JP2005155404A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for internal combustion engine excellent in exhaust emission control performance and capable of being suitably arranged in a limited arrangement space. <P>SOLUTION: The exhaust emission control device 1 is provided with both of DPF13 and urea NOx removal catalyst 23 to materialize collection of particulate matter in exhaust gas and reduction of NOx simultaneously. The DPF 13 and the urea NOx removal catalyst 23 are arranged in parallel (flow of exhaust gas is in series) and are communicated to a communication chamber 30 to form a whole exhaust emission control device 1 in a U-shape. Consequently, longitudinal length can be shortened and the device 1 is made compact as compared with conventional device having those on straight line. Consequently, an arrangement space can be small, the exhaust emission control device 1 can be efficiently arranged in the limited arrangement space and can be suitably used for a construction machine or the like of which vehicle length is not long. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust gas purification device for an internal combustion engine, and more particularly to an exhaust gas purification device for an internal combustion engine that is provided in an exhaust passage of the internal combustion engine and purifies the exhaust gas.

  Conventionally, in order to collect particulates (particulate matter) in exhaust gas discharged from an internal combustion engine such as a diesel engine or to reduce the amount of NOx, an exhaust gas purification device has been installed in the exhaust passage of the internal combustion engine. It is known to provide.

  As an exhaust gas purification device for collecting particulates, an exhaust gas purification device having a diesel particulate filter (hereinafter referred to as DPF (Diesel Particulate Filter)) has been developed. As a purification device, a device equipped with a DeNOx catalyst such as a NOx reduction catalyst or a NOx storage reduction catalyst has been developed.

  In recent years, exhaust gas regulations have become more stringent, and in order to respond to this, an exhaust gas purification device in which a DPF and a DeNOx catalyst are combined in series has been proposed (for example, Patent Document 1). According to such an exhaust gas purification device, for example, particulates can be collected by the DPF in the upstream upstream stage, and NOx can be reduced by the DeNOx catalyst in the downstream downstream stage. It is possible to further improve the purification performance.

JP 2000-199423 A (FIG. 1 etc.)

  However, in the exhaust gas purifying apparatus described in Patent Document 1, since the DPF and the DeNOx catalyst are accommodated in series in a straight pipe body, the entire body is a long body. However, in the case of construction machines such as hydraulic excavators and bulldozers, the placement space is limited. There is a problem that it cannot be arranged well.

  An object of the present invention is to provide an exhaust gas purifying device for an internal combustion engine that is excellent in exhaust gas purifying performance and can be arranged in a limited arrangement space.

  An exhaust gas purification apparatus for an internal combustion engine according to claim 1 of the present invention is disposed downstream of the first post-treatment device and the first post-treatment device disposed upstream of the exhaust gas flow direction of the internal combustion engine. And a communication chamber that communicates the outlet of the first post-treatment device and the inlet of the second post-treatment device, and the first and second post-treatment devices and the communication chamber are connected to the It is formed in a letter shape.

  An exhaust gas purification device for an internal combustion engine according to claim 2 of the present invention is the exhaust gas purification device for an internal combustion engine according to claim 1, wherein the exhaust gas inlet pipe provided on the first aftertreatment device side is The exhaust gas is attached so that the exhaust gas flows in from a direction substantially perpendicular to the flow direction of the exhaust gas in the first aftertreatment device.

  An exhaust gas purification device for an internal combustion engine according to claim 3 of the present invention is the exhaust gas purification device for an internal combustion engine according to claim 1 or 2, wherein the exhaust gas purification device provided on the second aftertreatment device side is provided. The outlet pipe is attached so that the exhaust gas flows out from a direction substantially perpendicular to the flow direction of the exhaust gas in the second aftertreatment device.

