Method and device for determining fault type of gas-driven urea system in vehicle and vehicle

Abstract

The invention discloses a method and device for determining the fault type of a gas-driven urea system in a vehicle and the vehicle. The method comprises the steps that in response to the fact that the gas-driven urea system is in a first working state, collecting equipment is controlled to collect first pressure actually borne by a urea tank; in response to the fact that the pressure difference between the first pressure and the target pressure is larger than or equal to a pressure threshold value, the collection equipment is calibrated, and the calibrated collection equipment is obtained; the state of the gas-driven urea system is controlled to be switched from the first working state to a second working state, and in the second working state, the calibrated collecting device is controlled to collect second pressure of the urea nozzle; and determining the fault type of the gas-driven urea system based on the second pressure and the duty ratio of the urea nozzle. The technical problem of low fault determination accuracy of the vehicle urea system is solved.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more specifically, to a method, apparatus, and vehicle for determining the fault type of a gas-driven urea system in a vehicle. Background Technology

[0002] Currently, the main method for determining the fault type of the urea system in a vehicle is to monitor the pressure changes of the urea nozzle using a single sensor, thereby determining the fault type of the urea system.

[0003] However, the above method cannot distinguish between faults in multiple components within the urea system when determining the fault type, and the fault type identification results are easily affected by component aging and sensor misalignment. Therefore, the technical problem of low accuracy in determining faults in vehicle urea systems remains.

[0004] There is currently no effective solution to the aforementioned technical problems. Summary of the Invention

[0005] This application provides a method, apparatus, and vehicle for determining the fault type of a gas-driven urea system in a vehicle, in order to at least solve the technical problem of low accuracy in determining the fault type of a vehicle urea system.

[0006] According to one aspect of the embodiments of this application, a method for determining the fault type of a gas-driven urea system in a vehicle is provided. A pneumatic urea system includes multiple urea nozzles, a urea tank, and a data acquisition device. The method may include: responding to the pneumatic urea system being in a first operating state, controlling the data acquisition device to acquire the actual first pressure experienced by the urea tank, wherein the first operating state indicates the state of urea flowing from the urea tank to the multiple urea nozzles, a target pressure acting on the urea tank, and the urea flowing from the urea tank to the multiple urea nozzles through the target pressure; calibrating the data acquisition device in response to a pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, obtaining a calibrated data acquisition device, wherein the pressure difference between the first pressure acquired by the calibrated data acquisition device and the target pressure is less than the pressure threshold; controlling the state of the pneumatic urea system to switch from the first operating state to a second operating state, and in the second operating state, controlling the calibrated data acquisition device to acquire a second pressure from the urea nozzles, wherein the second operating state is an injection state in which multiple urea nozzles alternately inject urea into the gas emitted by the vehicle, and the second pressure indicates the pressure applied by the urea nozzles when injecting urea; and determining a fault type of the pneumatic urea system based on the second pressure and the duty cycle of the urea nozzles.

[0007] Optionally, the data acquisition device includes a first data acquisition device and a second data acquisition device. The first data acquisition device acquires pressure states using a liquid medium, and the second data acquisition device acquires pressure states using a gas medium. In response to a pressure difference between a first pressure and a target pressure being greater than or equal to a pressure difference threshold, the data acquisition device is calibrated to obtain a calibrated data acquisition device. This includes: in response to a pressure difference between the first pressure and the target pressure being greater than or equal to the pressure difference threshold, in a first operating state, controlling a gas-driven urea system to perform a pressure-holding operation for a first preset duration, and during the pressure-holding operation, acquiring a first average pressure value acquired by the first data acquisition device and a second average pressure value acquired by the second data acquisition device; in the first operating state, controlling one of a plurality of urea nozzles to perform a spraying operation for a second preset duration, and during the spraying operation, acquiring a third average pressure value acquired by the first data acquisition device and a fourth average pressure value acquired by the second data acquisition device; using the first average pressure value, the second average pressure value, the third average pressure value, and the fourth average pressure value, determining a calibration coefficient for the data acquisition device; and using the calibration coefficient, calibrating the data acquisition device to obtain a calibrated data acquisition device.

[0008] Optionally, the first pressure includes liquid path pressure and gas path pressure. Using the average values ​​of the first, second, third, and fourth pressures, the calibration coefficient of the data acquisition device is determined, including: determining the average pressure of the first and third pressures; determining half of the average pressure as the correction amount for the data acquisition device; determining the maximum value between the liquid path pressure and the gas path pressure, and determining the difference between the maximum value and the correction amount; determining the minimum value between the liquid path pressure and the gas path pressure, and determining the sum between the minimum value and the correction amount; and determining the calibration coefficient based on the difference and the sum.

[0009] Optionally, the operating status information includes displacement information and speed information. The displacement information represents the volume of air compressed and output by the air compressor per unit time, and the speed information represents the number of rotations of the air compressor per unit time. In response to the air compressor being in the pumping state and the unloading valve being de-energized, the first desiccant information is determined based on the pressure status information and the operating status information. This includes: in response to the air compressor being in the pumping state and the unloading valve being de-energized, determining the air compressor's pumping volume using an integral model based on the displacement information, speed information, and pressure status information. The pumping volume represents the volume of air transferred to the air receiver by the air compressor in the pumping state. The first desiccant information is determined based on the pumping volume, wherein the pumping volume and the first desiccant information are positively correlated.

[0010] Optionally, the acquisition device is calibrated using a calibration coefficient to obtain a calibrated acquisition device, including: calibrating the acquisition device using a calibration coefficient in response to the calibration coefficient being less than or equal to a calibration coefficient threshold to obtain a calibrated acquisition device.

[0011] Optionally, the method further includes: determining that the acquisition device is in a fault state in response to the calibration coefficient being greater than the calibration coefficient threshold.

[0012] Optionally, the method further includes: setting target desiccant information for the desiccant based on the vehicle's driving state, wherein the target desiccant information is used to indicate whether the desiccant is in an overused state; determining the functional maintenance duration of the desiccant based on the desiccant information, including: in response to the desiccant information being less than or equal to the target desiccant information and the air handling unit being in a safe mode, adding a preset fixed duration to the initial functional maintenance duration to obtain the functional maintenance duration; in response to the desiccant information being less than or equal to the target desiccant information and the air handling unit not being in a safe mode, determining a first duration increase based on the increase in desiccant information, and adding the first duration increase to the initial functional maintenance duration to obtain the functional maintenance duration; in response to the desiccant information being greater than the target desiccant information, acquiring duration information of the desiccant, wherein the duration information is used to indicate the duration of continuous operation of the desiccant when the desiccant information is greater than the target desiccant information; and determining a second duration increase based on the duration information and the desiccant's increment coefficient, adding the second duration increase to the initial functional maintenance duration to obtain the functional maintenance duration.

[0013] Optionally, the fault type of the gas-driven urea system is determined based on the second pressure and the duty cycle of the urea nozzle, including: testing the gas-driven urea system based on the second pressure and the duty cycle to obtain the test results; and in response to the test results indicating that the gas-driven urea system is in a fault state, determining the fault type based on the second pressure.

[0014] Optionally, the second pressure includes a maximum pressure, a minimum pressure, and an intermediate pressure, where the intermediate pressure is the average of the maximum and minimum pressures. Based on the second pressure and the duty cycle, the gas-driven urea system is tested to obtain a test result, including: in response to the duty cycle being within a preset duty cycle range, determining a first difference between the maximum and intermediate pressures within the same injection cycle, and a second difference between the intermediate and minimum pressures within the same injection cycle; determining the average of the first differences within a preset number of injection cycles, and determining the average of the second differences within a preset number of injection cycles; determining a third difference between the average of the first differences and the self-learning value of the gas-driven urea system, and determining a fourth difference between the average of the second differences and the self-learning value, wherein the self-learning value is used to represent the desired pressure fluctuation level in the gas-driven urea system; in response to the third difference being greater than a first threshold, and / or the fourth difference being greater than the first threshold, determining the test result as the gas-driven urea system being in a fault state.

[0015] Optionally, the gas-driven urea system includes an intake valve and a selective catalytic reduction system. The method further includes: in response to a detection result indicating that the gas-driven urea system is in a fault state, and a third difference is greater than a first threshold, and / or a fourth difference is greater than the first threshold, controlling the intake valve to be in an open state; in response to increasing the first pressure in the urea tank using the open intake valve, recalculating the third and fourth differences; and in response to the recalculated third difference being greater than a second threshold, and / or the fourth difference being greater than the second threshold, determining the conversion efficiency of the selective catalytic reduction system.

[0016] Optionally, the fault type includes urea nozzle failure. In response to the detection result that the gas-driven urea system is in a fault state, the fault type is determined based on the second pressure, including: in response to the detection result that the gas-driven urea system is in a fault state and the conversion efficiency is less than the conversion efficiency threshold, the fault type is determined to be urea nozzle failure.

[0017] Optionally, the multiple urea nozzles include a proximal nozzle and a distal nozzle. Urea nozzle malfunctions include both proximal nozzle malfunctions and distal nozzle malfunctions. In response to a detection result indicating that the gas-driven urea system is in a fault state and the conversion efficiency is less than a conversion efficiency threshold, the malfunction type is determined to be a urea nozzle malfunction, including: in response to a detection result indicating that the gas-driven urea system is in a fault state, the conversion efficiency is less than a conversion efficiency threshold, and a third difference is greater than a second threshold, determining the malfunction type to be a distal nozzle malfunction; and in response to a detection result indicating that the gas-driven urea system is in a fault state, the conversion efficiency is less than a conversion efficiency threshold, and a fourth difference is greater than a second threshold, determining the malfunction type to be a proximal nozzle malfunction.

[0018] Optionally, the fault type includes urea filter failure. In response to the detection result indicating that the gas-driven urea system is in a fault state, the fault type is determined based on a second pressure, including: in response to the detection result indicating that the gas-driven urea system is in a fault state, determining the pressure difference between the first pressure and the intermediate pressure; and in response to the pressure difference being greater than a third threshold, determining the fault type as urea filter failure.

[0019] According to another aspect of the embodiments of this application, a fault type determination device for a gas-driven urea system in a vehicle is also provided. The device may include: a first control unit, configured to control a data acquisition device to acquire the actual first pressure experienced by the urea tank in response to the air-driven urea system being in a first operating state, wherein the first operating state indicates the state in which urea in the urea tank flows to multiple urea nozzles, a target pressure is applied to the urea tank, and the urea in the urea tank flows to the multiple urea nozzles through the target pressure; a calibration unit, configured to calibrate the data acquisition device in response to the pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, to obtain a calibrated data acquisition device, wherein the pressure difference between the first pressure acquired by the calibrated data acquisition device and the target pressure is less than the pressure threshold; a second control unit, configured to control the state of the air-driven urea system to switch from the first operating state to a second operating state, and in the second operating state, control the calibrated data acquisition device to acquire the second pressure of the urea nozzles, wherein the second operating state is an injection state in which multiple urea nozzles alternately inject urea into the gas discharged from the vehicle, and the second pressure indicates the pressure applied by the urea nozzles when injecting urea; and a determination unit, configured to determine the fault type of the air-driven urea system based on the second pressure and the duty cycle of the urea nozzles.

[0020] According to another aspect of the embodiments of this application, a vehicle is also provided. The vehicle may include a memory and a processor. The memory stores an executable program. The processor can be used to run the program, wherein, when the program runs, it executes the method for determining the duration of function retention of the desiccant in the vehicle described in the embodiments of this application.

