Apparatus and methods for manufacturing honeycomb filters

Abstract

A honeycomb filter includes a body including an inlet end, an outlet end, a body axis extending between the inlet end and the outlet end, and a plurality of intersecting porous walls extending along the body axis. The honeycomb filter includes a plurality of inlet channels extending along the body axis and inlet openings at the inlet end. The plurality of inlet channels include inlet corners including an inlet corner radius. A plurality of outlet channels extend along the body axis between the inlet end and the outlet end and include outlet openings at the outlet end. The plurality of outlet channels include outlet corners including an outlet corner radius. A ratio of the inlet corner radius to the outlet corner radius is less than about 1. Methods of manufacturing a honeycomb filter are provided.

Description

APPARATUS AND METHODS FOR MANUFACTURING HONEYCOMB FILTERSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application No. 63 / 756,320 filed February 10, 2025, the content of which is incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates generally to honeycomb filters and, more particularly, to honeycomb filters comprising outlet channels with rounded comers.BACKGROUND

[0003] It is known to manufacture honeycomb filters for use in exhaust after-treatment systems. However, balancing a mass of the honeycomb filter with a pressure drop through the honeycomb filter can be difficult. Further, honeycomb filters are subject to wear due to elevated temperatures to which the honeycomb filters are exposed.SUMMARY

[0004] The following presents a simplified summary of the disclosure to provide a basic understanding of some aspects described in the detailed description.

[0005] In aspects, a honeycomb filter comprises a body comprising an inlet end, an outlet end, a body axis extending between the inlet end and the outlet end, and a plurality of intersecting porous walls extending along the body axis. The honeycomb filter comprises a plurality of inlet channels formed by the plurality of intersecting porous walls, the plurality of inlet channels extending along the body axis between the inlet end and the outlet end and comprising inlet openings at the inlet end. The plurality of inlet channels comprise inlet comers comprising an inlet corner radius. The honeycomb filter comprises a plurality of outlet channels formed by the plurality of intersecting porous walls. The plurality of outlet channels extend along the body axis between the inlet end and the outlet end and comprise outlet openings at the outlet end. The plurality of outlet channels comprise outlet comers comprising an outlet comer radius, wherein a ratio of the inlet comer radius to the outlet corner radius is less than about 1, for example less than about 1.0.

[0006] In aspects, a separating distance between an inlet channel of the plurality of inlet channels and an adjacent outlet channel of the plurality of outlet channels is within a range from about 0.2 millimeters to about 0.5 millimeters. The separating distance is a wall thickness of one of the plurality of intersecting porous walls between the inlet channel and the adjacent outlet channel.

[0007] In aspects, a channel density of the honeycomb filter is within a range from about 250 cells per square inch to about 350 cells per square inch. The cells are two-dimensional cross-sectional shapes of the plurality of inlet channels and the plurality of outlet channels along a plane perpendicular to the body axis.

[0008] In aspects, an outlet length of an outlet channel is defined between opposing parallel outlet walls of the plurality of intersecting porous walls forming the outlet channel, and a ratio of the outlet comer radius to the outlet length is within a range from about 0.2 to about 0.4.

[0009] In aspects, the ratio of the outlet comer radius to the outlet length is within a range from about 0.2 to about 0.3.

[0010] In aspects, an inlet length of an inlet channel is defined between opposing parallel inlet walls of the plurality of intersecting porous walls forming the inlet channel, and a ratio of the inlet comer radius to the inlet length is less than about 0.1.

[0011] In aspects, the ratio of the inlet corner radius to the inlet length is less than about 0.05.

[0012] In aspects, a honeycomb filter comprises a body comprising an inlet end, an outlet end, a body axis extending between the inlet end and the outlet end, and a plurality of intersecting porous walls extending along the body axis. The honeycomb filter comprises a plurality of inlet channels formed by the plurality of intersecting porous walls. The plurality of inlet channels extend along the body axis between the inlet end and the outlet end and comprise inlet openings at the inlet end. The plurality of inlet channels comprise inlet comers comprising an inlet comer radius and an inlet length between opposing parallel inlet walls of the plurality of intersecting porous walls. A ratio of the inlet comer radius to the inlet length is less than about 0.05. The honeycomb filter comprises a plurality of outlet channels surrounded by the plurality of intersecting porous walls. The plurality of outlet channels extend along the body axis between the inlet end and the outlet end and comprise outlet openings at the outlet end. The plurality of outlet channels comprise outlet comers comprising an outlet comer radius and an outlet length between opposing parallel outlet walls of the plurality ofintersecting porous walls. A ratio of the outlet corner radius to the outlet length is within a range from about 0.2 to about 0.4.

[0013] In aspects, a separating distance between an inlet channel of the plurality of inlet channels and an adjacent outlet channel of the plurality of outlet channels is within a range from about 0.2 millimeters to about 0.5 millimeters. The separating distance is a wall thickness of one of the plurality of intersecting porous walls between the inlet channel and the adjacent outlet channel.

[0014] In aspects, a channel density is within a range from about 250 cells per square inch to about 350 cells per square inch. The cells are two-dimensional cross-sectional shapes of the plurality of inlet channels and the plurality of outlet channels along a plane perpendicular to the body axis.

[0015] In aspects, the ratio of the outlet comer radius to the outlet length is within a range from about 0.2 to about 0.3.

[0016] In aspects, methods of manufacturing a honeycomb filter comprise forming a body extending along a body axis between an inlet end and an outlet end. The body comprises a plurality of intersecting porous walls extending along the body axis. The body comprises a plurality of inlet channels extending along the body axis between the inlet end and the outlet end. The plurality of inlet channels comprise inlet openings at the inlet end and inlet corners comprising an inlet comer radius. The body comprises a plurality of outlet channels comprising outlet comers comprising an outlet comer radius. A ratio of the inlet comer radius to the outlet corner radius is less than about 1, for example less than about 1.0.

[0017] In aspects, methods comprise selecting the outlet comer radius to increase a total mass of the honeycomb filter without increasing a pressure drop through the honeycomb filter.

