JP2006206931A - Hydrogen-generating device, and power-generating system for generating electricity by using hydrogen generated in the hydrogen-generating device as fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for generating hydrogen in a system using an internal combustion engine, and to further provide a system for generating electricity with the use of the generated hydrogen to prevent a secondary battery from decreasing the discharging capacity. <P>SOLUTION: A hydrogen-generating device 7 comprises a proton-conductive solid electrolyte 75 having a pair of electrodes 76 and 77, and a voltage application means 2 and 17 for applying direct voltage to a pair of the electrodes. The power-generating system comprises the steps of: contacting one electrode 76 out of a pair of the electrodes in the hydrogen-generating device 7 with a gas exhausted from an internal combustion engine 1, in a state of having applied direct voltage to a pair of the electrodes to electrolyze moisture contained in the exhaust gas; thereby generating hydrogen from the other electrode 77 of a pair of the electrodes, which does not contact with the exhaust gas; storing hydrogen generated from the hydrogen-generating device 7 in a hydrogen storage means 9; and when the internal combustion engine 1 stops working, supplying the hydrogen stored in the hydrogen storage means 9 to a fuel cell 12 to make the fuel cell 12 generate electric energy and supply the electric energy to the secondary battery 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydrogen generator that generates hydrogen from exhaust gas of an internal combustion engine, and a power generation system that generates power using hydrogen generated by the hydrogen generator.

  In recent years, with the increase in the number of auxiliary equipment mounted on the vehicle and the increase in its functions, the consumption current (dark current) of the auxiliary equipment increases while the vehicle is stopped, and the battery mounted on the vehicle can be discharged excessively. There is sex. In general, a battery mounted on a vehicle undergoes self-discharge during a rest period, and the charge capacity naturally decreases. For this reason, when the stop period of the vehicle is long, the battery capacity decreases significantly. This tendency results in further facilitating capacity reduction when the balance between charging and discharging of the battery is lost due to an increase in the electric load while the vehicle is running.

  Generally, in a vehicle having an internal combustion engine as a main driving source for driving, the internal combustion engine is started by receiving power supply from the battery, and the battery is excessively discharged while the internal combustion engine is stopped. In such a case, the internal combustion engine cannot be restarted. There is a solution to such a problem such as increasing the capacity of the battery. However, increasing the capacity of the battery without limit is limited in terms of weight and space in the vehicle. For this reason, a method of charging the battery or limiting the discharge by some method has been devised.

For example, a configuration (Patent Document 1) that detects a battery before it is excessively discharged and stops energization of a device that generates dark current (or Patent Document 1), or a vehicle equipped with a plurality of batteries, from one battery to the other The structure (patent document 2) which charges a battery is proposed. In addition, in the case of a long-term stop such as transportation, a configuration in which a switch for shutting off the auxiliary machine and the battery is separately devised (Patent Document 3). Furthermore, the structure which provides a solar cell and ventilates the air in a vehicle during parking with the generated electric power, or supplies surplus electric power to a battery is also proposed (patent document 4).
JP 2004-168263 A JP 2002-209301 A Japanese Patent Laid-Open No. 10-070843 JP 2003-297044 A

  However, the configuration of Patent Document 1 has a problem that occurs due to the stop of energization of the device, and the configuration of Patent Document 2 has limitations such as being limited to an electric vehicle or an electric / internal combustion engine hybrid vehicle. In addition, in the configuration of Patent Document 3, there is a problem that information in the memory is lost during energization stop, in addition to the trouble of manually operating the switch. Furthermore, the configuration of Patent Document 4 has a problem that power generation cannot be expected when the vehicle is placed indoors where it is not exposed to sunlight.

  In addition, it is conceivable to use a fuel cell that has been put into practical use in recent years to generate power while the internal combustion engine is stopped, and to charge the battery. However, there is a problem that hydrogen as fuel for the fuel cell must be secured.

