JP2023066830A - Exhaust emission control device - Google Patents

Abstract

To provide an exhaust emission control device capable of suppressing deterioration of emission control performance and damage of a catalyst.SOLUTION: An exhaust emission control device includes: a cylindrical catalyst case 31 to which exhaust gas of an internal combustion engine is introduced; a catalyst 32 stored in the catalyst case 31; a buffer member 33 coming into contact with an outer surface of the catalyst 32 and an inner peripheral surface of the catalyst case 31 to hold the catalyst 32; and a downstream cone 4 coupled to the downstream side in the exhaust gas flowing direction of the catalyst case 31. An end 42 on the upstream side in the exhaust gas flowing direction of the downstream cone 4 is inserted into the catalyst case 31 and comes into contact with the buffer member 33 or faces the buffer member 33 via an air gap in the axial direction of the catalyst case 31. In the radial direction of the catalyst case 31, an air gap is provided between the catalyst 32 and the end 42 of the downstream cone 4.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to an exhaust gas purification device.

2. Description of the Related Art In an exhaust gas purifier that uses a catalyst to purify exhaust gas from an internal combustion engine of an automobile, the catalyst is housed in a catalyst case via a buffer member (see Patent Documents 1 and 2).

Japanese Utility Model Laid-Open No. 48-085011 JP-A-05-163939

In a conventional exhaust gas purifying device, in order to suppress the displacement of the catalyst to the downstream side due to the flow direction of the exhaust gas, the downstream cone connected to the catalyst case is positioned in the flow direction of the exhaust gas (that is, the axial direction of the catalyst case). Alternatively, the end surface of the catalyst is in contact with the buffer member.

When the end surface of the catalyst comes into contact with the downstream cone or the cushioning member in this way, part of the flow path of the exhaust gas in the catalyst is blocked. In addition, the catalyst is easily chipped due to vibration of the exhaust gas purifying device. Therefore, the purification performance of the catalyst is lowered. In addition, defects such as clogging of the catalyst and abnormal noise may occur due to the missing catalyst.

An object of one aspect of the present disclosure is to provide an exhaust gas purification device capable of suppressing deterioration in purification performance and damage of a catalyst.

According to one aspect of the present disclosure, a cylindrical catalyst case into which exhaust gas of an internal combustion engine is introduced, a catalyst stored in the catalyst case, and an outer surface of the catalyst and an inner peripheral surface of the catalyst case are brought into contact with each other. and a downstream cone connected to the downstream side of the catalyst case in the exhaust gas flow direction.

The upstream end of the downstream cone in the direction of exhaust gas flow is inserted into the catalyst case and either contacts the buffer member or faces the buffer member in the axial direction of the catalyst case with a gap therebetween. A gap is provided between the catalyst and the end of the downstream cone in the radial direction of the catalyst case.

According to such a configuration, since the end of the downstream cone restricts the downstream movement of the buffer member, it is possible to suppress the downstream shift of the catalyst held by the buffer member. In addition, since the catalyst is arranged apart from the downstream cone in both the axial direction and the radial direction of the catalyst case, deterioration in purification performance and breakage of the catalyst are suppressed.

In one aspect of the present disclosure, the end of the downstream cone may be curved toward the inside or the outside of the downstream cone. According to such a configuration, since the cushioning member contacts the curved portion of the end portion, breakage of the cushioning member can be suppressed.

In one aspect of the present disclosure, the ends of the downstream cone may be folded back so that the inner peripheral surfaces or the outer peripheral surfaces of the downstream cone overlap. According to such a configuration, it is possible to enhance the effect of suppressing breakage of the cushioning member.

FIG. 1 is a schematic front view of an exhaust gas purifier according to an embodiment. FIG. 2 is a schematic cross-sectional view along line II-II of FIG. 3A is a schematic partial enlarged view of the vicinity of the end of the downstream cone of FIG. 2, and FIG. 3B is a schematic partial enlarged view of the vicinity of the end of the downstream cone in an embodiment different from FIG. 3A. . 4A is a schematic partial enlarged view of the vicinity of the end of the downstream cone in an embodiment different from FIG. 3A, and FIG. 4B is a schematic view of the vicinity of the end of the downstream cone in an embodiment different from FIG. 3A. It is a partially enlarged view.

Embodiments to which the present disclosure is applied will be described below with reference to the drawings.
[1. First Embodiment]
[1-1. composition]
An exhaust gas purification device 1 shown in FIG. 1 is provided in an exhaust gas flow path of an internal combustion engine.

