JP6425478B2 - Exhaust heat recovery system - Google Patents

Description

  The present invention relates to an exhaust heat recovery system that exchanges heat between an exhaust gas discharged from an internal combustion engine and a heat exchange medium.

  2. Description of the Related Art An exhaust heat recovery apparatus is known that performs heat exchange between an exhaust gas of an internal combustion engine and a heat exchange medium such as cooling water to recover exhaust heat. This exhaust heat recovery device is provided with a switch valve that can be opened and closed at the outlet of the exhaust pipe. Further, the exhaust heat recovery apparatus includes a heat exchange path extending from a branch port provided inside the exhaust pipe to the exhaust port provided outside the exhaust pipe through the heat exchange unit.

  In such an exhaust heat recovery apparatus, when the switching valve of the exhaust pipe is closed, the exhaust gas mainly exchanges heat through the heat exchange path. On the other hand, when the heat exchange is not required, the switching valve of the exhaust pipe is opened. At this time, since the exhaust gas mainly flows through the exhaust pipe whose resistance is lower than that of the above-described heat exchange path, the amount of exhaust flowing through the heat exchange path can be reduced to suppress the heat exchange.

  However, in such an exhaust heat recovery apparatus, even when the switching valve of the exhaust pipe is opened, part of the exhaust gas flows in the heat exchange path to perform heat exchange. This is because the exhaust gas flowing through the exhaust pipe produces a venturi effect, and the exhaust is extracted from the outlet, resulting in the flow of the exhaust in the heat exchange path. By this, there existed a possibility that heat exchange might be performed to an unnecessary case.

  Therefore, in the exhaust heat recovery apparatus described in Patent Document 1 below, when the on-off valve is opened, a part of the exhaust gas is recirculated, and a vortex is generated in the vicinity of the exhaust port that is the exhaust gas outlet from the heat exchange unit. I am doing it. Due to the effect of the vortex flow, it is possible to suppress a reduction in the exhaust gas being drawn out from the exhaust port by the flow of the exhaust gas in the exhaust pipe.

JP 2014-34963 A

  However, even when the configuration as described in Patent Document 1 is adopted, the phenomenon of exhaust gas being drawn out from the exhaust port can not be completely prevented, and exhaust gas extraction suppressing means is more effective. Is required.

  The present invention has been made in view of such problems, and its object is to open the switch to prevent the exhaust gas from flowing to the heat exchange channel, and the communication port at the end of the heat exchange channel. It is an object of the present invention to provide an exhaust heat recovery apparatus capable of more reliably suppressing the exhaust gas withdrawal through the

In order to solve the above problems, an exhaust heat recovery apparatus according to the present invention is an exhaust heat recovery apparatus that performs heat exchange between an exhaust gas discharged from an internal combustion engine and a heat exchange medium, and flows from the upstream side An inner member forming at least a part of a main flow path connecting an inlet for receiving exhaust gas and a main delivery port for discharging the received exhaust gas downstream, and arranged so as to surround the inner member, and Between the outer member forming the heat exchange flow path between the heat exchange flow path, the heat exchange flow path between the exhaust gas and the heat exchange medium, and the main flow path A non-recovery mode in which the received exhaust gas is allowed to pass and flowed to the main delivery port; a heat recovery mode in which the exhaust gas received in the main flow channel is flowed through the heat exchange flow path to a secondary delivery port different from the main delivery port; And a switch for switching the A buffer chamber is provided between the heat exchange flow passage and the secondary delivery port, and the buffer chamber is formed such that exhaust gas flowing through the primary flow path flows in from the secondary delivery port in the non-recovery mode. A communication port connecting the heat exchange flow path and the buffer chamber is provided in a partition member that separates the heat exchange flow path and the buffer chamber, and the partition member flows from the secondary delivery port into the buffer chamber in the non-recovery mode. at least a portion of the abutting exhaust gas in the partition member, directing portion directing the communication port to the buffer chamber side than the communication port as Ru flowing at a predetermined distance are formed.

According to the present invention, the partition member, such that at least a portion of the exhaust gas in contact with the partition member flows into the buffer chamber from the sub outlet port in the non-recovery mode, Ru flows at a predetermined distance from the communication opening By forming the directing portion, it is possible to suppress the exhaust gas from flowing into the buffer chamber from the heat exchange flow path side. Especially in the case of the present invention, substantially by the exhaust gas because the exhaust gas flowing from the secondary outlet to the buffer chamber is flow at a communication port and a predetermined distance, from the downstream side as communication port is adopted any form Can be closed. Therefore, when it is intended that the switching device be opened and the exhaust gas not flow in the heat exchange flow path, exhaust gas extraction via the communication port at the end of the heat exchange flow path can be suppressed more reliably.

