JP6244982B2 - Gas reformer and reducing agent addition device - Google Patents

Description

  The present invention relates to a gas reformer that reforms a gas by electric discharge, and a reducing agent addition device that includes the gas reformer.

  2. Description of the Related Art Conventionally, there is known a gas reforming apparatus that reforms a gas existing in a discharge region by discharging between a pair of electrode plates. Specific examples of the use of this apparatus include a use for reforming a reducing agent for reducing NOx contained in exhaust gas of an internal combustion engine, or a method for modifying oxygen gas into ozone.

  Now, in this type of apparatus, a phenomenon in which foreign matter adheres to and accumulates on the electrode plate is likely to occur. In response to this concern, the apparatus described in Patent Document 1 heats and removes the accumulated foreign matter using an electric heater.

JP 2006-122849 A

  Now, the present inventors have examined a configuration in which a linear electrode (electrode wire) is employed instead of the plate-like electrode and the electrode wire is covered with a dielectric film. According to the apparatus by this examination, the effects of “electric field concentration” and “creeping discharge” described below are exhibited, and the gas reforming ability can be improved.

  That is, since the linear electrode is adopted, the electric field in the discharge region is concentrated in the vicinity of the electrode line. Then, a discharge (seed discharge) is generated starting from the portion where the electric field is concentrated in this way, and the discharge is easily induced in the portion where the electrolysis is not concentrated due to the seed discharge. Therefore, the discharge in the discharge region can be stably generated without increasing the voltage applied to the electrode plate.

  Further, since the electrode wire is covered with the dielectric film, creeping discharge is generated in which the discharged electrons move along the surface of the dielectric film. Then, the chance of the discharged electrons coming into contact with the gas to be reformed increases, so that the gas reforming rate is improved.

  However, when the electric heater described in Patent Document 1 is arranged in the discharge region in the apparatus according to the above examination to attempt to burn and remove foreign substances, the electric field concentration and creeping discharge described above are inhibited by the electric heater, and the gas reforming capability Improvement is hindered.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas reforming apparatus that enables combustion removal of accumulated foreign matters without hindering improvement in gas reforming ability by using an electrode wire. Another object is to provide an apparatus for adding a reducing agent.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later, and do not limit the technical scope of the invention. .

One of the disclosed inventions is an electrode plate having a linearly extending electrode line (25) and a dielectric film (26) covering the electrode line, and at least a pair of gas reforming by discharge from the electrode line. Electrode plates (21, 21B) and a heater (24) that generates heat by power feeding to heat the electrode plates. And the heater is disposed outside the discharge region between the electrode wire of one of the pair of electrode plates and the electrode wire of the other electrode plate ,
Three or more electrode plates are arranged in a predetermined direction,
A predetermined electrode plate among the three or more electrode plates is referred to as a first electrode plate, and an electrode plate disposed on one side of the first electrode plate is referred to as a second electrode plate. The electrode plate disposed opposite to the other side is called the third electrode plate,
The dielectric film of the first electrode plate is provided on both sides of the first electrode plate,
Two electrode wires of the first electrode plate are provided between the dielectric films disposed on both sides of the first electrode plate,
Of the two electrode lines of the first electrode plate, the electrode line located on the second electrode plate side forms a discharge region with the electrode line of the second electrode plate,
Of the two electrode lines of the first electrode plate, the electrode line located on the third electrode plate side forms a discharge region with the electrode line of the third electrode plate,
The heater for heating the first electrode plate is arranged between two electrode wires provided on the first electrode plate .

  According to the present invention, the heater is disposed outside the discharge region. Therefore, it is possible to avoid the effect of electric field concentration by adopting a linear electrode line and the effect of creeping discharge by covering the electrode line with a dielectric film being hindered by the heater. Therefore, it is possible to remove foreign matters deposited on the electrode plate without hindering improvement in gas reforming ability due to these effects.

The disclosed gas reforming apparatus is an electrode plate having a linearly extending electrode wire (25) and a dielectric film (26) covering the electrode wire, and reforms the gas by discharge from the electrode wire. At least a pair of electrode plates (21C) to be discharged, a discharge power supply circuit (84) for applying an alternating or pulsed voltage to the electrode wires so as to cause a discharge in the pair of electrode plates, and the electrode wires to function as heaters And a heater power supply circuit (82) for applying a DC voltage to the electrode wire.

According to this gas reforming apparatus , since the discharge electrode wire also functions as a heater, it is not necessary to provide a heater separately from the electrode wire. Therefore, the problem of providing a heater separately from the electrode wire, that is, “the effect of electric field concentration by adopting a linear electrode wire and the effect of creeping discharge by covering the electrode wire with a dielectric film are hindered by the heater. Can be eliminated. Therefore, it is possible to remove foreign matters deposited on the electrode plate without hindering improvement in gas reforming ability due to these effects.

The figure which shows the combustion system to which the reducing agent addition apparatus which concerns on 1st Embodiment of this invention, and the reducing agent addition apparatus are applied. Sectional drawing which shows typically the discharge reactor (gas reforming apparatus) shown in FIG. The enlarged view which shows typically the cross section which follows the dashed-dotted line III part of FIG. 2, and the III-III line of FIG. The perspective view which shows the electrode plate of FIG. 3 typically. The top view which shows the positional relationship of the heat generating element of FIG. 4, and an electrode wire. The top view which shows the shape of the heat generating element of FIG. The top view which shows the shape of the electrode wire of FIG. The electric block diagram which shows the electric power feeding circuit for discharge which concerns on 1st Embodiment, and the electric power feeding circuit for heaters. The flowchart which shows the procedure of the heating control which concerns on 1st Embodiment. The figure explaining the implementation time of the heating control shown in FIG. The flowchart which shows the procedure of heating control in 2nd Embodiment of this invention. The top view which shows the positional relationship of a heat generating element and an electrode wire in 3rd Embodiment of this invention. The top view which shows the shape of the heat generating element of FIG. The top view which shows the shape of the electrode wire of FIG. Sectional drawing which shows typically a discharge reactor (gas reforming apparatus) in 4th Embodiment of this invention. The figure explaining the operation state at the time of discharge control by the discharge reactor of FIG. The figure explaining the operation state at the time of heating control by the discharge reactor of FIG. The figure which shows the combustion system to which the reducing agent addition apparatus which concerns on 5th Embodiment of this invention, and the reducing agent addition apparatus are applied.

  Hereinafter, a plurality of modes for carrying out the invention will be described with reference to the drawings. In each embodiment, portions corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals and redundant description may be omitted. In each embodiment, when only a part of the configuration is described, the other configurations described above can be applied to other portions of the configuration.

