JP4255205B2 - Exhaust gas purification device and holding seal body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas purification device that removes particulates and the like in exhaust gas discharged from an internal combustion engine such as a diesel engine, and the exhaust gas purification deviceHolding seal body used forAbout.
[0002]
[Prior art]
Recently, it has been a problem that particulates contained in exhaust gas discharged from internal combustion engines such as vehicles such as buses and trucks and construction machines cause harm to the environment and the human body.
Various ceramic filters that can purify the exhaust gas by passing the exhaust gas through a porous ceramic and collecting particulates in the exhaust gas have been proposed.
[0003]
The honeycomb filter usually has a configuration in which a plurality of porous ceramic sintered bodies 30 made of silicon carbide or the like are bundled like the honeycomb filter 12 shown in FIG. 2, and a holding seal body 13 is formed around the sintered body. ing. Further, as shown in FIG. 3, the porous ceramic sintered body 30 has a large number of through holes 31 arranged in parallel in the longitudinal direction, and the partition wall 33 separating the through holes 31 functions as a filter. Yes.
[0004]
That is, in the through-hole 31 formed in the porous ceramic sintered body 30, either the inlet side or the outlet side end of the exhaust gas is plugged with the filler 32 as shown in FIG. The exhaust gas flowing into one through hole 31 always flows through the partition wall 33 separating the through holes 31 and then flows out from the other through holes 31.
[0005]
In the exhaust gas purification device, the honeycomb filter 12 having such a configuration is installed in the exhaust passage of the internal combustion engine, and particulates in the exhaust gas discharged from the internal combustion engine are separated by the partition wall 33 when passing through the honeycomb filter 12. It is captured and the exhaust gas is purified.
[0006]
FIG. 1 is a cross-sectional view schematically showing an example of an exhaust gas purification device.
In this exhaust gas purification device 10, an introduction pipe 16 into which exhaust gas discharged from an internal combustion engine is introduced is connected to one end portion of the casing 11, and exhaust gas that has passed through the honeycomb filter 12 is connected to the other end portion. A discharge pipe 17 for discharging to the outside is provided. A honeycomb filter 12 is installed inside the casing 11 via a holding seal body 13.
Further, an electric heater 14 for burning particulates accumulated in the honeycomb filter 12 is installed in a portion on the exhaust gas introduction side with respect to the honeycomb filter 12, and the temperature sensor 15 is in contact with the honeycomb filter 12. A pipe 18 is connected to feed air or the like when combustion is performed.
[0007]
The exhaust gas enters the inside of the casing 11 from the introduction pipe 16 and passes through the honeycomb filter 12, whereby particulates are captured by the partition walls 33 and are discharged from the discharge pipe 17. When the accumulated amount of particulates increases and the pressure loss of the honeycomb filter 12 increases, regeneration processing is performed.
[0008]
In the exhaust gas purification device 10, the honeycomb filter 12 is installed in the casing 11 via the holding seal body 13. The holding seal body 13 is provided for the purpose of heat insulation or the like, but the holding seal body 13 conventionally used is mainly made of ceramic fiber, and its thermal conductivity at high temperature. Was not so low, and the heat insulation performance was not sufficient.
[0009]
Therefore, it is easily affected by the outside air temperature in a cold region, etc., and the temperature rise of the honeycomb filter 12 is hindered, and it takes a long time to regenerate. In addition, the temperature of the peripheral portion was lowered during regeneration, and unburned particulates were likely to remain in the peripheral portion, resulting in a large increase in pressure loss. As a result, the time until regeneration was required was short.
[0010]
In addition, since the temperature difference between the internal temperature (600 ° C.) and the external temperature is large, in the conventional apparatus in which the heat insulating performance of the holding seal body 13 is not sufficient, it is generated between the vicinity of the central portion and the peripheral portion of the honeycomb filter 12. Thermal stress is generated due to the temperature difference, and the honeycomb filter 12 is liable to crack, resulting in poor durability.