[0021] According to another aspect of the embodiments of this application, an electronic device is also provided, the electronic device including a memory storing an executable program; and a processor for running the program, wherein the program executes the method of any one of the above when it runs.

[0022] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided. The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to execute the method for determining the duration of function retention of the vehicle dryer according to the embodiments of this application.

[0023] According to another aspect of the embodiments of this application, a processor is also provided. The processor is used to run a program, wherein the program, when running, executes the method for determining the duration of function retention of the dryer canister in a vehicle according to the embodiments of this application.

[0024] According to another aspect of the embodiments of this application, a computer program product is also provided. This computer program product includes a computer program that, when executed by a processor, implements the method for determining the duration of function retention of the dryer canister in a vehicle as described in the embodiments of this application.

[0025] In this embodiment, in response to the gas-driven urea system being in a first operating state, the acquisition device is controlled to acquire the actual first pressure borne by the urea tank; in response to the pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, the acquisition device is calibrated to obtain a calibrated acquisition device; the state of the gas-driven urea system is controlled to switch from the first operating state to a second operating state, and in the second operating state, the calibrated acquisition device is controlled to acquire the second pressure of the urea nozzle; based on the second pressure and the duty cycle of the urea nozzle, the fault type of the gas-driven urea system is determined. That is, in this embodiment, by calibrating the acquisition device in the first operating state, potential measurement deviations of the acquisition device are eliminated, ensuring that the second pressure relied upon for fault diagnosis comes from a more accurate calibrated acquisition device. After switching from the first operating state to the second operating state, this embodiment can perform fault diagnosis based on the second pressure and the duty cycle of the urea nozzle, achieving accurate identification and location of faults in the gas-driven urea system, thereby improving the accuracy of fault determination in the vehicle urea system and solving the technical problem of low fault determination accuracy in the vehicle urea system. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0027] Figure 1 This is a flowchart of a method for determining the fault type of a gas-driven urea system in a vehicle according to an embodiment of this application;

[0028] Figure 2 This is a graph illustrating a diagnostic abnormality of a urea nozzle according to an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of a urea nozzle abnormality diagnosis system according to an embodiment of this application;

[0030] Figure 4 This is a flowchart of a urea system pressure build-up according to an embodiment of this application;

[0031] Figure 5 This is a flowchart illustrating the self-learning process of a urea pressure sensor according to an embodiment of this application;

[0032] Figure 6 This is a flowchart of another urea pressure sensor self-learning process according to an embodiment of this application;

[0033] Figure 7 This is a flowchart of a urea injection / pressure replenishment process according to an embodiment of this application;

[0034] Figure 8 This is a flowchart illustrating a passive monitoring function of a urea system according to an embodiment of this application;

[0035] Figure 9 This is a flowchart of a urea nozzle blockage diagnosis function according to an embodiment of this application;

[0036] Figure 10 This is a flowchart of another passive monitoring function for a urea system according to an embodiment of this application;

[0037] Figure 11 This is a flowchart of a nitrogen and oxygen feedback correction function in a selective catalytic reduction system according to an embodiment of this application;

[0038] Figure 12 This is a flowchart of a urea filter clogging monitoring function according to an embodiment of this application;

[0039] Figure 13 This is a flowchart illustrating the reliability assessment of a urea pressure sensor according to an embodiment of this application.

[0040] Figure 14 This is a schematic diagram of a fault type determination device for a gas-driven urea system in a vehicle according to an embodiment of this application. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0042] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] According to an embodiment of this application, an embodiment of a method for determining the fault type of a gas-driven urea system in a vehicle is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0044] Figure 1 This is a flowchart of a method for determining the fault type of a gas-driven urea system in a vehicle according to an embodiment of this application, such as... Figure 1 As shown, the method may include the following steps.

[0045] Step S102: In response to the gas-driven urea system being in the first working state, control the acquisition device to collect the actual first pressure borne by the urea tank.

[0046] In the technical solution provided in step S102 of this application, the aforementioned gas-driven urea system can be a system that uses pneumatic pressure to drive urea injection. The aforementioned first operating state can be used to indicate the state of urea flowing from the urea tank to multiple urea nozzles. The aforementioned acquisition device can be a sensor for real-time monitoring of the pressure within the gas-driven urea system. The aforementioned sensor can include, but is not limited to, a pneumatic pressure sensor and a liquid pressure sensor. Specifically, the liquid path in the liquid pressure sensor refers to the urea liquid delivery channel in the gas-driven urea system; the pneumatic path in the pneumatic pressure sensor refers to the compressed gas delivery channel that propels the urea liquid in the gas-driven urea system. The aforementioned urea tank can be a storage container for storing an aqueous urea solution. A target pressure is applied to the aforementioned urea tank, and the urea in the aforementioned urea tank flows to multiple urea nozzles through the target pressure. The aforementioned first pressure can be used to indicate the pressure actually detected by the aforementioned acquisition device. The aforementioned target pressure can be used to indicate the pressure preset in the gas-driven urea system to promote stable flow of the urea solution. The urea nozzle mentioned above can be any nozzle used in a gas-driven urea system to precisely control the amount of urea injected, including but not limited to near-end nozzles and far-end nozzles. The near-end nozzle is the nozzle closer to the pressure sensor, and the far-end nozzle is the nozzle further away from the pressure sensor.

[0047] Optionally, in response to the gas-driven urea system being in its first operating state, the data acquisition device can be controlled to collect the actual first pressure borne by the urea tank.

[0048] Optionally, after the gas-driven urea system enters the pressure-building stage, the urea nozzle can be closed to maintain stable pressure. When the pressure reaches dynamic equilibrium and there are no significant fluctuations, the output value in the acquisition device can be read synchronously as the first pressure acquisition result. The acquisition device can acquire the pressure in the gas chamber or on the gas source side, as well as the pressure near the nozzle inlet.

[0049] Optionally, the above method can be used to obtain the actual pressure of the gas-driven urea system under the first working state, providing the original physical quantity basis for subsequent steps.

[0050] Step S104: In response to the pressure difference between the first pressure and the target pressure being greater than or equal to the pressure threshold, the acquisition device is calibrated to obtain the calibrated acquisition device.

[0051] In the technical solution provided in step S104 of this application, the pressure difference can be used to represent the deviation between the target pressure and the first pressure obtained by the acquisition device. The pressure difference can be a condition for determining whether calibration is required (e.g., when a new car rolls off the production line, or when sensor calibration is performed periodically during subsequent operation). The pressure threshold can be used to represent the boundary value for determining whether the acquisition device needs to be calibrated.

[0052] Optionally, after collecting the actual first pressure borne by the urea tank, the collection device can be calibrated in response to the pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, thus obtaining a calibrated collection device.

[0053] Optionally, when the gas-driven urea system is in its first operating state, the deviation of the target pressure from the first pressure is calculated based on the first pressure measured by the acquisition device, resulting in the aforementioned pressure difference. When the aforementioned pressure difference is greater than or equal to the aforementioned pressure threshold, a coefficient for calibrating the acquisition device is generated based on the aforementioned pressure difference. The calibration of the acquisition device may include, but is not limited to, the self-correction or calibration of the acquisition device. The aforementioned coefficient can be added to the output signal of the acquisition device to align the measurement result of the acquisition device with the target pressure. The pressure difference between the first pressure acquired by the calibrated acquisition device and the target pressure is less than the pressure threshold.

[0054] Optionally, the above method can achieve autonomous closed-loop calibration of the acquisition equipment, thereby effectively eliminating systematic measurement deviations caused by factors such as sensor drift, environmental temperature changes, and equipment aging, providing highly reliable input data for subsequent measurements, and significantly improving measurement accuracy.

[0055] Step S106: Control the state of the gas-driven urea system to switch from the first working state to the second working state, and in the second working state, control the calibrated acquisition device to acquire the second pressure of the urea nozzle.

[0056] In the technical solution of step S106 of this application, the second working state can be used to indicate that the gas-driven urea system is ready to inject after completing sensor self-calibration, and the gas-driven urea system is in a working state of asynchronously injecting urea. The second pressure can be used to indicate the dynamic pressure change in the urea liquid path caused by asynchronous injection of the nozzle, which is collected in real time by the calibrated acquisition device in the second working state. The urea liquid path can be used to indicate a closed liquid transmission channel from the outlet of the urea tank to the nozzle inlet, used to transport urea solution and withstand pressure fluctuations during the injection process.

[0057] Optionally, after the sensor self-calibration is completed and the gas-driven urea system is confirmed to be fault-free, the gas-driven urea system is controlled to maintain the rated driving pressure, and the near-end nozzle and the far-end nozzle are sequentially triggered to perform periodic spraying actions in non-overlapping time periods, thereby completing the switch from the first working state to the second working state.

[0058] Optionally, the pressure signal in the urea liquid path is collected in real time using the calibrated acquisition device based on a certain sampling frequency, and the maximum value (which can be represented by Pmax), minimum value (which can be represented by Pmin), and median value of the pressure waveform are extracted for each injection cycle.

[0059] Step S108: Based on the second pressure and the duty cycle of the urea nozzle, determine the fault type of the gas-driven urea system.

[0060] In the technical solution of step S108 of this application, the duty cycle can be used to represent the proportion of time the urea nozzle is in the open state within one injection cycle. The fault type can be used to represent identifiable abnormal states in the gas-driven urea system caused by performance degradation of the urea nozzle or blockage of the liquid path, including but not limited to urea filter blockage and urea nozzle blockage.

[0061] Optionally, after acquiring the second pressure through the acquisition device, the fault type of the gas-driven urea system can be determined based on the second pressure and the duty cycle of the urea nozzle.

[0062] Optionally, a 50% duty cycle is set as the diagnostic benchmark. Combined with the maximum (P_max), minimum (P_min), and median (P_mid) values ​​of the second pressure obtained by the calibrated acquisition equipment, when the difference between the maximum and median values ​​of the second pressure is significantly greater than the corresponding difference previously recorded by the system, it is judged as a remote nozzle malfunction. When the difference between the minimum and median values ​​of the second pressure is greater than the corresponding difference previously recorded by the gas-driven urea system, it can be judged as a near-end nozzle malfunction. The fault type of the gas-driven urea system can be determined by the above method.

[0063] In this embodiment, through steps S102 to S108, in response to the gas-driven urea system being in a first working state, the acquisition device is controlled to acquire the actual first pressure borne by the urea tank; in response to the pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, the acquisition device is calibrated to obtain a calibrated acquisition device; the state of the gas-driven urea system is controlled to switch from the first working state to the second working state, and in the second working state, the calibrated acquisition device is controlled to acquire the second pressure of the urea nozzle; based on the second pressure and the duty cycle of the urea nozzle, the fault type of the gas-driven urea system is determined. That is, in this embodiment, the acquisition device is calibrated in the first working state, thereby eliminating potential measurement deviations and ensuring that the pressure data relied upon for fault diagnosis comes from the calibrated, high-precision acquisition device. This embodiment allows for fault diagnosis based on the second pressure and the duty cycle of the urea nozzle after switching from the first working state to the second working state, achieving accurate identification and location of faults in the gas-driven urea system. This improves the accuracy of fault determination in vehicle urea systems and solves the technical problem of low fault determination accuracy in vehicle urea systems.

[0064] The method described in this embodiment will be further described below.

