U.S. patent application number 12/989769 was filed with the patent office on 2011-02-17 for exhaust element comprising a static means for mixing an additive into the exhaust gases.
This patent application is currently assigned to Faurecia Systemes D'Echappement. Invention is credited to Cedric Collinot.
Application Number | 20110036082 12/989769 |
Document ID | / |
Family ID | 40091809 |
Filed Date | 2011-02-17 |
United States Patent
Application |
20110036082 |
Kind Code |
A1 |
Collinot; Cedric |
February 17, 2011 |
EXHAUST ELEMENT COMPRISING A STATIC MEANS FOR MIXING AN ADDITIVE
INTO THE EXHAUST GASES
Abstract
The invention relates to an exhaust element including a line for
exhausting the gases of a motor vehicle with a combustion engine
and through the inside of which flows a fluid with the exhaust
gases and of an additive to these gases. The exhaust element has,
mounted inside it, a static device for mixing this additive with
these exhaust gases. The static device for mixing the additive with
the exhaust gases comprises at least one helicoid having an axis
extending in a direction that makes a set angle with the direction
of flow of the fluid through this exhaust element.
Inventors: |
Collinot; Cedric; (Toulouse,
FR) |
Correspondence
Address: |
Andrew W. Chu, PC
P. O. Box 2925
Houston
TX
77252-2925
US
|
Assignee: |
Faurecia Systemes
D'Echappement
Nanterre
FR
|
Family ID: |
40091809 |
Appl. No.: |
12/989769 |
Filed: |
April 23, 2009 |
PCT Filed: |
April 23, 2009 |
PCT NO: |
PCT/FR09/50755 |
371 Date: |
October 26, 2010 |
Current U.S.
Class: |
60/324 |
Current CPC
Class: |
F01N 2240/20 20130101;
B01F 5/0614 20130101; B01F 2005/0639 20130101; Y02A 50/20 20180101;
Y02A 50/2322 20180101; F01N 3/2892 20130101 |
Class at
Publication: |
60/324 |
International
Class: |
F01N 1/00 20060101
F01N001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 29, 2008 |
FR |
0852893 |
Claims
1. Exhaust element comprising: a line for exhausting the gases of a
motor vehicle with a combustion engine and through the inside of
which flows a fluid being comprised of the exhaust gases as well as
of an additive to these gases, a static means mounted inside the
exhaust element, for mixing this additive with these exhaust gases,
wherein the static means for mixing the additive with the exhaust
gases comprises at least one helicoid having an axis extending in a
direction forming a set angle with the direction of flow of the
fluid through this exhaust element.
2. Exhaust element according to claim 1, wherein the helicoid has
an increasing width, in the direction of flow of the fluid through
the exhaust element.
3. Exhaust element according to claim 1, wherein the helicoid has a
decreasing width, in the direction of flow of the fluid through the
exhaust element.
4. Exhaust element according to claim 1, wherein the direction of
extension of the axis of a helicoid forms, with the direction of
flow of the fluid through the exhaust element, an angle between 0
and 30.degree..
5. Exhaust element according to claim 1, further comprising: a
mixer comprised of a plurality of helicoids, each helicoid having
an axis, extending in a direction forming a set angle, in
particular between 0 and 30.degree., with the direction of
extension of the axis of another helicoid and extending in a
direction forming a set angle, in particular between 0 and
30.degree., with the direction of flow of the fluid through this
exhaust element.
6. Exhaust element according to claim 5, wherein the helicoids are
arranged so that their extension axes diverge, in the direction of
flow of the fluid through the exhaust element.
7. Exhaust element according to claim 5, wherein the helicoids are
arranged so that their extension axes converge, in the direction of
flow of the fluid through the exhaust element.
8. Exhaust element according to claim 5, wherein the axes of
helicoids are arranged according to a matrix, in particular a
regular one, with respect to the geometry of the section of the
exhaust element.
9. Exhaust element according to claim 5, wherein two immediately
juxtaposed helicoids have the same direction of rotation.
10. Exhaust element according to claim 5, wherein two immediately
juxtaposed helicoids have an opposite direction of rotation.
11. Exhaust element according to claim 5, wherein the mixer
comprises a plurality of helicoids and wherein these helicoids are
grouped together inside at least one set comprising at least two
helicoids having preferably the same direction of rotation.
12. Exhaust element according to claim 5, wherein the mixer
comprises at least one module comprising a plate oriented parallel
to the direction of flow of the fluid through the exhaust element
and at least one or a set of at least two helicoids extending in
the extension downstream of said plate.
13. Exhaust element according to claim 12, wherein the mixer
comprises a plurality of modules, each module comprising a plate as
well as a set of at least two helicoids and assembled, two by two,
in particular perpendicularly, through assembling means at least
one plate of at least one such module includes.
