JP2016044666A - Exhaust heat recovery device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust heat recovery device of internal combustion engine including exhaust gas recirculation equipment in which an efficient heat-recovery can be carried out without damaging exhaust efficiency.SOLUTION: This invention comprises a main exhaust channel 11 for feeding exhaust gas of an internal combustion engine; a bypass channel 12 branched from this main exhaust channel and merging with the main exhaust channel; a heat exchanger 10 placed at the bypass channel to feed exhaust gas in the bypass channel to perform a heat exchanging operation with cooling medium of the internal combustion engine; and a valve device 20 at a downstream side of the heat exchanger to open or close the main exhaust channel and the bypass channel. The bypass channel between this valve device and the heat exchanger is communicated with and connected to exhaust gas recirculation equipment through a recirculation channel 13.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an exhaust heat recovery device for an internal combustion engine of an automobile, and more particularly to an exhaust heat recovery device suitable for an internal combustion engine equipped with an exhaust gas recirculation device.

  2. Description of the Related Art In an internal combustion engine of an automobile, there is known an apparatus that heats a cooling medium using the heat of exhaust gas from the internal combustion engine when the temperature of the cooling medium is low, such as during cold start. In this regard, the main exhaust passage for introducing the exhaust gas of the internal combustion engine and a bypass passage branched from the main exhaust passage are introduced, and the exhaust gas in the bypass passage is introduced to exchange heat with the cooling medium. An exhaust heat recovery device equipped with a heat exchanger has attracted attention. For example, Patent Document 1 discloses that an “exhaust pipe part from which exhaust gas is exhausted, a branch from the exhaust pipe part and installed above the exhaust pipe part, and heat exchange between the exhaust gas and the cooling medium. An exhaust heat recovery device to be performed; a cooling pipe for introducing the cooling medium into the exhaust heat recovery device; and an exhaust gas flow path installed on the side of the exhaust pipe portion and introduced into the exhaust pipe portion. An "exhaust heat recovery apparatus including an actuator that drives a switching valve that switches to either the exhaust pipe portion or the exhaust heat recovery device" is disclosed (described in paragraph [0006] of Patent Document 1).

  Also, an internal combustion engine equipped with an exhaust gas recirculation device (EGR) that recirculates part of the exhaust gas to the intake side is known. Recently, in order to improve intake charging efficiency from the viewpoint of fuel consumption rate. In order to cool the exhaust gas for recirculation, a heat exchanger is provided in the exhaust gas recirculation flow path, and this heat exchanger is called an EGR cooler. For example, Patent Document 2 states that “an exhaust pipe that guides exhaust discharged from a heat engine to the atmosphere side, a waste heat recovery unit that recovers heat from at least the exhaust, and heat exhaust that has been cooled by the waste heat recovery unit. An exhaust device for a heat engine is disclosed (including an exhaust gas recirculation pipe returning to the intake side of the engine) (described in paragraph [0006] of Patent Document 2; however, the reference numerals are omitted).

  Furthermore, Patent Document 3 relates to an exhaust heat recovery system, and proposes to use the above-mentioned EGR cooler as an exhaust heat recovery unit for the purpose of recovering heat of exhaust gas and providing it for warm-up promotion and the like. (Described in paragraphs [0003], [0004], [0009], etc. of Patent Document 3). Patent Document 4 states that “in an exhaust system of an internal combustion engine having at least two flow paths that constitute an exhaust flow path connected to the internal combustion engine, the flow is switched by a single valve member and each An “exhaust device capable of appropriately adjusting the flow path area” is disclosed (described in paragraph [0014] of Patent Document 4).

