Title of Invention

"EXHAUST EMISSION CONTROL APPARATUS FOR INTERNAL COMBUSTION ENGINE"

Abstract [CONSTITUTION] An exhaust emission control apparatus for an internal combustion engine characterized in that a thin steel plate 22 which carries a catalytic metal is disposed at a substantially central portion of the cross section of an exhaust pipe 5 which extends from an exhaust port of the internal combustion engine. [EFFECT] Since the catalytic metal is disposed at the substantially central portion of the cross section at which the temperature of exhaust gas is high, a purification action can be exhibited sufficiently, and besides the cost can be reduced. [SELECTED FIGURE] FIG. 5
Full Text The present invention relates to an exhaust emission control apparatus for an internal combustion engine.
[Prior Art]
Conventionally, as an exhaust emission control apparatus for an internal combustion engine, for example, CD an "Exhaust Gas Purification Apparatus for an Internal Combustion Engine" is proposed in the official gazette of Japanese Patent Laid-open No. Hei 3-85316 or an "Exhaust Emission Control Apparatus for a Motorcycle of the Like" is proposed in the official gazette of Japanese Patent Laid-open No. Hei 4-287821.
The apparatus mentioned above is constructed such that, according to FIGS. 1 and 7 of the official

gazette, an exhaust pipe 3 is connected to an exhaust port of an internal combustion engine of a small size which is carried on a motorcycle or the like and an inner pipe 5 of a multiple hole plate extending in the same direction as the exhaust pipe 3 is disposed along an inner wall of the exhaust pipe 3, and a carrying member 8 containing a catalyzer is affixed to a wall face of the inner pipe 5. [0003]
Meanwhile, the apparatus mentioned above is constructed such that, according to FIGS. 3 to 5 of the official gazette, an exhaust muffler 14 is connected to an exhaust port of an internal combustion engine of a small size which is carried on a motorcycle or the like and a catalyzer pipe 23 is disposed at a central portion of a cross section of the exhaust muffler (which corresponds to an exhaust pipe) 14, and a catalyzer 32 is accommodated in the catalyzer pipe 23. The catalyzer 32 includes a catalytic element of a honeycomb structure and a catalytic substance affixed to the catalytic element. [0004] [Subject to Be Solved by the Invention]
Generally, in order for a purification action of a catalyzer to be exhibited sufficiently, it is necessary to

heat the catalyzer to a higher temperature to activate the catalyzer. However, in an internal combustion engine of a small size, it is not easy to raise the temperature of exhaust gas sufficiently to a level at which the catalyzer is activated. Therefore, consideration is required to raise the temperature of the catalyzer as high as possible. in this instance, since the temperature of exhaust gas flowing in the exhaust pipe is high at a central portion of the cross section of the pipe but relatively low in the proximity of the wall of the pipe, this must be taken into consideration.
However, since the apparatus described above has a structure wherein the inner pipe 5 with a catalyzer is disposed along the inner wall of the exhaust pipe 3, it is not easy for the apparatus to exhibit its purification action sufficiently. [0005]
On the other hand, since the apparatus © described above has another structure wherein the catalyzer 32 is disposed at a central portion of the cross section of the exhaust muffler 14 and the temperature of the exhaust gas is comparatively high, it is easy to exhibit its purification action. However, the catalyzer 32

formed from a catalytic element of a honeycomb structure exhibits a pressure loss higher than that of the inner pipe 5 as in the apparatus The objects of the present invention are (1) to allow a purification action to be exhibited sufficiently, (2) to minimize the influence on the performance of an internal combustion engine, and (3) to suppress the cost low.

[0007]
[Means to Solve the Subject]
In order to achieve the objects described above, according to the present invention, there is provided an exhaust emission control apparatus for an internal combustion engine characterized in that a thin steel plate which carries a catalytic metal is disposed at a substantially central portion of a cross section of an exhaust pipe which extends from an exhaust port of the internal combustion engine (corresponding to claim 1). [0008]
The thin steel plate is a tubular member which extends in an axial direction of the exhaust pipe (corresponding to claim 2). [0009]
Preferably, the tubular member is formed from a multiple hole plate and is closed at a portion thereof on the upstream side of exhaust gas (corresponding to claim 3). [0010]
Or, there is provided an exhaust emission control apparatus for an internal combustion engine characterized in that a tubular member of a thin steel plate which

extends in an axial direction of an exhaust pipe extending from an exhaust port of the internal combustion engine and carries a catalytic metal is disposed at a substantially central portion of a cross section of the exhaust pipe, and a partition plate is provided which supports the tubular member of a thin steel plate in the exhaust pipe and blocks up a passage between the tubular member of a thin steel plate and the exhaust pipe (corresponding to claim 4). [0011]
The tubular member of a thin steel plate is attached to the exhaust pipe for expansion in the axial direction (corresponding to claim 5). [0012]
Or, there is provided an exhaust emission control apparatus for an internal combustion engine characterized in that a first carrying member which carries a catalytic metal is disposed in the proximity of and along an inner wall face of an exhaust pipe extending from an exhaust port of the internal combustion engine, and a second carrying member which carries a catalytic metal is disposed at a substantially central portion of a cross section of the first carrying member (corresponding to claim 6).

