JP5162303B2 - Catalytic device - Google Patents

Description

  The present invention relates to a catalyst device for purifying exhaust gas of an internal combustion engine.

Conventionally, a catalytic converter in which a catalyst carrier of an exhaust gas purification catalyst having a honeycomb structure is accommodated in a cylindrical container is known (for example, see Patent Document 1). In this catalytic converter, a ceramic mat as a buffer material is wound around a catalyst carrier, and this is accommodated in a container made of stainless steel (for example, JIS SUS430). In this catalytic converter, the catalyst carrier is held in the container by the repulsive force of the mat. However, when the catalytic converter is exposed to high-temperature exhaust gas, the stainless steel container expands, the force acting between the mat and the container is weakened, and the force holding the catalyst carrier is attenuated. There may be a clearance between the container and the container. Therefore, a holding member constituted by joining a plurality of types of stainless steel materials having different linear expansion coefficients is disposed between the container for housing the catalyst carrier and the catalyst carrier, and the container is deformed by deforming the holding member. The structure which absorbs the clearance which arises by expansion | swelling of this was proposed (for example, refer patent document 2).
JP-A-2-43955 Japanese Patent No. 3845873

As described above, since the catalyst for purifying the exhaust gas is exposed to the high-temperature exhaust gas, the influence due to the expansion of the container accommodating the catalyst carrier must be taken into consideration. For this reason, in the configuration disclosed in Patent Document 2, the catalyst carrier is held by using a holding member having a complicated shape. However, it is possible to create a holding member having such a shape according to the size of the catalyst carrier. This is not easy, and there is a problem that the number of manufacturing steps increases.
In view of the above-described problems, the present invention provides a catalyst device configured to accommodate a catalyst carrier in a container, and has a configuration capable of stably holding the catalyst carrier even in a high temperature environment. The object is to realize without complicating the configuration.

In order to solve the above problems, the present invention provides a ceramic catalyst carrier (11) carrying a catalyst for purifying exhaust gas from an internal combustion engine, an outer cylinder (13) for housing the catalyst carrier (11) , It comprises a mat (12) which is interposed between the outer cylinder (13) and said catalyst carrier (11), the outer cylinder (13) remote sensing expansion coefficient lower by SUS430 stainless steel, pure titanium , either titanium alloys and titanium compounds, or pure titanium, is composed of any alloy containing one or more titanium alloys and titanium compounds as the material, the outer cylinder (13), upstream in the flow direction of the exhaust gas The exhaust pipe (50) of the internal combustion engine is formed together with the upstream exhaust pipe (50) by being joined to the upstream exhaust pipe (50) positioned on the side, and the outer cylinder (13) End of (13A) to the end (13B) on the outlet side have the same diameter, and the longitudinal dimensions of the catalyst carrier (11) and the mat (12) are in the longitudinal direction of the outer cylinder (13). The catalyst carrier (11) and the mat (12) are smaller than the size, and are held so as to be disposed at positions retracted from both ends of the outer cylinder (13). The upstream exhaust pipe (50) Any one of pure titanium, a titanium alloy and a titanium compound, or an alloy containing one or more of pure titanium, a titanium alloy and a titanium compound, and in the outer cylinder (13), the catalyst carrier (11) and The mat (12) is accommodated in a compressed state, and the catalyst carrier (11) is applied by a repulsive force acting on the catalyst carrier (11) and the outer cylinder (13) of the mat (12) that is press-fitted. It held, characterized by.
According to this configuration, the outer cylinder that accommodates the ceramic catalyst carrier and the mat is made of a material having a lower linear expansion coefficient than that of a stainless steel material (for example, JIS SUS430). The amount of deformation of the outer cylinder due to expansion is small even when exposed to the exhaust gas. As a result, a catalyst device capable of holding the catalyst carrier in the same manner as at room temperature can be realized without the outer cylinder and the mat interposed between the outer cylinder and the catalyst carrier being separated from each other. . And, by making the material used for the outer cylinder of this catalyst device a material whose coefficient of linear expansion is lower than that of stainless steel, it is easy to use without complicated structure, without increasing manufacturing man-hours and complicated mechanism. Is feasible. In addition, since the amount of deformation of the outer cylinder accompanying a rise in temperature is kept small, there is an advantage that the allowable accuracy range is widened and the degree of freedom in design and manufacturing is increased.
In the above configuration, the outer cylinder (13) is joined to the upstream exhaust pipe (50) and the downstream exhaust pipe (55) located on the downstream side, so that these upstream exhaust pipes ( 50) and a downstream exhaust pipe (55) constitute an exhaust path (140) of the internal combustion engine, and the downstream exhaust pipe (55) is connected to the downstream end (13B) of the outer cylinder (13). A straight pipe having the same diameter and butt-joined to the end (13B), and the downstream exhaust pipe (55) is pure titanium, a titanium alloy and a titanium compound, or pure titanium, a titanium alloy and titanium. It is good also as what was comprised with the alloy containing any one or more of a compound.

In the above structure, the material constituting the outer cylinder (13), pure titanium, or titanium alloys and titanium compounds, or pure titanium, and an alloy containing any one or more titanium alloys and titanium compounds. Since these materials have a lower coefficient of linear expansion than stainless steel materials such as JIS SUS430, the amount of deformation due to expansion is small even when exposed to high-temperature exhaust gas during use. For this reason, it is possible to manufacture a catalyst device that can be manufactured without increasing the number of manufacturing steps or complicating the mechanism, and in which the holding performance of the catalyst carrier does not change even in a high temperature environment.
Furthermore, the outer cylinder made of any one of pure titanium, a titanium alloy and a titanium compound, or an alloy containing at least one of pure titanium, a titanium alloy and a titanium compound has an advantage of a high melting point, for example, It can be installed near the internal combustion engine in the exhaust path, and can be used for a long time even in an environment exposed to high-temperature exhaust gas. The above materials have the advantage of being lightweight, such as weight reduction of the vehicle body when installed in a motorcycle or automobile, improvement of freedom in designing the vehicle body, improvement of handling and workability, etc. An advantageous effect is obtained.

