Control method, device and storage medium for preventing urea nozzle crystallization and blockage

Abstract

The present invention provides a control method for preventing urea nozzle crystallization and blockage. This method utilizes different control methods during the vehicle parking phase and the vehicle cold start phase to minimize urea nozzle crystallization. 1) During the vehicle parking phase, negative pressure is established to pump urea from the urea nozzle as completely as possible, preventing urea from remaining in the nozzle and forming crystals. 2) During the vehicle cold start phase, a high-frequency drive signal is applied to the urea nozzle, causing the valve stem within the nozzle to actuate at high frequencies, shaking the crystals loose and dislodging them, preventing further crystallization.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel engine exhaust aftertreatment, and in particular to a control method, a device and a storage medium for preventing urea nozzles from being crystallized and blocked. Background Art

[0002] To meet stringent emission controls, an SCR (Selective Catalytic Reduction) system is typically used to reduce NOx emissions from diesel engine exhaust. The SCR system injects a urea solution into the exhaust. The urea solution decomposes into NH3 at high temperatures. Under the action of a catalyst, it reacts with NOx in the exhaust, thereby eliminating harmful NOx. The urea injection system includes components such as a urea pump, urea lines, and a urea nozzle. When the engine is shut down, the urea pump backflows urea from the urea nozzle and urea lines to prevent residual urea from forming inside the nozzle. However, it is difficult to completely remove urea from the nozzle, which can cause urea to crystallize inside the nozzle, sticking to the valve stem and spray hole, preventing the nozzle from opening properly. Summary of the Invention

[0003] To solve at least one technical problem in the prior art, the present invention provides a control method, device, and storage medium for preventing urea nozzle crystallization from clogging, thereby minimizing urea nozzle crystallization. To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0004] In a first aspect, an embodiment of the present invention provides a control method for preventing urea nozzle crystallization from clogging, including at least a control method for preventing urea nozzle clogging during a vehicle parking phase; the control method for preventing urea nozzle clogging during a vehicle parking phase includes the following steps:

[0005] Step S10, determine whether the vehicle is powered off; if not, continue to determine; if yes, proceed to the next step;

[0006] Step S12, controlling the urea pump to start back-pumping operation, starting the back-pumping operation timer, and controlling the urea nozzle to close;

[0007] Step S14, controlling the urea pump to continue the back-pumping operation, at this time detecting the signal value of the pressure sensor in the urea pump, and when the pressure sensor signal value is negative pressure and is less than the set negative pressure threshold, controlling the urea nozzle to open;

[0008] Step S16: When the back-pumping operation timer reaches the set time, the urea pump and the urea nozzle are controlled to stop operating.

[0009] Furthermore, the negative pressure threshold is set to 0.8 bar to 0.9 bar.

[0010] Furthermore, the set timing time is several minutes.

[0011] Furthermore, the control method for preventing urea nozzle crystallization from clogging also includes a control method for preventing urea nozzle clogging during a vehicle cold start phase; the control method for preventing urea nozzle clogging during a vehicle cold start phase includes the following steps:

[0012] Step S20: After the vehicle is started, first determine whether the vehicle is in a cold start state; if so, proceed to the next step;

[0013] Step S22, determining whether the urea pump is in a pressure-building state, if not, proceeding to the next step;

[0014] Step S24, outputting a driving signal with a set driving frequency that is more than 5 times higher than the normal driving frequency of the urea nozzle to the urea nozzle, driving the urea nozzle to operate at a high frequency;

[0015] In step S26 , after the urea nozzle starts high-frequency operation, the high-frequency operation timer starts timing, and stops the high-frequency operation of the urea nozzle after the timing ends.

[0016] Furthermore, if the urea pump enters a pressure-building state when the urea nozzle is in high-frequency operation, the high-frequency operation of the urea nozzle is immediately stopped.

[0017] In a second aspect, an embodiment of the present invention provides a control device for preventing urea nozzle crystallization and clogging, comprising:

[0018] a memory storing a computer program;

[0019] The processor is configured to run the computer program, and when the computer program is run, the steps of the control method for preventing urea nozzle crystallization from clogging as described above are executed.

