Novel self-heating type quasi-blasting urea nozzle and control method

Abstract

The invention discloses a novel self-heating type quasi-blasting urea nozzle, which relates to a nozzle and comprises a shell and a nozzle main body mounted in the shell, a heating area is arranged between the nozzle main body and the shell, a urea conveying channel is arranged in the nozzle main body, a gas-liquid mixing cavity is arranged below the urea conveying channel, a gas channel is arranged between the urea conveying channel and the heating area, and the gas channel is communicated with the gas-liquid mixing cavity; the gas-liquid mixing cavity is connected with a spherical spray head through a fluid speed increasing structure, and a mixed liquid blasting sputtering spraying structure is arranged in the spherical spray head. The invention further discloses a control method of the novel self-heating type quasi-blasting urea nozzle. The covering angle and distance of urea spraying are increased, and the catalytic reduction effect is remarkably improved.

Description

Technical Field

[0001] The invention relates to a nozzle, and more particularly to a novel self-heating pseudo-explosion urea nozzle and a control method thereof. Background Art

[0002] At present, my country is constantly emphasizing high-quality and sustainable development, and has put forward the dual carbon goals of carbon peak and carbon neutrality. In order to effectively achieve these goals, automobile exhaust emission treatment technology has become a focus of development. From the perspective of automobile exhaust pollutants, automobile exhaust contains many pollutants, including HC, CO, NOX and PM particulate matter, which will cause varying degrees of damage to the environment and human body. These pollutions mainly come from diesel engines, so the focus of exhaust gas treatment is mainly on diesel engines. Among the mainstream diesel vehicle exhaust treatment technologies, my country mainly uses SCR catalytic reduction technology, and its working method is to use automotive urea solution to make automobile exhaust meet emission standards.

[0003] At present, SCR catalytic reduction technology can be mainly summarized as three parts: DOC+DPF+SCR, and each part has different functions. The DOC system is mainly responsible for converting harmful gases such as HC and CO into non-toxic and harmless substances such as CO2 and H2O. DPF is responsible for filtering out particulate matter in the exhaust gas using its physical properties, and then removing it through combustion. As the final process of exhaust gas treatment, the main function of SCR is to catalytically reduce NOX gas in the exhaust gas into non-toxic and harmless N2. Although the current exhaust gas treatment technology is relatively comprehensive, some technologies are still not mature enough. For example: problems such as urea crystallization, high exhaust gas temperature, failure to fully recover heat, and low mixing efficiency of NH3 and exhaust gas have not been well improved. And with the proposal of the dual carbon goals and the formulation of the National VI standard, it also means that there are stricter emission standards for exhaust gas. Summary of the invention

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

[0005] A novel self-heating simulated explosion urea nozzle described in the present invention comprises a shell and a nozzle body installed in the shell; a heating zone is provided between the nozzle body and the shell, 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; the gas-liquid mixing chamber is connected to a spherical nozzle through a fluid speed increasing structure, and a mixed liquid explosion sputtering injection structure is provided in the spherical nozzle.

[0006] Preferably, the mixed liquid blasting sputtering injection structure includes a solid ball and a plurality of injection holes opened on a spherical nozzle; the spherical nozzle is installed at the end of the nozzle body, the solid ball is fixed in the spherical nozzle, and a mixed flow channel is provided between the solid ball and the spherical nozzle, and between the solid ball and the fluid acceleration structure.

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

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

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

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

[0011] S1. Determine whether there is abnormal conversion in the SCR catalytic reduction technology area according to the detection result of NOx in the exhaust gas. If so, proceed to S2;

[0012] S2, collecting sensor signals of multiple NH3 sensors arranged in the mixer before the catalytic area;

[0013] S3, converting all the sensor signals into a two-dimensional plane distribution map;

[0014] S4. Iteratively process the output pressure P1 of the urea pump connected to the novel self-heating pseudo-explosive urea nozzle and the output pressure P2 of the air pump according to the two-dimensional plane distribution diagram 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 is specifically:

[0016] S41, obtaining the density of urea in the novel self-heating pseudo-explosion urea nozzle, and judging whether the urea density is sparse according to the density of the urea, if so, increasing the output pressure P1 according to the set urea pressure step and entering S42; otherwise, entering S42;

[0017] S42, obtaining the coverage range of the cross section of the exhaust pipe where the urea sprayed from the novel self-heating type pseudo-explosion urea nozzle is located, and determining whether the coverage range is the cross section of the exhaust pipe, if so, proceeding to S44; otherwise, proceeding to S43;

[0018] S43, increasing the output pressure P1 according to the urea pressure step length, and reducing the output pressure P2 according to the set gas pressure step length, and then executing S42;

[0019] S44, obtaining a detection signal of the NOx sensor, and determining whether the detection signal is equal to a set target signal. If so, 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.