  An exhaust gas purification apparatus for an internal combustion engine according to a fourth aspect of the present invention is the exhaust gas purification apparatus for an internal combustion engine according to any one of the first to third aspects, wherein an inlet side of the first aftertreatment device is provided An inlet chamber into which the exhaust gas once enters is provided, and an outlet chamber into which the exhaust gas temporarily enters is provided on the outlet side of the second aftertreatment device. These inlet chamber, outlet chamber, the first aftertreatment device, and the second aftertreatment device. The post-processing device and the communication chamber are separate from each other and are detachable from each other.

  An exhaust gas purification device for an internal combustion engine according to claim 5 of the present invention is the exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 4, wherein the first aftertreatment device is a diesel particulate filter. The second post-treatment device includes a DeNOx catalyst.

  An exhaust gas purification apparatus for an internal combustion engine according to claim 6 of the present invention is the exhaust gas purification apparatus for an internal combustion engine according to claim 5, wherein the DeNOx catalyst is a urea denitration catalyst using urea as a reducing agent, Is provided in the vicinity of the outlet of the first post-processing apparatus.

  An exhaust gas purification device for an internal combustion engine according to claim 7 of the present invention is the exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 6, wherein the second aftertreatment device of the communication chamber is The inlet side is characterized in that the flow path area is reduced toward the inlet.

  An exhaust gas purification apparatus for an internal combustion engine according to an eighth aspect of the present invention is the exhaust gas purification apparatus for an internal combustion engine according to any one of the first to seventh aspects, wherein the second aftertreatment device of the communication chamber is the second exhaust gas purification apparatus. A flow guide for guiding the flow of exhaust gas in the communication chamber to the inlet is provided on a surface facing the inlet.

  An exhaust gas purification device for an internal combustion engine according to claim 9 of the present invention is the exhaust gas purification device for an internal combustion engine according to any one of claims 1 to 8, wherein the exhaust gas purification device in the communication chamber has a flow direction. A perforated plate having a large number of holes is provided at an intermediate position.

  An exhaust gas purification apparatus for an internal combustion engine according to a tenth aspect of the present invention is the exhaust gas purification apparatus for an internal combustion engine according to the ninth aspect, wherein a heater for heating the perforated plate is provided.

  An exhaust gas purification apparatus for an internal combustion engine according to an eleventh aspect of the present invention is the exhaust gas purification apparatus for an internal combustion engine according to any one of the first to tenth aspects, wherein the first aftertreatment device of the communication chamber is the The outlet side is characterized in that the flow path area increases as the distance from the outlet increases.

  According to the exhaust gas purification apparatus of the first aspect of the present invention, by providing both the DPF and the DeNOx catalyst, it is possible to collect particulates in the exhaust gas and to reduce NOx, and to have excellent exhaust gas purification performance. It will be. In addition, the first and second aftertreatment devices are arranged in parallel (the exhaust gas flow is in series), and these are communicated in the communication chamber, so that the entire exhaust gas purification device has a U-shape. 2 The length in the longitudinal direction is shorter than in the conventional arrangement in which the post-processing devices are arranged on a straight line, and the apparatus becomes compact. Therefore, the arrangement space may be small, and the exhaust gas purification device is efficiently arranged in a limited arrangement space.

  According to the second and third aspects of the invention, the inlet pipe and the outlet pipe are attached from the direction substantially perpendicular to the flow direction of the exhaust gas in the first and second post-treatment devices, so that the length in the longitudinal direction is long. Therefore, the exhaust gas purification device is more compactly arranged.

  According to the invention of claim 4, since the first and second post-treatment devices and the portions forming the respective chambers are detachable from each other, the first and second post-treatment devices can be cleaned by disassembling them. It becomes easy and has excellent maintainability.

  According to the invention of claim 5, since DPF is used for the upstream first post-treatment device, there is no fear of clogging with the DeNOx catalyst used for the second downstream post-treatment device, and the original performance of the DeNOx catalyst. Is surely demonstrated. In addition, when an oxidation catalyst is disposed upstream of the DPF or the self-combustion of the collected particulates is promoted by supporting the oxidation catalyst on the DPF itself, in the oxidation catalyst, the monoxide in the exhaust gas is oxidized. Nitrogen (NO) is oxidized into nitrogen dioxide (NO2), and surplus nitrogen dioxide that is not used for self-combustion flows downstream and acts effectively in a DeNOx catalyst such as a urea denitration catalyst. The purification efficiency with the catalyst is improved.