Furthermore, in the above configuration, the outer cylinder (13) is an exhaust pipe made of pure titanium, a titanium alloy and a titanium compound, or an alloy containing one or more of pure titanium, a titanium alloy and a titanium compound. by being bonded to and shall constitute an exhaust passage (140) of the internal combustion engine with said exhaust pipe. In this case, an outer tube made of pure titanium, a titanium alloy and a titanium compound, or an alloy containing at least one of pure titanium, a titanium alloy and a titanium compound is similarly used as pure titanium, a titanium alloy and titanium. The exhaust path of the internal combustion engine is configured by joining to an exhaust pipe made of any one of the compounds or an alloy containing one or more of pure titanium, a titanium alloy, and a titanium compound. Since the outer cylinder and the exhaust pipe are made of the same or similar metal, they can be easily joined by welding or the like, and high joint strength can be obtained. The outer cylinder that accommodates the catalyst carrier and the mat can be used as a part of the exhaust pipe, and it is not necessary to prepare an exterior that accommodates the catalyst device itself, thereby reducing cost and weight. be able to.
Here, the exhaust pipe is an exhaust manifold, a collecting pipe, a silencer (exhaust muffler) connected to the internal combustion engine, or a pipe connecting these.

Further, in the outer cylinder (13) , the catalyst carrier (11) and the mat (12) are accommodated in a compressed state, and the catalyst carrier (11) and the outer mat of the mat (12) that are press-fitted. It has a configuration which holds the catalyst support (11) by the repulsive force acting on the cylinder (13). In this case, when the mat and the catalyst carrier are accommodated in the outer cylinder by press fitting, canning or winding, the mat and the catalyst carrier are stored in a compressed state, and the catalyst carrier and the outer cylinder are caused by the repulsive force of the compressed mat. Friction is generated between the mat and the mat, and the catalyst carrier is held at a predetermined position in the outer cylinder by this friction. In this configuration, if a material having a low linear expansion coefficient is used for the outer cylinder, the size of the outer cylinder is almost the same as that at normal temperature even in an environment exposed to high-temperature exhaust gas. It can be held in the outer cylinder by the repulsive force. Therefore, even if the exhaust gas is exposed to a high temperature, a catalyst device in which the retention performance of the catalyst carrier hardly changes from the normal temperature state can be realized.

According to the present invention, since the expansion of the outer cylinder is suppressed to a slight amount even when exposed to high-temperature exhaust gas during use of the catalyst device, the outer cylinder is interposed between the outer cylinder and the catalyst carrier. Thus, a catalyst device capable of holding the catalyst carrier in the same manner as at room temperature can be realized. And, by making the material used for the outer cylinder of this catalyst device a material whose coefficient of linear expansion is lower than that of stainless steel, it is easy to use without complicated structure, without increasing manufacturing man-hours and complicated mechanism. Is feasible. In addition, the amount of deformation due to expansion is small even when exposed to high-temperature exhaust gas during use, so that it can be manufactured without increasing the number of manufacturing steps and the complexity of the mechanism, and the catalyst carrier can be retained even in a high-temperature environment. A catalytic device whose performance does not change can be realized. In addition, since the amount of deformation of the outer cylinder accompanying a rise in temperature is kept small, there is an advantage that the allowable accuracy range is widened and the degree of freedom in design and manufacturing is increased.
Further, the outer cylinder has an advantage of a high melting point, and can be used for a long time even in an environment exposed to high-temperature exhaust gas. The above materials have the advantage of being lightweight, such as weight reduction of the vehicle body when installed in a motorcycle or automobile, improvement of freedom in designing the vehicle body, improvement of handling and workability, etc. An advantageous effect is obtained.
Furthermore, since the outer cylinder and the exhaust pipe are made of the same or similar metal, they can be easily joined by welding or the like, and a high joining strength can be obtained. In addition, the outer cylinder that houses the catalyst carrier and the mat is obtained. Can be used as a part of the exhaust pipe, and it is not necessary to prepare an exterior housing the catalyst device itself, so that the cost and weight can be reduced.
In addition, since the catalyst carrier is held at a predetermined position in the outer cylinder by the repulsive force of the mat, if a material having a low linear expansion coefficient is used for the outer cylinder, the outer cylinder Since the size is almost the same as that at room temperature, the catalyst carrier can be similarly held in the outer cylinder by the repulsive force of the mat.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram schematically illustrating an exhaust muffler 100 including a catalyst device 1 according to a first embodiment to which the present invention is applied. The exhaust muffler 100 is provided in a motorcycle and is connected to a rear end of an exhaust pipe 110 extending from an engine (not shown) of the motorcycle. It functions as a silencer.

