JP2004352543A - Hydrocarbon modification system and internal combustion engine equipped with hydrocarbon modification system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrocarbon modification system in which the capacity of a power source for pulse discharge is lowered by decreasing required discharge start voltage for generating pulse discharge in a gaseous mixture of the gaseous hydrocarbon with steam. <P>SOLUTION: In the hydrocarbon reforming system provided with: a gaseous mixture vessel housing the gaseous mixture containing the gaseous hydrocarbon and steam; the pulse power source outputting pulse like voltage; a pair of electrodes 5 and 6 to which the pulse like voltage outputted from the pulse power source is applied to cause pulse discharge in the gaseous mixture housed in the gaseous mixture vessel; and a negative pressure producing means for reducing the pressure in the gaseous mixture vessel to be below the atmospheric pressure to form a negative pressure state, the pulse discharge is carried out by applying the voltage from the pulse power source to the pair of the electrodes 5 and 6 after the pressure in the gaseous mixture vessel is reduced to a negative pressure equal to or below a prescribed pressure by the negative pressure producing means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydrocarbon reforming system that generates hydrogen by reforming a hydrocarbon-based fuel using discharge plasma, and more particularly to a hydrocarbon reforming system that uses the generated hydrogen as fuel for an internal combustion engine.
[0002]
[Prior art]
In a hydrocarbon reforming system that reforms hydrocarbon-based fuel to generate hydrogen, steam reforming called steam reforming is performed as a method of producing hydrogen or carbon monoxide by reacting hydrocarbon-based fuel with steam. Has been done. Therefore, by conducting a DC pulse discharge in a mixed gas obtained by gasifying a hydrocarbon-based fuel and mixing it with water vapor to cause chain hydrocarbons to react with water vapor, a low-temperature, low-pressure, and catalyst-free condition is used. A technique for generating hydrogen by using the method has been disclosed (for example, see Patent Document 1).
[0003]
In addition, as a technology that uses hydrogen generated by a hydrocarbon reformer, a fuel cell that generates hydrogen by converting hydrocarbon-based fuel into plasma using a pulse discharge device and generates an electromotive force by an electrochemical reaction with hydrogen is used. A fuel system for supplying the generated hydrogen has been disclosed (for example, see Patent Document 2).
[0004]
[Patent Document 1]
JP 2001-335302A
[Patent Document 2]
JP 2001-167784 A
[0005]
[Problems to be solved by the invention]
In a conventional hydrocarbon reforming system using pulse discharge, the pressure of an atmosphere in which a conversion reaction for converting hydrocarbons to hydrogen is performed, that is, an atmosphere in which a mixed gas of gaseous hydrocarbons and steam is placed, has a large pressure. It was at atmospheric pressure.
[0006]
Here, in order to generate a pulse discharge in the mixed gas, it is necessary to apply a high voltage equal to or higher than a predetermined voltage (hereinafter, referred to as “required discharge start voltage”) between the electrodes. However, as the pressure of the atmosphere in which the mixed gas in which the gaseous hydrocarbon and the steam are mixed is increased, the required discharge start voltage is increased. Therefore, if the pressure is in the atmospheric pressure state, the required discharge start voltage becomes relatively high, and there is a possibility that the capacity of the pulse power supply for applying the voltage to the electrodes increases.
[0007]
The present invention has been made in view of the above circumstances, and reduces the required discharge starting voltage for generating a pulse discharge in a mixed gas of a gaseous hydrocarbon and water vapor to lower the capacity of a pulse discharge power supply. It is an object of the present invention to provide a hydrocarbon reforming system that suppresses oil.
[0008]
[Means for Solving the Problems]
The present invention has focused on the pressure of an atmosphere in which a mixed gas of hydrocarbon gas and water vapor in which a conversion reaction from hydrocarbon to hydrogen is performed by pulse discharge is placed. This is because the required discharge starting voltage for generating the pulse discharge varies depending on the pressure.