  According to the invention of claim 6, since the urea denitration catalyst is used as the DeNOx catalyst, the NOx purification efficiency is good. Since the urea supply section is provided in the vicinity of the outlet of the first post-treatment device, a sufficient distance is ensured until the urea reaches the urea denitration catalyst, during which urea is reliably heated by the exhaust gas. The For this reason, the decomposition reaction of urea into ammonia is promoted, and NOx purification with the urea denitration catalyst is performed more efficiently.

  According to the invention of claim 7, on the inlet side of the communication chamber to the second post-treatment device, the flow path area is reduced toward the inlet, so that exhaust gas is concentrated on the inlet of the second post-treatment device. As a result, the exhaust gas is efficiently processed by the second post-treatment device, and the purification efficiency is further improved.

  According to the invention of claim 8, since the flow guide is provided on the surface of the communication chamber facing the inlet of the second aftertreatment device, the distribution of the exhaust gas flow is arranged from the front side of the inlet of the second aftertreatment device. As the gas uniformly enters the second post-treatment device, the purification efficiency is improved. Further, since there is no possibility that exhaust gas flows into only a part of the second post-treatment device, thermal stress is unlikely to occur, and the durability of the second post-treatment device is improved.

  According to the ninth aspect of the present invention, since the porous plate functions as an evaporating dish by providing the porous plate in the communication chamber, the reducing agent such as urea touching the porous plate evaporates well into the exhaust gas. It is surely diffused and the purification in the second aftertreatment device is promoted. Furthermore, when urea is used as the reducing agent, decomposition into ammonia is promoted by evaporating urea with a perforated plate.

  According to the invention of claim 10, even when the temperature of the exhaust gas is low and the porous plate is hardly heated by the exhaust gas, the heater is forcibly heated, so that evaporation of the reducing agent is promoted.

  According to the invention of claim 11, in the communication chamber, on the outlet side of the first post-treatment device, the flow passage area increases as the distance from the outlet increases, so the exhaust gas smoothly stagnates toward the second post-treatment device side. It will flow without. Further, since the exhaust gas flows smoothly, when the reducing agent is supplied, the reducing agent is easily mixed into the exhaust gas.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an entire exhaust gas purification apparatus 1 for an internal combustion engine according to the present embodiment, and FIG. 2 is an exploded perspective view thereof. Note that a diesel engine is mainly assumed as the internal combustion engine in the present embodiment.

  The exhaust gas purification device 1 is provided in the exhaust passage of a diesel engine, and is a device for collecting particulates contained in the exhaust gas and reducing NOx emissions into the atmosphere. Also serves as an exhaust muffler. Moreover, such an exhaust gas purification device is suitably mounted on construction machines such as a hydraulic excavator, a bulldozer, and a wheel loader.

  Specifically, the exhaust gas purification device 1 includes an upstream first post-treatment device 10 that collects particulates, a downstream second post-treatment device 20 that purifies and renders NOx harmless, and a first post-treatment. A communication chamber 30 is provided for communicating the outlet 10B of the apparatus 10 and the inlet 20A side of the second post-processing apparatus 20. The overall shape of the exhaust gas purification device 1 is such that the first post-treatment device 10 and the second post-treatment device are provided with substantially the same length and are parallel to each other, and these outlet 10B and inlet 20A. Are communicated in the communication chamber 30 to form a substantially U shape in plan view. However, the exhaust gas flows in series in the order of the first post-treatment device 10, the communication chamber 30, and the second post-treatment device 20 (see the arrows in FIG. 1).