[0020] In a third aspect, an embodiment of the present invention provides a storage medium storing a computer program, wherein the computer program is configured to execute the steps of the control method for preventing urea nozzle crystallization from clogging as described above when running.

[0021] The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0022] This application uses different control methods during the vehicle parking phase and the vehicle cold start phase to prevent urea nozzle crystallization as much as possible;

[0023] 1) When the vehicle is parked, create negative pressure to draw back the urea in the urea nozzle as cleanly as possible to prevent urea from remaining in the nozzle and forming crystals.

[0024] 2) During the cold start phase of the vehicle, by giving the urea nozzle a high-frequency drive signal, the valve stem inside the urea nozzle moves at a high frequency, which can shake the crystals loose and prevent them from becoming more serious. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a urea injection system in an embodiment of the present invention.

[0026] Figure 2 The figure is a flow chart of a control method for preventing urea nozzle blockage during a vehicle parking phase according to an embodiment of the present invention.

[0027] Figure 3 The present invention is a flow chart of a control method for preventing urea nozzle blockage during a vehicle cold start phase. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] In the description of the embodiments of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal connections between two components; and they can refer to wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] like Figure 1As shown, the urea injection system includes a urea pump 1, a urea pipeline 2 and a urea nozzle 3; the inlet of the urea pump 1 is connected to the urea tank, and the outlet of the urea pump 1 is connected to the urea nozzle 3 through the urea pipeline 2;

[0033] like Figure 2 As shown, a control method for preventing urea nozzle crystallization from clogging is provided in an embodiment of the present invention, which includes at least a control method for preventing urea nozzle clogging during a vehicle parking phase; the control method for preventing urea nozzle clogging during a vehicle parking phase includes the following steps:

[0034] Step S10, determine whether the vehicle is powered off; if not, continue to determine; if yes, proceed to the next step;

[0035] Step S12, controlling the urea pump to start back-pumping operation, starting the back-pumping operation timer, and controlling the urea nozzle to close;

[0036] Step S14, controlling the urea pump to continue the back-pumping operation, at this time detecting the signal value of the pressure sensor in the urea pump, and when the pressure sensor signal value is negative pressure and is less than the set negative pressure threshold, controlling the urea nozzle to open;

[0037] Step S16: When the back-pumping operation timer reaches the set time, the urea pump and the urea nozzle are controlled to stop operating.

[0038] The above negative pressure threshold can be set to 0.8bar~0.9bar;

[0039] Set the timing time to several minutes; when the urea pump and urea nozzle stop working, they are in the closed state;

[0040] The control method for preventing urea nozzle blockage during the vehicle parking phase proposed in the present application does not immediately perform a back-pumping operation when it is determined that the vehicle is powered off. Instead, the urea nozzle is closed when the back-pumping operation is started to establish a large negative pressure in the urea nozzle and the urea pipeline. Due to the existence of a large negative pressure, when the urea nozzle is opened after a delay, a sudden suction force is generated, which can draw almost all the urea in the urea nozzle and the urea pipeline back to the urea pump. The amount of urea residual in the urea nozzle will be greatly reduced, which is conducive to preventing urea nozzle crystallization and blockage.

[0041] like Figure 3 As shown, a control method for preventing urea nozzle crystallization from clogging is provided in an embodiment of the present invention, and further includes a control method for preventing urea nozzle clogging during a vehicle cold start phase; the control method for preventing urea nozzle clogging during a vehicle cold start phase includes the following steps:

[0042] Step S20: After the vehicle is started, first determine whether the vehicle is in a cold start state; if so, proceed to the next step;

[0043] In this embodiment, determining whether the vehicle is in a cold start state specifically includes: first diagnosing whether there are faults in the engine cooling water temperature sensor and the ambient temperature sensor; if there are no faults, proceeding to the next step of determining whether the difference between the cooling water temperature and the ambient temperature is less than a set temperature difference threshold, determining that the vehicle is in a cold start state;

[0044] Specifically, the temperature difference threshold is 2°C to 5°C;

[0045] Step S22, determining whether the urea pump is in a pressure-building state, if not, proceeding to the next step;

[0046] Normally, when the vehicle is cold started, it takes about 2 minutes for the exhaust temperature to rise to a temperature that allows the urea pump to build pressure. During this time, operations can be performed to prevent the urea nozzle from clogging without affecting the subsequent normal injection of the urea nozzle.

