JPH0679168U - Exhaust heat power generator - Google Patents

Abstract

(57) [Abstract] [Purpose] Cooling the low temperature part of the thermoelectric conversion element with engine cooling water to improve power generation efficiency. [Structure] Inside the exhaust pipe 5, a heat exchanger 2 made of metal or the like having good thermal conductivity is provided. The thermoelectric conversion element 1 is provided outside the exhaust pipe 5 where the heat exchanger 2 is provided. A water jacket 3 is provided outside the thermoelectric conversion element 1. Radiator 4 in this water jacket 3
The cooling water 6 for cooling the engine is introduced from. As a result, the high temperature side electrode 11 of the thermoelectric conversion element 1 is heated by the exhaust heat, and the low temperature side electrode 12 is cooled by the cooling water 6
Cooled by. [Effect] Since the low temperature part side electrode 12 is constantly cooled by the cooling water 6, the power generation efficiency is increased and the generated power is stabilized.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a power generator using exhaust heat of exhaust gas emitted from an internal combustion engine for an automobile, and particularly to a power generator using a thermoelectric conversion element utilizing the Seebeck effect. In order to raise the temperature, it relates to a device in which the cooling water for cooling the engine is introduced into the low temperature part.

[0002]

[Prior art]

 Generally, high-temperature exhaust gas is emitted into the atmosphere from an automobile engine (internal combustion engine) without being used. On the other hand, in recent automobiles, a large amount of electric power is consumed in air conditioners, audio equipment, various power devices, and the like. In order to respond to this, it is necessary to improve the capacity of the generator (alternator) and the capacity of the battery. However, there is a limit to how much capacity and capacity can be increased from the viewpoints of space restrictions and weight (mass) restrictions. Therefore, it is considered to install an auxiliary power supply device that uses exhaust heat from the engine.

As an auxiliary power supply device using this exhaust heat, a device using a thermoelectric conversion element based on the Seebeck effect as shown in FIG. 3 can be considered. As shown in Fig. 3, this material joins two kinds of materials A and B having different work functions, keeps the joint on one side in a high temperature (Th) state, and the joint on the other side at a low temperature (Tc). By maintaining the state, a voltage (V) is generated between the two and the current flows. As a power generation device using such a thermoelectric conversion element based on the Seebeck effect, for example, the technique described in JP-A-61-254082 is already known.

[0004]

[Problems to be solved by the device]

 By the way, the above-mentioned conventional ones are excellent in that the exhaust heat is introduced into the high temperature part side, but there is a problem in the treatment in the low temperature part side. That is, in the above-mentioned conventional one, a metal having a high heat transfer coefficient or a ceramic that radiates an infrared ray is used on the side of the exhaust pipe forming the high temperature part to improve the efficiency of heat propagation on the side of the high temperature part. There is. However, the low temperature side only considers cooling due to the driving wind of automobiles. Therefore, there is a problem that the low temperature portion is not sufficiently formed unless the automobile is driven. In particular, the present thermoelectric conversion element increases the electromotive force (electromotive force) in proportion to the temperature difference (Th-Tc) between the high temperature portion and the low temperature portion. Therefore, it is necessary to consider the cooling of the low temperature part as well as the heat absorption efficiency of the high temperature part. In consideration of these matters, it is generally difficult to take a large space between the high temperature part and the low temperature part of the heat conversion element. The heat is also propagated to the low temperature side, and after a certain amount of time, the temperature difference (Th-Tc) becomes small. That is, the conventional one has a problem that even if a predetermined electromotive force (power generation) is obtained at the time of startup, the power generation is reduced after a certain amount of time has elapsed. In addition, power generation is reduced even when the engine is idling when the vehicle is stopped. It is an object (problem) of the present invention to provide a power generator that utilizes exhaust heat to solve such problems.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention has taken the following measures. That is, a thermoelectric conversion element that converts the thermal energy of exhaust gas discharged from an automobile engine (internal combustion engine) into electric energy, and the exhaust gas that is discharged from the internal combustion engine are discharged to the thermoelectric conversion element. In a power generator that uses exhaust heat, which also has the role of transmitting heat, in the exhaust pipe, a heat exchanger for receiving the exhaust heat from the exhaust gas is provided, and the heat exchanger is present. However, a thermoelectric conversion element is provided around the exhaust pipe, and a high temperature portion of the thermoelectric conversion element is formed with this side.Furthermore, a water jacket is provided outside the thermoelectric conversion element, and inside the water jacket. The cooling water provided for cooling the internal combustion engine is introduced to form a low temperature portion of the thermoelectric conversion element by the cooling water. Was Rukoto.

