.
is there. [0002] 2. Description of the Related Art For example, exhaust gas from an automobile engine is purified.
As a catalyst for purifying exhaust gas
Or a supporting layer made of activated alumina etc. on a metallic honeycomb body.
Formed and a catalytic metal such as platinum or rhodium
What is carried is often used. However, catalyst gold
The genus does not provide catalytic activity below about 300 ° C.
There is a reality that it is. Therefore, immediately after starting the engine, etc.
Means that the temperature of the catalyst carrier is low, and
Most of the harmful substances are purified until heated up.
There was a problem of being discharged as it was. In order to improve such a problem, a
Made of metal with higher thermal conductivity and better temperature rise characteristics than mix
Metal carriers are becoming mainstream. Also, for example,
No. 63-141632 and Japanese Utility Model No. 2-83320
According to reports, small-sized metal honeycombs
A cam body is placed, and a ceramic or meta
Discloses a tandem-type carrier structure with a honeycomb body made of
Have been. Thus, the heat capacity of the carrier on the upstream side is reduced.
To quickly raise the temperature of the carrier on the upstream side
be able to. In addition, catalyst metal with high low-temperature activity is
Improve the degree of freedom in catalyst design, such as by supporting a large amount on a carrier
You. [0004] By the way, the exhaust gas passes through the flow path on the outer peripheral side of the flow path.
Due to heat radiation from the wall, etc.
There is a temperature distribution where the temperature is high. And the temperature
At the high center of the axis, the catalytic reaction proceeds and generates heat of reaction.
The temperature difference between the shaft center and the outer periphery
U. Therefore, even with metal carriers, the temperature rises at the center of the shaft.
Excellent characteristics, but the temperature rise is slow on the outer circumference,
That the initial purification performance varies depending on the direction
There is. Accordingly, Japanese Utility Model Application Laid-Open No. 63-63521 discloses
Has multiple metal honeycomb bodies separated by an interval
And the direction of the flow path of each honeycomb body is different from each other.
A tandem-type carrier is disclosed. this
The carrier has a space between each divided carrier.
Therefore, the exhaust gas rectified by the former divided carrier
The mixture is stirred and mixed in turbulence, and the adjacent divided carriers
Since the flow paths are different from each other, stirring and mixing are further improved.
Promoted. Therefore, the exhaust flowing into the downstream split carrier
Since the gas temperature becomes uniform, variations in purification performance
Is prevented. [0006] However, the above-mentioned tan
In the dem-type carrier structure, the space between the divided carriers
Exhaust gas comes into direct contact with the outer cylinder,
There is a problem that heat dissipation is large. Also, turbulence in the space
High temperature exhaust gas at the shaft center shifts to the outer periphery
Therefore, the temperature of the exhaust gas on the outer peripheral side rises and consequently
It is to promote heat radiation to the outer cylinder. Therefore
Heat loss occurs, and the temperature rise performance of the downstream carrier is not improved
This hindered improvement in purification performance. [0007] The temperature rise of the divided carrier on the downstream side is caused by exhaust gas.
Heat only by the heat of catalytic reaction.
The heat of the upstream divided carrier itself rises and rises in the downstream divided carrier.
Little contribution to temperature. Not only that, but also the insulation of the space
Due to the action, the temperature of the upstream split carrier rises too much,
There is also a problem that it is easily deteriorated. More honeycombs
Body needs to be mounted inside the outer cylinder, which is a problem in productivity
There is. It is assumed that the problem of productivity is solved.
, A state in which multiple corrugated sheets are arranged on a single flat plate at intervals
Is also disclosed in the publication. But this
In this structure, only the flat plate is wound in a roll shape
Since the gas is difficult to move in the radial direction, the effect of turbulence
Difficult to obtain. Heat on the upstream side is transferred to the downstream side via the flat plate.
Because of heating, the effect of the split carrier is reduced by half. further
Large heat capacity. For these reasons, the initial purification performance
There is a problem that it is inferior. The present invention has been made in view of such circumstances.
