KR20170116577A - Exhaust heat recovery device - Google Patents

Abstract

The exhaust pipe of the present invention comprises a first pipe through which exhaust gas from an engine flows, a second pipe which communicates with the first pipe and bypasses the first pipe, and a second pipe which is disposed inside the second pipe A heat recovery device for recovering the heat of the exhaust gas by heat exchange between the cooling water circulating in the exhaust pipe and the cooling water circulating in the exhaust pipe, and a heat recovery device installed at a connection portion between the first pipe and the second pipe, And an electric conduction suppressing mechanism for suppressing the transfer of heat to the piping.

Description

[0001] EXHAUST HEAT RECOVERY DEVICE [0002]

The present invention relates to an array recovery apparatus.

Japanese Patent Application Laid-Open Publication No. 2012-247132 discloses an exhaust gas recirculation system that includes a first flow path (first piping) through which exhaust gas from an engine flows, a second flow path (second piping) branched from the first flow path, And a heat recovery device disposed within two flow paths. Further, the heat recovery device has a discharge hole for allowing the cooling water flowing on the upstream side of the heat recovery device to be larger than the cooling water flowing on the downstream side of the heat recovery device. Thereby, the cooling water in the heat recovery unit can be made to flow in accordance with the temperature gradient of the cooling water.

In this arrangement, the first flow path is heated by the exhaust gas flowing through the first flow path, so that the heat of the first flow path is transmitted to the second flow path, and the temperature of the cooling water in the heat recovery device rises. In particular, for example, when the engine is stopped, the circulation of the cooling water in the heat recovery unit is stopped, so that the cooling water stays in the heat recovery unit and the cooling water in the heat recovery unit may boil up. In this case, there is a possibility that an abnormal sound due to boiling of the cooling water occurs in the heat recovery machine. For this reason, it is preferable that the arrangement recovery apparatus has a structure capable of suppressing the boiling of the cooling water in the heat recovery apparatus.

The present invention provides an arrangement recovery device capable of suppressing boiling of cooling water in a heat recovery device.

An apparatus for recovering an exhaust gas according to a first aspect of the present invention includes a first pipe through which exhaust gas from an engine flows, a second pipe which communicates with the first pipe and bypasses the first pipe, A heat recovery device disposed in the interior of the second pipe for recovering the heat of the exhaust gas by heat exchange between the cooling water circulating inside the exhaust pipe and the exhaust gas and a heat recovery device installed at a connection portion between the first pipe and the second pipe, And an electric conduction suppressing mechanism for suppressing the transfer of heat from the first pipe to the second pipe.

In the exhaust gas recirculation apparatus of the above construction, the second pipe communicates with the first pipe through which the exhaust gas from the engine flows, and the second pipe bypasses the first pipe. A heat recovery device is disposed inside the second pipe. Thereby, heat exchange between the cooling water circulating in the heat recovery unit and the exhaust gas can be performed, and the heat of the exhaust gas can be recovered by the heat recovery unit.

However, since the exhaust gas of the engine flows through the first pipe, the first pipe is heated by the exhaust gas. Therefore, when the heat of the first pipe is directly transferred to the second pipe connected to the first pipe, the temperature of the cooling water in the heat exchanger is raised by the heat transmitted to the second pipe.

Here, the connection portion between the first pipe and the second pipe is provided with an electric heat prevention mechanism, and the transfer of heat from the first pipe to the second pipe is suppressed by the heat transfer suppressing mechanism. As a result, excessive temperature rise of the second pipe due to the heat of the first pipe is suppressed, so that the boiling of the cooling water in the heat recoverer can be suppressed.

According to a second aspect of the present invention, in the first aspect, the heat transfer suppressing mechanism has a heat insulating material, and the second pipe is connected to the first pipe via the heat insulating material.

In the arrangement recovery apparatus of the above configuration, since the second pipe is connected to the first pipe through the heat insulating material of the heat transfer suppressing mechanism, heat transfer of the heat of the first pipe to the second pipe can be suppressed by the heat insulating material. Therefore, the boiling of the cooling water in the heat recovery unit can be suppressed to a simple configuration.

In the arrangement recovery apparatus according to the third aspect of the present invention, in the first aspect or the second aspect, a connection portion of the first piping with the second piping is provided with: Wherein the heat conduction restriction mechanism is formed on a periphery of the communication hole of the first pipe and is located outside the communication hole on the outer side of the first pipe And a second flange formed at a connecting portion between the folded first flange and the first pipe in the second pipe and connected to the first flange.

In the above-described configuration, a communication hole communicating the inside of the first pipe and the inside of the second pipe is formed in the connection portion of the first pipe. A first flange constituting an electric conduction limiting mechanism is formed at the periphery of the communication hole, and a second flange constituting a heat transfer suppressing mechanism is formed at a connection portion of the second pipe. The first flange is folded back to the outside of the communication hole on the outer side of the first pipe, and the second flange is connected to the first flange. Therefore, the heat transfer path from the first pipe to the second pipe can be set longer by the first flange and the second flange. This makes it possible to effectively suppress the boiling of the cooling water in the heat recovery unit.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the heat transfer suppressing mechanism includes a bolt and a nut, and the first pipe and the second pipe are connected to the bolt And is connected by being fastened by the nut.