(First embodiment)
The combustion system shown in FIG. 1 includes an internal combustion engine 10, a supercharger 11, a particulate collection device (DPF 14), a DPF regeneration device (regeneration DOC 14 a), a NOx purification device 15, a reducing agent purification device (purification). DOC16) and a reducing agent adding device A1. The combustion system is mounted on a vehicle, and the vehicle travels using the output of the internal combustion engine 10 as a drive source. The internal combustion engine 10 is a compression self-ignition diesel engine, and light oil is used as a fuel for combustion.

  The supercharger 11 includes a turbine 11a, a rotating shaft 11b, and a compressor 11c. The turbine 11a is disposed in the exhaust passage 10ex of the internal combustion engine 10 and rotates by the kinetic energy of the exhaust. The rotating shaft 11b couples the impellers of the turbine 11a and the compressor 11c to transmit the rotational force of the turbine 11a to the compressor 11c. The compressor 11c is disposed in the intake passage 10in of the internal combustion engine 10, compresses the intake air, and supercharges the internal combustion engine 10.

  A cooler 12 for cooling the intake air compressed by the compressor 11c is disposed on the downstream side of the compressor 11c in the intake passage 10in. The compressed intake air cooled by the cooler 12 is adjusted in flow rate by a throttle valve 13 and then distributed to a plurality of combustion chambers of the internal combustion engine 10 by an intake manifold.

  A regeneration DOC 14a (Diesel Oxidation Catalyst), a DPF 14 (Diesel Particulate Filter), a NOx purification device 15, and a purification DOC 16 are arranged in this order on the downstream side of the turbine 11a in the exhaust passage 10ex. The DPF 14 collects fine particles contained in the exhaust. The regeneration DOC 14a has a catalyst that oxidizes and burns unburned fuel in the exhaust. Due to this combustion, the fine particles collected by the DPF 14 are burned, and the DPF 14 is regenerated to maintain the collection ability. Note that combustion by supplying unburned fuel to the regeneration DOC 14a is not always performed, but temporarily performed at a time when regeneration is necessary.

  A supply pipe 32 of the reducing agent adding device A1 is connected to the downstream side of the DPF 14 and the upstream side of the NOx purification device 15 in the exhaust passage 10ex. The reformed fuel generated by the reducing agent adding device A1 is added as a reducing agent from the supply pipe 32 to the exhaust passage 10ex. The reformed fuel is obtained by partially oxidizing a hydrocarbon (fuel) used as a reducing agent and reforming it into a partially oxidized hydrocarbon such as an aldehyde, which will be described in detail later.

The NOx purification device 15 includes a honeycomb-shaped carrier 15b that carries a reduction catalyst, and a housing 15a that houses the carrier 15b. The NOx purification device 15 purifies NOx contained in the exhaust by reacting NOx in the exhaust with the reformed fuel on the reduction catalyst and reducing it to N ₂ . Although exhaust gas contains O ₂ in addition to NOx, the reformed fuel reacts selectively with NOx in the presence of O ₂ .

  A reduction catalyst having a function of adsorbing NOx is used. Specifically, when the catalyst temperature is lower than the activation temperature at which the reduction reaction is possible, the reduction catalyst exhibits a function of adsorbing NOx in the exhaust. When the catalyst temperature is equal to or higher than the activation temperature, the adsorbed NOx is reduced by the reformed fuel and released from the reduction catalyst. For example, the NOx purification device 15 having a NOx adsorption function is provided by a reduction catalyst made of silver alumina supported on the carrier 15b.

  The purification DOC 16 is configured by accommodating a carrier carrying an oxidation catalyst in a housing. The purification DOC 16 oxidizes the reducing agent that has not been used for NOx reduction on the reduction catalyst and has flowed out of the NOx purification device 15 on the oxidation catalyst. This prevents the reducing agent from being released into the atmosphere from the outlet of the exhaust passage 10ex. Note that the activation temperature of the oxidation catalyst (eg, 200 ° C.) is lower than the activation temperature of the reduction catalyst (eg, 250 ° C.).

  Next, the reducing agent adding device A1 that generates reformed fuel and adds it to the exhaust passage 10ex from the supply pipe 32 will be described. The reducing agent addition apparatus A1 includes a discharge reactor 20 (gas reforming apparatus), an air pump 20p, a reaction vessel 30, a fuel injection valve 40, and a fuel heating heater 50, which will be described in detail below.

  The discharge reactor 20 includes a housing 22 that forms a flow passage 22a therein, and a plurality of electrode plates 21 are arranged in a predetermined direction (vertical direction in FIG. 2) in the flow passage 22a. Specifically, as shown in FIG. 2, a plurality of electrode plates 21 are held in the housing 22 via an electrical insulating member 23. These electrode plates 21 have a flat plate shape arranged so as to face each other in parallel. An electrode plate to which a high voltage is applied (applied electrode plate) and a grounded electrode plate (ground electrode plate) are provided. Alternatingly arranged. The voltage application to the electrode plate 21 is controlled by a microcomputer (microcomputer 81) provided in the electronic control unit (ECU 80). The detailed structure of the electrode plate 21 will be described later in detail with reference to FIGS.

  The air blown by the air pump 20p flows into the housing 22 of the discharge reactor 20. The air pump 20p is driven by an electric motor, and the electric motor is controlled by the microcomputer 81. The air blown by the air pump 20 p flows into the flow passage 22 a in the housing 22 and flows through the interelectrode passage 21 a that is a passage between the electrode plates 21.

  At the downstream side of the discharge reactor 20, a reaction vessel 30 that forms a reaction chamber 30a is attached. In the reaction chamber 30a, the fuel and air are mixed, and the fuel is oxidized by oxygen in the air. The air flowing through the interelectrode passage 21 a and flowing in from the air inlet 30 c flows into the reaction chamber 30 a and then jets out from the jet port 30 b formed in the reaction vessel 30. The ejection port 30 b communicates with the supply pipe 32.

  A fuel injection valve 40 is attached to the reaction vessel 30. The liquid fuel in the fuel tank 40t is supplied to the fuel injection valve 40 by the pump 40p, and is injected from the injection hole (not shown) of the fuel injection valve 40 into the reaction chamber 30a. The fuel in the fuel tank 40t is also used as the combustion fuel described above, and the fuel used for combustion of the internal combustion engine 10 and the fuel used as the reducing agent are shared. The fuel injection valve 40 is configured to open by an electromagnetic force generated by an electromagnetic solenoid, and power supply to the electromagnetic solenoid is controlled by the microcomputer 81.

  A fuel heater 50 that generates heat when energized is attached to the reaction vessel 30, and the energized state of the fuel heater 50 is controlled by the microcomputer 81. The heating surface of the fuel heater 50 is disposed in the reaction chamber 30a, and heats the liquid fuel injected from the fuel injection valve 40. The fuel injection valve 40 is located above the heat generating surface of the fuel heater 50. The liquid fuel injected from the fuel injection valve 40 adheres to the heat generating surface and is heated and vaporized by the fuel heater 50. Further, the vaporized fuel is heated to a predetermined temperature or higher by the fuel heater 50. As a result, cracking in which the fuel is decomposed into hydrocarbons having a small number of carbon atoms occurs in the reaction chamber 30a.

