Method and system for preventing crystallization of urea nozzle

Abstract

The invention provides a method and system for preventing crystallization of a urea nozzle, the method is suitable for the control field, and the method comprises the steps that when a vehicle is started, a specified device is heated to dissolve urea crystals of the urea nozzle of the vehicle, the specified device is installed at the position of the urea nozzle, and the specified device is provided with a plurality of air holes; identifying a currently enabled operating mode of an engine of the vehicle; and according to a control strategy matched with the currently-started operation mode of the engine, the high-pressure gas is discharged from a gas hole of the designated device so as to be used for cleaning urea residual liquid of the urea nozzle. According to the scheme, urea crystals of the urea nozzle are dissolved by heating the designated device installed at the nozzle of the urea nozzle, and urea residual liquid of the urea nozzle is cleaned by discharging high-pressure gas from the air hole of the designated device, so that urea crystals around the urea nozzle are avoided.

Description

Technical Field

[0001] The invention relates to the field of control technology, and in particular to a method and a system for preventing a urea nozzle from crystallizing. Background Art

[0002] The use of urea is the main measure to reduce nitrogen oxide (NOx) emissions, which can ensure that vehicles meet emission standards. However, in the actual use of urea, abnormal crystallization of urea nozzles is prone to occur. For example, the atomized urea falls near the urea nozzle, causing urea accumulation and crystallization, which will affect the normal injection of urea and cause abnormal emissions.

[0003] Therefore, there is an urgent need for a method that can prevent urea nozzles from crystallizing. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a method and system for preventing a urea nozzle from crystallizing, so as to prevent the urea nozzle from crystallizing.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A first aspect of an embodiment of the present invention discloses a method for preventing a urea nozzle from crystallizing, the method comprising:

[0007] When the vehicle is started, the designated device is heated to dissolve urea crystals of the urea nozzle of the vehicle, the designated device is installed at the nozzle of the urea nozzle, and the designated device is provided with a plurality of air holes;

[0008] identifying a currently enabled operating mode of an engine of the vehicle;

[0009] According to a control strategy matching the currently enabled operating mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the residual urea of ​​the urea nozzle, wherein the direction in which the high-pressure gas is discharged from the air hole of the designated device is the same as the direction in which the urea nozzle sprays urea.

[0010] Preferably, the currently enabled operating mode of the engine is a regeneration mode;

[0011] According to a control strategy matching the currently enabled operation mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the urea residual liquid of the urea nozzle, including:

[0012] Obtaining a first purge frequency of the high pressure gas;

[0013] According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the first purge frequency to clean the urea residual liquid of the urea nozzle.

[0014] Preferably, the currently enabled operating mode of the engine is a parking mode;

[0015] According to a control strategy matching the currently enabled operation mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the urea residual liquid of the urea nozzle, including:

[0016] obtaining a second purge frequency of the high pressure gas;

[0017] The high-pressure gas is discharged from the air hole of the designated device at the second purge frequency for a preset time period to clean the urea residual liquid in the urea nozzle.

[0018] Preferably, the currently enabled operating mode of the engine is a mode other than the regeneration mode and the parking mode;

[0019] According to a control strategy matching the currently enabled operation mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the urea residual liquid of the urea nozzle, including:

[0020] obtaining a third purge frequency of the high pressure gas;

[0021] According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the third purge frequency to clean the urea residual liquid of the urea nozzle.

[0022] Preferably, the designated device is a heating pad.

[0023] A second aspect of an embodiment of the present invention discloses a system for preventing urea nozzle from crystallizing, the system comprising:

[0024] A heating unit, used for heating a designated device to dissolve urea crystals of a urea nozzle of the vehicle when the vehicle is started, wherein the designated device is installed at the nozzle of the urea nozzle and is provided with a plurality of air holes;

[0025] an identification unit for identifying a currently enabled operating mode of an engine of the vehicle;

[0026] The purge unit is used to discharge high-pressure gas from the air holes of the designated device to clean the urea residual liquid of the urea nozzle according to a control strategy matching the operating mode currently enabled by the engine, wherein the direction in which the high-pressure gas is discharged from the air holes of the designated device is the same as the direction in which the urea nozzle sprays urea.

