JP6380535B2 - Waste heat recovery system - Google Patents

Description

  The present invention relates to a vehicle exhaust heat recovery system including a front heater core and a rear heater core.

  2. Description of the Related Art An exhaust heat recovery system that recovers exhaust gas heat (hereinafter also referred to as exhaust heat) into cooling water is known for the purpose of improving vehicle heater performance and raising the temperature of cooling water at the time of cold start. . JP 2006-105464A describes a configuration in which an exhaust heat recovery device is disposed in a return pipe from a rear heater core to an internal combustion engine as a vehicle exhaust heat recovery system including a front heater and a rear heater.

  However, in the exhaust heat recovery system described in the above-mentioned document, the cooling water circuit in which the front heater core and the rear heater core are connected in parallel is used. Only will flow in. That is, of the cooling water flowing through the cooling water circuit including the heater core, the transmission oil cooler, and the radiator, only the cooling water after passing through the rear heater core contributes to exhaust heat recovery. In such a configuration in which the flow rate of the cooling water passing through the exhaust heat recovery device is small, the amount of heat recovery is limited in order to prevent boiling of the cooling water, so that it is necessary to improve the performance of the front heater and the rear heater. It is difficult to recover the amount of heat from the exhaust gas.

  Therefore, an object of the present invention is to provide a heat recovery system that can recover a sufficient amount of heat to improve the performance of the front heater and the rear heater.

According to an aspect of the present invention, the present invention is applied to a vehicle having a vehicle body in which at least an engine compartment, a vehicle compartment, and an underfloor are separated, and a rear heater core and a front heater core disposed in the vehicle interior are connected in parallel. An exhaust heat recovery system is provided that includes a cooling water circuit and an exhaust heat recovery unit that is disposed under the floor and recovers heat of exhaust gas of the internal combustion engine into cooling water. In this exhaust heat recovery system, the exhaust heat recovery device is connected in series to both the front heater core and the rear heater core, the cooling water passage in which the front heater core is disposed, and the cooling in which the rear heater core is disposed. The junction or junction with the water passage is under the floor of the vehicle body .

FIG. 1 is a cooling water circuit diagram including an exhaust heat recovery system according to the first embodiment. FIG. 2 is a schematic configuration diagram of the exhaust heat recovery device. FIG. 3 is a cooling water circuit diagram as a comparative example. FIG. 4 is a piping diagram of the cooling water passage in the vehicle mounted state of the exhaust heat recovery system according to the first embodiment. FIG. 5A is a layout view of the heater core and the exhaust heat recovery device viewed from the side of the vehicle body. 5B is a cross-sectional view taken along the line VV in FIG. 5A. FIG. 6 is a piping diagram of a cooling water passage as an embodiment. FIG. 7 is a piping diagram of a cooling water passage as a comparative example. FIG. 8 is a cooling water circuit diagram including the exhaust heat recovery system according to the second embodiment. FIG. 9 is a piping diagram of the cooling water passage when the exhaust heat recovery system according to the second embodiment is mounted on a vehicle. FIG. 10 is a piping diagram of a cooling water passage as an embodiment. FIG. 11 is an exhaust path diagram of the internal combustion engine to which the third embodiment is applied. FIG. 12 is a cooling water circuit diagram including the exhaust heat recovery system according to the third embodiment. FIG. 13 is a piping diagram of the cooling water passage when the exhaust heat recovery system according to the third embodiment is mounted on a vehicle. FIG. 14 is a piping diagram of a cooling water passage as another embodiment. FIG. 15 is a cooling water circuit diagram including the exhaust heat recovery system according to the fourth embodiment. FIG. 16 is a piping diagram of a cooling water passage when the exhaust heat recovery system according to the fourth embodiment is mounted on a vehicle. FIG. 17 is a piping diagram of a cooling water passage as an embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a cooling water circuit diagram of an internal combustion engine 1 including an exhaust heat recovery system according to the first embodiment.

