JPH06108835A - Catalyst muffler - Google Patents

Abstract

PURPOSE:To provide a catalyst muffler which is provided with an exhaust gas purification function and an exhaust gas noise reduction function, especially an injected gas noise absorption function and can lower production cost without causing the influence of deformation upon a catalyst body due to heat. CONSTITUTION:Steel wool 10 is charged or inserted into a cavity part in a muffler body, a tail pipe 3 or the like, and a catalyst is carried on the steel wool. In the catalyst muffler of an internal combustion engine which is provided with an insertion pipe 5 and/or the tail pipe 3, one end or both the ends of the pipe are closed and many holes are drilled in a pipe wall part, and a cloth- like steel net is wrapped around the pipe to carry the catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic muffler applied to an exhaust purification system of an internal combustion engine.

[0002]

2. Description of the Related Art FIG.
FIG. 3 shows a vertical sectional view of the catalytic converter disclosed in JP-A-3-44928). The configuration and operation will be described with reference to FIG. The main body 01 is configured by joining a front main body 01c and a rear main body 01d, and a honeycomb catalyst 07 made of a metal-based carrier having honeycomb-shaped pores integrally formed in the axial direction is housed in the rear main body 01d. Between the inner wall of the rear main body 01d and the outer periphery of the honeycomb catalyst 07, a cushioning material in which silliglass wool 09 and steel wool 010 are stacked is interposed to hold the catalyst, and axial positioning of the catalyst in the main body 01 is performed. Ring-shaped end holding members 06a and 06b are used at both front and rear ends. The exhaust gas of the engine flows into the catalytic converter from an exhaust port (not shown) through an inlet 022, is oxidized and / or reduced by the honeycomb catalyst 07, and then flows out from an outlet 032 to a silencer (not shown).

FIG. 6 is a vertical cross-sectional view of a catalyst muffler in which a catalyst is incorporated into the muffler body as one of the constituent members. The configuration and operation will be described with reference to FIG. The interior of the muffler body 01 is partitioned by a partition plate 04 into two chambers, a front chamber 01a and a rear chamber 01b, and an inner end of the inlet pipe 02 opening in the front chamber 01a is closed and a large number of pipes are provided on the outer periphery of the pipe. Small holes are drilled. In the central portion of the partition plate 04, a monolithic honeycomb catalyst 07 made of a metal-based carrier integrally formed with honeycomb-shaped pores in the axial direction is held with a buffer material as shown in FIG. 5 interposed therebetween. The two chambers 01a and 01b communicate with each other. Reference numeral 03 denotes a tail pipe, and a mesh is usually attached to the outlet end thereof. The exhaust gas expands rapidly through a large number of small holes of the inlet pipe 02 and honeycomb-shaped fine holes of the catalyst 07,
Exhaust pulsation is attenuated in the two expansion chambers, and the honeycomb catalyst 0
The air pollutants contained in the exhaust gas are oxidized and /
Or, it is reduced, and both effects of noise reduction and exhaust gas purification are obtained.

[0004]

In the above-mentioned catalyst muffler of the prior art, a honeycomb-like integrally formed (Morris type) carrier for supporting a catalyst is elastically held by interposing siliglass wool or steel wool as a cushioning material. The reason is as follows. That is, the catalyst is about 300 ° C to 9 ° C.
Since the operating temperature range is 00 ° C, it is necessary to release strain and stress due to heat for the integrally formed carrier, and when a gap is created between the carrier and the holder (for example, the partition plate in Fig. 6), this gap It is necessary to prevent the untreated exhaust gas from blowing through and the impact of the carrier from vibration. In addition, the following problems are still pointed out in the above-mentioned measures by the conventional technique. Since the number of parts required to hold the carrier is large and a cushioning material having a considerable compressibility needs to be inserted in a compressed state during assembly, there is room for improvement in cost and productivity.

An object of the present invention is to solve the above-mentioned problems and to have an exhaust gas purifying function as well as an exhaust noise reducing function including an absorbing effect of fumes, without the catalyst carrier being affected by heat deformation. It is to provide a catalytic muffler that can reduce the production cost.

