Detection method and device for urea concentration verification and filling machine

Abstract

The invention particularly relates to a detection method and device for urea concentration verification and a filling machine. The detection method comprises the following steps: S10, obtaining a urea solution; s20, acquiring first fluid resistance of the sphere in the urea solution at a first relative speed, and calculating a first measured concentration; s30, acquiring second fluid resistance of the sphere in the urea solution at a second relative speed, and calculating a second measured concentration; and S40, summing and averaging the first relative speed and the second relative speed to obtain the urea output concentration. The concentration of the urea solution is measured in a fluid resistance mode, and the method has the advantages of being simple in test and rapid in reaction.

Description

Technical Field

[0001] The 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 and decompose environmentally polluting nitrogen oxides into nitrogen and water, thereby reducing the pollution of vehicle exhaust emissions to the atmospheric environment.

[0003] Among them, urea solution is used to produce ammonia at high temperature, and with the support of SCR technology, ammonia and nitrogen oxides are used to produce redox reactions. Therefore, the quality (concentration) of urea solution is crucial to vehicle emissions. However, in the actual use of urea solution, if the concentration of urea solution is too low, it is easy to cause insufficient redox reaction to produce residual nitrogen oxides; and if the concentration of urea solution is too high, it is easy to cause SCR catalyst poisoning. Therefore, the use of urea solution has high requirements for its quality (concentration).

[0004] In the prior art, the urea filling machine will detect the concentration of the urea solution before filling the urea solution to ensure that the concentration of the urea solution injected into the vehicle meets the use requirements. For example, patent CN210426712U discloses a vehicle urea filling machine calibration device, which mainly detects the concentration of the urea solution by an electronic scale and a density meter. Although the concentration of the urea solution can be calibrated, the volume mass measurement method can only measure the concentration of the urea solution at the current temperature, which is not universal. The concentration measurement of the urea solution is often distorted due to temperature fluctuations. Especially for low temperature conditions, since the crystallization point of urea is about minus 10°C, when the temperature is low (even above zero), the urea in the urea preparation solution in the urea filling machine is partially precipitated, resulting in a situation where the detection solubility is high. At the same time, the prior art also provides an ultrasonic detection method for urea solution, but the ultrasonic wave is susceptible to the factor of urea foam, resulting in ultrasonic attenuation distortion, which in turn affects the 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, summing and averaging the first relative speed and the second relative speed to obtain 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 a table lookup, 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.

[0014] Optionally, the second calculated 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 urea output concentration calculation through the ball 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 leaving 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, one of the main concepts of the present invention is to use the pyrolysis reaction to provide the value of the correction coefficient, so that the urea output concentration measured by the ball resistance tends to the actual concentration of urea in the solution. Although, under ideal conditions, urea is completely dissolved in pure water with a concentration of 32.5%, in actual operation, since urea solution is easily precipitated in a low temperature environment, urea is not completely hydrolyzed, so that there is an error in the urea output concentration calculated by the ball resistance. In order to correct the error, the present invention provides a correction coefficient by pyrolysis, so that the urea output concentration calculated by the ball resistance can be corrected to be close to its actual concentration. It is worth explaining that urea will generate gases such as ammonia and carbon dioxide during pyrolysis, and the third urea concentration can be calculated through the gas time curve.

[0023] Further, 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 attached 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, and a first valve body is arranged between the detection assembly and the sampling assembly;

[0028] A controller, wherein the controller is electrically connected to the first valve body and the detection assembly respectively;

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

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

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

[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 thermosensitive 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, the detection component and the 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 uses the pyrolysis reaction to provide the value of the correction coefficient, so that the urea output concentration measured by the ball resistance tends to the actual concentration of urea in the solution, and then the error of the urea output concentration calculated by the ball resistance is corrected, eliminating the technical problem of urea concentration measurement distortion caused by temperature and solubility problems, so that the urea concentration measurement accuracy of the present invention is higher;

[0042] 3. The present invention determines the abnormal state of the sphere through the error tolerance rate, so as to clean the sphere in time and ensure the accuracy of the measurement of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments, but those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be used as a limitation on the scope of the present invention. In addition, unless otherwise specified, the drawings are only schematically representing the composition or structure of the described objects and may contain exaggerated displays, and the drawings are not necessarily drawn to scale.

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

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

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

[0047] 1. Sampling component; 2. Detection component; 3. First valve body; 4. Controller; 5. Second valve body; 6. Pyrolysis component; 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 solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 used to limit the present invention.

