JPH04260443A - Catalyst carrier - Google Patents

Abstract

PURPOSE:To provide a catalyst carrier reduced in the flow resistance of exhaust gas and showing efficient purifying action. CONSTITUTION:A catalyst carrier 3 is arranged in the large caliber case 41 provided in an exhaust pipe 4 and constituted by laminating and winding a corrugated plate 1 and a flat plate 2. The spaces of the corrugated plate 2 closed by the flat plate 1 become gas flow passages P and small holes 11, 21 permitting exhaust gas to pass are provided to the corrugated plate 1 and the flat plate 2. The exhaust gas flowing in the inner peripheral part of the catalyst carrier 3 at a high speed under high pressure passes through the small holes 11, 21 by the pressure difference with the outer peripheral part thereof to diffuse to the outside and flows in the gas flow passages P of the outer peripheral part. By this constitution, the flow velocity distribution of the exhaust gas flowing through the catalyst carrier becomes uniform and pressure loss can be reduced. The entire catalyst in the carrier 3 including the outer peripheral part thereof contributes to the purification of exhaust gas to achieve efficient purification.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst carrier for supporting an exhaust gas purifying catalyst for a vehicle.

0002

2. Description of the Related Art In FIG. 4, an exhaust gas purification device is provided in the middle of an exhaust pipe 4 of an engine E. This device includes a three-way catalyst for exhaust gas purification in a case 41 having a large diameter. A honeycomb-shaped catalyst carrier 3 supporting the like is disposed. The catalyst carrier 3 is made of a laminated metal corrugated plate with a catalyst supported on the plate surface and a flat plate, and the exhaust gas flowing through the corrugated plate space closed by the flat plate is purified by the catalyst as an air flow path. .

0003

[Problems to be Solved by the Invention] By the way, in order to reduce the pressure loss in the catalyst carrier, the outer diameter of the catalyst carrier 3 is made larger than the diameter of the exhaust pipe 4 as described above. When examining the flow velocity distribution, as shown in Figure 5, the flow velocity v at the inner periphery of the carrier is large due to the inertia of the exhaust gas, but it is small at the outer periphery, indicating that the large diameter contributes effectively to reducing the pressure drop. In addition, the catalyst provided in the air flow path at the outer periphery is not effectively utilized.

[0004] The present invention is intended to solve these problems, and aims to provide a catalyst carrier that reduces pressure loss by uniformizing the flow velocity distribution in the catalyst carrier, and that exhibits an efficient purification effect by effectively utilizing the catalyst. shall be.

[0005]

[Means for Solving the Problems] To explain the structure of the present invention, corrugated metal plates 1 (FIG. 1) and flat plates 2 each having a catalyst supported on their plate surfaces are laminated alternately, and the space inside the corrugated plates 1 is covered. A catalyst carrier 3 is configured as an air flow path P, and the catalyst carrier 3 is connected to a gas flow pipe 4.
The corrugated plate 1 and the flat plate 2 are housed in a large diameter portion 41 formed in a part thereof, and a large number of small holes 11 and 21 are formed in the plate surfaces of the corrugated plate 1 and the flat plate 2 to allow gas to flow therethrough.

In this configuration, in the catalyst carrier 3 provided in the large diameter portion 41, the flow velocity is faster and the pressure is higher in the inner peripheral portion where gas flows than in the small diameter general portion of the gas flow pipe 4. Therefore, a pressure difference is generated between the airflow channel P located on the inner periphery and the airflow channel P located on the outer periphery, and the small holes 1 of the corrugated plate 1 and the flat plate 2
1 and 12, the gas flows out from the air flow path P in the inner circumference to the air flow path P in the outer circumference. Thus, the gas flow rate is averaged over the entire catalyst carrier 3, reducing the air flow pressure loss during the flow of the carrier 3, and all the catalysts act equally on the gas, achieving an efficient catalytic function.

[0007]

[Embodiment] In FIG. 1, an engine exhaust pipe 4, which is a gas flow pipe, has its diameter enlarged in the middle to form a large diameter cylindrical case 41, and a catalyst carrier 3 is disposed inside the case 41. . Catalyst carrier 3
The metal corrugated plate 1 and the flat plate 2, each carrying a catalyst on their plate surfaces, are wound and laminated in a manner described later, and the outer diameter is large enough to slidably contact the inner circumferential wall of the case 41. It's sato. The space of the corrugated plate 1 sandwiched between the flat plates 2 forms an air flow path P, and the exhaust gas is purified by the catalyst while passing through this. The corrugated plate 1 and the flat plate 2 are provided with a large number of small holes 11 and 21 that allow exhaust flow to flow therethrough.

A circular stopper plate 5 is provided at the downstream opening of the case 41 to close the opening, and the outer periphery of the stopper plate 5 is fixed to the inner periphery of the case 41 at a flange portion by welding or the like. In addition, a large number of small holes 51 having the same diameter as the small holes 11 and 21 are formed in the plate surface. As shown in FIG. 2, the catalyst carrier 3 is made by stacking a corrugated plate 1 and a flat plate 2, each having a large number of small holes 11 and 21, around a rotating core 6 and winding them up in a generally circular shape. has been done.

In the catalyst carrier 3 having such a structure, when exhaust gas flows into the case 41 from the exhaust pipe 4, the exhaust gas flows into the inner periphery of the carrier 3 at a high flow velocity due to inertia, and the pressure increases. do. This pressure increase creates a pressure difference between the air flow path P on the inner circumference and the outer circumference of the catalyst carrier 3, and a part of the exhaust gas flows outward through the small holes 11 and 21 of the corrugated plate 1 and the flat plate 2. (Fig. 3). As a result,
The exhaust gas flow velocity distribution throughout the carrier 3 is made uniform, and pressure loss during circulation is reduced. Further, since the catalyst in the entire carrier 3 including the outer peripheral portion contributes to the purification of exhaust gas, an efficient purification effect is exhibited.

[0010] When high-temperature exhaust gas passes through, a large temperature gradient occurs at the outermost portion of the catalyst carrier 3 that is exposed to the outside air, but the difference in expansion rate between the case 41 and the catalyst carrier 3 is due to Since it can be slid and expanded and contracted within the case 41, it is absorbed, and no peeling or cracking occurs due to stress generation.

[0011]

[Effects of the Invention] As described above, according to the catalyst carrier of the present invention,
The flow resistance of exhaust gas, etc. can be kept low, and efficient catalytic action can be realized.

[Brief explanation of the drawing]

FIG. 1 is an exploded sectional view of an exhaust pipe in a catalyst carrier installation part.

FIG. 2 is a perspective view showing a method for manufacturing a catalyst carrier.

FIG. 3 is a diagram showing the flow velocity distribution within the catalyst carrier.

FIG. 4 is a partially sectional plan view of the engine exhaust system.

FIG. 5 is a diagram showing flow velocity distribution within a conventional catalyst carrier.

[Explanation of symbols]

1 Corrugated plate 11 Small hole 2　Flat plate 21 Small hole 3 Catalyst carrier 4 Exhaust pipe (gas flow pipe) 41 Case (large diameter part) 5 Stopper plate

Claims (1)

[Claims] Claim 1: A catalyst carrier is constructed by alternately stacking metal corrugated plates and flat plates each carrying a catalyst on the plate surface, and the corrugated plate space serves as an air flow path, and the catalyst carrier is connected to a gas flow pipe. A catalyst carrier characterized in that the catalyst carrier is housed in a large diameter portion formed in a part of the corrugated plate and the flat plate, and has a large number of small holes formed in the plate surfaces of the corrugated plate and the flat plate to allow airflow to flow therethrough.