[0011]
[Problems to be solved by the invention]
The present invention has been made to solve these problems, and can be efficiently regenerated in a short time even in applications (vehicles) with limited electric capacity, and local combustion during particulate regeneration. As well as preventing the remaining residue, the temperature of the peripheral portion of the honeycomb filter does not decrease during the exhaust gas treatment, and therefore, an exhaust gas purification device with excellent durability that can prevent the occurrence of cracks due to thermal stress, andHolding seal body used in the exhaust gas purification deviceIs intended to provide.
[0012]
[Means for Solving the Problems]
The exhaust gas purifying apparatus of the present invention is an exhaust gas purifying device comprising a porous ceramic sintered body in which a large number of through holes are arranged in the longitudinal direction and the partition walls separating the through holes function as a filter. An exhaust gas purification apparatus in which a honeycomb filter is installed in a casing connected to an exhaust passage of an internal combustion engine, and a holding seal body is interposed between the honeycomb filter and the casing,
The holding seal bodyIncludes alumina fibers, titania particles and silica gel, and the holding sealing body.The thermal conductivity at 800 ° C. is 0.1 W / m · K or less.
[0013]
In addition, the present inventionHolding seal bodyIsAn exhaust gas purifying honeycomb filter comprising a porous ceramic sintered body having a large number of through holes arranged in parallel in the longitudinal direction and a partition wall separating the through holes functioning as a filter is an exhaust passage of an internal combustion engine. The holding seal body used in an exhaust gas purification apparatus installed in a casing connected to the honeycomb filter and a holding seal body interposed between the honeycomb filter and the casing,
It contains alumina fibers, titania particles and silica gel, and the thermal conductivity at 800 ° C. is 0.1 W / m · K or less.It is characterized by this.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an exhaust gas purification device of the present invention and a method of manufacturing the exhaust gas purification device of the present invention will be described with reference to the drawings.
[0015]
First, the exhaust gas purification apparatus of the present invention will be described.
The structure of the exhaust gas purifying apparatus of the present invention is substantially the same as that of the conventional exhaust gas purifying apparatus described above, and will be described with reference to FIGS.
[0016]
The exhaust gas purifying apparatus of the present invention is an exhaust gas purifying device comprising a porous ceramic sintered body in which a large number of through holes are arranged in the longitudinal direction and the partition walls separating the through holes function as a filter. A honeycomb filter is installed in a casing connected to an exhaust passage of an internal combustion engine, and an exhaust gas purifying device in which a holding seal body is interposed between the honeycomb filter and the casing, wherein the holding seal body The thermal conductivity at 800 ° C. is 0.1 W / m · K or less.
[0017]
Regarding the structure of the porous ceramic sintered body, the honeycomb filter, and the exhaust gas purifying device, the porous ceramic sintered body 30, the honeycomb filter 12, and the exhaust gas purifying described in the above-described conventional technology with reference to FIGS. Since it is substantially the same as the apparatus 10, the description is abbreviate | omitted here.
Other specific contents of these members will be described later.
[0018]
The holding seal body has a thermal conductivity at 800 ° C. of 0.1 W / m · K or less. If it exceeds 0.1 W / m · K, heat transferred to the honeycomb filter 12 or the like in the regeneration process or the like is easily released from the outer peripheral portion to the outside of the casing 11 through the holding seal body, and the periphery of the honeycomb filter 12 The temperature of the portion decreases, and the entire honeycomb filter 12 cannot be heated to a uniform temperature.
[0019]
Here, the thermal conductivity at 800 ° C. is that when the honeycomb filter 12 is regenerated, the temperature of the honeycomb filter 12 may rise to nearly 800 ° C. If the thermal conductivity at 800 ° C. is 0.1 W / m · K because the conductivity is lowered, the thermal conductivity is further lowered at a lower temperature than that, and the heat retention is more excellent. .
