JP7160738B2 - EGR device - Google Patents

Description

The present disclosure relates to EGR devices.

2. Description of the Related Art An EGR (exhaust gas recirculation) device that purifies exhaust gas with a catalytic converter in an internal combustion engine of an automobile and circulates a part of the purified exhaust gas to the internal combustion engine is known (see Patent Document 1).

In the conventional EGR device, in order to simplify the structure, an EGR gas outlet is provided downstream of the catalytic converter, and a pipe for sending EGR gas to the internal combustion engine extends from downstream to upstream of the catalytic converter. . This pipe is arranged on the side of the catalytic converter.

JP-A-2004-176554

If the pipe for EGR gas is provided on the side of the catalytic converter as described above, the width of the EGR device inevitably increases. Therefore, the space required for mounting the EGR device increases.

One aspect of the present disclosure aims to provide an EGR device capable of reducing the space required for mounting.

One aspect of the present disclosure is a catalytic converter having an upstream portion having an internal space into which exhaust gas of an internal combustion engine is introduced, a cylindrical catalyst case connected to the upstream portion, and a catalyst stored in the catalyst case. , a downstream portion having an internal space connected to the downstream side of the catalytic converter in the exhaust gas flow direction, and an EGR pipe for circulating part of the exhaust gas to the internal combustion engine.

Further, the catalyst constitutes a channel through which the exhaust gas flows in the axial direction of the catalyst case. The upstream portion includes an inlet for introducing exhaust gas into the upstream portion, an EGR outlet to which an EGR pipe is connected, a first space communicating with the inlet, and a second space communicating with the EGR outlet. and a partition section that partitions the internal space of the section.

According to such a configuration, part of the exhaust gas that has passed through the catalyst from the upstream portion and reached the downstream portion flows in the reverse direction through the catalyst and is discharged from the EGR outlet in the upstream portion. Therefore, exhaust gas purified by the catalyst can be taken out as EGR gas from the upstream portion. As a result, there is no need to arrange the EGR piping on the side of the catalytic converter, so the space required for mounting the EGR device can be reduced.

In one aspect of the present disclosure, the upstream section may have a cylindrical upstream section main body provided with an inlet, and a plate-shaped mounting member provided with an EGR outlet. The attachment member may be attached to the upstream body so as to cover a portion of the upstream body from the outside. The partition portion may be configured by a portion of the upstream portion main body that is covered with the attachment member. According to such a configuration, since the partition can be formed by a part of the upstream section main body, the upstream section can be formed more easily than when the partition is provided as a separate member.

In one aspect of the present disclosure, the upstream main body may have a plurality of plate-like split pieces connected in the circumferential direction of the upstream main body. According to such a configuration, it is possible to easily form the upstream portion main body having a shape capable of configuring the second space by being covered with the mounting member by joining the plurality of split pieces.

In one aspect of the present disclosure, the upstream section may have a tubular upstream section body provided with an inlet and an EGR outlet. The partition section may be configured by a plate-like member arranged inside the upstream section main body. According to such a configuration, the first space and the second space can be formed using the conventionally shaped upstream body.

FIG. 1 is a schematic front view of the EGR device of the embodiment. 2 is a schematic side view of the EGR device of FIG. 1. FIG. FIG. 3 is a schematic cross-sectional view along line III-III in FIG. 4A is a schematic cross-sectional view along line IVA-IVA in FIG. 1, and FIG. 4B is a schematic cross-sectional view along line IVB-IVB in FIG. FIG. 5 is a schematic front view of an EGR device of an embodiment different from that of FIG. FIG. 6 is a schematic cross-sectional view taken along line VI-VI of FIG. FIG. 7 is a schematic cross-sectional view of an EGR device of an embodiment different from FIGS. 1 and 5. FIG.

Embodiments to which the present disclosure is applied will be described below with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
An EGR device 1 shown in FIGS. 1 and 2 is provided in an exhaust gas flow path of an internal combustion engine.

The EGR device 1 purifies exhaust gas and circulates part of the purified exhaust gas to the internal combustion engine. Examples of internal combustion engines provided with the EGR device 1 include gasoline engines and diesel engines used in automobiles.

The EGR device 1 includes an upstream portion 2 , a catalytic converter 3 , a downstream portion 4 and an EGR pipe 5 .

<Upstream part>
The upstream portion 2 is a member having an internal space into which the exhaust gas of the internal combustion engine is introduced. The upstream portion 2 is arranged on the most upstream side in the flow direction of the exhaust gas in the EGR device 1 .

The upstream portion 2 is a truncated cone-shaped cylindrical body (that is, a cone) whose upper and lower surfaces are open and whose diameter increases from the upstream side to the downstream side. The upstream section 2 has an inlet 21 , an EGR outlet 22 , an upstream section main body 23 and a mounting member 24 .

The introduction port 21 is an opening that introduces the exhaust gas into the upstream portion 2 and is provided at the upstream end portion of the upstream portion 2 . An exhaust manifold or the like connected to the internal combustion engine is connected to the inlet 21 .