[0009]
Therefore, a mixed gas container in which a mixed gas containing a hydrocarbon gas and water vapor is present, a pulse power supply that outputs a pulsed voltage, and a pulsed voltage output from the pulse power supply are applied, and the mixed gas container is applied to the mixed gas container. A pair of electrodes for generating a pulse discharge in the mixed gas contained therein, and negative pressure generating means for reducing the pressure in the mixed gas container from atmospheric pressure to a negative pressure state, and converting the hydrocarbon-based fuel to hydrogen In the hydrocarbon reforming system, a voltage is applied to the pair of electrodes by the pulse power source after the pressure in the mixed gas container is reduced to a predetermined pressure or less by the negative pressure generating means, thereby performing pulse discharge. By doing so, hydrocarbons in the mixed gas are converted into hydrogen.
[0010]
To obtain hydrogen by reforming a hydrocarbon-based fuel, the hydrocarbon-based fuel is vaporized into a hydrocarbon gas (hereinafter, the hydrocarbon gas is simply referred to as “hydrocarbon”), and then mixed with steam. A pulse discharge is caused in the mixed gas to generate plasma. The pulse discharge is generated by applying a pulse voltage to the pair of electrodes. Examples of the hydrocarbon-based fuel include fuels such as propane and butane composed of a single type of hydrocarbon, gasoline composed of a plurality of types of hydrocarbons, and the like.
[0011]
As the pulse discharge method for generating plasma in the mixed gas, a so-called glow discharge or arc discharge in which a pair of electrodes including a positive electrode and a negative electrode are provided in the mixed gas and a discharge is performed between the electrodes. Further, when the mixed gas container accommodating the mixed gas is made of an insulating material, electrodes may be provided inside and outside the mixed gas container, and pulse discharge may be performed between the electrodes. In such a discharge method, the amount of current flowing between the electrodes is small, and the conversion reaction is not efficiently performed. Therefore, in order to promote the conversion reaction, pulse discharge by a so-called packed bed system in which a photocatalyst, a high dielectric agent, or the like is filled in the mixed gas container is preferable. The pulse voltage applied to the pair of electrodes provided in the mixed gas container may be a DC pulse voltage or an AC pulse voltage.
[0012]
A pulsed discharge is generated by applying a pulsed voltage to the electrodes, but a voltage equal to or higher than the required discharge start voltage, which is a constant voltage to break through the insulating layer of air-fuel mixture or air existing between the electrodes and perform the discharge Must be applied to the electrodes. Here, the required discharge starting voltage has a physical property that increases as the pressure in the space where the discharge is performed, that is, the mixed gas container in which the mixed gas exists increases.
[0013]
Therefore, when performing the pulse discharge for the conversion reaction, the pressure in the mixed gas container is set to a negative pressure state equal to or lower than the atmospheric pressure and equal to or lower than the predetermined pressure by the negative pressure generating means, so that the internal pressure of the mixed gas container is reduced. The required discharge start voltage can be reduced as compared with the case where the pressure is in the atmospheric pressure state. As a result, the capacity of the pulse power supply can be reduced. Examples of the negative pressure generating means include a pump for sucking the inside of the mixed gas container.
[0014]
Further, the predetermined pressure is a pressure lower than the atmospheric pressure and a pressure in the mixed gas container that can be formed by the capacity of the pulse power supply and the negative pressure generating means. In other words, it is the pressure in the mixed gas container to be formed by the negative pressure generating means in order to lower the required discharge starting voltage within the range of the voltage applied to the electrode determined from the capacity of the pulse power supply.
[0015]
Here, once the pulse discharge is started in the mixed gas container, the voltage applied to the electrode from the pulse power source is set to a voltage relatively lower than the required discharge start voltage regardless of the pressure state in the mixed gas container. However, the pulse discharge is maintained. This is because once the pulse discharge is started, the mixed gas is turned into plasma, and the pulse discharge is maintained by its energy.
