JP2002276336A - Diesel exhaust gas particulate removing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further render hazardous material harmless, realize improvement in soot removing efficiency with a simple device structure, and facilitate replacement of a granular ceramic porous body. SOLUTION: This diesel exhaust gas particulate removing device 10 comprises: a body casing 11 provided with a mounting part which enable mounting to an exhaust port of an exhaust system 9 and an emission opening 15 from which a purified gas is emitted to an atmosphere; and a filter case 12 provided with an introducing port 21 for introducing the exhaust gas and a discharge opening 22 for purifying the exhaust gas to discharge to an inside of the body casing 11. An inner cylinder 23 is arranged inside the filter case 12, and has one end which opens to the introducing port 21 and the other end which opens to an inside of the filter case 12. A metal filter is loaded to the inner cylinder 23, and a space between the inner cylinder 23 and the body casing 11 is filled with the granular ceramic porous bodies 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing particulates (fine particles) contained in exhaust gas discharged from a diesel engine in an exhaust system and removing the particulates by oxidation.

[0002]

2. Description of the Related Art Soot (carbon; C) and sulfate (sulfate; Su) are contained in exhaust gas discharged from a diesel engine.
lfate) and other insoluble organic components (Insoluble Organic Fract)
ion) and unburned hydrocarbons (HC) and soluble organic components (S
OF: Soluble Organic Fraction) and the like. These have become social problems that affect the environment and health by being released into the atmosphere. For this reason, regulations that require the installation of a particulate removal device on diesel vehicles have recently been revised.

Hitherto, as a particulate filter for collecting particulates (hereinafter referred to as PM) in an exhaust gas exhaust system, a filter formed by forming a ceramic material into a honeycomb shape is known. As this honeycomb filter, two types of a straight flow type and a wall flow type are generally known. The straight flow type honeycomb filter has a structure in which a large number of cells are formed in a base material, and the cells are separated by thin partition walls. An oxidation catalyst is carried on the surface of the partition wall, and the exhaust gas penetrating the inside of the cell oxidizes the SOF component on the partition wall surface to purify the exhaust gas while contacting the partition wall. (Prior art 1) On the other hand, in a wall flow type honeycomb filter, a base material is made of a porous material, an inlet and an outlet are alternately closed, and exhaust gas passes through a thin porous partition wall. PM is trapped in pores on the surface of the partition and inside the partition. (Prior art 2) This wall flow type honeycomb filter is divided into those in which a catalyst is carried on the surface of the partition walls of the cell and pores in the partition walls, and those in which the catalyst is not carried. In the former case, the collected PM comes into contact with the catalyst,
Oxidized and removed. In the latter, the trapped PM is burned and removed by a burner or a heater.

[0004] An exhaust gas purifying apparatus combining a straight flow type and a wall flow type honeycomb filter is also disclosed (Japanese Patent No. 3012249 (Japanese Unexamined Patent Publication No. Hei 1-318715)). In this device, a straight-flow honeycomb filter is used as an oxidation catalyst for regeneration in an exhaust pipe of a diesel engine, and a wall-flow honeycomb filter is used as a filter for trapping PM downstream of the exhaust gas.

In this apparatus, NO (nitrogen monoxide) in exhaust gas is oxidized by a regeneration oxidation catalyst to produce NO ₂ (nitrogen dioxide) having a strong oxidizing power. On the other hand, in the downstream wall flow type honeycomb filter, PM in exhaust gas
Is trapped, and PM trapped in the filter is oxidized by NO ₂ generated by the regeneration oxidation catalyst to become CO or CO ₂ , so that the PM is reduced. (Prior art 3) Further, in this technique, since the PM accumulated on the filter is continuously reduced, it is prevented that the PM is excessively accumulated and the filter cannot collect PM, and the performance of the filter is reduced. Is maintained. That is, the filter regeneration process is performed continuously.

[0006]

However, the prior art 1 has a problem that soot (carbon C) in PM is discharged to the atmosphere as it is without being oxidized.

Also, PM generated when the temperature of exhaust gas is low, such as when the engine is started, accumulates thickly on the inner wall surface of the cell, and the cell closes to increase the pressure loss. There was a problem that was discharged to the.

In the prior art 2, when the catalyst is not supported on the surface and inside of the cell partition, the PM deposited on the cell partition surface is burned by a burner or a heater. This necessitates additional equipment complexity, failures, and high costs. Furthermore, since a heater is used, PM deposited on the filter causes abnormal combustion, and there is a problem of erosion or cracking of the filter substrate.

When the catalyst is carried on the cell partition, the PM deposited on the filter is oxidized and removed at a relatively low temperature, so that there is an advantage that the base material is not melted or cracked. When the exhaust gas temperature of the engine is low, such as during start-up, low speed, and low load operation, PM is not oxidized, and there is a problem that PM accumulates. further,
Since the exhaust gas passes through the pores of the partition walls, clogging is likely to occur.There is a problem that the clogging causes abnormal increase in the exhaust pressure and an abnormal combustion of the deposited PM due to an increase in the exhaust temperature, thereby causing the filter to be damaged. Was.

[0010] In the prior art 3, since the time the exhaust gas passes through the thin partition walls of the filter is a small quantity, the remaining NO ₂ where NO ₂ is oxidized to the PM without being reduced to NO, is directly discharged to the outside, the environment There was a problem with pollution.