[0020]
The holding seal body is wound around the side surface of the honeycomb filter 12, and the thickness thereof is a space formed by the honeycomb filter 12 and the inner wall of the casing 11 when the honeycomb filter 12 is installed in the casing 11. Prepared to be completely occluded. Specifically, it is preferably 2.0 to 8.0 mm. If the thickness of the holding seal body is less than 2.0 mm, the thickness is too thin. Even if the thermal conductivity of the holding seal body itself is low and the heat insulation performance is excellent, the heat conduction at high temperatures is affected by radiant heat. As a result, the thermal conductivity becomes high and the soaking property of the honeycomb filter 12 cannot be ensured. On the other hand, even if the thickness of the holding seal body exceeds 8.0 mm, the heat insulation property of the holding seal body is no longer improved and the economy is inferior.
[0021]
Examples of the holding sealing body having such a thermal conductivity include alumina fibers. This alumina fiber is particularly excellent in high temperature resistance and high heat characteristics.
Examples of the material of the holding sealing body other than the alumina fibers include high-temperature heat insulating materials such as ceramic fibers and rock wool. Naturally, such high-temperature heat insulating materials also satisfy the thermal conductivity conditions. There is a need to. Usually, an alumina fiber excellent in heat retaining performance is preferable.
[0022]
The alumina fibers are preferably prepared by mixing alumina fibers together with silica gel, titania particles and the like, and then molding. The silica gel suppresses air convection, thereby realizing a decrease in thermal conductivity, and the titania particles reflect radiant heat, thereby preventing an increase in thermal conductivity due to the influence of radiant heat.
[0023]
Moreover, the bulk density of the alumina fibers is 0.20 to 0.50 g / cm in a state wound around the honeycomb filter 12.^Three It is preferable that Bulk density is 0.2g / cm^Three If it is less than 1, in general, the heat insulation performance is excellent, but heat conduction at high temperatures is strongly affected by radiant heat, and as a result, the heat conductivity becomes high, and the heat conductivity at 800 ° C. is 0.1 W. / M · K or less. On the other hand, the bulk density is 0.50 g / cm.^Three In the case of exceeding the thermal conductivity, the thermal conductivity does not increase due to the influence of the radiant heat due to the high temperature, but conversely, the thermal conductivity increases due to the bulk density being too large, and the thermal conductivity at 800 ° C. is 0.1 W / m.・ It becomes difficult to make K or less.
[0024]
The alumina fiber preferably has a thermal expansion coefficient of about 5 to 70% at 350 to 700 ° C. When the holding seal body (alumina fiber) has such a thermal expansion coefficient, when actually used as an exhaust gas purification device, the holding seal body is heated and expanded, and the honeycomb filter 12 and the casing 11 can be completely closed.
[0025]
Moreover, since the holding sealing body using the alumina fiber is excellent in form stability, it is not easily deformed or altered by the high-temperature exhaust gas blown continuously. That is, it has excellent wind erosion resistance.
[0026]
The honeycomb filter 12 is configured by binding a plurality of porous ceramic sintered bodies 30 as shown in FIG. Further, the shape is not particularly limited, and may be a cylindrical shape or a prismatic shape, but usually a cylindrical shape is often used as shown in FIG.
[0027]
The material of the porous ceramic sintered body 30 is not particularly limited, and examples thereof include various ceramics. Among these, silicon carbide having high heat resistance, excellent mechanical characteristics, and high thermal conductivity. Is preferred.
[0028]
The particle size of these ceramics is not particularly limited, but those having less shrinkage in the subsequent firing step are preferred. For example, 100 parts by weight of powder having an average particle size of about 0.3 to 50 μm and 0.1 parts by weight A combination of 5 to 65 parts by weight of powder having an average particle diameter of about 1.0 μm is preferable.
[0029]
The material of the casing 11 is not particularly limited, and examples thereof include stainless steel.
Further, the shape is not particularly limited, and may be a cylindrical shape as shown in FIG. 5A, or a two-divided shell shape in which the cylindrical shape as shown in FIG. 5B is divided into two in the axial direction. It may be.
[0030]
The size of the casing 11 is appropriately adjusted so that the honeycomb filter 12 can be installed inside. And although not shown in figure, the introduction pipe | tube which flows in exhaust gas is connected to the one end surface of this casing, and the exhaust pipe which discharges | emits exhaust gas is connected to the other end surface. In addition, although there may exist piping which flows in the air shown in FIG. 1, since other methods can also be taken, it is not an essential member.