  A temperature sensor 31 for detecting the temperature of the reaction chamber 30 a is attached to the reaction vessel 30. Specifically, the temperature sensor 31 is disposed in the reaction chamber 30 a above the heat generating surface of the fuel heater 50. The temperature detected by the temperature sensor 31 is the temperature after the reaction between the vaporized fuel and air. The temperature sensor 31 outputs detected temperature information (detected temperature) to the ECU 80.

  When the discharge reactor 20 is energized, electrons emitted from the electrode plate 21 collide with oxygen molecules contained in the air in the interelectrode passage 21a. Then, ozone is generated from oxygen molecules. That is, the discharge reactor 20 generates oxygen as active oxygen by bringing oxygen molecules into a plasma state by dielectric barrier discharge. Accordingly, the air flowing into the reaction chamber 30a contains ozone generated in the discharge reactor 20.

  In the reaction chamber 30a, a cold flame reaction occurs in which the gaseous fuel is partially oxidized by oxygen or ozone in the air. Such a partially oxidized fuel is called a reformed fuel. As a specific example of the reformed fuel, a partial oxide in a state where a part of the fuel (hydrocarbon compound) is oxidized to an aldehyde group (CHO) ( For example, aldehyde). When the ozone generated in the discharge reactor 20 is contained in the air, the fuel oxidation reaction rate in the reaction chamber 30a is increased.

  Here, the fuel in the high temperature environment oxidizes and reacts with oxygen contained in the surrounding air even if it is atmospheric pressure, and self-ignition combustion. Such an oxidation reaction by self-ignition combustion is also called a hot flame reaction in which carbon dioxide and water are generated while generating heat. However, when the ratio of fuel to air (equivalent ratio) and the ambient temperature are within a predetermined range, the period of staying in the cold flame reaction described below becomes longer, and then a hot flame reaction occurs. That is, an oxidation reaction occurs in two stages, a cold flame reaction and a hot flame reaction.

  This cold flame reaction is a reaction that easily occurs when the ambient temperature is low and the equivalence ratio is small, and is a reaction in which the fuel is partially oxidized by oxygen contained in the surrounding air. Then, when the ambient temperature rises due to heat generated by the cold flame reaction and then a certain period of time elapses, the partially oxidized fuel (for example, aldehyde) is oxidized and the above-described hot flame reaction occurs. Therefore, if the fuel stays in the reaction chamber 30a for a long time, a cold flame reaction occurs in the reaction chamber 30a and then a hot flame reaction also occurs.

  In the present embodiment, the atmospheric temperature, the equivalence ratio, and the fuel residence time in the reaction chamber 30a are adjusted so that the cold flame reaction occurs but the hot flame reaction does not occur. Further, by using a partially oxidized fuel such as aldehyde generated by the cold flame reaction as a reducing agent for NOx purification, the NOx purification rate by the NOx purification device 15 can be improved. Further, the higher the concentration of ozone contained in the air flowing into the reaction chamber 30a, the more the fuel oxidation reaction is promoted, and the start timing of the cold flame reaction is advanced. Therefore, by generating a sufficient amount of ozone by the discharge reactor 20, it is possible to reduce the amount of fuel that flows out of the reaction chamber 30a without being reformed into aldehyde or the like.

  As shown in FIG. 3, the electrode plate 21 includes a heater 24, an electrode wire 25, and a dielectric film 26. The heater 24 is configured by accommodating a heating element 24b inside a ceramic plate 24a. Electrode wires 25 are provided on both surfaces of the heater 24, and a dielectric film 26 that covers the electrode wires 25 is provided on both surfaces of the heater 24. Specifically, the electrode lines 25 are printed in a pattern shown in FIG. 4 on both surfaces of the ceramic plate 24a. The entire surfaces of the ceramic plate 24 a are covered with a dielectric film 26 so as to enclose the printed electrode lines 25.

  In FIG. 3, since the cross-sectional area of the electrode wire 25 is schematically exaggerated, the space is shown between the dielectric film 26 and the ceramic plate 24a. However, in reality, such a space does not exist, and the dielectric film 26 is in close contact with the ceramic plate 24 a in a state of including the electrode wire 25.

  Of the three electrode plates 21 shown in FIG. 3, the electrode plate 21 located at the center is the above-described application electrode plate, and the electrode plates 21 located above and below the application electrode plate are the above-described ground electrode plates. An alternating voltage is applied to the two electrode lines 25 of the application electrode plate. The two electrode lines 25 included in the ground electrode plate are both grounded. That is, the two electrode lines 25 provided in the same electrode plate 21 have the same potential. The application electrode plate corresponds to the first electrode plate recited in the claims, the ground electrode above the first electrode plate is the second electrode plate, and the ground electrode above the first electrode plate is the third electrode. It corresponds to an electrode plate.

  Of the two electrode lines 25 included in the first electrode plate, the electrode line 25 positioned on the second electrode plate side, and the electrode positioned on the first electrode plate side among the two electrode lines 25 included in the second electrode plate. A discharge region is formed with the line 25. Similarly, of the two electrode lines 25 included in the first electrode plate, the electrode line 25 located on the third electrode plate side, and the two electrode lines 25 included in the third electrode plate on the first electrode plate side. A discharge region is formed between the electrode line 25 and the electrode line 25.

  That is, the interelectrode passage 21a becomes a discharge region, and electrons emitted from the electrode lines 25 of the second and third electrode plates move toward the first electrode plate through the interelectrode passage 21a (dotted arrow in FIG. 3). reference). The electrons moving in this way collide with oxygen molecules present in the interelectrode passage 21a, thereby generating ozone. As described above, an AC voltage is applied to the first electrode plate. For this reason, when the applied voltage to the first electrode plate is positive, discharge is performed in the direction of the dotted arrow in FIG. 3, and when the applied voltage to the first electrode plate is negative, the direction of discharge is reversed. That is, electrons emitted from the electrode line 25 of the first electrode plate move toward the second and third electrode plates through the interelectrode passage 21a.

  Here, contrary to the present embodiment, when a plate-like electrode is used instead of the electrode wire 25, the intensity distribution of the electric field generated in the interelectrode passage 21a (discharge region) becomes uniform. On the other hand, in the present embodiment, since the linear electrode line 25 is employed, the electric field generated in the interelectrode passage 21 a is concentrated on the electrode line 25. In the interelectrode passage 21a, discharge (seed discharge) is generated starting from the portion where the electric field is concentrated in this way, and the discharge is easily induced in the portion where electrolysis is not concentrated due to the seed discharge. Therefore, discharge in the discharge region can be stably generated without increasing the voltage applied to the electrode wire 25.