The EGR outlet 22 is an opening to which an EGR pipe 5, which will be described later, is connected. The EGR outlet 22 is provided on the peripheral wall of the upstream portion 2 . EGR gas is discharged from the EGR outlet 22 . The opening area of the EGR outlet 22 is smaller than the opening area of the inlet 21 .

As shown in FIGS. 3 and 4A, the upstream section main body 23 is a cylindrical member provided with an inlet 21 . The upstream end portion of the upstream portion main body 23 forms the inlet 21, and the downstream end portion forms an opening communicating with a catalyst case 31 of the catalytic converter 3, which will be described later.

The upstream section main body 23 defines a first space S<b>1 communicating with the inlet 21 and the catalyst case 31 . Further, the upstream portion main body 23 has a truncated cone shape in which a portion to which a mounting member 24 described later is mounted is recessed inward.

The mounting member 24 is a plate-like member (that is, patch) provided with the EGR outlet 22 . The attachment member 24 is attached to the upstream body 23 so as to cover a portion of the upstream body 23 from the outside. Specifically, the mounting member 24 is fixed to these members by welding or the like so as to straddle the outer peripheral surface of the upstream portion main body 23 and the outer peripheral surface of the catalyst case 31 .

A second space S<b>2 communicating with the EGR outlet 22 and the catalyst case 31 is defined by the upstream portion main body 23 and the mounting member 24 . Specifically, the upstream section main body 23 has a partition section 23A that partitions the internal space of the upstream section 2 into a first space S1 and a second space S2.

The partition portion 23A is configured by a portion of the upstream portion main body 23 covered with the mounting member 24 . As shown in FIG. 3, the partition portion 23A partially enters the catalyst case 31 and extends to the vicinity of the upper end portion of the catalyst 32, which will be described later. That is, when viewed from the axial direction of the catalyst case 31, the partition portion 23A is arranged at a position overlapping the catalyst 32. As shown in FIG.

Inside the upstream portion 2, movement of the exhaust gas from the first space S1 to the second space S2 is prevented by the partition portion 23A. That is, the exhaust gas in the first space S1 flows through at least the catalytic converter 3 to the second space S2.

<Catalytic converter>
The catalytic converter 3 is arranged downstream of the upstream section 2 . The catalytic converter 3 has a catalyst case 31 , a catalyst 32 and mats 33 .

The catalyst case 31 is a tubular member connected to the upstream portion 2 . The upstream end of the catalyst case 31 is fixed to the downstream opening of the upstream section 2 by welding or the like. A catalyst 32 and a mat 33 are stored in the catalyst case 31 .

The catalyst 32 reforms or collects environmental pollutants in the exhaust gas through contact with the exhaust gas, thereby purifying the exhaust gas. 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 flows in the axial direction of the catalyst case 31 . That is, the catalyst 32 has a plurality of channels extending from the upstream portion 2 toward the downstream portion 4 and not 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 are gathered. 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.

The mat 33 is an elastically deformable member arranged between the catalyst case 31 and the catalyst 32, as shown in FIG. 4B. The mat 33 covers the outer peripheral surface of the catalyst 32 along the circumferential direction of the catalyst case 31 .

<Downstream>
As shown in FIG. 3 , the downstream portion 4 is a member having an internal space connected to the downstream side of the catalytic converter 3 . The downstream portion 4 is a truncated cone-shaped cylindrical body (that is, a cone) 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 portion 4 is fixed to the downstream end of the catalyst case 31 by welding or the like. A downstream opening of the downstream portion 4 forms an exhaust port 41 through which exhaust gas is discharged from the EGR device 1 .

<EGR piping>
The EGR pipe 5 circulates part of the exhaust gas to the internal combustion engine. One end of the EGR pipe 5 is connected to the EGR outlet 22 of the upstream portion 2 by welding or the like. The EGR pipe 5 is arranged apart from the catalytic converter 3 .

<Flow of Exhaust Gas>
As shown in FIG. 3 , the exhaust gas introduced into the first space S<b>1 of the upstream section 2 from the inlet 21 passes through the catalyst 32 in the axial direction of the catalyst case 31 and flows into the downstream section 4 .

Part of the exhaust gas that has passed through the catalytic converter 3 passes through the side portion 32A of the catalyst 32 that communicates with the second space S2 of the upstream portion 2 in the downstream portion 4 along the axial direction of the catalyst case 31, It flows into the second space S2.

That is, part of the exhaust gas in the downstream portion 4 reversely passes through the catalytic converter 3 again as EGR gas. This flow of EGR gas is generated when the EGR pipe 5 becomes negative pressure with respect to the catalytic converter 3 . The EGR gas that has flowed into the second space S2 is supplied from the EGR pipe 5 to the internal combustion engine.

Exhaust gas purified by the catalytic converter 3, excluding the EGR gas supplied to the second space S2, is discharged from the exhaust port 41 of the downstream portion 4 to the atmosphere through a pipe (not shown).

