• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:

    公开号:SE1251489A1
    申请号:SE1251489
    申请日:2012-12-21
    公开日:2014-06-22
    发明作者:Fredrik Holmberg；Eric Furbo；Morgan Colling；Niklas Nordin；Hans Göransson；Henrik Birgersson；Tommy Erikssson
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    the conversion in the SCR catalyst. The ammonia accumulates in the catalyst by being adsorbed on active sites in the catalyst and NOX present in the exhaust gases is converted to nitrogen gas and water when it is brought into contact with the accumulated ammonia on the active sites in the catalyst.
    When urea is used as a reducing agent, it is injected into the exhaust line in the form of a liquid urea solution by means of an injection means. The injection means comprises a nozzle via which the urea solution under pressure is injected into the exhaust line in atomized form as a spray. During large parts of a diesel engine's operating condition, the exhaust gases have a sufficiently high temperature to be able to evaporate the urea solution so that ammonia is formed. However, it is difficult to avoid that part of the added urea solution comes into contact with and adheres to the inner wall surface of the exhaust line in an undisturbed state. When an internal combustion engine is operated in a uniform manner over a period of time, i.e. under a stationary operating condition, no appreciable variations of the exhaust gas flow occur and the urea solution injected into the exhaust gases will therefore hit substantially the same area of the exhaust line during this entire period. Under the action of the relatively cool urea solution, the temperature can be lowered locally in this area of the exhaust line to a temperature lower than 100 ° C, which in turn can lead to the formation of a film of urea solution in this area which is then drawn with of the exhaust gas flow. After this film has been moved a certain distance in the exhaust line, the water in the urea solution will boil away under the action of the hot exhaust gases.
    What remains is solid urea which is slowly evaporated by the heat in the exhaust line. If the supply of solid urea is greater than the evaporation, a solid urea accumulates in the exhaust line. If the layer of urea becomes sufficiently thick, the urea and its decomposition products will react with each other to form primitive polymers on urea base, so-called urea lumps. Such lumps of urea can eventually block an exhaust line.
    OBJECT OF THE INVENTION The object of the present invention is to provide an arrangement of the type initially stated which creates improved possibilities to ensure a good evaporation of the injected reducing agent.
    SUMMARY OF THE INVENTION According to the present invention, said object is achieved by means of an arrangement having the features defined in claim 1.
    The arrangement according to the invention comprises: - a mixing chamber intended to be flowed through by exhaust gases, the mixing chamber being delimited in radial direction outwards by a first tubular wall of metal, - an injection means for injecting the liquid medium as a spray into the mixing chamber, and - a exhaust duct adjacent to the mixing chamber, which is intended to flow through exhaust gases and extends along the outside of the first tubular wall, the exhaust duct being delimited from the mixing chamber by the first tubular wall and delimited in radial direction outwards by a second tubular wall , which is designed to direct the exhaust gases flowing through the exhaust duct to pass on the outside of the part of the first tubular wall which is intended to be hit by said spray of liquid medium from the injection means.
    The part of the first tubular wall which is hit by the spray from the injection means will thus be heated from its rear side by the exhaust gases flowing through said exhaust duct.
    According to the invention, a throttle is provided in the portion of the exhaust duct located on the outside of said wall portion of the first tubular wall to cause in this exhaust duct portion an acceleration of the exhaust gases flowing through the exhaust duct so that they flow at increased speed over the outside of this wall section. The heat transfer rate with respect to the heat transfer from a flowing gas to a surface increases with increasing flow rate of the gas. By causing the exhaust gases in the exhaust duct to flow over the wall part in question at an increased speed, an increased heat transfer from the exhaust gases to this wall part is thus achieved, which contributes to an efficient heating of the wall part. This makes it possible to effectively counteract the cooling caused by the injected medium hitting said wall part. The increased heat transfer from the exhaust gases to the wall part in question also contributes to an increased evaporation of the injected medium which hits this wall part. The solution according to the invention does not require the use of any heat flanges or other heat transfer means and is thereby extremely simple and advantageous.
    According to an embodiment of the invention, the first tubular wall has a varying wall thickness seen in the longitudinal direction of the mixing chamber, said wall part having a wall thickness which is greater than the wall thickness of the parts of the first tubular wall adjacent to this wall part.
    Due to the increased wall thickness of the part of the first tubular wall which is hit by the spray from the injection means, this wall part becomes capable of absorbing and storing a larger amount of heat from the passing exhaust gases compared with the other thinner wall parts. In this way, the thickened wall part is better able to counteract the cooling caused by the injected medium hitting this wall part. The stored heat also contributes to an increased evaporation of the injected medium that hits the current wall part. Due to its increased wall thickness, the wall part in question also has a better thermal conductivity, which leads to the cooling effect caused by the injected medium hitting the wall part being spread over a larger area. This spreading of the cooling action of the injected medium leads to a reduced cooling in the area affected by the spray from the injection means.
