JP2011064137A - Exhaust emission treatment device for diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission treatment device for a diesel engine having high exhaust gas sealing performances of a case connection part and high durability of the case connection part. <P>SOLUTION: In this exhaust emission treatment device for the diesel engine, a DOC 1 is held in a DOC case 2, a DPF 3 is held in a DPF case 4, and a DOC case outlet side end part 6 and a DPF case inlet side end part7 are detachably connected. In the exhaust emission control device, a diameter of the DOC case outlet side end part 6 is set larger than a diameter of the DPF case inlet end part 7, the DOC case outlet side end part 6 is internally fitted in the DPF case inlet end part 7, the adjacent DOC case outlet end part 6 and DOC case middle side part 6a are formed in a same diameter without steps, and the adjacent DPF case inlet end part 7 and DPF case middle side part 7a are formed in a same diameter without steps. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an exhaust treatment device for a diesel engine, and more particularly, to an exhaust treatment device for a diesel engine having high exhaust gas sealing performance at a case connection portion and high durability at a case connection portion.
In this specification and claims, DOC means a diesel oxidation catalyst, DPF means a diesel particulate filter, and PM means particulate matter in exhaust gas.

  Conventionally, as an exhaust treatment device of a diesel engine, there is one in which DOC is accommodated in a DOC case, DPF is accommodated in a DPF case, and a DOC case outlet side end portion and a DPF case inlet side end portion are detachably connected ( (Refer FIG. 1, FIG. 2 of patent document 1).

  According to this type of exhaust treatment device, when PM is captured by the DPF and PM accumulates to some extent, fuel is mixed into the exhaust by post injection into the combustion chamber, fuel injection into the exhaust pipe, etc. By oxidizing and burning, there is an advantage that the temperature of the exhaust can be raised and PM can be incinerated and removed by the heat of the exhaust to regenerate the DPF.

In the thing of FIG. 2 of this patent document 1, the end part on the DOC case outlet side and the end part on the DPF case inlet side have the same diameter and are abutted.
Moreover, in the thing of FIG. 1 of patent document 1, the diameter part of the DOC case exit side end is expanded from the DOC case middle side part adjacent to this DOC case exit side end part by the pipe expansion process.
For this reason, each of the conventional techniques has problems.

JP 2004-263593 A (see FIGS. 1 and 2)

<Problem> The sealing performance of the exhaust gas at the case connecting portion is low.
In the thing of FIG. 2 of patent document 1, since the DOC case exit side edge part and the DPF case entrance side edge part are butt-shaped with the same diameter, compared with what these have fitted, a case connection part The exhaust gas sealing performance is low.

<Problem> The durability of the case connection is low.
In the thing of FIG. 1 of patent document 1, since the diameter of the DOC case exit side end portion is expanded from the DOC case exit side end portion adjacent to the DOC case exit side end portion by the tube expansion processing, the DOC case is subjected to the tube expansion processing. Residual strain remains at the time of diameter expansion, and the durability of the case connecting portion is low.

  An object of the present invention is to provide an exhaust treatment device for a diesel engine, in which the exhaust gas sealing property of the case connecting portion is high and the durability of the case connecting portion is high.

(Invention-specific matters of the invention of claim 1)
As illustrated in FIGS. 1 and 2, the DOC case (2) accommodates the DOC (1), the DPF case (4) accommodates the DPF (3), the DOC case outlet side end (6), and the DPF. In the exhaust treatment device for a diesel engine, which is detachably connected to the case entrance end (7),
The diameter of the DPF case inlet side end (7) is made larger than the diameter of the DOC case outlet side end (6), and the DOC case outlet side end (6) is fitted inside the DPF case inlet side end (7). Let
The adjacent DOC case outlet side end portion (6) and the DOC case middle side portion (6a) are formed with the same diameter and without a step,
An exhaust treatment apparatus for a diesel engine, characterized in that adjacent DPF case inlet side end portions (7) and DPF case intermediate portion (7a) are formed with the same diameter and no step.

