JP2004162702A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact exhaust emission control device having a purification function and a sound eliminating function, and to set the thickness of a second case having the sound eliminating function to be thinner than a first case to secure heat resistance and high strength performance of the first case while achieving light weight. <P>SOLUTION: The first case 1 is formed cylindrical to comprise a main body part 3 of a large diameter, parts 4a and 4b of a small diameter, and tapered parts 5a and 5b connecting the neck parts 4a and 4b to the main body part. A columnar body 6 around which shock absorbing material 7 is wound is contained in the first case 1. An end part 9a of the second case 8 of a cylindrical form formed thinner than the first case 2 is engaged with the main body part of the first case 2 to form a sound eliminating chamber of the second case 8. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to an exhaust gas purification device.

  2. Description of the Related Art Conventionally, an exhaust system of a vehicle accommodates a column such as a catalyst carrier and a diesel particulate filter (DPF) in a large-diameter case in an exhaust pipe for guiding exhaust gas discharged from an engine to the rear of the vehicle. An exhaust purification device for purifying exhaust gas, a muffler for silencing exhaust noise having one or more muffle chambers formed in a large-diameter case, and the like are connected and arranged.

In such an exhaust system, as shown in FIG. 7, an exhaust purification device in which a catalytic converter and a muffler are housed in one case is known. In the exhaust gas purification apparatus, a partition 105 provided with a throttle passage 104 is attached at substantially the center of a case 103 having an inflow port 101 and an outflow port 102 to form a catalyst chamber 106 and a muffling chamber 107. A catalyst carrier 108 is held in a catalyst chamber 106 via a buffer material 109. With such a configuration, it is possible to provide an exhaust purification device which has a function of purifying and silencing, and is compact and has a small number of parts (see Patent Document 1).
Japanese Utility Model Laid-Open No. 2-110224 (pages 3 and 4, FIG. 1)

  By the way, the weight of the exhaust system components is desired for the purpose of improving the fuel efficiency of the vehicle, and the thickness of the silencer case tends to be reduced. However, an exhaust gas purification device needs to keep the internal column for many years against high temperature exhaust gas pressure and vibration, so strong case rigidity is indispensable, and the case is made thinner like a silencer ( Low rigidity).

  Therefore, as in the conventional case where the exhaust gas purification device and the muffler are formed in one case, the entire case thickness must be set with emphasis on the case rigidity of the exhaust gas purification device portion. However, it has been difficult to reduce the thickness of the case of the silencer, that is, to reduce the weight.

  Therefore, an object of the present invention is to provide an exhaust gas purifying apparatus which has both a purifying function and a silencing function, and which can achieve weight reduction, compactness, heat resistance, and high strength.

  In order to solve the above-mentioned problems, a first invention according to claim 1 is a cylindrical shape in which a large-diameter main body portion is integrally formed with a small-diameter neck portion, and a tapered portion connecting the main body portion and the neck portion. A column having a buffer material wound around the outer periphery is accommodated in the first case, and an end of a cylindrical second case formed thinner than the first case is fitted to a main portion of the first case. An exhaust gas purification apparatus characterized in that a sound deadening chamber is formed in the second case portion.

  According to a second aspect of the present invention, an outer peripheral portion is provided in a cylindrical first case in which a small-diameter neck portion and a tapered portion connecting the main portion and the neck portion are integrally formed at both ends of a large-diameter main portion. The first case is accommodated with a pillar body having a cushioning material wound around the second case, and the end of a cylindrical second case formed thinner than the first case is fitted to the main body of the first case. An exhaust gas purifying apparatus characterized in that a muffler chamber is formed in a section.

  According to a third aspect of the present invention, there is provided the exhaust gas purifying apparatus according to the first or second aspect, wherein at least a portion of the main body in the first case for accommodating the buffer material is reduced in diameter. is there.

  As described above, according to the present invention, it is possible to provide a compact exhaust gas purifying apparatus having both a purifying function and a silencing function by fitting the end of the second case to the main part of the first case. Can be.

  Furthermore, by forming the plate thickness of the second case thinner than that of the first case, it is possible to contribute to a reduction in vehicle weight without impairing the holding performance of the column.

  Furthermore, since the main body and the neck of the first case that hold the column are integrally formed, heat resistance and high strength of the first case can be secured.

  The best mode for carrying out the present invention will be described based on an embodiment shown in FIGS.

FIG. 1 shows a first embodiment.
The first embodiment shows an example in which the exhaust gas purification apparatus 1 according to the present invention is connected to an exhaust manifold 12 attached to an engine.