[0031]
Although not shown, a honeycomb filter 12 is installed inside the casing, and a temperature sensor or an electric heater may be installed on the introduction pipe side of the honeycomb filter 12 as necessary. Wiring may be provided so that a temperature sensor, an electric heater, or the like can be connected to an external power source or the like.
[0032]
The exhaust gas purifying apparatus of the present invention is configured as described above, and the holding seal body interposed between the honeycomb filter and the casing has excellent wind erosion resistance, and because of its excellent heat insulation properties, The temperature of the honeycomb filter is hardly changed even when the ground is not affected by the outside air temperature, and even when the water splashes during running, etc., and the honeycomb filter can be kept stable at a high temperature. Breakage can be prevented. In other words, by interposing the holding seal body having such characteristics, the exhaust gas purifying apparatus is excellent in durability and hardly causes pressure loss.
[0033]
Also in the regeneration process, the heat efficiency is good, the regeneration time can be shortened, the regeneration rate is improved, and the time until pressure loss or the like increases (the time until regeneration is necessary) can be extended. That is, the amount of particulate collection after regeneration increases.
[0034]
When the exhaust gas purification apparatus of the present invention includes the electric heater for burning particulates as described above, the temperature of the exhaust gas entering the honeycomb filter can be increased efficiently and in a short time. In addition, the temperature of the exhaust gas can be made sufficiently high, so that the regeneration process can be performed in a short time.
[0035]
Moreover, the exhaust gas purification apparatus of the present invention may not include an electric heater. In this case, it is possible to perform a regeneration operation in which the temperature of the exhaust gas is increased.
Since the exhaust gas purifying apparatus of the present invention is excellent in the heat retention of the honeycomb filter, the temperature of the exhaust gas passing through the honeycomb filter can be sufficiently increased even when the above regeneration treatment method is adopted, and the temperature is increased. With the exhaust gas, the particulates can be burned and regenerated.
[0036]
The exhaust gas purifying device of the present invention includes a back pressure sensor for measuring the pressure loss of the honeycomb filter and displays that it is necessary to perform a regeneration process when the back pressure rises above a predetermined value. You may provide the device etc. which do.
[0037]
Further, when the exhaust gas purification device of the present invention is disposed in a vehicle, two or more exhaust gas purification devices of the present invention may be provided in parallel. In this case, two exhaust gas purification devices are connected to the exhaust gas pipe, and one of them is used by using a switching valve or the like, and the other one is regenerated between them.
[0038]
Furthermore, a catalyst layer for removing harmful gases such as Nox and Sox may be provided in the exhaust gas purifying apparatus of the present invention so that both harmful gas removal and particulate removal can be performed. .
In the present invention, the exhaust gas can be used as an auxiliary combustion gas during regeneration. In addition, when the regeneration process is performed using a pump, the regeneration process can be performed by sending air into the filter using the pump.
[0039]
Next, the manufacturing method of the exhaust gas purification apparatus of this invention is demonstrated.
The method for producing an exhaust gas purification apparatus of the present invention is an exhaust gas comprising a porous ceramic sintered body in which a large number of through holes are arranged in the longitudinal direction and the partition walls separating the through holes function as a filter. After the holding seal body of the exhaust gas purification apparatus of the present invention is wound around the side surface of the purification honeycomb filter, the honeycomb filter around which the holding seal body is wound is connected to the exhaust passage of the internal combustion engine. A method of manufacturing an exhaust gas purifying device installed in a casing, wherein a convex portion is formed at one end of the holding seal body, and a shape that can be fitted to the convex portion at the other end of the holding seal body. A concave portion is formed, and the holding seal body is wound around the honeycomb filter.
[0040]
In the method for manufacturing an exhaust gas purification apparatus of the present invention, first, a porous ceramic sintered body and a honeycomb filter are manufactured.
