JP2007016706A - Exhaust emission control device and pm continuous regeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device to be mounted in a diesel engine (DE) mounted vehicle for trapping particulate matters (PM) in exhaust gas, and to provide a PM continuous regeneration system. <P>SOLUTION: The exhaust emission control device comprises a plurality of metal carriers each consisting of a matrix portion having a metal structure and a mantle portion welded to the outer periphery of the matrix portion, outer cylinders having the same number as the number of the metal carriers for covering the metal carriers, and a diffuser for introducing exhaust gas from a diesel engine into the metal carriers. The metal carriers are each covered with the outer cylinder to form a heat insulating layer between the mantle portion and the outer cylinder, the mantle portion and the outer cylinder are fixed to each other with a flange, and the metal carrier and the outer cylinder are linearly connected to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exhaust emission control device and a PM continuous regeneration system that are mounted to collect particulate matter (hereinafter referred to as PM) in exhaust gas in a vehicle equipped with a diesel engine (hereinafter referred to as DE).

The emission regulation value of DE that becomes stricter year by year is that carbon dioxide (CO ₂ ) and water (CO ₂ ) are oxidized by oxidizing PM, hydrocarbon (HC) and carbon monoxide (CO) with a catalyst in the same way as a gasoline engine after 2005. H ₂ O), NO _x must be dissociated to make nitrogen (N ₂ ) and oxygen (O ₂ ) harmless, and then discharged.

  Conventionally, DE for automobiles has tried to reduce harmful substances contained in exhaust gas mainly by improving combustion of the engine itself, but it is considered to be very difficult to conform to exhaust emission regulation values after 2005. ing.

Therefore, recently, research and development on a continuously regenerative DPF (Continuously Regenerative Diesel Particulate Filter) composed of a front-stage diesel oxidation catalyst (DOC) and a rear-stage diesel particulate filter (DPF) has been underway. In the preceding DOC, HC changes to CO ₂ and H ₂ O, and CO changes to CO ₂ . Further, nitrogen monoxide (NO) in NO _x is changed to nitrogen dioxide (NO ₂ ). In the latter-stage DPF, the soot component in the PM is burned with NO ₂ generated in the former stage and discharged as CO ₂ . This continuous regenerative DPF is known as a CRT invented by Johnson Mathey. Research and development of an integrated DPF (catalyst-supported DPF) in which various oxidation catalysts are supported on a structure DPF having only a filter function is also underway. In the present invention, a DPF having only a filter function is simply a DPF, and a DPF carrying a catalyst is a catalyst-carrying DPF. In the present invention, the continuous regeneration type DPF includes a catalyst-supporting DPF, a combination of DOC and DPF, and a combination of DOC and catalyst-supporting DPF.

Research and development is also underway for a selective catalyst reduction method (SCR) in which a DeNO _x catalyst is provided in the subsequent stage of the continuous regeneration type DPF and the last remaining NO _x is also dissociated. A device combining this SCR and the above CRT is known as SCRT from Johnson Mathey.

The combustion of PM in the continuous regeneration type DPF is said to be 350 ° C. or more in the catalyst-supporting DPF and 250 to 450 ° C. in the DOC. The exhaust temperature during normal idling of the DE is 70 to 100 ° C. At a traveling speed of 80 km / hr or less of a vehicle driven by the DE, the load of the DE corresponding to the generated traveling resistance is low, and the exhaust temperature is The problem is that PM that does not reach 260 ° C (250 ° C + α) and is collected in the continuously regenerating DPF accumulates in the filter without being regenerated (oxidized), clogs, and eventually becomes impossible to operate. was there.
JP 2002-322909 A JP 2003-293749 A JP 2001-336440 A

  For this reason, in Patent Document 1, in addition to the main catalyst, an auxiliary catalyst having a small heat capacity is installed in the vicinity of the engine, and the main catalyst is used at the time of high output of the engine, and the auxiliary catalyst is used at the time of low output. Avoid cooling by long pipes and avoid lowering the specific output of the engine due to the catalyst being installed close to the engine, and using an auxiliary catalyst with a small heat capacity at the start of the engine will increase the temperature in a short time and activate the catalyst It is possible to do.