  In addition, the exhaust gas purification device 1 includes an inlet chamber 40 disposed upstream of the first post-treatment device 10, a first auxiliary device 50 disposed between the communication chamber 30 and the second post-treatment device 20, A second auxiliary device 60 disposed on the downstream side of the second post-processing device 20 and an outlet chamber 70 disposed on the further downstream side of the second auxiliary device 60 are provided. Below, each apparatus 10,20,50,60 and each chamber 30,40,70 are explained in full detail.

The first post-processing apparatus 10 has a configuration in which a cylindrical DPF 13 is built in a cylindrical case 11 via a buffer member 12.
Among these, the DPF 13 has a structure in which a large number of small holes are arranged in a honeycomb shape, although detailed illustration is omitted. The small holes communicate from the inflow side end surface 13A toward the outflow side end surface 13B, that is, along the axial direction, and the cross section thereof is formed in a polygonal shape (for example, a hexagonal shape). As the small holes, those that are opened at the inflow side end surface 13A and closed at the outflow side end surface 13B and those that are closed at the inflow side end surface 13A and opened at the outflow side end surface 13B are alternately arranged. The exhaust gas flowing in from the small holes passes through the boundary wall, passes through the small holes, and flows out downstream. Particulates are collected at the boundary wall. The material of such a DPF 13 is made of ceramics such as cordierite and silicon carbide, or metals such as stainless steel and aluminum, and is appropriately determined according to the application.

  Furthermore, the oxidation catalyst is coated on the DPF 13 by a wash coat or the like. The oxidation catalyst here oxidizes nitrogen monoxide in the inflowing exhaust gas to generate nitrogen dioxide. The generated nitrogen dioxide is unstable in a high-temperature atmosphere such as exhaust gas, and releases oxygen and returns to carbon monoxide. However, it is continuously captured by the DPF 13 due to the oxidizing power of the released oxygen. The collected particulates are burned one by one, and the DPF 13 is regenerated to a state where clogging is not always occurring. Further, the nitrogen dioxide that has not returned to the nitric oxide reaches the second post-treatment device 20.

The second post-treatment device 20 has a configuration in which a urea denitration catalyst (DeNOx catalyst) 23 is built in a similar case 21 via a buffer member 22.
Of these, the urea denitration catalyst 23 is made of a base metal such as zeolite or vanadium, reacts ammonia obtained from urea as a reducing agent with NOx in the exhaust gas, and decomposes and purifies NOx into nitrogen and oxygen. . At this time, the urea denitration catalyst 23 is divided into an upstream laminated body 24 and a downstream laminated body 25, and a turbulent flow is generated in the exhaust gas flow in the gap 26 between them, causing a stirring state. The reaction is promoted.

  The communication chamber 30 is formed by a case 31 opened to the first and second post-processing apparatuses 10 and 20 side. A plate 32 is disposed in the opening so as to be sandwiched between the first auxiliary device 50 on the first post-processing device 10 and the second post-processing device 20 side. Here, the plate 32 is provided with a pair of openings 33 and 34, and a flow path in the communication chamber 30 is secured by the plate 32, and the exhaust gas flowing out from the outlet 10 </ b> B of the first post-treatment device 10 is in the middle. The inlet 50A of the first auxiliary device 50 is reached without leaking out.

  Inside the case 31, on the inlet 50A side of the first auxiliary device 50 (same as the inlet 20A side of the second post-processing device 20), the downstream side rectifying plate is arranged so that the flow path area decreases toward the inlet 50A. A plurality of (this embodiment) extended along the flow direction (axial direction) of the exhaust gas in the second post-treatment device 20 on the surface of the downstream rectifying plate 35 facing the inlet 50A. In this case, four flow guides 36 are attached. The downstream flow straightening plate 35 and the flow guide 36 consolidate the flow of the exhaust gas and smoothly change it on the inlet 50 </ b> A side so that the exhaust gas flows into the first auxiliary device 50 and the second post-treatment device 20. The flow distribution at the time is made uniform.

