JP2022098111A - Exhaust treatment device for diesel engine, and the diesel engine - Google Patents

Abstract

To provide an exhaust treatment device for a diesel engine and the diesel engine capable of actualizing the longer life of the exhaust treatment device by suppressing the heat deterioration progress of a heat insulation material.SOLUTION: An exhaust treatment device 1 for a diesel engine 100 includes a casing 2 storing a diesel oxidation catalyst 4 and a diesel particulate matter trapping filter 3, an exhaust gas flow path 50 formed in the casing 2 for exhaust gas to pass therethrough, a heat insulation material 5 provided at a position adjacent to the exhaust gas flow path 50, and a partition plate 20 provided between the exhaust gas flow path 50 and the heat insulation material 5 for partitioning the exhaust gas flow path 50 and the heat insulation material 5, the partition plate 20 having an air layer formation part 30 to form an air layer 32 between the exhaust gas flow path 50 and the heat insulation material 5.SELECTED DRAWING: Figure 3

Description

The present invention relates to an exhaust treatment device for a diesel engine and a diesel engine.

The exhaust treatment device of a diesel engine, also referred to as a DPF muffler, has a DPF (diesel particulate filter: diesel particulate filter), a DOC (diesel oxidation catalyst) and the like. The DPF collects PM (abbreviation for particulate matter). DOC oxidizes HC (hydrocarbons) and CO (carbon monoxide). The DOC raises the temperature of the exhaust gas and burns the PM in the DPF. The exhaust treatment device measures the pressure using a differential pressure sensor in order to predict the accumulated amount of PM captured by the DPF. The differential pressure sensor detects the differential pressure between the upstream side and the downstream side of the DPF. The exhaust treatment device captures the PM in the exhaust gas by the DPF, and estimates the PM accumulation amount based on the differential pressure between the upstream side and the downstream side of the DPF detected by the differential pressure sensor. When the PM accumulated amount reaches a predetermined regeneration required amount, the exhaust treatment apparatus regenerates the DPF by raising the exhaust temperature and burning and removing the PM deposited on the DPF.

Generally, in an exhaust gas treatment device, it is first necessary to keep the exhaust gas temperature at around 200 ° C. in order to activate the DOC. In addition, since the exhaust gas treatment device itself becomes hot during DPF regeneration, it is necessary to pay attention to the influence of heat damage on peripheral parts. Therefore, a heat insulating material is arranged on the outside of the exhaust gas treatment device. Patent Document 1 discloses an exhaust treatment apparatus having a DPF and a DOC.

In the exhaust treatment device described in Patent Document 1, the flow path of the exhaust gas and the room in which the heat insulating material is incorporated are separated from each other by a single flat plate (cover). Further, since one flat plate is in direct contact with the heat insulating material, the heat insulating material itself becomes hot together with the single flat plate. Therefore, the deterioration of the heat insulating material progresses due to heat. As described above, the exhaust gas treatment device described in Patent Document 1 has room for improvement in terms of extending the life of the exhaust gas treatment device.

Japanese Unexamined Patent Publication No. 2011-208571

The present invention has been made to solve the above problems, and is an exhaust gas treatment device for a diesel engine capable of suppressing deterioration of the heat insulating material due to heat and extending the life of the exhaust gas treatment device. And to provide diesel engines.

The subject is a casing accommodating a diesel oxidation catalyst and a diesel fine particle collection filter, an exhaust gas flow path formed inside the casing through which exhaust gas passes, and heat insulation provided at a position adjacent to the exhaust gas flow path. The material is provided with a partition plate provided between the exhaust gas flow path and the heat insulating material to partition the exhaust gas flow path and the heat insulating material, and the partition plate is provided between the exhaust gas flow path and the heat insulating material. The problem is solved by the exhaust gas treatment device for a diesel engine according to the present invention, which has an air layer forming portion for forming an air layer between the heat insulating material and the heat insulating material.

According to the exhaust gas treatment device of the diesel engine of the present invention, a partition plate for partitioning the exhaust gas flow path and the heat insulating material is arranged between the exhaust gas flow path and the heat insulating material. The partition plate has an air layer forming portion that forms an air layer between the exhaust gas flow path and the heat insulating material. Therefore, the space between the high-temperature exhaust gas flowing through the exhaust gas flow path and the heat insulating material is insulated by the air layer of the air layer forming portion of the partition plate. As a result, deterioration of the heat insulating material can be suppressed from progressing due to heat, and the life of the exhaust gas treatment device can be extended.