(Invention specific matter of invention of claim 4)
As illustrated in FIGS. 3 and 4, the DOC case (2) accommodates the DOC (1), the DPF case (4) accommodates the DPF (3), the DOC case outlet side end (6), and the DPF. In the exhaust treatment device for a diesel engine, which is detachably connected to the case entrance end (7),
The diameter of the DOC case outlet side end (6) is made larger than the diameter of the DPF case inlet side end (7), and the DPF case inlet side end (7) is fitted into the DOC case outlet side end (6). Let
The adjacent DOC case outlet side end portion (6) and the DOC case middle side portion (6a) are formed with the same diameter and without a step,
An exhaust treatment apparatus for a diesel engine, characterized in that adjacent DPF case inlet side end portions (7) and DPF case intermediate portion (7a) are formed with the same diameter and no step.

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> The sealing property of the exhaust gas in the case connecting portion is high.
As illustrated in FIGS. 1 and 2, the diameter of the DPF case inlet side end (7) is made larger than the diameter of the DOC case outlet side end (6), and the DOC case outlet side end (6) Since the inner end of the case entrance side (7) is fitted, the exhaust gas sealing property of the case connecting portion is high.

<Effect> Durability of the case joint is high.
As illustrated in FIGS. 1 and 2, the adjacent DOC case outlet side end portion (6) and the DOC case intermediate side portion (6a) are formed with the same diameter without a step, and the adjacent DPF case inlet side end portion ( 7) and the DPF case middle part (7a) are formed with the same diameter and no step, so that neither the DOC case nor the DPF case has residual distortion when expanding due to the tube expansion process, and the durability of the case connecting portion is high.

(Invention of Claim 2)
The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1.
<Effect> The overall length of the exhaust treatment apparatus can be shortened.
As illustrated in FIGS. 1 and 2, since the sensor mounting boss (28) is attached to the outer periphery of the DPF case middle portion (7a), the DPF case middle without being restricted by the boundary portion of the step. The sensor attachment boss (28) can be attached to the outer periphery of the offset portion (7a), and the sensor (29) can be sufficiently brought close to the DOC outlet side end (12).
Moreover, since the sensor attachment boss (28) is attached to the outer periphery of the DPF case middle portion (7a), the DPF inlet side end (10) can be sufficiently brought close to the sensor (29).
For this reason, the full length of the exhaust treatment device can be shortened.

(Invention of Claim 3)
The invention according to claim 3 has the following effect in addition to the effect of the invention according to claim 1 or claim 2.
<Effect> The DPF can be quickly regenerated.
As illustrated in FIG. 2, the diameter of the DPF case (4) is larger than the diameter of the DOC case (2), and the heat insulating cushion material is disposed between the peripheral walls of the DPF (3) and the DPF case (4). Since (32) is made thicker than the heat insulating cushioning material (22) disposed between the peripheral walls of the DOC (1) and the DOC case (2), the DPF case (4) extends from the peripheral wall of the DPF (3). The heat radiation to the peripheral wall is suppressed by the thick heat insulating cushioning material (32), the temperature of the peripheral wall of the DPF (3) is increased, and the DPF (3) can be quickly regenerated.

<< Effect >> The thing of the same outer diameter normalized by DOC and DPF can be used.
As illustrated in FIG. 2, the diameter of the DPF case (4) is larger than the diameter of the DOC case (2), and the heat insulating cushion material is disposed between the peripheral walls of the DPF (3) and the DPF case (4). (32) is thicker than the insulating cushion material (22) placed between the peripheral walls of DOC (1) and DOC case (2), so it is standardized to DOC (1) and DPF (3) Those having the same outer diameter can be used.

(Invention of Claim 4)
The invention according to claim 4 has the following effects.
<Effect> The sealing property of the exhaust gas in the case connecting portion is high.
As illustrated in FIGS. 3 and 4, the diameter of the DOC case outlet side end (6) is made larger than the diameter of the DPF case inlet side end (7), and the DPF case inlet side end (7) Since the case exit side end (6) is fitted inside, the exhaust gas sealing property of the case connecting portion is high.

