JP2008157091A - Exhaust heat recovery system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust heat recovery system for an internal combustion engine switching the state of passage of exhaust to surely restrict heat exchange, while promoting exchange of heat between cooling water and the exhaust of the internal combustion engine. <P>SOLUTION: The exhaust heat recovery system 1A has a heat recovery part 3 disposed in an outer periphery of an exhaust passage part 2 through which the exhaust of the internal combustion engine to flow the cooling water therein. Since an inner pipe 4 is disposed inside the exhaust passage part 2, the exhaust passage part 2 is divided into an inside passage 5 and the outside passage positioned outside the inner passage 5. A slide valve 7 is provided to switch the passage state of the exhaust passing through the exhaust passage part 2, between a heat exchange promotion state prohibiting the passage of the exhaust in the inside passage 5 and allowing the passage of exhaust in the outside passage 6, and an heat exchange restriction state allowing the passage of the exhaust in the inside passage 5 and prohibiting the passage of the exhaust in the outside passage 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust heat recovery apparatus for an internal combustion engine that exchanges heat between exhaust gas guided to an exhaust passage of the internal combustion engine and cooling water of the internal combustion engine.

  As an exhaust heat recovery device that recovers the heat of exhaust gas from an internal combustion engine, an exhaust passage portion through which the exhaust of the internal combustion engine passes is divided into a heat transfer passage adjacent to the refrigerant pipe that guides the refrigerant and a bypass passage that bypasses the refrigerant pipe And what switches the passage state of exhaust gas by opening and closing the on-off valve provided in the bypass passage is known (patent document 1). In addition, there is Patent Document 2 as a prior art document related to the present invention. In the device of Patent Document 1, all of the exhaust gas flowing into the exhaust passage when the bypass passage is closed by the on-off valve is guided to the heat transfer passage and is discharged from the outlet. On the other hand, when the bypass passage is opened by the on-off valve, a part of the exhaust gas flowing into the exhaust passage portion is discharged to the outlet through the bypass passage, so that the amount of heat transfer from the exhaust to the refrigerant is reduced.

Japanese Patent Laid-Open No. 9-76739 JP-A-2-104952

  However, in the apparatus of Patent Document 1, even if the bypass passage is opened in order to reduce the amount of heat transfer from the exhaust to the refrigerant, the heat transfer passage remains open without being closed. Go through the passage. For this reason, even when heat exchange should be restricted, heat transfer from the exhaust to the refrigerant occurs, and the temperature of the refrigerant may rise unexpectedly.

  Therefore, the present invention provides an exhaust heat recovery device for an internal combustion engine that can promote the heat exchange between the cooling water and the exhaust gas of the internal combustion engine and can switch the passage state of the exhaust gas so that the heat exchange can be surely limited. The purpose is to do.

  In the exhaust heat recovery apparatus for an internal combustion engine according to the present invention, a heat recovery portion through which cooling water of the internal combustion engine flows is arranged on an outer periphery of an exhaust passage portion through which the exhaust of the internal combustion engine passes, and the exhaust gas passing through the exhaust passage portion In an exhaust heat recovery apparatus for an internal combustion engine that performs heat exchange with cooling water flowing through the heat recovery section, the exhaust passage section is divided into an inner passage and an outer passage located outside the inner passage. A partition wall extending in a direction from the inlet to the outlet of the exhaust passage, a heat exchange promotion state that prohibits passage of exhaust in the inner passage and allows passage of exhaust in the outer passage, and exhaust in the inner passage Switching means for switching a passage state of the exhaust gas passing through the exhaust passage portion between a heat exchange restricted state that allows passage of the exhaust gas and prohibits passage of the exhaust gas in the outer passage, To solve the problems mentioned (claim 1).

  According to the exhaust heat recovery apparatus of the present invention, when the heat exchange is in an accelerated state, the exhaust passage in the inner passage is prohibited and the exhaust flowing through the exhaust passage portion passes through the outer passage, so that the heat exchange in the heat recovery portion is wasted. Can be done without. On the other hand, in the heat exchange restricted state, the passage of exhaust gas in the outer passage is prohibited, and the exhaust gas flowing through the exhaust passage portion passes through the inner passage, so that heat exchange in the heat recovery portion can be reliably restricted. Thereby, when it switches to the heat exchange acceleration | stimulation state, a cooling water can be heated up rapidly. On the other hand, when switched to the heat exchange restricted state, heat exchange can be reliably restricted, so that overheating can be prevented.

