• 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 relates to an arrangement and a method for a dosing system for supplying a reducing agent in the exhaust gas from an internal combustion device such as a single-combustion engine. More particularly, the invention relates to how to identify an inadequate agent used as a reducing agent in an exhaust gas aftertreatment system. By sensing the temperature of the exhaust gases and comparing it with normal values which occur when using the correct reducing agent, indication of an inadequate agent can be indicated. The indication allows continued dosing of an incorrect agent to be stopped. If, for example, fuel is dosed instead of the intended reducing agent, the commercial temperature of the exhaust gases will exceed what can normally be expected and the damage that can occur as a result of too high exhaust gas temperatures can be avoided (Fig. 1)
    公开号:SE1051205A1
    申请号:SE1051205
    申请日:2010-11-17
    公开日:2012-05-18
    发明作者:Andreas Liljestrand；Per Bremberg
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    15 20 25 30 2 If fuel is filled into the tank intended for reducing agents and the fuel is metered into the exhaust line, there is a considerable risk that components in the exhaust aftertreatment system, e.g. the dosing system, catalysts, pipes or surrounding parts are damaged, at the same time as the requested reduction of emissions is absent and instead results in an actual increase in the emissions from the engine.
    There is thus a need to make it possible to detect whether other than the intended reducing agent has been filled into the tank and metered into the exhaust line.
    SUMMARY OF THE INVENTION The object of the present invention is to meet the above-mentioned needs. The object is achieved by an arrangement according to claim 1 and a method according to claim 6.
    The arrangement according to the invention comprises a temperature sensor located downstream of the catalyst. The temperature sensor is connected to a monitoring unit that compares the measured temperature in the exhaust gas downstream catalyst with a predetermined verified temperature range that can normally be expected when the correct reducing agent is supplied to the exhaust gas. If the measured temperature does not fall within the range, this is an indication that an agent other than the intended reducing agent is added to the exhaust gas by the dosing system.
    In an advantageous embodiment of the arrangement, the temperature range, which is the measured temperature, must be within about 50 ° C. This range provides reliable measurement and the necessary space for temperature variations which occur due to variations in, for example, ambient conditions, load level in the motor and the like.
    In one embodiment of the arrangement, the supply of agents from the dosing system to the exhaust gas stop is stopped if the measured temperature falls outside the predetermined range. This embodiment of the arrangement further increases safety against breakdowns and unwanted emissions when the media supply via the dosing system is automatically stopped when there is an indication of an incorrect means. In an embodiment of the arrangement, the control unit is connected to an instrument panel where a signal unit shows whether an agent other than the correct reducing agent is injected into the exhaust gas.
    This is a good solution to alert an operator that a problem exists and that corrective action is required to correct the error.
    In one embodiment of the arrangement, the exhaust line includes a filter arranged in the exhaust line downstream of the catalyst and where the temperature sensor is arranged downstream of the filter. This enables the temperature sensor to be placed where there is suitable space. It also means that other types of temperature sensors can be used which are active in other temperature ranges.
    The invention also relates to a method which makes it possible to determine in a simple and reliable manner whether the agent dosed from the dosing system tank is not the intended reducing agent.
    In one embodiment of the method, it also comprises the step of switching off the dosing of agents in the dosing system. This embodiment has the advantage that no manual shut-off is required if an incorrect agent in the dosing system has been identified.
    In a further embodiment, the method comprises the further subsequent steps after the dosing has been stopped comparing the temperature of the exhaust gases with expected temperatures when no dosing takes place. If this temperature is within the expected range, it is an indication that the other components of the dosing system are working properly. This embodiment of the method makes it possible to determine whether the error lies in which agent has been dosed or whether another error prevails in the arrangement.
    The invention also relates to a computer program comprising program code for implementing a method according to any of the described embodiments. The process can advantageously be carried out by a computer program which can continuously monitor the prevailing temperatures downstream of the catalyst and / or the filter to verify that reducing agents are metered into the exhaust gas. The invention also relates to an engine comprising at least one arrangement according to one of the embodiments above, which by means of a method as above can be used to determine whether an agent is dosed by the dosing system other than the intended reducing agent.
    Brief description of the figures Fig. 1 schematically shows an embodiment of the arrangement, and Fig. 2 shows a circuit diagram of a method according to the invention.
    Detailed Description of the Invention Exemplary Embodiments Fig. 1 shows a schematic arrangement according to the invention. The arrangement comprises an internal combustion engine 10 and an exhaust gas line 11 intended to direct combustion gases from the engine 10 to a suitable outlet. The size and design of the engine 10 can be varied in many ways to adapt to the vehicle or application where it is intended to function as a power source. The engine can thus alternatively be used for marine use or be part of a permanently installed engine for industrial use.
