Control method and system for preventing crystallization blockage of urea nozzle

Abstract

The invention discloses a control method and system for preventing crystallization blockage of a urea nozzle. The method comprises the steps that S100, the engine state, the environment temperature, the exhaust flow and the exhaust temperature are obtained; and S200, based on the environment temperature, the exhaust flow and the exhaust temperature, exhaust energy is obtained through calculation. And S300, based on the exhaust energy, the urea rate is obtained through calculation. And S400, based on the state of the transmitter and the exhaust temperature, whether the continuous urea spraying stopping time reaches a preset limiting value or not is judged. And S500, if the urea spraying stopping continuous time exceeds the preset limit value, urea is sprayed to the catalytic converter according to a preset method on the basis of the urea rate. Therefore, according to the control method for preventing crystallization blockage of the urea nozzle, crystallization blockage of the urea nozzle can be effectively prevented, faults are reduced, and influences on normal operation of a vehicle and extra maintenance cost are avoided.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of engine aftertreatment systems, and in particular to a control method and system for preventing urea nozzle crystallization from clogging. Background Art

[0002] The diesel engines of cars all inject urea through the catalyst connected to the exhaust pipe. Urea reacts with NOx in the exhaust gas to generate N2, achieving NOx emission compliance. The urea nozzle is installed on the catalyst and directly contacts the high-temperature engine exhaust. After the urea injection is completed, a small amount of urea solution remains in the inner cavity of the nozzle's spray hole. Since the boiling point of water is lower than that of urea, water evaporates faster, and urea solids are easily precipitated to form deposits that clog the nozzle. This type of deposit is called soft crystals. Soft crystals have low hardness, are easily soluble in water, and are easily decomposed by heat. Under high temperature conditions, soft crystals react chemically to form hard crystals biuret, which are called hard crystals. Hard crystals are difficult to dissolve in water, difficult to pyrolyze, and have strong mechanical stability. Once formed, they are difficult to remove and will clog the nozzle.

[0003] When the engine idles for a long time or runs downhill for a long time, and the exhaust temperature is lower than the urea injection start limit, the urea injection will stop for a long time, and the urea nozzle will easily form soft crystals, and hard crystals will form after a certain period of time. A small amount of soft crystals can be hydrolyzed by the urea solution, and a large amount of soft crystals or hard crystals will block the nozzle. When the vehicle needs to inject urea, the urea nozzle is blocked and urea cannot be injected, and the NOx emission of the diesel engine exceeds the standard.

[0004] At present, the main methods to prevent urea nozzle crystallization and blockage are:

[0005] 1. When designing the nozzle, increase the slope of the inner cavity of the spray hole and shorten the length of the inner cavity to minimize the residual urea solution in the inner cavity;

[0006] 2. Increase the coolant flow rate of the urea nozzle, reduce the nozzle temperature, and slow down the evaporation rate of the urea solution.

[0007] These two methods have limited effect on reducing nozzle crystallization, and a large number of blockage failures still occur.

[0008] After the nozzle crystal blockage failure occurs, the current common practice is:

[0009] 1. The user removes the urea nozzle and manually cleans the crystals from the spray hole. This solution delays the normal operation of the user's vehicle and may not completely clean the crystals in the tiny nozzle hole;

[0010] 2. Directly replace the urea nozzle with a new one. This solution will delay the normal operation of the user's vehicle, incur parts costs and increase the user's cost of use, but it cannot eliminate the fault. Summary of the invention

[0011] The embodiments of the present invention provide a control method and system for preventing urea nozzle crystallization from clogging, which can effectively prevent urea nozzle crystallization from clogging, reduce the occurrence of faults, and avoid affecting the normal operation of the vehicle and additional maintenance costs.

[0012] To achieve the above objectives, in a first aspect, the present invention provides a control method for preventing urea nozzle crystallization from clogging, comprising:

[0013] Step S100, acquiring engine status, ambient temperature, exhaust flow rate and exhaust temperature;

[0014] Step S200, calculating exhaust energy based on the ambient temperature, the exhaust flow rate and the exhaust temperature;

[0015] Step S300, calculating a urea rate based on the exhaust energy;

[0016] Step S400, judging whether the continuous time of urea injection stoppage reaches a preset limit value based on the engine state and the exhaust temperature;

[0017] Step S500: If the continuous time of urea injection suspension exceeds a preset limit, urea is injected into the catalyst according to a preset method based on the urea rate.

[0018] In one embodiment of the present invention, step S100 includes:

[0019] Step S101, after the engine is powered on, obtain the engine status;

[0020] Step S102, obtaining the ambient temperature through an ambient temperature sensor;

[0021] Step S103, obtaining the exhaust flow rate through an exhaust flow rate sensor;

[0022] Step S104, obtaining the exhaust temperature through an exhaust temperature sensor.

[0023] In one embodiment of the present invention, based on the ambient temperature, the exhaust flow rate and the exhaust temperature, the exhaust energy is calculated by a first preset formula, and the first preset formula is:

[0024] Q=((T1-T2)*E*3.6 / 3600)

[0025] Among them, Q is the exhaust energy, T1 is the exhaust temperature, T2 is the ambient temperature, and E is the exhaust flow rate.

[0026] In one embodiment of the present invention, based on the exhaust energy, the urea rate is calculated by a second preset formula, and the second preset formula is:

[0027] M=a*Q+b

[0028] Wherein, M is the urea that can be thermally decomposed per unit time of exhaust energy, a and b are both thermal decomposition constants, and Q is the exhaust energy.

[0029] In one embodiment of the present invention, step S400 includes:

[0030] Step S401, judging whether the urea injection is currently stopped based on the engine state and the exhaust temperature;

[0031] Step S402, if the urea spraying is currently stopped, start a timer to record the continuous time of the urea spraying stop;

[0032] Step S403, during the period when urea spraying is stopped, continuously updating the timing value of the timer;

[0033] Step S404, comparing the timing value with a preset limit value to generate a comparison result;

[0034] Step S405: if the comparison result is that the continuous time does not reach the preset limit, return to step S403;

[0035] Step S406: If the comparison result is that the continuous time exceeds the preset limit, then go to step S500.

[0036] In a second aspect, the present invention provides a control system for preventing urea nozzle crystallization and clogging, comprising: an acquisition module, a first calculation module, a second calculation module, a judgment module and an injection module. The acquisition module is used to acquire the engine state, ambient temperature, exhaust flow rate and exhaust temperature. The first calculation module is used to calculate the exhaust energy based on the ambient temperature, the exhaust flow rate and the exhaust temperature. The second calculation module is used to calculate the urea rate based on the exhaust energy. The judgment module is used to judge whether the continuous time of urea spraying suspension reaches a preset limit based on the engine state and the exhaust temperature. And the injection module is used to inject urea into the catalyst according to a preset method based on the urea rate if the continuous time of urea spraying suspension exceeds the preset limit.

