JP2014148923A - Exhaust gas purification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas purification device capable of improving exhaust gas purification performance while curbing an increase in a pressure loss.SOLUTION: An exhaust gas purification device 100 comprises: a first honeycomb catalyst body 10; a second honeycomb catalyst body 30; and a cylindrical can body 50 which stores the first honeycomb catalyst body 10 and the second honeycomb catalyst body. The can body 50 has a trunk section 51 in a straight shape with a uniform inner diameter. The first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are arranged inside the trunk section 51 of the can body 50 so that: a distance between a first outflow end face 12 of the first honeycomb catalyst body 10 and a second inflow end face 31 of the second honeycomb catalyst body 30 is not more than 50 mm; and an angle α between an extending direction P1 of a first cell 2 of the first honeycomb catalyst body 10 and the extending direction P2 of a second cell 22 of the second honeycomb catalyst body 30 is 2 to 15°.

Description

  The present invention relates to an exhaust gas purification apparatus. More specifically, the present invention relates to an exhaust gas purification device capable of improving exhaust gas purification performance while suppressing an increase in pressure loss.

Exhaust gas discharged from internal combustion engines such as automobile engines contains harmful substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO _X ). Catalytic reactions are widely used to reduce such harmful substances and purify exhaust gas. In this catalytic reaction, it is possible to generate other harmless substances from harmful substances such as carbon monoxide (CO) by a simple means of contacting exhaust gas with the catalyst. Therefore, in an automobile or the like, it is common to purify exhaust gas by installing a catalyst in the exhaust gas exhaust system.

  When a catalyst is installed in an exhaust system of exhaust gas such as an automobile, a honeycomb catalyst body in which a catalyst is supported on a honeycomb structure is used. In the honeycomb catalyst body, a honeycomb structure (honeycomb structure) is formed by the partition walls supporting the catalyst, and each cell surrounded by the partition walls functions as an exhaust gas flow path. In such a honeycomb catalyst body, exhaust gas is divided into a plurality of cells, and the exhaust gas thus subdivided is brought into contact with the catalyst supported on the surfaces of the partition walls. In the honeycomb catalyst body, by treating the exhaust gas in small portions, the contact frequency between the exhaust gas and the catalyst is increased, and as a result, the exhaust gas purification efficiency is improved.

  Conventionally, in an exhaust gas purification apparatus using a honeycomb catalyst body, an exhaust gas purification apparatus in which the honeycomb catalyst body is housed in a metal can has been proposed (see, for example, Patent Documents 1 to 5). By installing such an exhaust gas purification device in the exhaust system of an automobile engine, exhaust gas discharged from the engine can be purified.

  For example, Patent Documents 1 to 3 disclose a technique in which a plurality of honeycomb catalyst bodies are arranged in series with respect to the flow direction of exhaust gas in order to improve exhaust gas purification performance. Patent Document 1 describes that a first exhaust gas purification device and a second exhaust gas purification device are connected by an exhaust pipe to purify exhaust gas in two stages. Patent Documents 2 and 3 disclose exhaust gas purification apparatuses in which a plurality of honeycomb catalyst bodies are arranged in series in a can body. Furthermore, in Patent Document 3, by shifting a plurality of honeycomb catalyst bodies by a predetermined angle around the axial center between the upstream side and the downstream side, the flow resistance increases and the pressure loss increases, and the exhaust gas purification performance of the exhaust gas purification device is improved. The improvement is described (see claim 7 and paragraph [0005] of Patent Document 3).

  Patent Documents 4 and 5 disclose a technique in which a connecting portion is provided between two honeycomb catalyst bodies to change the direction of the two honeycomb catalyst bodies. By configuring in this way, it is said that the vehicle mountability of the exhaust gas purifying device can be improved.

Japanese Patent Laid-Open No. 7-766 JP-A-6-205983 JP 2003-262117 A Japanese Utility Model Publication No. 2-118122 JP 2003-307128 A

  In the exhaust gas purification apparatus in which a plurality of honeycomb catalyst bodies are arranged in series with respect to the flow direction of the exhaust gas as shown in Patent Documents 1 to 3, the exhaust gas purification performance can be improved to some extent, but the exhaust gas purification performance improvement effect There was a problem that was not enough. That is, in the exhaust gas purification apparatus in which a plurality of honeycomb catalyst bodies are arranged in series with respect to the flow direction of the exhaust gas, even if the exhaust gas purification performance is improved by the number of honeycomb catalyst bodies, the plurality of honeycomb catalyst bodies are used. It was not possible to expect a synergistic increase due to the

  Moreover, in the exhaust gas purification apparatus described in Patent Document 3, the effect of improving the exhaust gas purification performance is low as compared with an increase in flow resistance (that is, pressure loss), and the performance is not satisfactory. In addition, in the exhaust gas purification apparatus described in Patent Document 3, when storing a plurality of honeycomb catalyst bodies in a can body, it is difficult to shift only one honeycomb catalyst body by a predetermined angle around the axis, There was also a problem that it was difficult to manufacture the purification device.

  Further, in the exhaust gas purification apparatuses described in Patent Documents 4 and 5, there is a problem that the shape of the can body is complicated and the manufacturing cost is excessive, and the canning operation for housing the honeycomb catalyst body in the can body is difficult. there were.

  The present invention has been made in view of the above-described problems. The present invention provides an exhaust gas purification apparatus capable of improving exhaust gas purification performance while suppressing an increase in pressure loss.

  The present invention provides the following exhaust gas purification apparatus.

[1] A first honeycomb catalyst body, a second honeycomb catalyst body, and a cylindrical can body in which the first honeycomb catalyst body and the second honeycomb catalyst body are accommodated, and the first honeycomb catalyst body A cylindrical first honeycomb structure having a porous first partition wall defining a plurality of first cells extending from the first inflow end surface to the first outflow end surface, and a first outer peripheral wall disposed on the outermost periphery; A first catalyst carried on the first partition of the first honeycomb structure, wherein the second honeycomb catalyst body defines a plurality of second cells extending from the second inflow end surface to the second outflow end surface. A cylindrical second honeycomb structure having a porous second partition wall to be formed and a second outer peripheral wall disposed at the outermost periphery; and a second catalyst supported on the second partition wall of the second honeycomb structure; The can body is disposed on the outlet side of the engine exhaust manifold. A continuous inflow port, a trunk portion in which the first honeycomb catalyst body and the second honeycomb catalyst body are accommodated, and an outflow port for flowing out gas flowing in from the inflow port, The trunk portion has a straight shape with a constant inner diameter of the trunk portion, and the first honeycomb catalyst body and the second honeycomb catalyst body are disposed inside the trunk portion of the first honeycomb catalyst body. The first inflow end surface is located on the inflow side of the can body, the second outflow end surface of the second honeycomb catalyst body is located on the outflow side of the can body, and the first honeycomb contact surface is located. The distance from the first outflow end surface of the medium to the second inflow end surface of the second honeycomb catalyst body is 50 mm or less, and the extending direction of the first cell of the first honeycomb catalyst body and the second honeycomb contact surface. The angle formed by the extending direction of the second cell of the medium is An exhaust gas purification device arranged to be 2 to 15 °.

[2] The extending direction of the first cell of the first honeycomb catalyst body is inclined with respect to the flow direction of the gas flowing in from the inlet of the can body, and the second cell of the second honeycomb catalyst body The exhaust gas purifying apparatus according to [1], wherein the first honeycomb catalyst body and the second honeycomb catalyst body are disposed inside the trunk portion so that the extending directions of the first and second honeycomb catalyst bodies are parallel to each other.

[3] The direction in which the first cells of the first honeycomb catalyst body extend is parallel to the flow direction of the gas flowing in from the inlet of the can body, and the second of the second honeycomb catalyst body. The exhaust gas purifying apparatus according to [1], wherein the first honeycomb catalyst body and the second honeycomb catalyst body are arranged inside the trunk portion so that a cell extending direction is inclined.

[4] The direction in which the first cell of the first honeycomb catalyst body extends and the second cell of the second honeycomb catalyst body extend with respect to the flow direction of the gas flowing in from the inlet of the can body. The exhaust gas purifying apparatus according to [1], wherein the first honeycomb catalyst body and the second honeycomb catalyst body are disposed inside the trunk portion so that the directions thereof are inclined.

[5] In the first honeycomb catalyst body, the first partition walls are arranged so that the extending direction of the first cells is inclined with respect to the extending direction of the first outer peripheral wall formed in a cylindrical shape. The exhaust gas purifying apparatus according to any one of [1] to [4].

[6] In the second honeycomb catalyst body, the second partition walls are arranged so that the extending direction of the second cells is inclined with respect to the extending direction of the second outer peripheral wall formed in a cylindrical shape. The exhaust gas purifying apparatus according to any one of [1] to [5].

  According to the exhaust gas purification apparatus of the present invention, exhaust gas purification performance can be improved while suppressing an increase in pressure loss. That is, in the exhaust gas purification apparatus of the present invention, the first honeycomb catalyst body and the second honeycomb catalyst body are housed in a straight cylindrical can body having a constant inner diameter. For this reason, compared with the conventional exhaust gas purification apparatus in which the can was bent in the flow direction of the exhaust gas, an increase in pressure loss can be suppressed.

