JP5439312B2 - Waste heat recovery device - Google Patents

Description

  The present invention relates to an exhaust heat recovery apparatus that warms cooling water with the heat of exhaust gas.

  2. Description of the Related Art An exhaust heat recovery device that transmits heat of exhaust gas generated in an internal combustion engine to cooling water and warms the cooling water is known (see, for example, Patent Document 1 (FIG. 3)).

Patent document 1 is demonstrated based on the following figure.
As shown in FIG. 7, the exhaust heat recovery apparatus 100 includes a heat recovery unit 101 that warms cooling water with the heat of exhaust gas, and a heat recovery path 102 that is connected to the heat recovery unit 101 and sends exhaust gas to the heat recovery unit 101. A bypass circuit 103 provided on the side of the heat recovery unit 101 so as to bypass the heat recovery path 102, and a bypass circuit 103 or a bypass circuit 103 provided rotatably on the upstream side of the bypass circuit 103 and the heat recovery path 102. And a valve 104 that regulates the flow of exhaust gas by closing one of the heat recovery paths 102.

  The valve 104 closes the bypass circuit 103 until the cooling water reaches a predetermined temperature, and the exhaust gas flows toward the heat recovery path 102. As the exhaust gas flows into the heat recovery unit 101, the heat of the exhaust gas is transmitted to the cooling water in the heat recovery unit 101, and the cooling water is warmed.

  On the other hand, since the cooling water reaches a predetermined temperature, it is not necessary to warm the cooling water. The valve 104 closes the heat recovery path 102 and stops heat exchange. When the valve 104 closes the heat recovery path 102, the exhaust gas flows toward the bypass 103. The valve 104 is operated by, for example, a thermo actuator that is operated at the temperature of the cooling water.

While the exhaust gas flows through the detour 103, it is necessary to prevent the temperature of the cooling water from rising. That is, it is necessary to prevent the heat of the exhaust gas passing through the detour 103 from being transmitted to the heat recovery unit 101. In order to prevent heat from being transmitted to the heat recovery device 101, the bypass 103 is provided away from the heat recovery device 101. By providing the heat recovery device 101 and the detour route 103 apart from each other, a dead space is generated in the exhaust heat recovery device 100, and the exhaust heat recovery device 100 is enlarged.
Miniaturization of the exhaust heat recovery device is desired.

JP 2008-157211 A

  An object of the present invention is to reduce the size of the exhaust heat recovery apparatus.

According to the first aspect of the present invention, there is provided a heat recovery device that warms the cooling water with the heat of the exhaust gas, a heat recovery path that is connected to the heat recovery device and sends the exhaust gas to the heat recovery device, and bypasses the heat recovery path. And the exhaust gas flow by closing either the bypass or the heat recovery path that is pivotally provided upstream of the bypass and the heat recovery path or downstream of the bypass and the heat recovery path. In a waste heat recovery device comprising a valve that regulates the temperature and a thermoactuator that is connected to a rotating shaft that rotates the valve and that is actuated by the temperature of cooling water,
The heat recovery unit is provided on the upper surface of the detour to be in contact with the detour,
A heat transfer prevention part for preventing heat transfer from the bypass to the heat recovery unit is provided inside the bypass and at a lower part of the part on which the heat recovery unit is placed ,
The heat transfer prevention part is formed by a plate-like member joined inside the detour, and left and right side walls of the detour,
Each of the left and right side walls is provided with a communication hole that communicates the heat transfer prevention part and the outside or a louver that communicates the heat transfer prevention part and the outside,
The communication hole or the louver is different in height provided between the left side wall and the right side wall .

  In the invention which concerns on Claim 1, the heat transfer prevention part which prevents the movement of the heat | fever to a heat recovery device is provided in a detour. Since the heat transfer prevention part is provided inside the detour, the heat recovery unit can be provided in contact with the detour. By providing the heat recovery device so as to contact the detour, the exhaust heat recovery device can be downsized.

In addition, in the invention according to claim 1 , the heat recovery device is placed on the upper surface of the detour. For example, when the exhaust heat recovery device is used in a vehicle, stones may jump from the road surface toward the exhaust heat recovery device. By placing the heat recovery device on the upper surface of the detour, the heat recovery device can be protected from such stepping stones.