  The cooling water supplied to the internal combustion engine 1 by the water pump 2 exchanges heat with the internal combustion engine 1 in a water jacket provided inside the internal combustion engine 1 and is discharged to the cooling water passage 9. In addition to the water pump 2, the cooling water passage 9 is provided with a radiator 3 that releases the heat of the cooling water whose temperature has been increased by heat exchange with the internal combustion engine 1 into the atmosphere.

  The cooling water passage 9 is branched between the internal combustion engine 1 and the radiator 3 into a heater passage 10 and a transmission oil cooler passage 11. The heater passage 10 and the transmission oil cooler passage 11 merge on the downstream side of the exhaust heat recovery unit 7 described later, and further merge with the cooling water passage 9. In the figure, the exhaust heat recovery unit 7 is indicated as EHRS (Exhaust Heat Recirculation System).

  A thermostat 8 is disposed at the junction of the cooling water passage 9, the heater passage 10 and the transmission oil cooler passage 11. The thermostat 8 is configured to open when the coolant temperature reaches a predetermined temperature. In the cooling water circuit of the present embodiment, only the cooling water from the heater passage 10 and the transmission oil cooler passage 11 flows to the water pump 2 when the thermostat 8 is closed.

  In the transmission oil cooler passage 11, a water-cooled transmission oil cooler 4 for cooling the hydraulic fluid of the transmission is disposed.

  In the heater passage 10, a front heater core 5 and a rear heater core 6 connected in parallel, and an exhaust heat recovery device 7 connected in series to both of them are arranged. More specifically, the heater passage 10 includes a front heater core containing side passage 12 connected to the inlet of the front heater core 5 and a rear heater core containing side passage 14 connected to the inlet of the rear heater core 6. Branched. Then, the front heater core outlet side passage 13 connected to the outlet of the front heater core 5 and the rear heater core outlet side passage 15 connected to the outlet of the rear heater core 6 merge, and downstream from this junction. An exhaust heat recovery unit 7 is arranged.

  FIG. 2 is a diagram illustrating an example of the exhaust heat recovery device 7 that can be applied to the present embodiment.

  The exhaust heat recovery device 7 is interposed in the exhaust passage 20 of the internal combustion engine 1, and a heat exchange passage 23 is provided inside the exhaust heat recovery device 7 so as to be exposed to the exhaust gas. When cooling water is caused to flow through the heat exchange passage 23, heat exchange is performed between the cooling water and the exhaust gas, and the heat of the exhaust gas is recovered into the cooling water.

  A bypass passage 21 that branches from the exhaust passage 20 and bypasses the exhaust heat recovery device 7 and joins the exhaust passage 20 again is provided in the exhaust system path of the internal combustion engine 1. A bypass valve 22 for adjusting the flow rate of the exhaust gas flowing through the bypass passage 21 is disposed at a branch portion between the exhaust passage 20 and the bypass passage 21.

  When the exhaust gas flow rate in the bypass passage 21 is reduced by the bypass valve 22, the exhaust gas flow rate flowing into the exhaust heat recovery unit 7 increases, so that the amount of heat that can be recovered in the cooling water (exhaust heat recovery amount) also increases. On the other hand, when the flow rate of the exhaust gas passing through the bypass passage 21 is reduced by the bypass valve 22, the amount of exhaust heat recovery can be reduced.

  When the internal combustion engine 1 is a serial internal combustion engine, the exhaust heat recovery unit 7 is disposed on the downstream side from the junction of the exhaust passages of the cylinders. On the other hand, when the internal combustion engine 1 is a V-type internal combustion engine or a horizontally opposed internal combustion engine, the exhaust heat recovery unit 7 is disposed downstream from the junction of the exhaust passages of both banks.

  In the exhaust heat recovery system having the above-described configuration, the cooling water exiting the internal combustion engine 1 flows through the cooling water passage 9, the heater passage 10 branched from the cooling water passage 9, and the transmission oil cooler passage 11.