<Effect> Durability of the case joint is high.
As shown in FIGS. 3 and 4, the adjacent DOC case outlet side end portion (6) and the DOC case intermediate side portion (6a) are formed with the same diameter without a step, and the adjacent DPF case inlet side end portion ( 7) and the DPF case middle part (7a) are formed with the same diameter and no step, so that neither the DOC case nor the DPF case has residual distortion when expanding due to the tube expansion process, and the durability of the case connecting portion is high.

(Invention according to claim 5)
The invention according to claim 5 has the following effect in addition to the effect of the invention according to claim 4.
<Effect> The overall length of the exhaust treatment apparatus can be shortened.
As illustrated in FIGS. 3 and 4, since the sensor mounting boss (28) for mounting the sensor (29) is mounted on the outer periphery of the DOC case intermediate portion (6 a), the mounting at the boundary portion of the step is limited. Therefore, the sensor attachment boss (28) can be attached to the outer periphery of the DOC case middle portion (6a), and the sensor (29) can be sufficiently brought close to the DOC outlet side end (12).
Further, since the DPF case inlet side end portion (7) is fitted into the DOC case outlet side end portion (6), the DPF inlet side end portion (10) can be sufficiently brought close to the sensor (29).
For this reason, the full length of the exhaust treatment device can be shortened.

(Invention of Claim 6)
The invention according to claim 6 has the following effect in addition to the effect of the invention according to claim 4 or claim 5.
<Effect> The DPF can be quickly regenerated.
As illustrated in FIG. 4, the diameter of the DOC case (2) is larger than the diameter of the DPF case (4), and the heat insulating cushioning material is disposed between the peripheral walls of the DOC (1) and the DOC case (2). Since (22) is made thicker than the heat-insulating cushion material (32) disposed between the peripheral walls of the DPF (3) and the DPF case (4), the DOC case (2) is removed from the peripheral wall of the DOC (1). Heat dissipation to the peripheral wall is suppressed by the thick heat insulating cushioning material (22), the temperature of the peripheral wall of the DOC (1) is increased, the activation of the DOC (1) is promoted, and the regeneration of the DPF (3) is promptly performed Can be done.

1 is a longitudinal side view of an exhaust treatment device device for a diesel engine according to a first embodiment of the present invention. It is an enlarged view of the left side case connection part of the apparatus of FIG. It is a vertical side view of the exhaust-gas treatment apparatus apparatus of the diesel engine which concerns on 2nd Embodiment of this invention. It is an enlarged view of the left side case connection part of the apparatus of FIG.

An exhaust treatment apparatus for a diesel engine according to the first embodiment shown in FIGS. 1 and 2 will be described.
As shown in FIG. 1, DOC (1) is accommodated in DOC case (2), DPF (3) is accommodated in DPF case (4), DOC case outlet side end (6) and DPF case inlet side end The part (7) is detachably connected via a DOC case flange (21) and a DPF case flange (30).

  As shown in FIG. 2, the diameter of the DPF case inlet side end (7) is made larger than the diameter of the DOC case outlet side end (6), and the DOC case outlet side end (6) is connected to the DPF case inlet side end. Next, the adjacent DOC case outlet side end (6) and the DOC case intermediate side portion (6a) are formed with the same diameter without a step, and the adjacent DPF case inlet side end (7) And the DPF case middle portion (7a) are formed with the same diameter and no step.