In the exhaust heat recovery apparatus of the above construction, since the first pipe and the second pipe are fastened and connected by the bolts and nuts of the heat transfer suppression mechanism, the boiling of the cooling water in the heat recovery device can be suppressed to a simpler structure . That is, when the second pipe is directly fastened to the first pipe by the bolt and the nut, the adhesion of the fastening portion at the connection portion between the first pipe and the second pipe is increased, but the connection between the first pipe and the second pipe The adhesion of the non-fastened portions in the non-fastened portions is relatively low. Therefore, the heat conduction of the unfastened portion at the connection portion between the first pipe and the second pipe becomes relatively low. As a result, the heat of the first pipe can be prevented from being transferred to the second pipe at a portion where the first pipe and the second pipe are not joined at the connection portion. Therefore, excessive temperature rise of the second pipe due to the heat of the first pipe is suppressed, so that the boiling of the cooling water in the heat recoverer can be suppressed to a simpler configuration.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the upstream end and the downstream end of the second pipe are connected to the first pipe.

In the above arrangement, since the upstream end and the downstream end of the second pipe are connected to the first pipe, the second pipe can be connected to the first pipe in parallel. This makes it more difficult for the heat recovery device to be affected by the radiant heat of the first pipe, as compared with a structure in which the second pipe and the heat recovery device are annularly arranged outside the first pipe. Therefore, it is possible to provide an effective arrangement structure for suppressing the boiling of the cooling water in the heat recovery unit.

In the sixth aspect of the present invention, in the fifth aspect, the heat transfer suppressing mechanism is provided in the connecting portion between the upstream end portion and the first pipe, the downstream end portion, and the connecting portion between the first pipe have.

In the above-described configuration, the heat of the first pipe is prevented from being transferred from the upstream side and the downstream side of the second pipe to the heat collecting device. This makes it possible to further suppress the boiling of the cooling water in the heat recovery unit.

The exhaust gas recirculation device according to the seventh aspect of the present invention includes a first pipe through which exhaust gas from an engine flows, a second pipe branched from the first pipe, and a header plate, A heat recovery unit mounted on an opening of the second pipe to close the opening and recover heat of the exhaust gas by heat exchange between the cooling water circulating the inside and the exhaust gas from the second pipe, And a heat recovery suppressing mechanism provided at a connection portion of the recovery device for suppressing the transfer of heat from the second pipe to the heat recovery device, wherein the heat recovery device has a flow path through which cooling water passes through the outer peripheral portion, And an outer peripheral portion of the header plate welded together with an opening end portion of the second pipe to an outer wall surface constituting the header pipe All.

In the exhaust gas recycling apparatus having the above structure, the heat recovery device is mounted on the second pipe branched from the first pipe through which the exhaust gas from the engine flows, so as to close the opening. Thereby, heat exchange between the cooling water circulating in the heat recovery unit and the exhaust gas can be performed, and the heat of the exhaust gas can be recovered by the heat recovery unit.

However, since the exhaust gas of the engine flows through the first pipe and the second pipe, the first pipe and the second pipe are heated by the exhaust gas. Therefore, when the heat of the first pipe and the second pipe is directly transferred to the heat recovery device connected to the second pipe, the temperature of the cooling water in the heat recovery device is raised by the heat.

Here, a heat transfer suppressing mechanism for suppressing the transfer of heat from the second pipe to the heat recovery device is provided at the connection portion between the second pipe and the heat recovery device. That is, the outer circumferential portion of the heat recovery device is provided with a flow passage through which the cooling water passes, and the outer peripheral portion of the header plate is welded to the outer wall surface constituting the flow path, together with the opening end portion of the second pipe.

Therefore, the heat transfer path from the welded portion to the cooling water in the heat recovery unit can be set long, and the excessive temperature rise of the cooling water by the heat of the second pipe can be suppressed, so that the boiling of the cooling water can be suppressed. Further, since the temperature immediately after the welding of the welding portion can be reduced by the cooling water, the lowering of the bonding strength at the welding portion can be suppressed.

Further, according to the arrangement recovery apparatus of the eighth aspect of the present invention, in the seventh aspect, the outer peripheral portion of the header plate extends toward the upstream side in the mounting direction of the heat recovery device to the opening of the second piping.

In the above arrangement, the outer peripheral portion of the header plate extends toward the upstream side in the mounting direction of the second piping of the heat recovery unit to the opening. This makes it possible to efficiently set the length of the heat transfer path from the welding portion to the cooling water, as compared with the configuration in which the outer peripheral portion of the header plate is not extended toward the upstream side in the mounting direction of the second pipe of the heat recovery device And it is possible to effectively suppress the boiling of the cooling water in the heat recovery unit.

Embodiments of the present invention will be described in detail based on the following drawings
Fig. 1 is a cross-sectional view showing a main part of an array recovery apparatus according to the first embodiment. Fig.
Fig. 2 is an explanatory view for explaining the overall configuration of the arrangement recovery apparatus shown in Fig. 1. Fig.
Fig. 3 is a cross-sectional view corresponding to Fig. 1 showing a modification of the heat transfer suppression mechanism shown in Fig. 1. Fig.
4 is a cross-sectional view showing the main part of the array recovery apparatus according to the second embodiment.
Fig. 5 is a cross-sectional view showing the main part of the array recovery apparatus according to the third embodiment. Fig.
Fig. 6 is a cross-sectional view showing an example in which the heat transfer inhibiting mechanism shown in Fig. 1 is applied to another sorting device. Fig.
Fig. 7 is a cross-sectional view showing the main part of the array recovery apparatus according to the fourth embodiment. Fig.

