JP3438316B2 - Exhaust gas purification device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for collecting particulates such as carbon, smoke and soot contained in exhaust gas discharged from a diesel engine and heating and incinerating the particulates.

[0002]

Conventionally, the carbon from the exhaust gas of diesel engines, soot, as particulate i.e. material of the exhaust gas treatment filter for collecting particulate matter such as HC is cordierite (2MgO · 2Al ₂ O ₃・ 5S
Filter iO ₂₎ made of honeycomb shape is used. The filter may be a wall-type exhaust gas treatment filter aiming at a trapping effect when passing through a porous wall, or a three-dimensional reticulated honeycomb or foamed ceramic. An exhaust gas treatment filter using a porous body is disclosed.

Further, Japanese Patent Application Laid-Open No. 57-163112 discloses a treatment device for exhaust fine particles of a diesel engine. The exhaust particulate treatment device is provided with a filter in which at least two reticulated or porous metal sheets are wound in a foamed ceramic foam so as to be adjacent to each other at an interval in an exhaust passage of a diesel engine,
So that the exhaust gas passes through the ceramic foam,
A voltage is applied to each of the metal sheets as positive and negative electrodes.

Further, in Japanese Patent Laid-Open No. 5-44441,
A particulate purification filter device is disclosed. The particulate purification filter device is configured to be able to heat the filter in order to burn and remove particulates collected by the filter, and has a heater in which a resistance value in both end regions of the filter is set lower than a resistance value in a central region. .

Further, Japanese Patent Application Laid-Open No. 58-193714 discloses an exhaust gas purifying structure. The exhaust gas purifying structure includes a fiber filter installed in an exhaust system to collect fine particles in the exhaust gas, and a honeycomb structure covering the exhaust gas outlet side and the inlet side of the fiber filter,
Two or more fiber filters are provided in the exhaust gas flow direction.

Further, Japanese Patent Laid-Open No. 59-138712 discloses a fine particle collecting device. The fine particle collecting device includes a ceramic carrier and a heater wire, and the heater wire has a coating layer of a ceramic material attached and formed around a metal wire.

[0007]

The effect of the diesel particulate filter has been confirmed especially as a device for removing black smoke in the exhaust gas of a diesel engine. However, the conventional cordierite honeycomb filter has a low porosity, and the filter tends to become large in order to secure a passage area. As the filter becomes larger, the heat capacity becomes larger and the heating of the filter becomes larger. Since the power required for regeneration cannot be supplied, there is no choice but to use the combustion propagation method. As a result, when the filter is heated and regenerated, particulates accumulate on the areas where combustion propagation is insufficient, and sometimes the temperature becomes too high and abnormal combustion occurs, which causes melting and damage of the filter, and the life of the filter. Causes a problem that the durability of the filter is shortened.
Alternatively, the combustion propagation may become non-uniform, which may cause clogging of the filter, gradually increase the pressure loss, raise the exhaust pressure of the engine, and deteriorate the performance.

Further, in the exhaust fine particle processing apparatus disclosed in the above-mentioned Japanese Patent Laid-Open No. 57-163112, the heater is constituted by a wire mesh, but the function of retaining the shape of the felt constituting the filter by the wire mesh is not provided. I do not have it. Further, in the particulate purification filter device disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-44441, a heater is arranged with respect to the filter, but the heater is arranged on the outer peripheral surface of the filter, and mainly the particulates. Is heated and burned by combustion propagation, and the above problems occur.

In the exhaust gas purifying structure disclosed in Japanese Patent Laid-Open No. 58-193714, the fiber filter is sandwiched between the honeycomb structures, but the felt forming the filter is retained by the wire mesh. It does not have the function. Furthermore, the above-mentioned JP-A-59-13871.
The fine particle collecting device disclosed in Japanese Patent No. 2 discloses that the heater is coated with ceramics.
Specifically, it is a zirconia sprayed and coated, and when sprayed on the wire net, there is a problem that the overlapping region of the wire net is not coated.

An object of the present invention is to solve the above problems, and is used by incorporating it into an exhaust system for purifying exhaust gas discharged from a diesel engine,
This is an exhaust gas purifying device that collects particulate matter such as carbon, soot, and HC contained in exhaust gas discharged from a diesel engine, that is, particulates. The filter is made of ceramic fiber into a felt, and the shape of the felt is formed. The shape is maintained by a wire mesh and a metal plate that can be energized, and the shape of the felt is formed by a wire mesh to improve air permeability and to uniformly heat the particulates during heating and burning. It is an object of the present invention to provide an exhaust gas purification device that is compact and lightweight.

