Title of Invention

''EXHAUST EMISSION CONTROL DEVICE FOR ENGINE'

Abstract An exhaust emission control device for an engine, comprising a catalytic converter (10) intermediately disposed in an exhaust passage (5, 6) of said engine (E), wherein an exhaust gas introducing chamber (21) to which an upstream portion of said exhaust passage (5, 6) is connected and an exhaust gas discharging chamber (22) to which a downstream portion of said exhaust passage (5, 6) is connected are formed at one end portion of said catalytic converter (10) to communicate, in parallel, with a catalyst chamber (25, 26) of said catalytic converter (10); an exhaust gas reversing chamber (23, 34) by which an exhaust gas having passed from said exhaust gas introducing chamber (21) through said catalyst chamber (25, 26) is guided again through said catalyst chamber (25, 26) into said exhaust gas discharging chamber (22) is formed at the other end portion of said catalytic converter (10) ; and the relationship of the following expression (1) as herein described, is established, where A is the total volume of said catalyst chamber (25, 26) and B is the volume of said exhaust gas reversing chamber (23, 34). Fig. 4
Full Text [Name of Document] Specification [Title of the Invention]
Exhaust Emission Control Device for Engine [Technical Field] [0001]
TThe present invention relates to an improvement in an exhaust emission control device for an engine, including a catalytic converter intermediately disposed in an exhaust passage of the engine./ [Background Art] [0002]
Such an exhaust emission control device for an engine has already been known, as disclosed in Patent Documents 1 and 2.
[Patent Document 1]
Japanese Utility Model Publication No. Sho 60-29625 [Patent Document 2]
Japanese Patent Laid-open No. Hei 8-68316 [Disclosure of the Invention] [Problems to be Solved by the Invention] [0003]
In such a conventional exhaust emission control device for an engine, the exhaust gas to be clarified (to be subjected to emission control) is caused to flow

through the catalytic converter in one direction. In this case, therefore, if the passage length in the catalytic converter is enlarged in order to enhance the exhaust gas clarification efficiency (exhaust emission control efficiency), the overall length of the catalytic converter would be enlarged and the exhaust system for the engine would be enlarged in length and size.
[0004]
The present invention has been made in consideration of the above-mentioned circumstances. Accordingly, it is an object of the present invention to provide an exhaust emission control device for an engine in which the effective passage length of a catalytic converter can be increased without increasing the overall length of the catalytic converter, to thereby contribute to enhancement of exhaust gas clarification efficiency.
[Means for Solving the Problems]
[0005]
In order to attain the above object, the present invention is firstly characterized in that, in an exhaust emission control device for an engine, including a catalytic converter intermediately disposed in an exhaust passage of the engine, an exhaust gas introducing chamber to which an upstream portion of the exhaust passage is

connected and an exhaust gas discharging chamber to which a downstream portion of the exhaust passage is connected are formed at one end portion of the catalytic converter so as to communicate, in parallel, with a catalyst chamber of the catalytic converter; an exhaust gas reversing chamber by which an exhaust gas having passed from the exhaust gas introducing chamber through the catalyst chamber is guided again through the catalyst chamber into the exhaust gas discharging chamber is formed at the other end portion of the catalytic converter; and the relationship of the following expression (1):
is established, where A is the total volume of the catalyst chamber, and B is the volume of the exhaust gas reversing chamber. [0006]
Incidentally, the just-mentioned exhaust passage corresponds to the exhaust pipe 5 and the exhaust muffler 6 in the embodiments of the present invention which will be described later. [0007]
Besides, the present invention is secondly characterized in that, in addition to the first

characteristic, the catalyst chamber is partitioned into a first catalyst chamber communicating with the exhaust gas introducing chamber and a second catalyst chamber communicating with the exhaust gas discharging chamber, and the first and second catalyst chambers are made to communicate with each other through the exhaust gas reversing chamber. [0008]
Further, the present invention is thirdly characterized in that, in addition to the second characteristic, the first catalyst chamber and the second catalyst chamber are so formed that one of them surrounds the other of them. [0009]
Furthermore, the present invention is fourthly characterized in that, in addition to the second or third characteristic, a partition member for partitioning the first and second catalyst chambers from each other is disposed between the first catalyst chamber and the second catalyst chamber. [0010]
Incidentally, the just-mentioned partition member corresponds to the partition tube 28 in the embodiments of the present invention which will be described later.