[0037] In one embodiment of the present invention, the acquisition module includes: a first acquisition unit, a second acquisition unit, a third acquisition unit and a fourth acquisition unit. The first acquisition unit is used to acquire the engine state after the engine is powered on. The second acquisition unit is used to acquire the ambient temperature through an ambient temperature sensor. The third acquisition unit is used to acquire the exhaust flow through an exhaust flow sensor. And the fourth acquisition unit is used to acquire the exhaust temperature through an exhaust temperature sensor.

[0038] In one embodiment of the present invention, based on the ambient temperature, the exhaust flow rate and the exhaust temperature, the exhaust energy is calculated by a first preset formula, and the first preset formula is:

[0039] Q=((T1-T2)*E*3.6 / 3600)

[0040] Among them, Q is the exhaust energy, T1 is the exhaust temperature, T2 is the ambient temperature, and E is the exhaust flow rate.

[0041] In a third aspect, the present invention provides an electronic device, comprising:

[0042] at least one processor; and

[0043] a memory communicatively coupled to the at least one processor;

[0044] The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method for preventing urea nozzle crystallization blockage as described above.

[0045] In a fourth aspect, the present invention provides a computer-readable storage medium, comprising a computer program and instructions, which, when executed on a computer, enables the computer to execute the control method for preventing urea nozzle crystallization blockage as described above.

[0046] Compared with the prior art, the control method and system for preventing urea nozzle crystallization blockage according to the present invention, by adding a urea nozzle crystal cleaning mode, calculating the urea injection rate in combination with exhaust energy, and setting a reasonable injection interval and duration, can effectively prevent urea nozzle crystallization blockage, reduce the occurrence rate of failures, ensure the normal operation of the vehicle, and reduce maintenance costs and user usage costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a flow chart of a control method for preventing urea nozzle crystallization blockage in the first embodiment of the present invention;

[0048] Figure 2 It is a structural schematic diagram of a control system for preventing urea nozzle crystallization blockage in the second embodiment of the present invention;

[0049] Figure 3 It is a schematic diagram of the structure of an electronic device in Embodiment 3 of the present invention;

[0050] Figure 4 The present invention is a schematic diagram of the working logic flow of a control method for preventing urea nozzle crystallization blockage according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0051] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention, rather than to limit the embodiments of the present invention. It is also necessary to explain that, for ease of description, only parts related to the embodiments of the present invention are shown in the accompanying drawings, rather than all structures.

[0052] Embodiment 1

[0053] Figure 1 : is a flow chart of a control method for preventing urea nozzle crystallization blockage in the first embodiment of the present invention, such as Figure 1 As shown, embodiment 1 provides a control method for preventing urea nozzle crystallization blockage, which is applied to an engine control unit (ECU), and the method includes:

[0054] Step S100, acquiring engine status, ambient temperature, exhaust flow rate and exhaust temperature;

[0055] Specifically, step S100 obtains four key parameters, namely, engine state, ambient temperature, exhaust flow rate and exhaust temperature, to provide necessary data support for subsequent calculation of exhaust energy, determination of urea injection rate and judgment of whether the continuous time of urea injection suspension reaches a preset limit.

[0056] Step S200, calculating exhaust energy based on the ambient temperature, the exhaust flow rate and the exhaust temperature;

[0057] Specifically, through step S200, an accurate exhaust energy value can be obtained, which provides a key basis for the subsequent determination of the urea injection rate, thereby effectively preventing the occurrence of crystallization blockage of the urea nozzle.

[0058] Step S300, calculating a urea rate based on the exhaust energy;

[0059] Specifically, based on the calculated exhaust energy, a preset formula or algorithm is used to calculate the amount of urea that can be thermally decomposed per unit time under the current exhaust energy conditions, that is, the urea rate. This urea rate is an important basis for subsequent judgment on whether urea needs to be injected and how much urea to inject. Through this step, it can be ensured that urea is injected at the right time and in the right amount, thereby effectively preventing crystallization blockage of the urea nozzle.

[0060] Step S400, judging whether the continuous time of urea injection stoppage reaches a preset limit value based on the engine state and the exhaust temperature;

[0061] Specifically, the engine control unit will determine whether the vehicle is in a state of urea spraying suspension based on the current engine state and exhaust temperature, and will further calculate the continuous time of urea spraying suspension. If this continuous time reaches the preset limit, it means that the urea nozzle may form crystal blockage due to long-term non-injection of urea. At this time, corresponding measures need to be taken to prevent or clear this blockage. The implementation of this step is of great significance for timely detection and prevention of crystal blockage of urea nozzles and ensuring the normal operation of vehicles.

[0062] Step S500, if the continuous time of urea injection suspension exceeds a preset limit, based on the urea rate, urea is injected into the catalyst according to a preset method;

[0063] Specifically, the engine control unit will first check whether the continuous time of urea spray stop exceeds the preset limit. This limit is determined based on system design, emission regulations and experimental data, and aims to balance the relationship between urea consumption, emission performance and system protection. Once it is confirmed that the urea spray stop time exceeds the limit, the system will determine the appropriate urea injection rate based on the current engine operating conditions (such as speed, load, exhaust temperature, etc.) and the preset urea injection strategy. This rate needs to ensure that urea can be fully pyrolyzed and react with nitrogen oxides in the exhaust, while avoiding waste and potential problems caused by excessive injection. The system will control the operation of the urea pump according to the preset urea injection method (such as injection timing, injection amount control algorithm, etc.), and inject urea solution into the exhaust pipe upstream of the catalyst at a determined rate. This process requires precise control of the injection timing and injection amount to ensure that urea is fully mixed and reacted with nitrogen oxides in the exhaust. After the urea injection is resumed, the system will continue to monitor parameters such as the conversion efficiency of the catalyst and the exhaust temperature, and adjust the urea injection rate in a timely manner according to the actual situation. This helps to optimize emission performance and ensure stable operation of the system.

[0064] In a specific embodiment, a urea injection system of a diesel vehicle sets a preset limit of 10 minutes for the urea spray stop time. During vehicle operation, the system enters the urea spray stop state because the engine load is low and the exhaust temperature is insufficient to support effective urea thermal decomposition. However, due to some reason (such as traffic congestion causing the vehicle to idle for a long time), the urea spray stop time exceeds the preset limit of 10 minutes.

[0065] At this point, the system will execute step S500:

[0066] The system detects that the urea injection stop time exceeds the limit and decides to resume urea injection.

[0067] Based on the current engine speed (assumed to be idle), load (very low), and exhaust temperature (possibly still low but high enough to support urea thermal decomposition), the system determines a lower urea injection rate.

[0068] The system starts the urea pump and injects urea solution into the exhaust pipe upstream of the catalyst at a determined rate according to the preset injection timing and quantity control algorithm.

[0069] After urea injection is resumed, the system continuously monitors parameters such as the conversion efficiency and exhaust temperature of the catalyst. If it is found that the conversion efficiency is not ideal or the exhaust temperature is too high, which may damage the catalyst, the system will adjust the urea injection rate in time to optimize emission performance and ensure system safety.