  In the exhaust heat recovery apparatus of the present invention, there is no particular limitation on the configuration of the switching means as long as the exhaust passage in the outer passage can be prohibited in the heat exchange restricted state. For example, in one aspect of the exhaust heat recovery apparatus of the present invention, the switching means is located on the inlet side of the exhaust passage portion and is provided on the inlet side valve body that can open and close the outer passage, and on the outlet side of the exhaust passage portion. An outlet-side valve element that can be positioned to open and close the inner passage, and the inlet-side valve element opens the outer passage and the outlet-side valve element closes the inner passage when the heat exchange is promoted. The inlet-side valve body and the outlet-side valve body can be moved integrally so that the inlet-side valve body closes the outer passage and the outlet-side valve body opens the inner passage when in a heat exchange restricted state. And a connecting means for connecting (Claim 2). According to this aspect, by integrally moving the inlet side valve body and the outlet side valve body connected by the connecting means, the opening of the outer passage and the closing of the inner passage can be realized simultaneously, and the closing of the outer passage The opening of the inner passage can be realized at the same time.

  In this aspect, the connecting means may connect the inlet side valve body and the outlet side valve body with an elastically deformable elastic member interposed therebetween (claim 3). In this case, when the force with which the outlet side valve body is pushed by the exhaust gas in the heat exchange promotion state is increased, the elastic member is elastically deformed to open the inner passage so that the exhaust gas can be released. Therefore, by appropriately setting the elastic coefficient of the elastic member, it is possible to prevent an increase in back pressure exceeding an allowable value in the heat exchange acceleration state.

  In one aspect of the exhaust heat recovery apparatus of the present invention, the switching means closes an outlet of the exhaust passage portion at one end when the heat exchange is promoted and passes the exhaust when the heat exchange is restricted. A cylindrical body provided in a slidable state along the partition wall so as to close the inlet of the part at the other end, and provided at the other end of the cylindrical body in the heat exchange promotion state. An opening / closing valve that closes the other end and opens the other end when the heat exchange is in a restricted state, and the peripheral wall of the cylindrical body has the opening when the heat exchange is promoted. A passage hole may be provided that is opened at the partition wall and closed at the partition wall when the heat exchange is restricted (claim 4). According to this aspect, by opening and closing the on-off valve according to the position of the cylindrical body while sliding the cylindrical body, the opening of the outer passage and the closing of the inner passage can be realized simultaneously, and the closing of the outer passage and The opening of the inner passage can be realized at the same time.

  Further, in one aspect of the exhaust heat recovery apparatus of the present invention, the switching unit is capable of relative rotation so that a relative position changes between the heat exchange promotion state and the heat exchange restriction state. And is configured as a rotary valve provided on the inlet side of the exhaust passage portion, and each plate of the rotary valve is provided at a position corresponding to the inner passage. An inner passage hole and an outer passage hole provided at a position corresponding to the outer passage, and the rotary valve is configured such that the inner passage hole of one plate-like body is the other when the heat exchange is promoted. And the outer passage holes of the respective plate-like bodies overlap with each other, and the inner passage holes of the respective plate-like bodies overlap with each other in the heat exchange restricted state, and one plate-like body. The outer passage hole is closed by the other plate-like body As may be set each of the size and position of said inner passage hole and the outer passage hole formed in each plate-like body (Claim 5). According to this aspect, by rotating and moving at least one plate-like body of the rotary valve, the opening of the outer passage and the closing of the inner passage can be realized simultaneously, and the closing of the outer passage and the opening of the inner passage are simultaneously performed. realizable. Since the rotary valve of this aspect does not move in the direction in which the partition wall extends in order to switch the exhaust passage state, it is not necessary to secure an extra space for movement in addition to the space for mounting the rotary valve. Therefore, there exists an advantage which can suppress the increase in the dimension to the direction where a partition wall is extended.