The exhaust muffler 100 has a cylindrical main body 120 to which a single exhaust pipe 110 extending from the engine is connected, and the catalyst device 1 including the ceramic catalyst carrier 10 is supported in the cylindrical main body 120. The catalyst device 1 includes a catalyst carrier 10 that supports a catalyst, an outer cylinder 13 that houses the catalyst carrier 10, and a holding mat 12 that has a buffer function that is sandwiched between the catalyst carrier 10 and the outer cylinder 13. ing. The catalyst device 1 is configured by accommodating a catalyst carrier 10 around which a holding mat 12 is wound in an outer cylinder 13.
The cylindrical main body 120 has an internal space partitioned into a plurality of (three in this example) expansion chambers A, B, and C via a plurality (two in this example) of partition walls 131 and 132. An end 110A of the exhaust pipe 110 passes through the front end 121 of the 120 and is fixed in the expansion chamber B, and the catalyst device 1 passes through and is fixed to the first partition wall 131 closest to the end 110A of the exhaust pipe 110. Has been.

The catalyst device 1 connects the end 110A side of the exhaust pipe 110 and the expansion chamber A through a large number of pores 5 formed in the catalyst carrier 10, and the exhaust gas discharged from the end 110A The catalyst device 1 is entered from 13A, purified when passing through the catalyst carrier 10, and discharged from the end 13B.
Here, the outer diameter of the outer cylinder 13 constituting the catalyst device 1 is formed to be slightly larger than the outer diameter of the exhaust pipe 110, and the end portion 110A enters the inside of the outer cylinder 13 as shown in FIG. It is designed to be stable in the state where The end portion 13A of the outer cylinder 13 is joined to the outer surface of the exhaust pipe 110 by welding in a state where the end portion 110A is inserted into the outer cylinder 13. In the joint portion 105, the end portion 13A and the exhaust pipe 110 are directly joined.

  The first communication pipe 135 and the second communication pipe 136 are fixed to the first partition wall 131 at positions displaced from the catalyst device 1, and the first communication pipe 135 includes the expansion chamber A and the expansion chamber. The second communication pipe 136 passes through the second partition wall 132 across the expansion chamber A, and allows the expansion chamber B and the expansion chamber C to communicate with each other. A tube member 138 constituting a tail pipe is fixed to the rear end portion 122 of the cylindrical main body 120 so that the tube member 138 communicates the expansion chamber C with the space outside the exhaust muffler 100.

In the exhaust muffler 100, the exhaust gas discharged from the end 110A of the exhaust pipe 110 passes through the catalyst device 1 and flows into the expansion chamber A in the exhaust muffler 100, as indicated by an arrow in FIG. And the flow direction is reversed again to flow into the expansion chamber C through the second communication pipe 136, and the pipe member 138 constituting the tail pipe is removed. It is discharged to the outside through.
Since the cross-sectional area of the cylindrical main body 120 is formed larger than the exhaust pipe 110 inserted into the cylindrical main body 120, the pressure is reduced when the exhaust gas flows into the expansion chambers A to C. Further, since the catalyst device 1 is disposed in the cylindrical main body 120 of the exhaust muffler 100, the layout space of the catalyst device 1 is easily ensured. Further, since the catalyst device 1 is arranged substantially coaxially with the end portion 110A of the exhaust pipe 110, the exhaust gas discharged from the end portion 110A of the exhaust pipe 110 can be allowed to flow into the catalyst device 1 without changing its flow direction. it can.

FIG. 2 is an exploded perspective view showing the configuration of the catalyst device 1.
The catalyst carrier 10 is a honeycomb-like porous structure formed in a cylindrical shape and having a large number of pores 5 extending along the axial direction inside the cylindrical outer shell. A large surface area is secured inside the catalyst carrier 10 due to its porous structure, and platinum, rhodium and palladium that decompose exhaust gas components are supported as catalysts in the porous structure exposed to the respective pores 5. ing. Here, the cross-sectional shape of the catalyst carrier 10 is arbitrary, and the cross-sectional shape is not limited to a circle but may be an ellipse or a polygon.
Since porous ceramics are used as the base material of the catalyst carrier 10, a catalyst such as platinum or rhodium is easily supported. Here, as a preferable example of the material of the ceramic, various heat-resistant ceramics including cordierite, mullite, alumina, alkaline earth metal aluminate, silicon carbide, silicon nitride, or the like can be used. It is.

  The holding mat 12 is formed in a long mat shape by compressing or accumulating ceramic fibers such as alumina, and is wound around the outer surface 11 of the catalyst carrier 10. Since the convex mating portion is formed at one end of the holding mat 12 and the concave mating portion is formed at the other end, when the holding mat 12 is wound around the catalyst carrier 10, two mating portions are formed. Engagement is ensured by engaging the parts. Moreover, since the holding mat 12 is an aggregate in which fibers are intertwined, it has a relatively large elasticity. Here, the material of the holding mat 12 may be any material having heat resistance and elasticity, and a material in which fibrous metals are integrated, glass wool, or the like can also be used. Furthermore, the holding mat 12 is an aggregate in which fibers are intertwined, and the surface and the inside of the holding mat 12 are formed with countless fine gaps, so that the surface of the holding mat 12 is formed with countless fine irregularities. The surface roughness is rough and the friction coefficient is high.