[0070] In this embodiment, step S100 includes:

[0071] Step S101, after the engine is powered on, obtain the engine status;

[0072] Specifically, engine status information usually includes key parameters such as engine speed, load, temperature, etc. These parameters are essential for subsequent steps such as calculating exhaust energy, urea rate, and determining urea spray stop time. By obtaining engine status information in real time, the engine control unit can more accurately determine whether there is a risk of crystallization and blockage in the urea nozzle, and take corresponding preventive measures in a timely manner.

[0073] Step S102, obtaining the ambient temperature through an ambient temperature sensor;

[0074] Specifically, ambient temperature is a key parameter because it affects the physical state and injection effect of urea. In a low temperature environment, urea is more likely to crystallize, so the system needs to adjust the urea injection strategy according to the ambient temperature to avoid crystallization clogging the nozzle. When the ambient temperature sensor detects changes in ambient temperature, it transmits this data to the engine control unit in real time. After receiving the ambient temperature data, the engine control unit will conduct a comprehensive analysis in combination with other parameters (such as exhaust temperature, exhaust flow, engine speed and load, etc.) to determine the best urea injection time and injection amount.

[0075] Step S103, obtaining the exhaust flow rate through an exhaust flow rate sensor;

[0076] Specifically, the exhaust flow sensor is installed in the exhaust system of the engine, which can sense and measure the flow of exhaust gas. When the engine is running, the exhaust flow sensor will continuously collect data and transmit this information to the engine control unit. After receiving the exhaust flow data, the engine control unit will conduct a comprehensive analysis in combination with other parameters (such as exhaust temperature, engine speed and load, etc.) to determine the best urea injection time and injection amount. If the exhaust flow is large, it means that the engine is running at high load. At this time, the system needs to increase the injection amount of urea to ensure that enough urea reacts with nitrogen oxides in the exhaust. Conversely, if the exhaust flow is small, the system will reduce the injection amount of urea accordingly to avoid the risk of crystallization caused by excessive injection.

[0077] Step S104, obtaining the exhaust temperature through an exhaust temperature sensor.

[0078] Specifically, the exhaust temperature sensor is installed in the exhaust system of the engine to monitor the exhaust temperature in real time. This data is crucial for the formulation of the urea injection control strategy. When the engine is running, the exhaust temperature sensor continuously collects exhaust temperature data and transmits this data to the engine control unit. After receiving the exhaust temperature data, the engine control unit will analyze and process it to determine the best time and amount of urea injection. For example, if the exhaust temperature is too high, the system may reduce the amount of urea injected to avoid rapid decomposition of urea at high temperatures and crystallization. Based on the exhaust temperature data, the engine control unit can also make real-time adjustments to the urea injection strategy to ensure the efficient operation of the urea injection system and the cleanliness of the nozzle.

[0079] In this embodiment, based on the ambient temperature, the exhaust flow rate and the exhaust temperature, the exhaust energy is calculated by a first preset formula, and the first preset formula is:

[0080] Q=((T1-T2)*E*3.6 / 3600)

[0081] Where Q represents exhaust energy, usually in kilojoules (kJ) or other energy units;

[0082] T1 represents the exhaust temperature, usually in degrees Celsius (℃);

[0083] T2 represents the ambient temperature, also in degrees Celsius (℃);

[0084] E represents the exhaust flow rate, usually in cubic meters per hour (m 3 / h) or other flow units;

[0085] 3.6 and 3600 are unit conversion factors used to convert flow units from cubic meters per hour to cubic meters per second and to convert the result to kilojoules.

[0086] Specifically, the purpose of this step is to convert the three parameters of ambient temperature, exhaust flow rate and exhaust temperature into a specific exhaust energy value through a specific mathematical formula, so as to be used to calculate the urea injection amount or determine the urea injection timing. For example, suppose the current state of the exhaust system of a diesel vehicle is as follows: exhaust temperature T1 = 400 ° C, ambient temperature T2 = 20 ° C, exhaust flow rate E = 1000m 3 / h; Substitute these values ​​into the first preset formula to calculate the exhaust energy:

[0087] Q=((400-20)*1000*3.6 / 3600)kJ=(380*1000*3.6 / 3600)kJ=3800kJ;

[0088] Therefore, in the above example, the exhaust energy Q is calculated to be 3800 kJ. This value can then be used to calculate the urea injection amount, determine the urea injection timing, or make other related control strategy decisions. Through such calculations, the urea injection can be adjusted more accurately according to the current exhaust conditions, thereby optimizing the performance of the urea injection system and reducing the risk of crystallization blockage.

[0089] In this embodiment, based on the exhaust energy, the urea rate is calculated by a second preset formula, and the second preset formula is:

[0090] M=a*Q+b

[0091] Wherein, M represents the amount of urea that can be thermally decomposed per unit time of exhaust energy, and the unit is usually gram (g) or other mass units;

[0092] a and b are pyrolysis constants, which are obtained through experiments or empirical data and are used to describe the linear relationship between exhaust energy and urea amount during urea pyrolysis;

[0093] Q represents exhaust energy, and the unit is usually kilojoule (kJ) or other energy units, which is calculated by the first preset formula.

[0094] Specifically, the purpose of this step is to determine the amount of urea that can be effectively pyrolyzed and converted into ammonia per unit time under the current exhaust energy, so as to provide a basis for the subsequent calculation of the urea injection amount. For example, assuming that the exhaust energy Q = 3800 kJ is calculated by the first preset formula for the current state of the exhaust system of a diesel vehicle, and the pyrolysis constants a = 0.005 g / kJ and b = 1 g are known.

[0095] Substituting these values ​​into the second preset formula calculates the amount of urea that can be thermally decomposed per unit time:

[0096] M = 0.005 * 3800 + 1 = 19 + 1 = 20g

[0097] Therefore, in the above example, the amount of urea M that can be pyrolyzed per unit time of exhaust energy is calculated to be 20g. This value can then be used to calculate the actual urea injection amount to ensure that the injected urea can be fully pyrolyzed and converted into ammonia in the exhaust system, thereby reacting with nitrogen oxides and reducing emissions. Through such calculation and control, the system can optimize the utilization of urea and reduce unnecessary waste and the risk of crystallization blockage.

[0098] In this embodiment, step S400 includes:

[0099] Step S401, judging whether the urea injection is currently stopped based on the engine state and the exhaust temperature;

[0100] Specifically, the engine control unit will first monitor the engine status parameters in real time, such as speed, load, coolant temperature, etc. These parameters reflect the working condition and thermal state of the engine. At the same time, the system will also obtain exhaust temperature data. Exhaust temperature has an important influence on the thermal decomposition of urea and the reaction efficiency with nitrogen oxides. Combining the engine status and exhaust temperature, the system will make a judgment based on the preset logic or algorithm. These logics or algorithms are usually based on a large amount of experimental data and engineering experience, and are intended to determine whether urea injection is suitable under the current conditions. If the system determines that the current conditions are not conducive to urea injection (such as the engine speed is too low, the load is too small, the exhaust temperature is too low, etc.), it will trigger the urea spray stop state and suspend the urea injection.