[0018] In aspects, methods comprise separating an inlet channel of the plurality of inlet channels from an adjacent outlet channel of the plurality of outlet channels such that a separating distance between the inlet channel and the adjacent outlet channel is within a range from about 0.2 millimeters to about 0.5 millimeters. The separating distance is a wall thickness of one of the plurality of intersecting porous walls between the inlet channel and the adjacent outlet channel.

[0019] In aspects, the plurality of inlet channels and the plurality of outlet channels are formed such that a channel density of the honeycomb filter is within a range from about 250 cells per square inch to about 350 cells per square inch. The cells are two-dimensional cross-sectional shapes of the plurality of inlet channels and the plurality of outlet channels along a plane perpendicular to the body axis.

[0020] In aspects, the plurality of inlet channels comprise an inlet length of an inlet wall of the plurality of intersecting porous walls forming one of the plurality of inlet channels, and a ratio of the inlet comer radius to the inlet length is less than 0.05.

[0021] In aspects, the plurality of outlet channels comprise an outlet length of an outlet wall of the plurality of intersecting porous walls forming one of the plurality of outlet channels, and a ratio of the outlet corner radius to the outlet length is within a range from about 0.2 to about 0.4.

[0022] Additional features and advantages of the aspects disclosed herein will be set forth in the detailed description that follows, and in part will be clear to those skilled in the art from that description or recognized by practicing the aspects described herein, including the detailed description which follows, the claims, as well as the appended drawings. It is to be understood that both the foregoing general description and the following detailed description present aspects intended to provide an overview or framework for understanding the nature and character of the aspects disclosed herein. The accompanying drawings are included to provide further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various aspects of the disclosure, and together with the description explain the principles and operations thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] These and other features, aspects and advantages are better understood when the following detailed description is read with reference to the accompanying drawings, in which:

[0024] FIG. 1 is a perspective illustration of a honeycomb filter in accordance with aspects of the disclosure;

[0025] FIG. 2 illustrates an inlet end of the honeycomb filter in accordance with aspects of the disclosure;

[0026] FIG. 3 illustrates an outlet end of the honeycomb filter in accordance with aspects of the disclosure;

[0027] FIG. 4 illustrates inlet channels and outlet channels of the honeycomb filter in accordance with aspects of the disclosure;

[0028] FIG. 5 illustrates a plot of a mass increase percentage, a hydraulic diameter increase percentage, and a surface area reduction percentage in accordance with aspects of the disclosure;

[0029] FIG. 6 illustrates a bar graph comparing various dimensional changes of the honeycomb filter in accordance with aspects of the disclosure;

[0030] FIG. 7 illustrates a bar graph comparing various dimensional changes of the honeycomb filter in accordance with aspects of the disclosure;

[0031] FIG. 8 illustrates a bar graph comparing various dimensional changes of the honeycomb filter in accordance with aspects of the disclosure; and

[0032] FIG. 9 illustrates a bar graph comparing various dimensional changes of the honeycomb filter in accordance with aspects of the disclosure.DETAILED DESCRIPTION

[0033] Aspects will now be described more fully hereinafter with reference to the accompanying drawings in which example aspects are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the aspects set forth herein.

[0034] As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not, and need not be, exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art.

[0035] Ranges can be expressed herein as from “about” one value, and / or to “about” another value. When such a range is expressed, aspects include from the one value to the other value. Similarly, when values are expressed as approximations by use of the antecedent “about,” it will be understood that the value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0036] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom, upper, lower, etc. - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0037] Unless otherwise expressly stated, it is in no way intended that any methods set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus, specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred in any respect. This holds for any possible non-express basis for interpretation, including matters of logic relative to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of aspects described in the specification.

[0038] As used herein, the singular forms "a," "an" and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0039] The word “exemplary,” “example,” or various forms thereof are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” or as an “example” should not be construed as preferred or advantageous over other aspects or designs. Furthermore, examples are provided solely for purposes of clarity and understanding and are not meant to limit or restrict the disclosed subject matter or relevant portions of this disclosure in any manner. It can be appreciated that a myriad of additional or alternate examples of varying scope could have been presented but have been omitted for purposes of brevity.

[0040] As used herein, the terms “comprising” and “including”, and variations thereof, shall be construed as synonymous and open-ended, unless otherwise indicated. A list of elements following the transitional phrases comprising or including is a non-exclusive list, such that elements in addition to those specifically recited in the list may also be present.

[0041] The terms “substantial,” “substantially,” and variations thereof as used herein are intended to represent that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, “substantially” is intended to denote that two values are equal or approximately equal. The term “substantially” may denote values withinabout 10% of each other, for example, within about 5% of each other, within about 2%, within about 1%, or within about 0.5% of each other.

[0042] Modifications may be made to the instant disclosure without departing from the scope or spirit of the claimed subject matter. Unless specified otherwise, “first,” “second,” or the like are not intended to imply a temporal aspect, a spatial aspect, an ordering, etc. Rather, such terms are merely used as identifiers, names, etc. for features, elements, items, etc. For example, a first end and a second end generally correspond to end A and end B or two different ends.

[0043] FIG. 1 is a perspective illustration of a honeycomb filter 100. The honeycomb filter 100 comprises a body 101 extending between an inlet end 103 and an outlet end 105, with a body axis 107 extending between the inlet end 103 and the outlet end 105. While the body 101 comprises a substantially cylindrical cross-sectional shape in FIG. 1, other possible cross-sectional shapes (e.g., oval cross-sectional shape, quadrilateral cross-sectional shape, etc.) are possible. The body 101 comprises a length 109 extending between the inlet end 103 and the outlet end 105 along the body axis 107. The honeycomb filter 100 can receive gas (e.g., exhaust gas, such as from a gasoline or diesel engine ) along an inlet direction 111 through the inlet end 103. The exhaust gas is filtered by the honeycomb filter 100 (e.g., by porous walls of the honeycomb filter 100) before exiting the outlet end 105 in an outlet direction 113. In aspects, an outer peripheral skin 117 can extend along the length 109 and may be applied to an outer circumferential periphery of the body 101 as an after-applied skin or may be extruded concurrently with the body 101.

