WO2022085387A1

WO2022085387A1 - Exhaust heat recovery device

Info

Publication number: WO2022085387A1
Application number: PCT/JP2021/036038
Authority: WO
Inventors: 智幸内田; こずえ鈴木; 恭平小池
Original assignee: 株式会社ユタカ技研
Priority date: 2020-10-23
Filing date: 2021-09-30
Publication date: 2022-04-28
Also published as: JP2022068969A

Abstract

A communication hole 21 is positioned upstream of a heat exchanger 14. A first flow path 30 has a branch path 31 that branches a flow of exhaust gas with the positioning of the communication hole 21. Upstream of the branch path 31, a narrow path 35 in which a flow path area narrows toward the branch path 31 is positioned. An area B2 of an opening 105 opened and closed by a valve 100 is larger than a minimum flow path area B1 in the narrow path 35. Behind the valve 100, a flow path area B3 at an arbitrary position in a third flow path 80 is equal to or larger than the area B2 of the opening 105 opened and closed by the valve 100 (B1 < B2 ≦ B3).

Description

Waste heat recovery device

The present invention relates to an exhaust heat recovery device that exchanges heat by the heat of exhaust gas.

There is known an exhaust heat recovery device that heats the cooling water by the heat of the exhaust gas generated by the engine while the vehicle is running. As an exhaust heat recovery device, for example, there is a technique disclosed in Patent Document 1. FIG. 10 is a reprint of FIG. 1 of Patent Document 1 and reassigned.

The exhaust heat recovery device 500 has an inner cylinder 510 whose inside is a first flow path 501 for exhaust gas, an outer cylinder 520 surrounding the inner cylinder 510, and an annular heat exchange provided on the outer periphery of the outer cylinder 520. The vessel 530, the upstream closing member 540 arranged on the upstream side of the heat exchanger 530, the downstream closing member 550 arranged on the downstream side of the heat exchanger 530, and the downstream end of the downstream closing member 550. It has a valve 560 that can open and close the valve 560, and a discharge cylinder 570 that discharges the exhaust gas that has passed through the first flow path 501 or the exhaust gas that has been heat-exchanged via the heat exchanger 530 to the outside.

A second flow path 502 for exhaust gas is configured on the outer circumference of the outer cylinder 520. The second flow path 502 is a region surrounded by the upstream closing member 540, the heat exchanger 530, and the downstream closing member 550. The outer cylinder 520 is formed with a plurality of communication holes 520a that allow the first flow path 501 and the second flow path 502 to communicate with each other.

The exhaust heat recovery device 500 can be switched between a heat recovery mode that recovers the heat of the exhaust gas and a non-recovery mode that does not recover the heat of the exhaust gas. Switching between the heat recovery mode and the non-recovery mode is performed by opening and closing the valve 560.

When the valve 560 is closed, the exhaust gas introduced from the upstream end of the inner cylinder 510 which is the exhaust gas introduction port passes through the first flow path 501 and the communication hole 520a, and is the first. It flows into the flow path 502 of 2. The exhaust gas flowing into the second flow path 502 exchanges heat with the cooling water flowing inside the heat exchanger 530, passes through the inside of the discharge cylinder 570, and is discharged to the outside (heat recovery mode).

In the heat recovery mode, when the cooling water reaches a predetermined temperature, the thermoactuator (not shown) is driven to open the valve 560. The exhaust gas passes through the first flow path 501 and the inside of the discharge cylinder 570 and is discharged to the outside (non-recovery mode).

Japanese Patent No. 4810511

The communication hole 520a is always open. Therefore, even when the valve 560 is open (non-recovery mode), a part of the exhaust gas flowing through the first flow path 501 flows into the second flow path 502 through the communication hole 520a.

As described above, the exhaust gas flowing into the second flow path 502 heats the cooling water via the heat exchanger 530. That is, even in the non-recovery mode for which heat exchange is not intended, the exhaust gas flows into the second flow path 502, so that heat exchange is inevitably generated and the cooling water is heated.