A first case 2 made of a metal (for example, stainless steel and having a plate thickness of 1.2 mm) has small-diameter necks 4a and 4b at both ends of a large-diameter main body 3, and the main body 3 and the neck. The tapered portions 5a and 5b connecting the tapered portions 4a and 4b are necked by spinning to be integrally formed.
The plate thickness of the first case 2 is set in consideration of the case rigidity required to hold the carrier (column) 6 and the strength when the second case 8 described below is fitted.

  Inside the main body 3 of the first case 2, a honeycomb-shaped ceramic carrier 6 (pillar) in which a cushioning material 7 formed by molding ceramic fibers into a mat shape is wound around the outer periphery. A large number of passages in the carrier 6 carry a catalyst. The cushioning material 7 is compressed by being sandwiched between the main body 3 and the carrier 6, and the carrier 6 is firmly held by the main body 3 by the restoring force (repulsive force).

  The second case 8 is formed of a cylindrical body made of metal (for example, made of stainless steel and having a thickness of 0.8 mm) thinner than the first case 2, and the main body 9 is formed of a main body of the first case 2. 3 has an outer diameter substantially the same as that of the outer diameter 3.

  The upstream side of the main part 9 of the second case 8 is opened, and after its upstream end 9a is fitted to the small-diameter stepped part 3a provided in the main part 3 of the first case 2, any welding such as laser welding is performed. The silencing chamber 10 is formed by the second case 8 in an airtight manner by the method.

  The downstream end 9b of the second case 8 is formed in a neck portion having a reduced diameter. The downstream end 9b is formed from the main body 9a through a tapered portion 9c, and the tapered portion 9c and the downstream end 9b are reduced in diameter by spinning so as to have an axis inclined with respect to the axis of the second case. The downstream end 9b is provided with a flange 11 for connecting a downstream exhaust pipe (not shown). Such a processing method of performing the spinning processing by inclining the axis can be performed by the method described in Japanese Patent No. 2957154.

  The exhaust gas purification device 1 configured as described above has its upstream neck 4a fitted to the downstream pipe 12a of the exhaust manifold 12 that collects and exhausts exhaust gas discharged from each port of the engine. They are connected by welding or the like.

  In the configuration described above, the exhaust gas introduced from the exhaust manifold 12 into the exhaust gas purification device 1 is purified of harmful components in the exhaust gas by the carrier 6 provided in the first case 2. Thereafter, the exhaust gas and the exhaust noise are guided through the neck 4b into the silencing chamber 10 formed by the second case 8. At this time, the exhaust noise is silenced by the energy attenuating effect due to the expansion when flowing out of the small-diameter neck 4b into the large-diameter, large-capacity silencing chamber 10. Thereafter, the exhaust gas is guided from the downstream end 9b of the second case 2 to a downstream exhaust pipe (not shown).

  According to the first embodiment, by fitting the second case 8 to the main body 3 of the first case 2, it is possible to provide a compact and integrated exhaust purification device having both a purifying function and a silencing function. it can.

  Further, since the thickness of the second case 8 is made thinner than the thickness of the first case 2, it is possible to contribute to a reduction in vehicle weight without impairing the holding performance of the carrier 6 by the first case 2. it can. Although not adopted in the above embodiment, the first case 2 and the second case 8 can be made of different materials depending on heat resistance, durability, workability, and the like. Can contribute.

  Further, in the present embodiment, the tapered portion 5b on the outlet side to which the high temperature exhaust gas passes through the carrier 6 is formed integrally with the first case 2, so that the durability of the tapered portion 5b is improved. In addition, the durability of the exhaust gas purification device can be improved.

FIG. 2 shows a second embodiment.
The second embodiment shows an example in which the present invention is applied to an exhaust emission control device arranged under the floor of a vehicle.

  In a first case 22 made of a metal tubular body constituting the exhaust gas purifying apparatus 21 of the second embodiment, small-diameter necks 24a and 24b are provided at both ends of a large-diameter main body 23, Tapered portions 25a, 25b connecting necks 24a, 24b are integrally formed by spinning.

Incidentally, the neck portion 24b of the downstream side is formed in the offset OF ₁ was eccentric shape with respect to the main body portion 23. For such eccentric processing, for example, an eccentric spinning method described in Japanese Patent No. 2957153 can be used. Inside the main body portion 23 of the first case 22, a honeycomb-shaped ceramic carrier 26 (pillar) in which a cushioning material 27 formed by molding ceramic fibers into a mat shape is wound around the outer periphery is accommodated.

  The central part 23a of the main body part 23 is slightly reduced in diameter after the buffer material 27 and the carrier 26 are loosely inserted and compresses the buffer material 27, thereby holding the carrier 6 firmly. This method is a so-called sizing method, which is well known in the production of catalytic converters (for example, Japanese Patent No. 2679857).

