JP2012062832A - Catalytic converter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalytic converter device that prevents the efficiency of heating a catalyst carrier from degradation caused by droplets generated in an exhaust pipe.SOLUTION: The catalyst carrier 14 carrying a catalyst is held by a holding member 26 in a case cylinder 28. Electrodes 16A and 16B are stuck to the catalyst carrier 14 at an electrode accommodating part 24 between two holding members 26. Insulation powder 30 is filled in the electrode accommodating part 24.

Description

  The present invention relates to a catalytic converter device provided in an exhaust pipe of an internal combustion engine.

  In a catalytic converter device provided in an exhaust pipe for purifying exhaust gas generated in an internal combustion engine, for example, as described in Patent Document 1, a metal catalyst carrier supporting a catalyst is energized to raise the temperature, Some of them have a catalytic effect.

  Incidentally, in the structure described in Patent Document 1, an interlam mat is disposed in contact with the periphery of an electrode for energizing the metal catalyst carrier. In general, on the upstream side of the metal catalyst carrier, moisture generated by combustion of the internal combustion engine may be scattered as condensed water. Water droplets generated at this time are absorbed by the interlam mat, and the interlam mat passes between the electrodes. If short-circuited, the heating efficiency of the catalyst carrier may be reduced. In order to avoid such a short circuit, for example, it may be possible to dispose the interlam mat in a non-contact manner with the electrodes. However, if water droplets adhere to the periphery of the electrodes, there is a possibility that the electrodes are short-circuited by the water droplets. is there.

Japanese Utility Model Publication No. 6-47625

  In view of the above facts, an object of the present invention is to obtain a catalytic converter device that can suppress a decrease in the heating efficiency of the catalyst carrier due to water droplets generated in the exhaust pipe.

  In the first aspect of the present invention, a catalyst carrier for purifying exhaust gas exhausted from the internal combustion engine is carried, the catalyst carrier is heated by energization, and the catalyst carrier is accommodated in a cylindrical shape. And a cylindrical body attached to the exhaust pipe, a pair of electrodes provided on the outer peripheral surface of the catalyst carrier for energizing the catalyst carrier, and having an insulating property, disposed between the cylindrical body and the catalyst carrier. A holding member that holds the catalyst carrier in the cylinder by elasticity; and an insulating member that is disposed between the cylinder and the holding member and the electrode and insulates the electrode from the cylinder and the holding member.

  In this catalytic converter device, when the catalyst carrier is energized through the electrodes and heated and heated, the purification effect by the supported catalyst can be exhibited more quickly. In addition, the catalyst carrier is attached to the exhaust pipe via the holding member and the cylinder, and the holding member has insulating properties, so that the catalyst carrier and the cylinder are short-circuited through the holding member. There is no.

  The exhaust gas may contain moisture generated by combustion of the internal combustion engine, and this moisture may be scattered to generate water droplets. In this invention, the insulating member is arrange | positioned between the cylinder and the holding member, and the electrode, and the electrode is insulated with respect to the cylinder and the holding member. That is, since a short circuit between the electrode and the cylinder and between the electrode and the holding member is prevented, a decrease in the heating efficiency of the catalyst carrier can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the present invention, a terminal provided corresponding to each of the electrodes and penetrating the cylindrical body, and the flexible terminal and the electrode are provided. A conductive wire member that is electrically connected, and the insulating member insulates the conductive wire member from the cylindrical body and the holding member.

  The electrode can be energized through the terminal and the conductor member. And since the insulating member is insulating the conducting wire member with respect to a cylinder and a holding member, the short circuit between a conducting wire member and a cylinder and between a conducting wire member and a holding member is also prevented.

  In the invention of claim 3, in the invention of claim 2, the holding member is divided and provided on the upstream side and the downstream side in the exhaust flow direction from the electrode, and the insulating member is The insulating powder is filled between the holding member on the upstream side and the downstream side and between the catalyst carrier or the electrode and the cylindrical body.

