JP6150676B2 - Power generation system - Google Patents

Description

  The present invention relates to a power generation system, and more particularly to a power generation system mounted on a vehicle such as an automobile.

  Conventionally, in internal combustion engines such as automobile engines, heat exchangers such as boilers and air conditioning equipment, electric engines such as generators and motors, and various energy utilization devices such as light emitting devices such as lighting, for example, as exhaust heat, light, etc. A lot of thermal energy is released and lost.

  In recent years, from the viewpoint of energy saving, it has been required to recover the released thermal energy and reuse it as an energy source. As such a system, specifically, for example, a heat source whose temperature rises and falls over time, and a first device that is electrically polarized by a piezo effect, a pyroelectric effect, a Seebeck effect, or the like according to a temperature change of the heat source ( In order to take out electric power from a 1st device, a power generation system provided with the 2nd device (electrode etc.) arranged so that the 1st device may be pinched is proposed (for example, refer to patent documents 1). .)

JP 2011-250675 A

  On the other hand, in the power generation system described in Patent Document 1, it is desired to generate power more efficiently.

  An object of the present invention is to provide a power generation system capable of generating power with excellent efficiency by a simple method.

  In order to achieve the above object, a power generation system according to the present invention includes a heat source whose temperature rises and falls over time, a first device whose temperature rises and falls over time due to a temperature change of the heat source, and the first device. A second device for extracting power from the power source, a detecting means for detecting the temperature of the first device, a voltage applying means for applying a voltage to the first device, and the detecting means to raise the temperature of the first device. And a control means for operating the voltage application means when detected, and stopping the voltage application means when a temperature drop of the first device is detected.

  In the power generation system of the present invention, when the temperature rise of the first device is detected, the voltage applying means is activated and a voltage is applied to the first device. On the other hand, when the temperature drop of the first device is detected, the voltage application unit is stopped and the application of the voltage is stopped.

  According to such a power generation system, energy can be efficiently extracted from the first device by a relatively simple method of operating or stopping the voltage application unit, and power generation efficiency can be improved.

It is a schematic structure figure showing one embodiment of the power generation system of the present invention. It is a schematic block diagram which shows one Embodiment by which the electric power generation system of this invention was mounted. It is a principal part enlarged view of the electric power generation system shown in FIG. 4 is a graph showing a relationship between an applied voltage and a temperature change in Example 1. It is a graph which shows the relationship between the applied voltage in Example 1, a temperature change, and a generated voltage.

  FIG. 1 is a schematic configuration diagram showing an embodiment of a power generation system of the present invention.

  In FIG. 1, a power generation system 1 includes a heat source 2 whose temperature rises and falls over time, a first device 3 whose temperature rises and falls over time due to a temperature change of the heat source 2, and electric power from the first device 3. A second device 4 for taking out, a temperature sensor 8 as a detecting means for detecting the temperature of the first device 3, a voltage applying device 9 as a voltage applying means for applying a voltage to the first device 3, and a temperature sensor 8 The control unit as a control means for operating the voltage application device 9 when the temperature rise of the first device 3 is detected by the, and stopping the voltage application device 9 when the temperature drop of the first device 3 is detected. 10.

  The heat source 2 is not particularly limited as long as the temperature rises and falls over time, and examples thereof include various energy utilization devices such as an internal combustion engine and a light emitting device.

  An internal combustion engine is a device that outputs power, for example, for a vehicle. For example, a single cylinder type or a multi-cylinder type is adopted, and a multi-cycle type (for example, a 2-cycle type, a 4-cycle type) is used in each cylinder. System, 6-cycle system, etc.) are employed.

  In such an internal combustion engine, pistons are repeatedly moved up and down in each cylinder. For example, in a 4-cycle system, an intake process, a compression process, an explosion process, an exhaust process, and the like are sequentially performed, and fuel is discharged. It is burned and power is output.

  In such an internal combustion engine, in the exhaust process, high-temperature exhaust gas is exhausted through an exhaust gas pipe, heat energy is transmitted using the exhaust gas as a heat medium, and the internal temperature of the exhaust gas pipe rises.

  On the other hand, in the other steps (steps excluding the exhaust step), the amount of exhaust gas in the exhaust gas pipe is reduced, so that the internal temperature of the exhaust gas pipe decreases compared to the exhaust process.

  As described above, the temperature of the internal combustion engine rises in the exhaust process and falls in the intake process, the compression process, and the explosion process, that is, rises and falls over time.

