JP3161672B2 - Exhaust particulate filter - 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 particulate filtering apparatus for removing exhaust particulates (particular) such as carbon from exhaust gas of a diesel engine.

[0002]

2. Description of the Related Art An exhaust particulate filter for collecting exhaust particulates such as carbon in exhaust gas of a diesel engine employs a porous honeycomb formed body made of ceramic and a foamed porous body made of ceramic. And those using a nonwoven fabric made of inorganic fibers are known. As a method of regenerating the exhaust particulate filter, there are a method of igniting and burning the collected exhaust particles with a flame of a burner, a method of utilizing combustion propagation, and a method of igniting and burning by electric heat.

[0003] In a filter using a ceramic molded body, when exhaust fine particles are collected on the surface, pores of the filter become smaller and the pressure loss due to fluid resistance increases rapidly. During regeneration by combustion of exhaust particulates, the combustion temperature is 140
It may reach 0 ° C., and the filter may be damaged or melted. On the other hand, a filter using inorganic fibers burns exhaust fine particles, so that it is difficult to quickly and uniformly heat the filter.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an exhaust particulate filtering apparatus in which a filter is quickly and uniformly heated to efficiently burn exhaust particulates.

[0005]

Means for Solving the Problems In order to achieve the above-mentioned object, the construction of the present invention is such that a net-like body is superposed on both sides of a laminate obtained by laminating ceramic fibers and entangled irregularly, and a cylindrical shape is formed. In the exhaust particulate filtration device having a filter body curved to form a mesh, the mesh is formed of a non-conductive material, and a mesh for conduction heating made of a conductive material is sandwiched inside the laminate. And

[0006]

The filtering body (filter) is formed by laminating ceramic fibers and arranging them irregularly and wrapping a net-like body on both sides, and then bending the filter into a cylindrical shape. Exhaust fine particles are collected while the exhaust gas passes from the outer periphery of the filter to the inner space of the filter, or passes from the inner space of the filter to the outer periphery of the filter. Exhaust particulates are concentrated and deposited on the exhaust outlet surface or the back surface of the filter.

[0007] A current is applied to the mesh member in contact with the back surface of the filter, and fresh pressurized air or a part of the exhaust gas is caused to flow through the filter to burn exhaust particulates, thereby regenerating the filter.

[0008]

FIG. 1 is a side sectional view of an exhaust particulate filter according to the present invention, and FIG. 2 is a side sectional view of a filter of the exhaust particulate filter. Exhaust particulate filter is a cylindrical case 5
4 accommodates a cylindrical filter body A, and a case 5
The center opening of the fourth end plate 53 is connected to the inlet pipe 51. On the other hand, the center opening of the end plate 55 is connected to the outlet pipe 58. In order to supply fresh air to the filter body A, an air supply pipe 59 a extending from a high-pressure air tank or a blower 59 is projected to the inlet pipe 51.

The filter body A is formed in a cylindrical shape by laminating nets 61 and 63 on both sides of a laminate 62 such as a nonwoven fabric or felt made of ceramic fibers laminated and entangled irregularly. The left end of the filter A is closed by a circular end plate 60. On the other hand, the right end of the filter A is an annular end plate 6.
4 are combined. The outer peripheral edge of the end plate 64 is connected to the inner peripheral wall of the case 54.

The nets 61 and 63 are made of a non-conductive material. The nets 61 and 63 are woven fabrics made of ceramic fibers such as SiC (silicon carbide) and alumina.

As shown in FIG. 2, the nets 61 and 63 superposed on both sides of the laminate 62 are held together by a heat-resistant wire 67 penetrating the laminate 62. As the heat-resistant wire rod 67, a conductive metal wire such as stainless steel or a non-conductive thread such as ceramic fiber is used. Reticulated bodies 61, 6 superimposed on both front and back sides of laminate 62
3 are mutually trapped by the metal wires 67 penetrating the laminate 62, the heat of the meshes 61, 63 can be quickly transmitted to the laminate 62, and the reburning of the exhaust fine particles can be promoted, and the regeneration time can be reduced. . As shown in FIG. 2, a ring 69 is inserted into both ends of the laminate 62, while a metal band 68
And the electrode 73 (FIG. 1) is connected to the mesh body 63.

