JP2008274790A - Waste heat recovery device - Google Patents

Abstract

For example, while realizing a cooling water circulation circuit with a relatively simple configuration, electric energy is recovered from exhaust gas in a wide temperature range.
An exhaust heat recovery device (41) is an exhaust heat recovery device that recovers electrical energy from exhaust gas exhausted from a heat source, and a flow path (21) through which the exhaust gas passes includes heat insulation means ( 423), the flow paths are divided into a plurality of parallel flow paths. A plurality of thermoelectric conversion means (421, 422) are arranged corresponding to each of the plurality of divided flow paths. These thermoelectric conversion means have different operating temperature ranges, and convert the thermal energy of the exhaust gas, which is a temperature belonging to the operating temperature range, into electrical energy. Moreover, the cooling means (44) which cools the site | part different from the site | part exposed to exhaust gas among several thermoelectric conversion means is provided.
[Selection] Figure 1

Description

  The present invention relates to an exhaust heat recovery apparatus that includes a thermoelectric element and recovers electrical energy from exhaust gas in an exhaust pipe, for example.

  For example, a Bi-Te semiconductor element or a Pb-Te semiconductor element is known as a thermoelectric element that is provided in this type of exhaust heat recovery device and converts the thermal energy of exhaust gas into electrical energy. Each of these elements exhibits high conversion efficiency in a certain operating temperature range unique to the element.

  However, the temperature of the exhaust gas from the automobile engine varies greatly, for example, 200 to 700 ° C. depending on the operating conditions. If this temperature range is within the operating temperature range of the used thermoelectric element, there is no particular problem. However, when the temperature is outside the operating temperature range, the thermoelectric element does not operate or even if it operates, the efficiency is low. For example, if the exhaust gas is at a temperature lower than the operating temperature range, the heat recovery efficiency may be deteriorated. On the other hand, if the exhaust gas is at a temperature higher than the operating temperature range, the heat recovery efficiency is deteriorated in addition to the deterioration of the heat recovery efficiency. Durability may be deteriorated (that is, heat deterioration).

  In order to deal with such problems, for example, as disclosed in Patent Document 1 below, the exhaust pipe is branched into first and second flow paths, and the first exhaust gas flow path has high-temperature exhaust heat. An exhaust gas energy recovery device is proposed that is equipped with a recovery means and a temperature sensor, and that has a low-temperature exhaust heat recovery means and a temperature sensor in the second exhaust gas flow path, and has a valve that switches the flow path according to the exhaust gas temperature. Has been. According to this apparatus, it is possible to recover heat with high efficiency in a wide temperature range corresponding to the exhaust gas temperature (see Patent Document 1).

  However, in the technique disclosed in Patent Document 1, for example, the high-temperature exhaust heat recovery means and the low-temperature exhaust heat recovery means are arranged in separate exhaust gas passages, so that it is necessary to provide a heat pipe or a cooling water circulation circuit separately. May occur, and the configuration may be complicated and large.

Japanese Patent Application Laid-Open No. 5-195765

  The present invention has been made in view of the above-described problems, for example, and provides an exhaust heat recovery device that can cope with exhaust gas in a wide temperature range while realizing a cooling water circulation circuit with a relatively simple configuration. The task is to do.

(1)
The exhaust heat recovery apparatus according to the present invention solves the above problems,
An exhaust heat recovery device that recovers electrical energy from exhaust gas exhausted from a heat source,
A heat insulating means for dividing the flow path through which the exhaust gas passes, into a plurality of parallel flow paths;
Thermoelectric conversion means for converting the thermal energy of exhaust gas, which has different operating temperature ranges and that belongs to the operating temperature range, into electrical energy, corresponding to each of the plurality of divided flow paths A plurality of thermoelectric conversion means arranged as
Cooling means for cooling a portion different from the portion exposed to the exhaust gas among the plurality of thermoelectric conversion means.

