JP3277801B2 - Exhaust gas purification device - 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 gas purifying apparatus for purifying exhaust gas exhausted from an engine of a motorcycle or the like.

[0002]

2. Description of the Related Art Catalysts for purifying engine exhaust gas include plate type, pipe type and other types.
Each of them is provided inside a muffler connected to an exhaust pipe extending from an engine exhaust port, and is attached to the muffler as follows.

The first is disclosed in Japanese Patent Application Laid-Open No. 4-109022. As shown in FIGS. 8 and 9, both ends of a plate-shaped catalyst a are bent and the bent portion b is muffled. c is fixed to the inner wall. Part 2 is shown in FIG.
As shown in FIG. 11, flanges e are formed at both ends of a pipe-shaped catalyst d, and the flanges e are fixed to the inner wall of the muffler f. Third, as shown in FIGS. 12 and 13, a pipe-shaped catalyst i is connected to a stay j through a ring-shaped wire mesh g in which a large number of wires are meshed and a reinforcing plate h provided on the outer periphery thereof. Held by
Both ends of the stay j are fixed to the inner wall of the muffler k. No. 4 is disclosed in Japanese Patent Application Laid-Open No. 49-109718. As shown in FIG. 14, elasticity is provided in the gap between the outer peripheral surface of the integral catalyst 1 having a circular cross section and the inner peripheral surface of the muffler m. Filled with a ceramic fiber n and a foamed ceramic o having heat insulation.

[0004]

In the first and second prior arts, the catalysts a and d are fixed to the mufflers c and f by welding, or are held by metal. The amount of heat transferred to c and f is large, so that it takes time for the temperature rise of the catalysts a and d to take time in the early stage of operation in the cold state, and it takes time for the catalytic reaction to occur,
There has been a problem that the exhaust gas is not purified for a relatively long time. Also, catalysts a and d reach a certain temperature,
After the start of the catalytic reaction, the heat of the catalyst is easily transmitted to the muffler, and the muffler becomes high in temperature, so that heat damage countermeasures such as cowling are required, resulting in an increase in cost. Further, since the vibrations of the vehicle or the engine are easily transmitted to the catalysts a and d, the catalyst may peel off. In addition, it is necessary to increase the thickness of the catalyst in order to improve the strength. Increased costs and costs.

[0005] In the third conventional example, since the catalyst i is fixed to the muffler k via the wire mesh g, the above-mentioned problem is relatively rare, but the support point is only one. In addition, since it is only floating support via the wire mesh g, it is not sufficient to fix the catalyst i. In the fourth conventional example, heat insulation between the catalyst l and the muffler m is performed by the foamed ceramic o. However, since almost the entire outer peripheral surface of the catalyst l is fixed to the muffler m via the foamed ceramic o, 2 at both ends of foamed ceramic 0
Only the ceramic fiber n provided at the location or in addition to the three locations provided between both ends is not enough to absorb the vibration from the vehicle or the like. The present invention has been made in view of the above problems, and it is an object of the present invention to provide an exhaust gas purifying apparatus capable of improving purification performance and durability of a catalyst and reducing costs.

[0006]

According to the present invention, in order to achieve the above object, an under cowl is provided on a side of an engine.
Is, first muffler is connected to an exhaust port of the engine, said first
Pie with precious metal catalyst coated inside muffler
The catalyst is provided in the form of a loop , and its longitudinal direction is the first mask.
From the inner wall of the first muffler approximately along the hula axis
Exhaust gas purification supported by stays at regular intervals
In the apparatus, the exhaust gas purifying apparatus outside of the catalyst
Tighten the insulation material arranged on the peripheral surface with the clamp of the reinforcing plate
A float holding the catalyst at the bent portion of the stay via the heat insulating material
Dynamic support point , after fixing the reinforcing plate on the peripheral surface of the catalyst
A fixed support point where the reinforcing plate is welded to the bent portion of the stay.
And the floating support portion is provided with an engine exhaust of the first muffler.
It is characterized in that the position is set on the mouth side .

