JP6279368B2 - Exhaust gas purification device - Google Patents

Description

  The present invention relates to an exhaust gas purification device, and more particularly to an exhaust gas purification device that can stably collect particulate matter and suppress ash accumulation.

  In recent years, it has been demanded to collect “particulate matter mainly composed of carbon” discharged from internal combustion engines such as automobiles, railways, construction machines, and agricultural machines, particularly diesel engines. Hereinafter, the particulate matter may be referred to as “PM” or “particulate matter”. “Particulate matter containing carbon as a main component” is sometimes referred to as “soot”. It is also required to collect PM discharged from a gasoline engine such as a GDI (Gasoline Direct Injection) engine. On the other hand, recently, one end of a predetermined cell and the other end of the remaining cell are plugged, and the predetermined cell and the remaining cell are alternately arranged. The sealed honeycomb structure is used as a diesel particulate filter (DPF). And the method of collecting PM discharged | emitted from a diesel engine etc. by such DPF is used actively (for example, refer patent document 1).

  According to such a DPF, the exhaust gas flows into the cell from the end face on the inlet side of the exhaust gas, the exhaust gas that has flowed into the cell passes through the partition wall, and the exhaust gas that has passed through the partition wall (in other words, purified gas) The exhaust gas is discharged from the end face on the outlet side. And when exhaust gas passes a partition, PM contained in exhaust gas is collected by a partition, and exhaust gas is purified.

  However, in the conventional “honeycomb structure with plugged portions formed on both end faces”, all of the inflowing exhaust gas passes through the partition walls, and most of the particulate matter in the exhaust gas is collected by the partition walls. Therefore, the pressure loss is likely to increase. In addition, ash (Ash) is generated by impurities (S, Ca, etc.) contained in trace amounts in engine oil and fuel, and the ash accumulates in the DPF cell after a long period of operation, increasing pressure loss. There was a problem to do. In this specification, “pressure loss” may be referred to as “pressure loss”.

  In order to solve such problems, there has been proposed a honeycomb structure (honeycomb filter) in which a plugging portion is formed only on an end surface on the exhaust gas outflow side (see, for example, Patent Documents 2 to 4). .

JP 2003-254034 A JP 2002-537965 A Japanese Patent No. 39442086 JP 2004-251137 A

  However, in the honeycomb filter in which the plugged portions are formed only on the end surface on the exhaust gas outflow side, the PM is collected as PM is collected on the partition wall surface in the cell in which the plugged portions are formed. The efficiency was greatly reduced. Further, ash is accumulated in the cell in which the plugged portions are formed, and the space in the cell is filled with the ash, so that the collection performance is further deteriorated.

  Moreover, the amount of PM discharged from the engine has been reduced due to recent improvements in engine combustion technology. Due to the reduction in the amount of PM discharged from the engine, there are cases where a collection efficiency of 90% or more is not necessarily required. If the carbon component contained in about 60% by mass of PM discharged from the engine (a component not treated with an oxidation catalyst and containing carbon as a main component) can be collected at a collection efficiency of 10 to 70%. It has become possible to adapt to the emission regulations of each country. In general, about 40% by mass of PM discharged from the engine is an organic solvent soluble component (SOF), and the remaining about 60% is mainly a carbon component. And about SOF, it is possible to remove with an oxidation catalyst (DOC).

  The present invention has been made in view of such problems of the prior art. Even when the amount of collected PM is increased, the PM is collected without greatly reducing the PM collection efficiency. Furthermore, an exhaust gas purifying apparatus that can suppress ash accumulation is provided. In addition, the present invention provides an exhaust gas purifying apparatus capable of realizing higher collection performance that could not be realized with a conventional one-side sealed structure.

  According to the present invention, the following exhaust gas purification apparatus is provided.

[1] A honeycomb having a porous partition wall that penetrates from an inflow end surface, which is an end surface on the exhaust gas inflow side, to an outflow end surface, which is an end surface on the exhaust gas outflow side, and defines a plurality of cells serving as fluid flow paths. Provided with a base material, and some of the cells are inlet plugged cells whose ends are substantially plugged by plugged portions on the inflow end face side of the honeycomb base material, and the remaining cells Is a penetrating cell that penetrates substantially from the inflow end face side to the outflow end face side, and the inlet plugged cell and the penetrating cell are disposed adjacent to each other and perpendicular to the extending direction of the cell. In cross section, the honeycomb structure has a hydraulic diameter A2 of the inlet plugged cell larger than the hydraulic diameter A1 of the through-cell, an inlet port for exhaust gas and an outlet port for purified exhaust gas. And the honeycomb structure A cylindrical storage container, wherein the honeycomb structure has the inflow end surface facing the inlet side of the storage container and the outflow end surface of the storage container facing the outlet side of the storage container. And an exhaust gas purification device disposed in the storage container.

[2] The exhaust gas purification apparatus according to [1], wherein a ratio (A1 / A2) of the hydraulic diameter A1 of the through-cell and the hydraulic diameter A2 of the inlet plugged cell is 0.9 or less.

[3] The exhaust gas purification apparatus according to [1] or [2], wherein a hydraulic diameter A1 of the through cell is 0.7 to 2.1 mm.

[4] The exhaust gas purification apparatus according to any one of [1] to [3], wherein a hydraulic diameter A2 of the inlet plugged cell is 0.8 to 3.0 mm.

[5] Honeycomb having a porous partition wall that penetrates from an inflow end surface, which is an end surface on the exhaust gas inflow side, to an outflow end surface, which is an end surface on the exhaust gas outflow side, and defines a plurality of cells serving as fluid flow paths. Provided with a base material, and some of the cells are inlet plugged cells whose ends are substantially plugged by plugged portions on the inflow end face side of the honeycomb base material, and the remaining cells Is a penetrating cell that penetrates substantially from the inflow end face side to the outflow end face side, and the inlet plugged cell and the penetrating cell are disposed adjacent to each other and perpendicular to the extending direction of the cell. In cross-section, there is a honeycomb structure having a cross-sectional area B2 of the inlet plugged cell larger than the cross-sectional area B1 of the through-cell, an inflow port through which exhaust gas flows and an outflow port from which purified exhaust gas flows out. The honeycomb structure A tubular storage container, wherein the honeycomb structure has the inflow end surface facing the inlet side of the storage container and the outflow end surface facing the outlet side of the storage container. An exhaust gas purification device disposed in the storage container.

[6] The exhaust gas purification apparatus according to [5], wherein a ratio (B1 / B2) of a cross-sectional area B1 of the through-cell and a cross-sectional area B2 of the inlet plugged cell is 0.9 or less.

[7] The exhaust gas purification apparatus according to [5] or [6], wherein a cross-sectional area B1 of the through cell is 0.49 to 5.30 mm ² .

[8] The exhaust gas purification apparatus according to any one of [5] to [7], wherein a cross-sectional area B2 of the inlet plugged cell is 0.64 to 9.00 mm ² .

[9] The honeycomb structure is disposed in a state where the inflow end surface of the honeycomb structure faces the inflow port side of the storage container and the outflow end surface of the honeycomb structure faces the outflow port side of the storage container, The housing further includes at least one other honeycomb structure, and the other honeycomb structure is arranged in series with respect to the honeycomb structure in the exhaust gas flow direction. The exhaust gas purification apparatus according to any one of [1] to [8], which is disposed in a container.

[10] At least one other honeycomb structure is disposed upstream of the honeycomb structure in the flow direction of the exhaust gas, and the other honeycomb structure has both ends thereof plugged by plugging portions. The exhaust gas purifying apparatus according to [9], wherein the device has a cell that is not substantially sealed.

[11] A plurality of other honeycomb structures including the honeycomb structure are arranged in the storage container so as to be arranged in series in the flow direction of the exhaust gas, and the other honeycomb structures arranged on the upstream side are arranged. When the number of plugged portions is Pk, the number of plugged portions of the honeycomb structure is Pm, and the number of plugged portions of the other honeycomb structure disposed on the downstream side is Pn, Pk ≦ The exhaust gas purification apparatus according to any one of [1] to [8] , wherein Pm or Pm ≦ Pn.

[12] In the plurality of honeycomb structures, the inflow end surface of the honeycomb structure faces the inlet side of the storage container, and the outflow end surface of the honeycomb structure faces the outlet side of the storage container. The exhaust gas purifying apparatus according to any one of [1] to [11], disposed in the storage container so as to be arranged in series in the exhaust gas flow direction.

[13] First through-cells of the honeycomb structure disposed in the storage container and arranged upstream of the exhaust gas flow direction so that the plurality of honeycomb structures are arranged in series in the exhaust gas flow direction [9] to [12], where Ak is the hydraulic diameter of Ak and Am is the hydraulic diameter of the second through-cell of the honeycomb structure disposed on the downstream side in the exhaust gas flow direction. The exhaust gas purification apparatus according to any one of the above.

[14] The first through-cell of the honeycomb structure, which is arranged in the storage container so that a plurality of the honeycomb structures are arranged in series in the flow direction of the exhaust gas, and arranged on the upstream side in the flow direction of the exhaust gas [9] to [12], where Bk is equal to Bm, where Bk is the cross-sectional area of the second through-cell of the honeycomb structure disposed on the downstream side in the exhaust gas flow direction. The exhaust gas purification apparatus according to any one of the above.

  According to the exhaust gas purification apparatus of the present invention, particulate matter can be collected stably, and accumulation of ash can be suppressed. That is, in the exhaust gas purification apparatus of the present invention, when exhaust gas is introduced from the inlet side of the storage container, the collection efficiency of the particulate matter is greatly reduced even if the amount of the particulate matter collected is increased. The particulate matter can be collected without the ash, and further the accumulation of ash can be suppressed.

  In the honeycomb structure used in the exhaust gas purifying apparatus of the present invention, plugging portions are disposed only at the end portions of some cells (that is, inlet plugged cells) on the inflow end surface. With this structure, when exhaust gas flows into a through-cell in which no plugging portion is disposed, the pressure in the through-cell increases, and the pressure in the inlet plugged cell adjacent to the through-cell increases in the through-cell. Relative to pressure. Therefore, a part of the exhaust gas passes through the partition wall from the through cell and flows into the inlet plugged cell, and the side of the inlet plugged cell where the plugged portion is not disposed (outflow end surface of the honeycomb substrate) The exhaust gas that has permeated through the partition wall is discharged from the end of the side. And since particulate matter contained in exhaust gas accumulates on the partition in a penetration cell because a part of exhaust gas permeate | transmits a partition in this way, particulate matter can be collected. Furthermore, as particulate matter accumulates on the partition walls, the particulate matter deposited on the partition walls makes it difficult for the exhaust gas to flow into the inlet plugged cell side. The flow path becomes narrower, and accordingly, the exhaust gas hardly flows into the through cell. For this reason, particulate matter can be collected by the balance of both, without significantly reducing the collection efficiency.

  In the exhaust gas purifying apparatus of the present invention, the remainder of the exhaust gas that has flowed into the through-cells from the inflow end face side of the honeycomb substrate (the remaining portion of the exhaust gas that has flowed into the through-cells through the partition walls) , It passes through the through-cell and is discharged from the outflow end face side. Since the soot collected by the honeycomb structure burns during operation by forced regeneration or natural regeneration, the cell structure is prevented from being blocked by soot, and the honeycomb structure can be used for a long time. Furthermore, the ash contained in the exhaust gas can be discharged to the outside through the through cell. Since ash can be discharged to the outside of the honeycomb structure through the through-cells, ash is not accumulated in the honeycomb structure, and an increase in pressure loss due to accumulation of ash can be suppressed. Therefore, in the exhaust gas purifying apparatus of the present invention, the honeycomb structure (exhaust gas purifying apparatus) can be continuously used without lowering the particulate matter collection efficiency. Note that the amount of ash discharged to the outside of the honeycomb structure is sufficiently small and can meet the exhaust gas regulations.

