Cellular filter and exhaust gas treatment system

Abstract

The utility model provides a kind of honeycomb filter and waste gas treatment system, can inhibit the increase of pressure loss while inhibiting the passage of particulate matter.A kind of honeycomb filter (1), it is characterized in that, with it has: honeycomb structure part (2), it has outer peripheral wall (20) and partition wall (21), the partition wall is equipped in the inside of outer peripheral wall (20) and is divided to form multiple compartments (22), the multiple compartments form flow path extending from first end surface (2a) to second end surface (2b);And sealing portion (3), it is arranged in compartment (22) in either party of first end surface (2a) and second end surface (2b), compartment (22) includes at least one incomplete sealing compartment (4), the incomplete sealing compartment is formed with opening (3a) in sealing portion (3), when irradiating light in either party of first end surface (2a) and second end surface (2b), can be confirmed to light leakage in the other party of first end surface (2a) and second end surface (2b).

Description

Technical Field

[0001] This utility model relates to a honeycomb filter and an exhaust gas treatment system. Background Technology

[0002] As a mechanism for reducing the amount of particulate matter contained in the exhaust gas from an internal combustion engine, a particulate filter is installed in the exhaust gas flow path to capture particulate matter. In recent years, due to the stricter restrictions on the number of exhaust particles, particulate filters with high capture efficiency have been used, but conversely, the pressure loss of the particulate filter has increased.

[0003] Patent documents 1-4 disclose honeycomb filters that use sealed compartments as particulate filters as described above. In particular, patent documents 1 and 4 disclose the omission of sealing holes in specific compartments located on the outer periphery. By omitting the sealing holes, pressure loss can be reduced.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-183360

[0007] Patent Document 2: Japanese Patent Application Publication No. 2012-210581

[0008] Patent Document 3: Japanese Patent Application Publication No. 2013-163155

[0009] Patent Document 4: International Publication No. 2013 / 136848 Utility Model Content

[0010] The problem to be solved by the utility model

[0011] In previous configurations, the capture efficiency of particulate matter was sometimes reduced when the sealed compartments were omitted.

[0012] This invention was made to solve the aforementioned problems, and one of its objectives is to provide a honeycomb filter and exhaust gas treatment system that can suppress the passage of particulate matter while suppressing the increase in pressure loss.

[0013] Solution for solving the problem

[0014] [1] The first item of this utility model relates to a honeycomb filter, characterized in that it comprises: a honeycomb structure having an outer peripheral wall and a partition wall, the partition wall being disposed on the inner side of the outer peripheral wall and dividing to form a plurality of compartments, the plurality of compartments forming a flow path extending from a first end face to a second end face; and a sealing portion disposed in the compartment on either the first end face or the second end face, the compartment including at least one partially sealed compartment having an opening formed in the sealing portion, such that when light is irradiated onto either the first end face or the second end face, light leakage can be detected on the other end face.

[0015] [2] The second item of this utility model may relate to the honeycomb filter described in the first item, characterized in that the ratio of the total area of ​​the openings in the partially sealed compartments to the total area of ​​the partially sealed compartments in a cross section of the honeycomb structure orthogonal to the direction in which the compartments extend is 5% or more and 90% or less.

[0016] [3] The third item of this utility model may relate to the honeycomb filter described in the second item, characterized in that the ratio of the total area of ​​the openings in all the partially sealed compartments to the total area of ​​all the compartments in a cross section of the honeycomb structure orthogonal to the direction in which the compartments extend is 1400 ppm or less.

[0017] [4] The fourth item of this utility model may relate to a honeycomb filter in any one of items 1 to 3, characterized in that the compartment comprises a plurality of normal compartments disposed away from the outer peripheral wall, and a plurality of partial compartments disposed adjacent to the outer peripheral wall and having a partial cross-sectional shape relative to the plurality of normal compartments, wherein at least one incompletely sealed compartment is disposed in the plurality of partial compartments.

[0018] [5] The fifth item of this utility model may relate to the honeycomb filter of any one of items 1 to 3, characterized in that the porosity of the partition is 45% or more and 70% or less, and the thickness of the partition is 127 μm or more and 254 μm or less.

[0019] [6] The sixth item of this utility model relates to an exhaust gas treatment system, characterized in that it comprises a honeycomb filter as described in any one of items 1 to 3, the honeycomb filter being configured to allow exhaust gas to pass through the compartment.

[0020] Utility Model Effect

[0021] According to one embodiment of the honeycomb filter and exhaust gas treatment system of the present invention, an opening is formed in the sealing portion, and the compartment includes at least one incompletely sealed compartment in which light leakage can be detected in the other of the first end face and the second end face when light is irradiated to either of the first end face and the second end face. Therefore, it is possible to suppress the passage of particulate matter while suppressing the increase in pressure loss. Attached Figure Description

[0022] Figure 1 This is a front view of a honeycomb filter representing an embodiment of the present invention.

