WO2011114823A1

WO2011114823A1 - Exhaust gas purification device

Info

Publication number: WO2011114823A1
Application number: PCT/JP2011/053007
Authority: WO
Inventors: 匡孝光田
Original assignee: ヤンマー株式会社
Priority date: 2010-03-17
Filing date: 2011-02-14
Publication date: 2011-09-22
Also published as: JP2011196193A; JP5467900B2

Abstract

Disclosed is an exhaust gas purification device which improves the purification of exhaust gas from an engine (70) while improving the handling workability, such as maintenance, of the engine (70). A diesel particulate filter (DPF) (1) is provided with: a diesel oxidation catalyst (2) for purifying the exhaust gas emitted from the diesel engine (70); a soot filter (3) for purifying the exhaust gas emitted from the diesel engine (70); a catalyst inner case (4) for housing the diesel oxidation catalyst (2); and a filter inner case (20) for housing the soot filter (3). The DPF (1) is fitted to and connects the gas exhaust side of the catalyst inner case (4) and the gas intake side of the filter inner case (20), and the catalyst inner case (4) and the filter inner case (20) are each formed in a cylindrical shape having the same diameter on the respective exhaust gas intake side and emission side or each. Furthermore, either the catalyst inner case (4) or the filter inner case (20) is formed so as to have a smaller diameter than the other.

Description

Exhaust gas purification device

The present invention relates to an exhaust gas purification device mounted on a diesel engine or the like, and more particularly to an exhaust gas purification device that removes particulate matter (soot, particulates) and the like contained in exhaust gas. .

Conventionally, a diesel particulate filter (hereinafter referred to as DPF) is provided as an exhaust gas purification device (post-treatment device) in the exhaust path of a diesel engine, and the exhaust gas discharged from the diesel engine is purified by the DPF. Is known (see, for example, Patent Document 1).

In addition, a technique for providing a temperature sensor for detecting the temperature of exhaust gas discharged from a diesel engine and a pressure sensor for detecting the pressure of exhaust gas discharged from a diesel engine in a DPF is also known (for example, Patent Documents 1 to 4). 2).

Also, in the DPF, a technique is known in which an inner case is provided in a double structure inside an outer case, and an oxidation catalyst or a soot filter is provided in the inner case (see, for example, Patent Document 3).

In the DPF, there is also known a technique of detachably connecting a case containing an oxidation catalyst and a case containing a soot filter through a flange fastened by a bolt (see, for example, Patent Documents 4 to 5). .

JP 2004-263593 A JP 2001-73748 A JP 2005-194949 A JP 2009-228516 A Japanese Unexamined Patent Publication No. 2009-91982

In the prior art, the upstream gas purification body case and the downstream gas purification body case are the same in a structure that connects a single structure case in which an oxidation catalyst is installed and a single structure case in which a soot filter is installed. Formed with a cylindrical body having a diameter, an enlarged diameter portion is provided in one gas purification body case, the other gas purification body case is inserted into the expanded diameter portion, and an upstream gas purification body and a downstream gas purification body Were placed close together. The prior art requires a process of providing an enlarged diameter portion in the gas purifier case, and there is a problem that the processing cost of the gas purifier case cannot be reduced. Further, by providing a step between the exhaust gas intake side and the exhaust side of the gas purifier case and forming an enlarged diameter portion, the gas purifier case is identified due to repeated thermal expansion and contraction. There is a problem that the thermal stress is locally concentrated on the part.

Therefore, the present invention seeks to provide an exhaust gas purifying apparatus which has been improved by examining these current conditions.

According to the first aspect of the present invention, an upstream gas purification body that purifies the exhaust gas discharged from the engine, a downstream gas purification body that purifies the exhaust gas discharged from the engine, and the upstream gas purification body are provided. An upstream gas purification body case; and a downstream gas purification body case in which the downstream gas purification body is installed; a gas discharge side of the upstream gas purification body case; and a gas in the downstream gas purification body case In the exhaust gas purification apparatus that is fitted and connected to the intake side, the upstream gas purification body case and the downstream gas purification body case are formed into a cylindrical shape having the same diameter on the exhaust gas intake side and the exhaust side, Either the upstream gas purification body case or the downstream gas purification body case is formed to have a smaller diameter than the other.

According to a second aspect of the present invention, an upstream side gas purification body for purifying exhaust gas discharged from the engine, a downstream side gas purification body for purifying exhaust gas discharged from the engine, and the upstream side gas purification body are provided. An upstream gas purification body case; and a downstream gas purification body case in which the downstream gas purification body is installed; a gas discharge side of the upstream gas purification body case; and a gas in the downstream gas purification body case In the exhaust gas purification apparatus that is fitted and connected to the intake side, the upstream gas purification body case and the downstream gas purification body case are formed in a cylindrical shape in which the ridgeline of the outer diameter thereof is a straight line without a step. The gas outlet of the upstream gas purification body case and the gas inlet of the downstream gas purification body case are formed with different diameters.

The invention of claim 3 is the exhaust gas purification device according to

claim

1 or 2, wherein either the upstream gas purification body case or the downstream gas purification body case is formed with a larger diameter than the other, On the gas discharge side (or the gas intake side of the downstream gas purification body case) of the upstream gas purification body case on the large diameter side, the gas intake side (or the upstream side) of the downstream gas purification body case on the small diameter side The gas purifier case gas discharge side) is inserted.

According to a fourth aspect of the present invention, in the exhaust gas purification device according to the first or second aspect, the downstream gas purification body case is formed to have a smaller diameter than the upstream gas purification body case, and the upstream side of the large diameter side. A gas intake side of the downstream gas purification body case on the small diameter side is inserted into the gas discharge side of the gas purification body case.

According to a fifth aspect of the present invention, in the exhaust gas purifying device according to the first or second aspect, the upstream gas purification body case is formed to have a smaller diameter than the downstream gas purification body case, and the downstream gas on the small diameter side is formed. The gas discharge side of the upstream side gas purification body case on the large diameter side is inserted into the gas intake side of the purification body case.

The invention according to claim 6 is the exhaust gas purification device according to

claim

1 or 2, wherein the gas discharge side of the upstream gas purification body case and the gas intake side of the downstream gas purification body case are formed to have different diameters, The gas discharge side of the side gas purification body case and the gas intake side of the downstream side gas purification body case are fitted and connected.

According to a seventh aspect of the present invention, in the exhaust gas purification device according to the first or second aspect, an outer case body is fitted on an outer periphery of a connection portion between the upstream side gas purification body case and the downstream side gas purification body case. Is.

According to an eighth aspect of the present invention, in the exhaust gas purifying apparatus according to the sixth aspect, a detachable gap for fitting into a double structure is provided between the upstream gas purification body case and the downstream gas purification body case. Formed.

According to a ninth aspect of the present invention, in the exhaust gas purification apparatus according to the first or second aspect, the gas discharge side of the upstream case in which the upstream gas purification body is provided and the downstream case in which the downstream gas purification body is provided. A joining flange is formed on each gas intake side, and a sandwiching body is detachably fitted to each joining flange of each case, and the sandwiching body is detachably fastened by a fastening band body. Is.

According to the first aspect of the present invention, the upstream side gas purification body for purifying the exhaust gas discharged from the engine, the downstream side gas purification body for purifying the exhaust gas discharged from the engine, and the upstream side gas purification body are provided internally. An upstream gas purification body case, and a downstream gas purification body case in which the downstream gas purification body is installed, a gas discharge side of the upstream gas purification body case, and a downstream gas purification body case In the exhaust gas purification device that is fitted and connected to the gas intake side, the upstream gas purification body case and the downstream gas purification body case are formed in a cylindrical shape having the same diameter on the exhaust gas intake side and the exhaust side, Since either one of the upstream gas purification body case or the downstream gas purification body case is formed to have a smaller diameter than the other, the upstream gas purification body case formed of a cylindrical body having the same diameter. Compared to the prior art in which either one of the gas purification body case and the downstream gas purification body case is provided with an enlarged diameter portion, it is not necessary to provide the enlarged diameter portion in the gas purification body case, and the gas purification body case has a straight ridge line. Therefore, the process of providing the enlarged diameter portion in one gas purification body case becomes unnecessary, and the processing cost of the gas purification body case can be reduced. In addition, since it is not necessary to provide a step between the exhaust gas intake side and the exhaust side of the gas purification body case to form an enlarged diameter portion, the gas purification body case is caused by repeated thermal expansion and contraction. It is possible to reduce the local concentration of thermal stress on the specific part, and to improve the durability of the gas purifier case.

According to the invention of claim 2, the upstream side gas purification body for purifying the exhaust gas discharged from the engine, the downstream side gas purification body for purifying the exhaust gas discharged by the engine, and the upstream side gas purification body are provided internally. An upstream gas purification body case, and a downstream gas purification body case in which the downstream gas purification body is installed, a gas discharge side of the upstream gas purification body case, and a downstream gas purification body case In the exhaust gas purification device that is fitted and connected to the gas intake side, the upstream gas purification body case and the downstream gas purification body case are formed in a cylindrical shape in which the ridgelines of their outer diameters are straight without any step. In addition, since the gas outlet of the upstream gas purification body case and the gas inlet of the downstream gas purification body case are formed with different diameters, the gas purification body case is provided with an enlarged diameter portion as compared with the prior art. Not necessary, provided the enlarged diameter portion on one of the gas purifier case processing is not required, thereby reducing the processing cost of the gas purifier case. In addition, since it is not necessary to provide a step between the exhaust gas intake side and the exhaust side of the gas purification body case to form an enlarged diameter portion, the gas purification body case is caused by repeated thermal expansion and contraction. It is possible to reduce the local concentration of thermal stress on the specific part, and to improve the durability of the gas purifier case.

According to the invention of claim 3, either the upstream gas purification body case or the downstream gas purification body case is formed to have a larger diameter than the other, and the gas in the upstream gas purification body case on the large diameter side is formed. The gas intake side (or the gas discharge side of the upstream gas purification body case) on the small diameter side is inserted into the discharge side (or the gas intake side of the downstream gas purification body case). Therefore, the gas intake side of the downstream gas purification body case can be easily put in and out of the gas discharge side of the upstream gas purification body case on the large diameter side. Assembling / disassembling workability of the downstream gas purification body case can be improved.