[0011]
Further, the present invention is fifthly
characterized in that, in addition to any of the first to fourth characteristics, the catalytic converter is disposed directly under the engine.
[0012]
Furthermore, the present invention is sixthly characterized in that, in addition to any of the first to fourth characteristics, the catalytic converter is disposed in an exhaust muffler included in the exhaust passage.
[Effects of the Invention]
[0013]
According to the first characteristic of the present invention, in the catalytic converter the exhaust gas having passed from the exhaust gas introducing chamber into the catalyst chamber is reversed (turned back) in the exhaust gas reversing chamber, is made to pass the catalyst chamber again and is guided into the exhaust gas discharging chamber, so that the exhaust gas flows forwards and reverse through the catalyst chamber. Therefore, the total passage length in the catalyst chamber is practically made equal to two times of the overall length of the catalytic converter. Accordingly,

the effective passage length of the catalytic converter can be largely increased, without increasing the overall length of the catalytic converter, whereby the exhaust emission control device can be made compact. [0014]
Moreover, the forward flow and the reverse flow of the exhaust gas in the catalyst chamber are brought into mutual heating, whereby it is possible to achieve early activation of the first and second catalyst chambers after the starting of the engine, there contributing to an effective enhancement of the exhaust gas clarification efficiency. [0015]
Further, the ratio A/B of the volume A of the catalyst chamber to the volume B of the exhaust gas reversing chamber is set in the range of from 0.1 to 4.0, exclusive, whereby it is possible at least to obviate a lowering in the engine output performance. [0016]
According to the second characteristic of the present invention, in the catalytic converter, the forward flow of the exhaust gas passing through the first catalyst chamber and the reverse flow of the exhaust gas passing through the second catalyst chamber are prevented

from interfering with each other, whereby an increase in the back pressure of the engine can be suppressed, thereby contributing to enhancement of the engine output performance. [0017]
According to the third characteristic of the present invention, the area of contact between the first and second catalyst chamber can be easily broadened, and activation of the first and second catalyst chamber can be more promoted. [0018]
According to the fourth characteristic of the present invention, in the catalytic converter, the forward flow of the exhaust gas passing through the first catalyst chamber and the reverse flow of the exhaust gas passing through the second catalyst chamber can be securely prevented from interfering with each other, whereby an increase in the back pressure of the engine can be suppressed, thereby contributing to enhancement of the engine output performance. [0019]
According to the fifth characteristic of the present invention, it is possible to install a compact catalytic converter through utilization of a dead space

directly under the engine.
[0020]
According to the sixth characteristic of the present invention, it is possible to install a compact catalytic converter through utilization of a dead space in the exhaust muffler. At the same time, the catalytic converter can be heat-insulated (heat-retained) by the exhaust muffler, thereby effectively promoting the early activation of the catalytic converter, and the silencing effect can be enhanced by the catalytic converter.
[Best Mode for Carrying out the Invention]
[0021]
Now, some modes of carrying out the present invention will be described below, referring to preferred embodiments thereof shown in the accompanying drawings.
[Brief Description of the Drawings]
[0063]
[FIG. 1]
FIG. 1 is a side view of a motorcycle provided with an exhaust emission control device for an engine according to a first embodiment of the present invention. [FIG. 2]
FIG. 2 is an enlarged side view of the vicinity of the engine shown in FIG. 1. [FIG. 3]
FIG. 3 is a view taken along arrow 3 in FIG. 2. [FIG. 4]
FIG. 4 is an enlarged longitudinal sectional view of the exhaust emission control device, taken along line
4-4 of FIG. 3. [FIG. 5]
FIG. 5 is a sectional view taken along line 5-5 of FIG. 4. [FIG. 6]
FIG. 6 is a view corresponding to FIG. 4, showing a second embodiment of the present invention. [FIG. 7]
FIG. 7 is a sectional view taken along line 7-7 of FIG. 6. [FIG. 8]
FIG. 8 is a view corresponding to FIG. 6, showing a third embodiment of the present invention. [FIG. 9]
FIG. 9 is a view corresponding to FIG. 6, showing a fourth embodiment of the present invention. [FIG. 10]
FIG. 10 is a sectional view taken along line 10-10 of FIG. 9. [FIG. 11]
FIG. 11 is a longitudinal sectional view of an exhaust muffler, showing a fifth embodiment of the
present invention.
FIG. 12 is a diagram of comparison in performance
between the device according to the present invention and a conventional device in performance.

