JP2021173205A - Exhaust heat recovery device - Google Patents

Abstract

To propose an exhaust heat recovery device that satisfies requirements required for both a case of performing early warming-up and the like and a case of cooling exhaust gas to return it to an exhaust gas recirculation device.SOLUTION: An exhaust heat recovery device has a main flow channel 3 and an auxiliary flow channel 7 that communicates with the main flow channel 3 via a first communication hole 4 and a second communication hole 5, in which a first valve element 9 is rotatably provided for opening and closing the main flow channel 3. A portion on the first communication hole 4 side of the auxiliary flow channel 7 is partitioned by a partition member 10 to form a first flow passage 11 and a second flow passage 12. One end of the first flow passage 11 communicates with the main flow channel 3 through the first communication hole 4, and one end of the second flow passage 12 communicates with an exhaust gas recirculation device. The other ends of the first flow passage 11 and the second flow passage 12 communicate with one end of a third flow passage 15, and the other end of the third flow passage 15 communicates with the main flow channel 3 through the second communication hole 5. A first heat exchanger 17 is provided in the first flow passage 11, and a second heat exchanger 18 is provided in the second flow passage 12.SELECTED DRAWING: Figure 2

Description

The present invention relates to an exhaust heat recovery device.

The exhaust pipe through which the exhaust gas discharged from the internal combustion engine of an automobile flows has an exhaust heat recovery device used for early warm-up, etc., and an EGR cooler that cools the exhaust gas returned to the exhaust gas recirculation device (EGR). It is equipped.

The exhaust heat recovery device and the EGR cooler are both devices for exchanging heat between the exhaust gas and the cooling medium. Moreover, since the operation modes used by each are different, it is possible to share both.

As an example, a main flow path through which exhaust gas flows is provided, a sub-flow path that communicates with the main flow path, the first communication hole, and the second communication hole is provided, and the first communication hole and the second communication hole in the sub-flow path are provided. A heat exchanger is provided between the main flow path and the valve body so that the valve body can be opened and closed between the first communication hole and the second communication hole in the main flow path, and one of the main flow path and the second communication hole is blocked by the valve body. An exhaust heat recovery device is known in which the downstream side of the heat exchanger in the sub-channel and the exhaust gas recirculation device are communicated with each other.

In this exhaust heat recovery device, by closing the valve body, the main flow path is closed and the second communication hole is opened, and the exhaust gas passing through the heat exchanger of the sub flow path returns to the main flow path and heat is generated. Early warm-up and the like can be performed by the exchanger.

Further, by opening the valve body, the main flow path is opened, the second communication hole is closed, and the exhaust gas passing through the heat exchanger of the sub flow path is cooled and then sent to the exhaust gas recirculation device. It is supplied (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-446666

However, when the exhaust heat recovery device is used for early warm-up or the like, the back pressure is required to be lower than the heat recovery efficiency. On the other hand, when the exhaust heat recovery device cools the exhaust gas to return it to the exhaust gas recirculation device, it is required to have heat recovery efficiency rather than low back pressure.

In the exhaust heat recovery device described in Patent Document 1, since the heat exchanger is common between the case of performing early warm-up and the like and the case of cooling the exhaust gas to return it to the exhaust gas recirculation device, both of the above It may not be possible to meet the requirements of.

Therefore, an object of the present invention is to provide an exhaust heat recovery device that satisfies the requirements for both the case of performing early warm-up and the like and the case of cooling the exhaust gas to return it to the exhaust gas recirculation device. It is something to do.

In order to solve the above problems, it has a main flow path through which the exhaust gas discharged from the internal combustion engine flows, and a sub-flow path that communicates with the main flow path through the first communication hole and the second communication hole.
When a rotation shaft is provided between the first communication hole and the second communication hole, and a first valve body that opens and closes the main flow path is rotatably provided around the rotation shaft and the main flow path is opened. The second communication hole is closed by the first valve body, and the second communication hole is opened when the main flow path is closed by the first valve body.
The side portion of the first communication hole of the sub-flow path is partitioned by a partition member to form the first flow path and the second flow path, and one end of the first flow path is connected to the main flow path through the first communication hole. One end of the second flow path communicates with the exhaust gas recirculation device, and the other end of the first flow path and the other end of the second flow path are one end of the third flow path. The other end of the third flow path communicates with the main flow path through the second communication hole.
A first heat exchanger for exchanging heat between the exhaust gas and the medium is provided in the first flow path.
A second heat exchanger for exchanging heat between the exhaust gas and the medium is provided in the second flow path.