Also, in this filter, when the exhaust gas temperature is low, for example, at 250 ° C. or less, PM is not sufficiently oxidized by NO ₂ , and the PM is deposited on the surface of the partition wall of the filter, and the filter is clogged. Causes a load on the engine. Further, due to the rise in the exhaust gas temperature, abnormal combustion of PM may occur, which may cause a problem that the filter is melted.

As described above, any of the prior arts 1 to 3 has an advantage that when a straight-flow type or wall-flow type honeycomb filter is used, the pressure loss of exhaust gas is small and no load is applied to the engine. There is. On the other hand, a catalyst is supported on each of the above filters, and the PM
However, during operation such as traffic congestion, the temperature of the exhaust gas flowing into the filter is about 200 ° C., so that activation by the catalyst does not proceed. Therefore, PM accumulates in the honeycomb filter or PM However, there is a problem that it is discharged to the outside as it is. In addition, wall-flow filters tend to be clogged because the exhaust gas passes through the pores, which increases the exhaust pressure and puts a burden on the engine. However, this may cause the filter to be damaged. In the straight flow type filter, only the exhaust gas contacting the partition is purified because the catalyst is supported only on the partition surface, and most of the PM does not come into contact with the catalyst and is discharged as it is. .

[0013] Accordingly, the present invention has been made in view of such a conventional disadvantage, and has as its object to provide an apparatus for removing PM in which PM in exhaust gas is collected and oxidized by a filter. .

It is another object of the present invention to provide a particulate removing apparatus that efficiently collects PM and prevents clogging of a filter due to accumulation even when the temperature of exhaust gas is low when the engine is started or the like.

Further, the present invention provides an inexpensive particulate removing apparatus which does not require the use of a burner or a heater for removing PM, has a simple structure, has few troubles, and is easy to maintain. With the goal.

Further, according to the present invention, the rise in exhaust pressure due to clogging of the filter is small, and no load is imposed on the engine.
It is an object of the present invention to provide a particulate removing device in which the temperature of exhaust gas does not rise due to clogging, abnormal combustion of PM due to deposition of PM does not occur, and erosion of a filter due to the above does not easily occur.

[0017]

According to a first aspect of the present invention, there is provided an apparatus for removing fine particles of diesel exhaust gas, comprising: an exhaust system for discharging diesel exhaust gas discharged from a diesel engine into the atmosphere; A device for removing particulates of diesel exhaust gas that is attached near the exhaust port and that is released into the atmosphere after removing particulates from the exhaust gas, wherein an attachment portion that can be attached to the exhaust port of the exhaust system, and particulates from the diesel exhaust gas. A main body casing having a discharge opening for discharging the removed diesel exhaust gas into the atmosphere, an inlet for introducing diesel exhaust gas from the exhaust system, and removing fine particles from the exhaust gas to discharge the exhaust gas into the main body casing. A filter case provided with a discharge port, and an inner cylinder is provided in the filter case. One of the inner cylinders is connected to an exhaust system through an inlet, and the other is opened in a filter case, the inner cylinder is filled with a metal filter, and the inner cylinder is The filter case is filled with a granular ceramic porous body for removing fine particles in exhaust gas. Therefore, according to the first aspect of the present invention, the exhaust gas from the diesel is guided into the inner cylinder from the inlet, and a part of the soot is collected by the metal filter filled in the inner cylinder. After the exhaust gas is collected, the PM is further collected from the end of the inner cylinder through the granular ceramic porous material layer filled between the inner peripheral surface of the filter case and the outer peripheral surface of the inner cylinder. Passes through the discharge port provided on the inlet side, enters the inside of the main body casing from the discharge port, and discharges to the atmosphere from the discharge opening through the space between the inner periphery of the main casing and the outer peripheral surface of the filter case. Will be done.

According to a second aspect of the present invention, in the first aspect, the outlet of the filter case is provided on the inlet side of the filter case.

According to a third aspect of the present invention, in the first aspect, the filter case is detachably attached to the inside of the main body casing through a discharge opening of the main body casing. .

According to a fourth aspect of the present invention, in the first aspect, a through hole having a predetermined size is provided on a side surface of the filter case opposite to the inlet, and the safety valve is formed in a shape covering the through hole. It is characterized by being provided.

According to a fifth aspect of the present invention, in the first aspect, a metal filter is disposed at a portion between the outlet of the filter case and the passage hole.

According to a sixth aspect of the present invention, in the first aspect, a ring-shaped baffle plate is provided between the inner cylinder and the filter case at a predetermined interval and filled with a granular ceramic porous body. It is characterized in that it consists of.

According to a seventh aspect of the present invention, in the first aspect, a flushing port is provided in an attaching portion of the main body casing, and a water draining port is provided in a lower part of an outer periphery of the main body casing. Is characterized in that each port has a removable plug.

[0024] In the invention according to claim 8, in claim 4, the safety valve has a cylindrical shape and a trapezoidal shape provided on one surface of the case. A valve seat composed of a concave portion cut into, a trapezoidal valve, an elastic body locking mechanism erected from the valve, and disposed between the elastic body locking mechanism and the case inner surface. An elastic body that applies a predetermined urging force to the valve, wherein the elastic body is set to such an elastic force that the valve is opened when the exhaust gas pressure received by the valve reaches a predetermined pressure. It is characterized by the following.

According to a ninth aspect of the present invention, in the first aspect, the metal filter has a bulk specific gravity of about 0.8 to 0.1 in a filled state. .

According to the tenth aspect of the present invention, in the first aspect,
, A cylindrical guide plate is provided inside the main body casing for facilitating attachment and detachment of the filter case, and the inner diameter of the guide plate is substantially the same as the discharge port of the main body casing. is there.

