Honeycomb carrier and exhaust gas purification method

Abstract

A honeycomb body comprised of corrugated sheet and flat sheet, depending on the joined position of the honeycomb body and jacket, is liable to be damaged at the joined part resulting in the honeycomb body detaching and dropping out from the jacket. A honeycomb carrier 10, wherein the honeycomb carrier has a honeycomb body 110 comprised of a metallic corrugated sheet and a metallic flat sheet wound superposed and a jacket 120 housing that honeycomb body 110, the corrugated sheet and the flat sheet are fastened with each other by brazing at a first brazing fastening region 111 of a gas outflow side end part 110b of the honeycomb body, the honeycomb body 110 and the jacket 120 are fastened with each other by brazing at a second brazing fastening region 121 of the gas outflow side end part 110b of the honeycomb body, and an axial direction length of the first brazing fastening region 111 is 1.2 times or less an axial direction length of the second brazing fastening region 121. Optionally, there is a third brazing fastening region 112 at the gas inflow side end part 110a.

Description

HONEYCOMB CARRIER AND EXHAUST GAS PURIFICATION METHOD

[0001] The present invention relates to a honeycomb carrier and an exhaust gas purification method.

[0002] Honeycomb carriers using metallic base materials are being widely used as exhaust gas purification catalysts of internal combustion engines for motorcycle use, power generator use, farm machinery, etc. Honeycomb carriers comprise honeycomb bodies and jackets housing and fastened with the same by brazing. Honeycomb bodies generally are wound up bodies of laminates of corrugated sheets (metal foil worked into corrugated shapes) and flat sheets (flat metal foil). As honeycomb carriers, the following such ones are known.

[0003] For example, PTL 1 discloses a honeycomb body provided with two facing end faces and including at least one housing and at least one metal layer forming passages. In the honeycomb body, at least one of the end faces has at least one hard brazing section. That section forms a nonbrazing region contacting and circling the housing in a belt-like manner. In only at least one partial region a distance away from the end face, a hard brazing joined part is provided between the at least one layer and the at least one housing. According to the honeycomb carrier of PTL 1, even if the ratio of the diameter / length is not preferable, it is possible to provide a honeycomb body or produce a honeycomb body guaranteeing a good joined part of one metal layer or several metal layers with the housing. Simultaneously, the honeycomb body has excellent ability to compensate for different heat expansion behaviors of component elements of the honeycomb body and can give high strength or flexibility with respect to a dynamic alternating load due to heat.

[0004] PTL 2 discloses a metal honeycomb carrier obtained by laminating a metallic corrugated sheet and a flat sheet and winding these etc. up in multiple layers to form a core part and housing that core inside a jacket. In the metal honeycomb carrier, the corrugated sheet and flat sheet are joined together at one or more cross-sections of the core part. The outer circumference of the core part is joined with the inner surface of the jacket at only one cross-section of the jacket. According to the metal honeycomb carrier of PTL 2, since the outer circumference of the core part is joined with the inner surface of the jacket only at one cross-section of the jacket, even if a difference arises in thermal expansion of the core part and the jacket, the core part can freely expand toward the free end side about the joined part with the jacket. Therefore, it is considered possible to effectively prevent separation of the joined part of the core part and jacket due to a heat cycle.

[0005] Japanese Unexamined Patent Publication No. 2009-508681Japanese Unexamined Utility Model Publication No. 62-194436

[0006] A honeycomb body comprised of corrugated sheet and flat sheet, depending on the joined position of the honeycomb body and jacket, is liable to be damaged at the joined part resulting in the honeycomb body detaching and dropping out from the jacket.

[0007] Therefore, the present invention has as its object the provision of a honeycomb carrier able to suppress separation of the honeycomb body and jacket.

[0008] The present invention achieves the above object by the following means:

[0009] <Aspect 1> A honeycomb carrier, wherein the honeycomb carrier has a honeycomb body comprised of a metallic corrugated sheet and a metallic flat sheet wound superposed and a jacket housing that honeycomb body, the corrugated sheet and the flat sheet are fastened with each other by brazing at a first brazing fastening region of a gas outflow side end part of the honeycomb body, the honeycomb body and the jacket are fastened with each other by brazing at a second brazing fastening region of the gas outflow side end part of the honeycomb body, and an axial direction length of the first brazing fastening region is 1.2 times or less an axial direction length of the second brazing fastening region. <Aspect 2> The honeycomb carrier according to the aspect 1, wherein the axial direction length of the first brazing fastening region is 0.8 time or more and 1.2 times or less of the axial direction length of the second brazing fastening region. <Aspect 3> The honeycomb carrier according to the aspect 1 or 2, wherein the corrugated sheet and the flat sheet are fastened together by brazing at a third brazing fastening region of a gas inflow side end part of the honeycomb body. <Aspect 4> The honeycomb carrier according to any one of the aspects 1 to 3, wherein the honeycomb body has a diametrical direction inside circumference region and diametrical direction outside circumference region, and the third brazing fastening region is arranged only at the diametrical direction inside circumference region among the diametrical direction inside circumference region and the diametrical direction outside circumference region. <Aspect 5> The honeycomb carrier according to any one of the aspects 1 to 4, wherein at least one of the corrugated sheet and the flat sheet has an aperture region at a center in the axial direction of the honeycomb body and an aperture-free region at an upstream side end in the axial direction of the honeycomb body, and an axial direction length of the aperture-free region at the upstream side end is longer than the axial direction length of the third brazing fastening region. <Aspect 6> The honeycomb carrier according to any one of the aspects 1 to 5, wherein at least one of the corrugated sheet and flat sheet has apertures, and an axial direction end part of the third brazing fastening region is superposed over the apertures of only one of the corrugated sheet or the flat sheet or is not superposed over the apertures of any of the corrugated sheet or the flat sheet. <Aspect 7> An exhaust gas purification method, comprising making exhaust gas following through a honeycomb carrier according to any one of the aspects 1 to 6 so as to purify the exhaust gas.

[0010] According to the honeycomb carrier of the present invention, it is possible to keep a honeycomb body and a jacket from separating.

[0011] FIG. 1 is a schematic view for explaining a honeycomb carrier of the present invention.FIG. 2 is a schematic view of a cross-section for explaining the honeycomb carrier of the present invention.FIG. 3 is a schematic view of a cross-section for explaining the honeycomb carrier of the present invention where a third brazing fastening region is provided.FIGS. 4A and 4B are schematic views seen from a gas inflow side for explaining the honeycomb carrier of the present invention.FIGS. 4A and 4B are schematic views seen from a gas inflow side for explaining the honeycomb carrier of the present invention.FIGS. 5A and 5B are schematic views for explaining a metallic corrugated sheet and flat sheet forming the honeycomb body of the honeycomb carrier of the present invention.FIGS. 5A and 5B are schematic views for explaining a metallic corrugated sheet and flat sheet forming the honeycomb body of the honeycomb carrier of the present invention.FIG. 6 is a schematic view for explaining the honeycomb carrier of the present invention in which a honeycomb body comprised of a corrugated sheet and flat sheet having apertures is provided.FIGS. 7A and 7B are schematic views for explaining the honeycomb carrier of the present invention in which a honeycomb body comprised of a corrugated sheet and flat sheet having apertures is provided.FIGS. 7A and 7B are schematic views for explaining the honeycomb carrier of the present invention in which a honeycomb body comprised of a corrugated sheet and flat sheet having apertures is provided.

[0012] Below, embodiments of the present invention will be explained in detail. Note that the present invention is not limited to the following embodiments and can be modified in various ways within the scope of the gist of the present invention. Further, in the explanation of the drawings, the same elements are assigned the same reference notations and overlapping explanations will be omitted.

[0013] <<Honeycomb Carrier>> In the honeycomb carrier of the present invention, the honeycomb carrier has a honeycomb body comprised of a metallic corrugated sheet and a flat sheet wound superposed and a jacket housing that honeycomb body, the corrugated sheet and the flat sheet are fastened with each other by brazing at a first brazing fastening region of a gas outflow side end part of the honeycomb body, the honeycomb body and the jacket are fastened with each other by brazing at a second brazing fastening region of the gas outflow side end part of the honeycomb body, and an axial direction length of the first brazing fastening region is 1.2 times or less an axial direction length of the second brazing fastening region.

[0014] According to the honeycomb carrier of the present invention, it is possible to keep the honeycomb body and jacket from separating.

[0015] Specifically, for example, as shown in FIG. 2, the honeycomb carrier 10 of the present invention has a honeycomb body 110 comprised of a metallic corrugated sheet and a flat sheet wound superposed and a jacket 120 housing that honeycomb body. Further, the corrugated sheet and the flat sheet forming the honeycomb body are fastened with each other by brazing at a first brazing fastening region 111 of a gas outflow side end part 110b of the honeycomb body, and the honeycomb body 110 and the jacket 120 are fastened with each other by brazing at a second brazing fastening region 121 of the gas outflow side end part 10b of the honeycomb body. Further, an axial direction length of the first brazing fastening region 111a is 1.2 times or less an axial direction length of the second brazing fastening region 121a.

