JP2008298036A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine or the like capable of efficiently removing NOx and the like in exhaust gas and improving the adsorption performance and desorption performance of a nitrogen oxide adsorbent. <P>SOLUTION: The exhaust emission control device comprises the nitrogen oxide adsorbent 10 temporarily adsorbing a nitrogen oxide such as NOx and desorbing the adsorbed NOx in an elevated temperature or a reduction atmosphere, an adsorbed material desorption means 11 disposed at the exhaust upstream side of the nitrogen oxide adsorbent 10 and bringing the exhaust gas in the elevated temperature or the reduction atmosphere, and a burning device 12 disposed at the exhaust downstream side of the nitrogen oxide adsorbent 10 and having a fuel supply section, an air supply section and an ignition section. The exhaust passage comprises an upstream exhaust passage 5 in which at least the adsorbed material desorption means 11 and the nitrogen oxide adsorbent 10 are disposed and a downstream exhaust passage 6 guiding the exhaust gas passing through the burning device 12 to the outer peripheral wall surface of a part where the nitrogen oxide adsorbent 10 of the upstream exhaust passage 5 is situated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus for purifying exhaust gas of an internal combustion engine such as a diesel engine, a gas engine, a gasoline engine or a gas turbine engine, or combustion equipment such as an incinerator or boiler, and in particular, is mainly installed in an exhaust passage and mainly composed of nitrogen oxides. And an exhaust gas purifying device for removing unburned components such as carbon monoxide.

Substances that are subject to exhaust gas purification are particulate substances such as nitrogen oxides, carbon monoxide, unburned hydrocarbons, and soot. Various devices for purifying these substances have been developed in the past.

  As a device for reducing nitrogen oxide (NOx), a denitration device that selectively reduces nitrogen oxide by installing a reduction catalyst using ammonia or urea as a reducing agent in the exhaust passage has been put into practical use. Yes. In addition, relatively small gas engines and gasoline engines for automobiles have developed three-way catalysts capable of simultaneously decomposing nitrogen oxides, carbon monoxide (CO), and unburned hydrocarbons (HC). Contributes to effective gas purification.

  However, the three-way catalyst exhibits a purification action effectively when operated within the stoichiometric air-fuel ratio or a range close thereto, but is effective under other conditions, particularly in exhaust gas with excessive air (oxygen). It has been found that it does not work. In order to cope with this, in a gas or gasoline engine operated in an excessive air state, nitrogen oxide is temporarily stored in the storage material during the operation in the above-described excessive air (oxygen) condition, and then the excess fuel is stored. A nitrogen oxide storage catalyst system that releases and reduces the stored nitrogen oxide by operating under conditions has been put into practical use.

  However, it has been found that the nitrogen oxide storage catalyst system poisons the catalyst by sulfur oxide (SOx) in the exhaust gas derived from the sulfur component in the fuel and the purification ability of nitrogen oxide decreases rapidly. Therefore, it is currently used only in engines that use low sulfur content fuel. In addition, nitrogen oxide is occluded by the occlusion material in the nitrogen oxide purification tower and burned in the same nitrogen oxide purification tower, thereby reducing the nitrogen oxide adsorbed on the occlusion material and sulfur oxide etc. Although the purification apparatus (patent document 1) of the structure which discharges | emits is also developed, since it is the structure which burns in the purification tower which contains an occlusion material, durability of an occlusion material becomes a problem in reality.

  Moreover, an electrostatic precipitator and a DPF have been put into practical use for removing particulate substances such as soot. The DPF physically captures particulate matter with a filter and incinerates and removes the captured particulate matter with an electric heater or the like, but recently, a catalytic component having an oxidizing action is removed by a particulate filter. A DPF that can be supported on a substrate and continuously remove particulate matter has also been developed.

  As described above, the three-way catalyst cannot exert its catalytic function in an internal combustion engine or a combustion device operated under an excess air condition, and is practical in a small gas engine or an automobile gasoline engine. In the above-described nitrogen oxide storage catalyst system, it is difficult to exert its purification ability effectively in exhaust gas containing sulfur oxide and particulate matter.

  Industrial internal combustion engines, combustion equipment, and marine internal combustion engines are mostly operated under excessive air conditions, and since fuel containing sulfur components is used, sulfur is contained in the exhaust gas. There is a demand for an exhaust gas purifying apparatus that contains a large amount of oxides and particulate matter and that can sufficiently exhibit performance even in such exhaust gas.