  In particular, since each of the above steps is periodically and sequentially repeated according to the piston cycle, the inside of the exhaust gas pipe of each cylinder in the internal combustion engine is periodically cycled with the repetition cycle of each of the above steps. A temperature change, more specifically, a high temperature state and a low temperature state are periodically repeated.

  When the light emitting device is turned on (emission light), for example, light such as infrared rays and visible light is used as a heat medium, and the temperature rises due to the heat energy. Therefore, the temperature of the light emitting device increases and decreases over time by turning on (emitting) and turning off over time.

  In particular, for example, when the light-emitting device is a light-emitting device (blinking (flashing) type light-emitting device) in which lighting is turned on and off intermittently over time, the light-emitting device is turned on (light-emitting). Due to the thermal energy of the light, a temperature change periodically, more specifically, a high temperature state and a low temperature state are periodically repeated.

  Moreover, as the heat source 2, for example, a plurality of heat sources can be provided, and a temperature change can be caused by switching between the plurality of heat sources.

  More specifically, for example, two heat sources, a low-temperature heat source (such as a coolant) and a high-temperature heat source (eg, a heating material) having a higher temperature than the low-temperature heat source, are prepared as the heat source. A mode in which a low-temperature heat source and a high-temperature heat source are alternately switched is used.

  Thereby, the temperature as a heat source can be raised or lowered with time, and in particular, the temperature can be periodically changed by periodically switching the low-temperature heat source and the high-temperature heat source.

  Although it does not restrict | limit especially as the heat source 2 provided with the several heat source which can be switched, For example, the high temperature air provided with the low temperature air supply system for combustion, the thermal storage heat exchanger, the high temperature gas exhaust system, and the supply / exhaust switching valve Combustion furnace (for example, a high-temperature gas generator described in Republished No. 96-5474), for example, a seawater exchange device (hydrogen storage alloy actuator-type seawater exchange device) using a high-temperature heat source, a low-temperature heat source, and a hydrogen storage alloy Is mentioned.

  As these heat sources 2, the said heat source can be used individually or in combination with 2 or more types.

  The heat source 2 is preferably a heat source whose temperature changes periodically with time.

  The heat source 2 is preferably an internal combustion engine.

  The first device 3 is a device that is electrically polarized in accordance with a temperature change of the heat source 2.

  The electric polarization referred to here is a phenomenon in which a potential difference occurs due to dielectric polarization due to displacement of positive and negative ions due to crystal distortion, such as a piezo effect and / or a phenomenon in which a dielectric constant changes due to a temperature change and a potential difference occurs, such as pyroelectricity. It is defined as a phenomenon in which an electromotive force is generated in a material, such as an effect.

  More specifically, examples of the first device 3 include a device that is electrically polarized by a piezo effect, a device that is electrically polarized by a pyroelectric effect, and the like.

  The piezo effect is an effect (phenomenon) in which when a stress or strain is applied, it is electrically polarized according to the magnitude of the stress or strain.

  The first device 3 that is electrically polarized by the piezo effect is not particularly limited, and a known piezo element (piezoelectric element) can be used.

  When a piezo element is used as the first device 3, the piezo element is in contact with the heat source 2 in a state where the periphery is fixed by a fixing member and volume expansion is suppressed, or It arrange | positions so that it may contact (exposure) to the heat medium (exhaust gas mentioned above, light, etc.) which transfers heat.

  The fixing member is not particularly limited, and for example, a second device 4 (for example, an electrode) described later can be used.

  In such a case, the piezo element is heated or cooled (possibly via a heat medium (exhaust gas, light, etc.) as described above) due to a change in temperature of the heat source 2 with time, thereby expanding. Or shrink.

  At this time, since the volume expansion of the piezo element is suppressed by the fixing member, the piezo element is pressed by the fixing member and is electrically polarized by the piezo effect (piezoelectric effect) or phase transformation near the Curie point. . Thereby, as will be described in detail later, power is extracted from the piezo element via the second device 4.

  In addition, such a piezo element is normally maintained in a heated state or a cooled state, and when its temperature becomes constant (that is, a constant volume), the electric polarization is neutralized, and then cooled or heated, Again, it is electrically polarized.

  Therefore, as described above, when the temperature of the heat source 2 periodically changes and the high temperature state and the low temperature state are periodically repeated, the piezo element is periodically heated and cooled. Electrical polarization and its neutralization are repeated periodically.

  As a result, electric power is extracted as a waveform (for example, alternating current, pulsating flow, etc.) that fluctuates periodically by the second device 4 described later.

  The pyroelectric effect is, for example, an effect (phenomenon) in which the insulator is electrically polarized in accordance with a change in temperature when the insulator (dielectric) is heated and cooled, and includes the first effect and the second effect. It is out.

