WO2019168017A1

WO2019168017A1 - Exhaust purification structure

Info

Publication number: WO2019168017A1
Application number: PCT/JP2019/007525
Authority: WO
Inventors: 篤人中村; 加藤　正; 隆時南
Original assignee: ニチダイフィルタ株式会社
Priority date: 2018-02-28
Filing date: 2019-02-27
Publication date: 2019-09-06
Also published as: JP2021071050A

Abstract

[Problem] To provide an exhaust purification structure that enables both a reduction in pressure loss and securement of a large exhaust circulation area, without changing the opening diameter of an opening end of an exhaust pipe. [Solution] An exhaust purification structure according to the present invention comprises a hollow space P formed by a part or the whole of a catalyst carrier 1 provided in the middle of an exhaust flow path, wherein inner and outer surfaces of a region of least 50% or more in the hollow space P enable ventilation in a radial direction.

Description

Exhaust purification structure

The present invention relates to an exhaust purification structure capable of efficiently purifying exhaust gas from an internal combustion engine.

For example, in Patent Document 1, a gasket portion interposed between each combustion chamber of an internal combustion engine and each branch pipe of a manifold is provided with a cylindrical portion to be inserted into the branch pipe, and a catalyst layer is formed on the inner and outer surfaces of the cylindrical portion. The structure which provides is disclosed.

In the configuration of the above-mentioned patent document 1, since a large flow opening area of the exhaust gas can be secured in the thrust direction, the pressure loss (hereinafter referred to as pressure loss) can be reduced, but the catalyst layer is parallel to the exhaust gas flow direction ( Since the exhaust gas that contacts the catalyst layer is purified, the exhaust gas that flows through the central portion of the cylinder portion in the exhaust flow channel does not contact the catalyst layer, and as a result, the exhaust gas that is not purified. As a result, there is a problem that the purification efficiency as viewed from the whole displacement is poor.

In order to reduce the pressure loss, it is only necessary to increase the flow area of the exhaust. However, due to restrictions on the size of the device, it cannot be increased without limit, and reducing the pressure loss is a large purification device structure in the exhaust pipe configuration. There was a problem of inviting.

Japanese Patent Laid-Open No. 2001-50043

The problem to be solved by the present invention is that in Patent Document 1, since the catalyst layer is provided on a surface parallel to the flow direction of the exhaust gas, the exhaust gas flowing through the central portion of the exhaust flow channel is not purified, and the exhaust gas purification efficiency is improved. The bad thing is that, due to the structure of the purification device, it is not possible to secure an infinitely large flow area of exhaust gas even if the pressure loss is reduced.

In order to solve the above problems, the present invention forms a hollow space by a part or all of the catalyst carrier provided in the middle of the exhaust flow path, and the inner and outer surfaces of at least 50% or more of the hollow space are in the radial direction. The main feature is that it can be ventilated.

In the present invention, the hollow space provided in the middle of the exhaust passage is formed by a part or all of the catalyst carrier, and the inner and outer surfaces of at least 50% or more of the hollow space can be vented in the radial direction. The contact diameter between the catalyst and the exhaust can be ensured widely with the opening diameter of the open end of the pipe as it is, and therefore it is possible to achieve both a reduction in pressure loss and a wide flow area.

In addition, the present invention can achieve both a reduction in pressure loss and a wide flow area, and the entire amount of exhaust gas passes through the hollow space of the catalyst carrier and comes into contact with the catalyst, thereby improving exhaust purification efficiency. .

It is a perspective view which shows the Example structure of the exhaust gas purification structure of this invention. FIG. 2 is an end view taken along line AA in FIG. 1. (A) The figure which shows the modification of a catalyst carrier in the exhaust purification structure of this invention, (b) is an end elevation which shows an attachment condition. (A) The figure which shows the modification of a catalyst carrier in the exhaust purification structure of this invention, (b) is an end elevation which shows an attachment condition. (A) The figure which shows the modification of a catalyst carrier in the exhaust purification structure of this invention, (b) is an end elevation which shows an attachment condition. (A) The figure which shows the modification of a catalyst carrier in the exhaust purification structure of this invention, (b) is an end elevation which shows an attachment condition. It is a figure which shows the modification of the exhaust gas purification structure of this invention. It is a figure which shows the modification of the exhaust gas purification structure of this invention. It is a figure which shows the modification of the exhaust gas purification structure of this invention.

It is an object of the present invention to reduce the pressure loss, secure a wide exhaust flow area, improve the exhaust purification efficiency, and prevent the structure from becoming large when realizing these. A hollow space is formed by a part or all of the catalyst carrier provided in the middle, and the inner and outer surfaces of at least 50% or more of the hollow space have a structure that allows ventilation in the radial direction.