On the other hand, the outer cylinder 13 is, for example, a hollow tube having a circular cross section, and both ends are open. The material constituting the outer cylinder 13 is a material having a lower linear expansion coefficient than a stainless material (for example, JIS SUS430). The linear expansion coefficient of the stainless material (linear expansion coefficient in a temperature range including normal temperature, the same applies hereinafter) is 10 × 10 ⁻⁶ / ° C. (ferritic stainless steel) to 17 × 10 ⁻⁶ / ° C. (austenitic stainless steel). SUS430, which is an example of a stainless material, has a linear expansion coefficient of 10.4 × 10 ⁻⁶ / ° C., and SUS304 has a linear expansion coefficient of 17 × 10 ⁻⁶ / ° C. The material constituting the outer cylinder 13 has a lower linear expansion coefficient than this, and preferable examples include any one of pure titanium, a titanium alloy and a titanium compound, or pure titanium, a titanium alloy and a titanium compound. The alloy containing the above is mentioned. Titanium (JIS 1-4 type pure titanium) has a linear expansion coefficient of 8.4 × 10 ⁻⁶ / ° C., and Ti-6Al-4V alloy exemplified as a titanium alloy is 8.8 × 10 ⁻⁶ / ° C. Yes, all of the other titanium alloys have a lower coefficient of linear expansion than stainless steel materials.

Here, examples of the material constituting the outer cylinder 13 include titanium alloys such as α alloys, α-β alloys, β alloys, and pure titanium (JIS type 1 to type 4), and examples of titanium alloys include titanium (Ti ), Aluminum (Al), silicon (Si), iron (Fe), copper (Cu), tin (Sn), vanadium (V), niobium (Nb), molybdenum (Mo), chromium (Cr), zirconium ( Zr) contains any one or more of other metals, may contain other inevitable impurities, and further includes oxygen (O). Specifically, Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-6Mo, Ti-1.5Al, Ti-10V-2Fe-3Al, Ti-7Al-4Mo, Ti -5Al-2.5Sn, Ti-6Al-5Zr-0.5Mo-0.2Si, Ti-5.5Al-3.5Sn-3Zr-0.3Mo-1Nb-0.3Si, Ti-8Al-1Mo-1V Ti-6Al-2Sn-4Zr-2Mo, Ti-5Al-2Sn-2Zr-4Mo-4Cr, Ti-11.5Mo-6Zr-4.5Sn, Ti-15V-3Cr-3Al-3Sn, Ti-15Mo-5Zr -3Al, Ti-15Mo-5Zr, Ti-13V-11Cr-3Al, or the like can be used. Further, a material in which fine particles such as silicon carbide (SiC), boron carbide (B ₄ C, etc.), glass, iron oxide or the like are included in the material made of pure titanium or a titanium alloy may be used.

In common, these materials have a lower linear expansion coefficient than the stainless steel material as described above. Furthermore, the materials listed above and other titanium-containing materials are lighter than stainless steel materials. SUS430 density of as an example of stainless steel material (specific gravity) whereas a 7.98 g / cm ^3, the density of titanium (JIS1～4 or pure titanium) is 4.5 g / cm ^3, as an example of a titanium alloy The Ti-6AI-4V alloy is 4.4 g / cm ³ . For this reason, the catalyst device 1 configured using the outer cylinder 13 is lightweight. When the catalyst device 1 is installed in, for example, a motorcycle or an automobile, the weight of the vehicle body is reduced, and the degree of freedom in designing the vehicle body. Advantageous effects such as improvement in handling and improvement in handling and workability can be obtained.

FIG. 3 is a cross-sectional view of the catalyst device 1.
As shown in FIG. 3, the catalyst device 1 has a configuration in which an outer surface 11 is held by an outer cylinder 13 via a holding mat 12. In the process of manufacturing the catalyst device 1, the catalyst carrier 10 and the holding mat 12 are accommodated in the outer cylinder 13, and the holding mat 12 is wound around the catalyst carrier 10, and then the outer cylinder is shaped into a cylindrical shape in advance. 13 is press-fitted. Accordingly, the holding mat 12 housed in the outer cylinder 13 is in a compressed state, and the repulsive force of the fibers constituting the holding mat 12 causes the holding mat 12 to be interposed between the catalyst carrier 10 and the holding mat 12. A pressing force acts between the outer cylinder 13 and the outer cylinder 13.
Since the catalyst carrier 10 is made of a porous ceramic material, the outer surface 11 has a high surface roughness and the holding mat 12 has a rough surface. Therefore, the catalyst carrier 10 and the holding mat 12 are held so as not to move with each other due to the frictional force. The holding mat 12 and the outer cylinder 13 are also frictionally held at predetermined positions in the outer cylinder 13 against the pressure of the exhaust gas in the direction indicated by symbol D in the figure.

Hereinafter, a method for manufacturing the catalyst device 1 will be described. The various conditions such as temperature and time in the following description are merely specific examples, and do not limit the contents of the present invention.
First, a part of one end in the axial direction of the catalyst carrier 10 formed in a cylindrical shape is put into a solution containing platinum, rhodium and palladium (or a slurry containing alumina together with these) with a predetermined length (depth). Just soak. Next, a tube connected to a pump capable of sucking up the solution is connected to the other end of the catalyst carrier 10 in which one end is immersed. This tube is connected to the other end of the catalyst carrier 10 so that suction can be performed from all the pores 5. Then, by sucking through the tube by the pump, the solution is sucked up from all the pores 5, the solution contacts the surface of each pore 5, and a catalyst that is a solute on the surface of each pore 5 Adhere to.
Thereafter, the catalyst carrier 10 is pulled up from the above solution and dried with hot air at 100 ° C. for 10 minutes, and then calcined at 450 ° C. for 1 hour to allow the catalyst carrier 10 to carry the catalyst.
After firing, the holding mat 12 is wound around the outer surface 11 of the catalyst carrier 10, and the catalyst carrier 10 is press-fitted into the outer cylinder 13 together with the holding mat 12, thereby forming the catalyst device 1.