  Further, in the exhaust gas purifying apparatus of the present invention, the first honeycomb catalyst body and the second honeycomb catalyst body have a direction in which the first cell of the first honeycomb catalyst body extends and a direction in which the second cell of the second honeycomb catalyst body extends. It arrange | positions in the said can inside so that it may become 2-15 degrees. That is, as compared with a state in which the first honeycomb catalyst body and the second honeycomb catalyst body are arranged in series, at least one of the first honeycomb catalyst body and the second honeycomb catalyst body is gas (specifically, Are arranged in a tilted state with respect to the flow of the exhaust gas). Therefore, the gas discharged from the first outflow end face of the first honeycomb catalyst body flows into the second cell of the second honeycomb catalyst body at an angle of 2 to 15 °. For this reason, the gas flowing into the second cell of the second honeycomb catalyst body can easily come into contact with the second catalyst supported on the second partition wall, and the exhaust gas purification performance by the second catalyst can be improved. Further, since the distance from the first outflow end surface of the first honeycomb catalyst body to the second inflow end surface of the second honeycomb catalyst body is 50 mm or less, the directivity of the gas flowing out from the first honeycomb catalyst body is hardly lost, The exhaust gas purification performance by the second catalyst can be improved satisfactorily. In addition, since the distance from the first outflow end surface of the first honeycomb catalyst body to the second inflow end surface of the second honeycomb catalyst body is 50 mm or less, the exhaust gas purification device becomes compact and the installation space is limited. However, it is possible to realize a size that can be mounted sufficiently.

  Further, in the exhaust gas purification device of the present invention, with the improvement of the exhaust gas purification performance, for example, when the exhaust gas purification performance is the same as the conventional exhaust gas purification device, at least one of the first honeycomb catalyst body and the second honeycomb catalyst body Can be reduced in size. Further, the amount of the catalyst (at least one of the first catalyst and the second catalyst) supported on at least one of the first honeycomb catalyst body and the second honeycomb catalyst body can be reduced. Furthermore, when the size of at least one of the first honeycomb catalyst body and the second honeycomb catalyst body is reduced, the pressure loss of the exhaust gas purification device can be reduced.

It is sectional drawing which shows typically the structure of one Embodiment of the waste gas purification apparatus of this invention, and shows a cross section parallel to the flow direction of the waste gas which flows into a can body. 1 is a perspective view schematically showing a first honeycomb catalyst body used in an embodiment of an exhaust gas purification apparatus of the present invention. FIG. 3 is a plan view schematically showing an inflow end surface of the first honeycomb catalyst body shown in FIG. 2. It is sectional drawing which shows typically the A-A 'cross section of FIG. It is a perspective view which shows typically the 2nd honeycomb catalyst body used for one Embodiment of the exhaust gas purification apparatus of this invention. FIG. 6 is a plan view schematically showing an inflow end surface of the second honeycomb catalyst body shown in FIG. 5. It is sectional drawing which shows the B-B 'cross section of FIG. 6 typically. It is sectional drawing which shows typically the structure of other embodiment of the exhaust gas purification apparatus of this invention, and shows a cross section parallel to the flow direction of the exhaust gas which flows into a can body. It is sectional drawing which shows typically the structure of other embodiment of the exhaust gas purification apparatus of this invention, and shows a cross section parallel to the flow direction of the exhaust gas which flows into a can body. It is sectional drawing which shows typically the structure of other embodiment of the exhaust gas purification apparatus of this invention, and shows a cross section parallel to the flow direction of the exhaust gas which flows into a can body. It is a perspective view which shows typically the 1st honeycomb catalyst body used for the exhaust gas purification apparatus shown in FIG. FIG. 12 is a plan view schematically showing an inflow end surface of the first honeycomb catalyst body shown in FIG. 11. It is sectional drawing which shows typically the C-C 'cross section of FIG.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. The present invention is not limited to the following embodiments. It should be understood that modifications and improvements as appropriate to the following embodiments are also included in the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It is.

(1) Exhaust gas purification device:
As shown in FIG. 1, an embodiment of the exhaust gas purification apparatus of the present invention includes a first honeycomb catalyst body 10, a second honeycomb catalyst body 30, a first honeycomb catalyst body 10, and a second honeycomb catalyst body 30. An exhaust gas purification apparatus 100 including a cylindrical can body 50 to be housed. FIG. 1 is a cross-sectional view schematically showing a configuration of an embodiment of an exhaust gas purifying apparatus of the present invention, showing a cross section parallel to the flow direction of exhaust gas flowing into a can body. As shown in FIG. 1, in the exhaust gas purification apparatus 100 of the present embodiment, two honeycomb catalyst bodies (that is, the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30) are accommodated in a cylindrical can body 50. It has been done.

  As shown in FIGS. 2 to 4, the first honeycomb catalyst body 10 includes a cylindrical first honeycomb structure 4, a first catalyst 7 supported on the first partition wall 1 of the first honeycomb structure 4, It is equipped with. A porous first partition wall 1 in which the first honeycomb structure 4 defines a plurality of first cells 2 extending from the first inflow end surface 11 to the first outflow end surface 12, and a first outer peripheral wall disposed at the outermost periphery 3. The first catalyst 7 is supported on at least one of the surface of the porous first partition wall 1 and the inside of the pores formed in the first partition wall 1. Here, FIG. 2 is a perspective view schematically showing a first honeycomb catalyst body used in one embodiment of the exhaust gas purifying apparatus of the present invention. FIG. 3 is a plan view schematically showing an inflow end face of the first honeycomb catalyst body shown in FIG. FIG. 4 is a cross-sectional view schematically showing the A-A ′ cross section of FIG. 3.

  Further, as shown in FIGS. 5 to 7, the second honeycomb catalyst body 30 includes a cylindrical second honeycomb structure 24 and a second catalyst 27 supported on the second partition wall 21 of the second honeycomb structure 24. And. A porous second partition wall 21 in which the second honeycomb structure 24 defines a plurality of second cells 22 extending from the second inflow end surface 31 to the second outflow end surface 32, and a second outer peripheral wall disposed at the outermost periphery 23. The second catalyst 27 is supported on at least one of the surface of the porous second partition wall 21 and the inside of the pore formed in the second partition wall 21. Here, FIG. 5 is a perspective view schematically showing a second honeycomb catalyst body used in one embodiment of the exhaust gas purifying apparatus of the present invention. FIG. 6 is a plan view schematically showing the inflow end face of the second honeycomb catalyst body shown in FIG. FIG. 7 is a cross-sectional view schematically showing the B-B ′ cross section of FIG. 6.

  Further, as shown in FIG. 1, the can body 50 includes an inflow port 52, a body portion 51 in which the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are accommodated, and an outflow port 53. It is. The inflow port 52 is connected to an outlet side of an engine exhaust manifold (not shown) via an exhaust pipe or the like, and introduces exhaust gas (gas G0) discharged from the internal combustion engine or the like into the can body 50. . The outflow port 53 purifies the gas G0 flowing in from the inflow port 52 and flows out as purified gas (gas G3). In the exhaust gas purifying apparatus 100 of the present embodiment, the trunk portion 51 of the can body 50 has a straight shape in which the inner diameter of the trunk portion 51 is constant. That is, the body 51 in which the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are housed has a straight straight pipe shape. The first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are housed in the straight body portion 51. At this time, the first inflow end surface 11 of the first honeycomb catalyst body 10 is positioned on the inflow port 52 side of the can body 50, and the second outflow end surface 32 of the second honeycomb catalyst body 30 is the outflow port 53 of the can body 50. Located on the side. Further, in the exhaust gas purification apparatus 100 of the present embodiment, the distance t from the first outflow end surface 12 of the first honeycomb catalyst body 10 to the second inflow end surface 31 of the second honeycomb catalyst body 30 is 50 mm or less.

  Further, the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 have a direction P1 in which the first cells 2 of the first honeycomb catalyst body 10 extend and a direction P2 in which the second cells 22 of the second honeycomb catalyst body 30 extend. It arrange | positions so that the angle (alpha) which becomes may become 2-15 degrees. The angle α is an angle when the direction P1 in which the first cell 2 extends is parallel to the direction P2 in which the second cell 22 extends is 0 °. For example, when the angle α between the extending direction P1 of the first cell 2 and the extending direction P2 of the second cell 22 is 15 °, the extending direction of the second cell 22 with respect to the extending direction P1 of the first cell 2 That is, P2 is inclined by 15 °. Since this angle α is an angle determined by the extending direction P1 of the first cell 2 and the extending direction P2 of the second cell 22, when the angle α is 15 °, the extending direction of the second cell 22 The extending direction P1 of the first cell 2 may be inclined by 15 ° with respect to P2. As described above, in the exhaust gas purification apparatus 100 of the present embodiment, the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are in a state where the straight honeycomb body 51 is inclined with respect to the angle α from the series state. Is housed inside. In the present invention, the above-mentioned “angle α” is a plane in which the first axis extending in the direction P1 and the second axis extending in the direction P2 are on the same plane. It is the angle made with the second axis.

  The gas G0 that has flowed into the can body 50 from the inflow port 52 first flows into the first cell 2 from the first inflow end face 11 of the first honeycomb catalyst body 10, passes through the first cell 2, and passes through the first cell 2. It flows out from the first outflow end face 12 of the honeycomb catalyst body 10. A gas passing through the first honeycomb catalyst body 10 is referred to as a gas G1. Then, the gas G1 flowing out from the first outflow end face 12 of the first honeycomb catalyst body 10 flows into the second cell 22 from the second inflow end face 31 of the second honeycomb catalyst body 30 and passes through the second cell 22. Then, it flows out from the second outflow end face 32 of the second honeycomb catalyst body 30. The gas that passes through the second honeycomb catalyst body 30 is referred to as gas G2. The gas G3 flowing out from the second outflow end face 32 finally flows out from the outlet 53 of the can body 50.