  According to the exhaust heat recovery apparatus of the present invention, electrical energy is preferably recovered from exhaust gas discharged from a heat source such as an engine. First, the flow path for the energy exhaust gas to pass through is divided into a plurality of flow paths parallel to each other by a heat insulating means (for example, a plate-shaped heat insulating material). For example, it is divided into two flow paths for high temperature exhaust gas and low temperature exhaust gas. A plurality of thermoelectric conversion means are arranged corresponding to each of the plurality of divided flow paths. These thermoelectric conversion means have different operating temperature ranges. For example, when the operating temperature range of the thermoelectric conversion means disposed in the flow path for high-temperature exhaust gas is 400 to 700 ° C., the operating temperature range of the thermoelectric conversion means disposed in the flow path for low-temperature exhaust gas is 200. The one with ˜400 ° C. is used. And the heat energy of the exhaust gas which is the temperature which belongs to this operating temperature range from the heat source of the vehicle is converted into electric energy by the thermoelectric conversion means. In other words, it generates electricity. Here, as pointed out also in the background art above, when the thermoelectric conversion means is at a lower temperature than the operating temperature range, the heat recovery efficiency may be deteriorated, and on the other hand, when the thermoelectric conversion means is at a higher temperature than the operating temperature range. May deteriorate the heat durability. However, according to the exhaust heat recovery apparatus according to the present invention, since the plurality of thermoelectric conversion means are arranged corresponding to each of the plurality of divided flow paths, these flow paths are arranged according to the temperature of the exhaust gas. By selectively using these, the sum of the operating temperature ranges of each of the plurality of thermoelectric conversion means can be covered while avoiding deterioration in heat recovery efficiency and heat resistance durability. For example, if it is the said example, it will respond | correspond to 200-700 degreeC exhaust gas which is the sum total of 200-400 degreeC and 400-700 degreeC.

  In addition, the conversion of the thermoelectric energy is due to the Seebeck effect, and the greater the temperature difference in the thermoelectric conversion means, the greater the amount of converted electric energy. Therefore, in order to increase the temperature difference, a part different from the part exposed to the energy exhaust gas among the plurality of thermoelectric conversion means is cooled by the cooling means (for example, a cooling water circulation circuit, a heat pipe). The more spatially the parts to be cooled are scattered, the more complicated the structure of this cooling means. However, according to the exhaust heat recovery apparatus according to the present invention, the plurality of thermoelectric conversion means are arranged in each of the plurality of divided flow paths, and these flow paths are originally only one flow path. . That is, it can be said that the parts to be cooled are integrated in a very narrow area in spite of having a plurality of thermoelectric conversion means. Therefore, the cooling means can be arranged with a relatively simple configuration without being spatially scattered. For example, in one exhaust heat recovery device provided in the middle of the exhaust pipe, when the high-temperature stack and the low-temperature stack are arranged at a ratio of half around the exhaust pipe, the cooling means is 1 around the exhaust pipe. Just go around. Thereby, the structure of the cooling means is the same as that in the case of only one stack in the prior art.

  As described above, according to the exhaust heat recovery apparatus according to the present invention, it is possible to deal with exhaust gas in a wide temperature range while realizing a cooling means such as a cooling water circulation circuit with a relatively simple configuration. As a result, restrictions on the location of the exhaust heat recovery device due to the heat-resistant temperature of the thermoelectric conversion means are reduced, and the degree of freedom in layout is increased. For example, it can be freely arranged regardless of before and after the catalyst, and is very effective in practice.

(2)
In one aspect of the exhaust heat recovery apparatus according to the present invention,
Among the plurality of divided flow paths, at least one of the plurality of thermoelectric conversion means in which a low temperature one having a relatively low operating temperature range is disposed.
Adjustment means is further provided for adjusting the flow rate of the exhaust gas passing through the one flow path by adjusting the inlet area and the outlet area of the one flow path.

  According to this aspect, the adjustment means (for example, including the electromagnetically driven control valve and the control device) arranges the one flow path (that is, the low-temperature thermoelectric conversion means having a relatively low operating temperature range). The inlet area and the outlet area of the flow path) are adjusted to increase / decrease between fully closed and fully open, for example, and the flow rate of the exhaust gas passing through the one flow path is adjusted. This makes it possible to enhance the protection of the low-temperature thermoelectric conversion means having a relatively low operating temperature range and to prevent the heat recovery efficiency from deteriorating. Of course, such an adjusting means may further increase or decrease the inlet area and the outlet area of another flow path (specifically, the flow path in which the high-temperature thermoelectric conversion means is disposed).

