Improved mixer for ATS system
Patent Information
- Application Number
- PCT/IB2026/051707
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-26
- Filing Date
- 2026-02-23
- Publication Date
- 2026-09-03
Smart Images
Figure IB2026051707_03092026_PF_FP_ABST
Abstract
Description
[0001] "IMPROVED MIXER FOR ATS SYSTEM"
[0002] Cross-Reference to Related Applications This Patent Application claims priority from Italian Patent Application No . 102025000003780 filed on February 26, 2025, the entire disclosure of which is incorporated herein by reference .
[0003] Technical Field
[0004] The present invention concerns a mixer for an after-treatment system.
[0005] The present invention finds its preferred, although not exclusive, application in vehicular engine systems in vehicle . Reference will be made to this application by way of example below.
[0006] Background of the Invention
[0007] Vehicles, in particular heavy and work vehicles, need to treat exhaust gases coming from the engine before their emission in the environment in order to decrease level of pollute elements such as nitrogen oxide or particulate .
[0008] In order to achieve such treatment, it is known to use systems known as After Treatment Systems (ATS) comprising a series of elements such as Diesel Oxidation Catalysts (DOC) , Urea (i . e . AdBlue ® urea solution) Inj ection Module, Diesel Particulate Filters (DPF) or Selective Catalytic Reduction (SCR) ; this latter may comprise more intermediate elements such as SCRoF (Selective Catalytic Reduction on Filter) and SCR-CUC (Clean Up Catalyst) .
[0009] In such systems it is essential to provide a correct mixing between urea (inj ected through dosing modules) and exhaust gases flow flowing out from DOC module before its passage into SCR in order to generate a gas mixture whichallows the correct execution of reduction chemical reactions of the nitrogen oxide contained in exhaust gases .
[0010] To obtain the above-described mixing of urea and exhaust gases it is known to provide after treatment systems which has a great linear extension in which urea inj ection module comprises an inclined dosing module which inj ect urea solution in a long mixing conduit . However, such long conduit increases the encumbrance of ATS in the vehicle .
[0011] To solve the aforementioned problem, it is possible inj ect urea at higher pressure into the exhaust gas flow; this allows to use shorter mixing conduits, however high-pressure urea dosing modules are more expensive and need peculiar urea feeding circuits which are more expensive and prone to breakage than "standard" dosing module (at lower pressures) and related circuit .
[0012] A correct mixing of urea solution into exhaust gases is essential, otherwise urea could crystallize on inner walls of conduit of the ATS; this drawback generates from the fact that the inj ected urea is at environment temperature, i . e . about 25°C, while the exhaust gases are at a temperature of at least 300 °C .
[0013] In view of the above, it is essential to avoid an excessive loss of temperature in the mixing module because, first, the efficiency of chemical reduction reactions is decreased and further because the possibility of formation of ammonia crystal is reduced at high temperature . Again, the presence of a long linear mixing conduit introduces a significant drop in temperature of exhaust gases .
[0014] Moreover, a long mixing conduit as the above described one increases the pressure drop between inlet and outlet of the ATS while it is necessary to have a minimal pressuredrop OF ATS to improve engine efficiency.
[0015] Therefore, the need is felt to provide an ATS which allows a correct mixing of urea solution with the exhaust gas flow, which is compact, which does not rise manufacturing costs and which does not increase the standard pressure drop between inlet and outlet of the ATS .
[0016] An aim of the present invention is to satisfy at least one of the above-mentioned needs .
[0017] Summary of the Invention
[0018] The aforementioned aim is reached by a mixer and an ATS system as claimed in the appended set of claims that are integral part of the present description.