In the exhaust gas treatment device of the diesel engine of the present invention, the air layer forming portion is preferably a concavo-convex shape portion having a concave portion and a convex portion.
According to the exhaust gas treatment device of the diesel engine of the present invention, the air layer of the partition plate is separated between the high-temperature exhaust gas flowing through the exhaust gas flow path and the heat insulating material by simply providing an uneven shape portion on the partition plate. It can be insulated by the air layer of the forming part. As a result, it is possible to suppress the deterioration of the heat insulating material due to heat while suppressing the cost increase, and to extend the life of the exhaust treatment device.

In the exhaust gas treatment apparatus of the diesel engine of the present invention, preferably, the heat insulating material and the partition plate are arranged at an end face portion on the exhaust gas introduction portion side for introducing the exhaust gas into the diesel oxidation catalyst. And.
According to the exhaust gas treatment device of the diesel engine of the present invention, the partition plate having the air layer forming portion is arranged with respect to the heat insulating material on the exhaust gas introduction part side where the high temperature exhaust gas is introduced, so that the heat insulating material is deteriorated. It is possible to extend the life of the exhaust gas treatment device by suppressing the progress of the exhaust gas due to heat.

Further, the subject is provided at a position adjacent to the casing accommodating the diesel oxidation catalyst and the diesel fine particle collection filter, the exhaust gas flow path formed inside the casing and passing the exhaust gas, and the exhaust gas flow path. A diesel engine provided with an exhaust treatment device for a diesel engine having a heat insulating material, a partition plate provided between the exhaust gas flow path and the heat insulating material, and a partition plate for partitioning the exhaust gas flow path and the heat insulating material. Further, according to the present invention, the partition plate of the exhaust gas treatment device of the diesel engine has an air layer forming portion for forming an air layer between the exhaust gas flow path and the heat insulating material. It is solved by the diesel engine.

According to the diesel engine of the present invention, a partition plate for partitioning the exhaust gas flow path and the heat insulating material is arranged between the exhaust gas flow path and the heat insulating material of the exhaust gas treatment device. The partition plate has an air layer forming portion that forms an air layer between the exhaust gas flow path and the heat insulating material. Therefore, the space between the high-temperature exhaust gas flowing through the exhaust gas flow path and the heat insulating material is insulated by the air layer of the air layer forming portion of the partition plate. As a result, deterioration of the heat insulating material can be suppressed from progressing due to heat, and the life of the exhaust gas treatment device can be extended.

According to the present invention, it is possible to provide a diesel engine exhaust treatment device and a diesel engine capable of suppressing the deterioration of the heat insulating material from progressing due to heat and extending the life of the exhaust treatment device.

It is sectional drawing which shows the exhaust gas treatment apparatus of the diesel engine which concerns on embodiment of this invention. It is a perspective view which shows the structural example of the region containing the heat insulating material shown in FIG. It is sectional drawing which shows the internal structure of the exhaust gas treatment apparatus shown in FIG. 1 in more detail. FIG. 3 is an enlarged view showing a structural example of the heat insulating material and the air layer forming portion of the partition plate shown in FIG. It is sectional drawing which shows the partition plate and the heat insulating material of the 2nd Embodiment of this invention. It is a figure which shows the comparative example which is outside the scope of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
Since the embodiments described below are suitable specific examples of the present invention, various technically preferable limitations are attached, but the scope of the present invention is particularly limited to the present invention in the following description. Unless otherwise stated, the present invention is not limited to these aspects. Further, in each drawing, the same components are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

<First Embodiment>
(Configuration example of exhaust gas treatment device 1 of diesel engine)
FIG. 1 is a cross-sectional view showing an exhaust treatment device for a diesel engine according to an embodiment of the present invention.
The diesel engine exhaust treatment device 1 shown in FIG. 1 is mounted on, for example, an industrial diesel engine. The industrial diesel engine is mounted on, for example, a construction machine, an agricultural machine, a lawn mowing machine, or the like, but the type of the device on which the diesel engine 100 is mounted is not particularly limited.

The exhaust treatment device (hereinafter referred to as an exhaust treatment device) 1 of the diesel engine 100 is also called a DPF muffler, and has a heat-resistant metal cylindrical casing 2 and a DPF (diesel particulate filter: diesel particulate filter). It has a filter) 3, a DOC (diesel oxidation catalyst) 4, one and the other heat insulating materials 5, 6, an exhaust gas introduction unit 7, an exhaust gas exhaust unit 8, and the like. Casing 2 houses DPF3 and DOC4.