The waste heat recovery device 500 of the prior art has a configuration for suppressing heat exchange in this non-recovery mode. Specifically, a space S is secured between the outer peripheral surface of the outer cylinder 520 and the inner peripheral surface of the heat exchanger 530. This space S is a part of the second flow path 502, and constitutes a flow path in which the exhaust gas that has entered from the communication hole 520a is directed to the upstream closing member 540.

The exhaust gas is folded back by the upstream closing member 540, passes through the inside of the heat exchanger 530, and flows into the inside of the discharge cylinder 570. The second flow path 502 including such a folding back has a large pressure loss and makes it difficult for exhaust gas to flow. Heat exchange can be suppressed.

On the other hand, since it is necessary to secure a space S in order to make the flow path including the folding back, the waste heat recovery device 500 becomes large in the radial direction.

An object of the present invention is to provide an exhaust heat recovery device capable of miniaturization while suppressing heat exchange between exhaust gas and cooling water in a non-recovery mode.

According to the first aspect of the invention, a first cylinder having a cylindrical shape and the inside of which is a first flow path of exhaust gas,
A second cylinder which has a cylindrical shape and which constitutes a second flow path together with the first cylinder by surrounding the first cylinder,
A closing member that closes the upstream end of the second cylinder with reference to the flow direction of the exhaust gas, and
A communication hole formed in the first cylinder and communicating the first flow path and the second flow path,
A heat exchanger that exchanges heat between the exhaust gas that has flowed into the second flow path from the communication hole and the cooling water.
A valve that can open and close the first flow path on the downstream side of the communication hole,
In an exhaust heat recovery device having a tubular shape and a third cylinder whose inside is a third flow path of exhaust gas that has passed through the first flow path or the second flow path.
The communication hole is located on the upstream side of the heat exchanger.
The exhaust gas flowing through the second flow path flows toward the third flow path without going toward the closing member side,
The first flow path has a branch path for branching the flow of exhaust gas due to the location of the communication hole.
Immediately upstream of the branch road, a reduced road having a smaller flow path area toward the branch road is located.
The area of the opening opened and closed by the valve is larger than the minimum flow path area in the reduced path.
Behind the valve, the flow path area at any position in the third flow path is equal to or greater than the area of the opening opened and closed by the valve. A featured exhaust heat recovery device is provided.

As described in claim 2, the first cylinder is composed of a single member.

As described in claim 3, the cross section of the portion of the first cylinder in which the communication hole is located has a race track shape as a whole.

As described in claim 4, the first cylinder is composed of two members, a first half body on the upstream side and a second half body on the downstream side, each of which has a tubular shape. The reduction path is configured inside the first half body, and the second half body has the communication hole.

As described in claim 5, the reduced path is joined to the inner peripheral surface of the first cylinder and a part of the inner peripheral surface of the first cylinder to guide the flow of the exhaust gas. It is composed of a guide plate and a guide plate.

As described in claim 6, the cross section of the closing member has a wavy shape.

The waste heat recovery device according to claim 1 has a communication hole for communicating the first flow path and the second flow path provided on the outer periphery of the first flow path. The first flow path has a branch path for branching the flow of exhaust gas due to the location of the communication hole. Immediately upstream of the branch road, there is a reduced road where the flow path area becomes smaller toward the branch road.

Furthermore, the area of the opening opened and closed by the valve is larger than the minimum flow path area in the reduced path. Behind the valve, the area of the flow path at any position in the third flow path is equal to or greater than the area of the opening opened and closed by the valve.

From the above configuration, in the so-called non-recovery mode, it is difficult for the exhaust gas to flow into the second flow path through the communication hole, and the flow of the exhaust gas from the second flow path to the third flow path can also be suppressed. .. As a result, the heat recovery of the exhaust gas by the heat exchanger provided in the second flow path can be suppressed.

In addition, the communication hole is located upstream of the heat exchanger. The exhaust gas flowing through the second flow path flows toward the third flow path, not toward the closing member side. Therefore, the waste heat recovery device can be miniaturized in the radial direction.

From the above, it is possible to provide an exhaust heat recovery device capable of miniaturization while suppressing heat exchange between the exhaust gas and the cooling water in the non-recovery mode.

In claim 2, the first cylinder is composed of a single member. By plastically deforming a part of the straight pipe (for example, diameter reduction processing or diameter expansion processing), the first flow path can be configured with the minimum number of parts.