(3)
In an aspect further comprising this adjusting means,
A temperature specifying means for specifying the temperature of the exhaust gas discharged;
The adjusting means is configured to prevent the exhaust gas having a temperature exceeding the upper limit of the relatively low operating temperature range from passing through the one flow path, based on at least the temperature of the specified exhaust gas. You may make it adjust increase / decrease in the entrance area and exit area of a road.

According to this aspect, first, the temperature of the exhaust gas discharged is specified (or monitored) by the temperature specifying means regularly or irregularly. The mode for specifying the exhaust gas temperature is not particularly limited. For example, the exhaust gas temperature may be directly specified by a temperature sensor provided in the exhaust pipe, or the engine load may be calculated from the accelerator opening or the engine speed. You may specify indirectly by doing. Based on at least the temperature of the exhaust gas thus specified, the inlet area and the outlet area of the one flow path are adjusted to increase or decrease. For example, if the temperature of the specified exhaust gas exceeds the upper limit value (including a slight margin) of the operating temperature range related to the low-temperature thermoelectric conversion means, this is not the temperature range that should be originally used. Since there is a possibility that the low-temperature thermoelectric conversion means cannot be heat-resistant, the adjusting means fully closes the inlet area of the one flow path. Thus, the high temperature exhaust gas does not need to pass through the one flow path. Also in this case, if the exhaust gas is passed through other high-temperature thermoelectric conversion means, a decrease in heat recovery efficiency can be suppressed.
(4)
Alternatively, in an aspect further comprising this adjusting means,
An electric energy amount specifying means for specifying the electric energy amount to be converted;
The adjusting means increases or decreases the inlet area and the outlet area of the one flow path based on at least the specified electric energy amount so that the specified electric energy amount relatively increases. May be.

  According to this aspect, the electric energy amount converted by the thermoelectric conversion means is specified (or monitored) for each thermoelectric conversion means or collectively by an electric energy amount specifying means such as an ammeter or a voltmeter. The inlet area and the outlet area of the one flow path are adjusted in a feedback manner by the adjusting means so that the specified electric energy amount relatively increases based at least on the specified electric energy amount. . For example, the amount of electrical energy specified before and after expanding the entrance area of the one flow path by a predetermined amount is compared. If the amount of electrical energy increases, it is further expanded, and if it decreases, the amount is decreased. As the amount of electrical energy increases, the inlet area is increased or decreased in a feedback manner. Then, even if the load situation (specifically specified from the rotation speed and throttle opening) changes or the temperature of the exhaust gas changes, the amount of electric energy recovered by the exhaust heat recovery device, that is, the amount of power generation Can be increased as much as possible.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings as the best mode for carrying out the invention.

(1) Configuration FIG. 1 is a schematic cross-sectional view of a vehicle 1 including an exhaust heat recovery device 41 according to an embodiment.

  In FIG. 1, the vehicle 1 includes an ECU 100, an engine 200, an exhaust pipe 21, an exhaust purification catalyst 222, and an exhaust heat recovery device 41.

  The ECU 100 is a specific example of the “adjustment unit” according to the present invention, and is configured to function as an electronic control unit that controls the entire operation of the vehicle 1. Specifically, the ECU 100 is configured as a logical operation circuit centered on a read-only memory (Read Only Memory: ROM) storing a control program and an occasional write-read memory (Random Access Memory: RAM) storing various data. Has been. And, various actuators including an input port for receiving an input signal relating to the temperature of exhaust gas, the temperature for specifying the load state, the converted electric energy amount, etc. from various sensors, and the upstream control valve 424 and the downstream control valve 425 Is electrically connected to an output port for sending control signals to

  The engine 200 is an internal combustion engine that outputs power by burning fuel such as gasoline, and the driving force generated by the engine 200 rotates a wheel (not shown). The engine 200 is subjected to operation control such as fuel injection control, ignition control, and intake air amount adjustment control by an ECU 100 that receives signals from various sensors that detect the operation state.

