JP2002038919A - Exhaust emission purifier for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission purifier, which can perform the silencing of and emission control of exhaust gas from an engine of a diesel car at high efficiency and is small, high in performance and long in life. SOLUTION: In this exhaust emission purifier an annular high temperature catalytic chamber 22 and first/second annular trap chambers 24, 26 are arranged between expansion chambers 18, 20 in a muffler housing 16, a heat transfer pipe 36 is arranged in the central part of these annular chambers, inside the annular catalytic chamber 22 is charged with a heat accumulator unit 46 consisting of NOx catalyst, inside the annular trap chambers 24, 26 is charged with filter members 52, 54, a resonance chamber 38 is formed in the heat transfer pipe 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying device for an engine, and more particularly to an exhaust gas purifying muffler effective as a device (DPF) for removing suspended particulates (SPM) of a diesel engine.

[0002]

2. Description of the Related Art In U.S. Pat. Nos. 4,324,572, 4,576,799 and 5,171,341, a plurality of perforated tubes having a filter element in a casing are arranged. A structure has been proposed in which one end is blocked and SPM in the exhaust gas is trapped by allowing the exhaust gas to enter the space of the tube from multiple ends and pass through a filter element. In these structures, the filter element is composed of an inorganic fiber having a large number of micropores, but the filter element is clogged by SPM and has a short filter life. Moreover, inorganic fibers are vulnerable to vibration,
There was a disadvantage that the filter was easily damaged.

[0003] US Patent Nos. 4,419,113, 4,
Nos. 813,231 and 5,892,186 propose a diesel particulate trap muffler in which a plurality of filter elements are arranged in the longitudinal direction of a casing. In these structures, SPM in exhaust gas
As in the prior art described above, the fuel accumulated in the filter significantly reduces the life of the filter, and the engine back pressure increases to deteriorate the fuel efficiency of the diesel vehicle.

In US Pat. Nos. 5,663,537 and 5,992,560, a casing having an expansion chamber is disposed around an exhaust pipe having a large number of small holes, and a filter element is disposed in the expansion chamber. Exhaust gas purification mufflers have been proposed. In these technologies, the structure is such that the entire amount of exhaust gas does not contact the filter element,
The trapping efficiency and silencing effect of SPM were low.

US Pat. Nos. 5,908,480 and 6,013,118 propose an exhaust gas purifying apparatus employing a filter element having a honeycomb structure or a multi-cylindrical structure having an exhaust gas introduction space and an exhaust space. I have. These techniques have the same disadvantages as the prior art mentioned above. For this reason, an electric heater is built in the filter, and the heater is operated intermittently to burn the SPM deposited in the filter. However, in order to stop the filter function during the operation of the heater, two filter elements are combined and operated alternately. For this reason, the exhaust gas purifying apparatus is structurally large, complicated, and costly. further,
Since a large current of 150 to 200 amperes flows through the heater, it is necessary to replace the alternator of the diesel vehicle with a large capacity one, which significantly increases the total cost.

[0006]

As described above, the conventional exhaust gas purifying apparatus has a low SPM trap performance, a short trap life, and is large and expensive. Further, a diesel vehicle needs to be replaced with a large-capacity alternator instead of the conventional one, resulting in a remarkably high total cost.

An object of the present invention is to provide a small, high-performance, compact, high SPM trapping efficiency,
An object of the present invention is to provide an exhaust gas purifying muffler for a diesel engine, which has a long trapping performance, a long life, a high silencing efficiency, and an extremely low cost.

[0008]

SUMMARY OF THE INVENTION In an exhaust gas purifying muffler for a diesel engine according to the present invention, an expansion chamber is formed adjacent to an inlet of a muffler housing, and an annular high-temperature catalyst chamber and an annular trap are sequentially arranged downstream of the expansion chamber. The annular catalyst chamber and the annular trap chamber are thermally connected by a heat transfer pipe, and the annular catalyst chamber is filled with a regenerator made of a NOx removing catalyst. A heat conductive filter member composed of a demister roll is filled.

[0009]

According to the present invention, a large amount of shunts are generated from exhaust gas in the annular high-temperature catalyst chamber, and these are muted while repeating collision interference with each other, and at the same time, NOx is removed. SPM partially burns due to residual oxygen. Next, the high-temperature exhaust gas is trapped in the SPM while passing through a filter member composed of a metal wire mesh demister and a roll in the annular trap chamber. These SPMs are burned and purified by the high-temperature energy transmitted by the heat transfer pipe, and the noise is reduced. Is attenuated by colliding with the filament of the filter member.

