JP3472534B2 - 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 emission control device.

[0002]

2. Description of the Related Art Particulate Matter emitted from a diesel engine:
Particulate matter includes soot composed of carbonaceous matter and SOF component (Soluble Organic) composed of high boiling point hydrocarbon components.
Fraction: Soluble organic component)
Further, the composition is such that it contains a slight amount of sulfate (mist-like sulfuric acid component). As a measure for reducing this type of particulates, as shown in FIG. 5, an exhaust pipe through which exhaust gas 2 from a diesel engine 1 flows. It is considered to equip the particulate filter 4 in the middle of 3.

As shown in FIG. 6, the particulate filter 4 has a porous honeycomb structure made of a ceramic such as cordierite, and the inlets of the channels 5 partitioned in a grid pattern are alternately plugged. As for the flow path 5 whose inlet is not plugged, its outlet is plugged, and only the exhaust gas 2 that has permeated through the porous thin wall 6 partitioning each flow path 5 is on the downstream side. The particulates are discharged onto the inner surface of the porous thin wall 6 to collect the particulates.

[0004]

However, in the conventional particulate filter 4 as described above, there is a problem that the manufacturing cost thereof is high because the particulate filter 4 has to be manufactured as an integrally molded product having a complicated honeycomb structure.
In addition, when the particulate filters 4 having different capacities are required depending on the vehicle type and the like, there is a problem that a plurality of types of particulate filters 4 having different capacities must be individually manufactured at high manufacturing cost. It was

The present invention has been made in view of the above situation, and an object of the present invention is to provide an exhaust emission control device capable of significantly reducing the manufacturing cost and easily adjusting the capacity as compared with the prior art.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, a flat plate filter having a porous structure having a coarse mesh for deep-filtration of particulates is provided in a filter case interposed in the middle of an exhaust pipe in the exhaust gas flow direction. to accommodate superimposed multiple sheets
At the same time, each flat plate filter is installed in the filter case.
Moves in the flow direction of the nozzle and in a direction substantially perpendicular to the flow direction
Do not press it with an elastic cushion material to prevent it from
Also, each flat plate filter may be attached to an exhaust gas
When pressurizing and holding in the flow direction of the filter,
At the front and back of each plate filter.
Also, it is divided into front and back at either position,
Filter set to the adjacent set of filter cases.
Attach the caps to each of the divided filter cases.
When reattaching each, between the two filter stoppers
Each flat plate filter is pressed through the elastic cushion material.
The present invention relates to an exhaust emission control device having the above-mentioned configuration .

Therefore, according to the present invention, since a plurality of flat plate filters, which are simply manufactured into a simple plate shape, are stacked in the exhaust gas flow direction and used as a filter layer, a complicated honeycomb structure as in the conventional case is used. It becomes possible to keep the manufacturing cost low compared to the case where the particulate filter having the structure is manufactured as an integrally molded product,
Moreover, it is possible to adjust the capacity extremely simply by adjusting the number of flat plate filters.

Further, since each flat plate filter has a porous structure with coarse mesh so that the particulates can be deep-layer filtered, when exhaust gas passes through each flat plate filter,
Particulate particles will repeatedly collide with the column portion that forms pores in each flat plate filter repeatedly and be collected in one of the column portions. Even if it can pass through the flat plate filter of the above, it will be collected in a relatively deep layer portion of one of the flat plate filters while passing through each flat plate filter in the latter half. It is possible to suppress exhaust resistance to a small level while maintaining a high collection capacity that is not inferior to the above, and moreover, by efficiently utilizing the volume of each flat plate filter to prevent clogging in a short period of time. It is possible to prevent it.

[0009] Further, each flat filter is held under pressure by substantially elastic cushion material so as not to move in the perpendicular direction to the flow direction and flow Re direction of the exhaust gas in the filter casing, in particular exhaust each flat filter In the direction of gas flow
When holding under pressure, the husband of the divided filter case
Each flat plate between both filter stoppers
The filter is pressed so that it can be pressed well in the exhaust gas flow direction.
Since each flat plate filter is held, it becomes possible to firmly hold each flat plate filter so that it does not rattle due to passage of exhaust gas even if the thickness of each flat plate filter is reduced. It is possible to suppress the wear of the flat plate filter and reduce the thickness of each flat plate filter.

