GB2552672A

GB2552672A - SCR doser spray atomization

Info

Publication number: GB2552672A
Application number: GB1613306.8A
Authority: GB
Inventors: R Panteny Simon
Original assignee: Delphi International Operations Luxembourg SARL
Current assignee: Delphi International Operations Luxembourg SARL
Priority date: 2016-08-02
Filing date: 2016-08-02
Publication date: 2018-02-07
Also published as: GB201613306D0

Abstract

A selective catalytic reduction (SCR) doser 10, is adapted to spray a reagent into a tailpipe of an internal combustion engine, said doser 10 having a body 12, in which is arranged a valve member 16, which is adapted to open or to close a valve seat 18, arranged on an inner face 24 of a transverse wall 20 of the body. The said valve seat 18 controlling an outlet opening 22. The SCR doser 10 is further provided with a cavity C1 arranged in said outlet passage 22, the said cavity C1 disrupting the reagent flow and thereby causing turbulences. Further feature may include a diffuser plate D, having a first face arranged in surface contact with the outer face 26, and an opposed second face 36, the first plate having at least one through path opening 38, and the second face a through opening enabling the reagent to exit the body.

Description

(71) Applicant(s):

Delphi International Operations Luxembourg S.a.r.l. Avenue de Luxembourg, Bascharage L-4940, Luxembourg (72) Inventor(s):

Simon R Panteny (56) Documents Cited:

DE102013201453A1 DE 102010039079 A1 JP 2015206333 A US 20020092930 A1 (58) Field of Search:

INT CL B05B, F01N Other: WPI & EPODOC

DE 102012211665A1 DE 102008040822 A1 US 20130099015 A1 (74) Agent and/or Address for Service:

DELPHI FRANCE SAS

PO Box CS 65059, Bat. Le Raspail,

ZAC Paris Nord II 22, avenue des Nations,

Roissy CDG Cedex 95972,

France (including Overseas Departments and Territori es) (54) Title of the Invention: SCR doser spray atomization Abstract Title: SCR doser spray atomization (57) A selective catalytic reduction (SCR) doser 10, is adapted to spray a reagent into a tailpipe of an internal combustion engine, said doser 10 having a body 12, in which is arranged a valve member 16, which is adapted to open or to close a valve seat 18, arranged on an inner face 24 of a transverse wall 20 of the body. The said valve seat 18 controlling an outlet opening 22. The SCR doser 10 is further provided with a cavity C1 arranged in said outlet passage 22, the said cavity C1 disrupting the reagent flow and thereby causing turbulences. Further feature may include a diffuser plate D, having a first face arranged in surface contact with the outer face 26, and an opposed second face 36, the first plate having at least one through path opening 38, and the second face a through opening enabling the reagent to exit the body.

26,28

T32

FIG. 1

CP

26,28

40, C2

FIG. 2

FIG. 4

FIG. 5

2/2

X

FIG. 9

FIG. 10

SCR DOSER SPRAY ATOMIZATION

TECHNICAL FIELD

The present invention relates to a selective catalytic reduction doser and more particularly to an arrangement enabling further spray and atomization of the expelled fluid reagent.

BACKGROUND OF THE INVENTION

A selective catalytic reduction (SCR) doser consists of a valve member that controls the flow of a chemical, or reagent such as urea aqueous fluid, that will reduce the nitrous oxides exiting the tailpipe. While the valve controls the flow of this chemical the efficiency is dependent upon the distribution of the chemical generated within the exhaust in order to improve mixing and chemical interaction.

It is becoming important that not only the amount of liquid injected by a SCR doser is controlled, but also the level of atomisation of the spray. A spray with a greater atomisation improves the efficiency of the SCR system, thus reducing the amount of urea to be carried.