  The cooling water flowing through the heater passage 10 branches and flows into the front heater core 5 and the rear heater core 6, joins on the downstream side of the front heater core 5 and the rear heater core 6, and then enters the exhaust heat recovery unit 7. Inflow. The cooling water exiting the exhaust heat recovery unit 7 merges with the cooling water from the transmission oil cooler passage 11, passes through the thermostat 8, and flows into the internal combustion engine 1 again through the water pump 2. When the thermostat 8 is opened, the cooling water that has passed through the radiator 3 is merged with the cooling water that has passed through the exhaust heat recovery device 7.

  In the above cycle, if the exhaust heat recovery by the exhaust heat recovery unit 7 is performed, the cooling water whose temperature has risen passes through the water pump 2 and the internal combustion engine 1 and flows into the front heater core 5 and the rear heater core 6. Performance is improved.

  Here, the improvement of the heater performance will be described in more detail.

  FIG. 3 shows, as a comparative example, a cooling water circuit including the heat recovery system described in JP2006-105464A described above in the same manner as FIG.

  When FIG. 3 and FIG. 1 are compared, the exhaust heat recovery device 7 is arranged downstream of the junction of the front heater core outlet passage 13 and the rear heater core outlet passage 15 in FIG. On the other hand, in FIG. 3, there is a difference that it is arranged in the rear heater core outlet passage 15. That is, while the cooling water that has passed through the front heater core 5 and the cooling water that has passed through the rear heater core 6 flow into the exhaust heat recovery device 7 of the present embodiment, the heat recovery device 7 of the comparative example includes There is a difference that only the cooling water that has passed through the rear heater core 6 flows.

  The smaller the flow rate of the cooling water that passes through the exhaust heat recovery unit 7, the smaller the amount of heat that can be recovered. In addition, the smaller the cooling water flow rate, the easier it is to boil the cooling water, so the upper limit of the amount of exhaust heat recovery for preventing boiling is lowered.

  Therefore, in the configuration of the present embodiment, the flow rate of the cooling water passing through the exhaust heat recovery device 7 is increased as compared with the configuration of FIG. Further, the configuration of the present embodiment makes it difficult for boiling water to boil due to an increase in the flow rate of cooling water as compared with the configuration of FIG.

  Next, the cooling water piping when the above-described heat recovery system is mounted on a vehicle will be described.

  FIG. 4 is a piping diagram of the cooling water passage in the vehicle mounted state of the exhaust heat recovery system in the present embodiment.

  The water pump 2 and the thermostat 8 are omitted. Further, although the front heater core 5 is actually disposed in the vehicle compartment, here, since attention is paid to the piping between the engine compartment and the floor, it is described on the engine compartment side for convenience. The same applies to FIGS. 6, 9, 10, 13, 14, 16, and 17 described later.

  FIG. 5A is a diagram schematically showing the arrangement of the internal combustion engine 1, the front heater core 5, the rear heater core 6, and the exhaust heat recovery device 7 when viewed from the side of the vehicle body. 5B is a cross-sectional view taken along the line VV in FIG. 5A.

  As shown in FIGS. 4 and 5A, the exhaust heat recovery unit 7 is arranged under the floor, and the rear heater core outlet side passage 15 and the front heater core outlet side passage 13 merge under the floor. As a result, the three pipes of the rear heater core entering side passage 14 branched from the cooling water passage 9, the front heater core outlet side passage 13, and the cooling water passage 9 returning from the exhaust heat recovery device 7 to the internal combustion engine 1 are engine. It will straddle the compartment and under the floor.

  As shown in FIGS. 5A and 5B, the cooling water passages 9, 13, 14, and 15 are accommodated in the floor tunnel 30 under the floor. Although omitted in FIG. 5A, as shown in FIG. 5B, the floor tunnel 30 also houses the exhaust pipe 31 and the propeller shaft 32, and the cooling water passage accommodated in the floor tunnel 30 includes the exhaust pipe 31 and It arrange | positions so that it may not interfere with the propeller shaft 32. FIG.