[0013]
[Operation]
Since the catalytic metal is disposed at a substantially central portion of the cross section of the exhaust pipe at which the temperature of exhaust gas is high, the catalytic metal is activated and exhibits its purification action sufficiently (corresponding to claim
1).
[0014]
Since the thin steel plate is a tubular member which extends in the axial direction of the exhaust pipe, the pressure loss when the exhaust gas passes therethrough is low (corresponding to claim 2).
[0015]
Since the tubular member is closed at a portion thereof on the upstream side of the exhaust gas, the exhaust gas passes through a large number of holes perforated in the wall of the tubular member. Consequently, the exhaust gas contacts with the catalytic metal carried on the front and rear faces of the second carrying member. Accordingly, the contact area between the exhaust gas and the catalytic metal is large, and a high purification action is exhibited (corresponding to claim

3). [0016]
The partition plate partitions the tubular member into forward and rearward portions to control pulsations of exhaust gas from the internal combustion engine to form a generally smooth steady flow. Consequently, since the exhaust emission control apparatus does not exhibit a variation in purification capacity, the purification action is improved. Further, since the tubular member of a thin steel plate is supported by the partition plate for controlling pulsations of exhaust gas, a separate support member is unnecessary (corresponding to claim 4). [0017]
The tubular member of a thin steel plate is expansible in the axial direction with respect to the exhaust pipe, and a difference in elongation amount between the tubular member of a thin steel plate and the exhaust pipe caused by thermal expansion is absorbed (corresponding to claim 5) . [0018]
Since a carrying member which carries a catalytic metal is disposed both in the proximity of the inner wall face of the exhaust pipe and at a substantially central

portion of the cross section of the exhaust pipe, the exhaust gas purification action is further improved without having an influence upon the performance of the internal combustion engine to the utmost {corresponding to claim 6).
Accordingly, the present invention provides an exhaust emission control apparatus for an internal combustion engine, characterized in that a tubular member of a thin steel plate which extends in an axial direction of an exhaust pipe extending from an exhaust port of said internal combustion engine and carries a catalytic metal is disposed at a substantially central portion of a cross section of said exhaust pipe, and a partition plate is provided which supports said tubular member of a thin steel plate in said exhaust pipe and blocks up a passage between said tubular member of thin steel plate and said exhaust pipe.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[FIG. 1]
FIG. 1 is a side elevational view of a motorcycle on which an exhaust emission control apparatus (first embodiment) for an internal combustion engine according to the present invention is mounted. [Fiq. 2]
FIG. 2 is a side elevational view of an exhaust pipe (first embodiment) according to the present invention. [FIG. 3]
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2. [FIG. 4]
FIG. 4 is a sectional view taken along line 4-4 of FIG. 3. [FIG. 5]
FIG. 5 is a perspective view of a second exhaust emission control apparatus (first embodiment) according to the present invention. [FIG. 6]
FIG. 6 is a sectional view taken along line 6-6 of * FJG. 2. -
[FIG. 7]
FIG. 7 is a sectional view taken along line 7-7 of FIG. 6. [FIG. 8]
FIG. 8 is a sectional view taken along line 8-8 of FIG. 6. [FIG. 9]
FIG. 9 is a view illustrating assembly of a second carrying member (first embodiment) according to the present invention. [FIG. 10]
FIG. 10 is a view of a modification of the second carrying member (first embodiment) according to the present invention. [FIG. 11]
FIG. 11 is a view of a modification of a support structure of the second carrying member (first embodiment) according to the present invention. [FIG. 12]
FIG. 12 is a perspective view of a second exhaust emission control apparatus (second embodiment) according to the present invention.
[FIG. 13]
FIG. 13 is a sectional view taken along line 13-13 of FIG. 12. [FIG. 14]
FIG. 14 is a view of a modification of the second exhaust emission control apparatus (second eaibodiment) according to the present invention. [FIG. 15]
FIG. 15 is a sectional view taken along line 15-15 of FIG. 14. [FIG. 16]
FIG. 16 is a schematic view of an exhaust emission control apparatus (third embodiment) according to the present invention.
[Description of Reference Numerals] 1 ... motorcycle,
3 ... internal combustion engine (engine),
4 ... exhaust port, 5 ... exhaust pipe,
5a ... one end portion, 5b ... the other end portion,
6 — muffler,
10 ... first exhaust emission control apparatus,
20 ... exhaust emission control apparatus