(First Embodiment)

Hereinafter, the exhaust heat recovery apparatus 10 according to the first embodiment will be described with reference to Figs. 1 and 2, and then the heat transfer suppression mechanism 50 applied to the exhaust heat recovery apparatus 10 will be described . In the following description, the upstream side and the downstream side of the exhaust gas flow direction may be simply referred to as " upstream side " and " downstream side ", respectively.

(With respect to the array recovery apparatus 10)

2, the exhaust heat recovery apparatus 10 recovers heat of the exhaust gas of the engine 12 of an automobile by heat exchange with cooling water in a heat recovery device 40 to be described later, It is a device used for promoting warming.

As shown in Fig. 1, the array recovery apparatus 10 has a first pipe 20 in the shape of a pipe. In this embodiment, the first pipe 20 is formed in a pipe shape by joining members (for example, divided into two parts) in the circumferential direction of the first pipe 20 by welding or the like. The outer shape of the first pipe 20 may be either a circular shape or a rectangular shape. In the present embodiment, the first pipe 20 is formed into a rectangular pipe shape. Therefore, the first pipe 20 includes four side walls 20S. 2, the first pipe 20 is connected to the engine 12 and constitutes an exhaust path for the exhaust gas flowing out of the engine 12. [ In Fig. 2, the flow of the exhaust gas in the first pipe 20 is indicated by an arrow A in Fig. A catalytic converter 14 is provided on the upstream side of the first pipe 20 and the catalytic converter 14 is configured to purify the exhaust gas passing through the built-in catalyst.

The first pipe 20 is connected to the pipe-shaped second pipe 30 at the branching portion 20A on the downstream side of the catalytic converter 14. [ That is, the second pipe 30 is branched from the first pipe 20 at the branching portion 20A and the second pipe 30 is branched from the branching portion 20A of the first pipe 20 And is connected to the first pipe 20 in the merging portion 20B on the downstream side. The second pipe 30 is connected to the first pipe 20 in parallel to constitute an exhaust path that bypasses the first pipe 20. 1, in the branching portion 20A of the first pipe 20, a portion of the side wall 20S of the first pipe 20, which is one of the four side walls 20S, Quot; communication hole " for communicating the inside of the first pipe 30 and the inside of the second pipe 30 are formed. The merging portion 20B of the first pipe 20 is formed with a merging hole 24 as a "communication hole" for communicating the inside of the first pipe 20 and the inside of the second pipe 30 .

As shown in FIG. 2, a heat recovery device 40 is provided in the second pipe 30 at an intermediate position of the second pipe 30. A cooling water circulation path 16 for circulating cooling water between the heat recovery device 40 and the engine 12 is connected to the heat recovery device 40. Cooling water is circulated in the cooling water circulation path 16 by the operation of a water pump (not shown) driven by the power of the engine 12 (the flow of cooling water is indicated by an arrow B in Fig. 2) . Thereby, the heat recovery device 40 recovers the heat of the exhaust gas to the cooling water by heat exchange between the exhaust gas and the cooling water, and uses the heat to promote the warming of the engine 12 or the like.

Further, for example, when the engine 12 is stopped immediately after the start of the engine 12 or when the ignition switch of the automobile is turned off, cooling water is not circulated in the cooling water circulation path 16. When the engine 12 is stopped by the intermittent operation of the engine 12 in the case where the exhaust heat recovery apparatus 10 is applied to an automobile of a hybrid car, It is configured not to circulate.

A flow path switching valve 18 for opening and closing the flow path in the first pipe 20 is provided in the first pipe 20 between the branching portion 20A and the merging portion 20B , &Quot; channel switching plate (b) "). The flow path switching valve 18 is controlled by an unillustrated ECU (control device). The flow path switching valve 18 is operated under the control of the ECU to open and close the flow path between the branching portion 20A and the merging portion 20B by the flow path switching valve 18. [ For example, when the warming up of the engine 12 is promoted, the flow path between the branching section 20A and the merging section 20B is closed by the flow path switching valve 18, (Refer to the position of the flow path switching valve 18 indicated by the two-dot chain line in Fig. 1 and Fig. 2). The exhaust heat recovery mode is a mode for exchanging heat between the exhaust gas and the cooling water. On the other hand, in a mode other than the exhaust heat recovery mode, the flow path between the branching section 20A and the merging section 20B is opened by the flow path switching valve 18 so that the exhaust gas passes through the flow path in the normal mode (Refer to the position of the flow path switching valve 18 indicated by a solid line in Figs. 1 and 2).

(With respect to the heat transfer inhibiting mechanism 50)

Next, the heat transfer inhibiting mechanism 50, which is a main part of the present invention, will be described. 1, the heat transfer suppressing mechanism 50 is applied to the connection portion between the first pipe 20 and the second pipe 30, and the connection between the first pipe 20 and the second pipe 30 The heat transfer suppressing mechanism 50 suppresses the heat of the first pipe 20 from being transferred to the second pipe 30. [ The heat transfer suppressing mechanism 50 includes a second pipe flange 32 serving as a "second flange" formed in the second pipe 30 and a second pipe flange 32 serving as a second flange for fixing the second pipe 30 to the first pipe 20 A plurality of bolts 52, a weld nut 54 as a "nut", and a heat insulating material 56.