[0022]
FIG. 1 is a side view of a motorcycle provided with an exhaust emission control device for an engine according to a first embodiment of the present invention; FIG. 2 is an enlarged side view of the vicinity of the engine in FIG. 1; FIG. 3 is a view taken along arrow 3 in FIG. 2; FIG. 4 is an enlarged longitudinal sectional view of the exhaust emission control device, taken along line 4-4 of FIG. 3; FIG. 5 is a sectional view taken along
line 5-5 of FIG. 4; FIG. 6 is a view, corresponding to FIG. 4, showing a second embodiment of the invention; FIG.
7 is a sectional view taken along line 7-7 of FIG. 6; FIG.
8 is a view, corresponding to FIG. 6, showing a third
embodiment of the invention; FIG. 9 is a view,
corresponding to FIG. 6, showing a fourth embodiment of
the invention; FIG. 10 is a sectional view taken along
line 10-10 of FIG. 9; FIG. 11 is a longitudinal sectional
view of an exhaust muffler, showing a fifth embodiment of
the invention; and FIG. 12 is a diagram of comparison in
performance between the device according to the invention
and a conventional device.
[0023]
First, the first embodiment of the present invention shown in FIGS. 1 to 5 will be described as follows.
[0024]
In FIG. 1, the motorcycle M has a configuration in which an engine E for driving a rear wheel 2r is mounted on a central portion of a vehicle body 1 supporting a front wheel 2f and the rear wheel 2r. The engine E is a 4-cycle type engine in which a cylinder part 4 is projected slightly upwards from a front surface of a crankcase 3. An exhaust pipe 5 communicating an exhaust
port inside the cylinder part 4 is attached to a lower surface of the cylinder part 4, and an exhaust muffler 6 disposed on one lateral side of the rear wheel 2r is connected to the rear end of the exhaust pipe 5.
[0025]
As shown in FIGS. 2 and 3, an exhaust emission control device D includes a cylindrical catalytic converter 10 provided at an intermediate portion of the exhaust pipe 5. The exhaust emission control device D is disposed directly under and within the lateral width of the crankcase 3, with both ends in the slot direction thereof set in the left-right direction of the motorcycle M, and on the front side of a step bar 11 bolt-connected to a bottom surface of the crankcase 3. Thus, a dead space directly under the engine E is utilized for disposing the exhaust emission control device D, and thermal influence of the exhaust emission control device D on left and right steps 12, 12 attached to both ends of the step bar 11 can be obviated.
[0026]
The exhaust pipe 5 is divided, at the exhaust emission control device D, into an upstream exhaust pipe 5a continuous with the engine E and a downstream exhaust pipe 5b continuous with the exhaust muffler 6, and each
of the upstream and downstream exhaust pipes 5a and 5b is connected to one end portion in the longitudinal direction of the exhaust emission control device D.
[0027]
Over the range from a downstream portion of the upstream exhaust pipe 5a to the downstream exhaust pipe 5a, 5b, a protector plate 13 for covering the outside surfaces of them is mounted, and the exhaust emission control device D is fitted with an under guard plate 14 for covering a lower surface thereof.
[0028]
In FIGS. 4 and 5, the exhaust emission control device D includes a cylindrical three way catalytic converter 10, and a first cap 18 and a second cap 19 which are dome-like in shape and connected respectively to both end portions in the slot direction of the catalytic converter 10.
[0029]
The catalytic converter 10 includes a hollow-cylindrical shell 16 opened at both ends thereof, and a honeycomb-shaped catalyst support 17 which has a multiplicity of passages 24, 24, extending in the axial direction thereof and is firmly fitted to the inner peripheral surface of the shell 16. The catalyst support
17 supports a catalyst such as rhodium, palladium, etc. fronting on the multiplicity of passages 24, 24, The honeycomb-shaped catalyst support 17 has a configuration in which, for example, a flat sheet 17a and a corrugated sheet 17b made of stainless steel and laid on each other are wound spirally and closely, as clearly shown in FIG. 5. [0030]
The first and second caps 18 and 19 are fittedly connected respectively to both end portions of the shell 16. The first cap 18 is provided with a partition wall 20 for partitioning the inside thereof into an exhaust gas introducing chamber 21 and an exhaust gas discharging chamber 22, and the upstream exhaust pipe 5a and the downstream exhaust pipe 5b connected to the first cap 18 communicate with the exhaust gas introducing chamber 21 and the exhaust gas discharging chamber 22, respectively. [0031]
The partition wall 20 is disposed close to and perpendicularly to one end face of the catalyst support 17 so as to equally bisect the end face, whereby the multiplicity of passages 24, 24 of the catalyst support 17 are divided into a group in a first catalyst chamber 25 communicating with the exhaust gas introducing

