• 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 a measuring device (2) adapted to control a liquid (4) which is used as a reducing agent in connection with exhaust gas purification for exhaust gases from an internal combustion engine. The measuring device comprises a temperature sensor (6) adapted to the measuring temperature in the liquid, a sound speed measuring unit (8) adapted to measure the speed of sound in the liquid. The temperature sensor is adapted to determine a first temperature T1 for the liquid, and output a temperature signal (12) to a calculation unit (10) depending thereon; ) to the calculation unit (10) depending thereon. The temperature sensor (6) is further adapted to determine a second temperature T2 for the liquid and output a temperature signal (12) to the calculation unit depending thereon, and the calculation unit (10) is adapted to calculate the absolute value of one temperature difference AT between T1 and T2, AT = | T1-T2 | , and comparing AT with a predetermined threshold value TTH. If AT exceeds TTH, a control signal (16) is emitted to the sound speed measuring unit (8) to determine a second sound speed v; for the liquid wide temperature T2 and emitting a speed of sound signal (14) to the calculation unit (10) depending thereon, the calculation unit being adapted to compare v1 and v; with a first vmf and a second vmf, respectively; velocity reference values for a reference liquid wide temperatures T1 and T2, respectively. An indication signal (18) is generated depending on the result of the comparison, and wherein the indication signal (18) indicates that the liquid is approved by the measured values v1 and v; is within the approved speed range the pre-reference values, and that the liquid is not approved if the values v1 and v; does not fall within the said approved speed ranges. (Figure 2)
    公开号:SE1150657A1
    申请号:SE1150657
    申请日:2011-07-11
    公开日:2013-01-12
    发明作者:Fredrik Straaaat；Sebastian Zamani
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    15 20 25 30 2 depending on the storage level. In order to maintain a high conversion efficiency during different operating conditions, the NH3 layer must be maintained. However, as the temperature of the SCR catalyst increases, the NH 3 level must be reduced to avoid NH 2 emissions (ie, excess NH 2 is emitted from the SCR catalyst), which may reduce the conversion efficiency of the catalyst.
    In summary, in order to meet stricter environmental requirements, all vehicle manufacturers use SCR catalyst systems to purify exhaust gases from nitrogen oxides (N OX). This is done by injecting ammonia solution into an SCR catalyst that helps convert NOX particles into nitrogen and water. The exhaust gas purification strategy should take into account that enough NOX is converted while not wanting to inject too much reducing agent, out of consideration for both the driving economy and the environment.
    Within the EU, for example, there are requirements for exhaust emission levels and the type of reducing agent to be used. Among other things, future requirements may require that the quality of the reducing agent used be determined.
    One way to determine the quality of reducing agents is to measure the speed of sound in combination with measuring the temperature.
    The speed of sound in liquids can be determined by the formula: Vliquid = * / (K (P) / D (T)) where K (p) = the compression factor of the liquid which depends on the pressure p, and p (T) = the density of the liquid.
    Since the density of liquids is temperature dependent, this must be compensated for. This is done by measuring the temperature of the liquid. In the same way, the compression factor of the liquid is pressure-dependent, but to a very small extent (around atmospheric pressure).
    Figure 1 is a graph schematically showing the relationship between the speed of sound (rn / s) and the temperature of a different number of liquids. The figure shows curves for the following liquids: A; Giykoi 10 15 20 25 30 B: AdBlue type urea C: Diluted AdBlue D: Water The graph shows that different liquids have different sound velocities at different temperatures. However, there are liquids where the speed of sound is equal at the same temperature. Two examples of this are glycol and salt water which at ~ 35 ° C have the same speed of sound as AdBlue. In order to separate these liquids, according to a known device, a conductivity sensor is also used and the conductivity of the liquids is determined. Because the conductivity of AdBlue differs from the conductivity of glycol, it is possible to distinguish liquids. However, the introduction of an additional sensor entails an increased complexity and thus an increased cost and a greater risk of errors. In addition, the conductivity can differ significantly for AdBlue from different manufacturers, which also means that the risk of errors increases.
    Making measurements on a ureal solution with an acoustic sensor is described in a number of patent documents which are briefly discussed below.
    US-2008/0280371 relates to an acoustic sensor adapted to measure the concentration of urea.
    Changes in the molecular weight of urea affect the speed of sound, which can be used to determine the concentration. The acoustic sensor can be combined with an NH3-sensitive sensor that is used to ensure that it is urea.
    DE-10200601323 relates to a method for determining the concentration of ureal solution in a liquid based on the speed of sound in the liquid determined with ultrasonic sensors.