[0023] Figure 2 It is along Figure 1 A cross-sectional view of the cell filter in line II-II.

[0024] Figure 3 It means Figure 1 A magnified view of region III.

[0025] Figure 4 This is an illustrative diagram illustrating a test method for determining whether an incompletely sealed vent chamber is present.

[0026] Figure 5 This is a cross-sectional view of the waste gas treatment system according to an embodiment of this utility model.

[0027] Figure 6 This is a graph showing the relationship between the percentage of the perforated area in the overall embodiment and the rate of reduction in capture efficiency in the comparative examples. Detailed Implementation

[0028] Hereinafter, embodiments for implementing this utility model will be described with reference to the accompanying drawings. This utility model is not limited to any particular embodiment, and can be embodied by modifying the constituent elements without departing from its spirit. Furthermore, various utility models can be formed by appropriately combining the multiple constituent elements disclosed in each embodiment. For example, several constituent elements may be deleted from all the constituent elements shown in the embodiments. Moreover, constituent elements from different embodiments may be appropriately combined.

[0029] Implementation

[0030] Figure 1 This is a front view showing an embodiment of the honeycomb filter 1 of this utility model. Figure 2 It is along Figure 1 A cross-sectional view of the cell filter 1 in line II-II. Figure 3 It means Figure 1 An enlarged view of region III, Figure 4 It is an illustrative indication of whether a setting is provided. Figure 3 A diagram illustrating the test method for the incompletely sealed compartment 4.

[0031] like Figure 1 and Figure 2 As shown, the honeycomb filter 1 has a honeycomb structure part 2 and a sealing part 3.

[0032] The honeycomb structure 2 has an outer peripheral wall 20 and a partition wall 21 disposed on the inner side of the outer peripheral wall 20. The partition wall 21 divides into a plurality of compartments 22. The plurality of compartments 22 form a flow path extending from the first end face 2a to the second end face 2b of the honeycomb structure 2.

[0033] A sealing portion 3 is disposed on either the first end face 2a or the second end face 2b in the compartment 22. The sealing portion 3 seals the compartment 22. Regarding the sealing, the compartment 22 includes a first compartment 221 that is open on the first end face 2a and sealed on the second end face 2b, and a second compartment 222 that is open on the second end face 2b and sealed on the first end face 2a. The first compartment 221 and the second compartment 222 may be alternately arranged in a direction orthogonal to the direction in which the compartment 22 extends.

[0034] As will be described later, the honeycomb filter 1 can be configured in the exhaust gas treatment system 5 such that exhaust gas 5a passes through compartment 22 (see reference). Figure 5 Exhaust gas 5a can enter the first compartment 221 from the first end face 2a, pass through the partition wall 21 between the first compartment 221 and the second compartment 222, and exit from the second compartment 222 at the second end face 2b. Therefore, the honeycomb filter 1 can be considered a wall-flow type. When exhaust gas 5a passes through the partition wall 21, particulate matter in exhaust gas 5a cannot pass through the partition wall 21 and remains in the first compartment 221. In the exhaust gas treatment system 5, the honeycomb filter 1 can at least capture particulate matter in exhaust gas 5a and purify exhaust gas 5a.

[0035] like Figure 3 As shown, compartment 22 includes at least one partially sealed compartment 4 with an opening 3a formed in the sealing portion 3. The partially sealed compartment 4 is configured such that when light is irradiated onto either the first end face 2a or the second end face 2b, light leakage can be detected on the other end face 2b. In the partially sealed compartment 4, the sealing portion 3 does not completely seal the openings of compartment 22 in the first end face 2a and the second end face 2b, but rather stops at narrowing the openings of compartment 22 in the first end face 2a and the second end face 2b.

[0036] pass Figure 4The test method shown determines whether a compartment 22 with a sealing portion 3 is an incompletely sealed compartment 4. Specifically, a honeycomb filter 1 is disposed on a light box 6. The light box 6 has a frame 60, a light source 61 disposed inside the frame 60, and a cover 62 disposed on the frame 60 such that it is positioned above the light source 61 and allows light from the light source 61 to pass through. The honeycomb filter 1 is disposed on the light box 6 such that either the first end face 2a or the second end face 2b contacts the cover 62. Light from the light source 61 is irradiated through the cover 62 towards either the first end face 2a or the second end face 2b, and it is confirmed whether light leakage occurs from the other end face 2a or the second end face 2b. Furthermore, if light leakage is confirmed in either compartment 22, that compartment 22 is determined to be an incompletely sealed compartment 4. Figure 4 This illustrates a configuration where the honeycomb filter 1 is positioned so that its first end face 2a contacts the cover portion 62, and the light leakage at the second end face 2b is visually confirmed. Furthermore, the illuminance from the light source is preferably 5000 lux or higher.