The exhaust gas discharged from the internal combustion engine or the like (that is, the gas G0 flowing into the can 50 from the inflow port 52) includes carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO _X ), and the like. May contain harmful substances. In the exhaust gas purification apparatus 100 of the present embodiment, the first catalyst 7 supported on the first partition wall 1 of the first honeycomb structure 4 and the second catalyst supported on the second partition wall 21 of the second honeycomb structure 24. 27 removes the harmful substances. In the exhaust gas purification apparatus 100 of the present embodiment, as described above, the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 have the extending direction P1 of the first cell 2 and the extending direction P2 of the second cell 22. It arrange | positions so that the angle (alpha) which becomes may become 2-15 degrees. Therefore, the gas G1 flowing out from the first outflow end face 12 of the first honeycomb catalyst body 10 is likely to collide with the second partition wall 21 when flowing in from the second inflow end face 31 of the second honeycomb catalyst body 30; Further, the gas G2 flow in the second cell 22 is likely to be disturbed by the collision. As a result, the exhaust gas purification performance of the second catalyst 27 carried on the second partition wall 21 is improved. In particular, since the distance t from the first outflow end face 12 of the first honeycomb catalyst body 10 to the second inflow end face 31 of the second honeycomb catalyst body 30 is 50 mm or less, the gas G1 is in the direction P1 in which the first cell 2 extends. It becomes easy to reach the second inflow end face 31 of the second honeycomb catalyst body 30 in the state of being oriented in the direction. Moreover, since the interval t is 50 mm or less, the exhaust gas purification apparatus 100 becomes compact, and a size that can be sufficiently mounted even in an in-vehicle application with a limited installation space can be realized.

  On the other hand, when the direction P1 in which the first cell 2 extends and the direction P2 in which the second cell 22 extend are parallel as in the conventional exhaust gas purification device, the first honeycomb catalyst body 10 flows out from the first outflow end face 12. The gas G1 reaches the second inflow end surface 31 of the second honeycomb catalyst body 30 in a state where the gas G1 is directed in the extending direction P2 of the second cell 22. For this reason, the gas G2 passing through the second honeycomb catalyst body 30 passes through the second cell 22 straightly. Therefore, the collision between the gas G2 and the second partition wall 21 (in other words, the second catalyst 27 carried on the second partition wall 21) is not promoted, and it is difficult to improve the exhaust gas purification performance.

  Further, in the exhaust gas purification apparatus 100 shown in FIG. 1, the first honeycomb catalyst body is inclined such that the direction P1 in which the first cell 2 extends is inclined with respect to the flow direction P3 of the gas G0 flowing from the inlet 52 of the can body 50. 10 is arranged. For this reason, in the exhaust gas purification apparatus 100 shown in FIG. 1, in addition to the exhaust gas purification performance improvement effect of the second catalyst 27 described above, the exhaust gas purification performance improvement effect of the first catalyst 7 can be further expected. In the exhaust gas purifying apparatus 100 shown in FIG. 1, the second honeycomb so that the extending direction P2 of the second cell 22 is parallel to the flowing direction P3 of the gas G0 flowing from the inlet 52 of the can body 50. A catalyst body 30 is disposed.

  Furthermore, in the exhaust gas purification apparatus 100 of the present embodiment, with the improvement of the exhaust gas purification performance, for example, when the exhaust gas purification performance is the same as that of the conventional exhaust gas purification apparatus, the first honeycomb catalyst body 10 and the second honeycomb catalyst body The size of at least one of 30 can be reduced. In addition, the amount of the catalyst (at least one of the first catalyst 7 and the second catalyst 27) supported on at least one of the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 can be reduced. Furthermore, when the size of at least one of the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 is reduced, the pressure loss of the exhaust gas purification device 100 can be reduced.

  The exhaust gas purification apparatus of the present invention may be an exhaust gas purification apparatus 101 as shown in FIG. In the exhaust gas purification apparatus 101 shown in FIG. 8, the second honeycomb catalyst body 30 is arranged so that the direction P2 in which the second cell 22 extends is inclined with respect to the flow direction P3 of the gas G0 flowing from the inlet 52 of the can body 50. Has been. Therefore, the gas G1 flowing out from the first outflow end face 12 of the first honeycomb catalyst body 10 is likely to collide with the second partition wall 21 when flowing in from the second inflow end face 31 of the second honeycomb catalyst body 30; Further, the gas G2 flow in the second cell 22 is likely to be disturbed by the collision. As a result, the exhaust gas purification performance of the second catalyst 27 carried on the second partition wall 21 is improved. In the exhaust gas purification apparatus 101 shown in FIG. 8, the first honeycomb catalyst body is arranged such that the direction P1 in which the first cell 2 extends is parallel to the flow direction P3 of the gas G0 flowing from the inlet 52 of the can body 50. 10 is arranged. Here, FIG. 8 is a cross-sectional view schematically showing a configuration of another embodiment of the exhaust gas purifying apparatus of the present invention, and shows a cross section parallel to the flow direction of the exhaust gas flowing into the can body. In FIG. 8, the same components as those in the exhaust gas purification apparatus 100 shown in FIG.

  Furthermore, the exhaust gas purification apparatus of the present invention may be an exhaust gas purification apparatus 102 as shown in FIG. In the exhaust gas purification apparatus 102 shown in FIG. 9, the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are arranged so as to be inclined with respect to the flow direction P3 of the gas G0 flowing from the inlet 52. Yes. That is, the first honeycomb catalyst body 10 is arranged such that the direction P1 in which the first cell 2 extends is inclined with respect to the flow direction P3 of the gas G0 flowing from the inlet 52 of the can body 50. Further, the second honeycomb catalyst body 30 is arranged so that the direction P2 in which the second cell 22 extends is inclined with respect to the flow direction P3 of the gas G0 flowing from the inlet 52 of the can body 50. Also in the exhaust gas purification device 102 shown in FIG. 9, the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are formed by an angle between the extending direction P1 of the first cell 2 and the extending direction P2 of the second cell 22. It arrange | positions so that (alpha) may be 2-15 degrees. Also in the exhaust gas purification apparatus 102 configured as described above, the same effect as that of the exhaust gas purification apparatus 100 shown in FIG. 1 can be obtained. Here, FIG. 9 is a cross-sectional view schematically showing a configuration of still another embodiment of the exhaust gas purifying apparatus of the present invention, and shows a cross section parallel to the flow direction of the exhaust gas flowing into the can body. In FIG. 9, the same components as those in the exhaust gas purification apparatus 100 shown in FIG.

  If the angle α formed between the extending direction P1 of the first cell 2 and the extending direction P2 of the second cell 22 is less than 2 °, the gas G1 flowing out from the first outflow end face 12 of the first honeycomb catalyst body 10 is reduced. It becomes difficult to collide with the second partition wall 21. Further, when the angle α formed between the extending direction P1 of the first cell 2 and the extending direction P2 of the second cell 22 exceeds 15 °, the inflow resistance of the gas G2 to the second honeycomb catalyst body 30 increases, and the exhaust gas purification is performed. The pressure loss of the device may increase. The angle α formed between the extending direction P1 of the first cell 2 and the extending direction P2 of the second cell 22 is more preferably 2 to 10 °, and further preferably 3 to 6 °. By comprising in this way, exhaust gas purification performance can be improved more suitably, suppressing the increase in pressure loss.

  Further, in the exhaust gas purification apparatus 100 of the present embodiment, the interval t (hereinafter simply referred to as “interval t”) from the first outflow end surface 12 of the first honeycomb catalyst body 10 to the second inflow end surface 31 of the second honeycomb catalyst body 30. Is sometimes 50 mm or less. The interval t means the shortest distance from the first outflow end surface 12 to the second inflow end surface 31 in the first outflow end surface 12 and the second inflow end surface 31 facing each other. When this interval t exceeds 50 mm, the directivity of the gas G1 flowing out from the first outflow end face 12 of the first honeycomb catalyst body 10 is lost, and the effect of improving the exhaust gas purification performance of the second catalyst 27 is sufficiently exhibited. There are things that do not. The interval t is preferably 2 to 50 mm, and more preferably 2 to 40 mm. By setting the interval t to 2 mm or more, the contact between the first outflow end surface 12 of the first honeycomb catalyst body 10 and the second inflow end surface 31 of the second honeycomb catalyst body 30 can be effectively prevented. That is, when the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are housed in the body portion 51 of the can body 50, the collision between the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 occurs. It can be effectively prevented.

  Further, in the exhaust gas purification apparatus 100 of the present embodiment, the angle β formed by the flow direction P3 of the gas G0 flowing from the inlet 52 of the can body 50 and the extending direction P1 of the first cell 2 is 0 to 15 °. Is preferably 0 ° to 10 °, and particularly preferably 0 ° to 6 °. If the angle β between the flow direction P3 of the gas G0 and the direction P1 in which the first cell 2 extends becomes too large, the inflow resistance of the gas G1 to the first honeycomb catalyst body 10 increases, and the pressure loss of the exhaust gas purification device May increase.

  In the exhaust gas purification apparatus 100 shown in FIG. 1, the first honeycomb catalyst body 10 is arranged such that the extending direction of the first cells 2 is parallel to the extending direction of the first outer peripheral wall 3 formed in a cylindrical shape. A first partition 1 is disposed. Therefore, in the first honeycomb catalyst body 10, the direction from the first inflow end surface 11 toward the first outflow end surface 12 is the direction P1 in which the first cells 2 extend. In the exhaust gas purification apparatus 100 shown in FIG. 1, the extending direction of the second cells 22 is also parallel to the extending direction of the second outer peripheral wall 23 formed in the cylindrical shape in the second honeycomb catalyst body 30. The 2nd partition 21 is arrange | positioned so that it may become. Therefore, also in the second honeycomb catalyst body 30, the direction from the second inflow end surface 31 toward the second outflow end surface 32 is the direction P2 in which the second cells 22 extend. In the exhaust gas purification apparatus 100 shown in FIG. 1, the periphery of the outer peripheral surface of the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 is wrapped with gripping materials 55 a and 55 b, and the inside of the body portion 51 of the can body 50 is The one honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are held. Examples of the gripping materials 55a and 55b include a ceramic fiber mat.