[0047] In this embodiment, if the urea pump pressure value is less than the set pressure threshold, it is considered that the urea pump is not in the pressure building state; the urea pump pressure value can be obtained by the pressure sensor inside the urea pump;

[0048] Step S24, outputting a driving signal with a set driving frequency that is more than 5 times higher than the normal driving frequency of the urea nozzle to the urea nozzle, driving the urea nozzle to operate at a high frequency;

[0049] In this application, when the urea pump is not in a pressure-building state after a cold start of the vehicle, the urea nozzle is operated at a high frequency for a period of time, which can shake off the urea crystals at the valve stem in the urea nozzle, thereby preventing the urea nozzle from being clogged by crystals.

[0050] In step S26 , after the urea nozzle starts high-frequency operation, the high-frequency operation timer starts timing, and stops the high-frequency operation of the urea nozzle after the timing ends.

[0051] In step S26 , if the urea pump enters a pressure-building state when the urea nozzle is in high-frequency operation, the high-frequency operation of the urea nozzle is immediately stopped to prevent the normal pressure-building of the urea pump from being affected.

[0052] An embodiment of the present invention further provides a control device for preventing urea nozzle crystallization and blockage, comprising: a processor and a memory; the processor and the memory communicate with each other, for example, by being connected and communicating with each other via a communication bus; a computer program is stored in the memory; the processor is configured to run the computer program, and when the computer program runs, the steps of the method described above are executed.

[0053] An embodiment of the present invention further proposes a storage medium, in which a computer program is stored, and the computer program is configured to execute the steps of the method described above when running; the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory (Flash Memory), a hard disk (HDD) or a solid-state drive (SSD), etc.; the storage medium may also include a combination of the above-mentioned types of memory.

[0054] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A control method for preventing urea nozzle crystallization from clogging, characterized in that: At least one control method for preventing urea nozzle blockage during a vehicle parking phase is included; the control method for preventing urea nozzle blockage during a vehicle parking phase comprises the following steps: Step S10, determine whether the vehicle is powered off; if not, continue to determine; if yes, proceed to the next step; Step S12, controlling the urea pump to start back-pumping operation, starting the back-pumping operation timer, and controlling the urea nozzle to close; Step S14, controlling the urea pump to continue the back-pumping operation, at this time detecting the signal value of the pressure sensor in the urea pump, and when the pressure sensor signal value is negative pressure and is less than the set negative pressure threshold, controlling the urea nozzle to open; Step S16: When the back-pumping operation timer reaches the set time, the urea pump and the urea nozzle are controlled to stop operating; It also includes the following steps to prevent urea nozzle clogging during the vehicle cold start phase: Step S20: After the vehicle is started, first determine whether the vehicle is in a cold start state; if so, proceed to the next step; Step S22, determining whether the urea pump is in a pressure-building state, if not, proceeding to the next step; Step S24, outputting a driving signal with a set driving frequency that is more than 5 times higher than the normal driving frequency of the urea nozzle to the urea nozzle, driving the urea nozzle to operate at a high frequency; In step S26 , after the urea nozzle starts high-frequency operation, the high-frequency operation timer starts timing, and stops the high-frequency operation of the urea nozzle after the timing ends.

2. The control method for preventing urea nozzle crystallization from clogging according to claim 1, characterized in that: The negative pressure threshold is set to 0.8 bar to 0.9 bar.

3. The control method for preventing urea nozzle crystallization from clogging according to claim 1, characterized in that: When the urea nozzle is in high-frequency operation, the urea pump enters the pressure-building state, and the high-frequency operation of the urea nozzle is stopped immediately.

4. A control device for preventing urea nozzle crystallization and clogging, comprising: a memory storing a computer program; The processor is configured to run the computer program, and when the computer program is run, the steps of the control method for preventing urea nozzle crystallization from clogging are performed as claimed in any one of claims 1 to 3.

5. A storage medium, characterized in that The storage medium stores a computer program, and the computer program is configured to execute the steps of the control method for preventing urea nozzle crystallization from clogging according to any one of claims 1 to 3 when running.

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