JPS6339762B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the treatment of exhaust gas from a domestic engine, and more particularly to a catalytic converter for treating exhaust gas to convert its undesirable components into harmless forms.

Such catalytic converters are connected within the exhaust system of an engine to pass exhaust gases from the engine through a bed of catalytic material held within the converter, which removes carbon monoxide and non-carbon monoxide from the exhaust gases. It oxidizes the hydrocarbons of combustion to form carbon dioxide and water and/or reduces nitrogen oxides.

A catalyst is held inside a porous catalyst holder, which is housed in a housing, and exhaust gas to be treated is introduced into a space formed between the upper part of the housing and the upper part of the catalyst holder, and the exhaust gas to be treated is introduced into the space formed by the upper part of the housing and the upper part of the catalyst holder. Various catalytic converters have been proposed in which the exhaust gas passes through a porous catalyst holder by flowing the exhaust gas into a space formed between the lower part and the lower part of the catalyst holder, but none of them have been proposed. There are durability issues regarding gas leaks.

Examples of such known catalytic converters include a catalytic retainer comprising a perforated upper plate, a perforated lower plate, a vertical plate sealingly closing these upper and lower plates at their upstream ends, and also a perforated lower plate at their upstream ends. Some consist of vertical plates that close off the sides. In this case, the upper and lower plates extend transversely to the gas flow direction and are sandwiched between the flanges of the outer housing plate in order to allow the exhaust gas to flow past the catalyst holder. , the lower end of the vertical plate is in sealing contact with the housing at the upstream end, and similarly the upper end of the vertical plate is in sealing contact at the downstream end. Due to the construction, it is necessary to achieve a sealed state through such a sealed contact (for example, US Pat. No. 3,600,142).

Other known catalytic converters include, for example, U.S. Pat.
The bed has a substantially uniform cross-section for gas flow at all points along the entire axial length of the transducer. However, this converter does not have a catalyst retainer member whose ends are sandwiched between the flanges of the housing member and which are secured and sealed at the ends. This patent also includes a catalyst retainer member extending imperforately into the inlet passageway at the bottom of the incoming exhaust gas and extending imperforately into the outlet passageway at the top of the exiting exhaust gas. do not have. Furthermore, this patent does not have top and bottom retainer members forming sloped catalyst beds with sidewalls that respectively increase and decrease in depth from the exhaust gas inlet to the exhaust gas outlet. The converter of this U.S. patent thus addresses the problems of transducer sticking, sealing, flow uniformity, and durability, which are issues in devices that withstand the thermal stress caused by the inevitable temperature gradients and rapid temperature changes in catalytic converters. lack of consideration.

However, since the catalytic converter is subject to such large temperature changes that the plates "warp" and "bend", it is practically impossible to maintain a sealed state with these known structures. In other words, as such a sealed part is used, it easily opens due to "warping" or "bending" of the plate part, which becomes a leak path that quickly circulates the catalyst and is harmful to the atmosphere. release gas,
It becomes an obstacle to effective exhaust gas treatment. Considering the basic function of a catalytic converter, the occurrence of a leak that quickly bypasses the catalyst means that the converter is unusable or damaged. Therefore, known catalytic converters include:
The drawback was that it lacked durability.

An object of the present invention is to obtain a catalytic converter for an internal combustion engine that has a strong structure, is free from the possibility of leakage that quickly circulates the catalyst, and is highly durable.

The converter according to the invention provides a uniform flow and low pressure drop of the exhaust gas through the catalyst bed. Its low profile conforms to the limited space requirements for placement under the vehicle, and the upward and downward extensions of the converter retainer facilitate the inflow of exhaust gases. and leaks out. Accordingly, according to the features of the invention:
The housing and retainer are secured and sealed together and provide low resistance to gas flow. A sloped catalyst bed providing a uniform pressure gradient is obtained with a simple cage construction in which the sidewall depths of the top and bottom cage members increase and decrease, respectively, to provide a slight slope.

In the exhaust gas catalytic converter for an internal combustion engine of the present invention, the catalyst retainer is formed by top and bottom retainer members, and the top and bottom retainer members form the catalyst housing portion together with the top and bottom porous portions, respectively. the top retainer member has an upwardly recessed portion extending from one end of the side wall portion toward the inlet channel in a nonporous manner; The facing recess extends axially further along the inlet half cylinder 66 of the bottom housing member 14 and forms an exhaust gas inlet cylinder 56 with the inlet half cylinder 64 of the top housing member 12 to form the exhaust gas inlet cylinder 56. The upward recess of the retainer member and the inlet semi-cylindrical portion of the top housing member are directly connected to the inlet cylindrical member of the exhaust system; the bottom retainer member is connected to the inlet flow path from one end of its side wall. and an upwardly extending recess in the bottom retainer member that further extends axially along and overlaps the inlet half-cylinder 66 of the bottom housing member. the further axially extending upwardly recessed portion of the top retainer member and the inlet semi-cylindrical portion of the bottom housing member;
The bottom retainer member has a downwardly directed recess extending from the other end of the sidewall toward the outlet passageway in a nonporous manner, and the downwardly directed recess of the bottom retainer member is connected to the top housing member 12. The exhaust gas outlet cylinder 58 further extends axially in a non-porous manner along the outlet semi-cylindrical portion 64 and forms an exhaust gas outlet cylinder 58 with the outlet semi-cylindrical portion 66 of the bottom housing member 14 to form a downward recess of the bottom retainer member. the outlet semi-cylindrical portion of the bottom housing member is directly connected to the outlet cylindrical member of the exhaust system;
The top retainer member has a downwardly directed recess extending from the other end of the side wall toward the outlet passage, the downwardly recessed portion of the top retainer member further axially extending into the outlet half of the top housing member. extending along the cylindrical portion 64 and overlapping the outlet semi-cylindrical portion with said further axially extending downwardly recessed portion of the bottom retainer member and the outlet semi-cylindrical portion of the top housing member. The inlet semi-cylindrical part, the dish-shaped part and the outlet semi-cylindrical part constituting the top and bottom housing members are each integrally formed of the same material; The flange portion of the housing is integrally provided over the entire periphery except for the exhaust gas inlet edge and the outlet edge; and the exhaust gas inlet edge and the outlet edge are provided on the periphery of the top and bottom retainer members. A flange portion of the catalyst holder is integrally provided over the entire periphery except for the flange portion of the catalyst holder, and the flange portion provided on the periphery of both the cage members is clamped by the flange portion provided on the periphery of both the housing members. further, the catalyst receiving portions of the top and bottom retainer members slope upwardly from the exhaust gas inlet 56 toward the exhaust gas outlet 58 and have a substantially uniform depth;
The sidewalls of the top and bottom retainer members are then characterized by increasing and decreasing depths, respectively, from the exhaust gas inlet 56 to the exhaust gas outlet 58.