The orifices through which fluid urea is injected above atmospheric pressure defines the spray and, depending on the positioning of the spray orifices, in relation to the valve controlling flow, the degree of atomization can be adjusted but, depending on the number of spray orifices current designs can suffer from insufficient atomization and inconsistent spray behavior from one spray hole to another.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to resolve the above mentioned problems in providing a selective catalytic reduction (SCR) doser adapted to spray a reagent in a tailpipe of an internal combustion engine, said doser having a body defining a peripheral wall surrounding an inner volume within which is arranged a valve member adapted to move along a main axis in order to open or to close a valve seat arranged on an inner face of a transverse wall of the body, said valve seat controlling an outlet opening through said transverse wall.

The SCR doser is further provided with a cavity arranged in said outlet passage, said cavity disrupting the reagent flow and causing turbulences.

Also, in a closed position of the valve seat, the valve member contacts the valve seat along a sealing area forming closed line, the outlet passage opening within said closed line. A first cavity is defined within the thickness of the transverse wall between said sealing closed line and an outer face of the transverse wall, opposed to the inner face.

Also, said valve seat, arranged on an inner face of the transverse wall, is tapered and said outer face is planar, the first cavity being a cylindrical volume the opening of which forms a disc in the outer face of the transverse face and wherein, the SCR doser further comprises a first diffuser plate having a first face arranged in surface contact against said outer face and, an opposed second face, said first plate being provided with at least one through path opening in the first face at a first end arranged within said disc opening and, in the second face at a second end, thus defining a first fluid communication enabling reagent to exit the body of the doser via the first cavity C and said through path.

Also, said first plate is provided with a plurality of through path.

Also, said through path comprises an entry portion extending from the first end to an intermediate junction area wherefrom depart an exit portion extending to the second end, said entry portion being dug within the first face and radially extending on said first face.

Also, the entry portion is an annular recess dug in the first face of the first plate, said annular recess being radially bounded between an inner edge smaller than the disc opening of the first cavity and, an outer edge larger than said disc opening, the intermediate junction area being in the vicinity of said outer edge, said annular recess being partially covered by the outer face of the transverse wall.

Also, the entry portion comprises a collecting area smaller than the disc opening D and, a plurality of grooves also dug in said first face and outwardly extending from said collecting area to said distant junction area, the grooves being partially covered by the outer face of the transverse wall.

Also, the collecting area is a disc-shape recess dug in said first face of the first plate, said recess being smaller than the disc opening of the first cavity.

Also, the collecting area is an annular groove dug in said first face of the first plate, said annular groove being of a smaller size than the disc opening of the first cavity.

Also, the SCR doser further comprises a second diffuser plate provided with at least one another through path extending between a first face and an opposed second face, and defining a second cavity C between said first and second plates.

Also, the first fluid communication is defined between the first cavity and the second cavity.

Also, said another through path arranged in the second plate further define a second fluid communication enabling, in use, fluid to exit the second cavity and be expelled out of the second face of the second plate.

Also, said second cavity is defined by a recess dug in the first face of the second plate.

Also, said second cavity is defined by a recess dug in the second face of the first plate.

Also, the second plate is arranged at a distance from the first plate, the second cavity being defined between the second face of the first plate and the first face of the second plate.

Also, the through path arranged within the first plate and said another through path arranged with the second plate are misaligned.

Also, the through path arranged within the first plate and said another through path arranged with the second plate are aligned.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now described by way of example with reference to the accompanying drawings in which:

Figure 1 is an axial section of a first embodiment of a SCR doser provided with a first outer plate.

Figures 2, 3, 4 and 5 are top views of four alternatives of the first outer plate of figure 1.

Figure 6 is an axial section of a second embodiment of a SCR doser provided with two outer plates.

Figures 7, 8, 9, 10 are axial sections of four alternatives of the two plates of figure 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In reference to figure 1 is sketched a partial section of a selective catalytic reduction, hereafter SCR, doser 10 adapted to be arranged on a tailpipe, not represented. The doser 10 comprises a body 12 having a peripheral wall 14 surrounding an inner space S, in which is slidably arranged a valve member 16 adapted to move along a main axis X between a closed position CP and an open position OP of a valve seat 18.