It reduces exhaust heat to the outer cylinder and
The flow can be made turbulent and the heat capacity is reduced to improve the temperature rise characteristics.
The purpose is to make it better. [0010] [MEANS FOR SOLVING THE PROBLEMS]
Ming's metal carrier for exhaust gas purification catalysts consists of flat and corrugated plates.
The honeycomb body wound in a roll shape
Metal carrier for exhaust gas purification catalyst, comprising an outer cylinder
, At least one of the flat plate and the corrugated plate
Extends substantially in the winding direction while tilting with respect to the longitudinal direction of the plate
Through hole grouponlyHaving a plurality of honeycombs adjacent to each other in the honeycomb body.
Cam passage spirally communicates through through holes, Through-hole group
Extends spirally from the inner circumference to the outer circumference of the honeycomb bodyThis
And features. The diameter of the through-holes constituting the through-hole group is 1 to 5
mm is preferred. If the diameter is less than 1 mm, it is difficult to form through holes.
If the diameter exceeds 5 mm, the high-temperature exhaust gas
Is too large to move to the outer circumference.
Not good. [0012] According to the metal carrier of the present invention, a plurality of honeycomb passages are provided.
Through the group of through holesSpirallyCommunicating. Therefore
Exhaust gas enters and exits through the through hole,
Turbulence in the exhaust gas flow
Can be achieved. And the upstream and lower by the through-hole group
Adjusts the heat transfer area on the upstream side, so that the calorific value on the upstream side is
By controlling the amount of heat deprived, the upstream temperature rise and
It controls the temperature rise characteristics on the downstream side. Also came out from the upstream side
Adjusts the degree to which exhaust gas diffuses before flowing downstream
are doing. That is, the larger the number of through holes, the more downstream
The amount of heat loss is small, the temperature rise on the upstream side is good, and
The longer the hole is drilled, the more the exhaust gas that has exited the upstream
And the peak temperature of the exhaust gas decreases. For this reason practical
Above, through holes are provided under appropriate conditions in consideration of the above phenomenon
Need to be Further, a space like a conventional tandem-type carrier is provided.
No heat radiation to the outer cylinder
Will be done promptly. [0014] According to the metal carrier of the present invention,
The temperature rise on the upstream side at the beginning of startup is fast, and the temperature on the downstream side is also fast.
It rises quickly. Therefore, the initial purification performance is improved,
Also, since local overheating is prevented, deterioration is prevented and long-term
Can be used for a while. Also, using multiple honeycomb bodies
Can achieve the same effect as a tandem-type carrier without
It has excellent productivity. [0015] [Embodiment]Reference Example, Example, and Comparative ExampleMore specific
Will be explained. (Reference example1) FIG. 1 shows one embodiment of the present invention.Reference example1 shows a metal carrier. This meta
The honeycomb carrier has a honeycomb body 1 and an outer housing for housing the honeycomb body 1.
And a cylinder 2. As shown in FIG. 2, the honeycomb body 1 is made of Fe
Heat resistance of -20Cr-5Al-REM (Y, La etc.)
100mm wide foil formed from steel to a thickness of 50μm
And a flat plate 10 formed by corrugating the flat plate 10
And the corrugated sheet 11 is overlapped.
It is formed by winding into a roll with a diameter of 90 mm.
You. The central part in the width direction of the flat plate 10 and the corrugated plate 11
Has a large number of through-holes 12 in a 20 mm wide strip shape.
It is entirely drilled from one end to the other. Therefore gain
The width of the central portion 16 in the length direction is
A group of through-holes 12 from the outer periphery to the center at a portion of 20 mm
Exists. The honeycomb body 1 includes a flat plate 10 and a corrugated plate 11.
After being wound with overlapping, ferrite alloy etc.
Is inserted into the outer cylinder 2 having a thickness of 1.5 mm. And
4 × 10 ^-FourHeated at 1300 ° C for 60 minutes under vacuum of Torr
Diffusion bonding and brazing bonding
Has been In the case of brazing, supply coating of brazing material
Cloth was performed by a known method. BookReference exampleMetal support is precious for catalysts such as platinum
After the metal is supported, the exhaust gas is directed in the axial direction as shown in FIG.