In claim 3, the cross section of the portion of the first cylinder where the communication hole is located has a race track shape as a whole. Therefore, the first flow path can be formed by performing plastic working such that the straight pipe is sandwiched in the radial direction and crushed.

In claim 4, the first cylinder is composed of two members, a first half body on the upstream side and a second half body on the downstream side, each of which has a tubular shape. A reduction path is configured inside the first half body. The second half has a communication hole. Therefore, neither the first half body nor the second half body can be complicatedly processed to form the first cylinder.

In claim 5, the reduced path is composed of an inner peripheral surface of the first cylinder and a guide plate joined to a part of the inner peripheral surface of the first cylinder to guide the flow of exhaust gas. ing. Therefore, the reduced path can be constructed without performing plastic working for forming the reduced path.

In claim 6, the cross section of the closing member has a wavy shape. Therefore, even when the first cylinder is thermally expanded due to the heat of the exhaust gas, the closing member can absorb the thermal expansion of the first cylinder.

It is a perspective view of the exhaust heat recovery device by Example 1. FIG. FIG. 2 is a sectional view taken along line 2-2 of FIG. It is a perspective view of the 1st cylinder which constitutes the exhaust heat recovery apparatus of Example 1 and the 3rd cylinder. It is a cross-sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6A is a pressure distribution diagram inside the exhaust heat recovery device according to a comparative example. FIG. 6B is a pressure distribution diagram (cross-sectional view taken along the line 6B-6B of FIG. 1) inside the exhaust heat recovery device according to the first embodiment. It is sectional drawing of the exhaust heat recovery device by Example 2. FIG. FIG. 8A is a perspective view of the waste heat recovery device according to the third embodiment. FIG. 8B is a sectional view taken along line 8B-8B of FIG. 8A. FIG. 8C is a sectional view taken along line 8C-8C of FIG. 8A. FIG. 9A is a perspective view of the waste heat recovery device according to the fourth embodiment. 9B is a cross-sectional view taken along the line 9B-9B of FIG. 9A. It is a figure explaining the exhaust heat recovery device by the prior art.

An example will be described below based on the attached figure.

<Example 1>
FIG. 1 shows, for example, an exhaust heat recovery device 10 mounted on a four-wheeled vehicle. The exhaust heat recovery device 10 heats the cooling water by the heat of the exhaust gas generated by the engine.

In the figure, Us indicates upstream and Ds indicates downstream. The "upstream" and "downstream" are based on the flow direction of the exhaust gas flowing along the center line CL of the first cylinder. Further, the "upper end" refers to the upstream end in the exhaust gas flow direction, and the "lower end" refers to the downstream end in the exhaust gas flow direction.

Refer to FIGS. 1 and 2. The waste heat recovery device 10 has a first cylinder 20 having a cylindrical shape (for example, a cylindrical shape, but the cross section may be polygonal, the same applies hereinafter). The inside of the first cylinder 20 is a first flow path 30 for exhaust gas. The upper end portion 20a of the first cylinder 20 is an exhaust gas introduction port.

The first cylinder 20 is surrounded by a tubular second cylinder 40. The annular region between the inner peripheral surface of the second cylinder 40 and the outer peripheral surface of the first cylinder 20 constitutes the second flow path 50 of the exhaust gas. The first cylinder 20 is formed with two

communication holes

21, 21 that allow the first flow path 30 and the second flow path 50 to communicate with each other. The communication holes 21, 21 are displaced from each other by 180 degrees in the circumferential direction. The number and size of the communication holes 21 can be changed as appropriate.

In the second flow path 50, a tubular heat exchanger 14 that is in contact with the outer peripheral surface of the first cylinder 20 is arranged. The outer peripheral surface of the heat exchanger 14 is in contact with the inner peripheral surface of the second cylinder 40. Further, a sealing member (not shown) may be provided between the outer peripheral surface of the first cylinder 20 and the inner peripheral surface of the heat exchanger 14.

The upstream side of the second flow path 50 is closed by the annular closing member 60. The inner peripheral edge 61 of the closing member 60 is joined to the outer peripheral surface of the first cylinder 20. The outer peripheral edge 62 of the closing member 60 is joined to the outer peripheral surface of the upper end portion 40a of the second cylinder 40.

The portion (the portion extending in the radial direction) between the edge 61 on the inner peripheral side and the edge 62 on the outer peripheral side is referred to as the main body portion 63. The cross section of the main body 63 is wavy. Specifically, the main body portion 63 is located on the radial inner side and is located on the radial outer side of the first curved portion 64 and the first curved portion 64 which are curved so as to bulge toward the downstream side. It has a second curved portion 65, which is curved so as to bulge toward the upstream side.

A third cylinder 70 having a tubular shape is arranged on the downstream side of the second cylinder 40. The inside of the third cylinder 70 is a third flow path 80 for exhaust gas (see also FIG. 4). Exhaust gas that has passed through the first flow path 30 or the second flow path 50 flows through the third flow path 80.

The upper end portion 70a of the third cylinder 70 is joined to the outer peripheral surface of the lower end portion 40b of the second cylinder 40. The lower end 70b of the third cylinder 70 serves as an exhaust gas discharge port. Of the third cylinder 70, the portion between the upper end portion 70a and the lower end portion 70b is referred to as the main body portion 71.

The second cylinder 40 is surrounded by a fourth cylinder 90 having a tubular shape. The fourth cylinder 90 is composed of a first half body 91 surrounding a half of the outer circumference of the second cylinder 40 and a second half body 92 surrounding the other half.

The upper end portion 91a and the lower end portion 91b of the first half body 91 are joined to the outer peripheral surface of the second cylinder 40, respectively. The upper end portion 92a and the lower end portion 92b of the second half body 92 are joined to the outer peripheral surface of the second cylinder 40, respectively.

The annular region between the second cylinder 40 and the fourth cylinder 90 constitutes a cooling flow path 93 through which cooling water flows. An introduction pipe 15 capable of introducing cooling water into the cooling flow path 93 is connected to the first half body 91. A discharge pipe 16 capable of discharging cooling water from the cooling flow path 93 is connected to the second half body 92.

Refer to FIGS. 3 and 5. A part of the main body 71 of the third cylinder 70 holds the lower end 20b of the first cylinder 20. Looking at the main body 71 of the third cylinder 70 along the center line CL (see FIG. 5), the main body 71 is in contact with a part of the outer peripheral surface of the lower end 20b of the first cylinder 20. It has a pair of

arcuate contact portions

72,72. The pair of

contact portions

72, 72 are joined to the lower end portion 20b of the first cylinder 20. The portions of the main body 71 other than the pair of

contact portions

72, 72 are radially outwardly separated from the outer peripheral surface of the lower end portion 20b of the first cylinder 20. This portion is referred to as a pair of

separation portions

73,73.

Refer to FIGS. 2 and 5. The first flow path 30 can be opened and closed by a butterfly type valve. The valve has a rod-shaped rotary shaft 101, a disc-shaped valve body 102 fixed to the rotary shaft 101, and

columnar support members

103 and 103 that support both ends of the rotary shaft 101. ing.

The

support members

103 and 103 are inserted into and supported by the support holes 72a and 72a (see FIG. 3) formed in the pair of

contact portions

72 and 72 of the third cylinder 70.

Refer to FIG. The first flow path 30 has a branch path 31 for branching the flow of exhaust gas, an upper flow path 32 adjacent to the upstream side of the branch path 31, and a lower flow path 33 adjacent to the downstream side of the branch path 31. And, divide into.

Communication holes 21, 21 are located in the branch road 31. The flow path area A1 of the branch path 31 is constant.

The upper flow path 32 is adjacent to the first steady path 34, which is located on the most upstream side and has a constant flow path area A2, and the downstream side of the first steady path 34, and has a flow path area toward the downstream side. It has a smaller reduction path 35 and. The reduced road 35 is located immediately upstream of the branch road 31.

The lower flow path 33 is adjacent to the downstream side of the branch road 31, and is adjacent to the first expansion path 36 in which the flow path area increases toward the downstream side and the downstream side of the first expansion path 36. A second steady path 37 having a constant cage area A3 and a second expansion path 38 adjacent to the downstream side of the second steady path 37 and having a larger flow path area toward the downstream side. It has a third steady path 39 which is adjacent to the downstream side of the second expansion path 38 and has a constant flow path area A4.

