JP2009091983A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of satisfactorily suppressing temperature drop of exhaust. <P>SOLUTION: A front stage oxidation catalyst 36 and a particulate filter 38 which are an exhaust emission control unit for purifying exhaust from an engine 1 are accommodated in an upstream side casing 30 formed in a cylindrical shape by a heat insulating structure made up of an outer shell 30a and an inner shell 30b provided inside the outer shell 30a so as to be spaced apart therefrom. An exhaust inflow member 52 which is connected to an exhaust pipe 20 keeping exhaust flow therein and which forces exhaust to flow in the first casing 46 is provided to an end 46a of a first casing 46 constituting the upstream side casing 30. The exhaust pipe 20 and exhaust inflow member 52 are connected to each other via an exhaust pipe flange 20a of the exhaust pipe 20 and an inflow member flange 52a on the exhaust inflow member 52. A first cover 68 for covering a region from those exhaust pipe flange 20a and inflow member flange 52a to the end 46a of a first casing 46 being an end of the upstream casing 30 is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification device, and more particularly to an exhaust gas purification device having a casing that employs a heat insulating structure composed of an outer shell and an inner shell.

The engine is provided with an exhaust purification device for preventing atmospheric pollutants such as NOx (nitrogen oxide) and particulates contained in the exhaust from being released into the atmosphere.
For example, for NOx, an ammonia selective reduction type NOx catalyst is disposed in the exhaust passage of the engine, and ammonia is supplied as a reducing agent, so that NOx is selectively reduced by the ammonia selective reduction type NOx catalyst to purify the exhaust gas. An exhaust emission control device is known.

  In addition, for particulates, a conventional technology has been used in which a particulate filter is provided in the exhaust passage of the engine, and the particulates contained in the exhaust are collected by the particulate filter so that the particulates are not released into the atmosphere. It has been. Particulates deposited on this particulate filter are removed from the particulate filter by continuous regeneration using a pre-stage oxidation catalyst and forced regeneration performed as necessary, preventing deterioration of the function of collecting particulates. It has come to be.

  These catalysts used in exhaust emission control devices exhibit a catalytic function by being maintained at a temperature higher than the activation temperature, and the particulate filter is also maintained at a temperature at which deposited particulates are properly removed by incineration. Therefore, various measures are taken so that the temperature of the exhaust gas flowing into the exhaust gas purification device does not decrease and the amount of heat released from the exhaust gas purification device does not increase.

One effective method for preventing a decrease in exhaust temperature is heat insulation of the exhaust pipe, and an inner pipe in which the exhaust flows inside and an outer pipe that is polymerized with a space outside the inner pipe, An exhaust device in which the exhaust pipe has a double pipe structure has been developed and proposed. Similarly, the casing of the exhaust gas purification apparatus is doubled by the outer shell and the inner shell provided inside the outer shell so as to be separated from the outer shell, and a heat insulating effect is obtained by interposing a heat insulating material therebetween. For example, Japanese Patent Application Laid-Open No. H10-228667 proposes the above.
JP 2003-172120 A

By the way, since the casing of the exhaust gas purification device connected to the exhaust pipe of the engine has a diameter larger than the diameter of the exhaust pipe, an exhaust inflow member having a diameter corresponding to the diameter of the exhaust pipe is provided at the end of the casing. In general, the exhaust pipe and the exhaust purification device are connected via the exhaust inflow member.
Since such an exhaust inflow member is formed with a smaller diameter than the casing of the exhaust purification device as described above, it is difficult to form the exhaust inflow member continuously and integrally with the casing. Consists of members. For this reason, in this exhaust inflow member portion, the heat insulating effect as in the casing cannot be obtained, and the temperature of the exhaust gas flowing into the exhaust purification device via the exhaust inflow member is lowered by the heat radiation from the exhaust inflow member. Problems arise.