According to the eleventh aspect of the present invention, in the first aspect,
In the above, the granular ceramic porous body has a three-dimensional network structure having pores and communication holes.

According to the twelfth aspect of the present invention, the first aspect of the present invention is provided.
In the above, the pore diameter of the granular ceramic porous body is 10
It is characterized in that it is 0 μm to 1000 μm.

According to the thirteenth aspect, in the first aspect,
(1) or (12), wherein the granular ceramic porous body contains silica as a main component.

In the fourteenth aspect of the present invention,
13, the granular ceramic porous body, further, alumina, cordierite, titania, zirconia, silica-alumina, alumina-zirconia, alumina-titania, silica-titania, silica-zirconia, titania-zirconia, mullite One or two or more are contained.

According to the fifteenth aspect, in the eleventh aspect,
In any one of the fourteenth aspect, the granular porous ceramic body has a shape in which pores are exposed on a surface thereof.

According to the sixteenth aspect of the present invention, there is provided the eleventh aspect.
In any one of the fifteenth to fifteenth aspects, the granular ceramic porous body is a catalyst carrying at least one noble metal.

According to the seventeenth aspect, in the eleventh aspect,
15, the granular ceramic porous body may be made of platinum (Pt), palladium (Pd), rhodium (R
h) etc. and at least one noble metal catalyst and cerium oxide;
It is characterized by comprising at least one oxide catalyst such as praseodymium oxide and samarium oxide.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIGS. 1 to 16 are diagrams for explaining a particulate matter removing device for diesel exhaust gas according to a first embodiment of the present invention. Here, FIG.
FIG. 2 is a side view showing the entire diesel particulate removal device. FIG. 2 is a front view showing the diesel particulate removal device. FIG. 3 is a cross-sectional view showing the diesel particulate removal device. FIG. 4 is a sectional perspective view showing a main part of the diesel exhaust gas particulate removing apparatus. FIG. 5 is a perspective view of the filter device and the safety valve of the apparatus for removing particulates of diesel exhaust gas, with essential parts cut away. FIG. 6 is a perspective view showing a main part of a safety valve used in the diesel exhaust particle removing device. FIG. 7 is a cross-sectional view illustrating a main part of a safety valve used in the diesel exhaust particle removing device. FIG. 8 is a sectional view showing the structure of a valve seat of the safety valve. FIG. 9 is a sectional view showing the structure of the safety valve. FIG. 10 is a sectional view showing a locking piece of an elastic body locking mechanism of the safety valve. FIG. 11 is a diagram showing a rod of an elastic body locking mechanism of the safety valve. FIG.
FIG. 3 is a perspective view showing a guide plate for guiding a filter case of the diesel exhaust particle removing device. FIG. 13 is a cross-sectional view showing a state in which the filter case of the device for removing particulates of diesel exhaust gas is housed and mounted in a main body case.
FIG. 14 is a sectional view taken along line AA of FIG. FIG. 15 is a view for explaining a state in which the filter case is detached from the main body casing in the particulate matter removing device for diesel exhaust gas. FIG. 16 is a perspective view showing a state in which the diesel particulate removal device is attached to a diesel vehicle.

As shown in FIG. 16, a diesel exhaust particulate removing apparatus 10 according to an embodiment of the present invention is used after a conventional muffler is removed, and is used to burn fuel in an engine. It is a device that can release the exhaust gas generated by the process into the atmosphere after purification. This diesel exhaust particulate removal device 10
Are roughly divided into a main body casing 11 and a filter case 12 detachably provided in the main body casing 11.

The main body casing 11 includes a main body 13, a mounting portion 14 for attaching to the rear end 8 of the exhaust system 9 of the existing vehicle, and a discharge portion 16 having a discharge opening 15 for discharging exhaust gas to the atmosphere.
These members are formed of a metal plate. The main body 13 is configured to have an elliptical cross section as shown in FIG. 2 and to have a predetermined volume by being formed to a predetermined length L as shown in FIG. . The rear end portion 8 is provided on one side surface of the main body portion 13.
A mounting portion 14 having a diameter similar to the diameter of the exhaust system 9 is provided, and the mounting portion 14 can be attached to the exhaust port at the rear end 8 of the exhaust system 9. The main body 13
As shown in FIGS. 1 and 2, one end of the cylindrical discharge portion 16 is provided on the other side surface. This emission part 1
At the other end of 6, as shown in FIG. 2, a discharge opening 15 having a predetermined diameter D is provided, and the exhaust gas purified from the discharge opening 15 can be discharged to the atmosphere.

The mounting portion 14 of the main casing 11 is provided with a flush port 17 as shown in FIGS. As shown in FIG. 1, a drain port 18 is provided at a lower part of the outer periphery of the main body 13 of the main body casing 11. The flushing port 17 and the draining port 18 are provided with detachable plugs 19 and 20 except at the time of washing. The filter case 12 is formed in a cylindrical shape closed by a metal plate, and has an inlet 21 for introducing exhaust gas from the rear end 8 of the exhaust system 9, and a filter for purifying the exhaust gas to form the main casing 11. A discharge port 22 for discharging the inside is provided. The outlet 22 of the filter case 12
Is provided on the inlet 21 side of the filter case 12, as shown in FIG.