The second case 28 is formed of a metal tubular body thinner than the first case 22, and the main portion 28 a has an outer diameter larger than the main portion 23 of the first case 22. Have been. Furthermore, the upstream end 29a of the second case 28 is reduced in diameter by the eccentric state of the axis and offset OF ₂ of the second case 28, after fitted to main body portion 23 of the first case 22, such as by laser welding Airtightly joined. Further, the downstream end 29b of the second case 28 is reduced in diameter in an eccentric state offset from the axis of the second case 28 on the opposite side to the upstream end 29a.

  The inside of the second case 28 is divided into two muffling chambers 30a and 30b by a partition plate 31 having a large number of small holes 31a. Further, an inlet pipe 32 is provided in the second case 28 with its upstream side fitted into the neck 24b of the first case 22 and its downstream side inserted through the partition plate 31. Further, an outlet pipe 33 is provided in the second case 28 so that its downstream side is fitted to the downstream end 29b of the second case 28 and its upstream side is inserted through the partition plate 31. The outlet pipe 33 has a large number of small holes 33a.

The exhaust gas purification device 21 configured as described above is disposed under the floor of the vehicle, and an exhaust pipe (not shown) is connected to the neck 24a and the downstream end 29b.
Same effect as the first embodiment also in the second embodiment, on which can exhibit the effect, since the first case 22 and second case 28 is eccentric OF _2, the arrangement of the floor of the vehicle Easier to do.

FIG. 3 shows a third embodiment.
The third embodiment is a modification in which the structure of the downstream side wall of the second case 28 in the second embodiment is different.

  That is, the second case 48 of the exhaust gas purification device 41 is fitted with a cylindrical shell 50 whose downstream side is opened with substantially the same diameter as the main portion 48a so as to close the downstream end 49b of the shell 50 and laser welding. The end plate 51 is hermetically joined by the above method. The upstream end 49a of the shell 50 is formed similarly to the upstream end 29a of the second case 28 of the second embodiment.

Since other configurations are the same as those of the second embodiment, the same portions as those described above are denoted by the same reference numerals as those described above, and description thereof is omitted.
In the third embodiment having the above configuration, the same operation and effect as those of the second embodiment can be exhibited.

FIG. 4 shows a fourth embodiment.
In the fourth embodiment, the second case 68 of the exhaust gas purification device 61 is fitted with a cylindrical shell 70 whose both ends are opened with substantially the same diameter as the main body portion 68a, and both ends of the shell 70 are closed. It is composed of end plates 71 and 72 which are hermetically joined by laser welding or the like. The shell 70 is formed by winding a thin steel plate (for example, a plate made of stainless steel and having a thickness of 0.4 mm) 70a twice as shown in FIG. Although the steel plate 70a may be wound twice or more, it is desirable that the total plate thickness t be thinner than the plate thickness of the first case 22. The open end 72a of the upstream end plate 72 is airtightly joined by laser welding or the like after fitting to the main body 23 of the first case 22.

Since other configurations are the same as those of the second embodiment, the same portions as those described above are denoted by the same reference numerals as those described above, and description thereof is omitted.
In the fourth embodiment, the same operation and effect as those of the second embodiment can be exhibited.
Further, since the main body 68a of the second case 68 is made of a double plate, sound radiated from the second case 68 can be suppressed.

5 and 6 show a fifth embodiment.
The first case 82 of the exhaust gas purification device 81 in the fifth embodiment includes a small-diameter neck portion 84a formed at one end on the upstream side of the large-diameter main portion 83, and the main portion 83 and the neck portion 84a. The connecting tapered portion 85a is formed integrally by spinning. On the other hand, the neck portion and the tapered portion are not provided on the downstream side 83b of the main portion 83, and the large-diameter main portion 83 is open.

  The second case 88 has a cylindrical shell 90 whose both ends are opened with substantially the same diameter as the main body portion 88a, an end plate 91 fitted to close both ends of the shell 90 and hermetically joined by laser welding or the like. 92. The shell 90 has an elliptical cross section as shown in FIG. Therefore, the cross section of the end plate 92 at the tapered portion 92b is changed into an ellipse from the circular neck portion 92a toward the second case 88. In the second case 88, a partition plate 94 is formed so as to be divided into two muffling chambers 95a and 95b. Further, an outlet pipe 96 having a large number of small holes 96a is provided. The open end plate 92a of the end plate 92 on the upstream side is air-tightly joined by laser welding or the like after fitting to the main portion 83 of the first case 82. The same parts as those in the second embodiment are denoted by the same reference numerals as those described above, and description thereof is omitted.

In the fifth embodiment, the same operation and effect as in the second embodiment can be exhibited.
Note that the axis of the first case 82 and the axis of the second case 88 may be set relatively non-coaxial, and this relative angle difference may be absorbed by deformation of the end plate 92.