  In the exhaust gas purifying apparatus 100 shown in FIG. 1, the first cell 2 extends in the flow direction P3 of the gas G0 by using the gripping material 55a whose gripping portion has a different thickness toward the flow direction P3 of the gas G0. The first honeycomb catalyst body 10 is held so that the direction P1 is inclined. That is, when the first honeycomb catalyst body 10 is arranged so that the extending direction P1 of the first cell 2 is inclined with respect to the flow direction P3 of the gas G0, the inner surface of the trunk portion 51 of the can body 50 and the first honeycomb A gripping material 55 a is arranged so as to fill a gap with the outer peripheral surface of the catalyst body 10. On the other hand, for the second honeycomb catalyst body 30, by using the holding material 55b having a constant thickness with respect to the flow direction P3 of the gas G0, the extending direction P2 of the second cell 22 with respect to the flow direction P3 of the gas G0 They are held in parallel. Also in the exhaust gas purification apparatuses 101 and 102 shown in FIGS. 8 and 9, the thicknesses of the gripping materials 55 a and 55 b are adjusted toward the gas P <b> 0 flow direction P <b> 3, and the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30. The tilt is adjusted.

  In the exhaust gas purification apparatus of the present invention, the first partition wall is disposed so that the first honeycomb catalyst body is inclined in the direction in which the first cell extends with respect to the direction in which the first outer peripheral wall formed in a cylindrical shape extends. May be. Further, in the exhaust gas purification apparatus of the present invention, the second partition wall is disposed so that the second honeycomb catalyst body is inclined in the direction in which the second cell extends with respect to the direction in which the second outer peripheral wall formed in a cylindrical shape extends. May be. For example, in the exhaust gas purifying apparatus 103 shown in FIG. 10, the first partition 1a is arranged such that the extending direction of the first cell 2a is inclined with respect to the extending direction of the first outer peripheral wall 3a formed in a cylindrical shape. An example of using one honeycomb catalyst body 10a is shown. That is, as shown in FIGS. 11 to 13, the first honeycomb catalyst body 10a includes a tubular first honeycomb structure 4a and the first catalyst 7 supported on the first partition walls 1a of the first honeycomb structure 4a. And. The first honeycomb structure 4a includes a porous first partition wall 1a that partitions and forms a plurality of first cells 2a, and a first outer peripheral wall 3a that is disposed on the outermost periphery, and a direction in which the first outer peripheral wall 3a extends. On the other hand, the 1st partition 1a is arrange | positioned so that the extending direction of the 1st cell 2a may incline. The direction in which the first outer peripheral wall 3a extends is the axial direction of the cylindrical first honeycomb structure 4a. In other words, the direction is from the first inflow end surface 11a toward the first outflow end surface 12a. Like the first honeycomb catalyst body 10 shown in FIGS. 2 to 5, the first catalyst 7 is formed on at least one of the surface of the porous first partition wall 1 a and the inside of the pores formed in the first partition wall 1 a. It is supported. In the exhaust gas purifying apparatus 103 shown in FIG. 10, the first honeycomb catalyst body 10 a and the second honeycomb catalyst body 30 are arranged in series inside the trunk portion 51 of the can body 50. That is, the first outflow end face 12a of the first honeycomb catalyst body 10a and the second inflow end face 31 of the second honeycomb catalyst body 30 are arranged so as to face each other in parallel. However, since the first partition 1a is arranged so that the extending direction P1 of the first cell 2a is inclined with respect to the extending direction of the first outer peripheral wall 3a, the extending direction P1 of the first cell 2a and the second cell 22 The angle α formed with the extending direction P2 can be 2 to 15 °.

  In the exhaust gas purifying apparatus 103 shown in FIG. 10, the first honeycomb catalyst body 10a and the second honeycomb catalyst body 30 are arranged in series inside the body portion 51 of the can body 50, so that the gripping materials 55a and 55b are used. One having a constant thickness can be used. Further, in the exhaust gas purifying apparatus 103 shown in FIG. 10, the first honeycomb catalyst body 10a and the second honeycomb catalyst body 30 in which the gripping materials 55a and 55b are disposed in the body portion 51 of the can body 50 can be easily stored. Become.

  Here, FIG. 10 is a cross-sectional view schematically showing a configuration of still another embodiment of the exhaust gas purifying apparatus of the present invention, and shows a cross section parallel to the flow direction of the exhaust gas flowing into the can body. FIG. 11 is a perspective view schematically showing a first honeycomb catalyst body used in the exhaust gas purification apparatus shown in FIG. FIG. 12 is a plan view schematically showing the inflow end face of the first honeycomb catalyst body shown in FIG. FIG. 13 is a cross-sectional view schematically showing the C-C ′ cross section of FIG. 12. In FIG. 10, the same components as those in the exhaust gas purification apparatus 100 shown in FIG. Moreover, in FIGS. 11-13, about the component similar to the 1st honeycomb catalyst body 10 shown in FIGS. 2-4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  Further, in FIG. 10, the example in which the first honeycomb catalyst body 10 a illustrated in FIGS. 11 to 13 is used has been described. However, as the second honeycomb catalyst body 30, the extending direction P <b> 2 of the second cell 22 is inclined. Alternatively, the one in which the second partition wall 21 is disposed may be used. Although not shown, the first honeycomb catalyst body in which the first partition walls are arranged so that the direction in which the first cells extend is inclined, and the first honeycomb catalyst body in which the second partition walls are arranged so that the direction in which the second cells extend is inclined. A two-honeycomb catalyst body may be used in combination.

  Hereinafter, the exhaust gas purification apparatus of the present embodiment will be described in more detail for each component.

(1-1) Can body:
As shown in FIG. 1, a can body 50 is a casing (in other words, an exterior) in the exhaust gas purification apparatus 100 of the present embodiment, and the can body 50 is configured to be connectable to an engine exhaust manifold. . That is, the can body 50 has an inlet 52 connected to the outlet side of the engine exhaust manifold, and an outlet 53 through which the gas G3 that has passed through the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 flows out. Yes. The first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are accommodated in the body portion 51 of the can body 50. When exhaust gas is purified by the exhaust gas purification apparatus 100 of the present embodiment, the inlet 52 of the can body 50 is connected to the outlet side of the engine exhaust manifold. The exhaust gas (gas G0) flowing in from the inlet 52 of the can body 50 is purified by the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 housed in the can body 50. As described above, the trunk portion 51 of the can body 50 has a straight shape in which the inner diameter of the trunk portion 51 is constant.

  The can body 50 shown in FIG. 1 has an inlet 52 so as to match the diameter of the engine exhaust manifold and the diameter of the exhaust system from which the purified exhaust gas is discharged (for example, the diameter of the exhaust pipe, the muffler, etc.). And the outflow port 53 is formed.

  Further, the body 51 of the can body 50, the inlet 52 and the outlet 53 of the can 50 are an expanded pipe part whose diameter gradually increases from the inlet 52, and a narrow pipe part whose diameter gradually decreases toward the outlet 53. May further be included. For example, when the diameter of the engine exhaust manifold, the exhaust pipe, the muffler, etc. is the same as the diameter of the body portion 51 of the can body 50, the above-described expanded tube portion and narrow tube portion may not be particularly provided. Good.

  The material of the can body is preferably made of, for example, stainless steel, and particularly preferably made of chromium or chromium / nickel stainless steel.

  Examples of the method for holding the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 inside the body portion 51 of the can body 50 include the following methods. That is, a method of wrapping the periphery of the outer peripheral surfaces of the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 with gripping materials 55a and 55b such as ceramic fiber mats and press-fitting into the body 51 of the can body 50, etc. Can be mentioned. By using holding materials 55a and 55b such as ceramic fiber mats, the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 can be protected from external impacts and insulated. After the first honeycomb catalyst body 10 and the second honeycomb catalyst body 30 are held inside the trunk portion 51, a previously produced expanded tube portion or narrow tube portion may be welded to the trunk portion 51, or The can 50 may be expanded or narrowed by spinning or the like.

  As the gripping materials 55a and 55b, the above-described ceramic fiber mat can be cited as a suitable example. Such a ceramic fiber mat is easy to obtain and process, and has sufficient heat resistance and cushioning properties. Examples of the ceramic fiber mat include a non-thermal expansion mat substantially free of vermiculite, a low thermal expansion mat including a small amount of vermiculite, and the like.

(1-2) First honeycomb catalyst body:
As shown in FIGS. 2 to 4, the first honeycomb catalyst body 10 includes a cylindrical first honeycomb structure 4, a first catalyst 7 supported on the first partition wall 1 of the first honeycomb structure 4, It is equipped with. The first honeycomb structure 4 includes a porous first partition wall 1 that partitions and forms a plurality of first cells 2, and a first outer peripheral wall 3 disposed on the outermost periphery. The first catalyst 7 is supported on at least one of the surface of the porous first partition wall 1 and the inside of the pores formed in the first partition wall 1.

  The thickness of the first partition wall 1 is preferably 0.035 to 0.35 mm, and more preferably 0.045 to 0.26 mm. When the thickness of the first partition wall is less than 0.035 mm, the strength of the first honeycomb catalyst body 10 may be lowered. On the other hand, if the thickness of the first partition wall exceeds 0.35 mm, the pressure loss of the exhaust gas purification device increases, which may affect the engine output reduction.

The cell density of the first honeycomb structure 4 constituting the first honeycomb catalyst body 10, more preferably from preferably from 12 to 200 pieces / cm ^2, is 15 to 190 pieces / cm ^2, 30 to 160 It is particularly preferable that the number of particles / cm ² . With this configuration, the contact area between the gas G1 and the first catalyst 7 supported on the first partition wall 1 can be increased, and the pressure loss of the first honeycomb catalyst body 10 increases excessively. This can be suppressed. When the cell density is less than 12 cells / cm ² , the strength of the first honeycomb catalyst body 10 may be reduced. When the cell density exceeds 200 cells / cm ² , the pressure loss of the exhaust gas purification device may increase.