JP 2014-095362 A JP 2003-193832 A JP 2005-273582 A Japanese Patent No. 4486963

  In the above-mentioned Patent Document 2, it is proposed to use the low-temperature exhaust gas discharged from the exhaust heat recovery device having a combustion heating function as the exhaust gas for recirculation and eliminate the EGR cooler. In the exhaust system described in Document 2, as described in Patent Document 1, the main exhaust channel and the bypass channel that bypasses this and the heat exchanger is interposed are not completely separated, Moreover, the valve apparatus which switches both flow paths is not arrange | positioned. For this reason, after engine warm-up that does not require heat recovery by a heat exchanger, the exhaust gas discharged from the downstream side of the catalyst cannot be discharged directly to the exhaust pipe and the silencer, and the output during medium to high rotation is low. Become. In addition, since the high-temperature exhaust gas at the time of medium rotation or high rotation is introduced into the heat exchanger, the burden on the cooling system becomes large.

  On the other hand, in the exhaust device described in Patent Document 3, it has been proposed to use an EGR cooler as a waste heat recovery device, but it does not include a heat exchanger interposed in the bypass channel, Therefore, as a matter of course, the relationship between the heat exchanger and the EGR cooler is not mentioned. Note that any of the two flow paths, ie, the main exhaust flow path and the bypass flow path, may be used as the main exhaust flow path. For example, in Patent Document 4, they are used in the reverse relationship.

  Therefore, the present invention provides an exhaust heat recovery device for an internal combustion engine equipped with an exhaust gas recirculation device, which can perform efficient heat recovery without impairing the exhaust efficiency that affects the performance of the internal combustion engine. The issue is to provide.

  To achieve the above object, the present invention provides a main exhaust passage for introducing exhaust gas of an internal combustion engine equipped with an exhaust gas recirculation device, a branch from the main exhaust passage, and joins the main exhaust passage. A bypass flow path, a heat exchanger interposed in the bypass flow path, introducing exhaust gas in the bypass flow path and exchanging heat with the cooling medium of the internal combustion engine, and the downstream side of the heat exchanger A valve device that opens and closes a main exhaust passage and the bypass passage, and is configured to communicate and connect the bypass passage between the valve device and the heat exchanger to the exhaust gas recirculation device; is there.

  In the exhaust heat recovery apparatus, the valve device may include a first valve member that opens and closes the main exhaust passage and a second valve member that opens and closes the bypass passage.

  Alternatively, the valve device may include a single valve member that continuously sets the other channel area in a state in which one of the main exhaust channel and the bypass channel is closed. Further, the single valve member is driven according to the operating state of the internal combustion engine, and the main exhaust passage and the bypass passage are switched, and the main exhaust passage and the bypass passage are switched. It is preferable to provide a control device that adjusts each channel area.

  Since this invention is comprised as mentioned above, there exist the following effects. That is, the exhaust heat recovery apparatus of the present invention includes a valve device that opens and closes the main exhaust flow path and the bypass flow path on the downstream side of the heat exchanger, and exhausts the bypass flow path between the valve device and the heat exchanger. Since it is configured to communicate with the gas recirculation device, efficient heat recovery can be performed without impairing the exhaust efficiency. In particular, since the appropriate exhaust gas for recirculation can be always supplied without the need for a conventional EGR cooler, the exhaust system as a whole can be downsized.

  In the above exhaust heat recovery apparatus, if the valve device includes a first valve member that opens and closes the main exhaust passage and a second valve member that opens and closes the bypass passage, the operating state of the internal combustion engine Accordingly, the exhaust flow path and the bypass flow path can be appropriately switched. Regardless of the flow path switching, the recirculation exhaust gas can always be supplied from the bypass flow path between the valve device and the heat exchanger.

  Alternatively, if the valve device includes a single valve member that continuously sets the area of the other flow path in a state where one of the main exhaust flow path and the bypass flow path is closed, a single valve The main exhaust flow path and the bypass flow path can be opened and closed only by the members, and the flow area of each flow path can be easily adjusted.

  Further, in the exhaust heat recovery apparatus, the single valve member is driven in accordance with the operating state of the internal combustion engine, and the main exhaust passage and the bypass passage are switched, and the main exhaust passage and the bypass flow are switched. If a control device that adjusts the flow area of each of the paths is provided, for example, when the internal combustion engine is running at low or medium speed, it is possible to appropriately reduce the exhaust and add a silencing function.