[0044] The body 101 can comprise a plurality of intersecting porous walls 121 that extend along the body axis 107 between the inlet end 103 and the outlet end 105. The plurality of intersecting porous walls 121 can intersect one another in a radial direction perpendicular to the body axis 107 to form a plurality of channels 125. The plurality of channels 125 are a series of hollow, elongated passageways that are defined or formed by the plurality of intersecting porous walls 121. In aspects, a first group 123 (e.g., illustrated in FIG. 2) of the plurality of intersecting porous walls 121 can extend along an x-axis that is perpendicular to the body axis 107, while a second group 124 (e.g., illustrated in FIG.2) of the plurality of intersecting porous walls 121 can extend along a y-axis that is perpendicular to the body axis 107, with the x-axis perpendicular to the y-axis. In this way, the plurality of intersecting porous walls 121 can intersect one another to form a honeycomb structure within the body 101.

[0045] The plurality of channels 125 can comprise a plurality of inlet channels 127 and a plurality of outlet channels 129 that extend along the body axis 107 between the inlet end 103 and the outlet end 105. The plurality of intersecting porous walls 121 can form the plurality of inlet channels 127 and the plurality of outlet channels 129 while the plurality of intersecting porous walls 121 extend longitudinally along the body axis 107. The plurality of inlet channels 127 can comprise the same shape and / or cross-sectional area as the plurality of outlet channels 129, or, alternatively, the plurality of inlet channels 127 can comprise a different and / or larger cross-sectional area than the plurality of outlet channels 129. The plurality of inlet channels 127 can comprise inlet openings 131 at the inlet end 103, while the plurality of outlet channels 129 may be plugged proximate the inlet end 103. The plurality of outlet channels 129 are illustrated as being plugged at the inlet end 103 by shaded portions in FIG. 1. In aspects, the plurality of channels 125 may be arranged in a checkerboard pattern with the plurality of inlet channels 127 alternating with the plurality of outlet channels 129 along the x-axis and the y-axis. In aspects, zero or more channels of the plurality of channels 125 may be pass-through channels that are unplugged and extend uninterrupted through the body 101 between the inlet end 103 and the outlet end 105. In aspects, the number of inlet channels 127 may be equal to the number of outlet channels 129, though, in other aspects, there may be more inlet channels 127 than outlet channels 129.

[0046] The honeycomb filter 100 described herein can be used as part of an after-treatment process for exhaust gas from internal combustion engines. The honeycomb filter 100 can comprise one or more of the following characteristics, such as being thermal shock resistant, refractory, and non-reactive with a catalyst system (e.g., wherein the ceramic used to form the honeycomb filter 100 does not react with a catalyst that is supported by the body 101) while providing low resistance to exhaust gas flow. In aspects, the honeycomb filter 100 can be formed by an extrusion process wherein a ceramic batch mixture is extruded from an extrusion die and then dried and fired to form the final ceramic honeycomb body. The ceramic used to form the honeycomb filter 100 can comprise cordierite, aluminum titanate, silicon carbide, silicon nitride, alumina, mullite, combinations thereof, or other suitable materials.

[0047] FIG.2 illustrates a close-up view at focus circle 2 of FIG. 1 of the inlet end 103 of the body 101. As illustrated, the plurality of outlet channels 129 can be plugged to limit the exhaust gas from entering the inlet end 103 through the plurality of outlet channels 129. Rather, the plurality of inlet channels 127 can comprise the inlet openings 131 through which the exhaust gas can flow through and enter the inlet end 103 of the body 101. As described herein,the plurality of outlet channels 129 can comprise a quadrilateral (e.g., rectangular, square, etc.) cross-sectional shape with rounded comers. The plurality of inlet channels 127 can comprise a quadrilateral (e.g., rectangular, square, etc.) cross-sectional shape with non-rounded comers, or with corners that are rounded but with a reduced radius of curvature as compared to the rounded corners of the plurality of outlet channels 129. As used herein, a rounded comer of the channels 127, 129 can also be referred to as a fillet, which comprises an arcuate shape with a radius and is located at an interior corner of two intersecting walls.

[0048] FIG. 3 illustrates a close-up view of the outlet end 105 of the body 101. As illustrated, the plurality of inlet channels 127 can be plugged at the outlet end 105 to limit or prevent the exhaust gas from exiting the outlet end 105 through the plurality of inlet channels 127. Rather, the plurality of outlet channels 129 can comprise outlet openings 301 at the outlet end 105. Exhaust gas entering an inlet channel is blocked from exiting the inlet channel at the outlet end and is forced through the porous walls of the inlet channel into an adjacent outlet channel, through which the exhaust gas can flow and exit the outlet channel 129 at the outlet end 105 of the body 101. By plugging the inlet channels 127 at the outlet end 105 and the outlet channels 129 at the inlet end 103, the exhaust gas can be filtered by passing through the porous walls of the honeycomb filter 100. That is, the exhaust gas can travel from the inlet channels 127, through the porous walls 121, and into the outlet channels 129 prior to exiting the honeycomb filter 100. In this way, the porous walls 121 can function to filter components or particulates (e.g., soot) from the exhaust gas within the honeycomb filter 100. In addition, in aspects, some or all of the porous walls 121 can comprise an on-wall or in-wall catalyst to catalyze components (e.g., NOX, SOX, CO, etc.) in the exhaust gas. After soot and / or other particulates have accumulated on or in the porous walls 121, a regeneration event can occur in which the temperature of the honeycomb filter 100 can be increased to a level that causes removal or burning of the soot and / or other particulates.

[0049] FIG. 4 illustrates an enlarged view of four channels of the plurality of channels 125 at the inlet end 103, wherein the four channels comprise two adjacent inlet channels (e.g., a first inlet channel 401 and a second inlet channel 403) and two adjacent outlet channels (e.g., a first outlet channel 405 and a second outlet channel 407). For the purposes of illustration, FIG. 4 illustrates the four channels 401, 403, 405, 407, but the other channels of the plurality of channels 125 may be substantially similar or identical to the channels 401, 403, 405, 407 of FIG. 4. Further, for the purposes of illustration, the shading denoting plugs in the outlet channels 129 (e.g., illustrated in FIGS. 1-2) and the shading denoting plugs in the inlet channels127 (e.g., illustrated in FIG. 3) is not illustrated in FIG. 4, but would otherwise be present at the locations illustrated in FIGS. 1-3.