[0016] Since the second brazing fastening region 121 is arranged at the gas outflow side end part 10b, it is possible to keep cracks from forming due to a heat load etc. of the brazing material fastening the honeycomb body and jacket at the second brazing fastening region 121 and thereby keep the honeycomb body 110 and jacket 120 from separating.

[0017] Furthermore, since the first brazing fastening region 111 fastening the corrugated sheet and flat sheet of the honeycomb body 110 is positioned inside of the second brazing fastening region 121 fastening the honeycomb body and jacket, it is possible to strongly fasten the honeycomb body and jacket at the second brazing fastening region 121 and thereby possible to keep the honeycomb body 110 and jacket 120 from separating.

[0018] <Configuration of Honeycomb Carrier> The honeycomb carrier has a honeycomb body comprised of a metallic corrugated sheet and a flat sheet wound superposed and a jacket housing that honeycomb body.

[0019] (Corrugated Sheet and Flat Sheet) The corrugated sheet and flat sheet are not particularly limited, but may respectively be ones having apertures or may be ones not having apertures. The metallic corrugated sheet and flat sheet forming the honeycomb body preferably have apertures from the viewpoint of improving the purification efficiency of exhaust gas.

[0020] The apertures of the corrugated sheet and flat sheet are not particularly limited, but the apertures may all be the same size or may be different sizes. The apertures of the metallic flat sheet are preferably larger than the apertures of the metallic corrugated sheet from the viewpoint of improving the purification efficiency of exhaust gas.

[0021] All or some of the apertures of the corrugated sheet may be circular or elliptical and may also be aspherical, for example, polygonal. The equivalent diameters of the apertures of the corrugated sheet may be 2.0 mm or more, 2.5 mm or more, 3.0 mm or more, 4.0 mm or more, 5.0 mm or more, or 7.0 mm or more and may be 20 mm or less, 15 mm or less, 10 mm or less, 7.0 mm or less, 5.0 mm or less, or 4.0 mm or less. Note that, “equivalent diameter” means the diameter of a true circle having an outer circumference length equal to the outer circumferential length of its faces.

[0022] All or some of the apertures of the flat sheet may be circular or elliptical and may also be aspherical, for example, polygonal. The equivalent diameters of the apertures of the flat sheet may be 3.0 mm or more, 3.5 mm or more, 5.0 mm or more, 8.0 mm or more, 10 mm or more, or 12 mm or more and may be 25 mm or less, 20 mm or less, 15 mm or less, 10 mm or less, 7.0 mm or less, or 5.0 mm or less.

[0023] The pitch of the adjoining apertures in the axial direction of the tubular honeycomb body (distance between centers of adjoining apertures) may be, respectively in the apertures of the corrugated sheet and flat sheet, 5.0 mm or more, 6.0 mm or more, 8.0 mm or more, 10 mm or more, 12 mm or more, or 15 mm or more and may be 25 mm or less, 20 mm or less, 15 mm or less, 10 mm or less, 7.0 mm or less, or 5.0 mm or less. Note that, in this case, the aperture pitch of the corrugated sheet means the pitch in the case of stretching out the corrugated sheet flat.

[0024] The pitch of the adjoining apertures in the circumferential direction of the tubular honeycomb body may be, respectively in the apertures of the corrugated sheet and flat sheet, 5.0 mm or more, 6.0 mm or more, 8.0 mm or more, 10 mm or more, 12 mm or more, or 15 mm or more and may be 35 mm or less, 25 mm or less, 20 mm or less, 15 mm or less, 10 mm or less, 7.0 mm or less, or 5.0 mm or less. Note that, in this case, the aperture pitch of the corrugated sheet means the pitch in the case of stretching out the corrugated sheet flat.

[0025] The aperture ratios of the corrugated sheet and flat sheet may respectively be 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, or 60% or more and may be 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, or 30% or less.

[0026] The apertures of the corrugated sheet and flat sheet may be equally present over the entire circumferential direction and axial direction of the tubular honeycomb body or may be unevenly present at some locations. For example, the apertures of the corrugated sheet and flat sheet need not be present at the end parts.