[0065] As an optional embodiment, the data acquisition device includes a first data acquisition device and a second data acquisition device. The first data acquisition device acquires pressure states using a liquid medium, and the second data acquisition device acquires pressure states using a gas medium. In response to a pressure difference between a first pressure and a target pressure being greater than or equal to a pressure threshold, the data acquisition device is calibrated to obtain a calibrated data acquisition device. This includes: in response to a pressure difference between the first pressure and the target pressure being greater than or equal to the pressure threshold, in a first operating state, controlling a gas-driven urea system to perform a pressure-holding operation for a first preset duration, and during the pressure-holding operation, acquiring a first average pressure value acquired by the first data acquisition device and a second average pressure value acquired by the second data acquisition device; in the first operating state, controlling one of a plurality of urea nozzles to perform a spraying operation for a second preset duration, and during the spraying operation, acquiring a third average pressure value acquired by the first data acquisition device and a fourth average pressure value acquired by the second data acquisition device; using the first average pressure value, the second average pressure value, the third average pressure value, and the fourth average pressure value, determining a calibration coefficient for the data acquisition device; and using the calibration coefficient, calibrating the data acquisition device to obtain a calibrated data acquisition device.

[0066] In this embodiment, the first acquisition device can be a liquid pressure sensor used to represent the pressure state in the urea liquid path. The second acquisition device can be a gas pressure sensor used to represent the pressure state in the gas path. The medium can include, but is not limited to, liquid and gaseous media. For example, in this embodiment, the liquid medium can be a urea solution, and the gaseous medium can be compressed air used to propel urea injection. The first preset duration can represent the pressure holding duration set by the gas-driven urea system in the first operating state to stabilize the pressure, such as 20 seconds. The pressure holding operation can represent the operation process of controlling the gas-driven urea system to stop injecting urea and maintain the pressure in the pipeline unchanged in the first operating state. The first average pressure can represent the average of multiple pressure values ​​continuously acquired by the first acquisition device during the pressure holding operation of the first preset duration (e.g., within 20 seconds). The second average pressure can represent the average of multiple pressure values ​​continuously acquired by the second acquisition device during the pressure holding operation of the first preset duration. The second preset duration can represent the duration for which a urea nozzle is controlled to open and inject urea in the first operating state, such as 1 minute. The aforementioned third average pressure value can be used to represent the average of multiple pressure values ​​continuously collected by the first acquisition device during the second preset duration of the injection operation. The aforementioned fourth average pressure value can be used to represent the average of multiple pressure values ​​continuously collected by the second acquisition device during the second preset duration of the injection operation. The aforementioned calibration coefficient can be used to represent the value calculated based on the first average pressure value, the second average pressure value, the third average pressure value, and the fourth average pressure value.

[0067] Optionally, in the first operating state, the injection action of all urea nozzles is stopped, so that the air-driven urea system is in a static pressure maintenance state; within a first preset duration of 20 seconds, the pressure signal output by the first acquisition device is continuously read, and the arithmetic mean of the readings within the aforementioned duration is calculated as the first pressure average; simultaneously, the pressure signal output by the second acquisition device is synchronously read, and the arithmetic mean of the readings within the aforementioned duration is calculated as the second pressure average. It should be noted that the aforementioned first preset duration of 20 seconds is only an example, and there is no specific limitation on the actual length of the first preset duration.

[0068] Optionally, in the first working state, one of the multiple urea nozzles is selected, the corresponding nozzle opening is set to 50%, and the nozzle is started to inject urea. During a second preset time period of 1 minute, the pressure signal output by the first acquisition device is continuously read, and the arithmetic mean of the readings within this time period is calculated as the third pressure average. Simultaneously, the pressure signal output by the second acquisition device is read, and the arithmetic mean of all readings within this time period is calculated as the fourth pressure average. The relationship between the first and third pressure averages, and the relationship between the second and fourth pressure averages, are compared. Based on the comparison results, the output signal of the first or second acquisition device is adjusted so that the pressure change trends recorded by the two acquisition devices are consistent during the injection and pressure holding phases. The value corresponding to the adjusted output signal is the calibration coefficient. Wherein, if the first acquisition device is a hydraulic pressure sensor, the third pressure average is the hydraulic average; if the second acquisition device is a pneumatic pressure sensor, the fourth pressure average is the pneumatic average. It should be noted that the above-mentioned second preset duration of 1 minute and nozzle opening are only examples, and there are no specific restrictions on the actual length of the second preset duration and the nozzle opening.

[0069] Optionally, the above calibration coefficients are applied to the output signal of the first acquisition device, or to the output signal of the second acquisition device, or to the output signals of both acquisition devices simultaneously, to obtain the adjusted acquisition device, which is also the calibrated acquisition device.

[0070] In the embodiments of this application, the above method can achieve self-calibration of the liquid pressure sensor and the gas pressure sensor by utilizing the working state and pressure response characteristics of the gas-driven urea system itself without relying on external calibration equipment or manual intervention, thereby improving the accuracy of the gas-driven urea system in controlling the injection volume during long-term operation.

[0071] As an optional embodiment, the first pressure includes liquid path pressure and gas path pressure. The calibration coefficient of the data acquisition device is determined using the average values ​​of the first, second, third, and fourth pressures. This includes: determining the average pressure of the first and third pressure averages; determining half of the average pressure as the correction amount for the data acquisition device; determining the maximum value between the liquid path pressure and the gas path pressure, and determining the difference between the maximum value and the correction amount; determining the minimum value between the liquid path pressure and the gas path pressure, and determining the sum between the minimum value and the correction amount; and determining the calibration coefficient based on the difference and the sum.

[0072] In this embodiment, the aforementioned liquid pressure can be used to represent the pressure of the urea solution collected by the first collection device. The aforementioned gas pressure can be used to represent the pressure of the driving gas collected by the second collection device. The aforementioned average pressure can be used to represent the average value of the gas pressure and liquid pressure during the pressure holding and injection phases. The aforementioned correction amount can be used to represent a value obtained by taking a portion of the average value of the gas pressure and hydraulic pressure difference based on the changes in gas pressure and hydraulic pressure during the pressure holding and injection processes; for example, taking half of the average value of the gas pressure difference during the pressure holding and injection processes as the correction amount.

[0073] Optionally, the average pressure is obtained by adding the first average pressure and the third average pressure and dividing by two; half of the average pressure is used as a correction value, and this correction value is fixed for subsequent diagnosis; the liquid pressure collected by the first acquisition device and the gas pressure collected by the second acquisition device are compared, and the larger one is taken as the maximum value; the correction value is subtracted from the maximum value to obtain the difference; the liquid pressure collected by the first acquisition device and the gas pressure collected by the second acquisition device are compared, and the smaller one is taken as the minimum value; the correction value is added to the minimum value to obtain the sum; the difference is used as the calibration coefficient of the first acquisition device or the second acquisition device, or the sum is used as the calibration coefficient of the other acquisition device.

[0074] In this embodiment of the application, the above method can automatically align the output signals of the liquid pressure sensor and the gas pressure sensor based on the pressure response characteristics of the gas-driven urea system during the pressure holding and injection stages, so that the two maintain numerical consistency during system operation, thereby improving the accuracy of urea injection quantity control and providing stable and reliable data support for subsequent diagnosis.

[0075] As an optional embodiment, the acquisition device is calibrated using a calibration coefficient to obtain a calibrated acquisition device, including: calibrating the acquisition device using the calibration coefficient in response to the calibration coefficient being less than or equal to a calibration coefficient threshold to obtain a calibrated acquisition device.

[0076] In this embodiment, the aforementioned calibration coefficient threshold can be used to represent the upper limit of the acceptable range of calibration coefficient variation allowed in the gas-driven urea system. When the value of the calibration coefficient does not exceed the aforementioned calibration coefficient threshold, the calibration coefficient is determined to be valid and can continue to be used for subsequent corrections.

[0077] Optionally, when the above calibration coefficient is less than or equal to the calibration coefficient threshold, the calibration coefficient can be applied to the output signals of the liquid pressure sensor and the gas pressure sensor respectively, so that the liquid pressure sensor and the gas pressure sensor present consistent pressure response values ​​under the same operating conditions.

[0078] In this embodiment, the above method enables self-calibration of the liquid pressure sensor and the gas pressure sensor during the operation of the gas-driven urea system. Without relying on external calibration equipment, it ensures that the pressure response values ​​output by the two sensors remain consistent over a long period of time, thereby improving the accuracy of urea injection quantity control and providing a stable and reliable data basis for diagnosing nozzle blockage or filter blockage faults based on pressure difference fluctuations, thus avoiding misdiagnosis or control failure due to sensor drift.

[0079] As an optional embodiment, the method further includes: determining that the acquisition device is in a fault state in response to a calibration coefficient being greater than a calibration coefficient threshold.

[0080] In the embodiments of this application, the above-mentioned fault state can be used to indicate that the measurement result of the pressure sensor has deviated from the reliable range of the system, and the abnormal change of the calibration coefficient indicates that the pressure sensor has drifted, failed or the pipeline is abnormal.

[0081] Optionally, it can be determined whether the calibration coefficient exceeds a preset threshold; if it does, it can be determined that at least one of the liquid pressure sensor or the gas pressure sensor has lost its calibration validity, and then a "pressure sensor unreliable fault" diagnostic message is reported and a urea pressure sensor reliability fault report is triggered at the same time, and the current calibration coefficient is prohibited from being used for subsequent pressure correction or injection control.

[0082] In this embodiment, the above method can realize real-time self-monitoring and fault isolation of the health status of dual pressure sensors during the operation of the gas-driven urea system. When the calibration coefficient exceeds the preset threshold, the abnormal sensor is automatically identified and locked, triggering the "pressure sensor unreliable fault" alarm, preventing injection control and diagnostic decisions based on unreliable data, thereby effectively avoiding miscontrol of urea injection volume, excessive emissions, or false alarms of other component failures caused by sensor drift or system abnormalities.

[0083] As an optional embodiment, determining the fault type of the gas-driven urea system based on the second pressure and the duty cycle of the urea nozzle includes: detecting the gas-driven urea system based on the second pressure and the duty cycle to obtain a detection result; and, in response to the detection result indicating that the gas-driven urea system is in a fault state, determining the fault type based on the second pressure.

[0084] In this embodiment of the application, the above detection results can be used to indicate whether the corresponding liquid pressure response of the gas-driven urea system deviates from the preset normal fluctuation trend under a specified duty cycle, thereby determining whether the system has abnormal conditions such as nozzle blockage, liquid blockage or pressure sensor malfunction.

[0085] Optionally, the urea nozzle is controlled to perform a single injection action at 50% opening, and the pressure data of the liquid circuit pressure sensor (second pressure) is collected simultaneously during the injection. The pressure value is recorded every 0.5 seconds, and the maximum and minimum pressure values ​​within the time period are extracted every 1 second, and the intermediate pressure value (i.e., the average of two adjacent pressure values) is calculated. If, during the injection process, the difference between the maximum and intermediate pressure values, or the difference between the minimum and intermediate pressure values, shows a continuous abnormal increase or an abnormal fluctuation pattern, the detection result is determined to be that the gas-driven urea system is in a fault state.

[0086] Optionally, when the difference between the maximum pressure and the median pressure is significantly greater than the same pressure difference observed in recent normal injection of the gas-driven urea system, it is determined that the distal nozzle is blocked; when the difference between the minimum pressure and the median pressure is significantly greater than the same pressure difference observed in recent normal injection of the gas-driven urea system, it is determined that the proximal nozzle is blocked; when the difference between the median value of the gas pressure and the liquid pressure fluctuation is continuously greater than a preset threshold, it is determined that the urea filter element is blocked.