[0050] The main idea of ​​the present invention is to measure the concentration of urea solution by ball 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 also Figure 1 The figure is a schematic 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 the urea solution through step S10, then obtains the first fluid resistance of the sphere in the urea solution at the first relative speed through step S20, and calculates the first measured concentration based on the first relative speed and the first fluid resistance; then obtains the second fluid resistance of the sphere in the urea solution at the second relative speed through step S30, calculates the second measured concentration based on the second relative speed and the second fluid resistance, and finally obtains the urea output concentration by summing and averaging the first relative speed and the second relative speed through step S40. In the above 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 groups of data.

[0055] For further information, see Figure 2 FIG. 1 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 sets a correction coefficient through step S41 to correct the urea output concentration. Since the concentration of the urea solution is affected by the solubility of urea crystals, although the concentration of the urea solution can be quickly measured by the spherical resistance, considering the situation that the urea solution is not completely dissolved, a correction coefficient is set to correct the urea output concentration, so as to obtain 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 understandable that during the initial operation, the correction coefficient is given in advance, and then the correction coefficient is adjusted in the subsequent measurement process, so that the use of the correction coefficient is not interfered by the pyrolysis process. It is worth explaining that since the pyrolysis reaction time is longer than the ball resistance measurement time, in order to quickly obtain the urea output concentration measured by the ball resistance, the first correction coefficient is preset at the initial stage for the operation of the system.

[0059] Optionally, the correction coefficient is summed and averaged according to multiple measurements, and the previous correction coefficient is used as the correction coefficient for obtaining the urea output concentration through the first relative speed and the second relative speed 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 calculated concentration to the average of the first calculated concentration and the second calculated concentration.

[0062] Further, 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 FIG. 1 is a schematic diagram of the structure of a detection device for urea concentration detection provided by an embodiment of the present invention.

[0066] Specifically, the present invention provides a detection device for urea concentration verification, comprising: a sampling component 1 and a detection component 2 arranged in sequence, a first valve body 3 being arranged between the detection component 2 and the sampling component 1; a controller 4, the controller 4 being 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 disposed behind the detection assembly 2, and a pyrolysis assembly 6 is disposed behind the second valve body 5; the pyrolysis assembly 6 has heating functions and gas collection functions;

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

[0069] Furthermore, the pyrolysis component 6 includes a reaction chamber 61 , a heating component, a thermistor 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, they 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 arranged on the surface of the sphere 21.

[0072] Optionally, the sampling assembly 1 includes multiple groups of sampling tubes 11 for obtaining urea solutions at different points, so that the urea output concentration measured by the present invention is reliable. It is worth noting that the present invention only takes a small amount of the urea solution already configured in the filling machine for urea concentration measurement, so it has 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 used 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, the first fluid resistance, the second relative speed and the second fluid resistance of the ball 21 are obtained by controlling the movement of the ball 21 or controlling the flow of the liquid, and the urea output concentration is obtained through the first measured concentration and the second measured concentration, so as to realize 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 by 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 pyrolysis temperature of urea, preferably above 300°C, and then after the preset pyrolysis time, the third measured concentration is calculated by the amount of gas generated, and then the correction coefficient is obtained by the third measured concentration, and the correction coefficient is uploaded to the controller 4, so that the urea output concentration can be corrected the next time the detection device calculates the urea output concentration through the detection component 2.

[0076] The present invention is described in detail above. The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the present invention and its core ideas. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these 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, 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; 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; S40, summing and averaging the first relative speed and the second relative speed to obtain urea output concentration.

2. A detection method for urea concentration determination as claimed in claim 1, characterized in that: Step S40 includes: S41, setting a correction coefficient to correct the urea output concentration.

3. A detection method for urea concentration determination as claimed in claim 2, characterized in that: The steps for obtaining the correction coefficient are as follows: S31, after step S30, heating the urea solution to a pyrolysis temperature and leaving 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.

4. A detection method for urea concentration determination as claimed in claim 3, 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.

5. A detection device for urea concentration determination, used in a detection method for urea concentration determination as claimed in any one of claims 1 to 4, characterized in that: include: A sampling component (1) and a detection component (2) are arranged in sequence, and a first valve body (3) is arranged 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) comprises a sphere (21), and the sphere (21) has a resistance detection function.

6. A detection device for urea concentration determination as claimed in claim 5, characterized in that: A second valve body (5) is arranged behind the detection component (2), and a pyrolysis component (6) is arranged 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.

7. A detection device for urea concentration determination as claimed in claim 6, characterized in that: The pyrolysis component (6) comprises a reaction chamber (61), a heating component, and a thermosensitive component; A pressure sensor disposed on the cavity wall of the reaction cavity (61) or a gas collector (62) connected to the reaction cavity (61).

8. A detection device for urea concentration determination as claimed in claim 6, 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).

9. A detection device for urea concentration determination as claimed in claim 5, characterized in that: 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).

10. 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 5 to 9.

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