The second pipe flange 32 is formed at the upstream end 30A and the downstream end 30B of the second pipe 30, respectively. Specifically, the second pipe flange 32 is bent at a substantially right angle to the outside of the second pipe 30, and is formed around the entire circumferential direction of the second pipe 30. The second pipe flange 32 formed on the upstream side end portion 30A of the second pipe 30 is connected to the branch pipe 22 in the first pipe 20 on the outer side of the first pipe 20 As shown in Fig. The second piping flange 32 formed on the downstream side end portion 30B of the second piping 30 is located outside the first piping 20 in the confluence hole 24 in the first piping 20 As shown in Fig.

The weld nut 54 is provided at the periphery of the branch hole 22 in the first pipe 20 in the thickness direction of the side wall 20S in the axial direction within the first pipe 20 And are arranged at predetermined intervals in the circumferential direction of the branch hole 22. The weld nut 54 is formed in the first pipe 20 so as to extend in the thickness direction of the side wall 20S in the axial direction and in the peripheral direction of the joining hole 24 in the first pipe 20 And is disposed at a predetermined interval in the circumferential direction of the confluent hole 24. [ An insertion hole 26 is formed in the first pipe 20 at a position corresponding to the weld nut 54. The second pipe flange 32 is also formed with an insertion hole 32A at a position corresponding to the weld nut 54. As shown in Fig.

The heat insulating material 56 is formed of a ceramic fiber or a glass wool and is formed into a frame shape corresponding to the shape of the second pipe flange 32 of the second pipe 30. [ The heat insulating material 56 is disposed between the periphery of the branch hole 22 of the first pipe 20 and the second pipe flange 32 and between the periphery of the joining hole 24 of the first pipe 20 And is disposed between the peripheral portion and the second pipe flange 32, respectively. That is, the second pipe flange 32 is connected to the first pipe 20 via the heat insulating material 56. [ An insertion hole 56A is formed in the heat insulating material 56 at a position corresponding to the weld nut 54. As shown in FIG. The bolt 52 is inserted from the outside of the first pipe 20 into the insertion hole 32A of the second pipe flange 32, into the insertion hole 56A of the heat insulating material 56, 20, and is screwed into the weld nut 54. The welded hole 54 is formed in the through-hole 26, as shown in Fig. As a result, the second pipe flange 32 is fastened to the first pipe 20 via the heat insulating material 56 so that the upstream end 30A and the downstream end 30B of the second pipe 30 1 pipe (20).

Next, the operation and effects of the present embodiment will be described.

When the flow path switching valve 18 closes the flow path between the branching section 20A and the merging section 20B under the control of the ECU in the exhaust gas recirculation apparatus 10 constructed as described above, And flows into the second pipe 30 from the branch hole 22 of the second pipe 30. The heat of the exhaust gas flowing into the second pipe 30 is heat-exchanged with the cooling water in the heat recovery unit 40. Thereby, the heat of the exhaust gas is recovered by the heat recovery device 40.

Since the exhaust gas of the engine 12 flows through the first pipe 20, the first pipe 20 is heated by the exhaust gas. When the heat of the first pipe 20 is directly transferred to the second pipe 30 connected to the first pipe 20, the cooling water in the heat recovery device 40 provided in the second pipe 30 is discharged by the heat The temperature of the cooling water in the heat recovery unit 40 rises. At this time, if the cooling water in the heat recovery unit 40 boils, for example, there is a fear that an abnormal noise due to boiling of the cooling water may occur in the heat recovery unit 40. [

Here, in the arrangement recycling apparatus 10, the heat conduction suppressing mechanism 50 is provided at the connection portion between the first pipe 20 and the second pipe 30. [ The heat transfer suppressing mechanism 50 has a heat insulating material 56 and a heat insulating material 56 is adhered to the second piping flange 32 formed at the upstream side end 30A and the downstream side end 30B of the second piping 30 ) And the first pipe (20). The heat insulating material 56 can prevent the heat of the first pipe 20 from being transferred to the second pipe 30 at the connection portion between the first pipe 20 and the second pipe 30 . As a result, excessive temperature rise of the second pipe 30 due to the heat of the first pipe 20 can be suppressed, and the boiling of the cooling water in the heat recovery device 40 can be suppressed. As a result, it is possible to suppress the occurrence of an abnormal sound of the heat recovery device 40 due to boiling of the cooling water.

Particularly, in the case where the circulation of the cooling water in the cooling water circulation path 16 is stopped (at the time of stopping the engine 12 or during the intermittent operation of the engine 12 in the hybrid car, etc.) do. Therefore, in this case, the temperature of the cooling water in the heat recovery unit 40 tends to rise due to the heat transmitted from the first pipe 20 to the second pipe 30. On the contrary, in the exhaust heat recovery apparatus 10 according to the present embodiment, the heat insulating material 56 of the heat transfer suppressing mechanism 50 is provided at the connection portion between the first pipe 20 and the second pipe 30 Therefore, the heat of the first pipe 20 can be prevented from being transferred to the second pipe 30, and the excessive temperature rise of the cooling water retained in the heat recoverer 40 can be suppressed. Therefore, it is possible to effectively suppress the boiling of the cooling water in the heat recovery device 40 when the circulation of the cooling water is stopped.