In the waste heat recovery apparatus according to the present invention is also directed portion, first directing the flow direction of the exhaust gas flowing along the partition member after the contact with the partition member from the communication port in a direction away into the buffer chamber side It is also preferred to have a wall.

In this preferred embodiment, because it has a first wall portion formed to detach the downstream direction abuts exhaust gas in the partition member from the communication port, direct to reliably exhaust gas in contact with the partition member The exhaust gas can be removed from the communication port and covered with the exhaust gas over the entire area of the communication port.

In the exhaust heat recovery apparatus according to the present invention also is directed portion, Oite exhaust gas is formed in the portion abutting against the partition member, the flow direction of the exhaust gas in contact with the partition member toward the first wall portion It is also preferred to have a second wall directed to form a curved flow .

In this preferred embodiment, the second wall portion, the exhaust gas flowing toward the partition member to form a curved flow as smoothly diverted along the partition member, also the exhaust gas flow in the first wall portion Can be smoothly converted to the desired direction described above.

In the exhaust heat recovery apparatus according to this embodiment, the first wall portion is provided with a pair so as to sandwich the second wall portion, the second wall portion, the exhaust gas flowing toward the partition member of the pair It is also preferable that it is formed to be distributed to one wall.

  In this preferred embodiment, the exhaust gas is distributed by the second wall portion, so that the wall can be reliably formed by the exhaust gas even when the first wall portion is provided in a pair.

  According to the present invention, when it is intended that the switching device is opened and the exhaust gas is not allowed to flow in the heat exchange flow path, the exhaust gas extraction via the communication port at the end of the heat exchange flow path can be suppressed more reliably. It is possible to provide an exhaust heat recovery system that can

It is a perspective view showing the appearance of the exhaust heat recovery system which is an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a cross section near the central axis of the exhaust heat recovery system shown in FIG. 1; It is sectional drawing which shows the III-III cross section of FIG. It is a fragmentary sectional view for demonstrating the orientation part shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. In order to facilitate understanding of the description, the same constituent elements in the drawings are denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  An exhaust heat recovery apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing a schematic configuration of an exhaust heat recovery apparatus HE according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a cross section near the central axis of the exhaust heat recovery system shown in FIG.

  The exhaust heat recovery apparatus HE is mounted, for example, on a car and performs heat exchange between the exhaust gas discharged from the internal combustion engine of the car and the heat exchange medium. The exhaust heat recovery apparatus HE is provided with a receiving port HEa for receiving the exhaust gas flowing from the upstream side, and a delivery port HEb for delivering the received exhaust gas to the downstream side.

  The exhaust heat recovery apparatus HE includes an inner cylinder 10 (inner member), an outer cylinder 20 (outer member), a medium inlet 21, a medium outlet 22, a switching valve unit 30 (switch), and a shell 40. And. The inner cylinder 10 forms a part of a main flow passage ZA connecting the inlet HEa and the outlet HEb.

  The outer cylinder 20 is disposed so as to coaxially surround the inner cylinder 10 and forms a heat exchange flow path with the inner cylinder 10. The medium inlet portion 21 is a portion serving as an inlet for supplying the heat exchange medium to the heat exchanger 50 in the heat exchange flow channel. The medium outlet portion 22 is a portion which is supplied from the medium inlet portion 21 and serves as an outlet for discharging the heat exchange medium which has performed heat exchange with the exhaust gas. As a heat exchange medium, a liquid used for cooling an internal combustion engine is used.

  The switching valve unit 30 is provided on the downstream side of the inner cylinder 10. The downstream end of the switching valve unit 30 forms a main delivery port 30a. The switching valve unit 30 has a cylindrical portion 30 b and a rotary valve body 30 c. By rotating the rotary valve body 30c, the main delivery port 30a can be closed or opened.

  The outer cylinder 20 is disposed so as to share the central axis with the inner cylinder 10, and the inner diameter of the outer cylinder 20 is configured to be larger than the outer diameter of the inner cylinder 10. Therefore, a space is formed between the inner cylinder 10 and the outer cylinder 20 to form the heat exchange flow path ZB.

  The upstream end of the outer cylinder 20 is narrowed and joined to the inner cylinder 10 so as to connect the inner cylinder 10 and the outer cylinder 20. Therefore, the upstream end of the outer cylinder 20 closes the upstream end side of the heat exchange flow path ZB. In the present embodiment, the upstream end of the outer cylinder 20 is squeezed and joined to the inner cylinder 10. However, the bonding mode between the outer cylinder 20 and the inner cylinder 10 is not limited thereto, and for example, another component may be interposed. May be joined together.