  Furthermore, in the honeycomb structure used in the exhaust gas purification apparatus of the present invention, the hydraulic diameter A2 of the inlet plugged cell is larger than the hydraulic diameter A1 of the through-cell in the cross section perpendicular to the cell extending direction. The pressure loss in the cell channel when the gas flows into the inlet plugged cell is low. Therefore, when exhaust gas flows into the through cell, a differential pressure is likely to be generated between the through cell and the inlet plugged cell, and the exhaust gas is more actively transferred from the through cell to the inlet plugged cell. Become. For this reason, PM in exhaust gas can be satisfactorily collected by the partition arranged by separating the penetration cell and the inlet plugged cell. The honeycomb structure used in the exhaust gas purifying apparatus of the present invention has a cross-sectional area B2 of the inlet plugged cell larger than the cross-sectional area B1 of the through-cell in the cross section perpendicular to the cell extending direction. There may be. By using the honeycomb structure configured as described above, the same effect as that in the case of using the honeycomb structure in which the hydraulic diameter A2 of the inlet plugged cell is larger than the hydraulic diameter A1 of the through-cell is obtained. be able to.

  Further, conventionally, in a DPF in which both end faces are alternately plugged, the size of the cell on the gas inflow side is made larger than the size of the cell on the gas outflow side, so that unburned ash can be removed in the cell on the inflow side. It has been considered to accumulate more. Here, the “cell on the gas inflow side” refers to a cell in which a plugging portion is disposed on an end surface from which exhaust gas flows out. The “cell on the gas outflow side” refers to a cell in which a plugging portion is disposed on an end surface into which exhaust gas flows.

  However, in the present invention, the idea is reversed, and the size of the cell in which the plugging portion is disposed on the inlet side is made larger than that of the cell into which the gas flows (through cell). As a result, it is possible to improve the collection performance, which is a disadvantage of the one-end-side sealed structure, in particular, to improve the collection performance per carrier, which was theoretically less than 50%, to 50% or more. Is also possible. Here, the “carrier” is a honeycomb structure having a plugged portion.

It is a schematic diagram which shows 1st embodiment of the exhaust gas purification apparatus of this invention, and shows a cross section parallel to the direction through which exhaust gas flows. FIG. 2 is a perspective view schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention as seen from the inflow end face side. FIG. 3 is a perspective view schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention as seen from the outflow end face side. FIG. 3 is a plan view on the inflow end face side schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention. FIG. 3 is a plan view on the outflow end face side schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention. It is sectional drawing which shows typically the X-X 'cross section of FIG. 2A. 1 is a schematic diagram showing a honeycomb structure constituting a first embodiment of an exhaust gas purification apparatus of the present invention and showing a cross section parallel to a cell extending direction. FIG. 1 is a schematic diagram showing a honeycomb structure constituting a first embodiment of an exhaust gas purification apparatus of the present invention and showing a cross section parallel to a cell extending direction. FIG. It is a schematic diagram which shows 3rd embodiment of the waste gas purification apparatus of this invention, and shows a cross section parallel to the flow direction of waste gas. It is a schematic diagram which shows 4th embodiment of the exhaust gas purification apparatus of this invention, and shows a cross section parallel to the flow direction of exhaust gas. 3 is a schematic diagram showing a cell shape of a honeycomb structure constituting the exhaust gas purifying apparatus of Example 1. FIG. 3 is a schematic diagram showing a cell shape of a honeycomb structure constituting the exhaust gas purifying apparatus of Comparative Example 1. FIG. 4 is a schematic diagram showing a cell shape of a honeycomb structure constituting the exhaust gas purifying apparatus of Example 2. FIG. 6 is a schematic diagram showing a cell shape of a honeycomb structure constituting the exhaust gas purifying apparatus of Example 3. FIG. 6 is a schematic diagram showing a cell shape of a honeycomb structure constituting the exhaust gas purifying apparatus of Example 4. FIG. 6 is a schematic diagram showing a cell shape of a honeycomb structure constituting the exhaust gas purifying apparatus of Comparative Example 2. FIG. It is a graph which shows the measurement result of the collection efficiency about the exhaust gas purification apparatus of Examples 1, 2 and Comparative Examples 1, 2. It is a graph which shows the measurement result of the collection efficiency about the exhaust gas purification apparatus of Examples 3-6 and Comparative Examples 1 and 2. It is a graph which shows the measurement result of the collection efficiency about the exhaust gas purification apparatuses of Examples 7 to 9 and Comparative Examples 1 and 2.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. Accordingly, it is understood that modifications, improvements, and the like to the following embodiments are also included in the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

(1) Exhaust gas purification device:
As shown in FIG. 1, the first embodiment of the exhaust gas purification apparatus of the present invention includes a honeycomb structure 100 and a cylindrical storage container 21 in which the honeycomb structure 100 is stored. As shown in FIG. 1 and FIGS. 2A to 2E, the honeycomb structure 100 includes a honeycomb substrate 4 having porous partition walls 1. The porous partition wall 1 defines a plurality of cells 2 that penetrate from an inflow end surface 11 that is an end surface on the exhaust gas inflow side to an outflow end surface 12 that is an end surface on the exhaust gas outflow side to serve as a fluid flow path. It is. In the honeycomb structure 100, some of the cells 2 are inlet plugged cells 2 b whose end portions are substantially closed by the plugged portions 5 on the inflow end face 11 side of the honeycomb base material 4. The cell 2 is a penetrating cell 2a that penetrates substantially from the inflow end face 11 side to the outflow end face 12 side. In the honeycomb structure 100, the inlet plugged cells 2b and the through cells 2a are arranged adjacent to each other. Furthermore, in the honeycomb structure 100, the hydraulic diameter A2 of the inlet plugged cell 2b is larger than the hydraulic diameter A1 of the through-cell 2a in a cross section perpendicular to the cell 2 extending direction (for example, the cross section shown in FIG. 2E). It ’s big.

  Here, FIG. 1 shows a first embodiment of the exhaust gas purifying apparatus of the present invention, and is a schematic diagram showing a cross section parallel to the flowing direction of the exhaust gas. FIG. 2A is a perspective view schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention as seen from the inflow end face side. FIG. 2B is a perspective view schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention as seen from the outflow end face side. FIG. 2C is a plan view of the inflow end face side schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention. FIG. 2D is a plan view on the outflow end face side schematically showing the honeycomb structure constituting the first embodiment of the exhaust gas purifying apparatus of the present invention. FIG. 2E is a cross-sectional view schematically showing the X-X ′ cross section of FIG. 2A.

  The storage container 21 has an inlet 22 through which the exhaust gas G flows in and an outlet 23 through which the purified exhaust gas G flows out, and is formed in a cylindrical shape so that the honeycomb structure 100 can be stored. This storage container 21 becomes a housing in the exhaust gas purification apparatus 200 of the present embodiment. In the exhaust gas purification apparatus 200 of the present embodiment, the honeycomb structure 100 is stored so that the inflow end surface 11 faces the inlet 22 side of the storage container 21 and the outflow end surface 12 faces the outlet 23 side of the storage container 21. Arranged in the container 21.

  Since the exhaust gas purification apparatus 200 of the present embodiment is configured as described above, the particulate matter is captured without greatly reducing the collection efficiency of the particulate matter even if the amount of the particulate matter collected is increased. In addition, the accumulation of ash can be suppressed. Hereinafter, the exhaust gas purification device will be described for each component.

(1-1) Honeycomb structure:
A honeycomb structure 100 constituting the first embodiment of the exhaust gas purifying apparatus of the present invention will be described. As shown in FIGS. 2A to 2E and FIG. 3A, a honeycomb structure 100 includes a honeycomb base material 4 having porous partition walls 1 for partitioning a plurality of cells, and an inflow end face 11 side of some cells 2. A plugging portion 5 that substantially closes the end portion is provided. Therefore, some of the cells 2 become inlet plugged cells 2b whose ends are substantially blocked by the plugged portions 5 on the inflow end face 11 side of the honeycomb base material 4, and the remaining cells 2 are The penetration cell 2a substantially penetrates from the inflow end face 11 side to the outflow end face 12 side. In the honeycomb structure 100, the inlet plugged cells 2b and the through cells 2a are arranged adjacent to each other. Here, “the end portion of the cell is“ substantially blocked by the plugged portion ”” means that the end portion of the cell is blocked by the plugged portion so that the exhaust gas hardly passes through the cell. It means a state. There may be a slight amount of gas flow passing through the plug due to the slight gap formed during the plug formation and the plugged portion 5 being a porous body. Further, “the cell penetrates“ substantially ”” means a state in which the exhaust gas can pass through the cell. This includes a case where the exhaust gas can pass through the cell even if the plugged portion or the like is disposed in the cell due to a state where a hole is opened in the plugged portion or the like. Here, FIG. 3A is a schematic view showing the honeycomb structure 100 constituting the first embodiment of the exhaust gas purifying apparatus of the present invention and showing a cross section parallel to the cell extending direction. In the honeycomb structure 100, the “cell extending direction” is the central axis direction of the cylindrical honeycomb structure 100.

  According to the honeycomb structure 100 configured as described above, when the exhaust gas G is caused to flow from the inflow end face 11 of the honeycomb substrate 4, the particulate matter contained in the exhaust gas G is partitioned and formed in the through cells 2 a. It can be collected by the partition wall 1. That is, in the honeycomb structure 100, the plugged portions 5 are disposed only at the end portions of the inlet plugged cells 2 b on the inflow end surface 11 of the honeycomb substrate 4. With this structure, when the exhaust gas G flows into a cell in which the plugging portion 5 is not disposed (that is, the through cell 2a), the pressure in the through cell 2a rises, and the inlet plugging adjacent to the through cell The pressure in the cell 2b becomes relatively lower than the pressure in the through cell 2a. Therefore, a part of the exhaust gas G passes through the porous partition wall 1 from the through cell 2a and flows into the inlet plugged cell 2b, and the plugged portion 5 of the inlet plugged cell 2b is provided. Exhaust gas G that has permeated through the partition walls 1 is discharged from the end portion on the non-existing side (the outflow end face 12 side of the honeycomb substrate 4). By adjoining the through cell and the inlet plugged cell, the exhaust gas passes through the porous partition located between the through cell and the inlet plugged cell in this way, Can be moved to a sealed cell. And, as shown in FIG. 3B, the particulate matter 13 contained in the exhaust gas G is deposited on the partition walls 1 in the through-cells 2a when a part of the exhaust gas G permeates the partition walls 1 in this way. Particulate matter can be collected. FIG. 3B is a schematic view showing a honeycomb structure 100 constituting the first embodiment of the exhaust gas purifying apparatus of the present invention and showing a cross section parallel to the cell extending direction.

  Further, as shown in FIG. 3A, the remaining portion of the exhaust gas G that has flowed into the through cell 2a from the inflow end surface 11 side of the honeycomb substrate 4 passes through the through cell 2a and is discharged from the outflow end surface 12 side. Here, the “remaining part of the exhaust gas G” refers to a remaining part of “a part of the exhaust gas G that permeates the partition wall 1” in the exhaust gas G that has flowed into the through-cell 2a. As described above, since the remaining part of the exhaust gas G is discharged from the outflow end face 12 side, when the accumulated soot is regenerated and burned, the ash contained in the exhaust gas G can be discharged to the outside through the penetration cell 2a. it can. Therefore, in the exhaust gas purifying apparatus of the present embodiment, ash can be prevented from accumulating (depositing) in the honeycomb structure, and an increase in pressure loss due to ash accumulation (deposition) can also be suppressed. . As described above, the exhaust gas purifying apparatus of the present embodiment can continue to use the honeycomb structure without reducing the collection efficiency of the particulate matter.