  The solution for supporting palladium, rhodium, and platinum on the catalyst carrier 10 in the above process is obtained by dissolving a compound containing these metals in a predetermined solvent. Examples of materials used for supporting palladium include nitrates, chlorides, acetates, complex salts (such as dichlorotetraammine palladium), and the like. Examples of the material for supporting platinum include nitrates, chlorides, acetates, complex salts (such as dinitrodiammine platinum and trichlorotriammine platinum). Examples of the material for supporting rhodium on the catalyst carrier 10 include nitrates, chlorides, acetates, sulfates, complex salts (pentamminechlororhodium, hexaamminerhodium, etc.) and the like. Then, by preparing a solution of these materials and impregnating the catalyst carrier 10 with the solution, palladium, platinum, or rhodium can be supported on the catalyst carrier 10. As the solvent, water or an organic solvent can be used, but water is preferable in consideration of solubility, ease of waste liquid treatment, availability, and the like. Further, after impregnating the catalyst carrier 10 in the above solution, the catalyst carrier 10 is heated to, for example, about 250 degrees and dried, so that palladium, rhodium, and platinum are supported on the porous structure of the catalyst carrier 10, and the exhaust gas is exhausted. Nitrogen oxides, HC (hydrocarbon), CO (carbon monoxide), etc. in the gas can be decomposed and purified. Depending on the exhaust gas purification performance required, the catalyst may be configured by supporting only one or two of palladium, rhodium, and platinum on the catalyst carrier 10. In addition to palladium, rhodium, and platinum, a metal or a metal compound that functions as a catalyst (for example, cerium, iridium, zirconium, or an oxide thereof) may be supported on the catalyst carrier 10.

Further, after the holding mat 12 and the catalyst carrier 10 are press-fitted into the outer cylinder 13, it is possible to further heat the catalyst device 1 to join the holding mat 12 and the outer cylinder 13. In this case, the holding mat 12 and the inner surface of the outer cylinder 13 are heated in close contact with each other, so that the holding mat 12 and the inner surface of the outer tube 13 are bonded, bonded, or joined to the extent that a predetermined holding force is exhibited.
In the first embodiment, the outer cylinder 13 is formed in a cylindrical shape in advance. However, the present invention is not limited to this, and there is a method using canning and winding.
When the catalyst carrier 10 is accommodated by canning, the catalyst carrier 10 around which the holding mat 12 is wound is applied with divided pieces each having a shape obtained by dividing the cylinder into a plurality of pieces along the axial direction. Are joined by welding, bonding, bolting or the like to form the outer cylinder 13. In this method, when joining a plurality of divided pieces, these divided pieces are pressed so as to compress the holding mat 12. For this reason, the catalyst carrier 10 and the holding mat 12 are held at predetermined positions in the outer cylinder 13 by the repulsive force of the holding mat 12 while being accommodated in the outer cylinder 13.
Further, when the catalyst carrier 10 is accommodated by winding, the end of the plate material is wound by winding a metal plate material as the material of the outer cylinder 13 around the catalyst carrier 10 around which the holding mat 12 is wound. The cylindrical outer cylinder 13 is formed by joining together by welding, bonding, bolting, or the like. In this method, a tension that compresses the holding mat 12 is applied to the plate material in the process of winding the plate material. For this reason, the catalyst carrier 10 and the holding mat 12 are held at predetermined positions in the outer cylinder 13 by the repulsive force of the holding mat 12 while being accommodated in the outer cylinder 13.

When the catalyst device 1 configured as described above is used in an exhaust muffler 100 as shown in FIG. 1, for example, the catalyst carrier 10, Both the holding mat 12 and the outer cylinder 13 are exposed to high temperatures. The ceramics constituting the catalyst carrier 10 and the holding mat 12 have a very small linear expansion coefficient. For example, ceramic honeycomb catalyst carriers having a linear expansion coefficient of about 1.2 × 10 ⁻⁶ / ° C. are known. Yes. For this reason, when the catalyst device 1 is at a high temperature, the catalyst carrier 10 and the outer cylinder 13 expand at different rates, so that the gap between the catalyst carrier 10 and the outer cylinder 13 is widened, and the repulsion of the holding mat 12 is increased. There is a possibility that the holding force of the catalyst carrier 10 by force is weakened. However, as described above, the catalyst device 1 according to the first embodiment includes the outer cylinder 13 made of a material having a lower linear expansion coefficient than a stainless steel material (for example, JIS SUS430). The expansion of the cylinder 13 is very small, there is no possibility of generating a clearance between the catalyst carrier 10 and the holding mat 12 having a low linear expansion coefficient, and the repulsive force of the holding mat 12 is not significantly reduced. For this reason, even if the exhaust gas is exposed to a high temperature, a catalyst device in which the retention performance of the catalyst carrier 10 hardly changes from the normal temperature state can be realized. Accordingly, as a provision for the case where the holding force by the holding mat 12 is reduced, for example, it is not necessary to provide a protrusion or another member that is fixed or locked so that the catalyst carrier 10 does not move in the outer cylinder 13. Therefore, the catalyst carrier 10 and the holding mat 12 can be stably held even when exposed to the heat of the exhaust gas without complicating the structure.

  The shape of the outer cylinder 13 is a simple cylindrical shape that satisfies the requirements necessary to accommodate the catalyst carrier 10 and the holding mat 12, and does not require any other complicated shape. For this reason, the man-hour required for manufacture of the outer cylinder 13 is the same as the case where the outer cylinder 13 is manufactured, for example with stainless steel or an iron-type material. Thus, the material of the outer cylinder 13 is made of a material having a lower linear expansion coefficient than that of the stainless steel material, so that a complicated structure is not used, the manufacturing man-hours and the mechanism are not complicated, and at a high temperature. In addition, the catalyst device 1 that can stably hold the catalyst carrier 10 and the holding mat 12 can be easily realized.