Here, the definition of the thrust direction and the radial direction in the present invention will be described. First, the thrust direction in the present invention refers to the inflow at the “connecting portion” between the exhaust pipe and the hollow space on the exhaust upstream side of the hollow space, centering on the hollow space formed by part or all of the catalyst carrier. Direction, on the (purified) exhaust downstream side of the hollow space, means the outflow direction at the “connecting portion” between the hollow space and the downstream pipe. On the other hand, the radial direction means a concentric direction around the thrust axis with respect to the thrust direction.

Further, in the present invention, the catalyst support is configured such that the catalyst is supported on a porous body obtained by laminating and sintering a plurality of metal meshes, or a porous body obtained by sintering a single-layer metal mesh material. May be adopted. By doing so, the degree of freedom of forming by cutting and bending is increased, and it is possible to adjust the contact area with the exhaust and the pressure loss by changing the number of wire meshes used.

Furthermore, the present invention may be configured such that, in the above configuration, a deflecting member for deflecting the exhaust in the thrust direction inside the hollow in the radial direction is provided. By doing so, even if the ventilation efficiency in the radial direction is low due to the shape of the hollow space, this can be improved.

Further, the present invention further increases the contact area between the exhaust gas and the catalyst by providing the deflecting member as a catalyst carrier in the configuration in which the deflecting member for deflecting the exhaust in the thrust direction of the hollow space in the radial direction is provided. be able to.

Furthermore, the present invention provides a deflecting member that deflects the exhaust in the thrust direction of the hollow space in the radial direction, and if the deflecting member blocks the flow in the thrust direction in the hollow space, Exhaust gas to be circulated can be deflected substantially in the radial direction.

Further, the present invention may have a structure in which the end opposite to the end of the catalyst carrier connected to the exhaust pipe is not constrained in the above configuration. By doing so, the thermal expansion and contraction of the catalyst carrier occur at the unconstrained end, so that, for example, even under high temperature conditions near the internal combustion engine, the mounting structure It is not necessary to take into account fluctuations in thermal expansion and contraction.

Furthermore, the present invention may have a structure in which the end opposite to the end of the catalyst carrier connected to the exhaust pipe is supported so as to allow thermal expansion and contraction of the catalyst carrier in the above configuration. In this way, for example, it is possible to save time and effort to design and install the thermal expansion / shrinkage of the catalyst carrier even when the temperature is relatively close to the internal combustion engine. The support of the catalyst carrier is not released.

Hereinafter, specific examples of the exhaust purification structure of the present invention will be described with reference to the drawings. Hereinafter, based on the first embodiment shown in FIG. 1 and FIG. 2, only the changed components will be described in the second and subsequent embodiments.

Example 1
The exhaust purification structure in Example 1 uses a cylindrical catalyst carrier 1 in which a catalyst material is supported on a porous body obtained by sintering a material in which a plurality of metal meshes are laminated (the catalyst carrier 1 is a single unit). The catalyst may be supported on a porous body obtained by sintering a wire mesh material of a layer).

The catalyst carrier 1 is a hollow space P in which a cylindrical interior communicates with the exhaust pipe 2, and a deflection member 3 is provided on a peripheral surface defining the hollow space P to block the flow of exhaust in the thrust direction, which will be described later. About 90% of the area excluding the area is an area capable of venting in the radial direction.

The catalyst carrier 1 is connected by fitting one end in the axial direction to the open end of the exhaust pipe 2 and blocking the flow in the thrust direction in the hollow space P to the other end to change the flow path in the radial direction. A deflection member 3 is provided. The open end of the exhaust pipe 2 is fitted and connected to the connection pipe 4 having a larger diameter than the exhaust pipe 2 in a state where one end of the hollow space P is connected.

In the exhaust purification structure of the present invention, the exhaust gas flowing into the hollow space P flows outside the hollow space P after contacting the radial catalyst, and in the first embodiment, the deflection member 3 blocks the flow in the thrust direction. As a result, the flow area of the exhaust gas is ensured to reduce the pressure loss, and the contact area between the catalyst carrier 1 and the exhaust gas is also secured to improve the purification efficiency.

In Example 1, one end portion of the catalyst carrier 1 that forms the hollow space P is fitted to the open end portion of the exhaust pipe 2 by welding. As for the attachment to the exhaust pipe 2, a simple and reliable method may be adopted as appropriate according to the attachment position.

The deflecting member 3 uses the other end portion of the cylindrical catalyst carrier 1 as a plate-like member having no air permeability (a bottom portion 3a described later). For example, the deflecting member 3 according to the first embodiment has one end opened and the other end. It is composed of a cylindrical main body 3A having a bottom 3a at the end and a shallow depth. The deflecting member 3 is provided with a fixed arm portion 3b for attaching the main body 3A to the inner surface of the connecting pipe 4 on the peripheral surface thereof.