  Further, as shown in FIGS. 2A to 2E and 3A, the honeycomb structure 100 constituting the exhaust gas purifying apparatus of the present embodiment has a hydraulic diameter A1 of the penetrating cell 2a in a cross section perpendicular to the extending direction of the cell 2. However, the hydraulic diameter A2 of the inlet plugged cell 2b is large. Therefore, when the exhaust gas G flows into the through cell 2a, a differential pressure is likely to be generated between the through cell 2a and the inlet plugged cell 2b, and the movement of the exhaust gas G from the through cell 2a to the inlet plugged cell 2b is more likely. It will be done actively. That is, compared with the case where the hydraulic diameter of the penetration cell 2a and the inlet plugged cell 2b is the same value, the pressure in the penetration cell 2a becomes relatively high, or the pressure in the inlet plugged cell 2b is higher. Relatively low. For this reason, the particulate matter 13 (see FIG. 3B) in the exhaust gas G can be favorably collected by the partition wall 1 that is disposed with the through cell 2a and the inlet plugged cell 2b separated.

  Further, when the honeycomb structure 100 is used, it is necessary to allow exhaust gas to flow from the inflow end face 11 side. Assuming that after exhaust gas is introduced from the inflow end face 11 side, the flow of exhaust gas is switched, the exhaust gas is introduced from the outflow end face 12 side, and then the exhaust gas is introduced again from the inflow end face 11 side, May cause such a situation. That is, first, when exhaust gas is introduced from the outflow end face 12 side, particulate matter adheres to the partition walls 1 in the inlet plugged cells 2b. Thereafter, when the exhaust gas is again introduced from the inflow end face 11 side, the particulate matter adhering to the partition wall 1 in the inlet plugged cell 2b passes through the partition wall of the exhaust gas (that is, from the through cell 2a to the inlet plugged cell 2b). Passage), and the exhaust gas purification efficiency is reduced. For this reason, the exhaust gas must be allowed to flow from the inflow end face 11 side, and it is necessary to prevent the unpurified exhaust gas from flowing into the inlet plugged cell 2b.

(1-1a) Honeycomb substrate:
As shown in FIG. 2A to FIG. 2E and FIG. 3A, the honeycomb substrate 4 includes a porous partition wall 1 that defines a plurality of cells 2 that serve as fluid flow paths, and an outer peripheral wall 3 disposed on the outer periphery. It is what you have. Note that the honeycomb substrate 4 constituting the honeycomb structure 100 does not necessarily have the outer peripheral wall 3. Further, since the partition walls 1 constituting the honeycomb substrate 4 are porous, it can be said that the honeycomb substrate 4 is a porous substrate.

  The honeycomb substrate 4 has a cross section perpendicular to the cell 2 extending direction so that the hydraulic diameter A2 of the cell 2 serving as the inlet plugged cell 2b is larger than the hydraulic diameter A1 of the cell 2 serving as the penetrating cell 2a. It is configured. Here, the “hydraulic diameter” is the diameter of the largest circle inscribed in the cell. The hydraulic diameter of each cell 2 is a value obtained by measuring a cross section of the cell 2 in the axial direction by microscopic observation.

  The ratio (A1 / A2) of the hydraulic diameter A1 of the penetrating cell and the hydraulic diameter A2 of the inlet plugged cell is preferably 0.9 or less, more preferably 0.4 to 0.9, Particularly preferred is 0.6 to 0.9. By comprising in this way, when exhaust gas flows in into a penetration cell from the inflow end surface side, a bigger difference can be produced in the pressure in a penetration cell, and the pressure in an inlet plugging cell. Therefore, the amount of exhaust gas moving from the through cell to the inlet plugged cell is increased, and the collection efficiency for collecting the particulate matter is improved. In particular, when 0.4 to 0.9, the balance between the collection performance and the pressure loss is good, and when 0.6 to 0.8, the soot blockage risk of the cell can be further suppressed.

  It is preferable that hydraulic diameter A1 of a penetration cell is 0.7-2.1 mm, and it is still more preferable that it is 0.9-1.5 mm. If the hydraulic diameter A1 of the penetrating cell is less than 0.7 mm, there is a risk that soot is clogged at the end face, which is not preferable. When the hydraulic diameter A1 of the penetrating cell exceeds 2.1 mm, the collection performance deteriorates, which is not preferable. Moreover, it is preferable that hydraulic diameter A1 of a penetration cell is 0.9-1.5 mm, in order to ensure the pressure loss surface at the time of soot deposition, and a catalyst carrying | support area.

The hydraulic diameter A2 of the inlet plugged cell is preferably 0.8 to 3.0 mm, and more preferably 1.1 to 1.7 mm. If the hydraulic diameter A2 of the inlet plugged cell is less than 0.8 mm , the pressure loss increases, which is not preferable. When the hydraulic diameter A2 of the inlet plugged cell exceeds 3.0 mm, the partition wall area per carrier volume decreases, which is not preferable in terms of soot deposition pressure loss and soot regeneration combustion. In the present embodiment, the term “support” means a honeycomb substrate or a honeycomb structure. “Soot regeneration” and “soot regeneration combustion” mean that soot accumulated on the partition walls of the honeycomb structure is burned to regenerate the filter function of the honeycomb structure.

  The shape of the cells of the honeycomb substrate is not particularly limited, but is preferably a triangle, a quadrangle, a pentagon, a hexagon, an octagon or other polygon, a circle, or an ellipse in a cross section orthogonal to the cell extending direction. Other irregular shapes may also be used. A combination of a square and an octagon is also a preferred embodiment. In the honeycomb structure constituting the exhaust gas purifying apparatus of the present embodiment, the cell 2 of the honeycomb substrate 4 is formed so that the hydraulic diameter A2 of the inlet plugged cell is larger than the hydraulic diameter A1 of the through-cell. Has been. For example, the shape of the penetrating cell and the shape of the inlet plugged cell may be similar or different. Further, by making the shape of at least one of the through cell and the inlet plugged cell a horizontally long or vertically long shape, a difference is provided between the hydraulic diameter A1 of the through cell and the hydraulic diameter A2 of the inlet plugged cell. You can also. For example, when the shape of the inlet plugged cell is a square, the hydraulic diameter A1 of the penetrating cell is set to the inlet plugging by making the shape of the penetrating cell a rectangle that is crushed in one direction. It can be made smaller than the hydraulic diameter A2 of the stop cell.

  The porosity of the partition walls is preferably 50 to 80%, more preferably 55 to 67%. If it is less than 50%, the collection performance may be remarkably deteriorated. If it is more than 80%, the strength of the honeycomb base material is lowered, so that it becomes difficult to perform canning (being damaged when stored in a storage container). Sometimes. Further, when the porosity is 55 to 67%, the collection efficiency (100 × [mass of collected particulate matter] / [mass of inflowing particulate matter]) per honeycomb structure is stable. And can be made 20% or more. Further, when the porosity is 55 to 67%, the strength of the honeycomb structure is improved and canning is facilitated. The porosity of the partition wall is a value measured with a mercury porosimeter.

  The thickness of the partition wall is preferably 0.10 to 0.40 mm, and more preferably 0.12 to 0.38 mm. If it is thinner than 0.10 mm, the strength of the honeycomb substrate may be lowered. If it is thicker than 0.40 mm, the collection performance may be reduced and the pressure loss may be increased. In addition, when processing exhaust gas discharged from a diesel engine (when using an exhaust gas purification device for a diesel engine), the amount of PM in the exhaust gas discharged from the diesel engine is relatively large. There is a tendency to reduce (cell density). Therefore, it is preferable that the thickness of the partition wall 1 is 0.20 to 0.38 mm in order to improve the balance between strength and collection performance. In addition, when processing exhaust gas discharged from a gasoline engine (when using an exhaust gas purification device for a gasoline engine), the amount of PM in the exhaust gas discharged from the gasoline engine is relatively small. There is a tendency to increase (increase the cell density). Therefore, the thickness of the partition wall is preferably 0.12 to 0.20 mm in order to improve the balance between strength and collection performance. The thickness of the partition wall is a value measured by a method of observing a cross section in the axial direction of the honeycomb substrate with a microscope.

  When the honeycomb substrate has a partition wall porosity of 50 to 80% and a partition wall thickness of 0.10 to 0.40 mm, more effectively suppressing an increase in pressure loss, Particulate matter in exhaust gas can be collected. Further, by adopting the porosity and partition wall thickness as described above, the strength of the honeycomb base material is not lowered. In particular, high collection performance can be exhibited by a combination of a porosity of 60% or more and a partition wall thickness of 0.3 mm or less.

The cell density of the honeycomb substrate (the number of cells per unit area in a cross section perpendicular to the cell extending direction of the honeycomb substrate) is preferably 15 to 150 cells / cm ² . If it is less than 15 cells / cm ² , the collection performance may be lowered. When it is larger than 150 cells / cm ² , PM accumulates in the vicinity of the inflow end face of the honeycomb substrate, and the cells are blocked by PM, so that the pressure loss may increase. Moreover, when processing the exhaust gas discharged | emitted from a diesel engine (when using an exhaust gas purification apparatus for diesel engines), it is still more preferable that it is 20-70 cell / cm < ² >. When it is less than 20 cells / cm ² , the collection performance may be lowered. If it is greater than 70 cells / cm ² , the pressure loss may increase. Moreover, when processing the exhaust gas discharged | emitted from a gasoline engine (when using an exhaust gas purification apparatus for gasoline engines), it is still more preferable that it is 30-150 cells / cm < ² >. Since the exhaust gas discharged from a gasoline engine has a small amount of PM, the risk of clogging the cells is low, so the cell density can be increased, and the collection performance can be increased by increasing the cell density. it can. In addition, since the cell is difficult to block, continuous reproduction is also easy. If it is less than 30 cells / cm ² , the collection performance may be lowered, and if it is more than 150 cells / cm ² , the pressure loss during PM collection may be increased.

  The average pore diameter of the partition walls is preferably 80 μm or less, more preferably 0.1 to 80 μm, still more preferably 1 to 80 μm, and particularly preferably 5 to 25 μm. If it is larger than 80 μm, the honeycomb base material becomes brittle and easily lost, and particulate matter may enter the partition walls, resulting in depth filtration. Such a partition wall having a large average pore diameter is not preferable because the particulate matter collecting performance tends to be lowered with PM collection. Moreover, it is not preferable that the average pore diameter of the partition walls is smaller than 0.1 μm because the pressure loss increases even when the particulate matter is little deposited. Furthermore, if the average pore diameter of the partition walls is smaller than 5 μm, the wall permeation resistance (resistance when exhaust gas permeates through the partition walls) when an oxidation catalyst is supported may increase. Moreover, when the average pore diameter of a partition is larger than 25 micrometers, ash (Ash) accumulates inside a partition and possibility that a collection performance will deteriorate after long-term use may become high. The average pore diameter of the partition wall is a value measured with a mercury porosimeter.

  Although the thickness of the outer peripheral wall 3 of the honeycomb base material 4 is not specifically limited, 0.5-6 mm is preferable. If it is thinner than 0.5 mm, cells near the outer periphery are likely to be chipped, and the strength may be reduced. If it is thicker than 6 mm, the pressure loss may increase.

  The shape of the honeycomb substrate (in other words, the shape of the honeycomb structure) is not particularly limited, but a cylindrical shape, an elliptical columnar shape on the bottom, a polygonal columnar shape such as a square, pentagon, hexagon, etc. on the bottom Is preferred. The honeycomb structure preferably has a column shape with the cell extending direction as the central axis direction. Further, the size of the honeycomb substrate (in other words, honeycomb structure) is not particularly limited, but the length in the cell extending direction is preferably 20 to 200 mm. Since the length of the honeycomb substrate is in such a range, the honeycomb structure can treat the exhaust gas with excellent collection performance without increasing the pressure loss. When the length is shorter than 20 mm, the collection performance may be deteriorated, and the effect that the size of the sealing cell is made larger than the size of the penetration cell may not be obtained. On the other hand, when the length is longer than 200 mm, the improvement in the collection performance cannot be expected so much, but the pressure loss may increase. Considering the balance between the collection performance and the pressure loss, the length of the honeycomb substrate is more preferably 60 to 120 mm, and an effect of making the size of the plugged cells larger than the size of the through cells is easily obtained. The configuration of the honeycomb base material described so far is effective particularly when a plurality of honeycomb structures are arranged in series in the storage container. For example, when the outer shape of the honeycomb substrate (in other words, the honeycomb structure) is a columnar shape, the bottom surface (end surface) preferably has a diameter of 80 to 400 mm. The diameter of the bottom surface of the honeycomb base material is appropriately selected within the above range according to the engine displacement and output.