Additionally, it is desirable that the flow of gas through the catalyst bed be substantially uniformly distributed throughout the bed to obtain maximum catalyst life and optimum conversion. Generally uniform distribution is achieved by the catalyst containment formed by the top and bottom cage members. That is, this catalyst accommodating portion has a substantially uniform depth that slopes upward between the exhaust gas inlet and outlet. This slightly sloped catalyst housing reduces the overall height of the converter compared to if the inlet and outlet gas flow paths were of constant height.

In particular, the converter of the present invention is highly resistant to gas leaks that quickly displace the catalyst, has a low profile profile, and does not restrict gas flow.

The low profile profile allows the top and bottom retainer members to be sandwiched between the top and bottom housing members over their entire periphery, and the depth of the top and bottom retainer members to be limited to the gas inlet and outlet relative to the housing member. This is accomplished by defining a substantially uniform depth of catalyst receptacle that is slightly inclined relative to the housing by varying inversely between

Durability is achieved by extending an upward recess in a non-porous state from one end of the side wall of the top retainer member toward the inlet flow path, and extending the upward recess further along the inlet semi-cylindrical portion of the bottom housing member. The bottom retainer member has a downwardly recessed portion extending from the other end of the side wall thereof toward the outlet flow path so as to extend in an axial direction without holes so as to be directly connected to the inlet side cylindrical member of the exhaust system. the downwardly recessed portion extending further axially along the outlet semi-cylindrical portion of the top housing member in a non-porous manner so as to be directly connected to the outlet side cylindrical member of the exhaust system; This is achieved by Durability also includes having an upwardly extending recess in the bottom retainer member extending from its sidewall toward the inlet flow path, and connecting the upwardly recessed portion of the top retainer member to the further axially extending upwardly recessed portion of the top retainer member. and an inlet semi-cylindrical portion of the bottom housing member, and the top retainer member has a downwardly recessed portion extending from a side wall thereof toward the outlet passageway, and the downwardly directed recessed portion is held by the bottom retaining member. This is accomplished by sandwiching the further axially extending downwardly recessed portion of the container member and the outlet semi-cylindrical portion of the top housing member. Durability is also achieved by sandwiching the laterally extending flange portions of the retainer member in an overlapping manner between integral flange portions of the housing member. That is, the laterally extending flange portions of the retainer and the axially extending portions of the top and bottom retainer members cooperate to prevent gas leaks that would quickly displace the catalyst and increase durability.

Minimizing gas flow restriction is also achieved by an elongated catalyst retainer structure that corresponds to the portions that flow gas into and out of the converter. The structure of this catalytic converter provides a streamlined interior for exhaust gases to easily flow into the converter.
Allow it to flow out of the transducer. The top and bottom retainer members define a slightly sloped catalyst receptacle spaced at varying spacings within the top and bottom housing members but having a substantially constant depth. That is, the spacing between the top retainer member and the top housing member decreases from the gas inlet to the outlet, thereby creating a decreasing cross-section for the incoming gas flow and providing a substantially constant pressure gradient. Give. Similarly, the spacing between the bottom retainer member and the bottom housing member increases progressively from the gas inlet to the outlet, creating a progressively increasing cross-section for the exiting gas, again providing a substantially constant pressure gradient. Give. This means that in the cage of the present invention,
This is accomplished by increasing and decreasing the depth of the dish-shaped portions of the top and bottom retainer members, respectively, from the gas inlet to the outlet.

The present invention and its implementation method will be explained in detail below with reference to the drawings.

In the figures, similar parts, apart from minor differences, are given the same reference numerals.

Figures 4 to 12 show the cylindrical member 6 on the exhaust system inlet side.
A preferred embodiment of the catalytic converter has a housing 10, which is connected to the outlet cylindrical member 62.
0 is preferably formed of high chromium stainless steel or coated or plated steel to withstand the corrosive effects of hot salts and gases. The housing 10 consists of a top housing member 12 and a bottom housing member 14, each of which has a respective dish-shaped portion, which already has a vertical side wall portion 1.
6,18.

The top housing member 12 has an inlet semi-cylindrical portion 64 (on the left in FIGS. 6 and 12) on the upstream side and an outlet semi-cylindrical portion 64 on the downstream side (on the right in FIGS. 6 and 12). The inlet semi-cylindrical portion 64 and the outlet semi-cylindrical portion 64 are integrally formed of the same material. The bottom housing member 14 also has an inlet semi-cylindrical portion 66 (left side in FIGS. 6 and 12) on the upstream side and an outlet semi-cylindrical portion 66 on the downstream side.
The dish-shaped portion of the bottom housing member 14, the inlet semi-cylindrical portion 66, and the outlet semi-cylindrical portion 66 are integrally formed of the same material. Additionally, top and bottom housing members 12,
Flange portions 20 and 22 are provided on the peripheral edge of 14 over the entire periphery except for the exhaust gas inlet edge and outlet edge for clamping a flange of a retainer member, which will be described later.
are integrated.

