A novel self-heating, explosion-prone urea nozzle and its control method

Abstract

This invention discloses a novel self-heating, pseudo-explosive urea nozzle, comprising a housing and a nozzle body installed within the housing. A heating zone is provided between the nozzle body and the housing. A urea delivery channel is provided within the nozzle body, and a gas-liquid mixing chamber is located below the urea delivery channel. A gas channel is provided between the urea delivery channel and the heating zone, and the gas channel communicates with the gas-liquid mixing chamber. A spherical nozzle is connected to the gas-liquid mixing chamber via a fluid acceleration structure, and the spherical nozzle contains a mixture explosion sputtering spray structure. This invention also discloses a control method for the novel self-heating, pseudo-explosive urea nozzle. This invention improves the coverage angle and distance of urea injection, significantly enhancing the catalytic reduction effect.

Description

Technical Field

[0001] This invention relates to nozzles, and more specifically, to a novel self-heating, quasi-explosive urea nozzle and its control method. Background Technology

[0002] Currently, my country is increasingly emphasizing high-quality and sustainable development, and has proposed dual carbon goals of carbon peaking and carbon neutrality. To effectively achieve these goals, automotive exhaust emission treatment technology has become a key area of ​​development. Looking at automotive exhaust pollutants, they contain numerous substances, including HC, CO, NOx, and PM particulate matter, all of which cause varying degrees of damage to the environment and human health. These pollutants primarily originate from diesel engines; therefore, the focus of exhaust emission treatment is mainly on diesel engines. Among mainstream diesel vehicle exhaust treatment technologies, my country primarily uses SCR catalytic reduction technology, which utilizes automotive urea solution to meet emission standards for vehicle exhaust.

[0003] Currently, SCR (Self-Catalytic Reduction) technology can be mainly summarized into three parts: DOC (Discharge Oxide), DPF (Discharge Power Factor), and SCR, each with a different function. The DOC system is primarily responsible for converting harmful gases like HC and CO into non-toxic substances such as CO2 and H2O. DPF is responsible for filtering particulate matter from the exhaust gas using physical properties, which is then removed through combustion. SCR, as the final stage of exhaust gas treatment, mainly functions to catalytically reduce NOx in the exhaust gas into non-toxic N2. While current exhaust gas treatment technologies are relatively comprehensive, some technologies remain immature. For example, issues such as urea crystallization, high exhaust gas temperatures with insufficient heat recovery, and low mixing efficiency of NH3 and exhaust gas have not been effectively addressed. Furthermore, the introduction of dual-carbon targets and the formulation of the China VI emission standard mean stricter emission standards for exhaust gases. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a novel self-heating pseudo-explosive urea nozzle and control method to address the shortcomings of the prior art, thereby improving the urea injection effect and increasing the catalytic reduction rate.

[0005] The present invention discloses a novel self-heating pseudo-explosive urea nozzle, comprising a housing and a nozzle body installed within the housing; a heating zone is provided between the nozzle body and the housing, a urea delivery channel is provided in the nozzle body, a gas-liquid mixing chamber is provided below the urea delivery channel, a gas channel is provided between the urea delivery channel and the heating zone, and the gas channel is connected to the gas-liquid mixing chamber; a spherical nozzle is connected to the gas-liquid mixing chamber through a fluid acceleration structure, and the spherical nozzle is provided with a mixed liquid explosion sputtering spray structure.

[0006] Preferably, the mixed liquid explosion sputtering jet structure includes a solid sphere and a plurality of jet holes opened on the spherical nozzle; the spherical nozzle is installed at the end of the nozzle body, the solid sphere is fixed in the spherical nozzle, and a mixing airflow channel is provided between the solid sphere and the spherical nozzle, and between the solid sphere and the fluid acceleration structure.

[0007] Preferably, the outer diameter of the outer casing gradually increases from one end near the spherical nozzle to the other end.

[0008] Preferably, the fluid speed-increasing structure is a Venturi tube structure.

[0009] Preferably, the gas inlet and outlet of the gas channel are located on both sides of the urea delivery channel.