[0087] In the embodiments of this application, the above method can realize real-time fault identification of the gas-driven urea system under unsteady injection conditions. By analyzing the dynamic fluctuation pattern of the liquid pressure and the relative relationship between the liquid pressure and the gas pressure during the current injection cycle, it is possible to effectively distinguish three types of faults: far-end nozzle blockage, near-end nozzle blockage, and filter blockage, thereby improving the response speed and accuracy of diagnosis.

[0088] As an optional embodiment, the second pressure includes a maximum pressure, a minimum pressure, and an intermediate pressure, where the intermediate pressure is the average of the maximum and minimum pressures. Based on the second pressure and the duty cycle, the gas-driven urea system is tested to obtain a test result, including: in response to the duty cycle being within a preset duty cycle range, determining a first difference between the maximum and intermediate pressures within the same injection cycle, and a second difference between the intermediate and minimum pressures within the same injection cycle; determining the average of the first differences within a preset number of injection cycles, and determining the average of the second differences within a preset number of injection cycles; determining a third difference between the average of the first differences and a self-learning value of the gas-driven urea system, and determining a fourth difference between the average of the second differences and the self-learning value, wherein the self-learning value is used to represent the desired pressure fluctuation level in the gas-driven urea system; in response to the third difference being greater than a first threshold, and / or the fourth difference being greater than the first threshold, determining that the test result indicates the gas-driven urea system is in a fault state.

[0089] In this embodiment, the aforementioned preset duty cycle range can be used to indicate that the urea nozzle is within a stable injection control range that can trigger pressure fluctuations, such as 25% to 75%. The aforementioned first difference can be used to indicate the degree to which the maximum pressure (represented by Pmax) during the pressure rise phase of a single injection cycle deviates from the dynamic average of the liquid path pressure. The aforementioned second difference can be used to indicate the degree to which the minimum pressure (represented by Pmin) during the pressure fall phase of a single injection cycle deviates from the dynamic average of the liquid path pressure. The aforementioned preset quantity can be a certain number of consecutive injection cycles, such as 10 cycles. The aforementioned average of the first difference can be used to indicate the average shift trend of the liquid path pressure peak value in recent injection cycles, for example, the average of 10 Pmax values. The aforementioned average of the second difference can be used to indicate the average shift trend of the liquid path pressure trough value in recent injection cycles, for example, the average of 10 Pmin values. The aforementioned self-learning value can be used to indicate the desired pressure fluctuation level in the gas-driven urea system, and can be represented by EURP_CHECK. The aforementioned third difference can be used to represent the deviation of the average value of the first difference in the current injection cycle from the average value of the same type in its preceding injection cycles. The aforementioned first threshold can be used to represent the maximum allowable deviation of the dynamic fluctuation of the liquid pressure rise or fall phase in the gas-driven urea system under normal operating conditions from the recent theoretical fluctuation difference.

[0090] Optionally, in response to the duty cycle being within a preset duty cycle range, during the cycle in which the urea nozzle performs the injection action at an opening of 25% to 75%, pressure data is continuously collected by the liquid circuit pressure sensor, and one pressure data point is recorded every 0.5 seconds; for all pressure data within each 1-second window, the maximum pressure value, minimum pressure value, and intermediate pressure value (which can be represented by Pmid) within the above 1-second window are calculated, where Pmid = (Pmax + Pmin) / 2; the first difference (which can be represented by ΔP_up) ΔP_up = Pmax - Pmid and the second difference (which can be represented by ΔP_down) ΔP_down = Pmid - Pmin are calculated as the pressure fluctuation of the above injection cycle.

[0091] Optionally, within 10 consecutive injection cycles, the first difference ΔP_up and the second difference ΔP_down for each cycle are obtained respectively. The arithmetic mean of the 10 ΔP_up values ​​is calculated to obtain the average value of the first difference (which can be represented by AVG_ΔP_up); the arithmetic mean of the 10 ΔP_down values ​​is calculated to obtain the average value of the second difference (which can be represented by AVG_ΔP_down).

[0092] Optionally, the difference between the current first difference (which can be represented by ΔP_up_current) and the average of the first differences is calculated as the third difference (which can be represented by Δ3), where Δ3 = ΔP_up_current - AVG_ΔP_up; the difference between the current second difference and the average of the second differences is calculated as the fourth difference (which can be represented by Δ4), where Δ4 = ΔP_down_current - AVG_ΔP_down.

[0093] Optionally, when the third difference is greater than the first threshold, it is determined that the peak deviation of the fluid pressure rise phase in the current injection cycle has increased significantly and the fluid supply resistance has increased abnormally, which can be identified as a remote nozzle blockage fault; when the fourth difference is greater than the first threshold, it is determined that the recovery of the trough value in the fluid pressure fall phase in the current injection cycle has weakened abnormally, which can be identified as a near-end nozzle blockage fault; when the third difference and the fourth difference are both greater than the first threshold, it can be further verified whether there are multiple abnormalities, and the diagnostic results are still output separately according to the above two types of faults, and are not merged into a single fault type; when only the third difference or only the fourth difference exceeds the limit, and continues to fail to recover to within the threshold for more than 3 consecutive injection cycles, fault diagnosis confirmation is triggered and the corresponding fault code is sent.

[0094] In the embodiments of this application, the above method can accurately distinguish between faults such as remote nozzle blockage and proximal nozzle blockage based solely on real-time collected dynamic fluctuations and statistical trends of hydraulic pressure, significantly improving the response speed, accuracy and engineering robustness of diagnosis.

[0095] As an optional embodiment, the gas-driven urea system includes an intake valve and a selective catalytic reduction system. The method further includes: in response to a detection result indicating that the gas-driven urea system is in a fault state and a third difference is greater than a first threshold, and / or a fourth difference is greater than the first threshold, controlling the intake valve to be in an open state; in response to increasing a first pressure in the urea tank using the open intake valve, recalculating the third and fourth differences; and in response to the recalculated third difference being greater than a second threshold, and / or the fourth difference being greater than the second threshold, determining the conversion efficiency of the selective catalytic reduction system.

[0096] In this embodiment, the intake valve can be an electromagnetic control valve located at the top of the urea tank for injecting compressed air into the gas phase space within the tank. The selective catalytic reduction system can be an exhaust aftertreatment system installed downstream of the engine exhaust pipe, containing a selective catalytic reduction catalyst carrier. The second threshold can be used to represent the critical offset corresponding to when Δ3 or Δ4 still cannot return to the normal range under conditions of increased pressure after the intake valve is opened. The conversion efficiency can be used to represent the ability of the selective catalytic reduction system to reduce nitrogen oxides in the exhaust gas under current operating conditions.

[0097] Optionally, when the third difference is greater than the first threshold, or the fourth difference is greater than the first threshold, it is determined that there is a risk of blockage in the current nozzle; trigger the air intake valve opening command, control the air intake valve to be energized and continuously opened for 5 to 10 seconds at a preset duty cycle (e.g., 50%), inject compressed air into the urea tank to increase the pressure of the urea tank, enhance the driving force of liquid flow, and thus solve the blockage problem.

[0098] It should be noted that the above-mentioned intake valve preset duty cycle, energization opening time, and nozzle malfunction details are for illustrative purposes only, and no specific limitations are imposed on the above-mentioned intake valve preset duty cycle, energization opening time, and nozzle malfunction.

[0099] Optionally, after the intake valve is opened and maintained for a certain period of time, the intake valve is closed, and the gas-driven urea system returns to the original injection control mode. In the subsequent continuous injection cycle, the liquid circuit pressure data continues to be collected, and Pmax, Pmin, and Pmid are calculated every 1 second. The new first difference and second difference are recalculated. Based on the data of the above continuous cycle, the new average value of the first difference (which can be represented by AVG_ΔP_up_new) and the average value of the second difference (which can be represented by AVG_ΔP_down_new) are recalculated. Then, the new third difference (which can be represented by Δ3_new) is calculated, where Δ3_new = ΔP_up_new_current - AVG_ΔP_up_new and the fourth difference can be represented by (Δ4_new), where Δ4_new = ΔP_down_new_current - AVG_ΔP_down_new.

[0100] Optionally, when Δ3_new is greater than the second threshold, or Δ4_new is greater than the second threshold, it can be determined that the intake valve boost cleaning has failed to restore the normal pressure fluctuation of the nozzle, indicating that the nozzle blockage can no longer be cleared by physical flushing. It can be inferred that long-term inefficient injection has led to insufficient ammonia coverage on the surface of the Selective Catalytic Reduction Catalyst (SCR), resulting in a decrease in catalyst activity. At this time, the real-time data of the nitrogen oxide sensors at the SCR inlet and outlet under the current operating conditions can be called, and the conversion efficiency can be calculated based on the above real-time data.

[0101] In the embodiments of this application, the above method can actively pressurize and clean the urea pipeline through the intake valve, and accurately distinguish between reversible nozzle blockage and irreversible SCR catalytic failure based on the dynamic deviation of the pressure fluctuation trend of the liquid circuit before and after cleaning.

[0102] As an optional embodiment, the fault type includes urea nozzle failure. In response to the detection result that the gas-driven urea system is in a fault state, the fault type is determined based on a second pressure, including: in response to the detection result that the gas-driven urea system is in a fault state and the conversion efficiency is less than the conversion efficiency threshold, the fault type is determined to be urea nozzle failure.

[0103] In this embodiment, the aforementioned urea nozzle failure can be used to indicate that the actual injection flow rate of the urea injector nozzle is lower than the theoretical requirement due to carbon deposits, particulate matter deposition, or mechanical wear. The aforementioned conversion efficiency can be used to represent the selective catalytic reduction catalyst's ability to reduce nitrogen oxides in the exhaust gas under current engine operating conditions. The aforementioned conversion efficiency threshold can be used to represent the minimum acceptable conversion efficiency threshold at which the SCR system can still maintain basic emission compliance under nozzle failure conditions.

[0104] Optionally, when the gas-driven urea system determines that it is in a fault state (i.e., Δ3 > first threshold or Δ4 > first threshold), and the intake valve has performed a pressurization cleaning operation and recalculated and confirmed that Δ3_new > second threshold or Δ4_new > second threshold, it indicates that the nozzle blockage cannot be restored by physical flushing. At this time, if the conversion efficiency of the SCR system under the current operating conditions is less than the preset conversion efficiency threshold (e.g., 75%), it can be determined that the decrease in conversion efficiency is caused by insufficient urea injection leading to a shortage of ammonia supply, rather than the aging or poisoning of the SCR catalyst itself. The fault type is then determined to be a urea nozzle fault, and a "urea nozzle flow abnormality" fault code is output. At the same time, the subsequent self-cleaning cycle is disabled, and the user is advised to replace the injector.

[0105] In the embodiments of this application, the above method can accurately distinguish between urea nozzle failure and SCR catalyst failure; by using existing sensors and judging by static thresholds, the root cause of "insufficient ammonia supply from the nozzle" can be identified after the failure occurs, which significantly improves diagnostic accuracy, reduces the false judgment rate and unnecessary catalyst replacement costs.

[0106] As an optional embodiment, the plurality of urea nozzles include a proximal nozzle and a distal nozzle. Urea nozzle malfunctions include both proximal nozzle malfunctions and distal nozzle malfunctions. In response to a detection result indicating that the gas-driven urea system is in a faulty state and the conversion efficiency is less than a conversion efficiency threshold, determining the malfunction type as a urea nozzle malfunction includes: in response to a detection result indicating that the gas-driven urea system is in a faulty state, the conversion efficiency is less than a conversion efficiency threshold, and a third difference is greater than a second threshold, determining the malfunction type as a distal nozzle malfunction; and in response to a detection result indicating that the gas-driven urea system is in a faulty state, the conversion efficiency is less than a conversion efficiency threshold, and a fourth difference is greater than a second threshold, determining the malfunction type as a proximal nozzle malfunction.