  Further, in Patent Document 2, an auxiliary catalyst having a small heat capacity is provided in addition to the main catalyst, and an intake throttle, ESC, reduced cylinder, and exhaust throttle can be performed.

  In the DE low load high exhaust temperature maintenance device described in Patent Documents 1 and 2 and Patent Document 3, if it is a disadvantageous condition such as a low load state for a long time, it accumulates inside the catalyst rather than the PM regeneration capability of the catalyst. There was a problem that the state of exceeding the amount of PM continued and the engine eventually misfired.

  In particular, in a 3.0 liter supercharged engine, the DE high exhaust temperature maintenance device at low load described in Patent Document 3 has succeeded in effective exhaust gas rise and continuous PM regeneration, but has an unfavorable condition. Then PM couldn't be played continuously.

  In DPF, ceramics, cordierite, silicon carbide, silicon nitride and the like are used, but these ceramics and the like have poor thermal conductivity. Therefore, when PM accumulates and regenerative combustion is partially started, heat is not dispersed and heat is partially generated, and the part where the temperature has increased rapidly burns out, and the exhaust gas flows out from there. There was a problem such as.

  In addition, when a metal carrier is used for the DPF, the canning pipe is in direct contact with the outside air, so that the temperature of the canning pipe is cooled by the traveling wind during traveling, so that the temperature of the DPF also decreases and it is difficult to continuously regenerate PM. There was a problem of becoming.

  The present invention has been made under the circumstances described above, and an object of the present invention is to provide an exhaust purification device and a PM continuous regeneration system capable of continuously regenerating (oxidizing) PM even if conditions unfavorable for PM regeneration continue for a long time. Is to provide.

  The present invention is an exhaust emission control device capable of continuously regenerating PM even under unfavorable conditions for PM regeneration for a long time, and an object of the present invention is to provide a matrix portion made of a metal structure, A plurality of metal carriers comprising a mantle portion welded to the outer periphery, the same number of outer cylinders as the metal carriers covering the metal carriers, and a diffuser for introducing exhaust gas discharged from a diesel engine into the metal carriers Each of the metal carriers is covered with the outer cylinder so as to have a heat insulating layer between the mantle part and the outer cylinder, the mantle part and the outer cylinder are fixed with a flange, This is achieved by connecting the metal carrier and the outer cylinder in a straight line.

  The above object of the present invention is such that the diffuser has a double-pipe structure, or the exhaust pipe for sending exhaust gas discharged from a diesel engine to the diffuser protrudes into the diffuser. The thickness of the heat insulating layer formed between the mantle portion and the outer cylinder is 6 to 12 mm, or on the outside of the outer cylinder, the plurality of flanges In the plurality of metal carriers, the metal carrier installed on the diffuser side is a DOC other than the metal carrier installed on the diffuser side. The metal carrier is more effectively achieved by being a DPF or by making all DPF.

  Further, the object of the present invention is that the mantle portion has a mantle protrusion, and is fixed to the flange by the mantle protrusion, or a high temperature seal is provided between the mantle protrusion and the flange. By applying and fixing the agent, or the flange is formed with a groove so that the mantle protrusion fits, and after placing a wire in the groove, the flange is fixed to the mantle protrusion, or By applying and fixing the high temperature sealant between the outer cylinder and the flange, or the flange has a groove formed so that the outer cylinder abuts, and a sealing sheet is placed in the groove. This is achieved more effectively by fixing the outer cylinder and the flange.

  The object of the present invention is to form a plurality of outflow holes in the projecting portion of the exhaust pipe and reduce the cross-sectional area of the exhaust port of the exhaust pipe, or to reduce the total area of the outflow hole and the disconnection of the exhaust port. By adjusting the hole diameter and the number of holes in the cross-sectional area of the outflow hole and the exhaust port so that the sum total with the area is 1.7 to 2.3 times the cross-sectional area of the inner diameter of the exhaust pipe, Effectively achieved.