  The present invention has been made in view of the above points, and an object of the present invention is to generate hydrogen in a system using an internal combustion engine. It is another object of the present invention to prevent the charge capacity of a secondary battery that generates electric power using the generated hydrogen and supplies electric power necessary for starting an internal combustion engine from decreasing.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a hydrogen generator for generating hydrogen from moisture contained in the exhaust gas of the internal combustion engine (1), comprising a pair of electrodes (76, 77). A proton conductive solid electrolyte body (75) and voltage applying means (2, 17) for applying a DC voltage to the pair of electrodes, and one of the pair of electrodes in a state where the DC voltage is applied to the pair of electrodes. The electrode (76) is brought into contact with the exhaust gas of the internal combustion engine (1), the water contained in the exhaust gas is electrolyzed, and hydrogen is generated from the other electrode (77) of the pair of electrodes not in contact with the exhaust gas. It is characterized by letting.

  Thus, hydrogen can be obtained by electrolyzing moisture contained in the exhaust gas of the internal combustion engine (1), and water contained in the high-temperature exhaust gas discharged from the internal combustion engine (1) is used. As a result, it is possible to simultaneously secure raw materials for hydrogen generation and to effectively use thermal energy.

  Further, as in the invention described in claim 2, the electrolysis reaction of water can be promoted by providing a catalyst on at least the side of the pair of electrodes (76, 77) in contact with the exhaust gas.

  According to a third aspect of the present invention, the hydrogen generator (7) according to the first or second aspect, a fuel cell (12) for generating electric energy by an electrochemical reaction between hydrogen and oxygen, and hydrogen generation A hydrogen storage means (9) for storing hydrogen generated by the device (7) and supplying the stored hydrogen to the fuel cell, and a secondary battery (2) for supplying electric power necessary for starting the internal combustion engine (1) And an electric load (3) that consumes electric power when the internal combustion engine (1) is stopped and is supplied with power from the secondary battery (2) when the internal combustion engine (1) is stopped. At the time of stoppage, hydrogen is supplied to the fuel cell (12) by the hydrogen storage means (9) to generate electric energy in the fuel cell (12), and this electric energy is supplied to the secondary battery (2) or the electric load (3). Characterized by supplying to either one To have.

  In this way, by using the hydrogen obtained from the exhaust gas of the internal combustion engine (1) and generating the fuel cell (12) while the internal combustion engine (1) is stopped, the charge capacity of the secondary battery is reduced. Can be prevented. Thereby, when the internal combustion engine (1) is started next time, electric power necessary for starting the internal combustion engine (1) can be supplied from the secondary battery (2).

  Further, the invention described in claim 4 is characterized by comprising voltage conversion means (16) for boosting the power generation voltage of the fuel cell (12). This eliminates the need to increase the number of fuel cells in order to make the power generation voltage of the fuel cell (12) a voltage that can be supplied to the secondary battery (2) or the electric load (3). It can be simplified.

  Further, the hydrogen storage means (9) can store hydrogen in the hydrogen storage alloy using the hydrogen storage alloy as in the invention described in claim 5, and further, as in the invention described in claim 6. A high-pressure tank capable of storing high-pressure hydrogen can also be used.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the first embodiment, the hydrogen generator of the present invention and a power generation system that generates electricity using hydrogen generated by the hydrogen generator as a fuel is charged for a secondary battery used in a vehicle using an internal combustion engine as a driving source for travel. This is applied to a secondary battery charging system.

  FIG. 1 shows an overall configuration of a secondary battery charging system including a hydrogen generator 7 according to the first embodiment. The secondary battery charging system includes an internal combustion engine 1, a secondary battery 2, and an electric load 3.