(second exhaust emission control apparatus),
21 — first carrying member,
22 ... thin steel plate
(tubular member, second carrying member),
23 ... support member, 27 ... partition plate,
28 ... cap, 29 ... expansion chamber,
50 ... exhaust emission control apparatus
(second exhaust emission control apparatus),
51 — first carrying member,
52 ... second carrying member,
61, 63, 65, 67, 68 exhaust emission control apparatus,
66, 69 ... carrying member.
[Embodiments]
Embodiments of the present invention will be described below with reference to the accompanying drawings. It is to be noted that the drawings should be viewed in the direction of reference numerals.
First, a first embodiment will be described with reference to FIGS. 1 to 9.
FIG. 1 is a side elevational view of a motorcycle on which an exhaust emission control apparatus (first embodiment) for an internal combustion engine according to the present invention is mounted. The motorcycle 1 is constructed such that it includes a 2-cycle engine {internal combustion engine) 3 located in the proximity of the center of a body 2, and an exhaust pipe 5 is connected to an exhaust port 4 of the engine 3 while a muffler 6 is connected to a rear portion of the exhaust apparatus 5. [0020]
FIG. 2 is a side elevational view of the exhaust
pipe (first embodiment) according to the present invention. The exhaust pipe 5 is formed in a circular cross section from a thin steel plate. The exhaust pipe 5 is connected at one end portion 5a thereof to the exhaust port 4 (refer to FIG. 1) of the engine 3 by means of a flange and has the muffler 6 connected to the other end 5b thereof by means of another flange while a first exhaust emission control apparatus 10 on the upstream side of exhaust gas and a second exhaust emission control apparatus 20 on the downstream side of exhaust gas are disposed in the inside of the exhaust pipe 5. The first exhaust emission control apparatus 10 is a front stage purification apparatus while the second exhaust emission control apparatus 20 is a rear stage purification apparatus. [0021]
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 and shows a sectional structure of the first exhaust emission control apparatus 10.
The first exhaust emission control apparatus 10 is formed from an inner pipe 11 disposed in the exhaust pipe 5, The inner pipe 11 is a cylindrical member extending in the same direction as the exhaust pipe 5 along an inner wall of the exhaust pipe 5 and is formed from a multiple


hole plate of a thin steel plate- And, the inner pipe 11 is fixed at one end portion 11a thereof to the exhaust pipe 5 by welding and is supported at the other end portion lib thereof on the exhaust pipe 5 for expansion in an axial direction by a support member 13. Consequently, a difference in elongation amount in the axial direction between the exhaust pipe 5 and the inner pipe 11 caused by thermal expansion can be absorbed.
A noble metal having a catalytic function such as platinum or rhodium is carried on a wall face of the inner pipe 11 having multiple holes (solution containing a noble metal is affixed by application or the like).
It is to be noted that an intermediate portion of the exhaust pipe 5 has such a magnitude that it has an air gap from the inner pipe 11. [0022]
FIG. 4 is a sectional view taken along line 4-4 of FIG. 3. The exhaust pipe 5 has a half-divided cylindrical shape wherein it is divided in a diametrical direction, and the two half parts are unified by welding in a state wherein it contains the inner pipe 11 therein.
The support member 13 is formed from a corrugated plate rolled into a cylindrical configuration with

overlapping faces thereof fixed by spot welding and has corrugations in a circumferential direction. Consequently, the support member 13 is expansible, by an elastic deformation thereof, in a diametrical direction with respect to the exhaust pipe 5 and can absorb a difference in amount of elongation between the exhaust pipe 5 and the inner pipe 11 caused by thermal expansion.
It is to be noted that the support member 13 is not limited to the construction described above which includes a corrugated plate, but may be, for example, wires of stainless steel knitted into a ring-like configuration.
Reference numerals 14, 14 denote a pair of protectors divided in a diametrical direction from each other for covering over the exhaust pipe 5 whose temperature rises high. Those protectors 14, 14 are bolted to nuts 15, — (... represents a plural number; this applies to the following description) welded to an outer periphery of the exhaust pipe 5. [0023J
FIG. 5 is a perspective view of the second exhaust emission control apparatus (first embodiment) according to the present invention. The second exhaust emission control apparatus 20 is constructed such that first carrying


members 21, 21 are disposed in the proximity of and along the inner wall of the exhaust pipe 5, and a second carrying member 22 is disposed at a substantially central portion of the cross section of the first carrying members 21, 21 (at a substantially central portion of the cross section of the exhaust pipe 5). The first carrying members 21, 21 and the second carrying member 22 extend in the axial direction of the exhaust pipe 5.
The first carrying members 21, 21 are formed from a pair of semi-cylindrical members divided in a diametrical direction, and the second carrying member 22 is formed from a straight cylindrical member of a diameter smaller than that of the first carrying members 21, 21. The first carrying members 21, 21 and the second carrying member 22 are each formed from a multiple hole plate of a thin steel plate. And, each of the first carrying members 21, 21 and the second carrying member 22 carries, on its wall having multiple holes, a noble metal having a catalytic function such as platinum or rhodium (solution containing a noble metal is affixed by application of the like).
It is to be noted that the exhaust pipe 5 has such a magnitude that it provides an air gap from the first carrying members 21, 21.