More specifically, the filter case 1
2, an inner cylinder 23 is provided inside the cylinder 2. As shown in FIG. As shown in FIG. 3, one end of the inner cylinder 23 is fixed to an inlet 21, and the inlet 21 is connected to the rear end 8 of the exhaust system 9 via the mounting portion 14. It is like that. The other end of the inner cylinder 23 is open to the inside of the filter case 12. As shown in FIG. 3, the inside of the inner cylinder 23 is filled with a metal filter 25 from the inlet 21 to the other end of the inner cylinder 23. Further, between the outer peripheral surface of the inner cylinder 23 and the inner peripheral surface of the filter case 12 and between the other end of the inner cylinder 23 and the side surface of the filter case 12, The granular ceramic porous body 26 for purifying the exhaust gas is filled over the discharge port 22.

The outlet 2 of the filter case 12
, And through holes 27 formed in the side surface of the filter case 12, metal filters 28, 29 are disposed so that the granular ceramic porous body 26 of the present invention is provided with the outlet 22,
, And through holes 27,. As shown in FIG. 15, the filter case 12 having the above-described structure is detachable from the discharge opening 15 of the main body casing 11 to the inside of the main body casing 11. This filter case 12, as shown in FIG.
Guide plate 3 provided on main body 13 of main body casing 11
0 makes it easily removable.

The guide plate 30 is formed in a hollow cylindrical shape as shown in FIG. 12, and the inside diameter of the cylinder is formed to be the same as the diameter of the discharge opening 15 of the discharge tube 16. As shown in FIG. 13, the guide plate 30 is arranged at a position corresponding to the inner diameter of the discharge cylinder 16 inside the main body casing 11 and fixed to the main body casing 11 by welding or the like. The outer diameter of the filter case 12 is formed slightly smaller than the inner diameters of the guide plate 30 and the discharge cylinder 16.

On the other side of the filter case 12,
As shown in FIG. 13, FIG. 14 and FIG.
1, 31, 31 are planted. The screws 31 and 3 are provided on the side surface of the main body 13 of the main body casing 11.
Mounting holes 32, 32, 3 according to the positions of 1, 31, 31
2, 32 are drilled. The mounting packing 24 is mounted on the screws 31, 31, 31, 31 of the filter case 12. Next, the filter case 12 is inserted into the main casing 11, and the screws 31, 31,
After inserting 31, 31 into the mounting holes 32, 32, 32, 32 on the side surface of the main body 13 of the main body casing 11, nuts 33, 33, 33,
By screwing in at 33, the filter case 12 can be fixed inside the main body casing 11.

The inlet 2 of the filter case 12
As shown in FIG. 5, through holes 27,... Of a predetermined size are provided on the side surface opposite to 1. As shown in FIG. The passage hole 2
7,... Are shaped to be covered by the safety valve 35 as shown in FIGS.

The safety valve 35 includes a case 36 and a valve seat 3.
7, a valve 38, an elastic body locking mechanism 39, and a coil spring 40 which is an elastic body.

More specifically, the case 36
As shown in FIG. 3 and FIG. 5, each is formed in a cylindrical shape having a size to cover the passage holes 27,. The valve seat 37
As shown in FIG. 3 and FIG. 8, each of the cases is formed by a recess provided on one side surface of the case 36 and cut into a trapezoidal shape. As shown in FIGS. 3 and 9, the valve 38 is formed in a trapezoidal disk shape, and has a through hole in the center line thereof. The elastic body locking mechanism 39 is shown in FIGS.
As shown in FIG. 11, a spring receiver 41 provided with a screw along a center line, and a screw rod 42 having both ends threaded.
And a nut 43 screwed onto the screw rod 42. A screw rod 42 is screwed into the spring receiver 41, and the screw rod 42 is
, The coil spring 40 is brought into contact with the spring receiver 41, the screw rod 42 is inserted from the back side of the valve seat 37, the screw rod 42 is inserted through the center hole of the valve 38, and the screw rod 42 is inserted.
By screwing the nut 43 into the guide plate 30, the guide plate 30 as shown in FIG. 3 is formed.

The coil spring 40, which is an elastic body, is disposed between the spring receiver 41 of the elastic body locking mechanism 39 and the inner surface of the case 36 on the back side of the valve seat 37. The coil spring 40 is set to have such an elastic force that the valve 38 is opened when the exhaust gas pressure received by the valve 38 reaches a predetermined pressure.

The filter case 1 is disposed between the outer peripheral surface of the inner cylinder 23 and the inner peripheral surface of the filter case 12.
When the granular ceramic porous body 26 of the present invention fills from 2 to the discharge port 22, as shown in FIG. 3 and FIG. Ring-shaped baffle plate 45, 46, 45, 4
Place 6, ... In addition, one ring-shaped baffle plate 45
Is formed in such a size that its outer periphery is in contact with the inner peripheral surface of the filter case 12. Another ring-shaped baffle 4
Reference numeral 6 denotes a size whose inner circumference is in contact with the outer circumference of the inner cylinder 23. Further, it is desirable that the ring-shaped baffle plates 45 and the ring-shaped baffle plates 46 are alternately arranged at predetermined intervals, and they should not be arranged too densely.

Further, the apparatus 10 for removing particulates from diesel exhaust gas of the present invention, as shown in FIG. 1, FIG. 3 and FIG.
By connecting the connection flange 50 to the connection flange 49 of the rear end 8 of the exhaust system 9 via the packing 48, inserting the bolt 51 into the connection flange 49, 50, and screwing the nut 52 to the bolt 51, Connected to the exhaust pipe. Further, the apparatus 10 for removing particulates from diesel exhaust gas of the present invention is fixed to a vehicle body by a mounting bracket 55.