[0011]

SUMMARY OF THE INVENTION The present invention, in the exhaust gas purifying apparatus for heating incinerated by collecting particulates contained in the exhaust gas is disposed in an exhaust system of a diesel engine, it is integrated into the exhaust system filter for collecting the particulate matter located within the casing contained and in the exhaust gas is constituted by energizable wire mesh that holds sandwiching the felt and the felt composed of short fibers of ceramic fiber, the filter is The exhaust gas
The fibers are sequentially folded back in parallel with the flow direction of
Both ends of the filter are welded to the wire mesh by the first metal plate.
The second metal plate that is sealed and covers the first metal plate is
Welding to the first metal plate to maintain the shape of the filter
The wire mesh is energized to heat the filter .
The exhaust gas purifying apparatus is characterized in that the particulate matter collected by the filter is incinerated by heating to regenerate the filter.

[0012] wherein the first metal plate and the second metal plate is composed of metal or Ni plate of the metal mesh of the same material, the first metal plate, said second metal plate and the metal mesh The second metal plate is electrically connected and can be used as an electrode.

Since the exhaust gas purifying apparatus is constructed as described above, the filter is heated by energizing the wire net, and the particulates collected in the filter are incinerated by heating to regenerate the filter. To be done . Since the filter is composed of the felt made of ceramic fibers and does not constitute a structure such as a honeycomb, the particulates in the exhaust gas are evenly collected by the felt, and the particulates in the exhaust gas are collected. Abnormal combustion or the like does not occur in the felt during heating and incineration, and the durability of the filter is improved and the service life is extended. Moreover,
The felt is formed in a tubular shape surrounded by the wire mesh, and since the wire mesh is energized, the shape-retaining material is composed of the wire mesh to improve air permeability, and the felt is uniformly heated. The particulates can be incinerated to regenerate the filter, the filter is prevented from being melted and the abnormal deformation of the filter due to thermal stress is prevented, the durability of the filter is improved, and the particulates are improved. Are uniformly burned and burned in a short time, the filter is regenerated, and no unburned particulate remains in the filter.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an exhaust gas purifying device according to the present invention will be described below with reference to the drawings. Further, in the drawings referred to below for explaining the various embodiments, the components having the same functions are denoted by the same reference numerals, and redundant description will be omitted.

The exhaust gas purification system shown in FIG. 1 is used by incorporating it into an exhaust system of a diesel engine 90, and is composed of a filter 1 arranged in a case 2 incorporated in an exhaust passage 5, and the exhaust gas is removed by the filter 1. Particulates such as soot, carbon, and smoke contained therein are collected, and clean exhaust gas in which the particulates are collected is discharged to the outside through the outlet side exhaust passage 6. An exhaust manifold 91 attached to the diesel engine 90 is provided with a turbocharger 92. Turbine 93 of turbocharger 92
The outlet is connected to the inlet side exhaust passage 5 through the exhaust pipe 94.

The filter 1 collects particulates such as carbon, soot, HC, and black smoke in the exhaust gas in the case 1, and the collected particulates are heated and incinerated by the filter 1, but are collected by the filter 1. In order to burn and incinerate the collected particulates by heating and burning, an electric circuit 11 leading to a controller 10 provided with a DC power source as a means for energizing the filter 1 is provided. Further, in this exhaust gas purifying device, a sensor 17 is installed in the inlet side exhaust passage 5 to detect the exhaust pressure, the gas temperature and the amount of particulates.
Is installed, and a sensor 18 is installed in the outlet side exhaust passage 6. Further, in order to measure the temperature of the central portion of the filter 1, a temperature sensor 19 is incorporated in the filter 1.

This exhaust gas purifying apparatus is incorporated in an exhaust gas purifying system, and is disposed in the case 2 and the case 2 incorporated in the exhaust passages 5 and 6, respectively, at both ends of the filter 1 and the filter 1. It has the electrode part 7 provided. The filter 1 is composed of a felt 8 formed in a tubular shape from short-fiber ceramic fibers. The felt 8 is a ceramic felt made of aluminum oxide and silicon oxide, and has a basis weight (weight per unit area) of 400 g / m ² . Off Eruto 8, both end portions is sealed with an insulating sealing plate 15, the outer peripheral surface is surrounded by a wire mesh 4 which is made from a refractory metal. Wire mesh 4 is F with wire diameter of 0.5 mm
It is made of a material equivalent to CH1 material. Also, full Eruto 8 which is shape-retaining wire gauze 4, hollow support cylinder 3 made of a porous metal material or a wire mesh having a number of through holes 16
Are arranged on the outer peripheral surface of. Thus, full Eruto 8 has its external shape by a wire mesh 4 to the outer covering is shape-retaining in tubular, inside which inner shape is the shape retaining by the support cylinder 3.