[1-2. effect]
According to the embodiment detailed above, the following effects are obtained.
(1a) Part of the exhaust gas that has passed through the catalyst 32 from the upstream portion 2 and reached the downstream portion 4 flows in the reverse direction through the catalyst 32 and is discharged from the EGR outlet 22 of the upstream portion 2 . Therefore, the exhaust gas purified by the catalyst 32 can be taken out from the upstream portion 2 as EGR gas. As a result, the EGR pipe 5 does not need to be arranged on the side of the catalytic converter 3, so the space required for mounting the EGR device 1 can be reduced.

(1b) Since the partition portion 23A that partitions the first space S1 and the second space S2 is formed by a part of the upstream portion main body 23, the upstream portion 2 can be easily separated compared to the case where the partition portion 23A is provided as a separate member. can be formed.

[2. Second Embodiment]
[2-1. Constitution]
The EGR device 11 shown in FIG. 5 includes an upstream portion 12 , a catalytic converter 3 , a downstream portion 4 and an EGR pipe 5 . The catalytic converter 3, the downstream portion 4, and the EGR pipe 5 are the same as those of the EGR device 1 of FIG.

<Upstream part>
The upstream portion 12 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 portion 12 has an inlet 21 , an EGR outlet 22 , an upstream portion main body 123 and a mounting member 24 . The inlet 21, the EGR outlet 22, and the mounting member 24 are the same as those of the upstream portion 2 in FIG.

The upstream section main body 123 is a cylindrical member provided with the introduction port 21 . The upstream section main body 123 has a first split piece 123A and a second split piece 123B. That is, the upstream main body 123 of this embodiment is obtained by dividing the upstream main body 23 of FIG. 1 into a plurality of split pieces 123A and 123B. Note that the upstream section main body 123 may be divided into three or more divided pieces.

As shown in FIG. 6, the first split piece 123A and the second split piece 123B are connected in the circumferential direction of the upstream portion main body 123 by, for example, welding. In this embodiment, the first space S1 is defined by the first split piece 123A and the second split piece 123B.

A part of the second split piece 123B covered with the mounting member 24 constitutes a partition part 123C. That is, the second space S2 is defined by the partition portion 123C, which is a part of the second split piece 123B, and the mounting member 24. As shown in FIG.

[2-2. effect]
According to the embodiment detailed above, the following effects are obtained.
(2a) The upstream main body 123 having a shape capable of forming the second space S2 by being covered with the mounting member 24 can be easily formed by joining the plurality of split pieces 123A and 123B.

[3. 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.

(3a) In the EGR device of the above embodiment, the partition does not necessarily have to be part of the upstream section main body. In other words, the partition may be a separate member from the upstream section main body. Also, the upstream portion and the downstream portion may be integral parts of the catalyst case of the catalytic converter. Further, the upstream and downstream portions are not limited to conical shapes.

For example, in the EGR device 1A shown in FIG. It has a partition part 25 . Thereby, the first space S1 and the second space S2 can be formed using the conventionally shaped upstream portion main body 23 . Further, in the EGR device 1A, the cylindrical upstream portion 2A and the cylindrical downstream portion 3 are integrated with the catalyst case 31 of the catalytic converter 3. As shown in FIG.

(3b) 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.

Reference Signs List 1, 11 EGR device, 2, 12 upstream section, 3 catalytic converter,
4... Downstream portion, 5... EGR pipe, 21... Inlet, 22... EGR outlet,
23...Upstream part main body, 23A...Partition part, 24...Mounting member, 25...Partition part,
31... catalyst case, 32... catalyst, 32A... side part, 33... mat, 41... outlet,
123...Upstream part main body, 123A...First split piece, 123B...Second split piece,
123C... Partition part.

Claims (2)

an upstream portion having an internal space into which the exhaust gas of the internal combustion engine is introduced;
a catalytic converter having a tubular catalyst case connected to the upstream portion and a catalyst housed in the catalyst case;
a downstream portion having an internal space connected to the downstream side of the catalytic converter in the flow direction of the exhaust gas;
an EGR pipe that circulates a portion of the exhaust gas to the internal combustion engine;
with
The catalyst constitutes a channel through which the exhaust gas flows in the axial direction of the catalyst case,
The upstream part is
an inlet for introducing the exhaust gas into the upstream section;
an EGR outlet to which the EGR pipe is connected;
a partition section that partitions the internal space of the upstream section into a first space that communicates with the inlet and a second space that communicates with the EGR extraction port;
a cylindrical upstream body provided with the introduction port;
a plate-shaped mounting member provided with the EGR outlet;
has
The attachment member is attached to the upstream body so as to cover a part of the upstream body from the outside,
The EGR device , wherein the partition portion is configured by a portion of the upstream portion main body that is covered with the mounting member . The EGR device according to claim 1 ,
The EGR device, wherein the upstream portion main body has a plurality of plate-like split pieces connected in a circumferential direction of the upstream portion main body.

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