  Furthermore, in this embodiment, since the dielectric film 26 covering the electrode line 25 is provided, as shown by the dotted arrow in FIG. 3, the electrons moved toward the first electrode plate are the dielectric film of the first electrode plate. Thus, creeping discharge such as movement along the surface of 26 occurs. Then, since the opportunity for the discharged electrons to come into contact with oxygen present in the interelectrode passage 21a is increased, the rate of reforming oxygen into ozone (reforming rate) is improved.

  As shown in FIG. 4, the electrode wires 25 and the heating elements 24b are linearly extending so as to be distributed over the entire ceramic plate 24a. As shown in FIG. 5, the ceramic plate 24 a is provided with terminals 24 t and 24 u for supplying power to the heating element 24 b and a terminal 25 t for supplying power to the electrode wire 25. A DC voltage (for example, 12V) from the in-vehicle battery B (see FIG. 8) is applied to the terminal 24t, and the terminal 24u is grounded. An AC voltage is applied to the terminal 25t.

  As shown in FIG. 3, the heat generating element 24b is disposed so as to extend along the second virtual plane inside the ceramic plate 24a. Further, as shown in FIG. 6, the heating element 24b is arranged to meander and extend.

  Specifically, one heating element 24b has a plurality of long portions and a plurality of short portions described below. The longitudinal portion includes dotted line portions indicated by symbols H1 and H2 in FIG. The longitudinal portion has a shape extending in the air flow direction (left-right direction in FIG. 5), and a plurality of longitudinal portions are arranged in a direction perpendicular to the air flow direction (up-down direction in FIG. 5). On the other hand, the short part extends in a direction perpendicular to the air flow direction, and has a shape that connects the ends of adjacent long parts. The short portion includes dotted line portions indicated by symbols H3, H4, H5, H6, H7, H8, and H9 in FIG.

  As shown in FIG. 3, the electrode line 25 is disposed so as to extend along the surface (first virtual plane) of the ceramic plate 24 a. Moreover, as shown in FIG. 7, the electrode wire 25 is arranged so as to extend in a branched manner. The first virtual plane is a plane that extends in parallel to the second virtual plane.

  Specifically, the electrode wire 25 has a plurality of short portions and a plurality of long portions described below. The longitudinal portion has a shape extending in a direction (vertical direction in FIG. 5) perpendicular to the air flow direction, and a plurality of the longitudinal portions are arranged in the air flow direction (horizontal direction in FIG. 5). The longitudinal portion includes dotted line portions indicated by reference numerals E3, E4, E5, E6, E7, E8, and E9 in FIG. On the other hand, a short part is a shape which extends in an air flow direction and connects ends of a plurality of longitudinal parts. The short part includes dotted lines indicated by reference numerals E1 and E2 in FIG.

  The heating element 24 b of the heater 24 has facing portions H 1, H 2, H 3, H 4, H 5, H 6, H 7, H 8, and H 9 that extend while facing the electrode line 25 along the direction in which the electrode line 25 extends. Each of the facing portions H1 to H9 is opposed to a dotted line portion indicated by reference numerals H1, H2, H3, H4, H5, H6, H7, H8, and H9 of the electrode line 25. That is, the dotted line portions indicated by reference numerals H1 to H9 in the heater 24 and the dotted line portions indicated by reference numerals E1 to E9 in the electrode wire 25 are arranged so as to overlap each other in a front view as shown in FIG. .

  In FIG. 8, a pair of electrode plates 21 of the plurality of pairs of electrode plates 21 is shown as a representative, and the above-described application electrode plate and ground electrode plate are shown. As shown in FIG. 8, the two electrode lines 25 included in the ground electrode plate are connected to the ground. The two electrode lines 25 included in the application electrode plate are connected to the high voltage power supply circuit 84.

  The high voltage power supply circuit 84 includes a booster circuit that boosts the voltage (for example, 12V) of the battery B mounted on the vehicle, a DC-AC conversion circuit that converts the boosted DC voltage into AC, and the like. The high voltage power supply circuit 84 applies the boosted alternating voltage to the electrode line 25 of the application electrode plate. When an AC voltage is applied to the application electrode plate in this way, as described above with reference to FIG. 3, a discharge is performed between the electrode wire 25 included in the application electrode plate and the electrode wire 25 included in the ground electrode plate. The

  The DC voltage of the battery B is applied to the heating element 24b of the heater 24 included in each of the ground electrode plate and the application electrode plate. Specifically, as shown in FIG. 8, one end of the heat generating element 24 b is connected to the battery B via the controller 82, and the other end is connected to the ground via the switch 83. The controller 82 controls the amount of power supplied to the heating element 24b by duty-controlling the voltage applied to the heating element 24b.

  The terminal 24t shown in FIG. 5 is connected to one end of the heat generating element 24b, and is applied with a DC battery voltage. The terminal 24u shown in FIG. 5 is connected to the other end of the heating element 24b and connected to the ground. The terminal 25t shown in FIG. 5 is connected to the electrode wire 25 and is supplied with an AC voltage supplied to the application electrode plate. The high voltage power supply circuit 84 provides a discharging power supply circuit that applies an AC voltage to the electrode wire 25. The controller 82 provides a heater power supply circuit that applies a DC voltage to the heating element 24b.

  The operations of the high voltage power supply circuit 84, the controller 82 and the switch 83 are controlled by the microcomputer 81 of the ECU 80. The microcomputer 81 controls the operation of the controller 82 so that the power supply to the heating element 24b is stopped when the high voltage power supply circuit 84 supplies power to the electrode line 25. Further, the switch 83 is turned off so that the heater power supply circuit is opened from the ground. The microcomputer 81 controls the operation of the high voltage power supply circuit 84 so that the power supply to the electrode wire 25 is stopped when the controller 82 supplies power to the heating element 24b.

  The microcomputer 81 provided in the ECU 80 includes a storage device that stores a program and a central processing unit that executes arithmetic processing according to the stored program. The ECU 80 controls the operation of the internal combustion engine 10 based on detection values of various sensors. Specific examples of the various sensors include an accelerator pedal sensor 91, an engine rotation speed sensor 92, a throttle opening sensor 93, an intake pressure sensor 94, an intake air amount sensor 95, an exhaust temperature sensor 96, a NOx sensor 97, and the like.

  The accelerator pedal sensor 91 detects a user's accelerator pedal depression amount. The engine rotation speed sensor 92 detects the rotation speed (engine speed) of the output shaft 10 a of the internal combustion engine 10. The throttle opening sensor 93 detects the opening of the throttle valve 13. The intake pressure sensor 94 detects the pressure on the downstream side of the throttle valve 13 in the intake passage 10in. The intake air amount sensor 95 detects the mass flow rate of intake air. The exhaust temperature sensor 96 is attached between the DPF 14 and the NOx purification device 15 in the exhaust passage 10ex, and detects the temperature of the exhaust gas flowing into the NOx purification device 15. The NOx sensor 97 is attached to the downstream side of the NOx purification device 15 in the exhaust passage 10ex, and detects the amount of NOx that has flowed out without being reduced by the NOx purification device 15.