It is a front view of the exhaust apparatus provided with the exhaust heat recovery apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the fully closed state of the main exhaust flow path in the exhaust heat recovery apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the substantially fully closed state of the detour flow path in the exhaust heat recovery apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the fully closed state of the main exhaust flow path in the exhaust heat recovery apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the substantially fully closed state of the detour flow path in the exhaust heat recovery apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the fully closed state of the main exhaust flow path in the exhaust heat recovery apparatus which concerns on further another embodiment of this invention. It is sectional drawing which shows the fully closed state of the detour flow path in the exhaust heat recovery apparatus which concerns on further another embodiment of this invention. It is sectional drawing which shows the flow control state of the exhaust gas for recirculation in the exhaust heat recovery apparatus which concerns on another embodiment of this invention. It is a front view of the exhaust apparatus provided with the conventional exhaust heat recovery apparatus.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of an exhaust system equipped with an exhaust heat recovery system according to an embodiment of the present invention. An exhaust pipe EP1 is connected to an internal combustion engine ENG equipped with an exhaust gas recirculation device EGR via a head flange HF. Is connected, and the catalytic converter CC is connected to the exhaust pipe EP1. The catalytic converter CC is connected to the exhaust heat recovery device 1 via an exhaust pipe EP2, and is further connected to a silencer (not shown) via an exhaust pipe EP3. The catalytic converter CC of the present embodiment includes a start catalytic converter and a main catalytic converter (shown in FIG. 9) as in the case of the conventional catalytic converter, but description thereof will be omitted.

  The exhaust pipe EP2 is connected to the main exhaust flow path 11 shown in FIGS. 2 and 3, and the heat exchanger 10 is disposed in the bypass flow path 12 branched from the main exhaust flow path 11, and at the downstream side of the heat exchanger 10, A valve device 20 that opens and closes the exhaust flow path 11 and the bypass flow path 12 is provided, and the bypass flow path 12 between the heat exchanger 10 and the valve device 20 is recirculated through the recirculation flow path 13. It is connected in communication with the device EGR. The exhaust gas in the bypass channel 12 is introduced into the heat exchanger 10 and the cooling medium of the internal combustion engine ENG is introduced from the medium introduction port EC, and heat exchange between the exhaust gas and the cooling medium is performed. The later exhaust gas is discharged to the recirculation flow path 13 and supplied to the exhaust gas recirculation device EGR as exhaust gas for recirculation. Normally, an EGR valve EGV is mounted as shown in FIG. 1 in order to adjust the flow rate of the recirculation exhaust gas recirculated to the exhaust gas recirculation device EGR.

  As shown in FIGS. 2 and 3, the exhaust heat recovery apparatus 1 of the present embodiment includes a lower housing 1 a disposed below the vehicle, and an upper housing 1 b joined to the upper housing 1 b and disposed above the vehicle. A main exhaust passage 11 is formed in the housing 1a, a bypass passage 12 is formed in the upper housing 1b, and a heat exchanger 10 is accommodated. The heat exchanger 10 has a plurality of cooling medium passages (typically represented by 10j) through which the cooling medium of the internal combustion engine ENG circulates, and the exhaust gas in the bypass passage 12 passes between them to generate heat. Exchange is performed, the cooling medium is heated and recirculated to the internal combustion engine ENG, and the cooled recirculation exhaust gas is supplied to the exhaust gas recirculation device EGR (FIG. 1) via the recirculation flow path 13. The

  The valve device 20 of the present embodiment is disposed on the downstream side of the heat exchanger 10, and opens and closes the first valve member 21 that opens and closes the opening 11 a of the main exhaust passage 11 and the opening 12 a of the bypass passage 12. The second valve member 22 is provided. As shown in FIGS. 2 and 3, the second valve member 22 is formed by an arc-shaped pipe joined to the first valve member 21, and is centered on a pivot shaft C supported by the lower housing 1 a. Further, the first valve member 21 is configured to swing integrally. Since the actuator for driving the valve device 20 is the same as before, the description thereof is omitted.