Mounted within the housing 10 is a sloped catalyst retainer 24 consisting of a top retainer member 26 and a bottom retainer member 28 (the tilt will be discussed below).

The top and bottom retainer members 26, 28 have a top porous section 30 and a bottom porous section 34 for passage of exhaust gases.
The top and bottom retainer members 26, 28 further have non-porous sidewalls 38, 40 which together with the top porous portion 30 and bottom porous portion 34 form a catalyst receiving portion 46.

A top aperture 30 of the top retainer member 26 is spaced apart from the top housing member 12 and includes a plurality of regularly spaced perforations 32' approximately 1/16 inch in size. has. Similarly, the bottom aperture 34 of the bottom retainer member 28 is spaced apart from the bottom housing member 14 and has a small aperture 36' formed therethrough. opening 32',
36' may take other forms. For example, they may be in the form of holes extending through the top or bottom retainer member, or projecting outwardly from the top or bottom retainer member and recessed in the direction of the incident gas flow (first
It may be formed as a lance-shaped aperture forming a protrusion (as indicated at 32, 36 in the embodiment illustrated in FIGS. 4-11), or alternatively as shown in FIGS.
As is the case with the preferred embodiment shown in the figures, the armor window 32' is made by cutting out a metal section from the plane of the plate and pressing the section to form several rows of regularly spaced arcuate armor windows. , 36' with a height of approximately 0.065 inches (1.65 mm), a width of approximately 0.15 inches (3.81 mm) and a length of approximately 0.5 inches (12.7 mm), with a spacing between successive aligned armor windows. is approximately 0.25 inches (6.35 mm) and the spacing between each row is 0.15 inches (3.81 mm).

Catalyst housing 46 is filled with a desired catalytic material 48, which is packaged therein to form a catalytic bed, as described below.

The catalyst may be used in any form, but is preferably in the form of pellets, extrudates, or spheres about 1/8 inch (3.17 mm) in size, with or without a support or carrier. good. The catalyst is also preferably distributed on or impregnated with a support or carrier, which may or may not contribute to the catalytic activity of the material. As the catalyst, any suitable oxidation or reduction catalyst, or a catalyst that can perform both oxidation and reduction, and is effective for a long period of time up to an operating temperature of 870° C., may be used. It is desirable that the catalyst bed be relatively shallow to minimize back pressure within the exhaust system. A bed approximately 2 inches (50.8 mm) deep has been found to be suitable. As shown in FIG. 8, the catalytic material 48 occupies the space between each arcuate armor window 32', but is of sufficient size so that it is confined by and does not pass through the opening formed by the armor window. .

The top retainer member 26 has an upwardly recessed portion extending from one upstream end of its side wall toward the inlet flow path in a nonporous manner, and the upwardly recessed portion of the top retainer member 26 is connected to the bottom housing member. 14 further extends axially in a nonporous manner 68 along the inlet half cylinder 66 of the top housing member 12 and forms an exhaust gas inlet cylinder 56 with the inlet half cylinder 64 of the top housing member 12 . The upward recess and the inlet semi-cylindrical portion of the top housing member are adapted to be directly connected to the inlet cylindrical member 60 of the exhaust system. The bottom retainer member 28 also has an upwardly recessed portion extending from one upstream end of the sidewall toward the inlet flow path, and the upwardly recessed portion of the bottom retainer member further extends axially toward the bottom housing. The further axially extending upwardly recessed portion 68 of the top retainer member 26 extends 70 along and overlaps the inlet half-cylinder section 66 of the member 14 and the bottom housing. and the inlet semi-cylindrical portion of member 14.

The bottom retainer member 28 has a downwardly directed recess extending from the other end of the side wall toward the outlet flow path in a nonporous manner, and the downwardly directed recess of the bottom retainer member 28 is connected to the top housing member 12 . Further axially extending 74 along the outlet semi-cylindrical portion 64 and forming an exhaust gas outlet cylindrical portion 58 with the outlet semi-cylindrical portion 66 of the bottom housing member 14 to form a downwardly recessed portion of the bottom retainer member 28 and the bottom housing. The outlet semi-cylindrical portion 66 of the member is directly connected to the outlet side cylindrical member of the exhaust system.

The top retainer member 26 has a downwardly directed recess extending from the other end of the sidewall toward the outlet flow path, the downwardly recessed portion of the top retainer member further extending axially toward the outlet of the top housing member 26. a portion 74 of the further axially extending downwardly recessed portion of the bottom retainer member extending along and overlapping the exit half-cylinder portion 64; and an exit half-cylinder portion of the top housing member. is held by.

As mentioned above, the top housing member 12 includes a first
As shown most clearly in FIG. 2, semi-cylindrical portions 64 are provided on the upstream and downstream sides, respectively. The bottom housing member 14 also includes semi-cylindrical portions 66 on the upstream and downstream sides.

As shown in Figure 6 (left side), on the upstream side,
A portion of the upwardly recessed portions of both retainer members overlap and extend axially with the inlet half-cylinder portion 66 of the bottom housing member 14 and together with the inlet half-cylinder portion 64 of the top housing member 12 form a cylindrical exhaust gas inlet. A semi-cylindrical portion 56 is formed. Therefore, the top housing member 12
and catalyst retainer 24 are connected directly at their ends to the inlet cylindrical member 60 of the exhaust system by a weld 106 (FIGS. 4 and 6).