  The exhaust pipe 21 is connected to the port outlet of each cylinder of the engine 200 via an exhaust manifold, and is a pipe for discharging the exhaust gas generated by the combustion of the engine 200 to the outside. The exhaust pipe 21 includes an exhaust purification catalyst 222, an exhaust temperature sensor 223, and an exhaust heat recovery device 41.

  The exhaust purification catalyst 222 uses a so-called three-way catalyst, and purifies substances such as nitrogen oxides, carbon monoxide, and hydrocarbons contained in the exhaust gas. In FIG. 1, the exhaust heat recovery device 41 is disposed on the downstream side of the exhaust purification catalyst 222, but may be disposed on the upstream side of the exhaust purification catalyst 222.

  The exhaust temperature sensor 223 is a temperature sensor as one specific example of the “temperature specifying means” according to the present invention, and detects the temperature T of the exhaust gas flowing through the exhaust pipe 21 and transmits it to the ECU 100.

  The detailed configuration of the exhaust heat recovery apparatus 41 will be described with reference to FIGS. 4 and 5 in addition to FIG. Here, FIG. 4 is a perspective view of the exhaust heat recovery apparatus 41 according to the embodiment. FIG. 5 is a front view of the exhaust heat recovery apparatus 41 according to the embodiment.

  As shown in FIGS. 4 and 5 in addition to FIG. 1, the exhaust heat recovery apparatus 41 includes a high temperature stack 421, a low temperature stack 422, a band fixing unit 3, a heat pipe 44, a heat insulating material 423, and an upstream control valve 424. , And a downstream control valve 425. The exhaust heat recovery device 41 is provided with flanges (not shown) for connecting to the exhaust pipe 210 at the most upstream part and the most downstream part, respectively, in the middle of the exhaust pipe 21 (for example, directly below the exhaust manifold, exhaust gas It is disposed downstream of the purification catalyst 222, upstream of the muffler, and the like. The exhaust heat recovery device 41 converts thermal energy into electrical energy by a stack in an operating temperature range corresponding to the temperature of the exhaust gas, and charges the battery 63 via the DC / DC converter 61.

  The high-temperature stack 421 is a specific example of the “thermoelectric conversion means” according to the present invention, and a plurality of high-temperature stacks 421 are disposed, for example, every 60 ° in the circumferential direction of the exhaust heat recovery device 41 and adjacent to the exhaust gas flow direction. A plurality of them are arranged. The high temperature stack 421 includes the heat exchange fins 10 a, the thermoelectric conversion module 11 a, and the cooling unit 12.

  The heat exchange fin 10a is formed of a material having excellent heat conductivity and is provided so as to protrude into the exhaust gas flow path, and is efficient when the exhaust gas flowing through the exhaust pipe 21 is in a relatively high temperature state. Perform heat recovery.

The thermoelectric conversion module 11a has a substantially square shape with a small area, for example, and has a predetermined operation due to the Seebeck effect corresponding to the temperature difference between the high-temperature end surface in contact with the heat exchange fin 10a and the low-temperature end surface in contact with the cooling unit 12 Thermal energy is converted into electrical energy in the temperature range, and the electrical energy is output from two electrodes (not shown) to the battery 63. For this purpose, the thermoelectric conversion module 11a includes a plurality of thermoelectric elements (for example, two types of p-type and n-type semiconductors made of Bi ₂ Te ₃ or the like) (not shown). It is arranged in series and thermally in parallel.

