JPH08326528A - Exhaust pipe provided with exhaust emission control device - Google Patents

Abstract

PURPOSE: To attain desired exhaust gas purification without influencing engine output. CONSTITUTION: A perforated plate cylinder member 41 with a catalyst is disposed between the rear part of a divergent part 33 and the front part of a convergent part 35, and almost at the cross-sectional center of a straight member. Preliminary purifying reaction by high temperature gas is thereby attained at the top of the perforated plate cylinder member disposed at the divergent part 33, and proper purifying reaction can be attained at the remaining part of the perforated plate cylinder member disposed at the straight part and the convergent part 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe equipped with an exhaust gas purifying device suitable for motorcycles.

[0002]

2. Description of the Related Art A technique for mounting an exhaust gas purifying device on a vehicle for the purpose of preventing air pollution is known. For example, "Exhaust gas purifying device for internal combustion engine" in Japanese Patent Laid-Open No. 3-85320 is one of them. is there. As shown in FIG. 6 of the publication, this device has an inner pipe 5 with a catalyst arranged in a bent tubular exhaust pipe 3 directly below an engine to oxidize unburned components in exhaust gas.

[0003]

The inner tube 5 is a perforated plate and has a structure for promoting contact between the exhaust gas and the catalyst. Therefore, the flow of exhaust gas is necessarily disturbed. Moreover, since the inner pipe 5 is arranged in the bent tubular exhaust pipe 3 immediately below the engine, turbulence of the exhaust gas occurs immediately below the engine, which has a great influence on the output characteristics of the engine. This results in sacrificing engine output for exhaust gas purification, which is not desirable. Therefore, an object of the present invention is to provide a technique capable of achieving desired exhaust gas purification without affecting the engine output.

[0004]

In order to achieve the above-mentioned object, according to claim 1 of the present invention, a diver portion in which a flow passage cross-sectional area gradually increases in a gas flow direction and a straight portion in which the cross-sectional area is substantially constant. In the exhaust pipe of a two-cycle engine including an expansion chamber having a gradually decreasing cross-sectional area, a porous plate tubular member carrying a catalyst is provided from the rear portion of the diver portion to the front portion of the converting portion. It is characterized in that it is arranged between the above and substantially in the center of the cross section of the straight portion.

According to a second aspect of the invention, the perforated plate tubular member is characterized in that approximately one-third from the front and the rear end are supported by the front support stay and the rear stay.

According to a third aspect of the present invention, the perforated plate tubular member is supported by the front support stay and the rear support stay via an elastic material.

According to a fourth aspect of the present invention, the support stay has a structure for restricting the forward movement of the perforated plate tubular member, and the rear support stay has a structure for restricting the rearward movement of the perforated plate tubular member.

According to a fifth aspect of the present invention, the perforated plate tubular member is formed by rolling the perforated plate and welding the joints. The joints are held by the support stays so that the joints are upper or lower, and the support is also supported. It is characterized in that the stay is provided with a rotation stopping portion for the perforated plate tubular member to prevent the perforated plate tubular member from rotating.

According to a sixth aspect of the present invention, the exhaust pipe is formed by joining the divided pipe bodies to each other, and the perforated plate cylinder member is attached to one of the divided pipe bodies through the support stay.

[0010]

According to the present invention, the perforated plate tubular member carrying the catalyst is housed in the expansion chamber to suppress the turbulence of the gas flow. A preliminary purifying reaction with high-temperature gas is achieved at the top of the perforated plate tubular member arranged in the diver part, and a full-scale purifying reaction is carried out in the remaining straight part and the rest of the perforated plate tubular member arranged in the convertor part.

According to the second aspect of the present invention, approximately 1/3 of the perforated plate tubular member and its rear end are securely supported by the front support stay and the rear stay. The top of the perforated plate tubular member which becomes hot can be freely expanded and contracted forward while being supported in a cantilever manner.

In the third aspect, the space between the front support stay and the rear support stay of the perforated plate tubular member is freely expanded and contracted.

In the fourth aspect, the movement of the perforated plate tubular member in the front-rear direction is appropriately limited to prevent the same from coming off.

In the present invention, the rotation of the perforated plate cylinder member is suppressed. Since the mating part formed by rolling the perforated plate and welding the mating part is always in a fixed position, the condition for strength design of the mating part is determined.