[0010] A control method for a novel self-heating pseudo-explosive urea nozzle as described above, the method comprising:

[0011] S1. Determine whether there is an abnormal conversion condition in the SCR catalytic reduction technology area based on the detection results of NOx in the exhaust gas. If so, proceed to S2.

[0012] S2. Collect the sensing signals from multiple NH3 sensors arranged in the mixer before the catalytic zone;

[0013] S3. Convert all the aforementioned sensing signals into a two-dimensional planar distribution map;

[0014] S4. Based on the two-dimensional planar distribution diagram, iteratively process the output pressure P1 of the urea pump and the output pressure P2 of the air pump connected to the novel self-heating pseudo-explosive urea nozzle to obtain the optimal urea output pressure of the urea pump and the optimal gas output pressure of the air pump.

[0015] Preferably, in S4, the iterative process specifically includes:

[0016] S41. Obtain the density of urea in the novel self-heating pseudo-explosive urea nozzle, and determine whether the urea density is sparse based on the urea density. If so, increase the output pressure P1 according to the set urea pressure step and proceed to S42; otherwise, proceed to S42.

[0017] S42. Obtain the coverage area of ​​the urea sprayed from the novel self-heating pseudo-explosive urea nozzle in the cross section of the exhaust pipe, and determine whether the coverage area is the cross section of the exhaust pipe. If yes, proceed to S44; otherwise, proceed to S43.

[0018] S43. Increase the output pressure P1 according to the urea pressure step size, and decrease the output pressure P2 according to the set air pressure step size, and then execute S42.

[0019] S44. Obtain the detection signal from the NOx sensor and determine whether the detection signal is equal to the set target signal. If so, take the current output pressure P1 as the optimal urea output pressure and the current output pressure P2 as the optimal gas output pressure.

[0020] Preferably, the method further includes:

[0021] S5. The residual amount of NH3 is sensed by an array-type NH3 sensor installed in the exhaust pipe, and the urea release pressure of the novel self-heating pseudo-explosive urea nozzle is adjusted according to the residual amount and the set expected percentage.

[0022] Preferably, S5 specifically includes:

[0023] S51. Construct a three-dimensional diagram corresponding to the cross-section of the exhaust pipe using the signal from the array-type NH3 sensor installed in the exhaust pipe;

[0024] S52. Determine whether there is a blank quadrant region in the three-dimensional image. If there is a blank quadrant region, check whether there is a fault in the array-type NH3 sensor. If there is a fault, perform fault handling and then execute S53. If there is no fault, execute S53. If there is no blank quadrant region, execute S56.

[0025] S53. Compare the three-dimensional diagram with the exhaust pipe cross-section to obtain the residual amount of NH3 in the exhaust pipe;

[0026] S54. Determine whether the residual amount is less than (n-1) / n expected percentage. If so, take the current output pressure P1 as the optimal urea output pressure; otherwise, proceed to S55.

[0027] S55. Reduce the output pressure P1 according to the set urea pressure step size, and execute S54;

[0028] S56. Compare the three-dimensional diagram with the exhaust pipe cross-section to obtain the residual amount of NH3 in the exhaust pipe;

[0029] S57. Determine whether the residual amount is less than the expected percentage. If so, use the current output pressure P1 as the optimal urea output pressure; otherwise, proceed to S58.

[0030] S58. Reduce the output pressure P1 according to the set urea pressure step size, and execute S57.

[0031] Preferably, in S52, detecting whether the array-type NH3 sensor is faulty is as follows:

[0032] The 3D image is decoded by a decoder to obtain the NH3 sensor corresponding to the blank quadrant area, obtain the sensing signal of the NH3 sensor corresponding to the blank quadrant area, and determine whether there is a fault code based on the sensing signal. If there is, the sensing signal of the NH3 sensor is uploaded to the central management system.

[0033] Beneficial effects

[0034] The advantages of this invention are:

[0035] 1. The nozzle structure design of this invention enables urea to be uniformly sprayed in all directions within the exhaust pipe, improving the coverage angle and distance of urea injection. Furthermore, the innovative internal design of the nozzle allows for thorough mixing of NH3 and NOx released from urea decomposition, significantly enhancing the catalytic reduction effect.