In particular, as described in the first embodiment, the material of the outer cylinder 13 includes one or more of pure titanium, a titanium alloy, and a titanium compound, or pure titanium, a titanium alloy, and a titanium compound. When an alloy is used, the linear expansion coefficient of the outer cylinder 13 is significantly lower than that of a stainless steel material or the like, and the amount of deformation due to expansion when exposed to high-temperature exhaust gas during use can be extremely small. For this reason, since the holding performance of the catalyst carrier 10 hardly changes even in a high-temperature environment, the accuracy necessary for securing the holding performance of the catalyst carrier 10, that is, the range of allowable accuracy is widened. There is an advantage that the degree of freedom increases.
Furthermore, any of pure titanium, titanium alloy and titanium compound mentioned as the material of the outer cylinder 13, or an alloy containing any one or more of pure titanium, titanium alloy and titanium compound has an advantage that the melting point is high. For example, there is no problem even if it is installed at a position close to the internal combustion engine in the exhaust path, and it can be used for a long time even in an environment exposed to high-temperature exhaust gas. The above materials have the advantage of being lightweight, such as weight reduction of the vehicle body when installed in a motorcycle or automobile, improvement of freedom in designing the vehicle body, improvement of handling and workability, etc. An advantageous effect is obtained.

[Second Embodiment]
FIG. 4 is a cross-sectional view showing an exhaust pipe structure 140 according to a second embodiment to which the present invention is applied.
In the second embodiment, parts that are configured in the same manner as in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.
An exhaust pipe structure 140 shown in FIG. 4 has a titanium exhaust pipe 50 joined to the engine (not shown) side of the catalyst device 1 and a titanium exhaust pipe 55 joined to the exhaust muffler (not shown) side of the catalyst device 1. Configured. The exhaust pipe structure 140 is a pipe line that forms a part of an exhaust path that connects the exhaust port of the engine and the exhaust muffler. Specifically, the exhaust manifold structure, the collecting pipe, or these and the engine or the exhaust muffler are connected to each other. It is a connecting pipe. With respect to the flow of the exhaust gas indicated by the symbol D, the titanium exhaust pipe 50 is located on the upstream side of the catalyst device 1, and the titanium exhaust pipe 55 is located on the downstream side of the catalyst device 1.

The titanium exhaust pipe 50 is constituted by a hollow pipe having a diameter smaller than that of the outer cylinder 13, and a tapered portion 51 having a gradually increasing diameter is formed at the end of the titanium exhaust pipe 50. The cylinder 13 is joined. The titanium exhaust pipe 55 is a hollow pipe having the same diameter as the outer cylinder 13.
The titanium exhaust pipe 50 and the titanium exhaust pipe 55 are both made of the same titanium-based material as the outer cylinder 13.

That is, in the second embodiment, the outer cylinder 13, the titanium exhaust pipe 50, and the titanium exhaust pipe 55 are all made of titanium alloy such as α alloy, α-β alloy, β alloy or pure titanium (JIS). In addition to titanium (Ti), aluminum (Al), silicon (Si), iron (Fe), copper (Cu), tin (Sn), vanadium (V), It contains any one or more of other metals such as niobium (Nb), molybdenum (Mo), chromium (Cr), zirconium (Zr), etc., may contain other inevitable impurities, and oxygen ( And the like containing O). Specifically, Ti-6Al-4V, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-6Mo, Ti-1.5Al, Ti-10V-2Fe-3Al, Ti-7Al-4Mo, Ti -5Al-2.5Sn, Ti-6Al-5Zr-0.5Mo-0.2Si, Ti-5.5Al-3.5Sn-3Zr-0.3Mo-1Nb-0.3Si, Ti-8Al-1Mo-1V Ti-6Al-2Sn-4Zr-2Mo, Ti-5Al-2Sn-2Zr-4Mo-4Cr, Ti-11.5Mo-6Zr-4.5Sn, Ti-15V-3Cr-3Al-3Sn, Ti-15Mo-5Zr -3Al, Ti-15Mo-5Zr, Ti-13V-11Cr-3Al, or the like can be used. Alternatively, a material in which fine particles such as silicon carbide (SiC), boron carbide (B ₄ C, etc.), glass, iron oxide or the like are included in the material made of pure titanium or a titanium alloy may be used.
The outer cylinder 13 and the titanium exhaust pipes 50 and 55 are preferably all made of the same material in consideration of ease of welding, ease of material procurement, manufacturing cost, and the like. A structure in which the exhaust pipes 50 and 55 are not made of the same material is allowed, and the outer cylinder 13 and the titanium exhaust pipes 50 and 55 may be made of different materials as long as they are any of the materials containing titanium described above. .

Thus, the outer cylinder 13 and the titanium exhaust pipes 50 and 55 are both pure titanium, a titanium alloy and a titanium compound, or an alloy containing one or more of pure titanium, a titanium alloy and a titanium compound. Therefore, the titanium exhaust pipe 50 and the outer cylinder 13 and the outer cylinder 13 and the titanium exhaust pipe 55 can be easily and reliably joined by welding, for example.
That is, as shown in FIG. 4, the tip of the tapered portion 51 and the end portion 13 </ b> A of the outer cylinder 13 have the same diameter. Joined by butt welding. Further, the end 13B of the outer cylinder 13 and the tip of the titanium exhaust pipe 55 have the same diameter, and are similarly joined by butt welding. Since welding of metal materials including titanium has good compatibility between materials, it can be easily joined with sufficient strength.