  As the internal combustion engine 1, a gasoline engine or a diesel engine can be used. The internal combustion engine 1 generates exhaust gas by burning fuel. Exhaust gas generated in the internal combustion engine 1 is discharged outside through an exhaust pipe 5 via a manifold 4. This exhaust gas contains water vapor. For example, when a gasoline engine is used as the internal combustion engine 1, the exhaust gas contains high-temperature steam of about 12% or more in molar ratio by combustion with theoretical air fuel consumption.

  The secondary battery 2 stores electric power generated by an alternator (not shown) during operation of the internal combustion engine 1 and supplies electric power to various auxiliary machines. The secondary battery 2 is configured to supply power to a starter (not shown) used when starting the internal combustion engine 1. The electric load 3 is required to be energized constantly even when the internal combustion engine 1 is stopped, and is, for example, a clock or a remote-controlled door lock switch. The electric load 3 is supplied with electric power generated by an alternator when the internal combustion engine 1 is operating, and is supplied with power from the secondary battery 2 when the internal combustion engine 1 is stopped.

  As shown in FIG. 1, an exhaust pipe 5 for exhausting exhaust gas from an internal combustion engine 1 includes a catalytic converter 6 for purifying exhaust gas, and hydrogen that generates hydrogen from moisture (water vapor) contained in the exhaust gas. A generator 7 is provided. The hydrogen generator 7 will be described in detail later.

  A hydrogen storage container 9 is connected to the hydrogen generator 7 via a first hydrogen supply path 8, and hydrogen generated in the hydrogen generator 7 is supplied to the hydrogen storage container 9 via a first hydrogen supply path 8. The A check valve 10 is provided in the first hydrogen supply path 8, and the hydrogen passing through the first hydrogen supply path 8 by the check valve 10 flows only in the direction from the hydrogen generator 7 toward the hydrogen storage container 9. . The hydrogen storage container 9 corresponds to the hydrogen storage means of the present invention.

The hydrogen storage container 9 contains a hydrogen storage alloy 9a capable of storing and releasing hydrogen. As the hydrogen storage alloy 9a, for example, a LaNi ₅ type alloy can be used. The hydrogen storage container 9 is connected to the fuel cell 12 via the second hydrogen supply path 11. The second hydrogen supply path 11 is provided with a valve 13 that can open and close the second hydrogen supply path 11. When the valve 13 is closed, the hydrogen supply to the fuel cell 12 is interrupted, and when the valve 13 is opened, the hydrogen supply to the fuel cell 12 is performed.

  The fuel cell 12 generates power for charging the secondary battery 2 when the internal combustion engine is stopped. The generated power of the fuel cell 12 may be about 50 mA × 12 V = 0.6 W, assuming that the electromotive force of the secondary battery 2 is 12 V and the current consumption of the electric load 3 is about 50 mA. In the present embodiment, more power (for example, 10 W) is generated by the fuel cell 12 to charge the secondary battery 2 and the state of the secondary battery 2 is rapidly recovered.

  As the fuel cell 12, a polymer electrolyte fuel cell can be suitably used. Since the solid polymer electrolyte membrane fuel cell operates at room temperature, it is easy to use even when the vehicle is stopped. The fuel cell 12 uses pure hydrogen as a fuel and air as an oxidant. Such a fuel cell 12 includes a fuel cell comprising a proton conductive polymer electrolyte membrane such as Nafion (manufactured by DuPont) and a pair of electrodes coated with a catalyst. The fuel cell is an electrolyte membrane. It is composed of MEA (Membrane Electrode Assembly) in which electrodes are arranged on both sides. The fuel cell 12 of this embodiment includes a single layer fuel cell.