[0036] 2. Solved the crystallization problem: The spherical nozzle design allows urea flowing through the simulated explosion spherical nozzle to receive greater pressure compared to traditional nozzle structures. This solves the crystallization problem that occurs during urea transportation, which is beneficial for the continuous and efficient operation of the SCR system. Furthermore, since the urea crystallization problem has been resolved, fault code issues caused by nozzle blockage are also avoided.

[0037] 3. Because DPF technology cannot completely remove particulate matter, some small suspended particles will eventually be released into the atmosphere. This structural design significantly reduces the size of the sprayed droplets, increasing contact with particulate matter. Through continuous accumulation, this increases the size of the particulate matter released into the atmosphere. This not only facilitates subsequent treatment but also reduces the harm caused by inhalation. Attached Figure Description

[0038] Figure 1 This is a three-dimensional structural diagram of the nozzle of the present invention;

[0039] Figure 2 This is a partial cross-sectional view of the nozzle interior of the present invention;

[0040] Figure 3 This is a schematic diagram of the connection structure between the spherical nozzle and the fluid acceleration structure of the present invention;

[0041] Figure 4 This is a schematic diagram of the control method of the present invention;

[0042] Figure 5 This is a schematic diagram illustrating the conversion of the sensing signal into a two-dimensional planar distribution map according to the present invention;

[0043] Figure 6 This is a schematic diagram of the iterative processing flow of the present invention;

[0044] Figure 7 This is a schematic diagram of the urea flow restriction design process of the present invention. Detailed Implementation

[0045] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0046] Example 1

[0047] See Figures 1-3 This invention discloses a novel self-heating, pseudo-explosive urea nozzle, comprising a housing 1 and a nozzle body 2 installed within the housing 1. To ensure that urea does not crystallize in the nozzle area, a heating zone 3 is provided between the nozzle body 2 and the housing 1. Structurally, the outer diameter of the housing 1 gradually increases from one end near the spherical nozzle 8 to the other. This design allows for rapid heating of the urea at the rear end, while the larger radius at the front end increases the heating volume, enabling a certain degree of heating of the urea at the front end and preventing heat loss after heating. In terms of materials, the housing 1 is a high-temperature resistant and corrosion-resistant metal shell, and the thermally conductive material also possesses corrosion resistance and high-temperature resistance characteristics.

[0048] The nozzle body 2 is equipped with a urea delivery channel 4, and a gas-liquid mixing chamber 6 is located below the urea delivery channel 4. A gas channel 5 is provided between the urea delivery channel 4 and the heating zone 3, and the gas channel 5 is connected to the gas-liquid mixing chamber 6. The inlets of both the urea delivery channel 4 and the gas channel 5 are located above the nozzle body 2, while the gas-liquid mixing chamber 6 is located below the nozzle body 2. This allows urea and high-pressure gas to mix in the gas-liquid mixing chamber 6 in a forward direction. Furthermore, the inlet and outlet of the gas channel 5 are located on opposite sides of the urea delivery channel 4, which helps to buffer the gas pressure and improve its stability.

[0049] The gas-liquid mixing chamber 6 is connected to a spherical nozzle 8 via a fluid acceleration structure 7. The fluid acceleration structure 7 is a Venturi tube structure, comprising an inlet section, a constriction section, a throat, and a diffuser section. This structure, by utilizing the reduced cross-section and the generation of negative pressure, significantly enhances the mixing effect of the gas and urea, and the resulting acceleration allows the urea to travel a wider range after exiting the nozzle.

[0050] The spherical nozzle 8 incorporates a mixed liquid explosive sputtering spray structure, which allows urea to be sprayed into the exhaust pipe under high pressure in an explosive sputtering manner. The spherical nozzle 8 is made of a high-temperature resistant and corrosion-resistant metal. The mixed liquid explosive sputtering spray structure includes a solid sphere 10 and multiple spray holes 9 formed on the spherical nozzle 8. The spherical nozzle 8 is installed at the end of the nozzle body 2, and the solid sphere 10 is fixed inside the spherical nozzle 8. A mixing airflow channel 12 is provided between the solid sphere 10 and the spherical nozzle 8, and a flow divider 11 is provided between the solid sphere 10 and the fluid acceleration structure 7. The design of the solid sphere 10 ensures sufficient structural strength and creates a narrow flow space between the metal outer shell and the central solid, guaranteeing the all-round release of urea and the release pressure.