[0027] Preferably, the currently enabled operating mode of the engine is a regeneration mode, and the purge unit is specifically used for:

[0028] Obtaining a first purge frequency of the high pressure gas;

[0029] According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the first purge frequency to clean the urea residual liquid of the urea nozzle.

[0030] Preferably, the currently enabled operating mode of the engine is a parking mode, and the purge unit is specifically used for:

[0031] obtaining a second purge frequency of the high pressure gas;

[0032] The high-pressure gas is discharged from the air hole of the designated device at the second purge frequency for a preset time period to clean the urea residual liquid in the urea nozzle.

[0033] Preferably, the currently enabled operating mode of the engine is a mode other than the regeneration mode and the parking mode, and the purge unit is specifically used for:

[0034] obtaining a third purge frequency of the high pressure gas;

[0035] According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the third purge frequency to clean the urea residual liquid of the urea nozzle.

[0036] Preferably, the designated device is a heating pad.

[0037] Based on the above-mentioned embodiment of the present invention, a method and system for preventing urea nozzle crystallization is provided. The method is as follows: when the vehicle is started, a designated device is heated to dissolve urea crystals in the vehicle's urea nozzle, the designated device is installed at the nozzle of the urea nozzle, and the designated device is provided with multiple air holes; the operating mode currently enabled by the vehicle's engine is identified; according to a control strategy matching the operating mode currently enabled by the engine, high-pressure gas is discharged from the air holes of the designated device to clean the urea residual liquid in the urea nozzle. This solution dissolves the urea crystals in the urea nozzle by heating the designated device installed at the nozzle of the urea nozzle, and cleans the urea residual liquid in the urea nozzle by discharging high-pressure gas from the air holes of the designated device, thereby avoiding urea crystallization around the urea nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0039] Figure 1 A structural example diagram of a conventional urea injection system provided in an embodiment of the present invention;

[0040] Figure 2 A flow chart of a method for preventing urea nozzle crystallization provided by an embodiment of the present invention;

[0041] Figure 3 An example diagram of a designated device provided by an embodiment of the present invention;

[0042] Figure 4 An example diagram of control logic of a method for preventing urea nozzle crystallization provided by an embodiment of the present invention;

[0043] Figure 5 A structural block diagram of a system for preventing urea nozzle crystallization provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0046] Before explaining this plan, some of the terms involved in the subsequent content are explained:

[0047] Selective Catalytic Reduction (SCR) technology: SCR is a treatment process for nitrogen oxides (NOx) in diesel vehicle exhaust emissions.

[0048] Urea crystals (usually automotive urea crystals) are various by-products caused by urea evaporation and precipitation due to system problems or poor system reactions when the vehicle's SCR system is working.

[0049] The use of urea is the main measure to reduce nitrogen oxide (NOx) emissions, which can ensure that vehicles meet emission standards. However, in the actual use of urea, the urea nozzle is prone to abnormal crystallization, which will affect the normal injection of urea and cause abnormal emissions, thus affecting the normal use of the vehicle by users.

[0050] Research has found that when the urea nozzle is working normally, the highly atomized urea liquid particles are prone to remain on the catalyst box wall and accumulate over time. As the large injection volume continues to operate, low-temperature operation will also aggravate the accumulation of atomized urea liquid, eventually leading to urea crystallization at the urea nozzle, which in turn affects the normal urea injection. Abnormal urea injection will also affect the normal use of the vehicle.

[0051] In order to solve the problem of "urea accumulation and crystallization caused by sprayed atomized urea falling near the urea nozzle", the present invention proposes a method and system for preventing urea nozzle crystallization, which dissolves urea crystals in the urea nozzle by heating a designated device installed at the nozzle of the urea nozzle, and cleans urea residual liquid in the urea nozzle by discharging high-pressure gas from the air holes of the designated device, thereby avoiding urea crystallization around the urea nozzle.