[0037] The sealing portion 3 is disposed in either the first end face 2a or the second end face 2b within the compartment 22. In other words, all compartments 22 are either the first compartment 221 or the second compartment 222. Assuming that no opening 3a is formed in the sealing portion 3 in any of the compartments 22, when light is shone onto either the first end face 2a or the second end face 2b, light leakage cannot be detected on the other end face 2b. Normally, the sealing portion 3 does not transmit light. Light leakage does not include cases where light attenuation at the sealing portion 3 can be observed. In cases where light attenuation at the sealing portion 3 is observed on the other end face 2a or the second end face 2b, whether light leakage can be confirmed is determined based on the brightness of the light observed on the other end face 2a or the second end face 2b. If light is significantly brighter than other parts when observed visually, it is determined that light leakage can be confirmed.

[0038] As described above, in the exhaust gas treatment system 5, the honeycomb filter 1 captures particulate matter in the exhaust gas 5a. In recent years, due to stricter restrictions on the number of particles in the exhaust gas 5a, the capture efficiency of the honeycomb filter 1 has increased, but conversely, the pressure loss of the honeycomb filter 1 has increased. As in Patent Documents 1 and 4, in order to suppress the increase in pressure loss, it is considered to omit the sealing holes (not providing the sealing portion 3) in a specific compartment 22 located on the outer periphery. However, sometimes particulate matter passes through the compartment 22 without the sealing holes, resulting in a lower capture efficiency for the particulate matter. In this embodiment, by providing a partially sealed compartment 4 with an opening 3a formed in the sealing portion 3, it is possible to suppress the passage of particulate matter while suppressing the increase in pressure loss.

[0039] Furthermore, during the manufacture of the honeycomb filter 1, a sealing portion 3 can be formed on the end face of the blank of the honeycomb filter 1 (the honeycomb molded body described later) in a compartment 22 to which a mask has been applied. By intentionally omitting the mask from the compartment 22, which would otherwise be masked, it is possible to form a compartment 22 without a sealing hole, as in Patent Documents 1 and 4. In contrast, after applying a mask, by partially opening holes in the mask, it is possible to create an opening 3a in the sealing portion 3 due to insufficient filling of the sealing hole. By controlling the size and position of the holes opened in the mask, the size of the opening 3a in the incompletely sealed compartment 4 can be controlled.

[0040] The ratio of the total area of ​​the openings 3a in these partially sealed compartments 4 to the total area of ​​the partially sealed compartments 4 in a cross-section of the honeycomb structure 2 orthogonal to the direction in which the compartments 22 extend is preferably 5% or more and 90% or less. A ratio of 5% or more allows for more reliable suppression of increased pressure loss. A ratio of 90% or less allows for more reliable suppression of the passage of particulate matter. The area of ​​the openings 3a is determined by image analysis of the first end face 2a or the second end face 2b. The area of ​​the partially sealed compartments 4 in a cross-section of the honeycomb structure 2 orthogonal to the direction in which the compartments 22 extend is determined by image analysis of that cross-section. Images are taken using a camera with a pixel resolution of 40 μm / pixel or less. The honeycomb structure 2 and the sealed compartments 3 are separated from the openings 3a by binarization processing, and their respective areas are determined.

[0041] Preferably, the ratio of the total area of ​​the openings 3a in all the partially sealed compartments 4 to the total area of ​​all compartments 22 in a cross-section of the honeycomb structure 2 orthogonal to the direction in which the compartments 22 extend is 1400 ppm or less. A ratio of 1400 ppm or less allows for more reliable suppression of the passage of particulate matter. More preferably, this ratio is 1337 ppm or less. This ratio is preferably 70 ppm or more. A ratio of 70 ppm or more facilitates a reduction in pressure loss.

[0042] like Figure 1 As shown, compartment 22 includes a plurality of general compartments 23 disposed away from the outer peripheral wall 20, and a plurality of partial compartments 24 disposed adjacent to the outer peripheral wall 20 and having a partial cross-sectional shape relative to the plurality of general compartments 23. In the illustrated configuration, the general compartments 23 are square in shape. In contrast, the partial compartments 24 are shaped such that the outer side of the circle formed by the inner edge of the outer peripheral wall 20 in the square is cut off.

[0043] Preferably, at least one partially sealed compartment 4 is provided in one of the multiple partial compartments 24. This allows for suppression of the permeation of particulate matter compared to a normal compartment 23. The partially sealed compartment 4 may be provided in one of the normal compartments 23, or it may not be provided in one of the normal compartments 23. Alternatively, the partially sealed compartment 4 may be provided only in one of the multiple partial compartments 24.