  By the way, when setting the cooling water piping path extending between the engine compartment and the floor, it is necessary to set the cooling water passage and other parts so as not to interfere with each other. Therefore, as the number of pipes extending between the engine compartment and the underfloor increases, it becomes more difficult to set a route. That is, the layout of the piping path is deteriorated. Moreover, since the heat radiation amount from the surface of the pipe increases as the length of the pipe becomes longer, the heater performance decreases. Therefore, it is desirable that the length of the path is shorter.

  Here, the layout property and path length of the piping path of the exhaust heat recovery system of the present embodiment will be described in comparison with the configurations shown in FIGS.

  FIG. 6 is a piping diagram when the junction of the rear heater core outlet passage 15 and the front heater core outlet passage 13 of FIG. 4 is moved into the engine compartment. FIG. 7 is a piping diagram when the exhaust heat recovery unit 7 is not provided.

  As shown in FIG. 7, in a configuration that does not include the exhaust heat recovery device 7, the piping extending between the engine compartment and the floor is provided with a rear heater core containing side passage 14 and a cooling water passage returning from the rear heater core 6 to the internal combustion engine 1. Nine, two. In the configuration shown in FIG. 6, the piping extending between the engine compartment and the underfloor includes a rear heater core containing side passage 14, a rear heater core outlet side passage 15, a front heater core outlet side passage 13, and a heat recovery unit. Four cooling water passages 9 return from the engine 7 to the internal combustion engine 1.

  On the other hand, in the configuration of the present embodiment shown in FIG. 5, the piping extending between the engine compartment and the underfloor includes the rear heater core entrance side passage 14 branched from the cooling water passage 9 and the front heater core exit side passage 13 as described above. And a cooling water passage 9 returning from the exhaust heat recovery device 7 to the internal combustion engine 1.

  In other words, when the piping path as shown in FIG. 6 is used, two pipes extending between the engine compartment and the underfloor increase with the addition of the exhaust heat recovery device 7, whereas according to the present embodiment, the number of pipes increases by one. That's it. Thereby, the deterioration of the layout property of the piping path accompanying the extension of the exhaust heat recovery device 7 can be suppressed.

  Further, the piping length of the rear heater core outlet passage 15 is from the rear heater core 6 to the engine compartment in the configuration of FIG. 6, whereas in the configuration of this embodiment, near the exhaust heat recovery unit 7 under the floor. Is enough. That is, according to the present embodiment, it is possible to suppress an increase in the piping path length accompanying the addition of the exhaust heat recovery unit 7 and to suppress a decrease in heater performance.

  Next, the effects of the above-described embodiment will be summarized.

  The exhaust heat recovery system of the present embodiment includes a cooling water circuit in which a front heater core 5 and a rear heater core 6 are connected in parallel, and an exhaust heat recovery device 7 that recovers heat of exhaust gas of the internal combustion engine 1 into cooling water. And comprising. The exhaust heat recovery device 7 is connected in series to both the front heater core 5 and the rear heater core 6. As a result, both the cooling water that passes through the front heater core 5 and the cooling water that passes through the rear heater core 6 pass through the exhaust heat recovery unit 7, so that a larger amount of exhaust heat recovery is ensured and the heater performance is improved. Can be improved.

  In addition, according to the present embodiment, the front heater core 5 is disposed in the engine compartment, the rear heater core 6 is disposed under the floor of the vehicle body, and the cooling water passages 12 and 13 in which the front heater core 5 is disposed and the rear heater. A branch point or junction with the cooling water passages 14 and 15 in which the core 6 is disposed is under the floor of the vehicle body. Thereby, the deterioration of the layout property of the piping path accompanying the extension of the exhaust heat recovery device 7 can be suppressed. Moreover, the increase in the piping path length accompanying extension of the exhaust heat recovery device 7 can be suppressed, and the deterioration of the heater performance can be suppressed.