[0101] In a specific embodiment, for example, a diesel vehicle is running. When the system executes step S401, it will make the following judgments: the engine speed is 800rpm (idling state), and the load is low; the coolant temperature is 60°C, indicating that the engine has not been fully warmed up; the exhaust temperature is 200°C, which is lower than the temperature threshold required for efficient urea pyrolysis (usually above 250°C). Based on the preset logic judgment, the system believes that the current engine speed is low, the load is small, and the exhaust temperature is low, which is not conducive to the pyrolysis of urea and the reaction with nitrogen oxides. Therefore, the system decides to trigger the urea stop spraying state and suspend the urea spraying. This can avoid the crystallization blockage problem caused by spraying urea under low temperature conditions and save urea consumption.

[0102] Step S402, if the urea spraying is currently stopped, start a timer to record the continuous time of the urea spraying stop;

[0103] Specifically, when the engine control unit determines that the urea injection stop state is currently required based on the engine status and exhaust temperature, it will start a timer. This timer will continue to run until the urea injection is reactivated. The timer records the continuous time of urea injection stop, which is very important for evaluating the performance of the urea system, detecting potential faults, and optimizing the urea injection strategy.

[0104] In a specific embodiment, for example, during the operation of a diesel vehicle, due to the low engine speed and low exhaust temperature, the system determines that it is necessary to enter the urea spray stop state. At this time, the system will execute step S402, start the timer to start recording the continuous time of urea spray stop. If the urea spray stop state lasts for 30 minutes, the timer will record this time. During this period, if the engine speed and exhaust temperature return to a level suitable for urea injection, the system will end the urea spray stop state and stop the timer. Then, the system can evaluate the performance of the urea system based on the recorded urea spray stop time, or perform fault diagnosis and emission compliance inspection.

[0105] Step S403, during the period when urea spraying is stopped, continuously updating the timing value of the timer;

[0106] Specifically, when the system enters the urea spray stop state, a timer is started (as described in step S402). During the urea spray stop period, the system continuously updates the timing value of the timer to reflect the real-time duration of the urea spray stop. This is usually achieved through the system's internal clock or timer, which increments the timer value at a certain time interval (such as every second).

[0107] In a specific embodiment, for example, a diesel vehicle enters a urea spray stop state due to low engine speed and low exhaust temperature. At this time, the system will start the timer and start recording the duration of the urea spray stop. As time goes by, as long as the urea spray stop state remains, the system will continue to update the timing value of the timer. For example, if the urea spray stop state has lasted for 2 minutes, the value of the timer will be 120 seconds (assuming that the timer is updated in seconds). If during this period, the engine speed and exhaust temperature return to a level suitable for urea injection, the system will end the urea spray stop state and stop the timer. At this time, what is recorded on the timer is the continuous time of urea spray stop, and this information can be used for subsequent control decisions, fault diagnosis or emission compliance inspections. In general, step S403 ensures that the system can accurately track the duration of urea spray stop, providing important time information for subsequent urea injection control and fault diagnosis.

[0108] Step S404, comparing the timing value with a preset limit value to generate a comparison result;

[0109] Specifically, the system compares the urea injection stop time recorded by the timer with a preset limit. This preset limit is set based on system design and emission regulations, and it represents a threshold for urea injection stop time. If the timer value exceeds this preset limit, it means that the urea injection stop time has been too long, and some measures may need to be taken to resume urea injection to ensure emission compliance and normal operation of the system.

[0110] In a specific embodiment, for example, a urea injection system of a diesel vehicle sets a preset limit of 5 minutes (i.e., 300 seconds) for the urea spray stop time. During the operation of the vehicle, due to some reasons (such as too low engine speed, too low exhaust temperature, etc.), the system enters the urea spray stop state and starts the timer. As time goes by, the timer continues to update the duration of the urea spray stop. If during this process, the value of the timer reaches 301 seconds (i.e., exceeds the preset limit of 5 minutes), the system will execute step S404, compare the value of the timer with the preset limit, and generate a comparison result. This comparison result will indicate that the urea spray stop time has exceeded the preset limit, and the system may take corresponding control measures based on this result, such as trying to resume urea injection, recording fault codes, or reminding the driver to check, etc. Such a design helps to ensure that the urea injection system can resume work at the right time to reduce emission pollution and protect the normal operation of the system.

[0111] Step S405: if the comparison result is that the continuous time does not reach the preset limit, return to step S403;

[0112] Specifically, when the system executes step S404, after comparing the timer value with the preset limit, a comparison result is generated. If the comparison result shows that the continuous time of urea spraying suspension has not reached the preset limit, the system returns to step S403 and continues to update the timer value to monitor the duration of urea spraying suspension.

[0113] In a specific embodiment, for example, a urea injection system of a diesel vehicle sets a preset limit of 10 minutes (i.e., 600 seconds) for the urea stop injection time. During the operation of the vehicle, the system enters the urea stop injection state for some reason and starts the timer. As time goes by, the timer continues to update the duration of the urea stop injection. When the stop injection state lasts for 5 minutes (i.e., 300 seconds), the system executes step S404 to compare the value of the timer with the preset limit. Since the value of the timer (300 seconds) has not reached the preset limit (600 seconds) at this time, the system will return to step S403 and continue to update the timing value of the timer. In this way, the system will continue to monitor the duration of the urea stop injection until it reaches the preset limit or the urea injection condition is restored. If the stop injection time eventually reaches or exceeds the preset limit, the system may take corresponding control measures, such as trying to resume urea injection, recording fault codes, or reminding the driver to check. Such a design helps to ensure that the urea injection system can resume work at the right time to reduce emission pollution and protect the normal operation of the system.

[0114] Step S406, if the comparison result is that the continuous time exceeds the preset limit, then go to step S500;

[0115] Specifically, when the system executes step S404 and compares the timer value with the preset limit, if the comparison result shows that the continuous time of urea injection suspension has exceeded the preset limit, the system will enter step S500 to perform a series of control and diagnosis operations.

[0116] In a specific embodiment, for example, a urea injection system of a diesel vehicle sets a preset limit of 10 minutes (i.e., 600 seconds) for the urea stop injection time. During the operation of the vehicle, due to some reasons (such as too low engine speed, too low exhaust temperature, etc.), the system enters the urea stop injection state and starts the timer. As time goes by, the timer continues to update the duration of the urea stop injection. If during this process, the value of the timer reaches 601 seconds (i.e., exceeds the preset limit of 10 minutes), the system will execute step S404, compare the value of the timer with the preset limit, and generate a comparison result. This comparison result will indicate that the urea stop injection time has exceeded the preset limit, and the system will enter step S500. In step S500, the system may try to resume urea injection, record fault codes, remind the driver to check, or perform other necessary control and diagnostic operations to ensure emission compliance and normal operation of the system. Such a design helps to ensure that the urea injection system can take corresponding control measures in time when the urea stop injection time is too long to reduce emission pollution and protect the normal operation of the system. At the same time, by recording and diagnosing fault codes, valuable information can also be provided for subsequent repairs and maintenance.