As described above, in the heat transfer inhibiting mechanism 50, the heat insulating material 56 is interposed between the second pipe flange 32 of the second pipe 30 and the first pipe 20, And the connection of the second pipe 30 is suppressed. Therefore, it is possible to suppress the boiling of the cooling water in the heat recovery device 40 to a simple configuration.

The second piping 30 is arranged in parallel with the first piping 20 and the heat recovery device 40 is installed inside the second piping 30. The heat recovery device 40 is installed in the second piping 30, That is, the array collecting apparatus 10 has a so-called parallel structure in which the heat collectors 40 are disposed in parallel to the first pipe 20. The first piping 20 to the heat collecting device 40 can be more reliably used as compared with the arrangement collecting device having a coaxial structure in which the second piping and the heat collecting device are arranged in an annular shape on the outer side of the first piping 20, It is possible to lower the influence of the radiant heat of Thereby, the arrangement recovery apparatus 10 can be arranged in an effective arrangement with respect to suppressing the boiling of the cooling water in the heat recovery apparatus 40.

The heat recovery suppression mechanism 50 of the exhaust heat recovery apparatus 10 is configured such that the upstream end 30A of the second pipe 30 and the connection portion of the first pipe 20 and the downstream end of the second pipe 30 (30B) and the first pipe (20). The heat transfer suppressing mechanism 50 is connected to the connecting portion between the upstream end 30A of the second pipe 30 and the first pipe 20 and the downstream end 30B of the second pipe 30, The heat of the first pipe 20 can be prevented from being transferred from the upstream side and the downstream side of the second pipe 30 to the heat collecting device 40 as compared with the case where the first pipe 20 is applied to one of the connecting portions of the second pipe 20. This makes it possible to further suppress the boiling of the cooling water in the heat recovery device (40).

(Modification of the Heat Prevention Mechanism 50 in the First Embodiment)

In the first embodiment described above, the heat transfer suppressing mechanism 50 includes the heat insulating material 56. In this modification, as shown in Fig. 3, in the heat transfer suppressing mechanism 50, the heat insulating material 56, Is omitted. That is, in this modification, the second pipe flange 32 of the second pipe 30 is fastened and fixed directly to the first pipe 20 by the bolts 52 and the weld nuts 54, 30) is connected to the first pipe (20). In view of suppressing the boiling of the cooling water in the heat recovery device 40, the second piping flange 32 of the second piping 30 is connected to the second piping 30 via the heat insulating material 56 as in the first embodiment. It is preferable to connect the first heat exchanger 20 and the first heat exchanger 20 to the first heat exchanger 20 but it is possible to contribute to suppressing the boiling of the cooling water in the heat recoverer 40 even when the heat insulating material 56 is omitted in the heat transfer suppressing mechanism 50 . This point will be described below.

When the second pipe flange 32 of the second pipe 30 is directly fastened and fixed to the first pipe 20 by the bolts 52 and the weld nuts 54 as shown in this modification, The fastening portion of the second pipe 32 with the first pipe 20 is locally closely attached to the first pipe 20. That is, although the adhesion between the second pipe flange 32 and the first pipe 20 is enhanced, the adhesion of the second pipe flange 32 and the portion of the first pipe 20 where the first pipe 20 is not fastened is relatively low . This is because it is inevitable that the entire surface of the second pipe flange 32 opposed to the first pipe 20 is brought into contact with the outer peripheral surface of the first pipe 20 due to, So that a minute gap is formed between the second pipe flange 32 and the outer peripheral surface of the first pipe 20.

Therefore, in this modification, the heat conduction of the portion where the second piping flange 32 and the first piping 20 are not fastened is comparatively low, and the heat of the first piping 20 mainly flows into the bolts 52 and And acts to be transmitted to the second pipe 30 via the fastening portion fastened by the weld nut 54. Conversely, the heat of the first pipe 20 can be prevented from being transferred to the second pipe 30 at the portion where the second pipe flange 32 and the first pipe 20 are not fastened. As a result, the heat transfer resistance at the connection portion between the first pipe 20 and the second pipe 30 can be made relatively high. As a result, even if the second pipe flange 32 of the second pipe 30 is fastened and fixed directly to the first pipe 20 by the bolts 52 and the weld nuts 54, It is possible to suppress the boiling of the cooling water. Therefore, it is possible to suppress the boiling of the cooling water in the heat recovery device 40 to a more simple configuration.

(Second Embodiment)

Hereinafter, the array recovery apparatus 60 of the second embodiment will be described with reference to FIG. The array recovery apparatus 60 of the second embodiment is configured in the same manner as the array recovery apparatus 10 of the first embodiment except for the heat transfer prevention mechanism 50. [ Hereinafter, the heat transfer prevention mechanism 50 of the array recovery apparatus 60 will be described. In Fig. 4, the same components as those of the first embodiment are designated by the same reference numerals.

The heat insulating material 56, the bolt 52 and the weld nut 54 are omitted in the heat transfer suppressing mechanism 50 of the array recovery apparatus 60 and the second pipe flange 32 of the second pipe 30 is omitted from the laser And is directly bonded to the first pipe 20 by welding. 4 shows the welded portion 58 for the sake of easy understanding of the welding width W1 of the welded portion 58 between the second pipe flange 32 joined by laser welding and the first pipe 20, Is schematically shown as a dot continuously written in the thickness direction of the first pipe 20 and the second pipe flange 32. [ The welded portion 58 is formed around the entire circumference of the second pipe flange 32.