  Hydrogen is supplied from the hydrogen storage container 9 to the anode (hydrogen electrode) of the fuel cell 12. Since the fuel cell 12 of this embodiment has a small generated power of about 10 W, it is not always necessary to forcibly supply air, and air is supplied to the cathode (oxidation electrode) of the fuel cell 12 using natural convection. The

  The secondary battery charging system of this embodiment includes a control unit 14. The control unit 14 includes a control circuit 15, a voltage conversion circuit 16, and a DC / DC converter 17. The control circuit 15 is configured by a known microcomputer including a CPU, a ROM, a RAM, an I / O, and the like, and executes processing such as various calculations according to a program stored in the ROM. The control circuit 15 of the present embodiment detects the state of charge of the secondary battery 2 and performs opening / closing control of the valve 13 based on this. The voltage conversion circuit 16 corresponds to the voltage conversion means of the present invention.

  The voltage conversion circuit 16 boosts the electric energy generated in the fuel cell 12 to a voltage at which the secondary battery 2 can be charged. Since the power generation voltage of the fuel cell 12 composed of a single cell of this embodiment is about 0.5 to 0.8 V, the voltage is boosted to the electromotive force (for example, 12 V) of the secondary battery 2 by the voltage conversion circuit 16. .

  FIG. 2 is a circuit diagram showing a configuration of the voltage conversion circuit 16. As shown in FIG. 2, the voltage conversion circuit 16 is a well-known booster circuit, and includes a switch 16a that opens and closes by a start signal from the control circuit 15, a boost control circuit 16b, and a DC / DC converter unit 16c. The DC / DC converter unit 16c includes a coil 16d, switch elements 16e and 16f, and capacitors 16g and 16h. The electrical energy stored in the coil 16d is switched by the switch elements 16e and 16f and smoothed by the capacitors 16g and 16h. To boost the pressure.

  Returning to FIG. 1, the DC / DC converter 17 generates a negative power source by reducing the voltage while reversing the current from the secondary battery 2, and the negative power source generates hydrogen via the electric wire 18. Supplied to the device 7.

  Next, the hydrogen generator 7 will be described with reference to FIG. FIG. 3 is a cross-sectional view of the hydrogen generator 7.

  As shown in FIG. 3, the hydrogen generator 7 is provided in the exhaust pipe 5. The hydrogen generator 7 of this embodiment is configured in a cylindrical shape similar to the cylindrical shape of the exhaust pipe 5. A flange-like flange 71 is formed at both ends of the hydrogen generator 7, and a flange 51 having the same shape is also formed at the connection portion of the hydrogen generator 7 in the exhaust pipe 5. These flanges 51 and 71 are fixed by a fastening member 52 through a gasket 53.

  The hydrogen generator 7 includes an outer casing 72 and an inner casing 73. In the present embodiment, both the outer casing 72 and the inner casing 73 are cylindrical, and both ends thereof are connected to the flange 71. The inner casing 73 has a diameter similar to that of the exhaust pipe 5, and the outer casing 72 has a larger diameter than the inner casing 73.

  The inner casing 73 is disposed inside the outer casing 72 so that the axial directions thereof coincide with each other. A predetermined space is provided between the outer casing 72 and the inner casing 73, and a hydrogen generation space 74 is formed. A first hydrogen supply path 8 is connected to the outer casing 72, and the hydrogen generation space 74 communicates with the first hydrogen supply path 8. The inner casing 73 has a role of maintaining the strength of the solid electrolyte body 75 in which the electrode portions 76 and 77 are formed on both sides, and protecting the solid electrolyte body 75 from water droplets contained in the low-temperature exhaust gas.

  On the outer wall surface of the inner casing 73, a proton conductive solid electrolyte body 75, a first electrode portion 76 as an anode, and a second electrode portion 77 as a cathode are provided. The electrode portions 76 and 77 are formed on the surface of the solid electrolyte body 75, and these electrode portions 76 and 77 are formed so as not to be in direct contact with each other. Further, the second electrode 77 is formed so that both ends thereof do not contact the flange 71. These are provided in order of the first electrode portion 76, the solid electrolyte body 75, and the second electrode body 77 from the outer wall surface of the inner casing 73.