[0019] Brief Description of Drawings
[0020] For a better understanding of the present invention, a preferred embodiment is described in the following, by way of a non-limiting example, with reference to the attached drawings wherein:
[0021] • Figure 1 is schematic sectional view of a mixer within an after-treatment system according to the invention;
[0022] • Figure 2 is a perspective view of a mixer according to the invention in a first operative condition;
[0023] • Figure 3 is a schematic sectional view of the mixer within the after-treatment system in the first operative condition of Figure 2 ;
[0024] • Figure 4 is a perspective view of a mixer according to the invention in a second operative condition;
[0025] • Figure 5 is a schematic sectional view of the mixer within the after-treatment system in the second operative condition of Figure 4 ;
[0026] • Figures 6 and 7 are schematic sectional views of an alternative embodiment corresponding to the mixer offigures 3 and 5;
[0027] • Figure 8 is a perspective view of a further alternative embodiment of the mixer according to the invention; and
[0028] • Figures 9 and 10 are front schematic views of a first and a second operative condition of the mixer of figure 8 with parts removed for sake of clarity.
[0029] Detailed Description of the Invention Figures 1 and 2 show a mixer 1 for an After Treatment Systems (ATS) 100 that can be used in an engine system of a vehicle such as a heavy vehicle . Although not illustrated in detail for the sake of brevity, the mixer 1 is housed in a space 101 defined by the ATS system 100.
[0030] In particular, the ATS system 100 comprises a plurality of modules housed upstream and downstream to the mixer 1 and urea inj ector means 102 configured to inj ect urea in space 101 .
[0031] In the disclosed embodiment, the urea inj ector means provide a urea flow U coaxially with a longitudinal axis A of the mixer, while an inlet flow Fin of exhaust gas to be mixed with urea flow U is inclined, in particular perpendicular, with respect to the longitudinal axis A.
[0032] The mixer 1 preferably comprises an internal tubular element 3 and an external tubular element 2 configured to house at least part of the internal tubular element 3.
[0033] The internal and external tubular elements 3, 2 have an axisymmetric shape with respect to the longitudinal axis A and are both advantageously cylindrical in shape .
[0034] Preferably, both the external tubular element 2 and the internal tubular element 3 are fixedly carried by different portions of the ATS system 100.In detail, the internal tubular element 3 has a diameter smaller than the diameter of the external tubular element 2 so that it is housed radially inside it and radially separated by a space 4 .
[0035] From a longitudinal point of view, both external and internal tubular elements 2, 3 comprises a first and a second ends 2' , 3' , 2' ’ , 3' ’ along longitudinal axis A.
[0036] In detail, the internal tubular element 3 extends longer along longitudinal axis A with respect to external tubular element 3, in particular at least one between the first and second ends 2’ , 2’ ’ 3' , 3’ ’ of one between internal and external tubular elements 2, 3 extends over the other ones .
[0037] In the disclosed embodiment, the first ends 2’ , 3’ are substantially coincident along longitudinal axis A, while second end 3’ ’ of internal tubular element 3 extends over the second end 2’ ’ of the external tubular element 2.
[0038] The mixer 1 further comprising a swirling module 5 configured to impart a swirl on inlet exhaust flow Fin before entering in the internal tubular element 3.
[0039] In particular, the first end 3’ of the internal tubular element 3 carries the swirling module 5 that extends radially over the external tubular element 2 and is axially coupled to the latter .
[0040] In detail, the swirling module 5 is placed adj acent to urea inj ection means 102.
[0041] According to the above, the space 4 is radially delimited by the internal and external tubular elements 3, 2, axially delimited from one side by swirling module 5 and opened on the opposite side .
[0042] In detail, the external tubular element 2 comprises, at the first end 2’ , at least one opening 6 configured to allowfluid communication between space 101 and the space 4.
[0043] The inlet flow Fin of exhaust gas passing through mixer 1 is then divided into a first portion F' passing through swirling module 5 within the internal tubular element 2 and a second portion F' ’ passing through the at least one opening 6 in the space 4 .
[0044] As better shown in figures 2 and 4, the external tubular element 2 comprises a plurality of openings 6 that extends circumferentially along longitudinal axis A and are passing through the external tubular element 2 radially to this latter .
