JPH063445U - Catalytic converter - Google Patents

Abstract

(57) [Abstract] [Purpose] Improve the degree of freedom of installation location by forming a small size and small cross-sectional area. [Structure] A catalyst carrier 11 is supported in a tubular casing 10. The catalyst carrier 11 is made by lightly compressing a large number of ferritic stainless steel fibers. A large number of fine whiskers are formed on the surface of each fiber, and the catalyst is supported on the surface of each fiber by the large number of whiskers.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The catalytic converter according to the present invention is provided in the middle of the exhaust system of an automobile to detoxify harmful components contained in the exhaust discharged from the engine.

[0002]

[Prior art]

 In order to detoxify harmful components (NOx, CO, HC, etc.) contained in the exhaust gas emitted from the automobile engine, the exhaust system exhausts the exhaust gas to the atmosphere. It is widely practiced to provide a catalytic converter.

Conventionally, a catalytic converter having a structure as shown in FIG. 2 has been widely used. This catalytic converter accommodates a honeycomb catalyst carrier 2 in a casing 1 via buffer materials 3 and 4 in a buffer manner, and does not provide a space between the inner peripheral surface 1a of the casing 1 and the outer peripheral surface 2a of the honeycomb catalyst carrier 2. A breathable mat 5 is provided to prevent exhaust gas from passing through the honeycomb catalyst carrier 2 and bypassing between the two peripheral surfaces 1a, 2a.

For example, a casing 1 formed by press-forming a metal plate and combining a pair of halves in the middle has an exhaust inlet 6 and an exhaust outlet 7 formed at the front and rear ends, and an intermediate portion in the middle. It is configured by connecting the formed cylindrical holding portion 8 with the step portions 9 and 9. The inner diameter of the holding portion 8 is made sufficiently larger than the inner diameters of the exhaust inlet 6 and the exhaust outlet 7.

Among the cushioning materials 3 and 4 for cushioningly supporting the honeycomb catalyst carrier 2 in the casing 1 as described above, the cushioning material 3 wound around the outer peripheral surface of the catalyst carrier 2 is made of stainless steel. The honeycomb catalyst carrier is formed by corrugating a wire mesh formed by braiding filaments, and is elastically compressed between the inner peripheral surface 1a of the casing 1 and the outer peripheral surface 2a of the honeycomb catalyst carrier 2. Buffer 2 is supported.

The cushioning materials 4 and 4 provided between the stepped portions 9 and 9 of the casing 1 and the corner portions of the honeycomb catalyst carrier 2 are formed by knitting a stainless steel wire mesh into a tubular shape and press-molding. It prevents the corner portion of the brittle honeycomb catalyst carrier 2 from colliding with and damaging the inner surface of the casing 1.

Further, the air-impermeable mat 5 contains a substance having a heat-expanding property such as expansive mica as disclosed in, for example, Japanese Patent Laid-Open No. 51-69507. The space between the outer peripheral surface 2a of the honeycomb catalyst carrier 2 and the inner peripheral surface 1a of the holding portion 8 of the casing 1 is filled to maintain airtightness between the both peripheral surfaces 2a, 1a.

When the catalytic converter configured as described above is used, exhaust gas containing harmful substances is sent from the exhaust gas inlet 6 into the casing 1, and the exhaust gas is passed through the honeycomb catalyst carrier 2 before being discharged to the exhaust gas outlet. Discharge from 7. While passing through the honeycomb catalyst carrier 2, the harmful components in the exhaust gas are oxidized and reduced by the action of the catalyst adhering to the surface of the honeycomb catalyst carrier 2, and converted into harmless substances.

[0009]

[Problems to be solved by the device]

 The catalytic converter of the present invention improves the degree of freedom of the mounting position of the catalytic converter by making it compact and having a small cross-sectional area.