In addition, the exhaust pipe and the exhaust inflow member are connected through flanges provided on the respective exhaust pipes. Since these flanges serve as heat radiators, the exhaust gas flowing into the exhaust purification device through the exhaust inflow member is connected. The temperature will drop further.
As described above, when the temperature of the exhaust gas flowing into the exhaust purification device decreases due to the heat radiation from the exhaust inflow member or the flange, the function of the catalyst accommodated in the exhaust purification device decreases, and the exhaust purification efficiency is reduced. Problem arises. In addition, the temperature of the particulate filter is lowered, the regeneration of the particulate filter is not performed well, and the amount of particulates deposited on the particulate filter increases. As a result, there also arises a problem that the function of exhaust purification is deteriorated for the particulate filter.

  This invention is made | formed in view of such a subject, The place made into the objective is to provide the exhaust gas purification apparatus which can suppress suitably the temperature fall of the inflowing exhaust gas.

  In order to achieve the above object, an exhaust emission control device according to the present invention has a cylindrical shape with a heat insulating structure comprising an outer shell and an inner shell provided inside the outer shell so as to be separated from the outer shell, and purifies engine exhaust. A casing for housing the exhaust purification unit, and an exhaust pipe that is provided at an end of the casing and is connected to an exhaust pipe through which the exhaust flows through an exhaust pipe connection flange, thereby exhausting the exhaust gas in the exhaust pipe into the casing. An exhaust inflow member to be introduced and an exhaust inflow portion cover covering a region from the exhaust pipe connecting flange to the end of the casing are provided.

  According to the exhaust gas purification apparatus configured as described above, the exhaust gas of the engine flowing in the exhaust pipe flows into the casing via the exhaust inflow member connected to the exhaust pipe, and is stored in the casing. It is purified by. At this time, the region from the exhaust pipe connecting flange to the end of the casing on the exhaust inflow member side is covered with the exhaust inflow portion cover, and heat radiation from the casing is suppressed by the heat insulating structure composed of the outer shell and the inner shell. In addition, the heat exhaust from the exhaust pipe connecting flange and the exhaust inflow member is suppressed by the exhaust inflow portion cover.

Further, in the above exhaust purification apparatus, when the casing is configured by connecting a plurality of divided casing members via the casing connecting flange, a casing part cover that covers the casing connecting flange (Claim 2).
In the exhaust purification device, when the engine and the exhaust purification device are mounted on a vehicle, the traveling wind flows in a direction from the exhaust pipe toward the end of the casing when the vehicle travels. The casing may be disposed in the vehicle.

According to the exhaust emission control device of the present invention, heat radiation from the casing is suppressed by the heat insulating structure composed of the outer shell and the inner shell, and heat radiation from the exhaust pipe connecting flange and the exhaust inflow member is performed by the exhaust inflow portion cover. Therefore, it is possible to satisfactorily suppress the temperature decrease of the exhaust gas flowing into the exhaust gas purification device.
As a result, coupled with the heat dissipation suppression by the casing of the heat insulating structure, it is possible to satisfactorily suppress the temperature decrease in the exhaust purification device and to prevent the function of the exhaust purification unit housed in the exhaust purification device.

  In addition, when the casing of the exhaust purification device is divided into a plurality of casing members, each casing member is connected by a casing connecting flange. Since this casing connecting flange also serves as a heat radiator, the heat insulating effect of the casing is increased. descend. In particular, in order to prevent exhaust from entering between the outer shell and the inner shell of the casing, it is common to reduce the diameter of one of the outer shell and the inner shell so that they are in close contact with each other at the flange portion for casing connection. In this case, since the heat of the exhaust gas is easily transmitted to the outer shell, the amount of heat released from the casing connecting flange increases.