  A denitration device that selectively reduces nitrogen oxides using ammonia, urea, etc. is applied to relatively large industrial internal combustion engines and combustion equipment, but the device itself is large and very expensive. In addition, the maintenance cost of the reducing agents ammonia and urea is high. Furthermore, there is a high possibility that ammonia that is not consumed is released into the atmosphere.

In view of the problems of the conventional examples, the present applicant can remove particulate oxides such as nitrogen oxides and soot, carbon monoxide and unburned hydrocarbons in the exhaust gas, and without reducing the purification capacity thereof. An exhaust gas purification device that can be maintained has been developed and applied (Patent Document 2). In the exhaust gas purification device disclosed in Patent Document 2, the exhaust gas discharged from the exhaust passage during the adsorption operation and the combustion gas discharged from the exhaust passage during the desorption operation are discharged to the atmosphere, the internal combustion engine, etc. Or supply to the intake passage.
JP 2003-27927 A JP 2006-112313 A

  In the exhaust gas purifying apparatus of Patent Document 2 or the like, the adsorption performance and desorption performance of the nitrogen oxide adsorbent change depending on the temperature. That is, the allowable adsorption amount becomes maximum at a predetermined optimum temperature, and the allowable adsorption amount decreases even if the temperature falls below the optimum temperature or rises. Moreover, the nitrogen oxide desorption performance of the nitrogen oxide adsorbent improves as the temperature increases, and decreases as the temperature decreases.

  Specifically, during low load operation of the internal combustion engine, the temperature of the exhaust gas decreases and becomes lower than the optimum temperature of the nitrogen oxide adsorbent, so that the allowable adsorption amount of the nitrogen oxide adsorbent decreases and the adsorption Performance decreases.

  The present invention is an improvement of the exhaust gas purifying device disclosed in Patent Document 2 and the like. During the adsorption operation and the desorption operation, the exhaust gas or the combustion gas is converted into a nitrogen oxide adsorbent heat retaining medium or ascending temperature. The object is to improve the adsorption performance and desorption performance of the nitrogen oxide adsorbent by making it effectively usable as a warm medium.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a nitrogen oxide adsorbent that temporarily adsorbs nitrogen oxide and desorbs the adsorbed nitrogen oxide in a temperature rising or reducing atmosphere, and the nitrogen An adsorbent detachment means that is disposed upstream of the oxide adsorbent and makes the exhaust gas a temperature rising or reducing atmosphere, and a fuel supply unit and an air supply unit that are disposed on the exhaust downstream side of the nitrogen oxide adsorbent. And an exhaust gas purifying apparatus comprising an ignition part, wherein the exhaust passage includes at least an upstream exhaust passage in which the adsorbed substance desorbing means and the nitrogen oxide adsorbent are disposed, and the combustion A downstream exhaust passage that guides the exhaust gas that has passed through the apparatus to an outer peripheral wall surface of the upstream exhaust passage where the nitrogen oxide adsorbent is located.

  In the above configuration, the adsorbed substance desorbing means and the combustion device are stopped during normal operation of the internal combustion engine or the like, and nitrogen oxides in the exhaust gas discharged from the internal combustion engine or the like to the upstream exhaust passage are nitrogen oxides. Adsorbed on the adsorbent. The exhaust gas after adsorption of nitrogen oxides enters the downstream exhaust passage through the stopped combustion device, reaches the outer peripheral wall surface of the upstream exhaust passage where the nitrogen oxide adsorbent is located, Keep the oxide adsorbent warm. Thereby, the fall of NOx adsorption amount can be suppressed. In addition, unburned components such as hydrocarbons and carbon monoxide in the exhaust gas are oxidized and rendered harmless by a catalyst having an oxidizing action contained in the nitrogen oxide adsorbent.

  When the adsorption amount of the nitrogen oxide adsorbent reaches a predetermined amount (for example, a saturation amount), the adsorbed substance desorbing means and the combustion device are operated, and the exhaust gas or the combustion gas that has been heated to the reducing atmosphere by the adsorbed substance desorbing means Flows into the nitrogen oxide adsorbent, and nitrogen oxide is desorbed from the nitrogen oxide adsorbent. The desorbed nitrogen oxide is reduced and removed, for example, by the catalyst component of the nitrogen oxide adsorbent in the reducing atmosphere generated by the adsorbent desorbing means, or the fuel rich combustion region in the combustion flame of the combustion device Is reduced and removed. Then, the combustion gas heated by the combustion device and heated is passed through the downstream exhaust passage and reaches the outer peripheral wall surface of the upstream exhaust passage where the nitrogen oxide adsorbent is located. Exchange and raise the temperature of the nitrogen oxide adsorbent. Thereby, the desorption efficiency of nitrogen oxides is improved, and the reduction rate of nitrogen oxides and the energy consumption rate during nitrogen oxide regeneration are improved.