Further, since the filter case is divided into front and rear portions at at least one of the front and rear positions sandwiching each flat plate filter , the filter case is divided into front and rear portions at the division position to separate each flat plate filter. It is possible to take out all or part of the product from the inside and easily perform cleaning or replacement.

Here, in particular, when the filter case is divided into both front and rear positions sandwiching each flat plate filter,
It is possible to remove the flat plate filter together with the divided pieces of the filter case and replace the cassette while keeping the flat plate filter in the housed state.

Further, it is preferable that each flat plate filter carry an oxidation catalyst. By doing so, the oxidation reaction of the particulates trapped by each flat plate filter is promoted by the oxidation catalyst, which results in comparison. The particulates are efficiently burned and removed at an extremely low ignition temperature.

In the present invention, for example, the filter case may be an outer cylinder of the muffler, and the plate filters may be housed in the muffler.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an example of an embodiment for carrying out the present invention. As shown in FIG. 1, in the exhaust gas purification apparatus of this embodiment, the exhaust gas is discharged from a diesel engine 1 of an automobile (see FIG. 5). Exhaust pipe 3 through which the generated exhaust gas 2 flows
The case where the outer cylinder of the muffler 7 is a filter case 8 is illustrated.

That is, a storage space 14 of a required size defined by the first separator 12 and the second separator 13 is secured between the inlet pipe 9 of the muffler 7, the outlet pipe 10 and the inner pipe 11. , This accommodation space 1
In FIG. 4, a plurality of flat plate filters 15 (see FIG. 2) each having a porous structure with coarse mesh so as to enable deep filtration of particulates and formed in a disc shape are overlapped in the flow direction of the exhaust gas 2. Are to be accommodated.

Here, each flat plate filter 15 is made of a foam metal, a foam ceramic, a compressed body of a metal wire, a compressed body of a metal fiber or an inorganic fiber, and the like, and is finer than a conventional ceramic particulate filter. The hole sizes are significantly different.

That is, while the conventional particulate filter was intended for surface layer filtration, the eyes were made fine so that the pores had a diameter smaller than the particle diameter of the particulate.
In each flat plate filter 15 shown here, the particles of the particulates are repeatedly collided with the pillar part forming the pores of each flat plate filter 15 repeatedly to be collected in one of the pillar parts. Intended for deep layer filtration, the diameter of the pores is made larger than the particle diameter of the particulates, and more specifically, about 0.7 mm to 2.0 mm.
It is designed to form pores having a diameter of a certain degree.

Further, each flat plate filter 15 carries an oxidation catalyst such as platinum-alumina so as to promote the oxidation reaction of the collected particulates.

As shown in an enlarged view of the cross section of the upper portion in FIG. 3, annular spacers 16 are interposed between the flat plate filters 15 so that the flat plate filters 15 do not come into direct contact with each other. A cylindrical spacer 18 is encapsulated on the outer peripheral surface of the filter layer 17 formed by each flat plate filter 15, and between the spacer 18 and the canning outer cylinder 19 fixed to the inner peripheral surface of the filter case 8. The elastic cushion members 20 and 21 are interposed, and the seal member 22 is interposed between the elastic cushion members 20 and 21 to prevent the bypass of the exhaust gas 2.

Here, each elastic cushion material 20, 21
Is a metal wire knitted into a bellows cylindrical shape, and suppresses the radial movement of each flat plate filter 15 (movement in a direction substantially perpendicular to the flow direction of the exhaust gas 2). In order to obtain it, the outer peripheral portion of each plate filter 15 is pressed and held by elastic force.

Further, the front end portion 20a of the front elastic cushion member 20 is reduced in diameter so as to wrap around the front side outer edge portion of the plate filter 15 in the front row, and immediately after the rear elastic cushion member 21, Last row flat plate filter 1
5, an annular seal material 22 is arranged so as to be hung also on the rear side outer edge portion of the filter layer 17, and the front end portion 20a of the front elastic cushion material 20 and the seal material 22 are interposed in the front-rear direction. Is the filter stopper 23,
It is adapted to be pressed back and forth by 24, and the flat filter 15 is pressurized and held by the elastic force of the front end portion 20a of the front elastic cushion member 20 so as not to move in the flow direction of the exhaust gas 2.

