• 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:
    The invention describes a device for supplying a reducing agent (22), e.g. urea, to an exhaust line (10) of a combustion engine (101 ). Before the reducing agent (22) is supplied to the exhaust line (10), carbon dioxide is added (29, 30, 31). A very turbulent flow of reducing agent is thus formed in the exhaust line and the problem of urea lumps in the exhaust line (10) is diminished. The invention relates to an engine with such a device and to a vehicle with such an engine.
    公开号:SE1151117A1
    申请号:SE1151117
    申请日:2011-11-24
    公开日:2013-05-25
    发明作者:Hanna Lind；Henrik Eriksson
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    2 The result is primitive polymers on urea base which form coatings on the inside of the exhaust line. Such coatings can eventually block an exhaust line.
    Many factors affect the formation of urea lumps and these can be roughly divided into exhaust wall and spray properties. The exhaust properties are, for example, temperature, composition, flow and flow. The wall property is, for example, the thermal conductivity of the wall material, external temperature at a given time and surface finish. Spray properties include droplet size distribution, spray angle velocity, temperature, dosing frequency and liquid density. Of course, daily factors such as injection position and injection angle relative to the exhaust gases, as well as the design of the nozzle, also play a role.
    As a solution to said problem, various ways have previously been proposed to ensure that the urea is better decomposed by directing the rays of the urea towards a grid as described in EP 1748162.
    Another variant of solution is described in EP 1781908, where the solution is that the injection is made in a heat-insulating pipe, so that the injected jets do not risk hitting cold surfaces in the exhaust line.
    According to a further variant described in WO 2006/084551, an injection system with a rotating nozzle part is used. The nozzle part is angled so that the nozzle can rotate by the reaction forces that the injection gives rise to.
    In order for this rotation to be as efficient as possible, it is required that the nozzles are arranged at a large radial distance from its center of rotation. This is in close proximity to the exhaust line walls which are the areas you want to avoid.
    Common to the known solutions is that they in different ways require that different components must be arranged in connection with the injectors and the devices thus become more or less expensive. In some cases, regular inspections and maintenance are also required, which further increases costs.
    OBJECT OF THE INVENTION An object of the invention is to provide a device which solves the problems found in the prior art. In particular, the invention relates to a device 3 and a method for increasing the turbulence when injecting a reducing agent into an exhaust line, so that the problem of urea lumps in the exhaust line is reduced.
    SUMMARY OF THE INVENTION According to the invention, these objects are achieved with a device according to claim 1.
    By dissolving carbon dioxide in the reducing agent, the carbon dioxide will want to be released when the reducing agent is injected into the exhaust line. The carbon dioxide thus contributes to creating a turbulent flow that spreads the reducing agent over a larger area. The turbulent flow causes large droplets in the reducing agent to break and the droplets to reach a higher speed. The cooling effect that occurs when the reducing agent hits the exhaust line also does not become so noticeable if the flow is turbulent, and the risk of unavoidable reducing agent sticking to the walls of the exhaust line decreases.
    All in all, the evaporation of the reducing agent increases when carbon dioxide is added.
    According to an embodiment of the invention, the carbon dioxide source is connected to the tank of the reducing agent. Thus, no separate container for the carbon dioxide is needed and the device takes up less space. Since modern vehicles consist of many components, lack of space is a common problem.
    According to another embodiment of the invention, the carbon dioxide source is connected to the line through which the reducing agent is transported from the tank to the injection system. The advantage of this is that only the amount of reducing agent that is currently supplied to the exhaust line is pressurized. It is then possible to regulate the amount of carbon dioxide in the reducing agent in a more accurate manner and the risk of incorrect dosing of carbon dioxide is reduced.
    According to a further embodiment of the invention, the carbon dioxide is supplied to the line under pressure. The need for a separate component in the form of a pump is then reduced.
    According to another embodiment, a pump is arranged on the line. The pump increases the pressure in the line and helps to create the desired turbulent flow.
    According to one embodiment of the invention, the reducing agent is urea.