On the other hand, on the downstream side, as shown on the right side of FIG. 6, a portion of the downward recessed portions of both retainer members overlaps the outlet semi-cylindrical portion 64 of the top housing member 12 and extends in the axial direction, A cylindrical exhaust gas outlet cylinder 58 along with an outlet semi-cylindrical part 66 of the bottom housing member 14
form. Therefore, the bottom housing member 1
4 and catalyst retainer 24 are directly connected at their ends to the exhaust system outlet cylindrical member 62 by a weld 106 (FIGS. 4 and 6).

Thus, in this embodiment, on the inlet side, the bottom retainer member 28 is attached to the top retainer member 26 by the weld 106 and is also connected to the inlet cylindrical member 60 of the exhaust system, On the outlet side, the top retainer member 26 is attached to the bottom retainer member 28 by the weld 106 and is attached to the outlet side cylindrical member 62 of the exhaust system.
is also connected to.

Next, the flanges 20 and 22 should be attached to the peripheral edges of the top and bottom retainer members 26 and 28 of the catalyst retainer 24 over the entire periphery of the catalyst retainer 24 except for the exhaust gas inlet and outlet edges. flange portion 42,
44 is integrally provided, and both retainer members 2
Imperforate sidewalls 38, 40 of 6, 28 continue therefrom to the laterally extending flange portions 42, 44, the depth of the sidewalls increasing from one end of the top retainer member 26 to the other. Increased bottom retainer member 28
conversely decreases from the one end side to the other end side, and when both the retainer members 26 and 28 are combined with each other, a catalyst accommodating part 46 is formed between them, and the accommodating part As shown in Figures 6 and 11, both housing members 1 have approximately the same depth.
2 and 14, both housing members 1
2 and 14 to provide a filling chamber with a progressively decreasing cross section for the incoming exhaust gas, thereby ensuring a fairly constant pressure gradient, and conversely provide a filling chamber with a gradually increasing cross section for the outgoing exhaust gas, This provides a nearly constant pressure gradient.

The flange portions 20, 22, 44 of the top and bottom housing members 12, 14 and the top and bottom retainer members 26, 28 project outwardly and are interengageable with these members over substantially their entire circumference. surfaces 20', 22', 42', 44' (FIG. 12). Figures 6, 7 and 11
As shown in the figure, the flange portions 42 and 44 of the catalyst holder 24 are connected to the flange portions 20 and 44 of the housing 10, respectively.
22 to form a flange portion of a four-layer sandwich structure, and the sandwich trench is suitably sealed by a substantially continuous outer periphery weld 50 to provide internal and external sealing. Therefore, both retainer members 26,2
The flange portions 42 and 44 provided on the periphery of both housing members are the flange portions 20 and 44 provided on the periphery of both housing members.
22. The catalytic material in the catalyst holder 24 is thus retained within the housing 10 , with the sidewalls 38 , 40 at least at both ends of the catalyst holder 24 meeting the sidewall portions 1 of the housing 10 .
6 and 18, forming spaces 52 and 54 (FIG. 6) between them, respectively.

The upward recess, the downward recess, and the flange portion are
In this way, together with the porous portion of the retainer 24,
The exhaust gas introduced into the gas inlet is transferred to the catalyst holder 2.
It passes through a catalyst 48 housed in 4.

In a preferred form, the exhaust gas inlet cylinder 56 is displaced slightly upward relative to the axial direction of the catalytic converter, while the exhaust gas outlet cylinder 58 is displaced slightly downward to smooth the gas flow. It's becoming like that. The angle of displacement between the exhaust gas inlet cylinder 56 and the outlet cylinder 58 may vary depending on the position of the catalytic converter within the exhaust system.

With this configuration, an exhaust gas inlet cylindrical portion 5 is provided in the housing 10 as shown in FIGS. 6 and 7.
An inlet plenum 76 is formed in communication with 6 and includes a space 52 extending around the top retainer member 26 . Similarly, an outlet fill chamber 78 is formed within the housing 10 that communicates with the exhaust gas outlet barrel 58 and includes a space 54 that extends around the bottom retainer member 28 .

The catalytic converter described above has an inclined catalytic bed which is connected to the inlet cylinder 56 as shown in FIG.
from the inlet to the outlet cylindrical portion 58 so that exhaust gas entering the catalytic converter from the inlet is directed from the inlet plenum 76 to both retainer members 26, 28 and the catalytic material 48 held therein. It should pass through and pass downward. In general, the lower part of the passenger compartment of a car is lower than the lower part of the trunk, and considering that a small depth is required to avoid collisions with obstacles on the road, the above-mentioned sloping Because the catalyst bed has a relatively shallow depth but a relatively large volume, its height is relatively small compared to its length, so it can be placed on the vehicle at a location in the exhaust gas system relatively close to the engine. A catalytic converter is formed that is easy to install and is effective because it ensures rapid warm-up of the catalytic converter compared to a catalytic converter that must be placed in a conventional exhaust muffler location. It is capable of treating exhaust gas (satisfying exhaust gas regulation standards). The slanted catalyst bed and downward flow of exhaust gas ensure an even flow distribution of exhaust gas within the catalytic converter while minimizing fluidization and movement of catalyst particles. Although the catalytic converter has been described above as having exhaust gas flowing downwardly from the inlet to the outlet through an upwardly sloping catalytic bed,
The gas flow may be reversed so that the exhaust gas flows upwardly through the downwardly sloping bed from the inlet to the outlet.