[0024]
FIG. 6 is a sectional view taken along line 6-6 of FIG. 2. on the upstream side of exhaust gas (on the left side in FIG. 6) in the exhaust pipe 5, a support member 23 is provided which supports an end portion 22a of the second carrying member 22 for expansion in the axial direction on the exhaust pipe 5. in particular, the support member 23 includes a cushion member 24 which extends through and supports the one end portion 22a of the second carrying member 22, an annular receiving element 25 which accommodates the cushion member 24 therein, and a bracket 26 for securing the receiving element 25 to the exhaust pipe 5. Consequently, a difference in amount of elongation between the exhaust pipe 5 and the second carrying member 22 in the axial direction caused by thermal expansion can be absorbed. [0025]
On the other hand, on the downstream side of exhaust gas in the exhaust pipe 5 (on the right side in FIG. 6), a partition plate 27 is provided which supports the second carrying member 22 and blocks up a passage between the second carrying member 22 and the exhaust pipe 5. In particular, the partition plate 27 formed from a


mirror plate of a thin steel plate (end plate of a substantially dish shape) is secured, at a flange portion 27a thereof, to the exhaust pipe 5 by plug welding and has the other end portion 22b of the second carrying member 22 inserted in and secured by welding to a through-hole 27b at a substantially central portion of the cross section thereof.
The one end portion (exhaust gas upstream side) 22a of the second carrying member 22 is closed up with a cap 28. [0026]
FIG. 7 is a sectional view taken along line 7-7 of FIG. 6. The cushion member 24 is formed from a corrugated plate rolled into a cylindrical configuration with overlapping faces thereof secured by spot welding, and has corrugations in a circumferential direction. Consequently, the cushion member 24 is expansible, by an elastic deformation thereof, in a diametrical direction with respect to the exhaust pipe 5 and can absorb a difference in amount of elongation between the exhaust pipe 5 and the second carrying member 22 caused by thermal expansion. [0027]
FIG. 8 is a sectional view taken along line 8-8 of

FIG. 6. The opposite end portions of the pair of first carrying members 21, 21 are individually secured by spot welding to portions in the proximity of edge portions of the exhaust pipe 5 divided in a diametrical direction. [0028]
Subsequently, a procedure of assembling the second carrying member 22 of the construction described above will be described with reference to FIGS. 6 and 9.
(a) to (e) of FIG, 9 are illustrative views of assembly of the second carrying member (first embodiment) according to the present invention.
First, the cap 28 is fitted into the one end portion 22a of the second carrying member 22 in (a), and then the one end portion 22a of the second carrying member 22 and the edge portion of the cap 28 are secured to each other to close up the one end portion 22a in (b).
Then, in (c), the other end portion 22b of the second carrying member 22 is inserted into and secured to the through-hole 27b of the partition plate 27 by welding. Thereafter, the receiving element 25 in which the cushion member 24 {not shown) is accommodated is fitted onto the one end portion 22a of the second carrying member 22 to assemble them into the form of (e).

Then, the second carrying member 22 in this form is positioned in the lower half of the exhaust pipe 5 of the half divided state shown in FIG. 6, and the receiving element 25 is welded to the bracket 26 secured in advance. Then, the upper half of the exhaust pipe 5 is placed on the lower half of the exhaust pipe 5, and the upper and lower halves are welded to each other. Then, the exhaust pipe 5 and the flange portion 27a of the partition plate 27 are plug welded to each other, thereby completing an assembling operation. [0029]
Subsequently, operation of the first exhaust emission control apparatus 10 and the second exhaust emission control apparatus 20 will be described with reference to FIGS. 2 and 6.
As shown in FIG. 2, exhaust gas of the engine is introduced into the exhaust pipe 5 from the one end portion 5a side, and when it passes the first exhaust emission control apparatus 10, it contacts and reacts with the noble metal carried in the inner pipe 11 so that it is purified, whereafter it arrives at the second exhaust emission control apparatus 20. [0030]


in the second exhaust emission control apparatus 20, as shown in FIG. 6, the exhaust gas flows from the left side of this figure. However, since the one end portion 22a of the second carrying member 22 is closed up with the cap 28, the exhaust gas does not flow in from the one end portion 22a.
Meanwhile, the exhaust pipe 5 has, at the portion thereof in which the second exhaust emission control apparatus 20 is disposed, a diameter larger than the other portion thereof, and is partitioned into a front portion and a rear portion by the partition plate 27 so as to form the portion of the exhaust pipe 5 on the exhaust gas upstream side into an expansion chamber 29. Consequently, pulsations of the exhaust gas from the engine 3 can be controlled by the expansion chamber 29 to form a generally smooth steady flow. [0031]
Accordingly, the exhaust gas flows in the direction indicated by thin arrow marks in FIG. 6, and the exhaust gas flowing in the proximity of the pipe wall of the exhaust pipe 5 contacts and reacts with and is purified by the noble metal carried on the first carrying members 21, 21.

