JP2007263003A - Exhaust pipe structure in upstream side of catalytic converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust pipe structure in an upstream side of a catalytic converter capable of preventing drop of conversion ratio and preventing crack of catalyst carrier due to temperature distribution difference by sufficiently utilizing effective section area of the catalyst carrier without causing cost increase. <P>SOLUTION: The exhaust pipe structure in the upstream side of the catalytic converter includes a bent part 21 in an exhaust pipe 2 in the upstream side of the catalytic converter 1 and a straightening part 4 is formed by deforming a part of a downstream-side exhaust pipe of the bent part 21 of the upstream-side exhaust pipe 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an upstream exhaust pipe structure of a catalytic converter.

  A catalytic converter interposed in an exhaust system of an automobile or the like for exhaust gas purification is generally provided at a lower position than the engine, and is substantially perpendicular to the upstream exhaust pipe 102 of the catalytic converter 101 as shown in FIG. Since there is a bent portion 102a that bends in a substantially horizontal direction from the direction, when passing through the bent portion 102a, the main flow of exhaust gas becomes a drift that concentrates downward, and in that state, passes through the diffuser 103 and becomes a catalyst carrier. As a result of partial contact and partial passage of the catalyst carrier, there is a problem that the purification rate is lowered without fully utilizing the effective sectional area of the catalyst carrier.

  There is also a problem that the catalyst carrier may be partially heated, which may cause cracking of the catalyst carrier due to a temperature distribution difference.

Therefore, in order to solve the above-described problems, a catalyst carrier having a plurality of parallel flow paths, the flow paths having a first cell group having a higher density and a second cell group having a lower density. Has been disclosed (for example, refer to Patent Document 1).
JP 2000-97019 A

  However, in the conventional catalytic converter structure, the structure of the catalyst carrier is complicated, which leads to a significant cost increase, and the catalyst carrier is partially heated to prevent cracking of the catalyst carrier due to a temperature distribution difference. There is a problem that can not be.

  The problem to be solved by the present invention is that the catalyst carrier remains the same as the conventional one, while suppressing an increase in cost, the effective cross-sectional area of the catalyst carrier is fully utilized to prevent a reduction in purification rate, and due to a temperature distribution difference. An object of the present invention is to provide an upstream exhaust pipe structure of a catalytic converter that can prevent cracking of a catalyst carrier.

  In order to solve the above problems, the upstream exhaust pipe structure of the catalytic converter according to claim 1 is an upstream exhaust pipe structure of a catalytic converter having a bent portion in the upstream exhaust pipe of the catalytic converter, wherein the upstream exhaust pipe The rectifying unit is formed in the vicinity of the inlet of the catalytic converter on the downstream side of the bent portion in the above.

  In the upstream side exhaust pipe structure of the catalytic converter of the present invention, as described above, the rectification part is formed in the vicinity of the inlet of the catalytic converter on the downstream side of the bent part in the upstream side exhaust pipe. The exhaust gas that has drifted through the bent part flows into the catalytic converter after being rectified by the rectifying part, so that the effective sectional area of the catalyst carrier is fully utilized to reduce the purification rate. In addition to preventing, cracking of the catalyst carrier due to temperature distribution difference can be prevented.

  In addition, since a conventional product composed of a group of cells having the same density can be used as the catalyst carrier, and the rectification unit is formed on the upstream side exhaust pipe, compared to the case where it is formed on the catalytic converter side, It is easy to form, and therefore the cost increase can be greatly suppressed.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the upstream side exhaust pipe structure of the catalytic converter of the first embodiment will be described with reference to the drawings.

  FIG. 1 is a partially cutaway side view showing an upstream side exhaust pipe structure of the catalytic converter of the first embodiment, and FIG. 2 is an enlarged longitudinal sectional view taken along line AA of FIG.

  The upstream exhaust pipe structure of the catalytic converter includes a catalytic converter 1, an upstream exhaust pipe 2, and an output exhaust pipe 3.

  More specifically, the catalytic converter 1 includes a catalyst carrier 11, an outer cylinder 12, and diffusers 13 and 14.

  The catalyst carrier 11 is formed of a ceramic or metal plate in a honeycomb shape having a large number of holes, and a metal catalyst such as Pt, rh, Pd is supported on the surface thereof.

  The outer cylinder 12 forms the outer shape of the catalytic converter by press-fitting the catalyst carrier 11 therein, and the large-diameter opening portions of the diffusers 13 and 14 are connected to the opening edges of both ends by welding, respectively. ing.