  The inner casing 73 and the first electrode portion 76 are in electrical contact. The second electrode portion 77 is connected to the electric wire 18 and is connected to an external negative power source. The inner casing 73 has a mesh shape in which a large number of through holes are formed, and the exhaust gas passing through the exhaust pipe 5 can contact the first electrode portion 76.

Examples of the solid electrolyte body 75 include barium oxide, ceria (BaCeO ₃ ), strontium oxide / ceria (SrCeO ₃ ), strontium oxide / zirconia (SrZrO ₃ ), calcium oxide / zirconia (CaZrO ₃ ), strontium oxide / titania (SrTiO _3). A sintered body of oxide powder such as Moreover, it is preferable to use what added oxides, such as yttrium (Y), neodymium (Nd), ytterbium (Yb), and scandium (Sc), to these oxides. Furthermore, as the solid electrolyte body 75, a material obtained by substituting an alkali metal of a bichloro-type oxide with ammonium ions, such as NH ₄ NbWO ₆ or NH ₄ TaWO ₆ , can also be used.

  The thickness of the solid electrolyte body 75 is desirably about 0.5 cm. When the thickness exceeds 0.5 cm, the resistance when hydrogen ions permeate may increase. Conversely, when the thickness of the solid electrolyte body 75 is reduced, there are disadvantages such as being easily broken.

  The first electrode portion 76 is preferably a metal having a small oxygen overvoltage such as platinum, rhodium, iridium, etc., and one or a mixture of two or more of these metals may be used. As the second electrode portion 77, platinum, palladium, rhodium, ruthenium, iridium or the like is desirable, and one or a mixture of two or more of these metals may be used. Furthermore, as the second electrode 77, a catalyst such as copper oxide (CuO), cobalt oxide (CoO), or copper ion exchanged zeolite can be used. In particular, a mixture of these and a metal having a small hydrogen overvoltage such as platinum or palladium is preferable.

  The electrode portions 76 and 77 are formed by applying or printing a paste of an electrode forming compound on the surface of the solid electrolyte body 75 and firing the paste. Alternatively, the electrode portions 76 and 77 can be formed on the surface of the solid electrolyte body 75 by a method such as sputtering, vapor deposition, or plating. The thickness of the electrode portions 76 and 77 is preferably within a range of 1 to 1000 μm, but the thickness may be increased while maintaining gas permeability as a foamed material to improve the strength.

  Next, the operation of the secondary battery charging system of this embodiment will be described.

  First, the operation of the internal combustion engine 1 will be described. During operation of the internal combustion engine 1, exhaust gas generated in the internal combustion engine 1 is released to the outside through the exhaust pipe 5. The exhaust gas of the internal combustion engine 1 contains moisture, carbon dioxide, nitrogen and the like. The exhaust gas is discharged as a high-temperature gas of 300 to 800 ° C. At this time, a DC voltage is applied between the electrode portions 76 and 77 of the hydrogen generator 7 for water electrolysis. The voltage at this time may be a voltage that is about 0.3 V higher than the theoretical electrolysis voltage.

  In general, when water is electrolyzed to extract hydrogen, electrolysis can be performed with less energy when the temperature of water, that is, water vapor is higher. For example, the theoretical electrolysis partial pressure at room temperature is about 1.2 V, whereas it is about 1 V at 300 ° C. For this reason, the applied voltage can be lowered as the exhaust gas temperature is higher. By disposing the hydrogen generator 7 at a position close to the internal combustion engine 1 in the exhaust pipe 5, higher-temperature exhaust gas can be used.

  Thus, it is more efficient to perform electrolysis on high-temperature steam, and recovering hydrogen from the high-temperature exhaust gas of the internal combustion engine 1 results in energy recovery. Thereby, water as a raw material of hydrogen can be secured, and a part of waste heat of the internal combustion engine 1 that has been discarded as heat energy can be recovered.