Further, the exhaust gas passes through the large number of holes perforated in the wall of the second carrying member 22 and enters the second carrying member 22/ whereafter it passes the other end portion 22b and is discharged to the atmospheric air from the exhaust gas downstream side of the exhaust pipe 5. And, when the exhaust gas passes the second carrying member 22, it contacts and reacts with and is purified by the noble metal carried on the second carrying member 22. [0032]
in this instance, since the exhaust gas passes through the large number of holes perforated in the wall of the second carrying member 22 to contact with the catalyzer metal carried on the front and rear faces of the second carrying member 22, the contact area between the exhaust gas and the catalyzer metal is large, and the catalyzer metal sufficiently exhibits a purification action. As described hereinabove, in order for a purification action of a catalyzer to be exhibited sufficiently, the catalyzer must be heated to a high temperature so as to be activated. On the other hand, the temperature of exhaust gas flowing in the exhaust pipe 5 is higher at a central portion of the cross section of the

pipe. Since the second carrying member 22 causes also the exhaust gas of a comparatively high temperature flowing at a central portion of the cross section of the exhaust pipe 5 to contact with the catalytic metal and pass therethrough, the cataly2er is heated to a high temperature and is activated sufficiently so that it sufficiently exhibits a purification action.
Further, since the second carrying member 22 is formed from a tubular member of a multiple hole plate, the pressure loss when exhaust gas passes therethrough is low, and the influence upon the performance of the engine is low.
since exhaust gas contacts and reacts with and is purified by the noble metal carried on the first carrying members 21, 21 and the second carrying member 22, it is purified efficiently. Further, since the exhaust gas is formed into a generally smooth steady flow, the purification capacity of the second exhaust emission control apparatus 20 does not vary, and the exhaust gas "is purified efficiently. [0033]
By the way, the second carrying member 22 is heated to a temperature higher than that of the exhaust

pipe 5 by heat of reaction and so forth. Since the second carrying member 22 is secured at the other end portion 22b thereof to the exhaust pipe 5 by the partition plate 27, if a difference in amount of elongation is produced between the exhaust pipe 5 and the second carrying member 22 by thermal expansion, then the one end portion 22a is elongated in the direction of a blanJc arrow mark to absorb the difference in amount of elongation. Meanwhile, the difference in amount of elongation in a diametrical direction between the exhaust pipe 5 and the second carrying member 22 is absorbed by elastic deformation of the cushion member 24. [0034]
It is to be noted that the second carrying member 22 is closed up on the exhaust gas upstream side, and may have, for example, such structures as shown in FIG. 10.
(a) to (d) of FIG. 10 are views of modifications of the second carrying member (first embodiment) according to the present invention.
(a) shows a construction wherein the one end portion 22a of the second carrying member 22 is closed up with a cap 31 of a multiple hole plate which swells to the exhaust gas upstream side. The cap 31 of a multiple hole

plate is formed by presswork.
(b) shows another construction wherein the one end portion 22a of the second carrying member 22 is pressed flat to form a cap 32.
(c) shows a further construction wherein a plurality of blades of multiple hole plates are attached spirally (in a windmill shape) to the one end portion 22a of the second carrying member 22 to increase the passing resistance of exhaust gas, thereby forming caps 33, ...
(d) shows a still further construction wherein the
one end portion 22a of the second carrying member 22 is
closed up with a cap 34 of a multiple hole plate in the
form of a flat plate. It is to be noted that, in place of
attachment of the cap 34 of a multiple hole plate in the
form of a flat plate, the one end portion 22a itself may be
folded back to the center side of the second carrying
member 22 to form a cap in the form of a flat plate to
close up the exhaust gas upstream side.
Since the caps 31 to 34 of (a) to (d) have operations similar to that of the construction of the first embodiment and besides are each formed from a multiple hole plate, the pressure loss which arises from the provision of the caps 31 to 34 is lower than that of the construction of

the first embodiment. [0035]
The supporting structure for the second carrying member 22 is such that an end of the second carrying member 22 is supported on the exhaust pipe 5 for expansion in the axial direction and the other end is secured to the exhaust pipe 5, and may alternatively have, for example, such constructions as shown in PIG, 11.
(a) to (h) of FIG. 11 are views of modifications of the supporting structure for the second carrying member (first embodiment) according to the present invention. It is to be noted that exhaust gas flows in the direction of thin arrow marks in FIG. 11, and the one end portion 22a of the second carrying member 22 is elongated in the direction of a blank arrow mark by thermal expansion. [0036]
(a) shows a construction wherein the one end portion 22a of the second carrying member 22 extends to the exhaust gas upstream side farther than the support member 23 and is closed up with the cap 28 in the form of a flat plate.
(b) shows another construction wherein the exhaust gas upstream side of the support member 23 (left side in

this figure) is closed up with a cap 36, and a gap S3, which is larger than the amount of elongation of the second carrying member 22 by thermal expansion is provided between the one end portion 22a and the cap 36. In this instance, there is no need of mounting a cap at the one end portion 22a of the second carrying member 22.
(c) shows a further construction wherein the
receiving element 25 of the support member 23 is longer
than the bracket 26 in the axial direction of the exhaust
pipe 5.
[0037]
(d) shows one-end supported construction wherein
the second carrying member 22 is supported only on the
partition plate 27. A support member 37 includes a cushion
member 38 which supports the other end portion 22b of the
second carrying member 22 on the exhaust pipe 5 for
expansion in the axial direction, a receiving element 39
for accommodating the cushion member 38, and a partition
plate 27 for securing the receiving element 39 to the
exhaust pipe 5. A gap S2 is provided between the other end
portion 22b and a flange 39a of the receiving element 39,
and the amount of movement and the amount of elongation of
the other end portion 22b are restricted within the range