  In the exhaust heat recovery apparatus 1 configured as described above, the embodiment shown in FIG. 2 prioritizes exhaust heat recovery in the warming-up process (in the cold state) of the internal combustion engine ENG, and warms up and heats up the cooling medium quickly. The main exhaust passage 11 is fully closed by the first valve member 21 and the bypass passage 12 is fully open. As a result, as shown by the arrow of the flow of exhaust gas, all of the exhaust gas flowing in from the exhaust pipe EP2 flows into the heat exchanger 10 through the opening 12b on the introduction side, and is actively recovered (cooled), The exhaust gas for recirculation is supplied from the recirculation flow path 13 to the exhaust gas recirculation device EGR, and is discharged into the main exhaust flow path 11 from the opening 12a on the discharge side. In this case, even if the bypass flow path 12 is in a communication state, the required cooled recirculation exhaust gas is reliably supplied to the exhaust gas recirculation device EGR via the recirculation flow path 13. . In the warm-up process (during cold), it is preferable that the main exhaust passage 11 is fully closed by the first valve member 21, but it is not essential to completely shut off the exhaust gas. As long as the exhaust flow rate of 11 is reduced by a necessary amount, it is not always necessary to be in the fully closed state, and it may be in a slightly opened state.

  On the other hand, the mode of FIG. 3 shows a state in which exhaust efficiency is prioritized during medium to high rotation of the internal combustion engine ENG. The main exhaust passage 11 is fully opened and the bypass passage 12 is the second. The valve member 22 is substantially fully closed. As a result, most of the exhaust gas is discharged from the main exhaust passage 11 to the exhaust pipe EP3, but a part of the exhaust gas is introduced into the heat exchanger 10 through the opening 12b and cooled, and the exhaust gas for recirculation and The recirculation flow path 13 is then supplied to the exhaust gas recirculation device EGR. In this case, even if the bypass flow path 12 is substantially closed by the second valve member 22, the required cooled recirculation exhaust gas is reliably exhausted via the recirculation flow path 13. It is supplied to the recirculation device EGR.

  Thus, the heat exchanger 10 in the exhaust heat recovery apparatus 1 of the present embodiment continues heat recovery in any state of FIG. 2 and FIG. Recovery is performed. In this regard, in the conventional (switchable) exhaust heat recovery device, heat recovery after warming is not required, but rather the exhaust gas is isolated from the heat exchanger to prevent heat exchange with the cooling medium. However, in this embodiment, heat recovery is always premised, and it is not necessary to take such measures. However, the constant heat recovery increases the heat burden on the water cooling system, ie, the radiator, water piping, and switching valve, compared to conventional devices, but the conventional EGR cooler can be abolished or miniaturized and the heat load can be reduced. It will be offset and will be offset.

  4 and 5 show an exhaust heat recovery apparatus 1x according to another embodiment of the present invention, in which a main exhaust passage 111 is formed in a housing 1c and a bypass passage is formed around the main exhaust passage 111. 112 is formed, these flow paths merge at the exhaust flow path 110, and the heat exchanger 100 is interposed in the bypass flow path 112. This heat exchanger 100 also has a plurality of cooling medium passages (typically represented by 100j) through which the cooling medium of the internal combustion engine ENG circulates, and the exhaust gas in the bypass passage 112 passes between them. Heat exchange is performed, the cooling medium is heated and recirculated to the internal combustion engine ENG, and the cooled recirculation exhaust gas is supplied to the exhaust gas recirculation device EGR via the recirculation flow path 113. In the present embodiment, the heat exchanger 100 is interposed between the cylindrical body constituting the main exhaust flow path 111 and the cylindrical body portion of the housing 1c. By comprising in this way, the whole apparatus can be formed small compared with embodiment described in FIG.2 and FIG.3.