[0117] In this embodiment, the step S500 further includes:

[0118] Data is collected in real time through various sensors installed on the vehicle, including but not limited to engine status (speed, load, etc.), ambient temperature, exhaust flow, exhaust temperature, urea solution concentration, urea pump pressure, nozzle flow, etc. In addition to real-time data, historical data needs to be recorded for trend analysis and pattern recognition. These data are stored in the vehicle's ECU (engine control unit).

[0119] Specifically, a variety of sensors are installed on the vehicle to monitor and collect data related to the engine status, environmental conditions, exhaust system and urea injection system in real time. These data include but are not limited to engine speed, load, ambient temperature, exhaust flow, exhaust temperature, urea solution concentration, urea pump pressure and nozzle flow. The purpose of real-time data collection is to provide accurate information so that the system can make timely adjustments and control decisions to ensure the accuracy and effectiveness of urea injection. In addition to real-time data, the system also records historical data. Historical data includes past sensor readings, urea injection events, fault diagnostic codes, etc. The purpose of recording historical data is to perform trend analysis and pattern recognition to help identify potential problems, optimize urea injection strategies and improve the overall performance of the system. All collected data (real-time data and historical data) are stored in the vehicle's engine control unit. The engine control unit is a central processing unit that is responsible for processing and analyzing data from sensors and making control decisions based on these data. The data stored in the engine control unit can be accessed and extracted by diagnostic tools for further analysis and maintenance.

[0120] The collected raw data is cleaned to remove noise and outliers to ensure the accuracy and reliability of the data. Key features are extracted from the preprocessed data, which should be able to reflect the vehicle operating status and the performance of the urea injection system.

[0121] Specifically, the purpose of data cleaning is to remove noise and outliers from the collected raw data to ensure the accuracy and reliability of the data. Noise and outliers may be caused by sensor failure, data transmission errors or environmental factors, which will interfere with the authenticity and consistency of the data. Noise is identified and removed by applying statistical methods and algorithms, such as filtering, smoothing or threshold setting. Anomaly detection techniques are used to identify and process outliers, such as by replacing outliers with missing values, filling missing values ​​with interpolation methods or correcting them according to context. The cleaned data is more accurate and reliable and can better reflect the true status of the vehicle and urea injection system. The purpose of feature extraction is to extract key features from the preprocessed data, which should be able to reflect the vehicle operating status and the performance of the urea injection system. Key features refer to variables or parameters that are closely related to the vehicle operating status and the performance of the urea injection system and are of great significance to subsequent analysis and decision-making. By analyzing the preprocessed data, the features related to the vehicle operating status and the performance of the urea injection system are identified. These key features are selected and extracted using statistical methods, machine learning algorithms or expert knowledge. The extracted key features can be used for subsequent analysis, modeling, and decision-making to help better understand the vehicle operating status and the performance of the urea injection system.

[0122] In a specific embodiment, the engine control unit collects raw data of a diesel vehicle urea injection system, including engine speed, exhaust temperature, urea injection amount, etc. The following is an example of how to perform data cleaning and feature extraction: It is found that the exhaust temperature sensor reads abnormally high values ​​in certain time periods, which may be caused by sensor failure. Use the threshold setting method to identify these abnormal values ​​and replace them with missing values. Then, use the interpolation method to fill these missing values ​​to ensure the continuity of the data. In the cleaned data, the engine speed and exhaust temperature are identified as features that are closely related to the vehicle's operating status. It is also found that there is a certain relationship between the urea injection amount and the engine speed and exhaust temperature, so it is also used as one of the key features. Through statistical analysis and machine learning algorithms, these key features are extracted and used for subsequent analysis and modeling to evaluate the performance of the urea injection system and optimize it.

[0123] Using machine learning or deep learning models, the model is trained based on historical data and real-time data is used to predict nozzle clogging risk or urea injection efficiency.

[0124] Specifically, historical data related to nozzle clogging risk or urea injection efficiency are collected from the vehicle operation system, including engine status (speed, load, etc.), ambient temperature, exhaust flow, exhaust temperature, urea solution concentration, urea pump pressure, nozzle flow, etc. These data are usually collected in real time by various sensors installed on the vehicle and stored in the vehicle's engine control unit. The collected raw data are cleaned to remove noise and outliers to ensure the accuracy and reliability of the data. Data standardization or normalization is performed so that data of different dimensions can be compared and analyzed on the same scale. The data is divided into training set, validation set and test set for subsequent model training, validation and testing. According to the characteristics of the problem and the nature of the data, a suitable machine learning or deep learning model is selected. For the prediction of nozzle clogging risk, a classification model (such as a convolutional neural network in deep learning) can be used to divide the clogging risk into different levels or categories. For the prediction of urea injection efficiency, a regression model (such as a fully connected neural network in deep learning) can be considered to directly predict the specific value of the injection efficiency. The selected model is trained using the training set data, and the parameters of the model are adjusted through the optimization algorithm so that the model can accurately fit the training data. During the training process, the loss function and performance indicators of the model (such as accuracy, recall, precision, F1 value, etc.) can be monitored to evaluate the training effect of the model. The model is verified using the validation set, and the model's hyperparameters (such as learning rate, batch size, number of iterations, etc.) are adjusted based on the validation results to improve the generalization ability of the model. The trained model is deployed to the vehicle's operating system, and the real-time data is used to predict the nozzle clogging risk or urea injection efficiency. The real-time data is collected by sensors and transmitted to the engine control unit, which calls the deployed model for prediction and outputs the prediction results to the vehicle's control system or driver. Take corresponding control measures based on the prediction results. For example, if the nozzle clogging risk is predicted to be high, the nozzle can be cleaned or replaced in advance; if the urea injection efficiency is predicted to be low, the urea injection strategy can be adjusted to improve the injection efficiency. The prediction results are continuously monitored and evaluated, and the model is continuously optimized based on feedback and data in actual applications to improve the accuracy and reliability of the prediction.

[0125] In a specific embodiment, taking nozzle blockage risk prediction as an example:

[0126] Suppose a diesel vehicle manufacturer wants to use a machine learning model to predict the risk of nozzle clogging to improve the operating efficiency and reliability of the vehicle. They first collected historical data, including the occurrence of nozzle clogging events under different operating conditions, engine status, ambient temperature and other related information. Then, a support vector machine (SVM) was used as a classification model and the model was trained using the training set data. During the training process, the model's hyperparameters and optimization algorithms were adjusted to enable the model to accurately distinguish between high and low clogging risks. Finally, the trained model was deployed to the vehicle's operating system and the real-time data was used to predict the risk of nozzle clogging. When a high risk of clogging is predicted, the vehicle control system will automatically trigger a cleaning procedure or remind the driver to perform inspections and maintenance. Through this process, manufacturers can achieve real-time monitoring and prediction of nozzle clogging risks, thereby improving the operating efficiency and reliability of vehicles and reducing maintenance costs.