    Other advantageous features of the arrangement according to the invention appear from the dependent claims and the following description.
    BRIEF DESCRIPTION OF THE DRAWING The invention will be described in more detail below with the aid of exemplary embodiments, with reference to the accompanying drawing.
    It is shown in: Fig. 1 a schematic longitudinal section through an arrangement according to an embodiment of the present invention, and Fig. 2 a section along the line II-II in Fig. 1.
    DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Figs. 1-2 illustrate an arrangement 1 according to an embodiment of the present invention for introducing a liquid medium into exhaust gases from an internal combustion engine. The arrangement may, for example, be arranged in an exhaust line upstream of an SCR catalyst for introducing a liquid reducing agent in the form of urea or ammonia into the exhaust line upstream of the SCR catalyst, or be arranged in an exhaust gas aftertreatment device for introducing a reductive liquid. in the form of urea or ammonia upstream of an SCR catalyst included in the exhaust aftertreatment device.
    The arrangement 1 comprises a mixing chamber 2 which is intended to receive exhaust gases from an internal combustion engine and direct these exhaust gases further in the direction of an exhaust after-treatment unit, for example in the form of an SCR catalyst. The mixing chamber 2 is thus intended to be permeated by exhaust gases. The mixing chamber 2 has an upstream end 4 and a downstream end 5. The mixing chamber 2 is delimited in radial direction outwards by a first tubular wall 6 of metal, which extends between the upstream end 4 of the mixing chamber and the downstream end 5. The mixing chamber 2 has an inlet 7 for receiving exhaust gases at its upstream end and an outlet 8 for discharging exhaust gases at its downstream end. The inlet 7 is suitably annular and arranged to extend around the central axis 9 of the mixing chamber 9. The mixing chamber 2 suitably has a circular cross-sectional shape, as illustrated in Fig. 2.
    An injector 10 for injecting the liquid medium is arranged in the center of the upstream end 4 of the mixing chamber for injecting the liquid medium in the direction of the downstream end 5 of the mixing chamber. The injector 10, which may for example comprise an injector nozzle, is arranged under pressure, inject the liquid medium into the mixing chamber 2 in atomized form as a spray 11.
    The arrangement 1 comprises an exhaust duct 12 adjacent to the mixing chamber 2, which is intended to be permeated by exhaust gases and extends along the outside of the first tubular wall 6. The exhaust duct 12 surrounds the mixing chamber 2 and is concentric with this, as illustrated in Fig. 2. The exhaust duct 12 and the mixing chamber 2 are delimited from each other by the first tubular wall 6. The exhaust duct 12 is delimited in radial direction inwards by the first tubular wall 6 and in radial direction outwards by a second tubular wall 13, which is designed to direct the exhaust gases flowing through the exhaust duct 12 to pass on the outside of the part 6a of the first tubular wall which is intended to be hit by said spray 11 of liquid medium from the injection means 10.
    A choke 14 is provided in the portion 12a of the exhaust duct located on the outside of said wall portion 6a to cause in this exhaust duct portion 12a an acceleration of the exhaust gases flowing through the exhaust duct 12 so that they flow at increased speed over the outside of this wall portion 6a. At the throttle 14, the exhaust duct 12 has a cross-sectional area which is smaller than the cross-sectional area of the upstream throttle portion of the exhaust duct.
    In the illustrated example, the exhaust duct 12 is arranged downstream of the mixing chamber 2 and connected to the mixing chamber 2 via a flow reversing means 15, which is arranged to reverse the flow direction of the exhaust gases flowing out of the mixing chamber 2 so that they are caused to flow through the exhaust. the gas duct 12 in a flow direction opposite to the flow direction of the exhaust gases in the mixing chamber 2. In the illustrated embodiment, the flow reversing means 15 is arranged opposite the outlet 8 of the mixing chamber and provided with a central portion 15a and an annular edge portion 15b surrounding the center portion. The side of said middle portion 15a facing the mixing chamber 2 is suitably convex in shape, as illustrated in Fig. 1. The side of said edge portion 15b facing the mixing chamber 2 forms a guide surface 16 which is rounded to guide the exhaust gases flowing towards the flow reversing means 15. in a flow directed towards the annular inlet 17 of the exhaust duct while reversing the flow direction of these exhaust gases.