[0107] In this embodiment, the aforementioned proximal nozzle failure can be used to indicate that the actual jet flow rate of the proximal nozzle is lower than the theoretical requirement due to localized carbon buildup, particulate matter deposition, or nozzle orifice shrinkage. The aforementioned distal nozzle failure can be used to indicate that the distal nozzle is unable to effectively establish high-pressure pulse jet due to nozzle orifice blockage, flow channel scaling, or valve core jamming.

[0108] Optionally, when the gas-driven urea system is determined to be in a fault state (i.e., Δ> first threshold or Δ4> first threshold), and the intake valve has performed a pressurization cleaning operation, and Δ3_new> second threshold and Δ4_new≤ second threshold are recalculated and confirmed, and the conversion efficiency of the SCR under the current operating condition is less than the preset threshold, it is determined that only the maximum value in the pressure waveform is consistently low while the minimum value is normal, which indicates that the blockage is concentrated in the high-pressure build-up section of the remote nozzle; combined with the design of the remote nozzle undertaking the main injection task, it is determined to be a remote nozzle fault, and the fault code "remote nozzle blockage" is output.

[0109] Optionally, when the gas-driven urea system is determined to be in a fault state (i.e., Δ3>first threshold or Δ4>first threshold), and the intake valve has performed a pressurization and cleaning operation, and Δ4_new>second threshold and Δ3_new≤second threshold are recalculated and confirmed, and the conversion efficiency of the SCR under the current operating condition is less than the preset threshold, if only the minimum value in the pressure waveform continues to rise while the maximum value is normal, it can be concluded that the blockage is concentrated in the backflow or pressure relief section of the near-end nozzle, causing the near-end nozzle to be unable to effectively relieve pressure in the injection gap, thereby affecting the control and flow accuracy of asynchronous injection; it is determined to be a near-end nozzle fault, and the fault code "near-end nozzle backflow blockage" is output.

[0110] For example, self-learning can be performed in a single-pressure mode (i.e., in a pneumatic urea system equipped with only one pressure sensor, pressure fluctuation data during urea injection over a period of time is collected during the initial operation of the vehicle, such as the maximum value, minimum value, and average value), and these values ​​are automatically recorded as self-learning values). When the difference between the maximum urea pressure and the median value and the difference between the self-learning value are greater than a threshold, it can be determined that the distal nozzle is blocked. When the difference between the minimum urea pressure and the median value and the difference between the self-learning value are greater than a threshold, it can be determined that the proximal nozzle is blocked.

[0111] As an optional embodiment, the fault type includes urea filter cartridge failure. In response to the detection result indicating that the gas-driven urea system is in a fault state, the fault type is determined based on a second pressure, including: in response to the detection result indicating that the gas-driven urea system is in a fault state, determining the pressure difference between a first pressure and an intermediate pressure; and in response to the pressure difference being greater than a third threshold, determining the fault type as urea filter cartridge failure.

[0112] In the embodiments of this application, the above-mentioned urea filter failure can be used to indicate that the urea filter has abnormally increased flow resistance due to particulate matter deposition, impurity blockage, or long-term use, resulting in a decrease in energy transfer efficiency between the gas supply system and the liquid load.

[0113] Optionally, when the gas-driven urea system is determined to be in a fault state (i.e., Δ3>first threshold or Δ4>first threshold), and the intake valve has performed a pressurization cleaning operation and recalculated and confirmed that Δ3_new≤second threshold and Δ4_new≤second threshold, it indicates that there is no blockage in either the distal or proximal nozzles. At this time, the difference between the gas pressure (which can be represented by P_gas) and the median value of the liquid pressure fluctuation within the current injection cycle (which can be represented by ΔP_filter) can be calculated. If ΔP_filter>the preset third threshold, and this state continues for more than 3 consecutive diagnostic cycles, it can be determined that the gas supply pressure is normal, but the pressure response at the liquid load end is delayed due to the increased resistance of the filter element, resulting in a stable pressure difference. Thus, the fault type is determined to be a urea filter element fault, and the "urea filter element blockage" fault code is output.

[0114] In this embodiment, the above method can control the acquisition device to collect the actual first pressure borne by the urea tank in response to the gas-driven urea system being in a first working state; calibrate the acquisition device to obtain a calibrated acquisition device in response to the pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold; control the state of the gas-driven urea system to switch from the first working state to a second working state, and in the second working state, control the calibrated acquisition device to collect the second pressure of the urea nozzle; and determine the fault type of the gas-driven urea system based on the second pressure and the duty cycle of the urea nozzle. In other words, in this embodiment, by calibrating the acquisition device in the first working state, potential measurement deviations of the acquisition device are eliminated, ensuring that the second pressure relied upon for fault diagnosis comes from a more accurate calibrated acquisition device. After switching from the first working state to the second working state, this embodiment can perform fault diagnosis based on the second pressure and the duty cycle of the urea nozzle. This achieves accurate identification and location of faults in the gas-driven urea system, thereby improving the accuracy of fault determination in vehicle urea systems and solving the technical problem of low fault determination accuracy in vehicle urea systems.

[0115] The technical solutions of the embodiments of this application will be illustrated below with reference to preferred embodiments.

[0116] Currently, in vehicles meeting China VI and lower emission standards, the precise control and health monitoring of urea injection systems mainly rely on using a single nozzle. The amount of urea injected is controlled by adjusting the nozzle opening and injection frequency. Only one pressure sensor is used to monitor pressure changes within the urea system, thereby inferring the health status of the urea injection system.

[0117] In this embodiment, asynchronous injection using a two-stage nozzle ensures the urea injection volume is as accurate as possible. Since hydraulic pressure cannot replace pneumatic pressure, dual pressure sensors are used: one on the pneumatic side and the other on the hydraulic side near the nozzle. The system's working accuracy is improved by comparing the pressure sensor measurements. Due to the introduction of dual pressure sensors, self-correction of the sensors is required to ensure the reliability of the calibration results.

[0118] In this embodiment, filter blockage is diagnosed by the difference between two sensors, and two nozzles are diagnosed by the change in liquid pressure. Preferably, 50% opening is used as the diagnostic duty cycle.

[0119] In this embodiment, the pressure sensor self-correction includes: performing the first self-correction after the new vehicle rolls off the production line and the urea injection system is ready for operation; firstly, pressure change data during the pressure build-up process can be collected, and pressure can be maintained for 20 seconds after the pressure build-up is completed, recording the average readings of the two sensors; the near-end urea nozzle can be opened to spray at 50% opening, and the maximum pressure value on the hydraulic circuit side can be recorded second by second, maintaining 1 group, and taking the average hydraulic pressure and average air pressure of the last 20 seconds; finally, half of the average air pressure difference during the pressure holding and injection processes can be taken as the correction amount, the larger of the hydraulic circuit pressure and air circuit pressure can be subtracted from the correction amount, and the smaller of the two pressures can be increased by the correction amount, so that the pressure values ​​are equal and centered, and this correction amount can be fixed for subsequent diagnosis; subsequently, the sensor can be calibrated periodically according to the running time (changing coefficients), and when the correction amount is greater than the threshold, a pressure sensor unreliable fault can be reported.

[0120] Optionally, self-learning is performed in a single-pressure mode; when the difference between the maximum urea pressure and the median value and the difference between the self-learned value is greater than a threshold, the distal nozzle is determined to be blocked; when the difference between the minimum urea pressure and the median value and the difference between the self-learned value is greater than a threshold, the proximal nozzle is determined to be blocked.

[0121] Optionally, a maximum and minimum value (A1 / A2, B1 / B2) are calculated every 0.5 seconds, a maximum and minimum value are obtained within 1 second, and the average of the remaining two pressures is calculated as the median value.

[0122] Optionally, the filter element is considered clogged when the difference between the midpoint of the air pressure and urea pressure fluctuations is greater than a threshold.

[0123] In this embodiment, the asynchronous injection of dual nozzles combined with liquid-gas dual-side pressure sensors makes the urea injection volume more accurate, effectively reducing nitrogen oxide emissions and meeting the China VII emission standards. The sensor self-correction mechanism ensures the monitoring accuracy during long-term operation, while the filter blockage diagnosis based on pressure difference enhances the self-checking and maintenance capabilities of the urea injection system, reduces maintenance costs, and extends the system's service life.

[0124] The embodiments of this application will be further described below.

[0125] Figure 2 This is a graph illustrating a diagnostic method for urea nozzle malfunction according to an embodiment of this application. Figure 2As shown, the graph for diagnosing urea nozzle abnormalities can include a horizontal axis representing time and a vertical axis representing pressure. HCP2_VAR_w_[kPa] represents the raw data collected by the urea liquid path pressure sensor; EURP_VAR_FILT_w_[kPa] represents the real-time pressure signal of the urea solution. When the recovery of the valley value during the pressure drop phase of the injection cycle is abnormally weak, it can be determined as a proximal blockage; when the peak value shift during the pressure rise phase of the injection cycle is significantly increased, it can be determined as a distal blockage.

[0126] Figure 3 This is a schematic diagram of a urea nozzle abnormality diagnosis system according to an embodiment of this application. Figure 3 As shown, the urea nozzle malfunction diagnostic system includes an air source, pressure gauge, intake solenoid valve, exhaust solenoid valve, CANape, ECU, urea tank, urea filter, urea nozzle, and measuring cup. The system also includes P1, P2, and P3, where P1 represents the tank pressure (air pressure), P2 represents the urea filter pressure, and P3 represents the nozzle pressure.

[0127] Figure 4 This is a flowchart illustrating the pressure build-up process of a urea system according to an embodiment of this application. For example... Figure 4 As shown, the pressure build-up process for the urea system includes the following steps.

[0128] Step S402, urea system pressure build-up start: open the intake valve, close the exhaust valve, charge the system to the target pressure, and assign the value collected by the urea pressure sensor to the urea tank pressure to determine whether the target pressure has been achieved.

[0129] Optionally, the control unit opens the intake valve, closes the exhaust valve, and starts the air pump to charge the urea liquid circuit system to a preset target pressure; at the same time, it collects the gas circuit pressure sensor signal (which can be represented by P_gas) and the liquid circuit pressure sensor signal (which can be represented by P_liquid) in real time; when the liquid circuit pressure reaches the target pressure and the stabilization time is ≥2 seconds, the pressure is determined to be successful.

[0130] Step S404: Pressure build-up successful, injection ready. Set timer to record system operating time, which can be carried over to the next driving cycle.

[0131] Optionally, the urea system enters the injection standby state, allowing the execution of urea injection commands; at the same time, the steady-state average values ​​of P_gas and P_liquid at the current moment are recorded as the initial reference for subsequent sensor self-correction. The above reference value is only used for one initial calibration and is not stored, updated, or used in subsequent diagnostics.

[0132] Step S406, new car rolls off the production line (determine if there is a self-learning value in the ECU).

[0133] Optionally, if the flag is set, it indicates that the ECU is not a new vehicle (e.g., ECU replacement, repair return); if the flag is not set, it indicates that the vehicle is a brand new off-line vehicle. Perform a single initial sensor correction procedure, set the flag to "set", and lock it.

[0134] Optionally, if there is a self-learning value, step S412 can be executed, i.e., as follows: Figure 5 The urea pressure sensor shown can be self-learned. If there is no self-learning value, step S408 can be executed.