First, after preparing a mixed composition containing the above-described ceramic particles such as silicon carbide, a binder, and a dispersion medium liquid, a large number of through holes are separated from each other by partitioning the partition walls by an extrusion method or the like using this mixed composition. Columnar ceramic molded bodies arranged in parallel in the direction are produced.
[0041]
The binder is not particularly limited, and examples thereof include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, phenol resin, and epoxy resin.
Usually, the amount of the binder is preferably about 1 to 10 parts by weight with respect to 100 parts by weight of the ceramic powder.
[0042]
The dispersion medium liquid is not particularly limited, and examples thereof include organic solvents such as benzene; alcohols such as methanol, and water.
An appropriate amount of the dispersion medium liquid is blended so that the viscosity of the mixed composition falls within a certain range.
[0043]
These ceramic powder, binder, dispersion medium and the like are mixed with an attritor or the like and then sufficiently kneaded with a kneader or the like.
[0044]
Next, the ceramic molded body is dried, a predetermined portion of the through hole is filled with a filler, and heated to 400 to 650 ° C. in an oxygen-containing atmosphere to volatilize the binder and the like, and decompose and disappear. Then, a degreasing process in which only ceramic powder remains is performed.
[0045]
Thereafter, in an inert gas atmosphere such as nitrogen or argon, for example, for a silicon carbide molded body, a sintering step is performed in which ceramic powder is sintered by heating to 2000 to 2200 ° C., and porous ceramic sintering Manufacture the body.
[0046]
A plurality of the porous ceramic sintered bodies produced above are bound together through an adhesive layer to produce a ceramic block of a predetermined size, and after drying, the outer peripheral portion thereof is cut into a predetermined shape with a diamond cutter, for example. Thus, a honeycomb filter is manufactured.
[0047]
Next, a step of winding the holding seal body around the side surface of the manufactured honeycomb filter is performed.
[0048]
The material of the holding seal body used in the method for manufacturing the exhaust gas purification apparatus of the present invention is the same as that of the holding seal body described in the exhaust gas purification apparatus of the present invention. That is, the thermal conductivity of this holding seal body at 800 ° C. is 0.1 W / m · K or less.
[0049]
FIG. 4A is a plan view schematically showing an example of the holding sealing body, and FIG. 4B schematically shows a state in which the holding sealing body shown in FIG. FIG.
[0050]
As shown in FIG. 4, a convex portion 42 is formed at one end of the holding seal body 41, and the other end portion is fitted with the convex portion 42 when the holding seal body 41 is wound around the honeycomb filter. A recess 43 having a possible shape is formed.
[0051]
The holding seal body 41 is formed in such a shape, and when the holding seal body 41 is wound around the honeycomb filter, the holding seal body 41 is accurately wound around the outer peripheral portion of the honeycomb filter by fitting the convex portion 42 into the concave portion 43. Can be done easily and can be wound in a short time.
Further, when the holding seal body 41 is wound around the outer peripheral portion of the honeycomb filter, the end portion having the convex portion 42 and the end portion having the concave portion 43 are fitted so that the convex portion 42 and the concave portion 43 are firmly engaged with each other. Does not shift from side to side and is excellent in form stability.
[0052]
Since the conventional holding seal body 13 has a substantially rectangular shape, a linear gap may be formed at both ends of the holding seal body 13 when wound around the honeycomb filter. Thus, if there is a linear gap in the holding seal body, the exhaust gas flows through this gap, and the exhaust gas cannot be completely purified.
[0053]
However, since the holding seal body used in the method for manufacturing the exhaust gas purification apparatus of the present invention is wound around the honeycomb filter in a state in which the convex portions 42 and the concave portions 43 are fitted, there is no gap in the portion other than the convex portions 42. Even if this occurs, there is no gap in the portion where the convex portion 42 and the concave portion 43 are fitted.
Accordingly, the exhaust gas flowing into the gap is blocked by the fitting portion and does not escape as it is, and the entire exhaust gas passes through the honeycomb filter and is purified.
