WO2016013319A1

WO2016013319A1 - Dosing pipe

Info

Publication number: WO2016013319A1
Application number: PCT/JP2015/066884
Authority: WO
Inventors: 好伸永田
Original assignee: フタバ産業株式会社
Priority date: 2014-07-25
Filing date: 2015-06-11
Publication date: 2016-01-28
Also published as: JPWO2016013319A1

Abstract

A dosing pipe provided with: a main body portion forming a tubular injection channel having an opening portion; an inlet opened toward an exhaust upstream side of an exhaust pipe; an ejection port for ejecting an exhaust gas that forms an air curtain directed toward the opening portion in the main body portion; and a flow channel portion that guides the exhaust gas taken through the inlet to the ejection port.

Description

Dosing pipe

Cross-reference of related applications

This international application claims priority based on Japanese Patent Application No. 2014-151896 filed with the Japan Patent Office on July 25, 2014. The entire contents are incorporated herein by reference.

The present invention relates to a dosing pipe used by being attached to an exhaust pipe.

The exhaust pipe is provided with a catalyst for exhaust gas purification. Further, in the exhaust pipe on the upstream side of the exhaust of the catalyst, a reducing agent such as urea water is injected toward the catalyst in order to maintain the performance of the catalyst.
However, an injection such as a reducing agent may adhere to the inner wall surface of the exhaust pipe due to the influence of the exhaust gas (for example, the injection direction is changed by the exhaust gas). In that case, the problem that the deposit which is the lump of the deposit derived from the injection thing or the lump of the chemically reacted injection substance may be formed in the inner wall surface of the exhaust pipe or the like.

In order to solve this problem, the urea water is less affected by the flow of the exhaust gas by taking in air from the intake system and ejecting the taken air from around the injection port of the injected matter. Proposals for suppressing the occurrence have been made (for example, Patent Document 1).

JP 2010-059805 A

However, high-pressure exhaust gas is flowing in the exhaust pipe, and it has been difficult to eject air with a momentum sufficient to resist this.
In Patent Document 1, air is sent from the intake system to the exhaust pipe at the timing when the fuel is injected from the injector, but the timing at which the fuel is injected from the injector is different from the timing at which the exhaust gas flows through the exhaust pipe in the first place. The above problem could not be solved.

In one aspect of the present invention, it is desirable to be able to provide a dosing pipe that enables injection of an injection material in an exhaust pipe while suppressing generation of deposits by the injection material.

The dosing pipe of one aspect of the present invention is
A dosing pipe that is attached to an exhaust pipe and used.
A main body that forms a cylindrical injection passage having an opening that opens inside the exhaust pipe;
An intake opening that opens toward the exhaust upstream side of the exhaust pipe inside the exhaust pipe on the exhaust upstream side of the opening;
When the inside of the injection path is viewed through the opening, an air curtain is provided at a position that surrounds an injection range in which an injection material is injected in a cone shape in the injection path, and surrounds the injection range toward the opening. A spout for ejecting the exhaust gas to be formed;
The flow passage section has a larger flow passage cross-sectional area than the opening area opened toward the opening, and the flow passage section guides the exhaust gas taken in at the intake opening to the jet outlet.
Is provided.

When the dosing pipe is attached to the exhaust pipe and the injection is injected through the injection path formed by the main body, the injection is injected into the exhaust pipe from the opening.
Further, when exhaust gas is caused to flow through the exhaust pipe to which the dosing pipe is attached, the exhaust gas is taken into the flow path portion from the intake port that is opened upstream of the opening portion. And the taken-in exhaust gas forms the air curtain surrounding the injected injection material.

At this time, since the intake port opens toward the upstream side of the exhaust pipe, dynamic pressure acts on the exhaust gas taken in from the intake port. In addition, since the intake port is opened upstream from the opening, a higher dynamic pressure acts on the exhaust gas as compared with the case where the intake is installed near the opening.

In addition, since the opening area of the jet port is smaller than the channel cross-sectional area of the channel part, a high dynamic pressure acts on the exhaust gas when flowing into the channel part.
Therefore, when the dosing pipe is attached to the exhaust pipe, exhaust gas having a higher momentum than the exhaust gas flowing in the vicinity of the opening can be ejected from the ejection port.

Therefore, when the above-described dosing pipe is used, the exhaust gas ejected from the ejection port is prevented from adhering the injection material to the inside of the main body, so that the occurrence of deposits in the dosing pipe can be suppressed.

Further, when the dosing pipe is used, the exhaust gas ejected from the ejection port serves as an air curtain that resists the high-pressure exhaust gas flowing in the exhaust pipe.
For this reason, it is possible to suppress the injection material flowing out from the dosing pipe into the exhaust pipe from being pushed by the exhaust gas flowing through the exhaust pipe and being biased in the pushed direction in the exhaust pipe.

Therefore, when the dosing pipe is attached to the exhaust pipe, the injection can be injected into the exhaust pipe while suppressing the generation of deposits.
In addition, since an injection is injected in an exhaust pipe from an opening part, the bias | inclination is suppressed, When it merges with the exhaust gas which flows through the inside of an exhaust pipe, it will be disperse | distributed to the whole exhaust gas substantially uniformly.

In addition, the opening area in which the jet port is open toward the opening can also be referred to as, for example, the area of the projection surface when the jet port is projected in the direction of viewing the inside of the injection path through the opening. It can also be said to be the area of a cross section perpendicular to the axial direction.

In the dosing pipe, the main body portion may be formed in a double tubular shape having an inner cylindrical portion and an outer cylindrical portion.
In this case, the intake port may be formed in the outer cylindrical portion, and the ejection port may be provided so as to be positioned inside the inner cylindrical portion when the inside of the ejection path is viewed through the opening.

The flow path portion is formed by a space between the inner cylindrical portion and the outer cylindrical portion, and a direction changing portion that changes the direction of the exhaust gas flowing from the intake port in the direction from the jet port toward the opening portion. You may make it prepare.

In this case, since the outer cylindrical part of the main body becomes the outer edge of the dosing pipe, a hole through which the upper part of the outer cylinder passes is formed in the exhaust pipe, and the main body is formed in the hole so that the intake port faces the upstream side of the exhaust pipe. The dosing pipe is attached to the exhaust pipe by being inserted.

If the dosing pipe has an overlap part where the end of the outer cylindrical part opposite to the side where the opening is provided is folded back to the position where it covers the inner side of the inner cylindrical part, the dosing pipe is injected into the overlap part. An outlet may be formed.

If it does in this way, a spout will open on the inner surface of an inner cylindrical part, or a position near the inner surface of an inner cylindrical part, and the position of a spout can be installed in the position near an inner cylindrical part. Therefore, the dosing pipe can be minimized.

By the way, when a flow-path part is formed of the space between an inner side cylindrical part and an outer side cylindrical part, it is good to provide an intake port in the position near the opening part side.
In this way, the amount of exhaust gas directed toward the opening is reduced, so that dispersion of dynamic pressure applied to the exhaust gas can be suppressed.

As a result, the exhaust gas can be ejected vigorously from the ejection port as compared with the case where the intake port is arranged at another location.
Next, in the case of a dosing pipe having a double-pipe main body, the main body is a length along the central axis of the main body, and the center of the main body with respect to the side where the intake port is provided It is good also as a shape where the opening surface of an opening part inclines with respect to the central axis of a main-body part so that the length of the other side on both sides of an axis | shaft may become short compared with the side in which the intake port was provided.

In this way, since the volume of the flow path portion is reduced, it is possible to suppress the dispersion of the dynamic pressure applied to the exhaust gas taken in from the intake port.
Next, the main body portion has a blowing portion provided along the circumferential direction on the inner wall surface on the end portion side opposite to the end portion side where the opening portion is formed, and the blowing portion is provided through the opening portion. When viewed, the pipe portion that has the jet opening that opens toward the opening portion side, extends from the intake port that opens upstream from the opening portion toward the blowing portion, and forms a flow path portion. It is good also as a structure provided.

In this case, the main body portion may be a single tube structure, and it is only necessary to form a blow-in portion in the main body portion of the single tube structure, attach the main body portion to the exhaust pipe, and attach the pipe portion to the exhaust pipe.
Therefore, when the dosing pipe of the present invention is used, a simple structure main body portion is formed without forming a complicated structure main body portion, which is attached to the exhaust pipe, and the pipe portion is simply attached to the exhaust pipe. Good.

The main body portion may be formed in a shape whose diameter increases toward the opening, for example, a trumpet shape.
Moreover, a jet nozzle is good also as a slit-shaped opening formed in the ring shape.

Also, the spout may have a shape in which a plurality of holes are arranged in a circle.

It is explanatory drawing for demonstrating the dosing pipe of 1st Embodiment, and is sectional drawing of the exhaust pipe and dosing pipe of the exhaust gas upstream side of the part by which the catalyst is arrange | positioned. FIG. 2A is a perspective view of the dosing pipe. FIG. 2B is a plan view of FIG. 2A. FIG. 2C is a sectional view of FIG. 2B taken along IIC-IIC. FIG. 2D is a cross-sectional view of FIG. 2C taken along IID-IID. FIG. 3A is a perspective view of a modified example of the dosing pipe. FIG. 3B is a plan view of FIG. 3A. FIG. 3C is a sectional view of FIG. 3B taken along IIIC-IIIC. FIG. 4A is a perspective view of a modified example of the dosing pipe. FIG. 4B is a plan view of FIG. 4A. FIG. 4C is a sectional view of FIG. 4B taken along IVC-IVC. FIG. 5A is a perspective view of a modified example of the dosing pipe. FIG. B is a plan view of FIG. 5A. FIG. 5C is a sectional view taken along the line VC-VC of FIG. 5B. FIG. 5D is a VD-VD cross-sectional view of FIG. 5C. FIG. 6A is a cross-sectional view of the dosing pipe on which FIG. 2C has been reprinted in order to explain the cutting positions of the cutting planes shown in FIG. 6B to FIG. 6D. FIG. 6B is a view showing a modified example of the dosing pipe, and is a cross-sectional view of FIG. 6A along VIB-VIB. FIG. 6C is a view showing a modified example of the dosing pipe, and is a cross-sectional view of FIG. 6A along VIB-VIB. FIG. 6D is a view showing a modified example of the dosing pipe, and is a VIB-VIB sectional view of FIG. 6A. FIG. 7A is an explanatory view of a modified example of the dosing pipe, and is a cross-sectional view cut along the same cut surface as FIG. 2C. FIG. 7B is an explanatory view of a modified example of the dosing pipe, and is a cross-sectional view cut along the same cut surface as FIG. 2C. It is explanatory drawing for demonstrating the dosing pipe of 2nd Embodiment, and is sectional drawing of the exhaust pipe of the exhaust upstream of the part by which the catalyst is arrange | positioned, a dosing pipe, and a pipe part. It is explanatory drawing for demonstrating the modification of the dosing pipe of 2nd Embodiment, and is an exhaust pipe of the exhaust upstream side of the part by which the catalyst is arrange | positioned, the modification of a dosing pipe, and sectional drawing of a pipe part.

DESCRIPTION OF SYMBOLS 1 ... Dosing pipe 10 ... Pipe part 2 ... Main-body part 3 ... Intake port 4 ... Jet port 5 ... Flow path part 9 ... Injection port 20 ... Inner cylindrical part 200 ... Injection path 21 ... Outer cylindrical part 22 ... Opening part 23 ... Back opening 24 ... Overlap part 26 ... Blow-in part 40 ... Plate material 50 ... Direction change part h ... Exhaust pipe

(First embodiment)
A first embodiment to which the present invention is applied will be described below with reference to the drawings.
In addition, the arrow to which the code | symbol 95 was attached | subjected in FIG.1, FIG.8, FIG.9 has shown the flow of exhaust gas.

The two-dot chain lines in FIG. 2A, FIG. 3A, FIG. 4A, and FIG. 5A are lines written to express the shape of the dosing pipe, and are lines attached to the dosing pipe itself. is not.

As shown in FIG. 1, the dosing pipe 1 of the first embodiment is formed in a cylindrical shape, and the exhaust pipe h is bent on the exhaust upstream side of the exhaust pipe h where the catalyst is attached. It is installed in the part.

Specifically, in the bent portion of the exhaust pipe h, a hole is formed in the pipe surface on the side (outside) far from the bending center 92. The dosing pipe 1 is installed in the exhaust pipe h by passing the dosing pipe 1 through the hole.

At this time, the dosing pipe 1 is connected to the exhaust pipe h so that the opening 22 provided at one end of both ends in the axial direction is opposed to the catalyst installed on the exhaust downstream side in the exhaust pipe h. Installed.

The dosing pipe 1 is welded to the exhaust pipe h.
As shown in FIG. 2, the dosing pipe 1 includes a main body portion 2 including an inner cylindrical portion 20 and an outer cylindrical portion 21. The inner cylindrical portion 20 and the outer cylindrical portion 21 are arranged coaxially.

Among these, the inner cylindrical part 20 forms the cylindrical injection path 200 which has the opening part 22 opened inside the exhaust pipe in the inner side.
On the other hand, an intake port 3 for taking in exhaust gas is provided on the cylindrical surface of the outer cylindrical portion 21.

The intake 3 is provided at a position close to the opening 22. Specifically, the intake port 3 is provided at a position closer to the opening 22 side than the center of the main body 2 when viewed in the direction along the central axis 91 of the main body 2.

When the dosing pipe 1 is installed in the exhaust pipe h, the dosing pipe 1 is installed so that the intake port 3 opens toward the exhaust upstream side (see FIG. 1).
The dosing pipe 1 is folded so that one end (the end on the side facing the catalyst when installed in the exhaust pipe h) of both ends in the axial direction of the outer cylindrical portion 21 is drawn in a semicircle, The inner cylindrical portion 20 is connected to one end portion of both end portions in the axial direction. The aforementioned opening 22 is formed inside the folded portion.

On the other hand, the other end portion of the outer cylindrical portion 21 is folded back so as to draw a semicircle with a flat top portion up to a position where an overlap portion 24 is formed covering the other end portion of the inner cylindrical portion 20 from the inside. ing. The rear opening 23 opens inside the folded portion.

The overlap part 24 forms a space between the inner wall surface of the inner cylindrical part 20 as shown in FIG. 2C and FIG. 2D. Then, when it sees through the opening part 22, when it sees through the opening part 22, the slit formed in the ring shape which is the jet nozzle 4 opened toward the opening part 22 side is formed.

In the first embodiment, urea water, which is a reducing agent, is injected as a spray in the shape of a cone in the injection path 200, but the overlap part 24 is configured in this way, and thus the injection path through the opening 22. When the inside of the nozzle 200 is viewed, the outlet 4 is provided at a position surrounding the injection range 90 in which the urea water is injected in a cone shape in the injection path 200.

Therefore, when the exhaust gas taken in from the intake port 3 is ejected from the jet port 4 formed in this way, an air curtain is formed that surrounds the urea water injection range 90 and faces the opening 22.

Next, in the dosing pipe 1 of the first embodiment, the flow path portion 5 that guides the exhaust gas taken in at the intake port 3 to the jet port 4 is formed between the inner cylindrical portion 20 and the outer cylindrical portion 21. Is done.
The flow path portion 5 has an area shown in FIG. 2D and has a larger flow path cross-sectional area than the opening area where the jet nozzle 4 opens toward the opening portion 22.

In the flow path part 5, the other end part side (the direction side in which the rear opening part 23 opens) as viewed from the overlap part 24 is taken in by folding the other end part side of the outer cylindrical part 21. A direction changing portion 50 is formed that turns back the direction in which the exhaust gas taken in at the port 3 flows from the outlet 4 toward the opening 22.

As shown in FIG. 1, an injector (not shown) is installed on the dosing pipe 1 configured in this manner so that the injection port 9 is located at the center of the rear opening 23. In the injector of the first embodiment, urea water is injected.

The injection direction of urea water in the first embodiment is a direction in which the injection axis coincides with the central axis 91 of the main body 2 and is directed from the rear opening 23 toward the opening 22.
(Characteristic effects of the first embodiment)
When the dosing pipe 1 described above is attached to the exhaust pipe h on the exhaust upstream side of the catalyst and urea water is injected through the injection path 200 formed by the main body 2, the urea water is introduced into the exhaust pipe h from the opening 22. leak.

Further, when the exhaust gas is caused to flow through the exhaust pipe h to which the dosing pipe 1 is attached, the exhaust gas is taken into the flow path portion 5 from the intake port 3 that is open upstream of the opening portion 22. . The taken-in exhaust gas forms an air curtain surrounding the injected urea water.

At this time, since the intake port 3 opens toward the upstream side of the exhaust pipe h, dynamic pressure acts on the exhaust gas taken in from the intake port 3. In addition, since the intake port 3 is opened upstream of the opening 22, a higher dynamic pressure acts on the exhaust gas than when the intake 3 is installed in the opening 22.

Also, the opening area of the jet port 4 is smaller than the cross-sectional area of the flow path portion 5. Therefore, the exhaust gas is ejected vigorously from the ejection port 4 by the exhaust gas on which the high dynamic pressure that flows into the flow path portion 5 acts.

Therefore, when the dosing pipe 1 of the first embodiment is attached to the exhaust pipe h, exhaust gas having a stronger momentum than the exhaust gas flowing in the vicinity of the opening 22 can be ejected from the ejection port 4.

Therefore, when the dosing pipe 1 of the first embodiment is used, the exhaust gas ejected from the ejection port 4 suppresses the adhesion of urea water inside the main body 2, so that the generation of deposits in the dosing pipe 1 is prevented. Can be suppressed.

Further, when the dosing pipe 1 of the first embodiment is used, the exhaust gas ejected from the ejection port 4 serves as an air curtain that resists the high-pressure exhaust gas flowing through the exhaust pipe h.
Therefore, urea water flowing out from the dosing pipe 1 into the exhaust pipe h is pushed by the exhaust gas flowing through the exhaust pipe h, and is prevented from being biased in the pushed direction in the exhaust pipe h.

Therefore, when the dosing pipe 1 is attached to the exhaust pipe h, urea water can be injected into the exhaust pipe h while suppressing generation of deposits due to urea water.
The urea water is injected into the exhaust pipe h from the opening 22 in a state in which the bias is suppressed. Therefore, when the urea water merges with the exhaust gas flowing through the exhaust pipe h, the urea water is almost uniformly dispersed throughout the exhaust gas. The

Further, in the first embodiment, by forming the overlap portion 24, the jet nozzle 4 opens on the inner surface of the inner cylindrical portion 20 or at a position close to the inner surface of the inner cylindrical portion 20. Since the position of the spout 4 can be installed at a position close to the inner cylindrical portion 20, the dosing pipe 1 can be minimized.

Next, in the dosing pipe 1 of the first embodiment, since the outer cylindrical portion 21 of the main body portion 2 becomes the outer edge of the dosing pipe 1, a hole through which the outer cylindrical portion 21 passes is formed in the exhaust pipe h, and the intake port The main body 2 can be attached to the exhaust pipe h simply by inserting the main body 2 into the hole so that 3 faces the upstream side of the exhaust pipe h.

In addition, the intake port 3 of the dosing pipe 1 of the first embodiment is provided at a position closer to the opening 22 side than the center of the main body 2 when viewed in the direction along the central axis 91. In the space formed between the outer cylindrical portion 21 and the inner cylindrical portion 20, the amount of exhaust gas directed to the side opposite to the ejection port 4 when viewed from the intake port 3 is reduced. Therefore, dispersion of dynamic pressure applied to the exhaust gas taken in from the intake port 3 can be reduced. And as a result, compared with the case where the intake 3 is arrange | positioned in another place, exhaust gas can be spouted from the jet outlet 4 vigorously.

By the way, the following example is given as a modification of the dosing pipe 1.
(1) First, as shown in FIG. 3A to FIG. 3C, the diameter of the dosing pipe 1 increases from the other end side toward one end side, that is, the opening 22 side. You may form so that it may become a shape, what is called a trumpet shape.

If it does in this way, even if the distance from the injection port 9 (refer FIG. 1) to the opening part 22 is short, urea water can be injected in a wide range.
(2) Secondly, as shown in FIG. 4A to FIG. 4C, the main body 2 has a longer length along the central axis 91 than the side where the intake 3 is provided. You may make it the opening surface of the opening part 22 incline with respect to the center axis | shaft 91 so that the opposite side on both sides may become short.

In this way, since the volume of the flow path part 5 is reduced, the dispersion of the dynamic pressure applied to the exhaust gas taken in from the intake port 3 can be reduced.
(3) Third, as shown in FIG. 5A to FIG. 5D, the outer cylindrical portion on the lower side of the central shaft 91 (the side opposite to the side where the intake port 3 is provided as viewed from the central shaft 91). It is good also as a shape which folded the edge part of the other side of 21 to the part close | similar to the central axis 91 of the inner side cylindrical part 20.

However, the area shown in FIG. 5D may be formed so that the flow path cross-sectional area of the flow path portion 5 is larger than the opening area of the ejection port 4.
(4) Fourth, the spout 4 is not only a hole formed by a space formed between the overlap part 24 and the inner cylindrical part 20 as in the above-described embodiment, but also FIG. 6A to FIG. 6D may be adopted. Like FIG.6B, the jet nozzle 4 is good also as a form which arranged the circular-arc-shaped hole along the predetermined | prescribed circle. As shown in FIG. 6C, the spout 4 may have a shape in which a plurality of circular holes are arranged along a predetermined circle. As shown in FIG. 6D, the spout 4 is formed by combining FIG. 6B and FIG. 6C, and arranging two arc-shaped holes and a plurality of circular holes along a predetermined circle. Also good. Moreover, the number of the jet nozzles 4 may be any number, and the interval may be any interval. Moreover, the jet nozzle 4 is not only formed in a circular shape or an elliptical shape, but may be formed in any shape such as a polygonal shape. Furthermore, the jet nozzle 4 does not necessarily have a shape arranged along a circle.

In order to provide the spout 4 having such a shape, as shown in FIG. 6A, a ring-shaped plate member 40 having a predetermined width in the radial direction is used, and the outer peripheral edge portion of the plate member 40 is an inner cylindrical portion. If it installs in the dosing pipe 1 so that it may contact | abut to the edge part of 20 and the cylindrical surface of the outer side cylindrical part 21 by which the inner edge part was turned back, and each hole mentioned above should be provided in the board | plate material 40, Good.
(5) Fifth, the folded portion of the outer cylindrical portion 21 may be configured as shown in FIG. 7A or FIG. 7B.

Specifically, as shown in FIG. 7A, the outer tubular portion 21 may be folded back so short that the overlap portion 24 does not occur.
Also, as shown in FIG. 7B, the length of the overlap portion 24 is such that the portion on the opposite side is shorter than the portion on the intake port 3 side when viewed from the central axis 91. A portion formed by folding may be formed.
(Second Embodiment)
Next, a second embodiment will be described.

As shown in FIG. 8, the dosing pipe 1 of the second embodiment is formed in a cylindrical shape and has one end formed with an opening 22 that opens to the exhaust downstream side when attached to the exhaust pipe h. On the inner wall surface on the other end side opposite to the side, a blow-in portion 26 is provided along the circumferential direction.

The blow-in part 26 was formed by folding the other end of the main body part 2 inward.
And when it sees the side of the other end part of the main-body part 2 through the opening part 22 through the opening part 22, it is the spout 4 which opens toward the opening part 22 in the side surface which opposes the opening part 22. Is formed.

The main body 2 is attached to the exhaust pipe h so that the opening 22 faces the exhaust downstream side.
The urea water is injected from the injection port 9 provided in the center portion of the rear opening 23 on the side where the blowing portion 26 is provided, and is injected from the opening 22 toward the catalyst through the main body 2. .

Moreover, in 2nd Embodiment, the dosing pipe 1 is provided with the pipe part 10, and one opening of the pipe part 10 opens in the exhaust pipe h of the exhaust_gas | exhaustion upstream rather than the opening part 22, and the other opening is It installs so that it may open in the blowing part 26. FIG.

One opening of the pipe portion 10 becomes the intake port 3, and the flow passage portion 5 extending from the intake port 3 toward the blowing portion 26 is formed by installing the pipe portion 10.
(Characteristic effects of the second embodiment)
When the dosing pipe 1 described above is used, the main body portion 2 may have a single tube structure as compared with the dosing pipe 1 of the first embodiment, and the blowing portion 26 is formed in the main body portion 2 of the single tube structure. The main body 2 is attached to the exhaust pipe h, and the pipe 10 is only attached to the exhaust pipe h.

Therefore, when the dosing pipe 1 of the second embodiment is used, the main body 2 having a simple structure is formed without forming the main body 2 having a complicated structure, and this is attached to the exhaust pipe h. The dosing pipe 1 can be attached to the exhaust pipe h simply by attaching to the exhaust pipe h.

In addition, about the jet nozzle 4 formed in the blowing part 26, you may provide in the position nearest to the central axis 91 of the main-body part 2, as shown in FIG.
[Other Embodiments]
Although the embodiment has been described above, it is needless to say that the invention described in the claims is not limited to the above embodiment and can take various forms.

(1) In the said embodiment, although the catalyst was illustrated as a to-be-injected body, it is not restricted to this. Moreover, although urea water was illustrated as a reducing agent, it is not restricted to this.
(2) In the above embodiment, both end portions of the outer cylindrical portion 21 are folded and joined to the inner cylindrical portion 20, or the overlap portion 24 is formed, but other members constituting the folding are prepared, This may be constructed by welding to the end of the outer cylindrical portion 21.

Claims

A dosing pipe that is attached to an exhaust pipe and used.
A main body that forms a cylindrical injection passage having an opening that opens inside the exhaust pipe;
An intake opening that opens toward the exhaust upstream side of the exhaust pipe inside the exhaust pipe on the exhaust upstream side of the opening;
When the inside of the injection path is viewed through the opening, an air curtain is provided at a position that surrounds an injection range in which an injection material is injected in a cone shape in the injection path, and surrounds the injection range toward the opening. A spout for ejecting the exhaust gas to be formed;
The flow passage section has a larger flow passage cross-sectional area than the opening area opened toward the opening, and the flow passage section guides the exhaust gas taken in at the intake opening to the jet outlet.
A dosing pipe characterized by comprising:
The dosing pipe according to claim 1, wherein
The main body is formed in a double tubular shape having an inner cylindrical portion and an outer cylindrical portion,
The intake port is formed in the outer cylindrical portion,
The spout is located inside the inner cylindrical portion when the inside of the jet passage is viewed through the opening,
The flow path portion is formed by a space between the inner cylindrical portion and the outer cylindrical portion, and the exhaust gas flowing from the intake port is directed in a direction from the jet port toward the opening portion. A dosing pipe comprising a direction changing portion for changing the direction.
The dosing pipe according to claim 2,
Having an overlap portion that is folded back to a position where the end of the outer cylindrical portion opposite to the side where the opening is provided covers the inner cylindrical portion;
The dosing pipe, wherein the jet port is formed in the overlap portion.
In the dosing pipe according to claim 2 or 3,
The intake is
A dosing pipe, wherein the dosing pipe is provided at a position close to the opening.
The dosing pipe according to any one of claims 2 to 4,
The main body is
The length along the central axis of the main body portion, the length of the opposite side across the central axis with respect to the side where the intake port is provided is on the side where the intake port is provided The dosing pipe, wherein an opening surface of the opening portion is inclined with respect to the central axis so as to be shorter.
The dosing pipe of claim 1,
The main body is
On the inner wall surface on the end side opposite to the end side on which the opening is formed, there is a blowing portion provided along the circumferential direction, and when the blowing portion is viewed through the opening, The spout opening that opens toward the opening side,
A dosing pipe, comprising: a pipe portion that extends from the intake port that opens upstream from the opening portion toward the blow-in portion and forms the flow passage portion.
The dosing pipe according to any one of claims 1 to 6,
The main body is
A dosing pipe, wherein the dosing pipe is formed in a shape whose diameter increases toward the opening.
The dosing pipe according to any one of claims 1 to 7,
The spout is
A dosing pipe comprising a slit formed in a ring shape.
The dosing pipe according to any one of claims 1 to 7,
The spout is
A dosing pipe having a shape in which a plurality of holes are arranged in a circle.