of the gap s2.
(e) shows a modification to the construction of
(d), and the lengths of the cushion member 38 and the
receiving element 39 are shorter than those in the
construction of (d).
[0038]
(f) shows an opposite-end supported construction
wherein the one end portion 22a of the second carrying
member 22 is secured to the exhaust pips 5 by means a
bracket 41 while the other end portion 22b of the second
carrying member 22 is supported for expansion in the axial
direction of the exhaust pipe 5 by means of a support
member 42. The support member 42 includes a cushion member
43 which supports the other end portion 22b of the second
carrying member 22 for expansion in the axial direction of
the exhaust pipe 5, a receiving element 44 for
accommodating the cushion member 43f and a partition plate
27 for securing the receiving element 44 to the exhaust
pipe 5. The other end portion 22b extends to the exhaust
gas downstream side (left side of this figure) farther than
the support member 42.
(g) shows a modification to the construction of (f) and is a construction wherein a cap 45 with a cut and

raised pawl is attached to the one end portion 22a of the second carrying member 22 to close up the one end portion 22a.
(h) shows a modification to the cushion members 24, 38 and 43 and is a construction of a cushion member 48 formed by knitting stainless steel wires into a ring. For example, a support member 46 includes a seat plate 47 rolled around the other end portion 22b of the second carrying member 22, two front and rear cushion members 48, 48 in which the seat plate 47 is inserted to support the other end portion 22b for expansion in the axial direction of the exhaust pipe 5, a cylindrical receiving element 49 which accommodates the cushion members 48, 48, and a partition plate 27 for securing the receiving element 49 to the exhaust pipe 5. [0039]
Subsequently, a second embodiment will be described with reference to FIGS. 12 and 13.
FIG. 12 is a perspective view of a second exhaust emission control apparatus (second embodiment) according to the present invention. The second exhaust emission control apparatus 5 0 is constructed such that a first carrying member 51 is disposed in the proximity of and along an


inner wall face of an exhaust pipe 5 while a second carrying member 52 is disposed at a substantially central portion of the cross section of the first carrying member 51 (at a substantially central portion of the cross section of the exhaust pipe 5). The first carrying member 51 and the second carrying member 52 extend in an axial direction of the exhaust pipe 5.
The first carrying member 51 is formed from a cylindrical member and has a pair of cone portions 51a, 51a at the opposite end portions thereof in the axial direction. One or both of the cone portions 51a, 51a are secured by welding to the exhaust pipe 5. The second carrying member 52 is formed from a flat plate, and one end or both ends thereof in a longitudinal direction are secured by welding in the first carrying member 51.
The first carrying member 51 and the second carrying member 52 are each formed from a multiple hole plate of a thin steel plate. And, a noble metal having a catalytic function such as platinum or rhodium is carried on the multiple hole wall faces of the first carrying member 51 and the second carrying member 52 (solution containing the noble metal is affixed by application or the like).

[0040]
FIG. 13 is a sectional view taken along line 13-13 of FIG- 12 and shows a state wherein the second carrying member 52 formed from a flat plate is erected uprightly in the first carrying member 51. [0041]
Subsequently, operation of the second exhaust emission control apparatus 50 of the construction of the second embodiment described above will be described with reference to FIG. 12.
Exhaust gas of an engine flows in the direction indicated by thin arrow marks in this figure, and exhaust gas flowing in the proximity of the pipe wall flows passing through a large number of holes perforated in the wall of the first carrying member 51 while exhaust gas flowing at a substantially central portion of the cross section flows passing through a large number of holes perforated in the wall of the second carrying member 52. Consequently, the exhaust gas contacts and reacts with and is purified by the noble metal carried on the first carrying member 51 and the second carrying member 52. [0042]
in this instance, since the exhaust gas passes

through the large number of holes perforated in the wall of the second carrying member 52 and contacts with the catalytic metal carried on the front and rear faces of the second carrying member 52, the contact area between the exhaust gas and the catalytic metal is large, and the catalytic metal sufficiently exhibits a purification action.
Further, since the noble metal carried on the second carrying member 52 contacts with the exhaust gas of a comparatively high temperature which flows at a central portion of the cross section of the exhaust pipe 5, it is heated to a high temperature and activated sufficiently so that it sufficiently exhibits its purification function.
Further, since the second carrying member 52 is formed from a flat plate extending in the axial direction of the exhaust pipe 5, the pressure loss when the exhaust gas passes therethrough is reduced further from that of the construction of the first embodiment described above. [0043]
It is to be noted that the second exhaust emission control apparatus of the construction of the second embodiment described above may alternatively have such constructions as, for example, shown in FIGS. 14 and 15.