The supporting cylinder 3 is provided with an end plate 14 for closing the upstream side of the exhaust gas flow, and a flange 13 for fixing the downstream side to the case 2. Case 2
By installing the filter 1 inside, an inlet side annular passage 9 is formed between the inner surface of the case 2 and the outer surface of the filter 1, and an outlet side passage 12 is formed in the hollow portion of the support cylinder 3. The inlet side annular passage 9 communicates with the inlet side exhaust passage 5, and the outlet side passage 12 communicates with the outlet side exhaust passage 6. Further, the wire net 4 arranged on the outer peripheral surface of the felt 8 is provided with electrode portions 7 at both ends of the wire net 4 in order to pass an electric current through the wire net 4.

Next, the operation of the exhaust gas purifying apparatus will be described. The diesel engine 90 is started and the exhaust gas exhausted from the diesel engine 90 drives the turbine 93 of the turbocharger 92. Exhaust gas passes from the outlet of the turbine 93 through the exhaust pipe 94 to the exhaust passage 5
Sent to. Next, the exhaust gas is sent from the exhaust passage 5 into the filter 1 through the inlet-side annular passage 9. In the filter 1, the exhaust gas passes through the holes of the wire net 4 into the felt 8, and at that time, the felt 8 collects particulates such as carbon, soot, and smoke contained in the exhaust gas, and becomes clean. Exhaust gas flows from the through hole 16 of the support cylinder 3 to the outlet side passage 12, and then is discharged to the outside through the outlet side exhaust passage 6. Therefore,
When a predetermined amount of particulates is collected by the filter 1, electric power is supplied from the DC power supply to the electrode portion 7 through the electric circuit 11, and the wire net 4 is energized. When the wire net 4 is energized, the filter 1 is heated, the particulates collected in the felt 8 are heated and incinerated, and the filter 1 is regenerated.

In order to compare the function of the exhaust gas purifying apparatus according to the present invention with that of the conventional exhaust gas purifying apparatus, FIGS.
An exhaust gas purifying device including a comparative product, that is, a porous filter as shown in FIG.

The exhaust gas purifying apparatus of the comparative product shown in FIGS. 4 and 5 is configured to be used by incorporating it into the exhaust gas purifying system shown in FIG. 1, and is made of cordierite in the case 2. The porous filter 71 is incorporated. The porous filter 71 is formed in a honeycomb structure having the same collection area, and is arranged in the case 2 with a seal member 72 interposed between the porous filter 71 and the case 2. Further, a heater coil 74 is provided on the upstream side of the porous filter 71, and the heater coil 74 is configured to be electrically heated through a terminal 77. The exhaust gas is sent from the inlet side passage 5 to the inlet side passage 73 of the porous filter 71, passes through the porous filter 71 from the inlet side passage 73 and is exhausted to the outlet side passage 75, and then from the outlet side passage 75 to the outlet. The gas is exhausted to the outside through the side exhaust passage 6.

Next, in order to compare the exhaust gas purifying apparatus according to the present invention (hereinafter referred to as the product of the present invention) with the exhaust gas purifying apparatus shown in FIG. 4 (hereinafter referred to as the comparative product), both are operated and the diesel engine is operated. The collection efficiency of particulates exhausted from 90, the pressure loss of the filter and the regeneration time of the filter were measured. The results, are shown in FIG. 6, 7 and 8.

The product of the present invention has almost the same collection efficiency (%) as shown in FIG. 6 as compared with the comparative product, but the increase of the pressure loss is slower as shown in FIG. I understand. Therefore, if the collection time between the product of the present invention and the comparative product is constant, the collection area of the product of the present invention is 1/5 of the collection area of the comparative product by analogy with the pressure loss shown in FIG. Therefore, it can be seen that the product of the present invention may be made compact and lightweight as compared with the conventional exhaust gas purifying device. Further, in the regeneration test after collecting particulates of the product of the present invention and the comparative product, the temperature (° C.) of the center of the filter was measured by the temperature sensor 19 incorporated in the filter. As can be seen from the temperature rise characteristics shown in FIG. 8, in the product of the present invention, as compared with the comparative product, the temperature of the filter itself rises more rapidly, and the regeneration is completed quickly. That is, in the product of the present invention, the particulates are heated and burned at the elapsed time of 3 to 4 minutes, while the comparative product is heated and burned at the elapsed time of 8 to 10 minutes. Is being played. That is, it is presumed that the product of the present invention is compact and lightweight as compared with the comparative product, and thus has a small heat capacity and heat dissipation, that is, heat dissipation. Further, in the porous ceramic filter of the comparative product, abnormal combustion of the collected particulates may occur, which may cause melting loss of the filter, but the product of the present invention is a felt composed of ceramic fibers. Since it is not a honeycomb-like structure, there is no region where high heat is generated during heating and burning of particulates, there is no fear of abnormal combustion, and durability is high.