14. Exhaust element according to claim 13, wherein a module
comprises, at the level of at least one of the lateral edges of a
plate of said module, a wing located in the extension of said plate
and oriented in the direction of another wing the plate of another
module comprises, wherein said wing is made integral with, in
particular by welding.
15. Exhaust element according to claim 12, wherein the module
comprises a single part, in particular a metallic part, preferably
made by cutting out, boring, in particular complemented by
folding.
16. Exhaust element according to claim 5, wherein the exhaust
element comprises a means for receiving the mixer.
17. Exhaust element according to claim 1, wherein the exhaust
element comprises either of an exhaust conduit comprising, inside,
the means for mixing an additive with the exhaust gases, or of a
device for the physical and/or chemical treatment of exhaust gases
comprising, inside, the means for mixing an additive with the
exhaust gases as well as, downstream of this mixer, a means for the
physical and/or chemical treatment of this mixture.
Description
RELATED U.S. APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO MICROFICHE APPENDIX
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] This invention relates to an exhaust element included in a
line for exhausting the gases from a motor vehicle with a
combustion engine.
[0006] This invention is related to the field of the automobile
industry and, in particular, that of manufacturing equipment
designed to ensure the exhausting of gases obtained from the
burning of a fuel inside a combustion engine a motor vehicle
includes.
[0007] Such equipment adopts the form of an exhaust line that,
according to the direction of the flow of the exhaust gases in this
exhaust line, on the one hand, is connected to such a combustion
engine, on the other hand, comprises a succession of exhaust
elements and, on yet another hand, opens onto the atmosphere.
[0008] In particular, among these exhaust elements, said exhaust
line comprises at least one device for the physical and/or chemical
treatment of exhaust gases.
[0009] Such a device may consist of a catalytic converter that can
assume the form of a catalytic converter (in particular of the SCR
type) for reducing nitrous oxides (NOx) and that comprises a means
for treating the gases at least designed to ensure such a
reduction. Such a catalytic converter finds its application in
particular when it is necessary to clean up exhaust gases obtained
from the burning of a fuel of the diesel type.
[0010] 2. Description of Related Art Including Information
Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
[0011] It was found that the reduction of these exhaust gases
inside such a catalytic converter is considerably improved when,
before their introduction into this catalytic converter, these
exhaust gases are mixed with an additive containing urea. In fact,
urea, when it is introduced into hot exhaust gases (in particular
after vaporization of a water solution of urea), undergoes a
chemical transformation transforming it into ammonia (NH3)
constituting a powerful reducer of nitrous oxides. Thus, inside the
catalytic converter and in the presence of this ammonia, exhaust
gases are reduced so that, at the exit of this catalytic converter,
essentially water, hydrogen (H2) and nitrogen (N2) are
released.
[0012] In this connection, it should be noted that the more
homogeneous the mixing of the additive with exhaust gases is, the
more effective is the reduction of these nitrous oxides.
[0013] In order to improve the homogeneity of this mixture, it is
common to resort to a static mixer placed inside an exhaust element
(usually an exhaust conduit) and upstream of the means for treating
the gases.
[0014] As described in WO9300990, such a mixer adopts the form of a
plurality of deflection elements that are, on the one hand,
arranged according to a plurality of rows perpendicular to the axis
of symmetry of the exhaust element and, on the other hand, oriented
in the same direction inside the same row and in the opposite
direction in two adjoining rows.
[0015] Also known, from EP-1.514.591, is an exhaust element
comprising, inside, a static mixer comprising a plurality of
zigzags adopting the form of bent strips of sheet metal extending
from the periphery of this element toward its center. These zigzags
define propeller blades extending through the exhaust element.
[0016] These devices permit, of course, to improve the homogeneity
of the mixture downstream of the mixer but have however the
disadvantage of creating a considerable back pressure upstream of
this mixer, prejudicial to the flow of the gases in the exhaust
line as well as to their treatment and to their evacuation.
SUMMARY OF THE INVENTION
[0017] This invention claims to be able to remedy the disadvantages
of the state-of-the-art devices.
[0018] To this end, the invention relates to an exhaust element
included in a line for exhausting the gases from a motor vehicle
with a combustion engine and through the inside of which flows a
fluid consisting of the exhaust gases as well as of an additive to
these gases, this exhaust element comprising, mounted inside it, a
static means for mixing this additive with these exhaust gases.
This exhaust element is characterized in that the static means for
mixing the additive with the exhaust gases comprises at least one
helicoid having an axis extending in a direction that forms a set
angle with the direction of flow of the fluid through this exhaust
element.
[0019] An additional feature relates to the fact that the direction
of extension of the axis of a helicoid forms, with the direction of
flow of the fluid through the exhaust element, an angle between 0
and 30.degree..