  The cooling unit 12 is disposed on the outer peripheral side of the thermoelectric conversion module 11a and is in close contact with the low temperature end surface of the thermoelectric conversion module 11a. The cooling unit 12 cools the low-temperature end surface of the thermoelectric conversion module 11a by moving the heat that has passed through the thermoelectric conversion module 11a to the heat radiating unit (not shown) using the heat pipe 44. The cooling unit 12 is, for example, a rectangular parallelepiped having a lower surface and an upper surface having the same shape as the low temperature end surface of the thermoelectric conversion module 11a and a predetermined height, and has a divided structure including an upper divided portion 52a and a lower divided portion 52b. (See FIG. 5). Each divided portion is formed of a material having excellent thermal conductivity, and each of the divided surfaces is provided with a semi-cylindrical concave portion orthogonal to the direction in which the exhaust gas flows, and the upper and lower concave portions are combined to form a circle. Columnar holes are formed. The diameter of the cylindrical hole is a diameter with which the heat pipe 44 is fitted, and the heat pipe 44 is fixed to the hole. The lower surface of the lower divided portion 52b is a horizontal surface so as to be in close contact with the low temperature end surface of the thermoelectric conversion module 11a.

  The low temperature stack 422 is also a specific example of the “thermoelectric conversion means” according to the present invention, and basically has the same configuration as the high temperature stack 421, but the temperature characteristics of the heat exchange fins 10b and the thermoelectric conversion module 11b. Is different. In other words, the heat exchange fin 10b has a capability of efficiently recovering heat when the temperature of the exhaust gas is lower than the temperature of the exhaust gas at which heat recovery is efficiently performed by the high temperature stack 421. . For example, when stainless steel is used as the material for the heat exchange fins 10a of the high temperature stack 421, aluminum may be used for the heat exchange fins 10b of the low temperature stack 422. The thermoelectric conversion module 11b has an operating temperature region on a lower temperature side than that used in the high temperature stack 421. For example, when the operating temperature range of the high temperature stack 421 is 400 to 700 ° C., a material is used such that the operating temperature range of the low temperature stack 422 is 200 to 400 ° C.

  The band fixing unit 3 includes a band 13, six pressing members 14, bolts 15, nuts 16, and buffer members 17. The band fixing unit 3 applies a predetermined pressure from the outside of the six cooling units 12 in each row, fixes the six thermoelectric conversion modules 11 between the cooling unit 12 and the heat exchange fins 10, and the entire apparatus. (See FIG. 4).

  The heat pipe 44 is a specific example of the “cooling unit” according to the present invention, and one end portion thereof is accommodated in each hole formed in the six cooling units 12 arranged along the circumferential direction. Further, it is bent into a hexagonal shape (see FIG. 5), and each cooling unit 12 is cooled. The other end extends to a heat radiating part such as a radiator in order to radiate the heat received when cooling the cooling part 12. Since one heat pipe 44 is housed and fixed in each hole of the six cooling units 12,... In each row, it is arranged in a direction orthogonal to the direction in which the exhaust gas flows. As shown in FIG. 4, four such heat pipes 44 are arranged along the direction in which the exhaust gas flows. The exhaust gas recovers thermal energy as it goes downstream, and the temperature of the exhaust gas decreases. Therefore, it is preferable that the amount of heat transported in the four heat pipes 44 is higher in the upstream.

  Returning to FIG. 1 again, the heat insulating material 423 is a specific example of the “heat insulating means” according to the present invention, and the exhaust gas flow path in the exhaust heat recovery apparatus 41 is divided into the high temperature stack 421 side and the low temperature stack 422. Divide into two parts. As a result, when the high-temperature exhaust gas flows only in the high-temperature stack 421 side in the two divided channels, the heat hardly needs to be transmitted to the low-temperature stack 422. Note that the number of divisions may be two or more.

  The upstream control valve 424 and the downstream control valve 425 are specific examples of the “adjusting means” according to the present invention, and are, for example, butterfly valves. The opening degree can be adjusted in a stepless manner from fully closed to fully open by the actuator, whereby the exhaust gas flowing into the exhaust heat recovery device 41 is flown in any one of the flow paths divided by the heat insulating material 423. You can select how much to flow. From this point of view, at least the upstream control valve 424 may be provided. These control valves may be placed independently in each of the divided flow paths, or subordinately (ie, opening one flow path will close the other flow path). May be.