As shown in FIGS. 5-10, the top housing member 12 and the bottom housing member 14 are formed with a plurality of recesses 80 through which openings 82 extend, the recesses having corresponding openings 83. It abuts the top and bottom retainer members 26, 28 (FIG. 10). The support stud 84 is attached to the catalyst holder 2
4, the catalyst 48 passes through the opening 83 in the catalyst holder 24 and the opening 82 in the recess 80 of the housing 10. Each end of the stud 84 is formed with a shoulder 86 upon which the top and bottom porous portions 30, 34 of both retainer members 26, 28 are seated. Openings 82 are located in the top and bottom housing members 1
It is surrounded by an annular lip portion 88 extending outwardly from 2,14. The lip portion 88 is bored to provide a relatively loose fit between it and the stud 84, the lip portion 88 is welded to the stud 84, and a recess around the annular lip portion 88 is then formed. A reinforcing washer 90 is fitted within 80 and secured by a continuous annular weld 94 (FIG. 9), thereby welding the members together.
The use of studs and reinforcing washers significantly strengthens the housing 10 and catalyst retainer, resulting in a structure with high strength and resistance to deformation even at elevated temperatures and pressures. As shown in another embodiment of the invention illustrated in FIGS. 2 and 3, the top and bottom pores 30, 34 of the retainer members 26, 28 optionally include stiffening ribs 96. may be formed. However, the sagging of the catalyst holder 24 and the obstruction of the exhaust gas flow at high temperatures can be avoided by using the armored window 3 without using the ribs, as shown in FIG.
It has been found that it can also be reduced by reducing the number of 2'.

A top cover 98 is provided above the top housing member 12 and therebetween is a material such as ceramic wool, for example, to protect the catalytic converter from heat loss and to protect the lower body of the vehicle from the heat of the catalytic converter. A thermal insulation layer 100 is interposed. Similarly, a bottom cover 99 is provided below the bottom housing member 14 with another thermally insulating layer between the bottom housing member 14 and the bottom cover 99 to reduce heat loss through the bottom of the catalytic converter. 101 is interposed. The top cover 98 is provided with a U-shaped flange 102 and the bottom cover 99 is provided with a flange portion 97, which U-shaped flange 102 is provided with an edge-sealed flange portion 20, 22 of the housing 10.
and crimped over flange portion 97 of bottom cover 99, thereby securing top and bottom covers 98, 99 to housing 10 accordingly. Top cover 98 also includes ribs 103 to increase its rigidity.

In manufacturing and assembling the catalytic converter described above, the top housing member 12 and the bottom housing member 14 of the housing 10 are formed as substantially identical stampings, which include the recess 80 and its through opening 82.
and can be made by a single die-forming operation. Since both parts are substantially identical, they may be suitably formed using similar dies, making it possible to produce and store the parts economically. Similarly, both cage members 26, 28 may be formed from the same die, in which case both cage members are interchangeable during assembly. If desired, prior to assembly, one of the housing members 12, 14 and the proximal retainer member and one of the covers 98, 99 may have cutouts 104, 105, 107, respectively, in the side walls, as shown in FIG. may be provided to allow probes to be passed through these holes to monitor the temperature of the catalyst bed or its activity after assembly.
In a preferred embodiment of the invention, this point is
This is the only point in which these members differ from each other.

Then the four members 12, 14 and 26, 28
When assembled through the stud 84 and set in the mounting device, the surfaces 20', 2 of the flange portion
2', 42', and 44' abut to form a four layer sandwich trench, which is then sealed with a single, generally continuous peripheral weld to its outer periphery to provide an internal and external seal.

The welding sequence is preferably automatic, with the parts standing sideways on a mounting device with their periphery exposed facing a vertically mounted electron beam welder, and turning the parts to produce a nearly continuous welding process. A weld is formed.

Washer 90 is then placed in position and secured to stud 84 and lip portion 88 by weld 94 of lip portion 88, preferably using an electron beam welding operation.

The inlet and outlet cylindrical members 60, 62 of the exhaust system are then inserted into the inlet cylindrical section 56 and the outlet cylindrical section 58 of the converter, respectively, and continuous peripheral welding is then performed (106, FIG. 4) to remove the inlet cylindrical sections. 56
, the inlet side cylindrical member 60 is directly connected to each of the top housing member 12, top retainer member 26, bottom retainer member 28, and bottom housing member 14 by welding (left end in FIG. 6),
On the other hand, in the outlet cylindrical portion 58, the outlet side cylindrical member 6
2 are welded directly to each of the bottom housing member 14, top retainer member 26, bottom retainer member 28, and top housing member 12 (far right in FIG. 6). Thereby, the top holder member 26 and the bottom holder member 28 constitute the catalyst holder 24, which is continuously welded and connected along the entire circumference thereof.

Finally, the catalyst substance 48 is introduced into the catalyst housing portion 46 of the catalyst holder 24 through the filling hole 108 (FIGS. 6 and 12), and the threaded bush 10 is inserted into the filling hole.
9 is fixed by welding. Preferably, the catalytic converter is vibrated during the filling operation to ensure that the material therein is completely packed. Next, if the removable plug 110 is screwed into the bush, even when the catalytic converter is installed in an automobile, the catalyst can be replaced by providing the plug at the bottom of the catalytic converter.

Next, insulation layers 100 and 1 are formed on the top and bottom of the housing 10.
01, the U-shaped flange portion 102 of the top cover 98 may be crimped around the periphery of the weld 50 and the flange portion 97 of the bottom cover 99.

In operation, gas from the internal combustion engine is conveyed by the inlet cylindrical member 60 into the inlet cylindrical portion 56 and into the inlet plenum 76, and after sealing the top retainer member 26 of the catalyst retainer 24, the gas is transferred to the catalyst retainer 24. It flows downwardly through the openings 32 in the top porous portion 30 of the vessel 24 and across the catalyst material 48 in which the oxidation and/or reduction reactions occur. The treated gas exits through the opening 36 in the bottom porous portion 34 of the catalyst retainer 24 and is collected in the outlet plenum 78, and the treated gas then flows from the outlet barrel 58 to the outlet cylindrical member 62 and the tail of the exhaust system. Exhausted into the atmosphere via pipes.

