JP7744285B2 - exhaust purification device - Google Patents

Description

This disclosure relates to an exhaust purification device.

As described in Patent Document 1, known techniques for catalytic converters include providing a heat insulator that covers the outer surface of the exhaust pipe that houses the catalyst, and providing a heat-resistant mat material between the outer surface of the exhaust pipe and the heat insulator. Also known is a technique for holding the heat insulator in place in such catalytic converters by applying surface pressure from the mat material to the heat insulator.

Japanese Patent Application Laid-Open No. 2019-74039

However, when the heat insulator is held by surface pressure from the mat material, there is a risk that the heat insulator may become displaced due to vibrations of the vehicle or the like.
An object of one aspect of the present disclosure is to suppress misalignment of a heat insulator.

One aspect of the present disclosure is an exhaust purification device configured to purify vehicle exhaust gases, comprising an exhaust pipe, a heat insulator, a buffer portion, and at least one protrusion. The exhaust pipe is configured to house a purification member that purifies exhaust gases. The heat insulator is arranged to surround the outer circumferential surface of the exhaust pipe. The buffer portion is provided between the heat insulator and the outer circumferential surface of the exhaust pipe. The protrusion portion is provided on the outer circumferential surface of the exhaust pipe. The buffer portion has at least one accommodation space that houses the protrusion portion.

With the above configuration, the protrusions on the exhaust pipe are housed in the accommodation space of the buffer section, preventing the buffer section from shifting in position relative to the exhaust pipe. This prevents the heat insulator located outside the buffer section from shifting in position.

In one embodiment of the present disclosure, the top of the protrusion may be formed with a top surface that spreads out like a plane.
According to the above configuration, when the protruding portion comes into contact with the buffer portion, damage to the buffer portion can be suppressed.

In one aspect of the present disclosure, the accommodation space may be a hole-like space in the buffer portion.
According to the above configuration, the accommodation space can be suitably formed.
In one aspect of the present disclosure, the heat insulator may have first and second groove portions that are groove-shaped portions, and the first and second groove portions may have first and second side edge portions, respectively. The first and second groove portions may be arranged to circumferentially surround the outer circumferential surface of the exhaust pipe by arranging the first and second side edge portions of the first groove portion to face the first or second groove portion of the second groove portion, respectively. The buffer portion may have first and second buffer portions, and the first and second buffer portions may be arranged in the first and second groove portions, respectively. The accommodation space may be formed by a gap between an end of the first buffer portion and an end of the second buffer portion.

According to the above configuration, the accommodation space can be provided more simply.
In one aspect of the present disclosure, the accommodating space may penetrate the buffer portion. The heat insulator may further include at least one connecting portion provided on the heat insulator, connected to the protrusion, and accommodated in the accommodating space. The protrusion may be accommodated in the accommodating space while connected to the connecting portion.

The above configuration more effectively prevents the insulator from shifting out of position.

1 is a side view of an exhaust gas purification device according to a first embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 2 is a perspective view of a protrusion according to the first embodiment. FIG. 10 is a perspective view of a protrusion of a modified example. FIG. 10 is a side view of a modified exhaust gas purification device. FIG. 6 is a cross-sectional view perpendicular to the axis of an exhaust purification device according to a second embodiment. 10 is an explanatory diagram of a protrusion in an exhaust gas purification device according to a third embodiment. FIG. 10 is an explanatory diagram of a protruding portion and a connecting portion in an exhaust gas purification device according to a fourth embodiment. FIG. 10 is an explanatory diagram of a protruding portion and a connecting portion in an exhaust gas purification device according to a fifth embodiment. FIG. 13 is an explanatory diagram of a protruding portion and a connecting portion in an exhaust gas purification device according to a modified example of the fifth embodiment. FIG.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that the embodiments of the present disclosure are in no way limited to the following embodiments, and various forms may be adopted as long as they fall within the technical scope of the present disclosure.

[First embodiment]
[1. Overview]
An exhaust gas purification device 1 of the first embodiment is provided in a flow path of exhaust gas from an internal combustion engine of a vehicle and is configured to purify the exhaust gas (see Figures 1 and 2). As an example, the exhaust gas purification device 1 is configured as a catalytic converter and is provided adjacent to the downstream side of the exhaust manifold of the internal combustion engine.

The exhaust gas purification device 1 includes a purification member 2, a converter section 3, and a heat insulating device.
The purification member 2 is a member for purifying exhaust gas, and may be configured as a catalyst that reforms or captures pollutants in the exhaust gas by coming into contact with the exhaust gas, for example.