Refer to FIGS. 3 and 4. The first cylinder 20 is composed of a single member. Specifically, the first cylinder 20 constitutes a first straight pipe portion 23 constituting the first steady path 34, a reduced section 24 constituting the reduced path 35, and a branch path 31. It has a branch portion 25 and a branch portion 25.

Further, the first cylinder 20 has a first expansion portion 26 constituting the first expansion path 36, a second straight pipe portion 27 constituting the second steady path 37, and a second. It has a second expansion portion 28 constituting the expansion path 38 of the above, and a third straight pipe portion 29 constituting the third steady path 39.

The branch portion 25 is a portion of the first cylinder 20 that has been reduced in diameter by diameter reduction processing. The third straight pipe portion 29 is a portion of the first cylinder 20 processed by diameter expansion processing. The outer shape of the reduced portion 24 is tapered, but it may be stepped. As long as the shape is such that the first flow path 30 can be formed, the portion to be reduced in diameter or expanded in diameter may be appropriately selected.

The third flow path 80 is divided into an upper flow path 81 on the upstream side of the valve opening and a lower flow path 82 on the downstream side.

The upper flow path 81 is two regions surrounded by the second enlarged portion 28, the third straight pipe portion 29, and the separated portion 73. The lower flow path 82 has a steady path 83 having a constant flow path area, and a reduced path 84 adjacent to the downstream side of the steady path 83 and having a smaller flow path area toward the downstream side.

The area B2 of the opening 105 (see also FIG. 5) opened and closed by the valve 100 is larger than the minimum flow path area B1 in the reduced path 35 (B2> B1). The minimum channel area B1 in the reduced path 35 and the channel area A1 of the branch path 31 are equal (B1 = A1). The flow path area A3 and the area B2 of the opening 105 are substantially equal (A3≈B2).

The flow path area at an arbitrary position (position within the range of the line R) in the lower flow path 82 is defined as the flow path area B3. The flow path area B3 is larger than the area B2 of the opening 105 (B3> B2). The flow path area B3 and the area B2 of the opening 105 may be set equally (B3 = B2).

In the first embodiment, the flow path area B3 is set so that the flow path area becomes smaller toward the downstream side. The flow path area B31 on the most downstream side is larger than the area B2 of the opening 105. For example, the flow path area B31 on the most downstream side may be set to be equal to the area B2 of the opening 105.

The operation of the waste heat recovery device 10 will be described.

Refer to FIG. When the valve 100 is closed, the exhaust gas introduced from the introduction port of the exhaust heat recovery device 10 (the upper end portion 20a of the first cylinder 20) reaches the upper flow path 32, the branch path 31, and the communication holes 21, 21. And flows into the second flow path 50. The exhaust gas that has flowed into the second flow path 50 enters the through hole 14c of the heat recovery body 14 and heats the heat recovery body 14. The heat of the heat recovery body 14 is transmitted to the cooling water flowing through the cooling flow path 93 via the second cylinder 40, and the cooling water is heated (heat recovery mode).

It can be said that the heat exchanger of the present invention is composed of the heat recovery body 14, the second cylinder 40, and the fourth cylinder 90. The heat exchanger may have other well-known configurations. The exhaust gas that has passed through the heat recovery body 14 passes through the third flow path 80 and is discharged from the discharge port (lower end 70b of the third cylinder 70). When the cooling water reaches a predetermined temperature, the thermoactuator (not shown) is driven to open the valve 100.

Refer to FIG. When the valve 100 is open, the exhaust gas flows through the first flow path 30, passes through the opening 105 of the valve 100, further flows through the third flow path 80, and is discharged from the discharge port (non-valve). Recovery mode).

The effect of the invention of Example 1 will be described.

FIG. 6A is a pressure distribution diagram of the exhaust heat recovery device 600 of the comparative example. The pressure distribution map is drawn in three stages of low pressure P1, medium pressure P2, and high pressure P3.