Further, a porous plate 38 is provided upstream of the downstream rectifying plate 35 in a direction against the flow of exhaust gas. The perforated plate 38 is made of a so-called punching metal and has a large number of holes 38A. The exhaust gas flows through the communication chamber 30 through these holes 38A.
An upstream rectifying plate 39 is provided on the upstream side of the porous plate 38 and on the outlet 10B side to the first post-processing device 10 so that the flow path area increases as the distance from the outlet 10B increases. . The upstream rectifying plate 39 also adjusts the flow direction of the exhaust gas, and the flow of the exhaust gas flowing out from the outlet 50B is changed smoothly on the porous plate 38 side.

By the way, in this embodiment using the urea denitration catalyst 23 in the second post-treatment device 20, a reducing agent supply device 80 for injecting urea is attached to the case 31. The reducing agent supply device 80 includes a tank 81 that stores urea, a pump 82 that pumps urea in the tank 81, a filter 83 that removes dust and dirt in the pumped urea, and an injection device that injects urea into the communication chamber 30. The supply unit 84 is provided near the outlet 10 </ b> B of the first post-processing apparatus 10. The urea sprayed from the supply unit 84 evaporates until a part of the urea is applied to the porous plate 38, but the other part is in contact with the porous plate 38 and heated by the exhaust gas. Evaporates above and diffuses into the exhaust gas.
Further, a heater 90 using a heating wire or the like is attached to the perforated plate 38. When the temperature of the exhaust gas is low and the perforated plate 38 is difficult to be heated, the perforated plate 38 is heated by the heater 90, and urea is heated. Encourage evaporation.

  On the other hand, the inlet chamber 40 is a space into which exhaust gas from a turbocharger or the like once enters, and is formed by a bottomed cylindrical case 41 that opens to the inlet 10A side of the first post-processing device 10. On the peripheral surface of the case 41, an inlet pipe 42 for allowing exhaust gas from the turbocharger side to flow into the inlet chamber 40 is provided. The inlet pipe 42 is provided on the peripheral surface of the case 41, thereby drawing the exhaust gas from a direction substantially perpendicular to the flow direction of the exhaust gas in the first aftertreatment device 10. The inlet pipe 42 has a length that traverses the inner space of the inlet chamber 40 in the radial direction. A large number of holes 42A are formed in the peripheral surface of the inlet pipe 42 so that the exhaust gas in the inlet pipe 42 is discharged. The hole 42A extends almost uniformly into the inlet chamber 40. Thereby, in the inlet chamber 40, the flow direction of the exhaust gas flowing in from the radial direction is changed.

The first auxiliary device 50 has a configuration in which a hydrolysis catalyst 53 is built in a cylindrical case 51 via a buffer member 52.
Among these, the hydrolysis catalyst 53 has a function of decomposing urea supplied into the communication chamber 30 to generate ammonia. Then, the ammonia generated here is used for the reaction in the downstream urea denitration catalyst 23.

  Similarly, the second auxiliary device 60 includes a cylindrical case 61, and an oxidation catalyst 63 is built therein via a buffer member 62. The oxidation catalyst 63 here is different in nature from the oxidation catalyst coated on the DPF 13. That is, the oxidation catalyst 63 here oxidizes excess ammonia in the upstream urea denitration catalyst 23 and decomposes it into nitrogen and water to make them harmless.

  The outlet chamber 70 is a space into which the exhaust gas from the second auxiliary device 70 once enters, and is formed by a bottomed cylindrical case 71 opened to the outlet 60 </ b> A side of the second auxiliary device 60. On the peripheral surface of the case 71, an outlet pipe 72 for discharging the exhaust gas from the second auxiliary device 60 into the atmosphere is provided. Since the outlet pipe 72 is provided on the peripheral surface of the case 71, the exhaust gas is discharged in a direction substantially perpendicular to the flow direction of the exhaust gas in the second auxiliary device 60 (same as the post-processing device 10). . That is, also in the outlet chamber 70, the flow direction of the exhaust gas that has flowed in is changed.