[0052] It should be noted that the present solution is used to prevent the urea nozzle in the urea injection system of the vehicle from crystallizing. Before explaining the present solution, a conventional urea injection system is first explained.

[0053] See also Figure 1 , shows a structural example diagram of a conventional urea injection system provided in an embodiment of the present invention, the urea injection system at least includes a urea nozzle 101, an SCR assembly 102, a urea pressure pipe 103 and an integrated urea tank assembly 104, and the urea nozzle 101 is installed at the "urea nozzle installation port 105".

[0054] See also Figure 2 , shows a flow chart of a method for preventing urea nozzle crystallization provided by an embodiment of the present invention, the method comprising:

[0055] Step S201: When the vehicle is started, a designated device is heated to dissolve urea crystals in a urea nozzle of the vehicle.

[0056] It should be noted that the designated device is installed at the nozzle of the urea nozzle, and the designated device is provided with a plurality of air holes (for example, 4 air holes are symmetrically provided).

[0057] Specifically, the designated device is installed at the installation position of the urea nozzle and the SCR assembly, and the designated device is combined with the gasket of the urea nozzle, so that the designated device can be installed at the nozzle periphery of the urea nozzle.

[0058] The high-pressure gas pressurized by the vehicle's air compressor is discharged (or blown out) through the air holes of the designated device, and the designated device is heated by the heat source of the vehicle, thereby preventing and eliminating urea crystallization.

[0059] In some specific embodiments, the designated device is a heating pad, such as Figure 3 As can be seen from the example diagram of the designated device shown, the designated device is a heating pad 301, and the heating pad 301 is symmetrically provided with four air holes 302 (the number can be set according to actual conditions, and the four air holes are only used as an example). The heating pad 301 is combined with the gasket of the urea nozzle to be installed at the nozzle periphery of the urea nozzle;

[0060] The high-pressure gas pressurized by the air compressor 303 of the vehicle is blown out through the four air holes 302 of the heating pad 301 , and the heat source 304 of the vehicle heats the heating pad 301 .

[0061] In the specific implementation of step S201 , when the vehicle is started, the designated device (such as a heating pad) is heated by the heat source of the vehicle, and the urea crystals of the urea nozzle are dissolved by the heated designated device.

[0062] It should be noted that, since the designated device is combined with the gasket of the urea nozzle and installed at the periphery of the nozzle, after the designated device is heated, the heated designated device will thermally dissolve the urea crystal blocks focused at the periphery of the urea nozzle, that is, after abnormal urea crystals appear in the urea nozzle, the thermal dissolution of the urea crystal blocks can be completed by heating the designated device.

[0063] Step S202: Identify the operating mode currently enabled by the vehicle's engine.

[0064] In the specific process of implementing step S202 , the currently enabled operating mode of the engine of the vehicle is identified, and the currently enabled operating mode of the engine is a regeneration mode, a parking mode or other modes.

[0065] Step S203: according to a control strategy matching the currently enabled operation mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the urea residual liquid in the urea nozzle.

[0066] It should be noted that the direction in which the high-pressure gas is discharged from the air hole of the designated device is the same as the direction in which the urea nozzle sprays urea, so as to avoid affecting the airflow.

[0067] The high-pressure gas is discharged from the gas hole of the designated device, so that the high-pressure gas purges the nozzle periphery of the urea nozzle.

[0068] In the process of specifically implementing step S203, according to the control strategy matching the currently enabled operating mode of the engine, the vehicle's air compressor is used to discharge high-pressure gas from the air holes of the designated device for cleaning the urea residual liquid in the urea nozzle. The process of "discharging high-pressure gas from the air holes of the designated device" is called high-pressure purging. The air compressor is used to perform high-pressure treatment on air to obtain high-pressure gas.

[0069] The control strategies adopted for discharging high-pressure gas are different depending on the operating mode currently enabled by the engine. The control strategies for discharging high-pressure gas in different operating modes are described in detail below.