  The heat exchanger 50 is disposed in the heat exchange flow path ZB. The heat exchanger 50 is disposed so as to surround the inner cylinder 10 in the heat exchange flow path ZB, has a cylindrical outer shape, and performs heat exchange between the exhaust gas and the heat exchange medium. .

  The heat exchanger 50 is disposed to be separated from the inner cylinder 10 at a predetermined distance, and is also arranged to be separated from the outer cylinder 20 at a predetermined distance. By arranging the heat exchanger 50 in this manner, the first heat exchange flow path ZB1 is formed between the heat exchanger 50 and the inner cylinder 10, and between the heat exchanger 50 and the outer cylinder 20. The second heat exchange flow path ZB2 is formed in

  At the downstream end of the inner cylinder 10, a side outlet 101 for flowing out the exhaust gas from the main flow passage ZA to the first heat exchange flow passage ZB1 is formed. The side outlet 101 is formed so that the side surface of the inner cylinder 10 is open in the vicinity of the downstream end of the heat exchange flow path ZB. In addition, as a formation aspect of the side outflow port 101, it is not necessarily restricted to the aspect which the side surface of the inner cylinder 10 opens, and makes an exhaust gas flow out to the 1st heat exchange flow path ZB1 from the main flow path ZA. If possible, it can be in various aspects.

  Between the inner cylinder 10 and the outer cylinder 20, on the downstream side, the downstream end of the first heat exchange flow passage ZB1 is closed so as to lead the exhaust gas flowing out from the side outlet 101 to the first heat exchange flow passage ZB1. An end plate 25 (partition member) is disposed. The downstream end plate 25 is disposed to connect the inner cylinder 10 and the outer cylinder 20 downstream of the side outlet 101.

  The downstream end of the outer cylinder 20 is covered by a shell 40. A gap is provided between the downstream end of the switching valve unit 30 and the shell 40, and this gap functions as the sub delivery port 401.

  A space between the shell 40 and the inner cylinder 10 and the switching valve unit 30 is configured as a buffer chamber ZC. A communication port 251 is provided in the downstream end plate 25 so that the exhaust gas flows from the heat exchange flow path ZB to the buffer chamber ZC.

  With the above-described configuration, the exhaust gas received in the main flow passage ZA is allowed to pass through the switching passage 30 by opening and closing the switching valve unit 30, and the exhaust gas received in the main flow passage ZA is thermally transferred. A heat recovery mode of flowing to the sub-delivery port 401 via the exchange flow path ZB is selectively enabled.

  In the exhaust heat recovery apparatus HE, as described above, the first heat exchange flow path ZB1 is formed between the heat exchanger 50 and the inner cylinder 10, and the second heat exchange flow path ZB1 is formed between the heat exchanger 50 and the outer cylinder 20. The heat exchange flow path ZB2 is formed. In the exhaust heat recovery apparatus HE, the side outlet 101 from which the exhaust gas flows from the main flow passage ZA to the first heat exchange flow passage ZB1 is formed on the upstream side, and the main delivery port 30a of the first heat exchange flow passage ZB1 is formed on the downstream side. It is done.

  In the exhaust heat recovery apparatus HE, the exhaust gas flows from the side outlet 101 into the heat exchange channel ZB in the heat recovery mode. The exhaust gas which has flowed out to the heat exchange flow path ZB flows from the first heat exchange flow path ZB1 in the radial direction from the inside to the outside of the heat exchanger 50 to reach the second heat exchange flow path ZB2, Heat exchange is performed in the heat exchanger 50.

  In the present embodiment, the side outlet 101 from which the exhaust gas flows from the main flow passage ZA to the first heat exchange flow passage ZB1 is formed at the end of the first heat exchange flow passage ZB1 at the main delivery port 30a side. The side outlet 101 can be formed in the vicinity of the switching valve unit 30. As described above, when the switching valve unit 30 is operated to form the exhaust gas flow in the non-recovery mode by devising the arrangement of the side outlet 101, the heat exchange flow path ZB is passed from the side outlet 101. Thus, it is possible to reduce the pressure difference between the path leading to the sub delivery port 401 and the main flow passage ZA. Therefore, the exhaust gas can not flow into the heat exchange flow path ZB side in the non-recovery mode, and can flow from the main delivery port 30a toward the delivery port HEb via the main flow path ZA as it is.

  In the present embodiment, the exhaust gas is designed not to enter the heat exchange flow path ZB in the non-recovery mode. As described above, the communication port 251 connecting the heat exchange flow path ZB and the buffer chamber ZC is provided in the downstream end plate 25 that divides the heat exchange flow path ZB and the buffer chamber ZC.

The exhaust gas flowing from the secondary delivery port 401 into the buffer chamber ZC in the non-recovery mode abuts on the downstream end plate 25. At least a portion of the abutting exhaust gas on the downstream side end plate 25 is configured so as Ru flowing at a communication port 251 by a predetermined distance.