The operation of the apparatus 10 for removing particulates from diesel exhaust gas according to the present invention will be described below.

As shown in FIG. 3, the exhaust gas from the engine passes through the rear end portion 8 of the exhaust system 9 and is introduced into the inner cylinder 23 from the mounting portion 14 and the inlet 21 to the inside of the inner cylinder 23. Soot and the like are collected by the filled metal filter 25.

As shown in FIG. 3, the exhaust gas from which soot and the like are partially collected by the metal filter 25 flows from the end of the inner cylinder 23 to the inner peripheral surface of the filter case 12 and the outer periphery of the inner cylinder 23. Through the granular ceramic porous body 26 of the present invention filled between the surfaces, it is further collected and passes toward the outlet 22 provided on the inlet 21 side, and from the outlet 22 the main body 13 of the main body casing 11 Through the space between the inner periphery of the main body 13 of the main body casing 11 and the outer peripheral surface of the filter case 12, and is discharged to the atmosphere from the discharge opening 15 of the discharge cylinder 16.

Here, when the accelerator is depressed and the engine is rapidly rotated at a high speed, the exhaust gas pressure in the inner cylinder 23 sharply increases, but the pressure received by the valve 38 increases, and the elastic force of the coil spring 40 overcomes. Since the valve 38 is opened, the exhaust gas passes through the metal filter 25 of the inner cylinder 23 and the metal filter 2.
9, the gas passes through the passage hole 27 and the valve seat 37, and is discharged to the atmosphere from the discharge opening 15 of the discharge cylinder 16, so that the influence on the engine can be reduced. At this time, the exhaust gas is discharged without being purified, but the pressure difference immediately disappears, and the exhaust gas returns to the original purified state.

The first embodiment has the following advantages because it has the above-described structure and has the above-described functions. (1) The structure is simple and lightweight, and can be provided at low cost. (2) Since the discharge opening of the discharge cylinder is open to the atmosphere, no exhaust gas leaks from the main body casing. (3) The exhaust gas can be efficiently and reliably purified by oxidizing and removing PM with a catalyst. (4) A simple configuration without a mechanism such as a heater and no maintenance is required. (5) Maintenance can be easily performed because the metal filter and the like inside the device for removing particulates of diesel exhaust gas can be easily washed by opening the water washing mouth and the water draining mouth. (6) The filter case can be easily removed from the main body casing, the filter case can be easily mounted on the main body casing, and the granular ceramic porous body of the present invention can be easily replaced. (7) Since the safety valve is attached, even when a pressure load is applied to the exhaust gas, a part of the exhaust gas is discharged, so that no burden is imposed on the engine.

[Second Embodiment] FIG. 17 is a block diagram showing an apparatus for removing fine particles of diesel exhaust gas according to a second embodiment of the present invention. FIG. 18 is a side view showing the diesel particulate removal device.

As shown in FIGS. 17 and 18, in the diesel particulate removal apparatus 10a according to the second embodiment, the main body portion 13a of the main body casing 11a has a size in which the two filter cases 12, 12 can fit. And a mounting portion 14a is formed at one portion attached to the exhaust port of the rear end portion 8 of the exhaust system 9 and at a forked portion attached to the introduction ports 21 and 21 of the filter case 12, and the discharge cylinder 16 is formed at one end. It has a structure provided.

The operation and effect similar to those of the above-described first embodiment can be achieved by the diesel particulate removal device 10a according to the second embodiment.

Further, according to the apparatus 10a for removing particulates from diesel exhaust gas according to the second embodiment, it is possible to purify exhaust gases of vehicles having a large displacement.

[Others] The second embodiment may have a configuration in which two filter cases 12 are provided, or a configuration in which three or more filter cases 12 are provided.

[Granular Ceramic Porous Body of the Present Invention] The granular ceramic porous body of the present invention is described in, for example, JP-A-8-1415.
89 can be made. According to this method, a spherical thermoplastic resin is added to the ceramic raw material,
Add water and binder and mix into a paste with a kneader,
When the volume part of the composition is occupied by the spherical thermoplastic resin, and the formed fired material is heated to 80 ° C. to 240 ° C. in the first-stage drying, the spherical thermoplastic resin is converted into the fired material matrix in the first-stage drying. Fixed inside, creating a basic skeleton. That is, large pores are formed in this step.

Thereafter, by heating to 240 ° C. to 500 ° C. in the second stage of drying, the spherical thermoplastic resin is melted at this stage, flows between the ceramic raw material particles while decomposing, and small pores are formed. Is done. In this step, a part of the ceramic raw material including the spherical thermoplastic resin is melted,
Air is supplied from the spherical thermoplastic resin and sintered to form a ceramic porous body while maintaining large and small pores.
When a large-sized spherical resin is used, large pores can be obtained, and when a small-sized one is used, small pores can be obtained. Can be manufactured. The large and small pores artificially created in this way are exposed, and therefore, an uneven surface is formed on the surface of the granular ceramic porous body. In the ceramic, there are a large number of communication holes penetrating vertically and horizontally, and a large number of swelling spaces (so-called large and small pores artificially created as described above) in the middle of the communication holes. The gap formed by contacting the granular ceramic porous bodies serves as an exhaust gas passage.

The exhaust gas passing through the packed layer of the granular porous ceramics flows through the gap so as to surround each of the granular porous ceramics, and PM has a large chance of contact with the surface of the granular ceramic porous body. Due to the pressure, PM can easily penetrate into the air-permeable granular ceramic porous body, and the penetrated PM causes the exhaust gas to stay in the pores, so that the PM is easily adsorbed to the pore inner wall.