[0070] (i) The currently enabled operating mode of the engine is the regeneration mode, and the method of discharging the high-pressure gas from the air hole of the designated device is: obtaining a first purge frequency of the high-pressure gas (for example, 600 Hz);

[0071] According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the first purge frequency to clean the urea residual liquid of the urea nozzle.

[0072] That is to say, if the currently enabled operating mode of the engine is the regeneration mode, the first purge frequency of the high-pressure gas and the interval frequency of the urea nozzle injecting urea are obtained, and the interval frequency of the urea nozzle injecting urea can be used to determine the moment when the urea nozzle has an injection action (the action of injecting urea) and the moment when there is no injection action.

[0073] According to the interval frequency of urea injection from the urea nozzle, determine whether the urea nozzle is injecting; if the urea nozzle is injecting (ie, urea is being injected), the high-pressure gas is not discharged at this time (ie, high-pressure purging is not performed);

[0074] If the urea nozzle does not spray, the high-pressure gas is discharged from the air hole of the designated device at the first purge frequency, and the high-pressure effect of the high-pressure gas is used to complete the cleaning of the urea residual liquid in the urea nozzle.

[0075] In the above manner, high-pressure purging and urea injection of the urea nozzle work at different times, which can avoid disturbing the atomization effect of urea.

[0076] (ii) The currently enabled operating mode of the engine is the parking mode, and the method for discharging the high-pressure gas from the air hole of the designated device is: obtaining a second purge frequency (e.g., 10 Hz) of the high-pressure gas; discharging the high-pressure gas from the air hole of the designated device at the second purge frequency for a preset time (e.g., 2 minutes) to clean the urea residual liquid in the urea nozzle.

[0077] That is, if the currently enabled operating mode of the engine is the parking mode, the high-pressure gas is discharged from the air holes of the designated device at the second purge frequency, and the high-pressure purge is continued for a preset time to clean the urea residual liquid in the urea nozzle.

[0078] (III) When the currently enabled operating mode of the engine is any mode other than the regeneration mode and the parking mode, the method for discharging the high-pressure gas from the air hole of the designated device is as follows: obtaining a third purge frequency (e.g., 60 Hz) of the high-pressure gas; and discharging the high-pressure gas from the air hole of the designated device at the third purge frequency when the urea nozzle has no injection action according to the interval frequency of urea injection of the urea nozzle, so as to clean the urea residual liquid in the urea nozzle.

[0079] It should be noted that the first to third purge frequencies mentioned above can be set according to actual conditions, and no specific limitation is made to these purge frequencies herein.

[0080] In the embodiment of the present invention, urea crystals of the urea nozzle are dissolved by heating a designated device installed at the nozzle of the urea nozzle, and urea residual liquid of the urea nozzle is cleaned by discharging high-pressure gas from the air holes of the designated device, thereby avoiding urea crystals around the urea nozzle.

[0081] To better understand the above embodiments of the present invention Figure 2 For example, the specified device is a heating pad. Figure 4 An example diagram of control logic of a method for preventing urea nozzle crystallization is shown for illustration.

[0082] like Figure 4 It can be seen that when the vehicle is started, the heating pad is heated using the heat source of the vehicle, and then the operating mode currently enabled by the engine is determined.

[0083] (1) When the currently enabled operation mode of the engine is other than the regeneration mode and the parking mode, the third purge frequency of the high-pressure gas is obtained to be 60 Hz, and the interval frequency of the urea nozzle spraying urea is obtained; when the urea nozzle is spraying, the high-pressure purge is not performed (that is, the high-pressure gas is not in action); when the urea nozzle is not spraying, the high-pressure purge is performed (that is, the high-pressure gas is discharged from the air hole of the heating pad at 60 Hz).

[0084] (2) When the currently enabled operating mode of the engine is the regeneration mode, the first purge frequency of the high-pressure gas is obtained to be 600 Hz, and the interval frequency of the urea nozzle spraying urea is obtained; when the urea nozzle is spraying, the high-pressure purge is not performed (that is, the high-pressure gas is not in action); when the urea nozzle is not spraying, the high-pressure purge is performed (that is, the high-pressure gas is discharged from the air hole of the heating pad at 600 Hz).