  In general, the ECU 80 controls the injection amount and injection timing of combustion fuel injected from a fuel injection valve (not shown) according to the rotation speed of the output shaft 10a and the load of the internal combustion engine 10. Further, the ECU 80 controls the operation of the reducing agent adding device A1 based on the exhaust temperature detected by the exhaust temperature sensor 96, the outflow NOx amount detected by the NOx sensor 97, and the like. Specifically, the control is performed by switching between discharge control for performing discharge by the discharge reactor 20 and heating control for heating the discharge reactor 20 while stopping the discharge.

  First, the contents of the discharge control will be described below.

  The discharge control is performed on condition that the internal combustion engine 10 is in operation. Then, the ozone addition control and the reformed fuel addition control described below are switched according to the temperature of the reduction catalyst (NOx catalyst temperature) of the NOx purification device 15. Specifically, if the NOx catalyst temperature is lower than the activation temperature T1 (for example, 250 ° C.) of the reduction catalyst, ozone addition control is performed, and if the NOx catalyst temperature is equal to or higher than the activation temperature T1, reformed fuel addition control is performed. To implement. Note that the NOx catalyst temperature is estimated from the exhaust temperature detected by the exhaust temperature sensor 96. Here, the activation temperature of the reduction catalyst indicates a temperature at which NOx can be reduced and purified by the reformed fuel.

In the ozone addition control, the operation of the high voltage power supply circuit 84 is controlled so that electric power corresponding to the required amount of ozone is supplied to the electrode plate 21, and the amount of air corresponding to the required amount of ozone is supplied to the discharge reactor 20. The operation of the air pump 20p is controlled so as to be supplied. The required ozone amount in the ozone addition control is set based on the NO ₂ inflow amount flowing into the NOx purification device 15 through the exhaust passage 10ex. According to the ozone generation control described above, ozone is generated in the discharge reactor 20, and the generated ozone is added to the exhaust passage 10ex through the reaction chamber 30a and the supply pipe 32.

  Further, in the ozone addition control, energization to the fuel heater 50 is stopped, and energization to the fuel injection valve 40 is stopped to stop fuel injection. Here, when energization of the fuel heater 50 is performed, ozone is heated and collapses. Moreover, if fuel injection is performed, ozone will react with fuel. In view of these points, in the above-described ozone generation control, heating by the fuel heater 50 is stopped and fuel injection is stopped. Therefore, since ozone reacts with the fuel and heat collapse can be avoided, the generated ozone is added to the exhaust passage 10ex as it is.

In the reformed fuel addition control, the operation of the fuel injection valve 40 is controlled so that the fuel injection amount corresponding to the required reformed fuel amount is obtained. Request reformed fuel amount in the reformed fuel addition control, NOx inflow amount flowing into the NOx purification device 15 through an exhaust passage 10Ex, the ratio of NO and NO ₂ contained in the NOx, is set based on the NOx catalyst temperature and the like .

  In the reformed fuel addition control, the operation of the fuel heater 50 is controlled so that the temperature of the reaction chamber 30a (reaction chamber temperature) falls within a predetermined temperature range. The predetermined temperature range is set to a temperature range in which a cool flame reaction occurs in the reaction chamber 30a but a hot flame reaction does not occur.

  In the reformed fuel addition control, the operation of the air pump 20p is controlled based on the amount of fuel injected from the fuel injection valve 40 so that the equivalence ratio falls within a predetermined equivalence ratio range. The predetermined equivalence ratio range is set to a temperature range in which a cool flame reaction occurs in the reaction chamber 30a but a hot flame reaction does not occur.

  In the reformed fuel addition control, the operation of the high voltage power supply circuit 84 is controlled so that electric power corresponding to the amount of air blown by the air pump 20p is supplied to the electrode plate 21. Then, the operation of the controller 82 is controlled to stop energization of the heater 24, and the switch 83 is turned off.

  Next, the contents of the above-described heating control will be described below.

  During the period when the operation of the air pump 20p is stopped, the exhaust in the exhaust passage 10ex may flow backward through the supply pipe 32 and flow into the discharge reactor 20. Further, the fuel vaporized in the reaction chamber 30a may flow into the discharge reactor 20. Then, foreign matter such as exhaust gas or fuel flows into the interelectrode passage 21a and may adhere to the surface of the electrode plate 21 and accumulate. If foreign matter accumulates on the surface of the electrode plate 21 in this manner, the discharge is inhibited and a sufficient amount of ozone cannot be generated.

  Therefore, in the present embodiment, by performing heating control in which the electrode plate 21 is heated by the heater 24, the foreign matter adhered and deposited on the electrode plate 21 is burned and removed. FIG. 9 is a flowchart illustrating a heating control process performed by the microcomputer 81. In this flowchart, heating control is performed roughly every time the travel distance of the vehicle reaches a predetermined distance.

  First, in step S10 of FIG. 9, the cumulative travel distance of the vehicle is calculated. In subsequent step S11, it is determined whether or not the calculated integrated travel distance is equal to or greater than the heating determination distance. If it is determined that the accumulated travel distance ≧ the heating determination distance, the heating control is performed in the subsequent step S12. In this heating control, power is supplied to the heating element 24b by the controller 82, power supply to the electrode line 25 by the high voltage power supply circuit 84 is stopped, and the switch 83 is turned off.

  The power supply to the heating element 24b by the controller 82 is performed by duty-controlling the battery voltage as described above. The duty value is a preset duty value, and power feeding is continued for a preset time. These duty values and durations are set to values sufficient for the foreign matter accumulated on the electrode plate 21 to burn. Further, at the time of heating control, the air pump 20p is operated so that the amount of air that supplies the minimum amount of oxygen necessary for burning the foreign matter accumulated on the surface of the electrode plate 21 is reached. The operation of the fuel injection valve 40 and the fuel heater 50 is stopped.

  In the subsequent step S13, the accumulated travel distance is reset to zero. Therefore, the integrated travel distance calculated in the next step S10 is shorter than the heating determination distance, and a negative determination is made in step S11. Therefore, every time the travel distance of the vehicle reaches a predetermined distance, the heating control is performed. Specifically, as shown in FIG. 10, the heating control is performed at times t1, t2, and t3 when the accumulated travel distance reaches the heating determination distance.

  As described above, according to the present embodiment, the heater 24 is disposed between the two electrode wires 25 provided on the electrode plate 21. Therefore, the heater 24 is located outside the discharge area. Therefore, the effect of electric field concentration by adopting the linear electrode wire 25 and the effect of creeping discharge by covering the electrode wire 25 with the dielectric film 26 can be prevented from being inhibited by the heater 24. Therefore, it is possible to remove foreign matter accumulated on the electrode plate 21 without hindering improvement in gas reforming ability due to these effects.