  Thus, the required insulation is ensured with a simple structure in which the insulating powder is filled between the upstream holding member and the downstream holding member and between the catalyst carrier or electrode and the cylinder. it can. Moreover, since the insulating powder can be deformed as a whole, even if relative movement between the cylinder and the catalyst carrier (deviation due to thermal expansion, vibration from the vehicle, etc.) occurs, it can be absorbed.

  According to a fourth aspect of the present invention, in the second aspect of the present invention, the insulating member is a covering member that has flexibility and covers the surface of the electrode and the outer surface of the conducting wire member.

  Thus, the required insulation can be ensured with a simple structure in which the surface of the electrode and the outer surface of the conductor member are covered with the covering member. In addition, since the covering member is flexible, even if relative movement between the cylinder and the catalyst carrier (deviation due to thermal expansion, vibration from the vehicle, etc.) occurs, it can be absorbed.

  Since the present invention has the above configuration, it is possible to suppress a decrease in the heating efficiency of the catalyst carrier due to water droplets generated in the exhaust pipe.

1 is a cross-sectional view showing a catalytic converter device according to a first embodiment of the present invention in a cross section including a center line in an attached state to an exhaust pipe. (A) is sectional drawing which shows the catalytic converter apparatus of 2nd Embodiment of this invention in the cross section containing a centerline in the attachment state to an exhaust pipe, (B) is a partial catalytic converter apparatus of 2nd Embodiment. FIG.

  FIG. 1 shows a catalytic converter device 12 according to a first embodiment of the present invention attached to an exhaust pipe 10.

  As shown in FIG. 1, the catalytic converter device 12 is made of a material having conductivity and rigidity (a conductive ceramic, a conductive resin, a metal, or the like can be applied, but in this embodiment, a conductive ceramic is used in particular). It has a catalyst carrier 14 formed. The catalyst carrier 14 is formed in a columnar shape or a cylindrical shape in which the surface area of the material is increased by configuring a thin plate having a honeycomb shape or a wavy shape into a spiral shape or a concentric shape, and a catalyst (platinum) is formed on the surface. , Palladium, rhodium, etc.) are attached. The catalyst has an action of purifying harmful substances in the exhaust gas flowing in the exhaust pipe 10 (the flow direction is indicated by an arrow F1). Note that the structure for increasing the surface area of the catalyst carrier 14 is not limited to the honeycomb shape or the wave shape described above.

  Two electrodes 16A and 16B are attached to the catalyst carrier 14, and terminals 18A and 18B are connected to the electrodes 16A and 16B via conductor members 20A and 20B, respectively. In each of the terminals 18A and 18B, an insulating glass coat layer 34 and a ceramic coat layer 36 cover the periphery of the central core member 32, and the outer periphery thereof is covered with a metal cover cylinder 38. The core material 32 of the terminals 18 </ b> A and 18 </ b> B penetrates the case cylinder 28.

  The end portions of the terminals 18A and 18B are connected to the electrodes 16A and 16B via conducting wire members 20A and 20B made of a conductive material such as metal. The conducting wire members 20A and 20B are formed in, for example, a zigzag shape or a spiral shape so as to have flexibility, and when the case cylinder 28 and the catalyst carrier 14 are relatively moved as described later, It is possible to absorb this relative movement. The catalyst carrier 14 can be heated by energizing the catalyst carrier 14 from the terminals 18A and 18B through the conductor members 20A and 20B. By heating the catalyst supported on the surface by this heating, the catalyst purification action can be exhibited quickly even immediately after the engine is started.

  A holding member 26 formed in an approximately cylindrical shape with an insulating material is disposed on the outer periphery of the catalyst carrier 14. Further, a case cylinder 28 formed in a substantially cylindrical shape with a metal such as stainless steel is disposed on the outer periphery of the holding member 26. In other words, the catalyst carrier 14 is accommodated inside the substantially cylindrical case cylinder 28, and the catalyst carrier 14 is cased by the holding member 26 disposed between the case cylinder 28 and the catalyst carrier 14. The cylinder 28 is held concentrically (center line CL). Since the insulating holding member 26 is disposed between the catalyst carrier 14 and the case cylinder 28, the flow of electricity from the catalyst carrier 14 to the case cylinder 28 is prevented.