[0020] According to another feature, the mixer comprises a
plurality of helicoids having each an axis, on the one hand,
extending in a direction that makes a set angle, in particular
between 0 and 30.degree., with the direction of extension of the
axis of another helicoid and, on the other hand, extending in a
direction that makes a set angle, in particular between 0 and
30.degree., with the direction of flow of the fluid through this
exhaust element.
[0021] According to an additional feature, the two helicoids that
are immediately juxtaposed have an identical or, preferably,
opposite direction of rotation.
[0022] An additional feature consists in that the mixer comprises a
plurality of helicoids and that these helicoids are grouped
together inside at least one set comprising at least two helicoids
the direction of rotation of which is preferably identical.
[0023] According to another feature, the mixer comprises at least
one module comprising, on the one hand, a plate oriented parallel
to the direction of flow of the fluid through the exhaust element
and, on the other hand, at least one helicoid or a set of at least
two helicoids extending in the extension downstream of this
plate.
[0024] In fact, this mixer comprises a plurality of modules, on the
one hand, comprising each a plate as well as a set of at least two
helicoids and, on the other hand, assembled, two by two, in
particular perpendicularly, through assembling means comprised by
at least one plate of at least one such module.
[0025] Finally, such a module consists of a single part, in
particular a metallic part, preferably made by cutting out, boring,
in particular completed by folding.
[0026] In fact, this exhaust element consists either of an exhaust
conduit comprising, inside, the means for mixing an additive with
the exhaust gases, or of a device for the physical and/or chemical
treatment of exhaust gases comprising, inside, the means for mixing
an additive with the exhaust gases as well as, downstream of this
mixer, a means for the physical and/or chemical treatment of this
mixture.
[0027] The invention also relates to an exhaust line comprising
such an exhaust element.
[0028] The advantages of this invention consist in that the exhaust
element comprises a static mixer for mixing the additive with the
exhaust gases, such a mixer consisting of at least one helicoid
placed inside this exhaust element. Such a helicoid permits,
advantageously, to confer to the fluid a turbulent movement
improving the homogenization of the mixture. Another advantage of
such a helicoid consists in that the fluid, downstream of this
helicoid, has a flow such that the back pressure generated by the
mixture additive/exhaust gases is substantially lower than that
generated by the state-of-the-art devices.
[0029] Additionally, such a mixer can also include a plurality of
helicoids that are in fact cleverly arranged inside the exhaust
element so as to adapt to the geometry and/or to the dimensions of
the exhaust element which advantageously permits to optimize the
flow of the fluid downstream of this mixture means.
[0030] Additionally, it is easily possible to adapt the number of
helicoids, their positioning with respect to each other, their
characteristics (direction of rotation, length, pitch, diameter,
axis orientation), which advantageously permits to obtain good
results in terms of homogeneity of the mixing and of weakness of
the back pressure (and even in terms of compromise between this
back pressure and head loss) downstream of the mixer.
[0031] In this connection, it should be noted that good results are
obtained when this mixer comprises at least one pair of helicoids,
and even preferably two pairs of helicoids.
[0032] An additional feature consists in that said mixer is placed
inside an exhaust element consisting of an exhaust conduit or of a
gas treatment device, in particular, a catalytic converter. Such an
embodiment advantageously permits to position said mixer in an
optimized manner within the exhaust line, with respect to the means
for introducing the additive and with respect to the means for
treating the exhaust gases.
[0033] Finally, this mixer can be made from at least one metal
sheet, in particular by cutting out, boring, in particular
completed by folding. This advantageously permits to provide a
static mixer particularly effective for particularly reduced
manufacturing costs.
[0034] Other aims and advantages of this invention will appear
during the following description, referring to embodiments that are
given only by way of an example, and non-restrictively.
[0035] The understanding of said description will be facilitated by
referring to the drawings attached hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a schematic view of an exhaust line comprising an
exhaust element according to the invention.
[0037] FIG. 2 is a schematic, partially cross-sectional,
longitudinal view of an exhaust element consisting of an exhaust
conduit and receiving, inside, a means for mixing (mixer) an
additive with exhaust gases.
[0038] FIG. 3 is a schematic detailed view of such a mixer.
[0039] FIGS. 4a and 4b are schematic detailed views representing,
respectively, each of the two modules constituting such a
mixer.
[0040] FIGS. 5a through 5d are schematic detailed views
corresponding to a first embodiment of the installation of such a
mixer inside an exhaust element shown in FIG. 2.
[0041] FIGS. 6a through 6c are schematic detailed views
corresponding to a second embodiment of the installation of such a
mixer inside an exhaust element shown in FIG. 2.
DETAILED DESCRIPTION OF THE DRAWINGS
[0042] The invention is related to the field of the automobile
industry and, in particular, that of manufacturing equipment
designed to ensure the exhausting of gases obtained from the
burning of a fuel inside a combustion engine 1a motor vehicle
includes.