[0044] Preferably, the porosity of the partition wall 21 is 45% or more and 70% or less, and the thickness of the partition wall 21 is 127 μm or more and 254 μm or less. A porosity of 45% or more in the partition wall 21 helps to suppress the increase in pressure loss, while a porosity of 70% or less reduces the possibility of the honeycomb filter 1 becoming brittle and detaching. The porosity is a value measured using a mercury porosity meter. A thickness of 127 μm or more in the partition wall 21 reduces the possibility of a decrease in the strength of the honeycomb filter 1, while a thickness of 254 μm or less reduces the possibility of an increase in pressure loss when exhaust gas 5a passes through the compartment 22. The thickness of the partition wall 21 is a value measured by microscopic observation of a cross-section parallel to the central axis.

[0045] then, Figure 5 This is a cross-sectional view of the exhaust gas treatment system 5 according to an embodiment of the present invention. The exhaust gas treatment system 5 includes the aforementioned honeycomb filter 1 arranged such that exhaust gas 5a passes through a compartment 22. The exhaust gas treatment system 5 can be installed in a vehicle equipped with an engine (internal combustion engine) for purifying exhaust gas 5a from the engine.

[0046] The honeycomb filter 1 and the exhaust gas treatment system 5 will be described in more detail below.

[0047] <About Cellular Filters>

[0048] In the honeycomb filter 1, such as Figure 2 As shown, the honeycomb structure 2 has a honeycomb shape with porous partitions 21, which divide the honeycomb structure into multiple compartments 22 that extend from the first end face 2a to the second end face 2b, forming a flow path for the fluid. The shape of the honeycomb filter 1 is not limited to... Figure 1 and Figure 2 The cylindrical shape shown can be categorized into elliptical cylindrical shapes, quadrilateral cylindrical shapes, and cylindrical shapes with polygonal bases, as well as cylindrical shapes with irregular base shapes.

[0049] Furthermore, the size of the honeycomb filter 1 is preferably such that its length along the central axis is 50 to 200 mm. Additionally, for example, if the honeycomb filter 1 is cylindrical, its bottom diameter is preferably 80 to 180 mm. If the honeycomb filter 1 is not cylindrical, its bottom area is preferably within the same range as the bottom area in the cylindrical case described above.

[0050] The cell density of the honeycomb filter 1 (i.e., the cell density of the cross section orthogonal to the central axis of the honeycomb structure 2) is preferably 7.7 to 46.5 cells / cm². 2 More preferably, 10–40 per cm 2 The preferred density is 15-25 per cm. 2 If less than 7.7 per cm 2 If the strength of the honeycomb filter 1 decreases, then the strength of the filter may also decrease. On the other hand, if it exceeds 46.5 cells / cm²... 2 If this happens, the pressure loss may increase.

[0051] The ratio of the length of the central axis of the honeycomb filter 1 to the diameter of the first end face 2a is preferably 0.5 to 1.5, more preferably 0.8 to 1.5, and particularly preferably 1.1 to 1.3. If it is less than 0.5, the length of the honeycomb structure portion 2 in the central axis direction becomes too short, thus reducing the filtration area and deteriorating the collection efficiency. In addition, the pressure loss may increase. On the other hand, if it exceeds 1.5, the length of the honeycomb structure portion 2 in the central axis direction becomes too long, thus increasing the pressure loss in the compartment flow path, and the overall pressure loss of the honeycomb filter 1 may become too large.

[0052] The average pore size of the partition wall 21 is preferably 7 to 40 μm, more preferably 8 to 35 μm. If it is less than 7 μm, the pressure loss may increase even when there is little accumulation of particulate matter. On the other hand, if it exceeds 40 μm, the honeycomb filter 1 may become brittle and easily detach, or the collection performance of particulate matter may decrease. The average pore size of the partition wall 21 is a value measured using a mercury porosimeter.

[0053] The shape of the compartments 22 in the honeycomb filter 1 is not particularly limited. In a cross-section orthogonal to the central axis, it is preferably a polygon, circle, or ellipse, such as a triangle, quadrilateral, pentagon, hexagon, or octagon, or other irregular shape. A combination of quadrilaterals and octagons is also preferred. Furthermore, in a cross-section orthogonal to the direction in which the compartments 22 extend, it is preferable that all compartments 22 have the same cross-sectional area. However, it is also preferable that the cross-sectional area of ​​the second compartment 222 with the sealing portion 3 on the first end face 2a side (the cross-sectional area in the cross-section orthogonal to the direction in which the compartments 22 extend) is smaller than the cross-sectional area of ​​the first compartment 221 with the sealing portion 3 on the second end face 2b side (the cross-sectional area in the cross-section orthogonal to the direction in which the compartments 22 extend). With such a configuration, the increase in pressure loss when capturing particulate matter in the exhaust gas 5a can be suppressed.