  As described above, according to the present invention, when the heat exchange is promoted, the passage of the exhaust gas in the inner passage is prohibited, and the exhaust gas flowing through the exhaust passage portion passes through the outer passage. It can be done without waste. On the other hand, in the heat exchange restricted state, the passage of exhaust gas in the outer passage is prohibited and the exhaust gas flowing through the exhaust passage portion passes through the inner passage, so that heat exchange in the heat recovery portion can be reliably restricted. Thereby, when switched to the heat exchange promotion state, the temperature of the cooling water can be quickly raised, and when switched to the heat exchange restricted state, the heat exchange can be reliably restricted.

(First form)
1 shows an embodiment of the exhaust heat recovery apparatus of the present invention, FIG. 2 shows a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 shows a cross-sectional view taken along line III-III in FIG. Show. The exhaust heat recovery device 1A is attached to an exhaust passage 101 of an internal combustion engine (not shown), and is disposed on the exhaust passage portion 2 through which exhaust gas guided to the exhaust passage 101 passes, and on the outer periphery of the exhaust passage portion 2 to cool the internal combustion engine. And a heat recovery unit 3 through which water flows. In the exhaust heat recovery device 1A, heat exchange is performed between the exhaust gas that has passed through the exhaust passage section 2 and the cooling water flowing through the heat recovery section 3, and the cooling water after the heat exchange is guided to each part of the internal combustion engine through the cooling water channel 102. It is burned.

  An inner pipe 4 as a partition wall is provided inside the exhaust passage portion 2 so as to extend in a direction from the inlet 2 a to the outlet 2 b of the exhaust passage portion 2, and the exhaust passage portion 2 is connected to the inner passage 5 by the inner tube 4. It is divided into an outer passage 6 positioned outside the inner passage 5. In the illustrated form, the outer passage 6 is disposed so as to surround the inner passage 5 (see FIGS. 2 and 3).

  The exhaust passage 2 is provided with a slide valve 7 as switching means for switching the exhaust passage state. FIG. 4 is an enlarged perspective view of the slide valve 7. As shown in FIGS. 1 to 4, the slide valve 7 is located on the inlet 2 a side of the exhaust passage portion 2 and can be opened and closed on the outer passage 6, and on the outlet 2 b side of the exhaust passage portion 2. And an outlet side valve body 9 capable of opening and closing the inner passage 5, and a connecting member 10 as a connecting means for connecting the inlet side valve body 8 and the outlet side valve body 9 so as to be integrally movable. The inlet side valve body 8 has a shape and a size capable of closing the outer passage 6, and the outlet side valve body 9 has a shape and a size capable of closing the inner passage 5. The connecting member 10 connects the valve bodies 8 and 9 such that the distance between the inlet side valve body 8 and the outlet side valve body 9 is larger than the longitudinal dimension of the inner tube 4. Thereby, the slide valve 7 is configured to be slidable along the inner tube 4.

  As shown in FIG. 1, the slide valve 7 is driven by a drive mechanism 10. Although the detailed structure of the drive mechanism 10 is not shown, the drive mechanism 10 includes an actuator 11 as a drive source and a transmission mechanism 12 that transmits the power of the actuator to the slide valve 7. FIG. 5 shows a state in which the slide valve 7 has moved from the state of FIG. 1 to the right in the drawing. As shown in FIGS. 1 and 5, the slide valve 7 is slid by the drive mechanism 10 to prohibit passage of exhaust gas to the inner passage 5 and allow passage of exhaust gas to the outer passage 6. The exhaust passage state is switched between the heat exchange promotion state shown in FIG. 5 and the heat exchange restricted state shown in FIG. 5 that allows passage of exhaust gas to the inner passage 5 and prohibits passage of exhaust gas to the outer passage 6. be able to.

  That is, when the heat exchange promotion state shown in FIG. 1 is established, the outer side passage 6 is opened when the inlet side valve body 8 is separated from one end of the inner pipe 4, and at the same time, the outlet side valve body 9 is The inner passage 5 is closed by contacting the end. Therefore, as indicated by the broken-line arrows in FIG. 1, the exhaust gas guided to the exhaust passage 101 passes through the inlet 2 a of the exhaust passage portion 2 and then passes through the central portion of the inlet side valve body 8 and the outer passage 6 to the outlet. It is discharged from 2b. Thereby, since heat exchange in the heat recovery unit 3 adjacent to the outer passage 6 is promoted, the temperature of the cooling water can be quickly raised.

