JP6285194B2 - Honeycomb structure and exhaust gas purification device - Google Patents

Description

  The present invention relates to a honeycomb structure and an exhaust gas purification device. More specifically, the present invention relates to a honeycomb structure and an exhaust gas purification device that can measure the internal temperature with high accuracy and can easily exchange a temperature measurement probe such as a thermocouple.

  2. Description of the Related Art Conventionally, an exhaust gas purification apparatus including a honeycomb structure filter (honeycomb structure) has been used to remove particulates contained in exhaust gas discharged from various engines and the like to purify the exhaust gas. In this exhaust gas purifying apparatus, when exhaust gas containing fine particles is introduced from one end side of the filter, the fine particles are filtered by the partition walls of the filter, and the purified gas is discharged from the other end side of the filter. In this way, the exhaust gas purification device purifies the exhaust gas.

  In this exhaust gas purifying apparatus, a thermocouple is used behind the honeycomb structure in order to grasp the temperature inside the honeycomb structure, and the thermocouple is used to control the temperature of the gas discharged from the honeycomb structure. Measure (for example, see Patent Document 1).

JP-A-6-10654

  However, since the exhaust gas purifying apparatus described in Patent Document 1 measures the temperature of the gas discharged from the honeycomb structure, there is a possibility that an error occurs from the temperature inside the honeycomb structure. That is, since the temperature inside the honeycomb structure is not directly measured, there may be a deviation between the measured exhaust gas temperature and the original honeycomb structure temperature. Since such a shift has occurred, it is necessary to provide a margin for determining the catalyst deterioration. That is, if the catalyst is exposed to a predetermined temperature or more for a predetermined period or longer, the catalyst deteriorates and the catalyst function cannot be sufficiently obtained. For this reason, a criterion for catalyst degradation is set based on temperature information from the thermocouple, and the presence or absence of catalyst degradation is determined. This “catalyst degradation criterion” is set with a margin more than necessary because the temperature is deviated as described above.

  For this reason, it is possible to measure the temperature inside the honeycomb structure with high accuracy, and when the temperature measurement probe such as a thermocouple is damaged, the honeycomb structure can be easily replaced. And development of an exhaust gas purification device was eagerly desired.

  The present invention has been made in view of such problems of the prior art. An object of the present invention is to provide a honeycomb structure and an exhaust gas purifying apparatus that can directly measure the internal temperature and can easily replace a temperature measuring probe such as a thermocouple.

  According to the present invention, the following honeycomb structure and exhaust gas purification device are provided.

[1] A honeycomb base having a porous partition wall that defines a plurality of cells that serve as a fluid flow path and extend from an inflow end surface that is one end surface into which the fluid flows in to an outflow end surface that is the other end surface from which the fluid flows out And a plugging portion disposed in the opening portion on the outflow end face side of the inlet cell that is a predetermined cell of the honeycomb base material and the opening portion on the inflow end face of the outlet cell that is a remaining cell. And at least one groove for inserting a temperature measurement probe having an opening on a side surface of the honeycomb substrate, and the opening of the groove in the circumferential direction of the honeycomb substrate. length is 0.5 to 20 mm, before Symbol said honeycomb structure being formed so as not to penetrate the septum of the outer peripheral portion of the honeycomb substrate.

[2] The honeycomb substrate includes a plurality of honeycomb segments and a bonding layer that bonds the plurality of honeycomb segments to each other, and the groove is formed only in the bonding layer of the honeycomb substrate. The honeycomb structure according to 1].

[ 3 ] The honeycomb structure according to [1] or [2] , wherein the groove has a depth of 1 mm or more.

[ 4 ] The honeycomb structure according to any one of [1] to [ 3 ], wherein a length of the opening of the groove in a cell extending direction of the honeycomb base is 0.5 mm or more.

[ 5 ] The honeycomb structure according to any one of [1] to [ 4 ], an inlet into which exhaust gas flows, an outlet from which purified exhaust gas flows out, and between the inlet and the outlet A can body that houses the honeycomb structure in the body portion, and the can body is formed on the honeycomb base material of the honeycomb structure in the body portion. At least one through hole having an opening having an area larger than the area of the opening of the groove is formed, and the honeycomb structure has the groove formed in the honeycomb substrate and the through hole of the can body. A temperature measurement that is disposed in a communicating position, passes through the through-hole of the can body, and is inserted into the groove portion of the honeycomb base material of the honeycomb structure to measure the temperature of exhaust gas inside the honeycomb structure. Exhaust purification equipment equipped with a probe .

  In the honeycomb structure of the present invention, a groove portion is formed in the honeycomb base material, and a temperature measuring probe such as a thermocouple can be inserted into the groove portion and disposed inside the honeycomb structure, so that the temperature inside the honeycomb structure can be directly measured. . As a result, the temperature inside the honeycomb structure can be measured with high accuracy. In addition, the honeycomb structure of the present invention can be easily replaced because the temperature measurement probe inserted into the groove is extracted and then a new temperature measurement probe is inserted into the groove.

  In the exhaust gas purifying apparatus of the present invention, a groove is formed in the honeycomb base material of the honeycomb structure, and a measurement probe can be inserted into the groove and disposed inside the honeycomb structure, so that the temperature inside the honeycomb structure can be directly measured. As a result, the temperature inside the honeycomb structure can be measured with high accuracy. Further, the exhaust gas purifying apparatus of the present invention extracts the temperature measuring probe inserted into the through hole of the can body and the groove portion of the honeycomb base material of the honeycomb structure, and then inserts the new temperature measuring probe into the through hole of the can body. Therefore, the probe for temperature measurement can be easily replaced because it can be inserted into the groove of the honeycomb substrate of the honeycomb structure.

1 is a perspective view schematically showing an embodiment of a honeycomb structure of the present invention. It is a perspective view which shows typically other embodiment of the honeycomb structure of this invention. 1 is a cross-sectional view schematically showing a cross section parallel to a cell extending direction of a honeycomb structure in an embodiment of an exhaust gas purification apparatus of the present invention. It is a schematic diagram which shows the arrangement | sequence of the engine, DOC, and exhaust gas purification apparatus in a temperature measurement test. It is a graph which shows the measurement conditions (time, engine torque, engine speed) in a temperature measurement test. [Fig. 3] Fig. 3 is a plan view schematically showing a temperature measurement position in a temperature measurement test as seen from one end face side of the honeycomb structure. It is sectional drawing which shows typically the A-A 'cross section shown to FIG. 6A. It is sectional drawing which shows typically the B-B 'cross section shown to FIG. 6A.