Therefore, according to the exhaust purification device of the second aspect, since the casing coupling flange is covered by the casing portion cover, the heat radiation from the casing coupling flange is suppressed, and the temperature reduction of the exhaust purification device is further suppressed. can do.
According to the exhaust purification device of the third aspect, when the engine and the exhaust purification device are mounted on the vehicle, the traveling wind during traveling of the vehicle is directed from the exhaust pipe toward the end of the casing on the exhaust inflow member side. The casing of the exhaust emission control device is arranged so as to flow, and the region from the exhaust pipe connecting flange to the end of the casing on the exhaust inflow member side is covered with the exhaust inflow portion cover. It is possible to effectively prevent an increase in the amount of heat released by the traveling wind.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram of a four-cylinder vehicle diesel engine (hereinafter referred to as an engine) to which an exhaust emission control device according to an embodiment of the present invention is applied. The exhaust according to the present invention is shown in FIG. The configuration of the purification device will be described.
The engine 1 includes a high-pressure accumulator chamber (hereinafter referred to as a common rail) 2 common to each cylinder, and high-pressure fuel supplied from a fuel injection pump (not shown) and stored in the common rail 2 is supplied to an injector 4 provided in each cylinder. Then, fuel is injected from each injector 4 into each cylinder.

  The intake passage 6 is equipped with a turbocharger 8. The intake air drawn from an air cleaner (not shown) flows into the compressor 8a of the turbocharger 8 from the intake passage 6, and the intake air supercharged by the compressor 8a is intercooler. 10 and the intake control valve 12 are introduced into the intake manifold 14. An intake air amount sensor 16 for detecting an intake air flow rate to the engine 1 is provided upstream of the compressor 8a in the intake passage 6.

On the other hand, an exhaust port (not shown) through which exhaust is discharged from each cylinder of the engine 1 is connected to an exhaust pipe 20 via an exhaust manifold 18. An EGR passage 24 that communicates the exhaust manifold 18 and the intake manifold 14 via the EGR valve 22 is provided between the exhaust manifold 18 and the intake manifold 14.
The exhaust pipe 20 passes through the turbine 8 b of the turbocharger 8 and is connected to an exhaust aftertreatment device 28 via an exhaust throttle valve 26. The rotating shaft of the turbine 8b is connected to the rotating shaft of the compressor 8a so that the turbine 8b receives the exhaust flowing in the exhaust pipe 20 and drives the compressor 8a.

  The exhaust aftertreatment device 28 includes an upstream casing 30 and a downstream casing 34 that is communicated with the downstream side of the upstream casing 30 through a communication passage 32. A pre-stage oxidation catalyst 36 is accommodated in the upstream casing 30, and a particulate filter (hereinafter referred to as a filter) 38 is accommodated on the downstream side of the pre-stage oxidation catalyst 36. In the present embodiment, the upstream casing 30 corresponds to the casing of the present invention, and the upstream oxidation catalyst 36 and the filter 38 constitute the exhaust purification unit of the present invention.

  The filter 38 is provided for collecting particulates in the exhaust gas and purifying the exhaust gas of the engine 1. The filter 38 is made of a honeycomb-type ceramic body, and a large number of passages communicating with the upstream side and the downstream side are arranged side by side, and the upstream side opening and the downstream side opening of the passage are alternately closed. Particulates in the exhaust are collected as the exhaust flows inside.

Since the front-stage oxidation catalyst 36 oxidizes NO in the exhaust gas to generate NO ₂ , by arranging the front-stage oxidation catalyst 36 and the filter 38 in this way, the particulates collected and deposited in the filter 38 are Then, it reacts with NO ₂ supplied from the pre-stage oxidation catalyst 36 and oxidizes, so that the filter 38 is continuously regenerated.
On the other hand, in the downstream casing 34, there is an ammonia selective reduction type NOx catalyst (hereinafter referred to as SCR catalyst) 40 that adsorbs ammonia in the exhaust gas and selectively reduces and purifies NOx in the exhaust gas using the adsorbed ammonia as a reducing agent. In addition to being accommodated, a downstream oxidation catalyst 42 for oxidizing ammonia flowing out from the SCR catalyst 40 to N ₂ is accommodated on the downstream side of the SCR catalyst 40. The post-stage oxidation catalyst 42 also has a function of oxidizing CO generated when the particulates are incinerated by forced regeneration of the filter 38 and discharging it to the atmosphere as CO ₂ .