FIG. 14 is a view of a modification of the second exhaust emission control apparatus (second embodiment) according to the present invention. The first carrying member 51 has a sectional shape of a broken circle wherein a cylindrical member is partially cut away in a diametrical direction (for example, at a lower portion in this figure). [0044]
FIG. 15 is a sectional view taken along line 15-15 of FIG. 14. The first carrying member 51 has a pair of flange portions 51b, 51b folded back from the opposite edges of the cross section of the broken circle/ and the flange portions 51b, 51b contact with the inner wall of the exhaust pipe 5. The second carrying member 52 extends through the broken circle portion of the first carrying member 51 and contacts with the inner wall of the exhaust pipe 5. [0045]
Subsequently, a third embodiment will be described with reference to FIG. 16.
(a) to (e) are schematic views of exhaust emission control apparatus (third embodiment) according to the present invention.
The exhaust emission control apparatus 61 of (a)

is constructed such that two front and rear stages of purification apparatus are disposed in an exhaust pipe 5, and besides, a control valve (for example, a butterfly valve) for controlling the amount of exhaust gas is interposed between the front stage purification apparatus and the rear stage purification apparatus. The front stage purification apparatus has the construction of the first exhaust emission control apparatus 10 described hereinabove with reference to FIG. 3 while the rear stage purification apparatus has the construction of the second exhaust emission control apparatus 50 described hereinabove with reference to FIG. 12-[0046]
The exhaust emission control apparatus 63 of (b) is constructed such that three front to rear stage purification apparatus are disposed in an exhaust pipe 5. The front stage purification apparatus has the construction of the first exhaust emission control apparatus 10 described hereinabove with reference to FIG. 3 and the middle stage purification apparatus has the construction of the second exhaust emission control apparatus 50 described hereinabove with reference to FIG. 12 while the rear stage purification apparatus is construction of a derivation pipe
64 which extends from the other end portion 5b of the exhaust pipe 5 into the exhaust pipe 5. The derivation pipe 64 is formed from a multiple hole plate of a thin steel plate, and a noble metal having a catalytic function such as platinum or rhodium is carried on a wall face of the derivation pipe 64 having multiple holes (solution containing the noble metal is affixed by application or the like). [0047]
The exhaust emission control apparatus 65 of (c) is constructed such that a carrying member 66 extending in an axial direction of an exhaust pipe 5 is disposed at a substantially central portion of the cross section of the exhaust pipe 5, The carrying member 66 is a flat plate formed from a multiple hole plate of a thin steel plate, and a noble metal having a catalytic function such as platinum or rhodium is carried on a wall face of the carrying member 66 having multiple holes (solution containing the noble metal is affixed by application or the like).
The exhaust emission control apparatus 67 of (d) is a modification to the construction of (c) described above. The carrying member 66 is formed from a corrugated
plate in place of a flat plate. [0048]
The exhaust emission control apparatus 68 of (e) is constructed such that a semi-cylindrical carrying member 69 which extends in an axial direction of an exhaust pipe 5 and is closed up at the opposite ends thereof in the axial direction is disposed. The carrying member 69 has a diametrical direction open end 69a disposed at a substantially central portion of the cross section of the exhaust pipe 5. And, the carrying member 69 is formed from a multiple hole plate of a thin steel plate, and a noble metal having a catalytic function such as platinum or rhodium is carried on a wall face of the carrying member 69 having multiple holes (solution containing the noble metal is affixed by application or the like).
The carrying members 66 and 69 of the constructions of (c) to (e) constructed in such a manner as described above may be used for one stage or a plurality of stages of such multiple stage purification apparatus disposed in the exhaust pipe 5 as those in (a) and (b). [0049]
It is to be noted that, in the first, second and third embodiments and the modifications to them described

above, the "thin steel plate" which carries the catalytic metal is disposed at a substantially central portion of the cross section of the exhaust pipe 5 or at a substantially central portion of the cross section of the first carrying members 21 or member 51, and as concrete illustrations, in the first embodiment shown in FIGS. 1 to 9 and the modifications shown in FIGS. 10 and 11, it constructs the second carrying member 22 formed from a tubular member of a multiple hole plate; in the second embodiments shown in FIGS. 12 and 13, the modifications shown in FIGS. 14 and 15 and the third embodiment shown in (a) of FIG. 16 and (b) of FIG. 16, it constructs the second carrying member 52 formed from a flat plate of a multiple hole plate; and in the third embodiment shown in (c) to (e) of FIG. 16, it constructs the carrying members 66 and 69 each formed from a flat plate of a multiple hole plate, a corrugated plate or a semi-cylinder.
In this manner, the "thin steel plate" is not limited to the constructions of the embodiments or the modifications to them or not limited to a plate of a multiple hole plate. Further, also the shape of the holes of the multiple hole plate and the size and the quantity of the holes are optional.