  This configuration will be described with reference to FIG. As shown in FIG. 3, a directing portion 252 is provided at a portion where the exhaust gas of the downstream end plate 25 abuts. In the non-recovery mode, the directing unit 252 can continue the exhaust gas flowing into the buffer chamber ZC from the sub delivery port 401 and contacting the downstream end plate 25 at a predetermined distance from the communication port 251. It is a part to direct.

  The orientation unit 252 will be further described with reference to FIG. As shown in FIG. 4, the directing portion 252 includes a first wall 252 a and a second wall 252 b.

  The first wall 252 a is provided in the vicinity of the pair of communication ports 251. The first wall 252a is a curved wall formed to separate the exhaust gas in contact with the downstream end plate 25 from the communication port 251 in the downstream direction (upward direction in FIG. 4).

  The second wall portion 252 b is formed at a substantially central portion between the pair of communication ports 251. The second wall 252 b is formed such that the exhaust gas flowing toward the downstream end plate 25 forms a curved flow and travels in the direction of the first wall 252 a.

  When the switching valve unit 30 is operated in the heat recovery mode to close the downstream end of the main flow passage ZA, the exhaust gas flows from the side outlet 101 into the heat exchange flow passage ZB. In the present embodiment, the exhaust gas flowing out to the heat exchange flow path ZB flows from the first heat exchange flow path ZB1 in the radial direction from the inside to the outside of the heat exchanger 50 and reaches the second heat exchange flow path ZB2. Thus, the exhaust gas can be distributed substantially uniformly throughout the entire heat exchanger 50 to perform heat exchange with the heat exchange medium. Therefore, the exhaust gas can be spread over the entire heat exchanger 50 in the heat recovery mode, and the heat exchange efficiency can be enhanced.

  The above embodiment is merely an example, and various omissions, replacements, and changes can be made without departing from the scope of the invention.

10: inner cylinder 20: outer cylinder 21: medium inlet 22: medium outlet 25: downstream end plate 30: switching valve unit 30a: main outlet 30b: cylindrical portion 30c: rotary valve body 40: shell 50: thermal Exchanger 101: side outlet 251: communication port 252: direction part 252a: first wall 252b: second wall 401: secondary outlet HE: exhaust heat recovery device HEa: inlet HEb: outlet ZA: Main flow path ZB: heat exchange flow path ZB1: first heat exchange flow path ZB2: second heat exchange flow path ZC: buffer chamber

Claims (4)

An exhaust heat recovery apparatus for exchanging heat between an exhaust gas discharged from an internal combustion engine and a heat exchange medium, comprising:
An inner member forming at least a part of a main flow path connecting an inlet for receiving exhaust gas flowing from the upstream side, and a main delivery port for discharging the received exhaust gas downstream;
An outer member disposed so as to surround the inner member and forming a heat exchange channel with the inner member;
A heat exchanger disposed so as to surround the inner member in the heat exchange flow path and performing heat exchange between the exhaust gas and the heat exchange medium;
The non-recovery mode in which the exhaust gas received in the main flow passage is allowed to pass and flowed to the main delivery port, and the exhaust gas received in the main flow passage is sent via the heat exchange flow passage. A switch for switching between the heat recovery mode to flow to the outlet, and
A buffer chamber is provided between the heat exchange flow passage and the sub delivery port, and the buffer chamber is formed such that exhaust gas flowing through the main flow path flows in from the sub delivery port in the non-recovery mode.
A communication port for connecting the heat exchange channel and the buffer chamber is provided in a partition member which divides the heat exchange channel and the buffer chamber,
In the partition member, at least a portion of the exhaust gas flowing from the sub delivery port into the buffer chamber in the non-recovery mode and in contact with the partition member is closer to the buffer chamber than the communication port. the orientation section to direct as Ru flowing at a predetermined distance is formed from the exhaust heat recovery apparatus according to claim. The orientation section, to have a first wall portion for directing the flow direction of the exhaust gas flowing along said partition member after the contact with the partition member from said communication port in a direction away into the buffer chamber side An exhaust heat recovery system according to claim 1, characterized in that. Wherein directing portions, the Oite exhaust gas in the partition member is formed in the abutting portion, the flow direction of the exhaust gas abuts against the partition member so as to form a curved flow toward the first wall portion The exhaust heat recovery system according to claim 2, further comprising a second wall for directing . The first wall portion is provided in a pair so as to sandwich the second wall portion,
The second wall portion, the exhaust heat recovery apparatus according to claim 3, characterized in that it is formed so as to distribute the exhaust gas flowing toward the partition member to the pair of the first wall portion.

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