The first cylinder 601 is a straight pipe. The flow path area C1 of the first cylinder 601 is constant. The area C2 of the opening opened and closed by the valve 602 is smaller than the flow path area C1 of the first cylinder 601 (C2 <C1). The flow path area C3 at the lower end (discharge port) of the third cylinder 603 is equal to the flow path area C1 of the first cylinder 601 (C3 = C1).

In the exhaust heat recovery device 600 having such a configuration, the pressure of the first flow path 611 is high pressure P3. The pressure of the second flow path 612 became medium pressure P2. Therefore, as shown by the arrow (1), the exhaust gas easily flows from the first flow path 611 into the second flow path 612 through the communication hole.

Furthermore, the pressure on the upstream side of the third flow path 613 was medium pressure P2. On the other hand, the area around the lower end (discharge port) of the third cylinder 603 became a low pressure P1. Therefore, as shown by the arrow (2), the exhaust gas tends to flow from the upstream side of the third flow path 613 to the vicinity of the lower end portion (exhaust port). Therefore, even when the valve 602 is open, the exhaust gas easily passes through the second flow path 612, and heat recovery is performed.

Refer to FIG. In the first embodiment, the first flow path 30 includes a branch path 31 in which communication holes 21 and 21 are located to branch the flow of exhaust gas, and a reduced path 35 in which the flow path area becomes smaller toward the downstream side. ,have. The reduced road 35 is located immediately upstream of the branch road 31.

The area B2 of the opening 105 opened and closed by the valve 100 is larger than the minimum flow path area B1 in the reduced path 35 (B2> B1).

The flow path area at an arbitrary position (position within the range of the line R) in the lower flow path 82 is defined as the flow path area B3. The flow path area B3 is larger than the area B2 of the opening 105 (B3> B2).

Refer to FIG. 6B. In the exhaust heat recovery device 10 having the above configuration, there is no place where the high pressure P3 is reached. Of the first flow path 30, the pressure of the upper flow path 32 became the medium pressure P2, and the pressure of the lower flow path 33 also became the medium pressure. The pressure of the branch path 31 became low pressure P1. The pressure of the second flow path 50 became low pressure P1.

Since there is no pressure difference between the branch path 31 and the second flow path 50, it is possible to suppress the flow of exhaust gas from the branch path 31 to the second flow path 50 as shown by the arrow (3). can. Further, both the second flow path 50 and the third flow path 80 became low pressure P1. Since there is no pressure difference, it is possible to suppress the flow from the upper flow path 32 of the third flow path 80 to the vicinity of the discharge port as shown by the arrow (4).

From the above, heat exchange can be suppressed in the non-recovery mode in which the valve 100 is open.

Refer to FIG. In addition, the communication holes 21, 21 are located on the upstream side of the upper end surface 14a of the heat recovery body 14. The second flow path 50 is only a flow from the closing member 60 side to the third flow path 80. Since there is no flow from the third flow path 80 toward the closing member 60 side, the exhaust heat recovery device 10 can be miniaturized in the radial direction.

In addition, the cross section of the main body 63 of the closing member 60 is wavy. Therefore, even when the first cylinder 20 is thermally expanded due to the heat of the exhaust gas, the closing member 60 can absorb the thermal expansion of the first cylinder.

The effects of the above invention are also exhibited in Examples 2 to 4 described below. In Examples 2 to 4, the configuration of the first cylinder 20 is different from that of Example 1. The configurations common to those of the first embodiment are designated by the same reference numerals as those of the first embodiment, and the description thereof will be omitted.

<Example 2>
See FIG. 7. In the waste heat recovery device 200 of the second embodiment, the first cylinder 201 has a tubular shape, that is, a first half body 210 on the upstream side and a second half body 220 on the downstream side. It is composed of members. The first cylinder 201 may be composed of three or more members. Inside the first half body 210, a second reduced path 234 (reduced path), which will be described later, is configured. The second half body 220 has communication holes 21, 21.

The first flow path is divided into an upstream side flow path 230 inside the first half body 210 and a downstream side flow path 240 inside the second half body 220.