A third communication hole that communicates the first flow path and the second flow path is formed at the end of the partition member on the side of the first communication hole, and the third communication hole is opened and closed by the second valve body. West,
When the first valve body is closed, the second valve body may be opened so that the first flow path and the second flow path communicate with each other.

The first heat exchanger and the second heat exchanger are integrally formed.
At least the first communication hole side portion of the flow path through which the exhaust gas flows in the integrally formed heat exchanger is partitioned by the partition member, and the flow path through which the exhaust gas flows in the first heat exchanger and the said. A flow path through which the exhaust gas in the second heat exchanger flows may be formed.

The first heat exchanger and the second heat exchanger may be composed of separate members.

According to the present invention, a main flow path and a sub flow path are provided, and the side portion of the first communication hole of the sub flow path is partitioned by a partition member to form a first flow path and a second flow path, and the first flow path and the second flow path are formed in the first flow path. Provided a first heat exchanger for heat exchange between the exhaust gas and the medium, and a second heat exchanger for heat exchange between the exhaust gas and the medium in the second flow path to re-exhaust gas. When supplying exhaust gas to the circulation device, it passes through the first heat exchanger and the second heat exchanger, and when performing early warm-up, etc., at least after passing through the first heat exchanger, the main flow path. By returning to, the back pressure can be reduced when performing early warm-up, etc., and the exhaust gas is returned to the exhaust gas recirculation device, so that the heat exchange efficiency is achieved when cooling. Can be enhanced.

The perspective view of the exhaust heat recovery device which concerns on Example 1 of this invention. FIG. 1 is a vertical cross-sectional view of FIG. 1 in a state where the main flow path is open. FIG. 1 is a vertical cross-sectional view of FIG. 1 in a state where the main flow path is blocked. FIG. 1 is a vertical cross-sectional view of FIG. 1 in a state where a heat exchanger is not used. The vertical sectional view which shows another example of the exhaust heat recovery device which concerns on Example 1 of this invention. FIG. 5 is a diagram showing a state in which the main flow path is open in the exhaust heat recovery device according to the second embodiment of the present invention. FIG. 6 is a diagram showing a state in which the main flow path is blocked from the state shown in FIG. The figure of the state in which the heat exchanger is not used in the exhaust heat recovery device which concerns on Example 2 of this invention. FIG. 5 is a diagram showing a state in which the main flow path is open in the exhaust heat recovery device according to the third embodiment of the present invention. FIG. 9 is a diagram showing a state in which the main flow path is blocked from the state shown in FIG. The figure of the state in which the heat exchanger is not used in the exhaust heat recovery device which concerns on Example 3 of this invention. FIG. 5 is a diagram showing a state in which the main flow path is open in an example of the exhaust heat recovery device according to the fourth embodiment of the present invention. The figure of the state which blocked the main flow path from the state of FIG. FIG. 5 is a diagram showing a state in which a heat exchanger is not used in an example of the exhaust heat recovery device according to the fourth embodiment of the present invention.

The best embodiment of the present invention will be described with reference to the examples shown in the figure.

[Example 1]
FIG. 1 shows a perspective view of the exhaust heat recovery device 1 of the first embodiment of the present invention.

The exhaust heat recovery device 1 is arranged and used in an exhaust pipe through which exhaust gas discharged from an internal combustion engine of a vehicle such as an automobile or the like flows.

As shown in FIGS. 2 to 4, the exhaust heat recovery device 1 has a case 2, a main flow path 3 is formed in the case 2, and an upstream exhaust gas (not shown) is provided at an inflow port 3a provided on the upstream side. A downstream exhaust pipe (not shown) is connected to the downstream exhaust port 3b.

A first communication hole 4 and a second communication hole 5 provided on the downstream side of the first communication hole 4 are formed in the main flow path 3, and the first communication hole 4 and the second communication hole 5 are the main flow paths, respectively. A sub-channel 7 communicating with 3 is formed.

A rotation shaft 8 is arranged between the first communication hole 4 and the second communication hole 5 in the main flow path 3, and the first valve body 9 is rotatably provided around the rotation shaft 8.

As shown in FIG. 2, when the first valve body 9 is rotated in the downstream direction (counterclockwise direction in FIG. 2) about the rotation shaft 8 and opened so as to open the main flow path 3, the second communication is performed. The hole 5 is closed, and as shown in FIG. 3, the first valve body 9 is rotated in the upstream direction (clockwise in FIG. 3) about the rotation shaft 8 and closed so as to close the main flow path 3. Then, the second communication hole 5 is opened.

