JP3276117B2 - Exhaust silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust muffler having a built-in catalyst for purifying exhaust of an engine.

[0002]

2. Description of the Related Art There is known an exhaust silencer including a catalyst for purifying exhaust gas of an internal combustion engine. Since the temperature of the catalyst becomes high due to the chemical reaction, the temperature of the entire exhaust silencer generally becomes very high. For this reason, conventionally, not only the partition plate in the exhaust silencer but also the entire case including the outer case is made of a stainless steel plate having excellent heat resistance.

[0003]

However, there is a problem that materials having high heat resistance such as stainless steel are generally heavy and expensive.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and when a catalyst which becomes high in temperature is incorporated, a material having low heat resistance can be partially used to increase the degree of freedom in material selection. It is another object of the present invention to provide an exhaust silencer suitable for weight reduction and cost reduction.

[0005]

According to the present invention, there is provided an outer case in which openings at both front and rear ends of an outer cylinder are closed by a pair of end plates ;
A partition plate made of a material having higher heat resistance than the outer case and defining a plurality of expansion chambers in the outer case;
Made of a material with higher heat resistance, the front end plate
An exhaust pipe that movably and airtightly penetrates, penetrates at least one partition plate, and introduces exhaust gas into the rearmost expansion chamber ; and an exhaust purification catalyst body held in the exhaust gas inlet pipe ; Made of a material having higher heat resistance than the outer case,
The rearmost bulge is placed so that the reflective surface faces the rear end of the exhaust pipe
Located in the upholstery room and fixed to the rear end plate at an interval
Reflector and a material with higher heat resistance than the outer case
Made, penetrate at least one partition plate, and
With a pipe that communicates with the outer case;
Made, axially movable through the rear end plate and airtightly penetrated
Then, the exhaust gas purified through the exhaust gas purifying catalyst is expanded.
An exhaust outlet pipe for discharging the exhaust from the tension chamber to the outside .

[0006]

1 is a side view of a motorcycle to which an embodiment of the present invention is applied, FIG. 2 is a plan view of the same, FIG. 3 is a rear view, and FIG.
Is a side view showing the appearance.

[0007] Reference numeral 10 denotes a vehicle body frame,
One main tube 14 and one down tube 16 extending obliquely backward from the rear, and a pair of left and right seat pillar tubes 18 and 1 descending from the rear end of the main tube 14.
8, a pair of left and right lower tubes 22, 22 gathering with the seat pillar tubes 18, 18 by a pivot bracket 20 extending downward and rearward from the down tube 16, and a pair of left and right seat rails 2 extending rearward from the main tube 14.
4 and a pair of left and right back tubes 26, 26 connecting the pivot bracket 20 and the seat rail 24.

A front wheel 30 is attached to lower ends of a pair of front forks 28, 28 held by the steering barrel 12, and a steering handlebar 32 is attached to upper ends of the front forks 28, 28. Reference numerals 34, 34 denote a pair of left and right rear arms, the front end of which is pivotally supported by the pivot bracket 20, and the rear wheel 36 held at the rear end.

A cushion unit 38 elastically supports the rear wheel 36. The upper end of the cushion unit 38 is pivotally supported by the rear end of the main tube 14, while the lower end is connected to the rear arm 34 via a link mechanism 40.

The link mechanism 40 includes a lower arm 2
A first link 42 whose front end is pivotally supported and whose rear end can swing up and down, between the first link 42 and the rear arm 3;
4 and a pair of second links 44 connecting the second link 4 and the lower end of the cushion unit 38 to the rear end of the first link 42.

Reference numeral 46 denotes a single-cylinder liquid-cooled two-stroke engine, which is mounted between the lower tube 22 and the seat pillar tube 18. The output of the engine 46 is transmitted to the rear wheel 36 via a chain 48.

The engine 46 has a cylinder 50 which rises obliquely and upward, and a carburetor 52 is connected to a rear surface thereof. A first air cleaner 54 is disposed between the left and right back tubes 26 behind the cushion unit 38. The first air cleaner 54 and the carburetor 52 are connected to the duct 5 that bypasses the left side of the cushion unit 38.
6 are connected. The first air cleaner 54 contains an element.

Reference numeral 58 denotes a second air cleaner, and the rear wheel 36
It is arranged on the upper left side of. That is, the second air cleaner 58 is suspended outside the left seat rail 24, and its lower part is held by a side bar 60 connecting the left back tube 26 and the rear part of the seat rail 24.

The second air cleaner 58 is connected to an air intake box 64 provided integrally with a rear body cover 62 made of resin.
, And sucks the outside air through a duct 6.
6 leads to the first air cleaner 54. Here, the intake box 64 has an outside air intake 70 opening below a tail light 68 projecting substantially horizontally rearward from the rear portion of the rear body cover 62 to make it difficult to draw rainwater, snow, etc. 36 makes it difficult for muddy water to splash.