  Further, the above object of the present invention is to install a first baffle plate having a plurality of holes having the same diameter over the entire surface between the exhaust pipe and the metal carrier in the diffuser. Alternatively, the second baffle plate having a plurality of holes only in the upper half and the diameter of the holes gradually decreasing toward the center of the set of holes is replaced with the first baffle plate. Or in the diffuser by placing the first baffle plate and the second baffle plate between the exhaust pipe and the metal carrier.

  The present invention relates to a PM continuous regeneration method using the above-described exhaust purification device, and an object of the present invention is to provide an exhaust throttle valve in the downstream of the exhaust purification device described above, and to exhaust the exhaust in the upstream of the exhaust purification device. By providing a brake, or by providing only an exhaust brake upstream of the exhaust gas purification device, operating with a multi-stage actuator, and stopping at an intermediate stage, it is also configured to serve as the exhaust throttle valve. Is achieved.

  According to the exhaust emission control device of the present invention, since the outer cylinder is provided to have a double structure and also has a heat insulating layer, heat is not taken away from the metal carrier to the outside air side. As a result, the PM accumulated in the DPF can be efficiently regenerated.

  According to the PM continuous regeneration system of the present invention, when an exhaust brake operated by a multi-stage actuator is provided in front of the exhaust purification device, the exhaust throttle valve can also be used, so that the exhaust throttle valve is closed from the open state. It was also possible to eliminate the diffused sound that occurred when

  Further, in the exhaust purification device and the PM continuous regeneration system of the present invention, since there is no independent piping or the like, the manufacturing cost can be reduced, and the currently used (commercially available) DE and exhaust purification device Even cars with short distances can be retrofitted to DE.

  It is said that the exhaust gas temperature needs to be 260 ° C. or higher in order to regenerate (oxidize) PM with the exhaust purification device. Therefore, in the present invention, the clogging of the filter in the exhaust emission control device is prevented by using a metal carrier having excellent thermal conductivity and providing an outer cylinder and a heat insulating layer that prevent the metal carrier from cooling during traveling. It is characterized by doing. Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

  FIG. 1 is a configuration diagram showing an example of a PM continuous regeneration system using the exhaust purification device of the present invention.

  The air that has passed through the air cleaner 1 passes through the intake throttle valve 2, is sent into the DE3 cylinder (the cylinder is not shown), and is mixed with the fuel injected in the DE3 cylinder and burned. An DEGR system is connected to DE3 and plays a role of returning exhaust gas into DE3 by opening and closing the EGR valve 4 in the EGR system. The combusted exhaust gas passes through the exhaust manifold 5, passes through the exhaust brake 6 and the exhaust pipe 7, and is purified by the exhaust purification device 8. The exhaust gas purified by the exhaust purification device 8 passes through the exhaust throttle valve 9 and is discharged to the discharge port. The closing of the intake throttle valve 2, EGR valve 4, exhaust brake 6 and exhaust throttle valve 9 is controlled by the ECU 10.

  When the exhaust brake 6 is closed, it becomes difficult for the exhaust gas to flow, and the pressure during exhaust in the cylinder of the DE 3 increases. Since DE3 tries to exhaust the exhaust gas from the cylinder against this pressure, the force applied to the piston increases. Since the fuel injection is not performed when the exhaust brake 6 is operating, the force applied to the piston appears as a force to stop DE3, that is, a brake.

  By installing the exhaust purification device 8 between the exhaust throttle valve 9 and the exhaust brake 6, the exhaust purification device 8 can be used as a muffler. Thereby, the diffused sound generated when the exhaust brake 6 changes from the open state to the closed state can be prevented. In addition, by enabling the exhaust brake 6 to be operated by a multi-stage actuator, it is possible to have the same action as the exhaust throttle valve 9 by stopping at an intermediate stage. In this case, the diffused sound can be further reduced by using the exhaust purification device 8 as a muffler for the slight diffused sound generated when the exhaust throttle valve 9 changes from the open state to the closed state.