However, in general, in the arrangement recovery apparatus, the second piping is joined to the first piping by arc welding so as to connect them (hereinafter, this apparatus is referred to as an arrangement recovery apparatus of a comparative example). 4, the second piping flange 32 of the second piping 30 is connected to the second piping flange 32 in the comparative example like the welded portion 62 indicated by the two-dot chain line in Fig. Is welded to the first pipe 20 by the welded portion 62 formed by arc welding. In welding by arc welding, the welding width W2 of the welding portion 62 generally tends to be relatively wider (for example, the welding width W2 of the welding portion 62 is about 5 mm or more ). Therefore, in the comparative example, the heat of the first pipe 20 is discharged from the entire circumference of the second pipe flange 32 of the second pipe 30 through the welding portion 62 having a relatively wide welding width, (30).

On the other hand, in the second embodiment, the second pipe flange 32 is joined to the first pipe 20 by the welded portion 58 around the entire circumferential direction of the second pipe flange 32, It is possible to suppress the heat of the first pipe 20 from being transmitted to the second pipe 30, as compared with the example. That is, since the welding portion 58 is formed by laser welding, the welding width W1 of the welding portion 58 can be made smaller than the welding width W2 of the welding portion 62 of the above-described comparative example The welding width W1 of the welded portion 58 can be set to about 1 mm). Therefore, compared with the comparative example, the heat transfer resistance at the connection portion between the first pipe 20 and the second pipe 30 can be increased (the heat transfer property can be lowered). Therefore, in the second embodiment, the heat of the first pipe 20 is less likely to be transmitted to the second pipe 30 as compared with the comparative example. Therefore, also in the second embodiment, the boiling of the cooling water in the heat recovery unit 40 can be suppressed.

(Third Embodiment)

Hereinafter, the arrangement recovery apparatus 70 of the third embodiment will be described with reference to FIG. The array recovery apparatus 70 of the third embodiment is configured in the same manner as the array recovery apparatus 10 of the first embodiment except for the heat transfer prevention mechanism 50. Hereinafter, the heat transfer suppressing mechanism 50 of the array recovery apparatus 70 will be described. In Fig. 5, the same components as those of the configuration of the exhaust system 10 of the first embodiment are denoted by the same reference numerals.

The heat insulating material 56 is omitted in the heat transfer restraining mechanism 50 of the array recovery device 70. [ The heat transfer suppressing mechanism 50 of the exhaust heat recovery apparatus 70 has a first pipe flange 28 as a "first flange" formed in the first pipe 20 and a first pipe flange 28, And is formed on the periphery of the branch hole 22 and the merging hole 24 of the single pipe 20, respectively. The first pipe flange 28 formed at the periphery of the branch hole 22 and the first pipe flange 28 formed at the periphery of the confluent hole 24 are configured identically. Therefore, in the following description, the first pipe flange 28 formed on the periphery of the branch hole 22 will be described, and the description of the first pipe flange 28 formed on the periphery of the merging hole 24 will be omitted .

The first pipe flange 28 is curved at the outer side of the first pipe 20 so as to be folded back from the periphery of the branch hole 22 to the outside of the branch hole 22. [ Specifically, the first pipe flange 28 has a base portion 28A bent from the periphery of the branch hole 22 at a substantially right angle to the outside of the first pipe 20, and a base portion 28B extending from the front end portion of the base portion 28A And a connection flange portion 28B that extends and protrudes outward of the hole 22. [ Further, the first pipe flange 28 is formed around the entire circumferential direction of the branch hole 22. The connection flange portion 28B is disposed substantially parallel to the side wall 20S on which the branch hole 22 is formed and is arranged to face the second pipe flange 32 of the second pipe 30. [

The weld nut 54 is provided on the opposing surface of the connection flange portion 28B facing the outer circumferential surface of the first pipe 20 and at a predetermined interval in the circumferential direction of the connection flange portion 28B Respectively. The insertion hole 26 of the first pipe 20 is formed at a portion corresponding to the weld nut 54 in the connection flange portion 28B. The bolt 52 is inserted into the insertion hole 32A of the second pipe flange 32 and into the insertion hole 26 of the connection flange portion 28B and screwed to the weld nut 54 have. The second pipe flange 32 is fastened to the connection flange portion 28B and the first pipe 20 is connected to the second pipe 30. [

As described above, in the third embodiment, the first pipe flange 28 is formed at the periphery of the branch hole 22 and the merging hole 24 of the first pipe 20, and the first pipe flange 28 Is bent outwardly from the peripheral edge of the branch hole 22 to the outside of the branch hole 22 on the outer side of the first pipe 20. The second pipe flange 32 of the second pipe 30 is fastened and fixed to the connection flange portion 28B of the first pipe flange 28 by bolts 52 and weld nuts 54. [ 3, the second pipe flange 32 is directly fastened to the periphery of the branch hole 22 and the merging hole 24 of the first pipe 20, The transmission path of the heat from the first pipe 20 to the second pipe 30 can be made as long as the first pipe flange 28. [ This makes it possible to suppress the heat of the first pipe 20 from being transmitted to the second pipe 30 at the connection portion of the first pipe 20 and the second pipe 30, 40 can be effectively suppressed.

