A detection method, device and filling machine for urea concentration detection

Abstract

The present invention specifically relates to a detection method, device, and dispensing machine for urea concentration testing. The detection method comprises: S10, obtaining a urea solution; S20, obtaining a first fluid resistance of a sphere in the urea solution at a first relative velocity and calculating a first measured concentration; S30, obtaining a second fluid resistance of the sphere in the urea solution at a second relative velocity and calculating a second measured concentration; S40, averaging the first and second measured concentrations to obtain a urea output concentration. The present invention utilizes fluid resistance to measure the concentration of the urea solution, offering the advantages of simple testing and rapid response.

Description

Technical Field

[0001] The present invention relates to the technical field of urea solution detection, and in particular to a detection method, a device and a filling machine for urea concentration detection. Background Art

[0002] Vehicle exhaust emissions will cause air pollution and environmental damage, and SCR (Selective Catalytic Reduction) technology can treat vehicle exhaust, decomposing environmentally polluting nitrogen oxides into nitrogen and water, thereby reducing the pollution of vehicle exhaust emissions to the atmospheric environment.

[0003] Urea solution is used to generate ammonia at high temperatures. With the support of SCR technology, ammonia reacts with nitrogen oxides to produce a redox reaction. Therefore, the quality (concentration) of urea solution is crucial to vehicle emissions. However, in actual use, if the urea solution concentration is too low, the redox reaction may be incomplete, resulting in residual nitrogen oxides. However, if the urea solution concentration is too high, it may poison the SCR catalyst. Therefore, the use of urea solution places high demands on its quality (concentration).

[0004] Prior to filling, urea dispensers typically test the concentration of the urea solution to ensure that the solution being dispensed meets the required concentration. For example, patent CN210426712U discloses a calibration device for a vehicle-use urea dispenser. This device primarily uses an electronic scale and a densitometer to test the urea solution concentration. While this method can verify the urea solution concentration, the volume-to-mass method only measures the concentration of the urea solution at the current temperature and is not universally applicable. Temperature fluctuations often lead to distortion in the urea solution concentration. This is particularly true at low temperatures. Since urea has a crystallization point of approximately -10°C, at low temperatures (even above zero), some urea in the urea solution in the urea dispenser may precipitate, resulting in an overestimated solubility. Furthermore, prior art also provides ultrasonic testing methods for urea solutions. However, ultrasonic waves are susceptible to urea foaming, causing attenuation and distortion, which in turn affects detection accuracy. Summary of the Invention

[0005] The present invention provides a detection method, a device and a filling machine for urea concentration detection, which have at least the advantages of small temperature interference, high detection accuracy, fast response and good self-detection performance.

[0006] First aspect

[0007] The present invention provides a detection method for urea concentration determination, comprising:

[0008] S10, obtaining a urea solution;

[0009] S20, obtaining a first fluid resistance of the sphere in the urea solution at a first relative speed, and calculating a first measured concentration based on the first relative speed and the first fluid resistance;

[0010] S30, obtaining a second fluid resistance of the sphere in the urea solution at a second relative speed, and calculating a second measured concentration based on the second relative speed and the second fluid resistance;

[0011] S40: Calculate the sum and average of the first measured concentration and the second measured concentration to obtain a urea output concentration.

[0012] Specifically, one of the main concepts of the present invention is to measure the concentration of the urea solution by means of fluid resistance, which has the advantages of simple testing and rapid response.

[0013] Furthermore, the calculation formula of the first measured concentration is: , C is the first measured concentration, ρ2 is the density of pure water, obtained based on the table, ρ1 is the density of urea solution, , ρ3 is the density of the sphere, R is the radius of the sphere, g is the acceleration of gravity, η is the dynamic viscosity of the flow, , F is the first fluid resistance.

[0014] Optionally, the second measured concentration is also calculated based on the above formula.

[0015] Furthermore, step S40 includes:

[0016] S41. Setting a correction coefficient to correct the urea output concentration.

[0017] Specifically, the correction coefficient is used to correct the calculation of urea output concentration through spherical resistance, so as to solve the defect of temperature interference.

[0018] Furthermore, the steps for obtaining the correction coefficient are as follows:

[0019] S31, after step S30, heating the urea solution to a pyrolysis temperature and allowing it to stand for a preset time;

[0020] S32, obtaining the amount of gas generated within the preset time, and calculating a third measured concentration based on the preset time and the amount of gas generated;

[0021] S33. The correction coefficient is the ratio of the third calculated concentration to the first calculated concentration.