  Further, in the present embodiment, the exhaust heat recovery device 7 is located downstream of the junction of the cooling water passage 13 where the front heater core 5 of the cooling water circuit is arranged and the cooling water passage 15 where the rear heater core 6 is arranged. Placed in. As a result, the exhaust heat recovery unit 7 is connected in series only to the rear heater core 6 as shown in FIG. 3 and is not connected to the front heater core 5 in series. Since the flow rate of the coolant passing through 7 increases, the temperature drop when the coolant joins with the coolant from the transmission oil cooler passage 11 or the like can be suppressed.

  By the way, when air bubbles flow into the front heater core 5 and the rear heater core 6, a so-called pop sound is generated and the vehicle interior noise increases. However, according to the present embodiment, even if the temperature rises due to exhaust heat recovery and bubbles are generated, the cooling water exiting the exhaust heat recovery unit 7 passes through the thermostat 8 and the water pump 2 before the front heater. Since it flows into the core 5 and the rear heater core 6, the inflow of bubbles to the front heater core 5 and the rear heater core 6 can be suppressed. That is, according to the present embodiment, an effect of suppressing vehicle interior noise can also be obtained.

(Second Embodiment)
FIG. 8 is a cooling water circuit diagram of the internal combustion engine 1 including the exhaust heat recovery system according to the second embodiment. The arrangement of the exhaust heat recovery device 7 is different from FIG.

  The exhaust heat recovery device 7 of the present embodiment is disposed upstream of the branch point between the front heater core containing side passage 12 and the rear heater core containing side passage 14 of the heater passage 10.

  That is, the cooling water whose temperature has increased in the exhaust heat recovery unit 7 is reduced in temperature by the merge with the cooling water that has passed through the transmission oil cooler passage 11 and the radiator 3 before the front heater core 5 and the rear heater core 6. Flow into.

  FIG. 9 is a piping diagram of the cooling water passage in the vehicle mounted state of the exhaust heat recovery system in the present embodiment. The rear heater core 6 and the exhaust heat recovery device 7 are connected by a rear heater core containing side passage 14 that passes only under the floor without passing through the engine compartment. As a result, the three pipes of the heater passage 10, the front heater core entrance passage 12, and the rear heater core exit passage 15 straddle the engine compartment and the underfloor.

  On the other hand, as shown in FIG. 10, in the configuration in which the branching point between the front heater core containing side passage 12 and the rear heater core containing side passage 14 is in the engine compartment, There are a total of four of the book and the rear heater core containing side passage 14. That is, even in the configuration of the present embodiment, it is possible to suppress the deterioration of the layout of the piping path due to the addition of the exhaust heat recovery unit 7.

  Further, in the configuration of the present embodiment, since the pipe connecting the exhaust heat recovery device 7 and the rear heater core 6 is completed only under the floor, as shown in FIG. As compared with the configuration in which the rear heater core containing side passage 14 branches, the pipe length can be shortened.

  As described above, according to the present embodiment, as in the first embodiment, it is possible to suppress the deterioration of the layout of the piping path due to the addition of the exhaust heat recovery unit 7. Moreover, similarly to 1st Embodiment, the increase in the piping path length accompanying the extension of the exhaust heat recovery device 7 can be suppressed, and the fall of heater performance can be suppressed.

  Further, in the present embodiment, the exhaust heat recovery device 7 is disposed upstream of the branch point between the front heater core-inside passage 12 and the rear heater core-inside passage 14. As a result, the cooling water whose temperature has risen in the exhaust heat recovery unit 7 is reduced in temperature by the merging with the cooling water that has passed through the transmission oil cooler passage 11 and the radiator 3, before the front heater core 5 and the rear heater core. Since it flows into 6, the heater performance can be improved.