  In each of the devices 10, 20, 50, 60 and the chambers 30, 40, 70 described above, the case 11, 21, 31, 41, 51, 61, 71 constituting them is fixed with a fixing bolt (not fixed). Flanges 11A, 21A, 31A, 41A, 51A, 61A, 71A (FIG. 2) are provided, and each can be freely attached and detached by operating bolts and nuts. Is possible.

  At this time, the plate 32 is fixed by inserting bolts for fixing the cases 11, 21, 31 to each other, and fixing to the case 11 in a portion located inside the communication chamber 30. Bolts and bolts that fix the case 21 are inserted. Further, for each fixing, packing or the like of an appropriate material is interposed. In addition, in FIG. 2, illustration of each buffer member 12, 22, 52, 62 is abbreviate | omitted.

  And the above exhaust gas purification apparatus 1 is accommodated in the engine room of a construction machine, for example, is arrange | positioned using the space between an engine and a bonnet by being fixed to the back surface side of a bonnet. As a result, only the outlet pipe 72 is exposed from the bonnet.

According to this embodiment, there are the following effects.
(1) That is, the exhaust gas purification device 1 includes both the DPF 13 in the first post-treatment device 10 and the urea denitration catalyst 23 in the second post-treatment device 20, so that the particulate matter in the exhaust gas Collection and NOx reduction can be realized simultaneously, and the exhaust gas purification performance can be improved.

(2) Further, the first and second post-treatment devices 10 and 20 are arranged in parallel (the exhaust gas flows in series), and these communicate with each other in the communication chamber 30. Since it has a shape, the length in the longitudinal direction can be shortened compared to the conventional arrangement in which the first and second post-processing devices 10 and 20 are arranged in a straight line, and the size can be reduced. Therefore, the arrangement space may be small, the exhaust gas purification device 1 can be efficiently arranged in a limited arrangement space, and can be suitably used for a construction machine or the like in which the length of the vehicle is not long.

(3) The inlet pipe 42 of the inlet chamber 40 and the outlet pipe 72 of the outlet chamber 70 are connected to the cases 41 and 71 from a direction substantially perpendicular to the flow direction of the exhaust gas in the first and second aftertreatment devices 10 and 20. Since the exhaust gas purification device 1 is attached, the length in the longitudinal direction can be further shortened, and the exhaust gas purification device 1 can be reliably disposed in a small space in the engine room.

(4) Since the devices 10, 20, 50, 60 and the chambers 30, 40, 70 are detachable from each other, disassembling them can facilitate cleaning and improve maintainability. it can.

(5) Since the DPF 13 is used for the upstream first post-treatment device 10, there is no fear that the downstream second post-treatment device 20 is clogged with the urea denitration catalyst 23, and the original performance of the urea denitration catalyst 23 is ensured. Can be demonstrated and maintained.

(6) Further, in the present embodiment in which the DPF 13 itself is coated with an oxidation catalyst to promote the self-combustion of the collected particulates, in the oxidation catalyst, nitric oxide in the exhaust gas is oxidized and nitrogen dioxide. Thus, excess nitrogen dioxide that is not used for self-combustion flows downstream and acts effectively in the urea denitration catalyst 23, so that the purification efficiency in the urea denitration catalyst 23 can be improved.

(7) Since the urea denitration catalyst 23 is used as the DeNOx catalyst, the NOx purification efficiency is good. In the reducing agent supply device 80, since the urea supply unit 84 is provided in the vicinity of the outlet 10B of the first post-treatment device 10, a sufficient distance can be secured until the urea reaches the urea denitration catalyst 23. Urea can be reliably heated with exhaust gas. Therefore, the decomposition reaction of urea into ammonia can be promoted, and NOx purification by the urea denitration catalyst 23 can be performed more efficiently.

(8) In the communication chamber 30, the downstream side rectifying plate 35 is provided on the inlet 50A side to the first auxiliary device 50, and the flow passage area decreases toward the inlet 50A. The exhaust gas can be concentrated at the inlet of the second post-treatment device 20. As a result, the exhaust gas can be efficiently processed by the second post-treatment device, and the purification efficiency can be further improved.