  Here, contrary to the present embodiment, if power is supplied to the heater 24 when power is supplied to the electrode wire 25, the distance between the electrode wire 25 and the heating element 24b is short, and therefore, the power is applied to the electrode wire 25. There is a concern that a high voltage flows into the heating element 24b. In this embodiment in view of this point, since the power supply to the heater 24 is prohibited at the time of power supply to the electrode wire 25, the above-mentioned concern can be suppressed.

  Further, the present embodiment includes a discharge power supply circuit that applies an AC voltage to the electrode wire 25 and a heater power supply circuit that applies a DC voltage to the heater 24. When supplying power to the electrode wire 25 by the discharge power supply circuit, the heater power supply circuit is opened from the ground. Specifically, the switch 83 is turned off to open. Therefore, the above-mentioned concern that a high voltage flows into the heat generating element 24b can be reliably avoided.

  Furthermore, in this embodiment, the electrode wire 25 extends linearly along the first virtual plane, and the heating element 24b of the heater 24 linearly extends along the second virtual plane parallel to the first virtual plane. Extend. The heating element 24b has opposing portions H1 to H9 extending along the direction in which the electrode line 25 extends and extending while facing the electrode line 25.

  Here, foreign substances are likely to adhere to and deposit on the portion of the gas passage surface formed by the electrode plate 21, that is, the surface 26 a of the dielectric film 26, facing the electrode line 25. In the present embodiment in view of this point, since the above-described facing portions H1 to H9 exist, the facing portions H1 to H9 mainly heat the portions that are easily deposited on the gas passage surface. Therefore, the deposit can be efficiently heated and removed.

  Further, in the present embodiment, three or more electrode plates 21 are arranged in a predetermined direction. For example, when the electrode plate shown in the middle of FIG. 3 is called the first electrode plate, the electrode plate shown in the upper row is called the second electrode plate, and the electrode plate shown in the lower row is called the third electrode plate, the dielectric that the first electrode plate has The body film 26 is provided on both surfaces of the first electrode plate. Two electrode lines 25 of the first electrode plate are provided between the dielectric films 26 disposed on both surfaces of the first electrode plate. Of these two electrode lines 25, the electrode line 25 located on the second electrode plate side forms a discharge region with the electrode line 25 included in the second electrode plate, and is located on the third electrode plate side. The electrode line 25 forms a discharge region between the electrode line 25 of the third electrode plate. According to this, since the first electrode plate discharges with each of the second electrode plate and the third electrode plate, the discharge reactor 20 can be downsized.

  Further, in the present embodiment, the heater 24 for heating the first electrode plate is disposed between two electrode lines 25 provided on the first electrode plate. As described above, since the heater 24 is included between the two electrode wires 25 provided on the first electrode plate, the heater 24 is disposed outside the discharge region in the above-described configuration in which the discharge reactor 20 is miniaturized. Is feasible.

(Second Embodiment)
In the first embodiment, the heating control is performed every time the travel distance of the vehicle reaches a predetermined distance. On the other hand, in this embodiment, as shown in FIG. 11, when the NOx purification rate is lowered to a predetermined value or less, the heating control is performed. That is, first, in step S20 of FIG. 11, an estimated NOx purification rate that is an estimated value of the NOx purification rate is calculated.

  Specifically, first, the NOx amount (NOx emission amount) contained in the exhaust gas of the internal combustion engine 10 is estimated based on the operation state of the internal combustion engine 10 such as the load of the internal combustion engine 10 and the engine speed NE. This NOx emission amount corresponds to the NOx inflow amount flowing into the NOx purification device 15. Next, the NOx outflow amount flowing out from the NOx purification device 15 is detected by the NOx sensor 97. A value obtained by subtracting the NOx outflow amount from the NOx inflow amount is the NOx purification amount. A value obtained by dividing the NOx purification amount by the NOx inflow amount is the NOx purification rate by the NOx purification device 15. Thus, the estimated NOx purification rate is calculated based on the estimated value of the NOx emission amount and the detected value of the NOx sensor 97.

  In the subsequent step S21, it is determined whether or not a condition for stably obtaining the NOx purification rate is satisfied based on the operating state of the internal combustion engine 10 and the NOx catalyst temperature. For example, in the transient period in which the operating state of the internal combustion engine 10 and the NOx catalyst temperature change rapidly in a short time, it is determined that the above condition is not satisfied. If it is determined that the condition is not satisfied, the process returns to step S20. If it is determined that the condition is satisfied, the process proceeds to step S22.

  In step S22, a determination value used in the determination process of the next step S23 is calculated based on the operating state of the internal combustion engine 10 and the NOx catalyst temperature. In subsequent step S23, in step S23, it is determined whether or not the estimated NOx purification rate calculated in step S20 is equal to or less than the determination value calculated in step S22. If it is determined that the estimated NOx purification rate ≦ the determination value, heating control is performed in the subsequent step S24.

  As described above, according to the present embodiment, the estimated NOx purification rate is calculated, and the heating control is performed based on the calculation result. Therefore, it is possible to remove the foreign matter accumulated on the electrode plate 21 in a timely manner. That is, it is possible to suppress the heating control until the purification rate is sufficiently high. In addition, when the purification rate is equal to or less than the determination value, the heating control is performed to remove the foreign matter accumulated on the electrode plate 21, and the purification rate can be recovered.

(Third embodiment)
In the embodiment shown in FIG. 5, the heater 24 is arranged on the second imaginary plane so that the longitudinal portion of the heating element 24 b and the longitudinal portion of the electrode line 25 are in a positional relationship. On the other hand, in the electrode plate 21B of the present embodiment shown in FIG. 12, the heater 24 is arranged on the second virtual plane so that the longitudinal portion of the heating element 24b and the longitudinal portion of the electrode line 25 are in a parallel positional relationship. Has been.

  The heating element 24b of the heater 24 has a facing portion that extends while facing the electrode line 25 along the direction in which the electrode line 25 extends. This facing portion is a dotted line portion indicated by reference numerals H10, H11, H12, H13, H14, H15, H16, H17, H18, H19, H20, H21, H22, H23, and H24 in FIG. Each of the facing portions H10 to H24 is a dotted line portion indicated by reference numerals E10, E11, E12, E13, E14, E15, E16, E17, E18, E19, E20, E21, E22, E23, E24 among the electrode lines 25 (see FIG. 14). That is, the dotted line portions indicated by reference signs H10 to H24 in the heater 24 and the dotted line portions indicated by reference signs E10 to E24 in the electrode wire 25 are arranged so as to overlap each other in a front view as shown in FIG. .