[0016]
Therefore, in the hydrocarbon reforming system, after the voltage is applied to the pair of electrodes by the pulse power source and the pulse discharge is started, the pressure in the mixed gas container is set to the negative pressure state by the negative pressure generating means. Is stopped, or the negative pressure state by the negative pressure generating means is reduced from that at the start of the pulse discharge. That is, after the required discharge starting voltage is reduced by the negative pressure generating means, the voltage applied to the electrodes to maintain the pulse discharge (hereinafter, referred to as “discharge sustaining voltage”) is reduced to the pressure in the mixed gas container. Regardless, since a relatively low voltage can be obtained, formation of a negative pressure state by the negative pressure generating means is stopped or the negative pressure state is reduced. As a result, energy consumed for forming the negative pressure state, for example, when the negative pressure generating means is a pump, drive loss by the pump can be reduced.
[0017]
Here, when the above-described hydrocarbon reforming system is provided in the internal combustion engine, hydrogen converted from hydrocarbon fuel by the hydrocarbon reforming system can be used as fuel for the internal combustion engine. Since hydrogen performs oxidative combustion more favorably than hydrocarbon-based fuels such as propane and gasoline, improvement in exhaust emission and improvement in fuel efficiency of an internal combustion engine are expected. When hydrogen generated by the hydrocarbon system is used as fuel for the internal combustion engine, it may be used as a part of the fuel, that is, in combination with fuel such as gasoline.
[0018]
Therefore, when the above-described hydrocarbon reforming system is provided in an internal combustion engine, the mixed gas container is connected to an intake system of the internal combustion engine, and the negative pressure generating unit operates the internal combustion engine when the internal combustion engine is driven. Then, the pressure in the mixed gas container is set to a negative pressure state by sucking the suction system.
[0019]
When the internal combustion engine is driven, the piston in the cylinder operates, and the intake air (air or the like) present in the intake pipe or the intake branch pipe, which is the intake system of the internal combustion engine, is sucked into the combustion chamber. Therefore, since the mixed gas container is connected to the intake system of the internal combustion engine, the inside of the mixed gas container is also sucked by the suction effect of driving the internal combustion engine. As a result, the inside of the mixed gas container can be brought into a negative pressure state without using a special facility such as a pump for creating a negative pressure state.
[0020]
In order to more efficiently suck the inside of the mixed gas container by driving the internal combustion engine, when the flow of intake air is restricted in the intake system of the internal combustion engine, that is, the flow of the intake system is shut off by a throttle valve or the like. Alternatively, it is preferable to perform the above-mentioned suction in the mixed gas container by driving the internal combustion engine when the operation state of the internal combustion engine is greatly restricted. Such operating states of the internal combustion engine include a motoring operation, a no-load operation, a light-load operation, and a deceleration operation.
[0021]
Next, in the internal combustion engine including the above-described hydrocarbon reforming system, a case where the internal combustion engine in the engine stopped state is started will be considered. Since the internal combustion engine is in an engine stopped state, the inside of the mixed gas container cannot be brought into a negative pressure state by driving the internal combustion engine. Therefore, when the internal combustion engine equipped with the above-described hydrocarbon reforming system is connected to an external drive device via an output shaft of the internal combustion engine, the negative pressure generating unit is configured to control the output shaft by the external drive device. After driving the internal combustion engine through and sucking the intake system to make the pressure in the mixed gas container a negative pressure state, and applying a voltage to the pair of electrodes by the pulse power source to perform a pulse discharge, The internal combustion engine is started.
[0022]
That is, by forcibly driving the internal combustion engine in the engine stopped state by the external drive device connected via the output shaft of the internal combustion engine, the inside of the mixed gas container driven by the internal combustion engine is sucked, It is possible to form a negative pressure state. At this time, the piston is driven by the external drive device without oxidizing and burning the fuel in the combustion chamber of the internal combustion engine. Here, as the external drive device, a starter motor for starting the internal combustion engine is exemplified. Further, when the internal combustion engine is an internal combustion engine in a so-called hybrid system provided together with another output device such as an electric motor, the electric motor can be used as the external drive device.