(Third embodiment)
The third embodiment is different from the first and second embodiments in that it includes a plurality of exhaust heat recovery devices. In the following description, when it is necessary to distinguish a plurality of exhaust heat recovery units, they are referred to as “first exhaust heat recovery unit 7A” and “second exhaust heat recovery unit 7B”. It is set as the collection device 7 ”.

  FIG. 11 is an exhaust path diagram of the internal combustion engine system including the exhaust heat recovery system according to the present embodiment. The internal combustion engine 1 is a V-type internal combustion engine including a first bank 1A and a second bank 1B, and the first exhaust passage 20A into which the exhaust passages from the cylinders of the first bank 1A are joined from the upstream side. In order, a first exhaust catalyst 40A and a first exhaust heat recovery unit 7A are arranged. Similarly, the second exhaust catalyst 40B and the second exhaust heat recovery device 7B are arranged in the second exhaust passage 20B where the exhaust passages from the respective cylinders of the second bank 1B join.

  The first exhaust passage 20A and the second exhaust passage 20B join together on the downstream side of the first exhaust heat recovery device 7A and the second exhaust heat recovery device 7B to form the exhaust passage 20. A muffler 41 for silencing is arranged in the exhaust passage 20.

  FIG. 12 is a cooling water circuit diagram of the internal combustion engine 1 including the exhaust heat recovery system according to the present embodiment. As shown in the figure, the first exhaust heat recovery unit 7A is connected in series to the downstream side of the front heater core 5, and the second exhaust heat recovery unit 7B is connected in series to the downstream side of the rear heater core 6, The heat recovery device outlet side passage 42 and the second exhaust heat recovery device outlet side passage 43 merge.

  Only the cooling water that has passed through the front heater core 5 passes through the first exhaust heat recovery unit 7A, and only the cooling water that has passed through the rear heater core 6 passes through the second exhaust heat recovery unit 7B. is there. For this reason, compared with the exhaust heat recovery device 7 of 1st Embodiment and 2nd Embodiment, although the cooling water flow rate which passes each waste heat recovery device 7A, 7B decreases, if it sees as the whole exhaust heat recovery system, Equivalent cooling water flow rate can be secured.

  FIG. 13 is a piping diagram of the cooling water passage when the exhaust heat recovery system according to the present embodiment is mounted on a vehicle. As shown in the drawing, the first exhaust heat recovery device outlet side passage 42 and the second exhaust heat recovery device outlet side passage 43 merge under the floor. As a result, the cooling water passage 9 in which the rear heater core entering side passage 14, the front heater core exit side passage 13, and the first exhaust heat recovery device exit side passage 42 and the second exhaust heat recovery device exit side passage 43 merge is formed. It will straddle the engine compartment and the underfloor. That is, there are three pipes that straddle the engine compartment and the underfloor as in the first and second embodiments.

  For comparison, as shown in FIG. 14, when the first exhaust heat recovery device outlet side passage 42 and the second exhaust heat recovery device outlet side passage 43 are merged in the engine compartment, the first exhaust heat recovery device outlet side passage 42 and the second exhaust heat recovery device outlet passage 43 straddle the engine compartment and the underfloor, respectively.

  As described above, in the present embodiment, the exhaust heat recovery unit 7 is disposed in each of the exhaust passages 20A and 20B from each bank of the V-type internal combustion engine 1, and the first exhaust heat recovery unit 7A is used as the front heater core 5. In addition, the second exhaust heat recovery unit 7B is connected to the rear heater core 6 in series. Thereby, similarly to 1st Embodiment and 2nd Embodiment, the deterioration of the layout property of the piping path | route accompanying the expansion of the exhaust heat recovery device 7 can be suppressed. Moreover, the increase in the piping path length accompanying the extension of the exhaust heat recovery device 7 can be suppressed, and the deterioration of the heater performance can be suppressed.

