JP6367729B2 - Honeycomb body and catalyst carrier - Google Patents

Description

  The present invention relates to a honeycomb body for exhaust gas purification and the like.

  A catalyst carrier having a honeycomb structure carrying a catalyst is installed in an exhaust gas exhaust path for exhaust gas exhausted from an engine of an internal combustion engine such as an automobile or various mechanical equipment for the purpose of purifying the exhaust gas. The exhaust gas contains CO, HC, and NOx, and these gases are purified by contact with the catalyst. Examples of indexes for evaluating the purification performance of the catalyst carrier include T50 and T80.

  T50 is the temperature when the gas concentration of the exhaust gas is reduced by half due to catalytic action, and can be used to evaluate the purification performance at the beginning of exhaust gas inflow (hereinafter referred to as light-off performance). That is, the purification performance at the initial stage of exhaust gas inflow improves as T50 decreases. T80 is the temperature when the gas concentration of the exhaust gas is reduced by 80% due to catalytic action, and can be used to evaluate the purification performance in a steady state (hereinafter referred to as steady performance) after a predetermined time has passed since the exhaust gas flowed. That is, the steady performance is improved as T80 is lowered.

  Moreover, a pressure loss is generated by arranging the catalyst carrier in the discharge path, and the vehicle output is reduced by increasing the pressure loss. For this reason, the catalyst carrier is also required to have a low pressure loss.

  Patent Document 1 discloses that a ribbon-shaped corrugated sheet made of metal foil and a flat plate are wound in multiple layers to form a roll-shaped honeycomb structure inserted into an outer cylinder, and a catalytic substance adheres to the corrugated sheet and the flat plate. A catalyst carrier for purifying exhaust gas, wherein the corrugated plate has a partially different wave phase before and after the wound axial direction. Is disclosed.

  The catalyst carrier of Patent Document 1 has a channel in which the phases of the waves arranged in the axial direction are shifted (offset), and there is a constant channel without changing the phase. The occupying ratio is 50% to 95% of the whole (see paragraph 0017 of the specification). Further, the phase change point in the phase-shifted flow path is considered to be approximately the center in the axial direction of the catalyst carrier from the front sectional view of FIG.

Japanese Patent No. 4719180

  However, in the catalyst carrier of Patent Document 1, the light-off performance of the catalyst carrier is not sufficient. That is, in the configuration of Patent Document 1, by providing the phase shift portion, the exhaust gas passing through the center of the cell easily passes through the phase change point and then hits the outer wall of the offset downstream cell, thereby being easily purified. However, the light-off performance was not sufficient.

  As a matter of course, it is also important as a function of the catalyst carrier that the steady performance is high in addition to the light-off performance. Increasing the offset locations can improve the light-off performance and steady performance, but increasing the offset locations will increase the pressure loss.

  Accordingly, an object of the present invention is to provide a catalyst-supporting honeycomb body having high light-off performance and steady performance and low pressure loss.

  In order to solve the above-described problems, a catalyst supporting honeycomb body according to the present invention has the following features: (1) Metal corrugated foils and flat foils are alternately laminated, whereby exhaust gas is exhausted in an axial direction perpendicular to the laminating direction. A honeycomb body for supporting a catalyst in which a plurality of gas conduction paths for conducting gas are formed, wherein at least a part of an entrance side region located on the exhaust gas entrance side from the center in the axial direction of the honeycomb body The offset part from which the phase of the wave which adjoins in a direction mutually differs is provided, The wave foil arrange | positioned at the said offset part is connected without dividing | segmenting in the said axial direction, It is characterized by the above-mentioned.

  (2) The offset portion is configured by arranging a top portion and fin portions having a pair of side sides extending from both ends of the top surface, and phases of the fin portions adjacent in the axial direction are mutually different. Unlikely, the catalyst supporting honeycomb body according to (1), wherein the top surfaces adjacent in the axial direction are partially connected to each other.

  (3) The catalyst supporting honeycomb body according to (2), wherein the offset portion is configured by arranging the fin portions in a staggered manner along the axial direction.

  (4) The catalyst-supporting honeycomb body according to (2), wherein the offset portion is configured by arranging the fin portions in an inclined direction inclined with respect to the axial direction.