  Specifically, as shown in FIG. 4, a circle that is divided in the left-right direction of the vehicle around the cylinder constituting the main exhaust passage 111 and that has the axis of the main exhaust passage 111 as the center (side view). A pair of arc-shaped heat exchangers 100 are disposed, and the cooling medium is introduced from an inlet 100i provided in the lower part of the vehicle in the housing 1c, and passes through a plurality of cooling medium flow paths 100j, and then the upper part of the vehicle. The exhaust port 100k provided in the engine is recirculated to the internal combustion engine ENG (FIG. 1). Thus, the exhaust gas flowing into the main exhaust flow path 111 from the exhaust pipe EP2 passes through the cooling medium flow path 100j from the opening 112b on the introduction side, heat exchange is performed, and the cooling medium is heated. While being recirculated to the internal combustion engine ENG, the cooled recirculation exhaust gas is supplied to the exhaust gas recirculation device EGR (FIG. 1) via the recirculation flow path 113.

  The valve device 120 of the present embodiment also includes a first valve member 121 that opens and closes the opening 111a of the main exhaust flow path 111, and a second valve member 122 that opens and closes the opening 112a of the bypass flow path 112. . As shown in FIGS. 4 and 5, the second valve member 122 is composed of an arcuate curved member formed integrally with the first valve member 121, and is a pivot shaft supported by the housing 1c. It is configured to swing integrally with the first valve member 121 around C and open and close the opening 112a. Since the actuator for driving the valve device 120 is the same as before, the description thereof is omitted.

  FIG. 4 shows a state in which exhaust heat recovery is prioritized in the warming-up process (when cold) of the internal combustion engine ENG, and the cooling medium is quickly warmed and used for warming up and heating. The first valve member 121 is fully closed, and the bypass flow path 112 is fully open. As a result, all of the exhaust gas flows into the heat exchanger 10 from the communication hole 112b and is actively recovered (cooled) to become exhaust gas for recirculation, and the exhaust gas is recirculated through the recirculation passage 113. While being supplied to the apparatus EGR, it is discharged into the exhaust passage 110 from the opening 112a. In this case, even if the bypass flow path 112 is in a communication state, the required cooled recirculation exhaust gas is reliably supplied to the exhaust gas recirculation device EGR via the recirculation flow path 113. . In this embodiment as well, in the warm-up process (during cold), it is preferable that the main exhaust passage 111 is fully closed by the first valve member 121, but it is not essential to completely shut off the exhaust gas. As long as the exhaust flow rate of the main exhaust passage 111 is reduced by a necessary amount, it is not necessarily required to be in the fully closed state, and may be slightly opened.

  On the other hand, the mode of FIG. 5 shows a state in which the exhaust efficiency is prioritized during the middle to high rotation of the internal combustion engine ENG after the warm-up process is finished. The path 112 is substantially fully closed by the second valve member 122. As a result, most of the exhaust gas is discharged from the main exhaust passage 111 to the exhaust pipe EP3 (FIG. 1), but part of the exhaust gas is introduced into the heat exchanger 100 through the communication hole 112b, cooled, and recirculated. The exhaust gas is supplied to the exhaust gas recirculation device EGR. In this case, even if the bypass flow path 112 is substantially closed by the second valve member 122, the required cooled recirculation exhaust gas is reliably supplied to the exhaust gas recirculation device EGR. . Thus, in any state of FIG. 4 and FIG. 5 and also in the intermediate process, heat recovery by the heat exchanger 100 is continued, and recovery is always performed.

  As described above, in the exhaust heat recovery devices (1, 1x) having various structures, the heat exchanger 10 and the valve devices (second valve members 12, 122) for opening and closing the bypass channels (12, 112) are provided. By providing the recirculation flow path (13, 113) between them, the recirculated exhaust gas that has been cooled can be always supplied to the exhaust gas recirculation device EGR regardless of the operating state. 2 to 5 are configured to open and close the main exhaust flow path and the bypass flow path by a plurality of valve members, but both the flow paths are opened and closed by a single valve member. It can also comprise so that the flow-path area of a flow path can be adjusted.

  6 and 7 show an exhaust heat recovery apparatus 1y according to still another embodiment of the present invention, and substantially the same elements in the embodiments shown in FIGS. 2 and 3 are denoted by the same reference numerals. doing. The valve device 200 of the present embodiment is a single valve member 210 that can continuously set the other channel area in a state where one of the main exhaust channel 11 and the bypass channel 12 is closed (fully closed state). The valve member 210 is driven in accordance with the operating state of the internal combustion engine ENG, and the main exhaust passage 11 and the bypass passage 12 are switched, and the main exhaust passage 11 and the bypass passage 12 are switched. Each channel area is adjusted.