Next, the exhaust gas purifying apparatus shown in FIGS.
The following is a description of the table. This exhaust gas
Scan purifier is composed of three cylindrical <br/> filter 20 disposed in the case 2, filter 20 is mounted in spaced respective end plate 26. Filter 20, a cylindrical felt 2 made of ceramic fiber
1, full Eruto 21 to shape-retaining the outer shape of the full Eruto 21
Is constructed inner shape of the wire mesh disposed over the outer surface 24及beauty off Eruto 21 from the support cylinder 23 disposed on the inner surface of the full Eruto 21 to shape-retaining. You adjacent off Eruto 2
The metal nets 24 wound up in 1 have metal rings 25 attached to their respective ends, and adjacent metal rings 25 are electrically connected to each other by a connecting wire 22. Further, electrode portions 29 are connected to the ends of the wire netting 24 of the tubular filter 20 located on both sides. Accordingly, from one electrode 29 to the other electrode portion 29, filter 20 is electrically connected in series. In this exhaust gas purifying device , in addition to the configuration in which the filter 21 is shaped by the wire mesh 24,
It is characterized by the structure of No. 4. The wire mesh 24 has a warp (or weft) made of aluminum oxide, that is, Al ₂ O ₃ , S.
It is composed of a ceramic fiber, that is, a ceramic thread 27 containing one or two kinds of i and Ti and one or more kinds of elements of C, O and N, and the weft thread (or warp thread) is a heat-resistant alloy steel. It is composed of fibers or metal wires 28.

In this exhaust gas purifying apparatus , the cylindrical filter 21 has a minor axis of 8 as a ceramic fiber which constitutes it.
φ60 × 3 by slip casting method using Si-Ti-C-O-N fiber with μm and fiber length of several cm
It is made of a tubular felt 21 of 00 mm. Also,
As wire diameter constituting the metal net 24, but can be used in the range of 50Myuemu～1mm, gold network 24, using Al ₂ O ₃ long fibers having a wire diameter of 0.34mm to weft (or warp), A heat-resistant alloy steel fiber having a similar wire diameter is used for the warp (or weft), and these are plain-woven to form a 35-mesh wire mesh. Further, the electrode connected to the metal wire 28 is composed of a Cu electrode 29. The wire net 24 was wound around each of the outer peripheral surfaces of the three cylindrical felts 21, that is, the collecting surface to form the filter 20.

Filter 2 in this exhaust gas purification device
In order to compare No. 0 with the conventional one, as a comparative product, a wire mesh of 35 mesh was constructed by using only heat-resistant alloy steel fibers, and this was wound around the tubular felt 21 to produce a filter of the comparative product . And a filter of comparative and filter 20, respectively disposed in the case 2 as shown in FIG. 9, incorporated into an exhaust gas purification system shown in FIG. 1, a durability test was carried out on the exhaust gas purification device. The durability test of the exhaust gas purifying device, and trapping particulates in the exhaust gas in the comparative filter and filter 20, the pressure loss 1
When the engine reaches 50 mmHg, the engine is stopped, the particulates collected in the filter are heated and burned to regenerate the filter, and when the regeneration of the filter is completed,
The engine was driven again, and the particulates in the exhaust gas were repeatedly collected by the filter. The results, shown in Figure 14 with respect to filter 20, also shown in Figure 15 with respect to the comparative filter.

14 and 15, the temperature measurement position in the exhaust gas purification device is each point shown in FIG.
That is, the temperature measurement position is the temperature measurement point A of the wire mesh 24 located outside the cylindrical filters 20 on both sides close to the case 2.
B, a temperature measuring point C on the inner surface of the intermediate cylindrical filter 20, a temperature measuring point D on the inner surface of the case 2, and a temperature measuring point E on the outer surface of the case 2. As can be seen from FIG. 14, for the product of the present invention, the regeneration cycle was repeated 10 times with respect to the filter, but no abnormality occurred in the exhaust gas purification device. On the other hand, in the exhaust gas purification device of the comparison product,
As can be seen from FIG. 15, with respect to the temperature measuring point B of the wire mesh, 1000 at the second regeneration cycle for the filter.
An abnormal temperature rise of over ℃ occurred, and the wire mesh was broken.
This disconnection phenomenon was caused by the knuckle portion, that is, the connecting portion, causing the wire mesh, that is, the heater, to be cut by oxidation.