In the sixth aspect, it is possible to form a small set in which the perforated plate tubular member is attached to one of the divided pipe bodies via the support stay.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a side view of a motorcycle equipped with an exhaust pipe according to the present invention. The motorcycle 1 pivotally supports a front fork 4 on a front portion of a main frame 2 via a head pipe 3, and the front fork 4 is attached to the front fork 4. The front wheel 5 and the front fender 6 are attached, the engine 8 is attached below the main frame 2,
An exhaust pipe 30 extends from the engine 8, a swing arm 11 extends from a rear end of the main frame 2 via a pivot 9, and a rear wheel 12 is attached to the swing arm 11. In the figure, 14 is a fuel tank, 15 is an air filter, 16 is a carburetor, 17 is a seat, 18 and 19 are seat rails, 21 is a rear suspension, 22 is a drive chain, and 23 is a silencer.

FIG. 2 is a side view of an exhaust pipe provided with the exhaust gas purifying apparatus according to the present invention. The exhaust pipe 30 has a bent tubular exhaust pipe portion 31 and an expansion chamber 32.
Reference numeral 2 denotes a diver portion 33 whose flow passage cross-sectional area gradually increases in the gas flow direction and a straight portion 34 having a substantially constant cross-sectional area.
And a convertor portion 35 whose cross-sectional area gradually decreases. The exhaust pipe is an abbreviation for an exhaust pipe, but here it indicates only the bent pipe immediately below the engine, not the entire exhaust pipe. Diver is an abbreviation for diver jet,
Convert is an abbreviation for converge jet.

The exhaust pipe 30 has a built-in exhaust gas purifying device 40, and a perforated plate tubular member 41 with a catalyst, which is a main element of the exhaust gas purifying device 40, is provided from the rear part of the diver part 33 to the front part of the convertor part 35. It is characterized in that it is arranged between the portions and in the substantially central section of the straight portion 34 (see also FIG. 3). 37 is a hanging metal fitting.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2, showing the structure of the front support stay. The front support stay 42F is W
The support ring 43F includes a letter-shaped support metal fitting 43F and an outer ring 44 welded to the support metal fitting 43F. The outer ring 44 is vertically divided into two for convenience of assembly. The elastic member 45 supported by the outer ring 44, the inner ring 46, and the perforated plate tubular member 41 will be described later.
The exhaust pipe 30 is formed by combining the divided pipe body 30R and the divided pipe body 30L, and shows that the W-shaped support fitting 43F is fixed to only one divided pipe body 30R by welding. As is apparent from the figure, the perforated plate tubular member 41 is held at the approximate center of the cross section of the exhaust pipe 30 by the supporting action of the front support stay 42F. The rear support stay (42R) basically has the same structure as the front support stay 42F except that the shape of the W-shaped support bracket (43R) is slightly different.

FIG. 4 is an exploded perspective view of the rear portion of the exhaust gas purifying apparatus according to the present invention.
A cylindrical body is formed by making a notch 41b at the rear end of 1a, rounding it so that the notch 41b becomes the bottom, and welding the upper mating portion 41c. A noble metal or ceramics as a catalyst is supported on the porous plate tubular member 41. Further, an inner ring 46 having a collar 46a is covered on the rear portion of the perforated plate tubular member 41 and welded. The inner ring 46 may be a divided body. The heat resistant elastic material 45 is fitted to the inner ring 46, and the elastic material 45 is held by the outer ring 44 divided into two. The outer ring 44 has a thrust stop collar 44a, and the lower outer ring 44 has a rotation stop portion 44b. The rotation stop portion 44b is fitted in the notch 41b at the rear end of the perforated plate tubular member 41. To stop rotation of the perforated plate cylinder member 41. The elastic material 45 is preferably stainless wool having heat resistance and cushioning properties.

FIG. 5 is a plan sectional view of the exhaust gas purifying apparatus according to the present invention.
The small hole 41d cannot be opened in the portion overlapping with 6 and 46. This is because exhaust gas cannot pass through because it is covered with the inner ring 46. When the total length of the perforated plate tubular member 41 is L, the position 1 / 3L from the front end is the mounting position of the front support stay 42F.