A urea water injector 44 for injecting and supplying urea water into the exhaust gas flowing out from the filter 38 and flowing into the communication passage 32 is provided on the downstream side of the filter 38 of the upstream casing 30. The urea water is supplied from the tank to the urea water injector 44.
The urea water injected from the urea water injector 44 is hydrolyzed by the heat of the exhaust to become ammonia, and is supplied to the SCR catalyst 40. The SCR catalyst 40 adsorbs the supplied ammonia and promotes a denitration reaction between the adsorbed ammonia and NOx in the exhaust, thereby purifying NOx to be harmless N ₂ . At this time, when ammonia flows out of the SCR catalyst 40 without reacting with NOx, the ammonia is oxidized by the post-stage oxidation catalyst 42 and released into the atmosphere as harmless N _2. Yes.

Next, the configuration of the exhaust casing 28 on the upstream casing 30 side will be described in more detail with reference to FIGS.
FIG. 2 is an external view of the upstream casing 30 in the exhaust aftertreatment device 28, and FIG. 3 is a cross-sectional view of the upstream casing 30 in the axial direction. The exhaust aftertreatment device 28 is used for the engine 1 for a vehicle, and the traveling wind flows from the exhaust pipe 20 to the exhaust aftertreatment device 28, that is, from the left to the right in FIGS. It is arranged so that it is mounted on the vehicle.

  As shown in FIG. 3, the upstream casing 30 includes an outer shell 30a made of a metal plate, an inner shell 30b provided inside the outer shell 30a so as to be separated from the outer shell 30a, and the outer shell 30a and the inner shell 30b. A heat insulating structure composed of a heat insulating material 30c interposed between the first casing 46, the second casing 48, and the third casing 50 is adopted as shown in FIGS. It is divided into three casing members.

  The first casing 46 accommodates the front-stage oxidation catalyst 36 and has an exhaust inflow member 52 that is connected to the exhaust pipe 20 and into which the exhaust of the engine 1 flows. The exhaust inflow member 52 and the exhaust pipe 20 are composed of an inflow member flange (exhaust pipe connection flange) 52 a formed at the end of the exhaust inflow member 52 and an exhaust pipe flange (exhaust gas) formed at the end of the exhaust pipe 20. It is connected via a pipe connecting flange) 20a. The exhaust inflow member 52 extends to the inside of the first casing 46, and a flange-like rectifying plate 52 b is integrally formed at the end in the first casing 46, and the periphery of the rectifying plate 52 b is the periphery of the first casing 46. It is fixed in contact with the inner wall surface. A large number of communication holes are formed in the tubular peripheral wall portion 52c and the flange-shaped rectifying plate 52b of the exhaust inflow member 52 located in the first casing 46 so that exhaust gas flowing in from the exhaust pipe 20 can pass therethrough. It has become.

The diameter of the exhaust inflow member 52 is the same as the diameter of the exhaust pipe 20 for connection with the exhaust pipe 20, and is different from the diameter of the first casing 46. For this reason, the exhaust inflow member 52 is not formed integrally with the first casing 46, and unlike the first casing 46 having the heat insulating structure as described above, the exhaust inflow member 52 is configured based on a single metal tubular member. Yes.
The second casing 48 has a cylindrical shape with both ends opened and accommodates the filter 38. The second casing 48 includes a first flange (casing coupling flange) 54 attached to the downstream end of the first casing 46 and a second flange (casing coupling flange) 56 attached to the upstream end of the second casing 48. Are coupled to the first casing 46. Note that both the attachment portion of the first flange 54 in the first casing 46 and the attachment portion of the second flange 56 in the second casing 48 prevent the intrusion of exhaust gas between the outer shell 30a and the inner shell 30b. Therefore, after the outer shell 30a is reduced in diameter and directly joined to the inner shell 30b, the respective flanges are attached.