[0020] Preferably, the method further comprises:

[0021] S5. The residual amount of NH3 is sensed by the array 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, constructing a three-dimensional graph corresponding to the exhaust pipe cross section through the signal of the array NH3 sensor installed in the exhaust pipe;

[0024] S52, judging whether there is a blank quadrant in the three-dimensional map, if there is a blank quadrant, detecting whether the array NH3 sensor has a fault, if there is a fault, performing fault processing and executing S53, if there is no fault, executing S53; if there is no blank quadrant, executing S56;

[0025] S53, comparing the three-dimensional graph with the exhaust pipe cross section to obtain the residual amount of NH3 in the exhaust pipe;

[0026] S54, determining whether the residual amount is less than (n-1) / n expected percentage, if so, taking the current output pressure P1 as the optimal urea output pressure; otherwise, executing S55;

[0027] S55, reducing the output pressure P1 according to the set urea pressure step, and executing S54;

[0028] S56, comparing the three-dimensional graph with the exhaust pipe cross section to obtain the residual amount of NH3 in the exhaust pipe;

[0029] S57, judging whether the residual amount is less than the expected percentage, if so, taking the current output pressure P1 as the optimal urea output pressure; otherwise, executing S58;

[0030] S58, reducing the output pressure P1 according to the set urea pressure step, and executing S57.

[0031] Preferably, in S52, detecting whether the array NH3 sensor has a fault is as follows:

[0032] The three-dimensional map is decoded by a decoder to obtain the NH3 sensor corresponding to the blank quadrant area, obtain the sensor signal of the NH3 sensor corresponding to the blank quadrant area, and determine whether there is a fault code based on the sensor signal. If so, the sensor signal of the NH3 sensor is uploaded to the central management system.

[0033] Beneficial Effects

[0034] The advantages of the present invention are:

[0035] 1. The nozzle structure design of the present invention can make urea be sprayed evenly in all directions in the exhaust pipe, improving the coverage angle and distance of urea spraying. In addition, the innovative internal design of the nozzle makes the NH 3 After being fully mixed with NOx, the catalytic reduction effect is significantly improved.

[0036] 2. Solved the crystallization problem: The spherical nozzle design enables the urea flowing through the quasi-explosion spherical nozzle to obtain a greater pressure than the traditional nozzle structure, which solves the crystallization problem of urea during transportation and is conducive to the continuous and efficient operation of the SCR system. In addition, since the crystallization problem of urea is solved, the fault code problem caused by nozzle blockage is also avoided.

[0037] 3. Since DPF technology cannot completely remove particulate matter, some small suspended particles will eventually be discharged into the atmosphere. This structural design can greatly reduce the particle size of the ejected droplets, increase the degree of contact with the particles, and then continue to accumulate, which can increase the size of the particles discharged into the atmosphere. This is not only conducive to later treatment, but also can reduce the harm after inhalation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the three-dimensional structure of the nozzle of the present invention;

[0039] Figure 2 It is a schematic diagram of a partial cross-section of the interior of the nozzle of the present invention;

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

[0041] Figure 4 It is a flow chart of the control method of the present invention;

[0042] Figure 5 A schematic diagram of conversion of the sensor signal of the present invention into a two-dimensional plane distribution diagram;

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

[0044] Figure 7 The figure is a schematic diagram of the urea current limiting design process of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0046] Embodiment 1

[0047] See also Figure 1-Figure 3 A novel self-heating pseudo-explosive urea nozzle of the present invention comprises a shell 1 and a nozzle body 2 installed in the shell 1. To ensure that urea does not crystallize in the nozzle area, a heating area 3 is provided between the nozzle body 2 and the shell 1. In terms of structural design, the outer diameter of the shell 1 gradually increases from one end close to the spherical nozzle 8 to the other end. This design enables the urea at the rear end to be heated quickly, while the larger radius at the front end can increase the heating volume, heat the urea at the front end to a certain extent, and prevent the loss of heat after heating. In terms of material, the shell 1 is a high temperature resistant and corrosion resistant metal shell, and the thermal conductive material also has the characteristics of corrosion resistance and high temperature resistance.