  According to a second aspect of the present invention, in the exhaust gas purifying apparatus according to the first aspect, the upstream exhaust passage is formed in an inner exhaust pipe connected to an internal combustion engine or combustion equipment, and the downstream exhaust passage is It is formed between the outer peripheral wall surface of the inner exhaust pipe and the inner peripheral wall surface of the outer exhaust pipe surrounding the inner exhaust pipe from the outside through an annular space.

  According to the above configuration, the entire nitrogen oxide adsorbing material can be kept warm from the outer peripheral side, or the temperature can be raised, and the adsorption performance and desorption performance of the nitrogen oxide adsorbing material can be further improved. . Further, it is possible to prevent the exhaust gas purification device from becoming large.

  According to a third aspect of the present invention, in the exhaust gas purifying apparatus according to the second aspect, heat exchange fins exposed in the downstream exhaust passage are formed on an outer peripheral wall surface of the inner exhaust pipe where the nitrogen oxide adsorbent is located. Is provided.

  According to the said structure, the heat transfer property between exhaust gas etc. and a nitrogen oxide adsorbent improves, and the heat retention or temperature rising effect of a nitrogen oxide adsorbent improves.

  According to a fourth aspect of the present invention, in the exhaust gas purifying apparatus according to the second aspect, a swirl flow forming blade for swirling the exhaust gas flowing in the downstream exhaust passage is disposed in the downstream exhaust passage. .

  According to the above configuration, the exhaust gas is swirled in the downstream side exhaust passage having an annular cross section, and the flow distribution is made uniform, so that the entire nitrogen oxide adsorbent can be kept warm or heated evenly and efficiently. can do. In particular, when the internal combustion engine is operated at a low load, the amount of exhaust gas decreases. However, by rotating the exhaust gas in the downstream side passage as described above, the heat amount of a small amount of exhaust gas can be efficiently consumed without waste. It can be used for heating.

[First Embodiment of the Invention]
FIG. 1 is a first embodiment of an exhaust gas purification apparatus according to the present invention, and the exhaust gas purification apparatus is provided in an exhaust passage of an internal combustion engine 1 or combustion equipment. Examples of the internal combustion engine 1 include a diesel engine, a gas engine, a gasoline engine, and a gas turbine engine, and examples of the combustion equipment include an industrial boiler.

  The outer shell structure of the exhaust passage includes an inner exhaust pipe 2, an outer exhaust pipe 3 surrounding the outer peripheral wall surface of the inner exhaust pipe 2 via an annular space, an extended exhaust pipe 4, and the like. The exhaust upstream end of the inner exhaust pipe 2 is connected to the exhaust port of the internal combustion engine 1, the exhaust upstream end of the outer exhaust pipe 3 is connected to the exhaust downstream end of the inner exhaust pipe 2, and the exhaust of the outer exhaust pipe 3 An extended exhaust pipe 4 is connected to the downstream end.

  The exhaust passage is formed between the upstream exhaust passage 5 formed in the inner exhaust pipe 2, the outer peripheral wall surface of the inner exhaust pipe 2, and the inner peripheral wall surface of the outer exhaust pipe 3. A downstream exhaust passage 6 having an annular cross section that communicates with the downstream end of the exhaust passage 5, an extended exhaust passage 7 that is formed in the extended exhaust pipe 4 and communicates with the exhaust downstream end of the downstream exhaust passage 6, It has.

  A nitrogen oxide adsorbent (hereinafter referred to as “NOx adsorbent”) 10 is disposed in the upstream exhaust passage 5, and an adsorbed substance desorbing means 11 is disposed on the exhaust upstream side of the NOx adsorbent 10. ing. A combustion device 12 is disposed at a position facing the exhaust downstream end of the upstream exhaust passage 5 at the exhaust upstream end 6 a of the downstream exhaust passage 6.

  2 is an enlarged cross-sectional view taken along the line II-II of FIG. 1, and clearly shows a double-pipe structure of an inner exhaust pipe 2 having a circular cross section and an outer exhaust pipe 3 having a circular cross section.

