JPH1182004A - Exhaust emission purifying device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent an exhaust passage from being partially blocked by particulates by providing an exhaust passage subdivided by a plurality of bulkhead extended in exhaust gas flowing direction, and longitudinally arranging the end surfaces of adjacent two bulkheads in the exhaust gas flowing direction in the exhaust upstream side part. SOLUTION: A layered catalytic converter has a flat plate 1(1') and a corrugated plate 2 as bulkheads, and a catalyst is supported by the flat plate 1 and the corrugated plate 2. The flat plate 1 and the corrugated plate 2 are spirally wound in layer and housed in a cylindrical case 3, and an exhaust passage is subdivided by the flat plate 1 and the corrugated plate 2 in exhaust gas flowing direction. The flat plate 1' is protruded on the exhaust upstream side to the corrugated plate 2 to longitudinally arrange the end surfaces of the flat plate 1' and the corrugated plate 2 in the exhaust gas flowing direction, whereby the end surfaces are prevented front being mutually fitted in the collecting part of the flat plate 1' and the corrugated plate 2 to form a relatively large area part, so that the exhaust passage of a catalytic converter is prevented from being blocked by particulates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exhaust gas purification device for an internal combustion engine.

[0002]

The exhaust system of an internal combustion engine, HC contained in the exhaust gas, CO, and catalytic converter for harmful substances by converting into harmless substances purifying exhaust gas of the NO _x or the like is arranged ing. In such a catalytic converter, an exhaust passage is generally subdivided by a plurality of partition walls extending in the exhaust gas flow direction. As a result, the exhaust gas comes into contact with the partition walls having a very large surface area as a whole, so that the catalyst supported on the partition walls achieves good purification of the exhaust gas.

[0003] In addition to the above-mentioned harmful substances, the exhaust gas of an internal combustion engine, particularly a diesel engine, contains a relatively large amount of exhaust particulates (particulates) mainly composed of carbon. Most of these particulates are
It passes through the subdivided exhaust passage of the catalytic converter,
Part of it adheres to the end face of the partition wall of the catalytic converter and gradually accumulates.

[0004]

In a general catalytic converter, there is a portion where the area of the end face is relatively large in a gathering portion of a plurality of partition walls, and a large amount of particulates accumulates in this portion, and finally, the catalyst A portion of the converter's fragmented exhaust passage is closed by particulates, which can significantly increase exhaust resistance.

Accordingly, an object of the present invention is to provide an exhaust gas purifying apparatus for an internal combustion engine having an exhaust passage subdivided by a plurality of partitions extending in the exhaust gas flow direction, wherein a part of the exhaust passage is closed by particulates. It is to prevent that.

[0006]

According to a first aspect of the present invention, there is provided an exhaust gas purifying apparatus for an internal combustion engine having an exhaust passage subdivided by a plurality of partitions extending in an exhaust gas flow direction. At least the exhaust upstream portion of the purification device is
The end faces of two adjacent partition walls are arranged back and forth in the exhaust gas flow direction.

According to a second aspect of the present invention, there is provided an exhaust gas purifying apparatus for an internal combustion engine having an exhaust passage subdivided by a plurality of partitions extending in an exhaust gas flow direction, wherein the plurality of partitions are flat plates. And the corrugated plate, wherein the flat plate and the corrugated plate are alternately laminated, or the flat plate and the corrugated plate are spirally wound, whereby the exhaust passage is subdivided. In the exhaust emission control device, at least an exhaust upstream side portion of the exhaust emission control device is configured such that all the curved portions of the corrugated sheet located on both sides of the flat plate do not face each other.

According to a third aspect of the present invention, there is provided an exhaust gas purifying apparatus for an internal combustion engine having an exhaust passage segmented by a plurality of partitions extending in an exhaust gas flow direction, wherein the plurality of partitions intersect. In the exhaust gas purifying apparatus for an internal combustion engine, wherein the exhaust passage is subdivided into a rectangular cross section, at least an exhaust upstream side portion of the exhaust gas purifying apparatus is characterized in that the partition walls intersect in a substantially T-shape. I do.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view of a general stacked catalytic converter viewed from an exhaust gas upstream side. This stacked catalytic converter has a flat plate 1 and a corrugated plate 2 made of heat-resistant metal as partition walls, and the flat plate 1 and the corrugated plate 2 carry a catalyst for purifying harmful components in exhaust gas. ing.
The flat plate 1 and the corrugated plate 2 are overlapped and spirally wound, housed in a cylindrical case 3, and the exhaust passage is subdivided in the exhaust gas flow direction by the flat plate 1 and the corrugated plate 2. Thereby,
The exhaust gas comes into contact with a very large surface area of the flat plate 1 and the corrugated plate 2 as a whole, and is well purified by the catalyst carried on the flat plate 1 and the corrugated plate 2.