[0022] Specifically, another key concept of the present invention is to utilize the pyrolysis reaction to provide the correction coefficient, thereby causing the urea output concentration measured by sphere resistance to approximate the actual urea concentration in solution. While ideally, urea completely dissolves in pure water at a concentration of 32.5%, in practice, urea solutions readily precipitate at low temperatures, resulting in incomplete hydrolysis of the urea. Consequently, the urea output concentration calculated by sphere resistance may contain errors. To correct this error, the present invention provides a correction coefficient through pyrolysis, thereby correcting the urea output concentration calculated by sphere resistance to approximate its actual concentration. It is worth noting that urea generates gases such as ammonia and carbon dioxide during pyrolysis, and the third urea concentration can be calculated using the gas-time curve.

[0023] Furthermore, when |the correction coefficient - 1| ≥ the fault tolerance rate, it is determined that the acquisition of the first fluid resistance is abnormal.

[0024] Specifically, since the urea solution forms attachments that adhere to the sphere, thereby affecting the measurement accuracy of the sphere, in order to avoid distortion of the urea concentration obtained through the resistance of the sphere, the abnormal state of the sphere is judged by the fault tolerance rate, so that the sphere is cleaned in time to ensure the accuracy of the measurement of the present invention.

[0025] Second aspect

[0026] The present invention provides a detection device for urea concentration detection, which is used in a detection method for urea concentration detection provided in any embodiment of the first aspect, comprising:

[0027] A sampling assembly and a detection assembly are arranged in sequence, with a first valve body being arranged between the detection assembly and the sampling assembly;

[0028] a controller, the controller being electrically connected to the first valve body and the detection assembly respectively;

[0029] The detection component includes a sphere, and the sphere has a resistance detection function.

[0030] Furthermore, a second valve body is provided after the detection assembly, and a pyrolysis assembly is provided after the second valve body;

[0031] The pyrolysis component has heating and gas collection functions;

[0032] The second valve body and the pyrolysis component are electrically connected to the controller respectively.

[0033] Furthermore, the pyrolysis component includes a reaction chamber, a heating component, and a thermal sensitive component;

[0034] A pressure sensor is arranged on the cavity wall of the reaction cavity or a gas collector is communicated with the reaction cavity.

[0035] Optionally, in terms of setting height, from high to low, the sampling component, detection component and pyrolysis component are arranged in order.

[0036] Optionally, the detection component includes a hollow cavity, the sphere is arranged in the cavity, and a force sensor is arranged on the surface of the sphere.

[0037] The third aspect

[0038] The present invention provides a filling machine for urea concentration verification, comprising a detection device for urea concentration verification as provided in any embodiment of the second aspect.

[0039] In summary, the present invention provides a detection method, device, and filling machine for urea concentration detection, which have at least the following advantages:

[0040] 1. The present invention uses fluid resistance to measure the concentration of urea solution, which has the advantages of simple testing and rapid response;

[0041] 2. The present invention utilizes the thermal decomposition reaction to provide the value of the correction coefficient, so that the urea output concentration measured by the sphere resistance approaches the actual concentration of urea in the solution, thereby correcting the error of the urea output concentration calculated by the sphere resistance, eliminating the technical problem of urea concentration measurement distortion caused by temperature and solubility issues, and making the urea concentration measurement accuracy of the present invention higher;

[0042] 3. The present invention uses the error tolerance rate to identify the abnormal state of the sphere, thereby cleaning the sphere in a timely manner to ensure the accuracy of the measurement of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will be described in further detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and should not be construed as limiting the scope of the present invention. Furthermore, unless otherwise specified, the drawings are merely schematic representations of the composition or structure of the depicted objects and may contain exaggerated representations. Furthermore, the drawings are not necessarily drawn to scale.

[0044] Figure 1 A schematic flow chart of a detection method for urea concentration determination provided by one embodiment of the present invention;

[0045] Figure 2 A schematic flow chart of a detection method for urea concentration determination provided by another embodiment of the present invention;

[0046] Figure 3 A schematic structural diagram of a detection device for urea concentration detection provided by one embodiment of the present invention;

[0047] 1. Sampling assembly; 2. Detection assembly; 3. First valve body; 4. Controller; 5. Second valve body; 6. Pyrolysis assembly; 11. Sampling tube; 21. Sphere; 61. Reaction chamber; 62. Gas collector. DETAILED DESCRIPTION

[0048] The following is combined with Figures 1 to 3 , the present invention is described in detail.

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0050] The main idea of ​​the present invention is to measure the concentration of urea solution by spherical resistance and to correct the detected solution concentration by a pyrolysis component, thereby having the advantages of fast and accurate detection and little interference from temperature and solubility.

[0051] See Figure 1 FIG2 is a flow chart of a detection method for urea concentration detection provided by one embodiment of the present invention.

[0052] Specifically, the present invention first obtains a urea solution in step S10, then obtains a first fluid resistance of a sphere in the urea solution at a first relative speed in step S20, and calculates a first measured concentration based on the first relative speed and the first fluid resistance. Then, in step S30, obtains a second fluid resistance of the sphere in the urea solution at a second relative speed, and calculates a second measured concentration based on the second relative speed and the second fluid resistance. Finally, in step S40, the first and second measured concentrations are summed and averaged to obtain a urea output concentration. In this manner, the concentration of the urea solution can be quickly obtained.

[0053] Optionally, the first relative speed may be that the urea solution flows, so that the sphere is in a flowing environment; or the urea solution remains stationary, and the sphere moves back and forth.

[0054] Optionally, the present invention can obtain the concentration of the urea solution by changing the relative speed multiple times and averaging multiple sets of data.

[0055] For further information, see Figure 2 FIG2 is a flow chart of a detection method for urea concentration detection provided by another embodiment of the present invention.

[0056] Specifically, the present invention further corrects the urea output concentration by setting a correction coefficient in step S41. Since the concentration of a urea solution is affected by the solubility of urea crystals, while the concentration of the urea solution can be quickly measured using sphere resistance, a correction coefficient is set to correct the urea output concentration in consideration of the possibility that the urea solution is not completely dissolved, thereby achieving higher accuracy.

[0057] Furthermore, the steps for obtaining the correction coefficient are as follows: first, through step S31, after step S30, heat the urea solution to the pyrolysis temperature and let it stand for a preset time; then, through step S32, obtain the amount of gas generated within the preset time, and calculate the third measured concentration based on the preset time and the amount of gas generated; finally, through step S33, the correction coefficient is the ratio of the third measured concentration to the first measured concentration.

[0058] It is understood that during initial operation, a correction coefficient is pre-set and then adjusted during subsequent measurements, so that the use of the correction coefficient is not interfered with by the pyrolysis process. It is worth explaining that because the pyrolysis reaction time is longer than the time for measuring the sphere resistance, in order to quickly obtain the urea output concentration calculated by the sphere resistance, a first correction coefficient is preset at the initial stage for use in system operation.

[0059] Optionally, the correction coefficient is summed and averaged based on multiple measurements, and the previous correction coefficient is used as the correction coefficient for obtaining the urea output concentration through the first measured concentration and the second measured concentration next time.

[0060] Optionally, the correction coefficient is the ratio of the third measured concentration to the second measured concentration.

[0061] Optionally, the correction coefficient is the ratio of the third measured concentration to the average of the first measured concentration and the second measured concentration.

[0062] Furthermore, when |the correction coefficient - 1| ≥ the fault tolerance rate, it is determined that the acquisition of the first fluid resistance is abnormal.

[0063] Optionally, the fault tolerance rate is 10%-20%.

[0064] It is worth explaining that under normal circumstances, the correction coefficient is generally a value greater than 1. If it is less than 1, there is an abnormality in the system.

[0065] For further information, see Figure 3 FIG2 is a schematic structural diagram of a detection device for urea concentration detection provided by one embodiment of the present invention.

[0066] Specifically, the present invention provides a detection device for urea concentration detection, comprising: a sampling component 1 and a detection component 2 arranged in sequence, with a first valve body 3 provided between the detection component 2 and the sampling component 1; a controller 4, wherein the controller 4 is electrically connected to the first valve body 3 and the detection component 2 respectively; the detection component 2 includes a sphere 21, and the sphere 21 has a resistance detection function.

[0067] Furthermore, a second valve body 5 is provided behind the detection assembly 2, and a pyrolysis assembly 6 is provided behind the second valve body 5; the pyrolysis assembly 6 has heating and gas collection functions;

[0068] The second valve body 5 and the pyrolysis component 6 are electrically connected to the controller 4 respectively.

[0069] Furthermore, the pyrolysis component 6 includes a reaction chamber 61 , a heating component, a thermal sensitive component; a pressure sensor disposed on the cavity wall of the reaction chamber 61 or a gas collector 62 connected to the reaction chamber 61 .

[0070] Optionally, in terms of setting height, from high to low, there are the sampling component 1, the detection component 2 and the pyrolysis component 6.

[0071] Optionally, the detection component 2 includes a hollow cavity, the sphere 21 is arranged in the cavity, and a force sensor is provided on the surface of the sphere 21.

[0072] Optionally, the sampling assembly 1 includes multiple sets of sampling tubes 11 for sampling urea solution at different points, thereby ensuring the reliability of the urea output concentration measured by the present invention. It is worth noting that the present invention only uses a small amount of the urea solution already configured in the filling machine for urea concentration measurement, thus having the advantages of simple operation and reliability.