[0006]

A catalytic muffler for an internal combustion engine according to a first aspect of the present invention is a hollow muffler 1b in a muffler body 1, a tail pipe 3 or the like filled with or inserted with steel wool 10, and the steel wool is provided with a catalyst. A second aspect of the present invention is a catalyst muffler of an internal combustion engine having an insertion pipe 5 and / or a tail pipe 3, wherein one end and / or both ends of these pipes are closed and a large number of small holes are formed in a pipe wall portion. Wrap around the cloth-like steel net 20,
It is characterized in that a catalyst is supported on the steel net.

[0007]

Since the porous body is formed of the fibrous and elastic material such as the steel wool 10 and the steel net 20 and the catalyst is carried on the porous body itself, the problem caused by the thermal deformation of the carrier, which has been pointed out in the conventional example, is a problem. Has been resolved. Since the steel wool 10 and the steel net 20 form a porous body, the steel wool 10 and the steel net 20 absorb acoustic energy and act as a sound absorbing muffler. It also has the effect of reducing fumes. Regarding reduction of fumarolic noise by porous body,
(Actual application Sho 63-90012, Actual application 60-180710)
There is a prior application such as. Further, the catalyst adhered to the surface of steel wool or steel net oxidizes CO and HC or reduces NO _x , depending on the type, to purify exhaust gas. In addition, the number of required parts can be reduced and the production process can be simplified, resulting in cost reduction.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Regarding the catalyst muffler according to the present invention, sectional views of an embodiment according to the first invention are shown in FIGS. 1 and 2, and sectional views of an embodiment according to the second invention are shown in FIGS. 3 and 4. The configuration and operation of an embodiment of the catalytic muffler according to the present invention will be described with reference to FIGS. FIG. 1 (first embodiment according to the first invention)
The catalyst muffler shown in FIG. 2 is open on the muffler body 1 and the inlet 22 side through which exhaust gas flows into the body, the end is closed in the body, and a large number of small holes 21 are bored in the pipe wall. It is composed of an inlet pipe 2 and a tail pipe 3 into which a steel wool 10 carrying a catalyst is inserted. The steel wool 10 is woven into a mat shape and wound into a cylindrical shape, and is inserted into the tail pipe 3. First, the catalyst is supported in the inserted state, and then the tail pipe 3 is fixed to the main body 1 and then inside the tail pipe 3. A stop pin 35 is attached to prevent the steel wool 10 from moving. Steel wool 1
The material of No. 0 is the same kind of material as a stainless steel foil of a so-called metal-based carrier catalyst in which a thin stainless material is a carrier of a catalyst component, and is a plate material or a wire material having a thickness or diameter capable of maintaining elasticity.

Exhaust gas discharged from an exhaust port of an engine (not shown) flows into the inlet pipe 2 through the inlet 22 and is ejected into the muffler body 1 from a plurality of small holes 21 formed in the inlet pipe to rapidly expand. , Steel wool supporting catalyst components 10
Is discharged into the atmosphere through the tail pipe 3 in which is inserted. Due to the action during this period, the sound deadening effect and the exhaust gas purification effect are both realized.

In the catalytic muffler shown in FIG. 2 (second embodiment according to the first invention), the inside of the muffler body 1 has a large number of holes 41.
The front chamber 1a and the rear chamber 1b are divided into upper and lower halves via a partition plate 4 having a. The indoor end of the inlet pipe 2 inserted into the antechamber 1a is closed, and the pipe wall has a large number of small holes 21 that open into the room.
Has been drilled. Inside the rear chamber 1b is a pipe having the same structure as the above-mentioned inlet pipe, and the side opposite to the indoor side closed end is the exhaust outlet 32.
The tail pipe 3 that opens to the outside is disposed in parallel with the partition plate 4. Steel wool 10 is filled in the rear chamber 1b so as to enclose the tail pipe 3, and the catalyst component is supported on the steel wool by the plating liquid of the catalyst component in the filled state, and the plating liquid after the loading is completed is the lower portion of the muffler body 1. The small holes 11 are discharged, and after the discharge is completed, the small holes 11 are sealed. Exhaust gas flows into the muffler body 1 from the inlet 22 of the inlet pipe 2 and is discharged into the atmosphere from the outlet 32 of the tail pipe 3. By the action during this period, both effects of noise reduction and exhaust gas purification can be obtained.

