JPH08105314A - Apparatus for filtering exhaust fine grain of internal combustion engine - Google Patents

Abstract

PURPOSE: To enable gauze deformed radially outward as a whole to hold the condition in close contact with a filter tube without deforming complicatedly the gauze according to the thermal expansion. CONSTITUTION: A filter tube 10 is formed by tubularly winding nets 13, 15 superposed on both surfaces of a non-woven fabric consisting of ceramic fibers. The nets 13, 15 are woven by warp and weft which are inclined relative to the axis of the filter tube 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust particulate filter for a diesel engine in which a wire mesh is superposed on both sides of a nonwoven fabric made of ceramic long fibers or the like and wound in a tubular shape.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional exhaust particulate filter has a cylindrical case 45 which is conical with a partition plate 43 having a large number of through holes 43a in the peripheral portion at equal intervals in the circumferential direction at the left end thereof. While connecting the tube 42 and connecting the inlet pipe 41 to the conical tube 42, the end plate 47 is connected to the right end of the case 45.
An outlet pipe 49 is connected to a through hole 48 provided at the center of 7.
The filtration cylinder 10 disposed inside the case 45 has a wire mesh 1 made of stainless wire or the like on both inner and outer surfaces of a nonwoven fabric 14 formed by laminating ceramic fibers or the like and irregularly intertwined with each other.
3 and 15 are superposed on each other and wound in a tubular shape, and both end portions are joined by sandwiching the heat shield plates 44 and 46 between the partition plate 43 and the end plate 47.

When exhaust particles such as carbon are collected in the filter cylinder 10, the metal nets 13 and 15 are energized to burn the exhaust particles to regenerate the filter cylinder 10. The heat shield plate 4 is provided between the case 45 and the filter cylinder 10 in order to suppress the heat dissipation from the filter cylinder 10 and to minimize the electric power supplied to the wire nets 13 and 15.
4,46 are sandwiched. Therefore, even when the temperature of the filter cylinder 10 is 900 ° C, the temperature of the case 45 is about 200 ° C, and when the total length of the case is 500 mm, the axial direction generated between the case 45 and the filter cylinder 10 due to thermal expansion. The difference in elongation reaches about 5-8 mm.

As shown in FIG. 8, in the conventional filter cylinder 10, the vertical lines 13a and the horizontal lines 13b of the wire nets 13 and 15 are the filter cylinder 10.
Since they are arranged in the axial direction and the circumferential direction of the wire mesh 13,1
If the axial extension of 5 is larger than that of the case 45,
The vertical line 13a is prevented from freely extending in the axial direction, the wire nets 13 and 15 are complicatedly curved as shown in FIG. 9, and the nonwoven fabric 1 made of ceramic fibers sandwiched between the wire nets 13 and 15 is formed.
Since No. 4 does not deform in the same manner as the metal nets 13 and 15, the metal nets 13 and 15 are partially peeled from the nonwoven fabric 14 and cannot be restored to the original shape. Wire mesh 1 as described above
In the deformed state of 3, 15, heat is not effectively transferred to the non-woven fabric 14 even when the wire nets 13, 15 are energized, the temperature distribution of the non-woven fabric 14 becomes non-uniform, and exhaust particulates such as carbon trapped in the non-woven fabric 14 are obtained. Can not be burned efficiently,
Exhaust particulates remain unburned.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to deform the wire mesh radially outward as a whole without causing complicated deformation due to thermal expansion, and bring the filter cylinder and the wire mesh into close contact with each other. It is an object of the present invention to provide an exhaust particulate filter device for a diesel engine, which is kept in such a state.

[0006]

In order to achieve the above-mentioned object, the structure of the present invention is an exhaust gas of a diesel engine having a filter cylinder in which a mesh is superposed on both sides of a nonwoven fabric made of ceramic fiber and is wound in a cylindrical shape. In the fine particle filtration device, the vertical and horizontal lines of the mesh are inclined with respect to the central axis of the filter cylinder.

[0007]

The filter cylinder is constructed by winding a non-woven fabric on both sides of which a wire mesh is superposed and wound into a cylindrical shape. The vertical and horizontal lines of the wire mesh are not aligned in the axial direction of the filter cylinder, but are preferably inclined at 45 ° with respect to the central axis of the filter cylinder and arranged in a spiral shape.