[0054]
The size of the convex portion 42 is appropriately adjusted according to the size of the honeycomb filter or the holding sealing body 41. For example, the vertical width l is preferably about 40 to 70 mm, and the horizontal width m is preferably about 20 to 40 mm. Further, the size of the concave portion 43 is adjusted to be the same size as the convex portion 42 or slightly larger.
[0055]
Moreover, although the shape of the convex part 42 and the recessed part 43 is substantially rectangular, the shape is not limited to these, For example, a triangle and a semicircle shape may be sufficient. Also, the number is not particularly limited to one and may be two or more.
[0056]
The means for winding and fixing the holding seal body 41 around the honeycomb filter is not particularly limited, and examples thereof include means for attaching with an adhesive or binding with a string-like body. In addition, the process may be shifted to the next step without being fixed by special means and only being wound around the honeycomb filter. The string-like body may be a material that decomposes by heat. This is because, after the honeycomb filter is installed in the casing, even if the string-like body is decomposed by heat, since the honeycomb filter is installed in the casing, the holding seal body 41 is not peeled off. .
[0057]
Next, the honeycomb filter that has undergone the above steps is installed in a casing.
Note that the material, shape, configuration, and the like of the casing are as described above, and thus the description thereof is omitted here.
[0058]
As a method of installing the honeycomb filter in the casing, when the casing is a cylindrical casing 21 (FIG. 5 (a)), for example, the honeycomb filter around which the holding seal body is wound is formed from one end surface thereof. An example is a method of forming end faces for connecting to an introduction pipe, a pipe, a discharge pipe, and the like at both ends of the casing 21 after being pushed in and installed at a predetermined position. The casing 21 may be a bottomed cylinder.
At this time, the thickness of the holding seal body, the size of the honeycomb filter, the size of the casing, etc., to the extent that it can be finally pushed in with a considerable force applied so that the fixed honeycomb filter does not move easily. Need to be adjusted.
[0059]
Further, as shown in FIG. 5B, when the casing is a two-divided shell-shaped casing 22, for example, the honeycomb filter is installed at a predetermined position in the semi-cylindrical lower shell 22b. After that, the semi-cylindrical upper shell 22a is placed on the lower shell 22b so that the through hole 23a formed in the upper fixing portion 23 and the through hole 24a formed in the lower fixing portion 24 overlap each other. And the upper shell 22a and the lower shell 22b are fixed by inserting the volt | bolt 25 in the through-holes 23a and 24a and fixing with a nut etc. And the method of forming the end surface which has an opening for connecting with an introductory pipe, piping, a discharge pipe, etc. in the both ends of the casing 22 can be mentioned. Also in this case, it is necessary to adjust the thickness of the holding seal body, the size of the honeycomb filter, the size of the casing, and the like so that the fixed honeycomb filter does not move.
[0060]
This two-part shell-like casing 22 is easier to replace the honeycomb filter installed inside than the cylindrical casing 21.
[0061]
Thereafter, the casing having the honeycomb filter installed therein is connected to the exhaust passage of the internal combustion engine, thereby completing the manufacture of the exhaust gas purifying apparatus of the present invention.
[0062]
By performing the method for manufacturing the exhaust gas purification apparatus of the present invention described above, it is possible to easily and reliably wind the holding seal body excellent in heat insulation around the outer peripheral portion of the side surface of the honeycomb filter.
[0063]
In addition, the holding seal body does not shift from side to side during use of the exhaust gas purification device, and an exhaust gas purification device having excellent form stability can be manufactured, and a gap exists between the end portions of the holding seal body. Even if it does, exhaust gas does not distribute | circulate through this clearance gap, but the exhaust gas purification apparatus which can purify exhaust gas favorably can be manufactured.
[0064]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0065]
Example 1
After kneading by adding an organic binder, water, and the like to the silicon carbide powder, extrusion molding is performed to produce a honeycomb-shaped formed body, followed by drying, degreasing, and firing to obtain an average as shown in FIG. The pore diameter is 5 to 20 μm, and the number of cells is 31 / cm.² Thus, a porous ceramic member 30 made of a silicon carbide sintered body having a partition wall thickness of 0.3 mm was produced.
