JP2018109384A - Exhaust heat recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact exhaust heat recovery system which can warm cooling water, and can generate electric power.SOLUTION: A exhaust heat recovery system (20) includes a branch portion (30) branching exhaust gas introduced from an exhaust gas introduction port (31a) in two flow passages, a first flow passage (22) connected with the branch portion (30) and having an upstream side end facing the exhaust gas introduction port (31a), a second flow passage (24) provided along the first flow passage (22) and having an upstream side end connected with the branch portion, and a heat exchanger (60) provided in the second flow passage (24) and warming water flowing inside with heat of the exhaust gas. The first flow passage (22) has a thermoelectric power generating device (40) that generates power on the basis of a temperature difference between the heat of the exhaust gas and heat of a medium flowing inside.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an improved exhaust heat recovery apparatus.

  2. Description of the Related Art An exhaust heat recovery apparatus that warms a medium in a heat exchanger using heat of exhaust gas generated in an internal combustion engine is known. As a conventional technique related to such an exhaust heat recovery apparatus, there is a technique disclosed in Patent Document 1.

  Reference is made to FIG. FIG. 6A is a diagram showing FIG. 5 of Patent Document 1 again. The reference numerals are appropriately reassigned. As shown in Patent Document 1, an exhaust heat recovery apparatus 100 includes a first flow path 101 through which exhaust gas flows, a second flow path 102 provided along the first flow path 101, and a second flow path. A heat exchanger 103 that is provided in the passage 102 and that heats the cooling water that flows inside by the heat of the exhaust gas; ing.

  By the way, a thermoelectric generator is known as a device that uses the heat of such exhaust gas. Patent Document 1 discloses a thermoelectric power generation apparatus in addition to an exhaust heat recovery apparatus.

  Reference is made to FIG. FIG. 6B is a diagram showing FIG. 11 of Patent Document 1 again. The reference numerals are appropriately reassigned. As shown in Patent Document 1, a thermoelectric power generation apparatus 200 includes an exhaust gas path 201 through which exhaust gas passes, a medium path 202 that is provided along the exhaust gas path 201 via a gap, and through which a medium passes. And a thermoelectric element 203 that is disposed in a gap between the exhaust gas path 201 and the medium path 202 and generates electric power based on a temperature difference between the heat of the exhaust gas and the heat of the medium.

  Reference is also made to FIG. If the cooling water can be warmed by the exhaust gas and power generation can be performed, energy can be used efficiently, which is desirable.

  On the other hand, in order to arrange both the exhaust heat recovery apparatus 100 and the thermoelectric power generation apparatus 200 in a limited arrangement space, it is necessary to efficiently use the space.

JP 2014-95362 A

  It is an object of the present invention to provide an exhaust heat recovery device that is capable of warming cooling water and generating power while being compact.

According to the first aspect of the present invention, the exhaust gas introduction port into which the exhaust gas generated in the engine is introduced, the branch portion for branching the exhaust gas introduced from the exhaust gas introduction port into two flow paths, and the branch A first flow path that is connected to the first section and has an upstream end facing the exhaust gas inlet, and a second flow path that is provided along the first flow path and has an upstream end connected to the branch section. A heat exchanger that is provided in the second flow path and that heats the water flowing inside by the heat of the exhaust gas, a thermoactuator that is connected to the heat exchanger and that operates according to the temperature of the water, and that is operated by the thermoactuator A waste heat recovery device having a valve device capable of opening and closing the first flow path,
An exhaust heat recovery device is provided, wherein the first flow path includes a thermoelectric power generation device that generates power based on a temperature difference between heat of the exhaust gas and heat of a medium flowing inside. The

  According to a second aspect of the present invention, preferably, the first flow path is arranged in the vertical direction and along the engine so that the exhaust gas flows in the vertical direction.