Next, the exhaust gas cleaning shown in FIG. 16 and FIG.
Exhaust gas purification device
The filter 30 is arranged in the case 2, and the wire mesh filter 32 is arranged in the exhaust passage on the upstream side of the exhaust gas flow separated from the filter 30. The filter 30 has a plate-shaped felt 31 made of ceramic fibers, a metal net 34 made of a heat-resistant alloy arranged adjacent to the upstream side of the felt 31, and a holding metal net 33 adjacent to the downstream side of the felt 31. Are arranged.
The wire netting filter 32 and the wire netting 34 are connected to each other through an electrode portion 35 provided at each end, and are connected to a DC power supply 36. The felt 31 is made of Si-Ti-C-N short fibers, and the wire netting 34 and the wire netting filter 32 are formed of a heat-resistant alloy wire having a wire diameter of 0.2 mm and a filtration particle size of 69 μm. The holding wire net 33 functions to hold the short fibers of the felt 31. By energizing the wire net 34 and the wire net filter 32, the particulates collected in the filter 30 can be heated and incinerated, and the filter 30 can be regenerated.

Next, in order to test the effect of the wire mesh filter 32, one not equipped with the wire mesh filter 32, 100
those provided wire mesh filter 32 of cm ² and 160cm
Three types of exhaust gas purifying devices having the wire mesh filter 32 of No. ² were prepared. The pressure loss with respect to the elapsed time of the filter 30 of these exhaust gas purification devices is shown in FIG.
It was as shown in 7. As can be seen from FIG. 17, the pressure loss of the filter 30 increases in a short time in the case where the wire mesh filter is not provided, but the pressure loss is small in the case where the wire mesh filter 32 is provided, and the collection of particulates is prolonged. Turns out it can be done on time. That is, 16
By arranging the wire mesh filter 32 of 0 cm ² ,
It was confirmed that the rise time of pressure loss was doubled as compared with the case where the wire mesh filter was not arranged.

Next, the discharge shown in FIG. 18, FIG. 19 and FIG.
Referring to vapor gas purification apparatus, the exhaust gas purifying apparatus is mainly, as compared to the exhaust gas purifying apparatus shown in FIG. 2, the foam metal filter and control valve on the downstream side of the outlet-side exhaust passage of the exhaust gas stream Except for the difference in the configuration provided,
Since they have the same configuration, parts that perform the same function are assigned the same reference numerals and overlapping description will be omitted.

Referring to FIG. 18, in this exhaust gas purifying apparatus, a foam metal filter 40 is installed in the outlet side exhaust passage 6, and a control valve 44 which is opened and closed by an actuator 45 on the downstream side of the foam metal filter 40. Is provided. Further, in the case 2, a fiber collection box 46 for collecting the ceramic fibers scattered and exhausted to the outlet side exhaust passage 6 on the downstream side of the filter 1 is provided. A pressure sensor 41 is installed to measure the pressure in the outlet side exhaust passage 6. Further, an air conduit 42 is provided for backwashing the filter 1 and the foam metal filter 40 by sending high pressure air from a nozzle 47 installed on the downstream side of the foam metal filter 40. Air conduit 42
Is provided with a control valve 43 that opens when air is blown from the nozzle 47. The foam metal filter 40 is made of Ni
It is made of an alloy and functions as a filter that prevents the ceramic fibers constituting the filter 1 from breaking and scattering from the outlet side exhaust passage 6 to the outside.

Next, the backwash operation of this exhaust gas purification device
This will be described with reference to FIG. This exhaust gas purification device is arranged in the exhaust passage of a diesel engine with a displacement of 1700 cc, drives the diesel engine, sends the exhaust gas exhausted from the diesel engine to the exhaust gas purification device, and contains the particulates contained in the exhaust gas. Are collected by the cylindrical filter 1. When the particulate matter is collected by the tubular filter 1, the regeneration operation of the tubular filter 1 is the same as that of the exhaust gas purifying apparatus shown in FIG. 1 when the particulate matter exceeds a predetermined collection amount. , The description is omitted here. In FIG. 19, the horizontal axis shows the number of cycles (cycles) of collecting and regenerating particulates by the tubular filter 1, and the vertical axis shows the pressure (mmHg) of the outlet side exhaust passage 6 by the pressure sensor 41. )
It is shown. Referring to the graph of FIG. 19, it can be seen that the backwashing of the foam metal filter 40 causes the pressure in the outlet side exhaust passage 6 to drop significantly.