However, in such a general stacked type catalytic converter, as shown in a position A, in the gathering portion of the flat plate 1 and the corrugated plate 2 functioning as partition walls, the curvature of the corrugated plate 2 located on both sides of the flat plate 1 is Since the portions 2a face each other, there are a plurality of portions where the area of the end face is relatively large in part. As a result, a large amount of particulates contained in the exhaust gas accumulate in this portion. The particulates deposited in this way grow in the transverse direction of the catalytic converter without collapsing because the root portion is large and firmly attached to the end face of the catalytic converter, and finally, the finely divided exhaust passage of the catalytic converter May be closed by particulates.

FIG. 2 is a partially enlarged view of a stacked catalytic converter as a first embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention, as viewed from the exhaust upstream side. As shown in the figure, in the present laminated catalytic converter, the wave width B of the corrugated sheet 2 ′ is wider toward the outside of the catalytic converter, and thus, unlike a general laminated catalytic converter, both sides of the flat plate 1 are different. The curved portions 2a 'of the corrugated plate 2' are all not opposed to each other. Thereby, the area of the end face in the gathering part of the flat plate 1 and the corrugated plate 2 'is made relatively small,
Even if particulates accumulate in this portion, the root portion is small, so that it collapses before growing in the transverse direction of the catalytic converter, and the particulate exhaust passage of the catalytic converter is not closed by the particulates.

Of course, in the present embodiment, it is only necessary that all the curved portions 2a 'of the corrugated sheet 2' located on both sides of the flat plate 1 do not face each other. To this end, the wave width of the corrugated sheet 2 'is reduced. The width is not limited to be wider toward the outside of the catalytic converter. For example, instead of increasing the wave width of the corrugated sheet 2 ′ at the outer portion of the catalytic converter, the width may be reduced to about １ ／.

FIG. 3 is a longitudinal partial sectional view of an exhaust gas upstream side portion of a stacked catalytic converter as a second embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention. As shown in the figure, in the present stacked catalytic converter, the flat plate 1 ′ is a corrugated plate 2.
Projecting upstream of the exhaust gas. FIG. 4 is a longitudinal partial cross-sectional view of an exhaust upstream portion of a stacked catalytic converter as a third embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention. As shown in the figure, in the present laminated catalytic converter, the corrugated plate 2 ″ projects upstream of the flat plate 1 on the exhaust side.

In the second and third embodiments, since the end faces of the flat plate and the corrugated plate are arranged in the exhaust gas upstream side of the catalytic converter in the exhaust gas flow direction, the flat plate and the corrugated plate are combined. The end faces are not combined to form a relatively large area, there is no portion where a large amount of particulates are deposited, and the particulate exhaust passage of the catalytic converter is not closed by the particulates. .

Although the first, second, and third embodiments have been described as a catalytic converter in which a set of flat plates and corrugated plates are spirally wound, the idea in these embodiments is that a plurality of sets of flat plates and corrugated plates are used. The present invention is also applicable to a catalytic converter in which a spiral plate and a corrugated plate are spirally wound. Further, the present invention is also applicable to a catalytic converter in which a plurality of flat plates and corrugated plates are alternately stacked, for example, vertically or horizontally. When the concept of the first embodiment is applied to a catalytic converter in which flat plates and corrugated plates are alternately stacked, it is clear that it is better to keep the wave widths of a plurality of corrugated plates constant without changing them.

FIG. 5 is a view of a general integrated molding type catalytic converter viewed from the upstream side of exhaust gas. The monolithic catalytic converter comprises, for example, a body 4 of porous ceramic material.
And a cylindrical case 5 for housing the main body 4. The main body 4 includes a plurality of vertical partition walls 4a arranged in a grid.
And a plurality of horizontal partitions 4b, and a catalyst is carried on each vertical partition 4a and each horizontal partition 4b. In this way, the exhaust passage is subdivided, and the exhaust gas contacts the very large surface area of the vertical partition 4a and the horizontal partition 4b as a whole, so that the exhaust gas is favorably purified by the catalyst carried on the vertical partition 4a and the horizontal partition 4b. It has become.

In this integrally formed catalytic converter,
The subdivided exhaust passage has a square cross section. When the subdivided exhaust passage has a rectangular cross-sectional shape as described above, it becomes easier to form a mold when the main body is integrally molded, as compared with other cross-sectional shapes. Accordingly, a general integrated molding type catalytic converter has a subdivided exhaust passage having a rectangular cross section.