  On the other hand, in the heat exchange restricted state shown in FIG. 5, the outer side passage 6 is closed by the inlet side valve body 8 coming into contact with one end of the inner pipe 4, and at the same time, the outlet side valve body 9 is moved to the other end of the inner pipe 4. The inner passage 5 is opened by moving away from the end. Therefore, as indicated by the broken-line arrows in FIG. 5, the exhaust gas guided to the exhaust passage 101 passes through the central portion of the inlet side valve element 8 and the inner passage 5 after passing through the inlet 2 a of the exhaust passage portion 2, and exits. It goes around the outside of the side valve body 9 and is discharged from the outlet 2b. Thereby, since the passage of the exhaust gas to the outer passage 6 is prohibited, heat exchange in the heat recovery unit 3 is limited. Therefore, the temperature rise of the cooling water is suppressed and overheating can be prevented.

  Switching between the heat exchange promotion state and the heat exchange restriction state of the exhaust heat recovery apparatus 1A is performed based on the cooling water temperature of the internal combustion engine. FIG. 6 is a flowchart showing an example of a control routine for switching control executed by the control device 13. As shown in this figure, first, the control device 13 acquires the cooling water temperature Tw of the internal combustion engine in step S1. The cooling water temperature Tw is acquired based on an output signal of a water temperature sensor (not shown) provided in the cooling water channel 102. Next, in step S2, it is determined whether or not the cooling water temperature Tw is smaller than a threshold value X that is a lower limit value of a water temperature range in which it is not necessary to collect exhaust heat. When the cooling water temperature Tw is smaller than the threshold value X, it is necessary to recover the exhaust heat, so the process proceeds to step S3 and the drive mechanism 10 is controlled so that the heat exchange is promoted. Thereby, the slide valve 7 is switched to the state of FIG. 1, and heat exchange in the heat recovery unit 3 is promoted. On the other hand, when the cooling water temperature Tw is equal to or greater than the threshold value X, it is not necessary to recover the exhaust heat, so the process proceeds to step S4 and the drive mechanism 10 is controlled so as to enter the heat exchange restricted state. As a result, the slide valve 7 is switched to the state shown in FIG. 5, and heat exchange in the heat recovery unit 3 is limited to prevent overheating.

(Second form)
Next, a second embodiment of the present invention will be described with reference to FIGS. Since this form is the same as the first form except for the form of the switching means, the same components as those in the first form are denoted by the same reference numerals in the drawings, and description thereof is omitted. As shown in these drawings, the exhaust heat recovery apparatus 1B has a cylindrical slide valve 21 as switching means. The cylindrical slide valve 21 is one of a cylindrical body 22 as a cylindrical body fitted inside the inner tube 4 in a slidable state and a cylindrical body 22 positioned on the inlet 2a side of the exhaust passage portion 2 (left side in the figure). And an opening / closing valve 23 rotatably attached to the end of the head (see FIG. 8). The cylindrical body 22 has an outer diameter that can block each of the inlet 2 a and the outlet 2 b of the exhaust passage portion 2 and that does not create a gap with the inner peripheral surface of the inner tube 4. A plurality of passage holes 22 a penetrating the peripheral wall are formed at the other end (right side of the figure) of the cylindrical body 22. The on-off valve 23 is rotationally driven via a conversion mechanism (not shown) that converts linear motion of the cylindrical body 22 into rotational motion around the valve shaft.