  The first effect is an effect in which, when the insulator is heated and cooled, it spontaneously polarizes due to the temperature change and generates a charge on the surface of the insulator.

  In addition, the second effect is an effect that pressure deformation occurs in the crystal structure due to temperature changes during heating and cooling of the insulator, and piezoelectric polarization occurs due to stress or strain applied to the crystal structure (piezo effect, piezoelectric effect). ).

  The device that is electrically polarized by such a pyroelectric effect is not particularly limited, and a known pyroelectric element can be used.

  When a pyroelectric element is used as the first device 3, the pyroelectric element is in contact with the heat source 2 or in contact with a heat medium (exhaust gas, light, or the like described above) that transmits the heat of the heat source 2 ( To be exposed).

  In such a case, the pyroelectric element is heated or cooled (possibly via a heat medium (exhaust gas, light, etc.) described above) due to a change in temperature of the heat source 2 with time, and the pyroelectric effect (first The electric polarization is caused by the first effect and the second effect. Thereby, although mentioned later in detail, electric power is taken out from the pyroelectric element via the second device 4.

  Also, such pyroelectric elements are usually maintained in a heated state or a cooled state, and when the temperature becomes constant, the electric polarization is neutralized, and then cooled or heated again to be electrically polarized again. .

  Therefore, when the temperature of the heat source 2 is periodically changed as described above and the high temperature state and the low temperature state are periodically repeated, the pyroelectric element is periodically heated and cooled. The electrical polarization of the element and its neutralization are repeated periodically.

  As a result, electric power is extracted as a waveform (for example, alternating current, pulsating flow, etc.) that fluctuates periodically by the second device 4 described later.

  These first devices 3 can be used alone or in combination of two or more.

Specifically, as described above, the first device 3 is a known pyroelectric element (for example, BaTiO ₃ , CaTiO ₃ , (CaBi) TiO ₃ , BaNd ₂ Ti ₅ O ₁₄ , BaSm ₂ Ti _4. O ₁₂ , lead zirconate titanate (PZT: Pb (Zr, Ti) O ₃ ), etc., known piezo elements (eg, quartz (SiO ₂ ), zinc oxide (ZnO), Rochelle salt (potassium sodium tartrate) _{(KNaC 4 H 4 O 6)} , lead zirconate titanate (PZT: Pb (Zr, Ti ) O 3), lithium niobate (LiNbO _3), lithium tantalate (LiTaO _3), lithium tetraborate _(Li 2 B ₄ O ₇ ), Langasite (La ₃ Ga ₅ SiO ₁₄ ), Aluminum Nitride (AlN), Tourmaline, Poly Vinylidene fluoride (PVDF), etc.), Ca ₃ (VO ₄ ) ₂ , Ca ₃ (VO ₄ ) ₂ / Ni, LiNbO ₃ , LiNbO ₃ / Ni, LiTaO ₃ , LiTaO ₃ / Ni, Li (Nb _0.4 Ta _0.6 ) O ₃ , Li (Nb _0.4 Ta _0.6 ) O ₃ / Ni, Ca ₃ {(Nb, Ta) O ₄ } ₂ , Ca ₃ {(Nb, Ta) O ₄ } ₂ / Ni Etc. can be used.

  The Curie point of the first device 3 is, for example, −77 ° C. or higher, preferably −10 ° C. or higher, for example, 1300 ° C. or lower, preferably 900 ° C. or lower.

  The relative dielectric constant of the first device 3 (insulator (dielectric)) is, for example, 1 or more, preferably 100 or more, more preferably 2000 or more.

  In such a power generation system 1, the higher the relative dielectric constant of the first device 3 (insulator (dielectric)), the higher the energy conversion efficiency and the higher voltage can be taken out. If the relative dielectric constant is less than the above lower limit, the energy conversion efficiency is low, and the voltage of the obtained power may be low.

  The first device 3 (insulator (dielectric)) is electrically polarized by the temperature change of the heat source 2, and the electrical polarization may be any of electronic polarization, ionic polarization, and orientation polarization.

  For example, it is expected that a material that exhibits polarization by orientation polarization (for example, a liquid crystal material) can improve power generation efficiency by changing its molecular structure.

  In FIG. 1, the second device 4 is provided to extract power from the first device 3.

  More specifically, the second device 4 is not particularly limited, but, for example, two electrodes (for example, a copper electrode, a silver electrode, etc.) disposed opposite to each other with the first device 3 interposed therebetween, for example, ., And the like, and are electrically connected to the first device 3.