[0135] Step S408: Determine whether the system working time is greater than 100 hours.

[0136] Optionally, the cumulative system runtime (cumulative number of ignitions or engine running hours) is determined by a timer recorded inside the ECU.

[0137] Optionally, if the time is greater than 100h, step S414 is executed; if the time is less than 100h, step S410 is executed. Figure 7 The image shows urea injection / pressure replenishment.

[0138] Step S410, urea injection / pressure replenishment.

[0139] Optionally, the urea system performs urea injection under normal operating conditions (asynchronous injection mode), and continuously collects P_gas and P_liquid during the injection process.

[0140] Step S412, urea pressure sensor self-learning.

[0141] Optionally, perform as follows Figure 5 The urea pressure sensor shown is self-learning.

[0142] Step S414: Determine the reliability of the urea pressure sensor.

[0143] Optionally, the P_max and P_min values ​​of real-time P_liquid are compared with preset static thresholds (Δ3, Δ4); the pressure difference ΔP_filter based on the median value of P_gas and P_liquid (P_mid) is compared with a third threshold.

[0144] Figure 5 This is a flowchart illustrating the self-learning process of a urea pressure sensor according to an embodiment of this application. Figure 5 As shown, the self-learning process of this urea pressure sensor includes the following steps.

[0145] Step S502: Collect pressure change data during the pressure build-up process and maintain pressure for 20 seconds after the pressure build-up is completed, and record the average reading of the two sensors.

[0146] Optionally, the control unit opens the intake valve and closes the exhaust valve to build up the system pressure according to the target pressure; after the pressure is built up, the system is kept in a stable pressure state; during this period, the following signals are continuously collected: gas pressure sensor signal (P_gas); liquid pressure sensor signal (P_liquid); the average values ​​of the two sensors, P_gas_avg and P_liquid_avg, are calculated and recorded over 20 seconds.

[0147] Step S504: Open the near-end urea nozzle to spray at 50% opening, record the maximum pressure on the liquid path side every second, maintain for 1 minute, and take the average air pressure of the last 20 seconds.

[0148] Optionally, the near-end urea nozzle is opened and continuously sprayed at 50% opening for 60 seconds; during the spraying period, the maximum instantaneous value of the liquid path pressure (P_liquid_max_t) is recorded every second, for a total of 60 values; the average value of P_liquid_max_t over the last 20 seconds is taken as the reference value of the liquid path pressure under spraying conditions: P_liquid_jet. At the same time, the gas path pressure is continuously collected during the 60 seconds of spraying, and the average value is taken and recorded as: P_gas_jet.

[0149] Step S506: Take half of the average value of the air pressure difference during the pressure holding and injection processes as the correction amount. Subtract the correction amount from the larger of the liquid circuit pressure and the smaller of the air circuit pressure, and add the correction amount to make the pressure values ​​equal and centered. Then solidify this coefficient for subsequent diagnosis.

[0150] Optionally, calculate the gas-liquid pressure difference: ΔP_ref = |P_gas_jet – P_liquid_jet|. If ΔP_ref ≤ 0.5 bar, the sensor consistency is considered good, and no correction is needed; if ΔP_ref > 0.5 bar, perform a single offset correction.

[0151] Step S508: Determine whether data storage is complete.

[0152] Optionally, check whether the ECU has successfully written P_gas_offset, P_liquid_offset and InitCalibFlag to Flash; if the retry fails and triggers a "sensor calibration failure" fault code (DTC), disable the urea system and prompt after-sales service.

[0153] Optionally, if so, then step S510 is performed, that is, as follows: Figure 6 The urea system shown will learn itself; otherwise, proceed to step S502.

[0154] Step S510, urea system self-learning.

[0155] Optionally, perform as follows Figure 6 The urea system shown is self-learning.

[0156] Figure 6 This is a flowchart illustrating another self-learning process for a urea pressure sensor according to an embodiment of this application. Figure 6 As shown, the self-learning process of this urea pressure sensor includes the following steps.

[0157] Step S602: Control the two nozzles to spray at a 50% duty cycle (spray interval 0.5s).

[0158] Optionally, two nozzles (proximal and distal) can be controlled simultaneously to perform asynchronous injection with a 50% duty cycle and an injection interval of 0.5 seconds; the injection duration is 15 seconds (covering 30 complete injection cycles, each cycle being 1 second); the urea level is maintained within 50% ± 10% during injection (through feedback from the oil level sensor to ensure consistent operating conditions); the injection strategy is not adjusted with changes in liquid level, and liquid level data is not collected for modeling.

[0159] Step S604: Monitor and record the pressure fluctuations during urea nozzle injection in real time. Calculate a maximum and minimum value (A1 / A2, B1 / B2) every 0.5s. Calculate a maximum and minimum value within 1s and calculate the average of the remaining two pressures as the median value.

[0160] Optionally, the gas pressure P_gas and liquid pressure P_liquid are read every 0.5 seconds with a period of 1 second. Within each second, four pressure sampling points are obtained: P_liquid at A1=t; P_liquid at A2=t+0.5s; P_gas at B1=t; and P_gas at B2=t+0.5s. Within each second, the following are calculated: P_liquid_max = max(A1,A2); P_liquid_min = min(A1,A2); and P_mid = (A1+A2+B1+B2) / 4.

[0161] Step S606: Use the moving average algorithm to record the maximum value Pmax, minimum value Pmin, and median value of the liquid circuit pressure within 30 injection cycles. Calculate the difference between Pmax and Pmin within one injection cycle and the median value, and take the average of the last 10 differences as the urea pressure fluctuation, which is then assigned to the theoretical urea pressure fluctuation EURP_CHECK.

[0162] Optionally, in 30 injection cycles, calculate for each cycle: ΔP_max = P_liquid_max – P_mid; ΔP_min = P_liquid_min – P_mid; take the average of ΔP_max and ΔP_min for the last 10 cycles as the factory static reference: ΔP_max_ref = avg(ΔP_max[21–30]); ΔP_min_ref = avg(ΔP_min[21–30]); write these two values ​​ΔP_max_ref and ΔP_min_ref into the ECU non-volatile memory as the sole static threshold for subsequent diagnostics.

[0163] Step S608: Based on the urea level recorded by EURP_CHECK, calculate the pressure fluctuation y when the level x is 0, i.e. the value of b, according to the relationship between pressure fluctuation and level change y=kx+b; and calculate the theoretical urea pressure fluctuation of the remaining level according to a 10% urea level gradient, and place it in the ECU storage area.

[0164] Step S610: Determine whether data storage is complete.

[0165] Optionally, check whether ΔP_max_ref and ΔP_min_ref have been successfully written to Flash; if it fails, retry once; if it still fails, trigger the "Diagnostic Baseline Establishment Failure" fault code (DTC) and disable the urea system.

[0166] Optionally, if so, step S612 is executed; otherwise, step S602 is executed.

[0167] Step S612, urea injection / pressure replenishment.

[0168] Optionally, execute as follows Figure 7 The image shows urea injection / pressure replenishment.

[0169] Figure 7 This is a flowchart of a urea injection / pressure replenishment process according to an embodiment of this application. Figure 7 As shown, the urea injection / pressure replenishment includes the following steps.

[0170] Step S702, urea injection / pressure replenishment.

[0171] Optionally, the system executes urea injection according to ECU instructions, or initiates an automatic pressure replenishment program when the liquid circuit pressure is lower than the set lower limit: controlling the intake valve to open and the exhaust valve to close, and starting the air pump to pressurize the liquid circuit; real-time acquisition of: gas circuit pressure P_gas; liquid circuit pressure P_liquid.

[0172] Step S704, urea filter element clogging monitoring function.

[0173] Optionally, perform as follows Figure 12 The urea filter element clogging monitoring function is shown.

[0174] Step S706: Is the power off for the entire vehicle?

[0175] Optionally, the vehicle's power status can be detected; if power is lost, all injection and monitoring will stop, the urea system will enter hibernation, and all fixed parameters will be retained.

[0176] Optionally, if yes, stop; otherwise, proceed to step S702.

[0177] Step S708, passive monitoring function of urea system.

[0178] Optionally, the following can be performed: Figure 8 The passive monitoring function of the urea system is shown.

[0179] Figure 8 This is a flowchart illustrating a passive monitoring function of a urea system according to an embodiment of this application. Figure 8 As shown, the passive monitoring function of the urea system includes the following steps.

[0180] Step S802: Set up a data storage device and use a moving average algorithm to dynamically record the maximum value Pmax, minimum value Pmin, and median value of the hydraulic pressure within 30 injection cycles.

[0181] Optionally, the following parameters are collected at a frequency of 1 Hz (every 1 second): gas pressure P_gas and liquid pressure P_liquid; the current instantaneous average system pressure is calculated as: P_mid = (P_gas + P_liquid) / 2; and the current gas-liquid pressure difference is calculated as: ΔP_filter = |P_gas – P_mid|.

[0182] Step S804: Determine whether the urea nozzle control duty cycle is within the range of 25%-75%.

[0183] Optionally, if yes, then step S806 is executed; otherwise, step S802 is executed.

[0184] Step S806: Calculate the difference between Pmax and the median value, and between Pmin and the median value within one injection cycle. Take the average difference of the last 10 cycles as Paver. Set up a data storage device to record 10 Paver-max and 10 Paver-min data points, which can be dynamically updated over time. This data can be carried over to the next driving cycle.

[0185] Optionally, the currently calculated ΔP_filter is compared with the factory-fixed threshold (third threshold, such as 1.2 bar): if ΔP_filter > third threshold → proceed to S812; if ΔP_filter ≤ third threshold → continue the loop collection without storing, updating, or recording history.

[0186] Step S808: Is the difference greater than the first threshold?

[0187] Optionally, if so, then step S810 is performed, that is, as follows Figure 9 The urea nozzle blockage diagnosis function is shown; otherwise, step S806 can be executed.

[0188] Step S810, urea nozzle blockage diagnosis function.

[0189] Optionally, perform as follows Figure 9 The urea nozzle blockage diagnosis function is shown.

[0190] Figure 9 This is a flowchart illustrating a urea nozzle blockage diagnosis function according to an embodiment of this application. Figure 9 As shown, the urea nozzle blockage diagnostic function may include the following steps.

[0191] Step S902: Control the two nozzles to spray at a 50% duty cycle (spray interval 0.5s).

[0192] Optionally, the ECU simultaneously controls the proximal and distal nozzles, performing asynchronous injection with a 50% duty cycle. The injection interval between the two nozzles is 0.5 seconds to create regular pressure fluctuations, facilitating subsequent monitoring. The total injection duration is 30 seconds, covering at least 30 complete injection cycles.

[0193] Step S904: Monitor and record the pressure fluctuations during urea nozzle injection in real time. Calculate a maximum and minimum value (A1 / A2, B1 / B2) every 0.5s. Calculate a maximum and minimum value within 1s and calculate the average of the remaining two pressures as the median value.

[0194] Optionally, during injection, the ECU collects the instantaneous pressure values ​​of the air pressure sensor and the liquid pressure sensor in real time at a sampling interval of 0.5 seconds: four pressure sampling points are obtained per second: A1: liquid pressure at time t; A2: liquid pressure at time t+0.5s; B1: air pressure at time t; B2: air pressure at time t+0.5s. The following calculations are made for each 1-second cycle: P_liquid_max = max(A1, A2); P_liquid_min = min(A1, A2); P_mid = (A1 + A2 + B1 + B2) / 4.