[0048] A urea delivery channel 4 is provided in the nozzle body 2, a gas-liquid mixing chamber 6 is provided 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. Among them, the air inlets of the urea delivery channel 4 and the gas channel 5 are both located above the nozzle body 2, and the gas-liquid mixing chamber 6 is located below the nozzle body 2, so that urea and high-pressure gas can be mixed in the gas-liquid mixing chamber 6 in a forward direction. In addition, the air inlet and the air outlet of the gas channel 5 are respectively located on both sides of the urea delivery channel 4, which is conducive to buffering the air pressure and improving the stability of the air pressure.

[0049] The gas-liquid mixing chamber 6 is connected to a spherical nozzle 8 through a fluid speed increasing structure 7. The fluid speed increasing structure 7 is a venturi tube structure, which includes an inlet section, a contraction section, a throat, and a diffusion section. Such a structure can make the mixing effect of gas and urea more significant by reducing the cross section and generating negative pressure, and the acceleration effect brought about can also make the urea have a wider range after being sprayed out of the nozzle.

[0050] The spherical nozzle 8 is provided with a mixed liquid explosion sputtering injection structure, which can make urea under high pressure and be sprayed into the exhaust pipe in the form of explosion sputtering. The spherical nozzle 8 is a high temperature resistant and corrosion resistant metal. The mixed liquid explosion sputtering injection structure includes a solid ball 10 and a plurality of injection holes 9 provided on the spherical nozzle 8. The spherical nozzle 8 is installed at the end of the nozzle body 2, and the solid ball 10 is fixed in the spherical nozzle 8, and a mixed flow channel 12 is provided between the solid ball 10 and the spherical nozzle 8, and a diversion chamber 11 is provided between the solid ball 10 and the fluid speed increasing structure 7. The design of the solid ball 10 firstly ensures that the structure has sufficient strength, and secondly, a narrow flow space is formed between the metal shell and the central entity, which ensures the all-round release and pressure release of urea.

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

[0052] 6NO 2 +4NH 3 +6NO=7N 2 +12H 2 O.

[0053] Embodiment 2

[0054] like Figure 4-7 As shown, a control method is used to control a new self-heating type pseudo-explosion urea nozzle to spray. The method specifically includes the following steps:

[0055] S1, the 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 it is determined whether there is an abnormal conversion condition in the SCR catalytic reduction technology area based on the detection result of NOx in the exhaust gas. If so, an abnormal signal is generated and sent to the control module, and S2 is performed.

[0056] S2, arrange several NH in the mixer before the catalytic area 3 Sensor, sensor for NH 3 The distribution of the mixed mixture is tested and recorded. 3 The content is reflected in the size of the sensor signal, and the sensor signal is sent to the control module.

[0057] S3, the control module mixes several NH 3 The sensing signal emitted by the sensor is converted into a two-dimensional plane distribution map of the corresponding position, and effective information is extracted. Similar to the conventional signal processing method, the electrical signal I is first obtained through pre-processing such as filtering and denoising. 1 ,I 2 ,I 3..., then map, interpolate corresponding positions and generate smooth data, and finally use OpenCV, PIL, etc. to realize image rendering. The conversion diagram is as follows Figure 5 Shown

[0058] S4. Iteratively process the output pressure P1 of the urea pump connected to the novel self-heating pseudo-explosion urea nozzle and the output pressure P2 of the air pump according to the two-dimensional plane distribution diagram 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] The increase in urea pressure is reflected in the increase in sputtering distance and NH 3 The more concentrated distribution of the gas pressure reflects the increase in the sputtering distance and the NH 3 The distribution is more sparse, and the mixing ratio is mainly reflected in the density. To simplify the control process, the control idea is: first, according to the density of urea, control the mixing ratio of urea pressure P1 and air pressure P2 i=P1 / P2. Under the premise of ensuring that the mixing ratio i remains unchanged, adjust the pressure to increase the coverage to the cross-sectional area. At this time, if the nitrogen oxide sensor signal is strong, it can be reflected in the density rather than the coverage. The control flow chart is shown below Figure 6 :

[0060] S41, obtaining the density of urea in the novel self-heating pseudo-explosion urea nozzle, and judging whether the urea density is sparse according to the density of urea, if so, increasing the output pressure P1 according to the set urea pressure step and entering S42; otherwise, entering S42.