[0085] (3) When the engine is in parking mode, the second purge frequency for obtaining high-pressure gas is 10 Hz, and high-pressure purge is performed for 2 minutes (preset duration), that is, high-pressure gas is discharged from the air holes of the heating gasket at 10 Hz for 2 minutes.

[0086] In general, this solution is divided into two parts: heat source heating and high-pressure purging. Between urea injection intervals, the air is treated with high pressure by an air compressor, and the high-pressure gas is discharged from the air holes of the designated device according to the purging frequency (any one of the first purging frequency to the third purging frequency). The high-pressure effect of the high-pressure gas is used to clean the urea residual liquid in the urea nozzle. After abnormal urea crystals appear in the urea nozzle, the abnormal urea crystals are thermally dissolved by the heated designated device, and the urea crystals in the urea nozzle can be removed by purging with high-pressure gas.

[0087] In other words, the present invention utilizes a designated device installed around the urea nozzle to complete a fixed-frequency high-pressure purge, thereby reducing the residual and accumulation of urea liquid in the urea nozzle and fundamentally preventing urea crystallization at the urea nozzle. Specifically, the high-pressure purge and urea injection processes can be time-avoided by the interval frequency of urea injection, that is, a high-pressure purge is completed between two urea injections. The entire process completes the urea cleaning of the urea nozzle without affecting the mixing of urea injection and air, thereby preventing urea from accumulating to form a large number of urea crystals and affecting normal urea injection. For the formation of urea crystals in the urea nozzle under special circumstances, the urea crystals can be thermally dissolved by the heated designated device, and the urea crystals can be cleaned in conjunction with the high-pressure purge.

[0088] Corresponding to the method for preventing urea nozzle crystallization provided by the above embodiment of the present invention, see Figure 5 , the embodiment of the present invention also provides a structural block diagram of a system for preventing urea nozzle crystallization, the system comprising: a heating unit 501, an identification unit 502 and a purge unit 503;

[0089] The heating unit 501 is used to heat the designated device to dissolve urea crystals of the urea nozzle of the vehicle when the vehicle is started. The designated device is installed at the nozzle of the urea nozzle and is provided with a plurality of air holes.

[0090] In some embodiments, the designated device is a heating pad.

[0091] The identification unit 502 is used to identify the operating mode currently enabled by the engine of the vehicle.

[0092] The purge unit 503 is used to discharge high-pressure gas from the air holes of the designated device to clean the urea residual liquid of the urea nozzle according to the control strategy matching the currently enabled operation mode of the engine, wherein the direction in which the high-pressure gas is discharged from the air holes of the designated device is the same as the direction in which the urea nozzle sprays urea.

[0093] In some embodiments, the currently enabled operating mode of the engine is the regeneration mode, and the purge unit 503 is specifically used to: obtain a first purge frequency of the high-pressure gas; and discharge the high-pressure gas from the air hole of the designated device at the first purge frequency when the urea nozzle has no injection action according to the interval frequency of the urea nozzle injecting urea, so as to clean the urea residual liquid in the urea nozzle.

[0094] In some other embodiments, the currently enabled operating mode of the engine is the parking mode, and the purge unit 503 is specifically used to: obtain a second purge frequency of the high-pressure gas; discharge the high-pressure gas from the air holes of the designated device at the second purge frequency and continue for a preset time to clean the urea residual liquid in the urea nozzle.

[0095] In some other embodiments, the currently enabled operating mode of the engine is a mode other than the regeneration mode and the parking mode, and the purge unit 503 is specifically used to: obtain a third purge frequency of the high-pressure gas; and discharge the high-pressure gas from the air hole of the designated device at the third purge frequency when the urea nozzle has no injection action according to the interval frequency of the urea nozzle injecting urea, so as to clean the urea residual liquid in the urea nozzle.