chamber 21 and a group in a second catalyst chamber 26 communicating with the exhaust gas discharging chamber 22 [0032]
The inside of the second cap 19 is made to be an exhaust gas reversing chamber 23 through which the first and second catalyst chambers 25 and 26 communicate with each other. [0033]
In the foregoing, the total volume A of the first and second catalyst chambers 25 and 26 and the volume B of the exhaust gas reversing chamber 23 are so set as to satisfy the following expression (1) . [0034]
0.1 Desirably, the ratio A/B is set a value of approximately 1.5. [0035]
Now, the operation of the first embodiment will be described below. [0036]
During an operation of the engine E, the exhaust gas discharged from the exhaust port of the engine E flows first through the upstream exhaust pipe 5a into the exhaust gas introducing chamber 21, then passes through
the multiplicity of passages 24, 24 • • • constituting the first catalyst chamber 25 into the exhaust gas reversing chamber 23, is reversed (turned back) to the second catalyst chamber 26 side, passes through the multiplicity
of passages 24, 24 • • • of the second catalyst chamber 26,
and flows out into the downstream exhaust pipe 5b.
[0037]
Meanwhile, when the catalytic converter 10 having the first and second catalyst chambers 25 and 26 is activated by the heat of the exhaust gas passing therethrough and by the radiant heat from the engine E, NOx in the exhaust gas is reduced to nitrogen gas and CO and HC are oxidized, in the first and second catalyst chambers 25 and 26, whereby the three noxious components are turned innoxious. In the catalytic converter 10 in the present invention, the first and second catalyst chambers 25 and 26 are arranged to be parallel and adjacent to each other, and the exhaust gas having passed through the first catalyst chamber 25 is reversed (turned back) in the exhaust gas reversing chamber 23, before passing through the second catalyst chamber 26. Therefore, the total passage length in the first and second catalyst chambers 25 and 26 is equal to two times the overall length of the catalyst support 17. Accordingly, the
effective passage length of the catalyst support 17 can be largely increased, without increasing the overall length of the catalyst support 17, and the exhaust emission control device can be made compact. As a result, the exhaust emission control device can be installed in a narrow dead space directly under the engine E.
[0038]
Moreover, the first and second catalyst chambers 25 and 26 heat each other through the adjacent portions thereof, and, simultaneously, the area of the outer peripheral surface of the catalyst support 17 is set small to thereby suppress heat radiation as securely as possible. This ensures that early activation of the first and second catalyst chambers 25 and 26 can be achieved, thereby contributing to enhancement of the exhaust gas clarification efficiency (exhaust emission control efficiency).
[0039]
FIG. 12 shows the relationship between the ratio A/B of the total volume A of the first and second catalyst chambers 25, 26 to the volume B of the exhaust gas reversing chamber 23 and the output enhancing ratio a of the engine E, based on test results. Here, the output enhancing ratio a. is obtained according to the expression
shown below. In the expression, P is the maximum output of the engine E using the device according to the present invention, and Q is the maximum output of an engine provided with a conventional device in which first and second catalyst chambers 25 and 26 are connected in a rectilinear form. [0040]
a(%) = (P - Q) x 100/P
The tests were conducted for three kinds of engines with different displacements of 50 cc, 150 cc, and 200 cc, with the value of A/B varied. [0041]
As a result, it was confirmed that when A/B is set in the range of from 0.1 to 4.0, the engine output enhancing ratio can be made not less than 0%, i.e., it is possible at least to prevent engine output performance from being lowered, and when A/B is set to about 1.5, the output enhancing ratio can be substantially maximized. [0042]
In the next place, a second embodiment of the present invention shown in FIG. 6 will be described below. [0043]
In the second embodiment, in a first cap 18, a hollow-cylindrical partition wall 20 having a funnel-like
open end facing one end face of a catalyst support 17 is disposed concentrically with the catalyst support 17. The partition wall 20 is firmly attached to the first cap 18, a cylindrical exhaust gas introducing chamber 21 is defined by the inner peripheral surface of the partition wall 20, and an annular exhaust gas discharging chamber 22 surrounding the exhaust gas introducing chamber 21 is defined by the outer peripheral surface of the partition wall 20 and the inner peripheral surface of the first cap 18. Of course, an upstream exhaust pipe 5a is connected to the exhaust gas introducing chamber 21, and a downstream exhaust pipe 5b to the exhaust gas discharging chamber 22. The other configurations are the same as in the preceding embodiment; therefore, the portions corresponding to those in the preceding embodiment will be denoted by the same reference symbols as used above, and descriptions of them will be omitted. Accordingly, in the second embodiment also, the ratio A/B of the total volume A of first and second catalyst chambers 25 and 26 to the volume B of an exhaust gas reversing chamber 23 is set in the same manner as in the case of the first embodiment. [0044]
According to the second embodiment, the hollow-
cylindrical partition wall 20 for partitioning the interior of the first cap 18 into the cylindrical exhaust gas introducing chamber 21 and the hollow-cylindrical exhaust gas discharging chamber 22 surrounding the exhaust gas introducing chamber 21 is opposed to the one end face of the catalyst support 17. As a result, a multiplicity of passages 24, 24 • • • in the catalyst support 17 are divided into a group in a cylindrical first catalyst chamber 25 communicating with the exhaust gas introducing chamber 21, and a group in a hollow-cylindrical second catalyst chamber 26 communicating with the exhaust gas discharging chamber 22 and surrounding the first catalyst chamber 25. [0045]
Therefore, an exhaust gas having passed from the exhaust gas introducing chamber 21 through the multiplicity of passages 24, 24, • • • into the exhaust gas reversing chamber 23 is reversed (turned back) while spreading radially, and then proceeds inside the second catalyst chamber 26 toward the exhaust gas discharging chamber 22. Accordingly, the first catalyst chamber 25 can be effectively heat-insulated (heat-retained), and heated, by the second catalyst chamber 26, whereby activation of the catalyst support 17 can be more
accelerated.
[0046]
In the next place, a third embodiment of the present invention shown in FIGS. 7 and 8 will be described below.
[0047]