[0061] S42, obtaining the coverage range of the cross section of the exhaust pipe where the urea sprayed from the novel self-heating pseudo-explosive urea nozzle is located, and determining whether the coverage range is the cross section of the exhaust pipe. If so, proceed to S44; otherwise, proceed to S43.

[0062] S43, increasing the output pressure P1 according to the urea pressure step length, and reducing the output pressure P2 according to the set gas pressure step length, and then executing S42.

[0063] S44, obtaining the detection signal of the NOx sensor, and determining whether the detection signal is equal to the set target signal. If so, 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.

[0064] Since urea produces NH 3 The reaction cannot be completed and there will be residual NH 3If the release amount is too much, it will also cause waste, urea sticking to the inner wall of the exhaust pipe, affecting the detection effect of the NOx sensor, etc. Therefore, the control invention of the present invention also includes S5, through the array type NH installed in the exhaust pipe 3 Sensors to sense NH 3 The urea release pressure of the new self-heating quasi-explosion urea nozzle is adjusted according to the residual amount and the set expected percentage, thereby ensuring cost savings and reducing NH 3 Impact on the accuracy of NOx sensors.

[0065] Considering that different brands of cars have different exhaust pipe structures and different sizes of exhaust pipes, it is necessary to detect the residual NH at the end of the exhaust pipe. 3 The present invention improves the working conditions by installing n array-type NH 3 Sensor to sense residual NH 3 , using intelligent algorithms to compare and analyze the three-dimensional graph with the exhaust pipe cross section, the residual volume at the edge of the cross section should not exceed the expected percentage. Finally, the comparison results are used to adjust the urea release pressure. In addition, due to the NH 3 The content is too low, or even 0 under ideal control, which can be easily confused with sensor failure. 3 A decoder is designed between the electronic control unit ECU to detect the fault code to determine whether the sensor is faulty. The control flow chart is as follows Figure 7 As shown:

[0066] S51, through the array NH installed in the exhaust pipe 3 The sensor's signals form a three-dimensional graph that corresponds to the exhaust pipe cross section.

[0067] S52, determine whether there is a blank quadrant area in the three-dimensional map. If there is a blank quadrant area, detect whether the array NH3 sensor has a fault. If there is a fault, perform fault processing and execute S53. If there is no fault, execute S53; if there is no blank quadrant area, execute S56.

[0068] The three-dimensional map is decoded by a decoder to obtain the NH3 sensor corresponding to the blank quadrant area, obtain the sensor signal of the NH3 sensor corresponding to the blank quadrant area, and determine whether there is a fault code based on the sensor signal. If there is, the sensor signal of the NH3 sensor is uploaded to the central management system.

[0069] S53, compare the three-dimensional image with the exhaust pipe cross section to obtain the NH 3 of residual amount.

[0070] S54, determining whether the residual amount is less than (n-1) / n expected percentage, if so, taking the current output pressure P1 as the optimal urea output pressure; otherwise, executing S55.

[0071] S55, reducing the output pressure P1 according to the set urea pressure step, and executing S54.

[0072] S56. Compare the three-dimensional image with the exhaust pipe cross section to obtain the NH 3 of residual amount.

[0073] S57, determining whether the residual amount is less than the expected percentage, if so, taking the current output pressure P1 as the optimal urea output pressure; otherwise, executing S58.

[0074] S58, reducing the output pressure P1 according to the set urea pressure step, and executing S57.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A new self-heating quasi-explosion urea nozzle, characterized in that: The invention comprises a shell (1) and a nozzle body (2) installed in the shell (1); a heating zone (3) is provided between the nozzle body (2) and the shell (1); a urea delivery channel (4) is provided in the nozzle body (2); a gas-liquid mixing chamber (6) is provided below the urea delivery channel (4); a gas channel (5) is provided between the urea delivery channel (4) and the heating zone (3); the gas channel (5) is connected to the gas-liquid mixing chamber (6); the gas-liquid mixing chamber (6) is connected to a spherical nozzle (8) via a fluid speed increasing structure (7); a mixed liquid blasting and sputtering injection structure is provided in the spherical nozzle (8).