  The temperature sensor 8 is provided close to or in contact with the first device 3 in order to detect the temperature of the first device 3. The temperature sensor 8 directly detects the surface temperature of the first device 3 as the temperature of the first device 3, or detects the ambient temperature around the first device 3, for example, an infrared radiation thermometer, A known temperature sensor such as a thermocouple thermometer is used.

  The voltage application device 9 is provided directly or close to the first device 3 in order to apply a voltage to the first device 3. Specifically, the voltage application device 9 includes, for example, two electrodes (for example, a copper electrode, a silver electrode, and the like) that are arranged to face each other with the first device 3 interposed therebetween, separately from the second device 4 described above. A voltage application power source V and a conductive wire connected thereto are provided, and the first device 3 and the second device 4 are disposed between the electrodes.

  The control unit 10 is a unit (for example, ECU: Electronic Control Unit) that performs electrical control in the power generation system 1, and is configured by a microcomputer including a CPU, a ROM, a RAM, and the like.

  The control unit 10 is electrically connected to the temperature sensor 8 and the voltage application device 9, and will be described in detail later. When the temperature sensor 8 detects the temperature rise or temperature drop of the first device 3, the control unit 10 is described later. Then, the voltage application device 9 is activated or stopped.

  In the power generation system 1 shown in FIG. 1, the second device 4 is electrically connected to a booster 5, an AC / DC converter (AC-DC converter) 6, and a battery 7 in order.

  In order to generate power with such a power generation system 1, for example, first, the temperature of the heat source 2 is changed over time, preferably periodically, and the first device 3 is heated and / or heated by the heat source 2. Or cool.

  The first device 3 described above is preferably electrically polarized periodically in accordance with such a temperature change. Thereafter, the electric power is taken out as a waveform (for example, alternating current, pulsating current, etc.) that periodically fluctuates according to the periodic electric polarization of the first device 3 through the second device 4.

  In such a power generation system 1, the temperature of the heat source 2 is, for example, 200 to 1200 ° C., preferably 700 to 900 ° C. in the high temperature state, and the temperature in the low temperature state is lower than the temperature in the high temperature state. More specifically, for example, 100 to 800 ° C., preferably 200 to 500 ° C., and the temperature difference between the high temperature state and the low temperature state is, for example, 10 to 600 ° C., preferably 20 to 500 ° C. is there.

  Moreover, the repetition period of these high temperature states and low temperature states is, for example, 10 to 400 cycles / second, preferably 30 to 100 cycles / second.

  In such a power generation system 1, a voltage is applied to the first device 3 in accordance with the temperature state of the first device 3 in order to generate power more efficiently.

  That is, in this power generation system 1, along with the heating and / or cooling by the heat source 2 described above, the temperature of the first device 3 is continuously measured by the temperature sensor 8, and the first device 3 is in a temperature rising state. Detect if the temperature is falling. More specifically, for example, when the temperature of the first device 3 detected by the temperature sensor 8 has increased by a predetermined value (for example, 0.2 ° C./s) or more, the temperature rise state In addition, when the temperature of the first device 3 drops by a predetermined value (for example, 0.2 ° C./s) or the like, it is detected that the temperature is lowered.

  In the power generation system 1, when it is detected that the first device 3 is in the temperature rising state, the control unit 10 operates the voltage application device 9 to apply a predetermined voltage to the first device 3.

  As the applied voltage, the strength of the electric field is, for example, 0.2 kV / mm or more, preferably 0.4 kV / mm or more, for example, 5 kV / mm or less, preferably 4 kV / mm or less.

  If the applied voltage (electric field) is in the above range, the amount of energy extracted from the first device 3 and the amount of energy consumed by the voltage application device 9 can be balanced, and power can be generated with excellent efficiency. it can.

  Further, the voltage application time is until the first device 3 reaches the temperature-decreasing state, and specifically, the temperature-rising state.

  When it is detected that the first device 3 is in the temperature-decreasing state, the voltage applying device 9 is stopped by the control unit 10 and the voltage application to the first device 3 is stopped.

  The time for stopping the application of the voltage is until the first device 3 reaches the temperature rising state, specifically, the temperature falling state.

  In addition, the time required from when the voltage applying device 9 is activated until the voltage is applied (that is, the intensity of the electric field reaches the predetermined value), and after the voltage applying device 9 is stopped, the electric field The time required until the strength reaches 0 kV / mm can be regarded as substantially 0 second.

  That is, in the power generation system 1, the time during which the voltage less than the predetermined value is applied is substantially 0 second, and the voltage is applied when the voltage of the predetermined value is applied (ON). The state of being not applied (OFF) is switched by the control unit 10.