As shown in FIG. 2, when providing the sensor mounting boss (28) for mounting the sensor (29) disposed between the DOC outlet side end (12) and the DPF inlet side end (10), A sensor mounting boss (28) is mounted on the outer periphery of the portion (7a).
The diameter of the DPF case (4) is made larger than the diameter of the DOC case (2), and the heat insulating cushioning material (32) disposed between the peripheral walls of the DPF (3) and the DPF case (4) is attached to the DOC (1 ) And the DOC case (2) are made thicker than the heat-insulating cushion material (22) disposed between the peripheral walls.
Glass wool is used for the heat-insulating cushion material (32) and the heat-insulating cushion material (22). DOC (1) and DPF (3) are those having the same standardized outer diameter.
The sensor mounting boss (28) is a boss for mounting the DPF inlet side exhaust temperature sensor (29), and the exhaust gas transfer space (14) between the DOC outlet side end (12) and the DPF inlet side end (10). Further, a temperature sensing part (29a) of the DPF inlet side exhaust temperature sensor (29) is inserted.

  As shown in FIG. 1, the DPF case outlet side end portion (8) and the exhaust outlet case inlet side end portion (9) are detachable via the DPF case flange (31) and the exhaust outlet case flange (36). It is connected.

As shown in FIG. 1, the DOC (1) is a ceramic honeycomb carrier that carries an oxidation catalyst and has a flow-through structure in which both ends of the cell (1a) are opened, and the exhaust passes through the inside of the cell (1a). It is like that. The DOC case (2) is composed of a bowl-shaped metal case (18), and a metal cover (19) is overlapped on the outside, and a heat insulating material (20) is filled between them, and the DOC case outlet is opened. The DOC case flange (6a) is placed on the outer periphery of the DOC case intermediate portion (6a) on the boundary side between the DOC case outlet side end portion (6) and the DOC case intermediate portion (6a). 21) is attached, and a heat insulating cushion material (22) is disposed between the peripheral walls of the DOC (1) and the DOC case (2). Glass wool is used for both the heat insulating material (20) and the heat insulating cushioning material (22).
The exhaust inlet pipe (25) is penetrated radially in front of the DOC case (2), and a number of exhaust holes (26) are opened in the peripheral wall of the exhaust inlet pipe (25). The exhaust inlet pipe (25) may not be penetrated for reasons such as securing the strength of the DOC case (2).

  As shown in FIG. 1, DPF (3) is a wall flow monolith in which adjacent cells (3a) are alternately plugged in a ceramic honeycomb carrier. The exhaust gas passes through the inside of the cell (3a) and the wall (3b) of the cell (3a), and captures PM by the wall (3b) of the cell (3a). The DPF case (4) is a cylindrical metal case. A DPF case flange (30) is attached to the outer periphery of the DPF case inlet side end (7), and the DPF case flange is attached to the outer periphery of the DPF case outlet side end (8). (31) is attached. A heat insulating cushion material (32) is disposed between the peripheral walls of the DPF (3) and the DPF case (4). Glass wool is used for the heat insulating cushioning material (32).

The exhaust outlet case (5) is composed of a bowl-shaped metal case (33), and a metal cover (34) is overlapped on the outside thereof, and a heat insulating material (35) is filled therebetween, and the exhaust outlet is opened. An exhaust outlet case flange (36) is provided around the exhaust outlet case inlet end (9) with the case inlet end (9) facing forward. Glass wool is used for the heat insulating material (35). In the exhaust outlet case (5), the exhaust outlet pipe (37) is penetrated in the radial direction, and a number of exhaust holes (38) are opened in the peripheral wall of the exhaust outlet pipe (37). The exhaust outlet pipe (37) may not be penetrated for reasons such as securing the strength of the exhaust outlet case (5).
The DOC case (2), the DPF case (4), and the exhaust outlet case (5) are formed in a bowl shape or a cylinder shape with a circular cross section. It may be formed into a shape.

By overlapping the DOC case flange (21) and the DPF case flange (30) and connecting them with bolts and nuts, the DPF case inlet side end (7) can be freely detached from the DOC case outlet side end (6). Connected to. The nut (42) of the bolt and nut is arranged on the DOC case (2) side, and the bolt (43) is arranged on the DPF case (4) side. A gasket (46) is sandwiched between the DOC case flange (21) and the DPF case flange (30).
By overlapping the DPF case flange (31) and the exhaust outlet case flange (36) and connecting them with bolts and nuts, the exhaust outlet case inlet end (9) is connected to the DPF case outlet end (8). Removably connected. The nut (44) of the bolt and nut is arranged on the exhaust outlet case (5) side, and the bolt (45) is arranged on the DPF case (4) side. A gasket (47) is sandwiched between the DPF case flange (31) and the exhaust outlet case flange (36).