  In the invention according to claim 1, the thermoelectric generator is provided in the first flow path disposed downstream of the exhaust gas inlet, and the heat exchanger is provided in the second flow path branched from the first flow path. ing. Immediately after the engine is running, the water temperature is low. At this time, the valve closes the first flow path. As a result, the exhaust gas flows through the second flow path and warms the water flowing through the heat exchanger. This warms up rapidly. When the temperature of water reaches a predetermined temperature, the thermoactuator operates to open the first flow path. When the first flow path disposed downstream of the exhaust gas inlet is opened, the exhaust gas flows linearly through the first flow path. A thermoelectric generator is disposed in the first flow path, and generates power based on the temperature difference between the heat of the exhaust gas and the heat of the medium flowing inside. The exhaust heat recovery device that can warm the cooling water and generate electric power is compact because the heat exchanger and the thermoelectric power generation device are arranged in parallel. That is, it is possible to provide an exhaust heat recovery device that can warm the cooling water and generate power while being compact.

  In the invention according to claim 2, the first flow path is arranged in the vertical direction and along the engine so that the exhaust gas flows in the vertical direction. By disposing it close to the engine, high-temperature exhaust gas can be introduced. Thereby, heat exchange and electric power generation can be performed efficiently. Moreover, the exhaust heat recovery device can be compactly disposed on the periphery of the engine by being disposed in the vertical direction. That is, heat exchange and power generation can be efficiently performed while being an exhaust heat recovery device that can be arranged in a compact manner.

1 is a front view of an exhaust heat recovery apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view of the exhaust heat recovery apparatus shown in FIG. 1. It is sectional drawing of the waste heat recovery apparatus shown by FIG. FIG. 4 is an enlarged view of part 4 of FIG. 3. It is a figure explaining an effect | action of the waste heat recovery apparatus shown by FIG. It is a figure explaining the basic composition of the conventional technology.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<Example>

  Please refer to FIG. The exhaust heat recovery device 20 is disposed vertically along the rear surface of the engine En. The engine En has a discharge port for discharging exhaust gas generated inside to the outside of the engine En, and one end of the connection pipe 11 is connected to the discharge port. The connecting pipe 11 extends from the exhaust port of the engine En to the exhaust heat recovery device 20. That is, the exhaust heat recovery device 20 is connected to the engine En via the connection pipe 11.

  Please refer to FIG. 2 and FIG. The exhaust heat recovery apparatus 20 includes a branching section 30 that branches the introduced exhaust gas into two flow paths, a first flow path 22 connected to the branching section 30, and an exhaust gas provided in the first flow path 22. A thermoelectric generator 40 that generates power based on the temperature difference between the heat of the gas and the heat of the medium that flows inside, and an upstream end provided along the first flow path 22 are connected to the branch portion 30. A second flow path 24, a heat exchanger 60 provided in the second flow path 24 for warming water flowing therein by the heat of exhaust gas, and a thermoactuator connected to the heat exchanger 60 and operating according to the temperature of the water 26, a valve device 27 that can be operated by the thermoactuator 26 to open and close the first flow path 22, a merging portion 70 that houses the valve device 27 and the first flow path 22 and the second flow path 24 merge together, Have

  The branch portion 30 is formed in a box shape by providing two members having a substantially U-shaped cross section so as to face each other. The branch portion 30 includes an upstream branch member 31 disposed on the upstream side and a downstream branch member 32 connected to the upstream branch member 31. Here, the upstream side means the upstream side based on the flow of exhaust gas. The downstream side refers to the downstream side based on the exhaust gas flow. The same applies to the following.

  The upstream branch member 31 includes an exhaust gas inlet 31a to which the connection pipe 11 (see FIG. 1) is connected and into which exhaust gas is introduced.

  The downstream branching member 32 includes a first channel upstream insertion hole 32a into which an upstream end of the first channel 22 is inserted, and a second channel 24 into which an upstream end is inserted. 2 flow path upstream side insertion hole 32b.

