JP3071185U - Exhaust system members for internal combustion engines - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To stabilize and improve exhaust gas purification performance, improve cutting and discharging by shock and vibration of sound absorbing fiber, prevent deterioration of sound absorbing performance, and improve durability and weight of exhaust system members. SOLUTION: An exhaust system member for an internal combustion engine as an exhaust gas purifying catalyst carrier is a metal fiber sintered body 1 formed in a pipe shape or a sheet shape. An exhaust system member for an internal combustion engine as a sound absorbing material is a sintered body of a metal fiber. In an exhaust system member for an internal combustion engine having a sound absorbing portion composed of a perforated pipe and a glass fiber outside the perforated pipe, a sintered body of metal fibers is arranged between the perforated pipe and the glass fiber. The sintered body of the metal fiber is an iron-based alloy.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an exhaust system member installed in an exhaust system of an internal combustion engine and used as a catalyst carrier or a sound absorbing material.

[0002]

[Prior art]

 The functions of the exhaust system of an internal combustion engine are required to purify exhaust gas, absorb sound, prevent reduction in exhaust gas outflow resistance, and reduce the weight of components. For purification of exhaust gas, a catalyst body such as cordierite or other ceramic honeycomb or glass wool, a heat-resistant stainless steel perforated pipe, or a metal honeycomb or other catalyst carrier carrying a noble metal catalyst substance is generally used. . When high mechanical strength is required against vibration and impact, a metallic material is appropriate among these catalyst supports.

[0003] However, since the catalyst support of the metal honeycomb can increase the surface area, the catalyst characteristics can be improved by enlarging the contact area with the exhaust gas. However, since the exhaust gas passes through many honeycomb-shaped small holes, the resistance is low. As the size of the engine increases, the reduction in output becomes a problem for small internal combustion engines. In addition, when the porous pipe is used as a catalyst carrier, the surface area in contact with the exhaust gas is small, and the increase in the surface area due to the increase in the number of holes is small.

As sound absorbing means, a glass fiber wound around a perimeter of a perforated pipe, a sheet-shaped metal fiber formed by needle punching a mesh-shaped or non-woven metal fiber, and a glass fiber overlapped with the glass fiber Is installed in an exhaust passage as a sound absorbing material. Exhaust system members have an environmental problem in that glass fibers are cut by high exhaust temperature, wind pressure and vibration, and are discharged through porous pipes or mesh-shaped metal fibers. Further, since the metal fibers formed into a sheet by needle punching are in an engaged state due to mechanical partial deformation, there is no strong bonding between the fibers, and the bonding state is a slight deformation of the fibers under the exhaust conditions. Deterioration and long-term use cause the same problems as perforated pipes and net-shaped metal fibers.

[0005]

[Problems to be solved by the invention]

 For this reason, the present invention is intended to stabilize and improve the exhaust gas purification performance by increasing the contact area of the catalyst carrier with the exhaust gas without increasing the outflow resistance of the exhaust gas. The third is to improve the cutting and discharging by shock and vibration, cut the glass fiber in the sound absorbing part, prevent the sound absorbing performance from deteriorating due to scattering, improve the environment, and reduce the durability and weight of the exhaust system members of the internal combustion engine. It is intended to be realized.

[0006]

[Means for Solving the Problems]

 The means of the present invention is characterized in that an exhaust system member for an internal combustion engine used as an exhaust gas purifying catalyst carrier is a sintered body of a metal fiber formed in a pipe shape or a sheet shape (claim 1). In this means, since the sintered body of the metal fiber is used, the exhaust resistance is smaller than that of the conventional metal honeycomb, and the contact area with the exhaust gas can be increased without increasing the outflow resistance of the exhaust gas. Therefore, the purification performance of the exhaust gas can be stabilized and improved.