  Further, the second casing 48 includes a third flange (casing coupling flange) 58 attached to the downstream end of the second casing 48 and a fourth flange (casing coupling flange) 60 attached to the upstream end of the third casing 50. Are connected to the third casing 50. It should be noted that the attachment portion of the third flange 58 in the second casing 48 and the attachment portion of the fourth flange 60 in the third casing 50 also prevent exhaust from entering between the outer shell 30a and the inner shell 30b. In either case, the outer shell 30a is reduced in diameter and directly joined to the inner shell 30b, and the respective flanges are attached.

The side wall 62 of the third casing 50 is provided with an exhaust outlet 64 through which the exhaust that has passed through the filter 38 flows out toward the communication path 32. As shown in FIGS. 2 and 3, a urea water injector 44 is attached to the side wall portion 62 at a position facing the exhaust outlet 64, and the urea injector 44 directs urea water toward the exhaust outlet 56. Spray.
The end of the exhaust outlet 64 located outside the third casing 50 is connected to the communication path 32, and the end of the exhaust outlet 64 on the side opposite to the communication path 32 is cylindrically shaped. The fluid 66 extends so as to cross the third casing 50 to the side wall portion 62 facing the exhaust outlet 64. On the peripheral surface of the rectifying body 66, a large number of communication holes that communicate the outside and the inside of the rectifying body 66 are formed, and the end of the rectifying body 66 on the side opposite to the communication path 32 is the urea water injector 44. Is fixed to the side wall part 62 so as to surround. Exhaust gas that has passed through the filter 38 flows into the rectifying body 66 through a large number of communication holes formed in the rectifying body 66, then flows into the communication passage 32 through the exhaust outlet 64, and further flows into the downstream casing 34. Flows in.

  The upstream casing 30 is configured as described above, and the first casing 46, the second casing 48, and the third casing 50 are provided with an outer shell 30a and an inner shell 30b, and interposed between the outer shell 30a and the inner shell 30b. By adopting a heat insulating structure composed of the heat insulating material 30c, heat dissipation from the upstream casing 30 is suppressed. However, for those places where such a heat insulating structure is not applied, further heat dissipation suppression measures are taken. ing.

That is, in the region from the inflow member flange 52a and the exhaust pipe flange 20a to the end portion 46a of the first casing 46 that is the end portion of the upstream casing 30 on the exhaust pipe 20 side, the inflow member flange 52a and the exhaust pipe flange A first cover (exhaust inflow portion cover) 68 that covers 20 a, the exhaust inflow member 52, and the end portion 46 a of the first casing 46 is provided.
4 is a cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 3, but is shown in FIG. 1, FIG. 2, FIG. As described above, the first cover 68 has a vertically divided structure including the first upper cover 68a and the first lower cover 68b. And the flange part 68c formed in the side edge part of the 1st upper cover 68a and the flange part 68d formed in the side edge part of the 1st lower cover 68b are connected with a volt | bolt and a nut, and this bolt is tightened. Thus, both axial ends of the first cover 68 are fixed to the peripheral surface of the exhaust pipe 20 and the peripheral surface of the first casing 46, respectively. Note that these both end portions may be in close contact with the peripheral surface of the exhaust pipe 20 and the peripheral surface of the first casing 46 after interposing a cushioning material or a heat insulating material.

  By attaching the first cover 68 in this manner, heat dissipation from the inflow member flange 52a and the exhaust pipe flange 20a serving as a heat radiator and the exhaust inflow member 52 to which the heat insulating structure is not applied is satisfactorily suppressed. Further, as described above, the traveling wind flows in the direction from the exhaust pipe 20 toward the upstream casing 30 during traveling of the vehicle, but the end portion of the upstream casing 30 serving as a front end portion with respect to such traveling wind, That is, the traveling wind does not directly fall on the end 46a of the first casing 46, and cooling by the traveling wind is prevented.