  The porosity of the first partition wall 1 is preferably 20 to 65%, more preferably 30 to 50%, and particularly preferably 30 to 45%. If the porosity is less than 20%, it may be difficult to support the catalyst or the heat capacity may increase. On the other hand, if the porosity exceeds 65%, the first honeycomb catalyst body 10 may become brittle and easily lost. Moreover, it is preferable that the average pore diameter of the 1st partition 1 is 1-20 micrometers, and it is still more preferable that it is 1-10 micrometers. The porosity and average pore diameter of the first partition are values measured with a mercury porosimeter.

  The length from the first inflow end surface 11 to the first outflow end surface 12 of the first honeycomb catalyst body 10 is preferably 30 to 350 mm, but is not limited to this, so as to obtain an optimal purification performance as an exhaust gas purification system. What is necessary is just to select suitably.

  The shape of the first cell 2 of the first honeycomb structure 4 is not particularly limited, but in a cross section orthogonal to the central axis, a polygon such as a triangle, a quadrangle, a pentagon, a hexagon, an octagon, a circle, or an ellipse, Alternatively, a combination of a quadrangle and a hexagon or octagon is preferable. Other shapes may be sufficient as the shape of the 1st cell 2. FIG. The shape of the first cell 2 is more preferably a quadrangle, a hexagon, or the like.

  The first partition wall 1 of the first honeycomb structure 4 is preferably composed mainly of ceramic. Specifically, the material of the first partition 1 is silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, zeolite, vanadium. And at least one selected from the group consisting of aluminum titanate. Among these, cordierite having a small thermal expansion coefficient and excellent thermal shock resistance is preferable. In addition, the phrase “having ceramic as a main component” means containing 50% by mass or more of the entire ceramic.

  The first honeycomb structure may be a segment structure honeycomb structure. Specifically, the first honeycomb structure having a segment structure includes a honeycomb structure in which a plurality of first honeycomb segments are joined in a state of being arranged adjacent to each other so that their side faces face each other. be able to. The first honeycomb segment is disposed so as to surround the porous first partition walls and the first partition walls that form a plurality of first cells that form fluid flow paths extending from the first inflow side end surface to the first outflow side end surface. The first outer wall is provided. The first outer wall of the first honeycomb segment becomes the side surface of the first honeycomb segment. The first outer peripheral wall is disposed on the outermost periphery of the joined body in which the plurality of first honeycomb segments are joined. In addition, after processing the outer peripheral part of the joined body in which a plurality of first honeycomb segments are joined by grinding or the like to make the shape of the cross section perpendicular to the extending direction of the first cell a circle or the like, a ceramic material is applied to the outermost periphery. You may arrange | position a 1st outer peripheral wall by doing. Such a so-called segmented first honeycomb structure can obtain the same effects as the so-called integrated first honeycomb structure 4 as shown in FIGS. .

  The amount of the first catalyst supported on the first partition walls of the first honeycomb structure (hereinafter referred to as “the amount of the first catalyst supported”) is not particularly limited. The supported amount of the first catalyst is preferably 20 to 400 g / L, more preferably 30 to 300 g / L, and particularly preferably 40 to 250 g / L.

  As the first catalyst supported on the first partition wall of the first honeycomb catalyst body, for example, a noble metal such as platinum (Pt), palladium (Pd), rhodium (Rh) is supported on a support made of a heat-resistant inorganic oxide. Can be used. Examples of the “support made of heat-resistant inorganic oxide” include a support made of alumina, titania, silica, zirconia, cerium oxide, tungsten oxide, zeolite, transition metal oxide, rare earth oxide, or a mixture thereof. Can do.

  When the loading amount of the first catalyst exceeds 400 g / L, it can be expected that the purification performance by the first honeycomb catalyst body is improved. On the other hand, the cross-sectional area of the first cell is reduced and the pressure loss is increased. May end up. Further, when the loading amount of the first catalyst is less than 20 g / L, the purification performance by the first honeycomb catalyst body may not be sufficiently exhibited. In the present specification, the supported amount (g / L) refers to the amount (g) of the catalyst supported per unit volume (1 L) of the honeycomb structure part. That is, the amount of the first catalyst supported on the first partition walls of the first honeycomb catalyst body is the amount (g) of the first catalyst supported per unit volume (1 L) of the first honeycomb structure. It is. The method for supporting the first catalyst on the first partition walls of the first honeycomb structure is not particularly limited, and can be performed according to a conventionally known method.

(1-3) Second honeycomb catalyst body:
As shown in FIG. 5 to FIG. 7, the second honeycomb catalyst body 30 includes a cylindrical second honeycomb structure 24, a second catalyst 27 supported on the second partition wall 21 of the second honeycomb structure 24, It is equipped with. The second honeycomb structure 24 includes a porous second partition wall 21 that partitions and forms a plurality of second cells 22, and a second outer peripheral wall 23 disposed on the outermost periphery. The second catalyst 27 is supported on at least one of the surface of the porous second partition wall 21 and the inside of the pore formed in the second partition wall 21.

  The thickness of the second partition wall 21 is preferably 0.035 to 0.35 mm, and more preferably 0.045 to 0.26 mm. If the thickness of the second partition wall 21 is less than 0.035 mm, the strength of the second honeycomb catalyst body 30 may be reduced. On the other hand, if the thickness of the second partition wall 21 exceeds 0.35 mm, the pressure loss of the exhaust gas purification device increases, which may affect the engine output reduction.

The cell density of the second honeycomb structure 24 constituting the second honeycomb catalyst body 30, more preferably from preferably from 12 to 200 pieces / cm ^2, is 15 to 190 pieces / cm ^2, 30 to 160 It is particularly preferable that the number of particles / cm ² . With this configuration, the contact area between the second catalyst 27 carried on the second partition wall 21 and the gas G2 can be increased, and the pressure loss of the second honeycomb catalyst body 30 is excessively increased. This can be suppressed. When the cell density is less than 12 cells / cm ² , the strength of the second honeycomb catalyst body 30 may be reduced. When the cell density exceeds 200 cells / cm ² , the pressure loss of the exhaust gas purification device may increase.

  The porosity of the second partition wall 21 is preferably 20 to 65%, more preferably 30 to 50%, and particularly preferably 30 to 45%. If the porosity is less than 20%, it may be difficult to support the catalyst or the heat capacity may increase. On the other hand, if the porosity exceeds 65%, the second honeycomb catalyst body 30 may become brittle and easily missing. Moreover, it is preferable that the average pore diameter of the 2nd partition 21 is 1-20 micrometers, and it is still more preferable that it is 1-10 micrometers. The porosity and average pore diameter of the second partition wall are values measured with a mercury porosimeter.

  The length from the second inflow end surface 31 to the second outflow end surface 32 of the second honeycomb catalyst body 30 is preferably 30 to 350 mm. However, the length is not limited to this, and an optimum purification performance as an exhaust gas purification system is obtained. What is necessary is just to select suitably.

  The shape of the second cell 22 of the second honeycomb structure 24 is not particularly limited, but in a cross section perpendicular to the central axis, a polygon such as a triangle, a quadrangle, a pentagon, a hexagon, an octagon, a circle, or an ellipse, Alternatively, a combination of a quadrangle and a hexagon or octagon is preferable. Other shapes may be sufficient as the shape of the 2nd cell 22. FIG. The shape of the second cell 22 is more preferably a quadrangle, a hexagon, or the like.

  The second partition wall 21 of the second honeycomb structure 24 is preferably composed mainly of ceramic. Specifically, the material of the second partition wall 21 is silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, zeolite, vanadium. And at least one selected from the group consisting of aluminum titanate. Among these, cordierite having a small thermal expansion coefficient and excellent thermal shock resistance is preferable.

  The second honeycomb structure may be a segment structure honeycomb structure. Specifically, the second honeycomb structure having a segment structure includes a honeycomb structure in which a plurality of second honeycomb segments are joined in a state of being arranged adjacent to each other so that their side faces face each other. be able to. The second honeycomb segment is disposed so as to surround the porous second partition wall and the second partition wall that form a plurality of second cells that form a fluid flow path extending from the second inflow side end surface to the second outflow side end surface. Having a second outer wall. The second outer wall of the second honeycomb segment becomes the side surface of the second honeycomb segment. A second outer peripheral wall is disposed on the outermost periphery of the joined body obtained by joining the plurality of second honeycomb segments. Also, after processing the outer periphery of the joined body in which a plurality of second honeycomb segments are joined by grinding or the like to make the shape of the cross section perpendicular to the extending direction of the second cell a circle or the like, a ceramic material is applied to the outermost periphery. You may arrange | position a 2nd outer peripheral wall by doing. Even in such a so-called second honeycomb structure having a segment structure, the same effects as those of the so-called integral second honeycomb structure 24 as shown in FIGS. 5 to 7 can be obtained. .

  The amount of the second catalyst supported on the second partition walls of the second honeycomb structure (hereinafter referred to as “the amount of the second catalyst supported”) is not particularly limited. The amount of the second catalyst supported is preferably 20 to 400 g / L, more preferably 30 to 300 g / L, and particularly preferably 40 to 250 g / L.

  As the second catalyst supported on the second partition wall of the second honeycomb catalyst body, for example, a noble metal such as platinum (Pt), palladium (Pd), rhodium (Rh) is supported on a support made of a heat-resistant inorganic oxide. Can be used. Examples of the “support made of heat-resistant inorganic oxide” include a support made of alumina, titania, silica, zirconia, cerium oxide, tungsten oxide, zeolite, transition metal oxide, rare earth oxide, or a mixture thereof. Can do.

  When the loading amount of the second catalyst exceeds 400 g / L, improvement in purification performance by the second honeycomb catalyst body can be expected, but on the other hand, the cross-sectional area of the second cell is reduced and the pressure loss is increased. May end up. Further, when the loading amount of the second catalyst is less than 20 g / L, the purification performance by the second honeycomb catalyst body may not be sufficiently exhibited. The method for supporting the second catalyst on the second partition walls of the second honeycomb structure is not particularly limited and can be performed according to a conventionally known method.