(Configuration of NOx adsorbent 10)
In FIG. 1, the NOx adsorbent 10 can adsorb nitrogen oxides (hereinafter referred to as “NOx”) efficiently even in an excess air atmosphere, and when the temperature is raised to a predetermined temperature or in a reducing atmosphere. It has the property of desorbing the adsorbed NOx. In this embodiment, the NOx adsorbent 10 includes a catalyst having an oxidizing action, and oxidizes unburned components such as carbon monoxide (hereinafter referred to as “CO”) and hydrocarbons (hereinafter referred to as “HC”). The shape of the nitrogen oxide adsorbing material 4 itself is a shape suitable for capturing particulate matter.

  The NOx adsorbent 10 is provided with a NOx adsorption amount detection sensor 29 that detects that the NOx adsorption amount has reached a predetermined amount (for example, a saturation amount or an amount less than the saturation amount) and sends a detection signal to the ECU 23. .

(Composition of combustion device 12)
In FIG. 1, the combustion device 12 includes a fuel nozzle 16 as a fuel supply unit, an ignition device 17 as an ignition unit, and an air supply unit 15. The fuel nozzle 16 is connected to a fuel tank 21 via a fuel metering device 20, and a fuel supply amount and supply timing are controlled by an electronic control unit (hereinafter referred to as “ECU”) 23. The air supply unit 15 is connected to an air supply source 26 via an air metering device 25, and the air metering device 25 is controlled by the ECU 23 to supply and stop air and to control its supply amount.

(Configuration of the adsorbed substance desorbing means 11)
In FIG. 1, the adsorbed substance desorbing means 11 includes an adsorbed substance desorbing fuel nozzle (burner) 31, an adsorbed substance desorbing ignition device 32, and an air supply unit 33. The fuel nozzle 31 is connected to the fuel tank 21 via the fuel metering device 20, and the fuel supply amount and the supply timing are controlled by the ECU 23. The air supply unit 33 is connected to the air supply source 26 via the air metering device 25, and the air metering device 25 is controlled by the ECU 23 to supply and stop air and to control its supply amount.

(Function)
(1) During normal operation of the internal combustion engine 1 or the like, the adsorbed substance desorbing means 11 and the combustion device 12 are stopped. The exhaust gas discharged from the internal combustion engine 1 or the like first flows into the upstream exhaust passage 5, and NOx in the exhaust gas is adsorbed by the NOx adsorbent 10. The exhaust gas from which NOx has been removed flows from the upstream exhaust passage 5 into the exhaust upstream end portion 6a of the downstream exhaust passage 6, and diffuses and turns outward in the radial direction at the exhaust upstream end portion 6a. It flows in the downstream exhaust passage 6 along the outer peripheral wall surface of the inner exhaust pipe 2.

(2) When the exhaust gas in the downstream exhaust passage 6 passes through the outer peripheral wall surface of the inner exhaust pipe 2 where the NOx adsorbent 10 is located, heat exchange is performed between the exhaust gas and the NOx adsorbent 10, and NOx The adsorbent 10 is kept warm. Thereby, the fall of NOx adsorption amount can be suppressed. Note that unburned components such as hydrocarbons and carbon monoxide in the exhaust gas are oxidized and rendered harmless by, for example, a catalyst having an oxidizing action contained in the NOx adsorbent 10.

(3) The exhaust gas that has passed through the downstream exhaust passage 6 and has flowed into the extended exhaust passage 7 is released to the atmosphere or supplied to waste heat utilization equipment.

(4) When the NOx adsorption amount by the NOx adsorbent 10 reaches a predetermined amount after operating for a predetermined time, a detection signal from the NOx adsorption amount detection sensor 29 is sent to the ECU 23, and the adsorbed substance desorbing means is transmitted by a signal from the ECU 23. 11 and the fuel device 12 are operated. That is, a desorption operation (regeneration operation) state is set.

  During the desorption operation, for example, in the adsorbed material desorbing means 11, the fuel from the fuel nozzle 31 and the exhaust gas are mixed and burned with residual oxygen in the exhaust gas and air from the air supply unit 33 to raise the temperature. At the same time, a reducing atmosphere is created and the heated reducing gas is supplied to the NOx adsorbent 10. Thereby, NOx is desorbed from the NOx adsorbent 10. That is, the NOx adsorbent 10 is regenerated. The desorbed NOx is reduced and removed by the catalytic component in the NOx adsorbent 10 in a reducing atmosphere generated by the adsorbed substance desorbing means 11 and is burned in the combustion device 12 to be reduced and removed.