The embodiment of the invention shown in FIGS. 1-3 is similar to the embodiment shown in FIGS. 4-12, but without the bottom cover plate and thermal insulation layer, which is pressed into the catalyst retainer. 1-2, and the exhaust gas inlet edge of the bottom retainer member does not extend to the exhaust gas inlet edges of the top retainer member and the bottom housing member. First, in this embodiment, the bottom retainer member is attached to the top retainer member by being narrowed by the top retainer member and the bottom housing member near its exhaust gas inlet edge; The exhaust gas outlet edge of the top retainer member does not reach the exhaust gas outlet edges of the bottom retainer member and the top housing member, and in this embodiment the top retainer member has a bottom retainer near its exhaust gas outlet edge. The two layers are each welded to the cylindrical member of the exhaust system at the lower left and upper right in FIG. be done. That is, only the top retainer member 26 has an upward recess that is directly connected to the inlet cylindrical member 60 of the exhaust system, and the bottom retainer member has a downward recess that is directly connected to the outlet cylindrical member 62 of the exhaust system. Only 28 have it. Also, the exhaust gas inlet edge of the flange portion of the bottom retainer member does not reach the exhaust gas inlet edge of the flange portion of the top retainer member and the bottom housing member, and the exhaust gas outlet edge of the flange portion of the top retainer member The part also does not reach the exhaust gas outlet edge of the flanged part of the bottom retainer member and the top housing part, so that on the inlet side only the flange part of the top retainer member and on the outlet side only the flange part of the bottom retainer member Only the flange portion of the vessel member is narrowed by the flange portions of the top and bottom housing members. In this case, the top and bottom cage members are not continuously welded to each other at the exhaust gas inlet and outlet edges, but even if a gas leak were to occur in these areas, the leak would quickly circulate the catalyst. There is no problem because it does not. This embodiment is the same as the embodiment shown in FIGS. 4 to 12 except for the other points and the points specially noted in the description of the embodiment shown in FIGS. 4 to 12.

The effects of the present invention will be explained below.

First, the converter of the present invention solves the following problems.

(1) Supporting the catalyst retainer more firmly within the housing (2) Connecting the retainer and both housing members directly to the exhaust system. This promotes a strong support, and since there is no league to speed up the catalyst, it is possible to reliably separate the harmful exhaust gases at the inlet from the clean exhaust gases at the outlet.

That is, (1) as described in the claims, the top retainer member has an upwardly recessed portion extending from one end of its side wall portion toward the inlet channel in a non-porous state; The upwardly recessed portion of the member further extends axially in an unperforated manner along the inlet half-cylinder of the bottom housing member and forms an exhaust gas inlet barrel with the inlet half-cylinder of the top housing member for top retention. The upwardly recessed portion of the retainer member and the inlet semi-cylindrical portion of the top housing member are directly connected to the inlet side cylindrical member of the exhaust system, and the bottom retainer member is connected from one end of the side wall portion toward the inlet flow path. an extending upwardly recessed portion of the bottom retainer member, the upwardly extending recessed portion of the bottom retainer member further extending axially in a non-porous manner along and overlapping an inlet half-cylinder portion of the bottom housing member; and is sandwiched between the further axially extending upwardly recessed portion of the top retainer member and the inlet semi-cylindrical portion of the bottom housing member, and the bottom retainer member is held at the other end of the side wall portion thereof. a downwardly directed recess extending imperforately from the bottom toward the outlet flow path, the downwardly directed recess in the bottom retainer member being further axially imperforate along the outlet semi-cylindrical portion of the top housing member; and together with the outlet semi-cylindrical portion of the bottom housing member form an exhaust gas outlet cylindrical portion such that the downward recess of the bottom retainer member and the outlet semi-cylindrical portion of the bottom housing member form an exhaust gas outlet cylindrical portion of the exhaust system. be connected directly,
The top retainer member has a downwardly directed recess extending from the other end of the sidewall toward the outlet flow passage, the downwardly recessed portion of the top retainer member further extending axially into the outlet semi-cylinder of the top housing member. extending along the section and overlapping the outlet semi-cylindrical section and sandwiched by the further axially extending downwardly recessed section of the bottom retainer member and the exit semi-cylindrical section of the top housing member. and the periphery of the top and bottom housing members is integrally provided with a housing flange portion over the entire periphery except the exhaust gas inlet and outlet edges; and the periphery of the top and bottom retainer members is integrally provided. The flange portion of the catalyst holder is integrally provided over the entire periphery except for the exhaust gas inlet edge and outlet edge, and the flange portion provided on the periphery of both holder members is connected to the periphery of both housing members. It is clamped by a flange section provided on the. This advantage is extremely important. Namely: (i) Being strong is an important requirement for the converter to be self-supporting and properly supported within the exhaust system. This is because the inlet of the converter moves with the vibrations of the engine relative to the vehicle frame, to which the outlet of the converter is directly connected. The catalytic converter is self-supporting in that the catalyst retainer is connected directly to one of the cylindrical members of the exhaust system by welding, and each housing member is connected directly to one of the cylindrical members of the exhaust system by welding. It can be grown. This results in high rigidity of the exhaust system and high durability of the self-supporting catalyst holder itself.

(ii) The stiffness of the self-supporting catalytic converter is improved by the retainer reinforcing the housing and preventing housing failure due to relative movement between the engine and the vehicle frame. This housing reinforcement is achieved by the fact that each top and bottom housing member has an extension that is directly connected to an extension of the catalyst retainer and where the transducer is connected to the cylindrical member of the exhaust system. achieved. The extensions of the catalyst retainer overlap and extend axially at each end with respective extensions of the housing member, which are connected at each end directly by welding to the cylindrical member of the exhaust system. The rigidity is further strengthened by this.