    The above-mentioned objects are also achieved with an internal combustion engine comprising a device according to the invention, and a vehicle comprising such an engine.
    LIST OF FIGURES Figure 1 schematically shows a vehicle with an engine according to the invention.
    Figure 2 schematically shows a detail of an exhaust line with a device according to the invention.
    Figure 2a schematically shows a detail of an injection system according to the invention.
    Figure 3 schematically shows an embodiment of a device according to the invention.
    Figure 4 schematically shows another embodiment of a device according to the invention.
    Figure 5 schematically shows another embodiment of a device according to the invention.
    DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a vehicle 100 equipped with an internal combustion engine 101 according to the invention. In the figure, the vehicle is shown as a heavy truck, but the invention can also be practiced on other types of vehicles, for example construction vehicles or buses.
    The invention can also be practiced with stand-alone engines, for example with reserve power plants, or with boat engines.
    Figure 2 schematically shows a part of an exhaust line 10 to an internal combustion engine 101 according to the invention. On the exhaust line 10 there is a bend 10a where the risk of und evaporated reducing agent accumulates. The exhaust line 10 opens into a catalyst 12 in which harmful substances in the exhaust gases are converted. Reducing agent is supplied to the exhaust line 10 via an injection system 23. The injection system 23 is shown in detail in Figure 2a. Reducing agent 22 is supplied to the injection system 23 via a line 21. The reducing agent 22 is supplied to the injection system 23 under pressure. A normal pressure is between 3.3-3.8 bar. This pressure can be achieved by pressurizing the tank 20 (see Figure 3) in which the reducing agent 22 is stored, or by placing a pump (not shown) on the line 21 between the tank 20 and the injection system 23. Figure 2a shows that the dosage of reducing agent 22 is pressurized by means of compressed air 40 (see figure 3) via a compressed air line 41. The pressure in the compressed air 40 is approximately 8 bar, but can also be approximately 4 bar. The pressure of the compressed air 40 depends on the actual dosage of reactant 22.
    A control unit 35 dispenses reducing agent 22 depending on the current travel case of the internal combustion engine 101 and adjusts the pressure in the compressed air 40 after the current metering, so that the emissions from the internal combustion engine 101 are as low as possible. The injection system 23 comprises a nozzle 24 with outlets in the form of small holes. There are several different ways of designing the holes 25 depending on the type of flow desired. For example, a single conical hole can be used to supply the reducing agent. The holes 25 may be provided on the side of the nozzle 24, as shown in Figure 2a, but they may also be provided on the end face 26 of the nozzle 24.
    The end surface 26 of the nozzle 24 may also be conical and provided with holes. The nozzle 24 may also be provided with an internal vortex chamber (not shown). Since the design of the nozzle is only a part of the factors that affect the formation of urea lumps, other factors must also be considered when choosing a nozzle.
    As the reducing agent passes the nozzle, the pressure drops rapidly and a mist with droplets forms. It is desirable that the droplets be small because the reducing agent is then more rapidly converted to a desired compound. If the reducing agent is, for example, urea, the droplets are converted into ammonia, among other things. Smaller droplets also have a smaller amount of movement, which makes the droplet more easily follow the gas flow and hit the wall of the exhaust pipe 10 at a greater distance than a larger droplet does. Larger droplets lead to the evaporation of reducing agent taking longer and the risk of solid deposits of reducing agent 22 on the walls of the exhaust line 10 increases. Larger droplets also have a lower rate which is not favorable for the evaporation of reducing agent. The reducing agent 22 may be urea dissolved in water, for example Adblue W 'which contains a concentration of 32.5% urea.