[0195] Step S906: Use the moving average algorithm to record the maximum value Pmax, minimum value Pmin, and median value of the liquid circuit pressure within 30 injection cycles. Subtract the Pmax and Pmin values ​​within one injection cycle from the median value and subtract them from the theoretical urea pressure fluctuation EURP_CHECK to determine the magnitude of the difference.

[0196] Step S908: Confirm whether the difference is greater than the first threshold.

[0197] Optionally, the ECUs use a sliding window moving average algorithm to continuously record the P_liquid_max, P_liquid_min, and P_mid data for the most recent 30 injection cycles. For each cycle, the following calculations are made: ΔP_max = P_liquid_max – P_mid; ΔP_min = P_liquid_min – P_mid. The above ΔP_max and ΔP_min are then compared with the theoretical urea pressure fluctuation EURP_CHECK: Difference 1 = |ΔP_max – EURP_CHECK| Difference 2 = |ΔP_min – EURP_CHECK|. Whether the two differences exceed the expected fluctuation range is determined as a preliminary criterion for nozzle blockage status.

[0198] Optionally, if so, then step S910 is executed, i.e. Figure 10 The urea system pre-correction function is shown. If not, then proceed to step 912, i.e. Figure 8 The passive monitoring function of the urea system is shown.

[0199] Step S910, urea system pre-correction function.

[0200] Optionally, perform as follows Figure 10 The urea system pre-correction function is shown.

[0201] Step S912, passive monitoring function of urea system.

[0202] Optionally, perform as follows Figure 8 The passive monitoring function of the urea system is shown.

[0203] Figure 10 This is a flowchart illustrating another passive monitoring function of a urea system according to an embodiment of this application. Figure 10 As shown, the passive monitoring function of the urea system may include the following steps.

[0204] Step S1002: Open the air intake valve to increase the pressure in the urea tank by 1 bar.

[0205] Optionally, the ECU controls the intake valve to open and applies additional air pressure to the urea liquid circuit system through an air pump, so that the pressure in the urea tank rises steadily by 1 bar within 3 to 5 seconds, artificially creating pressure disturbance to activate the system response characteristics.

[0206] Step S1004: Calculate the difference between the urea pressure fluctuation and the theoretical urea pressure fluctuation again.

[0207] Optionally, after the pressure increase is completed, the ECU continues to collect the hydraulic pressure fluctuation data of the current cycle, calculates the current actual pressure fluctuation amplitude, and calculates the difference with the pre-stored theoretical urea pressure fluctuation EURP_CHECK.

[0208] Step S1006: Is the difference greater than the second threshold?

[0209] Optionally, if ΔP_diff > the second threshold (e.g., 1.0 bar), then it is determined that the system has abnormal resistance or blockage risk, and step S1008 is executed, i.e. Figure 11 The SCR system shown has a nitrogen and oxygen feedback correction function; if ΔP_diff ≤ the second threshold, the system is determined to be in normal condition, and step S1010 is executed, i.e. Figure 8 The passive monitoring function of the urea system is shown.

[0210] Step S1008, SCR system post-nitrogen oxygen feedback correction function.

[0211] Optionally, the real-time measurement value of NOx concentration at the SCR outlet is obtained; the deviation between the theoretical NOx conversion efficiency and the actual measurement value is compared. If the deviation continues to exceed the set value, the abnormal urea pressure fluctuation result is combined to determine that the filter element is severely clogged or the nozzle is malfunctioning, and a high-priority fault code (DTC) is generated, triggering the instrument alarm and torque limiting protection mechanism.

[0212] Step S1010, passive monitoring function of urea system.

[0213] Optionally, perform as follows Figure 8 The passive monitoring function of the urea system is shown.

[0214] Figure 11 This is a flowchart illustrating the nitrogen and oxygen feedback correction function of a selective catalytic reduction system according to an embodiment of this application. Figure 11 As shown, the nitrogen and oxygen feedback correction function after the selective catalytic reduction system may include the following steps.

[0215] Step S1102, adjust the upper limit of the allowable ammonia-nitrogen ratio to 1.5~2 (classified according to the degree below the threshold).

[0216] Optionally, the ECU can determine whether the exhaust gas reduction efficiency is insufficient based on the degree of deviation between the current SCR outlet NOx concentration and the theoretical model, and accordingly make graded corrections to the upper limit of the allowable ammonia-nitrogen ratio.

[0217] Step S1104: Confirm whether the SCR system conversion efficiency is lower than the threshold.

[0218] Optionally, the ECU calculates the real-time conversion efficiency of the current SCR system; if the conversion efficiency is lower than a preset threshold (e.g., 75%), it is determined that the system has insufficient urea injection or catalytic failure risk, and step S1108 is executed.

[0219] If the conversion efficiency is not lower than the threshold, the system is considered to be working normally, and this process is stopped.

[0220] Step S1106, passive monitoring function of urea system.

[0221] Optionally, execute as follows Figure 8 The passive monitoring function of the urea system is shown.

[0222] Figure 12 This is a flowchart illustrating a urea filter element clogging monitoring function according to an embodiment of this application. Figure 12 As shown, the urea filter clogging monitoring function may include the following steps.

[0223] Step S1202: Reuse the intermediate value of the liquid circuit pressure in the data storage of the passive monitoring function of the urea system.

[0224] Optionally, the ECU can retrieve stored intermediate hydraulic pressure data, which is dynamically calculated by a moving average algorithm over the most recent 30 injection cycles and stored in a non-volatile data memory for real-time comparison in this process.

[0225] Step S1204: Check whether the urea nozzle control duty cycle is within the range of 25%-75%.

[0226] Optionally, the ECU reads the current control duty cycle command value of the urea injector:

[0227] If the duty cycle is within the range of 25% to 75% (inclusive), the current system is considered to be in a stable working state, and the pressure difference can be effectively judged, and step S1208 is executed; if the duty cycle is below 25% or above 75%, the injection disturbance is considered to be too large, and the pressure fluctuation is interfered with by the control signal, so it is not involved in the diagnosis, and the process returns to step S1202 to wait for the next cycle.

[0228] Step S1206: Difference between the urea tank pressure (air pressure) and the urea liquid line pressure to determine if the urea filter is clogged.

[0229] Optionally, the ECU collects the instantaneous value of the current gas pressure sensor, denoted as 13P_gas, and calculates the difference between the instantaneous value and the reused intermediate value of the liquid pressure 13Pmid13.

[0230] Step S1208: Is the difference greater than the threshold?

[0231] Optionally, if 13ΔP_filter13 > 13 threshold, the filter is considered severely clogged, and the process stops; if 13ΔP_filter13 ≤ 13 threshold, the system is considered normal, and step S1210 is executed. Figure 8 The passive monitoring function of the urea system is shown.

[0232] Optionally, if so, proceed with the steps.

[0233] Step S1210, passive monitoring function of urea system.

[0234] Optionally, after determining that the filter element is clogged, the ECU automatically activates the passive monitoring function of the urea system to maintain continuous low-power monitoring of system pressure and support long-term tracking and confirmation of fault status.

[0235] Figure 13 This is a flowchart illustrating the reliability assessment of a urea pressure sensor according to an embodiment of this application. Figure 13 As shown, the reliability determination of the urea pressure sensor may include the following steps.

[0236] Step S1302: Determine the reliability of the urea pressure sensor.

[0237] Optionally, after a new vehicle rolls off the production line or when the system first meets the operating conditions, the ECU initiates the urea pressure sensor reliability judgment process to perform self-calibration and reliability assessment on the measurement consistency between the gas pressure sensor and the liquid pressure sensor.

[0238] Step S1304: Collect pressure change data during the pressure build-up process and maintain pressure for 20 seconds after the pressure build-up is completed, and record the average reading of the two sensors.

[0239] Optionally, the ECU controls the urea supply pump to start pressure building and collects dynamic pressure data from the gas and liquid pressure sensors in real time during the pressure building process. After pressure building is completed, it enters the pressure holding state and lasts for 20 seconds. During this period, continuous sampling is performed, and the average value of all readings from the two sensors during the pressure holding phase is calculated and recorded as P_gas_avg and P_liquid_avg.

[0240] Step S1304: Open the proximal urea nozzle to spray at 50% opening, record the maximum pressure on the liquid path side every second, maintain for 1 minute, and take the average hydraulic pressure and average air pressure of the last 20 seconds.

[0241] Optionally, the ECU controls the proximal urea nozzle to start injection at a 50% duty cycle for 60 seconds; the instantaneous maximum value of the liquid circuit pressure is collected once per second (due to injection fluctuations), and the gas circuit pressure is collected simultaneously; after the injection ends, the average value of the liquid circuit pressure in the last 20 seconds is recorded as P_liquid_final, and the average value of the gas circuit pressure is recorded as P_gas_final.

[0242] Step S1306: Take half of the average value of the air pressure difference during the pressure holding and injection processes as the correction amount. Subtract the correction amount from the larger of the liquid circuit pressure and the smaller of the air circuit pressure, and increase the correction amount to make the pressure values ​​equal and centered. Refresh the sensor correction amount for subsequent diagnosis.

[0243] Optionally, the ECU calculates the gas-liquid pressure difference between the two stages (pressure holding and injection): pressure holding stage difference: ΔP1=|P_gas_avg–P_liquid_avg|; injection stage difference: ΔP2=|P_gas_final–P_liquid_final|; take the average of the two; and use half of ΔP_avg as the sensor correction amount.

[0244] Step S1308: Is the correction amount greater than the threshold?

[0245] Optionally, the ECU determines whether the currently calculated correction amount, Correction, is greater than a preset threshold (e.g., 0.5 bar). If Correction > threshold, it is determined that the sensor has a significant deviation, and step S1310 is executed. If Correction ≤ threshold, it is determined that the sensor is basically reliable, and step S1312 is executed.

[0246] Step S1310: Read the values ​​of the two pressure sensors during the pressure holding process, compare them with the theoretical pressure holding value, determine the sensor with the larger deviation value, and output a sensor reliability reminder.

[0247] Optionally, the ECU reads P_gas_avg and P_liquid_avg recorded in the pressure holding stage in step S1304, compares them with the preset "theoretical pressure holding value" (stored in the ECU and calibrated according to system specifications), and calculates their respective absolute deviations.

[0248] Step S1312: Pressure build-up successful, injection ready. Set timer to record system operating time, which can be carried over to the next driving cycle.

[0249] Optionally, the ECU confirms that pressure build-up and calibration are complete, and the system enters the injection-ready state; it starts the system operating timer to record the cumulative running time (in hours) of the urea system since startup; the timer data is written to non-volatile memory and can be carried over to the next driving cycle for subsequent triggering of periodic calibration.

[0250] Figure 14 This is a schematic diagram of a fault type determination device for a vehicle's gas-driven urea system according to an embodiment of this application. Figure 14 As shown, the fault type determination device 1400 of the gas-driven urea system in the vehicle includes a first control unit 1402, a calibration unit 1404, a second control unit 1406, and a determination unit 1408.

[0251] The first control unit 1402 is used to control the acquisition device to acquire the actual first pressure borne by the urea tank in response to the air-driven urea system being in a first working state. The first working state is used to indicate the state of urea in the urea tank flowing to multiple urea nozzles. A target pressure is applied to the urea tank, and the urea in the urea tank flows to multiple urea nozzles through the target pressure.

[0252] The calibration unit 1404 is used to calibrate the acquisition device in response to a pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, thereby obtaining a calibrated acquisition device, wherein the pressure difference between the first pressure and the target pressure acquired by the calibrated acquisition device is less than the pressure threshold.