  As described above, during the operation of the internal combustion engine 1 or the like, the desorption operation for desorption of NOx is intermittently performed.

(Effects of the first embodiment)
(1) According to this embodiment, during normal operation of the internal combustion engine 1, the NOx adsorbent 10 is kept warm by the heat of the exhaust gas after passing through the NOx adsorbent 10, so that a decrease in the NOx adsorption amount is suppressed. be able to.

(2) During the desorption operation, the NOx adsorbent 10 is heated by the combustion gas that has been burned in the combustion device 12 and heated, so that the NOx desorption efficiency is improved, the NOx reduction rate, and the energy consumption during NOx regeneration. The rate can be improved.

(3) The outer structure of the exhaust passage is a double-pipe structure of the inner exhaust pipe 2 and the outer exhaust pipe 3, and the NOx adsorbent is generated by the exhaust gas or the combustion gas flowing through the downstream exhaust passage 6 in the outer exhaust pipe 3. 10 can be kept warm or heated, so that the compactness of the exhaust device and the exhaust gas purifying device can be maintained, and the entire NOx adsorbent 10 can be kept warm or evenly heated from the outer peripheral side.

[Second Embodiment of the Invention]
FIG. 3 is a schematic view showing a second embodiment of the present invention, and FIG. 4 is an enlarged sectional view taken along the line IV-IV of FIG. 3. The second embodiment is the same as the first embodiment. The structure includes heat exchange fins 40. Other structures are the same as those of the first embodiment, and the same components are denoted by the same reference numerals.

  In FIG. 3, the plurality of heat exchange fins 40 are provided on the outer peripheral wall surface of the inner exhaust pipe 2 where the NOx adsorbent 10 is disposed so as to extend in the inner exhaust pipe length direction (exhaust flow direction), It is exposed in the downstream exhaust passage 6.

  In FIG. 4, the heat exchange fins 40 are arranged on the outer peripheral wall surface of the inner exhaust pipe 2 at a predetermined interval in the circumferential direction.

  As in the second embodiment, when a large number of heat exchange fins 40 are provided for keeping the temperature of the NOx adsorbent 10 or increasing the temperature, heat transfer between the exhaust gas or the combustion gas and the NOx adsorbent 10 is achieved. And the heat retention effect or temperature rise effect of the NOx adsorbent 10 is improved.

  FIG. 5 shows a modification of the heat exchange fin 40, which has a structure in which a plurality of ring-shaped disks are arranged at intervals in the exhaust flow direction.

[Third Embodiment of the Invention]
FIG. 6 is a schematic view showing a third embodiment of the present invention. In the third embodiment, a swirling flow is generated in the exhaust gas or the like in the same structure as the first embodiment. The swirl flow forming blades 50 are provided. Other structures are the same as those of the first embodiment, and the same components are denoted by the same reference numerals.

  In FIG. 6, the swirl flow forming blade 50 is exhausted from a portion near the exhaust upstream end of the downstream exhaust passage 6 having an annular cross section and facing the outer peripheral wall surface of the inner exhaust pipe 2 where the NOx adsorbent 10 is located. Arranged upstream. That is, the exhaust gas or the combustion gas that has turned into the swirl flow by passing through the swirl flow forming blades 50 is disposed so as to pass through a portion corresponding to the outer peripheral wall surface of the NOx adsorbent 10.

  FIG. 7 is a development view of the swirl flow forming blade 50 of FIG. 6. The swirl flow forming blade 50 is arranged in the same circumferential direction at a predetermined angle with respect to the length direction of the outer exhaust pipe 3 and the inner exhaust pipe 2. Inclined and arranged at equal intervals in the circumferential direction, the exhaust gas passing between the swirl flow forming blades 50 is redirected to form a swirl flow.

  As in the third embodiment, the exhaust gas or the like in the downstream side exhaust passage 6 that keeps the temperature of the NOx adsorbent 10 warm or warmed is swirled to make the flow distribution uniform, thereby making the entire NOx adsorbent 10 uniform. Can be kept warm or heated more efficiently and substantially evenly. In particular, when the internal combustion engine 1 is operated at a low load, the amount of exhaust gas decreases. By turning the exhaust gas as described above, the heat amount of a small amount of exhaust gas can be efficiently used for heat insulation or the like without waste. be able to. Of course, even during the desorption operation, by turning the combustion gas in the downstream side exhaust passage 6, even a small amount of combustion gas can be efficiently used for raising the temperature.