In the present invention, since at least one point of the catalyst is supported via the heat insulating material, the amount of heat transferred from the catalyst to the muffler is small.
The time until the catalytic reaction starts is relatively short. In addition, the reaction heat of the catalyst is not easily transmitted to the muffler, so that it is not necessary to take measures against heat damage such as cowling.

On the engine exhaust side, the exhaust gas is at a high temperature and the reaction with the catalyst is more intense, so that the reaction heat of the catalyst becomes higher. However, a floating support position is provided on the engine exhaust side. Therefore, it is difficult for high-temperature catalytic reaction heat to be transmitted to the muffler.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an exhaust gas purifying apparatus according to the present invention will be described below with reference to the drawings. FIG.
FIG. 1 shows an overall side view of a motorcycle in which an exhaust gas purifying device according to the present invention is incorporated. A first muffler 2 is connected to an exhaust port (not shown) of an engine 1. Is connected to the second muffler 3. The under cowl 4 is provided on the side of the engine 1.

As shown in FIG. 2, a pipe-shaped catalyst 5 is provided inside the first muffler 2. Pipe-shaped catalyst 5
Is a stainless steel perforated plate formed into a cylindrical shape. As shown in FIG. 3, the inner and outer peripheral surfaces and the periphery of each hole are coated with a noble metal catalyst 6. Returning to FIG. 2, the catalyst 5 is arranged so that its longitudinal direction is substantially along the axial direction of the first muffler 2 and at a predetermined distance from the inner wall of the first muffler 2. 8 are supported at two points.

FIGS. 4 and 5 show the support structure of the catalyst 5 by the stay 7 shown in the part A of FIG. 2. In order to support the catalyst 5 by the stay 7, the catalyst 5 is disposed on the outer peripheral surface of the catalyst 5. After the catalyst 5 is tightened by the clamp of the reinforcing plate 10 via the heat insulating material 9, the catalyst 5 is held via the reinforcing plate 10 by the bent portion 11 at the center of the stay 7, and both ends of the stay 7 are first It is fixed to the inner wall of the muffler 2. As the heat insulating material 9, ceramic fibers having heat insulating properties and cushioning properties, stainless steel mesh in which a stainless steel material is arranged in a mesh shape, or the like is used. FIGS. 6 and 7 show the support structure of the catalyst 5 by the stay 8 shown in the part B of FIG. 7. After the reinforcing plate 12 is fixed to the peripheral surface of the catalyst 5, the reinforcing plate 12 is welded to the stay. 8, and both ends of the stay 8 are fixed to the inner wall of the first muffler 2.

The support of the catalyst 5 by the stay 7 is a so-called floating support through the heat insulating material 9, while the support of the catalyst 5 by the stay 8 is a fixed support by welding. The location is set so as to be located on the engine exhaust port side 14 of the first muffler 2. The reason is that the exhaust gas at the engine outlet side has a high temperature and the reaction with the catalyst is more intense, so that it is necessary to make the reaction heat difficult to be transmitted to the first muffler 2. By doing so, the strength deterioration of the welded portion of the first muffler 2 due to the high temperature is more effectively prevented. In the above description, the catalyst 5 is supported at 2
Although the example in the case of the location has been described, the number of support locations is not limited thereto, and may be increased as appropriate. Also, the number of floating support points is not limited to one, and can be increased as appropriate. However, even in this case, the floating portion is located on the engine exhaust port side for the above-described reason.