[0127] According to the model prediction results, the risk level of the current nozzle blockage is evaluated. For example, different risk thresholds can be set to divide the risk level into three levels: low, medium, and high.

[0128] Specifically, different risk thresholds are set according to business needs or expert experience to classify continuous prediction results into different risk levels. For example, the low risk threshold can be set to 0.3 and the medium risk threshold can be set to 0.7. Then the prediction results between 0 and 0.3 are low risk, between 0.3 and 0.7 are medium risk, and above 0.7 are high risk. According to the set risk threshold, the continuous prediction results of the model are converted into discrete risk levels. As shown in the above example, when the prediction result is 0.2, it corresponds to a low risk level; when the prediction result is 0.5, it corresponds to a medium risk level; when the prediction result is 0.8, it corresponds to a high risk level.

[0129] In a specific embodiment, the ECU collects relevant data such as engine status and ambient temperature in real time and inputs them into the deployed model. The model outputs a predicted probability of nozzle clogging risk, assuming it is 0.65. According to the risk threshold set by the manufacturer (low risk threshold 0.3, medium risk threshold 0.7), it can be judged that the nozzle clogging risk level of this vehicle is medium risk. Therefore, the vehicle control system can trigger the corresponding early warning mechanism to remind the driver or maintenance personnel to pay attention to the nozzle status and consider cleaning or maintenance at an appropriate time to reduce the risk of clogging. Through such a process, manufacturers can evaluate the risk level of nozzle clogging in real time based on the model prediction results, and take corresponding control measures to improve the operating efficiency and reliability of the vehicle.

[0130] A series of urea injection strategies are prepared in advance, including different combinations of injection rate, duration, interval, etc. These strategies should be customized according to factors such as vehicle model, engine characteristics, and urea solution quality.

[0131] Specifically, when formulating a urea injection strategy, a variety of factors need to be considered, including vehicle model, engine characteristics (such as power, speed range, emission level, etc.), urea solution quality (such as concentration, purity, temperature, etc.), and environmental conditions (such as ambient temperature, humidity, etc.). According to the above factors, different parameters such as injection rate, duration, and interval are customized. For example, for a high-power engine, a higher injection rate and a longer injection duration may be required to ensure that enough urea enters the exhaust system to effectively reduce nitrogen oxide emissions. Different injection parameters are combined into a series of urea injection strategies. These strategies should cover various operating conditions that the vehicle may encounter to ensure the best urea injection effect under any circumstances.

[0132] In a specific embodiment, it is assumed that a certain automobile manufacturer produces two different types of diesel vehicles: Type A and Type B. These two models have different engine characteristics and emission level requirements. Type A vehicle: Engine characteristics: medium power, wide speed range, and need to meet stricter emission level requirements. Urea injection strategy: formulate a moderate injection rate, a longer injection time, and a moderate injection interval. This can avoid waste and excessive injection while ensuring that the urea reacts fully. Type B vehicle: Engine characteristics: high power, narrow speed range, but relatively low emission level requirements. Urea injection strategy: formulate a higher injection rate, a shorter injection time, and a shorter injection interval. This can ensure that there is still enough urea entering the exhaust system at high power output to meet emission requirements. In addition, for both models, the injection strategy can be further adjusted according to the quality of the urea solution and environmental conditions. For example, in a cold environment, the urea solution may be more likely to crystallize, so the injection strategy needs to be adjusted to avoid nozzle clogging. Through such a customized urea injection strategy, it can be ensured that different models can achieve the best urea injection effect under different operating conditions, thereby meeting emission standards and vehicle performance requirements.

[0133] According to the risk assessment results, the appropriate injection strategy is selected from the strategy library. For example, when the risk of clogging is high, a strategy of increasing the injection frequency or increasing the injection rate can be selected.

[0134] Specifically, first, it is necessary to obtain the current risk assessment result from the nozzle clogging risk prediction model. This result is usually a numerical value indicating the probability of clogging or the risk level. According to the pre-set risk threshold or level, the current risk assessment result is matched with the injection strategy in the strategy library. For example, if the risk assessment result shows a high risk, the injection strategy corresponding to the high risk level is selected. At the matched risk level, there may be a variety of specific injection strategies to choose from. At this point, the most suitable injection strategy can be further determined based on other operating parameters of the vehicle (such as engine load, exhaust temperature, etc.) and the quality and environmental conditions of the urea solution.

[0135] In a specific embodiment, it is assumed that a diesel vehicle is running, and its ECU collects relevant data in real time and inputs it into the nozzle clogging risk prediction model. The model outputs a probability value representing the current clogging risk, which is assumed to be 0.8 (high risk). According to the pre-set risk threshold, 0.8 belongs to the high risk level. Therefore, it is necessary to select the injection strategy corresponding to the high risk level from the strategy library. Under the high risk level, the strategy library may contain a variety of injection strategies, such as increasing the injection frequency, increasing the injection rate, and extending the injection time. At this time, the ECU further considers other operating parameters of the vehicle, such as high engine load and moderate exhaust temperature. In order to quickly reduce the clogging risk, the ECU selects the strategy of "increasing the injection frequency and increasing the injection rate". The ECU sends the selected injection strategy parameters to the urea injection system, and the system adjusts the injection behavior according to the new parameters to increase the injection amount of urea and try to clear the blockage at the nozzle. Through this process, the vehicle can dynamically adjust the urea injection strategy according to the real-time risk assessment results to reduce the risk of nozzle clogging and maintain an efficient urea injection effect. This helps to improve the emission performance and operating reliability of the vehicle.

[0136] Generate corresponding control instructions based on the selected injection strategy. These instructions should include specific parameters such as injection rate, duration, interval, etc. Send the control instructions to the actuators of the urea injection system (such as urea pump, nozzle, etc.) to ensure that they can inject according to the new strategy.

[0137] Specifically, according to the selected injection strategy, the specific parameters such as injection rate, duration, interval, etc. are specified. These parameters should ensure that the urea injection system can achieve the best injection effect under different operating conditions. The determined injection parameters are encoded into control instructions. These instructions usually exist in the form of digital signals and can be recognized and executed by the actuators of the urea injection system. The control instructions are transmitted to the actuators of the urea injection system, such as urea pumps, nozzles, etc., through the communication network inside the vehicle. After receiving the control instructions, the actuators adjust their working states according to the injection parameters in the instructions. For example, the urea pump will adjust its working pressure and flow rate, and the nozzle will adjust the timing and duration of its opening and closing. When the urea injection system implements the new injection strategy, it will monitor its working state in real time and send feedback signals to the ECU. This helps the ECU to monitor and adjust the injection system in real time.