  The first flow path 22 includes a thermoelectric generator 40 that constitutes an upstream end, a first flow path main body 22a that extends from the downstream end of the thermoelectric generator 40 to the vicinity of the junction 70, and A first flow path extending portion 22b extending from the downstream end of the first flow path main body portion 22a to the inside of the merging portion 70. The first flow path body 22a has a flow path that narrows toward the downstream.

  In the state shown in FIG. 3, the downstream end of the first flow path extension 22 b is closed by the valve device 27. That is, the downstream end of the first flow path extension 22 b is a seat for the valve device 27.

  The thermoelectric generator 40 includes a case 41, a pair of end plates 42 and 43 that close both ends of the case 41, and an exhaust gas passage 44 that is supported at both ends by the end plates 42 and 43 and through which exhaust gas passes. A medium path 45 that is provided inside the case 41 through a gap along the exhaust gas path 44 and through which the medium passes, a medium fin 46 provided in the medium path 45, and these exhaust gas paths 44. And a thermoelectric element 47 (Peltier element) that is arranged in a gap between the medium path 45 and generates electric power based on a temperature difference between the heat of the exhaust gas and the heat of the medium.

  The case 41 is formed by providing two members having a substantially U-shaped cross section so as to face each other. The case 41 includes an upstream case half 41a inserted into the first flow path upstream insertion hole 32a, and a downstream case half 41b overlaid on the upstream case half 41a. Both the upstream case half 41a and the downstream case half 41b are formed by deep drawing a metal plate material.

  The upstream end plate 42 is formed integrally with the upstream end of the upstream case half 41a. That is, the bottom of the deep-drawn plate material is the end plate 42 on the upstream side.

  The downstream end plate 43 connects the downstream end of the exhaust gas passage 44 and the downstream case half 41b.

  The exhaust gas path 44 includes a tube 44a formed in a flat tube shape, a plate-shaped separator 44b disposed inside the tube 44a, and exhaust gas fins 44c and 44c disposed on both surfaces of the separator 44b. And consist of

  A case 48 is disposed along the exhaust gas passage 44. A gap is formed between the exhaust gas passage 44 and the case 48. The upstream end of the exhaust gas passage 44 is connected to the case 48. On the other hand, the downstream end of the exhaust gas passage 44 is not connected to the case 48 but is connected to the downstream end plate 43.

  A low temperature medium flows on the outer periphery of the case 48. Hot exhaust gas flows through the inner periphery of the exhaust gas passage 44 provided inside the case 48. The exhaust gas passage 44 differs in the amount of thermal expansion due to the temperature difference. The downstream end plate 43 is configured to be able to absorb the thermal elongation, and the load that can be applied to the case 41 and the like is reduced by absorbing the thermal elongation.

  The second flow path 24 is inserted into the second flow path upstream side insertion hole 32b and extends to the heat exchanger 60, the upstream second flow path 24a, the heat exchanger 60, and the junction 70 from the heat exchanger 60. A downstream second flow path 24b extending to the bottom.

  The heat exchanger 60 is a well-known device in which a plurality of heat exchange tubes 62 are stacked inside a core case 61, exhaust gas flows inside the heat exchange tube 62, and cooling water flows outside the heat exchange tube 62. It is. The heat of the exhaust gas is transmitted to the cooling water through the heat exchange tube 62.

  Please refer to FIG. The cooling water is guided into the thermoelectric generator 40 by a cooling water introduction pipe 63 connected to the case 41. The cooling water that has passed through the inside of the case 41 passes through the connecting pipe 66 and is guided into the heat exchanger 60. The cooling water warmed inside the core case 61 is guided to the thermoactuator 26 from the first cooling water discharge pipe 64 connected to the core case 61. The cooling water that has flowed to the thermoactuator 26 is discharged from a second cooling water discharge pipe 65 that is connected to the thermoactuator 26.

  In the thermoactuator 26, the rod 26a advances and retreats depending on the temperature of the cooling water. The tip of the rod 26 a is connected to the link mechanism 29.