[0050] The first inlet channel 401 may be substantially identical to the second inlet channel 403. For example, the first inlet channel 401 can comprise a substantially square cross-sectional shape surrounded by a first pair of inlet walls 409 and a second pair of inlet walls 411. The first pair of inlet walls 409 are spaced apart from, and parallel to, one another. The second pair of inlet walls 411 are spaced apart from, and parallel to, one another while extending substantially perpendicular to the first pair of inlet walls 409. In aspects, the first inlet channel 401 can comprise a first inlet dimension, such as, for example, an inlet length 413 defined between the first pair of inlet walls 409 along the y-axis, and a second inlet dimension, such as, for example, an inlet width 415 defined between the second pair of inlet walls 411 along the x-axis. As illustrated in FIG. 4, the inlet length 413 may be substantially equal to the inlet width 415 such that the first inlet channel 401 comprises the square shape, though, in aspects, the inlet length 413 can be different than the inlet width 415, such that the first inlet channel 401 can comprise a rectangular shape or other elongated shape. In aspects, if the first inlet channel 401 (e.g., or any other inlet or outlet channels) comprises a cross-sectional shape with more than four sides (e.g., a five-sided pentagon shape, for example), the inlet length 413 can comprise a length of one of the walls, for example, the distance that the wall extends between opposing walls to which the wall is connected. For example, when the first inlet channel 401 comprises a five-sided shape, the inlet length 413 can comprise the length of the inlet wall 411 between opposing walls (e.g., 409) to which the inlet wall 411 is connected. Likewise, when the first outlet channel 405 comprises a five-sided shape, the outlet length 433 can comprise the length of the outlet wall 431 between opposing walls (e.g., 429) to which the outlet wall 431 is connected.

[0051] In aspects, the inlet length 413 is measured between parallel segments of the first pair of inlet walls 409. For example, the inlet length 413 can be measured at a midpoint of the first pair of inlet walls 409 halfway between second pair of inlet walls 411. In this way, in aspects, the inlet length 413 can comprise a maximum distance between the first pair of inlet walls 409 along the y-axis. The inlet width 415 can be measured between parallel segments of the second pair of inlet walls 411. For example, the inlet width 415 can be measured at a midpoint of the second pair of inlet walls 411 halfway between the first pair of inlet walls 409. In this way, in aspects, the inlet width 415 can comprise a maximum distance between the second pair of inlet walls 411 along the x-axis.

[0052] The first inlet channel 401, along with the remaining plurality of inlet channels 127, can comprise a plurality of inlet comers 417 at the intersection of the first pair of inlet walls 409 and the second pair of inlet walls 411. In aspects, the inlet corners 417 may comprise an inlet comer radius 419 that may be minimized. For example, a ratio of the inlet corner radius 419 to the inlet length 413 or the inlet width 415 may be less than about 0.1, or less than about 0.05, or less than about 0.03, or less than about 0.01.

[0053] The first outlet channel 405 may be substantially identical to the second outlet channel 407. For example, the first outlet channel 405 can comprise a substantially square cross-sectional shape surrounded by a first pair of outlet walls 429 and a second pair of outlet walls 431. The first pair of outlet walls 429 are spaced apart from, and parallel to, one another. The second pair of outlet walls 431 are spaced apart from, and parallel to, one another while being substantially perpendicular to the first pair of outlet walls 429. In aspects, the first outlet channel 405 can comprise a first outlet dimension, such as, for example, an outlet length 433 defined between the first pair of outlet walls 429 along the y-axis, and a second outlet dimension, such as, for example, an outlet length 433 defined between the second pair of outlet walls 431 along the x-axis. As illustrated in FIG. 4, the outlet length 433 may be substantially equal to the outlet width 435 such that the first outlet channel 405 comprises a square shape, though, in aspects, the outlet length 433 can be different than the outlet width 435, such that the first outlet channel 405 can comprise a rectangular shape (e.g., wherein a square shape is a rectangle with four equal sides). In aspects, the outlet length 433 is measured between parallel segments of the first pair of outlet walls 429.

[0054] In aspects, the outlet length 433 is measured between parallel segments of the first pair of outlet walls 429. For example, the outlet length 433 can be measured at a midpoint of the first pair of outlet walls 429 halfway between second pair of outlet walls 431. In this way, in aspects, the outlet length 433 can comprise a maximum distance between the first pair of outlet walls 429 along the y-axis. The outlet width 435 can be measured between parallel segments of the second pair of outlet walls 431. For example, the outlet width 435 can be measured at a midpoint of the second pair of outlet walls 431 halfway between the first pair of outlet walls 429. In this way, in aspects, the outlet width 435 can comprise a maximum distance between the second pair of outlet walls 431 along the x-axis.

[0055] The first outlet channel 405, along with the remaining plurality of outlet channels 129, can comprise a plurality of outlet comers 437 at the intersection of the first pair of outlet walls 429 and the second pair of outlet walls 431. In aspects, the outlet corners 437may comprise an outlet corner radius 439 that may be selected to increase a mass of the honeycomb filter 100 while maximizing a hydraulic diameter of the outlet channels 129 and limiting an increase in backpressure within the honeycomb filter 100. For example, a ratio of the outlet comer radius 439 to the outlet length 433 or the outlet width 435 may be within a range from about 0.1 to about 0.5, within a range from about 0.2 to about 0.4, in a range from about 0.1 to about 0.3, in a range from about 0.1 to about 0.2, in a range from about 0.2 to about 0.5, in a range from about 0.3 to about 0.5, in a range from about 0.4 to about 0.5, including all ranges and subranges therebetween. For example, the ratio of the outlet comer radius 439 to the outlet length 433 or the outlet width 435 may be within a range from about 0.15 to about 0.45, or within a range from about 0.25 to about 0.35. In aspects, the ratio of the outlet corner radius 439 to the outlet length 433 or the outlet width 435 may be within a range from about 0.2 to about 0.3, or about 0.35. In aspects, a ratio of the inlet corner radius 419 to the outlet corner radius 439 may be less than about 1, for example less than about 1.0. Accordingly, in aspects, the inlet corner radius 419 may be less than the outlet comer radius 439. In aspects, the ratio of the inlet comer radius 419 to the inlet length 413 may be less than 0.1, or less than 0.05. By reducing the inlet corner radius 419, a pressure drop, or back pressure, within the inlet channels may be reduced.