  Embodiments of the present invention will be described below. The present invention is not limited to the following embodiments, and appropriate modifications and improvements are added to the following embodiments on the basis of ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that what has been described also falls within the scope of the invention.

[1] Honeycomb structure:
One embodiment of the honeycomb structure of the present invention is a honeycomb structure 100 shown in FIG. The honeycomb structure 100 is a porous partition wall that forms a plurality of cells 2 that extend from an inflow end surface 11 that is one end surface into which a fluid flows in to the outflow end surface 12 that flows out of the fluid. 1 is provided. Furthermore, the honeycomb structure 100 includes a plugging portion 25 disposed at one end of a predetermined cell of the cells 2 and the other end of the remaining cells. In the honeycomb structure 100, at least one groove 20 for inserting a temperature measurement probe having an opening on the side surface of the honeycomb substrate 10 is formed. And the length of the opening part of the groove part 20 in the circumferential direction of the honeycomb base material 10 (namely, the length of the opening part of the groove part 20 in the circumferential direction of the honeycomb base material 10) is 0.5 to 20 mm. The groove 20 is formed so as not to penetrate the partition wall 1 of the outer peripheral portion of the honeycomb base material 10.

  Specifically, the temperature inside the honeycomb structure is not uniform in the axial direction of the honeycomb structure (that is, the direction in which the cells of the honeycomb structure extend) and in the radial direction. In addition, the honeycomb structure is actually heated at a part of the inside of the honeycomb structure. For this reason, it is difficult to accurately grasp the temperature inside the honeycomb structure with a thermocouple arranged several tens of millimeters downstream of the honeycomb structure (that is, outside the honeycomb structure). There is a problem that a large error occurs between the temperature of the structure and the structure. As described above, there is a case where a deviation occurs between the temperature of the exhaust gas to be measured and the original temperature of the honeycomb structure. Therefore, it is necessary to provide a margin for the determination of catalyst deterioration. That is, if the catalyst is exposed to a predetermined temperature or more for a predetermined period or longer, the catalyst deteriorates and the catalyst function cannot be sufficiently obtained. For this reason, a catalyst deterioration standard is set based on temperature information from a temperature measurement probe such as a thermocouple (hereinafter sometimes simply referred to as “measurement probe”) to determine the presence or absence of catalyst deterioration. . This “catalyst degradation criterion” is set with a margin more than necessary because the temperature is deviated as described above. Thus, it is necessary to estimate a large amount of the catalyst to be supported in consideration of the temperature error. That is, the catalyst may be wasted. On the other hand, in the honeycomb structure 100, the groove portion 20 is formed in the honeycomb substrate 10, and a thermocouple (measurement probe) 30 (see FIG. 3) is inserted into the groove portion 20 to directly measure the temperature inside the honeycomb structure 100. doing. Therefore, the above problems do not occur, and the temperature inside the honeycomb structure 100 can be measured with high accuracy. Moreover, it is possible to prevent the catalyst from being wasted.

  In addition, the honeycomb structure 100 can be easily replaced because the thermocouple 30 inserted into the groove portion 20 is extracted and then a new thermocouple 30 is inserted into the groove portion 20. For example, it is easy to repair a thermocouple when it fails.

  Furthermore, even in the conventional technique, it is possible to insert a measurement probe into the honeycomb structure. In this case, the measurement probe is inserted from the exit end face side. However, when the measurement probe is inserted, the measurement probe may come into contact with the partition wall and the partition wall may be damaged. In addition, since the measurement probe is inserted along the cell which is the exhaust gas flow path, there is a problem that the flow path resistance is increased, resulting in an increase in pressure loss. Further, since the measurement probe is inserted into the cell as described above, a long measurement probe is required, resulting in an increase in cost. Further, when the measurement probe becomes longer, the influence of the flow of exhaust gas becomes larger. Specifically, the measurement probe moves in the cell due to the exhaust gas, and the honeycomb structure (partition wall) is damaged. Furthermore, the measurement probe needs to be inserted into a specific cell. In this case, the measurement probe needs to be inserted after dismantling the converter. Therefore, cost and work time will be required.

  FIG. 1 is a perspective view schematically showing one embodiment of a honeycomb structure of the present invention.

[1-1] Honeycomb substrate:
As described above, at least one groove 20 for inserting a measurement probe is formed in the honeycomb base material 10. The groove 20 has an opening having a length in the circumferential direction of the honeycomb substrate 10 of 0.5 to 20 mm. The “groove” is a hole for inserting a measurement probe for measuring the temperature inside the honeycomb structure, and more specifically, a hole that fits into the measurement probe (particularly the tip of the sensor of the measurement probe). That is.

  The shape of the opening of the groove is not particularly limited as long as the measurement probe can be inserted. That is, it can be appropriately set according to the shape of the measurement probe (in particular, the tip of the sensor of the measurement probe). Examples of the shape of the opening of the groove include a circle, an ellipse, a square, and a rectangle. In addition, when the shape of the opening is a rectangle, the groove can also be referred to as a “slit”. The groove 20 shown in FIG. 1 has a rectangular opening, and can also be referred to as a “slit”.

  The length of the opening of the groove in the circumferential direction of the honeycomb base material (hereinafter sometimes referred to as “the width of the groove”) is preferably 0.5 to 10 mm, preferably 0.5 to 3.0 mm. More preferably, it is particularly preferably 0.5 to 1.0 mm. If the width of the groove is less than the lower limit, the measurement probe may not be inserted. If the groove width exceeds the above upper limit, when a measurement probe such as a thermocouple is inserted into the groove, the pressure loss increases excessively due to the presence of the measurement probe, causing a decrease in engine output. There is a fear. “The length in the circumferential direction of the honeycomb base material of the opening of the groove part” means that when “a plurality of the lengths of the opening part of the groove part in the circumferential direction of the honeycomb base material” are obtained in one groove part, The maximum length of the “length of the opening in the circumferential direction of the honeycomb base material” is referred to. “When a plurality of grooves are obtained in one groove” means that the “length of the opening in the groove in the circumferential direction of the honeycomb substrate” is not uniform even in one groove. The “width of the groove” is indicated by the symbol “H” in FIG.