The converter section 3 is configured as an exhaust pipe that forms a flow path for exhaust gas from the internal combustion engine, and houses the purification member 2 inside. The purification member 2 may be cylindrical, for example. The converter section 3 is configured as a cylindrical section that extends straight along the axis 10 of the purification member 2. For example, the axis 10 passes through or near the center of a cross section of the purification member 2 that is perpendicular to the axis 10. The shape of the exhaust pipe is not limited to this and can be determined as appropriate.

The heat shield device is configured to block heat radiation from the converter section 3 and includes a heat insulator 4 and a buffer section 5.
[2. Heat insulator]
The heat insulator 4 is a substantially cylindrical member that surrounds the converter unit 3 while leaving a gap with respect to the outer peripheral surface of the converter unit 3 (see FIGS. 1 and 2). The heat insulator 4 is made of, for example, stainless steel or aluminum, and suppresses heat radiation from the exhaust pipe. The heat insulator 4 is disposed to surround the converter unit 3, and a cross section perpendicular to the axis 10 (hereinafter simply referred to as a cross section) is, for example, circular.

The heat insulator 4 has first and second groove portions 40, 41, which are groove-shaped portions. The first and second groove portions 40, 41 each have, for example, an arc-shaped (for example, semicircular) cross section and first and second side edge portions 40A, 40B, 41A, 41B extending in the direction of the axis 10 (in other words, the flow direction of the exhaust gas). The first and second side edge portions 40A, 40B, 41A, 41B are located at both ends of the cross section of the first and second groove portions 40, 41.

The first and second side edge portions 40A, 40B, 41A, 41B of the first and second groove portions 40, 41 are each provided with, for example, two flange portions 42. The first and second groove portions 40, 41 are arranged so that the first side edge portions 40A, 41A face each other, and the second side edge portions 40B, 41B face each other, and the flange portions 42 provided on the facing edges are joined together. Note that the joining may be, for example, mechanical joining using bolts and nuts, joining by welding, or joining by adhesive. Furthermore, joining using a combination of these methods may also be used, for example.

[3. Buffer section]
The buffer section 5 is disposed between the inner peripheral surface of the heat insulator 4 and the outer peripheral surface of the converter section 3, and is provided so as to surround the converter section 3 (see FIGS. 1 and 2). The buffer section 5 includes first and second mat materials 50 and 51. The first and second mat materials 50 and 51 are disposed so as to cover the inner peripheral surfaces of the first and second groove portions 40 and 41 of the heat insulator 4, respectively, and the cross sections of the first and second mat materials 50 and 51 are arc-shaped.

In addition, as an example, the first and second mat materials 50, 51 are adhered to the outer peripheral surface of the converter section 3 or the inner peripheral surface of the heat insulator 4 with an adhesive. Of course, this is not limited to this, and the first and second mat materials 50, 51 may be fixed to the converter section 3 or the heat insulator 4 by means other than an adhesive, or the first and second mat materials 50, 51 may not be fixed to the converter section 3 or the heat insulator 4.

The first and second mat materials 50, 51 are configured as buffer materials and, as an example, contain a material with a lower thermal conductivity than air (e.g., glass wool or rock wool), which provides a heat-shielding function. Of course, the first and second mat materials 50, 51 are not limited to these materials and can be configured from a variety of materials.

Here, the portions located at both ends of the cross section of the first and second mat materials 50, 51 are referred to as the first and second end portions 50A, 50B, 51A, 51B, respectively. The first and second mat materials 50, 51 are arranged so that the first end portions 50A, 51A face each other and the second end portions 50B, 51B face each other. Furthermore, gaps are formed between the first end portions 50A, 51A and between the second end portions 50B, 51B.

The first and second mat materials 50, 51 are sandwiched between the heat insulator 4 and the converter section 3 in a compressed state. As a result, surface pressure from the compressed first and second mat materials 50, 51 is applied to the inner circumferential surface of the heat insulator 4, thereby holding the heat insulator 4 to the converter section 3.

[4. Protrusions and Storage Spaces]
In the first embodiment, two protrusions 30 are provided protruding from the outer peripheral surface of the converter unit 3 (see FIGS. 1 and 2 ). The two protrusions 30 are arranged at the same position in the direction of the axis 10, and are provided at positions facing each other across the axis 10. In other words, the protrusions 30 are arranged at intervals of approximately 180° in the circumferential direction centered on the axis 10. Furthermore, each protrusion 30 is provided near the upstream end of the converter unit 3 in the flow direction of exhaust gas.

Furthermore, each protrusion 30 is formed integrally with the converter section 3. Specifically, for example, if the converter section 3 is manufactured by casting, each protrusion 30 may be cast as part of the converter section 3. Furthermore, for example, if the converter section 3 is manufactured by press molding, each protrusion 30 may be formed as part of the converter section 3 during press molding.