(9) Since a plurality of flow guides 36 are provided on the downstream rectifying plate 35, the flow distribution of the exhaust gas can be adjusted from the front side of the inlet 50A of the first auxiliary device 50, and the exhaust gas is supplied with the first auxiliary. It can flow evenly into the device 50 and the second post-treatment device 20, and the purification efficiency can be improved.

(10) On the other hand, the upstream rectifying plate 39 is provided on the outlet 10B side of the first post-processing device 10, and the flow passage area increases as the distance from the outlet 10B increases, so exhaust gas is supplied to the second post-processing device 20 side. It can flow smoothly and smoothly. Further, since the exhaust gas flows without stagnation, the supplied urea and the exhaust gas can be easily and reliably mixed.

(11) Further, since there is no risk of exhaust gas flowing only by a part of the first auxiliary device 50 or the second post-treatment device 20, it is difficult to generate thermal stress, and the first auxiliary device 50 or the second post-treatment device. The durability of 20 can also be improved.

(12) Since the porous plate 38 is provided in the communication chamber 30, the porous plate 38 can function as an evaporating dish, and urea that has touched the porous plate 38 can be vaporized well into the exhaust gas. The purification by the second post-treatment device 20 can be promoted by reliably diffusing.
Further, by evaporating urea with the perforated plate 38, there is an advantage that decomposition into ammonia can be promoted.

(13) Since the heater 90 is connected to the porous plate 38, the heater 90 can be forcibly heated even when the temperature of the exhaust gas is low and the porous plate 38 is difficult to be heated by the exhaust gas. Can promote.

In addition, this invention is not limited to the said embodiment, Including other structures etc. which can achieve the objective of this invention, the deformation | transformation etc. which are shown below are also contained in this invention.
For example, in the second post-treatment device 20 of the above embodiment, the urea denitration catalyst 23 using urea as a reducing agent is used. In addition, a DeNOx catalyst using hydrocarbons (HC) such as fuel as a reducing agent. Or a NOx occlusion reduction catalyst, or other DeNOx catalyst that does not require a reducing agent may be used. When hydrocarbon is used as the reducing agent, instead of the oxidation catalyst 63 for detoxifying ammonia, an oxidation catalyst having another property for oxidizing and detoxifying hydrocarbons is provided downstream of the second aftertreatment device 20. It is necessary to arrange.

  Since the urea denitration catalyst 23 is used in the above embodiment, the hydrolysis catalyst 53 is disposed on the upstream side thereof. However, when urea is sufficiently decomposed into ammonia at the exhaust gas temperature, such hydrolysis is performed. The catalyst 53 may be omitted.

  Although the oxidation catalyst is supported on the DPF 13 in the above embodiment, such an oxidation catalyst may be provided separately from the DPF 13 and arranged upstream thereof.

The best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of quantity, other details, and the like.
Therefore, the description limited to the shape, quantity and the like disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

  The exhaust gas purification apparatus of the present invention can be any industrial machine that uses an internal combustion machine in addition to various construction machines. Also, a vehicle having a long vehicle length can be used in place of the conventional exhaust gas purification device.

1 is a cross-sectional view showing an entire exhaust gas purification apparatus for an internal combustion engine according to an embodiment of the present invention. The exploded perspective view of an exhaust-gas purification apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Exhaust gas purification apparatus, 10 ... 1st aftertreatment apparatus, 10A ... Inlet, 10B ... Outlet, 13 ... Diesel particulate filter, 20 ... 2nd aftertreatment apparatus, 20A ... Inlet, 20B ... Outlet, 23 ... Urea denitration Catalyst (DeNOx catalyst), 30 ... Communication chamber, 36 ... Flow guide, 38 ... Perforated plate, 38A ... Hole, 40 ... Inlet chamber, 42 ... Inlet tube, 70 ... Outlet chamber, 72 ... Outlet tube, 84 ... Supply section, 90: Heater.