[0007] The means of the present invention is characterized in that the exhaust system member for the internal combustion engine used as the sound absorbing material is a sintered body of metal fiber (claim 2). This method does not have the problems of cutting, scattering, and short life like glass fiber compared to the conventional glass fiber, and also has the advantage of using conventional needle-punched metal fiber. The bond strength between metal fibers is large, and deterioration due to long-term use is small. Therefore, it is possible to provide an exhaust system member for an internal combustion engine as a durable sound absorbing material.

The present invention also provides an exhaust system member for an internal combustion engine having a sound absorbing portion composed of a perforated pipe and a glass fiber outside the perforated pipe, wherein a metal fiber is fired between the perforated pipe and the glass fiber. The present invention is characterized in that a union is arranged (claim 3). In this method, compared to the conventional glass fiber held directly in contact with the outside of the perforated pipe, the cutting of the glass fiber cut by the exhaust resistance or vibration due to the interposition of the sintered body of the metal fiber. It is possible to provide an exhaust system member for an internal combustion engine that has a significantly reduced amount, does not fall off and scatter, and has excellent durability.

In the above means (claim 1, claim 2, or claim 3), the metal fiber sintered body is formed by heat-treating and sintering a metal fiber having a shape other than a net shape. (Claim 4). Since the mesh-shaped metal fibers are fibers having a planar connection, when they are laminated to form a sheet-shaped sintered body, the pore diameter cannot be reduced to a certain size or less, and the fibers are closed. The pores are so close that they are not suitable as a catalyst carrier or sound absorbing material. Therefore, it is preferable to use a metal fiber sintered body obtained by sintering metal fibers other than the mesh shape, for example, short fibers, long fibers, or non-woven metal fibers, in which the pores are unlikely to be closed.

In the above means (claim 1, claim 2, or claim 3), it is preferable that the sintered body of the metal fiber is made of an iron-based alloy (claim 5). In this configuration, since the sintered body of the metal fibers is made of an iron-based alloy, the heat resistance can be satisfied with respect to the temperature at the position where the exhaust gas purifying catalyst carrier is provided and the position where the sound absorbing material is provided. High strength can be obtained.

In the above means (claim 1, claim 2, or claim 3), it is preferable that the thickness of the sintered body of the metal fiber is 0.05 mm or more (claim 6). In this configuration, if the thickness of the sintered body of the metal fiber is smaller than 0.05 mm, the strength is low due to the small number of contact points of the metal fiber, and practically not practical. By making it 05 mm or more, it becomes practical.

[0012]

[Embodiment of the invention]

 The first to fourth embodiments of the present invention will be described with reference to the drawings. In the first embodiment, as shown in FIGS. 1A and 1B, an exhaust gas purifying catalyst carrier of an exhaust system member of an internal combustion engine is constituted by a cylindrical metal fiber sintered body 1. This metal fiber sintered body 1 is obtained by filling a metal mold into a mold for forming a cylinder and molding by pressurizing, or filling a graphite case for forming a cylinder with the metal fiber under vacuum or inert atmosphere conditions. And heat-treated for sintering. In the figure, reference numeral 2 denotes a punching hole, which is a porous body.

In the second embodiment, the catalyst carrier in the exhaust system member of the internal combustion engine is formed of a flat sheet-shaped sintered metal fiber 3. That is, as shown in FIGS. 2A and 2B, a metal fiber uniformly dispersed in a plane is heat-treated and sintered as in the first embodiment. 4 (a) and (b) are punched holes, which are made of a porous material.

In the first and second embodiments, when it is necessary to use hardly sinterable metal fibers or a dense sintered body, heat molding may be used. In this case, the porosity of the sintered body can be changed depending on conditions such as a molding pressure and a heat treatment temperature. In each of the drawings, the sintered body is punched to form a porous body having holes 2 and 4, but the punching may be omitted. The metal fiber sintered bodies 1 and 3 of the catalyst carrier are applied stepwise or simultaneously with a solution in which an alumina film is formed by heat treatment or a catalyst solution by applying or dipping, and then dried and fired to solidify the catalyst particles on the surface. To the catalyst carrying state.