[0027] The apertures of the corrugated sheet and flat sheet are not particularly limited, but can be formed by using a punching machine etc. to punch the metal foils so as to give the desired aperture ratios. Note that, the shapes of the apertures are not particularly limited.

[0028] The shape of the corrugated sheet is not particularly limited, but may be a wavy shape or may be an omega wave shape or zigzag shape.

[0029] The thicknesses of the corrugated sheet and flat sheet are not particularly limited, but may be, respectively, 20 μm or more, 40 μm or more, 80 μm or more, or 100 μm or more and may be 500 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, or 80 μm or less.

[0030] FIG. 1 is a schematic view showing one aspect of the honeycomb carrier of the present invention, but the invention is not limited to this case.

[0031] The honeycomb body 110 comprised of the metallic corrugated sheet and flat sheet wound superposed is housed in the jacket 120 to form the honeycomb carrier 10. The honeycomb body is not particularly limited, but may be comprised of one laminate or several laminates of the corrugated sheet and flat sheet wound together to form a tubular body.

[0032] <First Brazing Fastening Region and Second Brazing Fastening Region > In the honeycomb carrier of the present invention, the corrugated sheet and the flat sheet are fastened together by brazing at the first brazing fastening region of the gas outflow side end part of the honeycomb body, and the honeycomb body and jacket are fastened together by brazing at the second brazing fastening region of the gas outflow side end part of the honeycomb carrier.

[0033] The honeycomb carrier and honeycomb body have gas inflow side end parts and gas outflow side end parts. The honeycomb carrier is not particularly limited, but can be used to make gas etc. circulate through the inside of the honeycomb carrier.

[0034] The brazing is not particularly limited, but, for example, a brazing filler metal can be heated to a 450℃ or more temperature to render it a liquid state, then the brazing filler metal may be cooled to make it solidify and thereby fasten an object. As the material of the brazing filler metal, for example, a nickel brazing filler, silver brazing filler, copper / brass brazing filler, phosphor copper brazing filler, or aluminum brazing filler can be used, but the invention is not limited to these cases.

[0035] As one example of the process of production of the honeycomb carrier of the present invention, a corrugated sheet and flat sheet are wound superposed to form a honeycomb body. Next, at an end part of the honeycomb body comprised of the corrugated sheet and flat sheet wound together, thickness 20 μm to 30 μm brazing filler metal foil is wound. Next, a cross-sectional C-shaped jacket of a cylinder having an equal length in the axial direction and a substantially equal length in the diametrical direction as the honeycomb body and formed with a slit in its side surface is prepared. Next, the honeycomb body with the brazing filler metal foil wrapped around it is inserted into the jacket, then the slit is welded shut. After that, the end face of the honeycomb body is dipped in a slurry containing brazing filler metal powder to place the brazing filler metal at the first brazing fastening region. Finally, a heater etc. is used to heat and cool the body to fasten the brazing filler metal at the first brazing fastening region and second brazing fastening region to thereby produce the honeycomb carrier.

[0036] As another example of the process of production of the honeycomb carrier of the present invention, a corrugated sheet and flat sheet are wound superposed to form a honeycomb body. Next, a jacket of a cylindrical shape having an equal length in the axial direction as the honeycomb body is prepared. Further, the previously formed honeycomb carrier is press-fit into the jacket. After that, the honeycomb body press fit into the jacket is dipped in a slurry containing brazing filler metal powder to enable the corrugated sheet and flat sheet to be fastened and the honeycomb body and jacket to be fastened at the first brazing fastening region and the second brazing fastening region.

[0037] Note that, in the first brazing fastening region, in addition to the method of dipping in a slurry containing brazing filler metal powder, a brazing filler metal powder is used and a tackifier is coated on the parts corresponding to the end part of the honeycomb body before winding up the corrugated sheet and flat sheet to deposit the brazing filler metal powder. After that, it is also possible to form the honeycomb body, then heat and braze it. Further, it is also possible to use a paste comprising a tackifier plus a brazing filler metal.

[0038] The honeycomb carrier of the present invention may also have a length in the axial direction of the jacket longer than the length in the axial direction of the honeycomb body. At this time, the second brazing fastening region may be formed at the further downstream side from the downstream end of the first brazing fastening region, but preferably it is formed at only the upstream side.

[0039] The amount of coating of the brazing filler metal at the first brazing fastening region is not particularly limited, but may be 1 g / L or more, 2 g / L or more, 5 g / L or more, or 10 g / L or more and may be 100 g / L or less, 50 g / L or less, 30 g / L or less, or 20 g / L or less. The amount of coating of the brazing filler metal at the second brazing fastening region is not particularly limited, but may be 1 g / L or more, 2 g / L or more, 5 g / L or more, or 10 g / L or more and may be 100 g / L or less, 50 g / L or less, 30 g / L or less, or 20 g / L or less.

