JP2013050071A - Exhaust emission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma reactor capable of generating plasma having uniform intensity from an upstream side to a downstream side.SOLUTION: The plasma reactor 1 is provided with: a plurality of cylindrical outer peripheral electrodes 31 provided along an exhaust flow direction in an exhaust pipe 2 through which the exhaust of an engine flows; and a plurality of linear or rod-like inner electrodes 32 provided coaxially to the center of the plurality of the outer peripheral electrodes. The plasma reactor 1 is provided with: a first feed plug 41 provided in the exhaust pipe 2 on the upstream side from the plurality of the outer peripheral electrodes 31; and a second feed plug 42 provided in the exhaust pipe 2 on the downstream side from the plurality of the outer peripheral electrodes 31. Ends on the upstream side of the plurality of the inner electrodes 32 are held by the first feed plug 41 through a first conductive connection member 51, ends on the downstream side of the plurality of the inner electrodes 32 are held by the second feed plug 42 through a second conductive connection member 52, and the first feed plug 41 and the second feed plug 42 are connected to the same electric potential pole of a high voltage power source 6.

Description

  The present invention relates to an exhaust emission control device. More specifically, the present invention relates to an exhaust gas purification device that purifies exhaust gas by plasma generated by applying a voltage to an electrode pair of a cylindrical outer electrode and an inner electrode provided coaxially at the center of the outer electrode.

  A so-called plasma reactor has been proposed as one of the exhaust gas purification devices for purifying exhaust gas from an internal combustion engine. This plasma reactor purifies harmful components in the exhaust by applying a high voltage between the electrodes provided in the exhaust pipe to generate plasma.

  Patent Documents 1 and 2 show specific configurations of plasma reactors. This plasma reactor is configured by arranging a plurality of electrode pairs, each composed of a cylindrical outer electrode and a linear inner electrode coaxially provided at the center of the outer electrode, in the exhaust pipe. Further, each outer peripheral electrode is grounded, and each inner electrode is connected to a power supply plug connected to a high voltage power source after one end side thereof is gathered into one in the exhaust pipe by a lattice member or a net-like conductive wire.

Japanese Patent Laying-Open No. 2005-307832 Japanese Patent No. 3206628

  As described above, in the conventional plasma reactor, by providing the inner electrode coaxially in the cylindrical outer peripheral electrode, the distance from the inner electrode to the inner peripheral surface of the outer peripheral electrode can be made equal, so that it is perpendicular to the flow direction of the exhaust gas. Uniform plasma can be generated without deviation in cross-sectional view. However, in the conventional plasma reactor, only one end side of the upstream side or the downstream side among the internal electrodes extending inside the outer peripheral electrode is connected to the power supply plug. In some cases, the intensity of plasma generated between the upstream side and the downstream side becomes inhomogeneous, and there is a time difference in plasma generation between the upstream side and the downstream side.

  The present invention is an exhaust purification device that generates plasma between a cylindrical outer peripheral electrode and an internal electrode provided at the center thereof, and can generate plasma of uniform intensity from the upstream side to the downstream side. An object is to provide an exhaust emission control device.

  In order to achieve the above object, the present invention provides a plurality of cylindrical outer peripheral electrodes (e.g., an exhaust pipe (e.g., an exhaust pipe 2 described later)) through which an exhaust gas from an internal combustion engine flows. And a plurality of linear or rod-like internal electrodes (for example, an internal electrode 32 described later) provided coaxially at the centers of the plurality of outer peripheral electrodes, and a voltage is applied between the electrodes. Provided is an exhaust gas purification device (for example, a plasma reactor 1 described later) for purifying exhaust gas by plasma generated by application. The exhaust purification device includes: a first power supply plug (for example, a first power supply plug 41 described later) provided upstream of the plurality of outer peripheral electrodes in the exhaust pipe; and the plurality of outer peripheral electrodes in the exhaust pipe. A second power supply plug (for example, a second power supply plug 42 to be described later) provided on the further downstream side, and an upstream end portion of the plurality of internal electrodes has a conductive first connection member (for example, to be described later). The first power supply plug is held via the first connection member 51), and the downstream end portions of the plurality of internal electrodes are electrically conductive second connection members (for example, a second connection member 52 described later). The first power supply plug and the second power supply plug are connected to the same potential pole of a high-voltage power supply (for example, a high-voltage power supply 6 described later).