  As described above, in the power generation system 1 described above, when the temperature rise of the first device 3 is detected, the voltage applying device 9 is activated and a voltage is applied to the first device 3. On the other hand, when the temperature drop of the first device 3 is detected, the voltage application device 9 is stopped and the application of the voltage is stopped.

  According to such a power generation system 1, the first device 3 is more efficient than a case where no voltage is applied by a relatively simple method of operating or stopping the voltage application device 9, that is, an ON / OFF operation. Thus, energy can be extracted and power generation efficiency can be improved.

  In such a power generation system 1, the first device 3 may be in a constant temperature state (the amount of change in temperature is a predetermined value (for example, 0. Less than 2 ° C./s)). In such a case, the voltage is applied during the temperature increase of the first device 3 and during the constant temperature state after the temperature increase, and the application of the voltage is stopped during the temperature decrease and during the constant temperature state after the temperature decrease. As will be described later, when the internal combustion engine 11 of the automobile is employed as the heat source 2, the first device 3 repeats the temperature rising state and the temperature lowering state without substantially becoming the constant temperature state.

  Further, as a method for improving the power generation efficiency, not only the voltage applying device 9 is simply operated and stopped as described above, but also, for example, the magnitude of the applied voltage is changed according to the temperature state of the first device 3. It is also considered to make it. However, such a method requires a cumbersome operation of gradually increasing or decreasing the applied voltage, which is troublesome.

  On the other hand, in the power generation system 1 described above, the power generation efficiency can be improved by a relatively simple method of operating or stopping the voltage application device 9.

  Furthermore, the first device 3 may be damaged when exposed to an environment exceeding its Curie point, and the power generation performance may be reduced or power generation may not be possible. However, in the power generation system 1 described above, since the voltage is applied when the temperature of the first device 3 is raised, the first device 2 can be used even when exposed to an environment exceeding its Curie point. The device 3 can be prevented from being damaged, and the power generation performance of the power generation system 1 can be prevented from being lowered or the power generation is disabled. As a result, it is possible to generate power with excellent efficiency even in a high temperature environment.

  In such a power generation system 1, the extracted power is boosted in a state of a periodically varying waveform (for example, alternating current, pulsating current, etc.) in the booster 5 connected to the second device 4. As the booster 5, a booster capable of boosting AC voltage with excellent efficiency by a simple configuration using, for example, a coil and a capacitor is used.

  Next, the electric power boosted by the booster 5 is converted into a DC voltage by the AC / DC converter 6 and then stored in the battery 7.

  According to such a power generation system 1, since the heat source 2 whose temperature rises and falls with time is used, a fluctuating voltage (for example, an AC voltage) can be extracted, and as a result, a constant voltage (DC voltage) is extracted. Compared to the above, it is possible to store the electric power by boosting with excellent efficiency by a simple configuration.

  In addition, if the heat source 2 is a heat source that periodically changes in temperature, electric power can be extracted as a waveform that varies periodically. As a result, the electric power can be boosted with higher efficiency and stored with a simple configuration. can do.

  FIG. 2 is a schematic configuration diagram showing an embodiment in which the power generation system of the present invention is mounted on a vehicle, and FIG. 3 is an enlarged view of a main part of the power generation system shown in FIG.

  In FIG. 2, the automobile 25 includes an internal combustion engine 11, a catalyst mounting portion 12, an exhaust pipe 13, a muffler 14, and a discharge pipe 15.

  The internal combustion engine 11 includes an engine 16 and an exhaust manifold 17.

  The engine 16 is a multi-cylinder (4-cylinder type) multi-cycle (4-cycle) engine, and an upstream end portion of a branch pipe 18 (described later) of the exhaust manifold 17 is connected to each cylinder.

  The exhaust manifold 17 is an exhaust manifold provided for converging exhaust gas exhausted from each cylinder of the engine 16, and a plurality of (four) branch pipes 18 (these are connected to each cylinder of the engine 16. 2 are referred to as the branch pipe 18a, the branch pipe 18b, the branch pipe 18c, and the branch pipe 18d in this order from the upper side in FIG. And an air collecting tube 19 that integrates 18 into one.

  Each branch pipe 18 includes one box-shaped space 20 in the middle of the flow direction. The box-shaped space 20 is a substantially rectangular parallelepiped space interposed so as to communicate with the branch pipe 18, and inside the plurality of first devices 3 and second devices 4 (not shown). (See FIG. 3).

  In FIG. 2, the plurality of first devices 3 are simplified, one first device 3 is shown for one box-shaped space 20, and the description of the second device 4 is omitted. Yes.