The side portion of the first communication hole 4 of the sub-flow path 7 is partitioned by a partition member 10, and the first flow path 11 and the second flow path 12 are partitioned in parallel. One end 11a of the first flow path 11 communicates only with the main flow path 3 through the first communication hole 4. Only the outlet 13 is formed at one end 12a of the second flow path 12, and does not communicate with other than the outlet 13. The outlet 13 communicates with the exhaust gas recirculation device (EGR) through a pipe (not shown).

The other end 11b of the first flow path 11 and the other end 12b of the second flow path 12 merge and communicate with one end 15a of the third flow path 15. The other end 15b of the third flow path 15 communicates only with the main flow path 3 through the second communication hole 5.

A first heat exchanger 17 is provided between the first communication hole 4 and the other end 11b in the first flow path 11, and is between the outlet 13 and the other end 12b in the second flow path 12. Is provided with a second heat exchanger 18.

In the first flow path 11, as shown in FIGS. 2 to 5, a space 19 is formed between the first communication hole 4 and the first heat exchanger 17.

Further, in the second flow path 12, as shown in FIGS. 2 to 5, a space 20 is formed between the outlet 13 and the second heat exchanger 18.

Space 19 and space 20 are separated by a partition member 10 and do not communicate with each other.

The first heat exchanger 17 has a plurality of medium flow paths 17a through which a medium such as cooling water of a cooling system of an internal combustion engine or the like flows, and a plurality of fluid flow paths 17b through which exhaust gas flows. The second heat exchanger 18 has a plurality of medium flow paths 18a through which a medium such as cooling water of a cooling system of an internal combustion engine or the like flows, and a plurality of fluid flow paths 18b through which exhaust gas flows.

The fluid flow path 17b of the first heat exchanger 17 and the fluid flow path 18b of the second heat exchanger 18 communicate with each other and are integrally formed. The medium flowing in from the medium inlet 20a passes through the medium flow paths 17a and 18a and then is discharged from the medium outlet 20b.

The medium flow path 17a of the first heat exchanger 17 and the medium flow path 18a of the second heat exchanger 18 are integrally formed, and the entire flow direction of the exhaust gas inside thereof is partitioned by the partition member 10, so that the medium flow is formed. The road 17a and the medium flow path 18a are partitioned. In this embodiment, the fluid flow path 17b of the first heat exchanger 17 and the flow path volume of the fluid flow path 18b of the second heat exchanger 18 are partitioned by the partition member 10 so as to be substantially the same. The ratio can be arbitrarily set. For example, as shown in FIG. 5, the flow path volume of the fluid flow path 17b of the first heat exchanger 17 is set to the flow path of the fluid flow path 18b of the second heat exchanger 18. It may be larger than the volume.

As described above, the first heat exchanger 17 and the second heat exchanger 18 are integrally formed.

With the above configuration, heat exchange is possible between the medium and the exhaust gas in the heat exchangers 17 and 18.

As shown in FIG. 2, the first valve body 9 is rotated in the downstream direction about the rotation shaft 8 to open the main flow path 3, the second communication hole 5 is closed, and the exhaust gas is regenerated. When a valve (not shown) in the circulation device is open, the exhaust gas flows through the main flow path 3 and also flows through the first communication hole 4 to the sub-flow path 7.

The exhaust gas that has passed through the first communication hole 4 enters the first flow path 11 and passes through the first heat exchanger 17, and then turns back because the second communication hole 5 is blocked, and the second flow path 12 After moving inward and passing through the second heat exchanger 18, it flows into the exhaust gas recirculation device through the outlet 13.

At this time, the exhaust gas passes through the first heat exchanger 17 and the second heat exchanger 18, is cooled, and then is supplied to the exhaust gas recirculation device, so that high heat exchange efficiency can be obtained. can.

Further, as shown in FIG. 3, the first valve body 9 is rotated about the rotation shaft 8 in the upstream direction from the state of FIG. 2, the main flow path 3 is closed, and the second communication hole 5 is opened. In addition, when a valve (not shown) in the exhaust gas recirculation device is closed, the exhaust gas flows from the main flow path 3 through the first communication hole 4 and into the sub-flow path 7.

The exhaust gas that has passed through the first communication hole 4 enters the first flow path 11 and passes through the first heat exchanger 17, and then the second flow path is closed because a valve (not shown) in the exhaust gas recirculation device is closed. It does not move into the 12 and passes through the third flow path 15. After that, the exhaust gas returns to the main flow path 3 through the second communication hole 5.