[0006]

[Action]

 By adopting the above configuration, the present invention has the following effects. That is, in FIG. 2, when the engine (internal combustion engine) 7 is operated (started), high temperature exhaust gas of about 700 ° to 800 ° C. is discharged from the engine 7. Then, the high-temperature exhaust gas flows from the exhaust manifold 71 to the exhaust pipe 5, and is guided to the power generation device including the thermoelectric conversion element 1 and the like provided in the exhaust pipe 5. On the other hand, when the engine 7 starts operating, cooling water for engine cooling is operated from the radiator 4 via the water hose 41 by the operation of a water pump (not shown) driven by the engine 7. Supplied to the water jacket 3. As a result, the high temperature exhaust gas of 600 ° to 700 ° C. is supplied to the high temperature part of the present power generator, and the cooling water of 80 ° to 90 ° C. is supplied to the low temperature part.

Therefore, in the present invention, when the engine 7 starts operating, a temperature difference of 500 ° to 600 ° C. is always ensured between the high temperature portion and the low temperature portion of the thermoelectric conversion element 1. Become. That is, Th-Tc = 500 ° to 600 ° C. In particular, in the present invention, the low-temperature portion is formed by cooling water for cooling the engine, and is not cooled by running wind or the like unlike the conventional one. You will be able to freely choose the installation location. Therefore, it is possible to freely select the vicinity of the exhaust manifold 71 having the highest exhaust gas temperature, the vicinity of the place where the catalyst for purifying the exhaust gas is installed, or the like. This can improve the power generation efficiency.

[0008]

【Example】

 An embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 2, the configuration of the present embodiment is provided in the middle of the exhaust pipe 5 that discharges exhaust gas discharged from the engine 7, and uses the exhaust heat from the exhaust pipe 5 as a heat source for a high temperature part. Of the thermoelectric conversion element 1 and a water jacket 3 into which cooling water is introduced from a radiator 4 for cooling the low temperature part of the thermoelectric conversion element 1 and the like.

In such a basic structure, the specific structure of the portion where the thermoelectric conversion element 1 is provided is as shown in FIG. That is, inside the exhaust pipe 5, there is provided a heat exchanger 2 made of a metal having good thermal conductivity or a ceramic that radiates infrared rays. A diffuser 21 having a plurality of openings for diffusing the flowing exhaust gas in the circumferential direction is provided. An exhaust pipe wall 51 is provided outside the portion where the diffuser 21 is provided so that the high temperature exhaust gas diffused outward at the diffuser 21 comes into contact with the diffuser 21.

Further, the high temperature side electrode 11 of the thermoelectric conversion element 1 is provided in contact with the exhaust pipe wall 51. Therefore, in the thermoelectric conversion element 1 having such a high temperature portion side electrode 11 inside, the low temperature portion side electrode 12 is formed outside. A water jacket 3 is provided outside the low-temperature-side electrode 12 in contact with the low-temperature-side electrode 12. Inside the water jacket 3, a radiator 4 is used for cooling the engine via a water hose 41. The cooling water 6 is introduced.

The thermoelectric conversion element 1 installed between the high temperature side electrode 11 and the low temperature side electrode 12 is made of two kinds of materials having greatly different work functions, for example, lead and tellurium alloy. And is formed by a combination of a P-type semiconductor and an N-type semiconductor made of these alloys or the like. By installing a plurality of thermoelectric conversion elements 1 having such a configuration and connecting them in series or in parallel with an appropriate number of connecting wires 13 as shown in FIG. 1, electric power having a predetermined current and voltage can be obtained. It will be generated (withdrawn). Lead wires 19 for sending the electric power thus drawn to a battery (not shown) or the like are provided on the electrodes 11 and 12 at both ends. In addition, in such a configuration, the heat exchanger 2 may be formed of a honeycomb core made of fine ceramic or the like.