According to the invention, firstly, a transducer with a low profile and a relatively shallow depth is obtained. That is, (1) as shown in the claims, the top and bottom retainer members each have a substantially uniform depth and a catalyst housing that slopes upwardly from the exhaust gas inlet to the exhaust gas outlet; form a section. This advantage is extremely important. This is because this converter is designed to be mounted on the underside of a passenger car. That is, since the bottom of the passenger area is lower than the bottom of the trunk, a shallow transducer is required to avoid hitting obstacles on the ground. The catalyst retainer of the present invention is simply formed by assembling four members: top and bottom retainer members and top and bottom housing members. This combination provides a relatively high capacity catalyst bed at a relatively shallow depth, and the transducer housing is configured with a relatively low height relative to its length, allowing the transducer to be placed relatively close to the engine. It can be easily installed in the vehicle at the desired location in the exhaust gas system to provide effective exhaust gas warm-up compared to catalytic converters, which normally have to be placed in the exhaust muffler area. Can be processed. Third, the converter of the present invention provides a uniform pressure gradient and reduced resistance to gas flow due to the slightly sloped catalyst bed. That is, (1) as shown in the claims, the depths of the side wall portions of the top and bottom retainer members increase and decrease, respectively, from the exhaust gas inlet to the outlet.

This advantage is important. This is because the flow of gas through the catalyst bed is nearly uniformly distributed for maximum catalyst life and optimum catalytic conversion.
The top and bottom retainer members define slightly sloping catalyst receptacles of substantially uniform depth with varying spacing from the top and bottom housing members. The spacing between the top retainer member and the top housing portion decreases progressively from the exhaust gas inlet to the outlet, creating a progressively decreasing cross-section and a substantially constant pressure gradient for the incoming exhaust gas flow.
Similarly, the spacing between the bottom retainer member and the bottom housing member increases progressively from the gas inlet to the outlet, creating a progressively increasing cross-section for the incoming exhaust gas flow, imparting a substantially constant pressure gradient. . Reducing the resistance to gas flow is also achieved by extending retainer structures at the inlet and outlet sections that define the flow of gas into and out of the protector. The structure of this catalytic converter creates a streamlined gas flow and facilitates the inflow and outflow of flowing exhaust gas. In the present invention, these effects are as follows.
This is achieved by the side walls of the top and bottom retainer members increasing and decreasing in depth, respectively, from the exhaust gas inlet to the outlet.

Fourth, in the converter of the present invention, there is no leakage that would quickly dislodge the catalyst housed in the slightly inclined catalyst housing. That is, (1) As shown in the claims, the top retainer member has an upwardly recessed portion extending in a non-porous state from one end of the side wall portion toward the inlet flow path; The upwardly directed recess further extends axially in a nonporous manner along the inlet half-cylinder of the bottom housing member and forms an exhaust gas inlet barrel with the inlet half-cylinder of the top housing member. The upward recess and the inlet semi-cylindrical portion of the top housing member are directly connected to the inlet cylindrical member of the exhaust system, and the bottom retainer member is connected directly to the inlet cylindrical member of the exhaust system from the other end of the side wall thereof toward the outlet flow path. a downwardly extending recess in the bottom retainer member, the downwardly facing recess in the bottom retainer member extending further axially in a nonporous manner along the exit semi-cylindrical portion of the top housing member; together with the outlet semi-cylindrical part, an exhaust gas outlet cylinder is formed such that the downward recess of the bottom retainer member and the outlet semi-cylindrical part of the bottom housing member are directly connected to the outlet cylinder of the exhaust system; A flange portion is integrally provided on the periphery of the bottom cage member over the entire periphery except for the exhaust gas inlet edge and the outlet edge. Both housing members are clamped by flanges provided at their peripheral edges.

(2) as described in the claims, the top and bottom retainer members define a substantially uniform depth sloped catalyst receptacle that slopes upwardly from the exhaust gas inlet to the exhaust gas outlet; The sidewall portions of the top and bottom retainer members have depths that increase and decrease, respectively, from the exhaust gas inlet to the outlet.

This advantage is extremely important. (i) If a catalyst fast leak occurs around the catalyst retainer, harmful untreated gases will be released into the atmosphere, and (ii) the absence of a catalyst fast leak will reduce the lifetime of the converter. Extend.

The present invention also has novel and important features. The holder extends upstream beyond the catalyst accommodating part under the inflowing exhaust gas, without thereby reducing the catalyst accommodating space; The structure extends in the downstream direction without any holes, thereby not reducing the catalyst accommodating portion, thus maintaining a sufficient effective volume of the catalyst holding space, and without leaking the exhaust gas through the catalyst. be.

(A) The extended section has (1) appropriate catalyst capacity, (2) combined with the flange section to ensure that exhaust gas flows into the gas inlet and passes through the catalyst, and (3) avoids the inevitable temperature gradients and sudden changes in the catalytic converter. To provide an extremely robust device that can sufficiently withstand thermal stress caused by severe temperature changes.

(B) The top and bottom retainer members (1) in combination with the top and bottom housing members provide a slightly sloped catalyst housing, and (2) each increase in depth from the exhaust gas inlet to the outlet. and a decreasing sidewall portion which cooperates with said extension portion to facilitate entry into and exit from the transducer. This feature is
Reduce resistance to gas inflow.

Since the catalytic converter according to the invention can be manufactured by simply assembling four main parts in its final assembly stage, the number of connections and therefore the number of seams can be reduced to a minimum. This reduces the possibility of wear-and-tear damage and the possibility of leaks that can rapidly deactivate the catalyst. Additionally, the simple construction and design reduces steel usage and reduces warm-up time to warm up the catalyst and reach effective operating temperatures.
However, the simple structure reduces the possibility of errors in mass production.