In the third embodiment, a catalyst support 17 is provided with a hollow-cylindrical partition tube 28 for partitioning a first catalyst chamber 25 and a second catalyst chamber 26 from each other, and a hollow-cylindrical partition wall 20 inside a first cap 18 is connected to one end of the partition tube 28. The other configurations are the same as in the second embodiment; therefore, in FIGS. 7 and 8, the portions corresponding to those in the second embodiment above are denoted by the same reference symbols as used above, and descriptions of them will be omitted. Naturally, the ratio A/B of the total volume A of the first and second catalyst chambers 25 and 26 to the volume B of a exhaust gas reversing chamber 23 is set in the same manner as in the first embodiment.
[0048]
According to the third embodiment, in the catalyst support 17, the first catalyst chamber 25 and the second
catalyst chamber 26 are securely partitioned from each other by the partition tube 28. Therefore, a forward flow of an exhaust gas passing through the first catalyst chamber 25 toward the exhaust gas reversing chamber 23 and a reverse flow of the exhaust gas passing through the second catalyst chamber 26 toward the exhaust gas discharging chamber 22 can be securely prevented from interfering with each other, thereby contributing to enhancement of engine output. [0049]
In the next place, a fourth embodiment of the present invention shown in FIGS. 9 and 10 will be described below. [0050]
In the fourth embodiment, a catalytic converter 10 includes: a hollow-cylindrical shell 16; a partition tube 28 integrally connected to a hollow-cylindrical partition wall 20 and concentrically disposed in the shell 16; catalyst supports 17A, 17B, and 17C formed of punching plate and joined respectively to the inner peripheral surface of the shell 16, the inner peripheral surface of the partition tube 28, and the outer peripheral surface of the partition tube 28; and a catalyst such as platinum, rhodium, palladium, etc. supported on the surfaces of the
catalyst supports 17A, 17B, and 17C. The partition tube 28 defines a first catalyst chamber 25 therein, whereas the shell 16 and the partition tube 28 define a hollow-cylindrical second catalyst chamber 26 surrounding the first catalyst chamber 25 by their fitting.
[0051]
The other configurations are the same as in the second embodiment; therefore, in FIGS. 9 and 10, the portions corresponding to those in the second embodiment above are denoted by the same reference symbols as used above, and descriptions of them will be omitted. Of course, in the fourth embodiment also, the ratio A/B of the total volume A of the first and second catalyst chambers 25 and 26 to the volume B of the exhaust gas reversing chamber 23 is set in the same manner as in the first embodiment.
[0052]
According to the fourth embodiment, the catalyst supports 17A, 17B, and 17C are each composed by use of a punching plate, whereby the catalytic converter 10 can be simplified in configuration, and can be reduced in cost.
[0053]
Finally, a fifth embodiment of the present invention shown in FIG. 11 will be described below.
[0054]
The fifth embodiment corresponds to a configuration in which an exhaust emission control device according to the second embodiment is disposed in an exhaust muffler 6 Specifically, the downstream end of an exhaust pipe 5 extending from an engine E (see FIG. 1) is connected to the front end of a hollow-cylindrical muffler body 30 of the exhaust muffler 6, and a tail pipe 31 opened into the atmosphere is attached to the rear end of the muffler body 30. The interior of the muffler body 30 is partitioned by a front-rear pair of partition wall plates 32 and 34 into three chambers, i.e., an intermediately disposed first silencing chamber 34, a front-side second silencing chamber 35, and a rear-side third silencing chamber 36, and a catalytic converter 10 with its both ends fronting on the first silencing chamber 34 and the second silencing chamber 35 is attached to a front-side partition wall 20.
[0055]
The structure of the catalytic converter 10 may be the same as that of any of the catalytic converters in the first to fourth embodiments above; in the embodiment shown here, the catalytic converter 10 in the second embodiment is used. Therefore, in FIG. 11, the portions
of the catalytic converter 10 which correspond to those in the second embodiment above are denoted by the same reference symbols as used above, and descriptions thereof will be omitted.
[0056]
The second silencing chamber 35 is provided therein with a hollow-cylindrical partition wall 20 integrally connected to the downstream end of the exhaust pipe 5 and facing the front end face of a catalyst support 17 of the catalytic converter 10, whereby the second silencing chamber 35 is partitioned into an exhaust gas introducing chamber 21 on the inner side of the partition wall 20 and an exhaust gas discharging chamber 22 on the outer side of the partition wall 20. Attendant on this, of the catalyst support 17, a multiplicity of passages communicating with the exhaust gas introducing chamber 21 form a first catalyst chamber 25, whereas a multiplicity of passages 24, 24, • • • communicating with the exhaust gas discharging chamber 22 form a second catalyst chamber 26 surrounding the first catalyst chamber 25.
[0057]
An exhaust gas having passed from the exhaust gas introducing chamber 21 through the first catalyst chamber 25 is reversed (turned back) in the first silencing
chamber 34, before flowing into the second catalyst chamber 26; therefore, the first silencing chamber 34 function as an exhaust gas reversing chamber. [0058]
A communicating pipe 37 for making the second silencing chamber 35 and the third silencing chamber 36 communicate with each other is attached to the two partition wall plates 32, 33. [0059]
The exhaust gas having passed through the second catalyst chamber 26 into the exhaust gas discharging chamber 22 passes through the communicating pipe 37 into the third silencing chamber 36, before being exhausted through the tail pipe 31 into the atmosphere. [0060]
By passing through the first and second catalyst chambers 25 and 26, the exhaust gas is clarified (undergoes emission control) in the same manner as in the above-described embodiments, and is silenced through repeating expansion stepwise. [0061]
According to the fifth embodiment, the compact catalytic converter 10 can be installed by utilizing a dead space inside the exhaust muffler 6. In addition, the
catalytic converter 10 can be heat-insulated (heat-retained) by the exhaust muffler 6, whereby early activation thereof can be effectively promoted, and the silencing effect can be more enhanced by the catalytic converter 10. [0062]
While the embodiments of the present invention have been described above, the invention is not limited to the above embodiments, and various design modifications are possible within the scope of the gist of the invention. [Description of Reference Symbols] [0064]
D: exhaust emission control device E: engine
5, 6: exhaust passage (exhaust pipe, exhaust muffler)
10: catalytic converter
21: exhaust gas introducing chamber
22: exhaust gas discharging chamber
23, 34: exhaust gas reversing chamber
25, 26: catalyst chamber
25: first catalyst chamber
26: second catalyst chamber
28: partition member (partition tube)