As shown by the arrow, the exhaust gas G discharged from the diesel engine 100 is introduced from the exhaust gas introduction unit 7 into the exhaust gas flow path in the casing 2, and is passed through the DOC 4 to raise the temperature of the exhaust gas G. When HC and CO in the exhaust gas G are oxidized and pass through the DPF3, PM (abbreviation of particulate matter) in the exhaust gas G is collected by the DPF3 and the PM is burned. After that, the exhaust gas G is sent from the exhaust gas discharge unit 8 to the exhaust system of the diesel engine 100.

The diesel engine 100 shown in FIG. 1 is equipped with an exhaust treatment device 1. The position of the casing 2 of the exhaust treatment device 1 near the heat insulating material 6 is fixed to the diesel engine 100 by using brackets, bolts, or the like (not shown). Similarly, the position of the exhaust gas treatment device 1 near the heat insulating material 5 is fixed to the diesel engine 100 by using brackets, bolts, or the like (not shown).

FIG. 2 is a perspective view showing a structural example of the region P including the heat insulating material 5 shown in FIG.
FIG. 3 is a cross-sectional view showing the internal structure of the exhaust gas treatment device 1 shown in FIG. 1 in more detail.
However, the exhaust treatment device 1 shown in FIG. 3 is in a state in which the exhaust treatment device 1 shown in FIG. 1 is rotated by 90 degrees about the central axis FF of the casing 2.

As shown in FIG. 3, the casing 2 has a cylindrical casing heat insulating material 11 in the vicinity of the exhaust gas introduction portion 7. The exhaust gas introduction end face 4A of the DOC 4 is arranged in one opening 12 of the casing heat insulating material 11. The other opening 13 of the casing heat insulating material 11 is sealed by a circular metal sealing plate 14 having heat resistance. A plurality of protrusions 15 are formed on the inner surface of the sealing plate 14. Each protrusion 15 of the sealing plate 14 supports the heat insulating material 5 so as to abut against one surface 5A of the heat insulating material 5. The casing heat insulating material 11 and the heat insulating material 5 are integrated or separated members. The heat insulating material 5 has a ring-shaped metal member 5C for support, and the metal member 5C is fixed to the inner surface of the casing heat insulating material 11 by spot welding at a plurality of places, for example, so that the heat insulating material 5 is a heat insulating material. Positioning when mounting 5 and reinforcement of the heat insulating material 5 are performed.

(Structural example of heat insulating material 5 and partition plate 20)
The heat insulating material 5 shown in FIGS. 2 and 3 is, for example, a circular thick heat insulating plate, and is provided at a position adjacent to the exhaust gas flow path 50 formed inside the casing 2. The heat insulating material 5 has one surface (outer surface) 5A and the other surface (inner surface) 5B. The other surface 5B of the heat insulating material 5 is provided with a circular partition plate 20. The partition plate 20 is arranged between the exhaust gas flow path 50 in the casing 2 and the other surface 5B of the heat insulating material 5, and the partition plate 20 partitions the exhaust gas flow path 50 and the heat insulating material 5. There is. The partition plate 20 is made of a metal plate such as an iron plate having heat resistance, for example. However, the partition plate 20 may be made of a ceramic plate having heat resistance or the like, in addition to the metal plate.

As shown in FIGS. 2 and 3, the partition plate 20 has an air layer forming portion 30 for forming an air layer 32 between the exhaust gas flow path 50 and the other surface 5B of the heat insulating material 5. The air layer forming portion 30 of the partition plate 20 forms an air layer 32 for improving the heat insulating property between the exhaust gas flow path 50 having a high temperature of, for example, about 200 ° C. and the heat insulating material 5.
FIG. 4 is an enlarged cross-sectional view showing a structural example of the heat insulating material 5 and the air layer forming portion 30 of the partition plate 20 shown in FIG.
As shown in FIGS. 3 and 4, the heat insulating material 5 has a constant thickness D over the entire region, and the partition plate 20 is arranged so as to overlap the other surface 5B of the heat insulating material 5.

The partition plate 20 is not a flat plate having a simple structure, and the air layer forming portion 30 is formed by dimple processing or embossing the flat plate using a simple processing device, and is a concave-convex shape portion having concave portions and convex portions. be. In the present specification, the dimple processing is a processing method in which the surface of a flat plate is continuously recessed, for example, in a hemispherical shape. On the contrary, the embossing is a processing method in which the back surface of the flat plate is pushed up in a dot shape to float and the back surface is dented, and the back surface is raised from the back surface of the flat plate.