The exhaust gas purification device 1 purifies exhaust gas. Examples of internal combustion engines to which the exhaust gas purification device 1 is connected include gasoline engines and diesel engines used in automobiles.

The exhaust gas purification device 1 includes an upstream cone 2 , a catalytic converter 3 and a downstream cone 4 .

<Upstream cone>
The upstream cone 2 is a member into which the exhaust gas of the internal combustion engine is introduced. The upstream cone 2 is arranged on the most upstream side in the exhaust gas flow direction in the exhaust gas purifier 1 .

The upstream cone 2 is a truncated cone-shaped cylinder whose upper and lower surfaces are open and whose diameter increases from the upstream side to the downstream side. The upstream cone 2 has an inlet 21 that introduces the exhaust gas into the upstream cone 2 . The inlet 21 is provided at the upstream end of the upstream cone 2 . An exhaust manifold or the like connected to the internal combustion engine is connected to the inlet 21 .

<Catalytic converter>
Catalytic converter 3 is arranged downstream of upstream cone 2 . As shown in FIG. 2 , the catalytic converter 3 has a catalyst case 31 , a catalyst 32 and a buffer member 33 . 2, illustration of the upstream cone 2 is omitted.

(catalyst case)
The catalyst case 31 is a tubular member connected to the upstream cone 2 . The upstream end of the catalyst case 31 is fixed to the downstream opening of the upstream cone 2 by welding or the like. Exhaust gas G is introduced into the catalyst case 31 from the upstream cone 2 . A catalyst 32 and a buffer member 33 are housed in the catalyst case 31 .

(catalyst)
The catalyst 32 reforms or collects environmental pollutants in the exhaust gas G through contact with the exhaust gas G, thereby purifying the exhaust gas G.

The catalyst 32 is housed in the catalyst case 31 and forms a plurality of flow paths in the catalyst case 31 through which the exhaust gas G flows in the axial direction of the catalyst case 31 . That is, the catalyst 32 has a plurality of channels extending from the upstream cone 2 toward the downstream cone 4 and not communicating with each other or communicating with each other.

The catalyst 32 has, for example, a three-dimensional shape in which a plurality of tubes having polygonal (for example, square, hexagonal, etc.) cross sections perpendicular to the flow direction of the exhaust gas G are assembled. That is, the catalyst 32 has a three-dimensional shape (for example, a honeycomb shape) in which a plurality of partition plates extending in the axial direction of the catalyst case 31 are arranged in a grid.

A gasoline particulate filter (GPF), for example, is used as the catalyst 32 . GPF is based on cordierite ceramic. By using GPF, the particulate matter (PM) collection performance is enhanced, making it easier to comply with exhaust gas regulations, which have been increasing in recent years. On the other hand, since the GPF has low strength, measures against damage during assembly and use are required.

(buffer member)
The buffer member 33 is a cylindrical member that covers the entire outer surface of the catalyst 32 in the circumferential direction. The buffer member 33 holds the catalyst 32 by contacting the outer surface of the catalyst 32 and the inner peripheral surface of the catalyst case 31 . The downstream end of the buffer member 33 is located upstream of the downstream end of the catalyst 32 . That is, the catalyst 32 protrudes further downstream than the buffer member 33 .

The buffer member 33 is elastically deformable in the radial and axial directions of the catalyst case 31 . That is, the cushioning member 33 has lower rigidity and is softer than the catalyst case 31 and the catalyst 32 . The buffer member 33 is wound around the outer surface of the catalyst 32 and press-fitted into the catalyst case 31 .

The surface roughness of the outer surface of catalyst 32 is greater than the surface roughness of the inner peripheral surface of catalyst case 31 . Therefore, in the axial direction of the catalyst case 31 , the frictional force of the buffer member 33 with respect to the catalyst 32 is greater than the frictional force of the buffer member 33 with respect to the catalyst case 31 . Therefore, the cushioning member 33 slides against the catalyst case 31 while holding the catalyst 32 . As the cushioning member 33, for example, a material woven with aluminum fibers in a mat shape is used.

<Downstream cone>
The downstream cone 4 is a member connected to the downstream side of the catalyst case 31 of the catalytic converter 3 . The downstream cone 4 is a truncated cone-shaped cylinder whose upper and lower surfaces are open and whose diameter decreases from the upstream side to the downstream side.

The upstream opening of the downstream cone 4 is connected to the downstream end of the catalyst case 31 . An opening on the downstream side of the downstream cone 4 constitutes an outlet 41 through which the exhaust gas G is discharged from the exhaust gas purification device 1 .