The exhaust gas that has passed through the exhaust pipe 5 passes through the tubular hydrogen generator 1. The exhaust gas passing through the exhaust pipe 5 passes through the hole of the inner casing 73 and contacts the first electrode portion 76, and the water is electrolyzed into hydrogen and oxygen (2H ₂ O → 2H ⁺ + O ₂ + 2e ⁻ ). Hydrogen passes through the solid electrolyte body 75 in the form of hydrogen ions, and is reduced to hydrogen at the second electrode portion 77 (2H ⁺ + 2e ⁻ → H ₂ ). The electrolysis of water in the hydrogen generator 7 is performed almost theoretically. If there is no gas that permeates the solid electrolyte body 75, about 7 cc of hydrogen (converted to the standard state) can be obtained per 1A · minute.

  The hydrogen generated in the second electrode part 77 fills the hydrogen generation space 74 and is sent to the hydrogen storage container 9 via the first hydrogen supply path 8. The hydrogen generation space 74 rises to about 900 kPa at maximum with hydrogen generated by electrolysis. Thereby, since the hydrogen storage alloy 9a has a pressure higher than the equilibrium hydrogen pressure at the time of storing hydrogen, hydrogen can be stored in the hydrogen storage alloy 9a of the hydrogen storage container 9. At this time, since the valve 13 is closed, hydrogen is not supplied from the hydrogen storage container 9 to the fuel cell 12.

  Oxygen generated by electrolysis at the first electrode portion 76 passes through the exhaust pipe 5 together with other exhaust gases and is discharged to the outside.

  Next, a case where the vehicle is stopped for a long time will be described. This is an extreme case where the vehicle is manufactured and then transported overseas by ship, or if the vehicle is not used for a long time for some reason. Thus, when the vehicle is stopped for a long period of time, the secondary battery 2 is discharged by the dark current while the internal combustion engine 1 is stopped or by the electric load 3 that works even when the internal combustion engine 1 is stopped. If this is left unattended, the charge capacity of the secondary battery 2 will decrease, and the starter (not shown) will not operate when the internal combustion engine 1 is started next, causing the internal combustion engine 1 to be unable to start.

  For this reason, the control circuit 15 detects the SOC (charging state) of the secondary battery 2 when the internal combustion engine 1 is stopped, and when the SOC falls below a predetermined value, the charging control of the secondary battery 2 is performed. I do. The SOC of the secondary battery 2 can be estimated by measuring the open circuit voltage of the secondary battery 2, for example. The predetermined value for determining the start of the operation of the fuel cell 12 can be set to about 40% of the fully charged state of the secondary battery 2, for example.

  In the charging control of the secondary battery 2, the fuel cell 12 is activated. The fuel cell 12 is activated by opening the valve 13 and starting supplying hydrogen from the hydrogen storage container 9 to the fuel cell 12. At the same time, the voltage conversion circuit 16 is actuated to boost the voltage generated by the fuel cell 12 to a voltage that can charge the secondary battery 2 and charge the secondary battery 2.

  The control circuit 15 monitors the state of charge of the secondary battery 2 and stops the power generation by the fuel cell 12 when the state of charge of the secondary battery 2 is restored to a predetermined value. The fuel cell 12 is stopped by closing the valve 13.

  Since the charging control of the secondary battery 2 described above is performed while the internal combustion engine 1 is stopped, the power generation of the fuel cell 12 is stopped when the internal combustion engine 1 is started during the power generation of the fuel cell 12.

  As described above, hydrogen as fuel for the fuel cell 12 can be obtained by electrolyzing moisture contained in the exhaust gas of the internal combustion engine 1. As described above, by using the water vapor contained in the high-temperature exhaust gas flowing through the exhaust pipe 5, it is possible to simultaneously secure the raw material for hydrogen generation and effectively use the thermal energy. The secondary battery can be charged when the internal combustion engine 1 is stopped by using the hydrogen thus obtained to generate power in the fuel cell 12 while the internal combustion engine 1 is stopped.