[0056] In aspects, adjacent inlet channels and outlet channels can be spaced a distance apart, for example, with one of the inlet walls 411 spaced a distance apart from an adjacent outlet wall 431 (e.g., parallel portions of inlet walls 411 spaced the distance apart from parallel portion of the outlet wall 431). In aspects, a separating distance 441 between the adjacent inlet wall 411 and outlet wall 431 (e.g., between an adjacent inlet channel and outlet channel) may be equivalent to a thickness of the porous wall 121, and may be in a range from about 2 mils (about 0.05 mm) to about 20 mils (about 0.5 mm), in a range from about 10 mils (about 0.25 mm) to about 20 mils (about 0.5 mm), in a range from about 2 mils (0.05 mm) to about 15 mils (about 0.38 mm), in a range from about 2 mils (0.05 mm) to about 13 mils (about 0.33 mm), from about 4 mils (about 0.1 mm) to about 10 mils (0.25 mm), from about 5 mils (about 0.13 mm) to about 10 mils (about 0.25 mm), or from about 7 mils (about 0.18 mm) to about 10 mils (0.25 mm), or from about 5 mils (about 0.15 mm) to about 8 mils (about 0.2 mm). In embodiments, a separating distance 441 between the adjacent inlet wall 411 and outlet wall 431 (e.g., between an adjacent inlet channel and outlet channel) may be less than about 8 mils (about 0.2 mm), or less than about 7 mils (0.18 mm). In embodiments, a separating distance 441 between the adjacent inlet wall 411 and outlet wall 431 may be in a range from about 0.05mm to about 0.5 mm, for example in a range from about 0.06 mm to about 0.5 mm, in a range from about 0.07 mm to about 0.5 mm, in a range from about 0.08 mm to about 0.5 mm, in a range from about 0.09 mm to about 0.5 mm, in a range from about 0.1 mm to about 0.5 mm, in a range from about 0.2 mm to about 0.5 mm, in a range from about 0.3 mm to about 0.5 mm, in a range from about 0.4 mm to about 0.5 mm, in a range from about 0.05 mm to about 0.4 mm, in a range from about 0.05 mm to about 0.3 mm, in a range from about 0.05 mm to about 0.2 mm, or in a range from about 0.05 mm to about 0.1 mm, including all ranges and subranges therebetween. In aspects, the honeycomb filter 100 can comprise a channel density (e.g., a number of channels 125 per square inch) in a range from about 250 cells, or channels, per square inch (“cpsi”) to about 450 cpsi, or within a range from about 250 cpsi to about 350 cpsi, or within a range from about 350 cpsi to about 450 cpsi. As used herein, a cell can represent the two-dimensional cross-sectional shape of the channel (e.g., inlet channels 127 or outlet channels 129) in cross-section along a plane perpendicular to the body axis 107, while the channel can represent the three-dimensional shape defined by the porous walls 121 that extend along the length 109 of the body 101. Further, as used herein, the separating distance 441 can comprise the wall thickness of one of the plurality of intersecting porous walls 121 between an inlet channel and an adjacent outlet channel, for example, between the first inlet channel 401 and the first outlet channel 405.

[0057] The perimeter of each of the outlet channels (e.g., the first outlet channel 405, the second outlet channel 407, etc.) can be defined by the equation: P = 4L — 2(4 — ?r)r, wherein P is the perimeter of the first outlet channel 405, L is the outlet length 433 between opposing parallel walls, and r is the outer comer radius 439. The open area of each of the outlet channels (e.g., the first outlet channel 405, the second outlet channel 407, etc.) in a plane orthogonal to the body axis 107 can be defined by the equation: A = L2— (4 — 7r)r2, wherein A is the open area of the first outlet channel 405. The hydraulic diameter of the outlet channels (e.g., the first outlet channel 405, the second outlet channel 407, etc.) can be defined by the equation: HD= 4- wherein HD is the hydraulic diameter of the first outlet channel 405. The solid area of the outlet channels (e.g., the first outlet channel 405, the second outlet channel407, etc.) can be defined by the equation: — A, wherein Asis the solid area ofthe first outlet channel 405, and cpsi is the number of cells (or channels) per square inch. The solid area of the channels is the surface area of the porous walls 121 that form one of the channels, such that the solid area of the channels can represent the area of the solid material(e.g., porous wall 121) that surrounds one of the channels. The channel hydraulic diameter increase percentage compared to no fillet (e.g., compared to a radius of zero for the corners) can be defined by the equation: AHD= ^ — 1, wherein AHDis the channel hydraulic diameter increase percentage. The channel solid area (e.g., mass) increase percentage compared to no fillet (e.g., compared to a radius of zero for the corners) can be defined by the equation: Ads= As—L2- - -2 - 1. The outlet length 433 between opposing parallel walls can be defined by the I \- / Tcpsi ~L21equation L = , —:— w, wherein w is a web thickness of wall thickness of one of the porous jcpsiwalls 121. Accordingly, these equations illustrate that increasing the outlet corner radius can increase the surface area of the porous walls 121 of the honeycomb filter 100, but will reduce the open area of each of the outlet channels. An increase in the surface area of the porous walls 121 produces an increase in mass of the honeycomb filter 100. Despite a possible reduction in open area of the outlet channels, the hydraulic diameter HD can be increased with a larger outlet comer radius.