As described above, since each of the granular ceramic porous bodies has excellent trapping ability, it also has a function as a PM combustion field described below.

The exhaust gas temperature is usually 1 near the outlet of the exhaust pipe.
In the range of 50C to 400C, this temperature depends on the load on the engine. In other words, when idling,
The temperature is of the order of 150 ° C. and can reach 400 ° C. or more at the maximum engine load.

In order to oxidize and burn PM trapped in the granular ceramic porous body at the exhaust gas temperature, the exhaust gas temperature is low when the exhaust gas temperature is in the above-mentioned range of 150 to 400 ° C. For example, the PM combustion zone in an air atmosphere is low. , 600 ° C. or higher. On the other hand, by supporting a noble metal catalyst, for example, Pt (platinum) on the granular porous ceramic body, the combustion temperature of PM collected by the ceramic can be reduced. The combustion temperature of the granular ceramic porous body carrying platinum starts at around 250 ° C. Therefore, if platinum is carried on the granular ceramic porous body, oxidizing combustion can be sufficiently performed at the exhaust gas temperature.

Since the reaction of the catalyst is activated only on the surface thereof, it is important to efficiently capture PM on the surface of the granular ceramic porous body. In that regard, the structure of the granular ceramic porous body according to the present invention is effective. Further, by supporting platinum on the granular ceramic porous body, NO generated in the engine is oxidized on the surface of the granular ceramic porous body to become NO ₂ , and PM is burned by the NO ₂ .
Here, of the NOx generated by combustion of the engine,
_Since there is little ₂ , NO ₂ is generated by the oxidation reaction with the catalyst. This NO ₂ has excellent oxidizing power.

The catalyst to be supported on the granular ceramic porous body is one of a noble metal catalyst such as platinum (Pt), palladium (Pd) and rhodium (Rh) and an oxide catalyst such as cerium oxide, praseodymium oxide and samarium oxide, or one of these. A combination, preferably platinum (Pt),
Other noble metal catalysts of Pt may be used.

Ceramic raw materials for forming the granular ceramic porous body include silicate minerals such as silica, silica silicate, and diatomaceous earth; alumina minerals such as diaspore, bauxite, and fused alumina; and silica alumina minerals such as clay. Mineral limestone and wollastonite, such as kaolin-like kibushi clay and frog-eye clay, or montmorillonite-like bentonite, roesite and sillimanite minerals, as well as magnesite minerals such as magnesite and dolomite. Other minerals include chromite ore such as chromite ore, spinel, zirconia ore such as zircon and zirconia, and other minerals such as titania mineral and carbonaceous mineral graphite.

Also, artificial ceramic raw materials other than natural minerals, for example, zirconia, silicon nitride, titania, electrolytic corrosion alumina, synthetic magnesia, synthetic dolomite, synthetic mullite and the like can be used. These ceramic raw materials are used alone or in the form of a powder as in the case of ordinary refractory production.

The particle size of the granular porous ceramic of the present invention is as follows:
It is 5 mm to 20 mm, preferably about 10 mm. If the particle size is less than 5 mm, the exhaust pressure will increase and a load will be placed on the engine. If the particle size exceeds 10 mm, the PM collection efficiency will decrease.

When the particulate ceramic porous body of the present invention carries a catalyst made of a noble metal, PM is adsorbed on the ceramic surface or the inner wall surface, combustion starts at the temperature of the exhaust gas, and the deposition of PM does not occur before the deposition. , Will be removed. In the pores, since the almost closed space and the ceramic have low thermal conductivity, combustion heat tends to be trapped and more easily propagated, and further develops combustion, and combustion inside the granular ceramic porous body is performed efficiently. Will be

[0071]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the apparatus 10 for removing particulates from diesel exhaust gas according to the first embodiment, the outer diameter of the inner cylinder 23 is about 8 cm, and the outer diameter of the filter case 12 is about 13 cm.
Inner diameter of main body casing 11: about 15 [cm], length L of main body casing 11: about 35 [cm], thickness of granular ceramic porous body 26: about 2.5 [cm], outer diameter of discharge cylinder 16: In the diesel exhaust particle removing device 10 composed of about 13.5 [cm] and the length of the discharge cylinder 16: about 25 [cm],
As the granular ceramic porous body 26, "Nagao Posel SG1" (product name) manufactured by Nagao Co., Ltd. was filled with about 2 liters each.

This diesel exhaust particulate removing device 1
0 equipped with Mitsubishi Motors truck, motor model: 4D32, maximum output: 81 (110) / 3500
[Kw (PS) / min ^-1 ], model: U-FE305B, cycle: 4, cylinder: 4, cylinder diameter x stroke: 104.0 x 1
05.0 [mm], compression ratio: 17.5, total displacement 3.56
7 [L] was subjected to a no-load rapid acceleration operation and measured by an exhaust smoke concentration measurement device (GSM-2 manufactured by Iyasaka Co., Ltd.).

[0073]

[Table 1] Table 2 shows the measurement results in the case where the device 10 for removing particulates of diesel exhaust gas was not installed under the same conditions.

[0074]

[Table 2] In Tables 1 and 2, the degree of contamination was 26 in Table 2 on average.
What was [%] is changed to 10 [%] in Table 1, and it can be seen that the exhaust gas smoke is reliably removed by the diesel exhaust particulate removing device 10 according to the embodiment of the present invention.