  In such an exhaust manifold 17, the upstream end of the branch pipe 18 is connected to each cylinder of the engine 16, and the downstream end of the branch pipe 18 and the upstream end of the air collecting pipe 19 are connected to each other. It is connected. Further, the downstream end of the air collecting pipe 19 is connected to the upstream end of the catalyst mounting portion 12.

The catalyst mounting unit 12 includes, for example, a catalyst carrier and a catalyst coated on the catalyst carrier, and includes hydrocarbons (HC), nitrogen oxides (NO _x ), exhaust gas exhausted from the internal combustion engine 11, In order to purify harmful components such as carbon monoxide (CO), it is connected to the downstream end of the internal combustion engine 11 (exhaust manifold 17).

  The exhaust pipe 13 is provided to guide the exhaust gas purified in the catalyst mounting portion 12 to the muffler 14. The upstream end is connected to the catalyst mounting portion 12 and the downstream end is the muffler 14. It is connected to the.

  The muffler 14 is provided to silence noise generated in the engine 16 (in particular, an explosion process), and an upstream end thereof is connected to a downstream end of the exhaust pipe 13. The downstream end of the muffler 14 is connected to the upstream end of the discharge pipe 15.

  The exhaust pipe 15 is provided to discharge exhaust gas that has been exhausted from the engine 16 and sequentially passes through the exhaust manifold 17, the catalyst mounting portion 12, the exhaust pipe 13, and the muffler 14, and has been purified and silenced. The upstream end is connected to the downstream end of the muffler 14, and the downstream end is open to the outside air.

  The automobile 25 is equipped with the power generation system 1 described above.

  As described above, the power generation system 1 includes the heat source 2, the first device 3, the second device 4, the temperature sensor 8, the voltage application device 9, and the control unit 10.

  In this power generation system 1, the engine 16 of the internal combustion engine 11 is used as the heat source 2, and as shown in an enlarged view and FIG. 3, the box-shaped space 20 of each branch pipe 18 includes One device 3 is arranged.

  The first device 3 is formed in a sheet shape, and a plurality of first devices 3 are arranged in the box-shaped space 20 with a space therebetween, and a second device 4 (and a fixing member (not shown) provided as necessary). Z)).

  As a result, both the front and back surfaces of the first device 3 and the peripheral side surface are exposed to the outside air in the box-shaped space 20 via the second device 4 (not shown) and can be exposed (exposed) to the exhaust gas. It is said that.

  Although not shown, the second device 4 includes two electrodes arranged opposite to each other with the first device 3 interposed therebetween, and a conductive wire connected to these electrodes.

  As shown in the enlarged view of FIG. 2, the temperature sensor 8 is disposed in the vicinity of the upstream side (exhaust gas flow direction) of the plurality of first devices 3 in each branch pipe 18, and can detect the temperature thereof. Is provided.

  Note that the number of the temperature sensors 8 is not particularly limited as long as the temperature sensors 8 can be provided so as to detect the temperatures of the plurality of first devices 3 (see FIG. 3), and one or a plurality of the temperature sensors 8 are provided as necessary.

  The voltage application device 9 includes a plurality (two for one first device 3) of electrodes 22, and each electrode 22 faces each other outside the first device 3, and the first device 3 It arrange | positions so that it may interpose. Each of these electrodes 22 is connected in parallel by a branch conductor or the like. By applying a voltage to the electrodes 22 from the voltage application power supply V, a voltage can be applied between the electrodes 22, that is, the first device 3.

  In FIG. 2, one first device 3 and a pair of electrodes 22 arranged to face each other with the first device 3 interposed therebetween are schematically shown in each box-shaped space 20.

  The control unit 10 is electrically connected to all the temperature sensors 8 and the voltage application devices 9 as indicated by broken lines outside the box-shaped space 20.

  Specifically, the control unit 10 is connected in parallel to each of the temperature sensors 8 provided in each box-type space 20 by a branched conducting wire or the like, and is connected to the voltage application device 9.

  Further, as shown in FIG. 2, the power generation system 1 is sequentially electrically connected to the booster 5, the AC / DC converter 6, and the battery 7.

  In such an automobile 25, when the engine 16 is driven, the pistons are repeatedly moved up and down in each cylinder, and the intake process, the compression process, the explosion process, and the exhaust process are sequentially performed. Is done.

