JP2003056336A - Exhaust emission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a whole length of a casing by using in common a connecting margin of pipes for introducing exhaust gas into a first space and a second space along an axial direction of the casing. SOLUTION: A first ventilating type purification member 2 and a second ventilating type purification member 3 are provided in series in the common casing 1. A mutual space between the ventilating type purification members 2 and 3 are partitioned into the first space 4 and the second space 5 by a partition plate 6. The exhaust gas 8 introduced into the first space 4 passes the ventilating type purification member 2 and is introduced into the second space 5, and then the exhaust gas 8 passes the ventilating type purification member 3. The partition plate 6 is bent in a shape of S so as to obliquely extend from a position near the ventilating type purification member 2 side to a position near the ventilating type purification member 3 side. The connecting margins of the pipes 7 and 10 for introducing the exhaust gas 8 into the first space 4 and the second space 5 are secured at an almost same position along the axial position of the casing 1.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for purifying exhaust gas by passing the same through the exhaust gas. 2. Description of the Related Art Conventionally, a ventilation type purifying material such as a catalytic converter or a particulate filter is provided in the middle of an exhaust pipe through which exhaust gas from an engine flows, and is passed through the ventilation type purifying material. Purification of exhaust gas has been performed. [0003] Here, as a catalytic converter, a NOx reduction catalyst (selective reduction catalyst) having a property of selectively reacting NOx with a reducing agent even in the presence of oxygen, or a lean-burn catalyst having a high oxygen concentration in exhaust gas is used. During operation, NOx is oxidized and temporarily stored in the form of nitrate, and NOx is decomposed and released by the presence of hydrocarbons and carbon monoxide in the exhaust gas during operation at a rich air-fuel ratio where the oxygen concentration in the exhaust gas is low. There are known a NOx storage reduction catalyst having a purifying property, an oxidation catalyst which assists in oxidizing and purifying particulates (particulate matter) contained in exhaust gas, and the like. [0004] The particulate filter physically collects particulates, has a porous honeycomb structure made of ceramic such as cordierite or the like, and has a flow path formed in a lattice-like shape. The inlets are alternately plugged, and the outlets of the passages whose inlets are not plugged are sealed so that only the exhaust gas that has passed through the porous thin wall that defines each passage is sealed. The exhaust gas is discharged to the downstream side, and the particulates in the exhaust gas are collected on the inner surface of the porous thin wall. Some particulate filters of this type are provided with one of the above-mentioned catalytic converters integrally, so that a composite exhaust gas purifying action can be obtained. [0006] In recent years, exhaust gas purification regulations have been very strictly tightened. Therefore, these ventilation converters, such as catalytic converters and particulate filters, are connected in series in a common casing in the exhaust pipe. The adoption of an exhaust gas purification device having two units installed to enhance exhaust gas purification capability is being studied. However, an exhaust gas purification apparatus in which a first ventilation type purifying material and a second ventilation type purifying material are connected in series in a common casing has a length dimension in the axial direction of the casing. For example, in vehicles with a short wheelbase in which various accessories are already laid out in a tight condition, it is necessary to secure the mounting space for the exhaust purification device while avoiding interference with the accessories. Has become very difficult, and there have been cases where the piping for guiding exhaust gas from the engine must be connected to the middle part in the axial direction of the casing from a direction substantially perpendicular to the casing due to layout restrictions. In such a case, as shown in FIG. 4, a first ventilation type purifying material 2 and a second ventilation type purifying material 3 connected in series in a common casing 1 Is divided by a partition plate 6 into a first space 4 facing the ventilated purifying material 2 and a second space 5 facing the second ventilated purifying material 3, and introduced into the first space 4 via a pipe 7. The exhaust gas 8 passed through the first ventilation type purifying material 2 is extracted into a third space 9 on one end side of the casing 1, and the exhaust gas 8 is transferred from the third space 9 to the second space 5 via a pipe 10. The exhaust gas 8 drawn into the fourth space 11 at the other end of the casing 1 must be guided to pass through the second ventilation type purifying material 3 and discharged to the pipe 12 on the downstream side. However, in such a conventional structure, the connection allowance of the pipe 7 leading to the first space 4 and the connection allowance of the pipe 10 leading to the second space 5 are made of the casing 1. Since they are individually secured in the axial direction, the total length of the casing 1 is increased due to the connection allowances for these two parts, which deteriorates the mountability to the vehicle. [0010] The present invention has been made in view of the above-mentioned circumstances, and the connection allowance of the exhaust gas introduction pipe to each of the first space and the second space is shared in the axial direction of the casing to reduce the total length of the casing. It is an object of the present invention to provide an exhaust gas purification device that can be shortened and has good mountability to a vehicle. According to the present invention, a first ventilation type purifying material and a second ventilation type purifying material are connected in series in a common casing, and the two ventilation type purifying materials are mutually connected. The partition is divided into a first space facing the first ventilation type purifying material side and a second space facing the second ventilation type purification material side by a partition plate, and the exhaust gas introduced into the first space is subjected to the first ventilation. An exhaust purification device configured to pass through the second purifying material, pass through the second purifying material, and then pass through the second ventilating purifying material to the second space, wherein the partition plate is positioned closer to the first ventilating purifying material side. From the side to the second ventilation-type purifying material side, bent and arranged in a substantially S-shape so as to extend diagonally, and the connection margin of the exhaust gas introduction pipe to each of the first space and the second space is determined by the axial center of the casing. It is characterized by being secured at substantially the same position in the direction. [0012] According to this structure, the connection margin of the exhaust gas introduction pipe to each of the first space and the second space is secured at substantially the same position in the axial direction of the casing. The connection allowance is shared in the axial direction of the casing, and the connection allowance for each pipe, which must be secured in the axial direction of the casing, can be reduced to one, so that the overall length of the casing can be reduced as compared with the conventional case. It becomes possible. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
The portions denoted by the same reference numerals as those in FIG. 4 represent the same items. As shown in FIG. 1, in the exhaust gas purifying apparatus of this embodiment, the exhaust gas purifying apparatus shown in FIG.
A first ventilation type purifying material 2 and a second ventilation type purifying material 3 are connected in series in a common casing 1 to form a double ventilation type purifying material 2.
3 are divided by a partition plate 6 into a first space 4 facing the first ventilated purifying material 2 side and a second space 5 facing the second ventilated purifying material 3 side. The exhaust gas 8 introduced through the pipe 7 is passed through the first ventilation type purifying material 2, and then guided to the second space 5 by the pipe 10 so that the second ventilation type purifying material 3 is formed.
The partition plate 6 is formed in a substantially S-shape so as to diagonally cross the partition plate 6 from a position closer to the first ventilated purifying material 2 to a position closer to the second ventilated purifying material 3. So that the connection allowance of the pipes 7 and 10 to each of the first space 4 and the second space 5 is secured at substantially the same position in the axial direction of the casing 1 (the left-right direction in FIG. 1). I have. In this manner, the connection allowance of the pipes 7 and 10 for introducing the exhaust gas 8 into each of the first space 4 and the second space 5 is substantially reduced in the axial direction of the casing 1. By ensuring the same position, each of the pipes 7, 1
0 is shared in the axial direction of the casing 1, and only one connection margin for each of the pipes 7 and 10 that must be secured in the axial direction of the casing 1 suffices. Can be reduced to a size obtained by subtracting Δl corresponding to one connection allowance between the pipes 7 and 10 from the conventional length L (see FIG. 4). Therefore, according to the above embodiment, the first space 4
In addition, the connection allowance of the pipes 7 and 10 for introducing the exhaust gas 8 into each of the second space 5 can be shared in the axial direction of the casing 1 so that the entire length of the casing 1 can be shortened. The mountability can be greatly improved as compared with the conventional case. Also, as shown in FIG. 1, a pipe 7 leading to the first space 4 and a pipe 10 leading to the second space 5
When the partition plate 6 is disposed so as to be inclined in the facing direction, the inclined surface of the partition plate 6 allows the flow of the exhaust gas 8 toward each of the ventilation purifying materials 2 and 3. An ancillary effect of smoothly promoting the conversion and rectifying the exhaust gas 8 can also be expected. FIG. 2 shows a second embodiment of the present invention.
In the present embodiment, the pipe 10 for guiding the exhaust gas 8 from the third space 9 to the second space 5 is connected to the center of the end face of the third space 9 from the axial direction of the casing 1. Except for the above, it is the same as the first embodiment of FIG. 1 described above, and it goes without saying that the overall length of the casing 1 itself can be shortened even when applied to such an exhaust gas purification apparatus. FIG. 3 shows a third embodiment of the present invention. In this embodiment, a pipe 7 communicating with the first space 4 is provided.
And a pipe 10 communicating with the second space 5 is connected to the flow path switching valve 1.
When the flow path switching valve 13 is switched from the solid line state to the chain line state in the drawing, the exhaust gas 8 from the engine passes through the flow path switching valve 13 to the third space 9. The exhaust gas 8 introduced in advance to the side and flowing in the reverse direction through the first ventilation type purifying material 2 flows from the first space 4 through the pipe 7, the flow path switching valve 13, and the pipe 10 in the second space. 5. That is, in this embodiment, the flow path switching valve 13
, The flow direction of the exhaust gas 8 with respect to the first ventilation type purifying material 2 can be appropriately reversed. If the flow direction of the exhaust gas 8 is appropriately reversed in this way, for example, When the first ventilation type purifying material 2 is a particulate filter, the trapping of a new particulate by using the back surface of the porous thin wall defining each flow path of the particulate filter as a collecting surface. Collection can be performed, and unburned particulates on the front side surface of the porous thin wall can be removed by backwashing to achieve good regeneration of the collection surface. In the case where a catalyst such as a NOx storage reduction catalyst is integrally supported, the utilization efficiency of the supported catalyst can be improved. Then, in adopting a configuration for reversing the flow direction of the exhaust gas 8 with respect to the first ventilation type purifying material 2 as shown here, the first ventilation type purifying material 2 and the second A first space 4 and a second space 5 are defined between the ventilation material 3 and the pipes 7 and 10 respectively.
Must be connected, and it is very effective to apply the structure of the present invention also when employing such an exhaust emission purification device. It should be noted that the exhaust gas purifying apparatus of the present invention is not limited to the above-described embodiment, but may be variously modified without departing from the gist of the present invention. According to the exhaust gas purifying apparatus of the present invention described above, the margin of connection of the exhaust gas introduction pipe to each of the first space and the second space is shared in the axial direction of the casing, and Since the overall length of the vehicle can be shortened, it is possible to obtain an excellent effect that the mountability on a vehicle can be greatly improved as compared with the related art.

[Brief description of the drawings] FIG. 1 is a schematic view showing a first embodiment of the present invention. FIG. 2 is a schematic view showing a second embodiment of the present invention. FIG. 3 is a schematic view showing a third embodiment of the present invention. FIG. 4 is a schematic view showing a conventional example. [Explanation of symbols] 1 casing 2 The first ventilation type purifying material 3 The second ventilation type purifying material 4 first space 5 Second space 6 Partition plate 7 Piping 8 Exhaust gas 10 Piping

Claims (1)

Claims: 1. A first ventilation type purifying material and a second ventilation type purifying material are connected in series in a common casing, and a partition plate separates the two ventilation type purifying materials from each other. It is divided into a first space facing the first ventilation type purification material side and a second space facing the second ventilation type purification material side, and the exhaust gas introduced into the first space passes through the first ventilation type purification material. An exhaust gas purifying apparatus configured to guide the partition plate to the second space and pass the second ventilation type purifying material, wherein the partition plate is moved from the position near the first ventilation type purifying material to the second ventilation type. It is bent and arranged in a substantially S shape so as to cross diagonally to the position from the side of the purifying material side, and the connection allowance of the exhaust gas introduction pipe to each of the first space and the second space is substantially the same position in the axial direction of the casing. Exhaust gas purifier characterized by having been secured.