[0073] Therefore, the working principle of the present invention is as follows: the first valve body 3 is opened by the controller 4 (the second valve body 5 is closed at this time) and the urea solution for measurement in the filling machine is obtained by using the sampling component 1, so that the ball 21 is immersed in the urea solution, and the first relative speed, first fluid resistance, second relative speed and second fluid resistance of the ball 21 are obtained by controlling the movement of the ball 21 or controlling the flow of liquid, and the urea output concentration is obtained through the first measured concentration and the second measured concentration, thereby realizing the measurement of the concentration of the urea solution in the filling machine.

[0074] Furthermore, after the urea output concentration is calculated, it is corrected using a correction coefficient.

[0075] Furthermore, after the calculation of the urea output concentration is completed, the second valve body 5 is opened to allow the urea solution to enter the pyrolysis component 6, and the pyrolysis component 6 is heated to the urea pyrolysis temperature, preferably above 300°C. After the pyrolysis is performed for a preset time, the third measured concentration is calculated based on the amount of gas generated, and then a correction coefficient is obtained based on the third measured concentration. The correction coefficient is uploaded to the controller 4 so that the urea output concentration can be corrected the next time the detection device measures the urea output concentration through the detection component 2.

[0076] The present invention has been described in detail above. Specific examples have been used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the present invention and its core concepts. It should be noted that those skilled in the art may make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A detection method for urea concentration determination, characterized in that: include: S10, obtaining a urea solution; S20. The detection assembly includes a hollow cavity, a sphere is disposed in the cavity, and a force sensor is disposed on the surface of the sphere to obtain a first fluid resistance of the sphere in the urea solution at a first relative speed, and calculate a first measured concentration based on the first relative speed and the first fluid resistance; the calculation formula for the first measured concentration is: C is the first measured concentration, ρ2 is the density of pure water, obtained based on a table, ρ1 is the density of the urea solution, , ρ3 is the density of the sphere, R is the radius of the sphere, g is the acceleration of gravity, η is the dynamic viscosity of the flow, F is the first fluid resistance; S30, obtaining a second fluid resistance of the sphere in the urea solution at a second relative speed, and calculating a second measured concentration based on the second relative speed and the second fluid resistance; the second measured concentration is calculated using the formula in step S20; S40, summing and averaging the first measured concentration and the second measured concentration to obtain a urea output concentration; Step S40 includes: S41, setting a correction coefficient to correct the urea output concentration; The steps for obtaining the correction coefficient are as follows: S31, after step S30, heating the urea solution to a pyrolysis temperature and allowing it to stand for a preset time; S32, obtaining the amount of gas generated within the preset time, and calculating a third measured concentration based on the preset time and the amount of gas generated; S33. The correction coefficient is the ratio of the third calculated concentration to the first calculated concentration.

2. A detection method for urea concentration determination according to claim 1, characterized in that: When |the correction coefficient - 1| ≥ the error tolerance rate, it is determined that the acquisition of the first fluid resistance is abnormal.

3. A detection device for urea concentration determination, used in the detection method for urea concentration determination according to any one of claims 1 to 2, characterized in that: include: A sampling assembly (1) and a detection assembly (2) are arranged in sequence, and a first valve body (3) is provided between the detection assembly (2) and the sampling assembly (1); A controller (4), wherein the controller (4) is electrically connected to the first valve body (3) and the detection component (2); The detection component (2) includes a sphere (21), and the sphere (21) has a resistance detection function; A second valve body (5) is provided behind the detection assembly (2), and a pyrolysis assembly (6) is provided behind the second valve body (5); The pyrolysis component (6) has heating function and gas collection function; The second valve body (5) and the pyrolysis component (6) are electrically connected to the controller (4) respectively; The detection component (2) comprises a hollow cavity; The sphere (21) is arranged in the cavity, and a force sensor is arranged on the surface of the sphere (21).

4. A detection device for urea concentration determination according to claim 3, characterized in that: The pyrolysis component (6) comprises a reaction chamber (61), a heating component, and a thermal sensitive component; A pressure sensor is arranged on the cavity wall of the reaction cavity (61) or a gas collector (62) is communicated with the reaction cavity (61).

5. A detection device for urea concentration determination according to claim 3, characterized in that: In terms of setting height, from high to low, there are the sampling component (1), the detection component (2) and the pyrolysis component (6).

6. A filling machine for urea concentration testing, characterized in that: It comprises a detection device for urea concentration detection as described in any one of claims 3 to 5.

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