  More specifically, for example, in two cylinders, that is, a cylinder connected to the branch pipe 18a and a cylinder connected to the branch pipe 18c, the pistons are interlocked to perform the intake process, the compression process, the explosion process, and the exhaust process. , Implemented in phase. As a result, the fuel is combusted and power is output, and high-temperature exhaust gas passes through the branch pipe 18a and the branch pipe 18c in the exhaust process.

  At this time, the heat of the engine 16 is transmitted through the exhaust gas (heat medium), the internal temperatures of the branch pipe 18a and the branch pipe 18c rise in the exhaust process, and other processes (intake process, compression process, explosion) In step (5), it moves up and down with time according to the piston cycle, and the high temperature state and the low temperature state are periodically repeated.

  On the other hand, in the two cylinders, the cylinder connected to the branch pipe 18b and the cylinder connected to the branch pipe 18d at different timings from the two cylinders, the pistons are interlocked, and the intake process, the compression process, The explosion process and the exhaust process are performed in the same phase. As a result, fuel is combusted and power is output, and at a timing different from that of the branch pipe 18a and the branch pipe 18c, high-temperature exhaust gas passes through the branch pipe 18b and the branch pipe 18d in the exhaust process.

  At this time, the heat of the engine 16 is transmitted through the exhaust gas (heat medium), the internal temperatures of the branch pipe 18b and the branch pipe 18d rise in the exhaust process, and other processes (intake process, compression process, explosion) In step (5), it moves up and down with time according to the piston cycle, and the high temperature state and the low temperature state are periodically repeated.

  This periodic temperature change has the same period but a different phase from the periodic temperature changes of the branch pipe 18a and the branch pipe 18c.

  In the power generation system 1, as described above, the sheet-like first device 3 is disposed inside each branch pipe 18 (in the box-shaped space 20).

  Therefore, when the exhaust gas exhausted from the engine 16 (heat source 2) is introduced into the branch pipe 18 and filled into the box-shaped space 20, the surface of the first device 3 and the surface of the first device 3 and Both surfaces of the back surface (and also the peripheral surface) are brought into contact (exposed) with exhaust gas (heat medium) (via the second device 4), and heated and / or cooled.

  That is, both the front surface and the back surface of the first device 3 are heated and / or cooled by the temperature change over time of the engine 16 (heat source 2) and the heat medium that transfers the heat of the engine 16.

  And thereby, the 1st device 3 can be periodically made into a high temperature state or a low temperature state, and the effect (for example, piezo element, pyroelectric element, etc.) according to the element (for example, piezo element, pyroelectric element, etc.) , Piezo effect, pyroelectric effect, etc.).

  Therefore, in this power generation system 1, power can be extracted from each first device 3 through the second device 4 as a waveform (for example, alternating current, pulsating current) that periodically varies.

  Further, in the power generation system 1, as described above, the temperature of the first device 3 is continuously detected by the temperature sensor 8.

  When the temperature rise of the first device 3 is detected, the voltage application device 9 is activated to apply a voltage to the first device 3. On the other hand, when the temperature drop of the first device 3 is detected, the voltage application device 9 is stopped, and the voltage application is stopped.

  Thereby, in said electric power generation system 1, it can aim at the improvement of electric power generation efficiency, and also suppresses that the 1st device 3 is damaged even when the temperature of the 1st device 3 exceeds a Curie point. it can.

  Further, in this power generation system 1, since the temperature of the branch pipe 18a and the branch pipe 18c and the temperature of the branch pipe 18b and the branch pipe 18d change periodically with the same period and different phases, Can be continuously extracted as a waveform (for example, alternating current, pulsating flow, etc.) that fluctuates automatically.

  Then, after passing through each branch pipe 18, the exhaust gas is supplied to the air collection pipe 19, collected, then supplied to the catalyst mounting section 12, and purified by the catalyst provided in the catalyst mounting section 12. Thereafter, the exhaust gas is supplied to the exhaust pipe 13, silenced in the muffler 14, and then discharged to the outside air through the discharge pipe 15.

  At this time, since the exhaust gas passing through each branch pipe 18 is collected in the air collection pipes 19, the exhaust gas sequentially passes through the air collection pipe 19, the catalyst mounting portion 12, the exhaust pipe 13, the muffler 14, and the exhaust pipe 15. The temperature is smoothed.

  Therefore, the temperature of the air collection pipe 19, the catalyst mounting portion 12, the exhaust pipe 13, the muffler 14 and the exhaust pipe 15 through which such exhaust gas whose temperature has been smoothed normally does not increase or decrease with time, It is constant.

  Therefore, when the air collecting tube 19, the catalyst mounting portion 12, the exhaust pipe 13, the muffler 14 or the exhaust pipe 15 is used as the heat source 2 and the first device 3 is disposed around or inside the first device 3, The electric power taken out from is low in voltage and constant (DC voltage).