  (5) The honeycomb body for supporting a catalyst according to (2), wherein all the fin portions arranged in the offset portion have the same length in the axial direction.

  (6) The catalyst support according to any one of (2) to (5), wherein the pair of side sides are formed in a tapered shape that is separated from each other as the distance from the top surface increases. Honeycomb body.

  (7) A catalyst carrier comprising the honeycomb body according to any one of (1) to (6) and an outer cylinder in which the honeycomb body is accommodated.

  According to the present invention, since the offset portion is provided only in at least a part of the entry-side region, it is possible to provide a catalyst-supporting honeycomb body having high light-off performance and steady performance and low pressure loss.

1 is a schematic view of a catalyst carrier viewed from an axial direction (Embodiment 1). FIG. It is an expanded view in a part of corrugated foil (Embodiment 1). It is a perspective view of the fin F adjacent to the axial direction provided in the offset part S (Embodiment 1). It is the schematic in a part of offset part S seen from the axial direction (Embodiment 1). It is an expanded view in a part of corrugated foil (Embodiment 2). It is the schematic in a part of corrugated foil of Example No.1-No.4 and comparative example No.1-No.10. It is a graph which shows the relationship between the offset position of a fin, and T50 (Example 1). It is a graph which shows the offset position of a fin, and T80 (Example 1). It is the schematic in a part of corrugated foil of Example No.5-No.7 and comparative example No.11-No.13. It is the schematic in a part of corrugated foil of comparative example No.14-No.18. It is a graph which shows the relationship between the offset position of a fin, and T50 (Example 2). It is a graph which shows the relationship between the offset position of a fin, and T80 (Example 2).

(Embodiment 1)
Hereinafter, the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic view of a catalyst carrier as viewed in the axial direction. The normal direction to the paper surface corresponds to the axial direction, and the direction along the paper surface corresponds to the radial direction. FIG. 2 is a development view of a part of the corrugated sheet. The white arrow corresponds to the exhaust gas conduction direction (the axial direction of the honeycomb body), and the hatched portion corresponds to the top surface of the fin F.

  The catalyst carrier 1 includes a honeycomb body 10 and an outer cylinder 20 and is used as a catalytic converter for exhaust gas purification. The catalyst carrier 1 can be disposed, for example, in an exhaust gas path of a vehicle.

  The honeycomb body 10 is configured by overlapping a corrugated foil 30 shown in FIG. 2 and a flat foil 40 (not shown in FIG. 2) and winding them around an axis. The radial cross section of the honeycomb body 10 is formed in a circular shape. As the corrugated foil 30 and the flat foil 40, a metal foil for supporting a catalyst can be used. As the metal foil, various heat-resistant stainless steels containing Al can be used. When carrying a catalyst, a washcoat solution (a solution containing γ-alumina, an additive and a noble metal catalyst as a component) is supplied to the flow path of the honeycomb body 10 and baked by high-temperature heat treatment to be carried on the honeycomb body 10. Can do.

  When the exhaust gas flowing in from the axial one end side of the honeycomb body 10 comes into contact with the wall surfaces of the corrugated foil 30 and the flat foil 40, the exhaust gas is purified by the catalyst material carried thereon.

  With reference to the development view of FIG. 2, an offset portion S is formed on the corrugated foil 30. The offset portion S is provided in at least a part of the entry side region U in the honeycomb body 10. Since it is “at least a part”, all of the entry side region U of the honeycomb body 10 may be the offset portion S. The entry side region U is a region on the exhaust gas entry side when the honeycomb body 10 is equally divided into two in the axial direction. A region other than the offset portion S in the entry side region U is formed by the non-offset portion T.

  The output side region V is entirely constituted by the non-offset portion T. The exit area V is an exhaust gas exit area when the honeycomb body 10 is equally divided into two in the axial direction.