[0023]
Thereafter, when the pressure in the mixed gas container is reduced to a pressure at which pulse discharge can be generated, a conversion reaction from hydrocarbon to hydrogen is performed by pulse discharge. Then, the generated hydrogen is supplied as fuel to the internal combustion engine, and the internal combustion engine is started.
[0024]
With this configuration, it becomes possible to supply hydrogen to the internal combustion engine as fuel from the start of the engine of the internal combustion engine, so that good oxidizing combustion of the fuel is performed at the start of the engine. As a result, it is possible to improve the exhaust emission at the time of starting the engine, particularly at the time of the cold start, and to improve the exhaust emission even before the exhaust purification catalyst provided in the exhaust system of the internal combustion engine is activated. It becomes possible.
[0025]
Note that even when the hydrocarbon system is provided in the internal combustion engine, in order to form a negative pressure state by sucking the inside of the mixed gas container, not driving the internal combustion engine, but using external equipment separate from the internal combustion engine. A certain pump or the like may be used.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
<First embodiment>
Here, an embodiment of a hydrocarbon reforming system according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a hydrocarbon reforming system to which the present invention is applied.
[0027]
The hydrocarbon reforming system according to the present embodiment has a conversion reaction unit 1 in which pulse discharge is performed, and a pulse power supply unit 2 that supplies power for generating pulse discharge to the conversion reaction unit 1. . First, in the conversion reaction section 1, propane which is a hydrocarbon-based fuel stored in the fuel tank 3 is gasified and flows into the steam addition device 4. Then, the propane gasified by the steam addition device 4 and the steam are mixed, and the air-fuel mixture sequentially flows into the insulating tube 10 via the introduction tube 7. At this time, the flow of the air-fuel mixture in the introduction pipe 7 is adjusted by the opening of the flow control valve 15.
[0028]
A pair of electrodes 5 and 6 are provided inside the insulating tube 10. One electrode 5 is grounded, and the other electrode 6 is electrically connected to the pulse power supply 2. The pulse power supply unit 2 mainly includes a pulse signal generator 11 and a voltage generator 12. The pulse signal generator 11 is a device that outputs a DC pulse signal or an AC pulse signal. The pulse signal output from the pulse signal generator 11 is transmitted to the voltage generator 12 via the transmission line 14. The voltage generator 12 generates a pulsed high voltage based on the transmitted pulse signal, and transmits the high voltage to the electrode 6 via the transmission line 13.
[0029]
When the pulsed high voltage is transmitted to the electrode 6, a pulse discharge occurs between the electrode 5 and the electrode 6. By the pulse discharge, propane gas and water vapor forming an air-fuel mixture are converted into plasma, and recombined to be converted into hydrogen or carbon monoxide. Thereafter, the generated hydrogen and carbon monoxide are guided to the outside of the insulating tube 10 via the discharge tube 8. The generated hydrogen can be supplied as fuel for an internal combustion engine or supplied as fuel for power generation in a fuel cell.
[0030]
Here, when carbon monoxide is supplied to the fuel cell, the fuel cell has strong toxicity, and thus the deterioration of the fuel cell is promoted. Therefore, in order to separate hydrogen and carbon monoxide, hydrogen and carbon monoxide that have come out of the insulating tube 10 via the discharge tube 8 may be sent to a steam addition device (not shown).
[0031]
The steam addition device converts water into carbon dioxide by using a CO shift conversion reaction or a selective oxidation reaction by adding steam to generated carbon monoxide. This makes it possible to supply high-purity hydrogen to an internal combustion engine, a fuel cell, or the like.