[0043] Such equipment is in the form of an exhaust line 2,
connected to this engine 1, comprising a plurality of exhaust
elements (3; 4) following one another along this exhaust line
2.
[0044] In particular and as shown in FIG. 1, this exhaust line 2
can include at least one exhaust element 3 consisting of a device
for ensuring the physical and/or chemical treatment of gases
obtained from the burning of a fuel in the engine 1.
[0045] Such a treatment device 3 may consist of a particulate trap
31 (usually called FAP) placed downstream of the engine 1.
[0046] Such a treatment device 3 can also consist of a catalytic
converter 32, also placed downstream of the engine 1. According to
a first embodiment shown in FIG. 1 and corresponding to a standard
configuration of an exhaust line 2, said catalytic converter 32 can
be placed downstream of the abovementioned particulate trap 31.
However, and according to another embodiment that is not shown,
such a catalytic converter 32 can also be integrated into a more
complex exhaust element 3 (usually called cata-FAP) incorporating
such a catalytic converter 32 as well as a particulate trap 31 of
the abovementioned type.
[0047] In fact, such a catalytic converter 32, in particular and at
least partially, consists of a catalytic converter for the
treatment of nitrous oxides (NOx) contained in the exhaust
gases.
[0048] Such a catalytic converter 32 for treating nitrous oxides
may consist of a catalytic converter for the trapping of these
nitrous oxides (usually called NOx trap) or also of a catalytic
converter for the catalytic reduction of these nitrous oxides, for
example a three-way catalytic converter of the type TWC or also a
catalytic converter of the type SCR (Selective Catalytic
Reduction).
[0049] In the particular case of a catalytic converter 32 for
reducing nitrous oxides, this catalytic converter 32 includes,
inside, a means (in particular ceramic or analogous means) for the
treatment of exhaust gases, said treatment means being designed to
ensure the catalytic reduction of nitrous oxides contained in these
gases.
[0050] In this connection, it should be noted that the catalytic
reduction of nitrous oxides contained in exhaust gases is
facilitated when these gases contain a reducing agent.
[0051] The presence in these gases of such a reducing agent can be
ensured by introducing, inside the exhaust line 2 and upstream of
the catalytic converter 32, such a reducing agent or the precursor
of such a reducing agent which, inside the exhaust line 2 and
upstream of the treatment means, is transformed into such a
reducing agent.
[0052] To this end, the exhaust line 2 is complemented with a means
5 placed downstream of the particulate trap 31 and upstream of the
catalytic converter 32, and designed to introduce (in particular by
injection, more specifically after pulverization or vaporization)
into this exhaust line 2 an additive that should be added to the
exhaust gases for making a fluid to be treated by catalytic
reduction in said catalytic converter 32.
[0053] This introduced additive consists of a reducing agent or of
a precursor of such a reducing agent.
[0054] In fact, and according to a preferred embodiment, this
additive is based on urea and may consist of a solution (in
particular a water solution) having a small urea content, in
particular known by the name of AdBlue (precursor of a reducing
agent). This solution undergoes a chemical transformation
(thermolysis, hydrolysis) inside the exhaust line 2 so as to be at
least in the form of ammonia (NH3), constituting the reducing
agent, mixed with the exhaust gases, inside the fluid to be
treated.
[0055] It should also be noted that effectiveness of catalytic
reduction of nitrous oxides contained in exhaust gases increases
with the increase of homogeneity of the fluid to be treated by the
catalyst 32.
[0056] In order to homogenize this fluid, the exhaust line 2 also
includes a static means 6 for mixing the additive with the exhaust
gases, this means 6, in the remaining part of the description and
for convenience raisons, being referred to as mixer 6.
[0057] Such a mixer 6 is, in this case, designed for mixing exhaust
gases with the additive consisting, as the case may be, of the
reducing agent (in case of introduction of an additive consisting
of such a reducing agent or after transformation into a reducing
agent of a precursor--introduced in the line 2--of such a reducing
agent) and/or of the precursor of such a reducing agent (in case of
introduction of an additive consisting of such a reducing agent
precursor).
[0058] In fact, and as shown in the attached Figures, said mixer 6
is placed, along the exhaust line 2 and inside the latter 2,
between the means 5 for introducing the additive and the means for
treating said fluid.
[0059] In this connection, and according to a first embodiment, not
shown, such a mixer 6 can be placed inside an exhaust element 3
consisting of a device 3 for the physical and/or chemical treatment
of exhaust gases the line 2 for exhausting the gases includes.
[0060] Said treatment device 3 includes, inside, the means 6 for
mixing an additive with the exhaust gases as well as, downstream of
this mixer 6, a means for the physical and/or chemical treatment of
the mixed fluid.
