JP2006063872A - High voltage wiring connection structure of exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent high voltage wiring from being removed due to displacement, etc. caused by vibration of an exhaust pipe when an exhaust emission control device is connected to a high voltage power source, and to prevent heat from being transferred to a covered part made of synthetic resin of the high voltage wiring due to high temperature. <P>SOLUTION: To connect a corona discharge electrode 2 of the exhaust emission control device 1 to the high voltage wiring 4, an electrode side terminal 22 is electrically connected to the high voltage wiring 4 by a coil spring 7 with flexible structure, and the corona discharge electrode 2 is connected to a connection end part of the high voltage wiring 4 with water resistance by a metal bellows 8, having the flexible structure, for covering its periphery. A cylindrical insulating member 9 made of rubber for electrically disconnecting the coil spring 7 and the bellows 8 without impairing flexibility thereof is interposed between the coil spring 7 and the bellows 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a connection structure of a high voltage wiring to an exhaust gas purification apparatus for an internal combustion engine using a high voltage.

  Treatment of fine particles contained in the exhaust gas of an internal combustion engine has become a major issue, and various exhaust gas purification devices have been proposed. As for particulates (PM) discharged from a diesel engine, a collecting device using a ceramic filter is conventionally known. However, recently, it has been studied to electrically collect and remove particulates. For example, there is a device for processing fine particles using corona discharge, and by applying a high voltage between a discharge electrode having a plurality of protrusions at the tip and a counter electrode to generate corona discharge, fine particles in exhaust Can be agglomerated electrostatically.

In this apparatus, a structure for connecting a high-voltage power supply placed in a vehicle compartment or an engine room to an exhaust purification device attached to an exhaust pipe becomes a problem. As a prior art relating to high-voltage wiring, there is Patent Document 1, which relates to an ignition plug that is screwed into a cylinder head of an internal combustion engine. A high-tension cord for supplying high-voltage power is fixed to the ignition plug with a cylindrical rubber, and a spring force The structure which connects to the head electrode of a spark plug using is disclosed. Specifically, an electrically insulating rubber cylinder is integrally bonded to the lower end of a high tension cord covered with an electrically insulating synthetic resin, and this cylinder is covered with an insulator of a spark plug. At this time, the high-voltage socket built into the lower end of the high tension cord and the head terminal of the spark plug are electrically connected using a coil spring and a plate spring, so that the high-pressure electromagnetic force generated by the ignition coil is securely connected to the spark plug. To be supplied to.
JP 2000-27746 A

 However, when the above connection structure is applied to an exhaust emission control device, the following problems occur. As in Patent Document 1, it is not easy to maintain a connection at a portion where displacement due to vibration is large, such as an exhaust pipe, simply by covering a rubber cylindrical portion integrated with the wiring on the electrode terminal. There is a risk that the voltage wiring may be shifted or disconnected. In addition, when used in an exhaust purification device, the exhaust becomes high temperature, and there is a concern that the high voltage wiring covered with the synthetic resin is thermally deformed or the rubber cylinder portion for fixing the insulator is burned out.

  Therefore, the present invention has a structure in which the high-voltage wiring is not detached due to displacement caused by vibration of the exhaust pipe when the exhaust purification device attached to the exhaust pipe is connected to the high-voltage power source. In order to avoid damage to the voltage wiring, an object is to have a structure in which heat is not transmitted to the covering portion made of synthetic resin.

  Claim 1 relates to a high-voltage wiring connection structure for supplying a high voltage to an electrode part of an exhaust gas purification device installed in an exhaust pipe of an internal combustion engine, and is flexible for electrically connecting a terminal of the electrode part and a high-voltage wiring. A conductive portion having a structure, a tubular heat-resistant member having a flexible structure covering the periphery of the conductive portion, a connection portion for connecting the end portion of the electrode portion and the end portion of the high-voltage wiring with water resistance, and conductive And an insulating part that is interposed between the connecting part and the connecting part and electrically cuts between the two without impairing the flexibility of the both.

  According to the said structure, since the cylindrical heat-resistant member of the flexible structure was used for the connection part, the displacement between the electrode part and high voltage wiring by the vibration of an exhaust pipe, etc. can be absorbed. Moreover, it can prevent that the heat | fever of an exhaust pipe is directly transmitted to the coating | coated part of wiring by interposing a cylindrical heat-resistant member. Electrical connection is ensured at the conductive portion of the flexible structure, and insulation between the connecting portion can be ensured by interposing an insulating portion. Therefore, it is possible to prevent the high voltage wiring from being disconnected, to maintain the connection with the electrode portion, and to prevent the high voltage wiring from being damaged by heat.