  The configuration of the offset portion S and the non-offset portion T will be described in detail with reference to FIGS. FIG. 3 is a perspective view of fins F adjacent to each other in the axial direction provided in the offset portion S. FIG. The offset portion S is configured by providing a plurality of rows of fin groups in which the fins F are arranged in a staggered manner along the axial direction. That is, two fins F that are axially opposed across one fin F are provided at positions where the phases are the same, and fins F that are adjacent in the axial direction are provided at offset positions where the phases are different from each other. It has been. The number of fin groups arranged can be changed as appropriate according to the size of the installation location. As the number of fin groups arranged increases, the number of windings of the corrugated foil 30 increases, and the diameter of the honeycomb body 10 can be increased.

  Each fin F includes a top surface 101 and a pair of left and right oblique sides 102 and 103 extending from both ends of the top surface 101, and the left oblique side 102 and the right oblique side 103 are separated from the top surface 101. It is inclined in the direction that spreads toward the end. That is, the fin F is formed in a trapezoidal shape when viewed in the axial direction.

  The fins F adjacent in the circumferential direction of the honeycomb body 10 are connected to each other through the continuous portion 104. Specifically, the adjacent fins F in the circumferential direction are connected by connecting lower end portions of the right oblique side 103 of the adjacent one fin F and the left oblique side 102 of the other fin F.

  The top surfaces 101 of the fins F adjacent to each other in the axial direction provided in the offset portion S are connected to each other, and the top surfaces 101 located at the boundary between the offset portion S and the non-offset portion T are also connected to each other. Thereby, since the corrugated foil 30 including the fins F arranged in a staggered pattern becomes a single plate material, the rigidity can be increased.

  That is, when individual fins F are made independent, the fins F may be easily deformed by receiving an external force from the radial direction of the honeycomb body 10. By connecting the top surface 101 of the fin F formed on the corrugated foil 30 in the axial direction, the rigidity against the external force received from the radial direction can be increased. The corrugated foil 30 having the offset structure described above can be manufactured by pressing a stainless steel or the like in which a cut is formed at a planned offset position with a die or a roller having a protrusion corresponding to the fin F. it can. In addition, it is not an indispensable condition to form a notch in the planned offset position. In this case, the corrugated foil 30 may be formed by sandwiching stainless steel using a pair of the above-described molds having protrusions.

  Here, when the dimension in the axial direction of each fin F provided in the offset portion S is a, and the dimension in the axial direction of the entrance region U of the honeycomb body 10 is L1, preferably a ≧ 1 / 50L1. . By setting a ≧ 1 / 50L1, it is possible to suppress pressure loss due to the excessive number of fins F in the offset portion S. The dimension a of each fin F may be the same.

  In the offset portion S, the connecting width A of the fins F adjacent in the axial direction is preferably three times or more the plate thickness of the corrugated foil 30. If the connection width A of the fins F is less than three times the plate thickness of the corrugated foil 30, the rigidity becomes weak and the offset shape may not be maintained because the fins F are displaced.

  Next, the significance of providing the offset portion S will be described with reference to FIG. FIG. 4 is a schematic view of a part of the offset portion S viewed from the axial direction. Fins F (hereinafter referred to as fins Fi) located on the exhaust gas inlet side in the axial direction are indicated by solid lines, and fins F (hereinafter referred to as fins Fo) located on the exhaust gas outlet side of the fins Fi are indicated by broken lines. Is shown.

  Referring to the figure, out of the exhaust gas flowing into the fin Fi, the exhaust gas passing near the top surface 101 and the hypotenuses 102 and 103 of the fin Fi comes into contact with the catalyst supported on these wall surfaces. The exhaust gas flowing through the center separated from the top surface 101 and the hypotenuses 102 and 103 of the fin F-i becomes difficult to be purified by the fin F-i and becomes a laminar flow and flows into the fin F-o.

  Here, when the fins Fi are continuous to the exit end of the honeycomb body 10 (that is, when all of the honeycomb bodies 10 are configured by the non-offset portions T), the center of the fins Fi is measured. The passing exhaust gas may be discharged from the honeycomb body 10 in an insufficiently purified state. On the other hand, when the offset portion S is provided in the honeycomb body 10 as in the present embodiment, the exhaust gas flowing through the center of the fin Fi is on the left oblique side 102 of the fin FO located downstream of the fin Fi. It becomes easy to purify by contacting. Thereby, purification performance can be improved.