  In addition, hydrogen can be obtained by electrolyzing water by an electrolysis method using a solid polymer electrolyte membrane, but in this method, when hydrogen ions move in the polymer electrolyte membrane, moisture is transferred, Water collects with hydrogen. For this reason, it is necessary to separate water from hydrogen to perform hydrogen storage, and a gas-liquid separator is required.

  On the other hand, according to the configuration using the solid electrolyte body 75 of the above embodiment, since only hydrogen is generated purely, there is an excellent effect that it is not necessary to provide a gas-liquid separator. In addition, by electrolyzing using water vapor contained in the exhaust gas of the internal combustion engine 1, it is not necessary to separately secure water as a raw material for hydrogen, so that water for electrolysis may freeze at low temperatures. Not a big advantage for vehicles.

  In the case of the solid polymer electrolysis method, if the generated hydrogen is higher than the normal pressure, it is difficult to increase the strength of the polymer film. However, in the configuration of the present embodiment, it is easy to set the gauge pressure to 900 kPa, for example. For this reason, hydrogen can be stored in the hydrogen storage alloy.

  Further, by providing the voltage conversion circuit 16, the power generation voltage of the fuel cell 12 can be boosted to a voltage necessary for charging the secondary battery 2 without increasing the number of cells of the fuel cell 12. Thereby, the structure of the fuel cell 12 can be simplified.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of the hydrogen generator 7 in the second embodiment.

As shown in FIG. 4, in the second embodiment, the inner casing 73, the solid electrolyte body 75, and the electrodes 76 and 77 are arranged so as to be orthogonal to the flow of exhaust gas in the exhaust pipe 5.
The inner casing 73 is formed in a cylindrical shape with one end closed, and the solid electrolyte body 75 and the electrodes 76 and 77 are formed in a cylindrical shape in which one end is hemispherical. The inner casing 73, the solid electrolyte body 75, and the electrodes 76 and 77 are arranged so as to protrude inside the exhaust pipe 5.

  According to the configuration of the second embodiment, the contact area between the exhaust gas and the first electrode unit 75 can be increased, the efficiency of water electrolysis can be improved, and the hydrogen generation efficiency can be improved. be able to.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view of the hydrogen generator 7 in the third embodiment.

  As shown in FIG. 5, in the third embodiment, the inner casing 73, the solid electrolyte body 75, and the electrodes 76 and 77 are arranged so as to be orthogonal to the flow of exhaust gas in the exhaust pipe 5. Two sets of the inner casing 73, the solid electrolyte body 75, and the electrodes 76 and 77 are provided. In the present embodiment, the inner casing 73, the solid electrolyte body 75, and the electrodes 76 and 77 are each formed in a cylindrical shape whose both ends are open, and are disposed so as to penetrate the inside of the exhaust pipe 5.

  According to the configuration of the third embodiment, the contact area between the exhaust gas and the first electrode unit 75 can be further increased, the efficiency of water electrolysis can be improved, and the hydrogen generation efficiency can be improved. Can be made.

(Other embodiments)
In the above embodiment, the electric energy generated in the fuel cell 12 is used for charging the secondary battery 2. However, the present invention is not limited to this, and the electric energy generated in the fuel cell 12 is directly supplied to the electric load 3. You may comprise as follows. In this case, a voltage conversion circuit 16 that boosts the power generation voltage of the fuel cell 12 may be provided between the fuel cell 12 and the electric load 3.

  Moreover, in the said embodiment, although the container filled with the hydrogen storage alloy was used as the hydrogen storage container 9, it is not restricted to this, You may use the high-pressure hydrogen tank filled with hydrogen by making it high pressure.

  In addition, a pressurizing unit such as a pump may be provided in the first hydrogen supply path 8, and the hydrogen generated by the hydrogen generator 7 may be pressurized by the pressurizing unit and filled in the hydrogen storage container.