[0045] In particular, openings 6 have all the same shape, in the disclosed embodiment substantially quadrangular and are provided only in the first end 2’ .
[0046] Within the space 4, the mixer 1 comprises fins 7 configured to increase heat exchange between the fluid passing through space 4 and the internal tubular element 3. Accordingly, such fins 7 are preferably carried by the internal tubular element 3.
[0047] More preferably, and as shown in the attached figures, the fins 7 extends along longitudinal axis A and are preferably realized as parallel one with respect to the other more preferably one having the same shape of the other and furthermore preferably equally in circumferential direction about longitudinal axis A.
[0048] As further disclosed and better shown in figure 1, the fins 7 are provided between the at least one opening 6 and the end of the external tubular element 2.
[0049] Referring back to swirling module 5, it comprises a first wall 8 and a second wall 9 spaced along the longitudinal axis A and a plurality of blades 10 interposed between thefirst and second wall 9 to impart a swirling motion to the first portion F' of inlet flow Fin before entering within internal tubular element 2 .
[0050] In particular, the first and second walls 8, 9 have preferably an annular shape, thereby allowing, respectively, the inj ection of urea flow U from urea inj ector 102 on one side and, on the other one, the passage of first portion F' of inlet flow Fin within the internal tubular element 2' .
[0051] Blades 10 can be of any suitable shape and are preferably equally dimensioned one with respect to the other . More preferably, they are equally spaced circumferentially about longitudinal axis A. In particular, blades 10 are shaped in order to provide a swirling on the first portion F' of exhaust gas while entering in internal tubular element 2’ . To this aim, preferably, they have a wing profile .
[0052] Preferably, the blades 10 are carried by at least one between the first and second wall 8, 9.
[0053] In all embodiments, at least some among blades 10 are movable within a first operative position when the flow-rate of first portion F' is at a minimum value and a second position when the flow-rate of first portion F' ’ is at a maximum value or an intermediate position between these latter .
[0054] In the embodiments shown in figures 1 to 7, at least some among blades 10 are movable along longitudinal axis A in order assume a position between first operative position in which they are interposed through the first portion F' of exhaust gases thereby imposing swirl and a second operative position in which they are not interposed through the above or any suitable position between such first and second operative positions .In particular the passage between the aforementioned condition can be passively controlled or actively controlled in function of the flow-rate of inlet flow F' .
[0055] In particular, both first and second wall 8, 9 comprises blades 10 that are fixedly carried to the respective wall 8, 9; one between such walls 8, 9 is movable thereby carrying the blades 10 between the first and the second operative positions .
[0056] In detail, the second wall 9 is movable between the first operative condition, wherein the blades 10 are at a minimum distance and - preferably- contact the first wall 8 and the second operative condition, wherein the blades are at a maximum distance with respect to the second wall 8.
[0057] Preferably, in circumferential direction, blades are alternated one with respect of the other along a predetermined pattern, i . e . they are alternated as carried by the first either by the second walls 8, 9.
[0058] In the disclosed embodiment, each blade 10 carried by the second wall 9 is comprised between a blade 10 carried by the first wall 8, i . e . blades 10 are alternated on a single base manner .
[0059] In embodiment of figures 1 to 5, the second wall 9 is connected to a fixed portion 2a of the internal tubular element 2 by resistance means 11, such as elastic means 11. Such fixed portion 2a is placed opposite with respect to the second wall 9 to the first wall 8.
[0060] In detail, elastic means 11 comprises helicoidal spring housed in a related housing of the fixed portion 2a and configured to cooperate by contact with corresponding pins 12 connected to the second wall 9.
[0061] Elastic means 11 are designed to exert a predeterminedforce against the movement of the second wall 9 corresponding to a predetermined flow-rate value of the first portion F' of exhaust gas . Due to the shape of the blades 10, if the flow-rate increases over such predetermine value, the elastic means 11 tends to compact, thereby allowing movement of the second wall 9 distancing from the first wall 8 and thereby removing blades 10 from their initial portion.