[0054] Furthermore, the hydraulic diameters of all compartments in the honeycomb structure 2 can be identical, and the hydraulic diameters of the first compartment 221 and the second compartment 222 can also be different, but it is preferable that the hydraulic diameters are different. Specifically, in the case of purifying the exhaust gas 5a of the gasoline engine, in order to reduce pressure loss, it is preferable that the hydraulic diameter of the second compartment 222 is larger than that of the first compartment 221, and the hydraulic diameter of the first compartment 221 is preferably 20% to 45% of the hydraulic diameter of the second compartment 222.

[0055] The outer peripheral wall 20 is preferably a molded integral wall formed integrally with the porous substrate during molding. However, a cement-coated wall in which the outer periphery of the porous substrate is ground to form a predetermined shape after molding and the outer peripheral wall 20 is formed from ceramic cement or the like is also a preferred form. In the case of a molded integral wall, the material of the outer peripheral wall 20 is preferably the same as the material of the honeycomb filter 1. In addition, when the outer peripheral wall 20 is a cement-coated wall, materials in which flux components such as glass are added to the matrix can be listed as materials for the cement-coated wall. Furthermore, the thickness of the outer peripheral wall 20 is preferably 0.5 to 1.5 mm.

[0056] A three-way catalyst can be supported in the honeycomb filter 1. A three-way catalyst is a catalyst that primarily purifies hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). Examples include catalysts containing platinum (Pt), palladium (Pd), and rhodium (Rh). With this three-way catalyst, hydrocarbons are purified into water and carbon dioxide through oxidation or reduction, carbon monoxide is purified into carbon dioxide through oxidation or reduction, and nitrogen oxides are purified into nitrogen through oxidation or reduction.

[0057] The catalyst loading per unit volume in the honeycomb filter 1 is preferably 160 g / L or less, more preferably 10 to 120 g / L, and particularly preferably 20 to 100 g / L. If the loading exceeds 160 g / L, the pores formed in the partition wall 21 will be blocked by the catalyst, and the pressure loss may become too large.

[0058] The sealing portion 3 disposed in the honeycomb filter 1 can be made of a sealing material containing ceramic raw material, water or alcohol, and organic binder. As the ceramic raw material, it is preferable to use the same ceramic raw material as the raw material used for the honeycomb structure portion 2 (the partition 21 of the honeycomb structure portion 2). Thus, during firing, the sealing portion 3 is firmly bonded to the partition 21.

[0059] The sealing section 3 is preferably configured such that the first compartment 221 and the second compartment 222 are alternately sealed so that the two end faces have a checkered pattern.

[0060] The depth of the sealing portion 3 is preferably 1 to 5 mm, more preferably 1 to 3 mm. If it is shallower than 1 mm, the strength of the sealing portion 3 may decrease. On the other hand, if it is deeper than 5 mm, the area of ​​PM capture by the partition wall 21 may become smaller. Here, the depth of the sealing portion 3 refers to the length of the sealing portion 3 in the direction in which the compartment 22 extends.

[0061] <About exhaust gas purification devices>

[0062] The honeycomb filter 1 can be housed in the tank 50. The honeycomb filter 1 can be disposed within the tank 50 with its outer periphery covered by a pad 51 (cushioning material). This pad 51 prevents the honeycomb filter 1 from breaking. Preferably, the honeycomb filter 1 is housed within the tank 50 with pressure applied from the outside through the pad 51. When housed in this state, movement of the honeycomb filter 1 within the tank 50 is prevented, ensuring its stability within the tank 50.

[0063] The canister 50 is not particularly limited and can be any canister commonly used for collecting and purifying ceramic honeycomb filters for automobile exhaust and other waste gases. Examples of materials for the canister 50 include ferritic stainless steel. The size of the canister 50 is preferably such that it can be pressed in while the gasket 51 is wound around the honeycomb filter 1. A canister with a length of approximately 100 to 300 mm is preferred for the canister 50. A ceramic fiber gasket or similar material can be used as the gasket 51.