  As described above, in the first to fifth embodiments, the second case 8, 28, 48, 68, 88 is replaced with the column 6, the main body 3, 23, 83 of the first case 2, 22, 82. By fitting to the end downstream of 26, overheating of the columns 6, 26 can be prevented, and deterioration of the columns 6, 26 can be prevented.

  When the main parts 3, 23, 83 of the first cases 2, 22, 82, and the second cases 8, 28, 48, 68, 88 are joined by welding or the like, they are positioned so as not to overlap the cushioning materials 7, 27. It is preferable to join by welding or the like.

  Also, in the first and second embodiments, each of the second cases 8, 28 may be composed of a plurality of members as in the third to fifth embodiments. In the case where the second cases 8 and 28 are formed of a plurality of members as described above, the thickness of the main portions 9 and 28a may be configured to be thinner than the thickness of the first cases 2 and 22.

  Further, the carriers 6 and 26 shown in each of the above-described embodiments are formed by supporting a noble metal on a honeycomb-shaped ceramic. Instead of this carrier, a part of the passage of the honeycomb-shaped ceramic is sealed, and the exhaust gas is exhausted. DPF (Diesel Particulate Filter) for removing fine particles therein may be used. In addition to the honeycomb-shaped ceramic, a porous ceramic formed in a columnar shape may be used as the carrier or the DPF. Therefore, in the present invention, these carriers, DPFs and the like are collectively referred to as pillars.

  In addition to the non-thermally-expandable cushioning material (alumina mat) formed by accumulating the ceramic fibers shown in the above embodiment and forming a mat, the cushioning materials 2 and 27 are made of a thermally-expandable buffer to which vermiculite is added. The material may be used, and the presence or absence and content of the binder are not limited.

  Further, the plate-like cushioning material (mat) may be wound in a columnar shape, or a pillar may be inserted into the cylindrical cushioning material. Further, a cushioning material obtained by corrugating heat-resistant metal fibers may be used, or may be used in combination with the above-mentioned ceramic fiber cushioning material.

  As the structure of the sound deadening chamber, a well-known sound deadening room structure such as a resonance type, a sound absorbing type (installing a sound absorbing material), an interference type, etc. can be adopted in addition to the expanded type structure shown in the above embodiment. A well-known variable valve or the like may be combined.

  Further, two or more pillars and cushioning members may be arranged in series (tandem) in the axial direction. Also, the cross-sectional shape is not limited to a circle, but is arbitrary. In the above embodiment, the necking portion is integrally formed by spinning. However, in the present invention, the necking portion may be integrally formed by another method, or a separate necking may be provided if the function and durability can be satisfied. The unit may be connected to the main unit. Further, in the present invention, the first embodiment described above may be combined with the second to fifth embodiments.

  Further, the present invention is not only applied to the exhaust system of the internal combustion engine of the vehicle, but requires the purification (reforming) and silencing functions of the vehicle, such as the exhaust system of the fuel cell system or the exhaust system of the heaters. Widely applicable to such devices.

FIG. 1 is a sectional view showing a first embodiment of the present invention. Sectional drawing which shows the 2nd Example of this invention. Sectional drawing which shows the 3rd Example of this invention. FIG. 6 shows a fourth embodiment of the present invention, in which (a) is a cross-sectional view of an exhaust gas purification device, and (b) is an enlarged cross-sectional view of a portion A in (a). Sectional drawing which shows the 5th Example of this invention. FIG. 6 is a sectional view taken along line BB in FIG. 5. Sectional drawing which shows the conventional structure.

Explanation of reference numerals

2, 22, 28 First case 3, 23, 83 Main part 4a, 4b, 24a, 24b, 84a Neck 5a, 5b, 25a, 25b, 85a Tapered part 6,26 Column 7,27 Buffer material 8,28, 48, 68, 88 Second case 9a, 29a, 49a, 72a, 92a End 10, 30a, 30b, 95a, 95b Sound deadening chamber

Claims (3)

  In a cylindrical first case integrally formed with a small-diameter neck portion in a large-diameter main body portion and a tapered portion connecting the main body portion and the neck portion, a column body having a buffer material wound around an outer periphery is housed, The exhaust part is characterized in that an end of a cylindrical second case formed thinner than the first case is fitted to a main part of the first case, and a muffling chamber is formed by the second case. Purification device.   A cylindrical body in which a cushioning material is wound around the outer periphery is accommodated in a cylindrical first case in which a small-diameter neck portion at each end of a large-diameter main body portion and a tapered portion connecting the main body portion and the neck portion are integrally formed. The end of a cylindrical second case formed thinner than the first case is fitted to the main body of the first case to form a sound deadening chamber in the second case. Exhaust purification device.   The exhaust gas purifying apparatus according to claim 1, wherein at least a portion of the main body of the first case that accommodates the cushioning material is reduced in diameter.

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