In the third embodiment, the second pipe flange 32 is directly connected to the connection flange portion 28B of the first pipe flange 28. [ A heat insulating material 56 may be interposed between the second pipe flange 32 and the connecting flange portion 28B in the same manner as in the first embodiment. This makes it possible to further effectively prevent the heat of the first pipe 20 from being transmitted to the second pipe 30 at the connection portion between the first pipe 20 and the second pipe 30, It is possible to more effectively suppress the boiling of the cooling water in the reclaimer 40.

In the first to third embodiments, the heat retention mechanism 50 is applied to the array recovery apparatuses 10, 60, and 70 having a parallel structure. However, as shown in FIG. 6, the first piping 20 The heat transfer suppressing mechanism 50 may be applied to the arrangement recovery device 80 in which the annular second piping 30 and the heat recovery device 40 are disposed.

The array recovery apparatus 80 will be briefly described. In the array recovery apparatus 80, only the branch hole 22 is formed in the first pipe 20. In addition, the second pipe 30 forms an annular shape and is arranged outside the first pipe 20. The second pipe 30 is formed in a substantially U-shape opening to the first pipe 20 side in a sectional view viewed from the circumferential direction thereof. A second pipe flange 32 is formed at the opening end of the second pipe 30. A pipe-shaped inner pipe 82 is disposed inside the second pipe 30 and the inner pipe 82 is connected to the first pipe 20 at a position not shown. In addition, a heat recovery device 40 is formed in an annular shape and disposed radially outward of the inner pipe 82. The heat recovery suppression mechanism 50 of the first embodiment is applied to the connection portion between the second piping flange 32 and the first piping 20 in the arrangement recovery apparatus 80. That is, a heat insulating material 56 is interposed between the second pipe flange 32 and the first pipe 20 so that the second pipe 30 is connected to the first pipe (not shown) by the bolt 52 and the weld nut 54 20). Therefore, even in the exhaust heat recovery device 80, excessive temperature rise of the second pipe 30 can be suppressed, and the boiling of the cooling water in the heat recovery device 40 can be suppressed. Although not shown in FIG. 6, the flow path switching valve 18 is provided in the first pipe 20 in the same manner as the arrangement recovery device 10 or the like.

In the first and third embodiments, the weld nut 54 is provided in the first pipe 20, and the bolt 52 is screwed to the weld nut 54, Is fastened to the first pipe (20). A bolt as a stud bolt protruding outside the first pipe 20 is provided in the first pipe 20 and the nut is screwed to the bolt so that the second pipe 30 is connected to the first pipe 20. [ May be fastened to the first pipe (20).

In the first to third embodiments, the heat transfer suppressing mechanism 50 is provided between the upstream end 30A of the second pipe 30 and the connecting portion of the first pipe 20, And is applied to the connection portion between the downstream side end portion 30B and the first pipe 20, respectively. The heat transfer suppressing mechanism 50 may be connected to the upstream end 30A of the second pipe 30 and the connecting portion of the first pipe 20 and the downstream end 30B of the second pipe 30, Or may be applied to one of the connecting portions of the pipe 20.

(Fourth Embodiment)

Hereinafter, the arrangement recovery apparatus 90 of the fourth embodiment will be described with reference to FIG. The arrangement recollecting apparatus 90 of the fourth embodiment is configured in the same manner as the arrangement recollecting apparatus 10 of the first embodiment except for the second piping 30 and the heat retaining mechanism 50. [ Hereinafter, the branch piping 34 and the heat transfer suppressing mechanism 50 as the second piping of the array recovery apparatus 90 will be described. In Fig. 7, the same components as those of the first embodiment are designated by the same reference numerals.

7, the batch recovery apparatus 90 includes a first piping 20, a branch piping 34 integrally branched from the first piping 20, and a branch piping 34, And a heat recovery device 42 mounted to the opening so as to close the opening of the heat recovery device. The heat recovery device 42 has a flow path 44 through which the cooling water passes to the outer peripheral portion of the heat recovery device main body 43 and the cooling water circulation path 16 is connected to the flow path 44.

A tray-shaped header plate 46 constituting the heat transfer suppressing mechanism 50 is mounted on the downstream side in the mounting direction (indicated by arrow C) of the heat recovery device 42 to the opening of the branch pipe 34 . That is, the heat recovery device 42 is mounted in the opening of the branch pipe 34 from the header plate 46 side to close the opening. The opening end 34A side of the branch pipe 34 is widened so that the heat collecting unit 42 (header plate 46) can be mounted on the inner side (the bent portion 36 is formed).

The header plate 46 is provided with an upstream opening (not shown) through which exhaust gas can flow and a downstream opening (not shown) through which the exhaust gas can flow. The downstream side opening of the header plate 46 is openable and closable by the flow path switching valve 18 provided in the first pipe 20.

That is, the flow path switching valve 18 is disposed at a position corresponding to the center portion (the central axis portion of the branch pipe 34) of the header plate 46. As indicated by the two-dot chain line in Fig. 7, When the opening on the downstream side of the plate 46 is closed, the normal mode is established, and the exhaust gas is allowed to pass through the first pipe 20.

On the other hand, when the flow path switching valve 18 closes the flow path of the first pipe 20 at the central portion of the header plate 46 (the axial center portion of the branch pipe 34), the exhaust heat recovery mode is set, Flows from the first pipe 20 through the branch pipe 34 into the heat collecting device main body 43 through the upstream opening of the header plate 46.