  That is, the diffusers 13 and 14 are interposing members for connecting the outer cylinder 12 to the upstream side exhaust pipe 2 and the output side exhaust pipe 3 having a smaller diameter than the catalyst carrier 11, and the small diameter side opening thereof. The upstream side exhaust pipe 2 and the output side exhaust pipe 3 are connected to the part side by welding.

  The upstream exhaust pipe 2 has a bent portion 21 that bends from a substantially vertical direction to a substantially horizontal direction in the middle of the catalytic converter 1 at a position below the engine.

  And the rectification | straightening part 4 is formed in the downstream of the bending part 21 in the upstream exhaust pipe 2. As shown in FIG. That is, the rectifying unit 4 is configured by a flow path cross-sectional portion deformed into a substantially semicircular shape by crushing a part of the upper surface side of the upstream side exhaust pipe 2 downward over a predetermined length. .

  Next, operations and effects of the first embodiment will be described.

  In the upstream side exhaust pipe structure of the catalytic converter of the first embodiment, as described above, the rectifying unit 4 is formed on the downstream side of the bent part 21 in the upstream side exhaust pipe 2, so that the bent part 21. When the exhaust gas that has flowed through the gas flows through the rectifying unit 4 and flows into the catalytic converter 1 in a rectified state after obtaining a change in flow, the effective cross-sectional area of the catalyst carrier 11 is reduced. It is possible to obtain an effect that it is possible to prevent the catalyst carrier 11 from being cracked due to a difference in temperature distribution while being sufficiently utilized to prevent the purification rate from being lowered.

  Moreover, since the conventional product comprised by the cell group of the same density can be used as the catalyst support | carrier 11, and the rectification | straightening part 4 is formed in the upstream exhaust pipe 2, it forms in the catalytic converter 1 side. Compared to the case, the formation is easy, and therefore, the cost increase can be greatly suppressed.

  Next, another embodiment will be described. In the description of the other embodiments, the same components as those of the first embodiment are not shown, or the same reference numerals are given and the description thereof is omitted, and only the differences are described.

The second embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 3 (partially cutaway side view) and FIG. 4 (enlarged longitudinal section along line BB in FIG. 3). As shown in FIG. 2, the flow path deformed into a substantially semicircular shape when the rectifying unit 4 crushes a part of the upper surface side of the upstream side exhaust pipe 2 downward in a substantially V shape in a side view. The present embodiment is different from the above embodiment in that it is configured by a cross-sectional portion.
Therefore, also in the second embodiment, the exhaust gas that has drifted through the bent portion 21 flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

The third embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 5 (partially cutaway side view) and FIG. 6 (enlarged longitudinal section along the line CC in FIG. 5). As shown in FIG. 2, the flow rectifying section 4 is formed into a substantially oblong elliptical cross section by crushing a part of the upper and lower surfaces of the upstream side exhaust pipe 2 downward over a predetermined length. This is different from the above-described embodiment in that it is composed of portions.
Accordingly, also in the third embodiment, the exhaust gas that has flowed through the bent portion 21 and drifted flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

  The fourth embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 7 (partially cutaway side view) and FIG. 8 (enlarged longitudinal section along the line DD in FIG. 7). As shown in the plan view), the rectifying unit 4 is composed of a flow path cross-sectional portion deformed into a petal shape by crushing four places in the circumferential direction of the upstream side exhaust pipe 2 downward over a predetermined length. This is different from the above embodiment.

  Further, the rectifying unit 4 is different from the first embodiment in that the rectifying unit 4 is crushed in a plurality of locations in the groin direction in addition to the exhaust pipe 2 obliquely downward.

  Therefore, also in the fourth embodiment, the exhaust gas that has flowed through the bent portion 21 and drifted flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

The fifth embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 9 (partially cutaway side view) and FIG. 10 (enlarged longitudinal section along line EE in FIG. 9). As shown in FIG. 2, the rectifying unit 4 squeezes the upstream exhaust pipe 2 downward in a circumferential ring shape at a predetermined interval in the axial direction of the upstream exhaust pipe 2 to form a bellows shape. The present embodiment is different from the above-described embodiment in that it is composed of a deformed flow path cross section.
Therefore, also in the fifth embodiment, the exhaust gas that has flowed through the bent portion 21 and drifted flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

The sixth embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 11 (partially cutaway side view) and FIG. 12 (enlarged longitudinal section taken along line FF in FIG. 11). As shown in the plan view), the flow straightening section 4 squeezes the upstream side exhaust pipe 2 downward in the axial direction to form a spiral projecting section projecting inwardly. This is different from the above embodiment in that it is configured.
Therefore, also in the sixth embodiment, the exhaust gas that has flowed through the bent portion 21 and drifted flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