(2) Operation Next, in addition to FIG. 1, the basic operation will be described with reference to FIG. 2, FIG. 3, and FIG. FIG. 2 is a schematic cross-sectional view of the vehicle 1 including the exhaust heat recovery apparatus 41 according to the embodiment (the entrance / exit of the flow path on the high temperature stack 421 side: fully closed). FIG. 3 is a schematic cross-sectional view of the vehicle 1 including the exhaust heat recovery apparatus 41 according to the embodiment (entrance / exit of the flow path on the low temperature stack 422 side: fully closed). FIG. 6 is a flowchart showing a basic operation of the exhaust heat recovery apparatus 41 according to the embodiment.

As shown in the flowchart of FIG. 6, during the operation of the vehicle 1, first, the exhaust temperature sensor 223 specifies the temperature T of the exhaust gas flowing through the exhaust pipe 21 (step S1). Based on the identified exhaust gas temperature T, ECU 100 determines whether or not “exhaust gas temperature T ≦ upper limit value T _lmax of the operating temperature range of low temperature stack 422” (step S2). Here, if it is determined that “the temperature T of the exhaust gas T ≦ the upper limit value T _lmax of the operating temperature range of the low temperature stack 422” (step S2: YES), that is, if the exhaust gas is relatively low temperature, Even if the exhaust gas passes through the low-temperature stack 422, it is not assumed that the low-temperature stack 422 does not operate, or even if operated, the efficiency is low, or the heat deteriorates. Therefore, the ECU 100 opens the upstream control valve 424 and the downstream control valve 425 so that the exhaust gas also passes through the low temperature stack 422, that is, the inlet / outlet of the flow path on the low temperature stack 422 side is fully opened. Set the degree. At this time, even if the temperature T of the exhaust gas deviates from the operating temperature range of the high temperature stack 421, the problem of heat resistance hardly occurs because it is lower than the assumed temperature. Therefore, the entrance / exit of the flow path on the high temperature stack 421 side may be fully opened (see FIG. 1) from the viewpoint of reducing exhaust resistance. Alternatively, it may be fully closed (see FIG. 2) from the viewpoint of deviating from the operating temperature range (step S3). On the other hand, if it is not determined that “the temperature T of the exhaust gas T ≦ the upper limit value T _lmax of the operating temperature range of the low temperature stack 422” (step S2: NO), that is, if the exhaust gas is relatively hot, the exhaust gas However, if the low temperature stack 422 passes through the flow path on the low temperature stack 422 side, the low temperature stack 422 may not operate, or may be operated at low efficiency, or may be thermally deteriorated. Therefore, the ECU 100 connects the upstream side control valve 424 and the downstream side so that the high temperature exhaust gas does not pass through the flow path on the low temperature stack 422 side, that is, the entrance / exit of the flow path on the low temperature stack 422 side is fully closed. The opening degree of the side control valve 425 is set (see FIG. 3) (step S4). Since such processing is performed regularly or irregularly, it is possible to generate power while avoiding exposing the low temperature stack 422 to unexpected high temperature exhaust gas.

  Alternatively, the exhaust heat recovery device 41 may be operated as shown in the flowchart of FIG. 7 instead of FIG.

  FIG. 7 is a flowchart showing another operation of the exhaust heat recovery apparatus 41 according to the embodiment.

  As shown in the flowchart of FIG. 7, during the operation of the vehicle 1, the following processing is repeatedly performed in a feedback manner. First, an ammeter 62 provided in a line connecting the exhaust heat recovery device 41 and a battery (not shown), which is a specific example of the “electric energy amount specifying means” according to the present invention, or attached to the battery 63. The amount of electrical energy converted by the exhaust heat recovery device 41 is specified by a SCO sensor (not shown). The ECU 100 records this value (step S21). Subsequently, the amount of electric energy is compared between the current process and the previous process (that is, the previous process among the loop processes repeatedly performed) (step S22). Here, when the current value of the electric energy amount is equal to or greater than the previous value (step S22: YES), the opening settings of the upstream side control valve 424 and the downstream side control valve 425 performed in the previous process are set according to the thermoelectric conversion efficiency. Since it can be said that it is appropriate from the viewpoint, the opening of each control valve is set in the same manner as the previous time (step S23). For example, in the previous process, if the inlet / outlet of the flow path on the low temperature stack 422 side is closed by a predetermined opening, the opening is further closed by a predetermined opening in the same manner. On the other hand, if the current value of the electric energy amount is not equal to or greater than the previous value (step S22: NO), the previous opening degree setting is appropriate due to the low temperature stack 422 being exposed to the high temperature exhaust gas. In this case, the current direction is set in the opposite direction (step S24). For example, in the previous process, if the inlet / outlet of the flow path on the low temperature stack 422 side is closed by a predetermined opening degree, this time, the opening is reversed. In this way, since the inlet area and outlet area of the flow path are adjusted to increase or decrease in a feedback manner, the exhaust heat recovery device recovers even if the load status of the vehicle 1 changes or the temperature of the exhaust gas changes. The amount of electrical energy to be generated, that is, the amount of power generation can be increased as much as possible.