The peripheral wall 14 comprises a transverse wall 20 in the center of which is defined an outlet opening 22, the transverse wall 20 having an inner face 24 oriented inside said inner space S and an opposed outer face 26 oriented toward the tailpipe, the outlet 22 opening in a circular disc D in the outer face 26. As visible on the figure, the valve seat 18 comprises a tapered face 28 provided on the inner face 24, said tapered valve face 28 opening in said outlet opening 22 thus defining a first cavity Cl in the thickness of the transverse wall comprised between the inner 24 and the outer 26 faces. A complementary movable seat face 30 of the valve member 16 which, in the exemplary embodiment presented is a spherical ball but another shape such as a male conical face, could also be utilized to cooperate with the tapered face 28.

In closed position CP, the ball face 30 contacts the tapered face 28 along a closed circular sealing line preventing a pressurized reagent R present in the inner space S to be sprayed via the outlet opening 22 and, in open position OP, the ball face 30 lifts away from the tapered face 28 opening a passage between the inner space S and the outlet opening 22 and enabling reagent spray.

In a first embodiment of the doser as presented on figure 1, the doser 10 further comprises a diffuser plate 32 fixed to the body 12, said diffuser plate 32 having a thickness T32 measured between a first face 34 arranged in surface contact against the outer face 26 of the transverse wall and, an opposed second face 36 oriented toward the tailpipe. The diffuser plate 32 is provided with a through path 38 creating a first fluid communication through said plate 32. The through path 38 comprise an entry portion 40, an intermediate junction area 42 and an exit portion 44, the entry portion extending from a first end 46 that is in the first face 34 to the intermediate junction area 42 wherefrom depart the exit portion 44 extending to a second end 48 opening in the second face 36. The through path 38 is of a much thinner section than the disc D opening of the outlet 22 so the diffuser plate 32 restricts the outlet section and facilitates the spray. Also, the first end 46 of the through path 38 opens in the disc D of the outlet 22.

Figures 2, 3, 4 and 5 present top views of four alternatives of diffuser plate 32, said top views presenting the first face 34 of the plate.

In a first alternative represented on figure 2, the entry portion 40 is an annular recess dug in the first face 34, in the thickness T32 of the plate. Said recess is radially bounded between a circular inner edge 50 that is smaller than the opening disc D of the outlet and, a circular outer edge 52 much larger than said opening disc D. The exit portion 44 comprises three small orifices 54 extending between the bottom of the recess, near the outer edge 52, said area forming for this alternative the intermediate junction area 42 and, the second end 48 that open in the second face 36 of the plate. This diffuser plate 32 being fixed in place in the doser body, the recess that is mostly covered by the transverse wall 20 forms a second cavity C2 which is open to the first cavity Cl via a non-covered annular portion of the recess surrounding the inner edge 50, said non-covered annular portion forming the first end 46 of the through path 38. In open position OP of the valve seat 18, the reagent R flows from the inner space S to the first cavity Cl then, via the annular first end 46 into the second cavity C2 then, the reagent is expelled into the tailpipe via the orifices 54. The changes of direction and the cavities disrupt the reagent flow creating turbulences and favoring atomization of the reagent in the exhaust gases.

In a second alternative presented on figure 3, the entry portion 40 comprises a small recess forming the second cavity C2 from which outwardly depart grooves 56 dug in the first face 34 of the plate and extending in a curved profile to an extremity forming said intermediate junction area 42 where from axially connect the orifice 54 opening in the second face 36 of the plate.

In a third alternative presented on figure 4, the first end 46 of the entry portion 40 is an annular groove dug in the first face 34 of the plate, three curved grooves 56, similar to the second embodiment, extending from said annular groove.

In a fourth embodiment presented on figure 5, the first end 46 remains an annular groove similar to the third embodiment. To connect said annular first end groove 46 to the exit portion 44, a surrounding second groove 58 is dug concentric and surrounding the annular first end groove and, intermediate radial passage interconnect the first groove to the second groove and, the second groove to the orifices 54 of the exit portion 44.

In these four alternatives to the first embodiment, a common feature is the diffuser plate 32 which first face is provided with an entry portion 44 forming the second cavity C2.

Further alternative of diffuser plates are of course possible varying for instance, the curved or angular profiles of the groove, or the number of exit orifices.

In a second embodiment of the doser 10 presented on figure 6, in addition to the first diffuser plate 32, the doser 10 comprises a second diffuser plate 60 arranged parallel to the first plate 32. Said second plate 60 also has a first face 62 oriented toward the first plate 32 and a second face 64 oriented toward the tailpipe. The through path 38 enabling reagent spray comprises first orifices 66 provided through the first plate 32, a second cavity C2 arranged between the first plate 32 and the second plate 60 and, second orifices 68 provided through the second plate 60.

Four alternatives to this second embodiment are now presented in axial section. In a first alternative, figure 7, the first plate 32 and the second plate 60 are arranged distant from each other defining the second cavity C2 between them. The first orifices 66 open in the first face 34 of the first plate within the opening disc D of the outlet and, the second orifices 68 extend axially or at an angle through the second plate 60 are further radially spaced.

A second alternative, figure 8, is quite similar to the first alternative to the point that the first 32 and second 60 diffuser plates are identical, the first 66 and second 68 orifices being aligned and, still defining the second cavity C2 between the plates.

In a non-represented alternative to this second alternative, the first 32 and second plate 60, although being identical with the first 66 and second 68 orifices opening at same radial distance from the main axis X, could be angularly offset which would misaligned the orifices.

A third alternative, figure 9, is similar to the first alternative, figure 7, to the exception that, the second face 36 of the first plate and the first face 62 of the second plate are in surface contact, the second cavity C2 being defined by an annular recess dug in the second face 36 of the first plate, alternatively in the first face of the second plate.

A fourth alternative, figure 10, is similar to the second alternative, figure 8, to the exception that, the second face 36 of the first plate and the first face 62 of the second plate are in surface contact, the second cavity C2 comprising a plurality of second cavities C2 each defined by a recess dug, at the intersection of the first and second orifices, in the second face 36 of the first plate, alternatively in the first face of the second plate, the aligned first 66 and second 68 orifices passing through said second opening C2. Also, said second cavity C2 could take the form of an annular recess through which communicate all the first and second orifices. In this latter case the first and second plate could be angularly offset and the first and second orifices be misaligned.

In any alternative, the reagent exiting the doser 10, enters the first cavity Cl, passes through the first orifices 66 and get in the second cavity C2 prior to exiting the doser by passing through the second orifices 68.

LIST OF REFERENCES

X	main axis
s	inner space
CP	closed position
OP	open position
D	disc opening of the outlet in the outer face
R	reagent
Cl	first cavity
C2	second cavity
T32	thickness of the diffuser plate

SCR doser body peripheral wall valve member valve seat transverse wall outlet inner face of the transverse wall outer face of the transverse wall tapered face movable seat face first diffuser plate first face of the diffuser plate second face of the diffuser plate through path entry portion intermediate junction area exit portion first end second end circular inner edge circular outer edge orifice groove

8 annul ar groove second diffuser plate first face of the second plate second face of the second plate first orifice second orifice

Claims

CLAIMS:

1. Selective catalytic reduction (SCR) doser (10) adapted to spray a reagent (R) in a tailpipe of an internal combustion engine, said doser (10) having a body (12) defining a peripheral wall surrounding an inner volume (S) within which is arranged a valve member (16) adapted to move along a main axis (X) in order to open or to close a valve seat (18) arranged on an inner face (24) of a transverse wall (20) of the body, said valve seat (18) controlling an outlet opening (22) through said transverse wall, characterized in that the SCR doser (10) is further provided with a cavity (Cl, C2) arranged in said outlet passage (22), said cavity (Cl, C2) disrupting the reagent flow and causing turbulences.

2. SCR doser (10) as claimed in the preceding claim wherein, in a closed position (CP) of the valve seat (18), the valve member (16) contacts the valve seat along a sealing area forming closed line, the outlet passage (22) opening within said closed line, a first cavity (Cl) being defined within the thickness of the transverse wall (20) between said sealing closed line and an outer face (26) of the transverse wall, opposed to the inner face (24).

3. SCR doser (10) as claimed in claim 2 wherein said valve seat (18) arranged on an inner face (24) of the transverse wall is tapered and said outer face (26) is planar, the first cavity (Cl) being a cylindrical volume the opening of which forms a disc (D) in the outer face (26) of the transverse face and wherein, the SCR doser (10) further comprises a first diffuser plate (32) having a first face (34) arranged in surface contact against said outer face (26) and, an opposed second face (36), said first plate (32) being provided with at least one through path (38) opening in the first face (34) at a first end (46) arranged within said disc opening (D) and, in the second face (36) at a second end (48), thus defining a first fluid communication enabling reagent to exit the body of the doser via the first cavity (Cl) and said through path (38).

4. SCR doser (10) as claimed in claim 3 wherein said first plate (32) is provided with a plurality of through path (38).

5. SCR doser (10) as claimed in any one of the claims 3 or 4 wherein said through path (38) comprises an entry portion (40) extending from the first end (46) to an intermediate junction area (42) wherefrom depart an exit portion (44) extending to the second end (48), said entry portion (40) being dug within the first face (34) and radially extending on said first face.

6. SCR doser (10) as claimed in claim 5 wherein the entry portion (40) is an annular recess dug in the first face (34) of the first plate, said annular recess being radially bounded between an inner edge (50) smaller than the disc opening (D) of the first cavity (Cl) and, an outer edge (52) larger than said disc opening (D), the intermediate junction area (42) being in the vicinity of said outer edge (52), said annular recess being partially covered by the outer face (26) of the transverse wall.

7. SCR doser (10) as claimed in the combination of claims 5 and 4 wherein the entry portion (40) comprises a collecting area smaller than the disc opening (D) and, a plurality of grooves (56) also dug in said first face and outwardly extending from said collecting area to said distant junction area (42), the grooves (56) being partially covered by the outer face (26) of the transverse wall.

8. SCR doser (10) as claimed in claim 5 wherein the collecting area is a disc-shape recess dug in said first face (34) of the first plate, said recess being smaller than the disc opening (D) of the first cavity (Cl).

9. SCR doser (10) as claimed in claim 5 wherein the collecting area is an annular groove (58) dug in said first face (34) of the first plate, said annular groove (58) being of a smaller size than the disc opening (D) of the first cavity.

10. SCR doser (10) as claimed in any one of the claims 3 or 4 further comprising a second diffuser plate (60) provided with at least one another through path extending between a first face (62) and an opposed second face (64), and defining a second cavity (C2) between said first and second plates.

11. SCR doser (10) as claimed in claim 10 wherein the first fluid communication is defined between the first cavity (Cl) and the second cavity (C2).

12. SCR doser (10) as claimed in claim 11 wherein said another through path arranged in the second plate (60) further define a second fluid communication enabling, in use, fluid to exit the second cavity (C2) and be expelled out of the second face (64) of the second plate.

13. SCR doser (10) as claimed in any one of the claims 10 to 12 wherein said second cavity (C2) is defined by a recess dug in the first face (62) of the second plate.

14. SCR doser (10) as claimed in any one of the claims 10 to 13 wherein said second cavity (C2) is defined by a recess dug in the second face (36) of the first plate (32).

15. SCR doser (10) as claimed in any one of the claims 10 to 12 wherein the second plate (60) is arranged at a distance from the first plate (32), the second cavity (C2) being defined between the second face (36) of the first plate and the first face (62) of the second plate.

16. SCR doser (10) as claimed in any one of the claims 10 to 15 wherein the through path arranged within the first plate and said another through path arranged with the second plate are misaligned.

17. SCR doser (10) as claimed in any one of the claims 10 to 15 wherein the through path arranged within the first plate (32) and said another through path arranged with the second plate (60) are aligned.

Intellectual

Property

Office

Application No: GB1613306.8 Examiner: Mr Charles Ellwood