  In the exhaust pipe structure 140 according to the second embodiment, in addition to the effects described in the first embodiment, the outer cylinder 13 for accommodating the catalyst carrier 10 and the holding mat 12 in the catalyst device 1 is provided. There is an advantage that it can be used as a part of the exhaust pipe structure 140. Thereby, the exterior etc. for accommodating the catalyst apparatus 1 are unnecessary, and cost reduction and weight reduction can be achieved. Further, the titanium exhaust pipes 50 and 55 joined to the outer cylinder 13 are either pure titanium, a titanium alloy and a titanium compound, or pure titanium, a titanium alloy and a titanium compound, like the outer cylinder 13. Since it is composed of an alloy containing one or more, the same type or similar types of metals are joined to each other, and can be easily joined by welding or the like, and high joint strength can be obtained.

[Third Embodiment]
FIG. 5 is a cross-sectional view showing an exhaust pipe structure 140 according to a second embodiment to which the present invention is applied.
Note that in the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.
An exhaust pipe structure 150 shown in FIG. 5 has a stainless exhaust pipe 60 joined to the engine (not shown) side of the catalyst device 2 and a stainless exhaust pipe 65 joined to the exhaust muffler (not shown) side of the catalyst device 2. Configured.
The exhaust pipe structure 150 is a pipe line that constitutes a part of an exhaust path that connects the exhaust port of the engine and the exhaust muffler. Specifically, the exhaust pipe structure 150 connects the exhaust manifold, the collecting pipe, or these with the engine or the exhaust muffler. It is a connecting pipe. The exhaust pipe 60 made of stainless steel is located on the upstream side of the catalyst device 2 and the exhaust pipe 65 made of stainless steel is located on the downstream side of the catalyst device 1 with respect to the flow of the exhaust gas indicated by the symbol D.

  The catalyst device 2 includes the outer tube 14 in place of the outer tube 13 in the catalyst device 1 described above. The outer cylinder 14 is a cylindrical hollow tube made of the same material as the outer cylinder 13. The difference from the outer cylinder 13 is that the upstream end portion 14A and the downstream end portion 14B with respect to the exhaust direction D are processed to join the stainless steel exhaust pipes 60 and 65, respectively. There is in point.

  The stainless steel exhaust pipes 60 and 65 are both hollow pipes made of a stainless material (SUS430, SUS304, etc.). In the joint portion between the stainless steel exhaust pipe 60 and the outer cylinder 14 and the joint portion between the outer cylinder 14 and the stainless steel exhaust pipe 65, the stainless steel exhaust pipes 60 and 65 are both slightly smaller in diameter than the outer cylinder 14. And enters the outer cylinder 14. In this state, the outer cylinder 14 and the stainless steel exhaust pipe 60 and the outer cylinder 14 and the stainless steel exhaust pipe 65 are joined by welding the joining pieces 61 and 66.

6 is an enlarged view showing the structure of the joint portion in the exhaust pipe structure 140, FIG. 6A shows the joint portion between the stainless steel exhaust pipe 60 and the outer cylinder 14, and FIG. 6B shows the outer cylinder 14 and the stainless steel exhaust pipe. A junction with 65 is shown.
As shown in FIG. 6A, a hole 14 </ b> C is formed in an end portion 14 </ b> A that is an open end on the upstream side of the outer cylinder 14. The holes 14 </ b> C are holes that penetrate the outer cylinder 14, and a plurality of holes 14 </ b> C are formed at predetermined intervals along the circumferential direction of the opening edge of the outer cylinder 14.
The end portion 60A of the stainless steel exhaust pipe 60 penetrates into the end portion 14A farther than the hole 14C, and in this state, the joining piece 61 is welded to the end portion 60A. The joining piece 61 is a metal piece having a shape that comes into contact with the end portion 60 </ b> A from the outside of the outer cylinder 14 through the hole 14 </ b> C, and is made of the same stainless steel material as the stainless steel exhaust pipe 60.

  The end 60A and the joining piece 61 are welded by projection welding. That is, electricity is applied between the joining piece 61 and the stainless steel exhaust pipe 60 in a state where the joining piece 61 is inserted into the hole 14 </ b> C, and the joining portion 61 is joined by heat generation at the contact portion. By this method, the joining piece 61 is welded to the end portion 60A through all the holes 14C provided in the end portion 14A. Here, although the some joining piece 61 will be joined, these some joining piece 61 may be connected mutually, and each may be an independent small piece.

On the other hand, as shown in FIG. 6B, a hole 14 </ b> D is formed in an end portion 14 </ b> B that is an open end on the downstream side of the outer cylinder 14. The holes 14 </ b> D are holes that penetrate the outer cylinder 14, and a plurality of holes 14 </ b> D are formed at predetermined intervals along the circumferential direction of the opening edge of the outer cylinder 14.
The end portion 65A of the stainless steel exhaust pipe 65 enters the end portion 14B farther than the hole 14D. In this state, the joining piece 66 is welded to the end portion 65A. The joining piece 66 is a metal piece having a shape that comes into contact with the end portion 65 </ b> A from the outside of the outer cylinder 14 through the hole 14 </ b> D, and is made of the same stainless steel material as the stainless steel exhaust pipe 65.

  The end portion 65A and the joining piece 66 are welded by projection welding. That is, electricity is applied between the joining piece 66 and the stainless steel exhaust pipe 65 in a state where the joining piece 66 is inserted into the hole 14D, and the joining part 66 is joined by heat generation at the contact portion. By this method, the joining piece 66 is welded to the end portion 65A through all the holes 14D provided in the end portion 14B. Here, although a plurality of joining pieces 66 are joined, the plurality of joining pieces 66 may be connected or may be independent small pieces.