In the present invention, an internal electrode is coaxially provided at the center of the outer peripheral electrode extending along the exhaust flow direction, and the upstream end of the internal electrode is held by the first power supply plug via the conductive first connecting member. Then, the downstream end is held by the second power supply plug via the conductive second connection member, and the first power supply plug and the second power supply plug are connected to the same potential electrode of the high-voltage power supply. As a result, the difference in impedance can be reduced, so that the plasma intensity can be made uniform from the upstream side to the downstream side, and the time difference of plasma generation can be reduced.
Also, by holding both ends of the internal electrode with the first and second power supply plugs provided in the exhaust pipe, the position of the internal electrode is set so that the distance between the internal electrode and the external electrode does not change. Can be kept in the center of. Therefore, it is possible to stably generate plasma having a uniform intensity from the upstream side to the downstream side.

  In this case, the first and second power supply plugs include a socket (for example, a socket 416 described later) that conducts to a center electrode (for example, a center electrode 411, 421 described later), and the first and second connection members are A connecting portion (for example, a connecting portion 511 described later) that connects the ends of the adjacent internal electrodes, and a support shaft (for example, described later) that extends along a plane perpendicular to the flow direction of the exhaust gas from the connecting portion. It is preferable that the socket has a positioning mechanism (for example, a coil spring 4164 described later) for restricting movement of the support shaft along the extending direction thereof.

  In the present invention, the first and second power supply plugs are provided with sockets that are connected to the center electrode, and the support shafts extending along the plane perpendicular to the flow direction of the exhaust gas are connected to the sockets. The connection member is connected to the first and second power supply plugs. Conventionally, in order to fix the position and posture of the connecting member that connects the internal electrode and the power supply plug in the exhaust pipe, it was necessary to fix the connecting member to the end of the outer peripheral electrode via an insulating material. Accordingly, the first and second connecting members, to which both ends of each internal electrode are connected, are directly held in the exhaust pipe by the first and second power supply plugs, thereby eliminating the need for such components. Further, the first and second connection members are connected by connecting the support shafts of the first and second connection members to sockets of the first and second power supply plugs having a positioning mechanism for restricting movement along the extending direction. Since the displacement of the member in the exhaust pipe can be prevented and the internal electrode can be kept at the center of the outer peripheral electrode, the homogeneous plasma can be stably generated as described above.

  In this case, it is preferable that the socket has a rotation restricting mechanism (for example, a second accommodating portion 4162 of the socket 416 described later) that restricts rotation around the support shaft.

  In the present invention, by connecting the support shaft to a socket having a rotation restricting mechanism for restricting the rotation of the first and second connection members around the support shaft, rotation of the connection member in the exhaust pipe is prevented, and the internal electrode Thus, the homogeneous plasma can be stably generated as described above.

  In this case, it is preferable that an outer peripheral surface on the inner side of the exhaust pipe (for example, an outer peripheral surface 415 on the front end side of an insulator 412 described later) of the first and second power supply plugs is formed in an uneven shape. .

  In the present invention, by forming the outer peripheral surface on the inner side of the exhaust pipe out of the power plug, it can be prevented from discharging to the exhaust pipe and the outer peripheral electrode along the surface of the power plug in the exhaust pipe. As described above, it is possible to stably generate a homogeneous plasma.