[Other embodiments]
(1) When the internal combustion engine itself is a lean combustion internal combustion engine and is provided with, for example, a supercharger, use the air of the compressor of the supercharger for each air supply unit in FIG. Can do.

(2) As the NOx adsorbent 10, it is possible to use a NOx adsorbent using a NOx adsorbent on the wall of the particulate filter.

(3) In the first, second, and third embodiments, the present invention is applied to a structure having a single exhaust passage. However, the exhaust passage is branched into, for example, two branch exhaust passages. An exhaust gas purification apparatus that includes an adsorption substance desorption means, a nitrogen oxide adsorbent, and a combustion device for each exhaust passage, and alternately performs an adsorption operation and a desorption operation in each branch exhaust passage during operation of the internal combustion engine. It is possible to apply the present invention. Of course, the present invention can also be applied to a structure in which the exhaust passage is branched into three or more branch exhaust passages.

INDUSTRIAL APPLICABILITY The present invention is used as an exhaust gas purification device for various internal combustion engines such as diesel engines, gas engines, gasoline engines or gas turbine engines, or combustion equipment such as industrial boilers. As described above, it is suitable for an internal combustion engine containing a large amount of NOx in the exhaust gas.

1 is a schematic view showing a first embodiment of an exhaust gas purification apparatus according to the present invention. It is the II-II cross-sectional enlarged view of FIG. It is the schematic which shows 2nd Embodiment of the exhaust-gas purification apparatus by this invention. FIG. 4 is an enlarged sectional view taken along the line IV-IV in FIG. 3. FIG. 4 is an enlarged cross-sectional view taken along the line IV-IV in FIG. 3 provided with a modification of the heat exchange fin. It is the schematic which shows 3rd Embodiment of the exhaust-gas purification apparatus by this invention. It is an expanded view of the swirl | vortex flow formation blade | wing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Inner exhaust pipe 3 Outer exhaust pipe 5 Upstream exhaust passage 6 Downstream exhaust passage 10 Nitrogen oxide adsorbent (NOx adsorbent)
DESCRIPTION OF SYMBOLS 11 Adsorbed substance desorption means 12 Combustion apparatus 15 Air supply part 16 of a combustion apparatus Fuel nozzle (fuel supply part) of a combustion apparatus
17 Ignition device (ignition part) of combustion device
23 Electronic Control Unit 31 Fuel Nozzle for Adsorbent Release Unit (Fuel Supply Unit)
32 Ignition device for adsorbing substance desorption means (ignition part)
33 Air supply part of adsorbent desorption means

Claims (4)

An exhaust gas purifying device installed in an exhaust passage of an internal combustion engine or combustion equipment, which temporarily adsorbs nitrogen oxides and adsorbs the adsorbed nitrogen oxides in a temperature rising or reducing atmosphere. Material, an adsorbent detachment means disposed on the exhaust upstream side of the nitrogen oxide adsorbent, and bringing the exhaust gas to a temperature rising or reducing atmosphere; and a fuel supply disposed on the exhaust downstream side of the nitrogen oxide adsorbent An exhaust gas purifying apparatus comprising: a combustion device having a section, an air supply section, and an ignition section.
The exhaust passage includes an upstream exhaust passage in which at least the adsorbed substance desorbing means and the nitrogen oxide adsorbing material are disposed, and exhaust gas that has passed through the combustion device, the nitrogen oxide adsorption of the upstream exhaust passage. An exhaust gas purification apparatus comprising: a downstream exhaust passage that leads to an outer peripheral wall surface of a portion where the material is located. The exhaust gas purification apparatus according to claim 1,
The upstream exhaust passage is formed in an inner exhaust pipe connected to an internal combustion engine or a combustion device, and the downstream exhaust passage connects an outer peripheral wall surface of the inner exhaust pipe and the inner exhaust pipe via an annular space. An exhaust gas purifying device, characterized in that it is formed between an outer peripheral wall surface of an outer exhaust pipe surrounding from the outside. The exhaust gas purification apparatus according to claim 2,
An exhaust gas purifying apparatus, wherein a heat exchange fin exposed in the downstream exhaust passage is provided on an outer peripheral wall surface of an inner exhaust pipe where the nitrogen oxide adsorbent is located. The exhaust gas purification apparatus according to claim 2,
A swirl flow forming blade for swirling exhaust gas flowing in the downstream exhaust passage is disposed in the downstream exhaust passage.

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