[0064] <Regarding the manufacturing method of honeycomb filters>

[0065] A honeycomb body is obtained by extruding and shaping the clay into a honeycomb shape under the following conditions. One method for sealing the openings of the cells in the honeycomb body is to fill the openings with a sealing material. Specifically, a mask is applied to one end face of the honeycomb body to seal the openings of predetermined cells. The method of applying the mask is not particularly limited, but it is preferable to apply the mask in a manner that alternately seals the openings of predetermined cells on the first end face of the honeycomb body with the openings of the remaining cells on the second end face, resulting in a checkered pattern on both end faces. The sealing material, comprising a ceramic raw material, water or alcohol, and an organic binder, is stored in a storage container. The ceramic raw material is preferably the same as the raw material used for the honeycomb body. The ceramic raw material is preferably 70-90% by mass of the total sealing material. Water or alcohol is preferably 10-30% by mass of the total sealing material, and the organic binder is preferably 0.1-2.0% by mass of the total sealing material. Examples of organic adhesives include hydroxypropoxymethylcellulose and methylcellulose. Furthermore, the end of the component with the aforementioned mask applied is immersed in a storage container, and a sealing material is filled into the opening of the unmasked compartment to form a sealed portion. The viscosity of the sealing material is preferably 600–1200 Pa·s. Additionally, the viscosity of the sealing material is determined at a temperature of 30°C. o The value was measured using a rotational viscometer at 30 rpm. Then, a mask was applied to the other end face of the honeycomb structure to seal the openings of the remaining compartments. Next, the masked end face was immersed in a storage container containing a slurry-like sealing material, and the sealing material was filled into the openings of the unmasked compartments to form sealing portions. In this way, a honeycomb filter structure can be obtained in which the openings of predetermined compartments on one end face of the honeycomb structure and the openings of the remaining compartments on the other end face are equipped with sealing portions.

[0066] The firing temperature during the firing of the honeycomb filter molded body can be appropriately determined according to the material of the honeycomb filter molded body. For example, when the material of the honeycomb filter molded body is cordierite, the firing temperature is preferably 1380-1450℃. o C, more preferably 1400-1440 o C. In addition, the firing time is preferably set to 3 to 10 hours.

[0067] Alternatively, the honeycomb filter molded body can be dried before firing. The drying method is not particularly limited; examples include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze drying. Dielectric drying, microwave drying, or hot air drying are preferred, either alone or in combination. Furthermore, the drying conditions are preferably set at a drying temperature of 30–150°C.o C. Drying time: 1 minute to 2 hours.

[0068] Alternatively, the honeycomb molded body can be fired before the sealing portion is formed to obtain a fired honeycomb body. After the opening portion of the predetermined compartment in one end face and the opening portion of the remaining compartment in the other end face are sealed, the honeycomb filter is further fired to obtain a honeycomb filter.

[0069] Furthermore, a honeycomb filter can be obtained by coating a honeycomb filter structure with a catalyst slurry (supported catalyst) using a known method. For example, a catalyst slurry containing a ternary catalyst is first prepared. Then, the prepared catalyst slurry is flowed into the compartment by impregnation and suction. Preferably, the catalyst slurry is coated on the entire surface of the compartment wall. After the catalyst slurry flows into the compartment, excess slurry is blown away using compressed air. Then, by drying and baking the catalyst slurry, a sealed honeycomb structure with the catalyst supported on the surface of the compartment wall can be obtained. The drying conditions are preferably set to 80–150 °C. o C. 1–6 hours. Additionally, the preferred baking conditions are 450–700°C. o C. 0.5–6 hours. In addition, components other than the catalyst contained in the catalyst slurry can include alumina, etc.

[0070] <Regarding the assembly of the tank>

[0071] After covering the outer periphery of the honeycomb filter with a gasket (cushioning material), the honeycomb filter, covered by the gasket, is placed inside the tank. At this point, it is preferable that the honeycomb filter is housed in a compressed state within the tank. Examples of gaskets include ceramic fiber gaskets. This prevents the honeycomb filter from moving within the tank.

[0072] The tank body can use conventionally known tank bodies, for example, it can be manufactured by stamping and welding sheet material made of ferritic stainless steel. Specifically, the diameter of the inlet of the tank body is preferably 30 to 80 mm, and the diameter of the outlet is preferably 30 to 80 mm.

[0073] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to these examples. Various modifications and alterations will be readily apparent to anyone skilled in the art to which this invention pertains, within the scope of the technical concept set forth in the claims, and these are, of course, also understood to fall within the technical scope of this invention.

[0074]

Example

[0075] The present invention will be described in more detail below through embodiments. The present invention is not limited to these embodiments.

[0076] As shown in Tables 1 to 4 below, various honeycomb filters were fabricated, and the reduction rates of collection efficiency and pressure loss were investigated.