An operation mode of the present embodiment having such a configuration will be described. That is, in FIG. 2, when the engine (internal combustion engine) 7 starts operating, high temperature exhaust gas of about 700 ° to 800 ° C. is discharged from the engine 7. Then, the high-temperature exhaust gas flows from the exhaust manifold 71 to the exhaust pipe 5, and is guided to the power generator including the thermoelectric conversion element 1 and the like provided in the exhaust pipe 5. On the other hand, when the engine 7 starts operating, the cooling water 6 for engine cooling is generated from the radiator 4 via the water hose 41 by the operation of a water pump (not shown) driven by the engine 7. It is supplied to the water jacket 3 of the device. As a result, the hot exhaust gas of 600 ° to 700 ° C. is supplied to the high temperature portion of the power generating device, and the cooling water of 80 ° to 90 ° C. is supplied to the low temperature portion.

Therefore, in the present embodiment, when the engine 7 starts operating, a temperature difference of 500 ° to 600 ° C. is always secured between the high temperature portion and the low temperature portion of the thermoelectric conversion element 1. Become. That is, Th-Tc = 500 ° to 600 ° C. In particular, in this embodiment, since the above-mentioned low temperature portion is formed by the cooling action of the cooling water 6 for cooling the engine, unlike the case where cooling is performed by running wind or the like, a stable low temperature portion is always formed. Will be done. As a result, the installation location of the power generator can be selected anywhere. Therefore, it is possible to freely select the vicinity of the exhaust manifold 71 where the temperature of the exhaust gas is the highest, or the vicinity of the place where the catalyst for purifying the exhaust gas is installed, and it is possible to maintain a large temperature difference. That is, a large power generation capacity can be secured.

[0014]

[Effect of device]

 According to the present invention, a thermoelectric conversion element for converting exhaust gas emitted from an automobile engine (internal combustion engine) into heat energy, and exhaust gas emitted from the internal combustion engine, and heat energy stored in the thermoelectric conversion element. In a power generation device that uses exhaust heat and that also plays a role of transmitting heat, a heat exchanger for receiving exhaust heat from the exhaust gas is provided in the exhaust pipe, and the presence of the heat exchanger. The thermoelectric conversion element is provided around the exhaust pipe, the high temperature part of the thermoelectric conversion element is formed on this side, and the water jacket is provided outside the thermoelectric conversion element. A cooling water provided for cooling the internal combustion engine is introduced into the interior of the internal combustion engine to form a low temperature part of the thermoelectric conversion element. Therefore, unlike the conventional low temperature part, which is formed by running wind, etc., the temperature of the low temperature part can be kept constant, and stable power generation can be obtained. . Further, when the engine (internal combustion engine) starts to operate, the temperature difference of 500 ° to 600 ° C. can always be secured in the part of the thermoelectric conversion element, so that it is efficient and stable. It is now possible to obtain power generation. In addition, since the low temperature part is cooled with cooling water for engine cooling, the degree of freedom in installing the thermoelectric conversion element is increased, and it can be set freely in the engine room where high temperature can be obtained or in the vicinity of the place where the catalyzer is installed. You can now choose the installation location.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a specific configuration of a power generator according to the present invention.

FIG. 2 is an external view showing the overall configuration of the present invention.

FIG. 3 is an explanatory view showing an operating principle of a thermoelectric conversion element forming a main part of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermoelectric conversion element 11 Electrode (high temperature part side electrode) 12 Electrode (low temperature part side electrode) 13 Connection wire 19 Lead wire 2 Heat exchanger 21 Diffuser 3 Water jacket 4 Radiator 41 Water hose 5 Exhaust pipe 51 Exhaust pipe wall 6 Cooling water 7 Internal Combustion Engine (Engine) 71 Exhaust Manifold

Claims (1)

[Scope of utility model registration request] 1. A thermoelectric conversion element for converting the thermal energy of exhaust gas discharged from an automobile engine (internal combustion engine) into electric energy, and the exhaust gas discharged from the internal combustion engine as well as heat generated by the thermoelectric conversion element. In a power generation device using exhaust heat, which also includes an exhaust pipe that also plays a role of transmitting energy, a heat exchanger for receiving the transfer of exhaust heat from the exhaust gas is provided in the exhaust pipe, and Where there is, a thermoelectric conversion element is provided around the exhaust pipe, and a high temperature part of the thermoelectric conversion element is formed on this side, and a water jacket is provided outside the thermoelectric conversion element, and the inside of the water jacket is provided. A cooling water provided for cooling the internal combustion engine is introduced to the above, and a low temperature part of the thermoelectric conversion element is formed by these. An exhaust heat-utilizing power generator characterized by comprising: