JP2018162683A - Reducing agent scattering prevention structure of reducing agent feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reducing agent scattering prevention structure of a reducing agent adding device capable of preventing a problem of corrosion of an exhaust purification device or the like by a scattered reducing agent with a simple configuration. SOLUTION: The reducing agent addition device provided in the exhaust purification device has a reducing agent scattering prevention structure, and the reducing agent addition device 14 accommodates a tip end portion of an injector 16 and is located at a rear end portion of the exhaust gas purification device 50. It has an injector holder 18 attached to the gas collecting chamber 7A and a fixing member 21 that accommodates the rear end portion of the injector 16 and fixes the injector 16 to the injector holder 18, and the fixing member 21 has the injector 16 attached to the fixing member 21. A pipe connecting seat 31 for installing the reducing agent pipe 13 to be connected and a scattering prevention wall 38 that surrounds the outer periphery of the reducing agent pipe 13 connected to the pipe connecting seat 31 and protrudes toward the exhaust purification device 50 are provided. [Selection diagram] Fig. 3

Description

  The present invention relates to a reducing agent scattering prevention structure of a reducing agent addition device.

  2. Description of the Related Art In recent years, a selective reduction catalyst that includes a particulate filter that collects particulates in exhaust gas in the middle of an exhaust pipe, and that can selectively react NOx with ammonia even in the presence of oxygen on the downstream side of the particulate filter. It is proposed that urea water is sprayed as a reducing agent (additive) between the selective catalytic reduction catalyst and the particulate filter to simultaneously reduce particulates and NOx.

  In this case, the urea water is added to the selective catalytic reduction catalyst by an injector (reducing agent adding device) provided between the particulate filter and the selective catalytic reduction catalyst, but the urea water added to the exhaust gas is used. In order to secure a sufficient reaction time for the thermal decomposition into ammonia and carbon dioxide, it is necessary to increase the distance from the urea water addition position to the selective catalytic reduction catalyst. However, in this case, the interval between the particulate filter and the selective catalytic reduction catalyst becomes long, and the mounting property on the vehicle is significantly impaired.

  For this reason, a compact exhaust emission control device 50 as shown in FIGS. 6 and 7 has already been proposed. In the exhaust purification device 50 shown in FIG. 6 and FIG. 7, a particulate filter 3 that traps particulates in the exhaust gas 1 is held in the middle of the exhaust pipe 2 through which the exhaust gas 1 from the engine flows. A first muffler 4 and a second muffler 6 embracing a selective catalytic reduction catalyst 5 which is arranged downstream of the particulate filter 3 and has the property of selectively reacting NOx with ammonia even in the presence of oxygen are arranged in parallel. And an outlet end portion of the particulate filter 3 and an inlet end portion of the selective catalytic reduction catalyst 5 are connected by a communication channel 7 having an S-shaped structure. The exhaust gas 1 discharged from the outlet side end of the particulate filter 3 is folded in the reverse direction and introduced into the inlet side end of the adjacent selective catalytic reduction catalyst 5.

  Here, the communication channel 7 surrounds the outlet side end of the particulate filter 3 and collects the exhaust gas 1 immediately after exiting from the outlet side end while changing the direction in a substantially perpendicular direction. A chamber 7A, a mixing pipe 7B for extracting the exhaust gas 1 collected in the gas collecting chamber 7A in a direction opposite to the exhaust flow of the particulate filter 3, and a direction in which the exhaust gas 1 guided by the mixing pipe 7B is substantially perpendicular The S-shaped structure is formed by the gas dispersion chamber 7C surrounding the inlet side end so that the dispersed exhaust gas 1 can be introduced into the inlet side end of the selective catalytic reduction catalyst 5 while being dispersed. It is configured as follows. In the example of FIG. 6, an oxidation catalyst 8 that oxidizes the exhaust gas 1 is provided in the first stage of the first muffler 4 that holds the particulate filter 3. An ammonia reduction catalyst 9 that oxidizes excess ammonia is provided at the rear stage in the second muffler 6 in which the selective catalytic reduction catalyst 5 is held. In the figure, reference numeral 10 denotes an exhaust port provided downstream of the ammonia reducing catalyst 9.

  The exhaust purification device 50 is mounted on the frame 11 as shown in FIGS. 6 and 7, the second muffler 6 having the exhaust port 10 downstream is located outside the frame 11, and the first muffler is the frame. 11 is fixed to the frame 11 so as to be located inside the frame 11.

  6 and 7, an injector for adding urea water in a direction in which the exhaust gas 1 emitted from the outlet end portion of the particulate filter 3 is changed in a direction substantially perpendicular to the gas collecting chamber 7A. Equipped with 12. That is, the injector 12 is provided on the upper surface farther from the frame 11 at the rear end of the gas collecting chamber 7A so as to inject urea water into the gas collecting chamber 7A toward the frame 11 and obliquely downward. .

  Further, in FIG. 6, the case where the injector 12 is provided on the upper surface far from the frame 11 at the rear end of the gas collecting chamber 7A is shown by a solid line, but instead, as shown by the broken line in FIG. An injector 12 ′ that injects urea water toward the inside of the mixing pipe 7B may be provided on the side near the frame 11 at the rear end of the collecting chamber 7A. In the figure, reference numerals 13 and 13 'denote reducing agent pipes connected to the injectors 12 and 12' to supply a reducing agent to the injectors 12 and 12 '.

  If the above configuration is adopted, particulates in the exhaust gas 1 are collected by the particulate filter 3 and urea water is added to the exhaust gas 1 from the injector 12 or the injector 12 ′, thereby urea. Water is thermally decomposed into ammonia and carbon dioxide, and NOx in the exhaust gas 1 is reduced and purified well by ammonia on the selective catalytic reduction catalyst 5, so that simultaneous reduction of particulates and NOx in the exhaust gas 1 is achieved. Will be.

  At this time, the exhaust gas purification device 50 is configured such that the exhaust gas 1 discharged from the outlet side end portion of the particulate filter 3 is turned back in the reverse direction by the connecting flow path 7 and then the inlet side end of the adjacent selective catalytic reduction catalyst 5. Since the configuration is compactly arranged and the distance from the urea water addition position by the injector 12 to the selective catalytic reduction catalyst 5 is ensured long, the urea water to ammonia can be secured. Sufficient reaction time is ensured to produce.

  Incidentally, as prior art document information related to this type of compact exhaust purification apparatus, there is the following Patent Document 1 and the like.

JP 2015-48715

  As shown in FIGS. 6 and 7, the reducing agent pipes 13 and 13 ′ are connected to the injectors 12 and 12 ′ provided in the exhaust purification device 50, and the reducing agent is connected from the connecting portion of the reducing agent pipes 13 and 13 ′. May leak and scatter. Further, when the reducing agent pipes 13 and 13 ′ are removed from the injectors 12 and 12 ′, or when the reducing agent pipes 13 and 13 ′ are connected to the injectors 12 and 12 ′, the reducing agent is scattered around. Can be considered.

  Since urea water is corrosive to products such as iron, copper, gun metal, and aluminum, when the reducing agent scattered as described above adheres to the surrounding exhaust purification device 50 or the like, the exhaust purification device. There is a problem of corroding 50 grades.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a reducing agent scattering prevention structure for a reducing agent addition device that prevents the problem of corrosion of an exhaust purification device and the like by a scattered reducing agent with a simple configuration. It is said.

The present invention is a reducing agent scattering prevention structure of a reducing agent addition device provided in an exhaust purification device,
The reducing agent adding device accommodates a front end portion of an injector and is attached to a gas collecting chamber located at a rear end portion of the exhaust gas purification device, and a rear end portion of the injector, and the injector is A fixing member for fixing to the injector holder,
The fixing member includes a pipe connection seat for installing a reducing agent pipe to be connected to the injector, and scattering prevention that surrounds the outer periphery of the reducing agent pipe connected to the pipe connection seat and protrudes toward the exhaust purification device side. It is characterized by having a wall.

  Thus, according to the above configuration, the fixing member for holding the injector and fixing it to the injector holder is provided with the pipe connection seat for fixing the reducing agent pipe connected to the injector, and further, the pipe connection seat Because it has a scattering prevention wall that surrounds the outer periphery of the reducing agent pipe connected to the exhaust gas and protrudes toward the exhaust purification device side, even if the reducing agent leaks from the connecting part of the reducing agent pipe, The prevention wall can prevent a problem that the reducing agent is scattered to the exhaust purification device side.

  Further, if the anti-scattering wall is provided with an inclined portion in which the tip of the anti-scattering wall is inclined so as to approach the reducing agent pipe, the reducing agent that collides with the anti-scattering wall is bounced back to prevent scattering. Since it flows down along the wall, the problem of scattering of the reducing agent can be further reduced.

  According to the reducing agent scattering prevention structure of the reducing agent addition apparatus of the present invention described above, various excellent effects as described below can be obtained.

  (I) According to the invention described in claim 1 of the present invention, the fixing member for holding the injector and fixing it to the injector holder is provided with a pipe connection seat for fixing the reducing agent pipe connected to the injector. Furthermore, since the anti-scattering wall is provided around the outer periphery of the reducing agent pipe connected to the pipe connection seat and projecting toward the exhaust gas purification device, the reducing agent leaks from the connecting part of the reducing agent pipe. Further, it is possible to prevent the reducing agent from being scattered to the exhaust purification device side by the scattering prevention wall having a simple configuration. Therefore, it is possible to prevent the problem that the exhaust purification device is oxidized due to adhesion of the reducing agent.

  (II) According to the invention described in claim 2 of the present invention, the anti-scattering wall is provided with the inclined portion in which the tip of the anti-scattering wall is inclined so as to approach the reducing agent pipe. Since the reducing agent that collides with the water flows down along the anti-scattering wall with the inclined portion being turned back, the problem of the reducing agent scattering can be further reduced.

It is a longitudinal cross-sectional view of the fixing member provided with the reducing agent scattering prevention structure which comprises the reducing agent addition apparatus which implements this invention. It is a top view of the fixing member of FIG. It is a side view of a reducing agent addition apparatus. It is an assembly drawing which shows the structure of a reducing agent addition apparatus. It is a top view which shows the example which equipped the exhaust gas purification apparatus with the reducing agent addition apparatus which has a reducing agent scattering prevention structure. It is a top view which shows an example of the exhaust gas purification apparatus which has an injector. FIG. 7 is a side view of the exhaust purification device of FIG. 6.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 4 show an example of an embodiment for carrying out the present invention. In this embodiment, an injector is provided for an exhaust purification device 50 having a configuration substantially similar to that shown in FIGS. 16 is provided with a reducing agent addition device 14 adapted to accommodate 16.

  The reductant addition device 14 shown in FIGS. 1 to 4 is located on the inner side with respect to the frame 11 at the rear end portion (left end portion in FIG. 6) in the gas collecting chamber 7A of the exhaust purification device 50 shown in FIGS. A case where urea water is provided at the position of the upper surface 15 so as to inject into the gas collecting chamber 7A toward the outside of the frame 11 and obliquely downward is shown.

  The reducing agent adding device 14 has an injector holder 18 having a pocket 17 for accommodating the tip 16a of the injector 16 shown in FIG. A water jacket 20 is formed on the outer periphery of the pocket 17 in the injector holder 18 to circulate the cooling water supplied from the cooling water pipe 19 and cool it. The injector holder 18 is fixed to the gas collecting chamber 7A by a bolt 22 (FIG. 3) passed through the bolt hole 22a.

  A fixing member 21 that surrounds the rear end portion 16 b of the injector 16 and is fixed to the injector holder 18 is provided on the upper portion of the injector holder 18. The fixing member 21 is fixed by a fixing bolt 24 that is screwed into a bolt hole 23 provided in the injector holder 18 through a through hole 23 a provided in the fixing member 21. 21a is a leaf spring that urges the injector 16 so that it does not move when the fixing member 21 is fastened and fixed to the injector holder 18 by the fixing bolt 24. In FIG. 3, reference numeral 25 denotes a protective cover which covers the front surface facing the frame 11 of the reducing agent adding device 14 shown in FIG. 6, and the protective cover 25 is formed of the injector holder 18 as shown in FIG. 3 is fixed to a mounting seat 27 provided with a bolt hole 26 via a bolt 28 in FIG.

  1 is a longitudinal sectional view of the fixing member 21, and FIG. 2 is a plan view of FIG. 1. A fitting hole 29 in which the rear end portion 16b of the injector 16 is air-tightly fitted is formed at the lower portion of the fixing member 21. A pipe connection seat 31 having a connection port 30 communicating with the fitting hole 29 is provided at the upper part of the fixing member 21.

  The end of the reducing agent pipe 13 is connected to the connection port 30 of the pipe connection seat 31. Further, a pipe fixing portion 33 having a mounting hole 32 is formed at a position near the pipe connection seat 31 in the fixing member 21, and the reducing agent pipe 13 is fixed to the mounting hole 32 of the pipe fixing portion 33. It is fixed by a bolt 35 through 34. 2, 36 is a mounting hole for mounting a pressure gauge 37 (FIGS. 3 and 4) for detecting the pressure of the reducing agent at the connection port 30.

  1 and 2, the fixing member 21 scatters so as to surround the outer periphery of the reducing agent pipe 13 connected to the connection port 30 of the pipe connection seat 31 so as to protrude toward the exhaust purification device 50. A reducing agent scattering prevention structure 39 including a prevention wall 38 is provided. The scattering prevention wall 38 is provided with a required angle α that can cover the gas collecting chamber 7A side of the exhaust purification device 50 around the center of the connection port 30 to which the reducing agent pipe 13 is connected. In the example of FIG. 1, the scattering prevention wall 38 capable of covering a range of 150 ° is shown. However, for example, the scattering prevention wall 38 capable of covering a range of 90 ° to 180 ° may be used as necessary.

  Further, as shown in FIG. 2, the scattering prevention wall 38 is provided with an inclined portion 38 a that is inclined at a predetermined angle β so as to approach the reducing agent pipe 13 at the tip (upper end) of the scattering prevention wall 38. it can.