  According to a second aspect of the present invention, the connecting portion fixes one end of the flexible heat-resistant tubular heat-resistant member to the electrode portion, and inserts and fixes the high-voltage wiring through the sealing member in the other end opening.

  Preferably, the high-voltage wiring is inserted into the cylindrical heat-resistant member fixed to the electrode portion and connected to the electrode terminal, and the insertion opening is sealed with the sealing member, so that the electrode terminal portion is cut off from the external space. Can be prevented.

  Specifically, the conductive portion can be made of a spring-like conductor or a flexible conductor.

  Spring-like conductors such as coil springs and flexible conductors such as conductive rubber have a flexible structure that can follow displacement, so that electrical connection between the electrode terminals and the high-voltage wiring can be maintained. .

  Specifically, a metal bellows can be used as the flexible heat-resistant tubular heat-resistant member.

  Since the displacement caused by vibration can be absorbed by the bellows structure of the metal bellows, the above-described effect of preventing the disconnection of the high voltage wiring can be easily obtained.

  Preferably, the metal bellows is made of stainless steel.

  Heat resistance can be increased by adopting stainless steel as a material that does not easily transmit heat to the high-voltage wiring.

  Specifically, the insulating portion is formed of a cylindrical elastic body that covers the periphery of the conductive portion. Or it can also be set as the gel-like insulating material or insulating gas with which it fills between an electroconductive part and a connection part.

  By covering the conductive portion with an insulating member having a flexible structure, for example, a cylindrical body made of an elastic material such as rubber, the conductive portion and the connecting portion can be insulated from each other without impairing the flexibility. The same effect can be obtained by using gel or gas.

  The exhaust emission control device according to claim 7, which has a discharge electrode and a ground electrode that are opposed to each other in the exhaust passage as an electrode portion, and generates a discharge by applying a high voltage between both electrodes to charge the exhaust particulates. -Aggregate.

  When a high voltage is applied between the discharge electrode and the ground electrode to generate a discharge, the fine particles in the exhaust gas passing through the discharge space are charged, move by an electrostatic force, and aggregate. Aggregated particles are less likely to become suspended particles, so the influence on the environment is small, and they can be easily collected.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows a schematic configuration of an exhaust emission control device 1 to which the present invention is applied. FIG. 1 shows a connection structure with a high voltage wiring 2 which is a feature of the present invention, and FIG. Shown in (a), (b). In FIG. 3A, the exhaust purification device 1 is disposed at the lower part of the vehicle, and is connected by a high voltage power source 5 and a high voltage wiring 4 disposed at the rear of the vehicle. As shown in FIG. 3 (b), the exhaust purification device 1 is attached to the exhaust pipe 6 of the diesel engine E so that the exhaust gas flows through the exhaust purification device 1. Exhaust gas is purified by applying a high voltage between 2 and 3 to generate discharge. The exhaust pipe 6 is provided with a known exhaust purification catalyst C upstream of the exhaust purification device 1 and a muffler M downstream. However, the present invention is not limited to this configuration.

  As shown in FIG. 2, the exhaust emission control device 1 according to the present embodiment is configured as an agglomerator of particulates in exhaust gas, and has a housing 11 having a diameter larger than the exhaust pipe 2 of the engine and a wall of the housing 11. A corona discharge electrode 2 (hereinafter referred to as a discharge electrode) to be fixed and a ground electrode 3 made of a conductive net installed in the housing 11 are provided. Both ends of the housing 11 are connected to the exhaust pipe 6 as reduced diameter portions. The ground electrode 3 has a disk shape, is disposed across the passage so as to be orthogonal to the exhaust flow, and an outer peripheral edge is fixed to the inner peripheral wall of the housing 11. The conductive net that becomes the housing 11 and the ground electrode 3 is made of a conductive material such as stainless steel and is electrically grounded. In this configuration, the inner peripheral wall of the housing 11 also functions as a ground electrode.