Furthermore, in the invention which concerns on Claim 1 , the heat transfer prevention part is formed with the plate-shaped member and the side wall of the detour. In order to form the heat transfer prevention part, it is only necessary to newly add a plate-like member, and the heat transfer prevention part can be formed with a small number of parts.

In addition, in the invention according to claim 1 , the side wall is provided with a communication hole that communicates the heat transfer prevention part with the outside or a louver that communicates the heat transfer prevention part with the outside. The heat of the exhaust gas passing through the detour is transmitted to the heat transfer prevention unit. The heat transfer prevention unit communicates with the outside through a communication hole or a louver. By releasing the heat trapped in the heat transfer prevention part to the outside from the communication hole or louver, it is possible to more reliably prevent the heat from moving to the heat recovery unit.
Further, the heat of the exhaust gas may be transmitted from the bypass to the heat transfer prevention unit. Since the heat of the exhaust gas is high, the heat escapes from the communication hole or louver provided at a high position. The heat of low temperature flows into the heat transfer prevention part from the communication hole or louver provided at the low position as much as the heat of high temperature escapes. That is, convection is generated in the heat transfer prevention part. By generating convection in the heat transfer prevention unit, heat can be efficiently discharged to the outside, and heat transfer to the heat recovery unit can be more reliably prevented.

It is a side view of the waste heat recovery device concerning the present invention. It is sectional drawing of the waste heat recovery apparatus which concerns on this invention. It is a disassembled perspective view of a heat transfer prevention part. It is a disassembled perspective view of a detour. FIG. 5 is a sectional view taken along line 5-5 in FIG. FIG. 6 is a modified embodiment diagram of FIG. 5. It is a figure explaining the basic composition of the conventional technology.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

Embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the exhaust heat recovery apparatus 10 includes an exhaust gas introduction part 11 into which exhaust gas generated in an internal combustion engine is introduced, and a heat recovery path 12 connected to an upper part on the downstream side of the exhaust gas introduction part 11. The detour path 13 provided below the heat recovery path 12 and connected to the lower downstream side of the exhaust gas introduction section 11, and the exhaust water placed on the upper surface of the detour path 13 and sent from the heat recovery path 12 The heat recovery device 14 that warms the water, the water supply pipe 16 that is connected to the heat recovery device 14 and sends cooling water into the heat recovery device 14, and the cooling water sent from the water supply tube 16 to the heat recovery device 14 is discharged. A discharge portion 17, a thermoactuator 18 that is supported by the discharge portion 17 and in which a part of the cooling water flows from the discharge portion 17, and is provided in contact with the rod 19 of the thermoactuator 18, and is biased in the clockwise direction in the drawing Heading to A rotating plate 21 is biased is provided.

  When the temperature of the cooling water in the heat recovery device 14 rises, the thermoactuator 18 advances the rod 19 toward the left of the drawing as shown by the arrow (1). The rod 19 moves forward against the force with which the rotating plate 21 is urged clockwise. As the rod 19 moves forward, the rotating plate 21 is rotated counterclockwise in the drawing. As the rotating plate 21 rotates, the rotating shaft (reference numeral 22 in FIG. 2) supported by the rotating plate 21 also rotates in the same direction. Details are described in the following figure.

  As shown in FIG. 2, a rotation shaft 22 is provided on the upstream side of the heat recovery path 12 and the detour 13 on the basis of the flow direction of the exhaust gas, and a V-shaped valve 24 is supported on the rotation shaft 22. Is done. The rotation shaft 22 is provided perpendicular to the flow of exhaust gas. The direction in which the rotation shaft 22 is provided is referred to as the width direction.

  The rotation shaft 22 is urged clockwise in the drawing by being supported by a rotation plate (FIG. 1, reference numeral 21). The valve 24 supported by the rotating shaft 22 is also urged in the clockwise direction of the drawing, that is, in the direction of closing the detour 13. The tip of the valve 24 urged in the direction to close the detour 13 is seated on a seating portion 25 as a stopper.

When the valve 24 closes the bypass circuit 13, the exhaust gas flows through the heat recovery path 12 to the heat recovery unit 14.
The heat recovery device 14 includes a core case 26 that is in contact with the bypass 13 and a heat plate 27 that is provided in the core case 26 and through which exhaust gas is passed.

  The heat of the exhaust gas flowing through the heat plate 27 is transmitted to the cooling water flowing into the core case 26, and the cooling water is warmed. The exhaust gas that has passed through the heat plate 27 is discharged to the outside through the discharge hole 28.