According to the invention of claim 4, the downstream gas purification body case is formed to have a smaller diameter than the upstream gas purification body case, and the gas discharge side of the upstream gas purification body case on the large diameter side has a smaller diameter side. Since it is configured to insert the gas intake side of the downstream gas purification body case, the processing cost of the gas purification body case can be reduced compared to the prior art, and moreover, due to repeated thermal expansion and contraction. As a result, it is possible to reduce the local concentration of thermal stress on a specific part of the gas purifier case, and to improve the durability of the gas purifier case. Since the flange for connecting the upstream gas purification body case and the downstream gas purification body case can be disposed at the outer peripheral position of the downstream gas purification body case, the upstream gas purification body case is utilized. Assembling / disassembling workability on the downstream gas purifier case side having a gas outlet pipe (silencer) and the like can be improved.

According to the invention of claim 5, the upstream gas purification body case is formed to have a smaller diameter than the downstream gas purification body case, and the downstream side gas purification body case on the small diameter side has a large diameter side. Since it is configured to insert the gas discharge side of the upstream gas purification body case, the processing cost of the gas purification body case can be reduced compared to the prior art, and also due to repeated thermal expansion and contraction As a result, it is possible to reduce the local concentration of thermal stress on a specific part of the gas purifier case, and to improve the durability of the gas purifier case. Since the flange for connecting the upstream gas purification body case and the downstream gas purification body case can be disposed at the outer peripheral position of the upstream gas purification body case, the downstream gas purification body case is utilized. Assembling / disassembling workability on the upstream side gas purifier case side having a gas inlet pipe and the like can be improved.

According to the invention of claim 6, the gas discharge side of the upstream gas purification body case and the gas intake side of the downstream gas purification body case are formed to have different diameters, and the gas discharge side and the downstream gas of the upstream gas purification body case are formed. Since the gas intake side of the purifier case is configured to be fitted and connected, the gas intake side and the gas discharge side of the gas purifier case are formed to have the same diameter, or the ridge line is a cylindrical truncated cone shape. Since the gas purification body case can be formed in comparison with the prior art, the processing cost of the gas purification body case can be reduced, and moreover, heat is applied to a specific part of the gas purification body case due to repeated thermal expansion and contraction. The concentration of stress locally can be reduced, and the durability of the gas purifier case can be improved. In the case of the gas purification body case having the same diameter on the gas intake side and the gas discharge side, the gas purification body case can be easily formed by cutting a long pipe. When the gas purification body case has a truncated cone shape, it is possible to improve the assembly / disassembly workability of the gas purification body cases such as fitting or extraction operations on the gas intake side and the gas discharge side.

According to the invention of claim 7, since the outer case body is fitted on the outer periphery of the connecting portion between the upstream gas purification body case and the downstream gas purification body case, the upstream gas purification body case and The downstream gas purification body case can be protected, and the temperature drop in each case can be reduced. A support bracket can be installed on the outer case body with high rigidity, and the support strength of the DPF can be improved.

According to the eighth aspect of the present invention, the upstream side gas purification body case and the downstream side gas purification body case are formed with a detachable gap for fitting into a double structure. The purification body case and the downstream gas purification body case can be attached and detached with a simple operation. That is, for example, in order to prevent the exhaust gas from leaking from the connecting portion between the upstream gas purification body case and the downstream gas purification body case, the upstream gas purification body case and the downstream gas purification body case are When these connection portions are brought into close contact with each other, the upstream gas purification body case and the downstream gas purification body case are integrated by rust or the like, and the upstream gas purification body case and the downstream gas purification body case can be easily combined. Could not be separated. Compared with the prior art, the upstream gas purification body case and the downstream gas purification body case can be easily separated, and the maintenance and replacement workability of the gas purification body can be improved.

According to the invention of claim 9, a joining flange is formed respectively on the gas discharge side of the upstream case where the upstream gas purification body is provided and on the gas intake side of the downstream case where the downstream gas purification body is provided, Since the sandwiching body is detachably fitted to each joint flange of each case, and the sandwiching body is detachably fastened by the tightening band body, the attaching and detaching operation of the tightening band body is performed. The sandwiching body can be easily attached and detached, and the gas intake side of the downstream gas purification body case can be easily separated or joined to the gas discharge side of the upstream gas purification body case. For example, even if the gas purification body case is installed in a narrow space (such as inside an engine room), particulate matter or the like accumulated in the downstream gas purification body can be removed by a simple attachment / detachment operation, and the downstream Maintenance workability such as cleaning the inside of the side gas purification body case can be improved.

It is a section explanatory view of DPF which shows a 1st embodiment. It is an external appearance perspective view of DPF. It is an external appearance top view of DPF. It is an external appearance bottom view of DPF. It is an external appearance front view of DPF. It is an external appearance side view of DPF. It is a cross-sectional side view of the upstream of DPF. It is a cross-sectional side view of the downstream of DPF. It is decomposition | disassembly cross-section explanatory drawing of DPF. It is a separation side view of a clamping flange (semi-arc body). It is an expanded side sectional view of a catalyst side joining flange. It is an expanded sectional view showing the attachment part of a sensor boss body. It is a top view of the diesel engine which provided DPF. It is sectional explanatory drawing which shows the catalyst inner case and filter inner case of 2nd Embodiment. It is sectional explanatory drawing which shows the catalyst inner case and filter inner case of 3rd Embodiment. It is sectional explanatory drawing which shows the catalyst inner case and filter inner case of 4th Embodiment. It is sectional explanatory drawing which shows the catalyst inner case and filter inner case of 5th Embodiment. It is sectional explanatory drawing which shows the catalyst inner case and filter inner case of 6th Embodiment. It is sectional explanatory drawing which shows the catalyst inner case and filter inner case of 7th Embodiment. It is an external appearance perspective view which shows the junction part of the catalyst inner case and filter inner case of 8th Embodiment. It is the same section explanatory view. FIG. It is decomposition | disassembly explanatory drawing of FIG.

Hereinafter, a first embodiment of an exhaust gas purification apparatus embodying the present invention will be described with reference to FIGS. 1 to 13. A continuously regenerating diesel particulate filter 1 (hereinafter referred to as DPF 1) as an exhaust gas purification device is provided. In addition to the removal of particulate matter (PM) in the exhaust gas of the diesel engine 70, the DPF 1 is configured to reduce carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas of the diesel engine 70. Yes.

As shown in FIG. 1, FIG. 6, and FIG. 13, the DPF 1 as the exhaust gas purification device is for collecting particulate matter (PM) and the like in the exhaust gas. The DPF 1 is configured in a substantially cylindrical shape extending long in the left-right direction intersecting the output shaft (crankshaft) of the diesel engine 70 in plan view. The DPF 1 is disposed on the flywheel housing 78 of the diesel engine 70. An exhaust gas inlet pipe 16 (exhaust gas intake side) and an exhaust gas outlet pipe 34 (exhaust gas discharge side) are provided on the left and right sides of the DPF 1 (one end side and the other end side in the exhaust gas movement direction). It distributes to the left and right. The exhaust gas inlet pipe 16 on the exhaust gas intake side of the DPF 1 is detachably bolted to the exhaust manifold 71 of the diesel engine 70. A tail pipe 107 is connected to the exhaust gas outlet pipe 34 on the exhaust gas discharge side of the DPF 1.

As shown in FIGS. 1 to 6, the DPF 1 includes a DPF casing 60 made of a refractory metal material and a diesel oxidation catalyst 2 such as platinum and a soot filter 3 having a honeycomb structure through a cylindrical

inner cases

4 and 20. It is a structure accommodated in series. The DPF 1 is attached to the flywheel housing 78 via a flange side bracket leg 61 and a casing side bracket leg 62 as a support. In this case, one end side of the flange-side bracket leg 61 is detachably bolted to the outer peripheral side of the DPF casing 60 via a flange 40 described later. One end side of the casing side bracket leg 62 is integrally fixed to the outer peripheral surface of the DPF casing 60 by welding.

On the other hand, as shown in FIGS. 1 to 6 and FIG. 13, the other end of the flange side bracket leg 61 is detachably fastened to the upper surface (DPF mounting portion) of the flywheel housing 78 with two retrofitting bolts 88. The The other end side of the casing side bracket leg 62 is detachably fastened to the upper surface (DPF attachment portion) of the flywheel housing 78 with a front bolt 87 and a rear bolt 88. On the other end side of the casing side bracket leg 62, a notch groove 89 for engaging the attaching bolt 87 is formed.

That is, when the DPF 1 is assembled to the diesel engine 70, first, the leading bolt 87 is screwed incompletely on the upper surface of the flywheel housing 78. Then, the operator lifts the DPF 1 with both hands, the casing side bracket leg 62 is locked to the leading bolt 87 through the notch groove 89, and the DPF 1 is temporarily fixed to the diesel engine 70. In this state, the operator can release both hands from the DPF 1. Thereafter, the inlet flange body 17 is fastened to the exhaust manifold 71, and the exhaust gas inlet pipe 16 is fixed to the exhaust manifold 71.

On the other hand, the flange side bracket leg 61 and the casing side bracket leg 62 are fastened to the upper surface of the flywheel housing 78 by three retrofitting bolts 88. Further, the front bolt 87 is also completely fastened, and the DPF 1 is detachably fixed to the upper surface of the flywheel housing 78. The DPF 1 can be removed in the reverse procedure. As a result, the DPF 1 is stably connected and supported to the rear part of the diesel engine 70 by the

bracket legs

61 and 62 and the exhaust manifold 71 at the upper part of the flywheel housing 78 that is a highly rigid member. Moreover, the attachment or detachment operation | work of DPF1 to the diesel engine 70 can be performed by one operator.

With the above configuration, the exhaust gas of the diesel engine 70 flows from the exhaust manifold 71 of the diesel engine 70 to the diesel oxidation catalyst 2 side in the DPF casing 60, and moves from the diesel oxidation catalyst 2 to the soot filter 3 side for purification. It is processed. Particulate matter in the exhaust gas cannot pass through the porous partition walls between the cells in the soot filter 3. That is, the particulate matter in the exhaust gas is collected by the soot filter 3. Thereafter, exhaust gas that has passed through the diesel oxidation catalyst 2 and the soot filter 3 is discharged to the tail pipe 107.

