Aftertreatment component of an exhaust aftertreatment system

Abstract

Aftertreatment component (100) of an exhaust aftertreatment system, comprising: a post-treatment substrate (110); a compressible material (120) formed from a thermoset, which is bonded to an outer surface of the post-treatment substrate; and a catalyst washcoat applied to the post-treatment substrate, wherein the catalyst washcoat is applied to the post-treatment substrate after the compressible material has been bonded to the post-treatment substrate.

Description

BACKGROUND

[0001] Known catalyst substrate articles for engine aftertreatment systems contain a catalyst substrate material wrapped in a ceramic fiber mat, which is then enclosed by a metal casing or housing. The catalyst substrate material can be a ceramic material such as cordierite or silicon carbide. Catalyst components are known to be damaged by thermal stress, for example, by temperature expansion differences between the substrate material and the housing material. The use of a ceramic fiber mat allows for substrate expansion within the housing, but incurs considerable costs, is complex to manufacture, and wastes space within the catalyst housing that cannot be used for active gas treatment. Therefore, further technical developments in this area are desirable.

[0002] From WO 01 / 00304 A1 a catalyst for an exhaust system of an internal combustion engine is known, wherein the catalyst comprises a monolithic substrate which is surrounded by a combination of a corrugated wire mesh and a material which swells under the influence of heat in order to be positioned and held within the outer shell of the catalyst.

[0003] From DE 10 2005 024 124 A1 a method and a device for the production of monolithic catalysts by applying a washcoat suspension to a honeycomb body having channels are known.

[0004] For further background information, please refer to the document published under US 2018 / 0283252 A1. SUMMARY

[0005] The invention described herein relates to a post-treatment component according to the features of independent claim 1. Optional embodiments are defined by the dependent claims. These and other features, together with the organization and nature of its operation, will become clear from the following detailed description together with the accompanying drawings, wherein identical elements in the various drawings described below are numbered identically. BRIEF DESCRIPTION OF THE IMAGES Fig. Figure 1 is a cross-sectional view of a post-treatment component, which has been constructed according to different designs. Fig. Figure 2 is a flowchart with an exemplary process for the production of a post-treatment component according to various designs. DESCRIPTION OF THE ILLUSTRATIVE EXECUTION FORMS

[0006] For the purpose of a better understanding of the principle of the invention, reference is now made to the embodiments shown in the drawings, and specific terms are used for their description. It is understood, however, that this is not intended to limit the scope of the invention; any changes and further modifications of the embodiments shown, and all further applications of the principles of the invention as shown here, as they would occur to a person skilled in the art in the field to which the invention relates, are taken into account here.

[0007] Referring to Fig. Figure 1 shows an aftertreatment component 100 of an exhaust aftertreatment system, including a cylindrical aftertreatment substrate material 110 and a compressible material 120 connected to the cylindrical aftertreatment substrate material 120. It should be noted that corrugated materials are specifically mentioned at various points here; the structure is also applicable to other compressible materials as mentioned herein. It should therefore be clear that the statements contained herein relating to corrugated materials should also be understood as referring to other, non-corrugated compressible materials. The outer surface of the compressible material 120 is defined by a housing or casing 130.The cylindrical shape of the post-treatment substrate material 110 should be understood in a broad sense and can refer to a cylindrical shape having any cross-section, including variable or changing cross-sections. Examples and non-restrictive cross-sections include circular (as in ). Fig. (shown), square, elliptical, or rectangular cross-sections. The post-treatment component 100 can form part of any post-treatment component as understood in the prior art. In certain embodiments, the post-treatment component can be a substrate for an oxidation catalyst, a particle filter, a NOx treatment catalyst (e.g., NOx adsorber and / or selective reduction catalyst (SRC)), an ammonia oxidation catalyst, a three-way catalyst, and / or a four-way catalyst.

[0008] A particulate filter, if present, can be a partial-flow or full-flow component (e.g., flow-through or wall flow). All aftertreatment components can be catalyzed or uncatalyzed. One example includes a catalyzed aftertreatment component subject to a specified operating temperature range exceeding several hundred degrees Celsius—for example, a Tmax minus Tmin of 200 °C, 300 °C, 400 °C, 500 °C, or more. In another example, the maximum temperature of the aftertreatment component exceeds 500 °C, 600 °C, 700 °C, or more. One example includes a catalyzed diesel particulate filter (DPF), and another or alternative example includes a diesel oxidation catalyst and / or a block catalyst.A block catalyst such as the one used here should, generally speaking, be understood to include all catalysts that have been specifically positioned to maintain exhaust gas temperatures at the catalyst location, and may include physical proximity to the engine (e.g., moving the catalyst towards or even in front of a turbocharger) and / or thermal proximity to the engine (e.g., insulating the exhaust manifold, turbocharger and / or the exhaust pipe between the turbocharger and the aftertreatment component).