Furthermore, the first and second mat materials 50, 51 each have a storage space 52, which is a hole-like space that penetrates the mat material. These two storage spaces 52 may also be formed as hole-like spaces that do not penetrate the mat materials 50, 51, but have openings adjacent to the outer peripheral surface of the converter section 3. The two storage spaces 52 are also provided in positions facing each other across the axis 10, similar to the protrusion section 30. Furthermore, as an example, each storage space 52 is provided approximately in the center of the cross section of the respective mat material.

Each protrusion 30 is accommodated in one of the accommodation spaces 52. The protrusion 30 accommodated in the accommodation space 52 comes into contact with or is in close proximity to the portion of the mat material that faces the accommodation space 52 (hereinafter referred to as the wall surface). In other words, the accommodation space 52 is larger than or equal to the protrusion 30.

Specifically, as an example, each protrusion 30 has a truncated cone shape, and a flat, expanding top surface 31 is formed at the top of each protrusion 30 (see Figure 3). Alternatively, each protrusion 30 may have a truncated cone shape, for example, with a polygonal cross section perpendicular to the protrusion direction, or may have a quadrangular truncated cone shape with a quadrangular top surface 31, as shown in Figure 4. Furthermore, without being limited to this, a curved top surface may also be formed at the top of each protrusion 30.

Furthermore, if the protrusion 30 has a quadrangular pyramid shape, the protrusion 30 may be arranged so that the side of the quadrangular cross section perpendicular to the protruding direction intersects with the direction in which the heat insulator 4 is predicted to shift. Specifically, for example, if the cross section of the protrusion 30 is rectangular and the heat insulator 4 is predicted to shift in the circumferential direction around the axis 10, the protrusion 30 may be arranged so that the long side of the cross section is perpendicular to the circumferential direction, as shown in Figure 5.

The shape of each protrusion 30 may be, for example, cylindrical or prismatic. The number of protrusions 30 and storage spaces 52 may be one or three or more. The positions of the protrusions 30 and storage spaces 52 in the direction of the axis 10 and in the circumferential direction around the axis 10 can be determined as appropriate.

Second Embodiment
5. Overview
The exhaust gas purification device 1 of the second embodiment has a configuration similar to that of the first embodiment, but differs from that of the first embodiment in the configuration of the accommodation space 52 for the first and second mat materials 50, 51. The following describes the exhaust gas purification device 1 of the second embodiment, focusing on the differences from the first embodiment.

In the second embodiment, the first and second mat materials 50, 51 do not have hole-shaped storage spaces. Instead, two storage spaces 52 are formed by the gaps between the ends of each mat material (see Figure 6). Specifically, the storage space 52 is formed by the gap between the first end 50A of the first mat material 50 and the first end 51A of the second mat material 51. The storage space 52 is also formed by the gap between the second end 50B of the first mat material 50 and the second end 51B of the second mat material 51. In the second embodiment, the two storage spaces 52 are also positioned opposite each other across the axis 10, as in the first embodiment.

Each protrusion 30 is accommodated in one of the accommodation spaces 52. Furthermore, the protrusion 30 accommodated in each accommodation space 52 is in contact with or close to the wall surface formed by the ends of the first and second mat materials 50, 51.

[Third embodiment]
6. Overview
The exhaust gas purification device 1 of the third embodiment has a configuration similar to that of the first embodiment, but differs from the first embodiment in the configuration of the protrusion 30 of the converter section 3 and the configuration of the accommodation space 52 for the first and second mat materials 50, 51. The exhaust gas purification device 1 of the third embodiment will be described below, focusing on the differences from the first embodiment.

In the third embodiment, each protrusion 30 is formed by joining another member (e.g., wire mesh) to the converter unit 3 (see Figure 7). Furthermore, each storage space 52 is formed as a hole-like space that does not penetrate the mat material and has an opening facing the outer peripheral surface of the converter unit 3.

The top surface 31 of the protrusion 30 accommodated in each storage space 52 abuts against the portion of the mat material that forms the bottom of the storage space 52. However, this is not limited to this, and a gap may be formed between the top surface 31 of the protrusion 30 and the mat material. Also, a gap is formed between the side surface of the protrusion 30 and the portion of the mat material adjacent to the storage space 52. However, this is not limited to this, and the side surface of the protrusion 30 may abut against the mat material.