When the exhaust gas passes through the diesel oxidation catalyst 2 and the soot filter 3, the exhaust gas temperature exceeds the reproducible temperature (for example, about 300 ° C.). NO (nitrogen monoxide) is oxidized to unstable NO ₂ (nitrogen dioxide). The particulate matter collected by the soot filter 3 is oxidized and removed by O (oxygen) released when NO ₂ returns to NO. In addition, when particulate matter accumulates on the soot filter 3, the particulate matter is oxidized and removed by maintaining the temperature of the exhaust gas at a temperature higher than the recyclable temperature. Is recovered (the soot filter 3 is regenerated).

1 and 9, a structure for assembling a diesel oxidation catalyst 2 that is an example of an exhaust gas purifier (filter) that purifies exhaust gas discharged from the diesel engine 70 will be described. The diesel oxidation catalyst 2 is provided in a substantially cylindrical catalyst inner case 4 made of a heat-resistant metal material. The catalyst inner case 4 is formed in a substantially cylindrical catalyst outer case 5 made of a heat-resistant metal material. That is, the catalyst inner case 4 is fitted on the outside of the diesel oxidation catalyst 2 via the ceramic heat insulating material 6 made of ceramic fiber. A catalyst heat insulating material 6 is press-fitted between the diesel oxidation catalyst 2 and the catalyst inner case 4 to protect the diesel oxidation catalyst 2.

Further, the catalyst outer case 5 is fitted to the outside of the catalyst inner case 4 via an end plate L-shaped support 7. The catalyst outer case 5 is one of the elements that constitute the DPF casing 60 described above. Note that the diesel oxidation catalyst 2 is protected by the catalyst heat insulating material 6. The stress (mechanical vibration, deformation force) of the catalyst outer case 5 transmitted to the catalyst inner case 4 is reduced by the thin plate support 7.

As shown in FIGS. 1 and 9, a disc-shaped side cover 8 is fixed to one end of the catalyst inner case 4 and the catalyst outer case 5 by welding. An outer lid body 9 is fastened to the outer surface side of the side lid body 8 with bolts and nuts. The gas inflow side end face 2a of the diesel oxidation catalyst 2 and the side lid 8 are separated by a certain distance L1 (gas inflow space 11). An exhaust gas inflow space 11 is formed between the gas inflow side end face 2 a of the diesel oxidation catalyst 2 and the left lid 8. An exhaust gas inlet 12 facing the exhaust gas inflow space 11 is opened in the catalyst inner case 4 and the catalyst outer case 5. A closing ring body 15 is fixed between the opening edge of the catalyst inner case 4 and the opening edge of the catalyst outer case 5 in a sandwiched manner. Since the gap between the opening edge of the catalyst inner case 4 and the opening edge of the catalyst outer case 5 is closed by the closing ring 15, the exhaust gas flows between the catalyst inner case 4 and the catalyst outer case 5. Can be prevented.

1 to 6 and 9, an exhaust gas inlet pipe 16 is arranged on the outer surface of the catalyst outer case 5 in which the exhaust gas inlet 12 is formed. An inlet flange body 17 is welded and fixed to one open end of the exhaust gas inlet pipe 16. The inlet flange body 17 is detachably bolted to the exhaust manifold 71 of the diesel engine 70. One end of the exhaust gas inlet pipe 16 communicates with the exhaust manifold 71. The other open end of the exhaust gas inlet pipe 16 is welded to the outer surface of the catalyst outer case 5 so as to cover the exhaust gas inlet 12 from the outside. A pair of reinforcing bracket bodies 18 are fixed by welding between the outer surface of the catalyst outer case 5 and the side edges of the inlet flange body 17 to ensure the connection strength between the exhaust manifold 71 and the exhaust gas inlet pipe 16.

With the above configuration, the exhaust gas of the diesel engine 70 enters the exhaust gas inlet pipe 16 from the exhaust manifold 71, enters the exhaust gas inflow space 11 from the exhaust gas inlet pipe 16 via the exhaust gas inlet 12, and the diesel oxidation catalyst. 2 is supplied from the gas inflow side end surface 2a on the left side. Nitrogen dioxide (NO ₂ ) is generated by the oxidation action of the diesel oxidation catalyst 2.

Referring to FIGS. 1 and 9, a structure for assembling a soot filter 3 as an example of an exhaust gas purifier (filter) that purifies exhaust gas discharged from the diesel engine 70 will be described. The soot filter 3 is provided in a substantially cylindrical filter inner case 20 made of a heat-resistant metal material. The filter inner case 20 is provided in a substantially cylindrical filter outer case 21 made of a heat-resistant metal material. That is, the filter inner case 20 is fitted on the outside of the soot filter 3 through the mat-shaped filter heat insulating material 22 made of ceramic fiber. The filter outer case 21 is one of the elements constituting the DPF casing 60 described above together with the catalyst outer case 5. In addition, the filter heat insulating material 22 is press-fitted between the soot filter 3 and the filter inner case 20 to protect the soot filter 3.

As shown in FIGS. 1 and 9, the catalyst inner case 4 formed in a cylindrical shape with a straight ridge line is a downstream side into which an upstream side cylinder portion 4 a for accommodating the diesel oxidation catalyst 2 and a filter inner case 20 described later are inserted. It is comprised by the side cylinder part 4b. In addition, the upstream side cylinder part 4a and the downstream side cylinder part 4b are cylinders of substantially the same diameter. Furthermore, a thin plate-shaped ring-shaped catalyst side joining flange 25 that is welded and fixed to the outer periphery of the catalyst inner case 4 and a thin plate-shaped ring-shaped filter side joining flange 26 that is welded to the outer periphery of the filter inner case 20 are provided. The catalyst-side joining flange 25 and the filter-side joining flange 26 are formed in a donut shape having an L-shaped cross section.

The inner peripheral side of the L-shaped cross-section end face of the catalyst side joining flange 25 is welded and fixed to the end of the downstream side cylinder portion 4b of the catalyst inner case 4. The outer peripheral side of the L-shaped cross-section end face of the catalyst side joining flange 25 is projected toward the outer peripheral side (radial direction) of the catalyst outer case 5. An outer support step portion 25 a is formed at the bent corner portion of the L-shaped end face of the catalyst side joining flange 25. The downstream end of the catalyst outer case 5 is fixed to the outer support step 25a by welding.

On the other hand, the inner peripheral side of the L-shaped cross-section end face of the filter-side joining flange 26 is welded and fixed to the middle part of the filter inner case 20 in the exhaust gas movement direction. The outer peripheral side of the L-shaped cross-section end face of the filter-side joining flange 26 is projected toward the outer peripheral side (radial direction) of the filter outer case 21. A step portion 26 a is formed at the bent corner of the L-shaped end face of the filter-side joining flange 26. The upstream end of the filter outer case 21 is fixed by welding to the step portion 26a. In addition, the filter inner case 20 is formed in a cylindrical shape whose ridgeline is a straight line. The exhaust gas upstream end and the downstream end of the filter inner case 20 are cylinders having substantially the same diameter.

Also, the outer diameter of the diesel oxidation catalyst 2 and the outer diameter of the soot filter 3 are formed to be equal. Compared with the thickness of the filter heat insulating material 22, the thickness of the catalyst heat insulating material 6 is formed larger. On the other hand, the catalyst inner case 4 and the filter inner case 20 are formed of the same plate thickness material. The outer diameter of the filter inner case 20 is made smaller than the inner diameter of the downstream cylindrical portion 4 b of the catalyst inner case 4. A downstream gap 23 is formed between the inner peripheral surface of the catalyst inner case 4 and the outer peripheral surface of the filter inner case 20. The downstream gap 23 is formed to have a dimension (for example, 2 millimeters) larger than the thickness (for example, 1, 5 millimeters) of each of the

cases

4 and 20. For example, even if the

cases

4 and 20 are rusted or thermally deformed, the exhaust gas upstream end of the filter inner case 20 can be easily put in and out of the downstream cylindrical portion 4 b of the catalyst inner case 4.

1 to 5, 9, and 12, the catalyst side joining flange 25 and the filter side joining flange 26 are brought into contact with each other through the gasket 24. The

joint flanges

25 and 26 are sandwiched from both sides in the exhaust gas movement direction by a pair of thick plate-like

central clamping flanges

51 and 52 surrounding the outer peripheral sides of the

outer cases

5 and 21. The catalyst outer case 5 and the filter outer case 21 are detachably connected by fastening the

center clamping flanges

51 and 52 with the bolts 27 and the nuts 28 and clamping the joining

flanges

25 and 26.

As shown in FIGS. 1 and 12, the upstream end of the filter outer case 21 is connected to the downstream end of the catalyst outer case 5 through the

center clamping flanges

51 and 52 and the

joint flanges

25 and 26. Then, a catalyst downstream space 29 is formed between the diesel oxidation catalyst 2 and the soot filter 3. That is, the downstream end of the diesel oxidation catalyst 2 and the upstream end of the soot filter 3 (filter inner case 20) face each other with a distance L2 for sensor attachment.

As shown in FIGS. 1 and 9, the cylindrical length L4 of the catalyst outer case 5 in the exhaust gas movement direction is longer than the cylindrical length L3 of the upstream cylinder portion 4a of the catalyst inner case 4 in the exhaust gas movement direction. To do. The cylindrical length L6 of the filter outer case 21 in the exhaust gas movement direction is shorter than the cylindrical length L5 of the filter inner case 20 in the exhaust gas movement direction. A length (L2 + L3 + L5) obtained by adding the sensor mounting interval L2 in the catalyst downstream space 29, the cylinder length L3 of the upstream cylinder portion 4a of the catalyst inner case 4 and the cylinder length L5 of the filter inner case 20 is It is configured to be substantially equal to a length (L4 + L6) obtained by adding the cylindrical length L4 of the catalyst outer case 5 and the cylindrical length L6 of the filter outer case 21.

Also, the upstream end of the filter inner case 20 protrudes from the upstream end of the filter outer case 21 by a difference in length between the cases 20 and 21 (L7≈L5−L6). Therefore, in a state in which the filter outer case 21 is connected to the catalyst outer case 5, the upstream side dimension L 7 of the filter inner case 20 protruding from the filter outer case 21 is the downstream side of the catalyst outer case 5 (the downstream side of the catalyst inner case 4). The upstream end of the filter inner case 20 is inserted into the cylindrical part 4b). That is, the upstream side of the filter inner case 20 is inserted into the downstream side cylinder portion 4b (catalyst downstream side space 29) so as to be extractable.