    In the illustrated embodiment, the first tubular wall 6 has a varying wall thickness seen in the longitudinal direction of the mixing chamber, the part 6a of the first tubular wall which is intended to be hit by said spray 11 of liquid medium from the injection means 10 having a wall thickness which is greater than the wall thickness of the parts 6b of the first tubular wall adjacent to this wall part 6a.
    In its thickest portion, the thickened wall part 6a suitably has a thickness which is at least 30% larger, preferably 1.5-3 times larger, than the thickness of the thinner parts 6b of the wall. The thinner parts 6b of the wall can, for example, have a thickness of about 0.5-2 mm.
    The first tubular wall 6 could alternatively have a constant wall thickness in its entire extent.
    The spray 11 of liquid medium which is injected into the mixing chamber 2 via the injection means 10 comes into contact in the mixing chamber with exhaust gases which via the inlet 7 of the mixing chamber flow into the mixing chamber in a substantially symmetrical flow around this spray 11. the mixing chamber 2 inflowing the exhaust gases carries the liquid medium downstream in the mixing chamber. During its movement downstream in the mixing chamber 2, the liquid medium spreads out into the exhaust gases and evaporates under the action of the heat of the exhaust gases. Liquid medium which has not had time to evaporate hits the above-mentioned part 6a of the first annular wall 6.
    The liquid medium hitting this wall part 6a will be narrowed under the action of the hot wall surface and the hot exhaust gases. From the mixing chamber 2, the exhaust gases are led on to the exhaust duct 12. Upon their passage through the throttle 14 in the exhaust duct 12, the exhaust gases are accelerated and flow at an increased speed along the outside of said wall part 6a while emitting heat thereto.
    The arrangement according to the invention is particularly intended for use in a heavy motor vehicle, such as for instance a bus, a towing vehicle or a truck.
    The invention is of course not in any way limited to the embodiments described above, but a number of possibilities for modifications thereof should be obvious to a person skilled in the art, without this departing from the basic idea of the invention as defined in the appended claims. .
    权利要求:
    Claims (5)
    [1]
    Arrangement for introducing a liquid medium, for example urea, into exhaust gases from an internal combustion engine, which arrangement (1) comprises: - a mixing chamber (2) intended to be flowed through by exhaust gases, the mixing chamber ( 2) is delimited in the radial direction outwards by a first tubular wall (6) of metal, and - an injection means (10) for injecting the liquid medium as a spray (11) into the mixing chamber (2), characterized therefrom, - that the arrangement (1) comprises an exhaust duct (12) adjacent to the mixing chamber (2), which is intended to be permeated by exhaust gases and extends along the outside of the first tubular wall (6), the exhaust duct (12) being delimited from the mixing chamber (2) of the first tubular wall (6), - that the exhaust duct (12) is delimited in radial direction outwards by a second tubular wall (13), which is designed to control the exhaust gases flowing through the exhaust duct (12) to pass on the outside of the n part (6a) of the first tubular wall (6) which is intended to be struck by said spray (11) of liquid medium from the injection means (10), and - that a throttle (14) is arranged in the portion (12a ) of the exhaust duct located on the outside of said wall part (6a) in order to cause in this exhaust duct portion (12a) an acceleration of the exhaust gases flowing through the exhaust duct (12) so that they flow at increased speed over the outside of said wall part (6a) ). 10 15 20 25 12
    [2]
    Arrangement according to claim 1, characterized in that said exhaust duct (12) is arranged downstream of the mixing chamber (2) and connected to the mixing chamber (2) via a flow reversing means (15), which is arranged to reverse the flow direction of the the exhaust gases flowing out of the mixing chamber (2) so that they are caused to flow through the exhaust duct (12) in a flow direction which is opposite to the flow direction of the exhaust gases in the mixing chamber (2).
    [3]
    Arrangement according to Claim 1 or 2, characterized in that the exhaust duct (12) and the mixing chamber (2) are concentric.
    [4]
    Arrangement according to any one of claims 1-3, characterized in that the first tubular wall (6) has a varying wall thickness seen in the longitudinal direction of the mixing chamber, said wall part (6a) having a wall thickness which is greater than the wall thickness of those of this wall part (6a) adjacent parts of the first tubular wall (6).
    [5]
    Arrangement according to one of Claims 1 to 4, characterized in that the injection means (10) is arranged in the center of the upstream end (4) of the mixing chamber and is arranged to inject the liquid medium in the direction of the downstream end (5) of the mixing chamber.