  FIG. 9 shows a state where the cylindrical slide valve 21 has moved from the state of FIG. 7 to the left in the drawing. As shown in FIGS. 7 and 9, the cylindrical slide valve 22 is slid by the driving mechanism 10, and the passage hole 22 a is opened and closed by the inner tube 4 along with the sliding, and the open / close valve 23 is the cylindrical body. It is opened and closed by the conversion mechanism according to the position of 22. This prohibits the passage of exhaust gas to the inner passage 5, and allows the passage of exhaust gas to the outer passage 6, and permits the passage of exhaust gas to the inner passage 5, as shown in FIG. The exhaust passage state can be switched between the heat exchange restricted state shown in FIG. 9 and prohibiting passage of the exhaust gas to the outer passage 6. That is, in the heat exchange acceleration state shown in FIG. 7, one end portion of the cylindrical body 22 is separated from the inlet 2a of the exhaust passage portion 2, and a passage hole 22a formed in the other end portion is opened in the inner tube 4. When the opening / closing valve 23 is fully closed, the outer passage 6 is opened and the inner passage 5 is closed simultaneously. Therefore, as indicated by the dashed arrow in FIG. 7, the exhaust gas guided to the exhaust passage 101 passes through the outer passage 6 after passing through the inlet 2 a of the exhaust passage portion 2, and passes through the passage hole 22 a of the cylindrical body 22. It is guided to the inside of the cylindrical body 22 and discharged from the outlet 2b. Thereby, since heat exchange in the heat recovery unit 3 adjacent to the outer passage 6 is promoted, the temperature of the cooling water can be quickly raised.

  On the other hand, in the heat exchange restriction state shown in FIG. 9, the inlet 2 a of the exhaust passage portion 2 is closed at one end of the cylindrical body 22, and the passage hole 22 a formed at the other end is formed in the inner tube 4. When the on-off valve 23 is fully opened, the outer passage 6 is closed and the inner passage 5 is opened at the same time. Therefore, as indicated by the broken-line arrows in FIG. 9, the exhaust gas guided to the exhaust passage 101 is guided to the inside of the cylindrical body 22 located at the inlet 2 a of the exhaust passage portion 2 and passes through the inner passage 5 to the outlet. It is discharged from 2b. Thereby, since the passage of the exhaust gas to the outer passage 6 is prohibited, heat exchange in the heat recovery unit 3 is limited. Therefore, since the temperature rise of the cooling water can be suppressed, overheating can be prevented.

(Third form)
Next, a third embodiment of the present invention will be described with reference to FIGS. Since this form is the same as the first form except for the form of the switching means, the same components as those in the first form are denoted by the same reference numerals in the drawings, and description thereof is omitted. 10 is an exhaust heat recovery apparatus in a heat exchange accelerated state, FIG. 13 is an enlarged cross-sectional view along the line XIII-XIII in FIG. 10, FIG. 14 is an exhaust heat recovery apparatus in a heat exchange restricted state, and FIG. 14 are enlarged cross-sectional views taken along line XV-XV. The exhaust heat recovery apparatus 1C has a rotary valve 31 as switching means. The rotary valve 31 includes a pair of discs (plate bodies) 32 and 33 that are combined in a relatively rotatable state. 11 and 12 are plan views of the discs 32 and 33. FIG. As shown in FIGS. 10 to 12, the disks 32 and 33 have the same diameter and are arranged on the inlet 2 a side of the exhaust passage portion 2 in a state of being in close contact with each other. One disk 33 is fixed in a state of being abutted against the end of the inner tube 4, and the other disk 32 is in a state in which the center C 1 and the center C 2 of the one disk 33 coincide with each other. Is driven to rotate.

  As shown in FIG. 11, the disk 32 is formed with eight outer passage holes 32 a aligned in the circumferential direction at positions corresponding to the outer passage 6, and four inner passages at positions corresponding to the inner passage 5. The holes 32b are formed so as to be aligned in the circumferential direction. On the other hand, as shown in FIG. 12, an outer passage hole 33a and an inner passage hole 33b are also formed in the disc 33, but the arrangement of the inner passage hole 33b with respect to the outer passage hole 33a in the disc 33 is as shown in FIG. The disc 32 is shifted by 45 ° with respect to its arrangement. 11 and 12, when the discs 32 and 33 are overlapped, the outer passage hole 32a of the disc 32 and the outer passage hole 33a of the disc 33 overlap, and at the same time, the inner side of the disc 33. When the through holes 33b are closed by the disk 32 and the disks 32 and 33 are stacked with the disk 32 of FIG. The size of each of the passage holes 32 a, 33 a, 32 b, and 33 b is such that the outer passage hole 33 a of the disk 33 is closed by the disk 32 at the same time as the passage hole 32 b and the inner passage hole 33 b of the disk 33 overlap. And position are set respectively (see FIGS. 13 and 15).