[0051] Subsequently, in the exhaust pipe, under the SCR catalytic reduction technology, the following comprehensive chemical reactions will occur:

[0052] 6NO2 + 4NH3 + 6NO = 7N2 + 12H2O.

[0053] Example 2

[0054] like Figure 4-7 As shown, a control method is used to control the injection of a novel self-heating, pseudo-explosive urea nozzle. The method specifically includes the following steps:

[0055] S1, NO in the exhaust gas is detected by the nitrogen oxide sensor at the end of the exhaust pipe. X The components are detected, and the SCR catalytic reduction technology area is judged to have any abnormal conversion based on the detection results of NOx in the exhaust gas. If so, an abnormality signal is generated and sent to the control module, and S2 is performed.

[0056] S2. Several NH3 sensors are arranged in the mixer before the catalytic zone. The sensors detect and record the distribution of NH3 after mixing. The NH3 content is reflected in the magnitude of the sensing signal, which is then sent to the control module.

[0057] S3, the control module converts the sensing signals emitted by several NH3 sensors in the mixer into a two-dimensional planar distribution map of the corresponding locations and extracts the effective information. Similar to conventional signal processing methods, it first obtains electrical signals I1, I2, I3... through preprocessing such as filtering and denoising, then maps and interpolates the corresponding positions to generate smooth data, and finally uses OpenCV, PIL, etc. to implement image rendering. A simplified diagram of the conversion is shown below. Figure 5 As shown

[0058] S4. Based on the two-dimensional planar distribution diagram, the output pressure P1 of the urea pump and the output pressure P2 of the air pump connected to the new self-heating pseudo-explosive urea nozzle are iteratively processed to obtain the optimal urea output pressure of the urea pump and the optimal gas output pressure of the air pump, so that the urea and the exhaust gas can have the best mixing effect.

[0059] An increase in urea pressure reflects an increase in sputtering distance and a more concentrated distribution of NH3, while an increase in gas pressure reflects an increase in sputtering distance and a sparser distribution of NH3. The mixing ratio mainly reflects the density. To simplify the control process, the control strategy is as follows: First, based on the density of urea, control the mixing ratio i = P1 / P2 between urea pressure P1 and gas pressure P2. While keeping the mixing ratio i constant, adjust the pressure to increase the coverage area to the cross-sectional area. If the nitrogen and oxygen sensor signal is strong at this point, it will reflect the density rather than the coverage area. The control flowchart is shown below. Figure 6 :

[0060] S41. Obtain the density of urea in the new self-heating pseudo-explosive urea nozzle, and determine whether the urea density is sparse based on the urea density. If so, increase the output pressure P1 according to the set urea pressure step and proceed to S42; otherwise, proceed to S42.

[0061] S42. Obtain the coverage area of ​​the urea sprayed from the new self-heating pseudo-explosive urea nozzle in the cross section of the exhaust pipe, and determine whether the coverage area is the cross section of the exhaust pipe. If so, proceed to S44; otherwise, proceed to S43.

[0062] S43. Increase the output pressure P1 according to the urea pressure step size, and at the same time decrease the output pressure P2 according to the set air pressure step size, and then execute S42.

[0063] S44. Obtain the detection signal from the NOx sensor and determine whether the detection signal is equal to the set target signal. If so, use the current output pressure P1 as the optimal urea output pressure and the current output pressure P2 as the optimal gas output pressure.