[0032]
Further, a pump 17 is provided downstream of the discharge pipe 8 (when the generated hydrogen and carbon monoxide are sent to a steam addition apparatus, the steam addition apparatus) via a hydrogen discharge pipe 18. When the pump 17 is driven, the inside of the insulating tube 10 is sucked, and the pressure in the insulating tube 10 can be reduced to a pressure state lower than the atmospheric pressure, that is, a negative pressure state. Further, hydrogen generated by the pulse discharge in the insulating tube 10 is carried downstream of the pump 17.
[0033]
Here, the flow control valve 15 performs an opening / closing operation by a control signal from an electronic control unit (hereinafter, referred to as an ECU: Electronic Control Unit) 20. Further, the pulse power supply unit 2 and the pump 17 are electrically connected to the ECU 20, and the pulse power supply unit 2 applies a pulse-like voltage for pulse discharge to the electrode 6 according to a command from the ECU 20, and the pump 17 uses the insulating tube 10 Suction inside. Further, a pressure sensor 19 for detecting the pressure in the insulating pipe 10 is provided on the insulating pipe 10, and the pressure sensor 19 is electrically connected to the ECU 20 so that the ECU 20 can detect the pressure in the insulating pipe 10. It is.
[0034]
In the hydrocarbon reforming system configured as described above, control when a conversion reaction from hydrocarbon to hydrogen is performed by pulse discharge will be described with reference to FIG. FIG. 2 is a flowchart of pressure control in the insulating tube 10 during pulse discharge (negative pressure control during pulse discharge). This control is executed by the ECU 20.
[0035]
First, in S100, the flow control valve 15 is closed. Therefore, at this time, the mixed gas of propane and steam is not supplied into the insulating tube 10. When the process in S100 ends, the process proceeds to S101.
[0036]
In S101, the pump 17 is started and the inside of the insulating tube 10 is suctioned, so that the pressure state in the insulating tube 10 is reduced to a negative pressure state. When the process in S101 ends, the process proceeds to S102.
[0037]
In S102, the pressure Pi in the insulating tube 10 is detected by the pressure sensor 19. That is, a negative pressure state in the insulating tube 10 formed by the pump 17 is detected. When the process in S102 ends, the process proceeds to S103.
[0038]
In S103, it is determined whether or not the pipe pressure Pi detected in S102 is equal to or lower than a predetermined pressure P0. Here, the predetermined pressure P0 is a pressure lower than the atmospheric pressure, and a pump for reducing the required discharge start voltage within a range of the voltage applied to the electrode 6 determined from the capacity of the pulse power supply 2. Reference numeral 17 denotes a pressure in the insulating tube 10 to be formed. Therefore, in S103, when it is determined that the pipe pressure Pi detected in S102 is equal to or lower than the predetermined pressure P0, the pressure state in the insulating pipe 10 reduces the required discharge starting voltage for the pulse discharge. This means that the state is a sufficiently negative pressure state, and the process proceeds to S104. On the other hand, when it is determined in S103 that the pipe pressure Pi detected in S102 is higher than the predetermined pressure P0, the pressure state in the insulating pipe 10 is required to reduce the required discharge starting voltage for pulse discharge. This means that the state is not sufficiently negative, and the processing after S102 is performed again so that the pump 17 suctions the inside of the insulating tube 10.
[0039]
In S104, since the pressure state in the insulating pipe 10 is sufficiently negative, the flow control valve 15 is opened to introduce the mixed gas into the insulating pipe 10, and the pulse power supply unit 2 Pulse discharge is performed by applying a pulse-like voltage to 6. As a result, a conversion reaction from hydrocarbon to hydrogen occurs, and hydrogen and carbon monoxide are generated. The generated hydrogen and carbon monoxide flow to the discharge pipe 8 and the hydrogen discharge pipe 18. When the process of S104 ends, the process proceeds to S105.
[0040]
In S105, the driving of the pump 17 is stopped or the pump rotation speed is reduced. When the driving of the pump 17 is stopped, the pressure state in the insulating pipe 10 changes from the negative pressure state to the atmospheric pressure state, and the negative pressure state in the insulating pipe 10 is reduced by reducing the pump rotation speed of the pump 17. It becomes a negative pressure state close to the atmospheric pressure. This control ends when the process of S105 ends.