    From the engine 10, the exhaust gases are first led to a turbocharger 12, which is driven by the combustion gases. The turbocharger does not have to be included in the arrangement according to the invention and can therefore also be excluded without affecting the arrangement.
    The arrangement also includes a system for post-treatment of the exhaust gases from the engine in order to reduce the emissions such as reducing nitrogen oxides. To this end, the arrangement includes a dosing system 20 for dosing a reducing agent in the exhaust gas in the exhaust line 1. The dosing system 20 comprises a tank 21 intended to hold reducing agent, which may be a suitable aqueous solution of urea, commonly marketed under the name AdBlue. The reducing agent is led by means of a pump 22 which generates a pressurized flow in a supply line 23 and then is dosed in the exhaust flow by a dosing unit 24 arranged so that its mouth is located in the exhaust line 11. There are also other types of reducing agents whose shape and consistency can vary. The parts included are then adapted based on the selected reducing agent. The dosage of reducing agent is controlled by a control unit (not shown) which, based on various parameters such as, for example, the engine load and / or external influencing factors, determines the amount of reducing agent to be dosed. In order to ensure that the amount of reducing agent supplied to the dosing unit must always be sufficient, the pump 22 constantly generates a greater fate than that dosed and the excess is led from the dosing unit 24 back to the tank 21.
    Downstream of the dosing unit 24 in the exhaust line 11, a catalyst 13 is arranged and in which the reducing agent reacts with the nitrogen oxides in the exhaust gases and thereby purifies the exhaust gas. Such a catalyst is often called an SCR catalyst, the construction of which in itself constitutes a well-known technique. In the exhaust line 11 different types of filters can also be arranged to reduce the amount of particles in the exhaust gases. However, no filter is illustrated in the figure.
    Likewise, other components may be included in the exhaust line for reducing emissions, for example an ammonia abrasive catalyst arranged after the catalyst 13. The exhaust line may suitably also include a muffler for reducing noise. As these components are not necessary for understanding the invention, these components are not described in more detail.
    Downstream of the catalyst 13, and where appropriate also downstream of a filter, a temperature sensor 14 is provided for measuring the exhaust gas temperature T.
    The temperature sensor 14 measures the temperature T at selected intervals and sends the result to a monitoring unit 15. If additional components are included in the exhaust line, the temperature sensor 14 can be arranged before or after these, the important thing is that the temperature sensor 14 is placed downstream of the catalyst 13, regardless of additional components between the catalyst 13 and the temperature sensor 14. The monitoring unit 15 compares the measured temperature T against a predetermined temperature range Tmin - Tmax determined by testing which temperatures should normally prevail in the exhaust gas during continuous operation of the engine 10 and correctly performed dosing of reducing agent in the exhaust gas upstream of the catalyst 13. If the temperature T in the exhaust gas 14 measured by the temperature sensor 14 falls outside the desired temperature range determined, this is an indication that the agent dosed by the dosing unit 24 is not the intended reducing agent.
    As an example, if the tank 21 is accidentally (or intentionally) filled with diesel or other fuel instead of reducing agent, the temperature T in the exhaust gas downstream of the catalyst 13 will increase and exceed the highest temperature Tmax within the determined desired temperature range. The difference between Tmin and Tmax in this example is of the order of 50 ° ”, which allows for the normal variations that can occur during normal operation with correctly injected reducing agent.
    In other applications, temperature ranges can be significantly narrower, on the order of 10 ° or significantly larger on the order of 100 °. How large the temperature range should be is determined, among other things, by where the exhaust line temperature sensor 14 is located and whether there are other components between the temperature sensor 14 and the catalyst 13.
    Should it be indicated by the temperature comparison of the monitoring unit 15 that an incorrect reducing agent has been dosed in the exhaust line 11, the arrangement comprises means which make it possible to indicate this to an operator on a signal means intended for this purpose on an instrument panel. In addition, the monitoring unit 15 comprises means by its connection to the dosing unit 24 to be able to stop continued dosing of means in the exhaust line 11, as well as means to be able to switch off the dosing system.
    The shut-off of the dosing system 20 can be done manually by an operator when indicating that the wrong agent has been dosed, but it can also be done automatically by the monitoring unit 15 giving a suitable signal to the dosing unit 24.
    The arrangement described above operates on the basis of a method, an embodiment of which is illustrated in the circuit diagram in Fig. 2.