[0077] Table 1

[0078]

[0079] Table 2

[0080]

[0081] Table 3

[0082]

[0083] Table 4

[0084]

[0085] [About cellular filters]

[0086] In Comparative Examples 1 to Examples 1-4, the same honeycomb structure was used. Comparative Example 1 was an example without partially sealed compartments (an example in which no openings were provided in the sealing portions of all compartments). Examples 1-1 to 1-4 were examples with partially sealed compartments, with the number of partially sealed compartments and the area of ​​the openings in the sealing portions of the partially sealed compartments being varied. Similarly, the same honeycomb structure was used in the examples where the numbers immediately following the Comparative Examples and Examples were the same. In addition, the Comparative Examples were examples without partially sealed compartments, and the Examples were examples with partially sealed compartments. In the examples where the numbers immediately following the Examples contain consecutive branch numbers such as "-1", the number of partially sealed compartments and / or the area of ​​the openings in the sealing portions of the partially sealed compartments were varied.

[0087] In the examples where the numbers following the comparative examples and embodiments are "1" to "8", partially sealed compartments are provided only in some compartments. In the examples where the numbers following the comparative examples and embodiments are "9" and "10", partially sealed compartments are provided in both some compartments and normal compartments.

[0088] In Tables 1 to 4, “number of leaks” represents the number of incompletely sealed compartments.

[0089] "The perforation area ratio in a PCL" represents the ratio of the total area of ​​the openings in the partial compartments (incompletely sealed compartments) that have openings in the sealing section to the total area of ​​the partial compartments (incompletely sealed compartments) that have openings in the sealing section in the cross section of the cellular structure that is orthogonal to the direction in which the compartments extend (the opening area of ​​each partial compartment with openings in the sealing section).

[0090] "Void area ratio in all PCLs" represents the ratio of the total area of ​​the openings of the partially sealed compartments in all partial compartments to the total area of ​​all partial compartments in a cross section of the cellular structure orthogonal to the direction of compartment extension.

[0091] "The area ratio of the leaks in an NCL" refers to the ratio of the total area of ​​the openings in the normal compartments (incompletely sealed compartments) that have openings in the sealing section to the total area of ​​the normal compartments (incompletely sealed compartments) that have openings in the sealing section in the cross section of the cellular structure that is orthogonal to the direction in which the compartments extend.

[0092] "Porosity in the whole" refers to the ratio of the total area of ​​the openings in all the partially sealed compartments to the total area of ​​all the compartments in a cross section of the honeycomb structure orthogonal to the direction in which the compartments extend.

[0093] [Methods for investigating the rate of reduction in capture efficiency]

[0094] The reduction rate of soot collection efficiency is investigated as follows: An exhaust gas purification device is connected to the outlet side of the exhaust manifold of a 1.2L direct-injection gasoline engine vehicle, and the number of soot particles in the gas discharged from the outlet of the exhaust gas purification device is measured using the PN measurement method. The "PN measurement method" refers to the particulate matter measurement scheme (PMP) proposed by the Pollution and Energy Working Group (GRPE) of the World Forum for Harmonization of Vehicle Regulations (WP29) of the United Nations Economic Commission for Europe (ECE). Specifically, in determining the number of soot particles, the cumulative number of soot particles emitted after driving in WLTC (Worldwide Harmonized Light Duty Test Cycle) mode is used as the number of soot particles in the exhaust gas purification device to determine the collection efficiency. For the collection efficiency measured as described above, the difference between the collection efficiency of the honeycomb filter without incompletely sealed compartments (Comparative Example 1, etc.) and the collection efficiency of the incompletely sealed compartment honeycomb filter (honeycomb filter with incompletely sealed compartments) is calculated as the collection efficiency reduction rate.

[0095] [Methods for investigating pressure loss reduction rate]

[0096] The pressure loss reduction rate was investigated as follows: That is, the exhaust gas from the 1.2L direct injection gasoline engine was reduced to 700... o C, 600m 3 A flow rate of / h was introduced, and the pressures on the inflow and outflow sides of the honeycomb filter were measured. Furthermore, the pressure loss (kPa) of the honeycomb filter was determined by calculating the pressure difference between the inflow and outflow sides. For the pressure loss measured as described above, the ratio of the pressure loss of the incompletely sealed honeycomb filter to the pressure loss of a honeycomb filter without incompletely sealed compartments, such as Comparative Example 1, was calculated as the pressure loss reduction rate.

[0097] Figure 6 This is a graph showing the relationship between the percentage of the leakage area in the overall sample and the rate of reduction in capture efficiency in the embodiments and comparative examples. For example... Figure 6 As shown in the chart, the following trend is observed: the larger the perforated area ratio in the overall structure, the greater the rate of decrease in capture efficiency, i.e., the capture efficiency decreases, and the possibility of allowing particulate matter to pass through increases. If the perforated compartment is not partially sealed, but rather the sealing portion of the compartment is omitted, the perforated area ratio in the overall structure further increases. Although not listed as examples or comparative examples, based on... Figure 6 The results show that if the sealing portion of the compartment is omitted, the rate of decrease in collection efficiency further increases. That is, it can be seen that compared with omitting the sealing portion of the compartment, setting an incompletely sealed compartment as in the embodiment can suppress the passage of particulate matter.