The seventh embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 13 (partially cutaway side view) and FIG. 14 (enlarged longitudinal section along line GG in FIG. 13). As shown in FIG. 2, the rectifying unit 4 is configured by a flow path cross-sectional portion that is formed in a substantially horizontally long ellipse shape by being bent inward in the substantially upper half of the pipe end opening of the upstream side exhaust pipe 2. This is different from the above-described embodiment.
Therefore, also in the seventh embodiment, the exhaust gas that has flowed through the bent portion 21 and drifted flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

The eighth embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 15 (partially cutaway side view) and FIG. 16 (enlarged longitudinal section along line HH in FIG. 15). As shown in the plan view), the rectifying unit 4 is constituted by a flow path cross-sectional portion that is reduced in diameter by narrowing the pipe end opening edge of the upstream side exhaust pipe 2 to the inner side. It is different.
Accordingly, also in the eighth embodiment, the exhaust gas that has flowed through the bent portion 21 and drifted flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

The ninth embodiment shows a modification of the upstream side exhaust pipe structure of the catalytic converter in the first embodiment. FIG. 17 (partially cutaway side view) and FIG. 18 (enlarged longitudinal section along line JJ in FIG. 17). As shown in FIG. 2, the rectifying unit 4 is configured by a flow path cross-sectional portion expanded in diameter by inflating a part of the upstream exhaust pipe 2 into a substantially spherical shape. Is different.
Therefore, also in the ninth embodiment, the exhaust gas that has flowed through the bent portion 21 and drifted flows into the catalytic converter 1 in a rectified state by obtaining a change in flow when passing through the rectifying portion 4. Therefore, the same effect as in the first embodiment can be obtained.

  Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.

1 is a partially cutaway side view showing an upstream side exhaust pipe structure of the catalytic converter of the first embodiment, and FIG. 2 is an enlarged longitudinal sectional view taken along line AA of FIG.
1 is a partially cutaway side view showing an upstream side exhaust pipe structure of a catalytic converter of Example 1. FIG. FIG. 2 is an enlarged longitudinal sectional view taken along the line in FIG. 1. 6 is a partially cutaway side view showing an upstream side exhaust pipe structure of the catalytic converter of Example 2. FIG. FIG. 4 is an enlarged longitudinal sectional view taken along line BB in FIG. 3. It is a partially notched side view which shows the upstream exhaust pipe structure of the catalytic converter of an Example. FIG. 6 is an enlarged longitudinal sectional view taken along line CC in FIG. 5. 6 is a partially cutaway side view showing an upstream side exhaust pipe structure of a catalytic converter of Example 4. FIG. FIG. 8 is an enlarged longitudinal sectional view taken along line DD in FIG. 7. 6 is a partially cutaway side view showing an upstream side exhaust pipe structure of a catalytic converter of Example 5. FIG. FIG. 10 is an enlarged vertical sectional view taken along line EE in FIG. 9. FIG. 10 is a partially cutaway side view showing an upstream side exhaust pipe structure of a catalytic converter according to a sixth embodiment. It is an expanded longitudinal cross-sectional view in the FF line of FIG. FIG. 10 is a partially cutaway side view showing an upstream side exhaust pipe structure of a catalytic converter of Example 7. It is an expanded vertical sectional view in the GG line of FIG. FIG. 10 is a partially cutaway side view showing an upstream side exhaust pipe structure of a catalytic converter according to an eighth embodiment. FIG. 16 is an enlarged longitudinal sectional view taken along line HH in FIG. 15. FIG. 10 is a partially cutaway side view showing an upstream side exhaust pipe structure of a catalytic converter of Example 9. It is an enlarged vertical sectional view in the JJ line of FIG. It is sectional drawing which shows the upstream exhaust pipe structure of the catalytic converter of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Catalytic converter 11 Catalyst carrier 12 Outer cylinder 13 Diffuser 14 Diffuser 2 Upstream exhaust pipe 21 Bending part 3 Output side exhaust pipe 4 Rectification part

Claims (1)

The upstream exhaust pipe structure of the catalytic converter having a bent portion in the upstream exhaust pipe of the catalytic converter,
An upstream exhaust pipe structure for a catalytic converter, characterized in that a rectifying section is formed in the vicinity of the inlet of the catalytic converter on the downstream side of the bent section in the upstream exhaust pipe.

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