  It is preferable that the exhaust throttle valve 9 has the same structure as the exhaust brake 6, that is, uses the same thing as the exhaust brake 6. Thereby, cost can be held down.

  FIG. 2 is a view showing the structure of the first embodiment of the exhaust emission control device 8 of the present invention (the arrow in the figure indicates the flow of exhaust gas).

  The exhaust gas discharged from the DE 3 is discharged to the diffuser 11 in the exhaust purification device 8 through the exhaust pipe 7. The exhaust gas diffused into the diffuser 11 is continuously regenerated with PM contained in the exhaust gas by the plurality of metal carriers 12 covered with the outer cylinder 13. The metal carrier 12 and the outer cylinder 13 are connected via a flange 14, and a plurality (three in FIG. 2) of the metal carrier 12 and the outer cylinder 13 are linearly integrated. The exhaust gas in which PM is continuously regenerated by the plurality of metal carriers 12 passes through the reducer 19 and is discharged to the outside via the exhaust throttle valve 9.

  Further, the exhaust purification device 8 falls off the vehicle body due to breakage of a suspension stay (not shown) that fastens the metal carrier 12 and the flange 14, and the nut that fixes the metal carrier 12, the outer cylinder 13, and the flange 14. In order to prevent loosening, two assembly bolts 17 are installed on each flange 14 diagonally with respect to the flange 14 and fixed with double nuts 18. Although not shown, a wire for preventing dropout may be wound around an assembly bolt and fixed to the vehicle body to prevent the exhaust purification device 8 from dropping off.

  The exhaust pipe 7 is connected in a state where the exhaust pipe 7 protrudes into the diffuser 11. By connecting the exhaust pipe 7 so as to protrude into the diffuser 11, the exhaust gas flowing from the exhaust port 71 is easily diffused into the diffuser 11, and PM in the exhaust gas is continuously regenerated by the entire metal carrier 12. be able to. Although details will be described in the second embodiment, an outflow hole may be provided in the exhaust pipe 7 so that the exhaust gas can easily diffuse into the diffuser 11.

  The diffuser 11 plays a role of introducing the exhaust gas discharged from the DE 3 into the metal carrier 12 and is connected to the exhaust pipe 7. The diffuser 11 has a double-pipe structure and prevents the diffuser 11 from being cooled by the traveling wind during traveling and the exhaust gas temperature from being lowered. The material of the diffuser 11 is not particularly limited as long as it can withstand the temperature of the exhaust gas. Further, the shape of the diffuser 11 can be changed as appropriate according to the purpose of use, the method, etc., but PM can be continuously regenerated efficiently with the metal carrier 12 and the exhaust gas can easily diffuse into the exhaust purification device 8. In order to achieve this, a conical shape is preferable. The diffuser 11 is connected to the metal carrier 12 via the gasket 15, and the exhaust gas diffused into the diffuser 11 moves to the metal carrier 12.

  The metal carrier 12 is covered with an outer cylinder 13 and has a structure having a heat insulating layer 16 (air gap) between the metal carrier 12 and the outer cylinder 13. By having the heat insulating layer 16, it is possible to prevent the metal carrier 12 from being cooled during traveling. The heat insulating layer 16 is mainly filled with air.

  A plurality of metal carriers 12 can be installed (FIG. 1 shows a case where three metal carriers 12 are installed for the sake of space), and each metal carrier 12 is covered with one outer cylinder 13. Yes. That is, the same number of metal carriers 12 and outer cylinders 13 are provided. The metal carrier 12 and the outer cylinder 13 are fixed by a flange 14, and the plurality of metal carriers 12 and the outer cylinder 13 are integrated via the flange 14 and connected in a straight line. The plurality of metal carriers 12 may use either DPF or DOC. For example, all of the plurality of metal carriers 12 may be DPF, the metal carrier 12 on the diffuser 11 side (front stream) is DOC, and the like. The metal carrier 12 may be a DPF.