    The method comprises the steps of: a) The first step in the method is to determine if the agent is dosed by the dosing system 20 by the monitoring unit 15 communicating with the dosing system control unit. If agents are not dosed from dosing unit 24 then step a is repeated and if agents are dosed proceed to step b; 10 15 20 25 30 b) 0) d) 7 Then the prevailing temperature T downstream of the catalyst 13 is determined by means of the temperature sensor 14; The temperature measured by the temperature sensor 14 is compared with a predetermined temperature range (Tmin <T <Tmax) which normally applies when the correct reducing agent is dosed in the exhaust gas flow; if the measured temperature T falls within the range, the intended reducing agent is dosed, and step a is then repeated to verify again that this applies and if not, the procedure proceeds to step d; The measured temperature T is outside the range, which means that the wrong agent is dosed; the dosage should therefore be switched off. Once it has been determined that an incorrect agent has been dosed, this can be visualized to an operator so that the dosing system 20 can be switched off manually or it can be done automatically. The error can then be corrected.
    In this type of arrangement, of course, other errors can also occur and in order to increase the precision in troubleshooting, the procedure can be further supplemented. This is done by adding additional steps. These are: e) determine the prevailing temperature T downstream of the catalyst 13 after the dosing has been switched off; f) compares the measured temperature T with another predetermined g) h) temperature range with reference values (T 'min <T occurring temperatures when reducing agent is not dosed; but that it was not the intended reducing agent that has been dosed; suitably now the whole dosing system can be switched off to prevent incorrect agent being circulated in the dosing system; and take corrective action to ensure that the correct reducing agent is used before the dosing system is restarted. T does not within the range indicate that there is likely to be an error other than an incorrect reducing agent that has been dosed, for example an error in any sensor or the like; the dosage can therefore be turned on again to reduce nitrogen oxides in the exhaust gases; new; The invention has been described above on the basis of the example the embodiments that can of course be combined in different ways. An aqueous solution of urea has been given as an example of a properly intended reducing agent. A correct agent does not have to be in liquid form but can alternatively be an agent in both solid form and in gaseous form.
    The invention has mainly been described how it can be used to indicate that an incorrect reducing agent is used and that the tank has thus filled in and contains an incorrect reducing agent. Of course, the invention can also be used to indicate that a correct reducing agent is used, which is the case if the measured temperature in the exhaust gas range is within the predetermined range. Such an indication may consist of an absence of an error indication as described.
    Alternatively, the arrangement can be supplemented with a signal transmitter, for example in the form of a control lamp, which indicates that there is no fault.
    A simplified form of the invention can be used in the case where there is only a risk that the tank has filled with fuel or other means which risks causing an excessive temperature of the exhaust gases. In such a case, the lower limit of the predetermined temperature range can be set so low that the temperature in practice always exceeds the lower limit. In this case, the arrangement will in practice only indicate incorrectly injected means in the event that an excessively high temperature is measured in the exhaust gases.
    Corresponding problems and risks exist in the event that an incorrect mixture of a per se correct reducing agent is used in the dosing, which may occur if a partially filled tank were to be filled with water only.
    In an analogous manner, the invention can therefore in an alternative simplified embodiment be used to interrupt the dosing in case there is only a risk that the tank has filled with water or other means which risks that the intended temperature of the exhaust gases is never reached. If the tank 21 is accidentally filled with water so that the tank contains an incorrect mixture of reducing agent with a too low content of urea in the solution, the intended temperature increase in the exhaust gas will not be obtained, whereupon the measured temperature T will be below the lowest temperature. Tmin within the desired temperature range. In such a case, the upper limit of the predetermined temperature range can be set so high that the temperature in practice never reaches the upper limit.
    In this case, the arrangement will in practice only indicate incorrectly injected means in the event that a predetermined low temperature is not measured in the exhaust gases. In order to be able to identify this type of incorrectly injected agent, the measured exhaust gas temperature should be compared with other values for the temperature range. As the risk of damage due to too low an exhaust gas temperature is usually not as serious as the damage that can occur due to too high an exhaust gas temperature, in such a case the dosing can continue even after an indicated incorrect reducing agent. Even if the exhaust aftertreatment will not fully work then it can work with impaired function. It is then sufficient that an indication is given with a suitable signal means so that an appropriate action which corrects the error can be taken.
    When indicating that an incorrect agent has been dosed in the exhaust line, such a corrective measure suitably consists of emptying the tank of its contents and replacing it with a correct reducing agent.
    权利要求:
    Claims (10)
    [1]
    Arrangement of a dosing system (20) for supplying a reducing agent in the exhaust gas stream from an combustion device, comprising an exhaust line (11) which is intended to conduct combustion gases from a combustion device, a catalyst (13) arranged in the exhaust line (11) for purifying exhaust gas, and a dosing system (20) for supplying reducing agent to the exhaust gas upstream of the catalyst (13), characterized in that it comprises a temperature sensor (14) located downstream of the catalyst (13), the temperature sensor (14) being connected to a monitoring unit (15). comparing the measured temperature (T) with a predetermined temperature range normally prevailing when the intended reducing agent is dosed, wherein in the case the measured temperature (T) differs from the temperature range normally prevailing when the intended reducing agent is dosed, it is used to indicate that a an agent other than the intended reducing agent has been dosed by the dosing system (20).