By the pressure sensor 41, the cylindrical filter 1
The pressure P downstream of is measured (step 50). It is determined whether the pressure P in the outlet side exhaust passage 6 is higher than a preset pressure P ₁ (step 51). When the pressure P becomes higher than the preset pressure P ₁ , the ceramic fiber is collected in the foam metal filter 40 and the pressure in the outlet side exhaust passage 6 is increased, so that the diesel engine is stopped or the diesel engine is stopped. Bypass the exhaust gas so that it will not be sent to the exhaust gas purification device. Therefore, the actuator 45 is operated to close the control valve 44 (step 52), and the control valve 43 is opened to blow high-pressure air from the nozzle 47 to the foam metal filter 40 (step 53). By opening the control valve 43, high-pressure air is blown from the nozzle 47 to the foam metal filter 40 through the air conduit 42, and the foam metal filter 40 is backwashed and purified. This backwash period is 0.
It is about 5 seconds. By backwashing the foam metal filter 40, the ceramic fibers collected by the foam metal filter 40 fall into the fiber collection box 46 and are collected. When the backwashing process of the foam metal filter 40 is completed and the foam metal filter 40 is regenerated, the control valve 43 is closed (step 54) and the actuator 45 is operated to clean the exhaust gas by the tubular filter 1 again. It operates to open the control valve 44 (step 55). In this exhaust gas purification device,
The backwashing operation of the foam metal filter 40 can be repeated.

Next, the exhaust gas shown in FIGS.
The purifying device is as follows. The wire mesh filter 38 is provided on the upstream side of the exhaust passage 49 in the case 2.
And a conventional wire mesh filter 39 on the downstream side,
Measure the function of the wire mesh filter. Wire mesh filter 38,3
9 has an electrode portion 48 connected to the ends thereof.
Are connected in parallel to the DC power supply 37 via a line 57. The wire mesh filter 38 incorporated in the exhaust gas purifier has a wire diameter of 41 μm and a twill twill weave 80 × 7.
A wire mesh made of SUS316 made of 00 mesh was used, and the surface of the wire was coated with aluminum Al. The wire mesh filter 39 has a wire diameter of 41 μm,
SUS31 composed of Tatami Twill 80 × 700 mesh
6 Wire mesh made of aluminum A on the surface of the wire
1 is not coated.

This exhaust gas purifying apparatus is operated in the atmosphere at 100
The oxidation state of the wire mesh filters 38, 39 was measured by performing an oxidation test for 20 hours at 0 ° C. The result is shown in FIG.
Shown in. The wire mesh filter 38 coated with Al is
The increase in oxidized weight was 4%, and the elastic properties of the wire mesh filter 38 were retained. On the other hand, in the wire mesh filter 39 not coated with Al, the increase in the oxidized weight is 39%, and the entire wire mesh filter 38 is in the oxidized state, and the elastic characteristics as well as the metal characteristics are exhibited. Was lost. Therefore, by coating the surface of the wire of the wire mesh filter with aluminum, oxidation of the wire mesh itself is suppressed, and the wire mesh made of SUS316 is effective even under the condition of 1000 ° C. which is expected when the wire mesh filter is heated and regenerated. Do you get it.

Next, the exhaust gas purifying apparatus shown in FIG.
The explanation is as follows. As the exhaust gas purifying device, the one shown in FIG. 21 was used. Similarly, one wire mesh filter incorporated in the exhaust gas purifying apparatus was made of SUS430 wire mesh having a wire diameter of 41 μm and a twill twill weave of 80 × 700 mesh, and the surface of the wire material was made of alumina Al ₂ O. ₃ coated. The other wire mesh filter has a wire diameter of 41 μm and a twill twill weave of 80 × 70.
Made with SUS430 wire mesh configured to 0 mesh,
The surface of the wire is not coated with alumina.