However, in such a general integrated molding type catalytic converter, the partition walls cross each other at the gathering portion of each vertical partition wall 4a and each horizontal partition wall 4b,
The area of the end face of this gathering portion becomes relatively large. As a result, there is a possibility that a large amount of particulates will adhere to and accumulate on this portion, thereby closing a part of the subdivided exhaust passage of the catalytic converter.

FIG. 6 is a partially enlarged view of an integrally molded catalytic converter as a fourth embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention, as viewed from the exhaust gas upstream side. As shown in FIG.
a and the horizontal partition wall 41b intersect in a substantially T-shape at the gathering portion. As a result, the area of the end face of this assembly is made relatively small, and even if particulates accumulate in this part, the base part is small, so that it collapses before growing in the transverse direction of the catalytic converter, and the catalytic converter is subdivided. The closed exhaust passage will not be closed. The concept of the present embodiment is also effective when the section of the subdivided exhaust passage has another rectangular shape such as a rectangle in the integrally formed catalytic converter.

FIG. 7 is a longitudinal cross-sectional view of an exhaust gas upstream side portion of an integrally molded catalytic converter as a fifth embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention. As shown in the figure, in the present integrally molded catalytic converter, each horizontal partition wall 42b projects upstream of the exhaust gas with respect to each vertical partition wall 42a. FIG. 8 is a longitudinal partial cross-sectional view of an exhaust-gas upstream portion of an integrally molded catalytic converter as a sixth embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention. As shown in the figure, in the present integrally formed catalytic converter, each vertical partition wall 43a projects upstream of the exhaust gas with respect to each horizontal partition wall 43b.

In the fifth and sixth embodiments, the end faces of each vertical partition and each horizontal partition are located in front of and downstream of the catalytic converter in the exhaust gas flow direction. In the collecting part, the end faces do not combine to form a relatively large area, there is no portion where a large amount of particulates are deposited, and the particulate exhaust passage of the catalytic converter is closed by the particulates. Never.

FIG. 9 is a partial longitudinal sectional view of an exhaust upstream side portion of an integrally formed catalytic converter as a seventh embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention. The difference from the fifth embodiment is that the end face of each vertical partition 44a has a corner and is convex. As a result, the particulates adhering and depositing on the end surfaces of the vertical partition walls 44a are liable to break from the corners and collapse, and the deposition of a large amount of particulates can be prevented more reliably.

FIG. 10 is a longitudinal partial cross-sectional view of an exhaust upstream portion of an integrally formed catalytic converter as an eighth embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention. The difference from the above-described sixth embodiment is that the end face of each vertical partition wall 45a has a corner and is convex. Thereby,
The particulates adhering and accumulating on the end face of each vertical partition 45a are easily broken by breaking from the corners, and the accumulation of a large amount of particulates can be prevented more reliably. Of course, in the fifth and sixth embodiments, not only the vertical partition but also the horizontal partition is similarly made convex so that a large amount of particulates can be reliably prevented from adhering to the horizontal partition.

The concept of the fifth, sixth, seventh, and eighth embodiments is not limited to the integrally formed catalytic converter in which the segmented exhaust passage has a rectangular cross-sectional shape as in the fourth embodiment. The present invention is also applicable to an integrally formed catalytic converter having an exhaust passage having a polygonal cross-sectional shape other than a rectangular shape, for example, a hexagonal cross-sectional shape. In such a case, the end faces of the two adjacent partition walls may be moved back and forth in the exhaust gas flow direction, and if necessary, the end faces of the partition walls may have a convex shape having corner portions.

[0025]

As described above, according to the exhaust gas purifying apparatus for an internal combustion engine according to the first aspect of the present invention, the exhaust gas purifying apparatus has an exhaust passage segmented by a plurality of partitions extending in the exhaust gas flow direction. At least the exhaust upstream side portion of the exhaust gas purification device has a large end face of the two partition walls at the gathering portion of the two partition walls because the end faces of the two adjacent partition walls are arranged back and forth in the exhaust gas flow direction. No area is formed. In this way, since there is no portion where a large amount of particulates are deposited, it is possible to prevent a part of the exhaust passage from being closed by the particulates.