  The discharge electrode 2 has a rod shape, and the lower half is positioned as an exhaust passage in the housing 11 serving as an exhaust passage, and the distal end portion 21 protruding from the cylindrical insulator 22 is bent in an L shape and positioned downstream. It faces the grounding electrode 3 that performs. For example, the tip portion 21 of the discharge electrode 2 has a shape in which a plurality of protrusions protrude in the radial direction. The number and shape of the protrusions can be appropriately set as necessary. Preferably, when a large number of protrusions are arranged radially, the discharge rate is increased and the effect of generating corona discharge evenly in the housing 11 is obtained. It is done. The upper half of the discharge electrode 2 protrudes out of the housing 11 and is screwed to the wall of the housing 11 by a screw portion on the outer periphery of the housing 23 that holds the center portion. The housing 23 is made of stainless steel (SUS) or the like.

  Next, a connection structure with the high voltage wiring 4 which is a characteristic part of the present invention will be described. In FIG. 1, an electrode-side terminal 24 is provided at the upper end of the discharge electrode 2, and faces the metal wire 41 exposed at the lower end of the high-voltage wiring 4. The electrode-side terminal 24 and the metal wire 41 are electrically connected by a coil spring 7 as a conductive portion of the flexible structure, and have a flexible structure so as to cover the periphery and the lower end portion of the high voltage wiring 4 and the upper end portion of the insulator 22. A bellows 8 is disposed as a cylindrical heat-resistant member. An insulating member 9 having a flexible structure is disposed inside the bellows 8 as an insulating portion that electrically cuts off from the coil spring 7.

  The bellows 8 is formed by forming a metal plate such as stainless steel (SUS) into a bellows shape that is difficult to transmit heat. The bellows 8 absorbs the displacement due to the expansion and contraction of the bellows, and uses the surface area to radiate heat from the exhaust pipe 6 to the atmosphere, making it difficult to transmit to the high voltage wiring 4. Therefore, the number and size of the bellows may be set as appropriate so as to obtain a necessary effect. The lower end of the bellows 8 is fixed to the housing 23, and the upper end is located on the outer periphery of the high voltage wiring 4 with a gap.

  The insulating member 9 having a flexible structure is made of a cylindrical elastic body such as silicon (Si) rubber, and can be deformed following the bellows 8. Thereby, between the bellows 8 and the coil spring 7 can be electrically interrupted without impairing the flexibility. The upper end of the insulating member 9 is joined to the inner periphery of the upper end opening of the bellows 8, and the gap with the high voltage wiring 4 is sealed by the sealing member 81 fitted inside thereof. The sealing member 81 is made of, for example, silicon (Si) rubber.

  As the conductive portion of the flexible structure, a spring-like conductor other than the coil spring, or a flexible conductor such as conductive rubber can be used.

  The operation of the exhaust emission control device 1 having the above configuration will be described. In FIG. 2, when a negative DC high voltage (for example, −20 KV) is applied to the discharge electrode 2 from the high voltage power source 5 of FIG. 3, a corona discharge is generated in the vicinity of the tip 21 of the discharge electrode 2, and electrons are emitted. Is done. As a result, oxygen with high electron affinity is negatively ionized and adheres to nearby exhaust particulates (particulates) to be negatively charged. The exhaust fine particles move to the ground electrode 3 side by the Coulomb force and the gas flow, and are aggregated and coarsened. Aggregated particles tend to fall by their own weight due to coarsening, and are less likely to be suspended particles by diffusing into the atmosphere, so the impact on the environment is small. Preferably, a filter is installed downstream to collect the aggregated particles that have passed through the aggregator, thereby preventing release to the atmosphere.

  Further, as a connection structure between the exhaust emission control device 1 and the high voltage wiring 4, a bellows 8 that couples the two is arranged, and the high voltage wiring 4 is fitted into the opening of the bellows 8 via the sealing member 81 and the insulating member 9. Since the bellows 8 has a bellows structure, the displacement due to the vibration of the exhaust pipe 6 is absorbed, and the high voltage wiring 4 is prevented from being detached. Further, the heat from the exhaust pipe 6 is radiated to the atmosphere using the surface area of the bellows portion of the bellows 8 and is connected to the high voltage wiring 4 via a plurality of members 81 and 9 at the upper end portion where the temperature is lowered. The resin coating portion of the high voltage wiring 4 is not damaged by heat.