  The lower limit of the length of the opening of the groove in the direction in which the cells of the honeycomb substrate extend (hereinafter may be referred to as “the length of the groove”) is preferably 0.5 mm. The upper limit of the length of the groove is preferably 50% of the total length of the honeycomb base material, more preferably 30% of the total length of the honeycomb base material, and 15% of the total length of the honeycomb base material. It is particularly preferred. If the length of the groove is less than the lower limit, a measurement probe such as a thermocouple may not be inserted. If the length of the groove part exceeds the upper limit, the shear stress resistance in the full length direction of the honeycomb base material may be deteriorated. “The length of the opening of the groove part in the extending direction of the cells of the honeycomb base material” means that “the length of the opening of the groove part of the cell of the honeycomb base cell in the extending direction” is obtained in one groove part. The maximum length of “the length of the opening of the groove in the cell extending direction of the honeycomb substrate”. “When a plurality of grooves are obtained in one groove” means that the “length of the opening of the groove in the cell extending direction of the honeycomb substrate” is not uniform even in one groove. “The length of the groove” is indicated by the symbol “L” in FIG.

  The depth of the groove is preferably 1 mm or more. If the depth of the groove is less than 1 mm, the temperature inside the honeycomb substrate may not be accurately estimated. Note that when a plurality of “groove depths” are obtained in one groove portion, that is, when the depth is not uniform even in one groove portion, the depth at the position where the distance from the opening of the groove portion is farthest. Say. The “depth of the groove” is indicated by a symbol “D” in FIG.

  The depth of the groove is 1 mm or more, and the ratio of the depth of the groove to the distance from the outer periphery to the area centroid ([depth of the groove / distance from the outer periphery to the area centroid] × 100) is 10% or more. It is preferable to satisfy that. By doing in this way, measurement accuracy can be made higher. The “area center of gravity” is the center of gravity of the figure drawn by the outer peripheral edge of the honeycomb structure in a cross section orthogonal to the cell extending direction of the honeycomb structure. The “distance from the outer periphery to the area centroid” means the shortest straight line drawn from the “area centroid” to the “outer periphery of the honeycomb substrate” in the cross section. That is, when the honeycomb structure is cylindrical, the “distance from the outer periphery to the area center of gravity” is the radius of the honeycomb structure in a cross section orthogonal to the cell extending direction of the honeycomb structure.

  Further, the depth of the groove is 1 mm or more, and the ratio of the depth of the groove to the distance from the outer periphery to the area center of gravity ([depth of the groove / distance from the outer periphery to the area center of gravity] × 100) is 25% or more. It is preferable to satisfy that. In this way, the measurement accuracy can be further increased.

  In addition, it is preferable that the depth of the groove is deeper, and it is preferable that the groove extends to the center in the cross section orthogonal to the cell extending direction of the honeycomb structure. Specifically, the “central part” refers to the center of gravity of the area.

  It is preferable that 1 to 5 grooves are formed, more preferably 1 to 4 grooves are formed, and particularly preferably 1 to 3 grooves are formed. By forming a plurality of grooves, the temperature of the exhaust gas inside the honeycomb structure can be measured more accurately.

  When a plurality of groove portions are formed, each groove portion may have the same shape or may be different.

  The position for forming the groove is not particularly limited. For example, when the honeycomb substrate has a plurality of honeycomb segments and a bonding layer for bonding the plurality of honeycomb segments to each other (a honeycomb substrate having a segment structure), a groove portion is formed in the bonding layer of the honeycomb substrate (that is, only the bonding layer). Can be formed. Moreover, you may form a groove part in parts other than a joining layer. That is, the groove portion may be formed so as to penetrate the partition wall on the outer peripheral portion of the honeycomb base material. In the honeycomb substrate having the segment structure, the groove portion can be formed in either or both of the bonding layer and the portion other than the bonding layer. On the other hand, in the honeycomb structure (honeycomb base material) integrally formed by extrusion molding or the like as in the honeycomb structure 100 shown in FIG. 2, since the bonding layer does not exist, the groove portion is the outer peripheral portion of the honeycomb base material. It is formed so as to penetrate the partition wall. In the present specification, the “honeycomb segment” may be referred to as a “honeycomb segment fired body”.

  In the case of “a honeycomb substrate having a segment structure”, it is preferable that the groove is formed in the bonding layer of the honeycomb substrate. That is, in the case of the “segment-structured honeycomb substrate”, the position where the groove is formed is preferably the bonding layer of the honeycomb substrate. When the groove is formed in this way, it is possible to prevent the exhaust gas flowing in the cell from leaking outside through the groove. In addition, it is possible to prevent the flow of exhaust gas from deteriorating and increasing pressure loss due to the arrangement of a measurement probe (hereinafter sometimes referred to as “thermocouple”) in the cell.

  In the case of the “segmented honeycomb substrate”, it is preferable that all of the groove portions are formed in the bonding layer of the honeycomb substrate. By doing in this way, it can prevent still more favorably that the said waste gas will leak outside through a groove part, and pressure loss will increase.

  A honeycomb structure 100 shown in FIG. 1 includes a plurality of honeycomb segments 22 and a bonding layer 24 that bonds the plurality of honeycomb segments 22 to each other. In the honeycomb structure 100, all the three groove portions 20 are formed in the bonding layer 24 of the honeycomb substrate 10. All of the three groove portions 20 have different positions in the extending direction of the cells 2 of the honeycomb base material 10 in one bonding layer 24 extending from the inflow end surface of the honeycomb structure 100 to the outflow end surface 12 on the side surface of the honeycomb structure 100. Is formed. The shape of the opening of the groove 20 of the honeycomb structure 100 is a rectangle that is long in the extending direction of the cells 2 of the honeycomb structure 100.