  The present inventors have further found that the pressure loss can be suppressed while improving the light-off performance and the steady performance by providing the offset portion S in at least a part of the entry side region U of the honeycomb body 10. That is, when the offset portion S is provided only in the exit region V of the honeycomb body 10, the light-off performance and the steady performance are not sufficient. Further, when all of the honeycomb body 10 is configured by the offset portion S, not only the pressure loss increases, but also the purification performance cannot be improved by the amount of increase of the offset portions.

(Embodiment 2)
FIG. 5 is a development view of a part of the corrugated sheet of this embodiment. The white arrow corresponds to the exhaust gas conduction direction (the axial direction of the honeycomb body), and the hatched portion corresponds to the top surface of the fin F. In addition, the same code | symbol is attached | subjected to the element which has the same function as Embodiment 1. FIG.

  With reference to the development view of FIG. 5, an offset portion S is formed on the corrugated foil 30. The offset portion S is provided in at least a part of the entry side region U in the honeycomb body 10. Since it is “at least a part”, all of the entry side region U of the honeycomb body 10 may be the offset portion S. The entry side region U is a region on the exhaust gas entry side when the honeycomb body 10 is equally divided into two in the axial direction. A region other than the offset portion S in the entry side region U is formed by the non-offset portion T.

  The output side region V is entirely constituted by the non-offset portion T. The exit area V is an exhaust gas exit area when the honeycomb body 10 is equally divided into two in the axial direction.

  The offset portion S is configured by providing a plurality of rows of fin groups in which the fins F are arranged in an inclination direction that is inclined with respect to the axial direction. The corrugated foil 30 of this embodiment can be manufactured by pressing a flat foil with a mold or a roller provided with a protrusion corresponding to the shape of the corrugated foil 30. The number of fin groups arranged can be changed as appropriate according to the size of the installation location. As the number of fin groups arranged increases, the number of windings of the corrugated foil 30 increases, and the diameter of the honeycomb body 10 can be increased. Since the shape of each fin F is the same as that of the first embodiment, the description will not be repeated.

  Even in the configuration of the present embodiment, the exhaust gas path formed by one fin F adjacent in the axial direction and the hypotenuse 102 (103) of the other fin F are arranged at positions overlapping in the axial direction, so Performance can be improved.

  The present inventors have further found that the pressure loss can be suppressed while improving the light-off performance and the steady performance by providing the offset portion S in at least a part of the entry side region U of the honeycomb body 10. That is, when the offset portion S is provided only in the exit region V of the honeycomb body 10, the light-off performance and the steady performance are not sufficient. Further, when all of the honeycomb body 10 is configured by the offset portion S, not only the pressure loss increases, but also the purification performance cannot be improved by the amount of increase of the offset portions.

The effects described in the first and second embodiments will be described in detail with reference to examples.
Example 1
Example 1 corresponds to the first embodiment. Various changes were made to the length and installation position of the offset portion S, and T50 (light-off performance), T80 (steady performance) and pressure loss of the honeycomb body were evaluated. Specifically, the simulated gas is caused to flow through the honeycomb body at SV (space velocity): 100,000 h ⁻¹ , the simulated gas temperature is gradually heated from room temperature using a heater, and the CO conversion rate (%) at each temperature is set. The T50 at which the conversion was 50% and the temperature T80 at 80% were determined from the conversion-temperature curve. As a simulation gas, THC (propane, C ₃ H ₆ ): 550 ppm (1650 ppmC), NO: 500 ppm, CO: 0.5%, O ₂ : 1.5%, H ₂ O: 10%, N ₂ : balance Used to simulate diesel exhaust. FIG. 6 is a schematic diagram of various samples, and Table 1 shows test results and evaluation results thereof.

  Example No. 1 and Comparative Example No. 1 1, the axial dimension of the offset portion S was 8 mm, and the axial dimension of the non-offset portion T was 36 mm. In addition, Example No. 1, the offset portion S is formed from the end portion on the entering side of the honeycomb body 10. 1, the offset portion S was formed from the outlet end portion of the honeycomb body 10. These Example Nos. 1 and Comparative Example No. 1 1, the pressure loss is the same, but both the light-off performance and the steady performance are shown in Example No. 1 was found to be excellent.