With the above configuration, nitrogen dioxide (NO ₂ ) generated by the oxidation action of the diesel oxidation catalyst 2 is supplied into the soot filter 3 from one side end face (intake side end face) 3a. Particulate matter (PM) contained in the exhaust gas of the diesel engine 70 is collected by the soot filter 3 and continuously oxidized and removed by nitrogen dioxide (NO ₂ ). In addition to the removal of particulate matter (PM) in the exhaust gas of the diesel engine 70, the content of carbon monoxide (CO) and hydrocarbon (HC) in the exhaust gas of the diesel engine 70 is reduced.

As shown in FIGS. 1, 8, and 9, the silencer 30 for attenuating exhaust gas noise discharged from the diesel engine 70 is made of a heat-resistant metal material and is made of a substantially cylindrical silencer inner case 31 and made of a heat-resistant metal material. A cylindrical silencer outer case 32 and a disk-like side lid 33 fixed to the downstream side end of the silencer outer case 32 by welding. A silencer inner case 31 is provided in the silencer outer case 32. The muffler outer case 32 and the catalyst outer case 5 and the filter outer case 21 constitute the DPF casing 60 described above. The diameter of the cylindrical silencer outer case 32 is substantially the same as the diameter of the cylindrical catalyst outer case 5 or the diameter of the cylindrical filter outer case 21.

Disc-shaped

inner lid bodies

36 and 37 are fixed to both ends of the muffler inner case 31 in the exhaust gas movement direction by welding. A pair of exhaust gas introduction pipes 38 is provided between the

inner lid bodies

36 and 37. The upstream end of each exhaust gas introduction pipe 38 passes through the upstream inner lid 36. The downstream end portion of each exhaust gas introduction pipe 38 is closed by a downstream inner lid body 37. A plurality of communication holes 39 are formed in an intermediate portion of each exhaust gas introduction pipe 38. An expansion chamber 45 is communicated with each exhaust gas introduction pipe 38 through a communication hole 39. The expansion chamber 45 is formed inside the silencer inner case 31 (between the inner lids 36 and 37).

An exhaust gas outlet pipe 34 disposed between the exhaust gas introduction pipes 38 is passed through the silencer inner case 31 and the silencer outer case 32. One end side of the exhaust gas outlet pipe 34 is closed by an outlet lid 35. A large number of exhaust holes 46 are formed in the entire exhaust gas outlet pipe 34 inside the silencer inner case 31. Each exhaust gas introduction pipe 38 communicates with the exhaust gas outlet pipe 34 via a plurality of communication holes 39, an expansion chamber 45 and a number of exhaust holes 46. A tail pipe 48 is connected to the other end side of the exhaust gas outlet pipe 34. With the above configuration, the exhaust gas that has entered the both exhaust gas introduction pipes 38 of the silencer inner case 31 passes through the exhaust gas outlet pipe 34 via the plurality of communication holes 39, the expansion chambers 45, and the numerous exhaust holes 46. The sound is discharged out of the silencer 30 through the tail pipe 48.

As shown in FIGS. 1 and 9, the inner diameter side of the thin plate-like ring-shaped filter outlet side joining flange 40 is welded and fixed to the downstream end of the filter inner case 20. The outer diameter side of the filter outlet side joining flange 40 is projected toward the outer peripheral side (radius outside, radial direction) of the filter outer case 21. The downstream end of the filter outer case 21 is fixed by welding to the outer peripheral side of the filter outlet side joining flange 40 (corner corner of the end face L shape). A thin-plate-like silencer-side joining flange 41 that protrudes from the outer peripheral side (radius outside) of the silencer outer case 32 is welded and fixed to the upstream end of the silencer inner case 31. In addition, the upstream side of the silencer inner case 31 is protruded by a predetermined cylindrical dimension L10 on the exhaust gas upstream side of the silencer side joining flange 41. The upstream end of the silencer outer case 32 is fixed by welding to the outer peripheral surface of the silencer inner case 31 on the downstream side of the silencer side joining flange 41.

As shown in FIGS. 1 and 7 to 10, a pair of thick plate-like shapes that butt the filter outlet side joining flange 40 and the muffler side joining flange 41 through the gasket 24 and surround the outer peripheral sides of the

outer cases

21 and 32. The outlet flanges 53 and 54 hold the

joint flanges

40 and 41 from both sides in the exhaust gas movement direction. The filter outer case 21 and the silencer outer case 32 are detachably connected by fastening the

outlet clamping flanges

53 and 54 to the

joint flanges

40 and 41 with bolts 42 and nuts 43, respectively.

As shown in FIG. 1 and FIG. 9, the cylindrical length L9 of the noise reduction outer case 32 in the exhaust gas movement direction is shorter than the cylinder length L8 of the noise reduction inner case 31 in the exhaust gas movement direction. The upstream end of the silencer inner case 31 protrudes from the upstream end (joining flange 41) of the silencer outer case 32 by the difference in length between the cases 31 and 32 (L10≈L8−L9). . In other words, in a state where the silencer outer case 32 is connected to the filter outer case 21, the downstream end (filter outlet side joining flange 40) of the filter outer case 21 is only the dimension L10 where the upstream end of the silencer inner case 31 protrudes. The upstream end portion of the muffler inner case 31 is inserted into the filter downstream space 49 formed inside.

As shown in FIGS. 1 and 7 to 10, the thick plate-like central clamping flange 51 (52) is divided into a plurality (two in the embodiment) in the circumferential direction of the catalyst outer case 5 (filter outer case 21). The

semicircular arc bodies

51a and 51b (52a and 52b) are used. The

semicircular arc bodies

51a and 51b (52a and 52b) of the embodiment are formed in an arc shape (substantially semicircular horseshoe shape). In a state where the filter outer case 21 is connected to the catalyst outer case 5, the respective end portions of the

semicircular arc bodies

51a and 51b (52a and 52b) come into contact with each other. That is, the

semicircular arc members

51a and 51b (52a and 52b) are configured so that the outer peripheral side of the catalyst outer case 5 (filter outer case 21) is annularly surrounded.

The center clamping flange 51 (52) is provided with a plurality of bolt fastening portions 55 with through holes at equal intervals along the circumferential direction. In the embodiment, eight bolt fastening portions 55 are provided on one set of central clamping flanges 51. When viewed in units of the

semicircular arc bodies

51a and 51b (52a and 52b), the bolt fastening portions 55 are provided at four locations at equal intervals along the circumferential direction. On the other hand, bolt holes 56 corresponding to the respective bolt fastening portions 55 of the center clamping flange 51 (52) are formed through the catalyst side joining flange 25 and the filter side joining flange 26.

When connecting the catalyst outer case 5 and the filter outer case 21, the outer peripheral side of the catalyst outer case 5 is surrounded by the catalyst-side semicircular arcs 51 a and 51 b, and the outer peripheral side of the filter outer case 21 is both on the filter side. The catalyst-side joining flange 25 and the filter-side joining flange 26, which are enclosed by the

semicircular arc bodies

52a and 52b and sandwich the gasket 24, are joined from both sides in the exhaust gas movement direction by these semicircular arc bodies (center clamping flanges 51 and 52). Hold it.

In this state, the bolts 27 are inserted into the bolt fastening portions 55 of the

center clamping flanges

51 and 52 on both sides and the bolt holes 56 of the

joint flanges

25 and 26 and tightened with the nuts 28. As a result, the

joint flanges

25 and 26 are sandwiched and fixed by the

center sandwich flanges

51 and 52, and the connection between the catalyst outer case 5 and the filter outer case 21 is completed. Here, the abutting portions of the ends of the catalyst-side

semicircular arcs

51a and 51b and the filter-side

semicircular arcs

52a and 52b are configured to be positioned with a phase shift of 72 °.

As shown in FIGS. 1 and 7 to 10, the thick plate-like outlet clamping flange 53 (54) is divided into a plurality (two in the embodiment) in the circumferential direction of the filter outer case 21 (silencer outer case 32). The

semicircular arc bodies

53a and 53b (54a and 54b) are used. The

semicircular arc bodies

53a, 53b (54a, 54b) of the embodiment have basically the same form as the

semicircular arc bodies

51a, 51b (52a, 52b) of the center clamping flange 51 (52). The outlet clamping flange 53 (54) is also provided with a plurality of bolt fastening portions 57 with through holes at equal intervals along the circumferential direction. On the other hand, bolt holes 58 corresponding to the respective bolt fastening portions 57 of the outlet clamping flange 53 (54) are formed through the filter outlet side joining flange 40 and the silencer side joining flange 41.

When connecting the filter outer case 21 and the silencer outer case 32, the outer periphery side of the filter outer case 21 is surrounded by both

semicircular arcs

53 a and 53 b on the filter outlet side, and the outer periphery side of the silencer outer case 32 is the silencer side. The filter outlet side joining flange 40 and the muffler side joining flange 41, which are surrounded by both the

semicircular arc bodies

54a and 54b and sandwich the gasket 24, are arranged in the exhaust gas movement direction by these semicircular arc bodies (exit sandwiching flanges 53 and 54). Clamp from both sides.

In the above state, the bolts 42 are inserted into the bolt fastening portions 57 of the

outlet clamping flanges

53 and 54 on both sides and the bolt holes 58 of the

joint flanges

40 and 41 and tightened with the nuts 43. As a result, both the joining

flanges

40 and 41 are sandwiched and fixed by the both

outlet sandwiching flanges

53 and 54, and the connection between the filter outer case 21 and the silencer outer case 32 is completed. Here, the abutting portions of the ends of the

semicircular arc bodies

53a and 53b on the filter outlet side and the

semicircular arc bodies

54a and 54b on the silencer side are configured to be positioned with a phase shift of 72 °.

As shown in FIGS. 1 and 7 to 10, at least one of the sandwiching flanges 51 to 54 has a left bracket leg as a support for supporting the DPF casing 60 (

outer cases

5, 21, 32) on the diesel engine 70. 61 is attached. In the embodiment, in one of the semicircular arc bodies 53a of the outlet holding flange 53 on the filter outlet side, the support body fastening portion 59 with a through hole is integrated at two locations so as to be positioned between the adjacent bolt fastening portions 57. Is formed. On the other hand, the left bracket leg 61 is integrally formed with a mounting boss portion 86 corresponding to the support body fastening portion 59 described above.