[0096] In summary, the embodiments of the present invention provide a method and system for preventing urea nozzle crystallization, which dissolves urea crystals of the urea nozzle by heating a designated device installed at the nozzle of the urea nozzle, and cleans urea residual liquid of the urea nozzle by discharging high-pressure gas from the air holes of the designated device, thereby avoiding urea crystallization around the urea nozzle.

[0097] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0098] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0099] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preventing urea nozzle from crystallizing, characterized in that: The method comprises: When the vehicle is started, the designated device is heated to dissolve urea crystals of the urea nozzle of the vehicle, the designated device is installed at the nozzle of the urea nozzle, and the designated device is provided with a plurality of air holes; identifying a currently enabled operating mode of an engine of the vehicle; According to a control strategy matching the currently enabled operating mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the residual urea of ​​the urea nozzle, wherein the direction in which the high-pressure gas is discharged from the air hole of the designated device is the same as the direction in which the urea nozzle sprays urea.

2. The method according to claim 1, characterized in that The currently enabled operating mode of the engine is a regeneration mode; According to a control strategy matching the currently enabled operation mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the urea residual liquid of the urea nozzle, including: Obtaining a first purge frequency of the high pressure gas; According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the first purge frequency to clean the urea residual liquid of the urea nozzle.

3. The method according to claim 1, characterized in that The currently enabled operating mode of the engine is the parking mode; According to a control strategy matching the currently enabled operation mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the urea residual liquid of the urea nozzle, including: obtaining a second purge frequency of the high pressure gas; The high-pressure gas is discharged from the air hole of the designated device at the second purge frequency for a preset time period to clean the urea residual liquid in the urea nozzle.

4. The method according to claim 1, characterized in that: The currently enabled operating mode of the engine is a mode other than the regeneration mode and the parking mode; According to a control strategy matching the currently enabled operation mode of the engine, high-pressure gas is discharged from the air hole of the designated device to clean the urea residual liquid of the urea nozzle, including: obtaining a third purge frequency of the high pressure gas; According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the third purge frequency to clean the urea residual liquid of the urea nozzle.

5. The method according to any one of claims 1 to 4, characterized in that: The designated device is a heating pad.

6. A system for preventing urea nozzle from crystallizing, characterized in that: The system comprises: A heating unit, used for heating a designated device to dissolve urea crystals of a urea nozzle of the vehicle when the vehicle is started, wherein the designated device is installed at the nozzle of the urea nozzle and is provided with a plurality of air holes; an identification unit for identifying a currently enabled operating mode of an engine of the vehicle; The purge unit is used to discharge high-pressure gas from the air holes of the designated device to clean the urea residual liquid of the urea nozzle according to a control strategy matching the operating mode currently enabled by the engine, wherein the direction in which the high-pressure gas is discharged from the air holes of the designated device is the same as the direction in which the urea nozzle sprays urea.

7. The system according to claim 6, characterized in that The currently enabled operating mode of the engine is the regeneration mode, and the purge unit is specifically used for: Obtaining a first purge frequency of the high pressure gas; According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the first purge frequency to clean the urea residual liquid of the urea nozzle.

8. The system according to claim 6, characterized in that The currently enabled operating mode of the engine is the parking mode, and the purge unit is specifically used for: obtaining a second purge frequency of the high pressure gas; The high-pressure gas is discharged from the air hole of the designated device at the second purge frequency for a preset time period to clean the urea residual liquid in the urea nozzle.

9. The system according to claim 6, characterized in that The currently enabled operating mode of the engine is a mode other than the regeneration mode and the parking mode, and the purge unit is specifically used for: obtaining a third purge frequency of the high pressure gas; According to the interval frequency of urea injection of the urea nozzle, when the urea nozzle has no injection action, high-pressure gas is discharged from the air hole of the designated device at the third purge frequency to clean the urea residual liquid of the urea nozzle.

10. The system according to any one of claims 6 to 9, characterized in that: The designated device is a heating pad.

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