(2) Manufacturing method of exhaust gas purification device:
Next, the method for manufacturing the exhaust gas purification apparatus of the present invention will be described by taking a method for manufacturing the exhaust gas purification apparatus 100 of the present embodiment as shown in FIG. 1 as an example.

  When manufacturing the exhaust gas purification apparatus 100 of the present embodiment, first, two honeycomb structures having porous partition walls and outer peripheral walls are manufactured. One honeycomb structure becomes the first honeycomb structure of the first honeycomb catalyst body, and the other honeycomb structure becomes the second honeycomb structure of the second honeycomb catalyst body.

  When producing a honeycomb structure, first, a forming raw material containing a ceramic raw material is mixed and kneaded to obtain a clay. As ceramic raw materials, silicon carbide, silicon-silicon carbide based composite materials, cordierite, cordierite forming raw materials, mullite, alumina, spinel, silicon carbide cordierite based composite materials, lithium aluminum silicate, zeolite, vanadium and aluminum titanate It is preferable to use at least one selected from the group consisting of: The cordierite forming raw material is a ceramic raw material blended so as to have a chemical composition that falls within the range of 42 to 56% by mass of silica, 30 to 45% by mass of alumina, and 12 to 16% by mass of magnesia. The cordierite forming raw material is fired to become cordierite.

  The forming raw material is preferably prepared by further mixing the ceramic raw material with a dispersion medium, an organic binder, an inorganic binder, a surfactant, a pore former, and the like. The composition ratio of each raw material is not particularly limited, and is preferably a composition ratio in accordance with the structure and material of the honeycomb structure to be manufactured.

  Water can be used as the dispersion medium. It is preferable that the addition amount of a dispersion medium is 10-30 mass parts with respect to 100 mass parts of ceramic raw materials.

  The organic binder is preferably methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, or a combination thereof. Moreover, the addition amount of the organic binder is preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the ceramic raw material.

  As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type and may be used in combination of 2 or more type. The addition amount of the surfactant is preferably 0.5 to 2 parts by mass with respect to 100 parts by mass of the ceramic raw material.

  As the pore former, resin particles, starch, carbon and the like can be used. The pore former is for forming pores in the partition walls of the honeycomb structure to be manufactured. The amount of pore former added is preferably adjusted as appropriate in consideration of the average pore diameter and porosity of the partition walls of the honeycomb structure to be produced.

  There is no restriction | limiting in particular as a method of kneading | mixing a shaping | molding raw material and forming a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  Next, the obtained clay is formed to form a cylindrical honeycomb formed body. The honeycomb formed body has partition walls that form a plurality of cells and an outer peripheral wall. A method for forming a kneaded clay to form a honeycomb formed body is not particularly limited, and a known forming method such as extrusion molding or injection molding can be used. For example, a preferable example includes a method of extrusion molding using a die for extrusion molding having a desired cell shape, partition wall thickness, and cell density. As a material of the die for extrusion molding, a cemented carbide which does not easily wear is preferable. Note that the cell shape, partition wall thickness, cell density, and the like may be changed in the two honeycomb structures to be manufactured (that is, the first honeycomb structure and the second honeycomb structure).

  Next, the obtained honeycomb formed body is dried. Examples of the drying method include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, and the like. Among them, it is preferable to perform dielectric drying, microwave drying, or hot air drying alone or in combination.

  Next, the honeycomb formed body is fired. Prior to firing the honeycomb formed body, the honeycomb formed body is preferably calcined. Calcination is performed for degreasing. There is no restriction | limiting in particular about the method of calcination. For example, it is sufficient that at least a part of the organic matter in the honeycomb formed body can be removed. Examples of the organic material include an organic binder, a surfactant, and a pore former. The combustion temperature of the organic binder is about 100 to 300 ° C. For this reason, calcination is preferably performed at about 200 to 1000 ° C. for about 10 to 100 hours in an oxidizing atmosphere.

  The firing of the honeycomb formed body is performed in order to sinter and densify the forming raw material constituting the calcined formed body to ensure a predetermined strength. Since the firing conditions differ depending on the type of molding raw material, appropriate conditions may be selected according to the type. For example, when the cordierite forming raw material is used, the firing temperature is preferably 1350 to 1440 ° C. In addition, the firing time is preferably 3 to 10 hours as the keep time at the maximum temperature. Examples of the apparatus for performing calcination and main firing include an electric furnace and a gas furnace. Thus, a honeycomb structure can be obtained by calcining and firing the honeycomb formed body.

  As described above, the first honeycomb structure and the second honeycomb structure for the exhaust gas purification apparatus of the present embodiment can be manufactured.

  Moreover, the honeycomb structure (first honeycomb structure 4a) as shown in FIGS. 11 to 13 can be manufactured by the following method. First, a honeycomb structure is manufactured by the method described above. At this time, the honeycomb structure is manufactured such that the size of the outer peripheral shape is larger than the required size (that is, the size accommodated in the body portion of the can body). Next, the outer peripheral part of the obtained honeycomb structure is ground obliquely. That is, grinding is performed so that the honeycomb structure after grinding is formed into a slanted cylindrical shape. If necessary, both end faces of the honeycomb structure are ground so that the end faces are perpendicular to the side faces of the honeycomb structure after grinding. By performing the grinding process in this way, the honeycomb structure after the grinding process has the partition walls arranged so that the cell extending direction is inclined.

  Thereafter, a ceramic material is applied to the outer peripheral surface of the ground honeycomb structure to form an outer peripheral coat layer. This outer peripheral coat layer becomes the outer peripheral wall of the honeycomb structure. There is no particular limitation on the ceramic material applied to the outer peripheral surface of the ground honeycomb structure. For example, as a ceramic material for forming the outer peripheral coat layer, a ceramic material used for producing an outer peripheral wall in a conventionally known honeycomb structure can be suitably used.

  Next, a catalyst for purifying exhaust gas is supported on the partition walls of the obtained honeycomb structure. In this way, a honeycomb catalyst body is produced. There is no restriction | limiting in particular about the method to carry | support a catalyst, It can carry out according to a conventionally well-known method. In the exhaust gas purifying apparatus of the present embodiment, two honeycomb structures for the honeycomb catalyst body are produced in order to accommodate two honeycomb catalyst bodies inside the body portion of the can body. The two manufactured honeycomb structures become the first honeycomb structure and the second honeycomb structure. The type and amount of catalyst supported by the first honeycomb structure housed on the inlet side of the body portion of the can body and the second honeycomb structure body housed on the outlet side of the body portion of the can body May be changed.

  Next, a can for the exhaust gas purifying apparatus of the present embodiment is produced. The can body can be manufactured using a conventionally known metal processing method using stainless steel or the like. The can body includes a body portion that houses and holds the first honeycomb catalyst body and the second honeycomb catalyst body, an inflow port connected to the exit side of the engine exhaust manifold, and an outflow port through which the gas flowing in from the inflow port flows out. It is preferable to have it. The can body has a straight shape with a constant inner diameter of the body portion.

  Next, the first honeycomb catalyst body and the second honeycomb catalyst body are disposed inside the body portion of the can body. In this way, the exhaust gas purification apparatus of this embodiment can be manufactured. When the first honeycomb catalyst body and the second honeycomb catalyst body are disposed inside the body of the can body, the ceramic fiber mat is disposed around the outer peripheral surfaces of the first honeycomb catalyst body and the second honeycomb catalyst body. It is preferable to cover with a gripping material such as. The first honeycomb catalyst body and the second honeycomb catalyst body, the outer peripheral surfaces of which are covered with the gripping material, are arranged inside the body of the can body.

  When manufacturing the exhaust gas purifying apparatus of the present embodiment, the first honeycomb catalyst body and the second honeycomb catalyst body are arranged inside the body portion of the can body as follows. First, the first inflow end surface of the first honeycomb catalyst body is located on the inflow side of the can body, and the second outflow end surface of the second honeycomb catalyst body is located on the outflow side of the can body. A honeycomb catalyst body and a second honeycomb catalyst body are disposed. Further, the first honeycomb catalyst body and the second honeycomb catalyst body are arranged so that the distance from the first outflow end face of the first honeycomb catalyst body to the second inflow end face of the second honeycomb catalyst body is 50 mm or less. Further, the first honeycomb catalyst body and the second honeycomb are formed so that the angle formed by the extending direction of the first cell of the first honeycomb catalyst body and the extending direction of the second cell of the second honeycomb catalyst body is 2 to 15 °. A catalyst body is disposed. As described above, the exhaust gas purification apparatus of the present embodiment can be manufactured. The angle adjustment of the extending direction of the 1st cell of a 1st honeycomb catalyst body and the extending direction of the 2nd cell of a 2nd honeycomb catalyst body can be adjusted with the thickness of the holding material mentioned above, for example.

  Hereinafter, the exhaust gas purifying apparatus of the present invention will be described more specifically with reference to examples. The present invention is not limited in any way by these examples.

Example 1
[Production of first honeycomb catalyst body]
A first honeycomb catalyst body used in the exhaust gas purification apparatus of Example 1 was produced. Specifically, first, a kneaded material for forming a honeycomb formed body was prepared using a forming raw material containing a ceramic raw material. As a ceramic raw material, a cordierite forming raw material was used. A clay for molding was prepared by adding a dispersion medium, an organic binder, a dispersant and a pore former to the cordierite forming raw material. The addition amount of the dispersion medium was 30 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The addition amount of the organic binder was 6 parts by mass with respect to 100 parts by mass of the cordierite forming raw material. The addition amount of the pore former was 1 part by mass with respect to 100 parts by mass of the cordierite forming raw material. The obtained ceramic forming raw material was kneaded using a kneader to obtain clay.