It is a perspective view which shows schematic structure of the plasma reactor which concerns on one Embodiment of this invention. It is a front view of the plasma reactor which concerns on the said embodiment. It is sectional drawing of the plasma reactor which concerns on the said embodiment. It is a fragmentary sectional view which shows the connection structure of the 2nd connection member and internal electrode which concern on the said embodiment. It is a perspective view which shows the structure of the front-end | tip part of the support shaft of the 1st connection member which concerns on the said embodiment. It is sectional drawing which shows the structure of the front-end | tip part of the 1st electric power feeding plug which concerns on the said embodiment. It is a figure which shows the procedure which mounts | wears the socket with the support shaft which concerns on the said embodiment. It is a figure which shows the procedure which mounts | wears the socket with the support shaft which concerns on the said embodiment. FIG. 9 is a cross-sectional view taken along line VIII-VIII in FIG. 8. It is a figure which shows an example of the exhaust gas purification system to which the plasma reactor which concerns on the said embodiment is applied. It is a figure which shows an example of the exhaust gas purification system to which the plasma reactor which concerns on the said embodiment is applied. It is a figure which shows the modification of a connection member. It is a figure which shows the example which provided the honeycomb structure inside the plasma discharge unit.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a schematic configuration of a plasma reactor 1 according to the present embodiment. FIG. 2 is a front view of the plasma reactor 1. FIG. 3 is a cross-sectional view of the plasma reactor 1. As will be described later with reference to FIGS. 10 and 11, the plasma reactor 1 is mounted on a vehicle as one of exhaust purification devices that purifies exhaust gas from an internal combustion engine (hereinafter referred to as “engine”).

  The plasma reactor 1 includes a cylindrical exhaust pipe 2 constituting a part of an exhaust passage of an engine (not shown), a plurality of cylindrical plasma discharge units 3 accommodated in the exhaust pipe 2, and the plurality of plasma discharges. A high voltage power source 6 for generating plasma by the unit 3, a first power supply plug 41 and a second power supply plug 42 for supplying power from the high voltage power supply 6 to the plurality of plasma discharge units 3 inside the exhaust pipe 2, and the exhaust pipe 2 The power supply plugs 41 and 42 are internally configured to include a first connection member 51 and a second connection member 52 that electrically connect the plurality of plasma discharge units 3. The plasma reactor 1 is disposed in a part of an exhaust pipe of a vehicle (not shown) so that engine exhaust flows from the front side to the back side in FIGS. 1 and 2 and from left to right in FIG. Incorporated.

  Each plasma discharge unit 3 includes a cylindrical outer peripheral electrode 31 provided along the extending direction of the exhaust pipe 2, that is, the exhaust flow direction, and a linear or bar-like shape provided coaxially at the center of the outer peripheral electrode 31. An electrode pair with the internal electrode 32 is used. As shown in FIGS. 1 to 3, the plurality of plasma discharge units 3 constituted by the electrode pairs of the outer peripheral electrode 31 and the inner electrode 32 are bundled in parallel with their both ends aligned, and then the exhaust pipe 2. Housed inside. More specifically, in the present embodiment, two plasma discharge units 3 are provided in the upper stage, three in the middle stage, and two in the lower stage in the exhaust pipe 2. However, in the present invention, the number of the plasma discharge units 3 and the arrangement form in the exhaust pipe 2 are not limited thereto. In the present embodiment, the cylindrical outer peripheral electrode 31 having a circular cross-sectional view perpendicular to the flow direction of the exhaust gas will be described as an example. However, the present invention is not limited to this. For example, a cylindrical outer peripheral electrode that is polygonal in cross-sectional view may be used.

  The first power supply plug 41 includes a rod-shaped center electrode 411 extending along the vertical direction, an insulator 412 that holds the center electrode 411, and a housing 413 that holds the insulator 412. The outer peripheral surface 414 on the base end side and the outer peripheral surface 415 on the distal end side of the insulator 412 are each formed in an uneven shape to prevent creeping discharge. Since the second power supply plug 42 has the same configuration as the first power supply plug 41 described above, detailed description thereof is omitted.

  A first plug mounting portion 21 having a first plug hole (not shown) is provided on the upstream side of the plasma discharge unit 3 in the exhaust pipe 2, and a second (not shown) downstream of the plasma discharge unit 3 is provided. A second plug attachment portion 22 in which a plug hole is formed is provided. The power supply plugs 41, 42 are screwed into the plug holes of the plug mounting portions 21, 22 by screws (not shown) formed in the housings 413, 423, so that the respective tip portions are plasma in the exhaust pipe 2. It is attached to the exhaust pipe 2 along the vertical direction so as to face the upstream side and the downstream side of the discharge unit 3.