  Although the thickness of the heat insulation layer 16 is suitably changed according to the intended purpose, the usage method, etc. of the exhaust gas purification apparatus 8, it is preferable that it is 6-12 mm. When the thickness of the heat insulating layer 16 is less than 6 mm, the metal carrier 12 is cooled by the traveling wind during traveling, and the PM in the exhaust gas cannot be continuously regenerated. On the other hand, when the thickness of the heat insulating layer 16 exceeds 12 mm, the metal carrier 12 is not cooled by the traveling wind, but the exhaust purification device 8 becomes large and difficult to attach to the vehicle body.

  FIG. 3 is a view showing the structure of the metal carrier 12. The metal carrier 12 includes a matrix portion 121 that collects PM in the exhaust gas and a mantle portion (outer portion) 122 that covers the outer periphery of the matrix portion 121.

  The mantle part 122 plays the role which protects the matrix part 121, and is integrated with the matrix part 121 by welding. The mantle part 122 is a metal cylinder of about 1 to 5 mm and has rigidity. The mantle part 122 has a mantle protruding part 123 and is fixed by the flange 14 by the mantle protruding part 123.

  FIG. 4 is a view showing the structure of the flange 14. The flange 14 has a plurality of connecting bolt holes 141 for fixing the metal carrier 12 and the outer cylinder 13. The metal carrier 12 and the outer cylinder 13 are fixed via the connecting bolt hole 141 every other one. Further, using the remaining connecting bolt hole 141, one metal carrier 12 and the outer cylinder 13 are fixed to the opposite side. By fixing the plurality of metal carriers 12 using the flange 14 in this way, the metal carriers 12 can be connected in a straight line, and PM in the exhaust gas can be continuously regenerated more efficiently. . In FIG. 4, the number of connecting bolt holes 141 is eight (the metal carrier 12 and the outer cylinder 13 are fixed using the four connecting bolt holes 141). Accordingly, the number of connecting bolt holes 141 can be changed as appropriate. For example, the holes 141 may be black holes in FIG. 4 or the holes 141 may be white holes.

  FIG. 5 is a schematic view showing a portion where each metal carrier 12 is connected via the flange 14. Since both end surfaces of the mantle protruding portion 123 are processed, a certain level of surface accuracy is ensured, but since the flatness is not sufficient, exhaust gas may leak from the mantle protruding portion 123 to the heat insulating layer 16. is there. Therefore, in the present invention, the high temperature sealant is applied to the circumference of the mantle protrusion 123 and the flange 14, and then the mantle protrusion 123 and the outer cylinder 13 of the metal carrier 12 are fixed by the flange 14. Although details will be described later, also in the case of fixing the outer cylinder 13, the high-temperature sealant is applied to the outer cylinder 13 and then fixed.

  The type of the high-temperature sealant used in the present invention is not particularly limited as long as it can withstand the heat of the exhaust gas. For example, a high-temperature sealant containing various known components such as an epoxy resin and an elastomer may be used. These may be used alone or in combination with a plurality of high temperature sealants.

  In FIG. 6, FIG. 6A is a cross-sectional view of the flange, and FIG. 6B is a schematic view showing another form of a portion where each metal carrier 12 is connected via the flange 14. In the method shown in FIG. 5, the exhaust gas is prevented from leaking into the heat insulating layer 16 by applying a high temperature sealant to the end face of the mantle protrusion 123, whereas in the method shown in FIG. 14, a groove 142 for abutting only the mantle part 122 is configured, the wire 20 is placed in the groove 142, and the wire 20 is crushed by the mantle part 122, thereby preventing the exhaust gas from leaking into the heat insulating layer 16.