Using the same metal fiber and the same mold as the metal fiber sintered body 1 formed as a catalyst carrier, sinters having different porosity are formed stepwise from 0% to 90%, and each sintered body is formed. Table 1 shows the results obtained by measuring the surface area with respect to the porosity by the body by the BET method.

[0016]

[Table 1]

From the results shown in Table 1, it can be seen that the surface area increases in proportion to the porosity for the same size and shape, although the shape may slightly change depending on the form and filling method of the metal fiber. Due to the increase in the surface area of the sintered body, the contact area between the exhaust gas and the catalyst carrier increases, and the resistance of the exhaust gas does not increase unlike the conventional metal honeycomb catalyst carrier. Therefore, it is effective as an exhaust gas purifying catalyst for a relatively small internal combustion engine. Although the fibers of the sintered body are firmly adhered to each other by heat treatment, the strength decreases when the porosity becomes about 80% or more. However, if the fibers are fixed with a perforated pipe or a frame plate, they can be used.

Since the sheet-shaped sintered body 2 of the catalyst carrier is easy to shape, it is brazed or mechanically joined along the inside of the exhaust pipe having a complicated shape, for example, using screws or metal fittings. It is possible to use it. Thus, by arranging it near the exhaust hole of the internal combustion engine or at a position outside the bend of the inner surface of the exhaust pipe where the bend angle of the exhaust pipe 5 is large as schematically shown in FIG. A high catalytic effect can be obtained due to contact. The arrows in the figure indicate the direction in which the exhaust gas flows.

As the form of the metal fibers used for the catalyst carrier, short fibers, long fibers, and nonwoven fabrics can be used. The use of mesh-shaped metal fibers is not preferred because the pore size of the sintered body cannot be reduced to a certain degree or less, or the laminate has a two-dimensional shape. The material of the metal fibers of the metal fiber sintered bodies 1 and 2 only needs to be able to withstand the temperature of the respective arrangement portions, and from the practicality, it is preferable to use metal fibers of an iron-based alloy.

The third embodiment is a sound-absorbing material used for a sound-absorbing part of an exhaust system of an internal combustion engine. As shown in FIG. 3, the sound-absorbing material includes a cylindrical metal fiber sintered body 11 inside an exterior pipe 10. The sound absorbing material is arranged, and a number of small holes 12 perforated pipes 13 are arranged and fixed inside the sound absorbing material. In addition, the configuration of this type of conventional sound absorbing portion is generally a glass fiber layer instead of the metal fiber sintered body 11 of the sound absorbing material shown in FIG. I do.

The fourth embodiment is a sound absorbing material and holding material used for a sound absorbing part of an exhaust system of an internal combustion engine. As shown in FIG. 4, a glass fiber layer 14 is used as a main sound absorbing material, A metal fiber sintered body sheet 16 is arranged between a perforated pipe 15 having a large number of small holes 18 and a glass fiber layer 14 of a sound absorbing material. In the figure, reference numeral 17 denotes an exterior pipe.

For the third and fourth embodiments and the comparative example, a test was conducted in which hot air at 600 ° C. was flowed through the sound absorbing portion at 400,000 cc / min for 100 hours, and then disassembled to observe the inside. I did it. In the comparative example, the weight was reduced by about 13% with respect to the glass fiber of the sound absorbing material before the test, and it was confirmed that the glass fiber was cut during decomposition. In the third embodiment, the metal fiber sintered body 11 was discolored, but no drop due to cutting of the metal fiber was confirmed. In the fourth embodiment, although the glass fibers of the glass fiber layer 14 of the sound absorbing material fell during the decomposition, it was confirmed that the weight of the glass fibers 14 was not reduced and the glass fibers were not scattered.