In the second air cleaner 58, a bent air flow path is formed by an appropriate number of walls 59, and a rubber cap 72 is mounted at an appropriate position. The rubber cap 72 is detachable, and by removing the rubber cap 72, it is possible to remove snow that accumulates in the air flow path during traveling in snow.

An exhaust pipe 74 is connected to the front of the cylinder 50. The exhaust pipe 74 extends forward and downward from the cylinder 50, makes a half turn in the counterclockwise direction, and then extends upward. Then, it extends rearward through the right side of the cushion unit 38 via an inflation pipe portion located on the upper right side of the cylinder 50, and is connected to the exhaust silencer 76. The structures of the exhaust pipe 74 and the exhaust silencer 76 will be described later.

The exhaust silencer 76 is disposed on the upper right side of the rear wheel 36. That is, the silencer 76 has a vertically long elliptical cross section, and its upper part is attached to the right seat rail 24 and its lower part is the right back tube 2.
3 and the side bar 78 (FIG. 3)
See).

The second air cleaner 58 and the silencer 76
The entire side is covered with the rear vehicle body cover 62, and the tail pipe of the muffler 76 projects rearward through the rear vehicle body cover 62. In this embodiment, a sound insulating plate 80 is mounted between the rear wheel 36 and the second air cleaner 58, and a heat insulating plate 82 is mounted between the rear wheel 36 and the muffler 76 (FIG. 3).

Therefore, the intake noise of the second air cleaner 58 is hardly leaked to the outside, and it is also suitable for keeping the heat of the silencer 76 and insulating the sound. In particular, when the silencer 76 is provided with an exhaust gas purification measure such as a catalyst, the purifying action can be promoted by keeping the temperature of the silencer 76 constant. Also silencer 76
To the rear wheel 36 to increase the capacity of the silencer 76. The sound insulation plate 80 and the heat insulation plate 82 have a shape that fills a substantially rhombic opening surrounded by the back tube 26, the seat rail 24, and the side bars 60 and 78.

Reference numeral 84 denotes a vertically long radiator with an electric fan, which is vertically mounted on the left rear side of the steering barrel 12.
The coolant of the engine 46 circulates through the radiator 84. 86 is a fuel tank. The fuel tank 86 is attached so as to straddle the main tube 14, and a concave portion 88 for accommodating the radiator 84 is formed on the left front lower surface thereof.

Reference numeral 90 denotes a resin front vehicle body cover which covers the fuel tank 86, the radiator 84, and the vicinity of the cylinder 50 from around the steering barrel 12. Here, above the steering handlebar 32, there is a tank cover 92 that can be opened and closed upward, which is opened to supply fuel. Reference numeral 94 denotes a resin side cover that covers the side of the engine 46 and the vicinity of the pivot bracket 20 from the front of the cylinder 50.

Reference numeral 96 denotes a removable resin intermediate cover which covers the side of the vaporizer 52. In the intermediate cover 96, an exhaust port 98 for guiding the traveling wind passing through the radiator 84 to the outside is open rearwardly. Adjustment of the carburetor 52 can be performed from the outside through the exhaust port 98. By removing the intermediate cover 96, maintenance around the carburetor 52 can be easily performed.

A lower cover 100 is formed in a substantially bowl shape so as to cover a lower portion of the engine 46. The lower cover 100 is made of a metal such as an aluminum plate having excellent impact resistance, and its front portion covers the lower front portion of the exhaust pipe 74 from below, while its rear portion extends to below the link mechanism 40.
0 is protected from obstacles on the road surface.

The lower edge of the side cover 94 is smoothly fixed to the lower cover 100 to increase the mounting strength of the side cover 94. These covers 90, 92, 9
4, 96 and 100 surround the engine 46 and prevent engine noise from leaking out.

Reference numeral 102 denotes a straddle-type operation seat which is long in the front and rear direction and is located on the rear of the engine 46 on the upper side thereof, and is attached to the seat rail 24. The front portion of the operation seat 102 smoothly continues to the front vehicle body cover 90, and the rear portion and side edges smoothly continue to the rear vehicle body cover 62. 1
04 is a pair of left and right footrests.

Next, the structure of the exhaust pipe 74 will be described with reference to FIG. This exhaust pipe 74 has three pieces (parts) I, II,
III are connected together. The connecting portion 110 connected to the cylinder 50 is fixed to the piece I, and the inner surface of the connecting portion 110 is exposed to high-temperature exhaust gas, so that it has a multilayer structure.