  As shown in FIG. 3, the first connection member 51 is provided in the exhaust pipe 2 on the upstream side of the plasma discharge unit 3, and the upstream end of the internal electrode 32 of each plasma discharge unit 3 and the first power supply. The plug 41 is electrically connected. The second connection member 52 is provided in the exhaust pipe 2 on the downstream side of the plasma discharge unit 3, and electrically connects the end portion on the downstream side of the internal electrode 32 of each plasma discharge unit 3 and the second power supply plug 42. Connect. That is, both ends of the internal electrode 32 of each plasma discharge unit 3 are held by the power supply plugs 41 and 42 via the connection members 51 and 52.

As shown in FIGS. 1 and 2, the first connecting member 51 includes a connecting portion 511 that connects the end portions of the internal electrodes 32 of the plasma discharge units 3 adjacent to each other, and the connecting portion 511 is perpendicular to the flow direction of the exhaust gas. And a support shaft 515 that extends in the vertical direction, more specifically along the vertical direction, and is fitted to the tip of the first power supply plug 41. The connecting portion 511 and the support shaft 515 are integrally formed of a conductive material. As shown in FIG. 2, the connecting portion 511 extends in the horizontal direction and connects the internal electrodes 32 of two adjacent plasma discharge units 3 provided in the upper stage in the exhaust pipe 2. A second connecting member 513 connecting the internal electrodes 32 of three adjacent plasma discharge units 3 provided in the middle stage in the exhaust pipe 2 extending along the horizontal direction, and a lower stage in the exhaust pipe 2 extending in the horizontal direction. And a third connecting member 514 that connects the internal electrodes 32 of two adjacent plasma discharge units 3.
Since the second connection member 52 has the same configuration as the first connection member 51 described above, detailed description thereof is omitted.

  As shown in FIG. 3, stoppers 33 and 34 for connecting to connection members 51 and 52 are provided at both ends of each internal electrode 32. The upstream end of each internal electrode 32 is inserted into an insertion hole (not shown) formed in the first connection member 51 and is fixed to the first connection member 51 by a stopper 33. On the other hand, as shown in FIG. 4, the downstream end portion of each internal electrode 32 is inserted into the insertion hole 521 formed in the second connection member 52, and between the stopper 34 and the second connection member 52. It is elastically supported with a conductive spring 35 interposed. Thereby, since the elastic force that pushes the stopper 34 to the outside of the second connection member 52 always acts on the internal electrode 32, the internal electrode 32 bends between the first connection member 51 and the second connection member 52, As a result, it is possible to prevent the distance between the internal electrode 32 and the outer peripheral electrode 31 from changing. In addition, by supporting the internal electrode 32 between the first connection member 51 and the second connection member 52 in such a manner that the internal electrode 32 can extend and contract, bending due to thermal expansion of the internal electrode 32 can also be prevented.

  As shown in FIG. 3, in order to prevent discharge between the surfaces of the connection members 51 and 52 and the end portions of the outer peripheral electrodes 31 of the respective plasma discharge units 3, the connection members 51 and 52 are provided at both end surfaces of the outer peripheral electrode 31. To the inner surface of the exhaust pipe 2 so that the distance along the flow direction of the exhaust is separated by “L”. If the interelectrode distance between the internal electrode 32 and the outer peripheral electrode 31 (the distance between the outer peripheral surface of the inner electrode 32 and the inner peripheral surface of the outer peripheral electrode 31) is “L ′”, the connecting members 51 and 52 The distance L between the outer peripheral electrode 31 is set longer than the interelectrode distance L ′. The connection members 51 and 52 are connected to the power supply plugs 41 and 42 through a connection structure which will be described later with reference to FIGS. 5 to 9, and their positions and postures in the exhaust pipe 2 are fixed. Therefore, according to the plasma reactor 1 of the present embodiment, an insulating material for maintaining the position and posture of the connection members 51 and 52 in the exhaust pipe 2 is provided between the connection members 51 and 52 and the outer peripheral electrode 31. There is no need to intervene.

  The center electrode 421 of the first power supply plug 41 and the center electrode 421 of the second power supply plug 42 as described above are connected in parallel to the high-voltage power supply 6, that is, to the same potential electrode of the high-voltage power supply 6. The outer peripheral electrode 31 is grounded. Thereby, a voltage can be applied between the internal electrode 32 and the outer peripheral electrode 31 of each plasma discharge unit 3, and a plasma can be generated.