  Next, the obtained kneaded material was extruded using a vacuum extrusion molding machine to obtain a honeycomb formed body. Next, the honeycomb formed body was dried by high frequency dielectric heating and then dried at 120 ° C. for 2 hours using a hot air dryer. Then, it fired at 1350-1450 degreeC for 10 hours, and obtained the 1st honeycomb structure.

  A catalyst was supported on the first partition walls of the obtained first honeycomb structure. The catalyst contains platinum (Pt), rhodium (Rh), palladium (Pd) in a mass ratio of 1: 0.5: 4 (Pt: Rh: Pd), and mainly contains alumina and ceria. Was used. The amount of catalyst supported was 150 g / L. The catalyst loading (g / L) is the amount (g) of the catalyst supported per unit volume (1 L) of the first honeycomb structure.

The first honeycomb catalyst body produced in Example 1 had a cylindrical shape with a length (total length) in the cell extending direction of 120 mm and an outer diameter of the inflow end surface and the outflow end surface of 114 mm. The partition wall thickness was 0.1 mm. The shape of each cell in the cross section perpendicular to the cell extending direction was a square, and the cell density was 62 cells / cm ² . Further, the porosity of the first partition walls of this first honeycomb structure was 35%, and the average pore diameter of the first partition walls was 4 μm. The porosity and average pore diameter are values measured by “Autopore III 9420 (trade name)” manufactured by Micromeritics.

[Production of second honeycomb catalyst body]
A second honeycomb structure for the second honeycomb catalyst body was produced in the same manner as described for the first honeycomb catalyst body.

  A catalyst was supported on the second partition walls of the obtained second honeycomb structure. The catalyst contains platinum (Pt), rhodium (Rh), palladium (Pd) in a mass ratio of 1: 0.5: 4 (Pt: Rh: Pd), and mainly contains alumina and ceria. Was used. The amount of catalyst supported was 150 g / L.

The second honeycomb catalyst body produced in Example 1 had a cylindrical shape in which the length (full length) in the cell extending direction was 120 mm, and the outer diameter of the inflow end surface and the outflow end surface was 114 mm. The partition wall thickness was 0.1 mm. The shape of each cell in the cross section perpendicular to the cell extending direction was a square, and the cell density was 93 cells / cm ² . Further, the porosity of the second partition walls of this second honeycomb structure was 35%, and the average pore diameter of the second partition walls was 4 μm.

[Manufacture of exhaust gas purification equipment]
The first honeycomb catalyst body and the second honeycomb catalyst body manufactured in Example 1 were accommodated in a can body having an inlet, a trunk, and an outlet through a ceramic fiber non-thermally expandable mat. . And the expanded pipe part and the narrow pipe part were formed by spinning process, and the exhaust gas purification apparatus of Example 1 was manufactured.

  Inside the body of the can body, the first inflow end surface of the first honeycomb catalyst body is located on the inflow side of the can body, and the second outflow end surface of the second honeycomb catalyst body is on the outflow side of the can body The first honeycomb catalyst body and the second honeycomb catalyst body were disposed so as to be positioned at each other. Further, the first cell in the first honeycomb catalyst body was arranged so that the angle formed by the extending direction P1 of the first cell and the extending direction P2 of the second honeycomb catalyst body in the second cell was 2 °. “An angle formed by the extending direction P1 of the first cell of the first honeycomb catalyst body and the extending direction P2 of the second cell of the second honeycomb catalyst body” is expressed as “the extending direction of the first cell and the second cell It is shown in the column of “Angle (°) with the extending direction”.

  The distance t from the first outflow end face of the first honeycomb catalyst body to the second inflow end face of the second honeycomb catalyst body was 2 mm. The “interval from the first outflow end surface of the first honeycomb catalyst body to the second inflow end surface of the second honeycomb catalyst body” is shown in the “interval t (mm)” column of Table 1. The distance t from the first outflow end surface of the first honeycomb catalyst body to the second inflow end surface of the second honeycomb catalyst body is from the first outflow end surface to the second inflow end surface at the opposing first outflow end surface and second inflow end surface. The shortest distance.

  Further, in Example 1, the first honeycomb catalyst body and the second honeycomb catalyst body were disposed inside the trunk portion of the can body as follows. The first honeycomb catalyst body was arranged so that the direction P1 in which the first cell extends was inclined with respect to the flow direction P3 of the gas flowing in from the inlet of the can body. Further, the second honeycomb catalyst body was arranged so that the direction P2 in which the second cell extends was parallel to the flow direction P3 of the gas flowing in from the inlet of the can body. In the present embodiment, an arrangement in which the first cell extending direction P1 is inclined and the second cell extending direction P2 is parallel to the gas flow direction P3 is referred to as “arrangement A”. In Table 1, the “arrangement of the first honeycomb catalyst body and the second honeycomb catalyst body” column shows the arrangement of the first honeycomb catalyst body and the second honeycomb catalyst body.

  Further, in this example, the arrangement of the first honeycomb catalyst body and the second honeycomb catalyst body is the following case as “Arrangement B”. That is, the first honeycomb catalyst body is arranged so that the direction P1 in which the first cell extends is parallel to the flow direction P3 of the gas flowing in from the inlet of the can body, and the flow direction P3 of the gas Thus, the second honeycomb catalyst body is disposed so that the extending direction P2 of the second cell is inclined. Moreover, the arrangement | positioning of the 1st honeycomb catalyst body and the 2nd honeycomb catalyst body is the following cases, and is set as "arrangement C". That is, the first honeycomb catalyst body is disposed so that the direction P1 in which the first cell extends is inclined with respect to the gas flow direction P3 flowing from the inlet of the can body, and the gas flow direction P3 is The second honeycomb catalyst body is disposed so that the extending direction P2 of the second cell is inclined. Furthermore, the arrangement | positioning of a 1st honeycomb catalyst body and a 2nd honeycomb catalyst body is the following case, and is set as "arrangement D." That is, the first honeycomb catalyst body and the second honeycomb catalyst body are arranged so that the direction P1 of the first cell and the direction P2 of the second cell extend in parallel to the flow direction P3 of the gas flowing from the inlet of the can body. A honeycomb catalyst body is disposed.

(Examples 2 to 23, Comparative Examples 1 to 7)
“Angle (°) between the extending direction of the first cell and the extending direction of the second cell”, “the interval t (mm)”, and “the arrangement of the first honeycomb catalyst body and the second honeycomb catalyst body” are shown in Table 1. Exhaust gas purification apparatus was produced by the same method as Example 1 except having changed as shown. That is, the configurations of the first honeycomb catalyst body, the second honeycomb catalyst body, and the can body are the same as those in Example 1, and the arrangement (that is, the inclination and the interval) between the first honeycomb catalyst body and the second honeycomb catalyst body is changed. An exhaust gas purification device was produced by changing. In the case of “arrangement C”, the angle β formed by the flow direction P3 of the gas G0 flowing from the inlet 52 of the can body 50 and the direction P1 in which the first cell 2 extends is determined by the first honeycomb catalyst body. The first cell extending direction P1 and the second honeycomb catalyst body extending in the second cell extending direction P2 were arranged to be ½ of the angle.

(Comparative example 8 (exhaust gas purification device as a reference for evaluation))
“Angle (°) between the extending direction of the first cell and the extending direction of the second cell”, “the interval t (mm)”, and “the arrangement of the first honeycomb catalyst body and the second honeycomb catalyst body” are shown in Table 1. Exhaust gas purification apparatus was produced by the same method as Example 1 except having changed as shown. That is, in Comparative Example 8, the configurations of the first honeycomb catalyst body, the second honeycomb catalyst body, and the can body are the same as those in Example 1, and the first honeycomb catalyst body and the second honeycomb catalyst body are separated from each other. The exhaust gas purification apparatus was manufactured by arranging in series such that the cell extending direction was parallel to the gas flow direction P3. In Comparative Example 8, a plurality of exhaust gas purifying apparatuses were manufactured so as to have the same interval as “Interval t” in Examples 1 to 23 and Comparative Examples 1 to 7. The exhaust gas purifying apparatus of Comparative Example 8 is an exhaust gas purifying apparatus that becomes an evaluation standard in the following “evaluation of increase in pressure loss” and “evaluation of purification performance”. That is, when evaluating the exhaust gas purifying apparatuses of Examples 1 to 23 and Comparative Examples 1 to 7, the exhaust gas purifying apparatus of Comparative Example 8 in which the “interval t” is the same value becomes the reference for the evaluation. .

  With respect to the exhaust gas purification apparatuses of Examples 1 to 23 and Comparative Examples 1 to 7, “pressure loss increase evaluation” and “purification performance evaluation” were performed by the following methods. The evaluation results are shown in Table 1.

[Evaluation of pressure loss rise]
Using an engine dynamo device in which a 2.0 L gasoline engine was installed, an increase in pressure loss of the exhaust gas purifying devices of Examples 1 to 23 and Comparative Examples 1 to 8 was evaluated. Specifically, an exhaust gas purification device was installed on the outlet side of the engine exhaust manifold of a 2.0 L gasoline engine, and the pressure loss was measured at an engine speed of 5500 rpm and full throttle (WOT: Wide-Open Throttle). . The pressure loss of the exhaust gas purifying apparatuses of Examples 1 to 23 and Comparative Examples 1 to 7 and the pressure loss of the exhaust gas purifying apparatus of Comparative Example 8 having the same “interval t” are evaluated as follows. Evaluation was made by reference.
A: When the pressure loss of the exhaust gas purifying apparatus of the reference comparative example 8 is 100%, the pressure loss of the exhaust gas purifying apparatus to be evaluated is 102% or less.
B: When the pressure loss of the exhaust gas purifying apparatus of the reference comparative example 8 is 100%, the pressure loss of the exhaust gas purifying apparatus to be evaluated exceeds 102% and is 104% or less.
C: When the pressure loss of the exhaust gas purifying apparatus of the reference comparative example 8 is 100%, the pressure loss of the exhaust gas purifying apparatus to be evaluated exceeds 104% and is 106% or less.
D: When the pressure loss of the exhaust gas purification apparatus of the reference comparative example 8 is 100%, the pressure loss of the exhaust gas purification apparatus to be evaluated exceeds 106%.