  The wire 20 is preferably made of a soft material such as linear annealed copper. By using such a material, the mantle portion 122 can be uniformly crushed, and the exhaust gas can be effectively prevented from leaking into the heat insulating layer 16.

  FIG. 7 is a schematic view showing a portion where each outer cylinder 13 is connected via a flange 14. As with the mantle protrusion 123, when the outer cylinder 13 is fixed, it is possible to prevent the exhaust gas from leaking to the outside by applying a high-temperature sealant and fixing it, thereby forming a heat insulating region and heat to the outside. Can be prevented.

  FIG. 8 is a schematic view showing another form of a portion where each outer cylinder 13 is connected via a flange 14. In the method shown in FIG. 7, the high temperature sealant is applied to the outer cylinder 13 to prevent the exhaust gas from leaking to the outside. In the method shown in FIG. By forming a groove 142 for abutting only 13, placing a sealing sheet 21 in the groove 142, and crushing the sealing sheet 21 with the outer cylinder 13, exhaust gas is prevented from leaking to the outside.

  The sealing sheet 21 is preferably made of a soft material such as annealed copper. By using such a material, the sealing sheet 21 can be uniformly crushed by the outer cylinder 13, and the exhaust gas can be effectively prevented from leaking to the outside. The sealing sheet 21 may be replaced with the wire 20 according to the purpose of use.

  FIG. 9A is a schematic view showing the structure of the second embodiment of the exhaust emission control device 8 of the present invention. In addition, description is abbreviate | omitted about the location which overlaps with the content mentioned above. In the second embodiment, a baffle plate 22 is provided in the diffuser 11, and the exhaust pipe 7 is provided with a plurality of outflow holes 72 through which the exhaust gas flows out in order to facilitate the diffusion of the exhaust gas in the diffuser 11. The structure is the same as in the first embodiment. The exhaust gas diffuses into the diffuser 11 from the outflow hole 72 and the exhaust port 71 and passes through the baffle plate 22. By passing the exhaust gas through the baffle plate 22, the exhaust gas is prevented from collecting in the center of the diffuser 11, and the temperature inside the diffuser 11 is diffused to introduce the exhaust gas having a uniform temperature over the entire surface of the metal carrier 12. can do.

  FIG. 9 (B) is a view of the exhaust pipe 7 in FIG. 9 (A) taken along the line AA (see the exhaust pipe 7 from the diffuser 11 side). As shown in FIG. 11, the exhaust port 71 of the exhaust pipe 7 has a small cross-sectional area.

  The total area of the outflow holes 72 of the exhaust pipe 7 and the sum of the cross-sectional areas of the exhaust ports 71 are preferably 1.7 to 2.3 times the cross-sectional area of the inner diameter of the exhaust pipe 7. When the cross-sectional area of the inner diameter of the exhaust pipe 7 is less than 1.7 times, the outflow coefficient from the outflow hole 72 (when the fluid flows out of the hole, it becomes a contracted flow and is smaller than the actual cross-sectional area of the hole. This is due to the hydrodynamic situation that only the area is effectively used, which means a value obtained by dividing the actually used cross-sectional area by the geometric cross-sectional area), and the pressure loss resistance increases. On the other hand, when the cross-sectional area of the inner diameter of the exhaust pipe 7 exceeds 2.3 times, the volume of the protruding portion of the exhaust pipe 7 in the diffuser 11 increases, and the flow distribution of the exhaust gas can be formed smoothly. Disappear.

  FIG. 10 is a cross-sectional view of the baffle plate. The baffle plate 22 used in the second embodiment uses either the first baffle plate 23 shown in FIG. 10 (A) or the second baffle plate 24 shown in FIG. 10 (B). Can be changed as appropriate.