  Next, a connection structure between the connection member and the power supply plug will be described with reference to FIGS. In the following description, a connection structure between the first connection member 51 and the first power supply plug 41 will be described with reference to FIGS. Since the connection structure between the second connection member 52 and the second power supply plug 42 is the same as the connection structure between the first connection member 51 and the first power supply plug 41, detailed description thereof is omitted.

FIG. 5 is a perspective view showing the configuration of the support shaft 515 of the first connecting member.
The support shaft 515 includes a main body 516 that is rectangular in cross-sectional view and a tip portion 517 that is formed in a columnar shape in cross-sectional view. An annular recess 518 that engages a coil spring described later is formed at the tip 517. A tapered surface 519 is formed on the distal end side of the distal end portion 517.

FIG. 6 is a cross-sectional view showing the configuration of the tip of the first power supply plug 41.
A concave socket 416 that is electrically connected to the center electrode 411 and into which the support shaft 515 is fitted is formed at the tip of the first power supply plug 41. The outer periphery of the socket 416 is covered with an insulator 412.

  The socket 416 is formed in a columnar shape in a cross-sectional view and houses a first housing portion 4161 that houses a tip portion 517 of the support shaft 515, and a second housing portion that is formed in a rectangular shape in a cross-sectional view and houses the main body 516 of the support shaft 515. 4162. An annular recess 4163 is formed in the first housing portion 4161, and a coil spring 4164 as a conductive elastic member is provided in the recess 4163.

7 and 8 are diagrams showing a procedure for attaching the support shaft 515 to the socket 416. FIG.
First, as shown in FIG. 7, the support shaft 515 is inserted into the socket 416 from the distal end portion 517, and the support shaft 515 is pushed into the back of the socket 416 while the coil spring 4164 is elastically deformed by the tapered surface 519. As shown in FIG. 8, when the concave portion 518 of the support shaft 515 reaches the position of the coil spring 4164, the shape of the coil spring 4164 is formed in the annular space formed by the concave portion 518 of the support shaft 515 and the concave portion 4163 of the socket 416. As a result, the coil spring 4164 is locked to the recess 518 of the support shaft 515. As a result, the support shaft 515 is elastically supported by the coil spring 4164 in a state of being electrically connected to the center electrode 421 in the socket 416.

  As described above, in a state where the support shaft 515 is mounted on the socket 416, the movement of the support shaft 515 along the extending direction, that is, the vertical direction is restricted by the coil spring 4164. Therefore, in this embodiment, the coil spring 4164 provided in the socket 416 constitutes a positioning mechanism that restricts the movement of the support shaft 515 along the vertical direction.

FIG. 9 is a cross-sectional view taken along line VIII-VIII in FIG. 8, and is a cross-sectional view of the support shaft 515 and the socket 416 in a state where the support shaft 515 is connected to the socket 416. In FIG. 9, the exhaust gas flows from the left side to the right side.
As shown in FIG. 9, the main body 516 of the support shaft 515 is formed in a rectangular shape in cross-sectional view, and the internal cross-sectional shape of the second housing portion 4162 of the socket 416 is formed in a rectangular shape as with the main body 516. . Thus, by making the cross-sectional shape inside the socket 416 the same rectangular shape as the support shaft 515, the rotation of the first connecting member 51 around the support shaft 515 is restricted. Therefore, in the present embodiment, a rotation restricting mechanism that restricts rotation around the support shaft 515 is configured by the second housing portion 4162 of the socket 416 formed in the same cross-sectional shape as the support shaft 515. The cross-sectional shapes of the support shaft 515 and the socket 416 are not limited to the rectangular shape as in the present embodiment, but may be any shape that can regulate the rotation around the support shaft 515, such as an elliptical shape or a polygonal shape. It may be a shape.

  Next, an example of an exhaust purification system to which the plasma reactor 1 as described above is applied will be described with reference to FIGS. 10 and 11.