  The holding member 26 also has a predetermined elasticity. Since the case expansion body 28 made of metal and the catalyst carrier 14 made of conductive ceramic have different linear expansion coefficients, the amount of expansion due to the heat of the exhaust gas passing through the exhaust pipe 10 and the current heating to the catalyst carrier 14 is different. However, the difference in expansion amount is absorbed by the elasticity of the holding member 26. Further, even when vibration is input through the exhaust pipe 10, the holding member 26 absorbs a positional deviation between the case cylinder 28 and the catalyst carrier 14 while exhibiting a buffering action. The material of the holding member 26 is not limited as long as it has the above-described insulating properties and elasticity. However, as an example of the material, a fiber mat is preferable, and an interlam mat, mullite, or the like is also applicable. .

  In the present embodiment, the holding member 26 is divided into two in the axial direction so as not to contact the electrodes 16A and 16B, and an upstream holding member 26P and a downstream holding member 26Q are configured. And the electrode accommodating part 24 which accommodates electrode 16A, 16B is formed between the upstream holding member 26P and the downstream holding member 26Q. The holding member 26 and the electrodes 16A and 16B are not in contact with each other.

  Further, as can be seen from FIG. 1, when the holding member 26 is viewed as a whole, the catalyst carrier 14 and the holding member 26 are formed to have substantially the same length in the axial direction, and the upstream end surface 14A of the catalyst carrier 14 and The upstream end surface 26A of the holding member 26 is substantially flush. Similarly, the downstream end surface 14B of the catalyst carrier 14 and the downstream end surface 26B of the holding member 26 are substantially flush with each other.

  The holding member 26 may be formed in a substantially cylindrical shape continuous from the upstream end face 26A to the downstream end face 26B without being divided into two as described above. In this case, the electrode accommodating portion 24 can be configured as a hole that penetrates the holding member 26 in the thickness direction at a position corresponding to each of the electrodes 16A and 16B.

  The electrode housing portion 24 is filled with an insulating powder 30. The insulating powder 30 is a member having insulating properties, flexibility (deformability), heat resistance, and water repellency. In the present embodiment, the electrode accommodating portion 24 is filled in a powder state. Examples of the insulating powder 30 include powdered talc (talc, silicate mineral) and the like. Filling the electrode housing portion 24 with such insulating powder 30 insulates the electrodes 16A and 16B from the case cylinder 28 and the electrodes 16A and 16B from the holding member 26. Has been. Further, the insulating powder 30 covers the periphery of the conductor members 20A and 20B, between each of the conductor members 20A and 20B and the case cylinder 28, and between each of the conductor members 20A and 20B and the holding member 26. They are insulated.

  Next, the operation of the catalytic converter device 12 of this embodiment will be described.

  As shown in FIG. 1, the catalytic converter device 12 is attached so that its case cylinder 28 is concentric with the exhaust pipe 10 in the middle of the exhaust pipe 10, and the exhaust passes through the inside of the catalyst carrier 14. At this time, harmful substances in the exhaust gas are purified by the catalyst supported on the catalyst carrier 14. In the catalytic converter device 12 of this embodiment, the catalyst carrier 14 is heated by energizing the catalyst carrier 14 by the terminals 18A and 18B, the conductor members 20A and 20B, and the electrodes 16A and 16B, thereby heating the catalyst carrier 14. The temperature can be raised and the purification action can be exerted more quickly. For example, when the temperature of the exhaust gas is low, such as immediately after starting the engine, the catalyst purification performance in the initial stage of engine starting can be ensured by conducting energization heating to the catalyst carrier 14 in advance.

  Since moisture is contained in the exhaust, the moisture in the exhaust pipe 10 is condensed on the upstream side of the catalytic converter device 12 to form water droplets. Then, since the water is scattered downstream by the flow of exhaust gas, water droplets may reach the electrode accommodating portion 24 through the outer peripheral surface of the catalyst carrier 14 (between the catalyst carrier 14 and the holding member 26). Alternatively, the catalyst carrier 14 and the holding member 26 may absorb water and the moisture may ooze out into the electrode housing portion 24. Further, gaseous moisture (water vapor) may pass through the catalyst carrier 14 together with the exhaust gas and reach the electrode housing portion 24. The water vapor is liquefied around the electrodes 16A and 16B having a low temperature, and may adhere to the surfaces of the electrodes 16A and 16B as liquid moisture.