[0062] The embodiment of figures 6 and 7 is similar but further comprises actuator means 13 configured to substitute elastic means 11 or to act- as per the disclosed embodiment, in addition to these latter .
[0063] In detail, in the disclosed embodiment, the actuator means 13 comprises an electric motor mechanically connected to the second wall 9 to act move this latter between the first and second operative positions .
[0064] Clearly, in such embodiment, the ATS system 100 comprises an electronic control unit (not shown and that can be the electronic control unit of the engine system or of the vehicle) comprising elaboration means configured to elaborate a value of flow-rate of the inlet flow Fin, associate such flow-rate to a position of the movable blades 10 and control consequently the position of these latter in function to the associate position.
[0065] In particular, the ATS system 100 may comprise sensor means configured to retrieve a physical quantity indicative of the flow-rate of the inlet flow Fin. Alternatively, or in combination, the electronic unit may receive operational data of the engine system and estimate the flow rate on the base of these latter .
[0066] Figures 8 to 10 show another embodiment of the mixer 1 in which the first and second operative positions correspondsto different inclinations about longitudinal axis A of the blades 10 (rather than a movement along longitudinal axis A as per embodiments of figures 1 to 7 ) .
[0067] In such embodiment, the blades 10 are each carried in a movable manner between the first and second walls 8, 9. In detail, each blade 10 is further connected by a mechanism 20 to one between the first and second walls 8, 9. In the disclosed embodiment, the first wall 8.
[0068] In particular, mechanism 20 comprises an arm 21 that is carried at one extremity at the first wall 8 and to the other extremity to a respective blade 10. The blade 10 is connected by a first hinge connection 22 to the extremity of the arm 21 and by a second hinge connection 23 to the second wall 9.
[0069] The first wall 8 is configured to rotate, under action of actuator means 13, such as the electric motor described for the embodiments of figures 6 and 7, about axis A. Such rotation causes the motion of blades between a first operative position ( figure 9) corresponding to a maximum swirl, useful for a minimum flow-rate of first portion F' of inlet flow and a second operative position ( figure 10) corresponding to a minimum swirl, useful for maximum flowrate of first portion F' of inlet flow or an intermediate position between the aforementioned first and second operative positions .
[0070] The operation of the above-described embodiment of the mixer 1 according to the invention is as follows .
[0071] In all embodiments, the inlet exhaust gas flow Fin is divided into a first and a second portions F' , F' ' . The first portion F' passes through swirling module 5 that imparts a swirling movement before entering in the internal tubular element 2 in which the swirled exhaust gas is mixed withurea flow U, thereby providing a good mixing between the aforementioned two flows . The second portion F' ' passing directly in space 4 heat the internal tubular element 2, thereby avoiding formation of ammonia crystals . Once come out, the exist flow Fo is the sum of the first portion F' and the second portion F' ’ together with urea flow. The exit flow Fo is furthermore mixed due such joining of the preceding first and second portions F' .
[0072] In particular in function of the flow-rate of the exhaust inlet flow F' , the swirling module 5 at least some among its blades 10 passes between the first and second operative positions thereby providing less swirl - if the flow-rate is high and sufficient to allow mixing thereby reducing pressure drops - or higher swirl - if the flow-rate is low and insufficient to allow mixing and further swirling would not increase excessively pressure drops .
[0073] In the embodiment of figures 1 to 5 the passage is automatically regulated to due preload of the elastic means 11 that compress under the force of first portion F' acting on blades 10 that automatically adjust their position along the longitudinal axis A.
[0074] In the embodiment of figures 6 and 7, electronic control unit would control, based on a proper evaluation via sensor means or by interpolating data related to the engine system, an actuator that moves the blades 10 between the first and the second positions .