[0066]
Next, the porous ceramic member 30 is bundled in large numbers using a heat-resistant adhesive containing inorganic fibers such as ceramic fibers or inorganic particles such as silicon carbide, and then cut using a diamond cutter. Thus, a honeycomb filter 12 having a diameter of 165 mm and a length of 150 mm as shown in FIG. 2 was produced.
[0067]
Then, a holding seal body was wound around the outer peripheral portion of the side surface of the honeycomb filter 12. The holding sealing body is made of alumina fibers (alumina 80 wt%, silica 20 wt%), the thermal conductivity at 800 ° C. is 0.09 W / m · K, the thermal expansion coefficient at 800 ° C. is 60%, and the bulk density is 0.00. 35 g / cm^Three The thickness was 8.5 mm. Further, the shape of the holding seal body is as shown in FIG. 4A, the vertical width of the convex portion is 50 mm, the horizontal width is 30 mm, and the size of the concave portion is the same as that of the convex portion. In addition, the winding to the honeycomb filter 12 was made to fit the said convex part and the said recessed part.
[0068]
The honeycomb filter 12 around which the holding seal body is wound by the above method is installed in a two-shell shell casing as shown in FIG. 5B, and exhaust gas purification as shown in FIG. 1 is performed using this casing. The device was made and attached to a forklift. The exhaust gas purification device was provided with a temperature sensor and a back pressure sensor.
Next, when this forklift was in an unloaded state, the engine was operated at the maximum rotation speed for 8 hours, and the back pressure was measured by a back pressure sensor, it showed a value of 40 kPa. At this time, 65 g of particulate was deposited on the honeycomb filter 12.
[0069]
Therefore, by energizing the electric heater, driving the air pump, and performing the regeneration process, the particulates are burned, and the particulates such as soot can be burned 100% completely in 40 minutes. The back pressure also returned to the initial value of 5 kPa. The temperature of the honeycomb filter 12 during regeneration was measured by a temperature sensor and found to be about 800 ° C.
Further, when the honeycomb filter 12 was inspected, no cracks or breakage were observed.
[0070]
In addition, as a wind erosion test, a plate-like body (10 cm × 10 cm × 10 cm) made of the same component as the above holding seal body was prepared, and air heated to 700 ° C. was sprayed with a wind pressure of 0.3 MPa, and the erosion distance was It was 12 mm when measured.
[0071]
Comparative Example 1
A honeycomb filter was manufactured in the same manner as in Example 1. Next, an exhaust gas purification device was prepared in the same manner as in Example 1 except that a holding seal body made of ceramic fibers (alumina 50 wt%, silica 50 wt% added with vermiculite powder) was formed on the outer periphery of the manufactured honeycomb filter. Manufactured. This holding sealing body has a thermal conductivity of 0.16 W / m · K, a thermal expansion coefficient at 800 ° C. of 60%, and a bulk density of 0.8 g / cm.^Three The thickness was 5.7 mm.
The exhaust gas purification device was attached to a forklift, and a metering pump or the like was attached to provide a regeneration system for the forklift.
[0072]
Next, when this forklift was in an unloaded state, the engine was operated at the maximum rotation speed for 8 hours, and the back pressure was measured by a back pressure sensor, it showed a value of 40 kPa. At this time, 65 g of particulate was deposited on the honeycomb filter.
[0073]
Therefore, a voltage is applied to the electric heater, the temperature of the electric heater is set to 800 ° C., and air is allowed to flow for 45 minutes at a flow rate of 40 liters / minute using a metering pump to burn particulates such as soot. However, there was a slight residue and the burning rate of the particulates was 90%.
After this step, when the honeycomb filter according to Comparative Example 1 was inspected, slight cracks were observed near the outer periphery thereof.
[0074]
Moreover, when the plate-like body of the holding seal body according to the present comparative example 1 was produced in the same manner as in Example 1, and the erosion test was performed under the same conditions as in Example 1, the erosion distance was 80 mm.