That is, in the present embodiment, the filter case 8 is divided into the front and the rear at a position rearward of the flat plate filter 15 in the last row, and the front filter stopper 23 described above with respect to the front filter case 8. It is mounted via the canning outer cylinder 19 and has a filter stopper 24 at the rear.
However, since it is attached to the rear filter case 8, the rear filter case 8 is removed and each flat plate filter 15 is housed in the front filter case 8 and then the rear filter case 8 is inserted. When the case 8 is attached again, the flat plate filters 15 are pushed forward by the rear filter stoppers 24, so that both filter stoppers 23, 2
It is designed to be crushed between four.

A flange 25 is formed at each of the divided connection-side end portions of the filter case 8, and the front and rear filter cases 8 are connected by bolting the flanges 25 together via a gasket 26. Is done.

In the exhaust gas purification device thus constructed, a plurality of flat plate filters 15 which need only be manufactured in a simple plate shape are stacked in the flow direction of the exhaust gas 2 and used as the filter layer 17. I am doing so
The manufacturing cost can be kept low as compared with the conventional case where a particulate filter having a complicated honeycomb structure is manufactured as an integrally molded product, and the capacity can be extremely easily reduced by adjusting the number of the flat plate filters 15. Can be adjusted.

Since each flat plate filter 15 has a porous structure with coarse mesh so that the particulates can be deep-layer filtered, when the exhaust gas 2 passes through each flat plate filter 15, particulates of the particulates are Each of the flat plate filters 15 repeatedly collides with a column part forming pores and is repeatedly collected by any one of the column parts. Even if it can pass, it will be trapped in a relatively deep layer portion of one of the flat plate filters 15 while passing through each flat plate filter 15 in the latter half, and thus is inferior to the conventional particulate filter having a honeycomb structure. It is possible to suppress the exhaust resistance to a small level while maintaining a high collection capacity, and moreover, the volume of each flat plate filter 15 is efficiently used for collection in a short period of time. Possible to prevent the occurrence of clogging in the it is possible.

Further, particularly in this embodiment, the elastic cushion members 20 and 21 prevent the flat plate filters 15 from moving in the filter case 8 in the flow direction of the exhaust gas 2 and in a direction substantially perpendicular to the flow direction. Since the pressure is maintained, even if the thickness of each flat plate filter 15 is reduced,
It becomes possible to firmly hold each flat plate filter 15 so as not to cause rattling due to passage of the exhaust gas 2.
It is possible to suppress the wear of each flat plate filter 15 and reduce the thickness dimension of each flat plate filter 15.

That is, since the conventional particulate filter having a honeycomb structure is an integrally molded product,
Although it was sufficient to press and hold only the outer peripheral portion with a cushion material, such a conventional holding method is used in the filter layer 1 including a plurality of flat plate filters 15 as in this embodiment.
Even if it is applied to No. 7 as it is, the individual thickness dimensions of the flat plate filter 15 are too small, and it becomes difficult to pressurize and hold the flat plate filter 15 from the outer peripheral side satisfactorily. since there is a concern that it becomes likely to occur per, each flat filter 15 both filters strike
By sandwiching between the lids 23 and 24, the exhaust gas 2 is also pressurized and held in the flow direction to increase the holding force, and the flat plate filter 15
Each flat plate filter 1 without depending on the individual thickness of
5 can be firmly held under pressure.

Further, in particular, in this embodiment, the filter case 8 is divided into the front and the rear at the position rearward of the flat plate filter 15 in the last row, and therefore the rear filter case 8 is removed at the divided position. All or part of each flat plate filter 15 can be taken out from the inside of the filter case 8 on the front side for easy cleaning and replacement.

In the example shown here, the filter case 8 is divided into the front and rear portions at the position rearward of the flat plate filter 15 in the last row, but, for example, as shown in FIG. The filter case 8 is attached to each flat plate filter 15
It is also possible to make a split configuration at both front and rear positions with the filter sandwiched between them. In such a case, the cassettes can be exchanged by removing the flat plate filters 15 together with the split pieces of the filter case 8 while keeping each flat plate filter 15 in the accommodated state. Is possible.

Further, in the present embodiment, since each flat plate filter 15 carries an oxidation catalyst, the oxidation reaction of the particulates trapped by each flat plate filter 15 is promoted by the oxidation catalyst, which results in comparison. Since the particulates are efficiently burned and removed at an extremely low ignition temperature, each flat plate filter 15 can be continuously used for a long period of time.

The exhaust gas purifying apparatus of the present invention is not limited to the above-described embodiment, but the filter case may be provided separately from the muffler, and other points deviate from the gist of the present invention. It goes without saying that various changes can be made within the range not covered.