Next, the operation will be described. Since the catalyst 5 is supported via the heat insulating material 9, the amount of heat transferred from the catalyst 5 to the first muffler 2 is small. Therefore, the temperature of the catalyst 5 rises quickly, and the time until the catalytic reaction starts in the cold state is relatively short. Further, the reaction heat of the catalyst 5 is hardly transmitted to the first muffler 2, so that it is not necessary to take measures against heat damage such as cowling. Further, since ceramic fiber or stainless steel mesh having cushioning properties is used as the heat insulating material 9, vibration of a vehicle or the like is hardly transmitted to the catalyst 5, and
Since the catalyst is also held so as to be thermally deformable, the thermal stress is reduced, and the durability of the catalyst 5 is improved. For this reason, the thickness of the pipe-shaped catalyst 5 can be reduced, so that cost and weight can be reduced.

Further, the exhaust gas on the engine exhaust side 14 has a high reaction temperature with the catalyst 5 due to the high temperature of the exhaust gas.
The reaction heat of the engine becomes higher, but this engine exhaust port side 1
4 is provided with a floating support position, so that the first muffler 2
High temperature heat of catalytic reaction is difficult to transmit.

[0015]

According to the present invention, since the catalyst is supported via the heat insulating material, the amount of heat transferred from the catalyst to the muffler is small, and the time required for the catalytic reaction to start is relatively short. Purification performance is improved. Further, the reaction heat of the catalyst is not easily transmitted to the muffler, so that it is not necessary to take measures against heat damage such as preventing the frame cover from being melted by heat and increasing the size of the muffler cover.

According to the present invention, the exhaust gas on the engine exhaust side is high in temperature and the reaction with the catalyst is more intense, and the reaction heat of the catalyst is high. However, a floating support position is provided on the engine exhaust side. Therefore, it is difficult for high-temperature catalytic reaction heat to be transmitted to the muffler.

[Brief description of the drawings]

FIG. 1 is a side view showing an entire motorcycle incorporating an exhaust gas purifying apparatus according to the present invention.

FIG. 2 is a partially cutaway sectional view showing an internal state of a first muffler.

FIG. 3 is a cross-sectional view showing a part of the catalyst.

4 is an enlarged view of a portion A of FIG. 1 and a cross-sectional view taken along line BB of FIG. 5;

FIG. 5 is a cross-sectional view along the line AA in FIG. 4;

6 is an enlarged view of a portion B in FIG. 1 and is a cross-sectional view along the line DD in FIG. 7;

FIG. 7 is a cross-sectional view along the line CC of FIG. 6;

FIG. 8 is a sectional view taken along a muffler axis of a conventional exhaust gas purification device.

9 is a sectional view along a plane orthogonal to the axis of FIG.

FIG. 10 is a sectional view taken along the muffler axis of another exhaust gas purifying device.

11 is a cross-sectional view along a plane orthogonal to the axis of FIG.

FIG. 12 is a cross-sectional view of another exhaust gas purifying device taken along a muffler axis.

FIG. 13 is a cross-sectional view along a plane orthogonal to the axis of FIG.

FIG. 14 is a sectional view taken along the muffler axis of another exhaust gas purifying device.

[Explanation of symbols]

 Reference Signs List 1 engine 2 first muffler 5 catalyst 9 heat insulating material 14 engine exhaust port side

Claims (1)

(57) [Claims] 1. An under cowl is provided on a side of an engine.
Is, first muffler is connected to an exhaust port of the engine, said first
Pie with precious metal catalyst coated inside muffler
The catalyst is provided in the form of a loop , and its longitudinal direction is the first mask.
From the inner wall of the first muffler approximately along the hula axis
Exhaust gas purification supported by stays at regular intervals
In the device, the exhaust gas purifying device may include a disconnection device disposed on an outer peripheral surface of the catalyst.
Heat material is clamped by the clamp of the reinforcing plate,
A floating support point that holds the catalyst in the bent part of the stay ,
After fixing the reinforcing plate on the peripheral surface of the catalyst, the reinforcing plate is
And a fixed support portion welded to the bent portion of the first muffler, and the floating support portion is connected to the engine exhaust port side of the first muffler.
An exhaust gas purifying apparatus characterized in that the exhaust gas purifying apparatus is set at a position .