FIG. 10 shows that the plasma reactor 1 is applied to an exhaust purification system 7A equipped with a selective reduction catalyst (HC-SCR (Selective Catalytic Reduction Catalyst)) 73 that reduces and removes NOx in exhaust using hydrocarbons in exhaust as a reducing agent. It is a figure which shows an example. In this system 7A, as shown in FIG. 10, it is preferable to provide the exhaust gas passage 72 in the order of the plasma reactor 1, the selective reduction catalyst 73, and the oxidation catalyst 74 from the upstream side to the downstream side.
In the exhaust purification system 7A as shown in FIG. 10, plasma is generated by the plasma reactor 1 to convert HC contained in the exhaust of the engine 71 into a more highly active reducing agent CH ₃ CHO and NO in the exhaust. Can be converted into NO _2, and the reduction of NOx in the downstream selective reduction catalyst 73 can be promoted.

FIG. 11 is a diagram showing an exhaust purification system 7B that directly purifies HC and NOx in the exhaust by the plasma reactor 1. In this system 7B, it is preferable to provide an oxidation catalyst 75 on the downstream side of the plasma reactor 1, as shown in FIG.
FIG. 10 illustrates an example in which the plasma reactor 1 is applied as an auxiliary device for promoting the reduction of NOx in the selective reduction catalyst 73. However, in the plasma reactor 1, HC and NOx in the exhaust can be directly decomposed into CO ₂ and N ₂ by generating plasma with higher energy than the system 7A shown in FIG. It is also possible to construct a system 7B that purifies HC and NO in the exhaust by such a plasma reactor 1.

The plasma reactor 1 described in detail above has the following effects.
(1) In the present embodiment, the internal electrode 32 is coaxially provided at the center of the outer peripheral electrode 31 extending along the exhaust flow direction, and the upstream end of the internal electrode 32 is connected via the first connection member 51. The first power supply plug 41 is held, the downstream end is held by the second power supply plug 42 via the second connection member 52, and the first power supply plug 41 and the second power supply plug 42 are held at the same potential of the high-voltage power supply. Connect to the pole. As a result, the difference in impedance can be reduced, so that the plasma intensity can be made uniform from the upstream side to the downstream side, and the time difference of plasma generation can be reduced.
By holding both ends of the linear or rod-like internal electrode 32 with power supply plugs 41, 42 provided in the exhaust pipe 2, the internal electrode 32 and the outer peripheral electrode 31 are not changed in distance. The position of 32 can be maintained at the center of the outer peripheral electrode 31. Therefore, it is possible to stably generate plasma having a uniform intensity from the upstream side to the downstream side.

  (2) In the present embodiment, the power supply plugs 41 and 42 are provided with sockets that are connected to the center electrode, and the connection members 51 are connected to the sockets by extending support shafts extending along a plane perpendicular to the flow direction of the exhaust gas. , 52 and the power supply plugs 41, 42 are connected. Conventionally, in order to fix the position and posture of the connection members 51 and 52 that connect the internal electrode 32 and the power supply plugs 41 and 42 in the exhaust pipe 2, the connection members 51 and 52 are connected to the outer electrode 31 via an insulating material. According to the present embodiment, the connection members 51 and 52 to which both ends of each internal electrode 32 are connected are directly held in the exhaust pipe 2 by the power supply plugs 41 and 42 when it is necessary to fix to the end portion. This eliminates the need for such components. Further, by connecting the support shafts of the connection members 51 and 52 to the sockets of the power supply plugs 41 and 42 having a positioning mechanism for restricting the movement along the extending direction, the inside of the exhaust pipe 2 of the connection members 51 and 52 Since the internal electrode 32 can be kept at the center of the outer peripheral electrode 31, the homogeneous plasma can be stably generated as described above.

  (3) In this embodiment, by connecting the support shaft to a socket having a rotation restricting mechanism for restricting the rotation of the connection members 51 and 52 around the support shaft, the connection members 51 and 52 in the exhaust pipe 2 are connected. Since the rotation can be prevented and the position of the internal electrode 32 can be kept at the center of the outer peripheral electrode 31, the homogeneous plasma can be stably generated as described above.