Is arranged as a catalytic converter so that it is parallel to the
You. Here, the upstream portion 14 is a central portion having many through holes 12.
The portion 16 is continuous with the downstream portion 15 through the portion 16. Accordingly
The heat insulation effect of the exhaust gas in the through hole 12 causes
The heat of the minute 14 is on the downstream side compared to the whole carrier
The heat is not easily transferred to the portion 15, and the upstream portion 14 is quickly
Raise the temperature. However, the flat plate 10 and the wave
Since the plate 11 is continuous, a tandem type having a space is provided.
The heat transfer is performed faster than the carrier, and the downstream portion 15
Is also excellent in temperature rise characteristics. In the central portion 16, as shown in FIG.
The plurality of honeycomb passages 13 communicate with each other through the through holes 12.
I have. Therefore, the exhaust gas flowing in the honeycomb passage 13
Can move in and out of the through-hole 12, and the temperature of the
Uniformity can be achieved. Thus, the downstream portion 15
And the purification performance of the downstream portion 15 becomes uniform.
Can be prevented from being locally varied. Exhaust gas that comes into direct contact with the outer cylinder 2
The volume is extremely high compared to a conventional tandem carrier with a space.
Less. Therefore, unnecessary heat radiation to the outer cylinder 2 is suppressed.
Thus, the temperature rise of the downstream portion 15 is further promoted. Sand
ChimotoReference exampleAccording to the metal carrier of FIG.
Especially excellent in temperature characteristics. To demonstrate this, a bookthree
ExampleActivated alumina support layer is formed on metal carrier
And platinum and rhodium catalyst in the usual manner
Metal as a catalyst for the emission of automobile gasoline engines.
It was attached to the air system. And 30 seconds after starting
The temperature of the central part of the side part 15 was measured, and the results are shown in Table 1.
You. In order to know the influence of the diameter of the through hole 12,
The hole diameter of the through hole 12 is 3 levels of 10mm, 5mm, 1mm
Each form a metal carrier, and for each
The temperature was measured. (Comparative Example 1) Except that it does not have a through hole 12Reference exampleMetal similar to
Choose a carrier and do the sameReference exampleAt the same position as the measurement position
Table 1 shows the results of measuring the temperature. (Comparative Example 2) A pair of 50 mm long honey made of the same material as in Comparative Example 1.
A tandem type with cam bodies arranged at intervals of 20 mm
Select the carrier and set the temperature at the center of the downstream honeycomb body in the same manner.
Table 1 shows the measurement results. [0022] [Table 1]From Table 1, it has a through-hole 12.Reference example1 carrier is a through hole
Excellent in temperature rise characteristics of the downstream part compared to the comparative example without
It is clear that Also, the larger the hole diameter,
It can also be seen that the effect tends to increase. On the other hand, the carrier of Comparative Example 1
Inferior temperature characteristics are caused by large heat capacity.
It is thought that it causes. In addition, the tandem bearing of Comparative Example 2
In the body, the presence of the space prevents heat transfer to the downstream carrier
And the large heat dissipation from the outer cylinder
It is considered to be. In the above reference example, the group of through holes 12 is
It was provided in the center part of the flat plate 10 and the corrugated plate 11 in a strip shape.
However, a plurality of lines may be provided in parallel.(Example 1) The metal carrier of one embodiment of the present invention is Shown in FIG. 4 or FIG.
So that it is inclined with respect to the longitudinal direction of the flat plate and the corrugated plate.
ToA group of through holes 12 is provided.In these cases, the through holes 12
It is difficult to distinguish upstream and downstream by groups.
However, the band of the group of through-holes 12 is spirally formed on the metal carrier.