    类似技术:
    公开号 | 公开日 | 专利标题
    SE536832C2|2014-09-23|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine
    SE536062C2|2013-04-23|Arrangements equipped with heat transfer flanges for introducing a liquid medium into exhaust gases from an internal combustion engine
    SE535220C2|2012-05-29|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine
    SE535235C2|2012-06-05|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine
    SE1051014A1|2012-03-31|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine
    SE1251489A1|2014-06-22|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine
    US9194267B2|2015-11-24|Arrangement for introducing a liquid medium into exhaust gases from a combustion engine
    SE539138C2|2017-04-18|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine
    US20150075139A1|2015-03-19|Method for controlling an injector placed in a motor vehicle exhaust line
    SE1450417A1|2015-10-05|Exhaust after-treatment arrangement and a motor vehicle comprising such an exhaust after-treatment arrangement
    SE1150546A1|2012-12-17|Evaporator
    SE540984C2|2019-02-19|Method and apparatus for injecting a reducing agent into an internal combustion engine
    同族专利:
    公开号 | 公开日
    EP2935816B1|2019-02-20|
    SE536833C2|2014-09-23|
    RU2601694C1|2016-11-10|
    KR101721617B1|2017-03-30|
    WO2014098729A1|2014-06-26|
    EP2935816A1|2015-10-28|
    EP2935816A4|2016-08-24|
    KR20150092338A|2015-08-12|
    BR112015015089A2|2017-07-11|
    BR112015015089B1|2021-09-14|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CN107269364A|2016-03-31|2017-10-20|曼柴油机和涡轮机欧洲股份公司|Exhausted gas post-processing system and internal combustion engine|JP4332756B2|2007-12-25|2009-09-16|三菱自動車工業株式会社|Exhaust gas purification device for internal combustion engine|
    US8297050B2|2008-07-11|2012-10-30|GM Global Technology Operations LLC|Nozzle diffuser mixer|
    EP2358982B1|2008-12-17|2017-11-08|Donaldson Company, Inc.|Flow device for an exhaust system|
    JP5120463B2|2009-01-13|2013-01-16|トヨタ自動車株式会社|Exhaust gas purification device for internal combustion engine|
    DE102009036511A1|2009-08-07|2011-02-10|Friedrich Boysen Gmbh & Co. Kg|Exhaust system for e.g. diesel engine, has waste gas duct provided between input and exhaust gas treatment devices, and including deflection device for partial feedback of exhaust gas flow against main exhaust gas flow direction|
    KR20110063137A|2009-12-04|2011-06-10|현대자동차주식회사|Selective catalyst reduction device for exhaust system|
    US8173088B2|2010-02-24|2012-05-08|International Engine Intellectual Property Company, Llc|Method, system and apparatus for liquid injection into a gas system|
    SE535198C2|2010-09-30|2012-05-15|Scania Cv Ab|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine|
    FR2966512A1|2010-10-21|2012-04-27|Coutier Moulage Gen Ind|DEVICE FOR INTRODUCING A LIQUID ADDITIVE IN A THERMAL ENGINE EXHAUST LINE|
    SE535235C2|2010-10-22|2012-06-05|Scania Cv Abp|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine|CN108915830B|2016-06-13|2019-11-08|天纳克（苏州）排放系统有限公司|Exhaust aftertreatment mixing arrangement|
    KR101837555B1|2016-07-20|2018-03-12|융진기업 주식회사|SCR Mixer And SCR Apparatus Including The Same|
    CN110573708A|2017-02-24|2019-12-13|佛吉亚排放控制技术美国有限公司|Sprayer spray protector|
    US10954841B2|2017-10-05|2021-03-23|Caterpillar Inc.|Diesel exhaust fluid mixing|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1251489A|SE536833C2|2012-12-21|2012-12-21|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine|SE1251489A| SE536833C2|2012-12-21|2012-12-21|Arrangement for introducing a liquid medium into exhaust gases from an internal combustion engine|
    BR112015015089-6A| BR112015015089B1|2012-12-21|2013-12-05|ARRANGEMENT FOR INSERTING A LIQUID MEDIUM INTO DISCHARGE GASES FROM A COMBUSTION ENGINE|
    RU2015129708/06A| RU2601694C1|2012-12-21|2013-12-05|Device to feed fluid into internal combustion engine exhaust gases|
    EP13864459.6A| EP2935816B1|2012-12-21|2013-12-05|Arrangement to insert a liquid medium into exhausts from a combustion engine|
    PCT/SE2013/051458| WO2014098729A1|2012-12-21|2013-12-05|Arrangement to insert a liquid medium into exhausts from a combustion engine|
    KR1020157019142A| KR101721617B1|2012-12-21|2013-12-05|Arrangement to insert a liquid medium into exhausts from a combustion engine|
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