FIG. 1 shows an exhaust gas purifying muffler for a diesel engine according to a preferred embodiment of the present invention, with reference to the drawings. 1 and 2, the muffler 10 includes a muffler housing 16 having an exhaust gas introduction inlet 12 and a purified gas discharge outlet 14. The muffler housing 16 includes first and second expansion chambers 18 and 20 formed adjacent to the inlet 12 and the outlet 14, respectively.
And a first and second annular trap chambers 24 and 26 formed on the downstream side. First expansion room 1
8. In the annular high-temperature catalyst chamber 22 and the first and second annular trap chambers 24 and 26, heat-resistant heat insulating layers 28, 30, 32 and 34 made of glass fiber mats or the like are arranged. Insulation material 2
8 is held at a fixed position by a pressing member 29 such as punching metal. At the center of the annular catalyst chamber 22 and the first and second annular trap chambers 24 and 26, a heat transfer pipe 36 of high thermal conductivity such as a copper pipe extends, and a resonance chamber 38 is formed therein. Heat transfer pipe 36 is annular catalyst chamber 2
2 and a plurality of small holes 36a communicating with the first and second annular trap chambers 24 and 26. A small hole 36 b is formed at an end of the heat transfer pipe 36.

The annular catalyst chamber 22 has a front plate 40 having a front opening 40a communicating with the first expansion chamber 18.
And a rear plate 42 having a rear opening 42a formed at a position opposite to the front opening 40a, that is, at a position 180 degrees out of phase.
Further, as shown in FIG. 2, the annular catalyst chamber 22 includes a first exhaust gas flow branch zone 2 adjacent to the front opening 40a.
2a, first arc zones 22b and 22b 'for passing the exhaust gas flow in opposite directions, and an exhaust gas interference zone 22c adjacent to the rear opening 42a for causing collision and interference with the branched exhaust gas flow to mute the sound. Front opening 40
A small mesh metal mesh 44 is fixed inside a, and the ring catalyst chamber 22 is filled with a heat storage body 46 made of a NOx removal catalyst containing γ-alumina having a particle size of 2 to 4 mm.

Partition plates 48 and 50 are disposed in the first and second annular trap chambers 24 and 26, respectively. The partition plate 48 has an opening 48a formed at a position opposite to the rear opening 42a. The partition plate 50 is formed at a position opposite to the opening 48a, and
It has an opening 50a that communicates with zero. The first and second annular trap chambers 24 and 26 are filled with heat conductive filter members 52 and 54, respectively, which are made of a wave-shaped metal wire mesh demister roll. The filter members 52 and 54 are formed of spirally formed rolls of a wave-like stainless steel mesh having meshes of wire diameters of 0.05 to 0.5 mm and 0.5 to 10 mm, respectively. The resistance is low, and the engine back pressure is prevented from rising. Moreover, since the contact surface area of the wire mesh demister is enormous, the trapping efficiency of the SPM is extremely high. Inside the first trap chamber 24, an exhaust gas flow branching zone 24a adjacent to the opening 42a, an arc zone (not shown), and an exhaust gas interference zone 24 communicating with the opening 48a.
c. Similarly, the interior of the second trap chamber 26 has an exhaust gas flow branch zone 26a adjacent to the opening 48a, an arc zone (not shown), and an exhaust gas interference zone 26c adjacent to the opening 50a.