  Please refer to FIG. The valve device 27 includes a shaft member 27a connected to the thermoactuator 26 via a link mechanism 29, a first valve body 27b fixed to the shaft member 27a, and a second valve body 27c.

  Both ends of the shaft member 27a are fixed to the joining portion 70 so as to be rotatable. The shaft member 27 a rotates via the link mechanism 29 when the rod 26 a of the thermoactuator 26 advances and retreats. The shaft member 27a has a substantially D shape with reference to a cross section perpendicular to the axis.

  The first valve body 27 b is a valve body that can rotate together with the shaft member 27 a and can open and close the downstream end of the first flow path 22. The second valve body 27 c is a valve body that can rotate together with the shaft member 27 a and can open and close the downstream end of the second flow path 24. When the first valve body 27b closes the first flow path 22, the second valve body 27c opens the second flow path 24 when the first valve body 27b and the second valve body 27c are closed. The second valve body 27 c is attached to the shaft member 27 a so as to close the second flow path 24 when the body 27 b opens the first flow path 22.

  Both the first valve element 27b and the second valve element 27c are fastened together and fixed to the flat surface of the shaft member 27a. This is because the assembly operation is facilitated and the first valve body 27b and the second valve body 27c are easily positioned relative to each other. On the other hand, since the first valve body 27b and the second valve body 27c are manufactured separately, the degree of freedom in design can be increased with respect to each shape. That is, it is possible to attach the respective valve bodies 27b and 27c to accurate positions while ensuring a high degree of design freedom of the respective valve bodies 27b and 27c.

  The joining portion 70 is formed in a box shape by providing two members having a substantially U-shaped cross section facing each other. The junction 70 includes an upstream junction member 71 to which the first channel 22 and the second channel 24 are connected, and a downstream junction member 72 connected to the upstream junction member 71.

  The upstream side merging member 71 is vacated so as to communicate with the first flow path downstream insertion hole 71a opened for inserting the first flow path extension 22b and the downstream second flow path 24b. And a flow path downstream side hole 71b.

  The downstream side merging member 72 has an exhaust gas discharge port 72a that is vacated to discharge the exhaust gas to the outside.

  The operation of the exhaust heat recovery apparatus 20 having the above configuration will be described below.

  Please refer to FIG. Immediately after starting the engine En (see FIG. 1), the temperature of the cooling water is low. For this reason, exhaust gas is flowed to the heat exchanger 60 and the cooling water is warmed by the heat of the exhaust gas. For this reason, the valve device 27 closes the downstream end of the first flow path 22.

  The exhaust gas introduced from the exhaust gas inlet 31 a flows through the second flow path 24. The heat exchanger 60 constitutes a part of the second flow path 24. For this reason, the introduced exhaust gas passes through the heat exchanger 60.

  The exhaust gas introduced into the heat exchanger 60 passes through the heat exchange tube 62. The heat exchange tube 62 is warmed by the passage of the exhaust gas. On the other hand, cooling water is allowed to flow around the outer periphery of the heat exchange tube 62. The heat of the heated heat exchange tube 62 is transferred to the cooling water. This warms the cooling water.

  Please refer to FIG. When the cooling water is heated to a predetermined temperature, the volume of the wax filled in the thermoactuator 26 expands. Thereby, the rod 26a moves forward so as to be pushed out by the wax. As the rod 26a moves forward, the link mechanism 29 rotates the shaft member 27a.

  Please refer to FIG. As the shaft member 27a rotates, the second valve body 27c closes the second flow path 24, and the first valve body 27b opens the first flow path 22. Thereby, the exhaust gas flows through the first flow path 22.

  The upstream end of the first flow path 22 is constituted by a thermoelectric generator 40. For this reason, the exhaust gas is introduced into the thermoelectric generator 40. The introduced exhaust gas passes through the exhaust gas passage 44. The exhaust gas passage 44 is warmed by the heat of the exhaust gas and becomes high temperature. On the other hand, a medium having a temperature lower than that of the exhaust gas flows through the medium path 45. The case 48 is cooled by a low temperature medium.