[0138] In a specific embodiment, for example, the ECU of a diesel vehicle has selected the injection strategy of "increasing the injection frequency and increasing the injection rate" according to the risk assessment results. Now, the ECU needs to generate corresponding control instructions and send these instructions to the actuator of the urea injection system. According to the selected injection strategy, the ECU determines that the specific injection rate is 5 ml per second, the injection duration is 0.2 seconds each time, and the injection interval is once every 2 seconds. The ECU encodes these parameters into control instructions, and the instruction format is "injection rate: 5 ml / s; injection duration: 0.2 seconds; injection interval: 2 seconds". The ECU sends the control instructions to the actuator of the urea injection system, such as the urea pump and the nozzle, through the communication network inside the vehicle. After receiving the instruction, the urea pump adjusts its working pressure and flow rate to ensure that 5 ml of urea solution can be injected per second. After receiving the instruction, the nozzle injects at a frequency of once every 2 seconds and a duration of 0.2 seconds each time. Through this process, the urea injection system of the diesel vehicle can accurately execute the new injection strategy according to the control instructions issued by the ECU to increase the injection amount of urea and try to reduce the risk of nozzle clogging. This helps improve the vehicle's emissions performance and operating reliability.

[0139] Embodiment 2

[0140] Figure 2 Schematic diagram of a control system for preventing urea nozzle crystallization from clogging in Embodiment 2 of the present invention. Figure 2As shown, embodiment 2 provides a control system for preventing urea nozzle crystallization blockage, including: an acquisition module 201, a first calculation module 202, a second calculation module 203, a judgment module 204 and an injection module 205. The acquisition module 201 is used to acquire the engine state, ambient temperature, exhaust flow rate and exhaust temperature. The first calculation module 202 is used to calculate the exhaust energy based on the ambient temperature, the exhaust flow rate and the exhaust temperature. The second calculation module 203 is used to calculate the urea rate based on the exhaust energy. The judgment module 204 is used to judge whether the continuous time of urea spraying stop reaches a preset limit based on the engine state and the exhaust temperature. And the injection module 205 is used to inject urea into the catalyst according to a preset method based on the urea rate if the continuous time of urea spraying stop exceeds the preset limit.

[0141] In this embodiment, the acquisition module 201 includes: a first acquisition unit, a second acquisition unit, a third acquisition unit and a fourth acquisition unit. The first acquisition unit is used to acquire the engine state after the engine is powered on. The second acquisition unit is used to acquire the ambient temperature through an ambient temperature sensor. The third acquisition unit is used to acquire the exhaust flow through an exhaust flow sensor. And the fourth acquisition unit is used to acquire the exhaust temperature through an exhaust temperature sensor.

[0142] In this embodiment, based on the ambient temperature, the exhaust flow rate and the exhaust temperature, the exhaust energy is calculated by a first preset formula, and the first preset formula is:

[0143] Q=((T1-T2)*E*3.6 / 3600)

[0144] Where Q represents exhaust energy, usually in kilojoules (kJ) or other energy units;

[0145] T1 represents the exhaust temperature, usually in degrees Celsius (℃);

[0146] T2 represents the ambient temperature, also in degrees Celsius (℃);

[0147] E represents the exhaust flow rate, usually in cubic meters per hour (m 3 / h) or other flow units;

[0148] 3.6 and 3600 are unit conversion factors used to convert flow units from cubic meters per hour to cubic meters per second and to convert the result to kilojoules.

[0149] In this embodiment, based on the exhaust energy, the urea rate is calculated by a second preset formula, and the second preset formula is:

[0150] M=a*Q+b

[0151] Wherein, M represents the amount of urea that can be thermally decomposed per unit time of exhaust energy, and the unit is usually gram (g) or other mass units;

[0152] a and b are pyrolysis constants, which are obtained through experiments or empirical data and are used to describe the linear relationship between exhaust energy and urea amount during urea pyrolysis;

[0153] Q represents exhaust energy, and the unit is usually kilojoule (kJ) or other energy units.

[0154] In this embodiment, the judgment module 204 includes: a judgment unit, a start unit, an update unit, a generation unit, a return unit and an entry unit. The judgment unit is used to judge whether the current state is in the urea spray stop state based on the engine state and the exhaust temperature. The start unit is used to start the timer to record the continuous time of urea spray stop if the current state is in the urea spray stop state. The update unit is used to continuously update the timing value of the timer during the urea spray stop period. The generation unit is used to compare the timing value with the preset limit value to generate a comparison result. The return unit is used to return to step S403 if the comparison result is that the continuous time does not reach the preset limit. The entry unit is used to enter step S500 if the comparison result is that the continuous time exceeds the preset limit.

[0155] Various variations and specific examples of the control method for preventing urea nozzle crystallization blockage provided in Example 1 are also applicable to the control system for preventing urea nozzle crystallization blockage provided in this embodiment. Through the above detailed description of a control method for preventing urea nozzle crystallization blockage, those skilled in the art can clearly know the implementation method of a control system for preventing urea nozzle crystallization blockage in this embodiment, so for the sake of brevity of the specification, it will not be described in detail here.

[0156] Figure 4 FIG. 1 is a schematic diagram of the working logic flow of a control method for preventing urea nozzle crystallization blockage according to a specific embodiment of the present invention. Figure 4 As shown, in a specific embodiment of the present invention, the working logic of the present invention is as follows:

[0157] S1, after the engine is powered on, the engine status and exhaust flow are output in real time. The exhaust temperature sensor arranged on the catalyst measures the exhaust temperature in real time as the input condition of S2 and S4.

[0158] S2, calculate the exhaust energy Q at this time, as follows: Q = ((exhaust temperature-ambient temperature)*exhaust flow*3.6 / 3600).

[0159] S3, calculate the urea M that can be pyrolyzed per unit time at the current exhaust energy Q, as follows: M = a*Q+b. a and b are pyrolysis constants based on this set of nozzle structures. If all urea is pyrolyzed into ammonia, no crystals will be formed, thus avoiding urea crystals inside the catalyst.

[0160] S4: When the engine is running, if the exhaust temperature is lower than the urea injection limit, the urea injection will stop. The continuous urea injection stop time is counted to determine whether the limit is reached.

[0161] S5: If the continuous stop time of urea spraying reaches the limit, it means there is a risk of soft crystals forming, and the urea nozzle crystal cleaning mode will be entered.

[0162] S6, urea is sprayed continuously for 2s at an injection rate per unit time m, and urea spraying is performed intermittently every 2min to flush out and clean the soft crystals formed in the spray hole in time to avoid the formation of a large number of soft crystals or hard crystals that block the urea nozzle.