    Figure 3 shows an embodiment of the invention. A pressurized container 29 with carbon dioxide is connected to the line 21 so that, when the reducing agent 22 reaches the injector 23, carbon dioxide is dissolved in the reducing agent 22. The container 29 can be, for example, a carbon dioxide cartridge. The supply of carbon dioxide is controlled by the control unit 35. It is also conceivable that a separate control unit controls the supply of carbon dioxide, alternatively that another control unit present on the vehicle 100 controls the supply of carbon dioxide, for example the control unit for the internal combustion engine 101. 6 pressure between 7.5 and 8.5 bar, especially 8 bar. The concentration of carbon dioxide in the reducing agent depends on the temperature.
    As the temperature of the parts included in the system varies, the concentration of carbon dioxide in the reducing agent 22 will also vary. A higher pressure risks creating a separation between gas and liquid, which complicates a correct dosing, while a lower pressure risks not creating sufficient turbulence in the reducing agent 22.
    Figure 4 shows another embodiment of the invention. Here, carbon dioxide is added to the compressed air line 41 instead of to the line 21 for reducing agent 22. This embodiment requires fewer modifications to the existing system and therefore becomes easier and cheaper to implement.
    Figure 5 shows another alternative embodiment where the carbon dioxide is added directly to the tank. The entire tank 20 is pressurized in this embodiment. For example, pressurization can take place by supplying gas, eg carbon dioxide, to the tank under high pressure. It is also conceivable to also in this case arrange a pump (not shown) on the line 21 to increase the turbulence in the reducing agent.
    According to the invention, the possibility of a very turbulent flow is given when a reducing agent is injected into an exhaust line, by adding carbon dioxide to the reducing agent. The turbulent flow creates small drops of the reducing agent and the drops get a higher speed. This reduces the risk of urea clumps forming on the walls of the exhaust line and reduces the problem of blockage of the exhaust line.
    The invention is in no 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 (8)
    [1]
    An apparatus for injecting a reducing medium (22) into an exhaust line (10) at an internal combustion engine (101) comprising a tank (20) containing the reducing agent (22), an injection system (23) provided with a nozzle (24) having an outlet (24) 26) from which the reducing agent (22) can be injected into the exhaust line (10), a line (21) connecting the injection system (23) to the tank (20), characterized in that the device comprises a carbon dioxide source (29, 30) arranged to supply carbon dioxide to the reducing agent (22).
    [2]
    Device according to Claim 1, characterized in that the carbon dioxide source is connected to the tank (20) of the reducing agent.
    [3]
    Device according to Claim 1, characterized in that the carbon dioxide source (29, 30) is connected to the line (21).
    [4]
    Device according to one of the preceding claims, characterized in that the carbon dioxide source (29) is pressurized.
    [5]
    Device according to one of the preceding claims, characterized in that a pump (28) is arranged on the line (21).
    [6]
    Device according to Claim 5, characterized in that the pump (28) is arranged between the carbon dioxide source (29, 30) and the injection system (23).
    [7]
    Device according to claim 1, characterized in that the reducing agent is urea.
    [8]
    Internal combustion engine (101) comprising a device according to any one of the preceding claims. A vehicle (100) comprising an internal combustion engine (101) according to claim 8.
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    同族专利:
    公开号 | 公开日
    WO2013077799A1|2013-05-30|
    SE536182C2|2013-06-18|
    DE112012004537T5|2014-08-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP3551779B2|1997-12-19|2004-08-11|トヨタ自動車株式会社|Internal combustion engine having lean NOx catalyst|
    DE10237165B4|2002-08-14|2015-05-13|Robert Bosch Gmbh|Apparatus and method for exhaust treatment of a combustion device and their use|
    法律状态:
    2021-06-29| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE1151117A|SE536182C2|2011-11-24|2011-11-24|Device for injecting reducing agent into an exhaust pipe|SE1151117A| SE536182C2|2011-11-24|2011-11-24|Device for injecting reducing agent into an exhaust pipe|
    PCT/SE2012/051276| WO2013077799A1|2011-11-24|2012-11-20|Device for injection of reducing agent together with carbon dioxide in an exhaust line|
    DE112012004537.8T| DE112012004537T5|2011-11-24|2012-11-20|Device for injecting a reducing agent together with carbon dioxide into an exhaust pipe|
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