That is, the piece I has a double structure including an outer plate 112 made of a steel plate and an inner plate 114 made of a steel plate in close contact with the outer plate 112. On the inner surface of the inner plate 114, a cloth catalyst 116 and a punching metal 118 are further laminated. Here punching metal 118 is a stainless steel plate provided with many small holes, a metal catalyst such as platinum-rhodium (P _t / P _h) system is supported on the surface thereof.

The pieces II and III are provided with a sound absorbing material 122 such as glass wool in place of the inner plate 114 of the piece I. The outer plate 112 and the sound absorbing material 12 are provided.
2. It has a laminated structure of cloth catalyst 116 and punching metal 118. The catalyst provided in the exhaust pipe 74 has a function of purifying the exhaust gas, keeping the exhaust gas warm, and promoting a catalytic reaction in the exhaust silencer 76.

Next, the structure of the exhaust silencer 76 will be described with reference to FIGS. FIG. 6 is a side sectional view of the exhaust silencer 76, and FIG.
Is a sectional view taken along the line VII-VII. 130 in these figures
Is an outer case made of an aluminum plate. This outer case 1
Reference numeral 30 denotes an outer cylinder 132 having an elliptical cross section, and a pair of end plates 134 and 136 for closing both ends of the outer cylinder 132. Outer cylinder 1
32 can be made by welding left and right split members together. The aluminum end plates 134 and 136 each have a flange portion formed along the outer periphery thereof. After a partition plate described later is housed in the outer cylinder 132, the aluminum end plates 134 and 136 are press-fitted into the outer cylinder 132 from both sides. Aluminum welding is performed over the circumference.

Reference numerals 138 and 140 are partition plates made of a stainless steel plate. These partition plates 138 and 140 have a flange portion formed along the outer periphery, and after being press-fitted into the outer tube 132, the flange portion is fixed to the outer tube 132 by rivets 142 (FIG. 7).

An exhaust pipe 142 projecting toward one end plate 134 is fixed to the partition plates 138 and 140. This exhaust introduction pipe 142 is made of stainless steel,
It has a small diameter portion 144, a conical tube portion 146, and a large diameter portion 148. The small diameter portion 144 and the conical tube portion 146 are welded, and the conical tube portion 146 and the large diameter portion 148 are connected by press fitting. The large-diameter portion 148 is welded to one partition plate 138 and press-fitted into the other partition plate 140.

A cylindrical member 150 made of aluminum is penetrated and welded to the one end plate 134, and a small diameter portion 144 is inserted through the cylindrical member 150 so as to be movable in the axial direction. O-rings 152, 152 for hermetically sealing the space between the cylindrical member 150 and the small-diameter portion 144 are mounted. Therefore, the large-diameter portion 148 is used alone as the partition plate 138, 140.
And fixed to the partition plate 138 by welding.
With the cylindrical member 150 and the end plate 134 attached to the small-diameter portion 144, a conical tube portion 146 integral with the small-diameter portion 144 is press-fitted into the large-diameter portion 148. Thereafter, the end plate 134 is pressed into the outer cylinder 132 and welded.

The end plate 134 and the small diameter portion 144,
Prior to the assembly of the conical tube portion 146, the partition plates 138, 1
The pipe 154 penetrates the partition plate 138, the pipe 156 penetrates the partition plate 138, and the other end plate 136 penetrates the partition plate 140.
Pipes 158 as exhaust exhaust pipes extending to the sides are fixed respectively. Here, each pipe 154, 156, 158
The partition 138 and the partition plates 138 and 140 are fixed by welding except that the pipe 154 and the partition plate 140 are press-fitted. These pipes 154, 156, 158 are all a partition plate 138,
It is made of the same stainless steel as 140.

The large diameter portion 148 penetrates through the partition plates 138 and 140 and is welded to one partition plate 138 and the other partition plate 138.
It is press-fitted into the 40. A monolithic catalyst body 160 for purifying exhaust gas is mounted inside the large diameter portion 148. The catalyst body 160 has a catalyst supported on the surface of a carrier 162 which is an integrally formed product made of ceramic or heat-resistant steel foil having a large number of gas flow holes (cells), and the outer periphery thereof is surrounded by a holding material 164. . The holding material 164 expands when heat is applied and presses the large diameter portion 148 and the carrier 162, thereby fixing the carrier 162 in the large diameter portion 148.

A cylindrical member 166 through which a pipe 158 is inserted is fixed to the end plate 136, and a reflection plate 168 is attached at a position facing the large diameter portion 148. Here, the cylindrical member 166 is made of the same aluminum material as the end plate 136, and is fixed to the end plate 136 by welding. Also, the reflection plate 168
A stainless steel wire mesh 172 is loaded into a substantially dish-shaped stainless steel case 170, and is held by a stainless steel punching metal 174. The back surface of the case 170 of the reflection plate 168 is made of stainless steel. Is riveted to the end plate 136 at an interval from the end plate 136 by a bracket 176 made of stainless steel.