  One end of the thermoelectric element 47 is in contact with the outer periphery of the exhaust gas path 44, and the other end is in contact with the outer periphery of the medium path 45. The exhaust gas path 44 is at a high temperature, and the medium path 45 is at a lower temperature than the exhaust gas path 44. The thermoelectric element 47 generates power based on these temperature differences.

  According to the present invention described above, the following effects can be obtained.

  The exhaust heat recovery device 20 that can warm the cooling water and can generate power is compact because the heat exchanger 60 and the thermoelectric power generation device 40 are arranged in parallel. That is, it is possible to provide the exhaust heat recovery device 20 that can warm the cooling water and generate power while being compact.

  Please refer to FIG. The first flow path 22 is arranged in the vertical direction and along the engine En so that the exhaust gas flows in the vertical direction. By disposing it close to the engine En, high-temperature exhaust gas can be introduced. Thereby, heat exchange and electric power generation can be performed efficiently. Moreover, the exhaust heat recovery apparatus 20 can be compactly arrange | positioned at the periphery of the engine En by arrange | positioning toward an up-down direction. That is, heat exchange and power generation can be efficiently performed while the exhaust heat recovery device 20 can be arranged compactly.

  The thermoelectric generator 40 and the heat exchanger 60 are connected by a connecting pipe 66 through which water flows. The number of parts can be reduced, the system can be simplified, and space can be saved as compared with the case where the water (medium) introduction part and the discharge part are individually formed in each device. In this case, the medium flowing in the heat exchanger 60 is water flowing in the thermoelectric generator 40.

  In addition, water is allowed to flow in the order of the thermoelectric generator 40, the connecting pipe 66, and the heat exchanger 60. The water before being heated by the heat exchanger 60 is passed through the thermoelectric generator 40. Thereby, the temperature difference of water and exhaust gas can be enlarged more. It is possible to operate the thermoelectric power generation device 40 that generates power according to the temperature difference more efficiently. On the other hand, by introducing water that has passed through the thermoelectric generator 40 and is slightly warmed into the heat exchanger 60, the water can be warmed more quickly.

  Although the exhaust heat recovery apparatus of the present invention is applied to a four-wheeled vehicle in the embodiment, it can be applied to all vehicles, and can also be applied to vehicles other than vehicles and uses other than vehicles.

  Further, the exhaust heat recovery apparatus of the present invention may be disposed in a space other than the vicinity of the engine (power unit) such as a space under the vehicle body.

  That is, the present invention is not limited to the examples as long as the effects and effects are exhibited.

  The exhaust heat recovery apparatus of the present invention is suitable for a four-wheeled vehicle.

DESCRIPTION OF SYMBOLS 20 ... Waste heat recovery apparatus 22 ... 1st flow path 24 ... 2nd flow path 26 ... Thermo actuator 27 ... Valve apparatus 30 ... Branch part 31a ... Exhaust gas inlet 40 ... Thermoelectric power generation device 60 ... Heat exchanger En ... Engine

Claims (2)

An exhaust gas introduction port through which exhaust gas generated in the engine is introduced, a branch part for branching the exhaust gas introduced from the exhaust gas introduction port into two flow paths, and an upstream end connected to the branch part A first flow path facing the exhaust gas inlet, a second flow path provided along the first flow path and having an upstream end connected to the branch section, and provided in the second flow path A heat exchanger that heats the water flowing inside by the heat of the exhaust gas, a thermoactuator that is connected to the heat exchanger and that operates according to the temperature of the water, and that can be opened and closed by the thermoactuator. A waste heat recovery device having a valve device,
The exhaust heat recovery apparatus according to claim 1, wherein the first flow path includes a thermoelectric power generation device that generates power based on a temperature difference between the heat of the exhaust gas and the heat of the medium flowing inside.   2. The exhaust heat recovery apparatus according to claim 1, wherein the first flow path is disposed vertically along the engine so that the exhaust gas flows in the vertical direction.

Images