An upstream end 42 of the downstream cone 4 constitutes an upstream opening of the downstream cone 4 and is inserted into the catalyst case 31 . As shown in FIG. 3A, the outer peripheral surface of the end portion 42 is in contact with the inner peripheral surface of the downstream end portion 31A of the catalyst case 31. As shown in FIG. The downstream cone 4 and the catalyst case 31 are welded together at a welding portion W including the edge of the downstream end portion 31A of the catalyst case 31 .

The end face of the end portion 42 of the downstream cone 4 is in contact with the end face of the buffer member 33 on the downstream side. That is, the end portion 42 abuts against the buffer member 33 from the downstream side. The end surface of the end portion 42 overlaps the catalyst 32 in the radial direction of the catalyst case 31 .

The end portion 42 of the downstream cone 4 is arranged between the catalyst 32 and the catalyst case 31 in the radial direction of the catalyst case 31 . A gap S<b>1 is provided between the catalyst 32 and the end portion 42 of the downstream cone 4 in the radial direction of the catalyst case 31 .

That is, the catalyst 32 faces the end portion 42 in the radial direction of the catalyst case 31 . Specifically, in the radial direction of the catalyst case 31 , the catalyst 32 is not in contact with the end portion 42 and no other member exists between the catalyst 32 and the end portion 42 .

As shown in FIG. 3B, the end portion 42 of the downstream cone 4 may face the buffer member 33 in the axial direction of the catalyst case 31 with a gap S2 interposed therebetween. That is, a gap S2 may be provided between the buffer member 33 and the end portion 42 in the axial direction of the catalyst case 31 . Such an air gap S2 may be formed due to variations in the dimensions and assembly positions of the components that constitute the exhaust gas purifying device 1 .

When the gap S<b>2 exists between the cushioning member 33 and the end portion 42 in this way, the cushioning member 33 contacts the end portion 42 by shifting the cushioning member 33 toward the downstream side. As a result, further downstream displacement of the cushioning member 33 is restricted.

As shown in FIG. 4A, the end 42 of the downstream cone 4 may curve toward the inside of the downstream cone 4 (that is, away from the catalyst case 31). In FIG. 4A , the end surface 421 of the end portion 42 faces the catalyst 32 with a gap in the radial direction of the catalyst case 31 , and part of the outer peripheral surface of the end portion 42 is in contact with the buffer member 33 . Other components such as the buffer member 33 and the reinforcing member may be arranged between the end surface 421 and the catalyst 32 .

Furthermore, as shown in FIG. 4B, the end portion 42 of the downstream cone 4 may be folded back in a U shape around a folded portion 42A so that the inner peripheral surfaces of the downstream cone 4 overlap each other. 4B, the folded portion 42A of the end portion 42 (that is, the bottom portion of the “U”) is in contact with the cushioning member 33. In FIG. Further, the folded portion 42A may face the cushioning member 33 with a gap therebetween.

The folded portion 42A faces the catalyst 32 with a gap therebetween in the radial direction of the catalyst case 31 . Other parts such as the cushioning member 33 and the reinforcing member may be arranged between the folded portion 42A and the catalyst 32. As shown in FIG.

In addition, in FIG. 4B, there may be a gap between the base portion 42B of the end portion 42 and the overlapping portion 42C. The base portion 42B is a portion that contacts the outer peripheral surface of the catalyst case 31 . The overlapping portion 42C is a portion ahead of the folded portion 42A, and is a portion overlapped with the base portion 42B from the radially inner side of the catalyst case 31. As shown in FIG.

<Manufacturing method>
The exhaust gas purification device 1 is obtained, for example, by the following manufacturing method. First, the buffer member 33 is wound around the peripheral surface of the catalyst 32 . Next, the catalyst 32 around which the buffer member 33 is wound is press-fitted into the catalyst case 31 . After that, the upstream cone 2 and the downstream cone 4 are welded to the catalyst case 31 .

According to this manufacturing method, by press-fitting the catalyst 32 around which the buffer member 33 is wound into the catalyst case 31, the holding force of the catalyst 32 by the buffer member 33 is lowered and the external force to the catalyst 32 is reduced. 32 is suppressed. Therefore, even when using a low-strength catalyst 32 such as GPF, for example, it can be manufactured with the same equipment and procedure as when using a high-strength catalyst 32 . In addition, the number of parts and the number of welding points can be made the same as in the conventional case.

<Action>
When the exhaust gas purification device 1 is used, the pressure of the exhaust gas flowing through the exhaust gas purification device 1 (that is, the air resistance of the catalyst 32) causes the catalyst 32 to move downstream.