  The partition walls and the outer peripheral wall of the honeycomb base material are preferably composed mainly of ceramic. Specific examples of the material for the partition wall and the outer peripheral wall include silicon carbide, silicon-silicon carbide composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite composite material, lithium aluminum silicate, and aluminum titanate. It is preferably at least one selected from the group consisting of Among these, silicon carbide having excellent thermal conductivity and cordierite having a small thermal expansion coefficient and excellent thermal shock resistance are preferable. In a normal DPF, it is necessary to increase the PM deposition amount and lengthen the regeneration interval. Therefore, a material having a large heat capacity such as silicon carbide is preferable. However, in the present invention, the heat capacity that facilitates continuous regeneration is relatively small. Cordierite is particularly preferred. The material of the partition wall and the outer peripheral wall is preferably the same, but may be different. In addition, the phrase “mainly composed of ceramic” means that 90% by mass or more of ceramic is contained.

(1-1b) Plugging portion:
As shown in FIGS. 1, 2A, and 2C, in the honeycomb structure 100, the plugging portions 5 are arranged so as to close the end portions of some cells 2 on the inflow end surface 11 side of the honeycomb base material 4. The end portions of all the cells 2 are open on the outflow end face 12 side of the honeycomb substrate 4. A part of cells (inlet plugged cells 2b) in which the plugged portions 5 are arranged and a remaining cell (penetrating cells 2a) in which no plugged portions are arranged are arranged adjacent to each other. ing. Further, the inlet plugged cells 2b and the penetrating cells 2a are alternately arranged and arranged on the inflow end face 11 of the honeycomb substrate 4 at the opening of the penetrating cell 2a and the end of the inlet plugged cell 2b. It is preferable that a checkered pattern is formed by the plugged portion.

  The depth of the plugged portion 5 is preferably 1 to 10 mm, and more preferably 1 to 5 mm. If it is shallower than 1 mm, the strength of the plugged portion 5 may be lowered. If it is deeper than 10 mm, the area of the partition wall 1 for collecting the particulate matter may be small. Here, the depth of the plugged portion 5 means the length of the plugged portion 5 in the cell 2 extending direction.

  The material of the plugging portion 5 is preferably the same as the material of the partition walls 1 of the honeycomb substrate 4.

  The value obtained by subtracting the depth of the plugging portion from the length in the cell extending direction of the honeycomb structure is preferably 25 mm or more, more preferably 25 to 500 mm, and more preferably 50 to 200 mm. Particularly preferred. If it is shorter than 25 mm, the area of the partition wall functioning as a filter may be small. Moreover, when it is longer than 500 mm, the pressure loss is high, and it is necessary to reduce the cell density. However, when the cell density is decreased, the collection efficiency may be deteriorated. Furthermore, if the length is 25 to 50 mm, the effect of improving the collection performance by increasing the length is large, and if it is 200 mm or more, it is difficult to obtain the effect, which is disadvantageous in terms of downsizing the apparatus.

(1-1c) Catalyst:
In the exhaust gas purifying apparatus of the present embodiment, it is preferable that “the honeycomb structure is one in which an oxidation catalyst is supported at least partially”. More specifically, it is preferable that the catalyst is supported on the partition walls of the honeycomb substrate constituting the honeycomb structure. The supported amount of the catalyst per unit volume is preferably 0.1 to 150 g / liter, and more preferably 10 to 80 g / liter. “G / liter” indicates the number of grams (g) of catalyst per liter of honeycomb structure. If the amount is less than 0.1 g / liter, the catalytic effect may be difficult to be exhibited. When the amount is more than 150 g / liter, the pores of the partition walls are blocked, resulting in an increase in pressure loss and a significant reduction in collection efficiency. In the case of an oxidation catalyst that forms a washcoat layer, the supported amount of catalyst per unit volume is preferably 10 to 150 g / liter. If the amount of catalyst supported is less than 10 g / liter, it may be difficult to form a washcoat layer.

  Examples of the oxidation catalyst include those containing noble metals, and specifically, those containing at least one selected from the group consisting of Pt, Rh and Pd are preferable. The total amount of the noble metal is preferably 0.1 to 5 g / liter per unit volume of the honeycomb structure.

In the honeycomb structure constituting the exhaust gas purification apparatus of the present embodiment, since the plugging portion is not disposed in the through cell, a part of the inflowed exhaust gas is discharged from the outflow end face side to the outside without being purified. Will be. The particulate matter collection efficiency of one honeycomb structure is preferably 15 to 70%. If it is less than 15%, it is necessary to combine a plurality, and the exhaust gas purification device becomes large, so that the mountability deteriorates. If it is 70% or more, there is an increased concern about blockage of the through-cell, which is not preferable. Here, the “collection efficiency” mentioned above refers to a ratio determined by the following formula (1). Usually, when the size of the penetrating cell and the plugged cell are the same, the collection efficiency of 50% or more cannot be obtained with one carrier, but according to the present invention, the cell size is adjusted. 50% or more of the collection efficiency can be obtained. If it is desired to further improve the collection efficiency of the particulate matter, a plurality of honeycomb structures may be used in series. Thereby, high collection efficiency can be obtained.
Collection efficiency = (W1-W2) / W1 × 100 (1)
(In the above formula (1), W1 indicates the mass of the particulate matter in the exhaust gas flowing into the honeycomb structure, and W2 indicates the mass of the particulate matter in the exhaust gas that flows out of the honeycomb structure.)

(1-2) Storage container:
In the exhaust gas purification apparatus 200 of the present embodiment, the storage container 21 has an inflow port 22 through which exhaust gas flows and an outflow port 23 through which purified exhaust gas flows out, and a cylindrical container in which the honeycomb structure 100 is stored. It is. The storage container 21 is not particularly limited, and a container that is normally used for storing a honeycomb filter for purifying automobile exhaust gas or the like can be used. Examples of the material of the storage container 21 include metals such as stainless steel. The size of the storage container 21 is preferably a size that can be press-fitted with the cushion material 31 wound around the honeycomb structure 100. The storage container 21 is a portion in which both ends of the cylindrical shape are tapered and the diameters of the inlet 22 and the outlet 23 in the “cross section perpendicular to the direction in which the exhaust gas flows” are stored in the central honeycomb structure. It is preferably smaller than the diameter in the “cross section perpendicular to the direction in which the exhaust gas flows”. In addition, the diameter of the inlet 22 is not particularly limited, but it is preferable that the inlet 22 can be connected to the exhaust port of the engine and the pressure loss when the exhaust gas passes is suppressed within a predetermined value. It is preferable that the diameter of the outlet 23 is approximately the same as the diameter of the inlet 22.

(1-3) First embodiment of exhaust gas purification device:
As shown in FIG. 1, the first embodiment of the exhaust gas purifying apparatus of the present invention includes the honeycomb structure 100 and the storage container 21. The exhaust gas purifying apparatus 200 includes the storage container 21 such that the honeycomb structure 100 has the inflow end surface 11 facing the inlet 22 side of the storage container 21 and the outflow end surface 12 faces the outlet 23 side of the storage container 21. It is arranged inside.

  The honeycomb structure 100 is preferably press-fitted into the storage container 21 with the cushion material 31 wound around the outer periphery. When stored in such a state, the honeycomb structure 100 can be prevented from moving in the storage container 21 and can be stabilized in the storage container 21. This prevents the honeycomb structure 100 from being damaged. Although it does not specifically limit as the cushioning material 31, A heat resistant inorganic insulation mat etc. can be mentioned.

  The honeycomb structure 100 is preferably stored in the storage container 21 with both end surfaces fixed by the fasteners 32. The fastener 32 may be a ring shape in which a central portion of a flat plate (a disk or the like) is removed, or may be a plate shape that holds a part of the outer edge of the end face of the honeycomb structure 100. . The material of the fastener 32 may be a ceramic or a metal such as stainless steel or steel.

(1-4) Second embodiment of exhaust gas purification device:
The second embodiment of the exhaust gas purifying apparatus of the present invention uses a honeycomb structure in which the cross-sectional area B2 of the inlet plugged cell is larger than the cross-sectional area B1 of the through cell. That is, as shown in FIG. 2E, the honeycomb structure 100 may have a cross-sectional area B2 of the inlet plugged cell 2b larger than a cross-sectional area B1 of the through-cell 2a. By using the honeycomb structure configured as described above, the same effect as that in the case of using the honeycomb structure in which the hydraulic diameter A2 of the inlet plugged cell is larger than the hydraulic diameter A1 of the through-cell is obtained. be able to. Of course, in the honeycomb structure 100, the hydraulic diameter A2 of the inlet plugged cell is larger than the hydraulic diameter A1 of the through cell 2a, and the inlet plugged cell 2b is larger than the cross-sectional area B1 of the through cell 2a. The cross-sectional area B2 may be large. For example, the honeycomb structure 100 illustrated in FIG. 2E is a honeycomb structure 100 that satisfies both the configuration of the first embodiment of the exhaust gas purification device and the configuration of the second embodiment of the exhaust gas purification device.

  The ratio (B1 / B2) of the cross-sectional area B1 of the through-cell and the cross-sectional area B2 of the inlet plugged cell is preferably 0.9 or less, more preferably 0.2 to 0.9, It is especially preferable that it is 0.4-0.8. By comprising in this way, when exhaust gas flows in into a penetration cell from the inflow end surface side, a bigger difference can be produced in the pressure in a penetration cell, and the pressure in an inlet plugging cell. Therefore, the amount of exhaust gas moving from the through cell to the inlet plugged cell is increased, and the collection efficiency for collecting the particulate matter is improved. By setting the ratio (B1 / B2) to 0.2 to 0.9, the balance between the collection performance and the pressure loss is good, and by setting the ratio (B1 / B2) to 0.4 to 0.8, the cell The risk of soot blockage can be reduced.

Sectional area B1 of the through cells is preferably 0.49～5.30Mm ^2, and further preferably from 0.80~2.25mm ^2. If the cross-sectional area B1 of the penetrating cell is less than 0.49 mm ² , there is a risk that the soot is clogged at the end face, which is not preferable. When the cross-sectional area B1 of the penetration cell exceeds 5.30 mm ² , the collection performance is deteriorated, which is not preferable. Moreover, it is preferable that the cross-sectional area B1 of the penetration cell is 0.80 to 2.25 mm ² in terms of ensuring the pressure loss surface, the soot regeneration combustion surface, and the catalyst supporting area during soot deposition.

Sectional area B2 of the inlet plugged cells, it is preferably 0.64～9.00Mm ^2, and further preferably from 1.20~2.78mm ^2. If the cross-sectional area B2 of the inlet plugged cell is less than 0.64 mm ² , the pressure loss is undesirably high. If the cross-sectional area B2 of the inlet plugged cell exceeds 9.00 mm ² , the area of the partition wall per carrier volume decreases, and there is a risk of increased pressure loss during soot deposition, which is not preferable. Moreover, it is preferable that the cross-sectional area B2 of the inlet plugged cell is 1.20 to 2.78 mm ² in terms of ensuring a pressure loss surface during soot deposition, a soot regeneration combustion surface, and a catalyst supporting area.

  The exhaust gas purification apparatus of the second embodiment is the same as that of the first embodiment except that the above-described “honeycomb structure in which the cross-sectional area B2 of the inlet plugged cell is larger than the cross-sectional area B1 of the through-cell” is used. It is preferable that it is comprised similarly to this exhaust gas purification apparatus.