As described above, the present invention relates to the invention described in the claims, and may further have one or more of the following features in practice.

(1) Each retaining member shall consist of a single unitary piece of material.

(2) The perforated part of the cage is a part of the cage that is press-formed into an arc shape.

(3) A top cover that rests on the top housing member has a peripheral flange that is crimped onto the sealed peripheral ends of the housing member and retainer member, and the layer 100 of thermally insulating material is attached to the top cover and the housing member. placed between.

(4) A bottom cover is attached to the bottom housing member and a layer of thermally insulating material is disposed between the bottom housing member and the bottom cover.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional side view (-cross-sectional view in FIG. 2) of an embodiment of a catalytic converter according to the present invention;
The drawing is a reduced plan view of Fig. 1 with a part cut away to show the internal structure, Fig. 3 is a sectional view taken along the - line in Fig. 1, and Fig. 4 is another view of the catalytic converter according to the present invention. FIG. 5 is a side view of the preferred embodiment; FIG. 5 is a plan view of FIG. 4, with a portion cut away to show the internal structure;
Figure 6 is a sectional view taken along the - line in Figure 5;
The figure is a sectional view taken along the - line in Fig. 4, Fig. 8 is an enlarged fragmentary sectional view taken along the - line in Fig. 5, and Fig. 9 is an enlarged plan view of a part of Fig. 5, showing a part of the internal welding. FIG. 10 is a sectional view taken along the - line in FIG. 9, FIG. 11 is an enlarged fragmentary side view taken along the line XI--XI in FIG. 5, and FIG.
1 is an exploded perspective view of the illustrated catalytic converter embodiment; FIG. [Explanation of reference symbols of main parts], 10... Housing, 12, 14... Top and bottom housing members, 24... Catalyst retainer, 26, 28... Top and bottom retainer members, 30, 34... Porous top and bottom, 46...catalyst housing part, 48...catalyst material, 56...exhaust gas inlet cylindrical part, 58...
Exhaust gas outlet cylindrical part, 64... Semi-cylindrical part of top housing member, 66... Semi-cylindrical part of bottom housing member, 60... Inlet side cylindrical member of exhaust system, 6
2...Exhaust system outlet side cylindrical member, 20, 22...
...Flange portion of the housing, 42, 44...Flange portion of the catalyst holder.

Claims (1)

Claims: 1. Exhaust gas flows past a catalyst contained within a catalyst retainer within a housing; the housing has top and bottom housing members, each housing member having a dish-shaped portion. said plate-shaped portions surround said catalyst retainer; said plate-shaped portions have a semi-cylindrical portion for forming a cylindrical exhaust gas inlet flow path and an outlet flow path; and an outlet flow path are each arranged axially spaced from a catalyst receiving portion of the catalyst holder; the catalyst receiving portion of the catalyst holder has top and bottom porous portions forming an exhaust gas passage through the catalyst. and further comprising: an exhaust gas catalytic converter for an internal combustion engine, wherein the catalyst retainer has a flange portion sandwiched between flange portions extending around a periphery of a housing member; formed by vessel members 26, 28; the top and bottom cage members each have sidewalls that together with the top and bottom pores form the catalyst housing; the top cage member has sidewalls thereof; the upper retainer member has an upwardly extending recess extending imperforately from one end of the portion toward the inlet flow path; The top housing member 1 extends axially in a non-perforated manner.
The exhaust gas inlet cylindrical portion 56 is formed together with the inlet semi-cylindrical portion 64 of No. 2 so that the upwardly recessed portion of the top retainer member and the inlet semi-cylindrical portion of the top housing member are directly connected to the inlet side cylindrical member of the exhaust system. the bottom retainer member has an upwardly recessed portion extending from one end of the side wall portion toward the inlet channel; the upwardly recessed portion of the bottom retainer member further extends axially toward the inlet of the bottom housing member; a portion of the further axially extending upwardly recessed portion of the top retainer member and an inlet semi-cylinder portion of the bottom housing member extending along and overlapping the inlet half-cylinder portion 66; the bottom retainer member has a downward recess extending in a non-porous manner from the other end of the side wall toward the outlet flow path; The facing recess extends axially further along the outlet semi-cylindrical portion 64 of the top housing member 12 and in a non-porous manner
The exhaust gas outlet cylindrical portion 58 is formed together with the outlet semi-cylindrical portion 66 of 4 so that the downward recess of the bottom retainer member and the outlet semi-cylindrical portion of the bottom housing member are directly connected to the outlet side cylindrical member of the exhaust system. the top retainer member has a downwardly recessed portion extending from the other end of the side wall portion toward the outlet flow passage; the downwardly directed recessed portion of the top retainer member further extends axially into the top housing member; a portion of the further axially extending downwardly recessed portion of the bottom retainer member and an exit half-cylinder portion of the top housing member extending along and overlapping the outlet half-cylinder portion 64; The inlet semi-cylindrical part, the dish-shaped part, and the outlet semi-cylindrical part constituting the top and bottom housing members are each integrally formed of the same material; and the peripheral edges of the top and bottom housing members a flange portion of the housing is integrally provided on the entire periphery except for the exhaust gas inlet edge and the outlet edge;
Further, the flange portion of the catalyst retainer is integrally provided on the entire peripheral edge of the top and bottom retainer members except for the exhaust gas inlet edge and the outlet edge, and the flange portion of the catalyst retainer is integrally provided on the entire peripheral edge of the top and bottom retainer members, flange portions provided on the housing members are clamped by flange portions provided on the peripheral edges of both housing members; and the sidewall portions of the top and bottom retainer members each have a depth from exhaust gas inlet 56 to exhaust gas outlet 58; An exhaust gas catalytic converter for an internal combustion engine characterized by increasing and decreasing exhaust gas.