[Fourth embodiment]
7. Overview
The exhaust gas purification device 1 of the fourth embodiment has a configuration similar to that of the first embodiment, but differs from the first embodiment in the configuration of the protrusion 30 of the converter section 3 and in that two connecting portions 43 are provided on the heat insulator 4. The exhaust gas purification device 1 of the fourth embodiment will be described below, focusing on the differences from the first embodiment.

In the fourth embodiment, each protrusion 30 is formed by welding another member (e.g., wire mesh) to the converter unit 3 (see Figure 8). A protrusion is provided in the center of the top surface of each protrusion 30, and this top surface forms a convex portion 32.

Similarly to the first embodiment, each of the storage spaces 52 is formed as a hole-like space that penetrates the mat material.
Each of the first and second grooves 40, 41 of the heat insulator 4 is provided with a connecting portion 43 that protrudes from the inner peripheral surface of the groove. Each connecting portion 43 is made of, for example, a wire mesh and is welded to the inner peripheral surface of the corresponding groove. Similar to the protrusions 30, these connecting portions 43 are positioned opposite each other across the axis 10 and are accommodated in the accommodation space 52 from the outer peripheral surface side of the mat material. Each connecting portion 43 has a hole in the center of its top surface, forming a recess 44. The recess 44 of the connecting portion 43 is capable of fitting with the protrusion 32 of the protrusion 30.

In other words, the protrusions 30 and the coupling portions 43 are coupled together by fitting the convex portions 32 of the protrusions 30 into the concave portions 44 of the coupling portions 43. Each protrusion 30 is then housed in the housing space 52 while coupled to the coupling portions 43.

Note that each protrusion 30 and each connecting portion 43 may be made of a material other than wire mesh, and may be joined to the converter section 3 or heat insulator 4 by a method other than welding.

In addition, a gap is formed between the side of each protrusion 30 and each connecting portion 43 and the portion of the mat material adjacent to the storage space 52. However, this is not limited to this, and these side surfaces may also abut against the mat material.

Fifth Embodiment
8. Overview
The exhaust gas purification device 1 of the fifth embodiment has a configuration similar to that of the fourth embodiment, but differs from that of the fourth embodiment in the configuration of the protrusion 30 of the converter unit 3 and the configuration of the joining portion 43 of the heat insulator 4. The exhaust gas purification device 1 of the fifth embodiment will be described below, focusing on the differences from the fourth embodiment.

In the fifth embodiment, each protrusion 30 is cylindrical and includes a rivet 33 and a wire mesh 34 (see Figure 9). The rivet 33 has a head 33A, which is a disk-shaped portion having first and second surfaces, and a body 33B that protrudes from the center of the first surface of the head 33A. Instead of the rivet 33, for example, a weld bolt may be used. The first surface of the head 33A is welded to the outer peripheral surface of the converter unit 3. Furthermore, a wire mesh 34 is provided so as to cover the second surface of the head 33A and the side surface of the body 33B, thereby forming a cylindrical protrusion 30. As an example, the wire mesh 34 may be welded to the head 33A.

In addition, each coupling portion 43 is, for example, cylindrical, and is formed by recessing the groove toward the converter portion 3 (in other words, inward). The center of the top surface of each coupling portion 43 is recessed so as to protrude outward, thereby forming a recess 44 on the top surface.

When the protrusion 30 is press-fit into the recess 44 of the connecting portion 43, the wire mesh 34 of the protrusion 30 deforms, and the wire mesh 34 and the body 33B of the rivet 33 are inserted into the recess 44. This joins the protrusion 30 and connecting portion 43. Each protrusion 30 is then housed in the housing space 52 while connected to the connecting portion 43.

Alternatively, each protrusion 30 may be constructed by welding a cylindrical wire mesh 34 to the outer peripheral surface of the converter section 3 (Figure 10). Similarly, the wire mesh 34 (in other words, the protrusion 30) may be press-fitted into the recess 44 of the connecting section 43, and the wire mesh 34 may be deformed to connect the protrusion 30 and connecting section 43.

In addition, for example, each protrusion 30 may be composed of only rivets 33, or may be composed of a material other than rivets 33 or wire mesh 34. Furthermore, each protrusion 30 may be joined to the converter section 3 by a method other than welding. Furthermore, each joining section 43 may be formed by joining another material to a groove in the heat insulator 4.

In addition, a gap is formed between the side of each protrusion 30 and each connecting portion 43 and the portion of the mat material adjacent to the storage space 52. However, this is not limited to this, and these side surfaces may also abut against the mat material.

[9. Effects]
(1) In the first to fifth embodiments, the protrusions 30 provided on the converter unit 3 are accommodated in the accommodation spaces 52 provided in the buffer unit 5, thereby preventing the buffer unit 5 from shifting in position relative to the converter unit 3. This prevents the heat insulator 4 located outside the buffer unit 5 from shifting in position.