[0058] In aspects, the body 101 of the honeycomb filter 100 can be formed by an extrusion process in which a ceramic batch mixture can be extruded from an extrusion die into a green form, dried, and fired to form the honeycomb body 101. The honeycomb extrusion die can be formed by a plunge electron discharge machining (EDM) process, and may comprise an arrangement of die pins that form intersecting slots, with the die pins comprising inlet pins and outlet pins. The extrusion can be performed using a hydraulic ram extrusion press, a two stage de-airing single auger extruder, a twin-screw extruder with a die of a die assembly attached to a discharge end, or other suitable devices. In aspects, the ceramic batch mixture can comprise a ceramic-forming mixture comprising a ceramic-forming batch material that may comprise inorganic particles or ceramic particles, or both, and optional one or more pore formers, a rheology modifier, a liquid vehicle, or the like, and combinations thereof. When fired, the batch mixture can be transformed or sintered into a porous ceramic material comprising a porous ceramic structure that is, for example, suitable for exhaust treatment purposes. Accordingly, methods can comprise forming the body 101 extending along the body axis 107, wherein as the body 101 is formed, the plurality of inlet channels 127 and the plurality of outlet channels 129 are formed to extend through the body 101. The plurality of inlet channels 127 and the plurality of outlet channels 129 can be formed to comprise the channel density described herein. Further, the inlet channels 127 and the outlet channels 129 can be formed such that the separating distance 441 can separate adjacent inlet channels and outletchannels. In addition, as the body 101 is formed, methods can further comprise separating an inlet channel (e.g., 127, 401, 403, etc.) from an adjacent outlet channel (e.g., 129, 405, 407, etc.) such that the separating distance 441 is within a range from about 0.25 millimeters to about 0.51 millimeters.

[0059] FIG. 5 illustrates a plot 501 of a mass increase percentage of the honeycomb filter 100, a hydraulic diameter percentage increase AHD of the plurality of outlet channels 129, and a reduction in geometric surface area percentage in the plurality of outlet channels 129 due to an increase in outlet comer radius 439 of the outlet corners 437. The plot 501 is for a honeycomb filter 100 comprising a channel density of 280 cpsi and a wall thickness of 15 mils (0.38 millimeters). The x-axis 503 of the plot 501 represents the ratio of the outlet comer radius 439 to the outlet length 433 (e.g., r / L), ranging from zero to 0.50. The y-axis 505 of the plot 501 represents a percentage, ranging from 0% to 30%.

[0060] A first line 507 represents the mass increase percentage of the honeycomb filter 100 based on different ratios of the outlet comer radius 439 to the outlet length 433. For example, beginning at a ratio of zero (e.g., and with the material, dimensions such as the length 109, the channel density (cpsi), etc. being fixed), the mass increase percentage may slowly increase and may reach an increase of about 5% when the ratio is about 0.22, and may reach an increase of about 10% when the ratio of the outlet corner radius 439 to the outlet length 433 is about 0.30, and may reach an increase of about 20% when the ratio of the outlet comer radius 439 to the outlet length 433 is about 0.42. Accordingly, increasing the ratio of the outlet corner radius 439 to the outlet length 433 can produce a corresponding mass increase percentage of the honeycomb filter 100. In aspects, the ratio of the outlet corner radius 439 to the outlet length 433 can be increased, for example, by increasing the outlet comer radius 439 while the outlet length 433 (e.g., and the outlet width 435) remains fixed or constant. An increase in the mass of the honeycomb filter 100 is beneficial because an increased mass allows for the honeycomb filter to absorb a greater amount of heat during regeneration without damage to the filter 100.

[0061] A second line 509 can represent a hydraulic diameter percentage increase AHD of the plurality of outlet channels 129 based on different ratios of the outlet comer radius 439 to the outlet length 433. For example, beginning at an outlet comer radius 439 to the outlet length 433 ratio of zero, the hydraulic diameter percentage may increase at least until the ratio of the outlet corner radius 439 to the outlet length 433 is about 0.23. From the outlet comer radius 439 to the outlet length 433 ratio of 0.23, the hydraulic diameter percentage may beginto decrease until the outlet comer radius 439 to the outlet length 433 ratio reaches the maximum of 0.5. As illustrated by the second line 509, the rate of change of the hydraulic diameter percentage is smallest when the outlet comer radius 439 to the outlet length 433 ratio is between about 0.20 to about 0.25. An increase in the hydraulic diameter of the outlet channels 129 is beneficial because a greater hydraulic diameter can limit a back pressure increase within the honeycomb filter 100. Accordingly, thermal mass can be added to the honeycomb filter 100 while increasing the hydraulic diameter of the outlet channels 129, thus reducing the likelihood of a back pressure increase.

[0062] A third line 511 can represent a reduction in geometric surface area percentage in the plurality of outlet channels 129 due to an increase in outlet comer radius 439 of the outlet comers 437. For example, beginning at an outlet comer radius 439 to outlet length 433 ratio of zero, the surface area may be reduced at a substantially constant rate, with the surface area reduction being about 11% when the outlet corner radius 439 to the outlet length 433 ratio is 0.25, and about 15% when the outlet comer radius 439 to the outlet length 433 ratio is about 0.35. Reducing the surface area (e.g., due to increasing the outlet corner radius 439) in the plurality of outlet channels 129 has the drawback of increasing back pressure within the honeycomb filter 100. However, even within the reduction of surface area indicated by the third line 511, a back pressure increase can be limited due to the increase in mass of the honeycomb filter 100 (e.g., indicated by the first line 507) and the increase in hydraulic diameter (e.g., indicated by the second line 509). Accordingly, as described herein, the outlet comer radius 439 can be selected to increase the total mass of the honeycomb filter 100 while limiting an increase in the pressure drop through the honeycomb filter 100, such that methods can comprise selecting the outlet corner radius 439 to increase the total mass of the honeycomb filter 100 and limit an increase in the pressure drop through the honeycomb filter 100.