  The valve member 210 according to the present embodiment includes a valve body 211 having a fan-shaped cross section, and a pivotal portion C of the main part of the valve body 211 is swingable to a connecting portion between the main exhaust passage 11 and the bypass passage 12. The outer peripheral wall surface 212 of the valve body 211 is slidably disposed on the inner wall surface of the bypass channel 12 and the inner wall surface of the main exhaust channel 11. The valve member 210 is connected to the actuator ACT, and is driven and controlled by the electronic control unit ECU according to the operating state of the internal combustion engine ENG via the actuator ACT. The actuator ACT has, for example, a step motor (not shown), which is precisely rotated or held and fixed by the electronic control unit ECU. In the electronic control unit ECU, based on detection signals of various sensors (oxygen sensor, pressure sensor, water temperature sensor, rotation sensor, accelerator opening sensor, etc.), the operating status of the internal combustion engine ENG, the operating status of the driver's accelerator pedal, etc. Further, the stepping motor is monitored so that the vehicle posture and the braking situation are monitored, and in a predetermined cycle, the optimum position of the valve member 210 at that time is calculated and rotated to that position or stopped at that position. Drive signal is output. Thus, a control device is configured by the actuator ACT and the electronic control unit ECU, and the flow switching between the main exhaust flow path 11 and the bypass flow path 12 (opening and closing of each flow path) is performed. The flow area adjustment of each of the exhaust flow path 11 and the bypass flow path 12 is performed.

  In FIG. 6, the main exhaust passage 11 is fully closed by the valve member 210, and the exhaust passage is switched to the bypass passage 12 side. Accordingly, all of the exhaust gas is introduced into the bypass flow path 12 and is heat-exchanged by the heat exchanger 10, and then discharged from the opening 12c to the main exhaust flow path 11. Furthermore, in this embodiment, the flow path area of the bypass flow path 12 is adjusted so as to meet the output requirements and the silencing requirements by driving the valve member 210 while the main exhaust flow path 11 is maintained in the fully closed state. Adjusted. For example, the gap (b) between the valve member 210 and the bypass channel 12 is adjusted, and for example, the “flow adjustment function” is exhibited by the “throttle function” of the valve member 210. Since the valve member 210 can be driven steplessly, the flow passage area of the bypass flow passage 12 can be arbitrarily adjusted with the main exhaust flow passage 11 maintained in a fully closed state.

  7 shows a state after the internal combustion engine ENG is warmed up. The bypass flow path 12 is fully closed by the valve member 210, and the exhaust flow path is switched to the main exhaust flow path 11 side. Accordingly, all of the exhaust gas is introduced into the main exhaust passage 11 and is discharged as it is. In this case, in this embodiment, the flow passage area of the main exhaust flow passage 11 is adapted to meet the output requirements and the silencing requirements by driving the valve member 210 while the bypass flow passage 12 is maintained in the closed state. Is adjusted. For example, as shown in the gap (c) in FIG. 7, the flow area of the main exhaust flow path 11 is adjusted to be smaller than the maximum flow area. Even in this state, the bypass channel 12 (and the recirculation exhaust gas supply) can be arbitrarily controlled by the valve member 210. That is, even if the bypass flow path 12 is fully closed, the exhaust gas flow rate (and flow path resistance) of the main exhaust flow path 11 can be arbitrarily changed while ensuring the supply of the recirculation exhaust gas. Can do. Therefore, it is possible to add a noise reduction function by appropriately adjusting the exhaust throttle and imparting exhaust resistance during low to medium rotation of the internal combustion engine ENG. In addition, as shown in FIG. 8, if the recirculation flow path 13 is provided at a position that is opened and closed by the rotation of the valve member 210, it is possible to control even the flow rate of the recirculation exhaust gas.