As a result, the temperature drop of the exhaust gas flowing into the upstream casing 30 from the exhaust pipe 20 is well suppressed, and the temperature drop of the upstream casing 30 itself is also well suppressed. It is possible to prevent the exhaust gas purification function from being lowered or the exhaust gas purification function from being lowered due to insufficient regeneration of the filter 38.
In the present embodiment, the first flange 54 and the second flange 56 that connect the first casing 46 and the second casing 48 are also provided with a second cover (casing portion cover) 70 that covers them.

  6 is a cross-sectional view taken along line VI-VI in FIG. 3, and FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 3, but is shown in FIGS. 1, 2, 6, and 7. As described above, the second cover 70 has a vertically divided structure composed of the second upper cover 70a and the second lower cover 70b, similarly to the first cover 68 described above. And the flange part 70c formed in the side edge part of the 2nd upper cover 70a and the flange part 70d formed in the side edge part of the 2nd lower cover 70b are connected with a volt | bolt and a nut, and this bolt is tightened. Thus, both axial ends of the second cover 70 are fixed to the peripheral surface of the first casing 46 and the peripheral surface of the second casing 48, respectively. As in the case of the first cover 68, both end portions of the second cover 70 are in close contact with the peripheral surfaces of the first casing 46 and the second casing 48 with a cushioning material or a sealing material interposed therebetween. Also good.

Further, a third cover (casing portion cover) 72 that covers the third flange 58 and the fourth flange 60 that connect the second casing 48 and the third casing 50 is also provided.
The outer shape of the third cover 72 and the cross-sectional shape in the direction perpendicular to the axis of the upstream casing 30 are substantially the same as those of the second cover 70 described above. As shown in FIGS. The cover 72 has a vertically divided structure composed of a third upper cover 72a and a third lower cover 72b. And the flange part 72c formed in the side edge part of the 3rd upper cover 72a and the flange part 72d formed in the side edge part of the 3rd lower cover 72b are connected with a volt | bolt and a nut, and this bolt is tightened. Thus, both axial ends of the third cover 72 are fixed to the peripheral surface of the second casing 48 and the peripheral surface of the third casing 50, respectively. As in the case of the first cover 68 and the second cover 70, both end portions of the third cover 72 are provided on the peripheral surfaces of the second casing 48 and the third casing 50 with a cushioning material or a sealing material interposed therebetween. You may make it closely_contact | adhere.

  As described above, the flange mounting portion of each casing is directly joined to the inner shell 30b by reducing the diameter of the outer shell 30a in order to prevent exhaust from entering between the outer shell 30a and the inner shell 30b. Therefore, the heat of the exhaust is easily transmitted to each flange without obtaining a heat insulating effect. Therefore, by attaching the second cover 70 to the first flange 54 and the second flange 56 and attaching the third cover 72 to the third flange 58 and the fourth flange 60 in this way, heat is radiated from these flanges serving as heat radiators. Is satisfactorily suppressed.

As a result, in combination with the heat insulating structure of each casing in which the heat insulating material 30c is interposed between the outer shell 30a and the inner shell 30b, the temperature decrease in the upstream casing 30 is well suppressed, and the temperature decreases. Accordingly, it is possible to prevent a decrease in the function of the pre-stage oxidation catalyst 36 and a decrease in the exhaust purification function due to insufficient regeneration of the filter 38.
Further, in addition to the first cover 68 described above, the second cover 70 and the third cover 78 also satisfactorily suppress the temperature drop of the exhaust gas flowing in the upstream casing 30, so that the exhaust gas maintained at a high temperature can be discharged downstream. It becomes possible to supply to the side casing 34, and it is possible to prevent the exhaust purification function of the SCR catalyst 40 and the post-stage oxidation catalyst 42 housed in the downstream casing 34 from being lowered.