[0075] Similarly happens in the embodiment of figures 8 to 10, although the movement of blades is controlled by rotating the first wall 8. Such rotation would move arms 21 that make rotating about hinges 22 and 23 the blades between the first and second operative positions .In view of the above, when it is present an active actuator, the proposed invention further relates to a control method for a mixer as disclosed comprising the following steps :
[0076] i) Elaborating the flow-rate of the exhaust inlet flow (Fin) entering in said mixer ( 1 ) ;
[0077] ii) Associate the flow-rate at step (i) with a position of blades ( 10) ;
[0078] iii) Control the actuator means ( 13) to position blades ( 10) in the position associated at step ii) .
[0079] In particular, the elaboration at step i) is performed on the base of acquired data such as :
[0080] a) data from sensor means configured to retrieve a physical value indicative of the flow-rate of exhaust inlet flow (Fin) ; and / or
[0081] b) data related to the operation of the engine system.
[0082] The aforementioned steps can be performed by the electronic control unit of the ATS system, or of the engine system or of the vehicle .
[0083] The advantages of a mixer for an ATS system according to the invention are clear from the foregoing.
[0084] The mixer 1 allows high mixing indices for the urea solution in a compact space .
[0085] In particular, use of two different inlet mixing portions, one of which swirled, allows adequate mixing of the urea flow while preventing high pressure drops .
[0086] The use of two cylindrical tubular elements makes it possible to use particularly inexpensive and robust elements .In particular, the use of a swirling module in which blade can move or can be moved in function of the flow-rate further allows to reduce pressure drops while maintaining a good mixing level .
[0087] The passive control of the blade position is in particular advantageous while cheap; conversely, the proposed active control system allows a control according that optimizes the mixing in function of the needs of the engine system.
[0088] Moreover, the different proposed geometries and movements of blades provide a very versatile system that can be used in different mixer according to the pressure of the exhaust gases and in function of the spaces at disposal .
[0089] Lastly, it is clear that modifications and variations may be made to the mixer for an ATS system according to the present invention, without however departing from the scope of protection defined by the claims .
[0090] For example, the number and shape of the openings may vary depending on the size of the ATS system, as well as the shape of the blades or their number .
[0091] As demonstrated in the description, movements of the blades may be different and can be controlled or actively actuated in different manners .
[0092] For instance, the blades can have a combined longitudinal and rotational movement by providing a combination of the proposed embodiments of figures 6, 7 and 8 to 10.
Claims
CLAIMS1 . - A mixer ( 1 ) for an exhaust gas after-treatment system ( 100 ) , ATS , said ATS system ( 100 ) defining a space ( 101 ) for housing said mixer ( 1 ) and allowing passage of a exhaust flow and comprising an inj ector ( 102 ) for inj ecting an urea solution within said mixer ( 1 ) ,said mixer ( 1 ) comprising an internal tubular element ( 3 ) and an external tubular element ( 2 ) extending along a longitudinal axis (A) , said external tubular element ( 2 ) radially housing said internal tubular element ( 3 ) , wherein said external tubular element ( 2 ) is provided with at least one opening ( 6 ) and said mixer ( 1 ) is provided with a swirling module ( 5 ) ,a first portion ( F' ) of an exhaust gas inlet flow ( Fin) passing through said swirling module ( 5 ) within said internal tubular element ( 3 ) , said swirling module ( 5 ) comprising a plurality of blades ( 10 ) configured to impart a swirling motion to said first portion ( F' ' ) ,a second portion ( F' ' ) passing through said at least one opening ( 6 ) in a space ( 4 ) def ined between said internal and external tubular elements ( 2 , 3 ) ,wherein said blades ( 10 ) are movable between a first and a second operative positions in functions of the flowrate value of said exhaust gas inlet flow ( Fin) .2 . - Mixer according to claim 