Claims (11)

An exhaust gas purification device for an internal combustion engine,
A first aftertreatment device (10) disposed upstream in the flow direction of the exhaust gas of the internal combustion engine;
A second post-processing device (20) disposed downstream of the first post-processing device (10);
A communication chamber (30) for communicating the outlet (10B) of the first aftertreatment device (10) and the inlet (20A) of the second aftertreatment device (20);
An exhaust gas purification device (1) for an internal combustion engine, characterized in that the first and second aftertreatment devices (10, 20) and the communication chamber (30) are formed in an overall U-shape. The exhaust gas purification device (1) for an internal combustion engine according to claim 1,
The exhaust gas inlet pipe (42) provided on the first post-treatment device (10) side allows the exhaust gas to flow from a direction substantially perpendicular to the flow direction of the exhaust gas in the first post-treatment device (10). An exhaust gas purification device (1) for an internal combustion engine, wherein the exhaust gas purification device (1) is attached so as to flow in. In the exhaust gas purification device (1) for an internal combustion engine according to claim 1 or 2,
The exhaust gas outlet pipe (72) provided on the second post-treatment device (20) side allows the exhaust gas to flow from a direction substantially perpendicular to the flow direction of the exhaust gas in the second post-treatment device (20). An exhaust gas purification device (1) for an internal combustion engine, wherein the exhaust gas purification device (1) is attached so as to flow out. The exhaust gas purification device (1) for an internal combustion engine according to any one of claims 1 to 3,
An inlet chamber (40) into which exhaust gas once enters is provided on the inlet (10A) side of the first aftertreatment device (10),
An outlet chamber (70) into which exhaust gas once enters is provided on the outlet (20B) side of the second aftertreatment device (20),
The inlet chamber (40), the outlet chamber (70), the first post-processing device (10), the second post-processing device (20), and the communication chamber (30) are separated and attached to each other. An exhaust gas purifying device (1) for an internal combustion engine, characterized in that it is possible. The exhaust gas purification device (1) for an internal combustion engine according to any one of claims 1 to 4,
The first aftertreatment device (10) includes a diesel particulate filter (13),
The second aftertreatment device (20) includes a DeNOx catalyst. An exhaust gas purification device (1) for an internal combustion engine, characterized in that: The exhaust gas purification device (1) for an internal combustion engine according to claim 5,
The DeNOx catalyst is a urea denitration catalyst (23) using urea as a reducing agent,
An exhaust gas purification device (1) for an internal combustion engine, characterized in that a supply unit (84) for supplying urea is provided in the vicinity of an outlet (10B) of the first aftertreatment device (10). In the exhaust gas purification device (1) for an internal combustion engine according to any one of claims 1 to 6,
The exhaust gas of the internal combustion engine, characterized in that the flow path area of the communication chamber (30) on the inlet (20A) side of the second aftertreatment device (20) is reduced toward the inlet (20A). Purification device (1). The exhaust gas purification device (1) for an internal combustion engine according to any one of claims 1 to 7,
On the surface of the communication chamber (30) facing the inlet (20A) of the second post-treatment device (20), a flow for guiding the flow of exhaust gas in the communication chamber (30) to the inlet (20A). An exhaust gas purification device (1) for an internal combustion engine, characterized in that a guide (36) is provided. The exhaust gas purification device (1) for an internal combustion engine according to any one of claims 1 to 8,
An exhaust gas for an internal combustion engine, characterized in that a porous plate (38) having a large number of holes (38A) is provided at a position midway in the flow direction of the exhaust gas in the communication chamber (30). Purification device (1). The exhaust gas purification device (1) for an internal combustion engine according to claim 9,
An exhaust gas purifying device (1) for an internal combustion engine, wherein a heater (90) for heating the porous plate (38) is provided. The exhaust gas purification device (1) for an internal combustion engine according to any one of claims 1 to 10,
Exhaust gas from an internal combustion engine, characterized in that the flow path area of the communication chamber (30) on the outlet (10B) side of the first aftertreatment device (10) increases as the distance from the outlet (10B) increases. Gas purification device (1).

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