The exhaust gas flowing into the heat recovery device main body 43 from the upstream side opening of the header plate 46 is heat-exchanged with the cooling water flowing in the heat recovery device main body 43 and the heat- And flows out from the downstream side opening. The exhaust gas flowing out from the opening on the downstream side of the header plate 46 is returned to the first pipe 20 through the branch pipe 34.

The heat transfer suppressing mechanism 50 in the arrangement recycling apparatus 90 having the above-described structure is provided at the connection portion between the branch pipe 34 and the heat collecting device 42 and is connected to the heat recovery device 42 to prevent the heat from being transmitted to the outside. A flange portion 48 extending toward the upstream side in the mounting direction of the branch pipe 34 of the heat recovery device 42 is integrally formed over the entire periphery of the header plate 46 .

The flange portion 48 is configured to contact the outer wall surface 45 of the heat sink main body 43 constituting the flow path 44 from the outside and to cover a part of the outer wall surface 45 . The front end portion 48A of the flange portion 48 of the header plate 46 and the branch pipe 34 disposed flush with the front end portion 48A of the header pipe 46 And the opening end portions 34A are all joined by arc welding (hereinafter, the welded portions are referred to as " welded portions 64 ").

The distance L from the bent portion 36 of the branch pipe 34 disposed upstream of the header plate 46 to the welded portion 64 can be set to be long and the distance from the welded portion 64 to the heat- The heat transfer path R to the cooling water (the end portion 43A on the header plate 46 side of the heat recovery device main body 43) in the flow path 44 of the heat recovery device 42 can be set long. As a result, it is possible to suppress excessive temperature rise of the cooling water in the heat recovery unit 42 due to the heat of the branch pipe 34, and the boiling of the cooling water can be suppressed.

Particularly, since the flange portion 48 of the header plate 46 extends toward the upstream side in the mounting direction of the branch pipe 34 of the heat collecting device 42, the flange portion 48 is connected to the heat- The heat transfer path R from the welded portion 64 to the cooling water in the heat recovery device 42 is set longer than the configuration in which the heat transfer path R does not extend toward the upstream side in the mounting direction of the branch pipe 34 of the heat recovery device 42 And it is possible to effectively suppress the boiling of the cooling water in the heat recovery device 42. [

Since the welded portion 64 is provided on the outer wall surface 45 of the heat sink main body 43 constituting the flow path 44 through which the cooling water passes, . ≪ / RTI > Therefore, it is possible to suppress a decrease in bonding strength in the welded portion 64. [

Further, the heat conduction limiting mechanism 50 (the flange portion 48 of the header plate 46) in the fourth embodiment is not limited to the structure that is welded by arc welding. For example, like the second embodiment, it may be configured to be joined by laser welding. The tip end portion 48A of the flange portion 48 and the opening end portion 34A of the branch pipe 34 in the header plate 46 may be arranged in a plane or may extend longer than the position shown in the drawing do.

Claims (10)

A first pipe through which exhaust gas from the engine flows,
A second pipe communicating with the first pipe and bypassing the first pipe,
A heat recovery unit disposed in the second pipe and recovering the heat of the exhaust gas by heat exchange between the cooling water circulating inside and the exhaust gas;
And an electric conduction suppressing mechanism provided at a connection portion between the first pipe and the second pipe to suppress transmission of heat from the first pipe to the second pipe. The method according to claim 1,
Wherein the heat transfer suppressing mechanism has a heat insulating material,
And the second pipe is connected to the first pipe via the heat insulating material. 3. The method according to claim 1 or 2,
A communication hole communicating the inside of the first pipe and the inside of the second pipe is formed in the connection portion of the first pipe with the second pipe,
The heat transfer suppressing mechanism includes:
A first flange formed on the periphery of the communication hole of the first pipe and folded back to the outside of the communication hole outside the first pipe;
And a second flange formed at a connection portion of the second pipe with the first pipe and connected to the first flange. 4. The method according to any one of claims 1 to 3,
Wherein the heat transfer suppressing mechanism includes a bolt and a nut,
And the first pipe and the second pipe are connected by being fastened by the bolt and the nut. 5. The method according to any one of claims 1 to 4,
And the upstream end and the downstream end of the second pipe are connected to the first pipe. 6. The method of claim 5,
Wherein the heat transfer suppressing mechanism is provided at a connecting portion between the upstream end portion and the connecting portion of the first pipe and the connecting portion between the downstream end portion and the first pipe. A first pipe through which exhaust gas from the engine flows,
A second pipe branched from the first pipe,
And a heat recovering device for recovering the heat of the exhaust gas by heat exchange between the cooling water circulating inside the exhaust pipe and the exhaust gas, Wow,
And a heat conduction suppressing mechanism provided at a connection portion between the second pipe and the heat recovery device for suppressing the transmission of heat from the second pipe to the heat recovery device,
Wherein the heat recovery device has a flow passage through which cooling water passes through the outer peripheral portion,
Wherein the heat transfer suppressing mechanism includes an outer peripheral portion of the header plate welded together with an opening end of the second pipe to an outer wall surface constituting the flow path. 8. The method of claim 7,
And an outer peripheral portion of the header plate extends toward an upstream side in a mounting direction of the heat recovery device to the opening of the second pipe. The method according to claim 1,
And the connecting portion of the first pipe and the second pipe is joined by laser welding. 10. The method of claim 9,
Wherein a connection portion between the first pipe and the second pipe is formed around the entire circumferential direction of the second pipe.

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