In the case of the conventional structure, the cross-sectional area cannot be reduced because the honeycomb catalyst carrier 2 needs to be buffered inside the casing 1. Further, since the honeycomb catalyst carrier 2 which cannot be bent is incorporated, the catalyst converter can be mounted only on the straight line portion having a certain length. Therefore, the mounting position of the catalytic converter is limited, and for example, a small catalytic converter that can be installed in the engine room has not been realized.

On the other hand, in recent years, from the standpoint of stricter environmental protection, it has been considered to perform exhaust gas purification with a plurality of catalyst converters. For example, a small exhaust gas purifier that can be installed immediately after the exhaust manifold. Realization of (pre-converter) is desired.

[0012]

[Means for Solving the Problems]

 As shown in FIG. 1, the catalytic converter of the present invention comprises a tubular casing 10 and a catalyst carrier 11 supported in the casing 10. Unlike the honeycomb catalyst carrier in the conventional structure, this catalyst carrier 11 is formed into a metal scrubber shape by lightly compressing a large number of ferritic stainless steel fibers containing aluminum and chromium. Therefore, there is a clearance space through which exhaust gas can freely flow. As the ferritic stainless steel, for example, ferritic stainless steel containing aluminum (for example, Fe-20Cr-5Al) as described in JP-A-57-71898 can be preferably used.

As described in the above publication, a large number of fine whiskers are formed on the surface of a large number of fibers constituting the catalyst carrier 11 by heat-treating the ferritic stainless steel. A large number of whiskers carry the catalyst on the surface of each fiber.

In order to prevent the catalyst carrier 11 from shifting in the casing 10 as described above, a part of the casing 10 is provided on the upstream side and the downstream side of the catalyst carrier 10 with a porous material such as a wire mesh. The plates 12, 12 may be fixed. Alternatively, the entire catalyst carrier 11 may be wrapped in a heat-resistant mesh, and the catalyst carrier 11 may be mounted together with this mesh in the casing 10. In this case, if the mounting portion of the catalyst carrier 11 in a part of the casing 10 has a large diameter and the downstream side of this mounting portion has a small diameter, the catalyst carrier 11 is moved downward due to the exhaust pressure. It will not be pushed.

[0015]

[Action]

 When the catalytic converter of the present invention constructed as described above is used, the exhaust gas sent into the casing 10 is harmless because it comes into contact with the catalyst carried on the surface of many fibers constituting the catalyst carrier 11. After being subjected to the chemical treatment, it is discharged from the rear end portion of the casing 10 to the outside of the casing 10.

Particularly, in the case of the catalytic converter of the present invention, since the catalyst carrier 11 is formed in the shape of a metal scrubber by compressing metal fibers, it is particularly necessary to buffer the catalyst carrier 11 in the casing 10. No need to adopt structure. Further, since the catalyst carrier 11 can be bent, it is possible to configure a catalytic converter by using an exhaust manifold, a part of an exhaust pipe, or the like as a casing.

[0017]

[Effect of device]

 The catalytic converter of the present invention is constructed and operates as described above, but since it can be formed in a small and small cutting area and can be formed in a bent shape, it has a large degree of freedom in selecting a mounting position and has been considered difficult in the past. It can also be installed on the exhaust manifold that was previously used.

[Brief description of drawings]

FIG. 1 is a sectional view showing a catalytic converter of the present invention.

FIG. 2 is a sectional view showing an example of a conventional catalytic converter.

[Explanation of sign]

 1 Casing 1a Inner peripheral surface 2 Honeycomb catalyst carrier 2a Outer peripheral surface 3 Buffer material 4 Buffer material 5 Mat 6 Exhaust inlet 7 Exhaust outlet 8 Holding portion 9 Step portion 10 Casing 11 Catalyst carrier 12 Perforated plate

Claims (1)

[Scope of utility model registration request] 1. A tubular casing and a catalyst carrier supported in the casing. The catalyst carrier is formed by lightly compressing a large number of ferritic stainless steel fibers containing aluminum and chromium. A catalytic converter characterized in that a large number of fine whiskers are formed on the surface of each fiber, and the catalyst is carried on the surface of each fiber by the large number of whiskers.