In the above configuration, the dynamic pressure of the exhaust gas flowing from the inlet 12 into the first expansion chamber 18 changes to a static pressure, and the pressure of the exhaust gas increases. The high-pressure exhaust gas flows into the annular high-temperature catalyst chamber 22 through the front opening 40a. Next, the exhaust gas passes through these gaps while being in contact with the surface of the granular γ-alumina, is branched in two directions in the exhaust gas flow branching zone 22a, gas oils in the arc zones 22b, 22b ′, and the exhaust gas flow interference zone 22c The noise is efficiently reduced by colliding and interfering with each other. While the exhaust gas passes through the gap between the granular heat storage bodies 46, a large number of shunts are generated from the exhaust gas flow, which repeatedly collide with each other and interfere with each other to further effectively reduce noise. At this time, the temperature of the exhaust gas in the annular high-temperature catalyst chamber 22 becomes a high temperature of 550 ° C. to 900 ° C., and the temperature is changed via the heat transfer pipe 36 to the wire mesh demister rolls 52 of the first and second trap chambers 24 and 26. 5
4 and the wrap chambers 24, 26 are also maintained at a high temperature. While the exhaust gas moves in the circumferential catalyst chamber 22 in the circumferential direction, the exhaust gas contacts the surface of γ-alumina to remove NOx, and the SPM partially burns at a high temperature. in this way,
The primary exhaust gas and the primary silenced exhaust gas are supplied to the rear opening 42a.
Then, while being moved in the circumferential direction within the filter member 52 in the first trap chamber 24, the secondary purification and the secondary noise are performed. Next, the exhaust gas is further purified and reduced in noise while moving in the circumferential direction in the filter member 54 in the second trap chamber 26. As described above, according to the present invention, the trapped SPM is automatically burned continuously while the vehicle is running inside the filter without relying on the electric heater, so that the filter can be prevented from being clogged and the exhaust gas purification muffler has a long service life. This has the effect of making the realization possible. Further, since the filter members in the first and second trap chambers are made of a wire mesh demister having a high aperture ratio, the flow resistance of the exhaust gas is small. For this reason, an increase in engine back pressure is prevented, and deterioration of fuel efficiency is prevented.

[0014]

As is clear from the above, according to the present invention, a small-sized, high-performance, long-life, low-cost exhaust gas purification muffler can be provided, and a great contribution to environmental measures can be expected.

[Brief description of the drawings]

FIG. 1 is a sectional view of an exhaust gas purifying muffler for a diesel engine according to a preferred embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

[Explanation of symbols]

12 inlet, 14 outlet, 16 housing, 18, 20 expansion chamber, 22 annular high temperature catalyst chamber, 2
4, 26 annular trap chamber, 28, 30, 32, 34
Heat insulation material layer, 36 heat transfer pipe, 38 resonance chamber, 46 heat storage body, 52, 54 filter member

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F01N 1/02 F01N 1/02 N 1/04 K 1/04 1/06 G 1/06 3/24 J 3/24 LQ ZABE ZAB 3/28 N 3/28 7/14 7/14 B01D 53/36 103B 103C F term (reference) 3G004 BA01 BA03 BA06 CA01 CA04 CA12 CA14 DA06 DA08 DA09 DA21 EA05 FA04 GA01 3G090 AA04 BA01 EA01 EA02 3G09 A AB05 BA00 BA04 BA14 BA38 CA10 GA04 GA21 GB01W GB01X GB06W GB10W HA05 HA15 HA47 4D048 AA06 AA14 AB01 AB03 BA03X BA41X BB01 BB05 BB12 CA07 CC23 CC25 CC26 CC38 CD05 CD08 4D058 JA60 JB03 JB32 QA17 SA06 TA06 UA

Claims (4)

[Claims] A muffler housing having an inlet and an outlet; an expansion chamber formed in the muffler housing adjacent to the inlet; an annular high-temperature catalyst chamber disposed downstream of the expansion chamber; An annular trap chamber disposed on the downstream side of the pipe; a heat transfer pipe for thermally connecting the annular high-temperature catalyst chamber and the annular trap chamber to each other; a high-temperature catalyst chamber and an annular trap chamber formed in the heat transfer pipe A regenerator made of a NOx removal catalyst filled in a high-temperature catalyst chamber; and a heat transfer material made of a wave-shaped metal wire mesh demister and roll filled in an annular trap chamber and heated by a heat transfer pipe. An exhaust gas purification muffler for a diesel engine, comprising: a filter member; 2. The first exhaust gas flow branch zone in which the annular high-temperature catalyst chamber communicates with the expansion chamber, the first circular arc zone through which exhaust gas flows in opposite directions, and the branch exhaust gas flow collide with each other. A first exhaust gas flow interference zone, wherein the annular trap chamber is adjacent to the first exhaust gas flow interference zone, a second exhaust gas flow branching zone, a second arc zone for passing the exhaust gas flow in opposite directions, and a branch exhaust gas flow. An exhaust gas purifying muffler for a diesel engine, comprising a second exhaust gas flow interference zone causing collision interference. 3. The exhaust gas purifying muffler for a diesel engine according to claim 1, further comprising a heat insulating material layer disposed on inner walls of the expansion chamber, the annular high-temperature catalyst chamber, and the annular trap chamber. 4. The metal wire mesh demister roll according to claim 1, wherein the wire diameter is 0.05 to 1.5 m.
An exhaust gas purifying muffler for a diesel engine comprising a stainless steel mesh having a mesh of 0.5 m and 0.5 to 10 mm.