  Thus, by arranging the longitudinal portion of the heating element 24b and the longitudinal portion of the electrode line 25 to be parallel, the opposing portions H10 to H10 are compared with the case where the longitudinal portions are arranged to be vertical. The area of H24 can be increased. Therefore, an effect of intensively heating a portion that is easily deposited on the surface 26a (gas passage surface) of the dielectric film 26 is promoted.

(Fourth embodiment)
In the present embodiment, the heater 24 shown in FIG. 3 is eliminated by causing the discharge electrode wire 25 to function as a heater. That is, the electrode plate 21C according to the present embodiment has a plate-like base material 27 formed of a dielectric as shown in FIG. Electrode wires 25 are provided on both surfaces of the base material 27, and dielectric films 26 are provided on both surfaces of the base material 27 so as to cover the electrode wires 25.

  Then, one discharge terminal 25t to which an AC voltage is applied is connected to the electrode wire 25 of the embodiment shown in FIG. On the other hand, in the present embodiment, the discharge terminal 25t also serves as a heating terminal, and in addition to the discharge terminal 25t, a heating ground terminal 25u is also connected to the electrode wire 25.

  The gas reformer according to the present embodiment also includes a high voltage power supply circuit 84 and a controller 82 similar to those in FIG. The AC voltage by the high-voltage power supply circuit 84 and the DC voltage duty-controlled by the controller 82 are switched so that the voltage can be applied to the terminal 25t. On the other hand, the terminal 25u is connected to the ground via the switch 85. The high voltage power supply circuit 84 provides a discharge power supply circuit that applies an AC voltage to the electrode wire 25 so as to cause a discharge in the pair of electrode plates 21C. The controller 82 provides a heater power supply circuit that applies a DC voltage to the electrode wire 25 so that the electrode wire 25 functions as a heater.

  As shown in FIG. 16, during the discharge control, the high voltage power supply circuit 84 is connected to the terminal 25t and the switch 85 is turned off. Thus, the current flowing from the terminal 25t to the electrode line 25 is discharged toward the opposing electrode line 25 as shown by the dotted arrow in FIG. 15 without flowing into the ground through the switch 85.

  As shown in FIG. 17, at the time of heating control, the controller 82 is connected to the terminal 25t and the switch 85 is turned on. As a result, a direct current supplied from the battery B flows to the ground without being discharged toward the opposing electrode line 25. As a result, the electrode wire 25 generates heat, the electrode plate 21C is heated, and the foreign matter adhered and deposited on the electrode plate 21C is burned and removed.

  As described above, according to the present embodiment, since the discharge electrode wire 25 can also function as a heater, the following problem in the case where a heater is provided separately from the electrode wire 25 can be eliminated. That is, it is possible to solve the problem that “the effect of electric field concentration by employing the linear electrode wire 25 and the effect of creeping discharge by covering the electrode wire 25 with the dielectric film 26 are hindered by the heater”.

  Further, in the present embodiment, when the power supply to the electrode line 25 is performed by the discharge power supply circuit, the heater power supply circuit is set in an open state separated from the ground. Specifically, the switch 85 is turned off to open. Therefore, it is possible to avoid a high voltage from the discharging power supply circuit from flowing into the ground, and it is possible to switch between discharging by AC voltage and functioning as a heater by DC voltage.

(Fifth embodiment)
In the reducing agent addition apparatus A1 shown in FIG. 1, the discharge reactor 20 is disposed on the upstream side of the air flow in the reaction chamber 30a. On the other hand, in the reducing agent addition apparatus A2 according to the present embodiment, as shown in FIG. In this reducing agent addition apparatus A2, the oxidation reaction of the fuel occurring in the reaction chamber 30a is a very small part, and most of the oxidation reaction is configured to occur in the interelectrode passage 21a of the discharge reactor 20. In the interelectrode passage 21a, oxygen molecules in the air are ionized, and the fuel is oxidized in an environment in which ionized active oxygen atoms are present. As a result, in the discharge reactor 20, a part of the fuel is oxidized and a reformed fuel is generated.

  As described above, even in the reducing agent adding apparatus A2 that reforms the fuel in the discharge reactor 20, a configuration in which the heater 24 is disposed outside the discharge region (see FIG. 3), or the electrode wire 25 has a heater. A configuration that also serves as a reference (see FIG. 15) can be employed.

(Sixth embodiment)
In the embodiment shown in FIG. 1, air is supplied to the discharge reactor 20 by the air pump 20p. On the other hand, in the reducing agent addition apparatus according to the present embodiment, a part of the intake air of the internal combustion engine 10 is branched and flows into the discharge reactor 20.

  Specifically, in the intake passage 10in, the downstream portion of the compressor 11c and the upstream portion of the cooler 12 and the flow passage 22a of the discharge reactor 20 are connected by piping. As a result, the high-temperature intake air before being cooled by the cooler 12 can be supplied to the discharge reactor 20. Further, the downstream portion of the cooler 12 and the flow passage 22a in the intake passage 10in are connected by piping. As a result, the low-temperature intake air after being cooled by the cooler 12 can be supplied to the discharge reactor 20.

  Furthermore, in this embodiment, the switching valve (not shown) which switches the intake air supplied to the discharge reactor 20 to a high temperature intake and a low temperature intake is provided. By switching to supply low-temperature intake air during ozone generation, the generated ozone is prevented from being destroyed by the heat of the intake air. In addition, when ozone is not generated, the high temperature intake air is switched to supply, and the fuel heated by the heater 50 is prevented from being cooled by the intake air in the reaction chamber. Further, by controlling the opening degree of the switching valve, the amount of the intake air supercharged by the supercharger 11 is controlled to be supplied to the discharge reactor 20.

  As described above, the reducing agent addition apparatus according to the present embodiment includes the electromagnetic valve 36, and by opening the electromagnetic valve 36, a part of the intake air supercharged by the supercharger 11 is supplied to the discharge reactor 20. Therefore, oxygen-containing air can be supplied to the discharge reactor 20 without using the air pump 20p shown in FIG.

  As described above, even in the case of a reducing agent addition apparatus that introduces a portion of the intake air into the discharge reactor 20, a configuration in which the heater 24 is disposed outside the discharge region (see FIG. 3), or the electrode wire 25 is a heater. (See FIG. 15).

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made as illustrated below. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

  High voltage power supply circuit 84 (discharge power supply circuit) shown in FIGS. 8 and 16 applies an alternating voltage to electrode wire 25. On the other hand, the discharging power supply circuit may be a circuit in which a direct current voltage is pulsed and applied to the electrode wire 25 intermittently.

  The heating control may be performed at the time of non-generation where neither generation of ozone nor generation of reformed fuel is required. As a specific example of the non-generation, the NOx catalyst temperature is lower than the activation temperature and the NOx adsorption amount is in a saturated state, or the NOx catalyst temperature exceeds the reducible range and becomes high. There are cases.