2. A novel self-heating pseudo-explosion urea nozzle according to claim 1, characterized in that: The mixed liquid blasting sputtering injection structure comprises a solid ball (10) and a plurality of injection holes (9) provided on a spherical nozzle (8); the spherical nozzle (8) is installed at the end of a nozzle body (2), the solid ball (10) is fixed in the spherical nozzle (8), and a mixed liquid flow channel (12) is provided between the solid ball (10) and the spherical nozzle (8), and between the solid ball (10) and the fluid speed increasing structure (7).

3. The novel self-heating pseudo-explosion urea nozzle according to claim 1 is characterized in that: The outer diameter of the housing (1) gradually increases from one end close to the spherical nozzle (8) to the other end.

4. The novel self-heating pseudo-explosion urea nozzle according to claim 1 is characterized in that: The fluid speed increasing structure (7) is a Venturi tube structure.

5. The novel self-heating pseudo-explosion urea nozzle according to claim 1 is characterized in that: The air inlet and the air outlet of the gas channel (5) are respectively located on both sides of the urea delivery channel (4).

6. A control method for the novel self-heating pseudo-explosion urea nozzle according to any one of claims 1 to 5, characterized in that: The method includes: S1. Determine whether there is abnormal conversion in the SCR catalytic reduction technology area according to the detection result of NOx in the exhaust gas. If so, proceed to S2; S2, collecting sensor signals of multiple NH3 sensors arranged in the mixer before the catalytic area; S3, converting all the sensor signals into a two-dimensional plane distribution map; S4. Iteratively process the output pressure P1 of the urea pump connected to the novel self-heating pseudo-explosive urea nozzle and the output pressure P2 of the air pump according to the two-dimensional plane distribution diagram to obtain the optimal urea output pressure of the urea pump and the optimal gas output pressure of the air pump.

7. The control method according to claim 6, characterized in that: In S4, the iterative process is specifically as follows: S41, obtaining the density of urea in the novel self-heating pseudo-explosion urea nozzle, and judging whether the urea density is sparse according to the density of the urea, if so, increasing the output pressure P1 according to the set urea pressure step and entering S42; otherwise, entering S42; S42, obtaining the coverage range of the cross section of the exhaust pipe where the urea sprayed from the novel self-heating type pseudo-explosion urea nozzle is located, and determining whether the coverage range is the cross section of the exhaust pipe, if so, proceeding to S44; otherwise, proceeding to S43; S43, increasing the output pressure P1 according to the urea pressure step length, and reducing the output pressure P2 according to the set gas pressure step length, and then executing S42; S44, obtaining a detection signal of the NOx sensor, and determining whether the detection signal is equal to a set target signal. If so, 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.

8. The control method according to claim 6, characterized in that: The method further includes: S5. The residual amount of NH3 is sensed by the array 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.

9. The control method according to claim 8, characterized in that: S5 specifically includes: S51, constructing a three-dimensional graph corresponding to the exhaust pipe cross section through the signal of the array NH3 sensor installed in the exhaust pipe; S52, judging whether there is a blank quadrant in the three-dimensional map, if there is a blank quadrant, detecting whether the array NH3 sensor has a fault, if there is a fault, performing fault processing and executing S53, if there is no fault, executing S53; if there is no blank quadrant, executing 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, determining whether the residual amount is less than (n-1) / n expected percentage, if so, taking the current output pressure P1 as the optimal urea output pressure; otherwise, executing S55; S55, reducing the output pressure P1 according to the set urea pressure step, and executing 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 so, taking the current output pressure P1 as the optimal urea output pressure; otherwise, executing S58; S58, reducing the output pressure P1 according to the set urea pressure step, and executing S57.

10. The control method according to claim 9, characterized in that: In S52, detecting whether the array NH3 sensor has a fault is as follows: The three-dimensional map is decoded by a decoder to obtain the NH3 sensor corresponding to the blank quadrant area, obtain the sensor signal of the NH3 sensor corresponding to the blank quadrant area, and determine whether there is a fault code based on the sensor signal. If so, the sensor signal of the NH3 sensor is uploaded to the central management system.

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