Example No. 2 and Comparative Example No. 2, the axial dimension of the offset portion S was 12 mm, and the axial dimension of the non-offset portion T was 32 mm. In addition, Example No. 2, the offset portion S is formed from the end portion on the entering side of the honeycomb body 10. 2, the offset portion S was formed from the outlet end portion of the honeycomb body 10. These Example Nos. 2 and Comparative Example No. 2 and the pressure loss is the same, but both the light-off performance and the steady performance are shown in Example No. 2 was found to be excellent. In addition, Example No. 1 is Comparative Example No. It was found that the light-off performance and the steady performance were excellent despite the fact that there were fewer offset locations than 2.

Example No. 3 and Comparative Example No. 3, the axial dimension of the offset portion S was 16 mm, and the axial dimension of the non-offset portion T was 28 mm. In addition, Example No. 3, the offset portion S is formed from the end portion on the entering side of the honeycomb body 10. 3, the offset portion S was formed from the outlet end portion of the honeycomb body 10. These Example Nos. 3 and Comparative Example No. 3, the pressure loss is the same, but both the light-off performance and the steady performance are shown in Example No. 3 was found to be excellent. In addition, Example No. 2 is Comparative Example No. It was found that the light-off performance and the steady performance were excellent despite the fact that there were fewer offset locations than 3.

Example No. 4 and Comparative Example No. 4, the axial dimension of the offset portion S was 20 mm, and the axial dimension of the non-offset portion T was 24 mm. In addition, Example No. 4, the offset portion S is formed from the end portion on the entering side of the honeycomb body 10. 4, the offset portion S was formed from the outlet end portion of the honeycomb body 10. These Example Nos. 4 and Comparative Example No. 4, the pressure loss is the same, but both the light-off performance and the steady performance are shown in Example No. 4 was found to be excellent. In addition, Example No. 3 is Comparative Example No. Despite the fact that there are fewer offset points than 4, it was found that the light-off performance was excellent and the steady performance was equivalent.

  Comparative Examples No. 5 to No. 8 are those of Example No. 4, the ratio of the offset portion S is gradually increased, and the offset portion S is expanded to the exit region V. The pressure loss increased as the proportion of the offset portion S increased. On the other hand, the light-off performance and the steady performance were hardly improved even when the offset portion S was expanded to the exit side region V.

  That is, as shown in the graphs of FIGS. 7 and 8, the light-off performance and the steady performance are improved in the entrance area U as the proportion of the offset portion S increases. However, even if the offset portion S is increased beyond the entry side region U, the light-off performance and the steady performance are not improved, but may be deteriorated.

  Comparative Example No. 9 was a case where all of the honeycomb body 10 was composed of the non-offset portion T, and although the pressure loss was the smallest, the light-off performance and the steady performance were the lowest. Further, Comparative Example No. 10 was a case where all of the honeycomb body 10 was constituted by the offset portion S, and the pressure loss was the largest, and the light-off performance was equivalent to that of Example No. 4.

  From the above results, it was found that providing the offset portion S in at least a part of the entry-side region U can suppress the pressure loss while improving the light-off performance and the steady performance.

(Example 2)
Example 2 corresponds to Embodiment 2. The same test as in Example 1 was performed using the samples illustrated in the schematic diagrams of FIGS. 9 and 10. Table 2 shows test results and evaluation results.

  Example No. 5 and Comparative Example No. 11, the axial dimension of the offset portion S was 12 mm, and the axial dimension of the non-offset portion T was 32 mm. In addition, Example No. 5, the offset portion S is formed from the end portion on the entering side of the honeycomb body 10. 11, the offset portion S was formed from the outlet end portion of the honeycomb body 10. These Example Nos. 5 and Comparative Example No. 11, the pressure loss is almost the same, but both the light-off performance and the steady-state performance are the same as in Example No. 5 was found to be excellent.

  Example No. 6 and Comparative Example No. 12, the axial dimension of the offset portion S was 16 mm, and the axial dimension of the non-offset portion T was 28 mm. In addition, Example No. 6, the offset portion S is formed from the end portion on the entering side of the honeycomb body 10. 12, the offset portion S was formed from the outlet end portion of the honeycomb body 10. These Example Nos. 6 and Comparative Example No. 12, the pressure loss is the same, but both the light-off performance and the steady performance are shown in Example No. 6 was found to be excellent. In addition, Example No. 5 is Comparative Example No. Despite the fact that there are fewer offset points than 12, it was found that both the light-off performance and the steady performance were excellent.