The granular ceramic porous material “Nagao Pocell SG1” (product name) manufactured by Nagao Co., Ltd. used in the present invention.
The outline of is as follows.

The composition components of the granular semimic porous material were, in terms of% by weight, SiO ₂ 88.9, Al ₂ O ₃ 7.6, Fe ₂ O ₂ 0.3, and K ₂ O 2.
0, Na ₂ O ₂ 0.8, TiO ₂ 0.2, CaO 0.1, and MgO 0.1. The particle diameter was 5 to 10 mm, the porosity was 74%, the specific surface area was 1 m ² / g, and the average pore diameter was 500 μm.

The metal filters 25, 28, 29 used in the apparatus for removing particulates from diesel exhaust gas according to the present invention.
Is as follows. Material: Stainless steel, Shape: Double coil shape, diameter is about 5 [mm], Cross section: rectangular shape.
8 [mm] (width) x 0.1 [mm] (thickness).
Further, the metal filters 25, 28, and 29 have a large elasticity and can be packed in a large amount, and also have voids. Further, the metal filters 25, 28, and 29 had a large surface area and could be trapped by PM adhesion.

The metal filters 25, 28, 29
The bulk specific gravity is about 0.3 when filled in the filter case 12 of the present invention made of the inner cylinder 23 and the granular ceramic porous body, and is very light. Metal filters 25, 28, 29
Is formed in a double coil shape, the exhaust resistance is small, no exhaust pressure is applied, and no load is applied to the engine.

The safety valve 35 is as follows. It does not work when idling. The engine load is 1 [k
g / cm ² ], the safety valve 35 operates. It can also be adjusted.

The filter case 12 was opened on the side surface.
The passing holes 27,.
Drilled. Thereby, the total area of the passage hole 27 is 3.9.
[cm ^2]Becomes The area of the gap of the valve 38 is 0.63.
[cm^Two ].

The elastic force of the coil spring 40 is such that the exhaust resistance is 1
When the pressure exceeds [kg / cm ² ], the valve 38 of the safety valve 35 is set to open.

[0082]

As described above, according to the present invention, a main body casing which can be attached to an exhaust port of the exhaust system and has a discharge opening for discharging purified gas into the atmosphere, A filter case provided with an inlet for introducing the exhaust gas from the filter, and an outlet for purifying the exhaust gas and discharging the exhaust gas into the main body casing, wherein an inner cylinder is provided in the filter case, One is connected to the exhaust system through the inlet and the other is opened in the filter case, the inner cylinder is filled with a metal filter, and the space between the inner cylinder and the filter case is Is filled with the granular ceramic porous body of the present invention, which is composed of a granular ceramic porous body that purifies exhaust gas, and has the following advantages.

(1) The structure is simple and lightweight, and can be provided at low cost. (2) Since the discharge opening of the discharge cylinder is open to the atmosphere, no exhaust gas leaks from the main body casing. (3) The exhaust gas can be efficiently and reliably purified by oxidizing and removing PM with a catalyst. (4) A simple configuration without a mechanism such as a heater and no maintenance is required. (5) Maintenance can be easily performed because the metal filter and the like inside the device for removing particulates of diesel exhaust gas can be easily washed by opening the water washing mouth and the water draining mouth. (6) The filter case can be easily removed from the main body casing, the filter case can be easily mounted on the main body casing, and the granular ceramic porous body of the present invention can be easily replaced. (7) Since the safety valve is attached, even when a pressure load is applied to the exhaust gas, a part of the exhaust gas is discharged, so that no burden is imposed on the engine.

[Brief description of the drawings]

FIG. 1 is a side view showing an entire diesel particulate removal apparatus according to an embodiment of the present invention.

FIG. 2 is a front view showing the device for removing fine particles of diesel exhaust gas.

FIG. 3 is a cross-sectional view showing the diesel particulate removal device.

FIG. 4 is a cross-sectional perspective view showing a main part of the diesel particulate removal device.

FIG. 5 is a perspective view showing a filter case and a safety valve of the diesel exhaust gas particulate removing device, in which main parts of the filter case are cut away.

FIG. 6 is a perspective view showing a main part of a safety valve used in the diesel exhaust particle removing device.

FIG. 7 is a cross-sectional view showing a main part of a safety valve used in the diesel exhaust particle removing device.

FIG. 8 is a sectional view showing a structure of a valve seat of the safety valve.

FIG. 9 is a cross-sectional view showing the structure of the safety valve.

FIG. 10 is a sectional view showing a locking piece of an elastic body locking mechanism of the safety valve.

FIG. 11 is a view showing a rod of an elastic body locking mechanism of the safety valve.

FIG. 12 is a perspective view showing a guide plate for guiding a filter case of the particulate matter removal device for diesel exhaust gas.

FIG. 13 is a cross-sectional view showing a state in which a filter case of the diesel particulate removal device is housed and mounted in a main body case.

FIG. 14 is a sectional view taken along line AA of FIG.

FIG. 15 is a view for explaining a state in which the filter case is detached from the main body casing in the apparatus for removing fine particles of diesel exhaust gas.

FIG. 16 is a perspective view showing a state in which the diesel particulate removal device is attached to a vehicle.

FIG. 17 is a configuration diagram illustrating an apparatus for removing particulates from diesel exhaust gas according to a second embodiment of the present invention.

FIG. 18 is a side view showing the diesel particulate removal device.