  Further, the honeycomb structure 101 shown in FIG. 2 is integrally formed by extrusion molding or the like, and the honeycomb structure 101 has the groove portion 20 penetrating the partition wall 1 in the outer peripheral portion of the honeycomb base material 10. Is formed. When the groove portion 20 is formed so as to penetrate the partition wall on the outer peripheral portion of the honeycomb base material 10 as in the honeycomb structure 101, after the measurement probe is inserted into the groove portion 20, the opening portion of the groove portion is made of a cement material or the like. It is preferable to close with. This is to prevent the exhaust gas from leaking from the opening of the groove. Examples of the cement material include materials composed of inorganic fibers, inorganic binders, organic binders, inorganic particles, and foamed resins. Specifically, examples of the inorganic fiber include oxide fibers such as aluminosilicate and alumina, and other fibers (for example, SiC fibers). Examples of the inorganic binder include silica sol, alumina sol, clay and the like. Examples of the organic binder include polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), methyl cellulose (MC), and the like. Examples of the inorganic particles include ceramics such as silicon carbide, silicon nitride, cordierite, alumina, and mullite. In addition to such a cement material, the opening portion of the groove portion (opening portion of the groove portion after insertion of the thermocouple) may be closed by the outer periphery coating material constituting the outer periphery coating layer. FIG. 2 is a perspective view schematically showing another embodiment of the honeycomb structure of the present invention.

  The formation position of the groove portion in the cell extending direction of the honeycomb base material (formation position in the length direction) is such that the distance from the inlet end surface is within a range of 5 to 95% of the length of the honeycomb base material cell extension direction. It is preferable that Further, the “formation position in the length direction” is more preferably in the range of 10 to 90% of the length in the cell extending direction of the honeycomb base material, and the distance from the inlet end surface is 10 to 50%. It is particularly preferable that the value falls within the range. If the “formation position in the length direction” exceeds the upper limit, the measurement accuracy may not be sufficiently improved.

  When a plurality of groove portions are formed, the arrangement of the groove portions can be determined as appropriate, but for example, the groove portions are preferably arranged as follows. The first groove is arranged at the end on the inlet end face side, and the second groove is arranged in the center (in the middle of the inlet end face and the outlet end face) in the cell extending direction of the honeycomb substrate. By arranging the grooves in this way, the temperature in a region where the temperature estimation accuracy is not sufficient in the conventional method (specifically, the region from the inlet end surface to the central portion) can be accurately estimated.

  In addition to the temperature measurement probe, a sensor that can detect the type and concentration of a specific gas can be inserted into the groove.

  The thickness of the partition walls of the honeycomb substrate 10 is preferably 120 to 500 μm, more preferably 200 to 450 μm, and particularly preferably 250 to 400 μm. If the partition wall thickness is less than 120 μm, the partition wall strength may be insufficient. On the other hand, if it exceeds 500 μm, the pressure loss may increase.

  The porosity of the partition walls of the honeycomb base material 10 is preferably 30 to 75%, more preferably 35 to 70%, and particularly preferably 40 to 65%. If the porosity is less than 30%, pressure loss may increase. On the other hand, if it exceeds 75%, the strength of the partition may be lowered. Here, in this specification, “porosity” is a value measured with a mercury porosimeter.

  The average pore diameter of the partition walls of the honeycomb substrate 10 is preferably 5 to 35 μm, more preferably 8 to 30 μm, and particularly preferably 10 to 25 μm. There exists a possibility that a pressure loss may increase that the said average pore diameter is less than 5 micrometers. On the other hand, if it exceeds 35 μm, the exhaust gas purification performance may be reduced. Here, the “average pore diameter” in the present specification is a value measured with a mercury porosimeter.

The cell density of the honeycomb base material 10 is preferably from 15 to 70 cells / cm ^2, further preferably 30 to 65 cells / cm ^2, and particularly preferably 38 to 55 cells / cm ^2. If the cell density is less than 15 cells / cm ² , the pressure loss after soot deposition may increase. On the other hand, if it exceeds 70 cells / cm ² , the pressure loss may increase.

  As a material for the partition wall, a ceramic material is preferable. From the viewpoint of excellent strength and heat resistance, selected from the group consisting of cordierite, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, aluminum titanate, silicon nitride, and silicon carbide-cordierite based composite material More preferred is at least one selected from the group consisting of Among these, cordierite is preferable.

  The shape of the cell 2 in the cross section orthogonal to the extending direction of the cell 2 of the honeycomb base material 10 can be a square shape, a hexagonal shape, or the like.

  The length in the cell extending direction of the honeycomb substrate 10 (honeycomb structure 100) can be set to 50 to 400 mm. Moreover, when the end surface of the honeycomb structure 100 is circular, the diameter of the end surface can be set to 100 to 400 mm.

  The shape of the honeycomb substrate 10 may be a columnar shape, an elliptical column shape, a quadrangular column shape, a hexagonal column shape, or the like. Among these, a cylindrical shape and a quadrangular prism shape are preferable.

  The honeycomb substrate may be a bonded body having a plurality of honeycomb segments and a bonding layer that bonds the plurality of honeycomb segments to each other. In this case, as described above, the groove is preferably formed in the bonding layer.

[1-2] Plugging portion:
The honeycomb structure 100 is arranged in an opening on the outflow end face 12 side of an inlet cell that is a predetermined cell 2 of the honeycomb substrate 10 and an opening on an inflow end face 11 of an outlet cell that is a remaining cell 2. The sealing part 25 is provided.

  The arrangement state of the plugged portion is not particularly limited as long as the plugged portion is formed so as to plug the cell at either the inflow end surface side or the outflow end surface side. For example, the plugging portion 25 is preferably arranged so that the inlet cells and the outlet cells are alternately arranged.

  The depth of the plugged portion (the length in the cell extending direction) is preferably 1 to 20 mm, more preferably 2 to 15 mm, and particularly preferably 3 to 10 mm.

  The material of the plugging portion can be the same as that of the partition wall.

  The honeycomb structure 100 shown in FIG. 1 has the outer peripheral coat layer 26, but may not have the outer peripheral coat layer 26. The outer peripheral coat layer 26 can be formed by applying a ceramic material to the outer periphery of the honeycomb structure. Further, when the honeycomb structure is integrally formed by extrusion molding or the like, the outer peripheral coat layer 26 may be formed together with partition walls in the process of manufacturing the honeycomb substrate 10.

[1-3] Catalyst:
In the honeycomb structure of the present invention, a catalyst may be supported on the surfaces of the partition walls of the honeycomb base material or the inner surfaces of the pores of the partition walls.

Examples of the catalyst include a three-way catalyst, a NO _X storage reduction catalyst, an oxidation catalyst, and a NO _X selective reduction catalyst. In addition to the catalyst described above, it is possible to appropriately select an appropriate catalyst type for the oxidation of harmful components and soot in exhaust gas and the purification of NOx.

[2] Exhaust gas purification device:
One embodiment of the exhaust gas purifying apparatus of the present invention is an exhaust gas purifying apparatus 200 shown in FIG. The exhaust gas purification apparatus 200 includes the above-described honeycomb structure 100 and a can body 150 that houses the honeycomb structure 100. The can body 150 includes an inlet 51 through which exhaust gas flows, an outlet 52 through which purified exhaust gas flows out, and a trunk portion 53 positioned between the inlet 51 and the outlet 52. The structure 100 is accommodated. The can body 150 has at least one through-hole 55 having an opening of “an area larger than the area of the opening of the groove 20 formed in the honeycomb substrate 10 of the honeycomb structure 100”. The honeycomb structure 100 is disposed at a position where the groove 20 formed in the honeycomb substrate 10 and the through hole 55 of the can body 150 communicate with each other. The exhaust gas purifying apparatus 200 passes through the through hole 55 of the can body 150, is inserted into the groove portion 20 of the honeycomb base material 10 of the honeycomb structure 100, and is disposed inside the honeycomb structure 100, and the temperature of the exhaust gas inside the honeycomb structure 100 A thermocouple (measuring probe) 30 is provided. Fig. 3 is a cross-sectional view schematically showing a cross section parallel to the cell extending direction of the honeycomb structure in one embodiment of the exhaust gas purifying apparatus of the present invention. FIG. 3 shows a state where one of the three thermocouples is removed.

  In such an exhaust gas purifying apparatus 200, a groove portion 20 is formed in the honeycomb substrate 10 of the honeycomb structure 100, and a thermocouple (measurement probe) 30 is inserted into the groove portion 20 to directly control the temperature inside the honeycomb structure 100. Measuring. Therefore, the temperature inside the honeycomb structure 100 can be measured with high accuracy. Moreover, since the exhaust gas purification apparatus 200 can replace the thermocouple (measurement probe) 30 by the following operation, the measurement probe can be easily replaced. That is, the through hole 55 of the can body 150 and the thermocouple 30 inserted in the groove portion 20 of the honeycomb base material 10 of the honeycomb structure 100 are extracted, and then the new thermocouple 30 is replaced with the through hole 55 of the can body 150 and the honeycomb structure. What is necessary is just to insert in the groove part 20 of the honeycomb base material 10 of the body 100. FIG. As described above, the exhaust gas purifying apparatus 200 can easily exchange a measurement probe such as a thermocouple.

  “A through-hole having an opening having an area larger than the area of the opening of the groove” means that the through-hole has the following opening. That is, when the position of the can body and the honeycomb structure is adjusted and the groove portion and the through hole of the can body are communicated with each other, the area of the opening portion of the through hole is too small so that a part of the groove portion is the body of the can body. This means that the through hole has an opening having an area that is not covered by the portion. That is, it is possible to prevent the groove portion from being covered by the body portion of the can body.

[2-1] Can body:
As described above, the can body is formed with at least one through hole having an opening having an area larger than the area of the opening of the groove formed in the honeycomb base material of the honeycomb structure.

  The through holes of the can body are preferably formed in the same shape, the same number, and the same arrangement as the openings of the groove portions formed in the honeycomb substrate (see FIG. 3).

  In the exhaust gas purifying apparatus of the present invention, the honeycomb structure is stored in a fixed state in the can while being held by a holding material arranged so as to cover the outer peripheral surface thereof.

  The can body 150 of the exhaust gas purifying apparatus 200 further includes an expanded tube portion 56 whose diameter gradually increases from the inlet 51 to the trunk portion 53 and a narrow tube portion 57 whose diameter gradually decreases from the trunk portion 53 to the outlet 52. .

  For example, the material of the can body 150 is preferably made of stainless steel, and particularly preferably made of chromium-based or chromium-nickel-based stainless steel.

[2-2] Measurement probe:
The measurement probe is not particularly limited as long as the sensor portion is large enough to be inserted into the groove portion of the honeycomb structure, and a conventionally known measurement probe can be used. Examples of the measurement probe include a temperature measurement probe. Examples of the temperature measuring probe include a thermocouple and a thermistor. Examples of the thermocouple include a K thermocouple, a J thermocouple, a T thermocouple, an E thermocouple, an N thermocouple, and an R thermocouple. A sensor having a diameter of 0.5 mm or the like can be used as a sensor (a part inserted into the groove) of these thermocouples or thermistors.

[3] Manufacturing method of honeycomb structure:
The honeycomb structure of the present invention can be manufactured as follows, for example. A segmented honeycomb structure will be described.

  First, a kneaded material for preparing a honeycomb base material is prepared, and this kneaded material is formed to prepare a honeycomb segment formed body (forming step).

  Next, the obtained honeycomb segment formed body (or the dried honeycomb segment dried body as necessary) is fired to produce a plurality of honeycomb segment fired bodies (honeycomb segment fired body producing step).

  Next, a plurality of honeycomb segment fired bodies are joined with a joining material to produce a honeycomb segment joined body (joining step). In this joining step, when the honeycomb segment fired bodies are joined with the joining material, a jig having a shape corresponding to the groove (a jig complementary to the groove) is disposed so as to be sandwiched between the honeycomb segment fired bodies. In this way, the bonding material is not applied to the portion where the jig is disposed. Then, when the honeycomb segment bonded body is obtained, the groove portion can be formed by removing the jig. That is, by embedding the jig in the bonding material, a groove portion forming a desired space can be easily formed.

  The “jig having a shape corresponding to the groove” is not particularly limited as long as a desired space can be obtained when the jig is removed. For example, a metal rod made of aluminum or the like can be used.

  In addition, a groove part can also be formed by cutting other than the method of forming using the said jig | tool.

  Next, plugging portions are formed by plugging the opening portions of the inlet cells that are predetermined cells on the inflow end surface of the joined honeycomb segment assembly and the opening portions of the outlet cells that are remaining cells on the outflow end surface. (Plugging process). In this way, a honeycomb structure in which the honeycomb substrate has a segment structure can be manufactured.

[4] Manufacturing method of exhaust gas purification device:
The exhaust gas purification apparatus of the present invention can be manufactured, for example, as follows.

  First, a honeycomb structure is manufactured as described above. Next, the outer peripheral surface of the manufactured honeycomb structure is wrapped with a holding material such as a ceramic fiber mat and pressed into the body of the can body. In the can body, the through hole is formed in the body portion as described above, and when the honeycomb structure is press-fitted into the can body, the groove portion formed in the honeycomb substrate and the through hole of the can body communicate with each other. The honeycomb structure is adjusted and arranged as described above. Next, the tip of the thermocouple sensor is passed through the through hole of the can body and inserted into the groove of the honeycomb substrate of the honeycomb structure. In this way, the exhaust gas purification apparatus of the present invention can be produced.

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

Example 1
Silicon carbide (SiC) powder and metal silicon (Si) powder were mixed at a mass ratio of 80:20 to obtain a ceramic raw material. To the obtained ceramic raw material, hydroxypropylmethylcellulose as a binder and a water-absorbing resin as a pore former were added, and water was added as a forming raw material, and the forming raw material was kneaded with a vacuum kneader to prepare a clay. . The binder content is 7 parts by mass when the total of silicon carbide (SiC) powder and metal silicon (Si) powder is 100 parts by mass, and the pore former content is silicon carbide (SiC) powder and metal silicon. When the total amount of (Si) powder is 100 parts by mass, the content of water is 42 parts by mass when the total of silicon carbide (SiC) powder and metal silicon (Si) powder is 100 parts by mass. Was part.

  Next, the obtained kneaded material was molded using an extrusion molding machine to obtain a honeycomb molded body. The obtained honeycomb formed body was dried by high-frequency dielectric heating and then dried at 120 ° C. for 2 hours using a hot air dryer, and both end surfaces were cut by a predetermined amount. Next, the dried honeycomb formed body was degreased and fired to obtain a honeycomb fired body. The degreasing conditions were 550 ° C. for 3 hours. The firing conditions were 1450 ° C. and 2 hours in an argon atmosphere. In this way, a honeycomb segment fired body was obtained. Then, 16 such honeycomb segment fired bodies were produced.

  All of the obtained honeycomb segment fired bodies had a square shape with a cross section perpendicular to the cell extending direction of 36 mm on a side, and the length in the cell extending direction was 152 mm.

  Next, with respect to the obtained 16 honeycomb segment fired bodies, the respective side surfaces are bonded with a bonding material (4 vertical × 4 horizontal), dried, and the cross-sectional shape orthogonal to the central axis is square. A joined honeycomb segment assembly (a rectangular column shaped honeycomb segment assembly) was obtained. As the bonding material, a material obtained by further mixing an inorganic binder, a dispersant, and water with a mixture of an organic binder and a foamed resin, and kneading with a mixer for 30 minutes was used.

  When the honeycomb segment fired bodies were joined with the joining material, a plate-shaped jig corresponding to the groove (a jig complementary to the groove) was disposed between the honeycomb segment fired bodies. Specifically, one jig made of aluminum having a length of 1 mm, a width of 1 mm, and a length of 100 mm was used as the jig. The jig is disposed at a position where the distance from the inflow end surface of the honeycomb segment fired body to the jig is 76 mm, and the length of the portion sandwiched between the honeycomb segment fired bodies (that is, the length corresponding to the “depth of the groove”) ) Was 54 mm. In this way, the bonding material was not applied to the portion where the jig was placed. Thereafter, when the bonded honeycomb segment assembly was obtained, the jig was removed to form a groove. By embedding the jig in the bonding material, a groove portion forming a desired space could be easily formed.

  Next, the outer peripheral portion of the obtained rectangular columnar honeycomb segment bonded body was cut to obtain a cylindrical honeycomb segment bonded body. Thereafter, an outer peripheral coating material was applied to the outer peripheral portion of the cylindrical honeycomb segment bonded body to form an outer peripheral coating layer.

  Next, with respect to the obtained cylindrical honeycomb segment bonded body, a plugged portion was formed at one end portion of a predetermined cell and the other end portion of the remaining cells to obtain a honeycomb structure. Note that the predetermined cells and the remaining cells are arranged alternately (alternately). As a result, a checkered pattern is formed on both end faces by the opening and plugging portion of the cell. As the plugging filler, the same raw material as that for the honeycomb segment fired body was used.

  Next, with respect to the obtained honeycomb structure, a thermocouple (K thermocouple, diameter 0.5 mm) was inserted into the cell from the outlet end face and arranged. The temperature measurement positions measured by this thermocouple were “TC-01”, “TC-02”, and “TC-03” shown in FIGS. 6A and 6B. Specifically, “TC-01”, “TC-02”, and “TC-03” are determined as follows. That is, in the cross section perpendicular to the cell extending direction of the honeycomb structure, assuming that the central axis of the honeycomb structure is the origin O (see FIG. 6A) and the X axis and the Y axis are assumed, 18 mm in the X axis direction from the origin, The position was 18 mm in the Y-axis direction. Furthermore, “TC-01” is a position at a distance of 15 mm from the inflow end face. “TC-02” is a position where the distance from the inflow end face is 76 mm. “TC-03” is a position at a distance of 137 mm from the inflow end face. Note that “TC-01”, “TC-02”, and “TC-03” are measurement target portions where the temperature inside the honeycomb structure should be measured. That is, it can be considered that the temperature inside the honeycomb structure can be measured with higher accuracy as the difference between the temperature measured at the measurement target portion and the estimated source temperature described later is smaller. FIG. 6A is a plan view schematically showing a temperature measurement position in a temperature measurement test as seen from one end face side of the honeycomb structure. 6B is a cross-sectional view schematically showing an A-A ′ cross section shown in FIG. 6A. In addition, the groove part is abbreviate | omitted in FIG. 6A-FIG. 6C.

  In the honeycomb structure, one groove is formed in the bonding layer. The formation position of the groove portion was a position where the distance from the inflow end surface to the groove portion (distance in the cell extending direction of the honeycomb structure) was 76 mm. The width of the groove (the length of the opening of the groove in the circumferential direction of the honeycomb substrate) was 1 mm (the thickness of the bonding layer (referred to as “bonding width” in Tables 1 and 2)). The length of the groove portion (the length of the opening of the groove portion in the direction in which the cells of the honeycomb substrate extend (referred to as “full length direction” in Tables 1 to 3)) was 1 mm. The depth of the groove (referred to as “radial direction” in Tables 1 to 3) was 54 mm. The results are shown in Table 1.

Further, the honeycomb structure had a diameter of 144 mm and a length in the cell extending direction of 152 mm. The honeycomb structure had a partition wall thickness of 0.305 mm and a cell density of 465,000 cells / m ² . Further, the honeycomb structure had a plugging portion depth of 6 mm, a bonding layer thickness of 1 mm, and an outer peripheral coating layer thickness of 1 mm. Further, the honeycomb structure had a partition wall porosity of 60%. The porosity is a value measured with a mercury porosimeter.

  Next, a catalyst was supported on the obtained honeycomb structure to produce a honeycomb catalyst body. As the catalyst, a Cu zeolite SCR catalyst (240 g) was used.

  Next, the produced honeycomb catalyst body was accommodated in a cylindrical can body. The can body had an inflow port, an outflow port, and a body portion therebetween, and a through hole was formed in the body portion. The honeycomb catalyst body was disposed at a position where the groove portion and the through hole of the can body communicated with each other. Thereafter, a thermocouple (K thermocouple: 0.5 mm in diameter) was inserted into the groove to produce an exhaust gas purification device. The arrangement position of the thermocouple was the position indicated by “TC-B1” in FIG. 6C. 6C is a cross-sectional view schematically showing a B-B ′ cross section shown in FIG. 6A.

  The produced exhaust gas purification device was subjected to a “temperature measurement test” by the following method.

[Temperature measurement test]
First, a flow-through honeycomb carrier (DOC) 62 (see FIG. 4) carrying an oxidation catalyst was disposed immediately below a 2-liter diesel engine 60 (see FIG. 4). This DOC was a cylindrical shape having a diameter of 144 mm and a length in the cell extending direction of 76 mm. Further, this DOC had a partition wall thickness of 0.1 mm and a cell density of 620,000 cells / m ² . Then, an exhaust gas purification device 200 (see FIG. 4) is disposed behind the DOC, and a thermocouple 64 (at a position 10 cm behind the honeycomb structure of the exhaust gas purification device (a position 10 cm from the outflow end surface of the honeycomb structure)). (See FIG. 4). FIG. 4 is a schematic diagram showing an arrangement of the engine, the DOC, and the exhaust gas purification device in the temperature measurement test.

  Next, 22 g / L of soot was deposited in the honeycomb catalyst body. The conditions for depositing soot were an engine speed of 2000 rpm and an engine torque of 60 Nm. Next, post-injection was performed for 90 seconds at an engine speed of 1700 rpm and an engine torque of 80 Nm, and then the engine speed was 1000 rpm and the torque was not loaded for 200 seconds (see FIG. 5). The temperature change of the exhaust gas at this time was measured with a thermocouple. FIG. 5 is a graph showing measurement conditions (time, engine torque, engine speed) in the temperature measurement test of Example 5. In FIG. 5, “DPF IN” indicates the temperature of exhaust gas between the flow-through honeycomb carrier 62 and the exhaust gas purification device 200.

  Then, the maximum difference between the estimated original temperature and the actual temperature was calculated. Specifically, the maximum error between the estimated source temperature and the measured temperature is a minimum of two based on the correlation between the “estimated source temperature (estimated source temperature)” and the “actual temperature inside the honeycomb structure (measured temperature)”. This is a value obtained by performing linear approximation by multiplication and calculating the maximum error between the estimated source temperature and the actually measured temperature. In the case of Comparative Example 1, the “estimation source temperature” is a temperature measured by a thermocouple behind the honeycomb structure. “Actual temperature inside the honeycomb structure” means a temperature when the inside of the honeycomb structure (each position of “TC-01”, “TC-02”, and “TC-03”) is directly measured with a thermocouple. It is. The results are shown in Table 1.

  In Table 1, in the case of Comparative Example 1, “estimated source temperature” is a temperature measured by the thermocouple 64 behind the honeycomb structure (position of TC-OUT). “TC-OUT” in the column of “estimated source temperature” indicates a temperature at a position 10 cm from the outflow end face of the honeycomb structure. In the case of Examples 1-5, the temperature of each part shown in the column of "estimated original temperature" is shown. “TC-A1”, “TC-B1”, and “TC-C1” are respectively located in the bonding layer, and indicate a temperature at which the distance L1 from the outer peripheral surface of the honeycomb structure is 54 mm (FIG. 6A, (See FIG. 6C). “TC-B2” is located in the bonding layer and indicates a temperature at which the distance L2 from the outer peripheral surface of the honeycomb structure is 17 mm (see FIGS. 6A and 6C). “TC-B3” is located in the bonding layer and indicates a temperature at which the distance L3 from the outer peripheral surface of the honeycomb structure is 5 mm (see FIGS. 6A and 6C). “TC-B4” is located in the bonding layer and indicates a temperature at which the distance L4 from the outer peripheral surface of the honeycomb structure is 1 mm (see FIGS. 6A and 6C). In Table 1, “the ratio of the distance from the outer periphery to the area centroid and the depth of the groove” indicates the ratio of the depth of the groove to the distance from the outer periphery to the area centroid.

  In Table 1, “TC-01 (inlet side)” in the column of “maximum error between estimated source temperature and measured temperature (° C.)” is the position of “TC-01” shown in FIGS. 6A and 6B. Indicates that the temperature was measured. “TC-02 (center)” indicates that the temperature at the position “TC-02” shown in FIGS. 6A and 6B was measured. “TC-03 (exit side)” indicates that the temperature at the position “TC-03” shown in FIGS. 6A and 6B was measured.

(Examples 2-5, Comparative Example 1)
First, an exhaust gas purification apparatus that satisfies the conditions shown in Table 1 was produced in the same manner as in Example 1. Next, a “temperature measurement test” was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
First, a honeycomb structure satisfying the conditions shown in Table 2 was produced in the same manner as in Example 1. Next, a “punch strength test” was performed on the manufactured honeycomb structure, and “easiness of inserting a thermocouple” was further evaluated.