1 , wherein said blades ( 10 ) moved longitudinally along said longitudinal axis (A) .3 . - Mixer according to claim 1 or 2 , wherein said blades ( 10 ) rotates about axis parallel to said longitudinal axis (A) .4 . - Mixer according to any of the preceding claims , wherein the movement of said blades ( 10 ) is actively controlled by actuator means ( 13 ) .5 . - Mixer according to claim 4 , wherein said actuator means ( 13 ) comprises an electric motor controlled by an electronic control unit .6 . - Mixer according to any of claims 1 to 3 , wherein said blades ( 10 ) moves passively against a resistant force provided by resistance means ( 11 ) .7 . - Mixer according to claim 6 , wherein said resistance means ( 11 ) comprises elastic means operatively interposed between said blades ( 10 ) and a related support portion, said elastic means being designed to move i f the load acting on said blades ( 10 ) is greater than a preset value .8 . - Mixer according to any of the preceding claims , wherein said internal and external tubular elements ( 2 , 3 ) being provided with a first and a second portion ( 2 ' , 2 ' ’ , 3 ' , 3 ' ’ ) along said longitudinal axis (A) ,a first portion ( 3 ' ) of said internal tubular element ( 3 ' ) extending longitudinally more than a first portion ( 2 ' ) of said external tubular element ( 2 ) and carrying said swirling module ( 5 ) , said space ( 4 ) being axially delimited by one said by said swirling module ( 5 ) ,said first portion ( 2 ' ) of said external tubular element ( 2 ) defining said opening ( 6 ) .9 . - Mixer according to claim 8 , wherein said mixer ( 1 ) comprises a plurality of openings ( 6 ) reali zed circumferentially about said longitudinal axis (A) .10 . - Mixer according to any of the preceding claims , wherein said swirling module ( 5 ) comprises a first wall ( 8 ) and a second wall ( 9 ) , at least one between said first andsecond wall ( 8 , 9 ) being carried by said internal tubular element ( 3 ) .11 . - Mixer according to claim 10 , wherein said blades ( 10 ) are in part carried by said f irst wall ( 8 ) and in part carried by said second wall ( 9 ) , said second wall ( 9 ) moving along said longitudinal axis (A) thereby varying the position of its carried blades ( 10 ) .12 . - Mixer according to claim 11 , comprising elastic means ( 11 ) operationally interposed between said second wall ( 9 ) and a portion ( 2a ) fixedly carried by said internal tubular element ( 2 ) .13 . - Mixer according to claim 11 or 12 , comprising an actuator moving said second wall ( 9 ) .14 . - Mixer according to claim 10 , wherein said blades ( 10 ) are carried in a movable manner by at least one between said first and second walls ( 8 , 9 ) .15 . - Mixer according to claim 14 , wherein one between said first and second walls ( 8 , 9 ) being controlled to move about said longitudinal axis (A) , said swirling module ( 5 ) comprising a mechanism ( 20 ) connecting said blades to said one between said first and second walls ( 8 , 9 ) .16 . - ATS system ( 100 ) defining a space ( 101 ) and comprising an inj ector ( 102 ) for inj ecting an urea solution within said space ( 101 ) and a mixer ( 1 ) housed within said space ( 101 ) for mixing said urea solution together with an exhaust flow, said mixer ( 100 ) being according to any of the preceding claims .17 . - ATS system according to claim 16 , when said mixer depends on any claim depending on claim 4 or 5 , further comprising an electronic control unit , said electronic control unit comprising elaboration means conf igured tocontrol said actuator means ( 13) on the base of an elaboration of a flow-rate of said exhaust flow.
18. Control method for a mixer in an ATS system according to claim 17, said method comprising the following steps :i) Elaborating the flow-rate of the exhaust inlet flow (Fin) entering in said mixer ( 1 ) ;ii) Associate the flow-rate at step (i) with a position of blades ( 10) ;iii) Control the actuator means ( 13) to position blades ( 10) in the position associated at step ii) .
19. Method according to claim 18, wherein the elaboration at step i ) is performed on the base of acquired data, such data comprising:a) data from sensor means configured to retrieve a physical value indicative of the flow-rate of exhaust inlet flow (Fin) ; and / orb) data related to the operation of an engine system.