According to the exhaust gas purifying apparatus for an internal combustion engine according to the second aspect of the present invention, the exhaust gas purifying apparatus has an exhaust passage divided by a plurality of partitions extending in the exhaust gas flow direction. In an exhaust gas purifying apparatus for an internal combustion engine, which includes a flat plate and a corrugated plate, and the flat plate and the corrugated plate are alternately stacked, or the flat plate and the corrugated plate are spirally wound, so that the exhaust passage is subdivided. At least the exhaust gas upstream side portion of the exhaust gas purification device is configured such that all the curved portions of the corrugated sheet located on both sides of the flat plate do not face each other. As a result, the curved portions of the corrugated sheets located on both sides of the flat plate face each other, and the end faces of the flat plate and the curved portions of the two corrugated plates do not form a large area, and a large amount of particulates is deposited. Due to the absence of such a portion, the particulate prevents the exhaust passage from being partially closed.

According to the third aspect of the present invention, there is provided an exhaust gas purifying apparatus for an internal combustion engine having an exhaust passage segmented by a plurality of partitions extending in an exhaust gas flow direction. In an exhaust gas purifying apparatus for an internal combustion engine in which an exhaust passage intersects and is subdivided into a rectangular cross-sectional shape, at least an exhaust upstream side portion of the exhaust gas purifying apparatus has a substantially T-shaped partition wall. Thereby, in order to form the subdivided exhaust passage having the rectangular cross-sectional shape, the plurality of partition walls do not cross each other to form a large area at the end face. In this way, since there is no portion where a large amount of particulates are deposited, it is possible to prevent a part of the exhaust passage from being closed by the particulates.

[Brief description of the drawings]

FIG. 1 is a view of a general stacked catalytic converter viewed from an exhaust upstream side.

FIG. 2 is a partially enlarged view of the exhaust gas purifying apparatus for an internal combustion engine according to the first embodiment of the present invention, as viewed from the exhaust upstream side of a stacked catalytic converter.

FIG. 3 is an enlarged longitudinal sectional view of an exhaust upstream portion of a stacked catalytic converter showing a second embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention.

FIG. 4 is an enlarged longitudinal sectional view of an exhaust upstream portion of a stacked catalytic converter showing a third embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention.

FIG. 5 is a view of a general integrated molding type catalytic converter viewed from an exhaust upstream side.

FIG. 6 is a partially enlarged view of an integrally-formed catalytic converter according to a fourth embodiment of the present invention, as viewed from the exhaust upstream side of the catalytic converter.

FIG. 7 is an enlarged longitudinal sectional view of an exhaust upstream side portion of an integrally formed catalytic converter showing a fifth embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention.

FIG. 8 is an enlarged longitudinal sectional view of an exhaust upstream portion of an integrally molded catalytic converter showing a sixth embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention.

FIG. 9 is an enlarged longitudinal sectional view of an exhaust upstream portion of an integrally molded catalytic converter showing a seventh embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention.

FIG. 10 shows an eighth embodiment of the exhaust gas purifying apparatus for an internal combustion engine according to the present invention.
FIG. 2 is an enlarged longitudinal sectional view of an exhaust upstream side portion of the integrally molded catalytic converter according to the embodiment.

[Explanation of symbols]

1, 1 'flat plate 2, 2', 2 "corrugated plate 4a, 41a, 42a, 43a, 44a, 45a vertical partition 4b, 41b, 42b, 43b, 44b, 45b horizontal partition

Claims (3)

[Claims] 1. An exhaust purification device comprising an exhaust passage segmented by a plurality of partitions extending in an exhaust gas flow direction, wherein at least an exhaust upstream portion of the exhaust purification device has an end face of two adjacent partitions. An exhaust gas purifying apparatus for an internal combustion engine, wherein the exhaust gas purifying apparatus moves back and forth in an exhaust gas flow direction. 2. An exhaust passage segmented by a plurality of partitions extending in an exhaust gas flow direction, wherein the plurality of partitions include a flat plate and a corrugated plate, wherein the flat plate and the corrugated plate are alternately arranged. By being stacked, or by the flat plate and the corrugated plate being spirally wound, in an exhaust gas purification device of an internal combustion engine in which the exhaust passage is subdivided, at least an exhaust upstream portion of the exhaust gas purification device is The exhaust gas purifying apparatus for an internal combustion engine, wherein all curved portions of the corrugated sheet located on both sides of the flat plate do not face each other. 3. An internal combustion engine having an exhaust passage segmented by a plurality of partitions extending in a direction of exhaust gas flow, wherein the plurality of partitions intersect and the exhaust passage is segmented into a rectangular cross-sectional shape. In the exhaust gas purifying apparatus, at least an exhaust gas upstream side portion of the exhaust gas purifying apparatus has the partition walls crossing in a substantially T shape.