  Here, assuming a configuration in which the electrode housing portion 24 is not filled with the insulating powder 30, each of the electrodes 16 </ b> A and 16 </ b> B and the case cylinder 28 are short-circuited with moisture due to moisture that has entered the electrode housing portion 24. Or, each of the electrodes 16A and 16B and the holding member 26 containing moisture may be short-circuited, so that the insulation resistance between the electrodes 16A and 16B may decrease. When the insulation resistance between the electrodes 16A and 16B is thus reduced, the amount of current supplied to the catalyst carrier 14 is reduced.

  In the catalytic converter device 12 of the present embodiment, the electrode accommodating portion 24 is filled with the insulating powder 30 and is held between each of the electrodes 16A and 16B and the case cylinder 28 and with each of the electrodes 16A and 16B. The member 26 is insulated. Therefore, it is possible to suppress a decrease in insulation resistance between the electrodes 16A and 16B due to moisture that has entered the electrode housing portion 24.

  In addition, since the insulating powder 30 of the present embodiment is filled in the electrode housing portion 24 and there is no gap (void) in the electrode housing portion 24, a space for moisture to enter does not occur. . In addition, the insulating powder 30 has water repellency, and the insulating powder 30 itself is also prevented from absorbing water. As described above, since the insulating powder 30 does not absorb water, the insulation resistance of the electrodes 16A and 16B is also prevented from being lowered by the moisture of the insulating powder 30. As a result, the amount of current supplied to the catalyst carrier 14 can be secured, and the heating efficiency of the catalyst carrier 14 can be maintained high.

  The insulating powder 30 also has flexibility and can be deformed as a whole. Therefore, the difference between the heat of exhaust gas passing through the exhaust pipe 10 and the expansion amount due to energization heating to the catalyst carrier 14 and the relative movement between the case cylinder 28 and the catalyst carrier 14 due to the input of vibration through the exhaust pipe 10 are as follows. It is absorbed not only by the elasticity of the holding member 26 but also by deformation of the insulating powder 30.

  Further, the insulating powder 30 is filled in the electrode accommodating portion 24, so that each of the conductor members 20A and 20B and the case cylinder 28 and each of the conductor members 20A and 20B and the holding member 26 are filled. They are insulated. Therefore, it is possible to suppress a decrease in insulation resistance between the conductor members 20A and 20B due to moisture that has entered the electrode housing portion 24.

  FIG. 2A shows a catalytic converter device 52 according to a second embodiment of the present invention. In FIG. 2B, the catalytic converter device 52 is shown partially enlarged. In the second embodiment, the same components and members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The catalytic converter device 52 of the second embodiment has covering members 54, 56, and 58 instead of the insulating powder 30 according to the first embodiment. The covering member 54 is covered in a thin film shape so as to cover the surfaces of the electrodes 16 </ b> A and 16 </ b> B (the outer peripheral surface of the catalyst carrier 14) in the electrode housing portion 24. Similarly, in the electrode accommodating portion 24, the covering member 56 covers the inner peripheral surface of the case cylinder 28, the downstream end surface 26C of the upstream holding member 26P, and the upstream end surface 26D of the downstream holding member 26Q. The covering member 56 covers the outside of the conductor members 20A and 20B, respectively.

  All of the covering members 54, 56, and 58 are made of an insulating material (for example, a black body coat). In particular, the covering member 58 has a predetermined elasticity (flexibility), and the resistance to deformation of the conductor members 20A and 20B is reduced to follow the deformation.