[0050]
[Effects of the Invention]
The present invention exhibits the following effects due to the construction described above.
With the exhaust emission control apparatus for an internal combustion engine as recited in claim 1, since a thin steel plate which carries a catalytic metal is disposed at a substantially central portion of the cross section of an exhaust pipe which extends from an exhaust port of an internal combustion engine, the catalytic metal is disposed at a substantially central portion of the cross section of the exhaust pipe at which the temperature of the exhaust gas is high, the catalytic metal can be activated to exhibit its purification action sufficiently, and besides the exhaust emission control apparatus can be produced at a low cost. [0051]
With the exhaust emission control apparatus for an internal combustion engine as recited in claim 2, since the thin steel plate is a tubular member which extends in an axial direction of the exhaust pipe, the pressure loss when the exhaust gas passes therethrough is reduced, and consequently, no influence is had on the performance of the

internal combustion engine. [0052]
with the exhaust emission control apparatus for an internal combustion engine as recited in claim 3, since the tubular member is formed from a multiple hole plate and is closed at a portion thereof on the upstream side of exhaust gas, the exhaust gas passes through the large number of holes perforated in the wall of the tubular member, and consequently, the exhaust gas contacts with the catalytic metal carried on the front and rear faces of the second carrying member. Accordingly, the contact area between the exhaust gas and the catalytic metal is increased and a purification action is promoted. [0053]
With the exhaust emission control apparatus for an internal combustion engine as recited in claim 4, since a tubular member of a thin steel plate which extends in an axial direction of an exhaust pipe extending from an exhaust port of the internal combustion engine and carries a catalytic metal is disposed at a substantially central portion of the cross section of the exhaust pipe and a partition plate is provided which supports the tubular member of a thin steel plate in the exhaust pipe and blocks

up a passage between the tubular member of a thin steel plate and the exhaust pipe, the catalytic metal is disposed at a substantially central portion of the cross section at which the temperature of the exhaust gas is high, and consequently, the catalytic metal can be activated to sufficiently exhibit a purification function and besides the exhaust emission control apparatus can be produced at a low cost. Further, since the partition plate partitions the tubular member of a thin steel plate into forward and rearward portions to control pulsations of the exhaust gas from the internal combustion engine to form a generally smooth steady current, the purification capacity of the exhaust emission control apparatus does not vary and the purification action can be exhibited sufficiently. Further, since the tubular member of a thin steel plate is supported by the partition plate for controlling pulsations of exhaust gas, a separate support member is unnecessary and the supporting structure is simple. [0054]
With the exhaust emission control apparatus for an internal combustion engine as recited in claim 5, since the tubular member of a thin steel plate is attached to the exhaust pipe for expansion in the axial direction, a

diflerence in elongation amount between the tubular member and the exhaust pipe caused by thermal expansion can be absorbed readily. [0055]
With the exhaust emission control apparatus for an internal combustion engine as recited in claim 5, since a first carrying member which carries a catalytic metal is disposed in the proximity of and along an inner wall face of an exhaust pipe extending from an exhaust port of the internal combustion engine and a second carrying member which carries a catalytic metal is disposed at a substantially central portion of the cross section of the first carrying member, the carrying members on which the catalytic metal is carried are disposed both in the proximity of the inner wall face and at the substantially central portion of the cross section of the exhaust pipe, the exhaust gas purification action can be further improved without having an influence upon the performance of the internal combustion engine to the utmost, and besides the exhaust emission control apparatus can be produced at a low cost.






WE CLAIM:
1. An exhaust emission control apparatus for an internal combustion engine, characterized in that a tubular member of a thin steel plate which extends in an axial direction of an exhaust pipe extending from an exhaust port of said internal combustion engine and carries a catalytic metal is disposed at a substantially central portion of a cross section of said exhaust pipe, and a partition plate is provided which supports said tubular member of a thin steel plate in said exhaust pipe and blocks up a passage between said tubular member of thin steel plate and said exhaust pipe.
2. An exhaust emission control apparatus for an internal combustion engine as claimed in claim 1, wherein said tubular member is formed from a multiple hole plate and is closed at a portion thereof on the upstream side of exhaust gas.
3. An exhaust emission control apparatus for an internal combustion engine as claimed in claim 1, wherein said tubular member of thin steel plate is attached to said exhaust pipe for expansion in the axial direction.
4. An exhaust emission control apparatus for an internal combustion engine as claimed in claim 1, wherein said tubular carrying said member which carries said catalytic metal is disposed in the proximity of and along an inner wall face of an exhaust pipe extending from an exhaust port of said internal combustion engine.

5. An exhaust emission control apparatus substantially as
hereinbefore described with reference to and as illustrated in the
accompanying drawings.

Documents:

1277-del-1996-abstract.pdf

1277-del-1996-claims.pdf

1277-del-1996-complete specification (granted).pdf

1277-del-1996-correspondence-others.pdf

1277-del-1996-correspondence-po.pdf

1277-del-1996-description (complete).pdf

1277-del-1996-drawings.pdf

1277-del-1996-form-1.pdf

1277-del-1996-form-13.pdf

1277-del-1996-form-2.pdf

1277-del-1996-form-3.pdf

1277-del-1996-form-4.pdf

1277-del-1996-gpa.pdf

1277-del-1996-pct-210.pdf

1277-del-1996-petition-137.pdf

1277-del-1996-petition-138.pdf

abstract.jpg


Patent Number 247619
Indian Patent Application Number 1277/DEL/1996
PG Journal Number 17/2011
Publication Date 29-Apr-2011
Grant Date 27-Apr-2011
Date of Filing 10-Jun-1996
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 YOSHIYASU UCHIDA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
2 NOBUHIKO ITOU C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
3 HIROSHI IOKAWA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
4 KENJIRO SAITO C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
5 NOBUHIRO SHIMADA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
PCT International Classification Number F02D 1/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA