JP5252904B2 - Exhaust purification device - Google Patents

Description

  The present invention relates to an exhaust emission control device.

  Particulate matter (particulate matter) discharged from diesel engines is mainly composed of carbonaceous soot and SOF (Soluble Organic Fraction) consisting of high-boiling hydrocarbon components. Furthermore, the composition contains a small amount of sulfate (mist-like sulfuric acid component). As a measure to reduce this type of particulates, a particulate filter is installed in the middle of the exhaust pipe through which the exhaust gas flows. Has been performed conventionally.

  The particulate filter has a porous honeycomb structure made of a ceramic such as cordierite, and the inlets of the respective channels partitioned in a lattice shape are alternately sealed, and the channels are not sealed. The outlet is sealed, and only the exhaust gas that has permeated through the porous thin wall defining each flow path is discharged to the downstream side.

  Then, the particulates in the exhaust gas are collected and deposited on the inner surface of the porous thin wall, so that the particulates are appropriately burned and removed before the exhaust resistance increases due to clogging. It is necessary to regenerate, but in normal diesel engine operation conditions, there are few opportunities to obtain exhaust temperatures that are high enough for particulates to self-combust, so a catalyst regeneration type that integrally supports an oxidation catalyst. Adoption of a particulate filter is being studied.

  That is, if such a catalyst regeneration type particulate filter is employed, the oxidation reaction of the collected particulates is promoted to lower the ignition temperature, and the particulates can be burned and removed even at an exhaust temperature lower than the conventional one. It becomes possible.

  However, even when such a catalyst regeneration type particulate filter is used, the trapped amount exceeds the particulate processing amount in the operation region where the exhaust temperature is low, so such a low exhaust gas. If the operation state at the temperature continues, there is a possibility that the particulate filter will fall into an over trapped state without the regeneration of the particulate filter proceeding well.

  Therefore, a flow-through type oxidation catalyst is separately arranged in front of the particulate filter, and fuel is added to the exhaust gas upstream of the oxidation catalyst at the stage where the amount of particulate accumulation has increased. It is considered to perform forced regeneration.

  That is, the fuel (HC) added on the upstream side of the particulate filter undergoes an oxidation reaction while passing through the preceding oxidation catalyst, and the catalyst bed of the particulate filter immediately after the inflow of exhaust gas heated by the reaction heat. The temperature is raised, the particulates are burned out, and the particulate filter is regenerated.

  As a specific means for executing this kind of fuel addition, post-injection is added at the timing of non-ignition later than the compression top dead center following the main injection of fuel performed near the compression top dead center. What is necessary is just to add a fuel in gas.

  As shown in FIG. 2, when installing such a particulate filter 1 in the middle of the exhaust pipe 3 together with the oxidation catalyst 2 in the previous stage, the front stage is placed in a casing 4 interposed in the middle of the exhaust pipe 3. The oxidation catalyst 2 and the particulate filter 1 are arranged and accommodated in series, and a hanging tool 5 is welded to an appropriate position of the casing 4, and the casing 4 is supported by hanging from the vehicle body 6 side through the hanging tool 5. I am doing so.

In addition, as prior art document information that technically discloses the arrangement state of the oxidation catalyst 2 and the particulate filter 1 in the preceding stage, there is, for example, the following Patent Document 1 by the same applicant as the present invention.
JP 2004-225657 A

  However, since the casing 4 accommodating the oxidation catalyst 2 and the particulate filter 1 in the previous stage is composed of a relatively thin sheet metal part, as shown in an enlarged view in FIG. When the welding is performed from the outside, the back bead 7 swells inside the casing 4 due to the welding penetration, or welding distortion occurs, and the roundness at the welded portion of the casing 4 is reduced. There is a problem that it is difficult to press fit into the casing 4, and if the press fitting is performed forcibly, the preceding oxidation catalyst 2 and particulate filter 1 may be damaged.

  The present invention has been made in view of the above-described circumstances, so that welding can be performed at a necessary portion of the casing without hindering press-fitting of the exhaust purification catalyst such as an oxidation catalyst or a particulate filter into the casing. An object of the present invention is to provide an exhaust emission control device.

The present invention relates to an exhaust purification device in which an exhaust purification catalyst that purifies by passing exhaust gas is housed in a casing in the middle of an exhaust pipe, where a portion of the casing that holds the exhaust purification catalyst is required to be welded. , Without combining a plurality of sheet metal parts, forming a bulge that swells outward in the radial direction,
A hanging tool is welded to the bulging part from the outside, and the casing is supported on the vehicle body side through the suspending tool. The swelling of the bulging part is caused by welding distortion caused by welding of the hanging tool and the inside of the casing. Constructed to allow back bead ,
The exhaust purifying catalyst is press-fitted into the casing and accommodated after welding the hanger to the outside of the bulging portion .

  Thus, even if welding is performed from the outside of the bulge portion of the casing in this way, the back bead and weld distortion due to the weld penetration are allowed in the bulge portion. Therefore, it is possible to weld the necessary portion of the casing.

Further, in the present invention, welding the hanger from the outside to the bulge portion, and because Shi so supporting the casing on the vehicle body side via the the hanging Ri ingredients, Thus, the exhaust gas purifying catalyst of the casing It is possible to weld the hanger to the holding part without hindrance and to effectively suspend and support the position where the load of the exhaust purification catalyst is directly applied by the hanger from the vehicle body side.

  According to the exhaust emission control device of the present invention described above, various excellent effects as described below can be obtained.

(I) According to the onset bright, be subjected to welding from the outside of the bulged portion of the casing, it is possible to permit the back bead and welding distortion due to the welding penetration at the bulging portion, the oxidation catalyst and particulate matter Welding can be satisfactorily applied to the necessary part of the casing without hindering the press-fitting of the exhaust purification catalyst such as a filter into the casing, and smooth press-fitting of the exhaust purification catalyst into the casing can be realized. Thus, the exhaust purification catalyst can be prevented from being damaged.

(II) According to the onset bright, since the hanger to sites that are holding an exhaust gas purification catalyst of the casing can be welded without any problem, the position according load of the exhaust gas purification catalyst directly by the hanging Ri tool It can be effectively suspended and supported from the vehicle body side.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an example of an embodiment for carrying out the present invention. In the same manner as in the above-described drawings, a preceding oxidation catalyst 2 (exhaust gas) is disposed in a casing 4 interposed in the middle of an exhaust pipe 3. Exhaust purification catalyst for purifying exhaust gas) and particulate filter 1 (in this case, the particulate filter itself is regarded as an exhaust purification catalyst as an oxidation catalyst integrally supported by a carrier) In the portion where the oxidation catalyst 2 and the particulate filter 1 in the front stage of the casing 4 are held, the welding distortion and the back bead 7 can be allowed at the portion where the hanging tool 5 is to be welded. A bulging portion 8 that bulges outward in the radial direction is formed.

  Thus, with this configuration, even if the hanger 5 is welded to the outside of the bulging portion 8 of the casing 4, the back bead 7 and welding distortion due to the welding penetration are allowed in the bulging portion 8. Thus, there is no problem in press-fitting the preceding stage oxidation catalyst 2 and the particulate filter 1 into the casing 4, and welding can be performed at a necessary portion of the casing 4.

  Therefore, according to the above embodiment, even if welding is performed from the outside of the bulging portion 8 of the casing 4, the back bead 7 and welding distortion due to the weld penetration can be allowed by the bulging portion 8. Further, welding can be satisfactorily performed at a necessary portion of the casing 4 without hindering the press-fitting of the oxidation catalyst 2 in the previous stage such as the particulate filter 1 or the particulate filter 1 into the casing 4. A smooth press-fitting of the preceding oxidation catalyst 2 and the particulate filter 1 into the inside can be realized, and damage to the preceding oxidation catalyst 2 and the particulate filter 1 can be avoided in advance.

  In addition, since the hanger 5 can be welded to the portion of the casing 4 holding the oxidation catalyst 2 or the particulate filter 1 in the front stage without any trouble, the hanger 5 can be used to weld the front stage oxidation catalyst 2 or the particulate filter. The position where the load of the filter 1 is directly applied can be effectively suspended and supported from the vehicle body side.

Note that the exhaust purification device of the present invention is not limited to the above-described embodiment. The exhaust purification catalyst housed in the casing in the middle of the exhaust pipe is not necessarily provided with a particulate filter or an anterior stage thereof. It is not limited to that the oxidation catalyst, NOx storage reduction catalyst, selective catalytic reduction catalyst may be a variety of catalysts such as three-way catalysts and the like that, and other various modifications without departing from the gist of the present invention Of course, can be added.

It is sectional drawing which shows an example of the form which implements this invention. It is sectional drawing which shows a prior art example. It is sectional drawing to which the welding location of the hanger of FIG. 2 was expanded.

Explanation of symbols

1 Particulate filter (exhaust gas purification catalyst that purifies exhaust gas through)
2 Oxidation catalyst (exhaust gas purification catalyst that purifies by passing exhaust gas)
3 Exhaust pipe 4 Casing 5 Lifting tool 6 Car body 7 Back bead 8 Swelling part

Claims (1)

An exhaust gas purification apparatus in which an exhaust gas purification catalyst for purifying exhaust gas is contained in a casing in the middle of an exhaust pipe, wherein a plurality of metal plates are attached to a portion of the casing that holds the exhaust gas purification catalyst and requires welding. Without combining parts, form a bulge that bulges radially outward,
Welding a hanging tool from the outside to the bulging portion, and supporting the casing on the vehicle body side through the hanging tool,
The bulge of the bulging part is configured to allow welding distortion and back bead inside the casing accompanying welding of the lifting tool ,
An exhaust emission control device , wherein the exhaust purification catalyst is press-fitted and accommodated in the casing after the hanging tool is welded to the outside of the bulging portion .

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