With the above configuration, the mounting boss portion 86 of the left bracket leg 61 is bolted to the support fastening portion 59 of one semicircular arc member 53a on the filter outlet side, so that the left side of the outlet clamping flange 53 on the filter outlet side The bracket leg 61 is detachably fixed. One end side of the right bracket leg 62 is welded and fixed to the outer peripheral side of the DPF casing 60 (catalyst outer case 5), and the other end sides of the left and

right bracket legs

61 and 62 are DPF formed on the upper surface of the flywheel housing 78. As described above, the bolts are fastened to the attachment portion 80. As a result, the DPF 1 is stably connected and supported on the upper portion of the flywheel housing 78 that is a highly rigid member by the left and

right bracket legs

61 and 62 and the exhaust gas exhaust pipe 103 of the turbine case 101.

As shown in FIGS. 1 and 7 to 10, a gas purifier (diesel oxidation catalyst 2, soot filter 3) for purifying exhaust gas discharged from the engine 70, and each inner side in which the diesel oxidation catalyst 2 and soot filter 3 are built. It has

cases

4, 20, and 31 and

outer cases

5, 21, and 32 that house the

inner cases

4, 20, and 31, respectively. The

inner cases

4, 20, 31 are connected to the

outer cases

5, 21, 32 via

joint flanges

25, 26, 40, 41 that protrude from the outer peripheral side of the

outer cases

5, 21, 32. . The gas purifier (diesel oxidation catalyst 2, soot filter 3), a plurality of combinations of the

inner cases

4, 20, 31 and the

outer cases

5, 21, 32 are provided, and the joining flanges 25, 26 (40, 41) are provided. A plurality of

outer cases

5, 21, 32 are connected by being clamped and fixed by a pair of clamping flanges 51, 52 (53, 54).

Therefore, the adjacent joining flanges 25 and 26 (40 and 41) can be sandwiched from both sides by the sandwiching flanges 51 and 52 (53 and 54) to be pressed (contacted). In addition, since the sandwiching flanges 51 to 54 are formed separately without welding to the

outer cases

5, 21, 32, the stress caused by welding in the relationship between the sandwiching flanges 51 to 54 and the

outer cases

5, 21, 32. There is no risk of concentration or distortion problems. For this reason, a substantially uniform pressure contact force can be applied to the entire joining flanges 25 and 26 (40, 41), and the surface pressure of the sealing surfaces (clamping surfaces) of the clamping flanges 51 to 54 can be maintained high. As a result, it is possible to reliably prevent exhaust gas leakage from between the joint flanges 25 and 26 (40 and 41).

As shown in FIGS. 1 and 7 to 10, each of the holding flanges 51 to 54 is formed of horseshoe-shaped

semicircular arcs

51a, 51b (52a, 52b, 53a) which are divided into a plurality in the circumferential direction of the

outer cases

5, 21, 32. 53b, 54a, 54b), and is configured to surround the outer peripheral side of the

outer cases

5, 21, 32 by a plurality of

semicircular arc members

51a, 51b (52a, 52b, 53a, 53b, 54a, 54b). Yes. Accordingly, the clamping flanges 51 to 54 formed of a plurality of

semicircular arc bodies

51a, 51b (52a, 52b, 53a, 53b, 54a, 54b) are in the same assembled state as that of the integrated object. Therefore, the clamping flanges 51 to 54 can be easily assembled as compared with the ring-shaped one, and the assembling workability can be improved. Moreover, DPF1 with high sealing performance can be comprised, suppressing processing cost and assembly | attachment cost.

Next, the detailed structure of each

joint flange

25, 26, 40 will be described with reference to FIG. Since each of the joining

flanges

25, 26, 40 has basically the same structure, the catalyst side joining flange 25 that is welded and fixed to the catalyst inner case 4 and the catalyst outer case 5 will be described as a representative example. FIG. 11 shows an enlarged side sectional view of the catalyst side joining flange 25 in the embodiment. As shown in FIG. 11, the catalyst-side joining flange 25 has an outer support step portion 25a bent in a step shape in the middle of the L-shaped cross-section end face. The downstream end portion of the catalyst outer case 5 is fitted on the outer support step portion 25 a, and the outer support step portion 25 a is welded and fixed to the downstream end portion of the catalyst outer case 5.

On the other hand, an L-shaped inner diameter side end 25b of the catalyst side joining flange 25 is extended in the extending direction (exhaust gas movement direction) of the catalyst inner case 4 (catalyst outer case 5). The inner diameter side end portion 25 b is fitted on the downstream end portion of the catalyst inner case 4, and the inner diameter side end portion 25 b is welded and fixed to the catalyst inner case 4. On the other hand, an L-shaped outer diameter side end portion 25c of the catalyst side joining flange 25 is extended from the outer periphery of the catalyst outer case 5 in the radial direction (vertical direction). High rigidity of the catalyst side joining flange 25 is ensured by the cross-sectional end face L shape of the catalyst side joining flange 25 and the formation of the outer support step portion 25a.

The clamping

flanges

51, 52 and the joining

flanges

25, 26 are inserted into the clamping

flanges

51, 52 and the joining

flanges

25, 26 through the respective bolt holes 56, and the nuts 28 are screwed together. The outer diameter side end 25c of the catalyst side joining flange 25 is clamped by the clamping

flanges

51 and 52 as described above.

Next, as shown in FIGS. 1 and 12, an upstream gas temperature sensor 109 (downstream gas temperature sensor 112) attached to the DPF 1 will be described. One end of the cylindrical sensor boss body 110 is welded and fixed to the outer peripheral surface of the catalyst inner case 4 between the upstream cylinder portion 4 a and the downstream cylinder portion 4 b of the catalyst inner case 4. From the sensor mounting opening 5a of the catalyst outer case 5, the other end side of the sensor boss body 110 is extended in the radial direction toward the outside of the case 5. A sensor mounting bolt 111 is screwed to the other end side of the sensor boss body 110. For example, a thermistor type upstream gas temperature sensor 109 is passed through the sensor mounting bolt 111, and the upstream gas temperature sensor 109 is supported by the sensor boss body 110 via the sensor mounting bolt 111. A detection portion of the upstream gas temperature sensor 109 is inserted into the catalyst downstream space 29.

With the above configuration, when the exhaust gas is discharged from the gas outflow side end surface 2b of the diesel oxidation catalyst 2, the exhaust gas temperature is detected by the upstream gas temperature sensor 109. In the same manner as described above, as shown in FIG. 1, for example, a thermistor type downstream gas temperature sensor 112 is attached to the sensor boss body 110 via a sensor mounting bolt 111, and the other end face (discharge end face) 3b of the soot filter 3 The downstream gas temperature sensor 112 detects the temperature of the exhaust gas.

Next, the differential pressure sensor 63 attached to the DPF 1 will be described as shown in FIG. The differential pressure sensor 63 is for detecting the pressure difference of the exhaust gas between the upstream side and the downstream side across the soot filter 3 in the DPF 1. Based on the pressure difference, the amount of particulate matter deposited on the soot filter 3 is converted, and the clogged state in the DPF 1 can be grasped. That is, based on the pressure difference of the exhaust gas detected by the differential pressure sensor 63, the regeneration control of the soot filter 3 can be automatically executed by operating an accelerator control means or an intake throttle control means (not shown), for example. It is configured.

The sensor bracket 66 is bolted to the mute-side outlet clamping flange 54 described above, and the sensor bracket 66 is disposed on the upper surface side of the DPF casing 60. A detection main body 67 of the differential pressure sensor 63 is attached to the sensor bracket 66. An upstream pipe joint body 64 and a downstream pipe joint body 65 are connected to a detection main body 67 of the differential pressure sensor 63 via an upstream sensor pipe 68 and a downstream sensor pipe 69, respectively. Similar to the sensor boss body 110, the sensor boss body 113 is disposed in the DPF casing 60. The upstream side pipe joint body 64 (downstream side pipe joint body 65) is fastened to the sensor boss body 113 by the pipe joint bolt 114.

With the above configuration, the difference between the exhaust gas pressure on the inflow side of the soot filter 3 and the exhaust gas pressure on the outflow side of the soot filter 3 (differential pressure of the exhaust gas) is detected via the differential pressure sensor 67. Since the residual amount of particulate matter in the exhaust gas collected by the soot filter 3 is proportional to the differential pressure of the exhaust gas, the difference occurs when the amount of particulate matter remaining in the soot filter 3 increases more than a predetermined amount. Based on the detection result of the pressure sensor 67, regeneration control for reducing the amount of particulate matter in the soot filter 3 (for example, control for increasing the exhaust temperature) is executed. When the residual amount of the particulate matter further increases beyond the regeneration controllable range, the maintenance work for removing and removing the DPF casing 60, cleaning the soot filter 3 and removing the particulate matter artificially is performed.

Next, a second embodiment of the DPF 1 (exhaust gas purification device) according to the present invention will be described with reference to FIG. FIG. 14 is an explanatory cross-sectional view showing the catalyst inner case 4 and the filter inner case 20 of the second embodiment. The catalyst inner case 4 and the filter inner case 20 are formed by a truncated conical steel pipe. The downstream cylindrical portion 4b side (gas discharge side) is formed in a divergent shape with respect to the upstream cylindrical portion 4a (gas intake side) of the catalyst inner case 4. The downstream cylindrical portion 20b side is formed in a divergent shape with respect to the upstream cylindrical portion 20a of the filter inner case 20. That is, the catalyst inner case 4 and the filter inner case 20 are formed in a cylindrical shape whose ridgeline is a straight line. The gas outlet of the catalyst inner case 4 and the gas inlet of the filter inner case 20 are formed to have different diameters.

Further, in the second embodiment of FIG. 14, the downstream gap 23 (space) between the outer peripheral side of the downstream cylindrical portion 4 b of the catalyst inner case 4 and the inner peripheral side of the upstream cylindrical portion 20 a of the filter inner case 20. ) Is formed. A detachable downstream gap 23 is formed between the catalyst inner case 4 and the filter inner case 20 for fitting into a double structure. The catalyst inner case 4 is formed in a large diameter by forming the downstream cylinder part 4b (gas discharge outlet side) of the catalyst inner case 4 and the upstream cylinder part 20a (gas intake inlet side) of the filter inner case 20 to have different diameters. The downstream side cylinder part 4b (gas discharge side) is inserted with the upstream side cylinder part 20a (gas intake side) of the filter inner case 20 formed with a small diameter, and the filter inner case 20 is fitted and connected to the catalyst inner case 4 I am letting. That is, due to the shape of each

case

4, 20, the exhaust gas pressure on the downstream side can be maintained lower than the exhaust gas pressure on the upstream side in each

case

4, 20, and the exhaust resistance can be reduced.

Furthermore, in the second embodiment of FIG. 14, the catalyst outer case 5 is fitted to the catalyst inner case 4 via the catalyst side joining flange 25 as in the first embodiment (FIG. 1). The catalyst outer case 5 (outer case body) is fitted on the outer periphery of the connecting portion between the catalyst inner case 4 and the filter inner case 20. A sensor mounting opening 5a (sensor mounting hole) is formed in the catalyst outer case 5, and a sensor boss body 110 (sensor mounting body) is installed in the catalyst outer case 5 through the sensor mounting opening 5a. The structure is provided with a casing side bracket leg 62 (support bracket) for supporting the catalyst outer case 5, and a notch groove 89 (bolt hole) is formed in the casing side bracket leg 62, and a notch for inserting the front bolt 87 is provided. A notch groove 89 is opened in the side edge of the casing side bracket leg 62.

Next, a third embodiment (modified example of the second embodiment) of the DPF 1 (exhaust gas purification apparatus) of the present invention will be described with reference to FIG. FIG. 15 is a cross-sectional explanatory view showing the catalyst inner case 4 and the filter inner case 20 of the third embodiment. The catalyst inner case 4 and the filter inner case 20 are formed by a truncated conical steel pipe. The downstream cylindrical portion 4b side (gas discharge side) is formed in a tapered shape with respect to the upstream cylindrical portion 4a (gas intake side) of the catalyst inner case 4. The downstream cylindrical portion 20b side is formed in a tapered shape with respect to the upstream cylindrical portion 20a of the filter inner case 20. The downstream cylinder part 4b (gas discharge side) of the catalyst inner case 4 formed with a small diameter is inserted into the upstream cylinder part 20a (gas intake side) of the filter inner case 20 formed with a large diameter, and the filter inner side The catalyst inner case 4 is fitted and connected to the case 20. That is, due to the tapered shape of each case 4, the exhaust gas pressure on the downstream side can be maintained higher than the exhaust gas pressure on the upstream side in each

case

4, 20, and the exhaust gas processing performance can be improved.

Next, a fourth embodiment (modified example of the second embodiment) of the DPF 1 (exhaust gas purification apparatus) of the present invention will be described with reference to FIG. FIG. 16 is a cross-sectional explanatory view showing the catalyst inner case 4 and the filter inner case 20 of the fourth embodiment. The catalyst inner case 4 and the filter inner case 20 are formed by a truncated conical steel pipe. The downstream cylindrical portion 4b side (gas discharge side) is formed in a divergent shape with respect to the upstream cylindrical portion 4a (gas intake side) of the catalyst inner case 4. The downstream cylindrical portion 20b side is formed in a tapered shape with respect to the upstream cylindrical portion 20a of the filter inner case 20. The upstream cylinder portion 20a (gas intake side) of the filter inner case 20 formed in a small diameter is inserted into the downstream cylinder portion 4b (gas discharge side) of the catalyst inner case 4 formed in a large diameter so that the inside of the catalyst. The filter inner case 20 is fitted and connected to the case 4. That is, the exhaust gas pressure on the downstream side can be maintained lower than the exhaust gas pressure on the upstream side in the catalyst inner case 4 due to the divergent shape of the catalyst inner case 4 and the tapered shape of the filter inner case 20, thereby reducing the exhaust resistance. On the other hand, in the filter inner case 20, the exhaust gas pressure on the downstream side can be maintained higher than the exhaust gas pressure on the upstream side, and the exhaust gas processing performance can be improved.

Next, a fifth embodiment (modified example of the second embodiment) of the DPF 1 (exhaust gas purification apparatus) of the present invention will be described with reference to FIG. FIG. 17 is a cross-sectional explanatory view showing the catalyst inner case 4 and the filter inner case 20 of the fifth embodiment. The catalyst inner case 4 is formed by a truncated conical steel pipe. The downstream cylindrical portion 4b side (gas discharge side) is formed in a divergent shape with respect to the upstream cylindrical portion 4a (gas intake side) of the catalyst inner case 4. The filter inner case 20 is formed in a cylindrical shape having the same diameter. The upstream cylinder portion 20a (gas intake side) of the filter inner case 20 formed in a small diameter is inserted into the downstream cylinder portion 4b (gas discharge side) of the catalyst inner case 4 formed in a large diameter so that the inside of the catalyst. The filter inner case 20 is fitted and connected to the case 4. That is, due to the shape of the catalyst inner case 4 spreading toward the end, the exhaust gas pressure on the downstream side can be maintained lower than the exhaust gas pressure on the upstream side in the catalyst inner case 4, and the exhaust resistance can be reduced.

Next, a sixth embodiment (modified example of the second embodiment) of the DPF 1 (exhaust gas purification apparatus) of the present invention will be described with reference to FIG. FIG. 18 is a cross-sectional explanatory view showing the catalyst inner case 4 and the filter inner case 20 of the sixth embodiment. The catalyst inner case 4 is formed by a truncated conical steel pipe. The downstream cylindrical portion 4b side (gas discharge side) is formed in a tapered shape with respect to the upstream cylindrical portion 4a (gas intake side) of the catalyst inner case 4. The filter inner case 20 is formed in a cylindrical shape having the same diameter. The downstream cylinder part 4b (gas discharge side) of the catalyst inner case 4 formed with a small diameter is inserted into the upstream cylinder part 20a (gas intake side) of the filter inner case 20 formed with a large diameter, and the filter inner side The catalyst inner case 4 is fitted and connected to the case 20. That is, due to the tapered shape of the catalyst inner case 4, the exhaust gas pressure on the downstream side can be maintained higher than the exhaust gas pressure on the upstream side in the catalyst inner case 4, and the exhaust gas processing performance can be improved.

Next, a seventh embodiment (modified example of the second embodiment) of the DPF 1 (exhaust gas purification apparatus) of the present invention will be described with reference to FIG. FIG. 19 is a cross-sectional explanatory view showing the catalyst inner case 4 and the filter inner case 20 of the seventh embodiment. The catalyst inner case 4 is formed by a truncated conical steel pipe. The downstream cylindrical portion 4b side (gas discharge side) is formed in a tapered shape with respect to the upstream cylindrical portion 4a (gas intake side) of the catalyst inner case 4. The filter inner case 20 is formed in a cylindrical shape having the same diameter. The upstream cylinder portion 20a (gas intake side) of the filter inner case 20 formed in a small diameter is inserted into the downstream cylinder portion 4b (gas discharge side) of the catalyst inner case 4 formed in a large diameter so that the inside of the catalyst. The filter inner case 20 is fitted and connected to the case 4. That is, due to the tapered shape of the catalyst inner case 4, the exhaust gas pressure on the downstream side can be maintained higher than the exhaust gas pressure on the upstream side in the catalyst inner case 4, and the exhaust gas processing performance can be improved.

Next, an eighth embodiment (modified example of the first embodiment) of the DPF 1 (exhaust gas purification apparatus) of the present invention will be described with reference to FIGS. 20 is an external perspective view showing a joint portion between the catalyst inner case and the filter inner case, FIG. 21 is a sectional explanatory view thereof, FIG. 22 is an enlarged sectional explanatory view thereof, and FIG. 23 is an exploded explanatory view of FIG. is there. Similar to the catalyst-side joining flange 25 of the first embodiment, a thin-plate-shaped catalyst-side joining flange 201 that is welded to the outer periphery of the catalyst inner case 4 (upstream side case) is provided. A catalyst-side joining flange 201 is formed in a donut shape having an L-shaped cross-section. The inner peripheral side of the L-shaped cross-section end face of the catalyst side joining flange 201 is welded and fixed to the end portion of the downstream side cylinder portion 4 b of the catalyst inner case 4. The outer peripheral side of the L-shaped cross-section end face of the catalyst side joining flange 201 is projected toward the outer peripheral side (radial direction) of the catalyst outer case 5 (upstream side case). An outer support step 201a is formed at the bent middle portion of the L-shaped end face of the catalyst side joining flange 201. The downstream end of the catalyst outer case 5 is fixed to the outer support step 201a by welding.

On the other hand, as shown in FIGS. 22 and 23, a filter-side joining flange 202 having a thin plate-like ring shape and a trapezoidal cross section is provided on the gas intake side of the filter outer case 21 (downstream side case). A filter-side joining flange 202 having a trapezoidal cross-sectional end surface is integrally formed at the gas intake side end of the filter outer case 21 by pressing. Further, by the press working, the trapezoidal side end portion 202a of the flange 202 opposite to the trapezoidal end portion of the flange 202 on the downstream side of the filter outer case 21, in other words, the filter outer case 21 (filter side joining flange 202). The diameter of the gas intake side end is reduced to a small diameter. That is, the trapezoidal side end portion 202a of the filter outer case 21 (filter side joining flange 202) is welded and fixed to the middle portion of the filter inner case 20 (downstream side case) in the exhaust gas movement direction.

Furthermore, as shown in FIGS. 22 and 23, the outer peripheral side end 201b of the L-shaped cross-section end face of the catalyst side joining flange 201 is diverging in a shape along the upstream slope 202b on one side of the trapezoidal shape of the filter side joining flange 202. Inclined to form. Further, a joining support step portion 202 c is formed on the inclined lower end side of the upstream slope 202 b of the filter side joining flange 202. The outer peripheral side end 201b of the catalyst side joining flange 201 is brought into the upstream side slope 202b of the filter side joining flange 202 by the guide of the flat inner peripheral surface 201c in the middle of the L-shaped section of the catalyst side joining flange 201 and the joining support step 202c. The catalyst side joining flange 201 is combined with the filter side joining flange 202 by abutting.

22 and FIG. 23, a sandwiching body 203 is provided to be fitted to the catalyst-side joining flange 201 and the filter-side joining flange 202 in the combined state. The sandwiching body 203 is formed in a thin plate-like C-ring shape having a split groove 203a and having a trapezoidal cross-sectional end surface (see FIG. 23). The outer peripheral side end portion 201b of the catalyst side joining flange 201 is brought into contact with the upstream inclined surface 202b of the filter side joining flange 202 via the joining packing 204, and the sandwiching body 203 is placed on the outer peripheral side of each

flange

201, 202. The

flanges

201 and 202 are connected to each other (see FIG. 22).

As shown in FIGS. 20 and 21, a fastening band body 205 is provided for fastening a clamping body 203 fitted to the outer peripheral side of each

flange

201 and 202. The proximal end side of the tightening bolt 207 is locked to the one end side bent portion 205 a of the tightening band body 205 via the connecting shaft body 206. A receiving cylinder 208 that penetrates the distal end side of the tightening bolt 207 is provided. One end portion of the receiving cylinder body 208 is locked to the other end side bent portion 205 b of the tightening band body 205 via the connecting shaft body 209. A tightening nut 210 is screwed onto the distal end side of the tightening bolt 207 that passes through the receiving cylinder 208, and the tightening band body 205 is tensioned by the tightening bolt 207 and the tightening nut 210.

As shown in FIGS. 20 to 23, the gas discharge side of the upstream case (catalyst inner case 4 and catalyst outer case 5) provided with the upstream gas purification body (diesel oxidation catalyst 2) and the downstream gas purification body (soot). Joining flanges (catalyst side joining flange 201, filter side joining flange 202) are respectively formed on the gas intake side of the downstream case (filter inner case 20, filter outer case 21) in which the filter 3) is provided. A sandwiching body 203 is detachably fitted to each joining

flange

201, 202 of each

case

4, 5, 20, 21. The clamping body 203 forming a V-shaped clamp is detachably fastened by a fastening band body 205.

The gas intake side of the downstream case (filter inner case 20, filter outer case 21) is separated from the gas discharge side of the upstream case (catalyst inner case 4, catalyst outer case 5), and the downstream gas purifier (soot). In order to improve the maintainability of the filter 3), a sandwiching body 203 having a V-shaped clamp structure is used as the sandwiching body 203 for connecting the joining

flanges

201 and 202 of the

cases

4, 5, 20, and 21. In this case, there is a problem that the manufacturing cost cannot be easily reduced by forming the V-shaped clamp structure of the sandwiching body 203 by cutting a thick plate made of stainless steel. The production cost can be reduced by not using a stainless steel plate, but there is a problem that rust easily occurs. Further, when the V-shaped clamp structure of the sandwiching body 203 is formed of a thin plate made of stainless steel, welding strain or welding is fixed by fixing the sandwiching body 203 to the downstream case (filter outer case 21) by welding. There is a problem that it is not possible to secure the optimum mountability and sealability by sputtering. When the clamp body 203 is fixed to the downstream case (filter outer case 21) by welding, it is necessary to increase the mounting diameter of the clamp body 203 having the V-shaped clamp structure in order to avoid the height of the weld leg. There is a problem that the compactness characteristic of the V-shaped clamp structure cannot be exhibited.

On the other hand, in the structure of the eighth embodiment shown in FIGS. 20 to 23, the downstream case (filter outer case 21) and the clamp body 203 of the V-shaped clamp structure are integrated, so the number of components Can be reduced, the number of welded parts can be reduced, and the structure can be reduced. Since it is not necessary to weld the sandwiching body 203 in the vicinity of the

joint flanges

201 and 202 of the

cases

4, 5, 20, and 21, it is possible to easily secure the mounting property and the sealing property. By loosening the fastening of the sandwiching body 203 having the V-shaped clamp structure, the downstream case (the filter inner case 20 and the filter outer case 21) can be separated, and the maintainability of the soot filter 3 and the like can be improved. Compared to the bolted flange structure, the outermost diameter of the fastening portion of the clamp body 203 having the V-shaped clamp structure can be formed smaller, and the outer shape of the DPF 1 can be formed compactly. All the components such as the sandwiching body 203 and the fastening band body 205 can be made of stainless steel, and additional rust countermeasures (rust prevention coating, etc.) are unnecessary. The product value can be further increased by installing the sandwiching body 203 having a V-shaped clamp structure excellent in sealing performance and maintenance performance on the DPF 1.

20 to 23, the filter inner case 20 is inserted into the catalyst inner case 4, but the shape of the catalyst side joining flange 201 and the shape of the filter side joining flange 202 may be interchanged. That is, the catalyst inner case 4 is configured to be inserted into the filter inner case 20, the catalyst-side joining flange 201 is formed in a thin ring shape with a trapezoidal cross-sectional end surface, and the cross-sectional end surface is an L-shaped donut shape. The clamping body 203 can be easily fixed to the catalyst side joining flange 201 formed on the gas discharge side of the upstream case (catalyst inner case 4 and catalyst outer case 5) by the fastening band body 205. Needless to say, what you can do.

As shown in FIGS. 1 and 14 to 19, a diesel oxidation catalyst 2 (upstream gas purification body) that purifies exhaust gas discharged from the diesel engine 70 and a soot filter 3 that purifies exhaust gas discharged from the diesel engine 70. (Downstream gas purification body), catalyst inner case 4 (upstream gas purification body case) in which the diesel oxidation catalyst 2 is installed, and filter inner case 20 (downstream gas purification body case) in which the soot filter 3 is installed. In the DPF 1 (exhaust gas purifying device) in which the gas discharge side of the catalyst inner case 4 and the gas intake side of the filter inner case 20 are fitted and connected, the catalyst inner case 4 is formed in a cylindrical shape having the same diameter, The filter inner case 20 is formed in a cylindrical shape having the same diameter. That is, the catalyst inner case 4 and the filter inner case 20 are formed in a cylindrical shape having the same diameter on the exhaust gas intake side and the exhaust side. One of the catalyst inner case 4 and the filter inner case 20 (gas purifier case) is formed to have a smaller diameter than the other.

Therefore, compared with the prior art which provided the enlarged diameter part in any one of the catalyst inner case 4 and the filter inner case 20 formed with the cylindrical body of the same diameter, the enlarged diameter part is provided in the catalyst inner case 4 or the filter inner case 20. Since the catalyst inner case 4 or the filter inner case 20 can be formed in a cylindrical shape having a straight ridgeline, it is not necessary to provide the catalyst inner case 4 or the filter inner case 20 with a diameter-enlarged portion. The processing cost of the case 4 or the filter inner case 20 can be reduced. Moreover, there is no need to provide a step between the exhaust gas exhaust side of the catalyst inner case 4 and the exhaust gas intake side of the filter inner case 20 to form an enlarged diameter portion, which is caused by repeated thermal expansion and contraction. Thus, it is possible to reduce the local concentration of thermal stress on a specific portion of the catalyst inner case 4 or the filter inner case 20, and to improve the durability of the catalyst inner case 4 or the filter inner case 20 (gas purifier case).

As shown in FIGS. 1 and 14 to 19, a diesel oxidation catalyst 2 for purifying exhaust gas discharged from the diesel engine 70, a soot filter 3 for purifying exhaust gas discharged from the diesel engine 70, and a diesel oxidation catalyst 2 are provided. In the DPF 1 that includes a catalyst inner case 4 to be installed inside and a filter inner case 20 to install the soot filter 3, and fits and connects the gas discharge side of the catalyst inner case 4 and the gas intake side of the filter inner case 20, The catalyst inner case 4 is formed in a cylindrical shape with a ridge line, and the filter inner case 20 is formed in a cylindrical shape with a ridge line. That is, the catalyst inner case 4 (upstream gas purification body case) and the filter inner case 20 (downstream gas purification body case) are formed in a cylindrical shape in which ridgelines of their outer diameters are straight without a step. The gas outlet of the catalyst inner case 4 and the gas inlet of the filter inner case 20 are formed to have different diameters.

Therefore, compared with the prior art, it is not necessary to provide a diameter-enlarged portion in the catalyst inner case 4 or the filter inner case 20, so that the process of providing the diameter-enlarged portion in the catalyst inner case 4 or the filter inner case 20 is not required. The processing cost of the case 4 or the filter inner case 20 can be reduced. Moreover, there is no need to provide a step between the exhaust gas exhaust side of the catalyst inner case 4 and the exhaust gas intake side of the filter inner case 20 to form an enlarged diameter portion, which is caused by repeated thermal expansion and contraction. Thus, it is possible to reduce the local concentration of thermal stress on a specific part of the catalyst inner case 4 or the filter inner case 20, and to improve the durability of the catalyst inner case 4 or the filter inner case 20.

As shown in FIGS. 1 to 13, either the catalyst inner case 4 or the filter inner case 20 is formed to have a larger diameter than the other, and the gas outlet side (or the filter inner case 20) of the catalyst inner case 4 on the larger diameter side is formed. The gas intake side of the small-diameter filter inner case 20 (or the gas discharge side of the catalyst inner case 4) is inserted into the gas intake side). Therefore, the gas intake side of the filter inner case 20 can be easily put in and out of the gas discharge side of the large catalyst inner case 4. The assembling / disassembling workability of the filter inner case 20 can be improved.

As shown in FIGS. 1, 14, 16, 17, and 19, the filter inner case 20 is formed to have a smaller diameter than the catalyst inner case 4, and the gas inner side of the larger catalyst inner case 4 has a smaller diameter side. The gas intake side of the filter inner case 20 is inserted. Therefore, the processing cost of the catalyst inner case 4 or the filter inner case 20 can be reduced as compared with the prior art, and thermal stress is applied to a specific part of the catalyst inner case 4 or the filter inner case 20 due to repeated thermal expansion and contraction. Can be reduced, and the durability of the catalyst inner case 4 or the filter inner case 20 can be improved. Since the catalyst side joining flange 25 and the filter side joining flange 26 for connecting the catalyst inner case 4 and the filter inner case 20 can be arranged at the outer peripheral position of the filter inner case 20, Assembling / disassembling workability on the filter inner case 20 side having a gas outlet pipe (silencer 30) and the like can be improved.

As shown in FIGS. 15 and 18, the catalyst inner case 4 is formed with a smaller diameter than the filter inner case 20, and the gas outlet side of the larger catalyst inner case 4 is disposed on the gas intake side of the filter inner case 20 on the smaller diameter side. Is configured to be inserted. Therefore, the processing cost of the catalyst inner case 4 or the filter inner case 20 can be reduced as compared with the prior art, and thermal stress is applied to a specific part of the catalyst inner case 4 or the filter inner case 20 due to repeated thermal expansion and contraction. Can be reduced, and the durability of the catalyst inner case 4 or the filter inner case 20 can be improved. Since the catalyst side joining flange 25 and the filter side joining flange 26 for connecting the catalyst inner case 4 and the filter inner case 20 can be arranged at the outer peripheral position of the catalyst inner case 4, Assembling / disassembling workability on the catalyst inner case 4 side having a gas inlet pipe and the like can be improved.