[0061] Preferably, this device 3 for treating exhaust gases
consists, in this case, of a catalytic converter 32 for catalytic
reduction of nitrous oxides contained in exhaust gases or also of a
more complex treatment device 3 of the abovementioned type
(cata-FAP) comprising such a catalytic converter 32.
[0062] However, and according to a preferred embodiment of the
invention, the means 6 for mixing an additive with the exhaust
gases is mounted inside an exhaust element 4 consisting of an
exhaust conduit 41.
[0063] As shown in the attached Figures, such an exhaust element 4
preferably consists of an exhaust conduit 41 for connecting a
particulate trap 31 to a catalytic converter 32.
[0064] In fact, and as shown in FIGS. 5a through 5d and 6a through
6c, such a conduit 41 preferably consists of two portions (411;
412) of conduit 41, at least one 411 of which receives, inside,
said mixer 6. The latter 6 is, in this case, introduced into this
portion 411 of conduit 41, through its open end, and before
connecting (in particular complemented with an integral connection,
for example by welding) this portion 411 of conduit 41 to the other
portion 412 of this conduit 41.
[0065] Irrespective of the nature (treatment device 3 or conduit
41) and/or the geometry of such an exhaust element (3, 4), the
latter also includes, inside, a means 7 for receiving the mixer 6
inside this exhaust element (3, 4).
[0066] In fact, and as shown in FIGS. 5a through 5d and 6a through
6c, such a receiving means 7 preferably consists of a particular
structure of the exhaust element (3, 4), in particular made by
deformation of this exhaust element (3, 4), in particular of an
open end a portion 411 of a conduit 41 constituting such an exhaust
element 4 includes.
[0067] According to the invention, the means 6 for mixing the
additive with the exhaust gases consists of at least one helicoid
61.
[0068] Such a helicoid 61 is at least characterized by a pitch, by
a length, by a diameter, by a thickness, by a width, by an axis
along which it extends and by a direction of rotation.
[0069] In this connection, it should be noted that the width of
such a helicoid 61 can be constant, in the direction D of flow of
the fluid through the exhaust element (3, 4). However, good results
have been obtained for a helicoid 61 for which this width is
increasing or, preferably, decreasing, in the direction D of flow
of the fluid through the exhaust element (3, 4).
[0070] In fact, and according to another feature of such a helicoid
61, the latter has a width adapted to the structure of the exhaust
element (3, 4) receiving at least one such helicoid 61. Such an
embodiment advantageously permits to adjust the width of at least
one such helicoid 61 to such a structure (in particular to the
section of this exhaust element (3, 4), in particular in order to
occupy the entire internal volume of the latter (3, 4).
[0071] Also, and according to another feature, such a helicoid 61
has an axis extending in a direction forming a set angle .alpha.
with the direction D of flow of the fluid through this exhaust
element (3, 4).
[0072] In this connection, it should be noted that the direction of
extension of the axis of such a helicoid 61 forms with said
direction D of flow of the fluid through the exhaust element (3, 4)
an angle .alpha. between 0 and 30.degree..
[0073] According to a particular embodiment of the invention, not
shown, said mixer 6 may consist of a single helicoid 61 placed
inside an exhaust conduit 41 and the axis of which is at least
parallel, in particular coinciding, with the axis of such a conduit
41.
[0074] However, and according to a preferred embodiment of the
invention, this mixer 6 includes, in fact, a plurality of helicoids
61.
[0075] Such an embodiment advantageously permits to adapt the mixer
6 to the section of the exhaust element (3, 4) that it equips
and/or to improve the quality of the homogenization of the fluid at
the exit of the mixer 6.
[0076] By way of example, such a mixer 6 may include: [0077] two
helicoids 61 for an exhaust element (3, 4) having a substantially
rectangular cross-section; [0078] three helicoids 61 for an exhaust
element (3, 4) having a substantially triangular cross-section;
[0079] four helicoids 61 for an exhaust element (3, 4) having a
substantially square (FIG. 6c) or round (FIG. 5d)
cross-section.
[0080] Another feature of the invention consists in that these
helicoids 61 each have an axis, on the one hand, extending in a
direction forming a set angle .alpha.' with the direction of
extension of the axis of the other helicoid or helicoids 61 of the
mixer 6 and, on the other hand, extending in a direction forming a
set angle .alpha. with the direction D of flow of the fluid through
this exhaust element (3, 4).
[0081] In this connection, it should be noted that the direction of
extension of the axis of a helicoid 61 forms, in fact, with the
direction of extension of the axis of another helicoid or helicoids
61, an angle .alpha.' between 0 and 30.degree..
[0082] In a similar case, and as mentioned above, the direction of
extension of the axis of such a helicoid 61 can also form with the
direction D of flow of the fluid through the exhaust element (3, 4)
an angle .alpha. between 0 and 30.degree..