(1-5) Third and fourth embodiments of exhaust gas purification device:
The third and fourth embodiments of the exhaust gas purification apparatus of the present invention are exhaust gas purification apparatuses further provided with at least one other honeycomb structure in addition to the honeycomb structure described so far. The exhaust gas purification apparatus 210 shown in FIG. 4A is an exhaust gas purification apparatus 210 that further includes at least one other honeycomb structure 110 in addition to the honeycomb structure 100 described so far. The exhaust gas purification device 220 shown in FIG. 4B is also an exhaust gas purification device 220 further provided with at least one other honeycomb structure 120 in addition to the honeycomb structure 100 described so far. There is no restriction | limiting in particular about the structure of the other honeycomb structures 110 and 120, According to a preferable aspect, it can change suitably. Hereinafter, various preferred embodiments including configurations of other honeycomb structures 110 and 120 will be described.

  In the exhaust gas purification apparatuses 210 and 220 of the present embodiment, the inflow end surface 11 of the honeycomb structure 100 faces the inlet 22 side of the storage container 21 and the outflow end surface 12 of the honeycomb structure 100 is on the outlet 23 side of the storage container 21. It is arranged with facing. The exhaust gas purification apparatus 210 of the third embodiment further includes at least one other honeycomb structure 110 with respect to the honeycomb structure 100. In the exhaust gas purification apparatus 210, another honeycomb structure 110 is arranged in the storage container 21 so as to be arranged in series in the exhaust gas flow direction with respect to the honeycomb structure 100. Here, “arranged in the storage container so as to be arranged in series in the flow direction of the exhaust gas” means arranged as follows. First, the exhaust gas flowing in from the inlet of the storage container flows into one honeycomb structure from the inflow end surface, passes through the one honeycomb structure, and is discharged from the outflow end surface. The exhaust gas (or purified gas) discharged from the one honeycomb structure flows into the other honeycomb structure from the inflow end surface, passes through the other honeycomb structure, and is discharged from the outflow end surface. Then, the exhaust gas (or purified gas) discharged from the other honeycomb structure flows out from the outlet of the storage container. Two honeycomb structures are arranged in the storage container so as to ensure the flow of exhaust gas as described above. Also in the exhaust gas purifying apparatus 220 of the fourth embodiment, the other honeycomb structure 120 is arranged in the storage container 21 so as to be arranged in series in the exhaust gas flow direction with respect to the honeycomb structure 100.

  Here, in 3rd and 4th embodiment, the honeycomb structure 100 is comprised similarly to the honeycomb structure which comprises 1st embodiment. That is, the honeycomb structure 100 satisfies the following configuration. The honeycomb structure 100 includes a honeycomb substrate 4 having porous partition walls 1. The honeycomb substrate 4 is porous to partition and form a plurality of cells 2 that penetrate from an inflow end surface 11 that is an end surface on the exhaust gas inflow side to an outflow end surface 12 that is an end surface on the exhaust gas outflow side to serve as fluid flow paths. The partition wall 1 is provided. In the honeycomb structure 100, some of the cells 2 are inlet plugged cells 2 b whose end portions are substantially closed by the plugged portions 5 on the inflow end face 11 side of the honeycomb base material 4. The cell 2 is a penetrating cell 2a that penetrates substantially from the inflow end face 11 side to the outflow end face 12 side. In the honeycomb structure 100, the inlet plugged cells 2b and the through cells 2a are arranged adjacent to each other. Furthermore, in the honeycomb structure 100, the hydraulic diameter A2 of the inlet plugged cell 2b is larger than the hydraulic diameter A1 of the through-cell 2a in a cross section perpendicular to the cell 2 extending direction (for example, the cross section shown in FIG. 2E). It ’s big. Note that the honeycomb structure 100 has an inlet plugging that is larger than the cross-sectional area B1 of the through-cell 2a in place of the hydraulic diameter A2 of the inlet-plugged cell 2b being larger than the hydraulic diameter A1 of the through-cell 2a. The cross-sectional area B2 of the stop cell 2b may be large.

  As shown in FIGS. 4A and 4B, the other honeycomb structures 110 and 120 are preferably provided with a second honeycomb substrate 44 having porous second partition walls 41. The second partition wall 41 penetrates from the second inflow end surface 51, which is an end surface on the exhaust gas inflow side, to the second outflow end surface 52, which is the end surface on the exhaust gas outflow side, and serves as a fluid flow path. Is formed. In the present embodiment, the following configuration is a more preferable embodiment from the viewpoint of improving the collection efficiency.

  As shown in FIG. 4B, at least one other honeycomb structure 120 is arranged upstream of the honeycomb structure 100 in the exhaust gas flow direction, and the other honeycomb structure 120 is plugged. It is one preferred form to have cells 42 that are not substantially sealed at both ends by stops. In another preferred embodiment, the honeycomb structure 120 supports an oxidation catalyst. By disposing the honeycomb structure 120 without the plugging portion on the upstream side in the exhaust gas flow direction, even if the exhaust gas contains a large amount of SOF, the end face is not easily blocked, and the purification of the SOF is first performed. The soot component can be collected by the honeycomb structure 100 in the subsequent stage.

  For example, as shown to FIG. 4A, it is another preferable form that the other honeycomb structure 110 satisfy | fills the following structures. First, in the honeycomb structure 110, a part of the second cells 42 is the second in which the end portion is substantially blocked by the plugging portion 45 on the second inflow end face 51 side of the second honeycomb substrate 44. This is an inlet plugged cell 42b. And it is preferable that the remaining 2nd cell 42 is the 2nd penetration cell 42a which penetrates substantially from the 2nd inflow end surface 51 side to the outflow end surface 52 side. Furthermore, in the other honeycomb structure 110, it is preferable that the second inlet plugged cells 42b and the second through-cells 42a are arranged adjacent to each other. In the exhaust gas purifying apparatus 210 shown in FIG. 4A, the other honeycomb structure 110 has a second inflow end surface 51 facing the inlet 22 side of the storage container 21 and a second outflow end surface 52 of the storage container 21 on the outlet 23 side. It is arranged with facing. The honeycomb structure 100 is arranged with the inflow end surface 11 facing the inlet 22 side of the storage container 21 and the outflow end surface 12 facing the outlet 23 side of the storage container 21. FIG. 4A shows a third embodiment of the exhaust gas purifying apparatus of the present invention, and is a schematic view showing a cross section parallel to the flowing direction of the exhaust gas. FIG. 4B is a schematic diagram illustrating a fourth embodiment of the exhaust gas purifying apparatus of the present invention and showing a cross section parallel to the direction in which the exhaust gas flows. In the exhaust gas purifying apparatus 220 shown in FIG. 4B, the same components as those in the exhaust gas purifying apparatus 210 shown in FIG.

  When a plurality of other honeycomb structures including the honeycomb structure are arranged in the storage container so as to be arranged in series in the exhaust gas flow direction, the following configuration may be satisfied. It is. The number of plugged portions of the other honeycomb structure disposed on the upstream side is Pk, the number of plugged portions of the honeycomb structure is Pm, and the plugged portions of the other honeycomb structure disposed on the downstream side When Pn is Pn, Pk ≦ Pm or Pm ≦ Pn. When the cell density is the same and the number of plugged portions is the same, the PM flowing into the downstream honeycomb structure is reduced by the amount collected by the upstream honeycomb structure. Therefore, the amount of PM that is substantially collected is less in the downstream honeycomb structure. By satisfying the relationship of the number of plugged portions described above (that is, reducing the number of plugged portions of the honeycomb structure on the exhaust gas upstream side), it is possible to balance the collection performance on the upstream side and the downstream side. it can. Conversely, if the number of plugged portions of the upstream honeycomb structure is large, PM trapping is concentrated on the upstream honeycomb structure, which is not preferable because the cells are easily blocked. On the other hand, when the cell density is different, by configuring in this way, the cells of the other honeycomb structure disposed on the upstream side become larger, or the cells of the other honeycomb structure disposed on the downstream side become smaller. Become. This makes it difficult for other honeycomb structures disposed on the upstream side and the honeycomb structures disposed relatively upstream to be blocked by particulate matter.

  The plurality of honeycomb structures are arranged in series in the exhaust gas flow direction with the inflow end face of the honeycomb structure facing the inlet side of the storage container and the outflow end face of the honeycomb structure facing the outlet side of the storage container. It is also one of the preferable embodiments that it is arranged in the storage container so as to be lined up with each other. For example, as in the exhaust gas purification apparatus 210 shown in FIG. 4A, the honeycomb structures 100 and 110 are provided as a plurality of honeycomb structures, and the honeycomb structures 100 and 110 are connected in series in the exhaust gas flow direction in the state described above. It may be arranged in the storage container so as to line up. In this embodiment, another honeycomb structure (in other words, a third honeycomb structure) may be further provided.

  In the embodiment in which the plurality of honeycomb structures are arranged in the storage container so as to be arranged in series in the flow direction of the exhaust gas, the hydraulic diameter of the cells of each honeycomb structure satisfies the following relationship: This is one of the preferred embodiments. That is, Ak is the hydraulic diameter of the first through-cell of the honeycomb structure arranged upstream in the exhaust gas flow direction, and the hydraulic diameter of the second through-cell of the honeycomb structure arranged downstream in the exhaust gas flow direction When Am is Am, it is preferable that Ak ≧ Am. With this configuration, the honeycomb structure is less likely to be blocked by particulate matter. For example, as shown in FIG. 4A, when at least one of the other honeycomb structures 110 is arranged upstream of the honeycomb structure 100 in the flow direction of the exhaust gas G, the other honeycomb structures 110 is preferably configured as follows. That is, the hydraulic diameter A3 of the second penetration cell 42a of the other honeycomb structure 110 arranged on the upstream side is larger than the hydraulic diameter A1 of the penetration cell 2a of the honeycomb structure 100 arranged on the downstream side. Specifically, in this example, the relationship “A3 ≧ A1” is satisfied. With this configuration, the second inflow side end face 51 of the other honeycomb structure 110 is less likely to be blocked by particulate matter. However, since the collection performance of the other honeycomb structure 110 may be lower than that of the honeycomb structure 100, by disposing the honeycomb structure 100 on the downstream side of the other honeycomb structure 110, The collection performance can be improved. Since the exhaust gas G flowing into the inflow end face 11 of the honeycomb structure 100 is once collected by the other honeycomb structure 110, the amount of the particulate material contained in the exhaust gas G is small. It has become. For this reason, blockage of the inflow side end face 11 of the honeycomb structure 10 by the particulate matter is effectively suppressed. In this embodiment, the number of honeycomb structures is not limited to two, and may be three or more. For example, the hydraulic diameter of the first through cell of the honeycomb structure disposed on the most upstream side is Ak. And let the hydraulic diameter of the 2nd penetration cell of the honeycomb structure arranged next be Am. And let the hydraulic diameter of the 3rd penetration cell of the honeycomb structure arranged downstream be An. In such three honeycomb structures, it is preferable to satisfy the relationship of Ak ≧ Am or Am ≧ An.

  In the embodiment in which the plurality of honeycomb structures are arranged in the storage container so as to be arranged in series in the flow direction of the exhaust gas, the cross-sectional area of the cells of each honeycomb structure may satisfy the following relationship: This is one of the preferred embodiments. That is, the cross-sectional area of the first through cell of the honeycomb structure disposed upstream of the exhaust gas flow direction is Bk, and the cross-sectional area of the second through cell of the honeycomb structure disposed downstream of the exhaust gas flow direction Is preferably Bm, Bk ≧ Bm. With this configuration, the honeycomb structure is less likely to be blocked by particulate matter. Also in this embodiment, the number of honeycomb structures may be three or more. For example, let Bk be the cross-sectional area of the first through cell of the honeycomb structure arranged on the most upstream side. And let Bm be the cross-sectional area of the second through-cell of the honeycomb structure disposed next. And let Bn be the cross-sectional area of the third penetration cell of the honeycomb structure arranged on the downstream side. In such three honeycomb structures, it is preferable to satisfy the relationship of Bk ≧ Bm or Bm ≧ Bn.