[0040] FIG. 2 is a schematic view of a cross-section showing one aspect of the honeycomb carrier of the present invention, but the invention is not limited to this case.

[0041] The honeycomb body shown in FIG. 2 has a gas inflow side end part 110a and a gas outflow side end part 110b. Similarly, the honeycomb carrier has a gas inflow side end part 10a and gas outflow side end part 10b. The corrugated sheet and flat sheet forming the honeycomb body 110 are fastened together by brazing at the first brazing fastening region 111 of the gas outflow side end part 110b of the honeycomb body. Further, the honeycomb body 110 and jacket 120 are fastened together by brazing at the second brazing fastening region 121 of the gas outflow side end part 10b of the honeycomb carrier. The second brazing fastening region 121 is arranged at the gas outflow side end part 10b of the honeycomb carrier, so the brazing filler metal fastening the honeycomb body and jacket at the second brazing fastening region 121 can be kept from cracking due to the heat load etc. and thereby the honeycomb body 110 and jacket 120 can be kept from separating.

[0042] <Axial Direction Length of First Brazing Fastening Region and Second Brazing Fastening Region> In the honeycomb carrier of the present invention, the axial direction length of the first brazing fastening region is 1.2 times or less of the axial direction length of the second brazing fastening region.

[0043] The axial direction length of first brazing fastening region may be 0.8 time or more and 1.2 times or less of the axial direction length of the second brazing fastening region. The axial direction length of the first brazing fastening region may also be 0.2 time or more, 0.4 time or more, 0.6 time or more, 0.8 time or more, or 0.9 time or more of the axial direction length of second brazing fastening region and may be 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less.

[0044] For example, in the above-mentioned FIG. 2, the axial direction length 111a of the first brazing fastening region is the length from the gas outflow side end part 110b to the axial direction end part of the first brazing fastening region 111. Further, the axial direction length 121a of the second brazing fastening region is the length from the gas outflow side end part 10b to the axial direction end part of the second brazing fastening region 121. The axial direction length 111a of first brazing fastening region is smaller than the axial direction length 121a of the second brazing fastening region and 1.2 times or less of the axial direction length of second brazing fastening region. The first brazing fastening region 111 fastening the corrugated sheet and flat sheet of the honeycomb body 110 is positioned inside of the second brazing fastening region 121 fastening the honeycomb body 110 and jacket 120, so the honeycomb body and jacket can be strongly fastened at the second brazing fastening region 121. Due to this, the honeycomb body 110 and jacket 120 can be kept from separating. Note that, the axial direction length 111a of the first brazing fastening region is preferably 30% or more of that axial direction length of the honeycomb carrier, that is, the length from the gas inflow side end part 10a to the gas outflow side end part 10b.

[0045] <Third Brazing Fastening Region> In the honeycomb carrier of the present invention, the corrugated sheet and the flat sheet may be fastened together by brazing at a third brazing fastening region of the gas inflow side end part of the honeycomb body.

[0046] When brazing at the third brazing fastening region, the outer circumference part of the honeycomb carrier, that is, the outer circumference part of the honeycomb body, and the space between the honeycomb body and the jacket are masked by fixtures etc., then dipped in a slurry containing brazing filler metal powder to braze and fasten them. By doing this, fastening by brazing at the third brazing fastening region can be performed without brazing the outer circumference part of the honeycomb body and the space between the honeycomb body and the jacket.

[0047] The amount of coating of the brazing filler metal of the third brazing fastening region is not particularly limited, but from the viewpoint of improving the strength of the honeycomb body, an amount of coating of 10 g / L or more is preferable. The amount of coating of the brazing filler metal of the third brazing fastening region is not particularly limited, but may be 1 g / L or more, 2 g / L or more, 5 g / L or more, or 10 g / L or more and may be 100 g / L or less, 50 g / L or less, 30 g / L or less, or 20 g / L or less.

[0048] FIG. 3 is a schematic view of a cross-section showing one aspect of the honeycomb carrier of the present invention where the third brazing fastening region is provided, but the invention is not limited to this case.