  FIG. 5 shows that the reducing agent addition device 14 having the reducing agent scattering prevention structure 39 is positioned on the upper surface 15 on the inner side with respect to the frame 11 at the rear end portion (left end portion in FIG. 6) in the gas collecting chamber 7A of the exhaust purification device 50. It is a top view which shows the example provided, and according to this reducing agent scattering prevention structure 39, also when a reducing agent leaks from the reducing agent piping 13 attached to the piping connection seat 31 of FIG. It is possible to prevent the problem that the reducing agent scatters toward the front side.

  Note that the selective catalytic reduction catalyst 5 shown in FIG. 6 has a property capable of selectively reacting NOx with HC gas even in the presence of oxygen. Therefore, the reducing agent sprayed by the reducing agent adding device 14 is not reduced. In the case of a fuel, the conversion of the fuel into HC gas is promoted. Therefore, fuel can be used as the reducing agent in addition to urea water.

  The reducing agent addition device 14 can also be applied to an exhaust purification device having a structure other than the exhaust purification device 50 shown in FIGS.

  1 to 4, the reducing agent pipe 13 is connected to the injector 16 via the connection port 30 on the fixing member 21 for holding the injector 16 and fixing the injector 16 to the injector holder 18. A pipe connection seat 31 for connection is provided. Further, a scattering prevention wall 38 that surrounds the outer periphery of the reducing agent pipe 13 connected to the pipe connection seat 31 and protrudes toward the gas collecting chamber 7A of the exhaust gas purification device 50 is provided. Since it is provided, even when the reducing agent leaks from the connecting portion of the reducing agent pipe 13, it is possible to prevent the reducing agent from scattering toward the exhaust purification device 50 by the scattering prevention wall 38 having a simple configuration. Therefore, the problem that the exhaust purification device 50 is oxidized by the attachment of the reducing agent can be prevented in advance. Here, since the anti-scattering wall 38 is provided integrally with the fixing member 21 of the reducing agent adding device 14 configured in a compact manner, the anti-scattering wall 38 can be reduced in size, and space saving can be achieved. Further, the anti-scattering wall 38 provided integrally with the fixing member 21 can enhance the durability.

  In addition, since the scattering prevention wall 38 is provided with the inclined portion 38a that is inclined so that the tip of the scattering prevention wall 38 approaches the reducing agent pipe 13, the reducing agent that collides with the scattering prevention wall 38 has the inclined portion 38a. Since it flows back along the anti-scattering wall 38, the reducing agent directed to the anti-scattering wall 38 is reliably removed by the anti-scattering wall 38, and the problem of the reducing agent scattering to the exhaust purification device 50 side can be further reduced. .

  In the above embodiment, the reducing agent addition device 14 is provided at the position of the upper surface 15 on the inner side with respect to the frame 11 at the rear end portion (left end portion in FIG. 6) in the gas collecting chamber 7A of the exhaust gas purification device 50 in FIG. As described with respect to the case, as shown by a broken line in FIG. 6, when the reducing agent addition device 14 is disposed at the position of the injector 12 ′ provided on the side near the frame 11 at the rear end of the gas collecting chamber 7 </ b> A. Can be applied similarly.

  In addition, the reducing agent scattering prevention structure of the reducing agent addition apparatus of the present invention is not limited to the above-described embodiment, and the shape of the scattering prevention wall 38 can be arbitrarily changed, and other departures from the gist of the present invention. Of course, various modifications can be made within the range not to be performed.

13 Reducing agent piping 13 'Reducing agent piping 14 Reducing agent adding device 16 Injector 16a Front end portion 16b Rear end portion 18 Injector holder 21 Fixing member 30 Connection port 31 Piping connection seat 38 Anti-scattering wall 38a Inclined portion 39 Reducing agent scattering prevention structure 50 Exhaust purification device

Claims (2)

A reducing agent scattering prevention structure for a reducing agent addition device provided in an exhaust purification device,
The reducing agent adding device accommodates a front end portion of an injector and is attached to a gas collecting chamber located at a rear end portion of the exhaust gas purification device, and a rear end portion of the injector, and the injector is A fixing member for fixing to the injector holder,
The fixing member includes a pipe connection seat having a connection port for arranging a reducing agent pipe connected to the injector, and an outer periphery of the reducing agent pipe connected to the pipe connection seat so as to surround the exhaust purification device. A reducing agent scattering prevention structure for a reducing agent addition apparatus, comprising a scattering prevention wall protruding toward the bottom.   The reducing agent scattering preventing structure of the reducing agent adding apparatus according to claim 1, wherein the scattering preventing wall has an inclined portion inclined so that a tip approaches the reducing agent pipe.

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