Further, when at least one of the other honeycomb structures 110 is arranged on the upstream side in the flow direction of the exhaust gas G from the honeycomb structure 100, the other honeycomb structures 110 are configured as follows. May be. In the other honeycomb structure 110, the hydraulic diameter A4 of the second inlet plugged cell 42b is larger than the hydraulic diameter A3 of the second through-cell 42a in a cross section perpendicular to the extending direction of the second cell 42. Is more preferable. In the other honeycomb structure 110, the cross-sectional area B4 of the second inlet plugged cell 42b is larger than the cross-sectional area B3 of the second through-cell 42a in the cross section perpendicular to the extending direction of the second cell 42. There may be. Thereby, collection performance can be improved more. Further, the hydraulic diameter A4 of the hydraulic diameter A3 of the second through cell 4 2a secondary inlet plugged cell 4 2b may be the same. Further, the cross-sectional area B4 between the cross-section seat B3 of the second through cell 4 2a secondary inlet plugged cell 4 2b may be the same. Thereby, since the volume which can accumulate PM in a penetration cell is securable, it is preferable at the point which prevents the blockade by PM accumulation.

  In another honeycomb structure 110 arranged on the upstream side in the flow direction of the exhaust gas G, the hydraulic diameter A3 of the second through-cell is preferably 1.10 to 2.10 mm, and 1.20 to 1. Particularly preferred is 50 mm. By setting the hydraulic diameter A3 of the second through-cell to 1.10 mm or more, the particulate shape of the second inflow side end face 51 of the other honeycomb structure 110 (that is, the end face to be arranged on the most upstream side) It is possible to effectively suppress the end face obstruction caused by the substance. Moreover, favorable collection performance can be obtained by making hydraulic diameter A3 of a 2nd penetration cell into 2.10 mm or less. Further, by setting the hydraulic diameter A3 of the second through cell to 1.20 to 1.50 mm, the balance between the suppression of the end face obstruction and the collection performance of the honeycomb structure disposed on the downstream side is improved. By setting the hydraulic diameter A3 of the second through-cell to 1.50 mm or less, soot deposition of the honeycomb structure disposed on the upstream side increases, so that heat at the time of soot regeneration concentrates on the downstream side and melts due to excessive temperature rise. It is difficult for problems such as these to occur.

  In another honeycomb structure 110 arranged on the upstream side in the flow direction of the exhaust gas G, the hydraulic diameter A4 of the second inlet plugged cell is preferably 1.20 to 2.30 mm, and 1.30. It is especially preferable that it is -2.10mm. Furthermore, the ratio (A3 / A4) of the hydraulic diameter A3 of the second through-cell and the hydraulic diameter A4 of the second inlet plugged cell is preferably 0.9 or less, and is 0.4 to 0.9. More preferably, it is particularly preferably 0.6 to 0.8. By configuring in this way, it is possible to effectively suppress the clogging of the second inflow side end face 51 of the other honeycomb structure 110 (that is, the end face to be disposed on the most upstream side) by the particulate matter. In addition, good collection performance can be obtained. In particular, by setting the ratio (A3 / A4) to 0.4 to 0.9, the balance between the collection performance and the pressure loss is good, and by setting the ratio (A3 / A4) to 0.6 to 0.8, the upstream The soot accumulation of the honeycomb structure disposed on the side increases, so that heat at the time of soot regeneration is concentrated on the downstream side and problems such as melting due to excessive temperature rise hardly occur.

In addition, the other honeycomb structure 110 disposed on the upstream side in the flow direction of the exhaust gas G preferably has a cross-sectional area B3 of the second through cell of 1.20 to 5.30 mm ² , 1.40. More preferably, it is ˜2.70 mm ² . By comprising in this way, the end surface obstruction | occlusion by the particulate matter of the 2nd inflow side end surface 51 (namely, end surface arrange | positioned most upstream) of the other honeycomb structure 110 is suppressed effectively. Can do. Further, by making the cross-sectional area B 3 of the second through-cells in 31.20Mm ² below, it is possible to obtain a good loading performance. Further by making the cross-sectional area B 3 of the second through-cells in 1.20~5.30mm ^2, balance collection performance of the honeycomb structure disposed suppression and downstream of the end face closure is improved. By the cross-sectional area B 3 of the second through-cells within 1.40～2.70Mm ^2, collecting performance and end face closure suppressed, in addition to the balance of the pressure loss during soot deposition, the honeycomb disposed upstream Soot accumulation in the structure increases, so that heat at the time of soot regeneration is concentrated on the downstream side and problems such as melting due to excessive temperature rise are unlikely to occur.

The other honeycomb structure 110 disposed on the upstream side in the flow direction of the exhaust gas G preferably has a cross-sectional area B4 of the second inlet plugged cell of 1.40 to 6.35 mm ² . further preferably 60~5.30mm ^2. Furthermore, the ratio (B3 / B4) of the cross-sectional area B3 of the second through-cell and the cross-sectional area B4 of the second inlet plugged cell is preferably 0.2 to 0.9, 0.4 to 0 More preferably, it is .8. By configuring in this way, it is possible to effectively suppress the clogging of the second inflow side end face 51 of the other honeycomb structure 110 (that is, the end face to be disposed on the most upstream side) by the particulate matter. In addition, good collection performance can be obtained. In particular, by setting the ratio (B3 / B4) to 0.2 to 0.9, the balance between the collection performance and the pressure loss is good, and by setting the ratio (B3 / B4) to 0.4 to 0.8, the upstream Soot accumulation on the honeycomb side increases, so that heat at the time of soot concentration concentrates on the downstream side, and troubles such as melting due to excessive temperature rise hardly occur.

In the exhaust gas purification apparatus 210 of the present embodiment, the distance between the two honeycomb structures 100 and 110 adjacent to each other in the front and rear is preferably 1 to 100 mm, and more preferably 10 to 40 mm. If it is shorter than 1 mm, the adjacent honeycomb structures 100 and 110 may come into contact with each other and breakage or the like may occur. If the above-mentioned distance is longer than 100 mm, the exhaust gas purifying device 2 10 becomes large and it may be difficult to mount. And about the distance mentioned above, 10-40 mm which the plugging part of the honeycomb structure adjacent to front and back does not affect pressure loss or collection performance, and is excellent in mounting property is especially preferable.

  Further, in the exhaust gas purifying apparatus 210 of the present embodiment, the two honeycomb structures 100 and 110 are arranged in the storage container 21, but the number of honeycomb structures may be three or more. That is, it is a preferable aspect that a plurality of honeycomb structures are provided. The number of honeycomb structures can be appropriately determined according to the structure of the honeycomb structure, the properties of the exhaust gas, the emission control of particulate matter, and the like. Therefore, the number of honeycomb structures may be one or plural. The number of honeycomb structures is preferably 2 to 5. When the total volume of the honeycomb structure is the same, the collection performance is greatly improved by using two or more than one, and if the number is more than 5, the collection efficiency is sufficiently high, and the number is increased. This is because the effect of increasing the collection efficiency cannot be expected. The “total honeycomb structure volume” is the volume of one honeycomb structure in the case of one honeycomb structure, and the total volume of the plurality of honeycomb structures in the case of a plurality of honeycomb structures. That's it. Exhaust gas purification apparatus 210 according to the present embodiment has an exhaust gas purification apparatus according to the first embodiment, except that the number of honeycomb structures is two (in other words, further includes another honeycomb structure 110). It is preferable that it is comprised similarly to the apparatus 200 (refer FIG. 1).

(2) Manufacturing method of exhaust gas purification device:
The method for producing the exhaust gas purification apparatus of the present invention will be described below by taking the production method of the exhaust gas purification apparatus according to the first embodiment as an example.

(2-1) Manufacturing method of honeycomb structure:
First, a forming raw material is kneaded to form a clay. Next, the obtained clay is extruded into a honeycomb shape to obtain a honeycomb formed body. When producing a honeycomb formed body, it is preferable to perform extrusion molding so that the hydraulic diameter A2 of the cell serving as the inlet plugged cell is larger than the hydraulic diameter A1 of the cell serving as the through-cell. Next, after plugging the openings of some cells on one end face (inflow end face) of the obtained honeycomb formed body, the honeycomb structure 100 (FIGS. 2A to 2E and 3A) is fired. Reference) can be made. Here, a part of the cells to be plugged is a cell formed on the assumption that it becomes an inlet plugged cell at the time of extrusion molding. When producing a honeycomb structure carrying a catalyst, it is preferable to carry a catalyst after the firing.

  The forming raw material is preferably a ceramic raw material added with a dispersion medium and an additive. Examples of the additive include an organic binder, a pore former, and a surfactant. Examples of the dispersion medium include water.

  The ceramic raw material is selected from the group consisting of silicon carbide, silicon-silicon carbide based composite material, cordierite forming raw material, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, and aluminum titanate. It is preferable that there is at least one. Among these, a cordierite-forming raw material having a small thermal expansion coefficient and excellent thermal shock resistance is preferable.

  Examples of the organic binder include methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. It is preferable that content of an organic binder is 5-25 mass parts with respect to 100 mass parts of ceramic raw materials.

  The pore former is not particularly limited as long as it becomes pores after firing, and examples thereof include starch, foamed resin, water absorbent resin, silica gel and the like. The pore former content is preferably 10 to 20 parts by mass with respect to 100 parts by mass of the ceramic raw material.

  As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used alone or in a combination of two or more. It is preferable that content of surfactant is 3-20 mass parts with respect to 100 mass parts of ceramic raw materials.

  It is preferable that content of a dispersion medium is 10-30 mass parts with respect to 100 mass parts of ceramic raw materials.

  By adjusting the particle size and blending amount of the ceramic raw material (aggregate particles) to be used and the particle size and blending amount of the pore former to be added, a porous substrate (honeycomb substrate) having a desired porosity and average pore size Material).

  The method of kneading the forming raw material to form the kneaded material is not particularly limited, and examples thereof include a method using a kneader, a vacuum kneader or the like. Extrusion can be performed using a die having a desired cell shape, partition wall thickness, and cell density. As the material of the die, a cemented carbide which does not easily wear is preferable.

  Examples of the method of plugging the opening of the cell include a method of filling the opening of the cell with a plugging material. Specifically, as a method of filling the plugging material, first, a mask is applied to one end face of the honeycomb formed body so as to close the opening of the cell serving as the through cell. Here, the method of applying the mask is not particularly limited, but at one end face (inflow end face) of the honeycomb structure, predetermined cells whose end portions are plugged and the remaining portions where the end portions are not plugged are provided. It is preferable to apply a mask so that the cells are alternately arranged to form a checkered pattern. By the step of filling the plugging material described below to form the plugged portion, the above-described “predetermined cell with end plugged” becomes the inlet plugged cell, and the above-mentioned “end The “remaining cells whose portions are not plugged” are through-cells.

  And the slurry-like plugging material containing a ceramic raw material, water or alcohol, and an organic binder is stored in the storage container. The ceramic raw material is preferably the same as the ceramic raw material used as the raw material for the honeycomb formed body. The ceramic raw material is preferably 68 to 90% by mass of the whole plugging material. Moreover, it is preferable that water or alcohol is 8-30 mass% of the whole plugging material, and it is preferable that an organic binder is 0.1-2.0 mass% of the whole plugging material. Examples of the organic binder include hydroxypropoxyl methylcellulose and methylcellulose.

  Then, the end portion on which the mask is applied is immersed in a storage container, and a plugging material is filled into the opening of the cell where the mask is not applied to form a plugged portion. The plugging material preferably has a viscosity of 600 to 1200 Pa · s. In addition, the viscosity of the plugging material is a value measured at a rotation speed of 30 rpm with a rotary viscometer at a temperature of 30 ° C.

  The firing temperature can be appropriately determined depending on the material of the honeycomb formed body. For example, when the material of the honeycomb formed body is cordierite, the firing temperature is preferably 1380 to 1450 ° C, and more preferably 1400 to 1440 ° C. The firing time is preferably about 3 to 10 hours.

  The honeycomb formed body may be dried before firing. The drying method is not particularly limited, and examples thereof include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, etc. Among these, dielectric drying, microwave drying Or it is preferable to perform hot-air drying individually or in combination. The drying conditions are preferably a drying temperature of 30 to 150 ° C. and a drying time of 1 minute to 2 hours.