[0083] A particular embodiment (shown in the attached Figures)
consists in that the angles .alpha. and .alpha.' are null, so the
axis of a helicoid 61 is parallel to the direction of extension of
the axis of the other helicoid or helicoids 61 of the mixer 6 as
well as to the direction D of flow of the fluid through this
exhaust element (3, 4).
[0084] In such a case, the extension axes of helicoids 61 are
parallel between them.
[0085] However, and according to another configuration, not shown,
these helicoids 61 can be arranged so that their extension axes
diverge or, preferably, converge in the direction D of flow of the
fluid through the exhaust element (3, 4).
[0086] As mentioned above, these helicoids 61 have a width that is
constant, increasing or decreasing, and/or adapted to the structure
of the exhaust element (3, 4), in the direction D of flow of the
fluid through the exhaust element (3, 4).
[0087] This feature, combined with that of the direction of
extension (in particular in a convergent or divergent manner) of
the axes of these helicoids 61 advantageously permits to adjust
these helicoids 61 to the structure of the exhaust element (3, 4)
(in particular to the cross-section of the latter), in particular
in order to occupy the entire internal volume of this exhaust
element (3, 4).
[0088] According to an additional feature of the invention, the
axes of these helicoids 61 are arranged according to a matrix
(rectangular, triangular, square . . . ), in particular a regular
one, with respect to the geometry (respectively rectangular,
triangular, round or square . . . ) of the cross-section of this
exhaust element (3, 4). Such an embodiment advantageously permits
to optimize the positioning and the distribution of these helicoids
61 inside the exhaust element (3, 4), with respect to and depending
on the structure of the latter (3, 4).
[0089] As mentioned above, each helicoid 61 has a direction of
rotation.
[0090] In this connection, it should be noted that, according to an
additional feature of the invention, two immediately juxtaposed
helicoids 61, and even the entirety of helicoids 61 of the mixer 6,
can have the same direction of rotation.
[0091] Such an embodiment is particularly advantageous when the
fluid adopts a longitudinal turbulent movement (swirl) upstream of
the mixer 6.
[0092] However, and according to a preferred embodiment of the
invention (FIGS. 3, 5d, 6c), such immediately juxtaposed helicoids
61 preferably have a direction of rotation that is opposite
(counter revolving helicoids). Such an embodiment advantageously
permits to obtain a fluid to be treated that is optimally
mixed.
[0093] Another feature of the invention consists in that the mixer
6 according to the invention comprises a plurality of helicoids 61
and that these helicoids 61 are grouped together inside at least
one set (611; 612) comprising at least two helicoids 61.
[0094] In this connection, it should be noted that helicoids 61 of
the same set (611; 612) of helicoids 61 have, as the case may be, a
direction of rotation that is opposite (counter revolving
helicoids) or (preferably) identical (FIGS. 3, 4a, 4b, 5d, 6c).
[0095] A particular embodiment, not shown, can consist of a mixer 6
comprising a single set of at least two helicoids 61, in particular
adapted to an exhaust element 4 having a rectangular or oblong
cross-section.
[0096] However, and according to a preferred embodiment of the
invention, the mixer 6 includes, on the one hand, at least one set
611 (even a plurality of sets, preferably parallel) of at least two
(or more) helicoids 61 aligned in a first set direction and, on the
other hand, at least another set 612 (even a plurality of other
sets, preferably parallel) of at least two (or more) helicoids 61
aligned in a second set direction, making an angle (preferably a
right angle) with the first set direction.
[0097] In this connection, it should be noted that the number of
these sets (611; 612), the number of helicoids 61 constituting such
a set (611, 612) as well as the arrangement and the orientation of
these sets (611, 612) are determined depending on the geometry of
the exhaust element (3, 4) receiving the mixer 6, in particular in
order to optimize the filling of the surface offered by the
cross-section of the exhaust element (3, 4).
[0098] A preferred embodiment of the invention (shown in FIGS. 3
through 6c) consists in that the mixer 6 comprises two sets (611;
612) of helicoids 61, in particular perpendicular, each comprising
a pair of helicoids 61. In this embodiment, the two helicoids 61 of
the same set (611, 612) have the same direction of rotation,
whereas the two immediately juxtaposed helicoids 61 of two
different sets (611; 612) may have the same direction of rotation
but have preferably, as shown in FIGS. 3 through 6c, a direction of
rotation that is opposite.
[0099] Such a mixer 6 having four helicoids 61 can be placed inside
an exhaust element (3, 4), either consisting of a device 3 for
treating gases, as mentioned above, or consisting of an exhaust
conduit 4 made based on a traditional (and most commonly used)
design and which has a round cross-section (FIGS. 2 through
6c).