    The presented documents show devices for determining the urea quality, but there is no comparison with other liquids.
    The object of the present invention is to provide a method and a device which can ensure that the reducing agent is approved, and which can achieve this in a way which does not increase the complexity of the measurements and which thus does not increase the cost and the risk of errors. Summary of the Invention The above objects are achieved with the invention defined by the independent claims.
    Preferred embodiments are defined by the dependent claims.
    According to the invention, the speed of sound is evaluated over a certain period of time, which means that the quality measurement can be made more accurate and that it can then be determined with greater certainty which type of liquid is in the tank intended for reducing agents. This can be done completely without conductivity measurement.
    The present invention is based on the fact that the speed of sound differs at different temperatures. The different operating conditions of the vehicle give rise to different temperatures of the liquid in the tank intended for reducing agents where the temperature varies over time, t-eX-i Tnatta Tvintera Tdrifta Tstopa Tvila- By determining the sound speed of the liquid contained in the tank intended for reducing agents at at least two different temperatures and compare these measured velocities with reference values for the velocity of a reference liquid, i.e. an approved liquid, one can obtain information regarding the degree of correspondence between the liquid and the reference liquid, and whether the liquid contained in the tank corresponds sufficiently, ie. is within a given range, the conclusion is that that liquid is approved.
    In some cases it happens that the liquid in the tank intended for reducing agents does not reach the temperature of the liquid required to be able to make the quality measurement / distinction you wish to carry out. Then, according to a preferred embodiment, the existing heating systems can be used to thaw the liquid in hoses and in the tank to raise the temperature.
    The electrically heated hoses and water valves, which help to circulate engine cooling water in the tank with the liquid, are controlled by a control unit in the vehicle which also communicates with the calculation unit in the measuring device. The invention has, among other things, the advantage that it is possible to separate your different liquids without using a conductivity sensor.
    According to a further preferred embodiment, an atmospheric pressure sensor can be used to calculate the compression factor of the liquid and thereby further increase the accuracy of the measurement.
    Brief description of the drawing Figure 1 is a graph that schematically shows the relationship between sound speed and temperature for different liquids.
    Figure 2 is a schematic block diagram illustrating the present invention.
    Figure 3 is a fate diagram illustrating the method of the present invention.
    Detailed Description of Preferred Embodiments of the Invention Referring to the block diagram of Figure 2, the invention will now be described.
    The invention comprises a measuring device 2 adapted to control a liquid 4 which is used as a reducing agent in connection with exhaust gas purification for exhaust gases from an internal combustion engine (not shown). Preferably, the internal combustion engine is arranged on a vehicle, e.g. a truck or bus, but other applications are also possible, for example on a boat or in the mechanical industry.
    The reducing agent is, for example, a urea solution, e.g. of the AdBlue type.
    The measuring device 2 comprises a temperature sensor 6 adapted to measure the temperature in the liquid, a sound speed measuring unit 8 adapted to measure the speed of sound in the liquid 4. Often a level meter (not shown) is also provided to measure the level of the liquid 4 in the tank intended for reducing agents.
    The sound velocity measuring unit 8 may be a conventional acoustic meter consisting of a transmitter which emits an acoustic wave into the liquid 4, and a receiver which detects the reflected sound wave. Other acoustic meters can also be used within the scope of the present invention.
    The size of the tank intended for reducing agents is known and thereby the speed of sound can be easily calculated. This is done by measuring the time from the time the wave is transmitted until the reflected sound path is detected and the speed is calculated by dividing the distance by the measured time.
    The measuring device 2 further comprises a calculation unit 10.
    The temperature sensor 6 is adapted to determine a first temperature T1 for the liquid 4, and to output a temperature signal 12 to the calculation unit 10 accordingly. Furthermore, the sound speed measuring unit 8 is adapted to determine a first sound speed v1 of the liquid 4 at the temperature T1 and to output a sound speed signal 14 to the calculation unit 10 depending on a measured speed.
    The temperature sensor 6 is adapted to determine a second temperature T2 for the liquid 4 and to output a temperature signal 12 to the calculation unit as a function thereof.
    The calculation unit 10 is adapted to calculate the absolute value of a temperature difference mellanT between T1 and T2, i.e. AT = | T1-T2 | , and comparing AT with a predetermined threshold value TTH. If AT exceeds TTH, a control signal 16 is output to the sound speed measuring unit 8 to determine a second sound speed v; for the liquid 4 at the temperature T2 and emit a sound speed signal 14 to the calculation unit 10 depending on the measured speed.