Although the description of the exhaust emission control device according to one embodiment of the present invention is finished above, the present invention is not limited to the above embodiment.
That is, in the above embodiment, the first cover 68, the second cover 70, and the third cover 72 provided in the upstream casing 30 are all divided into two in the vertical direction. The mounting structure is not limited to that of the above-described embodiment, and can be variously modified as necessary. For example, these covers may be divided into left and right parts, or divided into three or more parts, or connected with another connecting member such as a clip without being connected with bolts and nuts. Also good.

  Moreover, in the said embodiment, in addition to the 1st cover 68 provided in the area | region from the inflow member flange 52a and the exhaust pipe flange 20a to the edge part 46a of the 1st casing 46 by the side of the exhaust pipe 20, the flange which connects each casing The second cover 70 and the second cover 72 are also provided in this portion so as to suppress the heat radiation from the upstream casing 30 to the maximum, but at least one of the second cover 70 and the third cover 72 is necessary. One may be omitted.

  Furthermore, although the present invention is applied to the upstream casing 30 in the above embodiment, the present invention can also be applied to the downstream casing 34 in the same manner. In the above embodiment, the front-stage oxidation catalyst 36 and the filter 38 correspond to the exhaust purification unit of the present invention. However, the exhaust purification unit housed in the casing is not limited to this, and there are various types. The present invention can be applied to a casing that houses an exhaust purification unit. Therefore, the configuration of the exhaust aftertreatment device used in the above embodiment can be variously modified. For example, the upstream casing 30 and the downstream casing 34 are directly communicated without using the communication passage 32. Further, the exhaust purification mechanism such as a catalyst accommodated in the downstream casing 34 is not limited to the above embodiment.

  In the above embodiment, the engine 1 is a four-cylinder diesel engine. However, the number of cylinders and the type of the engine 1 are not limited thereto, and the engine 1 includes an exhaust purification device in which an exhaust purification unit is housed in a casing. The present invention can be applied if there is any.

1 is an overall configuration diagram of an engine to which an exhaust emission control device according to an embodiment of the present invention is applied. It is an external view of an upstream casing. It is sectional drawing of the axial direction of an upstream casing. It is sectional drawing which follows the IV-IV line in FIG. It is sectional drawing which follows the VV line in FIG. It is sectional drawing which follows the VI-VI line in FIG. It is sectional drawing which follows the VII-VII line in FIG.

Explanation of symbols

1 Engine 20 Exhaust pipe 20a Exhaust pipe flange (flange for exhaust pipe connection)
30 Upstream casing (casing)
30a Outer shell 30b Inner shell 36 Pre-stage oxidation catalyst (exhaust gas purification unit)
38 Particulate filter (exhaust gas purification unit)
46 1st casing (casing member)
46a end 52 exhaust inflow member 52a inflow member flange (exhaust pipe connection flange)
54 1st flange (casing connecting flange)
56 Second flange (casing connection flange)
58 3rd flange (casing connection flange)
60 4th flange (casing connecting flange)
68 First cover (exhaust air inlet cover)
70 Second cover (casing cover)
72 Third cover (casing cover)

Claims (3)

A casing that accommodates an exhaust purification unit that purifies the exhaust of the engine by forming a cylindrical shape with an outer shell and a heat insulating structure made of an inner shell provided inside the outer shell and spaced from the outer shell;
An exhaust inflow member that is provided at an end of the casing and is connected to an exhaust pipe through which the exhaust gas flows through an exhaust pipe connection flange, thereby allowing the exhaust in the exhaust pipe to flow into the casing;
An exhaust purification device comprising: an exhaust inflow cover that covers an area from the exhaust pipe connection flange to the end of the casing. The casing is configured by connecting a plurality of divided casing members via a casing connecting flange,
The exhaust emission control device according to claim 1, further comprising a casing cover that covers the casing coupling flange. The engine and the exhaust emission control device are mounted on a vehicle,
2. The exhaust gas purification according to claim 1, wherein the casing is disposed in the vehicle so that a traveling wind flows in a direction from the exhaust pipe toward the end of the casing when the vehicle travels. apparatus.

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