  Accordingly, in the heat exchange acceleration state shown in FIGS. 10 and 13, the inner passage 5 is closed and the outer passage 6 is opened at the same time. Therefore, as shown by the dashed arrow in FIG. The exhaust gas guided to 101 passes through the inlet 2a of the exhaust passage portion 2, and then is guided to the outer passage 6 through the mutually overlapping outer passage holes 32a and 33a, and is discharged from the outlet 2b. Thereby, since heat exchange in the heat recovery unit 3 adjacent to the outer passage 6 is promoted, the temperature of the cooling water can be quickly raised. On the other hand, in the heat exchange restriction state shown in FIGS. 14 and 15, the inner passage 5 is opened and the outer passage 6 is closed at the same time, so that the exhaust passage 101 is shown as indicated by the dashed arrow in FIG. 10. Exhaust gas led to the exhaust passage 2 passes through the inlet 2a of the exhaust passage 2 and is then led to the inner passage 5 through the inner passage holes 32b and 33b overlapping each other, and is discharged from the outlet 2b. Thereby, since the passage of the exhaust gas to the outer passage 6 is prohibited, heat exchange in the heat recovery unit 3 is limited, and overheating can be prevented.

  The present invention is not limited to the above embodiments, and can be implemented in various forms within the scope of the gist of the present invention. The slide valve 7 of the first embodiment shown in FIG. 1 connects the inlet side valve body 8 and the outlet side valve body 9 with the connecting member 10, but elastically deforms to the connecting member 10 as shown in FIG. 16. A connecting means according to the present invention may be configured by attaching an elastic member 41 such as a possible coil spring and connecting the inlet side valve body 8 and the outlet side valve body 9. Thereby, since the elastic member 41 is interposed between the inlet side valve body 8 and the outlet side valve body 9, the force with which the outlet side valve body 9 is pushed by the exhaust in the heat exchange promotion state shown in FIG. 1 is increased. In this case, the elastic member 41 is elastically deformed and the outlet side valve body 9 is separated from the end portion of the inner tube 4 so that the exhaust can be released. In the form of FIG. 16, by appropriately setting the elastic coefficient of the elastic member 41, it is possible to prevent an increase in back pressure exceeding an allowable value in the heat exchange accelerated state. In addition, a seal member that improves the sealing performance such as a seal ring may be attached to the outer periphery of the inlet side valve body 8.

  In the second embodiment shown in FIG. 7, the cylindrical body 22 is fitted inside the inner tube 4, but on the contrary, the cylindrical body 22 may be fitted outside the inner tube 4. . Further, in the third embodiment shown in FIG. 10, the disk 32 on the inlet side is rotated to fix the disk 33 on the outlet side. On the contrary, the disk 32 on the inlet side is fixed. The disk 33 on the outlet side may be rotated. Further, each of the disks 32 and 33 may be rotated. Moreover, there is no restriction | limiting in particular in the shape of the passage holes 32a, 32b, 33a, 33b formed in each disk 32, 33, a position, and a number, As long as the same function as the form of illustration is exhibited, these are It can be set appropriately.

The figure which showed one form of the exhaust heat recovery apparatus of this invention. Sectional drawing along the II-II line of FIG. Sectional drawing along the III-III line of FIG. The expansion perspective view of the slide valve of FIG. The figure which showed the state which the slide valve of FIG. 1 moved to the right direction in the figure from the state of FIG. The flowchart which showed an example of the control routine of the switching control which a control apparatus performs. The figure which showed the exhaust-heat-heat recovery apparatus of the heat exchange promotion state which concerns on a 2nd form. The expansion perspective view of the cylindrical slide valve of FIG. The figure which showed the exhaust-heat recovery apparatus of the heat exchange restriction | limiting state which the cylindrical slide valve of FIG. 7 moved to the left direction in the figure from the state of FIG. The figure which showed the exhaust heat recovery apparatus of the heat exchange acceleration state which concerns on a 3rd form. The top view which showed one disk of the rotary valve. The top view which showed the other disc of the rotary valve. The expanded sectional view along the XIII-XIII line of FIG. The figure which showed the exhaust heat recovery apparatus of the heat exchange restriction | limiting state which concerns on a 3rd form. The expanded sectional view along the XV-XV line of FIG. The figure which showed the modification of the slide valve which concerns on a 1st form.