The deflection member 3 is not in contact with the inner surface of the bottom 3a of the main body 3A and the other end of the catalyst carrier 1 forming the hollow space P, and there is a gap that allows thermal expansion and contraction of the catalyst carrier 1. In addition, the inner peripheral surface of the main body 3A and the outer peripheral surface of the other end of the catalyst carrier 1 are stacked, that is, the catalyst carrier 1 is externally fitted as an inner cylinder.

By doing so, the axial extension due to thermal expansion of the other end of the catalyst carrier 1 is allowed, and the other end of the catalyst carrier 1 forming the hollow space P is in the exhaust pipe 2 and the connection pipe 4. It can be fixed without shaking. Furthermore, in order to ensure a wide exhaust contact area, the catalyst carrier 1 can be securely fixed in the connecting pipe 4 even if the axial dimension of the catalyst carrier 1 is elongated.

The connection between the exhaust pipe 2 and the connection pipe 4 is not particularly limited. Of course, the exhaust pipe does not flow backward in the direction of the exhaust pipe 2 in the connection pipe 4 or leaks outside. The connecting pipe 4 is required to have a size that can cover a part of the end of the exhaust pipe 2 and the cylindrical catalyst carrier 1.

Further, in the exhaust purification structure, if the catalyst carrier 1 is provided in the open end of the exhaust pipe 2 in the open end of the exhaust pipe 2 where the connection pipe 4 does not exist at the downstream end of the exhaust flow path in the middle of the exhaust flow path, the internal combustion engine The structure for exhaust gas purification can be easily attached from the outside of the structure.

(Example 2)
Examples 2 to 5 below show modifications of the shape of the catalyst carrier 1 that mainly forms the hollow space P. Example 2 shown in FIG. 3 is as follows. Hereinafter, the points different from the first embodiment will be mainly described. The catalyst carrier 1 forming the hollow space P has a conical shape and is different from the first embodiment in that a flange portion 1a is formed at the lower end portion thereof as shown in FIG. In addition, the second embodiment is different from the first embodiment in that a flange 2a is formed at the open end of the exhaust pipe 2 and the deflection member 3 and the fixed arm portion 3b are omitted.

The flange 1a of the catalyst carrier 1 is interposed between the flange 2a of the exhaust pipe 2 and the ring member 2b inserted from the upper end of the catalyst carrier 1. When the flange 2a and the ring member 2b are brought into close contact with the bolt and nut, the flange 1a of the catalyst carrier 1 is pressurized from the front and back to increase the density (of the metal mesh) and crush the mesh of the metal mesh. By doing so, the exhaust gas does not leak from the close contact portion between the flange 2a and the ring member 2b, and it is securely attached.

(Example 3)
Example 3 shown in FIG. 4 is as follows. Hereinafter, the points different from the first embodiment will be mainly described. As shown in FIG. 4 (a), the catalyst carrier 1 forming the hollow space P is a cylindrical body whose upper part is a semi-spherical shape, and the flange part 1a is formed at the lower end part. Different from Example 1. Other differences from the first embodiment are the same as those of the second embodiment, and thus the description thereof is omitted.

(Example 4)
Example 4 shown in FIG. 5 is as follows. Hereinafter, the points different from the first embodiment will be mainly described. The catalyst carrier 1 has a cylindrical shape as shown in FIG. 5 (a) and blocks the flow in the thrust direction on the upper end surface thereof (the cylindrical main body having a shallow depth shown in FIGS. 1 and 2 in the first embodiment). Example 1 is that a plate-like deflecting member 3 having only a bottom part 3a (without 3A) is provided, a flange part 1a is formed at a lower end part thereof, and a fixing arm part 3b is omitted. And different. Other differences from the first embodiment are the same as those of the second embodiment, and thus the description thereof is omitted.

(Example 5)
Example 5 shown in FIG. 6 is as follows. Hereinafter, the points different from the first embodiment will be mainly described. The catalyst carrier 1 has a cylindrical shape as shown in FIG. 6A, and is formed of the same catalyst carrier as the catalyst carrier 1 that is recessed at one end surface toward the other end surface direction (exhaust pipe 2 direction in the drawing). The deflecting member 3 is provided, the flange portion 1a is formed at the lower end, and the fixed arm portion 3b is omitted from the first embodiment. Other differences from the first embodiment are the same as those of the second embodiment, and thus the description thereof is omitted.

The above Examples 2 to 5 are modification examples of the shape of the catalyst carrier 1 that mainly forms the hollow space P, and in any case, the hollow space P is formed by a part or all of the catalyst carrier 1, and this hollow Since 50% or more of the space P can be vented in the radial direction, the same effects as those of the first embodiment can be obtained. The shape of the hollow space P is not limited to the above as long as the condition is satisfied.