[0012] As shown in FIG.
The reticulated bodies 61 and 63 superposed on both surfaces are made of a non-conductive material, and a reticulated body 65 made of a conductive material is sandwiched inside the laminated body 62. By sandwiching the mesh 65 made of a conductive material inside the laminate 62, the filter A
During regeneration, heat dissipation can be suppressed, and the laminate 62 can be quickly and uniformly heated. In the illustrated embodiment, the mesh body 65 is a metal mesh made of a heat-resistant metal such as stainless steel or an Fe-Cr-Al (iron-chromium-aluminum) alloy, and both ends of the mesh body 65 are connected to electrodes. .

The exhaust gas from the engine is supplied from the inlet pipe 51 to the filter A
Supplied to That is, while the exhaust gas passes through the stacked body 62 radially inward from the outer peripheral space 71 of the filter body A, the exhaust fine particles contained in the exhaust gas are collected. The exhaust gas from which the exhaust particles have been removed flows out from the inner space 72 to the outlet pipe 58.

To regenerate the filter A, the electrodes at both ends of the mesh 65 are connected to a power source (not shown), and the mesh 65 is energized. The exhaust to the filter A is bypassed, and the blower 59
Is driven, the exhaust fine particles are burned while fresh air from the air supply pipe 59a passes through the laminated body 62 from the outer peripheral space 71 to the inside in the radial direction. The air from which the exhaust particulate has been burned flows from the inner space 72 of the filter A to the outlet pipe 58.

In the embodiment shown in FIG. 4, the filter body A is not a simple cylindrical one, but the filter body A is alternately meandering inwardly and outwardly in a star or cross section. Things,
The area through which the exhaust gas passes can be increased, and the filtration capacity can be increased. The filter body A is curved in a cylindrical shape after being formed into a waveform by a jig in advance, and a plurality of portions at both end portions and an intermediate portion in the axial direction,
For example, it is sandwiched between an inner holding plate 37 and an outer holding plate 35 having an appropriate thickness formed of ceramic or the like. The inner holding plate 37 is engaged with a large number of protruding pieces 37b projecting radially outward from the annular portion 37a into grooves on the inner peripheral side of the filter body A. The outer holding plate 35 is engaged with a number of protrusions 35 b projecting radially inward from the annular portion 35 a into grooves on the outer peripheral side of the filter A. Preferably, the outer holding plate 35 is divided in the circumferential direction and is captured by the metal band 34.

[0016]

As described above, according to the present invention, a filter body is formed by laminating a net-like body on both sides of a laminate obtained by laminating ceramic fibers and entangled irregularly, and then bending it into a cylindrical shape. In the exhaust particulate filtration device, the mesh is made of a non-conductive material, and the mesh for electric heating made of a conductive material is sandwiched inside the laminate, so that the following effects are obtained. .

The amount of heat dissipated is suppressed, the laminate is quickly and uniformly heated by energizing the heating and heating mesh sandwiched inside the laminate on which the exhaust particulates are deposited, and the collected exhaust particulates are collected. Can be reburned to regenerate the filter.

The reticulated bodies superimposed on both sides of the laminated body are mutually trapped by a heat-resistant wire penetrating the laminated body, whereby the heat of the reticulated body is quickly transmitted to the laminated body, and the exhaust particulates are reburned. And shorten the playback time.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an exhaust particulate filtration device according to the present invention.

FIG. 2 is a side sectional view of a filter of the exhaust particulate filter.

FIG. 3 is a side sectional view of a filter of an exhaust particulate filter according to a modified embodiment of the present invention.

FIG. 4 is a front sectional view of a filter of an exhaust particulate filter according to a modified embodiment of the present invention.

[Explanation of symbols]

A: Filter body 35: Outside holding plate 35a: Annular part 35
b: protruding piece 37: inner holding plate 37a: annular portion 37
b: Projecting piece 51: Inlet pipe 54: Case 58: Outlet pipe 59: Blower 59a: Air supply pipe 61, 63: Net-like body 72: Inner space 73, 74: Electrode

Claims (2)

(57) [Claims] 1. An exhaust particulate filtration apparatus comprising a filter body formed by laminating a ceramic fiber on both sides of a laminate formed by laminating ceramic fibers and entangled irregularly, and forming a filter body by bending the filter body into a cylindrical shape. An exhaust particulate filtering device, characterized in that the body is made of a non-conductive material, and a mesh for conduction heating made of a conductive material is sandwiched inside the laminate. 2. The exhaust particulate filtering apparatus according to claim 1, wherein the nets superposed on both sides of the laminate are mutually bound by a heat-resistant wire penetrating the laminate.