  Further, before forming the plugged portions in the honeycomb formed body, the honeycomb formed body is fired to obtain a honeycomb fired body, and the plugs are plugged into the openings of some cells on one end face of the obtained honeycomb fired body. It is also possible to obtain a honeycomb structure by further firing after forming the stopper.

  The method for supporting the catalyst on the partition walls of the honeycomb structure is not particularly limited, and examples thereof include a method of applying a catalyst slurry to the partition walls of the honeycomb structure, followed by drying and baking. The method for applying the catalyst slurry is not particularly limited, and can be applied by a known method. For example, first, a catalyst slurry containing a catalyst is prepared. Thereafter, the prepared catalyst slurry is caused to flow into the cell by dipping or suction. This catalyst slurry is preferably applied to the entire surface of the partition walls in the cell. And after making a catalyst slurry flow in in a cell, surplus slurry is blown off with compressed air. Thereafter, the catalyst slurry is dried and baked to obtain a honeycomb structure in which the catalyst is supported on the surface of the partition walls in the cell. The drying conditions are preferably 80 to 150 ° C. and 1 to 6 hours. Moreover, it is preferable that baking conditions shall be 450-700 degreeC and 0.5 to 6 hours. In addition, alumina etc. are mentioned as components other than the catalyst contained in a catalyst slurry.

(2-2) Manufacturing method of exhaust gas purification device:
It is preferable to obtain the exhaust gas purification apparatus 200 by winding the cushion 31 material around the outer periphery of the obtained honeycomb structure 100 and press-fitting the honeycomb structure 100 around which the cushion material 31 is wound into the storage container 21. (See FIG. 1).

  As described above, when the honeycomb structure 100 is stored in the storage container 21 with the cushion material 31 wound, the honeycomb structure 100 can be prevented from moving in the storage container 21. Examples of the cushion material 31 include a heat-resistant inorganic insulating mat.

  The storage container 21 can be produced by a known method. For example, it can be produced by pressing a plate material made of ferritic stainless steel and welding the pressed plate material. The conditions such as the shape and size of the storage container are preferably those that are preferable in the first embodiment of the exhaust gas purifying apparatus of the present invention.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

Example 1
(Honeycomb structure)
First, 13 parts by mass of a pore former, 35 parts by mass of a dispersion medium, 6 parts by mass of an organic binder, and 0.5 parts by mass of a dispersant are added to 100 parts by mass of a cordierite forming raw material, and mixed and kneaded. A clay was prepared. As the cordierite forming raw material, alumina, aluminum hydroxide, kaolin, talc, and silica were used. Water was used as the dispersion medium, coke having an average particle diameter of 1 to 10 μm was used as the pore former, hydroxypropylmethylcellulose was used as the organic binder, and ethylene glycol was used as the dispersant. By controlling the particle diameter and amount of the pore former, the pore diameter and porosity of the partition walls were controlled.

  Next, the kneaded material was extruded using a predetermined mold to obtain a honeycomb formed body having a square cell shape and a columnar overall shape. As shown in FIG. 5, in the honeycomb formed body, in the honeycomb structure after firing, the hydraulic diameter A1 of the cell 2 that becomes the penetrating cell 2a is 0.90 mm, and the hydraulic diameter of the cell 2 that becomes the inlet plugged cell 2b It was fabricated so that A2 was 1.30 mm. Here, FIG. 5 is a schematic diagram showing the cell shape of the honeycomb structure constituting the exhaust gas purification apparatus of Example 1. FIG. As shown in FIG. 5, the cell 2 that becomes the penetrating cell 2 a and the cell 2 that becomes the inlet plugged cell 2 b are arranged adjacent to each other with the partition wall 1 therebetween.

  Next, the honeycomb formed body was dried with a microwave dryer and further completely dried with a hot air dryer, and then both end faces of the honeycomb formed body were cut and adjusted to a predetermined size. Next, a mask was applied to an opening of a part of cells (cells to be the through-cells 2a in FIG. 5) on one end face (inflow end face) of the honeycomb formed body. By immersing the end portion on the side where the mask was applied into a plugging slurry containing a cordierite forming raw material, the plugging slurry was filled into predetermined cells (cells where no mask was applied) on the inflow end surface. The cell filled with the plugging slurry in this manner is a cell that becomes the inlet plugged cell 2b in FIG. Thereby, the inlet plugged cells in which the plugged portions are formed on the inflow end surface and the penetrating cells in which both ends are opened are alternately arranged. On the inflow end surface, the “plugged portions” and the “cell plugs” are arranged. A honeycomb formed body in which a checkered pattern was formed by the “opening” was obtained. Thereafter, the honeycomb formed body on which the plugged portions are formed is dried with a hot air drier, and further fired at 1410 to 1440 ° C. for 5 hours, so that the plugged portions are not formed at the outflow side end portions. A honeycomb structure having a plugged portion formed at the inflow side end was obtained.

The obtained honeycomb structure had a cylindrical shape with a diameter of a cross section perpendicular to the central axis of 191 mm and a length in the central axis direction of 80 mm. The cell density of the obtained honeycomb structure was 46.5 cells / cm ² , the partition wall thickness was 0.3 mm, the partition wall porosity was 58%, and the partition wall average pore diameter was 22 μm. It was. In addition, “a value obtained by subtracting the depth of the plugged portion from the length in the cell extending direction of the honeycomb structure” (length excluding the plugged portion (mm)) was 70 mm. The porosity of the partition walls and the average pore diameter of the partition walls were measured with a mercury porosimeter. The “thickness of the partition wall” was measured using a scanning electron microscope (SEM).

(Exhaust gas purification device)
The obtained honeycomb structure was stored in a metal (specifically, ferritic stainless steel) storage container having an inlet and an outlet provided with a partition plate having a thickness of 2 mm. An exhaust gas purification apparatus 200 as shown in FIG. At the time of storage, the outer periphery of the honeycomb structure was covered with a mat mainly composed of ceramic fibers, and in that state, it was press-fitted into the storage container and fixed. The honeycomb structure was disposed in the storage container such that the inflow end surface where the plugging portions are disposed faces the upstream side (inlet side of the storage container).

  About the obtained exhaust gas purification apparatus, “collection efficiency” and “collection efficiency after 1500 hours of engine operation” were measured by the following methods. The results of “collection efficiency” and “collection efficiency after 1500 hours of engine operation” are shown in FIGS. 11 to 13 are graphs showing the measurement results of the collection efficiency. In the collection efficiency test, the amount of particulate matter (PM) deposited in the honeycomb structure increases from the start of the test, and the collection efficiency changes as the amount of particulate matter deposited increases. 11 to 13 are graphs in which the accumulation amount of the particulate matter is taken on the horizontal axis, and the collection efficiency when the accumulation amount is obtained is taken on the vertical axis. FIG. 11 is a graph showing the measurement results of the collection efficiency for the exhaust gas purification apparatuses of Examples 1 and 2 and Comparative Examples 1 and 2. FIG. 12 is a graph showing the measurement results of the collection efficiency for the exhaust gas purification apparatuses of Examples 3 to 6 and Comparative Examples 1 and 2. FIG. 13 is a graph showing the measurement results of the collection efficiency for the exhaust gas purification apparatuses of Examples 7 to 9 and Comparative Examples 1 and 2. Further, the unit “g / PM deposition amount (mass) per honeycomb structure” on the horizontal axis (PM deposition amount) in FIGS.

  Further, the structural characteristics of the obtained exhaust gas purification apparatus are shown in Table 1. Table 1 shows structural features of the exhaust gas purifying apparatuses of Examples 1 to 9 and Comparative Examples 1 and 2. In Table 1, the “diameter” column indicates the diameter in the “cross section perpendicular to the cell extending direction” of the honeycomb structure. The column “length excluding plugged portions (mm)” indicates a value (mm) obtained by subtracting the depth of the plugged portion from the length in the cell extending direction of the honeycomb structure. The “number” column indicates the number of honeycomb structures arranged in the storage container of the exhaust gas purification apparatus. When the “number” is “2”, it means that two honeycomb structures are arranged in series in the storage container. Further, when the “number” is “3”, it means that three honeycomb structures are arranged in series in the storage container. Two or three honeycomb structures are honeycomb structures having the same structure.

  In Table 1, the “porosity” column indicates the porosity of the partition walls of the honeycomb structure. The column of “average pore diameter” indicates the average pore diameter of the partition walls of the honeycomb structure. The porosity and average pore diameter are values measured with a mercury porosimeter. The column of “partition wall thickness” indicates the partition wall thickness of the honeycomb structure. The column “Hydraulic diameter A1 of the penetrating cell” indicates the value of the hydraulic diameter A1 of the penetrating cell among the cells formed in the honeycomb structure. The column of “hydraulic diameter A2 of the inlet plugged cell” indicates the value of the hydraulic diameter A2 of the inlet plugged cell among the cells formed in the honeycomb structure. The column of “hydraulic diameter ratio (A1 / A2)” indicates the value of the ratio between the hydraulic diameter A1 of the penetrating cell and the hydraulic diameter A2 of the inlet plugged cell. The column “cross-sectional area B1 of the through-cell” indicates the value of the cross-sectional area B1 of the through-cell among the cells formed in the honeycomb structure. The column of “cross-sectional area B2 of the inlet plugged cells” indicates the value of the cross-sectional area B2 of the inlet plugged cells among the cells formed in the honeycomb structure. The column “Cross-sectional area ratio (B1 / B2)” indicates the value of the ratio between the cross-sectional area B1 of the penetrating cell and the cross-sectional area B2 of the inlet plugged cell. In the column of “Oxidation catalyst”, “None” indicates that no oxidation catalyst is supported on the honeycomb structure, and “Yes” indicates that an oxidation catalyst is supported on the honeycomb structure. The “plugging position” indicates whether a plugged portion is disposed on the inflow end surface of the honeycomb structure or a plugged portion is disposed on the outflow end surface.

(Collection efficiency)
Combustion gas is generated using a burner that uses light oil as fuel. A predetermined amount of air is mixed with the combustion gas so that the flow rate of the entire gas is 1.5 Nm ³ / min, and the obtained mixed gas is introduced into the exhaust gas purification device. The temperature of the mixed gas is 200 ° C. The test time is 120 minutes. Further, the concentration of the particulate matter in the mixed gas is set to 4 g / hour. The collection efficiency is calculated by the following method. While introducing the mixed gas into the exhaust gas purification device, the exhaust gas is sampled for about 2 minutes by a vacuum pump from sampling pipes provided on the upstream side and the downstream side of the exhaust gas purification device. Then, when sampling the exhaust gas, PM is collected on the filter paper by passing the exhaust gas through a holder in which the filter paper is set. In addition, the mass of the filter paper is measured in advance. The mass of PM in the exhaust gas sampled from the upstream side of the exhaust gas purification device (the mass of PM collected on the filter paper) and the mass of PM in the exhaust gas sampled from the downstream side of the exhaust gas purification device (collected on the filter paper) The collection efficiency is calculated from the mass of PM). Specifically, “collection efficiency (%) = 100 × (PM mass collected on filter paper from upstream side of exhaust gas purification device (g)) − PM mass collected on filter paper from downstream side of exhaust gas purification device (G)) / PM mass (g) collected on filter paper from upstream side of exhaust gas purifying apparatus ”.

(Collection efficiency after 1500 hours of engine operation)
An exhaust gas purification device is installed in the exhaust pipe of a diesel engine, and is operated for 1500 hours in an NRTC (Non-Road Transient Cycle) mode. Thereafter, the “collection efficiency” is measured.

(Comparative Example 1)
As shown in FIG. 6, in the honeycomb structure, the hydraulic diameter A1 of the cell 62 that becomes the penetrating cell 62a is 1.10 mm, and the hydraulic diameter A2 of the cell 62 that becomes the inlet plugged cell 62b is 1.10 mm. It was prepared. Here, FIG. 6 is a schematic diagram showing the cell shape of the honeycomb structure constituting the exhaust gas purification apparatus of Comparative Example 1. FIG. As shown in FIG. 6, a cell 62 to be a through cell 62 a and a cell 62 to be an inlet plugged cell 62 b are arranged adjacent to each other with a partition wall 61 therebetween. An exhaust gas purification apparatus was produced in the same manner as in Example 1 except that such a honeycomb structure was disposed in the storage container. The “collection efficiency” was measured by the above method. The results are shown in FIGS.