  Example No. 7 and Comparative Example No. 13, the axial dimension of the offset portion S was 20 mm, and the axial dimension of the non-offset portion T was 24 mm. In addition, Example No. 7, the offset portion S is formed from the end portion on the entering side of the honeycomb body 10. 13, the offset portion S was formed from the exit end of the honeycomb body 10. These Example Nos. 7 and Comparative Example No. 13, the pressure loss is the same, but both the light-off performance and the steady performance are shown in Example No. 7 was found to be excellent. In addition, Example No. 6 is Comparative Example No. Despite the fact that there are fewer offset points than 13, it was found that the light-off performance is almost the same and the steady performance is the same.

  Comparative Examples No. 14 to No. 18 are those of Example No. 7, the proportion of the offset portion S is gradually increased, and the offset portion S is expanded to the exit region V. The pressure loss increased as the proportion of the offset portion S increased. On the other hand, the light-off performance and the steady performance were hardly improved even when the offset portion S was expanded to the exit side region V.

  That is, as shown in the graphs of FIGS. 11 and 12, the light-off performance and the steady performance are improved in the entrance area U as the proportion of the offset portion S increases. However, even if the offset portion S is increased beyond the entry side region U, the light-off performance and the steady performance are not improved, but may be deteriorated.

  From the above results, it was found that providing the offset portion S in at least a part of the entry-side region U can suppress the pressure loss while improving the light-off performance and the steady performance.

(Modification 1)
In the above-described embodiment, the honeycomb body is configured by superimposing the corrugated foil 30 and the flat foil 40 and winding them around the axis. However, the present invention is not limited to this and may have other configurations. . As the said other structure, the structure which prepares the sheet-like corrugated foil 30 and the sheet-like flat foil 40, and overlaps the sheet-like corrugated foil 30 and the sheet-like flat foil 40 alternately may be sufficient.

(Modification 2)
In the above-described embodiment, the fins F are formed in a trapezoidal shape, but the present invention is not limited to this. For example, the fin F may be formed in a rectangular shape by providing a side extending in a direction perpendicular to the top surface 101.

DESCRIPTION OF SYMBOLS 1 Catalyst carrier 10 Honeycomb body 20 Outer cylinder 30 Corrugated foil 40 Flat foil 101 Top surface 102 Left hypotenuse 103 Right hypotenuse 104 Connection part

Claims (7)

A honeycomb body for supporting a catalyst having a plurality of gas conduction paths for conducting exhaust gas in an axial direction perpendicular to the lamination direction by alternately laminating metal corrugated foils and flat foils,
At least a part of the entrance side region located on the exhaust gas entrance side from the center in the axial direction of the honeycomb body is provided with offset portions having mutually different phases of waves in the axial direction,
The honeycomb body for supporting a catalyst, wherein the corrugated foils arranged in the offset portion are connected without being divided in the axial direction. The offset portion is configured by arranging a fin portion having a top surface and a pair of sides extending from both ends of the top surface,
The phases of the fin portions adjacent in the axial direction are different from each other,
The honeycomb body for supporting a catalyst according to claim 1, wherein the top surfaces adjacent in the axial direction are partially connected to each other.   The honeycomb body for supporting a catalyst according to claim 2, wherein the offset portion is configured by arranging the fin portions in a staggered manner along the axial direction.   The honeycomb body for supporting a catalyst according to claim 2, wherein the offset portion is configured by arranging the fin portions in an inclined direction inclined with respect to the axial direction.   The honeycomb body for supporting a catalyst according to claim 2, wherein the fin portions arranged in the offset portion all have the same length in the axial direction.   The honeycomb body for supporting a catalyst according to any one of claims 2 to 5, wherein the pair of side sides are formed in a tapered shape that is spaced apart from the top surface. A honeycomb body according to any one of claims 1 to 6,
An outer cylinder accommodating the honeycomb body;
A catalyst carrier comprising:

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