At this time, the exhaust gas can pass through only the first heat exchanger 17 to exchange heat and perform early warm-up or the like. Therefore, as compared with the case of supplying the exhaust gas to the exhaust gas recirculation device, the length of the flow path through which the exhaust gas passes through the heat exchanger is shortened, and the back pressure can be reduced.

Further, as shown in FIG. 4, when the main flow path 3 is opened by the first valve body 9, the second communication hole 5 is closed, and the valve (not shown) in the exhaust gas recirculation device is closed. , Exhaust gas does not flow into the sub-flow path 7 from the first communication hole 4, flows only through the main flow path 3, and the heat exchangers 17 and 18 are not used.

As described above, when the exhaust heat recovery device 1 of the present invention is cooled to return the exhaust gas to the exhaust gas recirculation device, high heat exchange efficiency can be obtained, and early warm-up and the like can be obtained. When performing the above, the back pressure can be lowered, and the requirements required for both can be satisfied.

In the above embodiment, the entire flow direction of the exhaust gas of the medium flow path 17a of the first heat exchanger 17 and the medium flow path 18a of the second heat exchanger 18 is partitioned by the partition member 10. Only the first communication hole 4 side may be partitioned by the partition member 10, and a part thereof may be formed so as to be able to flow to each other.

Further, in the above embodiment, the first heat exchanger 17 and the second heat exchanger 18 are integrally formed, but the first heat exchanger 17 and the second heat exchanger 18 may be formed of separate members. good.

Further, in the first flow path 11, as shown in FIGS. 2 to 5, a space 19 may be formed between the first communication hole 4 and the first heat exchanger 17, or the space 19 may be formed. Instead, the exhaust gas may flow directly into the first heat exchanger 17 after passing through the first communication hole 4.

Further, in the second flow path 12, as shown in FIGS. 2 to 5, a space 20 may be formed between the outlet 13 and the second heat exchanger 18, or the space 20 may not be formed. The exhaust gas may pass through the outlet 13 immediately after passing through the second heat exchanger 18.

[Example 2]
The exhaust heat recovery device 1 of the first embodiment is formed so that the space 19 and the space 20 are partitioned by the partition member 10 so as not to communicate with each other. However, the exhaust heat recovery device 21 of the second embodiment is shown in FIGS. 6 to 8. As described above, the third communication hole 22 is formed in the partition member 10 portion that separates the space 19 and the space 20 to communicate with each other, and the third communication hole 22 is opened and closed by the second valve body 24.

As shown in FIG. 6, when the third communication hole 22 is closed by the second valve body 24, the outlet 13 opens, and as shown in FIG. 7, the second valve body 24 is moved upward from the state of FIG. When the third communication hole 22 is opened, the outlet 13 is closed.

As shown in FIG. 6, the first valve body 9 opens the main flow path 3 and closes the second communication hole 5, and the second valve body 24 closes the third communication hole 22 to open the outlet 13. When the exhaust gas is open and a valve (not shown) in the exhaust gas recirculation device is open, the exhaust gas flows through the main flow path 3 and also flows through the first communication hole 4 to the sub-flow path 7.

The exhaust gas that has passed through the first communication hole 4 enters the first flow path 11 and passes through the first heat exchanger 17, and then turns back because the second communication hole 5 is blocked, and the second flow path 12 After moving inward and passing through the second heat exchanger 18, it flows into the exhaust gas recirculation device through the outlet 13.

At this time, the exhaust gas passes through the first heat exchanger 17 and the second heat exchanger 18 in series, is cooled, and then is supplied to the exhaust gas recirculation device to obtain high heat exchange efficiency. be able to.

Further, as shown in FIG. 7, the main flow path 3 is closed by the first valve body 9, the second communication hole 5 is opened, and the third communication hole 22 is opened by the second valve body 24. When the outlet 13 is closed, the exhaust gas flows from the main flow path 3 through the first communication hole 4 and into the sub flow path 7.

The exhaust gas that has passed through the first communication hole 4 enters the second flow path 12 through the first communication hole 11 and the third communication hole 22, and exchanges heat with the first heat exchanger 17 and the second heat exchanger 17. After passing through the vessel 18 in parallel, it passes through the third flow path 15, passes through the second communication hole 5, and returns to the main flow path 3.

At this time, the exhaust gas passes through the first heat exchanger 17 and the second heat exchanger 18 in parallel to exchange heat, and early warm-up or the like can be performed. Therefore, as compared with the first embodiment, the vertical cross-sectional area through which the exhaust gas flows is increased, the back pressure can be further lowered, and the heat exchange efficiency can be improved.