(2) Each protrusion 30 has a top surface 31. Therefore, when the protrusion 30 comes into contact with the mat material, damage to the mat material can be suppressed.
(3) In the first and second embodiments, each protrusion 30 is formed integrally with the converter unit 3. This makes it easier to form each protrusion 30, and simplifies the manufacturing process of the exhaust gas purification device 1.

(4) Furthermore, in the third to fifth embodiments, each protrusion 30 is formed by joining another member, such as a wire mesh or a rivet, to the outer peripheral surface of the converter section 3. This allows protrusions 30 to be formed in a variety of shapes and materials, thereby improving the functionality of the protrusions 30. Furthermore, when forming the protrusions 30 integrally with the converter section 3, a dedicated mold may be required. However, when forming the protrusions 30 by joining another member to the outer peripheral surface of the converter section 3, a dedicated mold is not required, and the protrusions 30 can be formed using more general-purpose equipment.

(5) In the first and third to fifth embodiments, the storage space 52 is a hole-shaped space provided in the mat material. Therefore, the storage space 52 can be formed in a suitable manner.
(6) In the fourth and fifth embodiments, each protrusion 30 is housed in the housing space 52 while being coupled to the coupling portion 43 provided on the heat insulator 4. This makes it possible to more effectively prevent the heat insulator 4 from shifting in position.

(7) In the second embodiment, the storage space 52 is formed by the gap between the end of the first mat material 50 and the end of the second mat material 51. This makes it easier to provide the storage space 52.

10. Other Embodiments
(1) In the exhaust gas purification device 1 of the first to fifth embodiments, the buffer section 5 includes first and second mat materials 50, 51. However, the buffer section 5 may be configured, for example, by one mat material provided so as to surround the outer peripheral surface of the converter section 3, or may be configured by three or more mat materials arranged side by side so as to surround the outer peripheral surface of the converter section 3. Note that when the buffer section 5 is configured by three or more mat materials, an accommodation space 52 may be provided in each mat material, and the protrusion may be accommodated in each accommodation space 52.

(2) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[11. Correspondence of Wording]
The first and second mat members 50 and 51 correspond to examples of first and second buffer portions, respectively.

1...exhaust gas purification device, 10...axis, 2...purification member, 3...converter section, 30...projection section, 31...top surface, 4...heat insulator, 40, 41...first and second groove sections, 40A, 41A...first side edge section, 40B, 41B...second side edge section, 43...joint section, 5...buffer section, 50, 51...first and second mat members, 50A, 51A...first end section, 50B, 51B...second end section, 52...accommodation space.

Claims (7)

An exhaust purification device configured to purify exhaust gas from a vehicle,
an exhaust pipe configured to accommodate a purification member that purifies exhaust gas;
a heat insulator disposed around an outer circumferential surface of the exhaust pipe;
a buffer portion provided between the heat insulator and an outer peripheral surface of the exhaust pipe;
at least one protrusion provided on an outer peripheral surface of the exhaust pipe,
The buffer portion has at least one accommodation space that accommodates the protrusion. The exhaust gas purification device according to claim 1,
The protrusion has a top surface that spreads out like a plane at its top. The exhaust gas purification device according to claim 1 or 2,
The accommodation space is a hole-shaped space in the buffer portion. The exhaust gas purification device according to claim 1 or 2,
the heat insulator has first and second groove portions which are groove-shaped portions, the first and second groove portions having first and second side edge portions, respectively;
the first and second side edge portions of the first groove portion are disposed to face the first or second edge portion of the second groove portion, respectively, so that the first and second groove portions are disposed to go around the outer circumferential surface of the exhaust pipe;
the buffer portion includes first and second buffer portions, the first and second buffer portions being disposed in the first and second groove portions, respectively;
The exhaust gas purification device, wherein the accommodation space is formed by a gap between an end of the first buffer portion and an end of the second buffer portion. The exhaust gas purification device according to claim 1 or 2,
The accommodation space passes through the buffer portion,
the heat insulator further includes at least one coupling portion that is coupled to the protrusion and is accommodated in the accommodation space;
The protrusion is housed in the housing space while being connected to the connecting portion. The exhaust gas purification device according to claim 1 or 2,
The accommodation space is a space that penetrates the buffer portion,
The protrusion does not come into contact with the heat insulator.
Exhaust purification device. The exhaust gas purification device according to claim 1 or 2,
The accommodation space is a space that does not penetrate the buffer portion,
A part of the buffer portion is disposed between the protrusion portion accommodated in the accommodation space and the heat insulator.
Exhaust purification device.