[0064] Because the NH3 produced after urea atomization cannot react completely, residual NH3 will remain. Excessive release can lead to waste, urea sticking to the inner wall of the exhaust pipe, and affecting the detection performance of the NOx sensor. Therefore, the control method of this invention also includes S5: sensing the residual amount of NH3 using an array-type NH3 sensor installed in the exhaust pipe, and adjusting the urea release pressure of the novel self-heating, pseudo-explosive urea nozzle according to the residual amount and a set expected percentage, thereby ensuring cost savings and reducing the impact of NH3 on the accuracy of the nitrogen oxide sensor.

[0065] Considering the differences in exhaust pipe structure and varying front and rear dimensions among different car brands, it is necessary to detect the residual NH3 content at the end of the exhaust pipe to improve operating conditions. This invention uses an array of n NH3 sensors installed at the tail of the exhaust pipe to detect residual NH3. An intelligent algorithm compares the 3D image with the exhaust pipe cross-section, ensuring the residual amount at the cross-section edge does not exceed the expected percentage. The comparison results are then used to adjust the urea release pressure. Furthermore, since the NH3 content in the treated exhaust gas is often low, even zero under ideal control, it can easily be confused with sensor malfunctions. Therefore, a decoder is designed between several NH3 sensors and the Electronic Control Unit (ECU) to detect fault codes and determine if a sensor malfunction has occurred. The control flowchart is as follows: Figure 7 As shown:

[0066] S51. Construct a three-dimensional diagram corresponding to the cross-section of the exhaust pipe using the signal from the array-type NH3 sensor installed in the exhaust pipe.

[0067] S52. Determine whether there is a blank quadrant region in the 3D image. If there is a blank quadrant region, check whether there is a fault in the array-type NH3 sensor. If there is a fault, perform fault handling and then execute S53. If there is no fault, execute S53. If there is no blank quadrant region, execute S56.

[0068] Specifically, the 3D image is decoded using a decoder to obtain the NH3 sensor corresponding to the blank quadrant area. The sensing signal of the NH3 sensor corresponding to the blank quadrant area is obtained, and the presence of a fault code is determined based on the sensing signal. If a fault code is found, the sensing signal of the NH3 sensor is uploaded to the central management system.

[0069] S53. Compare the three-dimensional diagram with the exhaust pipe cross-section to obtain the residual amount of NH3 in the exhaust pipe.

[0070] S54. Determine if the residual amount is less than (n-1) / n of the expected percentage. If so, use the current output pressure P1 as the optimal urea output pressure; otherwise, proceed to S55.

[0071] S55. Reduce the output pressure P1 according to the set urea pressure step size, and execute S54.

[0072] S56. Compare the 3D diagram with the exhaust pipe cross-section to obtain the residual amount of NH3 in the exhaust pipe.

[0073] S57. Determine if the residual amount is less than the expected percentage. If so, use the current output pressure P1 as the optimal urea output pressure; otherwise, execute S58.

[0074] S58. Reduce the output pressure P1 according to the set urea pressure step size, and execute S57.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A novel self-heatable pseudo-explosive urea nozzle characterized in that, The application relates to a new type of self-heating type pseudo-explosion urea nozzle, which comprises an outer shell (1) and a nozzle body (2) installed in the outer shell (1); a heating area (3) is arranged between the nozzle body (2) and the outer shell (1); a urea conveying channel (4) is arranged in the nozzle body (2); a gas-liquid mixing cavity (6) is arranged below the urea conveying channel (4); a gas channel (5) is arranged between the urea conveying channel (4) and the heating area (3); the gas channel (5) is communicated with the gas-liquid mixing cavity (6); the gas-liquid mixing cavity (6) is connected with a spherical nozzle head (8) through a fluid speed increasing structure (7); and a mixed liquid explosion splashing and spraying structure is arranged in the spherical nozzle head (8). The mixed liquid explosion splashing and spraying structure comprises a solid ball (10) and a plurality of spraying holes (9) arranged on the spherical nozzle head (8); the spherical nozzle head (8) is arranged at the end of the nozzle body (2); the solid ball (10) is fixed in the spherical nozzle head (8) and is arranged between the solid ball (10) and the spherical nozzle head (8); and a mixed gas flow channel (12) is arranged between the solid ball (10) and the fluid speed increasing structure (7). The outer diameter of the outer shell (1) gradually increases from one end close to the spherical nozzle head (8) to the other end.