    According to one embodiment, TTH is 2 ° C, but can be selected to any suitable value greater than 1 ° C.
    In other words, the measurement of the second sound speed v; occur when the temperature difference exceeds the threshold value TTH.
    The temperature networking can, for example, take place continuously with a predetermined measuring interval, for example in the order of a few seconds or minutes, and only when the temperature difference is sufficiently large does the speed measurement take place.
    The calculation unit 10 is then adapted to compare v1 and v; with a first vmfl and a second vfef, respectively; velocity reference value for a reference liquid at temperatures T1 and T2, respectively, and to generate an indication signal 18 depending on the result of the comparison. The reference liquid is, for example, a ureal solution that meets all quality requirements. The indication signal 18 indicates that the liquid 4 is approved if the measured values v1 and vg are within approved speed ranges for the reference values - the indication signal 18 then contains e.g. the information "OK", and that the liquid 4 is not approved if the values v; and V; is not within the said approved speed ranges, and the indication signal 18 then contains e.g. the information "not OK".
    The approved speed ranges can, for example, be selected as a maximum percentage deviation from the speed reference values. This deviation can be in the order of one or a few percent, for example a maximum of 5%.
    As discussed above, the liquid 4 in the tank intended for reducing agents exhibits different temperatures depending on the different operating conditions in which the vehicle may be.
    Sometimes, however, it may be desirable to carry out the measurement even when the liquid 4 has not changed temperature due to the operating condition of the vehicle.
    The device then comprises, according to an embodiment, a heating device 20 adapted to heat the liquid 4 in a controlled manner after v1 has been determined. For example, the heating device 20 may be the heating systems available for thawing the reducing agent in hoses and in the container. The heating device can be controlled by a control signal 22 generated by the calculation unit 10.
    Of course, it is possible, within the scope of the invention, to determine at least one further temperature value and, in that case, compare the further determined temperature value (s) with the previously determined temperature values, form temperature differences and if these differences exceed certain threshold values determine speed values at the temperature or temperatures compared with the corresponding velocity reference values of the reference liquid. This would further increase the security of the measurements.
    With reference to Figure 3, which shows a fate diagram illustrating the method according to the invention, the method will now be described in detail. The invention thus also relates to a method for controlling a liquid which is used as a reducing element in connection with exhaust gas purification for exhaust gases from an internal combustion engine.
    The method comprises the steps of: a) determining a first temperature T1 for the liquid; b) determining a speed of sound v1 of the liquid at the first temperature T1; c) determining a second temperature T2 for the liquid; d) calculate the absolute value of a temperature difference AT between T1 and T2, AT = | Ti-Tz | ; e) compare AT with a predetermined threshold value TTH. The threshold value TTH is preferably 2 ° C, but can also be selected to any suitable value greater than 1 ° C.
    If AT exceeds TTH, the steps of: f) determining a second sound velocity v are performed; for the liquid at temperature T2; g) comparing V1 and v; with a first vm fl and a second vref, respectively; velocity reference value for a reference liquid at temperatures T1 and T2, respectively, and h) generating an indication signal depending on the result of the comparison.
    The indication signal indicates that the liquid is approved if the measured values v1 and v; is within the approved speed range for the reference values, and that the liquid is not approved if the values V1 and v; does not fall within the said approved speed ranges.
    The approved reference liquid is, for example, fl surface urea that meets all quality requirements.
    As discussed above, in some contexts it may be relevant to instead actively heat the liquid in a controlled manner, which then takes place between step b and step c.
    Additional temperature nets can also be made by determining at least one further temperature value and comparing the further determined temperature value (s) with the previously determined temperature values, forming temperature differences and if these differences exceed certain threshold values determining speed values at the temperature or temperatures compared with speed reference values. for the reference liquid. This is to obtain even more reliable measurement results. The present invention is not limited to the above-described preferred embodiments.
    Various alternatives, modifications and equivalents can be used. The above embodiments are therefore not to be construed as limiting the scope of the invention as defined by the appended claims.