[0063] FIG. 6 illustrates a bar graph 601 comparing soot loadings and pressure drops for different ratios of the outlet comer radius 439 to the outlet length 433 (e.g., r / L). The x-axis 603 of the graph 601 represents different soot levels (e.g., measured in grams / liter) ranging from zero to 5. The y-axis 605 of the graph 601 represents a pressure drop within the honeycomb filter 100, wherein the pressure drop is measured for exhaust flow conditions of 600 kg / hour at 500°C. The bar graph 601 is for a honeycomb filter 100 comprising a channel density of 280 cpsi and a wall thickness of 15 mils (0.38 millimeters), with a length of about 15.2 centimeters and a diameter of about 18 centimeters, and with an initial ash loading of 0 grams / liter. The graph 601 illustrates a first condition 607, in which the ratio of the outletcomer radius 439 to the outlet length 433 is zero, a second condition 609, in which the ratio of the outlet comer radius 439 to the outlet length 433 is 0.25, and a third condition 611, in which the ratio of the outlet corner radius 439 to the outlet length 433 is 0.4. The graph 601 illustrates a comparison of the three different conditions 607, 609, 611 for four different soot loadings along the x-axis 603: a first soot loading 613 of zero grams / liter; a second soot loading 615 of one gram / liter; a third soot loading 617 of three grams / liter; and a fourth soot loading 619 of five grams / liter. The different soot loadings 613, 615, 617, 619 simulate a filter pressure drop performance at different operating stages, such as, for example, a new versus used honeycomb filter 100, before and after regeneration, etc..

[0064] For the first soot loading 613, the three conditions 607, 609, 611 are similar and range from about 7.8 to about 8.6. For the second soot loading 615, the three conditions 607, 609, 611 are similar and range from about 10.4 to about 11.3. For the third soot loading 617, the three conditions 607, 609, 611 are similar and range from about 15.9 to about 16.7. For the fourth soot loading 619, the three conditions 607, 609, 611 are similar and range from about 21.3 to about 22.1. Accordingly, in all cases, the second condition 609 (e.g., outlet corner radius 439 to the outlet length 433 ratio of 0.25) and the third condition 611 (e.g., outlet comer radius 439 to the outlet length 433 ratio of 0.4) showed no penalty or increase in back pressure. In particular, the second condition 609 (e.g., outlet comer radius 439 to the outlet length 433 ratio of 0.25) had the lowest back pressure. The second condition 609 had a mass increase percentage of about 3.4% while the third condition 611 had a mass increase percentage of about 8.8%. The mass increase in the second condition 609 and the third condition 611 lead to a reduction in back pressure. Accordingly, based on these results, an outlet comer radius can be selected for a specific channel geometry to balance the increase in mass of the honeycomb filter 100 while limiting an increase in back pressure. Accordingly, at a minimum, the mass of the honeycomb filter 100 can be increased without negatively impacting the back pressure of the filter 100.

[0065] FIG. 7 illustrates a bar graph 701 similar to the bar graph 601 of FIG. 6.However, while FIG. 6 was based on an initial ash loading of zero grams / liter, the bar graph 701 was based on an initial ash loading of 155 grams. The other conditions for the bar graph 701 in FIG. 7 were identical to the conditions for the bar graph in FIG. 6. For the first soot loading 613, the three conditions 607, 609, 611 are similar and range from about 13.4 to about 14.5. For the second soot loading 615, the three conditions 607, 609, 611 are similar and range from about 21.2 to about 22.3. For the third soot loading 617, the three conditions 607, 609,611 are similar and range from about 37.1 to about 38.1. For the fourth soot loading 619, the three conditions 607, 609, 611 are similar and range from about 53 to about 53.9, e.g., about 54. Accordingly, in all cases, the second condition 609 (e.g., outlet comer radius 439 to the outlet length 433 ratio of 0.25) and the third condition 611 (e.g., outlet comer radius 439 to the outlet length 433 ratio of 0.4) showed no penalty or increase in back pressure. In particular, and similar to the bar graph 601 of FIG. 6, the second condition 609 (e.g., outlet comer radius 439 to the outlet length 433 ratio of 0.25) had the lowest back pressure. The second condition 609 had a mass increase percentage of about 3.4% while the third condition 611 had a mass increase percentage of about 8.8%. The mass increase in the second condition 609 and the third condition 611 lead to a reduction in back pressure.

[0066] FIG. 8 illustrates a bar graph 801 similar to the bar graph 601 of FIG. 6, but with the addition of a fourth condition 803 and a fifth condition 805. The fourth condition 803 is one in which the wall thickness is increased to 15.6 mils (0.40 millimeters) and the outlet comer radius 439 to the outlet length 433 ratio is zero, and the fifth condition 805 is one in which the wall thickness is increased to 16.6 mils (0.42 millimeters) and the outlet corner radius 439 to the outlet length 433 ratio is zero. As illustrated, the fourth condition 803 and the fifth condition 805 exhibit an increased backpressure for all soot loadings along the x-axis 603 compared to the first three conditions 607, 609, 611. Accordingly, by increasing the filter mass of the honeycomb filter 100 by increasing the wall thickness of the porous walls 121 will increase the back pressure within the honeycomb filter 100.

[0067] FIG. 9 illustrates a bar graph 901 similar to the bar graph 801 of FIG. 8.However, while FIG. 8 was based on an initial ash loading of zero grams / liter, the bar graph 901 was based on an initial ash loading of 155 grams. As illustrated, the fourth condition 803 and the fifth condition 805 again exhibit an increased backpressure for all soot loadings along the x-axis 603 compared to the first three conditions 607, 609, 611. Accordingly, increasing the filter mass of the honeycomb filter 100 by increasing the wall thickness of the porous walls 121 may increase the back pressure within the honeycomb filter 100. It is noted that the filter(s) reflected in the bar graphs 801, 901 illustrated in FIGS. 8-9 are designed to match the thermal mass of the filter(s) reflected in the bar graphs 601, 701 illustrated in FIGS. 6-7 by increasing the wall (e.g., web) thickness of the porous walls 121.

[0068] The present application provides several benefits related to the function and performance of a honeycomb filter 100. For example, by providing the outlet channels 129 with outlet comers 437 comprising the outlet comer radius 439, the mass of the honeycombfilter 100 can be increased. However, the inlet channels 127 can comprise the inlet corners 417 with minimized radius or, in some aspects, without a rounded comer (no radius). In this way, the back pressure may not be increased despite the increase in the outlet corner radii 439. The honeycomb filter 100 may be used in high-temperature environments that may pose a risk of damage to a honeycomb filter. However, due to the increase in thermal mass, the risk of damage to the honeycomb filter 100 may be minimized, while also limiting an increase in back pressure.