  As described above, in any of the modes of FIGS. 6 and 7, not only switching (opening / closing) between the fully open state and the fully closed state with respect to the main exhaust flow path 11 and the bypass flow path 12 but also the flow rate between them (fully closed state). The flow rate on the side that is not present) is also controlled by the valve member 210, whereby arbitrary flow rate control is possible, and the following control is possible. That is, the recirculation exhaust gas supply amount in the state of FIG. 6 can be controlled. Further, in the state shown in FIG. 7, it is possible to perform noise reduction control by the exhaust throttle according to the traveling state. Further, in order to suppress the exhaust noise that tends to occur during the cold immediately after the start of the internal combustion engine ENG, it is possible to perform the control that minimizes the opening degree (c) of FIG. 7 for a certain time immediately after the start. Thus, the flow rate of the recirculation exhaust gas is basically controlled by the EGR valve (EGV in FIG. 1) mounted on the internal combustion engine ENG. As an auxiliary, the control of the recirculation exhaust gas supply amount is performed. It can be performed. In addition, since the switching control is possible with a single valve member 210 instead of a plurality of valve members, the mechanism can be operated simply and reliably, and it is also effective in terms of cost and weight. Note that, as in the above-described embodiment, the main exhaust passage 11 and the bypass passage 12 do not necessarily need to be fully closed, and may be slightly open.

  FIG. 9 shows an exhaust system equipped with a conventional exhaust heat recovery device. A start catalytic converter (SC) is connected to the exhaust pipe EP1, and a main catalytic converter (MC) is connected to a position away from the start catalytic converter (SC). Yes. The main catalytic converter (MC) is connected to an exhaust heat recovery device (HEA) via an exhaust pipe EP2, and is further connected to a silencer (MF) via an exhaust pipe EP3. The downstream side of the start catalytic converter (SC) is connected to an exhaust gas recirculation device (not shown in FIG. 9) via an EGR cooler (indicated by EGC in FIG. 9). Thus, as is apparent from a comparison between the exhaust device shown in FIG. 9 and the embodiment of the present invention shown in FIG. 1, according to the exhaust heat recovery device 1 shown in FIG. 1, the exhaust heat shown in FIG. In addition to including both the recovery device (HEA) and the EGR cooler (EGC), it is possible not only to reduce the size and weight, but also to efficiently and appropriately perform exhaust gas recirculation as described above.

1, 1x, 1y Exhaust heat recovery device 10, 100 Heat exchanger 11, 111 Main exhaust passage 12, 112 Detour passage 13, 113 Recirculation passage 20, 120, 200 Valve device 21, 121 First valve member 22, 122 Second valve member 210 Valve member ENG Internal combustion engine EGR Exhaust gas recirculation device CC Catalytic converter

Claims (4)

  A main exhaust passage for introducing exhaust gas of an internal combustion engine equipped with an exhaust gas recirculation device; a bypass passage branched from the main exhaust passage and joined to the main exhaust passage; and an intervening passage in the bypass passage A heat exchanger that introduces exhaust gas in the bypass flow path and exchanges heat with the cooling medium of the internal combustion engine, and opens and closes the main exhaust flow path and the bypass flow path on the downstream side of the heat exchanger. An exhaust heat recovery device for an internal combustion engine comprising a valve device, wherein the bypass flow path between the valve device and the heat exchanger is connected to the exhaust gas recirculation device.   2. The exhaust heat of the internal combustion engine according to claim 1, wherein the valve device includes a first valve member that opens and closes the main exhaust passage and a second valve member that opens and closes the bypass passage. Recovery device.   2. The valve device according to claim 1, further comprising a single valve member configured to continuously set a flow path area of the other while closing one of the main exhaust flow path and the bypass flow path. An exhaust heat recovery apparatus for an internal combustion engine as described.   The single valve member is driven according to the operating state of the internal combustion engine, and the main exhaust passage and the bypass passage are switched, and each of the main exhaust passage and the bypass passage is switched. The exhaust heat recovery device for an internal combustion engine according to claim 3, further comprising a control device for adjusting a flow path area.

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