    权利要求:
    Claims (10)
    [1]
    A method for controlling a liquid used as a reducing agent in connection with exhaust gas purification for exhaust gases from an internal combustion engine, characterized in that the method comprises the steps of a) determining a first temperature T1 for the liquid; b) determining a speed of sound v1 of the liquid at the first temperature T1; c) determining a second temperature T2 for the liquid; d) calculate the absolute value of a temperature difference AT between T1 and T2, AT = | Ti-Tz | ; e) comparing AT with a predetermined threshold value TTH; and if AT exceeds TTH, f) determining a second sound rate v; for the liquid at the second temperature T2; g) comparing v1 and v; with a first vmf1 and a second v1e1, respectively; velocity reference value for a reference liquid at the temperatures T1 and T2, respectively, and h) generating an indication signal depending on the result of the comparison, the indication signal indicating that the liquid is approved if the measured values v1 and v; is within the approved speed ranges for the reference values, and that the liquid is not approved if the values v1 and v; does not fall within the said approved speed ranges.
    [2]
    The method of claim 1, wherein the TTH is 1 ° C.
    [3]
    The method of claim 1 or 2, wherein the method comprises, after a) and b), heating the liquid in a controlled manner.
    [4]
    The method according to any one of claims 1-3, wherein the method comprises determining at least one further temperature value for the liquid and comparing the further determined temperature value (s) with the previously determined temperature values, forming temperature differences and if these differences exceed certain threshold values determining velocity values at the temperature or temperatures compared to velocity reference values of the reference liquid. 10 15 20 25 30 ll
    [5]
    The method according to any one of claims 1-4, wherein the reference liquid is fl surface urea.
    [6]
    A measuring device (2) adapted to control a liquid (4) used as a reducing agent in connection with exhaust gas purification for exhaust gases from an internal combustion engine, the measuring device comprises a temperature sensor (6) adapted to measure the temperature in the liquid, a sound speed measuring unit (8) adapted measuring the speed of sound in the liquid, characterized in that the measuring device comprises a calculation unit (10), and that the temperature sensor is adapted to determine a first temperature T1 for the liquid, and outputs a temperature signal (12) to the calculation unit in dependence thereof; the sound velocity measuring unit (8) is adapted to determine a first sound velocity v1 of the liquid at the first temperature T1 and output a sound velocity signal (14) to the calculation unit (10) depending thereon; the temperature sensor (6) is adapted to determine a second temperature T2 for the liquid and output a temperature signal (12) to the calculation unit accordingly, the calculation unit is adapted to calculate the absolute value of a temperature difference AT between T1 and T2, AT = | Tl-T2 | , and comparing AT with a predetermined threshold value TTH; and if AT exceeds TTH; outputting a control signal (16) to the sound speed measuring unit (8) to determine a second sound speed V; for the liquid at the second temperature T2 and outputting a speed of sound signal (14) to the calculation unit (10) depending thereon, the calculation unit being adapted to compare v1 and v; with a first vmfl and a second vref, respectively; velocity reference value for a reference liquid at temperatures T1 and T2, respectively, and to generate an indication signal (18) depending on the result of the comparison, and wherein the indication signal (18) indicates that the liquid is approved if the measured values v1 and v; is within the approved speed range for the reference values, and that the liquid is not approved if the values V1 and v; does not fall within the said approved speed ranges.
    [7]
    The measuring device according to claim 6, wherein the TTH is 1 ° C.
    [8]
    The measuring device according to claim 6 or 7, wherein the device comprises a heating device (20) adapted to heat the liquid in a controlled manner after v1 has been determined.
    [9]
    The measuring device according to any one of claims 6-8, wherein the device is adapted to determine at least one further temperature value and compare the further determined temperature value (s) with the previously determined temperature values, form temperature differences and if these differences exceed certain threshold values determine speed values at the temperature or temperatures compared with the corresponding velocity reference values of the reference liquid.
    [10]
    The measuring device according to any one of claims 6-9, wherein the reference liquid is liquid urea.
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1150657A|SE535967C2|2011-07-11|2011-07-11|Method for controlling a fluid|SE1150657A| SE535967C2|2011-07-11|2011-07-11|Method for controlling a fluid|
    EP12810997.2A| EP2732280A4|2011-07-11|2012-07-03|Method and device for testing a liquid|
    PCT/SE2012/050765| WO2013009240A1|2011-07-11|2012-07-03|Method and device for testing a liquid|
    US14/131,545| US20140157879A1|2011-07-11|2012-07-03|Method and device for testing a liquid|
    KR1020147003585A| KR20140036319A|2011-07-11|2012-07-03|Method and device for testing a liquid|
    JP2014520164A| JP2014521931A|2011-07-11|2012-07-03|Methods and devices for testing liquids|
    RU2014104564/28A| RU2564687C2|2011-07-11|2012-07-03|Method and device for fluid testing|
    BR112014000635A| BR112014000635A2|2011-07-11|2012-07-03|method and device for testing a liquid|
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