[0163] Based on the above, the present invention adds a urea nozzle crystal cleaning mode. After the engine has been running for a long time without spraying urea, it enters this mode to force intermittent urea spraying to clean the crystals in the nozzle to avoid blockage failure; and the exhaust energy is calculated using the exhaust temperature and exhaust flow, and the calculation curve of the amount of completely pyrolyzed urea is fitted in combination with the injection pressure and injection cone angle of the nozzle to avoid the formation of urea crystals in the catalyst due to multiple urea injections; and based on a large amount of test data, the urea nozzle crystal cleaning mode is set to spray urea according to the pyrolysis amount, and the urea is sprayed continuously for 2s at a time, and the urea injection is performed intermittently every 2 minutes.

[0164] Embodiment 3

[0165] Figure 3 is a schematic diagram of the structure of an electronic device in Embodiment 3 of the present invention, such as Figure 3 As shown, the third embodiment further provides an electronic device 300 , which may include: a processor 301 and a memory 302 .

[0166] The memory 302 is used to store programs. The memory 302 may include a volatile memory, such as a random access memory (RAM), such as a static random access memory (SRAM), a double data rate synchronous dynamic random access memory (DDR SDRAM), etc. The memory may also include a non-volatile memory, such as a flash memory. The memory 302 is used to store computer programs (such as applications, function modules, etc. for implementing the above method), computer instructions, etc. The above computer programs, computer instructions, etc. may be partitioned and stored in one or more memories 302. And the above computer programs, computer instructions, data, etc. may be called by the processor 301.

[0167] The above-mentioned computer programs, computer instructions, etc. may be stored in partitions in one or more memories 302 . And the above-mentioned computer programs, computer instructions, etc. may be called by the processor 301 .

[0168] The processor 301 is used to execute the computer program stored in the memory 302 to implement each step of the method involved in the above embodiment.

[0169] For details, please refer to the relevant description in the previous method embodiment.

[0170] The processor 301 and the memory 302 may be independent structures or integrated structures. When the processor 301 and the memory 302 are independent structures, the memory 302 and the processor 301 may be coupled and connected via a bus 303 .

[0171] The electronic device of this embodiment can execute the technical solution in the above method, and its specific implementation process and technical principle are the same, which will not be repeated here.

[0172] Embodiment 4

[0173] Embodiment 4 further provides a computer-readable storage medium, including a computer program and instructions. When the computer program or instructions are executed on a computer, the computer executes a control method for preventing urea nozzle crystallization blockage according to any embodiment of the present invention.

[0174] Computer-readable storage media include: USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical disks, and other media that can store program codes.

[0175] This embodiment also provides a computer program product, which includes: a computer program, which is stored in a readable storage medium. At least one processor of an electronic device can read the computer program from the readable storage medium, and at least one processor executes the computer program so that the electronic device executes the solution provided by any of the above embodiments.

[0176] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0177] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A control method for preventing urea nozzle crystallization blockage, characterized in that: include: Step S100, acquiring engine status, ambient temperature, exhaust flow rate and exhaust temperature; Step S200, calculating exhaust energy based on the ambient temperature, the exhaust flow rate and the exhaust temperature; Step S300, calculating a urea rate based on the exhaust energy; Step S400, judging whether the continuous time of urea injection stoppage reaches a preset limit value based on the engine state and the exhaust temperature; Step S500: If the continuous time of urea injection suspension exceeds a preset limit, urea is injected into the catalyst according to a preset method based on the urea rate.

2. The control method for preventing urea nozzle crystallization blockage according to claim 1, characterized in that: The step S100 includes: Step S101, after the engine is powered on, obtain the engine status; Step S102, obtaining the ambient temperature through an ambient temperature sensor; Step S103, obtaining the exhaust flow rate through an exhaust flow rate sensor; Step S104, obtaining the exhaust temperature through an exhaust temperature sensor.

3. The control method for preventing urea nozzle crystallization blockage according to claim 1, characterized in that: Based on the ambient temperature, the exhaust flow rate and the exhaust temperature, the exhaust energy is calculated by a first preset formula, and the first preset formula is: Q=((T1-T2)*E*3.6 / 3600) Among them, Q is the exhaust energy, T1 is the exhaust temperature, T2 is the ambient temperature, and E is the exhaust flow rate.

4. The control method for preventing urea nozzle crystallization blockage according to claim 1, characterized in that: Based on the exhaust energy, the urea rate is calculated by a second preset formula, and the second preset formula is: M=a*Q+b Wherein, M is the urea that can be thermally decomposed per unit time of exhaust energy, a and b are both thermal decomposition constants, and Q is the exhaust energy.

5. The control method for preventing urea nozzle crystallization blockage according to claim 1, characterized in that: The step S400 includes: Step S401, judging whether the urea injection is currently stopped based on the engine state and the exhaust temperature; Step S402, if the urea spraying is currently stopped, start a timer to record the continuous time of the urea spraying stop; Step S403, during the period when urea spraying is stopped, continuously updating the timing value of the timer; Step S404, comparing the timing value with a preset limit value to generate a comparison result; Step S405: if the comparison result is that the continuous time does not reach the preset limit, return to step S403; Step S406: If the comparison result is that the continuous time exceeds the preset limit, then go to step S500.

6. A control system for preventing urea nozzle crystallization blockage, characterized in that: include: An acquisition module, used to acquire engine status, ambient temperature, exhaust flow rate and exhaust temperature; A first calculation module, configured to calculate exhaust energy based on the ambient temperature, the exhaust flow rate and the exhaust temperature; A second calculation module, configured to calculate a urea rate based on the exhaust energy; A judgment module, used for judging whether the continuous time of urea injection stop has reached a preset limit value based on the engine state and the exhaust temperature; as well as The injection module is used for injecting urea into the catalyst according to a preset method based on the urea rate if the continuous time of stopping the injection of urea exceeds a preset limit.

7. The control system for preventing urea nozzle crystallization blockage according to claim 6, characterized in that: The acquisition module comprises: A first acquisition unit, used for acquiring the engine status after the engine is powered on; A second acquisition unit, configured to acquire the ambient temperature through an ambient temperature sensor; A third acquisition unit, configured to acquire the exhaust flow rate through an exhaust flow rate sensor; and The fourth acquisition unit is used to acquire the exhaust temperature through an exhaust temperature sensor.

8. The control system for preventing urea nozzle crystallization blockage according to claim 6, characterized in that: Based on the ambient temperature, the exhaust flow rate and the exhaust temperature, the exhaust energy is calculated by a first preset formula, and the first preset formula is: Q=((T1-T2)*E*3.6 / 3600) Among them, Q is the exhaust energy, T1 is the exhaust temperature, T2 is the ambient temperature, and E is the exhaust flow rate.

9. An electronic device, characterized in that: include: at least one processor; as well as a memory communicatively coupled to the at least one processor; The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method for preventing urea nozzle crystallization blockage according to any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that: The method comprises a computer program and instructions. When the computer program or the instructions are run on a computer, the computer is enabled to execute the control method for preventing urea nozzle crystallization blockage according to any one of claims 1 to 5.

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