  The second baffle plate 24 in FIG. 10B has a plurality of small diameter holes 241 at the center of the second baffle plate 24, and the diameter of the holes 241 increases toward the outside of the second baffle plate 24. ing. By increasing the diameter of the hole 241 toward the outside, the exhaust gas can be prevented from collecting at the center of the metal carrier 12, and the exhaust gas can be introduced uniformly over the entire surface of the metal carrier 12. Further, the hole 241 of the second baffle plate 24 is only on the upper side, and there is no hole 241 at the lower part. By doing in this way, the big soot component in exhaust gas can be dropped and collected in the lower part of the diffuser 11, and it can prevent that the metal support | carrier 12 causes clogging with a big soot component. The soot component deposited on the lower surface of the diffuser 11 is regenerated and burned when high-temperature exhaust gas is introduced.

  The first baffle plate 23 shown in FIG. 10A has a plurality of holes 231 having the same diameter over the entire surface of the first baffle plate 23, and provides the same effect as the second baffle plate 24. .

  FIG. 11 is a schematic view showing the structure of the third embodiment of the exhaust emission control device of the present invention. In addition, description is abbreviate | omitted about the location which overlaps with the content mentioned above. In the third embodiment, the same configuration as that of the second embodiment is adopted except that the first baffle plate 23 and the second baffle plate 24 are provided in the diffuser 11. The first baffle plate 23 has the same shape as that shown in FIG. 10A, and the second baffle plate 24 has the same shape as that shown in FIG. The exhaust gas diffuses into the diffuser 11 from the outflow hole 72 and the exhaust port 71, passes through the second baffle plate 24, and passes through the first baffle plate 23, thereby exhausting the exhaust gas into the center of the diffuser 11. The exhaust gas having a uniform temperature can be introduced to the entire surface of the metal carrier 12 while avoiding the collection of gas.

  The exhaust gas passes through the second baffle plate 24 to make the exhaust gas temperature uniform, and the exhaust gas passes through the first baffle plate 23 to further promote the uniformity of the exhaust gas temperature. In FIG. 11, the exhaust gas discharged from the exhaust pipe 7 first passes through the second baffle plate 24 and then passes through the first baffle plate 23. Then, the second baffle plate 24 may be passed, and the exhaust gas may be introduced into the metal carrier 12. In FIG. 11, the shape of the diffuser 11 is a cylindrical shape, but it may be a conical shape as in the first and second embodiments.

It is a block diagram which shows an example of PM continuous regeneration system which uses the exhaust gas purification apparatus of this invention. It is the figure which showed the structure of 1st Embodiment of the exhaust gas purification apparatus of this invention. It is the figure which showed the structure of the metal carrier used with the exhaust gas purification apparatus of this invention. It is the figure which showed the structure of the flange used with the exhaust gas purification apparatus of this invention. It is the schematic diagram which showed 1st Embodiment of the part which connects each metal support | carrier via a flange. (A) It is sectional drawing of a flange, (B) It is the schematic diagram which showed 1st Embodiment of the part which connects each metal support | carrier via a flange. It is the schematic diagram which showed 1st Embodiment of the part which connects each outer cylinder via a flange. It is the schematic diagram which showed 2nd Embodiment of the part which connects each outer cylinder via a flange. (A) It is the schematic which showed the structure of 2nd Embodiment of the exhaust gas purification apparatus of this invention, (B) The figure which looked at the exhaust pipe from the diffuser side in the state which looked at the AA arrow. . (A) It is sectional drawing of a 1st baffle plate, (B) It is sectional drawing of a 2nd baffle plate. It is the schematic which showed the structure of 3rd Embodiment of the exhaust gas purification apparatus of this invention.