The detour circuit 13 provided in the lower part of the heat recovery unit 14 includes a main body 31 connected to the exhaust gas introduction unit 11 and a lid 32 covering the main body 31.
A plate-like member 33 is welded to the lid portion 32 of the bypass 13. A portion surrounded by the plate member 33 and the side wall 34 of the detour 13 is a heat transfer prevention unit 35 that prevents heat from being transferred from the detour 13 to the heat recovery unit 14. That is, the heat transfer prevention unit 35 is provided in a portion corresponding to the portion where the heat recovery unit 14 is provided.
A plurality of louvers 36 are provided on the side wall 34 of the detour 13 to communicate the heat transfer prevention unit 35 with the outside.

  When the exhaust gas continues to flow to the heat recovery unit 14 and the temperature of the cooling water rises to a predetermined temperature, the thermoactuator (FIG. 1, reference numeral 18) operates. When the thermoactuator is activated, the rod (FIG. 1, reference numeral 19) rotates the rotating shaft 22 counterclockwise. As the rotation shaft 22 rotates, the valve 24 also rotates, and the heat recovery path 12 is closed as indicated by an imaginary line.

  By closing the heat recovery path 12, the exhaust gas flows toward the detour 13. By preventing the exhaust gas from flowing to the heat recovery path 12 side, heat exchange in the heat recovery unit 14 is stopped. The heat of the exhaust gas flowing through the detour 13 prevents the heat transfer to the heat recovery unit 14 by the heat transfer prevention unit 35.

The heat recovery path 12 is provided in contact with the bypass 13. As a result, heat dissipation from the cooling water in the heat exchanger 14 can be suppressed.
That is, the heat recovery unit 14 provided in the middle of the heat recovery path 12 is also provided in contact with the bypass 13. By providing the heat recovery device 14 in contact with the bypass 13, the contact area where the core case 26 of the heat recovery device 14 comes into contact with outside air can be reduced. By reducing the amount of contact between the core case 26 and the outside air, heat radiation of the cooling water can be prevented. By preventing heat dissipation of the cooling water, the cooling water can be efficiently warmed.

  Further, the heat recovery path 12 and the detour path 13 are provided in contact with each other. By providing it in contact, it can be provided compactly, and the number of connecting members provided before and after the heat recovery path 12 can be reduced. By reducing the number of connecting members, it is possible to reduce the weight of the exhaust heat recovery apparatus 10.

  Further, in the conventional exhaust heat recovery apparatus, as shown in FIG. 7, inner wall members 105 and 105 are provided between the heat recovery path 102 side and the detour path 103 side. The inner wall members 105 and 105 are joined by welding. It is difficult to operate the welding torch in the narrow space 106 defined by the inner wall members 105 and 105, resulting in a long working time. In addition, a space for operating the welding torch is necessary, and this point has led to a further increase in the size of the exhaust heat recovery apparatus 100.

  Returning to FIG. 2, since the heat recovery path 12 and the detour path 13 are provided in contact with each other, there is no need to provide an inner wall member (see reference numeral 105 in FIG. 7) between the heat recovery path 12 and the detour path 13. By not providing the inner wall member that is difficult to join, the operation of the welding torch at the time of welding becomes easy, and the assembly work of the exhaust heat recovery apparatus 10 can be performed in a short time.

Note that although the heat recovery device 14 is placed on the upper surface of the detour 13 as an example, the heat exchanger 14 can be disposed at an arbitrary position, such as disposed on the side of the detour.
However, when the heat recovery device 14 is placed on the upper surface of the bypass 13, the following effects can be obtained.

  For example, when the exhaust heat recovery device 10 is used in a vehicle, a stone may jump from the road surface toward the exhaust heat recovery device 10. By placing the heat recovery device 14 on the upper surface of the detour 13, the heat recovery device 14 can be protected from such stepping stones.

In addition, the valve 24 can be provided not only on the upstream side of the heat recovery path 12 and the bypass 13 but also on the downstream side of the heat recovery path 12 and the bypass 13.
For example, as indicated by an imaginary line, a rotating shaft 58 is provided in the vicinity of the discharge hole 28, and the single plate-like valve 59 is supported by the rotating shaft 58. Even when the valve 59 is provided on the downstream side of the heat recovery path 12 and the bypass route 13, the same effect as that provided on the upstream side can be obtained.
The details of the formation of the heat transfer prevention part 35 will be described with reference to the next drawing.