  (4) In this embodiment, the exhaust pipe 2 is formed along the surface of the power supply plugs 41 and 42 in the exhaust pipe 2 by forming the outer peripheral surface of the exhaust pipe 2 on the inner side of the power supply plugs 41 and 42 in an uneven shape. 2 and the peripheral electrode 31 can be prevented from being discharged, so that homogeneous plasma can be stably generated as described above.

As mentioned above, although one Embodiment of this invention was described, this invention is not restricted to this, A various deformation | transformation is possible.
For example, in the above embodiment, the example in which the support shaft 515 is elastically supported in the socket 416 by the coil spring 4164 has been described, but the present invention is not limited to this. For example, instead of the coil spring, a support shaft may be supported in the socket by an inner clip that is partially cut and can be elastically deformed in the same manner as the coil spring.

Moreover, the specific shape of the connection part of the 1st connection member 51 or the 2nd connection member 52 is not restricted to what is shown in FIG. For example, a connecting member 51A as shown in FIG. 12 may be used.
FIG. 12 is a view showing a modification of the connection member 51A.
The connecting portion 511A of the connection member 51A of the modified example is formed in a lattice shape, and connects the internal electrodes 32 of all the plasma discharge units 3 adjacent to each other. When the connection member 51A according to this modification is compared with the connection member 51 described with reference to FIG. 2, the connection member 51A according to the modification connects a larger number of internal electrodes 32. As indicated by “x” in FIG. 12, even when a part of the connecting portion 511A is broken, the electrical connection with the power supply plug 41 is not cut off, so that the durability is further improved. Can be a thing. However, the connecting member 51A of the modified example has a larger cross-sectional area, so that the pressure loss of the exhaust pipe 2 becomes larger.

Further, as shown in FIG. 13, a honeycomb structure 8 supporting a photocatalyst may be provided inside each plasma discharge unit 3. By providing such a honeycomb structure 8, it is possible to excite the photocatalyst using the plasma generated by the plasma discharge unit 3 and further promote exhaust purification. As a material for the photocatalyst, for example, titanium dioxide (TiO ₂ ) is used.

1 ... Plasma reactor (exhaust gas purification device)
DESCRIPTION OF SYMBOLS 2 ... Exhaust pipe 3 ... Plasma discharge unit 31 ... Peripheral electrode 32 ... Internal electrode 41 ... 1st electric power plug 416 ... Socket 4162 ... 2nd accommodating part (rotation control mechanism)
4164 ... Coil spring (elastic member, positioning mechanism)
42 ... 2nd electric power feeding plug 51 ... 1st connection member 511 ... Connection part 515 ... Support shaft 52 ... 2nd connection member 6 ... High voltage power supply

Claims (4)

A plurality of cylindrical outer peripheral electrodes provided along an exhaust flow direction in an exhaust pipe through which the exhaust gas of the internal combustion engine flows, and a plurality of linear or rod-like inner portions provided coaxially at the centers of the plurality of outer peripheral electrodes An exhaust purification device that purifies exhaust by plasma generated by applying a voltage between both electrodes,
A first power supply plug provided upstream of the plurality of outer peripheral electrodes in the exhaust pipe; and a second power supply plug provided downstream of the plurality of outer peripheral electrodes of the exhaust pipe;
The upstream end portions of the plurality of internal electrodes are held by the first power supply plug via a conductive first connection member, and the downstream end portions of the plurality of internal electrodes are conductive second connection members. Is held by the second power supply plug via
The exhaust gas purification apparatus, wherein the first power supply plug and the second power supply plug are connected to the same potential electrode of a high-voltage power supply. The first and second power supply plugs include a socket connected to the center electrode,
The first and second connecting members include a connecting portion that connects the end portions of the adjacent internal electrodes, and a support that extends from the connecting portion along a plane perpendicular to the flow direction of the exhaust and fits into the socket. With a shaft,
The exhaust purification device according to claim 1, wherein the socket has a positioning mechanism that restricts movement of the support shaft along the extending direction thereof.   The exhaust purification device according to claim 2, wherein the socket includes a rotation restricting mechanism that restricts rotation about the support shaft.   4. The exhaust emission control device according to claim 3, wherein an outer peripheral surface on an inner side of the exhaust pipe of the first and second power supply plugs is formed in an uneven shape.

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