[0009] In various embodiments, the compressible material essentially surrounds the outer surface of the post-treatment substrate. The compressible material can enclose a variety of other materials. Such compressible materials can be designed with a flexible cell structure or to enclose polymer matrices. Examples of such materials include, but are not limited to, foams and elastomers. Polymer materials used for the compressible material can be either thermosets or thermoplastics and can be organic (e.g., polyimides, polysulfones, polyetheretherketone, perfluoroelastomers, etc.), inorganic (e.g., polysiloxanes), or organo-inorganic hybrids (e.g., carbonanylenesiloxanes). The term "thermoset" refers to a material that does not melt or remelt after curing.Besides their compressibility, such materials may also tend to be essentially non-displaceable. High-temperature plastics and various rubberized materials (i.e., flexible, stretchable polymer-coated textiles and the like) can be particularly useful in this respect, although the precise type of materials is not necessarily limited to the above.

[0010] The compressible materials referred to here can be bonded to the ceramic substrate via a variety of processes, including co-extrusion (as described below), resin injection, or by coating a polymer onto the outer surface of a ceramic substrate. Alternatively, a prepolymer or partially polymerized material can be applied to the outer surface of a ceramic substrate, after which polymerization can be completed with the application of heat, UV light, and / or a chemical accelerator, either before or after the preservation process.

[0011] The compressible material can perform a variety of functions for the post-treatment component. For example, it can hold the post-treatment substrate (e.g., the catalyst in certain applications) in place and in the correct position, and it can also protect the post-treatment substrate from potential damage caused by environmental conditions or deposits outside the post-treatment component. The compressible material can also cushion the expansion and contraction of the post-treatment substrate, for example, due to large temperature fluctuations.

[0012] An example system comprises a post-treatment component with an outer shell, the outer shell defining the compressible material. Where an outer skin is present in certain embodiments, it can at least partially compress the compressible material and / or apply a certain closing force to the substrate through the compressible material. An example system includes the compressible material under tension and / or (if corrugated materials are used) at least partially compressed corrugations. For example, if the corrugated material is used as the compressible material, the fully corrugated material may be slightly smaller than the substrate.Where the compressible material forms a continuous enclosure (either originally shaped that way, or added later, for example, by welding), the slightly smaller compressible material can be stretched to adapt to the substrate, thus putting the compressible material under tension and / or providing a selected closing pressure or force on the substrate.

[0013] The following schematic process description provides an illustrative embodiment of the procedures for manufacturing and / or using a post-treatment component. The processes shown are to be understood as merely exemplary, and they can be combined or separated, added or omitted, and partially or completely rearranged, unless expressly stated otherwise herein. Certain of the depicted processes can be implemented using a computer running a computer program product on a durable, computer-readable storage medium, wherein the computer program product contains instructions that allow the computer to execute one or more of the processes or to issue commands to other devices to execute one or more of the processes.

[0014] An example procedure for the production and / or use of the post-treatment component is described in Fig. 2 shown. At 200 in Fig. 2. A process is carried out to direct a heated exhaust gas stream into a catalyst substrate and to thermally expand the catalyst substrate into a compressible material that defines the catalyst substrate. At 205, the compressible material is at least partially compressed. If the compressible material contains waves, at least partial compression of the waves includes any process that compresses at least a portion of the waves. Such processes may include a process that deforms one or more waves from their original shape (plastically, permanently, or mixed), a process that makes a vertical dimension of a wave shorter than an original vertical dimension, a process that makes a horizontal dimension of a wave wider or narrower than an original horizontal dimension, and / or a process that releases a certain potential energy (e.g.,(through a spring action) in one or more shafts. As used for the purpose of determining shaft compression, the term vertical refers to a dimension in the direction of a radial line from the center of the post-treatment component, while horizontal refers to a dimension parallel to the circumference of the post-treatment component.

[0015] At 210 in Fig. 2. A process is carried out to enclose the compressible material in an outer shell that defines the compressible material. "Define," as used here, should be understood in a broad sense. An example of a first object defining a second object includes the case where a second object is positioned entirely within the geometric boundaries of the first object. Another example of a first object defining a second object includes the case where substantial parts of the second object are positioned entirely within the geometric boundaries of the first object.