[0041]
According to this control, when starting the pulse discharge for causing a conversion reaction from hydrocarbon to hydrogen, the pressure state in the insulating tube 10 is set to a negative pressure state lower than the atmospheric pressure or the like, so that the pulse discharge at the start of the pulse discharge is started. The required discharge start voltage can be reduced. Thus, the capacity of the pulse power supply unit can be reduced. Further, since the discharge sustaining voltage for maintaining the pulse discharge is relatively low regardless of the pressure state in the insulating tube 10, once the pulse discharge is started, the pressure state in the insulating tube 10 is changed to a high negative pressure state. You do not need to keep it. Therefore, after the start of the pulse discharge, the driving of the pump is stopped or the negative pressure forming ability is reduced, so that the energy consumed for driving the pump can be reduced.
[0042]
In this control, the pressure in the insulating pipe 10 is detected by the pressure sensor 19, but instead, the pressure in the insulating pipe 10 is estimated based on the driving time of the pump 17, and based on the estimated pressure. The start of the pulse discharge may be determined. Note that the relationship between the drive time of the pump 17 and the pressure in the insulating tube 10 may be determined in advance by experiments or the like.
[0043]
<Second embodiment>
Next, another embodiment for lowering the required discharge start voltage at the start of pulse discharge will be described with reference to FIG. FIG. 3 is a diagram illustrating a schematic configuration of a hydrocarbon reforming system to which the present invention is applied and an internal combustion engine including the hydrocarbon reforming system. The hydrocarbon reforming system shown in FIG. 3 is a modification of the hydrocarbon reforming system shown in FIG. Therefore, the same components are denoted by the same reference numerals, and description thereof will be omitted.
[0044]
In the hydrocarbon reforming system shown in FIG. 3, the hydrogen discharge passage 18 is connected to the intake system 21 of the internal combustion engine 22 instead of the pump 17 in the hydrocarbon reforming system shown in FIG. The intake system 21 is an intake pipe, an intake branch pipe, or the like in the internal combustion engine 22, and is a portion in which intake air that is sucked into a combustion chamber of the internal combustion engine 22 by a piston that operates by driving the internal combustion engine 1 exists.
[0045]
In the hydrocarbon reforming system and the internal combustion engine configured as described above, the inside of the insulating pipe 10 is sucked by the suction of the intake air into the combustion chamber by the driving of the internal combustion engine, so that the pressure state in the insulating pipe 10 becomes negative. It is possible to be in a pressure state.
[0046]
Here, when the intake system 21 is provided with an intake throttle valve for restricting the amount of intake air flowing through the intake system 21, when the internal combustion engine is driven to form a negative pressure state in the insulating pipe 10, By closing the throttle valve or reducing its opening degree, it is possible to more efficiently form the negative pressure state. In such a case, since the amount of intake air supplied to the internal combustion engine 22 is reduced, it is preferable to perform the operation during the operation state of the internal combustion engine 22 which has little influence on the oxidizing combustion of fuel in the internal combustion engine 22. For example, during a motoring operation with a small engine load on the internal combustion engine 22, during a no-load operation or a light-load operation, or a deceleration operation in which fuel supplied to the internal combustion engine 22 is limited to reduce the engine rotation speed of the internal combustion engine. At times, the pressure state in the insulating tube 10 can be more efficiently set to the negative pressure state.
[0047]
Therefore, also in the internal combustion engine 22 including the hydrocarbon reforming system shown in FIG. 3, by performing suction by driving the internal combustion engine instead of suction by the pump shown in FIG. 1, negative pressure during pulse discharge as shown in FIG. Pressure control can be performed. However, since the hydrogen generated by the hydrocarbon reforming system is supplied to the internal combustion engine 22 as fuel for the internal combustion engine 22 or as a part of the fuel, the driving of the internal combustion engine 22 is not stopped after the start of the pulse discharge. .