As shown in FIG. 3, the plate-like member 33 is a plate having the same width as the inner peripheral portion of the lid portion 32, and is bent from the leg portions 38 and 38 that are in contact with the lid portion 32 and these leg portions 38 and 38. The bent portions 39 and 39 are connected to each other, and the bent portions 39 and 39 are connected to each other to be separated from the lid portion 32. A recess 42 for increasing rigidity is formed in the separation portion 41.
The concave portion 42 that is recessed toward the lid portion 32 may be a convex portion that is swollen in a direction away from the lid portion 32.

  The lid part 32 has lid part flange parts 44, 44 extending in the width direction from the side wall 34, and a recess 46 for increasing rigidity is formed in the top plate part 45 that connects the side walls 34, 34.

  The heat transfer preventing portion (FIG. 2, reference numeral 35) is formed by fitting the plate-like member 33 into the lid portion 32 and welding the plate-like member 33 over the entire circumference. The detour side wall 34 and the plate-like member 33 form a heat transfer prevention unit. In order to form the heat transfer prevention part, it is only necessary to newly add the plate member 33, and the heat transfer prevention part can be formed with a small number of parts.

  After forming the heat transfer prevention part, the cover part 32 is turned over and welded to the main body part (FIG. 2, reference numeral 31) to form a detour (FIG. 2, reference numeral 13). Details are described in the following figure.

  As shown in FIG. 4, the main body 31 has a semicircular shape, and the main body flanges 48 and 48 are extended in the width direction. The main body flange portions 48, 48 are welded together with the lid flange portions 44, 44. The detour (FIG. 2, code | symbol 13) is formed because the cover part 32 is welded to the main-body part 31. FIG.

A detour is formed by welding the lid portion 32 on which the heat transfer prevention portion (FIG. 2, reference numeral 35) is formed to the main body portion 31. Since the bypass route is divided into the lid portion 32 and the main body portion 31 and these are welded, an exhaust heat recovery device having a heat transfer prevention portion in the bypass route can be easily manufactured.
The operation of the exhaust heat recovery apparatus according to the present invention will be described in detail with reference to the following diagram.

  As shown in FIG. 5, according to the exhaust heat recovery apparatus 10 according to the present invention, the heat transfer prevention unit 35 is provided in a part corresponding to the part where the heat recovery unit 14 is provided inside the detour 13. It is done. A heat transfer prevention unit 35 that prevents heat transfer to the heat recovery unit 14 is provided in the detour 13. Since the heat transfer prevention unit 35 is provided inside the bypass 13, the heat recovery device 14 can be provided in contact with the bypass 13. By providing the heat recovery device 14 in contact with the detour 13, the exhaust heat recovery device 10 can be reduced in size.

  In addition, the plate-shaped member 33 and the side wall 34 of the detour 13 form a heat transfer prevention unit 35. In order to form the heat transfer prevention part 35, it is only necessary to newly add a plate-like member 33, and the heat transfer prevention part 35 can be formed with a small number of parts.

  In addition, the side wall 34 is provided with a louver 36 that communicates the heat transfer prevention unit 35 that communicates with the heat transfer prevention unit 35 and the outside. The heat of the exhaust gas passing through the detour 13 may be transmitted to the heat transfer prevention unit 35. The heat transfer prevention unit 35 communicates with the outside by a louver 36. By releasing the heat that can be trapped in the heat transfer prevention unit 35 from the louver 36 to the outside, it is possible to more reliably prevent the heat from moving to the heat recovery unit 14.

  Furthermore, a recess 46 is provided in a portion of the lid portion 32 that contacts the heat recovery device 14. By providing the concave portion 46, the rigidity of the lid portion 32 can be increased, and by providing the concave portion 46, the area where the heat recovery device 14 and the lid portion 32 are in contact can be reduced. By reducing the contact area, the movement of heat from the bypass 13 side to the heat recovery device 14 side can be further reduced. That is, heat transfer can be reduced while increasing rigidity.