  Further, when the hydrogen storage container 7 is provided with a pressure sensor for detecting the pressure in the container 7, hydrogen storage in the hydrogen storage container 7 proceeds by electrolysis of water, and when the detection value of the pressure sensor exceeds a predetermined value, It can be detected that the hydrogen storage container 7 is fully stored. Therefore, when the detected value of the pressure sensor exceeds a predetermined value, the energization to the hydrogen generator 7 can be stopped and the hydrogen generation can be stopped.

  Further, immediately after the internal combustion engine 1 is started, the temperature of the exhaust gas is low, and the hydrogen generation efficiency of the hydrogen generator 7 is poor. Therefore, the energization of the hydrogen generator 7 is not performed immediately after the internal combustion engine 1 is started. In this way, useless energization can be prevented.

  Moreover, in the said embodiment, although comprised from the single fuel cell of the fuel cell 12, it is not restricted to this, You may comprise the fuel cell 12 from several fuel cell. In this case, the voltage conversion circuit 16 becomes unnecessary or the configuration of the voltage conversion circuit 16 can be simplified.

  Further, when a hydrogen engine using hydrogen as fuel is used as the internal combustion engine 1, hydrogen generated by the hydrogen generator 7 can be reused as fuel for the hydrogen engine. Thereby, hydrogen generated from the exhaust gas of the internal combustion engine 1 can be used for applications other than the fuel of the fuel cell 12.

It is a conceptual diagram which shows the whole structure of the secondary battery charging system of 1st Embodiment. It is a circuit diagram of a voltage conversion circuit. It is sectional drawing of a hydrogen generator. It is sectional drawing of the hydrogen generator of 2nd Embodiment. It is sectional drawing of the hydrogen generator of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Secondary battery, 3 ... Electric load, 7 ... Hydrogen generator, 9 ... Hydrogen storage container, 12 ... Fuel cell, 15 ... Control circuit, 16 ... Voltage conversion circuit, 17 ... DC / DC converter .

Claims (6)

A hydrogen generator for generating hydrogen from moisture contained in exhaust gas of an internal combustion engine (1),
A proton conductive solid electrolyte body (75) having a pair of electrodes (76, 77);
Voltage application means (2, 17) for applying a DC voltage to the pair of electrodes,
The exhaust gas of the internal combustion engine (1) is brought into contact with one electrode (76) of the pair of electrodes in a state where a DC voltage is applied to the pair of electrodes, and water contained in the exhaust gas is electrolyzed. In addition, the hydrogen generator generates hydrogen from the other electrode (77) that is not in contact with the exhaust gas of the pair of electrodes. The hydrogen generator according to claim 1, wherein a catalyst is provided on at least one of the pair of electrodes (76, 77). A hydrogen generator (7) according to claim 1 or 2,
A fuel cell (12) for generating electrical energy by an electrochemical reaction between hydrogen and oxygen;
Hydrogen storage means (9) for storing hydrogen produced by the hydrogen generator (7);
A secondary battery (2) for supplying electric power necessary for starting the internal combustion engine (1);
An electric load (3) that consumes power when the internal combustion engine (1) is stopped and is supplied with power from the secondary battery (2) when the internal combustion engine (1) is stopped,
When the internal combustion engine (1) is stopped, the hydrogen storage means (9) supplies hydrogen to the fuel cell (12) to generate electric energy in the fuel cell (12), and this electric energy is converted into the secondary energy. A power generation system, characterized in that it is supplied to either the battery (2) or the electric load (3). The power generation system according to claim 3, further comprising voltage conversion means (16) for boosting the power generation voltage of the fuel cell (12). The power generation system according to claim 3 or 4, wherein the hydrogen storage means (9) includes a hydrogen storage alloy, and the hydrogen storage alloy stores hydrogen. The power generation system according to claim 3 or 4, wherein the hydrogen storage means is a high-pressure tank capable of storing high-pressure hydrogen.

Images