  A sensor mounting boss (23) is provided on the peripheral wall of the DOC case (2) upstream of the DOC (1), and a DOC upstream side exhaust temperature sensor (24) is mounted on the sensor mounting boss (23). A sensor mounting boss (28) is mounted on the outer periphery of the DPF case middle portion (7a) between the DOC outlet side end (12) and the DPF inlet side end (10). A DPF inlet side exhaust temperature sensor (29) is attached. A sensor mounting boss (40) is provided on the peripheral wall of the exhaust outlet case (5) between the DPF (3) and the exhaust outlet pipe (37), and the DPF outlet side exhaust temperature sensor (41) is provided on the sensor mounting boss (40). Is attached. Between the DOC outlet side end portion (12) and the DPF inlet side end portion (10), a DPF inlet side pipe mounting boss (48) is provided on the peripheral wall of the DPF case middle portion (7a), and this DPF inlet side pipe A DPF inlet side exhaust pressure introduction pipe (49) is attached to the attachment boss (48). Between the DPF (3) and the exhaust outlet pipe (37), a DPF outlet side pipe mounting boss (50) is provided on the peripheral wall of the exhaust outlet case (5), and the DPF outlet side pipe mounting boss (50) is connected to the DPF outlet side. An exhaust pressure introduction pipe (51) is attached. The DPF inlet side exhaust pressure introduction pipe (49) and the DPF outlet side exhaust pressure introduction pipe (51) are connected to a differential pressure sensor (52).

DOC upstream side exhaust temperature sensor (24), DPF inlet side exhaust temperature sensor (29), DPF outlet side exhaust temperature sensor (41), differential pressure sensor (52), engine target speed detection sensor (not shown), engine actual A rotation speed detection sensor (not shown) is connected to the engine ECU (not shown), and an electromagnetic valve (not shown) of the injector of the common rail (not shown) is connected to the engine ECU. Based on the exhaust temperature detected by the DOC upstream exhaust temperature sensor (24), the differential pressure upstream and downstream of the DPF (3) by the differential pressure sensor (24), etc., the PM accumulation amount in the DPF (3) is estimated. When the estimated accumulation amount of PM reaches a predetermined regeneration required amount, the regeneration process of the DPF (3) is performed based on the command of the engine ECU.

The regeneration process of DPF (3) is as follows.
When the exhaust temperature detected by the DOC upstream side exhaust temperature sensor (24) does not reach the predetermined DOC activation temperature, after injection is performed, and the exhaust temperature is raised to the DOC activation temperature. When the exhaust temperature exceeds the DOC activation temperature, post-injection is performed, fuel is mixed into the exhaust, and this fuel is oxidized and burned by DOC (1), thereby increasing the temperature of the exhaust, and the heat of the exhaust causes PM to Is removed by incineration to regenerate the DPF (3). In this case, the post injection amount is adjusted according to the exhaust temperature detected by the DPF inlet side exhaust temperature sensor (29). When the exhaust temperature detected by the DPF outlet side exhaust temperature sensor (41) reaches a predetermined abnormality detection temperature, the post injection is stopped or greatly reduced.

The second embodiment shown in FIGS. 3 and 4 differs from the first embodiment shown in FIGS. 1 and 2 in the following points.
As shown in FIG. 4, the diameter of the DOC case outlet side end (6) is made larger than the diameter of the DPF case inlet side end (7), and the DPF case inlet side end (7) is connected to the DOC case outlet side end. It is fitted in the part (6).

  As shown in FIG. 4, when providing the sensor mounting boss (28) for mounting the sensor (29) disposed between the DOC outlet side end (12) and the DPF inlet side end (10), A sensor mounting boss (28) is mounted on the outer periphery of the portion (6a).