We Claim:
1. An exhaust emission control device for an engine, comprising a catalytic converter (10) intermediately disposed in an exhaust passage (5, 6) of said engine (E), wherein an exhaust gas introducing chamber (21) to which an upstream portion of said exhaust • passage (5, 6) is connected and an exhaust gas discharging chamber (22) to which a downstream portion of said exhaust passage (5, 6) is connected are formed at one end portion of said catalytic converter (10) to communicate, in parallel, with a catalyst chamber (25, 26) of said catalytic converter (10); an exhaust gas reversing chamber (23, 34) by which an exhaust gas having passed from said exhaust gas introducing chamber (21) through said catalyst chamber (25, 26) is guided again through said catalyst chamber (25, 26) into said exhaust gas discharging chamber (22) is formed at the other end portion of said catalytic converter (10) ; and the relationship of the following expression (1) as herein described, is established, where A is the total volume of said catalyst chamber (25, 26) and B is the volume of said exhaust gas reversing chamber (23, 34).
2. The exhaust emission control device for an engine as claimed in claim 1, wherein said catalyst chamber (25, 26) is partitioned into a first catalyst chamber (25) communicating with said exhaust gas introducing chamber (21) and a second catalyst chamber (26) communicating with said exhaust gas discharging chamber (22), and said first and second catalyst chambers (25, 26) are made to communicate with each other through said exhaust gas reversing chamber (23, 34).
3. The exhaust emission control device for an engine as claimed in claim 2, whrein said first catalyst chamber (25) and said second catalyst chamber (26) are so formed that one of them surrounds the other of them.
4. The exhaust emission control device for an engine as claimed in claim 2 or 3, wherein a partition member (28) for partitioning said first and second catalyst chambers (25, 26) from each other is disposed between said first catalyst chamber (25) and said second catalyst chamber (26).