[0049] In the honeycomb carrier shown in FIG. 3, the corrugated sheet and flat sheet forming the honeycomb body 110 are fastened together by brazing at the first brazing fastening region 111 of the gas outflow side end part 110b of the honeycomb body. Further, the honeycomb body 110 and jacket 120 are fastened together by brazing at the second brazing fastening region 121 of the gas outflow side end part 10b of the honeycomb carrier. Furthermore, the corrugated sheet and flat sheet forming the honeycomb body 110 are fastened together by brazing at the third brazing fastening region 112 of the gas inflow side end part 110a of honeycomb body. A honeycomb body is high in temperature at the gas inflow side and is directly contacted by the gas, so easily breaks due to the heat load and vibration. By the honeycomb body being brazed by the third brazing fastening region 112, the strength of the honeycomb body can be improved.

[0050] <Arrangement of Third Brazing Fastening Region> In the honeycomb carrier of the present invention, the honeycomb body may have a diametrical direction inside circumference region and diametrical direction outside circumference region, and the third brazing fastening region may be arranged only at the diametrical direction inside circumference region among the diametrical direction inside circumference region and the diametrical direction outside circumference region.

[0051] The third brazing fastening region is not particularly limited, but from the viewpoint of securing the strength of the honeycomb body and easing the stress due to the thermal expansion of the honeycomb body, is preferably arranged at the diametrical direction inside circumference region inside by one to three layers from the outermost circumference of the honeycomb body.

[0052] The diametrical direction outside circumference region may be the outermost circumference one layer or more, three layers or more, or five layers or more of the honeycomb body and may be 10 layers or less, 8 layers or less, 5 layers or less, or 3 layers or less.

[0053] FIG. 4A is a schematic view seen from the gas inflow side of the honeycomb carrier of the present invention where no third brazing fastening region is provided, but the invention is not limited to this case. Further, FIG. 4B is a schematic view seen from the gas inflow side of the honeycomb carrier of the present invention where a third brazing fastening region is provided, but the invention is not limited to this case.

[0054] Using FIG. 4A, the diametrical direction inside circumference region and diametrical direction outside circumference region of the honeycomb body will be explained. The honeycomb body 110 housed in the jacket 120 has a diametrical direction inside circumference region 110c and a diametrical direction outside circumference region 110d at the inside of the broken line shown in the honeycomb body 110. The honeycomb carrier shown in FIG. 4B has a third brazing fastening region 112. The third brazing fastening region 112 is arranged at only the diametrical direction inside circumference region 110c of the honeycomb body 110. Since the third brazing fastening region is arranged at only the diametrical direction inside circumference region of the honeycomb body, it is possible to improve the strength of the honeycomb body and possible to keep the honeycomb body and jacket from being fastened at the gas inflow side end part due to the outflow of the brazing filler metal.

[0055] <Axial Direction Length of Aperture-Free Region and Axial Direction Length of Third Brazing Fastening Region> In the honeycomb carrier of the present invention, at least one of the corrugated sheet and the flat sheet may have an aperture region at a center in the axial direction of the honeycomb body and an aperture-free region at an upstream side end in the axial direction of the honeycomb body, and the axial direction length of the aperture-free region at the upstream side end may be longer than the axial direction length of the third brazing fastening region.

[0056] FIGS. 5A and 5B are schematic views showing one aspect of the corrugated sheet and flat sheet included in the honeycomb body of the honeycomb carrier of the present invention, but the invention is not limited to this case.

[0057] FIG. 5A is a schematic view showing a corrugated sheet having apertures stretched out flat. The corrugated sheet 510 has an upstream side end 510c and downstream side end 510d in the axial direction of the honeycomb body and is provided with a plurality of apertures 511. This corrugated sheet 510 has an aperture-free region 510a where no apertures are present and an aperture region 510b were apertures are present at the upstream side end 510c in the axial direction of the honeycomb body. FIG. 5B is a schematic view showing a flat sheet. The flat sheet 520, in the same way as the corrugated sheet 510, has an upstream side end 520c and downstream side end 520d in the axial direction of the honeycomb body and is provided with a plurality of apertures 521. This flat sheet 520 has an aperture-free region 520a where no apertures are present and an aperture region 520b were apertures are present at the upstream side end 520c in the axial direction of the honeycomb body. The honeycomb body may be comprised of a corrugated sheet and flat sheet not having apertures or may be comprised of a corrugated sheet and flat sheet having apertures. At least one of the corrugated sheet and flat sheet having apertures may have an aperture region and an aperture-free region. Further, while not shown, an aperture-free region parallel to the upstream side end 510c and not having apertures may also be provided at a center zone of the corrugated sheet. In the same way, an aperture-free region parallel to the upstream side end 520c and not having apertures may also be provided at a center zone of the flat sheet.