Explanation of symbols

1A to 1C Exhaust heat recovery device 2 Exhaust passage part 2a Inlet 2b Outlet 3 Heat recovery part 4 Inner pipe (partition wall)
5 Inner passage 6 Outer passage 7 Slide valve (switching means)
8 Inlet side valve element 9 Outlet side valve element 10 Connecting member (connecting means)
21 Cylindrical slide valve (switching means)
22 Cylindrical body (tubular member)
22a passage hole 23 on-off valve 31 rotary valve (switching means)
32 disc (plate)
32a Outer passage hole 32b Inner passage hole 33 Disc (plate-like body)
33a Outer passage hole 33b Inner passage hole 41 Elastic member

Claims (5)

A heat recovery part through which the cooling water of the internal combustion engine flows is arranged on the outer periphery of the exhaust passage part through which the exhaust of the internal combustion engine passes, and between the exhaust gas that passes through the exhaust passage part and the cooling water that flows through the heat recovery part In an exhaust heat recovery device for an internal combustion engine that performs heat exchange,
A partition wall extending in a direction from the inlet to the outlet of the exhaust passage portion so that the exhaust passage portion is divided into an inner passage and an outer passage located outside the inner passage; and passage of exhaust gas in the inner passage. Between a heat exchange acceleration state that prohibits and allows passage of exhaust gas in the outer passage, and a heat exchange restriction state that permits passage of exhaust gas in the inner passage and prohibits passage of exhaust gas in the outer passage. An exhaust heat recovery apparatus for an internal combustion engine, comprising: switching means for switching a passage state of the exhaust gas passing through the exhaust passage portion.   The switching means is located on the inlet side of the exhaust passage part and is capable of opening and closing the outer passage, and is located on the outlet side of the exhaust passage part and is capable of opening and closing the inner passage. The inlet valve body opens the outer passage when the heat exchange is promoted and the outlet valve body closes the inner passage, while the inlet valve body is the heat exchanger when the heat exchange is restricted. Connection means for connecting the inlet-side valve body and the outlet-side valve body so as to be integrally movable so that the outer-side passage is closed and the outlet-side valve body opens the inner passage. Item 2. An exhaust heat recovery apparatus for an internal combustion engine according to Item 1.   The exhaust heat recovery apparatus for an internal combustion engine according to claim 2, wherein the connecting means connects the inlet side valve body and the outlet side valve body with an elastically deformable elastic member interposed therebetween. The switching means closes the outlet of the exhaust passage part at one end when the heat exchange is promoted, and closes the inlet of the exhaust passage part at the other end when the heat exchange is restricted. A cylindrical body provided in a slidable manner along the partition wall; and provided at the other end of the cylindrical body and closing the other end when the heat exchange is promoted; and An on-off valve that opens the other end when the exchange is restricted, and
The peripheral wall portion of the cylindrical body is provided with a passage hole that is opened by the partition wall when the heat exchange is promoted and is closed by the partition wall when the heat exchange is restricted. The exhaust heat recovery device for an internal combustion engine according to claim 1. The switching means includes a pair of plate-like bodies combined in a relatively rotatable state so that a relative position changes between the heat exchange promotion state and the heat exchange restriction state, and It is configured as a rotary valve provided on the inlet side of the exhaust passage part, and each plate-like body of the rotary valve is provided at an inner passage hole provided at a position corresponding to the inner passage and at a position corresponding to the outer passage. Formed with an outer passage hole,
The rotary valve is configured such that when the heat exchange is promoted, the inner passage hole of one plate-like body is closed by the other plate-like body, and the outer passage holes of the respective plate-like bodies are overlapped, Formed in each plate-like body so that the inner passage holes of each plate-like body overlap and the outer passage holes of one plate-like body are blocked by the other plate-like body when in a heat exchange restricted state 2. The exhaust heat recovery apparatus for an internal combustion engine according to claim 1, wherein sizes and positions of the inner passage hole and the outer passage hole are set.

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