[0075]
【The invention's effect】
Since the exhaust gas purifying apparatus of the present invention is as described above, the holding seal body is excellent in wind erosion resistance, the regeneration time of the honeycomb filter can be shortened, and the regeneration rate can be increased. Further, it is possible to prevent a decrease in the temperature of the honeycomb filter at the time of exhaust gas treatment, and to prevent a residue from burning of particulates at the time of regeneration from remaining locally in a part of the honeycomb filter and to prevent generation of cracks. be able to. In addition, the time until the reproduction process can be extended.
[0076]
Further, since the manufacturing method of the exhaust gas purifying apparatus of the present invention is as described above, a holding seal body excellent in heat insulation can be easily and surely wound around the outer peripheral portion of the side surface of the honeycomb filter. In addition, the holding seal body does not shift from side to side during use of the exhaust gas purification apparatus, and an exhaust gas purification apparatus having excellent shape stability can be manufactured, and the ends of the holding seal body are spaced from each other. Even if it forms, exhaust gas does not distribute | circulate through this clearance gap, but the exhaust gas purification apparatus which can purify exhaust gas favorably can be manufactured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an embodiment of an exhaust gas purification apparatus of the present invention.
FIG. 2 is a perspective view schematically showing an example of a honeycomb filter used in the exhaust gas purification apparatus of the present invention.
3A is a perspective view schematically showing a porous ceramic member used in the honeycomb filter shown in FIG. 2, and FIG. 3B is a longitudinal sectional view thereof.
4A is a plan view schematically showing an example of a holding seal body used in the method for manufacturing an exhaust gas purification apparatus of the present invention, and FIG. 4B is a holding seal shown in FIG. It is the perspective view which showed a mode that the body was wound around the honeycomb filter.
FIG. 5A is a perspective view schematically showing an example of a casing used in the exhaust gas purifying apparatus of the present invention, and FIG. 5B is a perspective view schematically showing another example. .
[Explanation of symbols]
10 Exhaust gas purification device
11, 21, 22 Casing
12, 40 Honeycomb filter
13, 41 Holding seal body
14 Electric heater
15 Temperature sensor
16 Introduction pipe
17 Discharge pipe
18 Piping
22a Upper shell
22b Lower shell
23 Upper fixing part
23a, 24a Through hole
24 Lower fixing part
25 volts
30 Porous ceramic sintered body
31 Through hole
32 Filler
33 Bulkhead
42 Convex
43 recess

Claims (6)

An exhaust gas purifying honeycomb filter comprising a porous ceramic sintered body having a large number of through holes arranged in parallel in the longitudinal direction and a partition wall separating the through holes functioning as a filter is an exhaust passage of an internal combustion engine. An exhaust gas purification device installed in a casing connected to the honeycomb filter and a holding seal body interposed between the honeycomb filter and the casing,
The holding seal body contains alumina fibers, titania particles and silica gel, and the heat conductivity of the holding seal body at 800 ° C. is 0.1 W / m · K or less. Gas purification device. The exhaust gas purification device according to claim 1, wherein the holding seal body has a bulk density of 0.20 to 0.50 g / cm ³ . The exhaust gas purification device according to claim 1 or 2, wherein the holding seal body has a convex portion formed at one end portion and a concave portion that can be fitted to the convex portion at the other end portion . An exhaust gas purifying honeycomb filter comprising a porous ceramic sintered body having a large number of through holes arranged in parallel in the longitudinal direction and a partition wall separating the through holes functioning as a filter is an exhaust passage of an internal combustion engine. The holding seal body used in an exhaust gas purification apparatus installed in a casing connected to the honeycomb filter and a holding seal body interposed between the honeycomb filter and the casing,
A holding sealing body comprising alumina fibers, titania particles and silica gel, and having a thermal conductivity at 800 ° C. of 0.1 W / m · K or less . The holding seal body according to claim 4 , wherein the bulk density is 0.20 to 0.50 g / cm ³ . The holding seal body according to claim 4 or 5, wherein a convex portion is formed at one end portion, and a concave portion that can be fitted to the convex portion is formed at the other end portion .

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