[0069] It should be understood that while various aspects have been described in detail relative to certain illustrative and specific examples thereof, the present disclosure should not be considered limited to such, as numerous modifications and combinations of the disclosed features are possible without departing from the scope of the following claims.

Claims

CLAIMS1. A honeycomb filter comprising:a body comprising an inlet end, an outlet end, a body axis extending between the inlet end and the outlet end, and a plurality of intersecting porous walls extending along the body axis;a plurality of inlet channels formed by the plurality of intersecting porous walls, the plurality of inlet channels extending along the body axis between the inlet end and the outlet end and comprising inlet openings at the inlet end, the plurality of inlet channels comprising inlet comers comprising an inlet corner radius; anda plurality of outlet channels formed by the plurality of intersecting porous walls, the plurality of outlet channels extending along the body axis between the inlet end and the outlet end and comprising outlet openings at the outlet end, the plurality of outlet channels comprising outlet comers comprising an outlet corner radius, wherein a ratio of the inlet comer radius to the outlet corner radius is less than about 1.

2. The honeycomb filter of claim 1, wherein a separating distance between an inlet channel of the plurality of inlet channels and an adjacent outlet channel of the plurality of outlet channels is within a range from about 0.25 millimeters to about 0.5 millimeters, and wherein the separating distance is a wall thickness of one of the plurality of intersecting porous walls between the inlet channel and the adjacent outlet channel.

3. The honeycomb filter of claim 2, wherein a channel density of the honeycomb filter is within a range from about 250 cells per square inch to about 350 cells per square inch, and wherein the cells are two-dimensional cross-sectional shapes of the plurality of inlet channels and the plurality of outlet channels along a plane perpendicular to the body axis.

4. The honeycomb filter of any one of claims 1-3, wherein an outlet length of an outlet channel is defined between opposing parallel outlet walls of the plurality of intersecting porous walls forming the outlet channel, and a ratio of the outlet corner radius to the outlet length is within a range from about 0.2 to about 0.4.

5. The honeycomb filter of claim 4, wherein the ratio of the outlet comer radius to the outlet length is within a range from about 0.2 to about 0.3.

6. The honeycomb filter of any one of claims 1-5, wherein an inlet length of an inlet channel is defined between opposing parallel inlet walls of the plurality of intersecting porous walls forming the inlet channel, and a ratio of the inlet comer radius to the inlet length is less than about 0.1.

7. The honeycomb filter of claim 6, wherein the ratio of the inlet comer radius to the inlet length is less than about 0.05.

8. A honeycomb filter comprising:a body comprising an inlet end, an outlet end, a body axis extending between the inlet end and the outlet end, and a plurality of intersecting porous walls extending along the body axis;a plurality of inlet channels formed by the plurality of intersecting porous walls, the plurality of inlet channels extending along the body axis between the inlet end and the outlet end and comprising inlet openings at the inlet end, the plurality of inlet channels comprising inlet comers comprising an inlet corner radius and an inlet length between opposing parallel inlet walls of the plurality of intersecting porous walls, wherein a ratio of the inlet corner radius to the inlet length is less than about 0.05; anda plurality of outlet channels surrounded by the plurality of intersecting porous walls, the plurality of outlet channels extending along the body axis between the inlet end and the outlet end and comprising outlet openings at the outlet end, the plurality of outlet channels comprising outlet comers comprising an outlet corner radius and an outlet length between opposing parallel outlet walls of the plurality of intersecting porous walls, wherein a ratio of the outlet comer radius to the outlet length is within a range from about 0.2 to about 0.4.

9. The honeycomb filter of claim 8, wherein a separating distance between an inlet channel of the plurality of inlet channels and an adjacent outlet channel of the plurality of outlet channels is within a range from about 0.25 millimeters to about 0.5 millimeters, and wherein the separating distance is a wall thickness of one of the plurality of intersecting porous walls between the inlet channel and the adjacent outlet channel.

10. The honeycomb filter of claim 9, wherein a channel density is within a range from about 250 cells per square inch to about 350 cells per square inch, and wherein the cells are two-dimensional cross-sectional shapes of the plurality of inlet channels and the plurality of outlet channels along a plane perpendicular to the body axis.

11. The honeycomb filter of claim 8, wherein the ratio of the outlet comer radius to the outlet length is within a range from about 0.2 to about 0.3.

12. A method of manufacturing a honeycomb filter comprising:forming a body extending along a body axis between an inlet end and an outlet end, the body comprising:a plurality of intersecting porous walls extending along the body axis;a plurality of inlet channels extending along the body axis between the inlet end and the outlet end, the plurality of inlet channels comprising inlet openings at the inlet end and inlet comers comprising an inlet corner radius; anda plurality of outlet channels comprising outlet corners comprising an outlet comer radius, wherein a ratio of the inlet corner radius to the outlet comer radius is less than about 1.

13. The method of claim 12, further comprising selecting the outlet comer radius to increase a total mass of the honeycomb filter without increasing a pressure drop through the honeycomb filter.

14. The method of claim 12, further comprising separating an inlet channel of the plurality of inlet channels from an adjacent outlet channel of the plurality of outlet channels such that a separating distance between the inlet channel and the adjacent outlet channel is within a range from about 0.25 millimeters to about 0.5 millimeters, and wherein the separating distance is a wall thickness of one of the plurality of intersecting porous walls between the inlet channel and the adjacent outlet channel.

15. The method of any one of claims 12-14, wherein the plurality of inlet channels and the plurality of outlet channels are formed such that a channel density of the honeycomb filteris within a range from about 250 cells per square inch to about 350 cells per square inch, and wherein the cells are two-dimensional cross-sectional shapes of the plurality of inlet channels and the plurality of outlet channels along a plane perpendicular to the body axis.

16. The method of any one of claims 12-15, wherein the plurality of inlet channels comprises an inlet length of an inlet wall of the plurality of intersecting porous walls forming one of the plurality of inlet channels, and a ratio of the inlet corner radius to the inlet length is less than about 0.05.

17. The method of claim 16, wherein the plurality of outlet channels comprise an outlet length of an outlet wall of the plurality of intersecting porous walls forming one of the plurality of outlet channels, and a ratio of the outlet comer radius to the outlet length is within a range from about 0.2 to about 0.4.

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