Furthermore, it is desirable that the material of the plate-like member 33 (the material for forming the heat transfer prevention unit 35) is the same material as that of the detour 13.
In the exhaust heat recovery apparatus 10 according to the present invention, the heat transfer prevention part 35 is formed by welding the plate-like member 33 to the bypass 13. The plate-like member 33 welded in the detour 13 receives the same amount of exhaust gas heat as the detour 13 receives.
Further, by making the material of the plate-like member 33 the same as the material of the bypass 13, the thermal expansion coefficient of the plate-like member 33 and the thermal expansion coefficient of the bypass 13 are the same.

That is, since the amount of heat received from the heat of the exhaust gas is the same and the coefficient of thermal expansion is the same, the amount of expansion due to heat is the same in the plate-like member 33 and the bypass 13.
If the plate member is provided outside the detour, the amount of heat received by the plate member is smaller than that of the detour. Since the amount of heat received by the plate member is small, the expansion amount of the plate member is smaller than the expansion amount of the detour. Since only the detour is relatively extended, a load is applied to the welded portion between the detour and the plate-like member.

According to the exhaust heat recovery apparatus according to the present invention, it is possible to reduce the load on the welded portion 49 between the detour 13 and the plate-like member 33 because the expansion amount is the same. By reducing the load, it is possible to extend the life of the exhaust heat recovery apparatus 10 as compared with the case where the heat transfer prevention unit 35 is provided outside the detour 13.
The exhaust heat recovery device can also be formed as described in the next figure.

  As shown in FIG. 6, in the exhaust heat recovery device 50, communication holes 53 and 54 are provided in the side wall 52 of the bypass 51. The communication holes 53 and 54 are provided at different heights.

  The heat of the exhaust gas may be transmitted from the bypass 51 to the heat transfer prevention unit 56. Since the heat of the exhaust gas is high, as shown by an arrow (2), the heat escapes from the communication hole 53 provided at a high position. As the high temperature heat escapes, the low temperature heat flows into the heat transfer preventing portion 56 from the communication hole 54 provided at the low position as indicated by the arrow (3). That is, convection occurs in the heat transfer prevention unit 56. By generating convection in the heat transfer prevention unit 56, heat can be efficiently discharged to the outside, and heat transfer to the heat recovery unit 14 can be more reliably prevented.

Moreover, even if it is such an exhaust heat recovery apparatus 50, naturally, the effect of this invention that size reduction of the exhaust heat recovery apparatus 50 can be acquired, preventing the movement of heat.
Although the communication holes 53 and 54 have been described as an example, convection can be generated in the heat transfer preventing portion 56 by changing the height even for the louver (FIG. 5, reference numeral 36). That is, the shape of the hole provided in the side wall is not limited to a round hole.

  The exhaust heat recovery apparatus according to the present invention can also be applied to an EGR (Exhaust Gas Recirculation) cooler, and the application is not limited to these.

  The exhaust heat recovery apparatus of the present invention is suitable for a hybrid vehicle.

  DESCRIPTION OF SYMBOLS 10, 50 ... Waste heat recovery apparatus, 12 ... Heat recovery path, 13, 51 ... Detour, 14 ... Heat recovery device, 18 ... Thermo actuator, 22 ... Rotating shaft, 24 ... Valve, 33 ... Plate-shaped member, 34 , 52 ... side walls, 35, 56 ... heat transfer prevention parts, 36 ... louvers, 53, 54 ... communication holes.

Claims (1)

A heat recovery unit that heats the cooling water with the heat of the exhaust gas, a heat recovery path that is connected to the heat recovery unit and sends the exhaust gas to the heat recovery unit, and a detour that is provided to bypass the heat recovery path; A valve that is rotatably provided upstream of the bypass and the heat recovery path or downstream of the bypass and the heat recovery path, and restricts the flow of the exhaust gas by closing either the bypass or the heat recovery path. And an exhaust heat recovery device comprising a thermoactuator connected to a rotating shaft for rotating the valve and operated by the temperature of the cooling water,
The heat recovery unit is provided on the upper surface of the detour to be in contact with the detour,
A heat transfer prevention part for preventing heat transfer from the bypass to the heat recovery unit is provided inside the bypass and at a lower part of the part on which the heat recovery unit is placed ,
The heat transfer prevention part is formed by a plate-like member joined inside the detour, and left and right side walls of the detour,
Each of the left and right side walls is provided with a communication hole that communicates the heat transfer prevention part and the outside or a louver that communicates the heat transfer prevention part and the outside,
The exhaust heat recovery apparatus , wherein the communication hole or the louver is provided with different heights on the left side wall and the right side wall .

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