  Therefore, in such a method, there is a problem that the obtained electric power cannot be boosted efficiently with a simple configuration and the power storage efficiency is poor.

  On the other hand, as described above, if the first device 3 is arranged in the internal space of the branch pipe 18, the first device 3 is periodically brought into a high temperature state or a low temperature state due to a temperature change of the heat source 2 over time. The first device 3 can be periodically electrically polarized by an effect (for example, piezo effect, pyroelectric effect, etc.) according to the device (for example, piezo element, pyroelectric element, etc.).

  Therefore, in this power generation system 1, power can be extracted from each first device 3 through the second device 4 as a waveform (for example, alternating current, pulsating current) that periodically varies.

  Thereafter, in this method, for example, as indicated by a dotted line in FIG. 2, the electric power obtained as described above is periodically changed in the booster 5 connected to the second device 4 (for example, AC, pulse, etc.). And then the boosted power is converted into a DC voltage by the AC / DC converter 6 and then stored in the battery 7. The electric power stored in the battery 7 can be appropriately used as the power of the automobile 25 or various electric components mounted on the automobile 25.

  And according to such a power generation system 1, since the heat source 2 whose temperature rises and falls with time is used, a fluctuating voltage (for example, AC voltage) can be taken out, and as a result, as a constant voltage (DC voltage) Compared with the case of taking out and converting by a DC-DC converter, it is possible to store the electric power by boosting with excellent efficiency.

  EXAMPLES Next, although this invention is demonstrated based on an Example, this invention is not limited by the following Example.

Example 1
Bulk type piezo element (first device with silver electrode (second device) formed on the front and back surfaces, structure: PZT, Curie point (Tc) 295 ° C., relative dielectric constant: 2130, product number: C-6 Manufactured by Fuji Ceramics Co., Ltd.) was cut into a sheet having a size of 15 mm long × 10 mm wide × 0.5 mm thick.

  Next, a 100 kΩ resistive element was placed in parallel with the piezo element. The resistance element was provided in order to confirm current characteristics clearly.

  As a heat source, an engine (3 cylinders: 4 cycles) connected to a dynamometer (model number: KF engine, manufactured by Daihatsu Kogyo Co., Ltd.) is used. One pipe through which exhaust gas passes is selected, and the pipe length from the engine is 55 cm. A box-shaped space was formed at a position where the above sample was placed.

  Next, a thermocouple (temperature sensor) was arranged so that the temperature of each sample could be detected, and the sample was sandwiched between electrodes of a voltage application device (model number: MODEL677B, manufactured by Trek Japan) so that a voltage could be applied. Then, the voltage application power source and the control unit were arranged outside the box-shaped space and were electrically connected to each other.

  In the control unit (CPU), the temperature of the sample measured by the thermocouple is in a temperature rising state when the temperature rises by 0.2 ° C./s or more, and the temperature is lowered when the temperature decreases by 0.2 ° C./s or more. Set to be in state.

  Thereafter, the engine was operated in JC08 mode, and the sample was exposed to exhaust gas whose temperature increased and decreased over time. As a result, the temperature of the piezo element was increased and decreased over time and the electric polarization was performed, and the generated voltage (electric power) was taken out via the electrode and the conductive wire.

  In addition, the temperature (average value) of the sample was measured with a thermocouple, and when it was detected that the sample was in a heated state, a voltage (electric field strength: 0.25 kV / mm) was applied to the sample.

  And the voltage change of the electric power taken out from the sample was observed with the voltmeter.

  In this way, the engine operation in the JC08 mode was repeated. The relationship between applied voltage and temperature change is shown in FIG. Further, FIG. 5 shows the generated voltage until 350 seconds elapse after starting operation in the JC08 mode, together with the relationship between the applied voltage and the temperature change during that time.

DESCRIPTION OF SYMBOLS 1 Power generation system 2 Heat source 3 1st device 4 2nd device 5 Booster 6 AC / DC converter 7 Battery 8 Temperature sensor 9 Voltage application apparatus 10 Control unit

Claims (1)

A heat source whose temperature rises and falls over time;
A first device in which the temperature is increased and decreased over time due to a temperature change of the heat source and is electrically polarized;
A second device for extracting power from the first device;
Detecting means for detecting the temperature of the first device;
Voltage applying means for applying a voltage to the first device;
When the temperature of the first device is detected by the detection means, the voltage application means is activated,
And a control means for stopping the voltage application means when a temperature drop of the first device is detected.

Images