[Explanation of symbols]

 10, 10a Diesel exhaust particulate removal device 11, 11a Main body casing 12 Filter case 13, 13a Main body 14, 14a Attachment 15 Release opening 16 Release cylinder 17 Rinse mouth 18 Drain 21 Inlet 22 Outlet 23 Inner cylinder 25, 28, 29 Metal filter 30 Guide plate 35 Safety valve 36 Case 37 Valve seat 38 Valve 39 Elastic body locking mechanism 40 Coil spring 41 Spring receiver 45, 46 Ring-shaped baffle plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01N 3/18 F01N 3/24 E 3/24 B01D 46/42 B // B01D 46/42 53/36 104B 104A 101Z (72) Inventor Yoshihisa Kumai 302 F, Term, Niibori, Kawaguchi City, Saitama Prefecture AA06 AA14 AB01 AB06 BA01X BA02X BA03X BA06X BA07X BA08Y BA10X BA14X BA18Y BA30Y BA31Y BA32Y BA33Y BA34Y BA36X BA41Y BA42Y BB09 CC41 4D058 JA02 JA60 JB03 JB06 JB24 JB33 MA44 SA08

Claims (17)

[Claims] A diesel particulate removal device attached near an exhaust port of an exhaust system for releasing diesel exhaust gas discharged from a diesel engine to the atmosphere, removing particulates from the exhaust gas, and then releasing the exhaust gas to the atmosphere, A mounting portion capable of being attached to an exhaust port of the exhaust system, and a main body casing provided with a discharge opening for discharging diesel exhaust gas in which particulates have been removed from diesel exhaust gas to the atmosphere; and a diesel exhaust gas from the exhaust system. An inlet for introduction, and a filter case provided with an outlet for removing fine particles from the exhaust gas and discharging the exhausted gas into the main body casing, wherein an inner cylinder is provided in the filter case, and the inner cylinder is provided. One is connected to the exhaust system via the inlet and the other is open to the filter case. The inner cylinder is filled with a metal filter, and between the inner cylinder and the filter case, a granular ceramic porous body for removing fine particles in exhaust gas is filled. For removing particulates from diesel exhaust. 2. The apparatus according to claim 1, wherein an outlet of the filter case is provided on an inlet side of the filter case. 3. The filter case according to claim 1, wherein the filter case is detachably attached to the inside of the main body casing from a discharge opening of the main body casing.
An apparatus for removing particulate matter from diesel exhaust gas as described in the above. 4. A filter according to claim 1, wherein a through hole having a predetermined size is provided on a side surface of said filter case opposite to the inlet, and a safety valve is provided in a shape covering said through hole. An apparatus for removing particulate matter from diesel exhaust gas as described in the above. 5. An apparatus for removing particulates from diesel exhaust gas according to claim 1, wherein a metal filter is disposed at a portion between the outlet of the filter case and the passage hole. 6. The filter according to claim 1, wherein a granular ceramic porous body is filled between said inner cylinder and said filter case, and ring-shaped baffles are arranged at predetermined intervals. Item 2. The particulate matter removing device for diesel exhaust gas according to Item 1. 7. A water washing mouth is provided at an attaching portion of the main body casing, and a water drainage mouth is provided at a lower part of an outer periphery of the main body casing. The apparatus for removing particulates from diesel exhaust gas according to claim 1, wherein 8. The safety valve according to claim 1, wherein the valve has a cylindrical shape and a size that covers the passage hole, and a trapezoidal concave portion provided on one surface of the case. A valve having a trapezoidal shape, an elastic body locking mechanism erected from the valve, and an elastic body arranged between the elastic body locking mechanism and the inner surface of the case to apply a predetermined urging force to the valve. 5. The diesel exhaust gas according to claim 4, wherein the elastic body is set to such an elastic force that the valve is opened when the exhaust gas pressure received by the valve reaches a predetermined pressure. 6. Particle removal equipment. 9. The apparatus for removing particulate matter from diesel exhaust gas according to claim 1, wherein the bulk density of the metal filter in a filled state is about 0.8 to 0.1. 10. A cylindrical guide plate for facilitating attachment and detachment of the filter case is provided inside the main body casing,
2. The apparatus according to claim 1, wherein the inner diameter of the guide plate is substantially the same as the discharge port of the main casing. 11. The diesel particulate removal apparatus according to claim 1, wherein the granular ceramic porous body has a three-dimensional network structure having pores and communication holes. 12. The apparatus for removing fine particles of diesel exhaust gas according to claim 11, wherein the pore diameter of the granular ceramic porous body is 100 μm to 1000 μm. 13. The diesel particulate removal device according to claim 11, wherein the granular ceramic porous body contains silica as a main component. 14. The granular ceramic porous body further comprises alumina, cordierite, titania, zirconia, silica-alumina, alumina-zirconia, alumina
The particulate matter removal device for diesel exhaust gas according to any one of claims 11 to 13, wherein one or more of -titania, silica-titania, silica-zirconia, titania-zirconia, and mullite are contained. . 15. The apparatus for removing particulates from diesel exhaust gas according to claim 11, wherein the granular ceramic porous body has a shape in which pores are exposed on the surface. 16. The diesel particulate removal device according to claim 11, wherein the granular ceramic porous body is a catalyst supporting at least one noble metal. 17. The granular ceramic porous body includes at least one of a noble metal catalyst such as platinum (Pt), palladium (Pd) and rhodium (Rh) and at least one of an oxide catalyst such as cerium oxide, praseodymium oxide and samarium oxide. The diesel particulate removal device according to any one of claims 11 to 15, comprising one type.