5. The exhaust emission control device for an engine as claimed in any of claims 1 to 4, wherein said catalytic converter (10) is disposed directly under said engine (E).
6. The exhaust emission control device for an engine as claimed in any of claims 1 to 4, wherein said catalytic converter (10) is disposed in an exhaust muffler (6) included in said exhaust passage (5, 6).

Documents:

213-del-2007-Abstract-(08-04-2011).pdf

213-del-2007-abstract.pdf

213-del-2007-Claims-(08-04-2011).pdf

213-del-2007-claims.pdf

213-del-2007-Correspondence Others-(08-04-2011).pdf

213-del-2007-correspondence-others-1.pdf

213-del-2007-correspondence-others.pdf

213-del-2007-description (complete).pdf

213-del-2007-Drawings-(08-04-2011).pdf

213-DEL-2007-Drawings.pdf

213-del-2007-form-1.pdf

213-del-2007-form-18.pdf

213-del-2007-form-2.pdf

213-del-2007-Form-3-(08-04-2011).pdf

213-del-2007-form-3.pdf

213-del-2007-form-5.pdf

213-del-2007-GPA-(08-04-2011).pdf

213-del-2007-gpa.pdf

213-del-2007-Petition-137-(08-04-2011).pdf

abstract.jpg


Patent Number 248508
Indian Patent Application Number 213/DEL/2007
PG Journal Number 29/2011
Publication Date 22-Jul-2011
Grant Date 21-Jul-2011
Date of Filing 02-Feb-2007
Name of Patentee HONDA MOTOR CO., LTD.
Applicant Address 1-1, MINAMI-AOYAMA 2-CHOME MINATO-KU, TOKYO 107-8556, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 YOSHIHIKO KUMAGAI C/O HONDA R&D CO LTD., 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, 351-0193 JAPAN
2 NOBUHIRO SHIMADA C/O HONDA R&D CO LTD., 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, 351-0193 JAPAN
PCT International Classification Number F01N3/20
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2006-059924 2006-03-06 Japan