[Punching strength test]
First, one honeycomb segment fired body of the manufactured honeycomb structure is selected. The honeycomb segment fired body to be selected is assumed to have a groove formed in a joining layer for joining the honeycomb segment fired body and another honeycomb segment fired body. Next, a load is directly applied to one end face of one selected honeycomb segment fired body by a metal cylindrical member having a diameter of 30 mm, and the punching strength of the honeycomb segment fired body is measured. The results are shown in Table 2. The punching strength described in Table 2 is the ratio of the punching strengths of Examples 6 to 11 when the punching strength of Comparative Example 2 is set to 100 (when the punching strength of Comparative Example 2 is used as a reference). It is represented by In addition, when it is 80 to 100, it can be said that “the punching strength is“ good ””. In the case of 0 to 79, it can be said that “the punching strength is“ defective ””.

  In Table 2, “peripheral segment” indicates a honeycomb segment fired body constituting the outer peripheral surface of the honeycomb structure. “Center segment” indicates a honeycomb segment fired body other than “outer peripheral segment”.

[Easy insertion of thermocouple]
A K thermocouple (diameter 0.5 mm) was inserted into the groove of the honeycomb structure five times. Thereafter, the ease of thermocouple insertion (thermocouple insertion ease) was evaluated according to the following evaluation criteria. The case of “relatively easy to insert” is indicated by “◯”, and the case of “can be inserted but takes time for alignment” is indicated by “Δ”.

(Examples 7 to 11, Comparative Example 2)
First, a honeycomb structure satisfying the conditions shown in Table 2 was produced in the same manner as in Example 6. Next, in the same manner as in Example 6, a “punch strength test” was performed, and “thermocouple insertion ease” was further evaluated. The results are shown in Table 2. In Example 9, the same conditions as in Example 5 were adopted for “the position of the groove”. That is, in Example 9, the three groove portions were formed so as to be in the same positions as in Example 5.

(Example 12)
First, an exhaust gas purification apparatus that satisfies the conditions shown in Table 3 was produced in the same manner as in Example 1. Next, a test of “pressure loss” was performed by the following method using the produced exhaust gas purification apparatus. Also in this example, grooves were formed in the bonding layer of the honeycomb substrate.

[Pressure loss]
Air (room temperature (25 ° C.)) was supplied to the exhaust gas purifier at a gas flow rate of 10 m ³ / min, the pressure before and after the exhaust gas purifier was measured, and the pressure loss of the exhaust gas purifier was calculated. The results are shown in Table 3.

( Reference Examples 13-15, Comparative Example 3)
First, an exhaust gas purification apparatus that satisfies the conditions shown in Table 3 was produced in the same manner as in Example 12. Next, a “pressure loss” test was conducted in the same manner as in Example 12. The results are shown in Table 3. In each example, a groove was formed in the bonding layer of the honeycomb substrate. At this time, since the width of the groove portion is larger than the thickness of the bonding layer of the honeycomb substrate (bonding width (1 mm)), the groove portion is formed so as to protrude from the bonding layer (that is, also in a portion other than the bonding layer). It had been.

As is clear from Examples 1 to 12, Reference Examples 13 to 15 and Comparative Examples 1 to 3, the honeycomb structure of the present invention can measure the internal temperature with high accuracy, and a temperature measuring probe such as a thermocouple. It was confirmed that the replacement of was easy.

  The honeycomb structure of the present invention can be used as a filter for purifying exhaust gas discharged from an automobile or the like. The exhaust gas purifying apparatus of the present invention can be used as a filter for purifying exhaust gas discharged from an automobile or the like.

1: partition wall, 2: cell, 10: honeycomb substrate, 11: inflow end surface, 12: outflow end surface, 20: groove portion, 22: honeycomb segment, 24: bonding layer, 25: plugging portion, 26: outer periphery coating layer , 30: Thermocouple, 51: Inlet, 52: Outlet, 53: Body, 55: Through-hole, 56: Expanded tube, 57: Narrow tube, 60: Diesel engine, 62: DOC, 64: Thermocouple , 100, 101: honeycomb structure, 150: can body, 200: exhaust gas purification device, H: groove width, L: groove length, D: groove depth, L1, L2, L3, L4: distance.

Claims (5)

A honeycomb substrate having a porous partition wall that defines a plurality of cells extending from an inflow end surface, which is one end surface into which the fluid flows, to an outflow end surface, which is the other end surface from which the fluid flows out, and serves as a fluid flow path;
An opening on the outflow end face side of the inlet cell, which is a predetermined cell of the honeycomb base material, and a plugging portion disposed in the opening part of the inflow end face of the outlet cell, which is a remaining cell,
In the honeycomb substrate, at least one groove for inserting a temperature measurement probe having an opening on a side surface of the honeycomb substrate is formed,
The circumferential length of the honeycomb base material of the opening of the groove is 0.5 to 20 mm ,
Honeycomb structure is formed so as not to pass through the partition wall of the outer periphery of the front-SL honeycomb substrate. The honeycomb substrate has a plurality of honeycomb segments and a bonding layer that bonds the plurality of honeycomb segments to each other;
The honeycomb structure according to claim 1, wherein the groove is formed only in the bonding layer of the honeycomb substrate. The honeycomb structure according to claim 1 or 2 , wherein the groove has a depth of 1 mm or more. The honeycomb structure according to any one of claims 1 to 3 , wherein a length of the opening of the groove in a cell extending direction of the honeycomb base is 0.5 mm or more. The honeycomb structure according to any one of claims 1 to 4 ,
A can body that has an inflow port through which exhaust gas flows in, an outflow port through which purified exhaust gas flows out, and a body portion located between the inflow port and the outflow port, and stores the honeycomb structure in the body portion And comprising
The can body is formed with at least one through-hole having an opening having an area equal to or larger than an area of the opening of the groove formed in the honeycomb base material of the honeycomb structure in the body portion,
The honeycomb structure is disposed at a position where the groove portion formed in the honeycomb base material and the through hole of the can body communicate with each other.
Further, an exhaust gas purification apparatus comprising a temperature measurement probe that passes through the through hole of the can body and is inserted into the groove portion of the honeycomb base material of the honeycomb structure body to measure the temperature of exhaust gas inside the honeycomb structure body .

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