  According to the embodiment described above, since the high-temperature stack 421 and the low-temperature stack 422 are included in one exhaust heat recovery device 41, the heat pipe 44 is almost the same as the case where there is only one stack. A simple configuration is sufficient. In addition, the high temperature stack 421 and the low temperature stack 422 can cope with a wide range of exhaust gas temperatures while protecting the low temperature stack 422 from the high temperature exhaust gas, which is very effective in practice.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and exhaust heat recovery accompanying such a change is possible. The apparatus is also included in the technical scope of the present invention.

It is a typical sectional view of vehicles 1 provided with exhaust heat recovery device 41 concerning an embodiment. It is a typical sectional view of vehicles 1 provided with exhaust heat recovery device 41 concerning an embodiment (entrance of a channel by the side of high temperature stack 421: fully closed). It is a typical sectional view of vehicles 1 provided with exhaust heat recovery device 41 concerning an embodiment (entrance of a channel by the side of low temperature stack 422: fully closed). It is a perspective view of waste heat recovery equipment 41 concerning an embodiment. It is a front view of waste heat recovery equipment 41 concerning an embodiment. It is a flowchart which shows the basic operation | movement of the waste heat recovery apparatus 41 which concerns on embodiment. It is a flowchart which shows other operation | movement of the waste heat recovery apparatus 41 which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 100 ... ECU, 200 ... Engine, 21 ... Exhaust pipe, 222 ... Exhaust purification catalyst, 41 ... Exhaust heat recovery device, 421 ... High temperature stack, 422 ... Low temperature stack, 3 ... Band fixing part, 44 ... Heat pipe, 423 ... heat insulating material, 424 ... upstream control valve, 425 ... downstream control valve, 61 ... DC / DC converter, 63 ... battery

Claims (4)

An exhaust heat recovery device that recovers electrical energy from exhaust gas exhausted from a heat source,
A heat insulating means for dividing the flow path through which the exhaust gas passes, into a plurality of parallel flow paths;
Thermoelectric conversion means for converting the thermal energy of exhaust gas, which has different operating temperature ranges and that belongs to the operating temperature range, into electrical energy, corresponding to each of the plurality of divided flow paths A plurality of thermoelectric conversion means arranged as
An exhaust heat recovery apparatus comprising: cooling means for cooling a portion different from the portion exposed to the exhaust gas among the plurality of thermoelectric conversion means. Among the plurality of divided flow paths, at least one of the plurality of thermoelectric conversion means in which a low temperature one having a relatively low operating temperature range is disposed.
The exhaust gas according to claim 1, further comprising adjusting means for adjusting the flow rate of the exhaust gas passing through the one flow path by increasing or decreasing the inlet area and the outlet area of the one flow path. Heat recovery device. A temperature specifying means for specifying the temperature of the exhaust gas discharged;
The adjusting means is configured to prevent the exhaust gas having a temperature exceeding the upper limit of the relatively low operating temperature range from passing through the one flow path, based on at least the temperature of the specified exhaust gas. The exhaust heat recovery apparatus according to claim 2, wherein the entrance area and the exit area of the road are adjusted to increase or decrease. An electric energy amount specifying means for specifying the electric energy amount to be converted;
The adjusting means increases or decreases the inlet area and the outlet area of the one flow path based on at least the specified electric energy amount so that the specified electric energy amount relatively increases. The exhaust heat recovery apparatus according to claim 2, wherein

Images