[0058] The axial direction length of the aperture-free region at the upstream side end may be 1.0 time or more the axial direction length of third brazing fastening region, 1.1 times or more, 1.2 times or more, 1.3 times or more, or 1.5 times or more and 3.0 times or less, 2.5 times or less, 2.0 times or less, or 1.5 times or less.

[0059] FIG. 6 is a schematic view showing one aspect of the honeycomb carrier of the present invention, but the invention is not limited to this case.

[0060] The honeycomb body 110 of the honeycomb carrier 10 shown in FIG. 6 is comprised of a corrugated sheet and flat sheet having apertures such as shown in, for example, FIGS. 5A and 5B wound superposed. The axial direction length 510e of the aperture-free region of the corrugated sheet is the length from the gas inflow side end part 110a of the honeycomb body to the apertures 511 of the corrugated sheet close to the gas inflow side end part 110a. Further, the axial direction length 520e of the aperture-free region of the flat sheet is the length from the gas inflow side end part 110a of the honeycomb body to the apertures 521 of the flat sheet close to the gas inflow side end part 110a. Further, the axial direction length 112a of the third brazing fastening region is the length from the gas inflow side end part 110a to the axial direction end part of the third brazing fastening region 112. In FIG. 6, the axial direction length 510e of the aperture-free region of the corrugated sheet and the axial direction length 520e of the aperture-free region of the flat sheet are both longer than the axial direction length 112a of the third brazing fastening region. At least one of the axial direction length of the aperture-free region of the corrugated sheet and the axial direction length of the aperture-free region of the flat sheet is longer than the axial direction length of the third brazing fastening region, so at the brazing fastening, even when the brazing filler metal is heated and is rendered a liquid, the brazing filler metal can be prevented from flowing from honeycomb body and contacting the jacket. At least one of the axial direction length of the aperture-free region of the corrugated sheet and the axial direction length of the aperture-free region of the flat sheet may be longer than the axial direction length of the third brazing fastening region.

[0061] <Position of Axial Direction End Part of Third Brazing Fastening Region> In the honeycomb carrier of the present invention, at least one of the corrugated sheet and flat sheet may has apertures, and an axial direction end part of the third brazing fastening region may be superposed over the apertures of only one of the corrugated sheet or the flat sheet or need not be superposed over the apertures of any of the corrugated sheet or the flat sheet.

[0062] If the axial direction end part of the third brazing fastening region is superposed over the apertures, at the superposed part, the strength is expected to fall. Therefore, the axial direction end part of the third brazing fastening region is not particularly limited, but from the viewpoint of securing the strength of the honeycomb body, preferably it is superposed over the apertures of only one of the corrugated sheet or flat sheet or preferably it is not superposed over the apertures of any of the corrugated sheet or flat sheet.

[0063] FIGS. 7A and 7B are schematic views showing one aspect of the honeycomb carrier of the present invention in which a honeycomb body comprised of a corrugated sheet and flat sheet having apertures is provided, but the invention is not limited to this.

[0064] In the above-mentioned FIG. 6, the axial direction end part of the third brazing fastening region 112b is not superposed over the apertures 511 of the corrugated sheet or apertures 521 of the flat sheet. In the honeycomb carrier of FIG. 7A, the axial direction end part of the third brazing fastening region 112b is superposed over the apertures 511 of the corrugated sheet and not superposed over the apertures 521 of the flat sheet. Further, in the honeycomb carrier of FIG. 7B, the axial direction end part of the third brazing fastening region 112b is not superposed over the apertures 511 of the corrugated sheet and is superposed over the apertures 521 of the flat sheet 521. In the honeycomb bodies of FIG. 6, FIG. 7A, and FIG. 7B, the axial direction end part of the third brazing fastening region is superposed over the apertures of only one of the corrugated sheet or flat sheet or is not superposed over the apertures of any of the corrugated sheet or flat sheet, so it is possible to secure the strength of the honeycomb body.

[0065] <<Exhaust Gas Purification Method>> The exhaust gas purification method of the present invention comprises making exhaust gas circulate through the honeycomb carrier of the present invention so as to purify the exhaust gas.

[0066] The honeycomb carrier of the present invention may have a catalyst layer at the metallic corrugated sheet and / or flat sheet. As the catalyst layer, it is possible to adopt a configuration known in the field as a catalyst layer having an exhaust gas purification ability. For example, the catalyst layer can have a metal oxide carrier provided on the surface of the metallic corrugated sheet and / or flat sheet and a precious metal carried on the carrier.