  Also in the catalytic converter device 52 of the second embodiment configured as described above, the covering member 54 allows the electrodes 16A, 16B and the case cylinder 28, and the electrodes 16A, 16B and the holding member 26, respectively. Is insulated. Further, the covering member 56 also insulates between the electrodes 16A and 16B and the case cylinder 28 and between the electrodes 16A and 16B and the holding member 26. Therefore, it is possible to suppress a decrease in insulation resistance between the electrodes 16A and 16B due to moisture that has entered the electrode housing portion 24.

  Further, in the catalytic converter device 52 of the second embodiment, the covering member 58 causes the conductor members 20A and 20B to be connected to the case cylinder 28 and the conductor members 20A and 20B to the holding member 26. Insulated. Therefore, it is possible to suppress a decrease in insulation resistance between the conductor members 20A and 20B due to moisture that has entered the electrode housing portion 24.

  In addition, since the covering member 58 has elasticity and easily follows the displacement and deformation of the conductor members 20A and 20B, the displacement and deformation of the conductor members 20A and 20B are not hindered.

  The covering members 54, 56, and 58 may have the required insulating properties and heat resistance to such an extent that they do not inadvertently deteriorate due to heat generated by the exhaust. As 58, it is desired to have a structure having a predetermined elasticity. For example, if a black body coat containing manganese and metal is used for the covering member 58, manganese and metal are chemically bonded, and the linear expansion coefficient is relatively close to that of the metal, so that the displacement of the conductor members 20A and 20B and The followability to deformation is higher than that of a general glass coat or the like.

  In the second embodiment, even when the covering member 56 is not provided, the covering member 54 insulates between the electrodes 16A and 16B and the case cylinder 28 and between the electrodes 16A and 16B and the holding member 26. Similarly, the insulation between the electrodes 16A and 16B and the case cylinder 28 and between the electrodes 16A and 16B and the holding member 26 is also insulated only by the covering member 56. That is, even if only one of the covering members 54 and 56 is provided, the above-described effect of suppressing the decrease in the insulation resistance between the electrodes 16A and 16B due to the moisture that has entered the electrode housing portion 24 is achieved. Play. However, the vicinity of the covering member 56 is farther from the catalyst carrier 14 than the covering member 54, and the gas moisture is easily liquefied because the temperature is low. As described above, the covering member 56 covers the portion where the liquid moisture easily adheres, so that the decrease in the insulation resistance due to the moisture that has entered the electrode housing portion 24 can be more effectively suppressed. On the other hand, in the configuration in which the covering member 56 is omitted, the required insulation can be secured with a simpler structure.

DESCRIPTION OF SYMBOLS 10 Exhaust pipe 12 Catalytic converter apparatus 14 Catalyst carrier 16A, 16B Electrode 18A, 18B Terminal 20A, 20B Conductive member 24 Electrode accommodating part 26 Holding member 28 Case cylinder 30 Insulating powder 52 Catalytic converter apparatus 54, 56, 58 Cover member CL center line

Claims (4)

A catalyst carrier that carries a catalyst for purifying exhaust gas discharged from the internal combustion engine and is heated by energization;
A cylindrical body that is formed in a cylindrical shape and contains the catalyst carrier therein and is attached to the exhaust pipe;
A pair of electrodes provided on the outer peripheral surface of the catalyst carrier for energizing the catalyst carrier;
A holding member that has insulation and is disposed between the cylinder and the catalyst carrier and elastically holds the catalyst carrier in the cylinder;
An insulating member disposed between the cylinder and the holding member and the electrode, and insulating the electrode from the cylinder and the holding member;
A catalytic converter device. A terminal provided corresponding to each of the electrodes and penetrating the cylindrical body;
A conducting wire member having flexibility and electrically connecting the terminal and the electrode;
Have
The catalytic converter device according to claim 1, wherein the insulating member insulates the conducting wire member from the cylindrical body and the holding member. The holding member is divided and provided on the upstream side and the downstream side in the flow direction of the exhaust gas from the electrode,
The catalytic converter device according to claim 2, wherein the insulating member is an insulating powder filled between the upstream and downstream holding members and between the catalyst carrier or the electrode and the cylindrical body. .   The catalytic converter device according to claim 2, wherein the insulating member is a covering member that has flexibility and covers a surface of the electrode and an outer surface of the conducting wire member.

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