[0100] In the latter case, the axes of said four helicoids 61 are
preferably arranged according to a matrix that is square compared
to the round geometry of the cross-section of the exhaust element
41.
[0101] According to a first embodiment shown in FIGS. 5a through
5d, these four helicoids 61 are placed inside a portion 411 having
a round cross-section of said exhaust conduit 41.
[0102] However, and according to a preferred embodiment of the
invention shown in FIGS. 6a through 6c, said four helicoids 61 are
placed inside a specific portion 411' having a square cross-section
defined at the level of said exhaust conduit 41 having a round
cross-section. Such an embodiment advantageously permits to
increase the effectiveness of the mixer 6, diminishing the surface
of the cross-section of the conduit 41 slightly (and even in no
way) affected by the action of the helicoids 61, proportionally
with respect to a round cross-section.
[0103] In fact, this portion 411' having a square cross-section can
be defined by deformation of the exhaust conduit 41 having a round
cross-section, in particular by expansion.
[0104] According to another feature of the invention, these
helicoids 61 have a diameter between 25 and 40% (preferably in the
range of 35%) of the internal diameter (portion 411 having a round
cross-section of the conduit 4) or of the maximum cross-section
(portion 411' having a square cross-section of the conduit 4) of
the portion (411, 411') of exhaust conduit 4 receiving these
helicoids 61.
[0105] A preferred embodiment was described above regarding a mixer
6 comprising two sets (611, 612) each consisting of two helicoids
61. This invention is however in no way limited to such a
configuration.
[0106] Also, and according to another embodiment, not shown, said
mixer 6 can also include at least one set (611; 612) consisting of
more than two helicoids 61 (in particular 3, 4 or more) arranged in
alignment. Another embodiment can also consist of a mixer 6
comprising a plurality of sets comprising, for some at least, a
different number of helicoids 61.
[0107] Thus, one can conceive a mixer 6 comprising, on the one
hand, at least one set 611 (and even a plurality of sets,
preferably parallel) comprising 3, 4 or more helicoids 61 aligned
in a first set direction and, on the other hand, at least another
set 612 (and even a plurality of other sets, preferably parallel)
of at least two (or more) helicoids 61 aligned in a second set
direction, making an angle (preferably a right angle) with the
first set direction.
[0108] An additional feature consists in that these helicoids 61
have a length between 60 and 100 mm, preferably in the range of 80
mm, in particular 82 mm.
[0109] According to another feature of this invention, the static
means 6 for mixing the additive with the exhaust gases comprises at
least one module 62, each comprising, on the one hand, a plate
(621; 622) oriented parallel to the direction D of flow of the
fluid through the exhaust element and, on the other hand, at least
one helicoid 61 or a set (611; 612) of at least two helicoids 61
extending in the extension downstream of said plate (621; 622).
[0110] In this connection, it should be noted that such a plate
(621; 622) has two longitudinal sides and that, in particular, from
one of said longitudinal sides (in particular the downstream
longitudinal side) and in its extension extends at least one
helicoid 61 or extend the helicoids 61 of a set (611; 612) of
helicoids 61 a module 62 includes.
[0111] In fact, and according to a first embodiment, not shown,
such a mixer 6 can include a single module 62 comprising a plate
621 as well as a helicoid 61 or a set of at least two helicoids
611.
[0112] However, and according to a preferred embodiment, said mixer
6 comprises a plurality of modules 62, on the one hand, each
comprising a plate (621; 622) as well as a set (611; 612) of at
least two helicoids 61 and, on the other hand, assembled, two by
two, in particular perpendicularly, through assembling means 63 at
least one plate (621; 622) of at least one such module 62
includes.
[0113] In this connection, it should be noted that said assembling
means 63 consist, on the one hand, of an interlocking means 631,
which a plate 621 is provided with, and, on the other hand, by a
complementary interlocking means 632, which the other plate 622 is
provided with.
[0114] As shown in FIGS. 4a and 4b, such an interlocking means 631
consists of a notch made in the upstream portion of a plate 621 (in
particular at the level of the longitudinal side upstream of said
plate 621), whereas the complementary interlocking means 632
consists of another notch made correspondingly in the downstream
portion of the other plate 622 (in particular at the level of the
longitudinal side downstream of said plate 622).
[0115] As shown in FIGS. 3, 5d and 6c, such an assembling is made
so that the helicoid 61 of a set 611 of helicoids be, preferably,
inserted between two helicoids 61 of another set 612 of helicoids
61, yet being offset laterally with respect to the direction of
alignment of the two helicoids 61 of said other set 612.
[0116] Another feature consists in that a module 62 includes, at
the level of at least one of the lateral edges of a plate (621;
622) of said module 62, a wing (641; 642) located in the extension
of this plate (621; 622).