As shown in FIG. 4, the air layer forming portion 30 of the partition plate 20 forms a heat insulating air layer 32 between the exhaust gas flow path 50 and the other surface 5B of the heat insulating material 5. In the examples shown in FIGS. 3 and 4, the uneven shape portion of the air layer forming portion 30 of the partition plate 20 is formed by dimple processing a flat plate. Since each convex portion 31 is formed, for example, in the shape of a dome or an arc in cross section, between the inner surface of the partition plate 20 and the other surface 5B of the heat insulating material 5, the other surface 5B of the heat insulating material 5 is formed. The air layer 32 can be formed over the entire surface.

The air layer 32 is a layer of air completely separated from the exhaust gas flow path 50 in the casing 2 by a partition plate 20. The partition plate 20 is arranged on the other surface 5B side of the heat insulating material 5, and the partition plate 20 has an air layer forming portion 30. As a result, since there is an air layer 32 of the air layer forming portion 30, when the high-temperature exhaust gas G introduced from the exhaust gas introducing portion 7 of FIG. 1 passes through the exhaust gas flow path 50 shown in FIG. The heat of the high-temperature exhaust gas G passing through the exhaust gas flow path 50 is prevented from being directly transferred to the heat insulating material 5, and the heat transfer property is lowered. Therefore, it is possible to suppress the heat of the high-temperature exhaust gas G from thermally deteriorating the heat insulating material 5. The partition plate 20 can suppress the deterioration of the heat insulating material 5 from progressing due to heat, prevent the heat insulating material 5 from being worn by the exhaust gas G, and improve the durability of the heat insulating material 5. By arranging the partition plate 20 having the air layer forming portion 30, the compression range of the heat insulating material 5 can be reduced, and the heat received by the high-temperature exhaust gas can be reduced, so that the curing of the heat insulating material 5 can be suppressed. .. Therefore, the life of the heat insulating material 5 and the exhaust gas treatment device 1 can be extended.

Further, since the air layer 32 is formed between the partition plate 20 and the other surface 5B of the heat insulating material 5, the heat retention performance of the high-temperature exhaust gas passing through the exhaust gas flow path 50 can be improved, and the exhaust treatment can be performed. Deterioration of the processing performance of the device 1 can be suppressed. Further, since the partition plate 20 is not a flat plate and the air layer forming portion 30 is a concave-convex shape member having concave portions and convex portions, the partition plate 20 increases the mechanical rigidity as compared with the partition plate of the flat plate. The partition plate 20 can be suppressed from being deformed by the vibration of the exhaust treatment device 1. The partition plate 20 makes partial contact with the other surface 5B of the heat insulating material 5 instead of full contact. The heat insulating material 5 can improve the heat retention performance of the exhaust gas in the exhaust gas flow path 50 on the DOC4 side.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a cross-sectional view showing the partition plate 20 and the heat insulating material 5 according to the second embodiment of the present invention.
As shown in FIG. 5, the partition plate 20 is not a simple flat plate, and the air layer forming portion 30A is formed by embossing the flat plate, for example, and is a concave-convex shape portion having concave portions and convex portions. .. Each convex portion 31A of the air layer forming portion 30A is not a dome shape but a diamond shape or a pyramid shape. The air layer forming portion 30A of the partition plate 20 can form a heat insulating air layer 32A between the exhaust gas flow path 50 and the other surface 5B of the heat insulating material 5. The action and effect exhibited by the second embodiment of the present invention are the same as the action and effect of the first embodiment of the present invention described above.

As described above, in the diesel engine exhaust treatment device 1 and the diesel engine 100 of the embodiment of the present invention, the exhaust gas flow path 50 and the heat insulating material 5 are provided between the exhaust gas flow path 50 and the heat insulating material 5. A partition plate 20 is arranged, and the partition plate 20 has an air layer forming portion 30 and 30A forming an air layer 32 and 32A between the exhaust gas flow path 50 and the heat insulating material 5. As a result, the space between the high-temperature exhaust gas G flowing in the exhaust gas flow path 50 and the heat insulating material 5 is insulated by the air layers 32, 32A of the air layer forming portions 30, 30A of the partition plate 20, so that the heat insulating material 5 is used. It is possible to prevent the deterioration of the heat insulating material 5 from progressing due to heat and to extend the life of the heat insulating material 5 and the exhaust gas treatment device 1.