  In the exhaust pipe structure 150, it is necessary to join the outer cylinder 14 made of a material containing titanium and the stainless steel exhaust pipes 60 and 65. In joining these dissimilar metals, holes 14C and 14D are provided in the end portions 14A and 14B of the outer cylinder 14, respectively, and the joining pieces 61 and 66 and the stainless steel exhaust pipes 60 and 65 are connected using the holes 14C and 14D. Join. According to this method, the outer cylinder 14 and the stainless steel exhaust pipes 60 and 65 can be easily joined with sufficient strength by welding the same kind of metal.

Similar to the catalyst device 1 described above, the catalyst device 2 is configured by accommodating the catalyst carrier 10 and the holding mat 12 in an outer cylinder 14 made of a material having a lower linear expansion coefficient than the stainless material. For this reason, advantages as described in the first and second embodiments described above can be obtained.
In addition, the exhaust pipe structure 150 can be realized at low cost by using cheaper stainless steel exhaust pipes 60 and 65. Also in the exhaust pipe structure 150, the advantage as described in the second embodiment, that is, the outer cylinder 14 for accommodating the catalyst carrier 10 and the holding mat 12 can be used as a part of the exhaust pipe structure 150. Further, there is no need for an exterior for housing the catalyst device 2, and there is an advantage that cost reduction and weight reduction can be achieved.
Further, the outer cylinder 14 and the stainless steel exhaust pipes 60 and 65 to be joined with different metals are formed by forming holes 14C and 14D in the end portions 14A and 14B of the outer cylinder 14 and joining pieces 61 and 66 from the outside. Can be easily and reliably performed by the method of applying projection welding.

In addition, the said embodiment shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said embodiment.
For example, in the above embodiment, the outer cylinders 13 and 14 have been described as being cylindrical, but the present invention is not limited to this, and a hollow tube may have an elliptical or polygonal cross-sectional shape. Good. Moreover, although the said embodiment demonstrated platinum, rhodium, and palladium as what carry | supports on the catalyst support | carrier 10, you may carry | support other catalyst substances, such as iridium and a cerium oxide. Further, the holding mat 12 is not limited to covering the entire outer surface 11 of the catalyst carrier 10, and a part of the outer surface 11 may be exposed without being covered by the holding mat 12. Of course, other detailed configurations can be arbitrarily changed.

It is a figure showing typically an exhaust muffler provided with a catalyst device concerning a 1st embodiment of the present invention. It is the disassembled perspective view which showed the structure of the catalyst apparatus. It is sectional drawing of a catalyst apparatus. It is sectional drawing which shows the exhaust pipe structure provided with the catalyst apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the exhaust pipe structure provided with the catalyst apparatus which concerns on the 3rd Embodiment of this invention. It is an enlarged view which shows the structure of the junction part in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Catalytic device 5 Pore 10 Catalyst carrier 11 Outer surface 12 Holding mat 13, 14 Outer cylinder 50, 55 Titanium exhaust pipe 60, 65 Stainless steel exhaust pipe 61, 66 Joint piece 100 Exhaust muffler 105 Joint section 140, 150 Exhaust pipe structure

Claims (2)

A ceramic catalyst carrier (11) carrying a catalyst for purifying exhaust gas of an internal combustion engine;
An outer cylinder (13) for accommodating the catalyst carrier (11) ;
A mat (12) interposed between the outer cylinder (13) and the catalyst carrier (11) ,
The outer cylinder (13) is low by SUS430 stainless steel remote sensing expansion coefficient, pure titanium, or titanium alloys and titanium compounds, or pure titanium, any alloy containing one or more titanium alloys and titanium compounds It is configured as a material,
The outer cylinder (13) is joined to an upstream exhaust pipe (50) located upstream in the flow direction of the exhaust gas, so that the exhaust path of the internal combustion engine ( 140),
The outer cylinder (13) has a cylindrical shape with the same diameter from the end portion (13A) on the inlet side to the end portion (13B) on the outlet side, and is arranged in the longitudinal direction of the catalyst carrier (11) and the mat (12). The size is smaller than the size of the outer cylinder (13) in the longitudinal direction, and the catalyst carrier (11) and the mat (12) are disposed at positions retracted from both ends of the outer cylinder (13). Retained,
The upstream exhaust pipe (50) is made of pure titanium, a titanium alloy and a titanium compound, or an alloy containing one or more of pure titanium, a titanium alloy and a titanium compound,
In the outer cylinder (13), the catalyst carrier (11) and the mat (12) are accommodated in a compressed state, and the catalyst carrier (11) and the outer cylinder ( A catalyst device characterized in that the catalyst carrier (11) is held by a repulsive force acting on 13) . The outer cylinder (13) is joined to the upstream exhaust pipe (50) and the downstream exhaust pipe (55) located on the downstream side, so that the upstream exhaust pipe (50) and the downstream exhaust pipe are connected. Constituting an exhaust path (140) of the internal combustion engine together with the pipe (55);
  The downstream exhaust pipe (55) is a straight pipe having the same diameter as the downstream end (13B) of the outer cylinder (13) and is butt-joined to the end (13B),
  The downstream exhaust pipe (55) is made of pure titanium, a titanium alloy and a titanium compound, or an alloy containing one or more of pure titanium, a titanium alloy and a titanium compound. Item 4. The catalyst device according to Item 1.

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