As shown in FIG. 4, the diameter of the DOC case (2) is made larger than the diameter of the DPF case (4), and the heat insulating cushion material disposed between the peripheral walls of the DOC (1) and the DOC case (2) ( 22) is made thicker than the heat insulating cushion material (32) disposed between the peripheral walls of the DPF (3) and the DPF case (4).
Other configurations are the same as those in the first embodiment, and the same reference numerals as those in FIGS. 1 and 2 are given to the same elements as those in the first embodiment.

(1) DOC
(2) DOC case
(3) DPF
(4) DPF case
(6) DOC case outlet side end
(6a) Middle part of DOC case
(7) DPF case inlet side end
(7a) Middle part of DPF case
(10) DPF inlet side end
(22) Insulating cushion material
(28) Sensor mounting boss
(29) DPF inlet side exhaust temperature sensor
(32) Insulating cushion material

Claims (6)

DOC (1) is stored in the DOC case (2), DPF (3) is stored in the DPF case (4), and the DOC case outlet side end (6) and the DPF case inlet side end (7) are separated. In an exhaust treatment system for diesel engines that are freely connected,
The diameter of the DPF case inlet side end (7) is made larger than the diameter of the DOC case outlet side end (6), and the DOC case outlet side end (6) is fitted inside the DPF case inlet side end (7). Let
The adjacent DOC case outlet side end portion (6) and the DOC case middle side portion (6a) are formed with the same diameter and without a step,
An exhaust treatment apparatus for a diesel engine, characterized in that adjacent DPF case inlet side end portions (7) and DPF case intermediate portion (7a) are formed with the same diameter and no step. In the exhaust treatment device of the diesel engine according to claim 1,
In providing the sensor mounting boss (28) for mounting the sensor (29) disposed between the DOC outlet side end (12) and the DPF inlet side end (10),
An exhaust treatment device for a diesel engine, characterized in that a sensor mounting boss (28) is attached to the outer periphery of the DPF case middle portion (7a). In the exhaust treatment device for a diesel engine according to claim 1 or 2,
The diameter of the DPF case (4) is larger than the diameter of the DOC case (2),
Thermal insulating cushion material (32) disposed between the peripheral walls of the DPF (3) and the DPF case (4) is disposed between the peripheral walls of the DOC (1) and the DOC case (2) ( An exhaust treatment device for a diesel engine, characterized in that it is thicker than 22). DOC (1) is stored in the DOC case (2), DPF (3) is stored in the DPF case (4), and the DOC case outlet side end (6) and the DPF case inlet side end (7) are separated. In an exhaust treatment system for diesel engines that are freely connected,
The diameter of the DOC case outlet side end (6) is made larger than the diameter of the DPF case inlet side end (7), and the DPF case inlet side end (7) is fitted into the DOC case outlet side end (6). Let
The adjacent DOC case outlet side end portion (6) and the DOC case middle side portion (6a) are formed with the same diameter and without a step,
An exhaust treatment apparatus for a diesel engine, characterized in that adjacent DPF case inlet side end portions (7) and DPF case intermediate portion (7a) are formed with the same diameter and no step. The exhaust gas treatment apparatus for a diesel engine according to claim 4,
In providing the sensor mounting boss (28) for mounting the sensor (29) disposed between the DOC outlet side end (12) and the DPF inlet side end (10),
An exhaust treatment apparatus for a diesel engine, characterized in that a sensor mounting boss (28) is attached to the outer periphery of the intermediate portion (6a) of the DOC case. In the exhaust treatment device for a diesel engine according to claim 4 or 5,
Make the diameter of the DOC case (2) larger than the diameter of the DPF case (4),
Thermal insulating cushion material (22) disposed between the peripheral walls of the DOC (1) and the DOC case (2) is disposed between the peripheral walls of the DPF (3) and the DPF case (4) ( 32) An exhaust treatment device for a diesel engine, characterized in that it is thicker than 32).

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