[0098] On the other hand, by comparing the pressure loss reduction rate of each comparative example with the pressure loss reduction rate of each embodiment, it can be seen that, compared with the case of not setting an incompletely sealed compartment (comparative example), setting an incompletely sealed compartment (embodiment) can suppress the increase in pressure loss.

[0099] These results show that by setting up partially sealed compartments, it is possible to suppress the passage of particulate matter while also suppressing the increase in pressure loss.

[0100] In most embodiments, the reduction rate of trapping efficiency falls within the range of 0.0% to -1.0%, and the reduction rate of pressure loss is less than 0.0%. However, in embodiments 2-4, the reduction rate of trapping efficiency is -1.3%, and the passage of particulate matter relatively increases. Additionally, in embodiments 3-4 and 9-4, the reduction rate of pressure loss is 0.0%, which, while suppressing the increase in pressure loss, does not achieve a reduction in pressure loss. It is believed that the reduction rate of trapping efficiency of -1.3% in embodiments 2-4 is due to the relatively large orifice area ratio in one PCL, which is 91%. Conversely, it is believed that the reduction rate of pressure loss of 0.0% in embodiments 3-4 and 9-4 is due to the relatively small orifice area ratio in one PCL and / or one NCL, which is 2% to 4%. In embodiments where the reduction rate of trapping efficiency falls within the range of 0.0% to -1.0%, the orifice area ratio in one PCL and / or one NCL is 5% to 90%. According to the results, by making the ratio of the total area of ​​the openings in these partially sealed compartments to the total area of ​​the partially sealed compartments in the cross section of the honeycomb structure orthogonal to the direction of compartment extension 5% or more and 90% or less, it is possible to more reliably suppress the increase in pressure loss and more reliably suppress the passage of particulate matter.

[0101] The -1.3% reduction in capture efficiency in Examples 2-4 is considered to be due to the relatively large perforated area ratio of 1459 ppm. In the examples where the capture efficiency reduction rate falls between 0.0% and -1.0%, the perforated area ratio is 1400 ppm or less. Based on this result, it can be seen that by ensuring the ratio of the total area of ​​the openings in all incompletely sealed compartments to the total area of ​​all compartments in a cross-section orthogonal to the direction of compartment extension of the honeycomb structure is 1400 ppm or less, the passage of particulate matter can be more reliably suppressed.

[0102] Symbol Explanation

[0103] 1—Honeycomb filter; 2—Honeycomb structure; 2a—First end face; 2b—Second end face; 20—Outer peripheral wall; 21—Partial wall; 22—Compartment; 23—Normal compartment; 24—Partial compartment; 3—Sealing part; 3a—Opening; 4—Compartment; 5—Exhaust gas treatment system; 5a—Exhaust gas.

Claims

1. A honeycomb filter, characterized in that, have: A honeycomb structure having an outer peripheral wall and a partition wall, the partition wall being disposed on the inner side of the outer peripheral wall and dividing it into multiple compartments, the multiple compartments forming a flow path extending from a first end face to a second end face; and A sealing portion is disposed in the compartment on either the first end face or the second end face. The compartment includes at least one partially sealed compartment with an opening formed in the sealed portion, such that when light is shone onto either the first end face or the second end face, light leakage can be detected on the other end face.

2. The honeycomb filter according to claim 1, characterized in that, The total area of ​​the openings in the partially sealed compartments is 5% to 90% of the total area of ​​the partially sealed compartments in a cross section of the honeycomb structure orthogonal to the direction in which the compartments extend.

3. The honeycomb filter according to claim 2, characterized in that, The ratio of the total area of ​​the openings in all the partially sealed compartments to the total area of ​​all the compartments in a cross section of the honeycomb structure orthogonal to the direction in which the compartments extend is less than 1400 ppm.

4. The honeycomb filter according to any one of claims 1 to 3, characterized in that, The compartment includes a plurality of general compartments disposed away from the outer peripheral wall, and a plurality of partial compartments disposed adjacent to the outer peripheral wall and having a local cross-sectional shape relative to the plurality of general compartments. The at least one partially sealed compartment is disposed within the plurality of partial compartments.

5. The honeycomb filter according to any one of claims 1 to 3, characterized in that, The porosity of the partition wall is 45% or more and 70% or less, and the thickness of the partition wall is 127 μm or more and 254 μm or less.

6. A waste gas treatment system, characterized in that, A cellular filter comprising any one of claims 1 to 3, wherein the cellular filter is configured such that exhaust gas passes through the compartment.

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