This exhaust gas purifying apparatus is operated in the atmosphere at 100
The oxidation state of both wire netting filters was measured by performing an oxidation test for 20 hours at 0 ° C. The result is shown in FIG. The alumina-coated wire mesh filter had an increase in the oxidized weight of 4%, and retained the elastic properties of the wire mesh filter and the insulating property of the filter surface. On the contrary,
In the wire mesh filter not coated with alumina, the increase in the oxidized weight was 42%, the entire wire mesh filter was in an oxidized state, and the elastic property as well as the metal property was lost. In order to prevent this phenomenon, the surface of the wire of the wire mesh filter is coated with alumina to suppress the oxidation of the wire mesh itself, and even under the condition of 1000 ° C. which is expected when the wire mesh filter is heated and regenerated.
The S430 wire mesh has been found to be effective.

[0038] In particular, FIG. 24, with reference to FIGS. 25 and 26, illustrating the real施例exhaust gas purification apparatus according to the present invention. 24 is a cross-sectional view showing an embodiment of an exhaust gas purifying apparatus according to the present invention, FIG. 25 is a perspective view showing a main part of the exhaust gas purifying apparatus of FIG. 24, and FIG. 26 is a filter of the exhaust gas purifying apparatus of FIG. It is an expanded sectional view showing an important section.

This exhaust gas purification device can be used by incorporating it into the exhaust gas purification system shown in FIG.
It has the same structure except that the structure of the filter is different from the cylindrical filter 1 of FIG. In this exhaust gas purification device, a filter 60 is incorporated in a case 2 with a heat insulating material 62 interposed. The filter 60 includes a felt 61 made of ceramic fiber and a felt 61.
It is composed of a wire mesh 64 that retains the outer shape of the. The end of the felt 61 is sealed with a first metal plate 68, and the first metal plate 68 and the wire mesh 64 are welded at a position of reference numeral 65. Further, the felt 61 is sequentially folded back in a U-shape from the upstream side exhaust passage 5 of the exhaust gas flow to the downstream side exhaust passage 6, and the second metal plate 67 that seals both ends of the folded back felt 61 is In order to maintain the shape of the folded-back felt 61, it is welded to the first metal plate 68 at the position of reference numeral 66.

The first metal plate 68 and the second metal plate 67 are made of metal or Ni plate made of the same material as the wire mesh. In addition, the first metal plate 68, the second metal plate 67 and the wire mesh 64 are
The second metal plate 67 can be electrically connected in series, and then the second metal plate 67 can function as an electrode unit. The heat insulating material 62 is made of an inorganic material having a high density. In addition, wire mesh 6
The connection between 4 and the first metal plate 68 can be welded using seam welding or a brazing material. Second with the first metal plate 68
The connection with the metal plate 67 can be made by spot welding. The second metal plate 67 can also function as a closing plate that prevents the exhaust gas from leaking from the filter 60.

[0041]

Since the exhaust gas purifying apparatus according to the present invention is constructed as described above, when a predetermined amount of particulates is collected by the filter, the wire mesh is energized to heat the filter, The curate is heated and incinerated to regenerate the filter . Since previous SL filter is shape retention of a ceramic fiber into a cylindrical shape with a wire mesh of short fibers, by passing through the filter exhaust gas, particulates in exhaust gases between the fibers and the fibers are entangled It is collected uniformly and surely. Further, a wire mesh, a metal wire, or a metal plate may be arranged inside the felt made of the ceramic fiber.

Moreover, in this exhaust gas purifying apparatus, since the felt made of ceramic fibers is retained by the wire mesh capable of conducting electricity, the scattering of the fibers of the felt itself can be reduced, and the felt has a predetermined shape for a long period of time. And the durability of the filter can be improved.
When the wire mesh covering the felt is energized through the electrode portion, the entire surface of the felt is uniformly heated, and the filter can be uniformly heated in the entire area and can be heated in a short time. The particulates are immediately heated and incinerated, and the filter is regenerated in a short time. Moreover, when the particulates are incinerated, the particulates burn uniformly in the filter and the particulates do not locally remain in the filter in an unburned state, and abnormal combustion occurs and local heating occurs. Does not occur, abnormal heat stress is not applied to the filter, and it is possible to prevent the filter from being deformed or melted.
Therefore, this exhaust gas purifier is installed in the exhaust pipe of a diesel engine, and the carbon contained in the exhaust gas,
It is possible to achieve exhaust gas purification that is extremely effective in collecting particulates such as soot and smoke.

The exhaust gas purifying device according to the invention, the
In particular, the end of the felt is sealed with a first metal plate, the first metal plate and the wire mesh are welded, and the felt is further connected from the upstream side to the downstream side of the exhaust gas flow. and wherein the sequential folding, to the second metal plate that seals both ends of the felt folded constructed by welding the first metal plate for maintaining the shape of the felt to
I am doing .