  As described above, a structure in which displacement or heat due to vibration is not applied to the high-voltage wiring 4 can be obtained, and it can be used at a site such as the exhaust pipe 6 where vibration is generated or heat is likely to be generated. At this time, an insulating member 9 having a flexible structure is disposed between the coil spring 7 and the bellows 8 that electrically connect the high voltage wiring 4 and the electrode side terminal 24, and the two are electrically disconnected. In addition, since the inner space of the bellows 8 is shut off from the outside by the sealing member 81 and the water resistance of the electrical connection portion is increased, the exhaust gas purification apparatus 1 can perform the treatment of the fine particles satisfactorily.

The second embodiment of the present invention will be described with reference to FIG. The basic configuration of this embodiment is the same as that of the first embodiment, and a description thereof is omitted. In the present embodiment, an insulating member 91 having a flexible structure other than the cylindrical elastic body is used as an insulating member that is disposed between the coil spring 7 and the bellows 8 and electrically cuts between the two. Examples of the insulating member 91 having such a flexible structure include a gel-like insulating material such as Si (silicon) gel, and an insulating gas such as SF ₆ (sulfur fluoride gas) or chlorofluorocarbon gas. Insulating effect is exhibited by filling the material.

  Also according to the present embodiment, the coil spring 7 and the bellows 8 are electrically disconnected, and the same effect as in the first embodiment can be obtained.

  In the above embodiment, the aggregator using corona discharge is used as the exhaust gas purification device. However, the connection structure of the present invention is not limited to this, and the exhaust gas purification device using plasma discharge or other high voltage is not limited to this. As long as it is a high voltage wiring for applying voltage, it is preferably used in any case, and the same effect can be obtained.

It is a schematic block diagram which shows the high voltage wiring connection structure of the exhaust gas purification apparatus in the 1st Embodiment of this invention. 1 is an overall configuration diagram of an exhaust emission control device to which a connection structure according to a first embodiment is applied. (A) is a figure which shows the vehicle-mounted example of the exhaust gas purification apparatus to which this invention is applied, (b) is a figure which shows the exhaust passage structure example which attached the exhaust gas purification apparatus to which this invention is applied. It is a schematic block diagram which shows the high voltage wiring connection structure of the exhaust gas purification apparatus in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust purification apparatus 11 Housing 2 Corona discharge electrode 21 Tip part 22 Insulator 23 Housing 24 Electrode side terminal 3 1st ground electrode 4 High voltage wiring 41 Metal wire 5 High voltage power supply 6 Exhaust pipe 7 Coil spring (conductive part)
8 Bellows (connecting part, flexible heat-resistant tubular member)
81 Sealing member (connection part)
9 Cylindrical insulating member (insulating part)

Claims (7)

A high voltage wiring connection structure for supplying a high voltage to an electrode part of an exhaust gas purification device installed in an exhaust pipe of an internal combustion engine,
A conductive part having a flexible structure for electrically connecting the terminal of the electrode part and the high-voltage wiring;
A connecting portion that has a tubular heat-resistant member having a flexible structure covering the periphery of the conductive portion and connects the end portion of the electrode portion and the end portion of the high-voltage wiring with water resistance;
A high-voltage wiring connection structure for an exhaust emission control device, comprising: an insulating portion that is interposed between the conductive portion and the coupling portion and electrically cuts between the two without impairing flexibility of the two. .   The exhaust purification device according to claim 1, wherein the connecting portion fixes one end of the flexible heat-resistant tubular heat-resistant member to the electrode portion, and inserts and fixes the high-voltage wiring through the sealing member in the other end opening. High voltage wiring connection structure.   The high voltage wiring connection structure for an exhaust emission control device according to claim 1 or 2, wherein the conductive portion is made of a spring-like conductor or a flexible conductor.   The high voltage wiring connection structure for an exhaust emission control device according to any one of claims 1 to 3, wherein the flexible heat-resistant tubular heat-resistant member is a metal bellows.   The high voltage wiring connection structure for an exhaust gas purification apparatus according to claim 4, wherein the metal bellows is made of stainless steel.   6. The insulating member according to claim 1, wherein the insulating portion is formed of a cylindrical elastic body covering the periphery of the conductive portion, or a gel-like insulating material or insulating gas filled between the conductive portion and the connecting portion. A high voltage wiring connection structure of the exhaust gas purification apparatus described.   The electrode part of the exhaust purification device has a discharge electrode and a ground electrode that are arranged opposite to each other in the exhaust passage, and a high voltage is applied between both electrodes to generate a discharge to charge and aggregate exhaust particulates. The high-voltage wiring connection structure for an exhaust emission control device according to any one of claims 1 to 6.

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