In Examples 2 to 5, since the flange portion 1a of the catalyst carrier 1 that forms the hollow space P is sandwiched between the flange 2a of the exhaust pipe 2 and the ring member 2b, the catalyst that forms the hollow space P is used. The carrier 1 and the exhaust pipe 2 can be firmly attached without exhaust from leaking out of the flow path from the connection portion.

(Example 6)
Examples 6 to 9 below show examples of attaching the catalyst carrier 1 mainly in the exhaust passage. Example 6 shown in FIG. 7 is as follows. Hereinafter, the points different from the first embodiment will be mainly described. The catalyst carrier 1 forming the hollow space P in the sixth embodiment is formed in a cylindrical shape, and blocks the flow in the thrust direction of the exhaust gas flowing into the hollow space P at the end opposite to the end on the connection side. The difference from Embodiment 1 is that the deflecting member 3 having only the bottom portion 3a is provided (does not have the shallow cylindrical main body 3A shown in FIGS. 1 and 2 in Embodiment 1).

Further, Example 6 differs from the configuration provided in the exhaust pipe 2 in Example 1 in that the fixed arm portion 3b is omitted and the catalyst carrier 1 is provided at the inflow end portion of the downstream pipe 5. . That is, the sixth embodiment is on the (purified) exhaust downstream side of the hollow space P, and the outflow direction at the “connecting portion” between the hollow space P and the downstream pipe 5 is the thrust direction. Is different. In the sixth embodiment, exhaust gas filling the connection pipe 4 flows into the hollow space P of the catalyst carrier 1 into the downstream pipe 5, where it is purified and exhausted to the downstream pipe 5.

(Example 7)
The catalyst carrier 1 that forms the hollow space P in Example 7 shown in FIG. 8 is cylindrical, and the cylindrical shaft ends are respectively connected to the exhaust pipe 2, and the deflection member 3 and the fixed arm portion 3b are omitted. However, the configuration differs from that of the first embodiment.

In Example 7, exhaust gases from the exhaust pipes 2 provided in opposite directions are collected in the hollow space P, collected and purified by the catalyst carrier 1, and exhausted to the downstream pipe 5 through the connection pipe 4. In Example 7, the downstream pipe 5 may be the connecting pipe 4.

(Example 8)
The catalyst carrier 1 that forms the hollow space P in the eighth embodiment shown in FIG. 9 has a cylindrical shape and blocks the flow in the thrust direction at the end opposite to the end on the connection side (see FIG. 1 in the first embodiment). The difference from Embodiment 1 is that the deflecting member 3 having only the bottom portion 3a (not including the cylindrical main body 3A having a shallow depth shown in FIG. 2) is provided.

In the eighth embodiment, the fixed arm 3b is omitted, and the catalyst carrier 1 is provided at each of the exhaust ends of the exhaust pipe 2 branched into two branches. This is different from the configuration provided in FIG. In Example 8, since the catalyst carrier 1 is provided at each of the exhaust end portions branched into two portions (branched into a plurality of portions), the exhaust efficiency is improved. In Example 8, the downstream pipe 5 may be the connecting pipe 4.

The above Examples 6 to 8 are modifications mainly relating to the attachment of the catalyst carrier 1 that forms the hollow space P in the exhaust flow path, but in any case, the hollow space P is partially or entirely in the catalyst carrier 1. Since 50% or more of the hollow space P can be vented in the radial direction, the same effects as those of the first embodiment can be obtained. In addition, the position where the catalyst carrier 1 that forms the hollow space P in the exhaust passage by the part or the whole is not limited to the above as long as the conditions of the present invention are satisfied.

DESCRIPTION OF SYMBOLS 1 Catalyst support body 1a Flange part 2 Exhaust pipe 2a Flange 2b Ring member 3 Deflection member 3A Main body 3a Bottom part 3b Fixed arm part P Hollow space

Claims

An exhaust purification structure characterized in that a hollow space is formed by a part or all of the catalyst carrier provided in the middle of the exhaust flow path, and the inner and outer surfaces of at least 50% or more of the hollow space can be ventilated in the radial direction. .
The catalyst carrier is a porous body obtained by laminating and sintering a plurality of metal meshes, or a porous body obtained by sintering a single-layer metal mesh material. The exhaust purification structure described.
3. The exhaust gas purification structure according to claim 1, further comprising a deflecting member for deflecting exhaust gas in a thrust direction of the hollow space in a radial direction.
4. The exhaust gas purification structure according to claim 3, wherein the deflecting member is a catalyst carrier.
4. The exhaust gas purification structure according to claim 3, wherein the deflection member blocks the flow in the thrust direction in the hollow space.
The exhaust purification structure according to any one of claims 1 to 5, wherein the end opposite to the end of the catalyst carrier on the side connected to the exhaust pipe is not constrained.
The end of the catalyst carrier opposite to the end connected to the exhaust pipe is supported so as to allow thermal expansion and contraction of the catalyst carrier. Exhaust purification structure.