2. A novel self-heatable pseudo-explosive urea nozzle according to claim 1, characterized in that, The fluid speed increasing structure (7) is a Venturi tube structure.

3. A novel self-heatable pseudo-explosive urea nozzle as claimed in claim 1, wherein, The gas inlet and the gas outlet of the gas channel (5) are respectively arranged on the two sides of the urea conveying channel (4).

4. A method of controlling a new self-heatable pseudo-explosive urea nozzle according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: S1, judging whether an abnormal conversion condition exists in an SCR catalytic reduction technology region according to a detection result of NOx in tail gas; if yes, performing S2; S2, collecting sensing signals of a plurality of NH3 sensors arranged in a mixer before a catalytic region; S3, converting all the sensing signals into a two-dimensional plane distribution map; S4, performing iterative processing on output pressure P1 of a urea pump and output pressure P2 of a gas pump connected with the new type of self-heating type pseudo-explosion urea nozzle according to the two-dimensional plane distribution map, so as to obtain optimal urea output pressure of the urea pump and optimal gas output pressure of the gas pump.

5. The control method according to claim 4, characterized by In S4, the iterative processing is specifically as follows: S41, obtaining the density of urea in the new type of self-heating type pseudo-explosion urea nozzle, and judging whether the urea density is sparse according to the density of the urea; if yes, increasing the output pressure P1 according to a set urea pressure step and entering S42; otherwise, entering S42; S42, obtaining a coverage range of urea sprayed from the new type of self-heating type pseudo-explosion urea nozzle in a cross section of an exhaust pipe, and judging whether the coverage range is the cross section of the exhaust pipe; if yes, entering S44; otherwise, entering S43; S43, increasing the output pressure P1 according to the urea pressure step, and decreasing the output pressure P2 according to a set gas pressure step, and then performing S42; S44, obtaining a detection signal of a NOx sensor, and judging whether the detection signal is equal to a set target signal; if yes, taking the current output pressure P1 as the optimal urea output pressure and taking the current output pressure P2 as the optimal gas output pressure.

6. The control method according to claim 5, characterized by The method further comprises the following steps: S5, sensing the residual amount of NH3 by the arrayed NH3 sensor installed in the exhaust pipe, and adjusting the urea release pressure of the new self-heating type pseudo-explosion urea nozzle according to the residual amount and the set expected percentage.

7. The control method according to claim 6, characterized by S5 specifically comprises: S51, constructing a three-dimensional graph corresponding to the exhaust pipe cross section by the signal of the arrayed NH3 sensor installed in the exhaust pipe; S52, judging whether there is a blank quadrant area in the three-dimensional graph, if there is the blank quadrant area, detecting whether there is a fault in the arrayed NH3 sensor, if there is a fault, performing S53 after fault handling, if there is no fault, performing S53; if there is no blank quadrant area, performing S56; S53, comparing the three-dimensional graph with the exhaust pipe cross section to obtain the residual amount of NH3 in the exhaust pipe; S54, judging whether the residual amount is less than the (n-1) / n expected percentage, if yes, taking the current output pressure P1 as the best urea output pressure; otherwise, performing S55; S55, reducing the output pressure P1 according to the set urea pressure step, and performing S54; S56, comparing the three-dimensional graph with the exhaust pipe cross section to obtain the residual amount of NH3 in the exhaust pipe; S57, judging whether the residual amount is less than the expected percentage, if yes, taking the current output pressure P1 as the best urea output pressure; otherwise, performing S58; S58, reducing the output pressure P1 according to the set urea pressure step, and performing S57.

8. The control method according to claim 7, characterized by, In S52, detecting whether there is a fault in the arrayed NH3 sensor is: decoding the three-dimensional graph by a decoder to obtain the NH3 sensor corresponding to the blank quadrant area, obtaining the sensing signal of the NH3 sensor corresponding to the blank quadrant area, and judging whether there is a fault code according to the sensing signal, if there is, uploading the sensing signal of the NH3 sensor to a central management system.

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