Further, as shown in FIG. 8, the first valve body 9 opens the main flow path 3, the second communication hole 5 is closed, and the second valve body 24 opens the third communication hole 22. When the outlet 13 is closed, the exhaust gas does not flow into the sub-flow path 7 through the first communication hole 4, flows only through the main flow path 3, and the heat exchangers 17 and 18 are not used.

Since the other structures are the same as those in the first embodiment, the description thereof will be omitted.

The same effect as that of the first embodiment is obtained in the second embodiment.

[Example 3]
The exhaust heat recovery device 21 of the second embodiment opens and closes the third communication hole 22 and the outlet 13 by rotating the second valve body 24, but the exhaust heat recovery device 31 of the third embodiment is As shown in FIGS. 9 to 11, only the third communication hole 22 may be opened and closed by the rotation of the second valve body 34.

As shown in FIGS. 10 and 11, when the third communication hole 22 is opened by the rotation of the second valve body 34, the outlet 13 is also left open, but the valve (not shown) is closed. As a result, the exhaust gas is not supplied to the exhaust gas recirculation device.

Since the other structures are the same as those in the second embodiment, the description thereof will be omitted.

In the third embodiment, the same effect as in the first and second embodiments is obtained.

[Example 4]
In the exhaust heat recovery devices 1, 21, 31 of the first to third embodiments, the first communication hole 4 is provided on the upstream side and the second communication hole 5 is provided on the downstream side, and the main flow path 3 is closed by the first valve body 9. From the state, the first valve body 9 was rotated in the downstream direction to open the main flow path 3, but the first communication hole 4 was provided on the downstream side and the second communication hole 5 was provided on the upstream side. From the state where the main flow path 3 is blocked by the 1-valve body 9, the first valve body 9 may be rotated in the upstream side to open the main flow path 3.

For example, as shown in FIGS. 12 to 14, the exhaust heat recovery device 1 of the first embodiment is mounted on a vehicle or the like in a state of being inverted so that the upstream side is the downstream side and the downstream side is the upstream side. You may do so.

Since the other structures are the same as those in the first to third embodiments, the description thereof will be omitted.

The same effect as in Examples 1 to 3 is obtained in Example 4 as well.

1,21,31 Exhaust heat recovery device 3 Main flow path 4 1st communication hole 5 2nd communication hole 7 Sub flow path 8 Rotating shaft 9 1st valve body 10 Partition member 11 1st flow path 12 2nd flow path 15 3rd Flow path 17 1st heat exchanger 18 2nd heat exchanger 22 3rd communication hole 24,34 2nd valve body

Claims (4)

It has a main flow path through which the exhaust gas discharged from the internal combustion engine flows, and a sub-flow path that communicates with the main flow path through the first communication hole and the second communication hole.
When a rotation shaft is provided between the first communication hole and the second communication hole, and a first valve body that opens and closes the main flow path is rotatably provided around the rotation shaft and the main flow path is opened. The second communication hole is closed by the first valve body, and the second communication hole is opened when the main flow path is closed by the first valve body.
The side portion of the first communication hole of the sub-flow path is partitioned by a partition member to form the first flow path and the second flow path, and one end of the first flow path is connected to the main flow path through the first communication hole. One end of the second flow path communicates with the exhaust gas recirculation device, and the other end of the first flow path and the other end of the second flow path are one end of the third flow path. The other end of the third flow path communicates with the main flow path through the second communication hole.
A first heat exchanger for exchanging heat between the exhaust gas and the medium is provided in the first flow path.
An exhaust heat recovery device characterized in that a second heat exchanger for exchanging heat between the exhaust gas and the medium is provided in the second flow path. A third communication hole that communicates the first flow path and the second flow path is formed at the end of the partition member on the side of the first communication hole, and the third communication hole is opened and closed by the second valve body. West,
The exhaust heat recovery device according to claim 1, wherein when the first valve body is closed, the second valve body is opened so that the first flow path and the second flow path communicate with each other. .. The first heat exchanger and the second heat exchanger are integrally formed.
At least the first communication hole side portion of the flow path through which the exhaust gas flows in the integrally formed heat exchanger is partitioned by the partition member, and the flow path through which the exhaust gas flows in the first heat exchanger and the said. The exhaust heat recovery device according to claim 1 or 2, wherein a flow path through which exhaust gas flows in the second heat exchanger is formed. The exhaust heat recovery device according to claim 1 or 2, wherein the first heat exchanger and the second heat exchanger are made of separate members.

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