[0117] In the particular case of a mixer 6 comprising a single
module 62, the two lateral edges of such a plate 621 can be
prolonged by such a wing (641; 641') that extends in fact laterally
with respect to such a plate 621. These wings (641; 641')
advantageously constitute a means 8 for mounting the mixer 6 inside
the exhaust element (3, 4), in particular by being received by the
reception means 7 comprised by this exhaust element (3, 4)
includes
[0118] In case of a mixer 6 comprising a plurality of modules 62,
each of these modules 62 includes, at the level of at least one of
the lateral edges of a plate (621; 622) of said module 62, a wing
(641; 642) located in the extension of said plate (621; 622) and
oriented in the direction of another wing (642; 641) the plate
(622; 621) of another module 62 includes and which said wing (641;
642) can be made integral with, in particular by welding.
[0119] A preferred embodiment shown in FIGS. 3, 4A, 4b, 5d and 6c
consists in that the plates (621; 622) of each module 62 comprise,
at the level of their two lateral edges, a wing (641, 641'; 642,
642') located in the extension of such a plate (621; 622) and
oriented in the direction of another wing (642, 642'; 641, 641')
the other plate (622; 621) includes and which said blades (641,
641'; 642, 642') are or can be made integral with, in particular by
welding.
[0120] In this connection, it should be noted that said wings (641,
641'; 642, 642') advantageously constitute, in fact, a means 8 for
mounting the mixer 6 inside the exhaust element (3, 4), in
particular by being received by the receiving means 7 this exhaust
element (3, 4) includes.
[0121] Another advantageous feature of the invention consists in
that a module 62 as described above preferably consists of a single
part, in particular a metallic part, preferably made by cutting
out, boring, in particular complemented by folding.
[0122] The following are defined, in particular, at the level of
such a single part: [0123] a plate (621; 622); [0124] at least one
helicoid 61 or a set (611; 612) of at least two helicoids 61;
[0125] and, if such a module 62 includes an assembling means (63,
631, 632), at least one wing (641, 641'; 642, 642').
[0126] As mentioned above, the exhaust element 3 comprising a mixer
6 having the abovementioned features may consist of a device 3 for
the physical and/or chemical treatment of exhaust gases comprising,
inside, the means 6 for mixing an additive with the exhaust gases
as well as, downstream of this mixer 6, a means for the physical
and/or chemical treatment of this mixture.
[0127] Such a treatment device 3 may consist: [0128] either of a
catalytic converter 32 for the treatment of nitrous oxides (NOx)
contained in the exhaust gases, in particular for catalytic
reduction of said nitrous oxides (NOx), for example a three-way
catalytic converter of the type TWC or also a catalytic converter
of the type SCR (Selective Catalytic Reduction); [0129] or of a
more complex exhaust element 3 (usually called cata-FAP)
incorporating such a catalytic converter 32 as well as a
particulate trap 31 of the abovementioned type.
[0130] However, and according to a preferred embodiment, the
exhaust element 4 according to the invention preferably consists of
an exhaust conduit 41 comprising, inside, the means 6 for mixing an
additive with the exhaust gases having the abovementioned
characteristics.
[0131] Finally, the invention also relates to a line 2 for
exhausting the gases for motor vehicles with a combustion engine 1
and comprising, according to the direction of the flowing of the
gases within said exhaust line 2, on the one hand, a means 5 for
introducing into this exhaust line 2 an additive to be added to the
exhaust gases, on the other hand, a static means 6 for mixing this
additive with the exhaust gases and, on yet another hand, a means
for the physical and/or chemical treatment of this mixture.
[0132] According to the invention, this exhaust line 2 comprises an
exhaust element (3, 4) having the abovementioned features, and
comprising said means 6 for mixing the additive with the exhaust
gases. Said mixer 6 is interposed between the means 5 for
introducing the additive into the line 2 and the means for treating
the mixture (in particular comprised, inside, by a device 3 for the
physical and/or chemical treatment of this mixture in case of an
exhaust element 3 consisting of such a device 3).
[0133] This invention will find an application in the field of
manufacturing equipment for exhausting the gases emitted by the
engine 1 of a motor vehicle and obtained from the burning of a
fuel, in particular of a fuel of the diesel type, inside such an
engine 1.
Exemplary Embodiment
[0134] Output of the engine at full load: 600 kg/h at 600.degree.
C.
[0135] Mixer 6: [0136] two pairs of helicoids (611; 612); [0137]
two helicoids of the same pair with the same direction of rotation;
[0138] two helicoids of two different pairs with an opposite
direction of rotation (counter revolving helicoids); [0139] pitch
and length of helicoids: 82 mm [0140] diameter of helicoids: 21 mm
[0141] exhaust element: a conduit having an internal diameter of 60
mm [0142] back pressure generated downstream of the mixer: 33
mbar
* * * * *