[0033]

According to the exhaust gas purification apparatus of the present invention described above, various excellent effects as described below can be obtained.

(I) The manufacturing cost can be kept low as compared with the conventional case where a particulate filter having a complicated honeycomb structure is manufactured as an integrally molded product, and moreover, the number of flat plate filters is simply adjusted. Since the capacity can be adjusted very easily, it is possible to eliminate the waste of individually manufacturing multiple types of particulate filters with different capacities according to the vehicle type, etc. at a high manufacturing cost, and to make each plate filter a common component. By doing so, the overall cost can be reduced reasonably.

(II) Since a plurality of flat plate filters having a porous structure with a coarse mesh so that the particulates can be deep-layer filtered are stacked to form a filter layer, a high collection rate comparable to that of a conventional particulate filter having a honeycomb structure is obtained. The exhaust resistance can be suppressed to be small while maintaining the capacity, and the clogging can be prevented in a short period of time by efficiently utilizing the volume of each flat plate filter for collection.

[0036] (III) each flat filter are dwell by the elastic cushion material so as not to move in a substantially perpendicular orientation to the flow direction and flow Re direction of the exhaust gas in the filter casing, in particular exhaust each flat filter How gas flows
Separated filter case to hold pressure
When reattaching each of the
The flat plate filter is pressed to improve the exhaust gas flow direction.
Since it is held under pressure, even if the thickness of each flat plate filter is reduced, each flat plate filter can be firmly held to prevent rattling due to passage of exhaust gas. It is possible to suppress the wear of the filters and reduce the thickness of each flat plate filter.

[0037] (IV) is off Irutakesu can easily be cleaned or replaced is taken out from the inside of the whole or part of each flat filter to separate the front-rear split position, in particular the flat filters filter case When the flat filter is divided into both the front and rear positions, the flat plate filters can be removed together with the divided pieces of the filter case and the cassette can be exchanged while the flat plate filters are kept in the accommodated state.

(V) If each plate filter has an oxidation catalyst supported thereon, the oxidation reaction of the particulates trapped by each plate filter is promoted by the oxidation catalyst, and at a relatively low ignition temperature. Since the particulates can be efficiently burned and removed, each flat plate filter can be continuously used for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an embodiment for carrying out the present invention.

FIG. 2 is a perspective view of each flat plate filter of FIG.

FIG. 3 is an enlarged sectional view showing a holding structure for each flat plate filter shown in FIG.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a schematic view showing a conventional example.

FIG. 6 is a cross-sectional view showing details of the particulate filter of FIG.

[Explanation of symbols]

2 exhaust gas 3 exhaust pipe 7 mufflers 8 filter cases 15 flat plate filter 20 elastic cushion material 21 Elastic cushion material

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F01N 3/28 311 F01N 3/28 311U B01D 53/36 103C (72) Inventor Toshiki Oya 3-chome Hinodai, Hino-shi, Tokyo 1 Hino Motors, Ltd. (56) Reference JP 4-255513 (JP, A) JP 60-204913 (JP, A) JP 11-350952 (JP, A) JP 7- 286510 (JP, A) JP 2000-130150 (JP, A) Actual Kaihei 2-31328 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F01N 3/02 B01D 46 / 10 B01D 53/94 F01N 3/28

Claims (3)

(57) [Claims] 1. A plurality of flat plate filters having a porous structure with coarse mesh for deep-layer filtration of particulates are accommodated in a filter case interposed in the middle of an exhaust pipe in the exhaust gas flow direction. Together with the plate filters
The flow direction of exhaust gas in the filter case and the flow direction
Elastic cushion to prevent movement in a direction substantially perpendicular to the direction
The plate is held under pressure, and each plate filter is
The cushioning material keeps pressure in the exhaust gas flow direction.
The flat plate filter between the filter cases.
Back and forth in at least one position
Of the divided filter cases
Attach the filter stoppers to each adjacent set,
When reattaching each of the divided filter cases
Each plate filter is elastically clamped between the two filter stoppers.
An exhaust emission control device characterized in that it is configured so as to be pressed through an optional material . 2. The exhaust emission control device according to claim 1 , wherein an oxidation catalyst is carried on each flat plate filter. 3. The exhaust emission control device according to claim 1 or 2 , wherein the filter case forms an outer cylinder of the muffler.