[0253] The second control unit 1406 is used to control the state of the air-driven urea system to switch from a first working state to a second working state, and in the second working state, to control the calibrated acquisition device to acquire the second pressure of the urea nozzle. The second working state is an injection state in which urea is injected into the gas discharged from the vehicle alternately using multiple urea nozzles, and the second pressure is used to represent the pressure applied by the urea nozzle when injecting urea.

[0254] The determination unit 1408 is used to determine the fault type of the gas-driven urea system based on the second pressure and the duty cycle of the urea nozzle.

[0255] In this embodiment, the fault type determination device for the gas-driven urea system in the vehicle described above includes a first control unit that, in response to the gas-driven urea system being in a first operating state, controls a data acquisition device to collect the actual first pressure experienced by the urea tank. The first operating state indicates the flow of urea from the urea tank to multiple urea nozzles, with a target pressure acting on the urea tank. A calibration unit, in response to the pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, calibrates the data acquisition device to obtain a calibrated data acquisition device. The pressure difference between the first pressure collected by the calibrated data acquisition device and the target pressure is less than the pressure threshold. A second control unit controls the gas-driven urea system to switch from the first operating state to a second operating state. In the second operating state, the calibrated data acquisition device collects the second pressure of the urea nozzles. The second operating state is a spraying state in which multiple urea nozzles alternately inject urea into the gas emitted by the vehicle. The second pressure indicates the pressure applied by the urea nozzles when injecting urea. By determining the fault type of the air-driven urea system based on the second pressure and the duty cycle of the urea nozzle, the accuracy of fault determination of the vehicle urea system is improved, thus solving the technical problem of low fault determination accuracy of the vehicle urea system.

[0256] According to another aspect of the embodiments of this application, a vehicle is also provided. The vehicle may include a memory and a processor. The memory stores an executable program. The processor can be used to run the program, wherein, when the program runs, it executes the fault type determination method for the gas-driven urea system in the vehicle described in the embodiments of this application.

[0257] According to another aspect of the embodiments of this application, an electronic device is also provided, the electronic device including a memory storing an executable program; and a processor for running the program, wherein the program executes the method of any one of the above when it runs.

[0258] According to embodiments of this application, a computer-readable storage medium is also provided, the storage medium including a stored program, wherein the program executes the method for determining the duration of function retention of the desiccant in a vehicle as described in the above embodiments. According to embodiments of this application, a processor is also provided, the processor being configured to run a program, wherein the program, when running, executes the method for determining the duration of function retention of the desiccant in a vehicle as described in the above embodiments. According to another aspect of embodiments of this application, a vehicle is also provided. The vehicle may include a memory and a processor. The memory stores an executable program. The processor may be configured to run the program, wherein the program, when running, executes the method for determining the duration of function retention of the desiccant in a vehicle as described in the above embodiments of this application.

[0259] Embodiments of this application also provide a computer program product. Optionally, in this embodiment, the computer program product may include a computer program that, when executed by a processor, implements the method for determining the duration of the dryer's function in a vehicle as described in the embodiments of this application.

[0260] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between units or modules may be electrical or other forms.

[0261] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units.

[0262] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, ROM, RAM, portable hard drives, magnetic disks, or optical disks.

[0263] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for determining the fault type of a gas-driven urea system in a vehicle, characterized in that, The gas-driven urea system includes multiple urea nozzles, a urea tank, and a collection device; the method includes: In response to the gas-driven urea system being in a first working state, the acquisition device is controlled to acquire the actual first pressure borne by the urea tank. The first working state is used to indicate the state of urea in the urea tank flowing to the multiple urea nozzles. A target pressure is applied to the urea tank, and the urea in the urea tank flows to the multiple urea nozzles through the target pressure. In response to a pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, the acquisition device is calibrated to obtain a calibrated acquisition device, wherein the pressure difference between the first pressure and the target pressure acquired using the calibrated acquisition device is less than the pressure threshold. The state of the gas-driven urea system is controlled to switch from the first working state to the second working state, and in the second working state, the calibrated acquisition device is controlled to acquire the second pressure of the urea nozzle. The second working state is an injection state in which multiple urea nozzles are used to alternately inject urea into the gas discharged from the vehicle. The second pressure is used to represent the pressure applied by the urea nozzle when injecting urea. Based on the second pressure and the duty cycle of the urea nozzle, the fault type of the gas-driven urea system is determined.

2. The method according to claim 1, characterized in that, The acquisition device includes a first acquisition device and a second acquisition device. The first acquisition device acquires pressure states of a liquid medium, and the second acquisition device acquires pressure states of a gas medium. In response to a pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, the acquisition device is calibrated to obtain a calibrated acquisition device, comprising: In response to the pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, in the first working state, the gas-driven urea system is controlled to perform a pressure-holding operation for a first preset time period, and during the execution of the pressure-holding operation, a first average pressure value collected by the first acquisition device and a second average pressure value collected by the second acquisition device are obtained. In the first working state, one of the plurality of urea nozzles is controlled to perform a spraying operation within a second preset time period, and during the execution of the spraying operation, a third average pressure value collected by the first acquisition device and a fourth average pressure value collected by the second acquisition device are obtained. The calibration coefficient of the acquisition device is determined using the first average pressure, the second average pressure, the third average pressure, and the fourth average pressure. The acquisition device is calibrated using the calibration coefficient to obtain the calibrated acquisition device.

3. The method according to claim 2, characterized in that, The first pressure includes liquid path pressure and gas path pressure. Using the average value of the first pressure, the average value of the second pressure, the average value of the third pressure, and the average value of the fourth pressure, the calibration coefficient of the acquisition device is determined, including: Determine the average pressure of the first average pressure and the third average pressure; Half of the average pressure is determined as the correction amount for the data acquisition device; Determine the maximum value between the liquid circuit pressure and the gas circuit pressure, and determine the difference between the maximum value and the correction amount; Determine the minimum value between the liquid circuit pressure and the gas circuit pressure, and determine the sum between the minimum value and the correction amount; The calibration coefficient is determined based on the difference and the sum.

4. The method according to claim 2, characterized in that, The acquisition device is calibrated using the calibration coefficient to obtain the calibrated acquisition device, comprising: In response to the calibration coefficient being less than or equal to the calibration coefficient threshold, the acquisition device is calibrated using the calibration coefficient to obtain the calibrated acquisition device.

5. The method according to claim 4, characterized in that, The method further includes: In response to the calibration coefficient being greater than the calibration coefficient threshold, it is determined that the acquisition device is in a fault state.

6. The method according to claim 1, characterized in that, Based on the second pressure and the duty cycle of the urea nozzle, the fault type of the gas-driven urea system is determined, including: The gas-driven urea system is tested based on the second pressure and the duty cycle, and the test results are obtained. In response to the detection result indicating that the gas-driven urea system is in a fault state, the fault type is determined based on the second pressure.

7. The method according to claim 6, characterized in that, The second pressure includes a maximum pressure, a minimum pressure, and an intermediate pressure, wherein the intermediate pressure is the average of the maximum pressure and the minimum pressure. Based on the second pressure and the duty cycle, the gas-driven urea system is tested to obtain test results, including: In response to the duty cycle being within a preset duty cycle range, a first difference between the maximum pressure and the intermediate pressure within the same injection cycle, and a second difference between the intermediate pressure and the minimum pressure within the same injection cycle are determined. Determine the average value of the first difference within a preset number of injection cycles, and determine the average value of the second difference within the preset number of injection cycles; A third difference is determined between the average of the first difference and the self-learning value of the gas-driven urea system, and a fourth difference is determined between the average of the second difference and the self-learning value, wherein the self-learning value is used to represent the expected pressure fluctuation level in the gas-driven urea system; In response to the third difference being greater than the first threshold, and / or the fourth difference being greater than the first threshold, the detection result is determined to indicate that the gas-driven urea system is in the fault state.

8. The method according to claim 7, characterized in that, The gas-driven urea system includes an intake valve and a selective catalytic reduction system, and the method further includes: In response to the detection result indicating that the gas-driven urea system is in a fault state, and the third difference is greater than the first threshold, and / or the fourth difference is greater than the first threshold, the intake valve is controlled to be in the open state. In response to increasing the first pressure in the urea tank by utilizing the air intake valve in the open state, the third difference and the fourth difference are recalculated; In response to the recalculated third difference being greater than the second threshold, and / or the fourth difference being greater than the second threshold, the conversion efficiency of the selective catalytic reduction system is determined.

9. The method according to claim 8, characterized in that, The fault type includes urea nozzle failure. In response to the detection result indicating that the gas-driven urea system is in a fault state, the fault type is determined based on the second pressure, including: In response to the detection result indicating that the gas-driven urea system is in a fault state and the conversion efficiency is less than the conversion efficiency threshold, the fault type is determined to be a urea nozzle fault.

10. The method according to claim 8, characterized in that, The plurality of urea nozzles include proximal nozzles and distal nozzles. The urea nozzle malfunction includes both proximal nozzle malfunction and distal nozzle malfunction. In response to the detection result indicating that the gas-driven urea system is in a fault state, and the conversion efficiency being less than a conversion efficiency threshold, the fault type is determined to be a urea nozzle malfunction, including: In response to the detection result indicating that the gas-driven urea system is in a fault state, the conversion efficiency is less than the conversion efficiency threshold, and the third difference is greater than the second threshold, the fault type is determined to be the distal nozzle fault. In response to the detection result indicating that the gas-driven urea system is in a fault state, the conversion efficiency is less than the conversion efficiency threshold, and the fourth difference is greater than the second threshold, the fault type is determined to be a proximal nozzle fault.

11. The method according to claim 7, characterized in that, The fault type includes urea filter cartridge failure. In response to the detection result indicating that the gas-driven urea system is in a fault state, the fault type is determined based on the second pressure, including: In response to the detection result indicating that the gas-driven urea system is in a fault state, the pressure difference between the first pressure and the intermediate pressure is determined. In response to the pressure difference being greater than a third threshold, the fault type is determined to be a urea filter element fault.

12. A fault type determination device for a gas-driven urea system in a vehicle, characterized in that, The gas-driven urea system includes multiple urea nozzles, a urea tank, and a collection device. The device includes: A first control unit is configured to control the acquisition device to acquire the actual first pressure borne by the urea tank in response to the gas-driven urea system being in a first working state. The first working state is used to indicate the state of urea in the urea tank flowing to the multiple urea nozzles. A target pressure is applied to the urea tank, and the urea in the urea tank flows to the multiple urea nozzles through the target pressure. A calibration unit is configured to calibrate the acquisition device in response to a pressure difference between the first pressure and the target pressure being greater than or equal to a pressure threshold, thereby obtaining a calibrated acquisition device, wherein the pressure difference between the first pressure and the target pressure acquired by the calibrated acquisition device is less than the pressure threshold. The second control unit is used to control the state of the gas-driven urea system to switch from the first working state to the second working state, and in the second working state, to control the calibrated acquisition device to acquire the second pressure of the urea nozzle, wherein the second working state is an injection state in which multiple urea nozzles are used to alternately inject urea into the gas discharged by the vehicle, and the second pressure is used to represent the pressure applied by the urea nozzle when injecting urea. A determination unit is used to determine the fault type of the gas-driven urea system based on the second pressure and the duty cycle of the urea nozzle.

13. A vehicle, characterized in that, include: Memory, which stores executable programs; A processor for running the program, wherein the program, when running, performs the method according to any one of claims 1 to 11.

14. An electronic device, characterized in that, include: Memory, which stores executable programs; A processor for running the program, wherein the program, when running, performs the method according to any one of claims 1 to 11.

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