The front support stay 42F has an outer ring 44.
The elastic body 4 is composed of the collar 44a of the inner ring 46 and the collar 46a of the inner ring 46.
Similarly, the rear support stay 42R includes the collar 44a of the inner ring 44 and the collar 4 of the outer ring 46.
The elastic body 45 is sandwiched between the elastic body 45 and the 6a, and the collar 44a of the outer ring 44 of the front support stay 42F is formed of the elastic body 4a.
5 restricts the forward movement (left in the figure), and the rear support stay 4
The elastic body 45 of the collar 44a of the 2R outer ring 44 restricts the rearward movement (right side in the drawing).

FIG. 6 is a view taken in the direction of arrow 6-6 in FIG. 5, showing a main part of the rear support stay 42R, in which the rotation stop piece 44b of the outer ring 44 is fitted in the notch 41b of the perforated plate tubular member 41. Indicates that For this reason, the perforated plate tubular member 41 does not rotate. 41c is a joining part. FIG. 7 shows 7- of FIG.
FIG. 7 is a sectional view taken along line 7 and shows that the perforated plate tubular member 41 is supported by the outer ring 44 of the front support stay 42F via the elastic body 45 and the inner ring 46.

A method of assembling the exhaust pipe having the above structure will be described below. FIG. 8 is an assembly procedure diagram of the exhaust pipe according to the present invention. As shown in FIG. 4, the outer ring 44 is assembled at a position ⅓L from the front end of the perforated plate tubular member 41, and at the same time, the perforated plate tubular member 41 is assembled. Assemble the outer ring up to the rear part. Outer rings 44, 44 as indicated by the arrow
Attach the W-shaped support metal fittings 43F and 43R to
As indicated by the arrow, W-shaped support metal fittings 43F, 43R
Is attached to one of the split tubes 30R. After this, the other split tube body 30L is attached as indicated by the arrow. With this, the exhaust gas purifying device 40 is incorporated in the expansion chamber 32 of the exhaust pipe 30 shown in FIG.

Next, the operation of the exhaust pipe provided with the exhaust gas purifying device will be described. In FIG. 1, the hot exhaust gas from the engine 8 passes through the inside of the exhaust pipe 30 and the silencer 2 at the rear side.
Up to 3. At this time, in FIG. 2, the exhaust gas can first achieve a preliminary purification reaction with high-temperature gas at the top of the perforated plate tubular member 41 arranged in the diver section 33, and then the porous gas arranged in the straight section 34 and the convertor section 35. Plate cylinder member 41
A full-scale purification reaction can be achieved with the rest of the.

In FIG. 5, a portion 1 / 3L from the front end and the rear end of the perforated plate tubular member 41 are reliably supported by the front support stay 42F and the rear support stay 42R. The top of the perforated plate tubular member 41, which has a high temperature, freely expands and contracts forward while being supported in a cantilever manner. The elastic members 45, 4 are also provided between the front support stay 42F and the rear support stay 42R of the porous plate tubular member 41.
By the action of 5, it expands and contracts freely.

However, in order to prevent the perforated plate tubular member 41 from coming off from the front support stay 42F and the rear support stay 42R, the perforated plate tubular member 41 is secured by the flanges 44a and 44a of the outer rings 44 and 44 facing each other. The movement in the front-rear direction is appropriately limited to prevent the member 41 from coming off. Further, the rotation stopping portion 44b suppresses the rotation of the porous plate tubular member 41. The perforated plate 41a is rolled, and the mating part 41c is welded, so that the mating part is always in a fixed position.
This is convenient because the conditions for strength design are determined.

FIG. 9 is a view showing another embodiment of the exhaust pipe according to the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals and their detailed description will be omitted. The exhaust pipe 30 has an exhaust gas purifying device 40 built in an expansion chamber 32 and has a bent tubular exhaust pipe portion 3.
1 is lined with a heat insulating material 51. 52 is a restraining plate. The exhaust gas purification reaction becomes more active as the temperature of the catalyst rises. Therefore, the exhaust section 31 has a heat insulating structure,
The temperature drop of the exhaust gas in this portion is suppressed as much as possible, and the high temperature exhaust gas is guided to the exhaust gas purification device 40.

Although the exhaust pipe of the motorcycle has been described in the present embodiment, the exhaust pipe 30 of the present invention may of course be applied to the exhaust pipe of other internal combustion engines.