(Example 2)
As shown in FIG. 7, in the honeycomb structure, the hydraulic diameter A1 of the cell 2 serving as the penetrating cell 2a is 0.92 mm, and the hydraulic diameter A2 of the cell 2 serving as the inlet plugged cell 2b is 1.46 mm. It was prepared. Here, FIG. 7 is a schematic view showing the cell shape of the honeycomb structure constituting the exhaust gas purification apparatus of Example 2. FIG. An exhaust gas purification apparatus was produced in the same manner as in Example 1 except that such a honeycomb structure was disposed in the storage container. The “collection efficiency” was measured by the above method. The results are shown in FIG.

(Example 3)
As shown in FIG. 8, in the honeycomb structure, the hydraulic diameter A1 of the cell 2 serving as the penetrating cell 2a is 0.90 mm, and the hydraulic diameter A2 of the cell 2 serving as the inlet plugged cell 2b is 1.10 mm. It was prepared. In Example 3, the shape of the penetrating cell 2a is a small rectangle that is wide in the left-right direction of the paper surface of FIG. 8, and the shape of the inlet plugged cell 2b is a large rectangle that is wide in the vertical direction of the paper surface of FIG. is there. Here, FIG. 8 is a schematic diagram showing the cell shape of the honeycomb structure constituting the exhaust gas purification apparatus of Example 3. FIG. An exhaust gas purification apparatus was produced in the same manner as in Example 1 except that such a honeycomb structure was disposed in the storage container. The “collection efficiency” was measured by the above method. The results are shown in FIG.

Example 4
As shown in FIG. 9, in the honeycomb structure, the hydraulic diameter A1 of the cell 2 that becomes the penetrating cell 2a is 1.10 mm, and the hydraulic diameter A2 of the cell 2 that becomes the inlet plugged cell 2b is 1.50 mm. It was prepared. In the fourth embodiment, the sizes of the penetrating cell 2a and the inlet plugged cell 2b are larger than those of the first embodiment. Here, FIG. 9 is a schematic view showing the cell shape of the honeycomb structure constituting the exhaust gas purification apparatus of Example 4. FIG. An exhaust gas purification apparatus was produced in the same manner as in Example 1 except that such a honeycomb structure was disposed in the storage container. The “collection efficiency” was measured by the above method. The results are shown in FIG.

(Comparative Example 2)
As shown in FIG. 10, in the honeycomb structure, the hydraulic diameter A1 of the cell 72 that becomes the penetrating cell 72a is 1.20 mm, and the hydraulic diameter A2 of the cell 72 that becomes the inlet plugged cell 72b is 1.00 mm. It was prepared. Here, FIG. 10 is a schematic diagram showing the cell shape of the honeycomb structure constituting the exhaust gas purification apparatus of Comparative Example 2. An exhaust gas purification apparatus was produced in the same manner as in Example 1 except that such a honeycomb structure was disposed in the storage container. The “collection efficiency” was measured by the above method. The results are shown in FIGS.

(Example 5)
An exhaust gas purification apparatus was produced in the same manner as in Example 1 except that two honeycomb structures were housed in series in the housing container. The “collection efficiency” was measured by the above method. The results are shown in FIG.

(Example 6)
An exhaust gas purification apparatus was produced in the same manner as in Example 1 except that three honeycomb structures were housed in series in the storage container. The “collection efficiency” was measured by the above method. The results are shown in FIG.

(Examples 7 to 9)
Exhaust gas purification apparatus was produced in the same manner as in Example 1 except that the configuration of the honeycomb structure was changed as shown in Table 1. The “collection efficiency” was measured by the above method. The results are shown in FIG.

(result)
From FIG. 11 to FIG. 13, it can be seen that the exhaust gas purification devices of Examples 1 to 9 have significantly improved collection efficiency as compared with the exhaust gas purification devices of Comparative Examples 1 and 2. That is, it is possible to improve the collection efficiency by using a honeycomb structure in which the hydraulic diameter A2 of the inlet plugged cell is larger than the hydraulic diameter A1 of the penetration cell in the exhaust gas purification device. Moreover, even when a honeycomb structure having a cross-sectional area B2 of the inlet plugged cell larger than the cross-sectional area B1 of the through-cell is used in the exhaust gas purification device, the collection efficiency can be improved. Furthermore, it can be seen that in the exhaust gas purifying apparatuses of Examples 1 to 9, the collection efficiency is not lowered even when the amount of accumulated PM increases.

  In addition, it can be seen from FIG. 12 that the collection efficiency of the exhaust gas purification apparatuses of Examples 5 and 6 is significantly improved. Thus, in the exhaust gas purification apparatus of this invention, it turned out that collection efficiency can further be improved by arrange | positioning two or more honeycomb structures in series. From FIG. 13, if the hydraulic diameter A2 of the inlet plugged cell is larger than the hydraulic diameter A1 of the through-cell, the ratio of the hydraulic diameter A2 of the inlet plugged cell to the hydraulic diameter A1 of the through-cell is Even if it changed, the improvement effect of the collection efficiency could be maintained.

  The exhaust gas purifying apparatus of the present invention can be suitably used as a carrier for a catalytic device or a filter used for environmental measures or recovery of specific materials in various fields such as chemistry, electric power, and steel. In particular, it can be suitably used for purification of exhaust gas.

1: partition wall, 2: cell, 2a: penetration cell, 2b: inlet plugged cell, 3: outer peripheral wall, 4: honeycomb substrate, 5: plugged portion, 11: inflow end surface, 12: outflow end surface, 13 : Particulate matter, 21: storage container, 22: inlet, 23: outlet, 31: cushioning material, 32: fastener, 41: second partition, 42: second cell, 42a: second penetration cell, 42b : Second inlet plugged cell, 43: second outer peripheral wall, 44: second honeycomb substrate, 45: plugged portion, 51: second inflow end surface, 52: second outflow end surface, 61, 71: partition wall 62, 72: cells, 62a, 72a: through cells, 62b, 72b: inlet plugged cells, 100: honeycomb structure, 110, 120: honeycomb structures (other honeycomb structures), 200, 210, 220 : Exhaust gas purification device, G: exhaust gas.

Claims (14)

A honeycomb substrate having a porous partition wall that penetrates from an inflow end surface that is an end surface on the exhaust gas inflow side to an outflow end surface that is an end surface on the exhaust gas outflow side to form a plurality of cells that serve as fluid flow paths. A part of the cells are inlet plugged cells whose ends are substantially plugged by plugged portions on the inflow end face side of the honeycomb substrate, and the remaining cells are the It is a through cell that penetrates substantially from the inflow end surface side to the outflow end surface side, the inlet plugged cell and the through cell are disposed adjacent to each other, and in a cross section perpendicular to the extending direction of the cell, A honeycomb structure in which a hydraulic diameter A2 of the inlet plugged cell is larger than a hydraulic diameter A1 of the penetration cell;
A cylindrical storage container having an inflow port through which exhaust gas flows in and an outflow port through which purified exhaust gas flows out, in which the honeycomb structure is stored,
The exhaust gas purifying apparatus, wherein the honeycomb structure is disposed in the storage container such that the inflow end surface faces the inflow port side of the storage container and the outflow end surface faces the outflow side of the storage container. .   The exhaust gas purification apparatus according to claim 1, wherein a ratio (A1 / A2) of a hydraulic diameter A1 of the through-cell and a hydraulic diameter A2 of the inlet plugged cell is 0.9 or less.   The exhaust gas purification apparatus according to claim 1 or 2, wherein a hydraulic diameter A1 of the through cell is 0.7 to 2.1 mm.   The exhaust gas purification apparatus according to any one of claims 1 to 3, wherein a hydraulic diameter A2 of the inlet plugged cell is 0.8 to 3.0 mm. A honeycomb substrate having a porous partition wall that penetrates from an inflow end surface that is an end surface on the exhaust gas inflow side to an outflow end surface that is an end surface on the exhaust gas outflow side to form a plurality of cells that serve as fluid flow paths. A part of the cells are inlet plugged cells whose ends are substantially plugged by plugged portions on the inflow end face side of the honeycomb substrate, and the remaining cells are the It is a through cell that penetrates substantially from the inflow end surface side to the outflow end surface side, the inlet plugged cell and the through cell are disposed adjacent to each other, and in a cross section perpendicular to the extending direction of the cell, A honeycomb structure in which a cross-sectional area B2 of the inlet plugged cell is larger than a cross-sectional area B1 of the penetrating cell;
A cylindrical storage container having an inflow port through which exhaust gas flows in and an outflow port through which purified exhaust gas flows out, in which the honeycomb structure is stored,
The exhaust gas purifying apparatus, wherein the honeycomb structure is disposed in the storage container such that the inflow end surface faces the inflow port side of the storage container and the outflow end surface faces the outflow side of the storage container. .   The exhaust gas purification apparatus according to claim 5, wherein a ratio (B1 / B2) of a cross-sectional area B1 of the through-cell and a cross-sectional area B2 of the inlet plugged cell is 0.9 or less. The exhaust gas purification apparatus according to claim 5 or 6, wherein a cross-sectional area B1 of the through cell is 0.49 to 5.30 mm ² . The cross-sectional area B2 of the inlet plugged cells, is 0.64～9.00Mm ^2, the exhaust gas purifying apparatus according to any one of claims 5-7.   The honeycomb structure is disposed such that the inflow end surface of the honeycomb structure faces the inflow side of the storage container and the outflow end surface of the honeycomb structure faces the outflow side of the storage container. On the other hand, the storage container further includes at least one other honeycomb structure, and the other honeycomb structure is arranged in series in the exhaust gas flow direction with respect to the honeycomb structure. The exhaust gas purification apparatus according to any one of claims 1 to 8, wherein the exhaust gas purification apparatus is disposed.   At least one of the other honeycomb structures is disposed upstream of the honeycomb structure in the exhaust gas flow direction, and both ends of the other honeycomb structures are substantially plugged by plugging portions. The exhaust gas purification apparatus according to claim 9, further comprising a cell not sealed. A plurality of other honeycomb structures including the honeycomb structure are arranged in the storage container so as to be arranged in series in the flow direction of the exhaust gas, and the other honeycomb structures arranged upstream are plugged. Pk ≦ Pm, where Pk is the number of plugged portions, Pm is the number of plugged portions of the honeycomb structure, and Pn is the number of plugged portions of the other honeycomb structure disposed downstream. The exhaust gas purification apparatus according to any one of claims 1 to 8 , wherein Pm ≦ Pn.   In the plurality of honeycomb structures, the inflow end face of the honeycomb structure faces the inlet side of the storage container and the outflow end face of the honeycomb structure faces the outlet side of the storage container. And the exhaust gas purification apparatus as described in any one of Claims 1-11 arrange | positioned in the said storage container so that it may rank in series in the flow direction of waste gas.   The plurality of honeycomb structures are arranged in the storage container so as to be arranged in series in the exhaust gas flow direction, and the hydraulic diameter of the first through-cells of the honeycomb structure arranged on the upstream side in the exhaust gas flow direction Is Ak, where Ak ≧ Am, where Ak is the hydraulic diameter of the second through-cell of the honeycomb structure disposed downstream of the exhaust gas flow direction. The exhaust gas purification apparatus as described.   A plurality of honeycomb structures are arranged in the storage container so as to be arranged in series in the exhaust gas flow direction, and a cross-sectional area of the first through-cells of the honeycomb structure arranged on the upstream side in the exhaust gas flow direction Is Bk, and Bk ≧ Bm, where Bk is the cross-sectional area of the second through-cell of the honeycomb structure disposed on the downstream side in the exhaust gas flow direction. The exhaust gas purification apparatus as described.

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