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an exhaust gas purification system in which an exhaust gas purification device according to the present invention can be incorporated.

2 is a sectional view showing the exhaust gas purifying equipment for this.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a cross-sectional view showing an exhaust gas purification device of a comparative product.

5 is a cross-sectional view taken along the line BB in FIG.

[6] The exhaust gas purifying apparatus and comparative exhaust gas purifying apparatus of this is a graph showing the collection efficiency with respect to the elapsed time.

[7] The exhaust gas purifying apparatus and comparative exhaust gas purifying apparatus of this is a graph showing the pressure loss with respect to the elapsed time.

[8] The exhaust gas purifying apparatus and comparative exhaust gas purifying apparatus of this is a graph showing the temperature of the filter center with respect to the elapsed time.

9 is a sectional view showing the exhaust gas purifying equipment for this.

10 is a cross-sectional view taken along the line CC of FIG.

FIG. 11 is a perspective view of the filter of the exhaust gas purification apparatus of FIG. 9 with a part thereof cut away.

FIG. 12 is a plan view showing a metal net in the exhaust gas purification device of FIG. 9.

13 is a cross-sectional view showing a wire mesh in the exhaust gas purification device of FIG.

14 is a graph showing a temperature in each region with respect to the elapsed time of the exhaust gas purifying apparatus of this.

FIG. 15 is a graph showing the temperature in each region with respect to the elapsed time of the exhaust gas purifying apparatus of the comparative product.

16 is a sectional view showing the exhaust gas purifying equipment for this.

FIG. 17 is a graph showing pressure loss over time for a filter.

18 is a sectional view showing the exhaust gas purifying equipment for this.

FIG. 19 is a graph showing pressure drop versus regeneration cycle for a filter.

FIG. 20 is a process flow chart showing an embodiment of the operation of the exhaust gas purification device.

21 is a cross-sectional view showing the exhaust gas purifying equipment for this.

FIG. 22 is a graph showing a change in oxidized weight between a wire mesh coated with aluminum and an uncoated wire mesh.

FIG. 23 is a graph showing changes in oxidized weight of a wire mesh coated with alumina and an uncoated wire mesh.

24 is a cross-sectional view showing the actual施例exhaust gas purification apparatus according to the present invention.

FIG. 25 is a perspective view showing a main part of the exhaust gas purification device of FIG. 24.

FIG. 26 is an enlarged cross-sectional view showing the main parts of a filter incorporated in the exhaust gas purification device of FIG. 24.

[Explanation of symbols]

20, 30, 60 filters 2 cases 4,64 wire mesh 5 Inlet side exhaust passage 6 Exit side exhaust passage 7,29,35,48 Electrode part 8,31,61 felt 27 Ceramic yarn (warp yarn) 28 Metal wire (weft) 36,37 power supply 40 foam metal filter 67 Second metal plate 68 First metal plate 90 diesel engine

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takamoto Suzuki 8 Tsutana, Fujisawa City, Kanagawa Prefecture Isuzu Ceramics Laboratory Co., Ltd. (56) References JP 63-197511 (JP, A) JP 62 -114621 (JP, A) JP 63-65114 (JP, A) JP 6-17638 (JP, A) JP 5-245317 (JP, A) JP 58-174240 (JP, A) ) Actual development Sho 56-171617 (JP, U) Actual development Hei 5-27221 (JP, U) Actual development Sho 50-111776 (JP, U) International publication 93/020919 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F01N 3/02

Claims (2)

(57) [Claims] 1. A exhaust gas purifying apparatus for heating incinerated by collecting particulates contained in the exhaust gas is disposed in an exhaust system of a diesel engine, disposed within said integrated into an exhaust system casing and the filter for collecting the particulate matter contained in <br/> exhaust gas is constituted by energizable wire mesh that holds sandwiching the felt and the felt composed of short fibers of ceramic fiber, the filter is of the exhaust gas Flow direction
Are sequentially folded back in parallel to the both ends of the filter.
Is welded and sealed to the wire mesh by the first metal plate.
The second metal plate covering the first metal plate is
Is welded to the first metal plate to maintain its shape ,
An exhaust gas purifying apparatus, characterized in that by energizing the wire mesh to heat the filter, the particulate matter collected in the filter is incinerated by heating to regenerate the filter. 2. The first metal plate and the second metal plate,
It is composed of a metal or a Ni plate of the same material as the wire net, and the first metal plate, the second metal plate and the wire net are electrically connected to each other so that the second metal plate can be used as an electrode. The exhaust gas purifying apparatus according to claim 1 .