The forms of the metal fibers of the third and fourth embodiments are short fibers, long fibers, and non-woven fabrics for the same reason as in the case of the catalyst carrier in the first and second embodiments. Or a sintered body thereof can be used. Further, the material of the metal fiber only needs to be able to clear the heat-resistant temperature of each disposition portion, and it is preferable to use a metal fiber of an iron-based alloy for practical use. Further, the sintered sheet of metal fiber used in the fourth embodiment is preferably thin for weight reduction, but the practical thickness is 0.05 mm or more. When the thickness is 0.05 mm or less, the strength is not reduced due to the decrease in the number of contact points of the metal fibers, and the effect of preventing the cut glass fibers from scattering due to the expansion of the pore diameter cannot be obtained.

[0024]

[Effect of the invention]

 ADVANTAGE OF THE INVENTION The invention of claim 1 has an effect that an exhaust system member for an internal combustion engine can be provided as a catalyst carrier capable of stabilizing and improving exhaust gas purification performance. The invention according to claim 2 has an effect that an exhaust system member for an internal combustion engine as a durable sound absorbing material can be provided. The invention according to the third aspect has an effect that an exhaust system member for an internal combustion engine having excellent durability can be provided even with a configuration using glass fiber. The invention according to claim 4 has an effect that an exhaust system member for an internal combustion engine can be provided as a better catalyst carrier or sound absorbing material. The invention described in claim 5 has an effect of providing a highly practical exhaust system member for an internal combustion engine. The invention according to claim 6 has an effect that a practical exhaust system member for an internal combustion engine can be provided.

[Brief description of the drawings]

1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is a schematic front view, and FIG. 1B is a schematic plan view.

FIGS. 2A and 2B show a second embodiment of the present invention, wherein FIG. 2A is a schematic front view, FIG. 2B is a schematic plan view, and FIG. is there.

FIG. 3 is a cross-sectional view of an exhaust pipe according to a third embodiment of the present invention.

FIG. 4 is a sectional view of an exhaust pipe showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1, 3 metal fiber sintered body 2, 4 punching hole 5 exterior pipe 10 exterior pipe 11 metal fiber sintered body 12 small hole 13 perforated pipe 14 glass fiber layer 15 perforated pipe 16 metal fiber sintered body 17 exterior pipe 18 small hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihiko Hama 3-12 Kanbei-cho, Otsu-ku, Himeji-shi, Hyogo Pref. No. 12 Inside the Himeji Higashi Factory (72) Inventor Seiji Okada 3-12 Kanbei-cho, Otsu-ku, Himeji City, Hyogo Prefecture Inside the Himeji Higashi Factory (72) Inventor Jiro Takegawa Fujishimacho Brahma-ten Inside 110 Takekawa Engineering Co., Ltd. at 110

Claims (6)

[Utility model registration claims] 1. An exhaust system member for an internal combustion engine, wherein the exhaust system member for an internal combustion engine used as an exhaust gas purifying catalyst carrier is a sintered body of a metal fiber formed in a pipe or sheet shape. 2. An exhaust system member for an internal combustion engine, wherein the exhaust system member for an internal combustion engine used as a sound absorbing material is a sintered body of a metal fiber. 3. An exhaust system member for an internal combustion engine having a sound absorbing portion composed of a perforated pipe and a glass fiber outside the perforated pipe, wherein a sintered body of metal fibers is arranged between the perforated pipe and the glass fiber. An exhaust system member for an internal combustion engine, comprising: 4. The exhaust system member for an internal combustion engine according to claim 1, wherein the metal fiber sintered body is formed by heat-treating a metal fiber having a shape other than a mesh shape and sintering the metal fiber. An exhaust system member for an internal combustion engine, characterized in that: 5. The exhaust system member for an internal combustion engine according to claim 1, wherein the sintered body of the metal fibers is an iron-based alloy. Exhaust system members. 6. The exhaust member for an internal combustion engine according to claim 1, wherein a thickness of the sintered body of the metal fiber is 0.05 mm or more. Exhaust system members for internal combustion engines.