In response to this, the cushioning member 33 holding the catalyst 32 also tries to move downstream together with the catalyst 32, but the cushioning member 33 comes into contact with the end 42 of the downstream cone 4, and the movement of the cushioning member 33 is restricted. be done. As a result, the movement of the catalyst 32 is also restricted by the frictional force between the catalyst 32 and the buffer member 33 .

[1-2. effect]
According to the embodiment detailed above, the following effects are obtained.
(1a) Since the end portion 42 of the downstream cone 4 restricts the downstream movement of the buffer member 33, downstream displacement of the catalyst 32 held by the buffer member 33 can be suppressed. In addition, since the catalyst 32 is arranged apart from the downstream cone 4 in both the axial direction and the radial direction of the catalyst case 31, deterioration in purification performance and breakage of the catalyst 32 are suppressed.

(1b) In the case where the end portion 42 of the downstream cone 4 contacts the cushioning member 33 shown in FIG. 3A, the effect of suppressing displacement of the catalyst 32 can be enhanced.

(1c) In the case where the end portion 42 of the downstream cone 4 is curved toward the inside of the downstream cone 4 shown in FIG. Since it becomes difficult to contact the edge portion, damage to the cushioning member 33 can be suppressed. In addition, while suppressing breakage of the buffer member 33 in this manner, the catalyst case 31 and the downstream cone 4 can be easily joined.

(1d) In the case shown in FIG. 4B in which the end portion 42 of the downstream cone 4 is folded back so that the inner peripheral surfaces of the downstream cone 4 overlap each other, the cushioning member 33 is pushed by the edge portion of the end surface 421 compared to the case shown in FIG. 4A. Since it becomes difficult to contact, the effect of suppressing breakage of the cushioning member 33 can be enhanced.

[2. Other embodiments]
Although the embodiments of the present disclosure have been described above, it is needless to say that the present disclosure is not limited to the above embodiments and can take various forms.

(2a) In the exhaust gas purifier 1 of the above embodiment, the end portion 42 of the downstream cone 4 in FIG. 4A may be curved toward the outside of the downstream cone 4 . That is, the end surface of the end portion 42 of the downstream cone 4 may face or be in contact with the inner peripheral surface of the catalyst case 31 .

Also, the end portion 42 of the downstream cone 4 in FIG. 4B may be folded back so that the outer peripheral surfaces of the downstream cone 4 overlap each other. That is, in FIG. 4B, the base portion 42B may be positioned outside the overlapping portion 42C. Also, the end portion 42 of the downstream cone 4 may not be completely folded back and may be curved in an arc shape.

(2b) In the exhaust gas purification device 1 of the above embodiment, the tip of the end portion 42 of the downstream cone 4 may be made of mesh. In this case, the mesh serves as the end portion 42 of the downstream cone 4 and faces the cushioning member 33 through contact or a gap.

(2c) The function of one component in the above embodiments may be distributed as multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiment may be omitted. Also, at least a part of the configuration of the above embodiment may be added, replaced, etc. with respect to the configuration of the other above embodiment. It should be noted that all aspects included in the technical idea specified by the wording in the claims are embodiments of the present disclosure.

DESCRIPTION OF SYMBOLS 1... Exhaust gas purification device, 2... Upstream cone, 3... Catalytic converter, 4... Downstream cone,
21... Inlet, 31... Catalyst case, 31A... Downstream end, 32... Catalyst, 33... Cushioning member,
41... discharge port, 42... end, 42A... folded portion, 42B... base portion,
42C... overlapping portion, 421... end surface.

Claims (3)

a tubular catalyst case into which the exhaust gas of the internal combustion engine is introduced;
a catalyst stored in the catalyst case;
a buffer member that holds the catalyst by contacting the outer surface of the catalyst and the inner peripheral surface of the catalyst case;
a downstream cone connected to the downstream side of the catalyst case in the flow direction of the exhaust gas;
with
The upstream end of the downstream cone in the direction of flow of the exhaust gas is inserted into the catalyst case and is in contact with the cushioning member, or separates the cushioning member from a gap in the axial direction of the catalyst case. facing through
An exhaust gas purification device, wherein a gap is provided between the catalyst and the end portion of the downstream cone in the radial direction of the catalyst case. The exhaust gas purifier according to claim 1,
The exhaust gas purification device, wherein the end portion of the downstream cone is curved toward the inside or the outside of the downstream cone. The exhaust gas purification device according to claim 2,
The exhaust gas purification device, wherein the end portion of the downstream cone is folded back so that the inner peripheral surfaces or the outer peripheral surfaces of the downstream cone overlap each other.

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