Explanation of symbols

1 Air cleaner 2 Inlet throttle valve 3 Diesel engine (DE)
4 EGR valve 5 Exhaust manifold 6 Exhaust brake 7 Exhaust pipe 71 Exhaust port 72 Outflow hole 8 Exhaust purification device 9 Exhaust throttle valve 10 ECU
11 Diffuser 12 Metal carrier 121 Matrix part 122 Mantle part 123 Mantle protruding part 13 Outer cylinder 14 Flange 141 Connection bolt hole 142 Groove 15 Gasket 16 Heat insulation layer (air gap)
17 Assembly bolt 18 Double nut 19 Reducer 20 Wire 21 Sealing sheet 22 Baffle plate 23 First baffle plate 231 Hole 24 Second baffle plate 241 Hole

Claims (19)

  A plurality of metal carriers composed of a matrix portion made of a metal structure, a mantle portion welded to the outer periphery of the matrix portion, the same number of outer cylinders as the metal carriers covering each metal carrier, and exhaust from a diesel engine Each of the metal carriers is covered with the outer cylinder so as to have a heat insulating layer between the mantle part and the outer cylinder, and the mantle part, An exhaust emission control device, wherein the outer cylinder is fixed with a flange, and the plurality of metal carriers and the outer cylinder are connected in a straight line.   The exhaust purification device according to claim 1, wherein the diffuser has a double pipe structure.   The exhaust emission control device according to claim 1 or 2, wherein an exhaust pipe that sends exhaust gas discharged from the diesel engine to the diffuser is configured to protrude into the diffuser.   The exhaust emission control device according to any one of claims 1 to 3, wherein a thickness of the heat insulating layer formed between the mantle portion and the outer cylinder is 6 to 12 mm.   The exhaust emission control device according to any one of claims 1 to 4, wherein two bolts are connected diagonally through the plurality of flanges outside the outer cylinder.   6. The plurality of metal carriers, wherein the metal carrier installed on the diffuser side is a DOC, and the metal carriers other than the metal carrier installed on the diffuser side are DPFs. An exhaust emission control device according to claim 1.   The exhaust emission control device according to any one of claims 1 to 5, wherein the plurality of metal carriers are all DPF.   The exhaust purification device according to any one of claims 1 to 7, wherein the mantle portion has a mantle protrusion, and is fixed to the flange at the mantle protrusion.   The exhaust emission control device according to any one of claims 1 to 8, wherein a high temperature sealant is applied and fixed between the mantle protrusion and the flange.   The exhaust purification device according to any one of claims 1 to 8, wherein the flange is formed with a groove so that the mantle protrusion is fitted, and is fixed to the mantle protrusion after a wire is placed in the groove.   The exhaust emission control device according to any one of claims 1 to 10, wherein the high temperature sealant is applied and fixed between the outer cylinder and the flange.   The exhaust purification device according to any one of claims 1 to 10, wherein the flange is formed with a groove so that the outer cylinder abuts, and a sealing sheet is placed in the groove to fix the outer cylinder and the flange. .   The exhaust emission control device according to any one of claims 1 to 12, wherein a plurality of outflow holes are formed in a projecting portion of the exhaust pipe to reduce a cross-sectional area of an exhaust port of the exhaust pipe.   The sum of the total area of the outflow hole and the cross-sectional area of the exhaust port is 1.7 to 2.3 times the cross-sectional area of the inner diameter of the exhaust pipe. The exhaust emission control device according to any one of claims 1 to 13, wherein the hole diameter and the number of holes are adjusted.   The first baffle plate having a plurality of holes having the same diameter over the entire surface is installed between the exhaust pipe and the metal carrier in the diffuser. Exhaust purification equipment.   The second baffle plate having a plurality of holes only in the upper half and having a diameter that gradually decreases toward the center of the set of holes is replaced with the first baffle plate. Item 16. The exhaust emission control device according to any one of Items 1 to 15.   The exhaust emission control device according to any one of claims 1 to 14, wherein the first baffle plate and the second baffle plate are installed between the exhaust pipe and the metal carrier in the diffuser.   18. A PM continuous regeneration system comprising an exhaust throttle valve provided downstream of the exhaust purification device according to claim 1 and an exhaust brake provided upstream of the exhaust purification device.   The PM continuous regeneration system according to claim 18, wherein the exhaust brake is operated by a multi-stage actuator and can be stopped at an intermediate stage, and is configured to be used also as the exhaust throttle valve.

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