With a simple configuration in which the partition plate 20 is provided with an uneven shape portion, the air in the air layer forming portions 30 and 30A of the partition plate 20 is sandwiched between the high-temperature exhaust gas G flowing through the exhaust gas flow path 50 and the heat insulating material 5. It can be insulated by the layers 32 and 32A. Therefore, it is possible to suppress the deterioration of the heat insulating material 5 due to heat while suppressing the cost increase.

The uneven shape portion of the partition plate 20 can be easily formed only by dimple processing or embossing the flat plate. Therefore, the cost increase can be further suppressed. Since the partition plate 20 having the air layer forming portions 30 and 30A is arranged with respect to the heat insulating material 5 on the exhaust gas introduction portion 7 side into which the high temperature exhaust gas G is introduced, the deterioration of the heat insulating material 5 progresses due to heat. Can be further suppressed.

<Comparison example>
FIG. 6 is a diagram showing a comparative example outside the scope of the present invention.
FIG. 6 shows an example in which the flat partition plate 120 is arranged on the other surface 105B of the heat insulating material 105 as a comparative example. In the comparative example, since the flat plate partition plate 120 is arranged in close contact with the entire surface of the other surface 105B, no air layer is formed between the partition plate 120 and the other surface 105B. It is not possible to obtain the effects of the first embodiment of the present invention.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of claims. The configuration of the above embodiment may be partially omitted or may be arbitrarily combined so as to be different from the above.
For example, the heat insulating material 5 shown in FIG. 3 adopts a structure including a partition plate 20 having air layer forming portions 30 and 30A. However, the other heat insulating material 6 shown in FIG. 3 may adopt a structure including a partition plate having an air layer forming portion similar to that of the partition plate 20. The shape of each of the convex portions of the air layer forming portions 30 and 30A is not limited to the illustrated example, and can be arbitrarily selected.
For example, in the illustrated example, the exhaust gas flow path 50 of the casing 2 is a cylindrical member having a circular cross section, but the exhaust gas flow path of the casing may have a rectangular cross section, for example. In this case, the heat insulating material and the partition member have a rectangular shape instead of a circular shape according to the shape of the exhaust gas flow path.

1: Exhaust gas treatment device, 2: Casing, 3: DPF, 4: DOC, 4A: Exhaust gas introduction end face, 5: Insulation material, 5A: One side, 5B: The other side, 5C: Metal member, 6: Insulation Material, 7: Exhaust gas introduction part, 8: Exhaust gas discharge part, 11: Casing insulation material, 12: Opening, 13: Opening, 14: Sealing plate, 15: Protrusion, 20: Partition plate, 30: Air Layer forming part, 30A: Air layer forming part, 31: Convex part, 31A: Convex part, 32: Air layer, 32A: Air layer, 50: Exhaust gas flow path, 100: Diesel engine, 105: Insulation material, 105B: The other side, 120: divider, D: thickness, G: exhaust gas, P: area

Claims (4)

A casing containing a diesel oxidation catalyst and a diesel particulate collection filter,
An exhaust gas flow path formed inside the casing and passing exhaust gas,
A heat insulating material provided at a position adjacent to the exhaust gas flow path,
A partition plate provided between the exhaust gas flow path and the heat insulating material and partitioning the exhaust gas flow path and the heat insulating material,
Equipped with
The partition plate is an exhaust treatment device for a diesel engine, characterized by having an air layer forming portion for forming an air layer between the exhaust gas flow path and the heat insulating material. The exhaust gas treatment device for a diesel engine according to claim 1, wherein the air layer forming portion is a concave-convex shape portion having a concave portion and a convex portion. The exhaust gas of a diesel engine according to claim 1 or 2, wherein the heat insulating material and the partition plate are arranged at an end face portion on the exhaust gas introduction portion side for introducing the exhaust gas into the diesel oxidation catalyst. Processing equipment. A casing containing a diesel oxidation catalyst and a diesel particulate collection filter,
An exhaust gas flow path formed inside the casing and passing exhaust gas,
A heat insulating material provided at a position adjacent to the exhaust gas flow path,
A partition plate provided between the exhaust gas flow path and the heat insulating material and partitioning the exhaust gas flow path and the heat insulating material,
A diesel engine equipped with an exhaust treatment device for a diesel engine
A diesel engine, wherein the partition plate of the exhaust gas treatment device of the diesel engine has an air layer forming portion for forming an air layer between the exhaust gas flow path and the heat insulating material.

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