The upstream side flow path 230 has a first steady path 231 located on the most upstream side and having a constant flow path area, and a flow path area smaller toward the downstream side adjacent to the downstream side of the first steady path 231. The first reduced path 232, the second steady path 233 which is adjacent to the downstream side of the first reduced path 232 and has a constant flow path area, and the second steady path 233 which is adjacent to the downstream side of the second steady path 233. A second reduced path 234 (reduced path) in which the channel area becomes smaller toward the downstream side, and a third steady path 235 adjacent to the downstream side of the second reduced path 234 and having a constant channel area. ,have.

The first half body 210 includes a first straight pipe portion 211 constituting the first steady path 231, a first reduced section 212 constituting the first reduced path 232, and a second. The second straight pipe portion 213 constituting the steady path 233, the second reduced section 214 constituting the second reduced path 234, and the third constituting the third steady path 235. The straight pipe portion 215 and the straight pipe portion 215 are integrally configured.

The downstream flow path 240 includes a branch path 241 in which the communication holes 21, 21 are located, a fourth steady path 242 adjacent to the downstream side of the branch path 241 and having a constant flow path area, and a fourth steady path. The first expansion path 243, which is adjacent to the downstream side of the steady path 242 and the flow path area increases toward the downstream side, and the first expansion path 243, which is adjacent to the downstream side of the first expansion path 243, have a flow path area. It has a constant fifth steady path 244 and.

Specifically, the second half body 220 has a joint portion 221 joined to the outer peripheral surface of the second straight pipe portion 213, a branch portion 222 constituting the branch path 241 and a fourth. The fourth straight pipe portion 223 constituting the steady path 242, the first expanding section 224 constituting the first expansion path 243, and the fifth expanding section 244 constituting the fifth steady path 244. The straight pipe portion 225 and the straight pipe portion 225 are integrally configured.

A part of the third straight pipe portion 215 has entered the branch road 241. The lower end portion 215a of the third straight pipe portion 215 is located on the downstream side of the upstream edge 21b of the communication hole 21. The outer peripheral surface of the joint portion 221 is joined to the closing member 60.

In the second embodiment, the first cylinder 201 has two bodies, a first half body 210 constituting the second reduction path 234 and a second half body 220 having communication holes 21, 21. It is composed of members. That is, since the second reduction path 234 and the communication holes 21 and 21 are provided separately, the shapes of the

respective half bodies

210 and 220 are not complicated.

<Example 3>
FIG. 8A shows a first cylinder 310 constituting the waste heat recovery device of the third embodiment. Other configurations are the same as in Example 1. The first cylinder 310 is composed of a single member. The first cylinder 310 has a branch portion 312 in which communication holes 311 and 311 are located and the flow of exhaust gas is branched.

When viewed from the direction along the center line CL of the first cylinder 310 (see FIG. 8B), the cross section of the branch portion 312 has a race track shape as a whole. Specifically, the branch portion 312 is configured by integrally forming a pair of

straight lines

314, 314 extending in parallel with each other and a pair of

arcuate arc portions

313, 313. The communication holes 311 and 311 are formed in the

arc portions

313 and 313, respectively.

Refer to FIG. 8C. The configuration of the first flow path 320 inside the first cylinder 310 is the same as the basic configuration of the first flow path 30 (see FIG. 4) of the first embodiment. That is, the first flow path 320 has a first steady path 321, a reduced path 322, a branch path 323, a first expansion path 324, a second steady path 325, a second expansion path 326, and a third steady path. It can be divided into roads 327 and.

The cross section of the branch portion 312 of the first cylinder 310 has a race track shape. Therefore, the branch portion 312 can be formed by plastically working so as to sandwich the cylindrical straight pipe in the radial direction and crush it. Compared with the diameter reduction processing in which the diameter of the cylindrical straight pipe is reduced over the entire circumference, the first flow path 320 can be configured by simple processing.

<Example 4>
See FIGS. 9A and 9B. FIG. 9A shows a first cylinder 410 constituting the waste heat recovery device of the fourth embodiment. Other configurations are the same as in Example 1. In the first cylinder 410, which is composed of a single member, a guide plate 430 for guiding the exhaust gas flowing through the first flow path 420 is arranged inside the first cylinder 410.