[0048]
As a result, even in the internal combustion engine 22 including the hydrocarbon reforming system shown in FIG. 3, when starting the pulse discharge for causing the conversion reaction from hydrocarbon to hydrogen, the pressure state in the insulating tube 10 is changed to the atmospheric pressure. By setting a lower negative pressure state or the like, the required discharge start voltage at the start of pulse discharge can be reduced. Thus, the capacity of the pulse power supply unit 2 can be reduced. Further, another equipment such as a pump for creating a negative pressure state is not required. Further, by using the hydrogen generated by the conversion reaction as a fuel of the internal combustion engine 22 or as a part of the fuel, improvement in exhaust emission and improvement in fuel efficiency of the internal combustion engine 22 are expected.
[0049]
<Third embodiment>
Next, an embodiment for lowering the required discharge start voltage at the start of pulse discharge when starting the internal combustion engine in the engine stopped state will be described with reference to FIG. FIG. 4 is a diagram illustrating a schematic configuration of a hydrocarbon reforming system to which the present invention is applied and an internal combustion engine including the hydrocarbon reforming system. The hydrocarbon reforming system shown in FIG. 4 is a modification of the hydrocarbon reforming system shown in FIGS. 1 and 4. Therefore, the same components are denoted by the same reference numerals, and description thereof will be omitted.
[0050]
The internal combustion engine 22 including the hydrocarbon reforming system shown in FIG. 4 is connected to an electric motor 24 which is another external drive device from the internal combustion engine 22 via a transmission switching device 23. That is, the internal combustion engine 22 and the electric motor 24 constitute a so-called hybrid system. Here, the electric motor 24 is driven by receiving power supply from a battery (not shown). The transmission switching device 23 transmits the driving force of the electric motor 24 to the outside according to a command from the ECU 20. On the other hand, when the internal combustion engine 22 is in the engine stopped state, that is, in a state where the engine is stopped without oxidizing and burning fuel in the internal combustion engine 22, the driving force is transmitted to the internal combustion engine 22 to transmit the driving force to the internal combustion engine 22. Can be forcibly driven.
[0051]
In the hydrocarbon reforming system and the internal combustion engine configured as described above, even when the internal combustion engine is in the engine stop state, the internal combustion engine 22 is forcibly driven by the electric motor 24 to achieve the second embodiment described above. Similarly, it is possible to suck the inside of the insulating tube 10 and change the pressure state inside the insulating tube 10 to a negative pressure state. Further, since the internal combustion engine 22 is in the engine stopped state, the internal combustion engine 22 is not burning fuel. Therefore, when the intake system 21 is provided with an intake throttle valve, it is preferable to close the intake throttle valve or reduce the opening thereof, as in the case of the above-described second embodiment.
[0052]
Therefore, even in the internal combustion engine equipped with the hydrocarbon reforming system shown in FIG. 4, the negative pressure control during pulse discharge as shown in FIG. 2 is performed by performing suction by driving the internal combustion engine instead of suction by the pump. Is possible. However, the hydrogen generated by the hydrocarbon reforming system is supplied to the internal combustion engine 22 as fuel for starting the internal combustion engine 22 in an engine stopped state or as a part of the fuel. Is started.
[0053]
As a result, in the internal combustion engine 22 including the hydrocarbon reforming system shown in FIG. 4, when starting the pulse discharge for causing the conversion reaction from hydrocarbon to hydrogen, the pressure state in the insulating tube 10 is changed from the atmospheric pressure to the atmospheric pressure. By setting a low negative pressure state or the like, it becomes possible to lower the required discharge start voltage at the start of pulse discharge. Thus, the capacity of the pulse power supply unit 2 can be reduced. Further, another equipment such as a pump for creating a negative pressure state is not required. Further, by starting the engine of the internal combustion engine 22 using the hydrogen generated by the conversion reaction as a fuel of the internal combustion engine 22 or as a part of the fuel, it is expected that the exhaust emission at the time of starting the engine is improved. Further, it is possible to improve the exhaust emission even before the exhaust purification catalyst provided in the exhaust system of the internal combustion engine is activated.