  In the discharge reactor 20 according to each embodiment described above, three or more electrode plates 21 are arranged side by side in a predetermined direction. On the other hand, the gas reformer according to the present invention may be applied to a discharge reactor provided with two electrode plates 21, that is, a pair of electrode plates 21.

  When the pair of electrode plates 21 is configured as one set in this way, it is not necessary to provide the two electrode lines 25 on the one electrode plate 21A, 21B, 21C, and it is only necessary to provide one electrode line 25. . Specifically, as shown in FIG. 3, the electrode wires 25 may be provided on one side of the heater 24 instead of providing the electrode wires 25 on both sides of the heater 24.

  Alternatively, as shown in FIG. 15, the electrode wire 25 serving as a heater may be provided on both surfaces of the substrate 27, and the electrode wire 25 serving as a heater may be provided on one surface of the substrate 27. Or in the structure which provided the electrode wire 25 in the single side | surface of the base material 27, the structure which provided the heater in the surface on the opposite side to the surface in which the electrode wire 25 was provided among the base materials 27, and made the electrode wire 25 only for discharge. It may be.

  In the embodiment shown in FIG. 1, a reduction catalyst that physically captures (that is, adsorbs) NOx is employed. However, in a combustion system that employs a reduction catalyst that traps (that is, occludes) NOx by chemical bonding, A reducing agent addition apparatus may be applied.

  When the internal combustion engine 10 is burning in a state leaner than the stoichiometric air-fuel ratio, the reducing agent addition device is applied to a combustion system in which the NOx purification device 15 adsorbs NOx and reduces NOx in other than lean combustion. Also good. In this case, ozone may be generated during lean combustion, and reformed fuel may be generated at times other than lean combustion. As a specific example of the catalyst that captures NOx during lean combustion in this way, an occlusion reduction catalyst using platinum and barium supported on a carrier can be cited.

  The reducing agent addition device may be applied to a combustion system in which the NOx purification device 15 having no adsorption or storage function is employed. In this case, the NOx purification device 15 may be an iron-based or copper-based catalyst having NOx reduction performance in a predetermined temperature range during lean combustion, and the reformed fuel may be supplied as a reducing agent to these catalysts. It ’s fine.

  In each of the above-described embodiments, the gas reforming apparatus according to the present invention is applied to a reducing agent addition apparatus that uses fuel as a reducing agent. On the other hand, the gas reforming apparatus according to the present invention may be applied to a reducing agent addition apparatus that uses urea as a reducing agent by adding urea water upstream of the NOx purification device 15. For example, the use which adds the ozone produced | generated by the gas reformer to the upstream of the NOx purification apparatus 15 with urea water is mentioned as a specific example.

  In each embodiment mentioned above, the reducing agent addition apparatus is applied to the combustion system mounted in the vehicle. On the other hand, a reducing agent addition device may be applied to a stationary combustion system. In the embodiment shown in FIG. 1, a reducing agent addition device is applied to a compression self-ignition diesel engine, and light oil used as a fuel for combustion is used as a reducing agent. On the other hand, gasoline used as a fuel for combustion may be used as a reducing agent by applying a reducing agent addition device to an ignition ignition type gasoline engine.

  In each of the above-described embodiments, the gas reformer according to the present invention is applied to exhaust gas purification of the internal combustion engine 10. On the other hand, the gas reforming apparatus according to the present invention may be applied to an air conditioning apparatus that includes ozone generated by the gas reforming apparatus in the conditioned air and blows the conditioned air into the room. Alternatively, the gas reforming apparatus according to the present invention may be applied to an apparatus that generates ozone water by blowing out ozone generated by the gas reforming apparatus.

  DESCRIPTION OF SYMBOLS 20 ... Discharge reactor (gas reformer) 21, 21B, 21C ... Electrode plate, 24 ... Heater, 25 ... Electrode wire, 26 ... Dielectric film, 82 ... Controller (heater feeding circuit), 84 ... High voltage power supply Circuit (feeding circuit for discharge), A1, A2,... Reducing agent addition device.

Claims (5)

An electrode plate having a linearly extending electrode wire (25) and a dielectric film (26) covering the electrode wire, wherein at least a pair of electrode plates (21, 21) for reforming gas by discharge from the electrode wire 21B)
A heater (24) for generating heat by feeding and heating the electrode plate;
With
The heater is disposed outside the discharge region between the electrode wire of one of the pair of electrode plates and the electrode wire of the other electrode plate ,
Three or more electrode plates are arranged in a predetermined direction,
A predetermined electrode plate among the three or more electrode plates is referred to as a first electrode plate, an electrode plate disposed on one side of the first electrode plate is referred to as a second electrode plate, and the first electrode plate is referred to as a second electrode plate. The electrode plate arranged opposite to the other side with respect to one electrode plate is called a third electrode plate,
The dielectric film of the first electrode plate is provided on both surfaces of the first electrode plate,
Two electrode lines of the first electrode plate are provided between the dielectric films disposed on both surfaces of the first electrode plate,
Of the two electrode lines of the first electrode plate, the electrode line located on the second electrode plate side forms the discharge region with the electrode line of the second electrode plate,
Of the two electrode lines of the first electrode plate, the electrode line located on the third electrode plate side forms the discharge region with the electrode line of the third electrode plate,
The gas reforming apparatus , wherein the heater for heating the first electrode plate is disposed between two electrode wires provided on the first electrode plate .   The gas reforming apparatus according to claim 1, wherein power supply to the heater is prohibited during power supply to the electrode wire. A discharge power supply circuit (84) for applying an alternating or pulsed voltage to the electrode wire;
A heater power supply circuit (82) for applying a DC voltage to the heater;
With
3. The gas reforming apparatus according to claim 2, wherein when the power supply to the electrode wire is supplied by the discharge power supply circuit, the heater power supply circuit is in an open state separated from the ground. The electrode line extends linearly along the first virtual plane,
The heater extends linearly along a second virtual plane parallel to the first virtual plane,
The said heater has the opposing part (H1-H9, H10-H24) extended along the direction where the said electrode wire is extended while facing the said electrode wire, The any one of Claims 1-3 characterized by the above-mentioned. The gas reformer described in 1. A NOx purification device (15) for purifying NOx contained in the exhaust gas of the internal combustion engine (10) on the reduction catalyst is provided in a combustion system provided in the exhaust passage (10ex), and upstream of the reduction catalyst in the exhaust passage. In the reducing agent addition device for adding the reducing agent to the side,
The gas reformer (20) according to any one of claims 1 to 4 , wherein oxygen contained in the air is reformed into ozone by discharge.
A reaction vessel (30) that partially oxidizes the fuel by mixing the air containing ozone reformed by the gas reformer and the fuel that is a hydrocarbon compound;
With
A reducing agent addition apparatus characterized in that fuel partially oxidized inside the reaction vessel is used as the reducing agent.

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