The guide plate 430 is joined to the inner peripheral surface 410a of the first cylinder 410. The guide plate 430 is inclined to the downstream side from the joint with the inner peripheral surface 410a as a starting point.

Refer to FIG. 9C. The area surrounded by the guide surface 431 of the guide plate 430 and the inner peripheral surface 410a constitutes the reduced path 422. From the upstream side, the first flow path 420 includes the first steady path 421, the reduced path 422, the branch path 423, the second steady path 424, the expansion path 425, and the third steady path 426. Divide into ,. The flow path areas of the first steady path 421, the branch path 423, and the second steady path 424 are equal to each other.

The guide plate 430 and the communication hole 411 are at the same position in the circumferential direction, but may be arranged at different positions in the circumferential direction.

The area surrounded by the guide surface 431 of the guide plate 430 and the inner peripheral surface 410a constitutes the reduced path 422. The outer shape of the portion of the first cylinder 410 on the upstream side of the expansion path 425 is constant. Unlike the first to third embodiments, the reduced path 422 can be configured without plastic working to form the reduced path 422.

The present invention is not limited to Examples 1 to 4 as long as the actions and effects of the present invention are exhibited.

10 ... Exhaust heat recovery device 14 ... Heat recovery body (heat exchanger)
20 ... First cylinder 30 ... First flow path 31 ... Branch path 35 ... Reduction path 40 ... Second cylinder 50 ... Second flow path 60 ... Closing member 70 ... Third cylinder 100 ... Valve 105 ... Opening B1 ... Minimum flow path area in the reduced path B2 ... Area of the opening opened and closed by the valve B3 ... Flow path area 200 at any position in the third flow path behind the valve ... Exhaust heat recovery device 201 ... 1st cylinder 210 ... 1st half body 220 ... 2nd half body 310 ... 1st cylinder 311 ... Communication hole 312 ... Cross section of branch portion (cross section of a portion where the communication hole is located)
320 ... 1st flow path 410 ... 1st cylinder 410a ... Inner peripheral surface 411 of the 1st cylinder ... Communication hole 430 ... Guide plate

Claims

The first cylinder, which has a tubular shape and the inside is the first flow path for exhaust gas,
A second cylinder which has a cylindrical shape and which constitutes a second flow path together with the first cylinder by surrounding the first cylinder,
A closing member that closes the upstream end of the second cylinder with reference to the flow direction of the exhaust gas, and
A communication hole formed in the first cylinder and communicating the first flow path and the second flow path,
A heat exchanger that exchanges heat between the exhaust gas that has flowed into the second flow path from the communication hole and the cooling water.
A valve that can open and close the first flow path on the downstream side of the communication hole,
In an exhaust heat recovery device having a tubular shape and a third cylinder whose inside is a third flow path of exhaust gas that has passed through the first flow path or the second flow path.
The communication hole is located on the upstream side of the heat exchanger.
The exhaust gas flowing through the second flow path flows toward the third flow path without going toward the closing member side,
The first flow path has a branch path for branching the flow of exhaust gas due to the location of the communication hole.
Immediately upstream of the branch road, a reduced road having a smaller flow path area toward the branch road is located.
The area of the opening opened and closed by the valve is larger than the minimum flow path area in the reduced path.
Behind the valve, the flow path area at any position in the third flow path is equal to or greater than the area of the opening opened and closed by the valve. A featured exhaust heat recovery device.
The waste heat recovery device according to claim 1, wherein the first cylinder is composed of a single member.
The waste heat recovery device according to claim 2, wherein the cross section of the portion of the first cylinder in which the communication hole is located has a race track shape as a whole.
The first cylinder is composed of two members, a first half body on the upstream side and a second half body on the downstream side, each of which has a cylindrical shape.
The reduced path is configured inside the first half body.
The waste heat recovery device according to claim 1, wherein the second half body has the communication hole.
The reduced path is composed of an inner peripheral surface of the first cylinder and a guide plate joined to a part of the inner peripheral surface of the first cylinder to guide the flow of the exhaust gas. The exhaust heat recovery device according to claim 1, wherein the exhaust heat recovery device is provided.
The waste heat recovery device according to any one of claims 1 to 5, wherein the cross section of the closing member has a wavy shape.