  In addition, in the increase evaluation of the pressure loss, in the case of “A”, the influence on the engine performance can be ignored, and it can be said that it is particularly favorable. In the case of “B”, the influence on the engine performance is at a level where there is not much problem in practical use, which can be said to be better. In the case of “C”, the influence on the engine performance is at a level that does not cause a large problem in practical use, and it can be said that it is favorable. In the case of “D”, the engine performance is affected and it can be said that it is defective.

[Evaluation of purification performance]
A 2.0 L gasoline engine vehicle was run on the chassis dynamo, and the purification performance of the exhaust gas purification apparatuses of Examples 1 to 23 and Comparative Examples 1 to 8 was evaluated. Specifically, a 2.0-liter gasoline engine vehicle is operated in the European NEDC mode, and hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NO _x ) in the exhaust gas while traveling in the European NEDC mode. Discharge amount (unit: g / km) was measured. About the exhaust gas purification apparatus of Examples 1-23 and Comparative Examples 1-7, it evaluated by the following evaluation criteria of A-D on the basis of the exhaust gas purification apparatus of the comparative example 8 from which "interval t" becomes the same value. . In the following evaluation criteria, HC emission amount of the exhaust gas purifying apparatus of the reference comparative example 8, CO emissions, for NO _X emissions, HC emissions of the exhaust gas purifying apparatus to be evaluated, CO emissions, NO _X emissions Evaluation will be made based on the ratio (percentage). Hereinafter, HC emission amount of the exhaust gas purifying apparatus to be evaluated, CO emissions, and are collectively referred to NO _X emissions the ratio (percentage) is sometimes referred to as "emission ratio".
A: HC emissions of the exhaust gas purifying apparatus to be evaluated, CO emissions, and of the emission ratio of the NO _X emissions, a large emission amount ratio of most value, or less 93%.
B: HC emissions of the exhaust gas purifying apparatus to be evaluated, CO emissions, and of the emission ratio of the NO _X emissions, a large emission amount ratio of most value, greater than 93%, and 96% or less.
C: HC emissions of the exhaust gas purifying apparatus to be evaluated, CO emissions, and of the emission ratio of the NO _X emissions, a large emission amount ratio of most value, greater than 96%, is 99% or less.
D: HC emissions of the exhaust gas purifying apparatus to be evaluated, CO emissions, and of the emission ratio of the NO _X emissions, a large emission amount ratio of most value, greater than 99%. The HC emission amount, CO emission amount, and NO _X emission amount of the exhaust gas purification device to be evaluated exceed the HC emission amount, CO emission amount, and NO _X emission amount of the exhaust gas purification device of the reference comparative example 8 (that is, the emission amount). It also includes the case where the ratio exceeds 100%.

  In the evaluation of the purification performance, in the case of “A”, it can be said that the purification performance is particularly good. In the case of “B”, it can be said that the purification performance is better. In the case of “C”, it can be said that the purification performance is good. In the case of “D”, it can be said that the purification performance is substantially unchanged or deteriorated.

(result)
As shown in Table 1, the exhaust gas purification apparatuses of Examples 1 to 23 were able to obtain good results both in the evaluation of increase in pressure loss and the evaluation of purification performance. In particular, in the exhaust gas purification apparatuses of Examples 4 to 11 and 13, the evaluation of the increase in pressure loss and the evaluation of the purification performance were both “A”, and particularly good results could be obtained. In the exhaust gas purification apparatuses of Examples 1 to 3, since the “angle (°) between the extending direction of the first cell and the extending direction of the second cell” was small, the purification performance was slightly improved. In the exhaust gas purification apparatuses of Examples 12, 17 and 18, since the “interval t (mm)” was wide, the increase in pressure loss was relatively large and the purification performance was slightly improved. In the exhaust gas purification apparatuses of Examples 14 to 16, the “angle formed between the extending direction of the first cell and the extending direction of the second cell (°)” was large, so that the increase in pressure loss was relatively large. However, the exhaust gas purification apparatuses of Examples 14 to 16 were particularly good in evaluating the purification performance. In the exhaust gas purifying apparatuses of Examples 19 to 23, since the “angle between the extending direction of the first cell and the extending direction of the second cell (°)” is larger, the increase in pressure loss is relatively large. The improvement in purification performance was also slightly lower.

  On the other hand, in the exhaust gas purification apparatuses of Comparative Examples 1 to 7, the evaluation of the purification performance was all “D”, and the purification performance was substantially unchanged or deteriorated. The exhaust gas purifying apparatuses of Comparative Examples 1 and 2 had the result that the purification performance was hardly improved because the “angle (°) between the extending direction of the first cell and the extending direction of the second cell” was extremely small. In the exhaust gas purifying apparatuses of Comparative Examples 3 and 4, the “interval t (mm)” is very wide, so that the pressure loss is greatly increased. As a result, the purification performance is also deteriorated. In the exhaust gas purification apparatuses of Comparative Examples 5 and 6, the “angle between the direction in which the first cell extends and the direction in which the second cell extends (°)” is very large, so that the pressure loss greatly increases. The performance also deteriorated.

  The exhaust gas purification apparatus of the present invention can be used for purification of exhaust gas discharged from an internal combustion engine. In particular, it can be suitably used for purifying exhaust gas discharged from a gasoline engine.

1, 1a: first partition wall, 2, 2a: first cell, 3, 3a: first outer peripheral wall, 4, 4a: first honeycomb structure, 7: first catalyst, 10, 10a: first honeycomb catalyst body 11, 11a: first inflow end surface, 12, 12a: first outflow end surface, 21: second partition wall, 22: second cell, 23: second outer peripheral wall, 24: second honeycomb structure, 27: second Catalyst: 30: Second honeycomb catalyst body, 31: Second inflow end face, 32: Second outflow end face, 50: Can body, 51: Body part, 52: Inlet, 53: Outlet, 55a, 55b: Gripping material , 100, 101, 102, 103: exhaust gas purification device, G0, G1, G2, G3: gas, P1: direction in which the first cell extends, P2: direction in which the second cell extends, P3: inflow from the inlet of the can body Gas flow direction, α: angle (the direction in which the first cell of the first honeycomb catalyst body 10 extends) The angle between the direction of extension of the second cell of the two honeycomb catalyst body).

Claims (6)

A first honeycomb catalyst body, a second honeycomb catalyst body, and a cylindrical can body in which the first honeycomb catalyst body and the second honeycomb catalyst body are housed,
The first honeycomb catalyst body has a cylindrical shape having a porous first partition wall defining a plurality of first cells extending from a first inflow end surface to a first outflow end surface, and a first outer peripheral wall disposed at the outermost periphery. A first honeycomb structure, and a first catalyst supported on the first partition wall of the first honeycomb structure,
The second honeycomb catalyst body has a cylindrical shape having a porous second partition wall defining a plurality of second cells extending from the second inflow end surface to the second outflow end surface and a second outer peripheral wall disposed at the outermost periphery. A second honeycomb structure, and a second catalyst supported on the second partition wall of the second honeycomb structure,
The can body flows out an inflow port connected to an outlet side of an engine exhaust manifold, a body portion in which the first honeycomb catalyst body and the second honeycomb catalyst body are housed, and a gas flowing in from the inflow port. An outlet, and
The trunk part of the can body has a straight shape with a constant inner diameter of the trunk part,
Inside the trunk portion, the first honeycomb catalyst body and the second honeycomb catalyst body, the first inflow end surface of the first honeycomb catalyst body is located on the inlet side of the can body, The second outflow end surface of the second honeycomb catalyst body is located on the outflow side of the can body, the second outflow end surface of the second honeycomb catalyst body from the first outflow end surface of the first honeycomb catalyst body. And the angle formed between the extending direction of the first cell of the first honeycomb catalyst body and the extending direction of the second cell of the second honeycomb catalyst body is 2 to 15 °. An exhaust gas purifying device arranged as described above.   The extending direction of the first cell of the first honeycomb catalyst body is inclined with respect to the flow direction of the gas flowing in from the inlet of the can body, and the extending direction of the second cell of the second honeycomb catalyst body The exhaust gas purification apparatus according to claim 1, wherein the first honeycomb catalyst body and the second honeycomb catalyst body are arranged inside the body portion so that the two are parallel to each other.   The extending direction of the first cell of the first honeycomb catalyst body is parallel to the flow direction of the gas flowing in from the inlet of the can body, and the second cell of the second honeycomb catalyst body extends. The exhaust gas purification apparatus according to claim 1, wherein the first honeycomb catalyst body and the second honeycomb catalyst body are arranged inside the body portion so that the direction is inclined.   A direction in which the first cell extends in the first honeycomb catalyst body and a direction in which the second cell extends in the second honeycomb catalyst body with respect to the flow direction of the gas flowing in from the inlet of the can body. The exhaust gas purifying apparatus according to claim 1, wherein the first honeycomb catalyst body and the second honeycomb catalyst body are arranged inside the trunk portion so as to be inclined.   The first partition wall of the first honeycomb catalyst body is arranged such that a direction in which the first cell extends is inclined with respect to a direction in which the first outer peripheral wall formed in a cylindrical shape extends. The exhaust gas purification apparatus according to any one of 1 to 4.   The second partition wall is configured such that the second partition wall is disposed so that the extending direction of the second cell is inclined with respect to the extending direction of the second outer peripheral wall formed in a cylindrical shape. The exhaust gas purification apparatus according to any one of 1 to 5.

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