(Fourth embodiment)
The fourth embodiment includes two exhaust heat recovery units 7 as in the third embodiment. That is, as shown in FIG. 11, the exhaust heat recovery devices 7A and 7B are arranged in the exhaust paths 20A and 20B from the banks 1A and 1B of the V-type internal combustion engine 1, respectively. However, the cooling water circuit for connecting the front heater core 5 and the rear heater core 6 to the two exhaust heat recovery devices 7A and 7B is different from the third embodiment. Hereinafter, the difference from the third embodiment will be mainly described.

  FIG. 15 is a cooling water circuit diagram of the internal combustion engine 1 including the exhaust heat recovery system according to the present embodiment. As shown in the drawing, the first exhaust heat recovery unit 7 </ b> A is disposed downstream of the junction of the front heater core outlet side passage 13 and the rear heater core outlet side passage 15. The second exhaust heat recovery unit 7B is arranged in series on the downstream side of the first exhaust heat recovery unit 7A.

  FIG. 16 is a piping diagram of the cooling water passage when the exhaust heat recovery system according to this embodiment is mounted on a vehicle. As shown in the drawing, the front heater core outlet passage 13 and the rear heater core outlet passage 15 merge under the floor. As a result, the rear heater core entrance side passage 14, the front heater core exit side passage 13, and the cooling water passage 9 on the downstream side of the second exhaust heat recovery device 7B straddle the engine compartment and the underfloor. That is, there are three pipes that straddle the engine compartment and the underfloor as in the first embodiment, the second embodiment, and the third embodiment.

  For comparison, as shown in FIG. 17, when the rear heater core outlet passage 15 and the front heater core outlet passage 13 are merged in the engine compartment, the rear heater core outlet passage 15 and the front heater core outlet passage 13 are joined. And straddle the engine compartment and the underfloor respectively.

  As described above, in the present embodiment, the first exhaust heat recovery device 7A and the second exhaust heat recovery device 7B disposed in each of the exhaust passages 20A and 20B from each bank of the V-type internal combustion engine 1 are replaced with the front heater. The core outlet side passage 13 and the rear heater core outlet side passage 15 are connected in series downstream from the junction. Even with such a configuration, as in the first embodiment and the second embodiment, it is possible to suppress the deterioration of the layout performance of the piping path due to the addition of the exhaust heat recovery unit 7. Moreover, the increase in the piping path length accompanying the extension of the exhaust heat recovery device 7 can be suppressed, and the deterioration of the heater performance can be suppressed.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

Claims (4)

Applied to a vehicle having a vehicle body at least divided into an engine compartment, a vehicle compartment, and an underfloor;
A cooling water circuit in which a rear heater core and a front heater core disposed in the vehicle interior are connected in parallel;
An exhaust heat recovery device disposed under the floor and recovering heat of exhaust gas of the internal combustion engine into cooling water;
In an exhaust heat recovery system comprising:
The exhaust heat recovery device is connected in series to both the front heater core and the rear heater core ,
Wherein the cooling water passage front heater core are disposed, the branch point or merge point of the coolant passages rear heater core is disposed, the exhaust heat recovery system Ru floor near the vehicle body. The exhaust heat recovery system according to claim 1 ,
The exhaust heat recovery unit is an exhaust heat recovery system disposed downstream of a junction of a cooling water passage in which the front heater core of the cooling water circuit is disposed and a cooling water passage in which the rear heater core is disposed. system. The exhaust heat recovery system according to claim 1 ,
The exhaust heat recovery device is an exhaust heat recovery system arranged upstream of a branch point between a cooling water passage where the front heater core is arranged and a cooling water passage where the rear heater core is arranged. The exhaust heat recovery system according to claim 1 ,
The internal combustion engine has a plurality of cylinder rows;
The exhaust heat recovery unit includes a first exhaust heat recovery unit that recovers heat of exhaust gas of one of the cylinder rows, and a second exhaust heat recovery unit that recovers heat of exhaust gas of the other cylinder row. Waste heat recovery system consisting of

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