Accordingly, the end plate 136 is connected to the cylindrical member 166.
The pipe 158 is inserted into the outer cylinder 1 while moving in the axial direction.
32, and the flange portion on the outer periphery of the end plate 136 is fixed to the outer cylinder 132 by welding. O-rings 178 and 178 are mounted on the inner periphery of the cylindrical member 166 to contact the outer periphery of the pipe 158 and hermetically seal the same.

According to this embodiment, the exhaust gas is guided from the exhaust pipe 74 to the small diameter section 144 of the exhaust introduction pipe 142,
Oxidation / reduction reaction is performed by the catalyst body 160 in 48, and the catalyst enters the expansion chamber 180 on the end plate 136 side. In the expansion chamber 180, the exhaust collides with the reflector 168 and is inverted. The high-temperature exhaust gas that has undergone the catalytic reaction does not directly collide with the end plate 136, so that the end plate 136 can be protected from heat and the punched metal 1
The vibration of the end plate 136 due to the exhaust vibration can be prevented by effectively utilizing the heat absorption / sound absorption effect of the wire 74 and the wire mesh 172.

The exhaust gas reflected by the reflecting plate 168 is guided by a pipe 154 to an expansion chamber 182 on the side of the end plate 134, and is further separated by a pipe 156 into partition plates 138 and 140.
Into the expansion chamber 184. The exhaust pulsation is suppressed while the expansion is repeated in this manner, and the noise is reduced. Finally, it is discharged outside by a pipe 158 as an exhaust outlet pipe.

In the above embodiment, two partition plates are provided.
The present invention includes one or three or more of them. The reflector 168 may be an independent reflector as in the embodiment, but may be two or more, and one of the partitions may be used as a reflector.

[0040]

As described above, according to the present invention, an outer case is formed by an outer cylinder and a pair of front and rear end plates, and a partition plate having high heat resistance is provided in the outer case. The pipe can be moved axially through one (front side) end plate ,
Causes through, at least held by penetrating a partition plates, while holding the catalyst to the exhaust inlet tube, the exhaust end plate of the other (rear) made of highly heat-resistant material To
From now on, the light is reflected by hitting a fixed reflecting plate at an interval, and the other (rear side) end plate is movable in the axial direction and is airtight.
The gas is exhausted to the outside by a heat-resistant exhaust outlet pipe that penetrates .

That is, the exhaust gas introduction pipe for holding the catalyst body which is heated to a high temperature is made of a material such as stainless steel having high heat resistance, and this is similarly held on a partition plate having high heat resistance.
The reflector is also made of a material with high heat resistance and this is attached to the rear end plate.
Since the outer case is fixed at an interval, a material such as aluminum having lower heat resistance than the above can be used for the outer case. Therefore, the outer case and the other members can be made of different materials, and the degree of freedom of material selection is expanded. In addition, weight reduction and cost reduction can be achieved by appropriate material selection.

[Brief description of the drawings]

FIG. 1 is a side view of a motorcycle to which one embodiment of the present invention is applied.

FIG. 2 is a plan view thereof.

FIG. 3 is a rear view

FIG. 4 is a side view showing the appearance.

FIG. 5 is a diagram showing a structure of an exhaust pipe.

FIG. 6 is a side sectional view of the exhaust silencer.

FIG. 7 is a sectional view taken along the line VII-VII.

[Description of Signs] 76 Exhaust silencer 130 Outer case 132 Outer cylinder 134, 136 End plate 138, 140 Partition plate 142 Exhaust introduction pipe 154, 156 Pipe 158 Pipe 160 as exhaust outlet pipe 160 Catalyst 168 Reflector 180, 182, 184 expansion chamber

Claims (1)

(57) [Claims] Defining a plurality of expansion chambers in heat resistance than said outer casing is made of high material within said outer casing; that claim 1 outer case and the opening of the front and rear ends formed by closed by a pair of end plates of the outer cylinder A partition plate ; made of a material having higher heat resistance than the outer case, and a front end
Exhaust gas is introduced into the rearmost expansion chamber while passing through the plate in an axially movable and airtight manner and through at least one partition plate.
Exhaust introduction pipe to the; this is held in the exhaust gas introduction pipe was an exhaust purifying catalytic member; heat resistance than said outer casing is made of high material, the exhaust
The rearmost expansion chamber so that the reflective surface faces the rear end of the inlet tube
And fixed to the rear end plate at a certain distance
Reflector made of a material having higher heat resistance than the outer case, at least
Also penetrates one partition plate and connects the expansion chambers
And; made of a material having higher heat resistance than the outer case, and a rear end
The plate is movable in the axial direction and penetrates airtightly, and the exhaust gas is purified.
Exhaust gas that has been purified through the catalyst
An exhaust exhaust pipe for discharging the exhaust gas.