When the vertical and horizontal lines of the wire mesh are stretched during energization, the tubular filter tube swells as a whole. That is, the inner diameter of the filter cylinder widens and does not extend in the axial direction. As a result, the wire mesh is not partially deformed in a complicated manner and does not peel off from the nonwoven fabric or return to its original shape.

Since the wire mesh is always in close contact with the nonwoven fabric, the heat of the wire mesh is efficiently transferred to the nonwoven fabric when energized, and the exhaust particulates collected in the nonwoven fabric are burned out.

[0010]

1 is a side sectional view of an exhaust particulate filter of a diesel engine in which a filter cylinder according to the present invention is adopted.
The exhaust particulate filter has a conical cylinder 2 at the left end of a cylindrical case 4.
Is connected by a bolt 3, an end plate 6 is connected by a bolt 5 to the right end of the case 4, and a filter cylinder 10 is arranged inside the case 4. The inlet 2a of the conical cylinder 2 is connected to the exhaust manifold of the engine via the exhaust pipe, and the outlet 6a of the end plate 6 is connected to the silencer via the exhaust pipe.

The filtration cylinder 10 uses a non-woven fabric 14 in which ceramic long fibers are laminated in an irregular direction and partially entangled with each other, and a metal mesh 13 such as stainless steel is provided on the outer surface of the non-woven fabric 14.
The inner surface is formed by stacking similar wire nets 15 in a cylindrical shape. The filter cylinder 10 has inner cylinders 12 and 17 each having an L-shaped cross section fitted on the inner surfaces of both ends thereof, and has a clamp ring 8 on the outer surface.
16 is wound and combined. The inner cylinder 12 is connected to the cover plate 7 by bolts 9. The inner cylinder 17 is joined to the end plate 6 with the heat shield ring 18 interposed therebetween.

Exhaust gas flows from the inlet 2a between the inner surface of the case 4 and the outer surface of the filter cylinder 10 and passes through the filter cylinder 10 to the inside of the filter cylinder 10 while the exhaust particulates are separated by the nonwoven fabric 14. . The cleaned exhaust gas flows from the inside of the filter cylinder 10 to the outlet 6a.

As shown in FIG. 2, the filter cylinder 10 uses a felt or non-woven fabric 14 in which fibers such as ceramics are aligned and laminated, and the fibers are irregularly entangled in a direction perpendicular to the laminated surface. Preferably, the non-woven fabric 14A having coarse mesh is provided on the exhaust inlet side, and the non-woven fabric 14 having fine mesh is provided on the exhaust outlet side.
B is overlaid on both sides of the non-woven fabric 14 and the wire mesh 13,
Stack 15 and stick them together.

As shown in FIG. 3, according to the present invention, the wire mesh 13 superposed on the non-woven fabric 14 has vertical lines 13a and horizontal lines 1
3b are not aligned in the central axis line x direction of the tubular filter cylinder 10, but are arranged so as to intersect at an inclination angle of about 45 °. That is, vertical line 1
3a and the horizontal line 13b are arranged in a spiral shape on the filter cylinder 10. The wire net 15 has the same structure.

When the wire nets 13 and 15 are heated to a high temperature during energization and the vertical lines 13a and the horizontal lines 13b are stretched, as shown in FIG.
The intersection angle θ between the vertical line 13a and the horizontal line 13b of the wire nets 13 and 15 becomes small, and the filter cylinder 10 as a whole expands or has a large diameter, but does not extend in the axial direction of the filter cylinder 10. Therefore, the wire nets 13 and 15 are not separated from the non-woven fabric 14 or deformed in a complicated manner, and are restored to their original shape when the power supply is stopped. Since the metal nets 13 and 15 are always in close contact with the non-woven fabric 14, when the metal nets 13 and 15 generate heat by energization, the heat is efficiently transferred from the metal nets 13 and 15 to the non-woven fabric 14 to remove the exhaust particulates trapped in the non-woven fabric 14. Burn out.

In the embodiment shown in FIG. 5, instead of diagonally arranging all the vertical lines 13a and the horizontal lines 13b of the wire net 13, the vertical lines 13a and the horizontal lines 13b are axially and circumferentially arranged in the central portion of the filter cylinder 10. Arranged, but the wire mesh 13A at both ends is warp 1
3a and the weft 13b are arranged obliquely with respect to the central axis line x. When energized, the wire mesh 13 extends in the axial direction at the center of the filter cylinder 10, but the wire mesh 13 extends at both ends.
Absorbed by A. That is, the wire mesh 13A is the vertical line 13
Since a and the horizontal line 13b are obliquely arranged, the filter cylinder 10 as a whole expands radially outward and absorbs the extension in the central axis x direction. The wire net 15 has the same structure.

As shown in FIG. 6, even if the wire nets 13 and 15 are woven into a honeycomb shape, axial elongation can be absorbed.

[0018]

Industrial Applicability As described above, the present invention provides an exhaust particulate filter for a diesel engine having a filter cylinder in which a mesh is laminated on both surfaces of a nonwoven fabric made of ceramic fiber and wound in a cylindrical shape. Since the line and the horizontal line are inclined with respect to the central axis of the filter cylinder, when the vertical line and the horizontal line of the wire mesh are stretched during energization, the filter cylinder only swells as a whole, and the axial extension of the filter cylinder is increased. It can be suppressed. This solves the problem that the wire mesh partly deforms in a complicated manner and peels off from the non-woven fabric or does not return to its original shape.

Since the metal net is always in close contact with the non-woven fabric, the heat of the metal net is efficiently transferred to the non-woven fabric when energized, and the exhaust fine particles collected in the non-woven fabric are uniformly burned off.

[Brief description of drawings]

FIG. 1 is a side sectional view of an exhaust particulate filter for a diesel engine according to the present invention.

FIG. 2 is a side sectional view showing a main part of a filter cylinder of the exhaust particulate filter device.

FIG. 3 is a side view showing the lower half of the wire netting of the filter cylinder with the lower half omitted.

FIG. 4 is a side view showing a state during heating of the wire net.

FIG. 5 is a side view showing a wire mesh of a filter cylinder according to a modified embodiment of the present invention.

FIG. 6 is a side view showing a main part of a wire mesh of a filter cylinder according to a modified embodiment of the present invention.

FIG. 7 is a side sectional view of a conventional exhaust particle filtering device for a diesel engine.

FIG. 8 is a side view showing a wire mesh of a filter cylinder of the exhaust particulate filter.

FIG. 9 is a side view showing a modification of the wire net of the filter cylinder.

[Explanation of symbols]

2: conical cylinder 2a: inlet 4: case 6: end plate 6
a: outlet 7: end plate 8, 16: tightening ring 10: filtration cylinder 12, 17: inner cylinder 13, 13A, 15: wire mesh 13
a: Vertical line 13b: Horizontal line 14, 14A, 14B: Nonwoven fabric 18: Heat shield ring

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B01D 46/00 302

Claims (5)

[Claims] 1. In an exhaust particulate filter of a diesel engine having a filter cylinder in which a mesh is laminated on both sides of a nonwoven fabric made of ceramic fiber and wound in a cylindrical shape, the vertical and horizontal lines of the mesh are the centers of the filter cylinder. An exhaust particulate filter for a diesel engine, which is inclined with respect to the axis. 2. The exhaust particulate filter of a diesel engine according to claim 1, wherein the vertical and horizontal lines of the mesh are inclined at 45 ° with respect to the central axis of the filter cylinder. 3. The exhaust particulate filter of a diesel engine according to claim 1, wherein the mesh is woven in a honeycomb shape. 4. The exhaust particulate filter for a diesel engine according to claim 1, wherein the mesh is made of a conductive material, and the exhaust particulate collected in the filter cylinder is burned by energizing the mesh. 5. An exhaust particulate filter for a diesel engine having a filter cylinder in which a mesh is laminated on both sides of a non-woven fabric made of ceramic fiber, and the filter is a longitudinal part of the mesh in a part of the filter cylinder in the front-rear direction. The line and the horizontal line are arranged to be inclined with respect to the central axis of the filter cylinder, and in other parts, the vertical line and the horizontal line of the mesh are arranged parallel to the central axis of the filter cylinder. Fine particle filter.