[0054]
In the present embodiment, in the hybrid system, the internal combustion engine 22 is forcibly driven by the electric motor 24 which is an external output device different from the internal combustion engine 22. By forcibly driving the internal combustion engine by a starter motor used at the time of starting the engine, the pressure state in the insulating pipe can be set to a negative pressure state.
[0055]
【The invention's effect】
As described above, the hydrocarbon reforming system according to the present invention and the internal combustion engine including the hydrocarbon reforming system, when starting pulse discharge in a mixed gas of gaseous hydrocarbon and steam, start the pulse discharge. By reducing the pressure of the atmosphere in which the mixed gas is placed and setting it in a negative pressure state, the required discharge start voltage for generating pulse discharge can be reduced, and the capacity of the pulse discharge power supply can be reduced. It becomes.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of a hydrocarbon reforming system according to an embodiment of the present invention.
FIG. 2 is a flowchart of control for setting a pressure state in an insulating tube to a negative pressure at the time of pulse discharge in the hydrocarbon reforming system according to the embodiment of the present invention.
FIG. 3 is a block diagram illustrating a schematic configuration of a hydrocarbon reforming system according to the embodiment of the present invention and an internal combustion engine including the hydrocarbon reforming system.
FIG. 4 is a second block diagram illustrating a schematic configuration of a hydrocarbon reforming system according to the embodiment of the present invention and an internal combustion engine including the hydrocarbon reforming system.
[Explanation of symbols]
1 ··· Conversion conversion section
2 .... Pulse power supply
3. Fuel tank
5 ... Electrode
6 Electrodes
10 Insulating tube
11 ... Pulse signal generator
12. Voltage generator
15 ... Flow control valve
17. Pump
20 ... ECU
21 ... Intake system of internal combustion engine
22 ... Internal combustion engine
24 ... Electric motor

Claims (5)

A mixed gas container containing a mixed gas containing a hydrocarbon gas and water vapor,
A pulse power supply that outputs a pulsed voltage,
A pair of electrodes, to which a pulse-like voltage output from the pulse power source is applied and which causes a pulse discharge in the mixed gas contained in the mixed gas container,
Negative pressure generating means for reducing the pressure in the mixed gas container from atmospheric pressure to a negative pressure state,
After the pressure in the mixed gas container is reduced to a predetermined pressure or less by the negative pressure generating means, a voltage is applied to the pair of electrodes by the pulse power supply to perform a pulse discharge, whereby the mixed gas A hydrocarbon reforming system characterized by converting hydrocarbons into hydrogen. After applying a voltage to the pair of electrodes by the pulse power supply and starting a pulse discharge, the negative pressure generating means stops making the pressure in the mixed gas container a negative pressure state. Item 4. A hydrocarbon reforming system according to Item 1. The method according to claim 1, wherein after the pulse power supply applies a voltage to the pair of electrodes to start a pulse discharge, a negative pressure state of the pressure in the mixed gas container by the negative pressure generating means is reduced. A hydrocarbon reforming system as described. When the hydrocarbon reforming system is provided in an internal combustion engine,
The mixed gas container is connected to an intake system of the internal combustion engine,
2. The hydrocarbon reforming device according to claim 1, wherein the negative pressure generating unit sets the pressure in the mixed gas container to a negative pressure state by driving the internal combustion engine to suck the intake system. 3. Internal combustion engine with quality system. When the internal combustion engine is connected to an external drive device via an output shaft of the internal combustion engine,
The negative pressure generating means drives the internal combustion engine through the output shaft by the external drive device and sucks the intake system to make the pressure in the mixed gas container a negative pressure state,
The internal combustion engine according to claim 4, wherein the internal combustion engine is started after applying a voltage to the pair of electrodes by the pulse power supply to perform a pulse discharge.

Images