[0016] At 215 in Fig. In Figure 2, the catalyst substrate is positioned within the compressible material. In Figure 220, a catalyst washcoat is applied to the catalyst substrate after positioning. The use of a compressible material allows for the application of a catalyst washcoat after the corrugated material has been applied. Accordingly, further manufacturing processes can be activated and simplified, and / or the surface of the compressible material can be included in the catalytically active area of ​​the post-treatment component. All these options distinguish a compressible material from the use of a ceramic fiber mat. In Figure 225, at least a portion of the catalyst washcoat can be applied to one substrate side of the compressible material.

[0017] As an alternative to the one in Fig.In the process shown in Figure 2, it is also possible to form a combination of catalyst substrate and compressible material through a coextrusion process. In coextrusion, several materials are passed through one or more dies to simultaneously produce the catalyst substrate and the compressible materials. In some reactions, the catalyst substrate and the compressible material are coextruded through the same die. In other reactions, two dies can be used together for the separate coextrusion of the catalyst substrate and the compressible material.

[0018] As can be seen from the illustrations and the text above, a number of embodiments are considered in accordance with the present disclosure.

[0019] One example group of embodiments is a system comprising a cyclic post-treatment substrate material and a corrugated material connected to the cylindrical post-treatment substrate material. An example system includes the post-treatment component, which further comprises a catalyst washcoat applied to the substrate material and may additionally include the catalyst washcoat applied to the substrate side of the corrugated material.

[0020] An example system comprises the post-treatment component with an outer shell, wherein the outer shell defines the corrugated material and at least partially compresses the corrugated material and / or applies a defined clamping force to the substrate through the corrugated material. An example system comprises the compressible material under tension and / or at least partially compressed corrugations. In certain embodiments, the system comprises corrugated material that applies a defined clamping force to the substrate.

[0021] One example group of embodiments is a method that includes introducing a heated exhaust gas stream into a catalyst substrate, thermally expanding the catalyst substrate into a corrugated material that defines the catalyst substrate, and thereby at least partially compressing the corrugations of the corrugated material. Certain further embodiments of the method are also described below. One example method includes confining the corrugated material within an outer shell that defines the corrugated material. Another example method includes positioning the catalyst substrate within the corrugated material and applying a catalyst washcoat to the catalyst substrate after its positioning.

[0022] Another example method also includes the application of at least part of the catalyst washcoat to the substrate side of the corrugated material.

[0023] While the invention has been shown and described in detail in the drawings and the preceding description, this is for illustrative purposes only and not to be considered limiting, since it is self-evident that only some exemplary embodiments have been shown and described. It will be clear to those skilled in the art that many modifications to the exemplary embodiments are possible without substantially departing from this invention. Accordingly, all such modifications are to be considered included within the scope of this disclosure, as defined in the following claims.

[0024] When reading the claims, it should be assumed that the use of words such as "a", "a", "at least a / an", or "at least in part" does not imply any intention to limit the claim to only one subject matter, unless expressly stated otherwise in the claim. Where the terms "at least in part" and / or "partially" are used, the subject matter may include a part and / or the entire subject matter, unless expressly stated otherwise.

Claims

[1] Aftertreatment component (100) of an exhaust aftertreatment system, comprising: a post-treatment substrate (110); a compressible material (120) formed from a thermoset, which is bonded to an outer surface of the post-treatment substrate; and a catalyst washcoat applied to the post-treatment substrate, wherein the catalyst washcoat is applied to the post-treatment substrate after the compressible material has been bonded to the post-treatment substrate. [2] Post-treatment component (100) according to claim 1, wherein the catalyst washcoat is applied to a substrate side of the compressible material (120). [3] Post-treatment component (100) according to claim 1 or 2, further comprising an outer shell (130), the outer shell defining the compressible material (120). [4] Post-treatment component (100) according to claim 3, wherein the outer shell (130) compresses the compressible material (120) at least partially against the post-treatment substrate (110). [5] Post-treatment component (100) according to claim 4, wherein the outer shell (130) applies a certain closing force to the post-treatment substrate (110) through the compressible material (120). [6] Post-treatment component (100) according to any one of claims 1 to 5, wherein the compressible material (120) applies a specific closing force to the post-treatment substrate (110). [7] Post-treatment component (100) according to any one of claims 1 to 6, wherein the post-treatment substrate (110) and the compressible material (120) are simultaneously formed and joined together by co-extrusion.

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