    [2]
    Arrangement according to claim 1, characterized in that the predetermined temperature range is about 50 ° C.
    [3]
    Arrangement according to claim 1 or 2, characterized in that the arrangement comprises means for stopping the supply of means from the dosing system (20) to the exhaust gas if the measured temperature falls outside the predetermined temperature range.
    [4]
    Arrangement according to one of the preceding claims, characterized in that the monitoring unit (15) is connected to an instrument panel with a signal unit which, when indicating that an agent other than the intended reducing agent is dosed in the dosing system, shows that an agent other than the intended reducing agent is injected into exhaust fl fate.
    [5]
    Arrangement according to one of the preceding claims, characterized in that a filter is arranged in the exhaust line (11) downstream of the catalyst (13) and in that the temperature sensor (14) is arranged downstream of the filter. 10 15 20 25 30 11
    [6]
    A method of an arrangement according to any one of the preceding claims, wherein said method comprises the steps of: a) determining whether dosing is performed by the dosing system (20), and if not, repeating step a, if dosing takes place proceed to step b; b) determining the prevailing temperature (T) downstream of the catalyst (13); c) comparing the measured temperature (T) with a predetermined temperature range, and if the measured temperature (T) falls within the range, this indicates that the system is functioning properly, repeating step a, if not proceed to step d; d) to take appropriate action as the measured value is outside the range which means that the wrong agent is dosed.
    [7]
    The method of claim 6, wherein the step of step d comprises the step of: e) switching off the dosing of agents in the dosing system (20).
    [8]
    The method of claim 7, comprising the further steps of: f) determining the prevailing temperature (T) downstream of the catalyst (13); g) comparing the measured temperature (T) with a predetermined temperature range with reference values for desired temperatures when reducing agent is not dosed; h) switching off the dosing system (20) and taking appropriate action if the measured temperature (T) falls within the range indicating that the intended reducing agent is not dosed; unless the temperature (T) falls within the range, proceed to step i), i) turn on the dosage and repeat step a; as it did not help to stop the dosing, the error must be elsewhere in the arrangement.
    [9]
    Computer program comprising program code for implementing a method according to any one of claims 6 - 8.
    [10]
    An engine comprising an arrangement according to claims 1 - 5 which is used by means of a method according to claims 6 - 8 to determine whether an agent is dosed by the dosing system (20) other than the intended reducing agent.
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FR2898681A1|2006-03-16|2007-09-21|Inergy Automotive Systems Res|METHOD FOR DETERMINING THE CONCENTRATION OF A COMPONENT IN A SOLUTION|
    JP4710868B2|2007-04-25|2011-06-29|トヨタ自動車株式会社|Exhaust gas purification device for internal combustion engine|
    JP4428445B2|2007-09-05|2010-03-10|トヨタ自動車株式会社|Exhaust gas purification device for internal combustion engine|
    JP4840703B2|2007-11-16|2011-12-21|トヨタ自動車株式会社|Abnormality diagnosis device for exhaust purification system|
    FR2928969B1|2008-03-20|2010-09-10|Renault Sas|METHOD FOR DETECTING FAILURE OF AN INJECTION SOLENOID VALVE FOR THE EXHAUST OF A COMBUSTION ENGINE|
    JP4458182B2|2008-04-25|2010-04-28|トヨタ自動車株式会社|Diagnostic device for reducing agent supply device|
    DE102008040385A1|2008-07-14|2010-01-28|Robert Bosch Gmbh|Exhaust after-treatment device for an internal combustion engine with an SCR catalytic converter and method for operating an exhaust gas after-treatment device|
    US8166749B2|2009-02-12|2012-05-01|GM Global Technology Operations LLC|Exhaust treatment diagnostic system and method|
    JP5461057B2|2009-04-30|2014-04-02|日野自動車株式会社|Reducing agent abnormality detection method|
    法律状态:
    2017-07-04| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE1051205A|SE535363C2|2010-11-17|2010-11-17|Arrangement and method of a dosing system for supplying a reducing agent in the exhaust gas flow from a combustion device|SE1051205A| SE535363C2|2010-11-17|2010-11-17|Arrangement and method of a dosing system for supplying a reducing agent in the exhaust gas flow from a combustion device|
    EP11841923.3A| EP2640943A4|2010-11-17|2011-11-08|Arrangement and method for a dosing system for supply of a reducing agent in the exhaust flow from a combustion device|
    PCT/SE2011/051328| WO2012067566A1|2010-11-17|2011-11-08|Arrangement and method for a dosing system for supply of a reducing agent in the exhaust flow from a combustion device|
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