In the catalytic muffler shown in FIG. 3 (third embodiment according to the second aspect of the invention), the inside of the muffler main body 1 is joined to the inlet pipe 2 and the rear chamber 1b is joined to the tail pipe 3.
Are partitioned into two chambers in the axial direction via a partition plate 4. An insertion pipe 5 penetrating from the front chamber 1a to the rear chamber 1b is fixed to the central portion of the partition plate, both ends of the insertion pipe are closed, and the pipe wall is opened to the front chamber 1a and the rear chamber 1b. A large number of small holes 51 are formed. First, the insertion pipe 5 is inserted into the partition plate 4 and fixed thereto, and then the cloth-shaped steel net 20 is wound around the outer periphery of the insertion pipe 5 and fixed by the retaining ring 52, and in this state, the catalyst component is attached to the steel net 20. After being supported, the whole is assembled as a catalyst muffler. Exhaust gas flows from the inlet 22 through the inlet pipe 2 into the antechamber 1a and expands, passes through the catalyst layer of the steel net 20 into the pipe of the insertion pipe 5 through the small hole 51, and proceeds to the downstream side. From 51 through the catalyst layer of the steel net 20 again, it blows out into the rear chamber 1b and expands rapidly,
It is discharged into the atmosphere from the outlet of the tail pipe 3. It is the same as the above-mentioned conventional example that both the effects of noise reduction and exhaust gas purification can be obtained.

The structure and operation of the catalytic muffler shown in FIG. 4 (fourth embodiment according to the second invention) is similar to that of the second embodiment described above. In this embodiment, there is no compartment division in the main body by the partition plate as in the second embodiment, and the cloth-like steel net 20 wound around the tail pipe 3 takes charge of the exhaust gas purification action. The manufacturing method of the catalyst portion is similar to that of the third embodiment.

[0013]

Since the present invention is constructed and operates as described above, the following effects can be obtained. By supporting a catalytic component on steel wool and / or steel net itself, which is fibrous and has elasticity, both the functions of exhaust gas purification and acoustic energy absorption can be performed at the same time, and ceramic-based or metal-based The production cost can be reduced by significantly reducing the number of required parts and steps without causing problems such as stress and gaps due to thermal deformation that occur when the catalyst carrier is used due to the integral structure of the system.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a catalytic muffler according to a first embodiment of the first invention.

FIG. 2 is a vertical sectional view of a catalyst muffler according to a second embodiment of the first invention.

FIG. 3 is a vertical sectional view of a catalyst muffler according to a third embodiment of the second invention.

FIG. 4 is a vertical sectional view of a catalyst muffler according to a fourth embodiment of the second invention.

FIG. 5 is a vertical sectional view of a conventional catalytic converter.

FIG. 6 is a vertical sectional view of a catalyst muffler according to a conventional technique.

[Explanation of symbols]

1 ... Muffler body, 1a ... Front chamber, 1b ... Rear chamber, 11 ... Small hole, 2 ... Inlet pipe, 21 ... Small hole, 22 ... Inlet, 3 ... Tail pipe, 31 ... Small hole, 32 ... Exit, 35 ... Stop pin, 4
... Partition plate, 41 ... Hole, 5 ... Insertion tube, 51 ... Small hole, 52 ...
Retaining ring, 10 ... Steel wool, 20 ... Steel net.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mihide Nakatani No. 1 Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Nagoya Machinery Works

Claims (2)

[Claims] 1. A steel wool (10) is filled or inserted into a cavity (1b) or a tail pipe (3) in a muffler body (1), and a catalyst is supported on the steel wool. Catalyst muffler for internal combustion engine. 2. In a catalytic muffler of an internal combustion engine having an insertion pipe (5) and / or a tail pipe (3), one end or both ends of these pipes are closed, and a large number of small holes are provided in the pipe wall portion, and the periphery thereof is provided. A catalyst muffler for an internal combustion engine, characterized in that a cloth-shaped steel net (20) is wound around a steel net and a catalyst is carried on the steel net.