The effect of turbulence is further improved. (Reference Example 2) FIG. 6 shows a metal carrier of a second reference example. This metal bearing
In the body, the outer diameter D₁= 86mm, length B₁= 100mm
The honeycomb body 1 has a thickness t_Two= 2mm, outer diameter D_Two= 90m
m, length B_Two= 100 mm. The honeycomb body 1 is made of an Fe-20Cr-5Al-based material.
A flat plate 10 having a thickness of 50 μm and a width of 100 mm;
0 is corrugated to wave height 1.2mm and wave pitch 2.4mm
Formed corrugated sheet 11 wound around center axis
Have been. For flat plate 10 and corrugated plate 11 before processing
Is b₁= 20 mm, diameter d₁
= 1 mm through holes 12 with pitch p as shown in FIG.₁= 3m
m in the longitudinal direction. Therefore, the through hole group
In the existing position, the cross-sectional area of the flat plate and corrugated plate is about 33 in the circumferential direction.
% Has been reduced. When the exhaust gas is directed in the direction of A,
Into the exhaust system of the engine so that
One parameter from the entrance at the center of the metal carrier as a parameter of degree
0mm position X₁And the position X at 40 mm_TwoHeating in
The situation was measured and evaluated. For comparison, as shown in FIG.
A conventional tandem carrier having an upstream carrier 3 and a downstream carrier 4
Attach the body in the same way,Reference exampleEquivalent to the metal carrier of
Place (X₁, X_Two) Was compared. engine
Table 2 shows the temperature measurement results 15 seconds and 30 seconds after the start. [0026] [Table 2]As mentioned above, the bookReference exampleTemperature measuring point X on the upstream side of the metal carrier
₁Has a slower heating rate than the tandem carrier,
Hot point X_TwoTemperature rise is much better and after 30 seconds the purification performance
The temperature that can be used has been reached. On the other hand, tandem carriers
In this case, the temperature of the upstream carrier 3 rises quickly, but the exhaust gas is purified.
The temperature rise of the downstream carrier 4 which affects
Has not reached the purifying temperature. [0027] [0028]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a metal carrier according to a reference example of the present invention, partially cut away. FIG. 2 is an exploded perspective view of the honeycomb body used in FIG. FIG. 3 is an enlarged sectional view of a main part of FIG. FIG. 4 is a plan view of a flat plate of the metal carrier of Example 1. FIG. 5 is a plan view of a flat plate, showing another mode of the first embodiment. FIG. 6 is a cross-sectional view of a metal carrier of Reference Example 2. FIG. 7 is a plan view of a main part of a flat plate used for a metal carrier of Reference Example 2. FIG. 8 is a sectional view of a conventional tandem carrier. [Description of Signs] 1: Honeycomb body 2: Outer cylinder
10: flat plate 11: corrugated plate 12: through hole
13: honeycomb passage 14: upstream portion 15: downstream portion
16: Central part

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshikazu Nakagawa 5-3 Tokai-cho, Tokai-city, Aichi Prefecture Inside Nippon Steel Corporation Nagoya Works (56) References JP-A-63-134061 (JP, A JP-A-3-174221 (JP, A) JP-A-4-260443 (JP, A) JP-A-2-273546 (JP, A) JP-A 63-141633 (JP, U) JP-A 63-141633 126029 (JP, U) JP-A-3-26321 (JP, U) JP-A-4-53448 (JP, U) WO 91/001178 (WO, A1) (58) Fields investigated (Int. Cl. ⁷⁾ B01J 21/00-38/74 B01D 53/94

Claims (1)

(57) [Claim 1] A metal carrier for an exhaust gas purifying catalyst, comprising a honeycomb body wound on a flat sheet and a corrugated sheet and wound into a roll, and an outer cylinder holding the honeycomb body. Wherein at least one of the flat plate and the corrugated plate has only a group of through holes extending in a substantially winding direction while being inclined with respect to the longitudinal direction of the flat plate and the corrugated plate, and is adjacent to the honeycomb body. A plurality of honeycomb passages spirally communicate with each other through the through hole group, and the through hole group
A metal carrier for an exhaust gas purifying catalyst, which spirally extends from an inner periphery to an outer periphery of a honeycomb body .