[0067] As the metal oxide carrier, for example, ceria, alumina, rare earth oxides, etc. and composite oxides comprised of several of these can be mentioned.

[0068] As examples of precious metals, for example, platinum, palladium, rhodium, etc. can be mentioned. These precious metal can, for example, be carried at the metal oxide carrier as particles of particle sizes of 1 nm or more and 100 nm or less.

[0069] The step of forming a layer of a metal oxide carrier on a metallic corrugated sheet and / or flat sheet can, for example, include preparation of a solution or slurry containing one or more types of material selected from metal oxides and / or their precursors, coating the metallic corrugated sheet and / or flat sheet by that solution or slurry, and optionally firing the same.

[0070] The exhaust gas purification method is not particularly limited, but, for example, the method may be employed of making exhaust gas from the internal combustion engine circulate through the honeycomb carrier to make it contact the same and thereby purify the exhaust gas. The internal combustion engine is not particularly limited, but a known internal combustion engine can be suitably used. For example, an engine of a gasoline vehicle or motorcycle, a diesel engine, a lean burn type engine with a low fuel consumption rate, etc. may be mentioned.

[0071] 10 honeycomb carrier 10a gas inflow side end part of honeycomb carrier 10b gas outflow side end part of honeycomb carrier 110 honeycomb body 110a gas inflow side end part of honeycomb body 110b gas outflow side end part of honeycomb body 110c diametrical direction inside region 110d diametrical direction outside region 111 first brazing fastening region 111a axial direction length of first brazing fastening region 112 third brazing fastening region 112a axial direction length of third brazing fastening region 112b axial direction end part of third brazing fastening region 120 jacket 121 second brazing fastening region 121a axial direction length of second brazing fastening region 510 corrugated sheet 510a aperture-free region of corrugated sheet 510b aperture region of corrugated sheet 510c upstream side end of corrugated sheet 510d downstream side end of corrugated sheet 510e axial direction length of aperture-free region of corrugated sheet 511 aperture of corrugated sheet 520 flat sheet 520a aperture-free region of flat sheet 520b aperture region of flat sheet 520c upstream side end of flat sheet 520d downstream side end of flat sheet 520e axial direction length of aperture-free region of flat sheet 521 aperture of flat sheet

Claims

1. A honeycomb carrier, wherein the honeycomb carrier has a honeycomb body comprised of a metallic corrugated sheet and a metallic flat sheet wound superposed and a jacket housing that honeycomb body, the corrugated sheet and the flat sheet are fastened with each other by brazing at a first brazing fastening region of a gas outflow side end part of the honeycomb body, the honeycomb body and the jacket are fastened with each other by brazing at a second brazing fastening region of the gas outflow side end part of the honeycomb body, and an axial direction length of the first brazing fastening region is 1.2 times or less an axial direction length of the second brazing fastening region.

2. The honeycomb carrier according to claim 1, wherein the axial direction length of the first brazing fastening region is 0.8 time or more and 1.2 times or less of the axial direction length of the second brazing fastening region.

3. The honeycomb carrier according to claim 1, wherein the corrugated sheet and the flat sheet are fastened together by brazing at a third brazing fastening region of a gas inflow side end part of the honeycomb body.

4. The honeycomb carrier according to claim 1, wherein the honeycomb body has a diametrical direction inside circumference region and diametrical direction outside circumference region, and the third brazing fastening region is arranged only at the diametrical direction inside circumference region among the diametrical direction inside circumference region and the diametrical direction outside circumference region.

5. The honeycomb carrier according to claim 1, wherein at least one of the corrugated sheet and the flat sheet has an aperture region at a center in the axial direction of the honeycomb body and an aperture-free region at an upstream side end in the axial direction of the honeycomb body, and an axial direction length of the aperture-free region at the upstream side end is longer than the axial direction length of the third brazing fastening region.

6. The honeycomb carrier according to claim 1, wherein at least one of the corrugated sheet and flat sheet has apertures, and an axial direction end part of the third brazing fastening region is superposed over the apertures of only one of the corrugated sheet or the flat sheet or is not superposed over the apertures of any of the corrugated sheet or the flat sheet.

7. An exhaust gas purification method, comprising making exhaust gas following through a honeycomb carrier according to any one of claims 1 to 6 so as to purify the exhaust gas.

Images