As shown in FIGS. 1 and 14 to 19, the gas discharge side of the catalyst inner case 4 and the gas intake side of the filter inner case 20 are formed to have different diameters, and the gas discharge side of the catalyst inner case 4 and the filter inner case 20 The gas intake side is fitted and connected. Accordingly, the gas intake side and the gas discharge side of the catalyst inner case 4 (or the filter inner case 20) are formed to have the same diameter, or the catalyst inner case 4 (or the filter inner case 20 is formed into a truncated cone shape with a straight ridge line. ), The processing cost of the catalyst inner case 4 (or the filter inner case 20) can be reduced as compared with the prior art, and the catalyst inner case 4 or the filter inner case 20 is caused by repeated thermal expansion and contraction. It is possible to reduce the local concentration of thermal stress on the specific part of the catalyst and to improve the durability of the catalyst inner case 4 or the filter inner case 20. In the case of the catalyst inner case 4 (or filter inner case 20) having the same diameter on the gas intake side and gas discharge side, the catalyst inner case 4 (or filter inner case 20) can be easily formed by cutting the long pipe. . When the catalyst inner case 4 (or the filter inner case 20) is in the shape of a truncated cone, the assembly / disassembly workability such as the fitting / extraction operation on the gas discharge side of the catalyst inner case 4 and the gas intake side of the filter inner case 20 is improved. it can.

As shown in FIGS. 1 and 14 to 19, the catalyst outer case 5 or the filter outer case 21 (outer case body) is fitted on the outer periphery of the connecting portion between the catalyst inner case 4 and the filter inner case 20. Therefore, the catalyst inner case 4 and the filter inner case 20 can be protected, and the temperature drop in the catalyst inner case 4 and the filter inner case 20 can be reduced. The casing side bracket leg 62 (support bracket) can be installed on the catalyst outer case 5 or the flange side bracket leg 61 (support bracket) can be installed on the filter outer case 21 with high rigidity, so that the support strength of the DPF 1 can be improved.

As shown in FIGS. 1 and 14 to 19, a downstream gap 23 (detachment gap) for fitting into a double structure is formed between the catalyst inner case 4 and the filter inner case 20. Therefore, the catalyst inner case 4 and the filter inner case 20 can be attached and detached with a simple operation. That is, for example, when the catalyst inner case 4 and the filter inner case 20 are brought into close contact with each other in order to prevent the exhaust gas from leaking from the connection portion between the catalyst inner case 4 and the filter inner case 20, Case 4 and filter inner case 20 were integrated by rust or the like, and catalyst inner case 4 and filter inner case 20 could not be easily separated. Compared to the conventional case, the catalyst inner case 4 and the filter inner case 20 can be easily separated, and the maintenance and replacement workability of the catalyst inner case 4 or the filter inner case 20 can be improved.

As shown in FIGS. 1 and 14 to 19, a sensor attachment opening 5a (sensor attachment hole) is formed in the catalyst outer case 5 or the filter outer case 21, and the catalyst outer case 5 or the filter outer case is formed through the sensor attachment opening 5a. Since the sensor boss body 110 (sensor mounting body) is installed at 21, the temperature drop in the catalyst outer case 5 or the filter outer case 21 can be reduced. The gas purification function of the diesel oxidation catalyst 2 or the soot filter 3 can be maintained continuously by maintaining the gas temperature of the diesel oxidation catalyst 2 or the soot filter 3 at or above a predetermined temperature (self-regeneration temperature at which soot automatically disappears). In addition, the upstream gas temperature sensor 109 (exhaust gas sensor) can be assembled through the sensor boss body 110 so as to approach the end surface of the diesel oxidation catalyst 2 in the catalyst inner case 4. The detection accuracy of the exhaust gas by the upstream gas temperature sensor 109 can be easily improved.

As shown in FIGS. 1 and 14 to 19, the structure includes a casing side bracket leg 62 for supporting the catalyst outer case 5, and a notch hole 89 (bolt hole) is formed in the casing side bracket leg 62 to insert a bolt. A notch hole 89 is formed in the side edge of the casing side bracket leg 62 through a notch for use. Therefore, after attaching the temporary fixing bolt 87 (bolt) for temporary fixing to the attachment site on the diesel engine 70 side or the machine side to which the casing side bracket leg 62 is connected in a semi-fixed state, The notch hole 89 can be engaged via the DPF 1 to support the DPF 1 at the attachment site. That is, the operator can fasten the flange-side bracket leg 61 and the casing-side bracket leg 62 by tightening the rear bolt 88 (bolt) in a state where the hand is released from the DPF 1. A single worker can attach and detach the DPF. The assembly workability of the entire DPF 1 (catalyst outer case 5 and filter outer case 21), which is a heavy object, can be improved.

As shown in FIG. 1 and FIG. 20 to FIG. 23, the gas discharge side of the upstream case (catalyst inner case 4 and catalyst outer case 5) provided with the upstream gas purification body (diesel oxidation catalyst 2), and the downstream gas Joining flanges (catalyst side joining flange 201, filter side joining flange 202) are respectively formed on the gas intake side of the downstream case (filter inner case 20, filter outer case 21) where the purifier (soot filter 3) is provided, The sandwiching body 203 is detachably fitted to the

joint flanges

201 and 202 of the

cases

4, 5, 20, and 21, and the sandwiching body 203 is detachably fastened by the fastening band body 205. ing.

Therefore, the clamping body 203 can be easily attached / detached by the attaching / detaching operation of the tightening band body 205, and the gas in the filter inner case 20 and the filter outer case 21 with respect to the gas discharge side of the catalyst inner case 4 and the catalyst outer case 5. The intake side can be easily separated or joined. For example, even if the installation location of the DPF housing 60 is a narrow space (inside the engine room, etc.), particulate matter accumulated in the soot filter 3 can be removed by a simple attaching / detaching operation, and the inside of the filter inner case 20 is cleaned. Maintenance workability such as can be improved.

1 DPF (diesel particulate filter)
2 Diesel oxidation catalyst (gas purifier)
3 Soot filter (gas purifier)
4 Catalyst inner case (upstream case)
4a Upstream cylinder part 4b of catalyst inner case Downstream cylinder part 5 of catalyst inner case 5 Catalyst outer case (outer case body, upstream case)
5a Sensor mounting opening (sensor mounting hole)
20 Filter inner case (downstream case)
20a Upstream tube portion 20b of filter inner case Downstream tube portion 21 of filter inner case 21 Filter outer case (outer case body, downstream case)
62 Casing side bracket leg (support bracket)
70 Diesel Engine 87 Tip Bolt 89 Notch Groove (Bolt Hole)
110 Sensor boss body (sensor mounting body)
201 catalyst side joining flange 202 filter side joining flange 203 clamping body 205 tightening band body

Claims

An upstream gas purification body for purifying exhaust gas discharged from the engine, a downstream gas purification body for purifying exhaust gas discharged from the engine, and an upstream gas purification body case in which the upstream gas purification body is provided. A downstream gas purification body case in which the downstream gas purification body is installed, and a gas discharge side of the upstream gas purification body case and a gas intake side of the downstream gas purification body case are fitted and connected. In the exhaust gas purification device,
The upstream gas purification body case and the downstream gas purification body case are formed in a cylindrical shape having the same diameter on the exhaust gas intake side and the exhaust side, and the upstream gas purification body case or the downstream gas purification body An exhaust gas purifying apparatus characterized in that one of the cases is formed to have a smaller diameter than the other.
An upstream gas purification body for purifying exhaust gas discharged from the engine, a downstream gas purification body for purifying exhaust gas discharged from the engine, and an upstream gas purification body case in which the upstream gas purification body is provided. A downstream gas purification body case in which the downstream gas purification body is installed, and a gas discharge side of the upstream gas purification body case and a gas intake side of the downstream gas purification body case are fitted and connected. In the exhaust gas purification device,
The upstream gas purification body case and the downstream gas purification body case are formed in a cylindrical shape in which the ridge line of the outer diameter thereof is a straight line without a step, and the gas outlet of the upstream gas purification body case and the An exhaust gas purification apparatus characterized in that the gas inlets of the downstream gas purification body case have different diameters.
Either the upstream gas purification body case or the downstream gas purification body case is formed with a larger diameter than the other, and the gas discharge side (or the downstream gas) of the upstream gas purification body case on the large diameter side The gas intake side (or the gas discharge side of the upstream gas purification body case) of the downstream gas purification body case on the small diameter side is inserted into the gas intake side of the purification body case). The exhaust gas purification apparatus according to claim 1 or 2.
The downstream gas purification body case is formed with a smaller diameter than the upstream gas purification body case, and the downstream gas purification body case on the small diameter side is disposed on the gas discharge side of the upstream gas purification body case on the large diameter side. The exhaust gas purification device according to claim 1 or 2, wherein the exhaust gas purification device is configured to insert a gas intake side.
The upstream gas purification body case is formed with a smaller diameter than the downstream gas purification body case, and the upstream side gas purification body case on the large diameter side is disposed on the gas intake side of the downstream gas purification body case on the small diameter side. The exhaust gas purification device according to claim 1 or 2, wherein the exhaust gas purification device is configured to insert a gas discharge side.
The gas discharge side of the upstream gas purification body case and the gas intake side of the downstream gas purification body case are formed with different diameters, and the gas discharge side of the upstream gas purification body case and the gas intake side of the downstream gas purification body case are formed The exhaust gas purification device according to claim 1 or 2, wherein the exhaust gas purification device is configured to be fitted and connected.
The exhaust gas purification device according to claim 1 or 2, wherein an outer case body is fitted on an outer periphery of a connecting portion between the upstream gas purification body case and the downstream gas purification body case.
The exhaust gas purifying device according to claim 6, wherein an attachment / detachment gap for fitting into a double structure is formed between the upstream gas purification body case and the downstream gas purification body case.
Bonding flanges are respectively formed on the gas discharge side of the upstream case where the upstream gas purification body is provided and the gas intake side of the downstream case where the downstream gas purification body is provided. The exhaust gas purification device according to claim 1 or 2, wherein the sandwiching body is detachably fitted and the sandwiching body is detachably fastened by a tightening band body.