[0030]

The present invention has the following effects due to the above configuration. In the first aspect, since the perforated plate tubular member supporting the catalyst is housed in the expansion chamber, the turbulence of the gas flow can be suppressed, so that the influence on the output of the engine can be minimized. Then, a preliminary purification reaction with high-temperature gas is achieved at the top of the perforated plate cylinder member arranged in the diver part, and a full-scale purification reaction is carried out with the remaining straight part and the rest of the perforated plate cylinder member arranged in the convertor part. Therefore, effective purification can be achieved.

In the second aspect of the invention, approximately 1/3 of the perforated plate tubular member from the front and the rear end are reliably supported by the front support stay and the rear stay. The top of the perforated plate tubular member which becomes hot can be freely expanded and contracted forward while being supported in a cantilever manner.

According to the third aspect of the invention, the space between the front support stay and the rear support stay of the perforated plate tubular member is freely expanded and contracted by the action of the elastic material.

In the fourth aspect, the movement of the tubular member of the perforated plate in the front-rear direction is appropriately limited to prevent the member from coming off.

In the fifth aspect, the rotation of the perforated plate cylinder member is suppressed. Since the mating part formed by rolling the perforated plate and welding the mating part is always in a fixed position, the condition for strength design of the mating part is determined.

In the sixth aspect, it is possible to form a small set in which the perforated plate tubular member is attached to one of the divided pipe bodies via the support stay.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle equipped with an exhaust pipe according to the present invention.

FIG. 2 is a side view of an exhaust pipe equipped with an exhaust gas purification device according to the present invention.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is an exploded perspective view of a rear portion of the exhaust gas purification device according to the present invention.

FIG. 5 is a plan sectional view of an exhaust gas purifying apparatus according to the present invention.

6 is a view on arrow 6-6 of FIG.

7 is a sectional view taken along line 7-7 of FIG.

FIG. 8 is an assembly procedure diagram of an exhaust pipe according to the present invention.

FIG. 9 is a view showing another embodiment of the exhaust pipe according to the present invention.

[Explanation of symbols]

1 ... Motorcycle, 8 ... Engine, 30 ... Exhaust pipe, 30
R, 30L ... Split tube body, 31 ... Exhaust section, 32 ... Expansion chamber, 33 ... Diver section, 34 ... Straight section, 35 ... Conver section, 40 ... Exhaust gas purifying device, 41 ... Perforated plate tubular member, 41b ... Cut , 41c ... Fitting portion, 42F ... Front support stay, 42R ... Rear support stay, 43F, 43R ...
W-shaped support metal fittings, 44 ... Outer ring, 44a ...
Tsuba, 44b ... Rotation stop portion, 45 ... Elastic material, 46 ... Inner ring, 46a ... Tsuba.

Claims (6)

[Claims] 1. An expansion chamber comprising a diver portion whose flow passage cross-sectional area gradually increases in the gas flow direction, a straight portion whose cross-sectional area is substantially constant, and a convertor portion whose cross-sectional area gradually decreases. In the exhaust pipe of a two-cycle engine,
This exhaust pipe is a porous plate tubular member carrying a catalyst, between the rear part of the diver part and the front part of the convertor part,
An exhaust pipe provided with an exhaust gas purifying device, which is arranged substantially in the center of the cross section of the straight portion. 2. The perforated plate cylinder member is about 1 / about from the front.
An exhaust pipe provided with the exhaust gas purifying apparatus according to claim 1, wherein the three points and the rear end are supported by a front support stay and a rear stay. 3. The exhaust pipe provided with the exhaust gas purifying apparatus according to claim 2, wherein the perforated tube member is supported by the front support stay and the rear support stay via an elastic material. . 4. The front support stay limits the forward movement of the porous plate tubular member, and the rear support stay limits the backward movement of the porous plate tubular member. An exhaust pipe provided with the exhaust gas purification device according to 3. 5. The perforated plate cylinder member is formed by rolling a perforated plate,
The mating portion is welded, and the mating portion is held by the support stay so that the mating portion is positioned above or below, and the rotation stop portion of the perforated plate tubular member is attached to the support stay to prevent the perforated plate tubular member from rotating. An exhaust pipe provided with the exhaust gas purification device according to claim 1, wherein 6. The exhaust gas according to claim 1, wherein the exhaust pipe is formed by joining divided pipes to each other, and a perforated plate cylinder member is attached to one of the divided pipes via a support stay. Exhaust pipe with purification device.